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I am attempting to compute the (integral) cohomology ring structure of the 3 configuration space of $\mathbb{R}^m$ and have run into a few doubts.
Using a result of Fadell and Neuwirth, we have that conf($\mathbb{R}^m$, 3) is the total space of the fibration:
p: conf($\mathbb{R}^m$, 3) $\rightarrow$ conf($\mathbb{R}^m$, 2) given by the obvious map onto the first 2 factors with fibre homeomorphic to $\mathbb{R}^m - Q$ where $Q$ is two points.
Since $\mathbb{R}^m - Q $ is homotopy equivalent to a wedge of two $m-1$ spheres, it has cohomology groups $\mathbb{Z}$ and $\mathbb{Z}\bigoplus \mathbb{Z}$ in dimensions $0$ and $m-1$ respectfully (Mayer-Vietoris).
Similarly conf($\mathbb{R}^m$, 2) is homotopy equivalent to $S^{m-1}$ where a map is $(x,y) \rightarrow \frac{(x-y)}{|x-y]}$. Assuming trival local coefficients (where the only problem could arise when $m=2$ since otherwise the base is simply connected) we can apply the Serre spectral sequence with $E_2^{p,q} = H^p(S^{m-1}, H^q(\vee_2 S^{m-1} )) $.
An application of the UCT (since everything is free) gives that $E_2^{p,q} = H^p(S^{m-1}) \otimes H^q(\vee_2 S^{m-1} ) $
We then have that $E_2 = E_{\infty}$ since we only have cohomology in degree $0$ and $m-1$ for the base and fibre and hence there can be no non-trivial differentials.
This leads me to a few questions.
 1. In general the $E_{\infty}$ product structure doesn't determine the product structure on the total space (see for example p 29 SSAT ) but things work out in this instance since everything is a free $\mathbb{Z}$ module and of finite type? What is a necessary and sufficient condition on the $E_{\infty}$ page structure to guarantee that the product structures coincide?
 2. I know that $H^*(S^{m-1}) = \mathbb{Z}[a_1]/(a_1^2)$ where $|a_1| = m-1$ and that $H^*(S^{m-1} \vee S^{m-1}) = \mathbb{Z}[a_2]/(a_2^2) \times \mathbb{Z}[a_3]/(a_3^2)$ where $|a_2|=|a_3| = m-1$.
 Does this simply imply that $H^*($conf($\mathbb{R}^m$, 3) ) $\simeq \mathbb{Z}[a_1]/(a_1^2)$ $\otimes \mathbb{Z}[a_2]/(a_2^2) \times \mathbb{Z}[a_3]/(a_3^2)\simeq \mathbb{Z}[a_1,a_2,a_3]/(a_1^2=a_2^2=a_3^2)$? Am I missing something?
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try mathoverflow. – john mangual Sep 15 '11 at 4:43
2 Answers 2
up vote 3 down vote accepted
A couple of comments.
First, Juan S is correct in assessing the final state of the Serre spectral sequence.
Second, with regard to your point (1) the cohomology ring structure is, in this case, not determined by the multiplication on the $E_\infty$ term, even though everything is of finite type over $\mathbb{Z}$. Specifically, you have the two classes $\alpha, \beta \in (0,m-1)$, and in the spectral sequence you have that $\alpha \cup \beta = 0$ because it lands in the zero group. However, this only guarantees that the product is zero "up to filtration." You have the possibility that $\alpha \cup \beta$ becomes some linear combination of $\alpha \cup \gamma$ and $\beta \cup\gamma$ in the actual cohomology ring.
One of the biggest red flags that this actually happens is that the relations you're getting don't look symmetric. The action of the symmetric group on this configuration space permutes $\alpha$, $\beta$, and $\gamma$, and so you can't have $\alpha \beta = 0$ when neither of $\alpha \gamma$ and $\beta \gamma$ are.
Along this line, the cohomology ring is of strictly smaller rank than the candidate that you list in item (2).
One way to get the actual cohomology ring is as follows. There is a map $$conf(\mathbb{R}^m,3) \to conf(\mathbb{R}^m,2)^3 \simeq (S^{m-1})^3$$ that sends $(x,y,z)$ to $((y,z), (x,z), (x,y))$. This is a map of bundles and respects the action of the symmetric group; over any point $(x,y)$, it is homotopy equivalent to the inclusion $S^{m-1} \vee S^{m-1} \to S^{m-1} \times S^{m-1}$. This gives you a map of Serre spectral sequence in the opposite direction which is surjective. Examining this has the following consequences.
 - The map $H^*((S^{m-1})^3) \to H^*(conf(\mathbb{R}^m,3))$ is surjective, where the former is the exterior algebra $\mathbb{Z}[a_1,a_2,a_3]/(a_i^2)$ you list in (2).
 - This map is an isomorphism in degree $m-1$, and the action of $\Sigma_3$ is dual to a permutation action on $\mathbb{Z}^3$. You can choose generators so that the permutation $\sigma$ sends $a_i$ to $a_{\sigma^{-1} i}$. (Note: Cohomology is contravariant so this is a right action.)
 - The kernel in degree $2(m-1)$ is $\Sigma_3$-equivariant of rank $1$, and the image is free of rank $2$. This forces the kernel to be generated by $(a_1 a_2 + a_1 a_3 + a_2 a_3)$.
So the cohomology ring is actually $$ \mathbb{Z}[a_1,a_2,a_3]/(a_1^2, a_2^2, a_3^2, a_1 a_2 + a_1 a_3 + a_2 a_3). $$ (This is actually the hard one. You can use this result to get a grip on the configuration spaces of more points in $\mathbb{R}^m$.)
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Thank you for the clarification. I realise that I got confused by the semantics on p. 139 in McCleary where he says that the spectral sequence converges to $H^*(E,R)$ as $algebras$. – confusedmath Oct 20 '11 at 10:02
This is really a comment, but I ran out of room (and I give no gurantee it is correct)
Shouldn't there be some relation between the generators? If I've done the spectral sequence correctly there is a $\mathbb{Z}$ on the $q=0$ row in at $p=0$ and $p=m-1$. On the $q=m-1$ row there is a $\mathbb{Z} \oplus \mathbb{Z}$ at $p=0$ and $p=m-1$. I'm not sure there can be any extension problems here, and so we know the cohomology as abelian groups:
$$H^p(\text{Conf}(\mathbb{R}^3,3);\mathbb{Z}) \simeq \begin{cases} \mathbb{Z} &\text{ if } p=0 \\ \mathbb{Z}\oplus\mathbb{Z}\oplus \mathbb{Z} &\text{ if } p=m-1 \\ \mathbb{Z} \oplus \mathbb{Z} &\text{ if } p=2(m-1) \end{cases} $$
By multiplicity of the spectral sequence I think we should we should have $E_2^{0,m-1} \otimes E_2^{m-1,0} \simeq E_2^{m-1,m-1}$ So if we denote the generators of the $\mathbb


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ExhibitPearls of the Antilles: Printed Maps of Caribbean Islands
(Arts & Culture - UT Arlington and Community)
Pearls of the Antilles: Printed Maps of Caribbean Islands
October 1, 2012 through February 9, 2013
Few people would argue that Caribbean islands have not played pivotal roles in American history. From Columbus' discoveries to the U.S. Guantanamo Bay prison debate, events on islands of the West Indies have impacted our history. While most of these islands are not that distant, our personal knowledge of them is often scant. With the help of old maps, there are interesting facts to learn and more importantly, connections for us to make. Old printed maps of the Caribbean islands depict not only the geography of the islands but also reflect many of the themes of Caribbean (and American) history as well as cartographic history.
Pearls of the Antilles: Printed Maps of Caribbean Islands shows how maps of the Caribbean incorporate many of the themes of cartographic history found in maps of other geographical areas, from technical developments to increasing diversification in types of maps, and from leading "national schools" in certain time periods to such themes as the growth of a tourist map industry.
Pearls of the Antilles: Printed Maps of Caribbean Islands is located in Special Collections, 6th floor, UT Arlington Central Library and runs through February 9, 2013. Hours are 9am - 7pm Monday and 9am - 5pm Tuesday through Saturday. This exhibit is free and open to the public. For more information call _PHONE_.
Note: visit _URL_ and look at Central Library for hours during holidays. Closed November 22, 23; December 24, 25, 31, and January 1, 2013.

source: HuggingFaceFW/fineweb-edu


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The software does allow drivers to override the system anytime.
Ford is said to be testing a new technology called Geofencing Speed Limit Control.
This new tech uses advanced connected systems and some measure of driver-assist functionality to automatically match the set speed limit. In theory, when a vehicle enters a specific area, the speed limit in that particular locality is sent to the vehicle, which then automatically reduces its speed to match the speed limit. However, unlike some cars which use road signs to adjust the speed, the new tech by Ford relies on the establishment of virtual zones, with the vehicle's position being identified using GPS.
The technology is already on trial in Cologne, Germany. As per reports, Ford Software engineers, Ford's City Engagement team and city officials in Cologne have teamed up to test the system using two E-Transit vans. When the vans approach a zone, a notification pops up on the instrument cluster while the software adjusts the speed as per the limit. The software does allow drivers to override the system anytime. Future versions of this system could let drivers establish their own zones.
The trials are expected to run until March 2023. However, there are no details as to when the tech will make its way onto production models, if at all it does.

source: m-a-p/FineFineWeb


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hydroelectric power production, and the presence of significant uranium deposits. The first PEN, drawn up in 1978, emphasized the role that nuclear power would play in meeting the nation's ever-increasing need for electricity. The revised PEN of 1984 postponed the opening of the Lemoniz Nuclear Power Plant for political reasons, and it continued the mothballing of three other nuclear plants. The government decided, nonetheless, that if the demand for electricity increased by more than 3 percent, work on one of the plants might be restarted. The new PEN also emphasized the benefits of increased natural gas consumption.
More about the Economy of Spain.
Source: U.S. Library of Congress


If you poke around in your Task Manager, there's a good chance you'll see one or more "COM Surrogate" processes running on a Windows PC. These processes have the file name "dllhost.exe", and are part of the Windows operating system. You'll see them on Windows 10, Windows 8, Windows 7, and even earlier versions of Windows.
What Is COM Surrogate (dllhost.exe)?
COM stands for Component Object Model. This is an interface Microsoft introduced back in 1993 that allows developers to create "COM objects" using a variety of different programming languages. Essentially, these COM objects plug into other applications and extend them.
For example, the Windows file manager uses COM objects to create thumbnail images of images and other files when it opens a folder. The COM object handles processing images, videos, and other files to generate the thumbnails. This allows File Explorer to be extended with support for new video codecs, for example.
However, this can lead to problems. If a COM object crashes, it will take down its host process. At one point, it was common for these thumbnail-generating COM objects to crash and take down the entire Windows Explorer process with them.
To fix this sort of problem, Microsoft created the COM Surrogate process. The COM Surrogate process runs a COM object outside the original process that requested it. If the COM object crashes, it will only take down the COM Surrogate process and the original host process won't crash. For example, Windows Explorer (now known as File Explorer) starts a COM Surrogate process whenever it needs to generate thumbnail images. The COM Surrogate process hosts the COM object which does the work. If the COM object crashes, only the COM Surrogate crashes and the original File Explorer process will keep on trucking.
"In other words", as official Microsoft blog The Old New Thing puts it, "the COM Surrogate is the I don't feel good about this code, so I'm going to ask COM to host it in another process. That way, if it crashes, it's the COM Surrogate sacrificial process that crashes instead of me process."
And, as you might have guessed, COM Surrogate is named "dllhost.exe" because the COM objects it hosts are.dll files.
How Can I Tell Which COM Object a COM Surrogate Is Hosting?
The standard Windows Task Manager doesn't give you any more information about which COM object or DLL file a COM Surrogate process is hosting. If you want to see this information, we recommend Microsoft's Process Explorer tool. Download it and you can just mouse-over a dllhost.exe process in Process Explorer to see which COM Object or DLL file it's hosting.
As we can see in the screenshot below, this particular dllhost.exe process is hosting the CortanaMapiHelper.dll object.
Can I Disable It?
You can't disable the COM Surrogate process, as it's a necessary part of Windows. It's really just a container process that's used to run COM objects that other processes want to run. For example, Windows Explorer (or File Explorer) regularly creates a COM Surrogate process to generate thumbnails when you open a folder. Other programs you use may also create their own COM Surrogate processes. All the dllhost.exe processes on your system were started by another program to do something that program wants done.
Is It a Virus?
The COM Surrogate process itself is not a virus, and is a normal part of Windows. However, it can be used by malware. For example, the Trojan.Poweliks malware uses dllhost.exe processes to do its dirty work. If you see a large number of dllhost.exe processes running and they're using a noticeable amount of CPU, that could indicate the COM Surrogate process is being abused by a virus or other malicious application.
If you're concerned that malware is abusing the dllhost.exe or COM Surrogate process, you should run a scan with your preferred antivirus program to find and remove any malware present on your system. If your antivirus program of choice says everything is fine but you're suspicious, run a scan with another antivirus tool to get a second opinion.
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text:
Problem : SAP Material documents associated with goods movements can be tracked via SAP Document Flow. Material documents generated via other processes like initial entry of goods into SAP, stock input into SAP cannot be viewed via document flow.
Solution : Use Transaction code MB03. The menu path for the same is [ SAP Easy Access -> Logistics -> Material Management -> Physical Inventory -> Environment -> MB03 Material Document ]
Step 1 : Enter SAP tcode MB03 and Enter/ Search the material document number and Fiscal year
Step 2 : SAP will display the material document number which includes
- The materials associated with the material document
- Quantities, Plants etc
- Also the Accounting documents ( By clicking on the Accounting Documents button in the toolbar) associated with the material movement if any.
This post is also useful for SAP MM training and SAP PP Training students. If you have issues with SAP IDES Access, like expired user id or locked user id, please contact us and mention your SAP ID and name.
Question 1 : What is the significance of "Posting Date" in the material document?
Question 2 : Can you change the material document after it is being posted?
Question 3 : Find out some (random) material documents generated for material M-01 in the FY 2003 and write them down here
Question 4 : Do Material Document types have a Document Type? ( Similar to SAP Sales Document type )

source: openbmb/Ultra-FineWeb


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What are some alternatives to using acetate strips? I'm not interested in a specific application here, so feel free to give ideas for all types of techniques. Under what culinary circumstances, if any, can they be substituted with a silpat? Parchment paper? Other types of plastic?
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Rarely. Acetates are usually used when you need a thin, flexible backing for whatever you're making. Silpats aren't nearly as flexible, and don't have a uniformly smooth surface; you will impart a texture to whatever you're making. And you can't really cut them into whatever shape you want. Parchment paper doesn't have the strength of acetate; you can't make rings out of it. Plus it will absorb some liquid, lowering its strength further.
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Have you ever imagined, what can be as precious as gold; but as light as air? Well, I don't know about the past, but in today's time, its gold only! Yes, you read it right. Few scientists from ETH Zurich were able to convert gold in the form of a foam, which can be easily molded by hands. With this discovery, gold foam has become the lightest metal on earth, ever discovered.
Gold foam? How does it look like?
Researchers say that though gold foam is as light as air, it's difficult to tell the difference between solid gold and gold foam by naked eye. It so happens because of the aerogel that boasts the metallic luster. This amazing discovery has made the gold foam so soft that it can be molded by hand. That's possible because the gold foam consists of 98% air and only 2% of solid gold metal. Of this solid metal, over four-fifths are gold, and less than one-fifth is milk protein fibrils. This corresponds to around 20 carat gold, according to the researchers at ETH Zurich (Swiss Federal Institute of Technology). All in all, gold foam consists of a three-dimensional mesh of gold of mostly pores.
That's why the lead of this research, Raffaele Mezzenga who is a professor of Food and Soft Materials calls the gold foam as a material that is "lighter than water and almost as light as air".
How the gold foam was created?
The scientists created this the gold foam by heating milk proteins to produce nanometer-fine protein fibers, that are also called as amyloid fibrils. These fibrils were later placed in a solution of gold salt. The protein fibers interlaced to form a basic structure, along which the gold simultaneously crystallized into tiny particles. This resulted in a gel-like gold fiber network.
Gustav Nyström, the first author of the corresponding study in the journal Advanced Materials mentions,
"One of the big challenges was how to dry this fine network without destroying it,"
Where can we use the gold foam?
Scientists mention that the material holds unique properties. It is a metal, but due to its porous structure, it is also light. As a result, it can be successfully used in jewelry and watches. Besides, it can be used as a revolutionary catalyst since it has huge surface, with very little quantity. It can be used in chemical labs across the world to carry out several chemical tests on this precious metal.
Gold is not the first metal to be converted into a foam. Scientists have successfully converted copper also into a foam earlier. The copper foam is used in various researches and tests in chemical labs.


text:
White Rock (Cambria) SMCA
Shoreline Boundary Landmarks:
This area is bounded by the mean high tide line and straight lines connecting the following points in the order listed:
35° 32.85' N. lat. 121° 05.85' W. long.;
35° 32.85' N. lat. 121° 06.70' W. long.;
35° 30.50' N. lat. 121° 05.00' W. long.; and
35° 30.50' N. lat. 121° 03.40' W. long.
California Department of Fish and Wildlife
- Recreational Fishing:
- Allowed Species: None
- Prohibited Species: All
- Commercial Fishing:
- Allowed Species: Giant kelp (Macrocystis pyrifera) and bull kelp (Nereocystis spp.) under the following conditions:
- Any individual kelp harvester with a valid permit issued pursuant to Section 165 and holding a valid lease to Administrative Kelp Bed 208 may take no more than 125 tons of kelp from the portion of Administrative Kelp Bed 208 within the White Rock (Cambria) State Marine Conservation Area in any calendar month.
- Duplicate landing records must be kept on board the harvest vessel in accordance with the requirements of Section 165.
- Prohibited Species: All other living marine resources EXCEPT those listed above.
Effective as of: September 21, 2007


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South Korea's government is betting big on blockchain.
The Ministry of Science and ICT announced Thursday that it will spend KRW 113.3 billion (about USD 101.4 million) over the next five years to secure nine key technologies in four strategic sectors with the ultimate goal of developing "blockchain technology for the data economy."
The ministry plans to spend KRW 20.3 billion (almost USD 18.2 million) of that in 2021. Here's a breakdown of how they're spreading their money around.
The four strategic sectors are:
- Completely decentralized, high-performance consensus technology
- Smart contract security technology
- Blockchain technology for processing personal information and managing identity
- Blockchain data management technology for guaranteeing data sovereignty
And the technologies to be developed are, per sector:
Completely decentralized, high-performance consensus technology
– A decentralized consensus system for large-scale node networks
– Guaranteeing efficient transaction finality at the block level in large-scale networks
– Guaranteeing high-performance, large-scale transaction scalability
– Developing P2P network protocols for blockchain
Smart contract security technology
– Preventing errors and weaknesses in smart contracts through secure coding and making them safer for ordinary people to use
Blockchain technology for processing personal information and managing identity
– User ID authentication and management technology for using self-sovereign IDs
– Blockchain data encryption-based privacy protection
Blockchain data management technology for guaranteeing data sovereignty
– Technology for increasing the amount of data that can be processed through large-scale node management and distributed storage
– High-speed analysis of large-scale data in distributed storage
Nine consortiums and 53 institutions have been selected to develop the technologies. According to the ministry, industrial entities will participate with all nine of the consortiums. So the government hopes the new technologies will be put to actual industrial use, boosting the country's technical competitiveness.
Indeed, the ministry said it won't skimp on support to improve the competitiveness of South Korea's blockchain technology.


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The structural response of a molten main-chain liquid crystal polymer to an applied magnetic field has been investigated microscopically, with the microstructure being characterized as a function of field strength, time in the field and molecular weight. The application of the field to a structure in which the director wandered gradually on a scale of about 100 ~tm resulted in the formation of domains delineated by well defined boundaries. The domains were elongated along the field axis to an aspect ratio of about 8 in the case of a 1.1 T field, although for the higher field strength of 5.6 T the domains were no longer visible. Evidence is presented that the domain boundaries correspond to a director reorientation of ~ rad. Etched domain microstructure revealed a uniform distribution of crystallites, representing regions of local ordering in the material, on a scale of a few hundred nanometres. The crystallites had the form of platelets normal to the local director and acted as orientational markers across the domain boundaries.
Посилання на статтю:
Magnetic orientation and microstructure of main-chain thermotropic copolyesters / A. Anwer and A. H. Windle* // Polymer. – 1993. – Vol 34. – P. 3347-3357.


Study on perception threshold for whole-body vibration
Qiong Wu5 , Qiang Liu1 , Zhongxu Kang2 , Lijuan Zhang4 , Ruixiang Song3
5, 1, 2, 4, 3Beijing Municipal Institute of Labour Protection, Beijing, China
1Corresponding author
Vibroengineering PROCEDIA, Vol. 14, 2017, p. 244-249. _URL_
Received 9 September 2017; accepted 18 September 2017; published 21 October 2017
Copyright © 2017 - JVE International Ltd.
Abstract.
When people stay in the vibrating environment for a long time, the body may produce a series of physiological and psychological diseases. In order to evaluate the impact of vibration on the human body, the establishment of evaluation method or evaluation system is necessary. At present, most countries usually evaluate whole-body vibration based on the international standard ISO 2631-1 "Mechanical vibration and shock-Evaluation of human exposure to whole-body vibration-Part 1: General requirements". In this paper, the experiments of perception threshold of whole-body vibration were taken as the breakthrough point of evaluation method, and 12 subjects participated in the experiments. Through the experiments, comparing the provisions of ISO 2631-1, we get some different conclusions about the distribution law of perception thresholds. This also provides some data support for further experimental research.
Keywords: whole-body vibration, vibration exposure, perception threshold, mechanical vibration.
1. Introduction
Many scholars have done a lot of research on whole-body vibration [1, 2]. However, there are many parameters to evaluate the effect of vibration on the human body, such as vibration intensity, vibration frequency, vibration exposure time and subjective feelings, etc. Therefore, it is very difficult to establish a criterion or method for evaluating the effect of vibration on the human body. At present, most countries usually evaluate whole-body vibration based on the international standard ISO 2631-1 [3]. China adopted this standard in 2007, and published the recommended standard of GBT 13441.1-2007 "Mechanical vibration and shock-Evaluation of human exposure to whole-body vibration-Part 1: General requirements". In this standard, the basic evaluation method of vibration on the human body is proposed, and the evaluation factors and weighting factors are recommended. Besides, it is recommended to use the root-mean-square value of the weighted acceleration to evaluate the impact of vibration. However, the standard does not explain the source of the underlying data, such as frequency weighted factors, perception thresholds, etc., so we do not know whether these provisions and numerical value apply to the Chinese people as well. In this paper, we carried out the experimental study of the perception thresholds, and it was taken as the breakthrough point of the whole-body vibration study. A study was done to measure standing vibration perception thresholds in the vertical direction at 12.5, 20, 25, 31.5, 40, 50, 63, and 80 Hz.
2. The experiments
2.1. Test equipment
We carried out the whole-body vibration experiments by electromagnetic vibration platform. In order to eliminate the influence of ambient vibration, rubber pads were laid at the bottom of the shaking table. The vibration platform is shown in Fig. 1, and the main parameters are shown in the following Table 1.
Table 1. Parameters of the vibration platform
Modes of vibration
single frequency stimulus and swept frequency stimulus
Direction of stimulus
x , y and z axis
Frequency range of stimulus
1Hz to 600 Hz (minimum frequency interval is 0.1 Hz)
Amplitude of vibration
0 mm to 5 mm
Maximum acceleration
20 g
Maximum load
150 kg
Fig. 1. The vibration platform
2.2. The subjects
In this paper, 12 subjects participated in the experiments, including 6 females and 6males. To ensure the reliability of the experimental data, all subjects were healthy and without related diseases, such as respiratory diseases, cardiovascular diseases, skeletal and muscular diseases, etc.
The subjects were between 22 and 28 years old, and the average height was 167 cm. Body mass index (BMI) is commonly used to the standard that measure body fat levels and whether the body is health. Among the subjects, the BMI of one of them is overweight (24.0 < BMI ≤ 26.9) and the other one is severe obesity (BMI ≥ 30). The BMI of the other subjects is in the normal range (18.5 ≤ BMI < 23.9). The body condition of the subjects is shown in the following Table 2.
Table 2. Condition of the subjects
Name
Gender
Age
Height (cm)
Weight (kg)
BMI
Subj.1
Female
22
167
60
21.5
Subj.2
Female
25
160
50
19.5
Subj.3
Female
24
167
60
21.5
Subj.4
Female
28
164
54
20.1
Subj.5
Female
28
163
64
24.1
Subj.6
Female
25
170
55
19.0
Subj.7
Male
25
173
67
22.4
Subj.8
Male
28
170
60
20.8
Subj.9
Male
24
168
65
23.0
Subj.10
Male
22
168
87
30.8
Subj.11
Male
23
166
53
19.2
Subj.12
Male
24
166
54
19.6
2.3. Transducer installation
Transducer should be located so as to indicate the vibration at the interface between the human body and the source of its vibration. Therefore, in the standing experiments, we installed the transducer on the contact area between the foot and the vibration platform.
2.4. The experiment description
Before the experiment begins, we told the subjects that he would be stimulated by a random vibration, but in fact, we had set the vibration stimulus according to the certain procedures. The reason for this was to minimize the subjective judgment of the subjects, and to ensure that their response to the vibration stimulus was objective and true. When we gave the vibration stimulus, they needed to tell us whether they could feel it or not, and then we would adjust the vibration stimulus according to the procedures.
We adopted a cyclic down-up-down-up approach to carry out the whole-body vibration experiments. First of all, we gave the subjects a stimulus level of 0.1 m/s2, which was distinctly discernable to all of the subjects. Then we descended the level of stimulation with an equal acceleration value, but the subjects were not told. Subjects need to tell us whether they could feel it or not about every vibration stimulus. We continued to descend the stimulus level until the subjects could not feel the vibration, then we ascended the stimulus to the last level. Subsequently we descended the stimulus level with a smaller equal acceleration value. Repeated the above steps until we got the subjects' perception threshold.
We used the sine stimulus signal in the vertical direction to carry out the whole-body vibration experiments. Through the method of swept frequency, we got the resonance frequency of the vibration platform was 16 Hz in the vertical direction, so we avoided this frequency in the experiments. The frequencies included 12.5, 20, 25, 31.5, 40, 50, 63, and 80 Hz. Every subject needed to complete the vibration stimulation test at all the above frequencies. Besides, taking into account the reliability and repeatability of the data, each subject was tested on two different dates.
Strong noise could affect the vibration perception of the subjects, so the experiments were carried out under background noise of 39 dB(A) [4]. The subjects needed to take off the shoes, stand still and relax. The experimental photo is shown in Fig. 2.
Fig. 2. The vibration experiment
2.5. The results
As briefly described in the experiment description, the vertical tests were conducted using the cyclic down-up-down-up approach covering a range of 12.5 to 80 Hz in 1/3 octave. Twelve test subjects were employed, 6 male and 6 female, ranging in age from approximately 22 to 28, with all of them having a healthy body. The stimulus was sinusoid of one minute duration. Table 3 shows the perception thresholds of different subjects on two different dates.
The test results show that perception thresholds of the whole-body vibration distribution in the range of 0.005-0.05 m/s2. The perception thresholds have some difference between the subjects. Also, the perception thresholds of each subject are varied at different test time. We calculate the average of twice perception thresholds test for each subject and draw the curve distribution.
The ISO2631-1 standard states that persons can detect a Wk weighted vibration with a peak magnitude of 0.015 m/s2, therefore, the root-mean-square value is 0.010 m/s2. Combining the weighted factors specified in the standard, we can calculate the linear result of perception thresholds in different frequencies. They are shown in Table 4.
Table 3. Perception thresholds of the subjects
Name
Acceleration, root-mean-square value (arms)
12.5 Hz
20 Hz
25 Hz
31.5 Hz
40 Hz
50 Hz
63 Hz
80 Hz
Subj. 1
0.053
0.020
0.017
0.033
0.041
0.038
0.016
0.014
0.012
0.011
0.007
0.009
0.009
0.011
0.013
0.012
Subj. 2
0.020
0.030
0.030
0.022
0.037
0.028
0.042
0.033
0.024
0.038
0.044
0.030
0.025
0.035
0.036
0.


text:
Scenario: A game starts at noon and the last out is made at 16.10. During the game there is a 60-minute delay for rain and a 10-minute delay to adjust the umpire crew after the plate umpire twists an ankle.
As the official scorer, what do you put down as the duration of the game in your report?
A – 3 hours.
B – 3 hours 10 minutes.
C – 4 hours.
D – 4 hours 10 minutes.
Highlight the text below to reveal the answer:
Answer: B – 3 hours 10 minutes.
Rule 10.02(l) states:
Time required to play the game, with delays deducted for weather, light failure or technological failure not related to game action.
Rule 10.02(l) Comment states:
A delay to attend to the injury of a player, manager, coach or umpire shall be counted in computing time of game.


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I have a cookie for language. I want to check if this cookie is set and to check its value to redirect the user to specific page. the cookie name is Lang and its value might be En,Fr,or Ar
if (req.http.Cookie ~ "Lang"){
//now i want to check for the cookie value
//if LANG=="Ar"
// set req.url = req.url "CookieValue"
}
anybody know how to check for cookie value in varnish??
Thanks
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1 Answer 1
up vote 2 down vote accepted
Since all the cookies - both name and value - are in the req.http.Cookie string, you should be able to check for both name and value at the same time. Unfortunately, Varnish does not have any specialized methods for dealing with cookies - you must use regular expressions.
It is important to note that cookies are delimited by a semicolon and white space, for example:
cookie1=abc; cookie2=def
We know, therefore that our cookie is either at the start of req.http.Cookie, or is preceded by a semicolon and white space, and either ends with a semicolon, or is at the end of req.http.Cookie. Given this, we can construct a regex that will match our cookie and the semicolon, if any. Something like:
(^|;\s*)(Lang=En)(;|$)
Briefly, going through the above we have:
 - First set of brackets - match the start:
 - ^ means start of string
 - | means OR
 - ; is taken literally (i.e. semicolon)
 - \s means white space
 - * means one or more repetitions of the preceding character
 - Summary: either the start of the string or a semicolon followed by white space
 - Second set of brackets - match the cookie:
 - Lang is the name of the cookie
 - En is the value of the cookie
 - Third set of brackets - match the end
 - ; is taken literally (i.e. semicolon)
 - | means OR
 - $ means end of string
 - Summary: either a semicolon or the end of the string
Using the above, we can check for the cookies and perform some action on them:
if (req.http.Cookie ~ "(^|;\s*)(Lang=En)(;|$)"){
 //do something with En
} elseif (req.http.Cookie ~ "(^|;\s*)(Lang=Fr)(;|$)") {
 //do something with Fr;
}
There may be better ways, or more efficient regexes (unfortunately, varnish doesn't have user defined variables - which means you can't use regex capture groups) - but hopefully this will do the job.
Arguably, you could construct a regex with a capture group using regsub, and set that as a subdomain, perhaps something like:
set req.url = regsub(req.http.Cookie, "(?:^|;\s*)(?:Lang=(.*?))(?:;|$)", "\1.")+"example.com";
In the case of 'Lang=en', you would capture the 'en' add a period (.) and prepend to 'example.com' giving you en.example.com. I'd suggest though directly using a cookie to set the URL - without a lot of error checking - would be a very bad solution. If you just have 3 languages, a couple of if statements and a default would be much safer.
Note: the above is untested, and regexes aren't my forte - expect a few mistakes - but hopefully the premise works.
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in [sub vcl_recv] i have added this line [set req.url = req.url "/en";] is it supposed change my request url from example.com to _URL_ ???Thanks for your help – Alaa Alomari Jan 12 '12 at 8:08

a) Firstly you need a 'normalized' req.url (i.e. how do you know the url isn't currently _URL_.php - adding /en to the end of that wouldn't be good - you could use a regex to do the replacement, but that should be asked as a different question. b) you need a plus sign (+) for concatenation in Varnish. c) changing req.url will only 'internally' change the path (i.e. a rewrite) it will not send a 301 (or 302) redirect to the client. – cyberx86 Jan 12 '12 at 10:35
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text:
We are currently looking for an experienced Office Admin for a full time, direct hire position in the Annapolis, MD area. Position is available to start immediately.
- Answers and directs telephone calls.
- Processes mail.
- Performs clerical tasks such as typing, filing, copying and faxing.
- Orders supplies for the office.
- Maintains and updates various databases.
- Provides administrative support to Contract, Project and Office managers.
- Processes transmittals, submittals, purchase orders, change orders.
- Accounts Payable and account reconciliations.
- Verifies and processes invoices, maintains vendor files.
- Orders plans and tracks status.
Knowledge, Skills, and Abilities required:
- Knowledge of standard accounts payable policies and procedures.
- Ability to understand and interpret vendor invoices, statements, and other request for payments.
- Ability to process computer data and format and generate reports.
- Strong communication and interpersonal skills.
- Knowledge of general accounting principles.
- Microsoft Word, Excel, and Outlook.
- Timberline Accounting Software
Please apply for immediate consideration. Thank you!


text:
This ethnographic photography exhibition by Amy Masko, Assistant Professor of English at Grand Valley State University, is the result of her research project investigating the life of Nana Otu, a young Fraanketanyi, and a flag dancer in Asafo No. 1 Company in Cape Coast Ghana. Historically the Asafos served as militia groups. Today the groups perform exclusively as part of spiritual rituals.
The photographs illustrate the life of the Asafo. The exhibit highlights the Fetu Afeye Festival, a harvest festival held in Cape Coast every August. The Asafo play a significant role in this festival, holding spiritual rituals to bless the lagoon for bountiful fishing, burning cleansing fires to clear negative spirits, and holding drumming rituals to communicate with the ancestors.
Art Gallery, _PHONE_


text:
The primary function of a mechitza in a synagogue is to establish a separation between the men's prayer area and the ezrat nashim. This practice traces its roots back to the time of Beit Hamikdash, during which the term 'ezrat nashim' seems to have been coined. Over the years, the need for this separation has evolved into a more intricate and challenging requirement. The mechitza is tasked not only with delineating gender boundaries, but also with ensuring comfortable and dignified accessibility for women, while serving as an artistic and well-designed element that fosters a sense of space rather than a 'wall.'
Traditional mechitzot occupy a central place in the synagogue's aesthetic. Often fashioned as decorative wooden partitions, they demarcate the Ezrat Nashim from the men's prayer area. Their top part often features designed and carved portholes (sometimes covered with a matching decorative curtain).
In addition to elegant appearance, efficiency and comfort of use are of vital importance. Traditional mechitzot can take the form of a fixed and sturdy structure, comprised of thick and intricately carved wooden panels, or a mobile partition — either static or folding — made of easily transportable and storable panels.
At Lavi Furniture, we tailor each mechitza to the unique needs of the congregation, considering the structure of the synagogue in terms of size, shape, and functions, while paying respectful attention to the worshippers' needs.


text:
About Supercritical Girl
"With Great Properties, comes Great Opportunities"
Supercritical Girl (@cindy_supercritical) found out about the wonders of supercritical fluids from a special course in thermodynamics during her undergraduate days, where she learnt about the applications of supercritical carbon dioxide for solvent-free extraction. Ever since then, she has been fascinated with the powers of supercritical fluids and its applications.
With the Singapore-MIT Alliance (MEBCS) scholarship for both MSc and PhD studies, she began her journey of working with supercritical fluids. (Thesis title: Fabrication of controlled release devices using supercritical Fluid Techniques). She spent some time at MIT (Chemical engineering department) at Professor Jefferson Tester's lab, learning and working with postgraduate students in MIT on supercritical fluid equipment. She subsequently developed her first set of custom built supercritical CO2 processing unit for her research. Completing her PhD in 2008, she joined leading supercritical CO2 Research and Development company in the Netherlands FeyeCon D&I B.V as Project Leader, working on projects using supercritical CO2 for food, pharma and medical applications.
Returning home to Singapore together with her family, Supercritical Girl then joined Newcastle University, Singapore as Assistant Professor with the Chemical Engineering Program (Newcastle University in Singapore). She continues to pursue her research in supercritical CO2 applications and is committed to develop new applications for food and sustainable development. Supercritical Girl is committed to increasing the awareness and knowledge of supercritical fluid processes to the public as well as local industries. She held the role of Director of Excellence Learning and Teaching for Newcastle University in Singapore and as acting Director of Operations for Chemical Engineering Program, and was also promoted to Associate Professor in 2018.
Today, Supercritical Girl is back at her alma mater (National University of Singapore, Department of Chemical and Biomolecular Engineering) where she is looking forward to new and exciting ways to enhance the learning experiences of students and to integrate her research interests with her teaching.
She believes in the advantages of supercritical CO2 research, because of the unique properties of the fluid! "With GREAT PROPERTIES, come GREAT OPPORTUNITES"


text:
Minimum Number of Distinct Eigenvalues of Graphs
Electronic Journal of Linear Algebra
Symmetric matrix, Eigenvalue, Join of graphs, Diameter, Trees, Bipartite graph, Maximum multiplicity
The minimum number of distinct eigenvalues, taken over all real symmetric matrices compatible with a given graph G, is denoted by q(G). Using other parameters related to G, bounds for q(G) are proven and then applied to deduce further properties of q(G). It is shown that there is a great number of graphs G for which q(G)=2. For some families of graphs, such as the join of a graph with itself, complete bipartite graphs, and cycles, this minimum value is obtained. Moreover, examples of graphs Gare provided to show that adding and deleting edges or vertices can dramatically change the value ofq(G). Finally, the set of graphs Gwith q(G) near the number of vertices is shown to be a subset of known families of graphs with small maximum multiplicity
Ahmadi, Bahman; Alinaghipour, Fatehmeh; Cavers, Michael S.; Fallat, Shaun; Meagher, Karen; and Nasserasr, Shahla, "Minimum Number of Distinct Eigenvalues of Graphs" (2013). Mathematics Faculty Articles. 75.


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Philips Sleep Apnea Device Recall - Click for details
Your Questions — 4 minutes
What types of water should be used in your continuous positive airway pressure (CPAP) device?
Biron
Distilled, demineralized, bottled, ozonated, boiled or tap water? Which ones are recommended, and which ones should be avoided?
CPAP tanks are usually made of materials that tend to degrade when in contact with heated minerals. Therefore, using mineral-free water prevents premature wear and build-up of a whitish residue. That's why only two types of purified water are recommended for CPAP tanks: demineralized water and distilled water.
Distilled water
This water is free of minerals and microorganisms. It is the purest commercially sold water as it contains the fewest organic contaminants.
Demineralized (or deionized) water
This water has been stripped of all its salts and minerals using a process of demineralization (or deionization).
You can find both types of water in grocery stores, pharmacies, and supermarkets. To avoid potential contamination, keep the bottles in a cool, dark place.
Also, there are domestic water demineralization devices, such as reverse osmosis systems. When properly maintained, they make it possible to use tap water in CPAP equipment.
The following types of water are not recommended for everyday use but can be used occasionally for troubleshooting. As they contain minerals (calcium, magnesium, iron, etc.), it is necessary to thoroughly clean the tank after using the device (see the box for cleaning instructions).
Ozonated water
Ozonation is a water sterilization process designed to destroy pathogens. Indeed, ozone is an oxidizing agent and a powerful disinfectant capable of eliminating viruses and bacteria that may have survived the filtration stage.
Boiled water
Contrary to popular belief, using tap water is not harmful to you, as long as it is safe to drink. Still, it can affect the lifespan of your accessories, especially your reservoir.
Tap water
Contrary to popular belief, using tap water is not harmful to you, as long as it is safe to drink. Still, it can affect the lifespan of your accessories, especially your reservoir.
Bottled spring water shares the same properties as tap water.
Note that a water softener does not make tap water usable since it usually removes only calcium and magnesium. Purifiers equipped with a carbon filter (e.g., Brita) reduce the chlorine content without removing minerals and leave impurities that can damage your equipment.
Important reminders
 - Never add essential or scented oils to the water as they can damage the device.
 - Remember to empty and rinse the tank after each use.
 - Every week, wash the tank with warm, soapy water and rinse with plenty of clean water. You can place certain models in the top rack of the dishwasher (check the manufacturer's instructions). Allow it to dry away from direct sunlight or any heat source before reassembling.
 - In case of mineral deposits, soak the tank for 10 minutes in a solution of one part white vinegar (5% acetic acid) to two parts water. Empty the solution and rinse thoroughly before letting it dry.
Biron


text:
Estimated reading time: 6 minutes
Ear piercing in infants has been a cultural practice for centuries, with proponents and opponents expressing varying views on its appropriateness. The decision to pierce a baby's ears is deeply personal and often influenced by cultural, religious, and familial factors. Let's explore the different perspectives on piercing babies' ears. Providing a well-rounded understanding of the debate and the ethics of baby ear piercing.
Cultural and Familial Traditions:
Many families view ear piercing as a cultural or familial tradition, often passed down through generations. In some cultures, piercing a baby's ears is seen as a rite of passage or a symbol of cultural identity. Families that hold these beliefs may choose to pierce their infants' ears shortly after birth as a way of honouring their heritage. Other cultures wait until much later as having your ears pierced is considered a more adult thing. In the UK, many parents will take their children to get pierced at the end of year 6.
Respect for cultural diversity and sensitivity to cultural practices are important considerations in discussions about baby ear piercing. For many communities, ear piercing holds cultural significance and is deeply ingrained in traditions and customs. Criticising or condemning these practices without understanding their cultural context can be perceived as ethnocentric or culturally insensitive.
Religious beliefs can significantly impact the decision to pierce a baby's ears. Some religious traditions have specific rituals or ceremonies associated with ear piercing. Others may discourage or prohibit the practice altogether. Families often consult religious leaders and adhere to specific guidelines within their faith when deciding whether or not to pierce their baby's ears. When we have a family that comes as part of their religious beliefs, we need be informed ahead of time. We can then then comply on the piercing day with the correct ear piercing process.
Ethical Concerns of Baby Ear Piercing:
On the opposing side of the debate, there are medical and ethical concerns associated with piercing infants' ears. Critics argue that subjecting a baby to the pain and potential risks of infection is unnecessary. We practice painless ear piercing in our clinic.
Infants may not have the ability to consent to the procedure, raising ethical questions about bodily autonomy. Some healthcare professionals recommend waiting until a child is old enough to express their own desire for ear piercing. Allowing them to participate in the decision-making process.
We are of the opinion that once a child is old enough to communicate their feelings, they need to be prioritised in the decision making process. You can read our negative reviews that we "don't know what we're doing" because we have shown parents the door when the child made it clear they didn't want to have their ears pierced. We are ok with that, in fact, proud!
Parental Autonomy vs. Child Autonomy:
One of the central ethical dilemmas surrounding baby ear piercing is the tension between parental autonomy and child autonomy. Parents have the legal authority to make decisions on behalf of their children, including decisions about their appearance. However, some argue that children should have the right to bodily autonomy and self-determination, which includes the right to decide whether or not to undergo cosmetic procedures like ear piercing.
Waiting until the child is old enough to consent:
Whilst this sounds like a good idea on the surface, we also need to be aware of the downside of leaving it until the child is older. We see children with a huge amount of anxiety coming in for ear piercing. This anxiety primarily comes from her school friends telling her how "painful" it was, how they "nearly died" from the pain and could not "sleep for days" post the piercing. By the time they get to Lorena they're are an axious mess. They don't believe when she promises that it will be pain free and the next hour is full of dread and anxiety. Not to mention the emotional build up the day.
Also, we need to consider that the older the child gets the higher the chances of complications such as infections. Parent's tend to be under the impression that an older child can look after their piercing. Please consider the general state of the average 13 year old's bedroom before placing this responsibility on their child. Lorena is passionate about this point and she equates it to a parent finally allowing a child to have a pet but only if she agrees to do 100% of the care of that pet. In other words, setting up the child to fail…because…she's…a child…unable to keep her promise.
Teens face a different type of problem. Having waited so long to have their ears pierced they want to change their earrings as soon as possible. Ensuring an infection to the area. Sometimes they will exchange earrings with their friends at school straight from one ear to the other. Every single time that we have had a complication with one of our piercings (because we want to know immediately and see you if something goes wrong regardless of how much time has passed) the child has walked in with a different, and/or dirty earring on.
Practical and Medical Considerations of the ethics of Baby Ear Piercing:
Practical considerations, such as hygiene and aftercare, also play a role in the debate. Infants require meticulous care to prevent infection, and parents must commit to cleaning the pierced ears regularly.
Additionally, concerns about potential allergic reactions to certain metals used in earrings may influence the decision-making process. What we do know is that infections among infants are rare whilst on older children the infection rate is as much as 50%. This is because parents do the aftercare rather than leave it to an older child. Also, infants tend to not play with their ears therefore keeping bacteria at bay.
In case of infections, antibiotics is the only way to fight the infection. The ear is an area of the body that doesn't fight off infection on it's own so a prescription from your doctor is the only way to fight it.
The Importance of Informed Consent:
One common thread in the discussion is the importance of informed consent. Regardless of cultural, religious, or familial traditions, advocates for waiting until a child can express their own wishes argue that individual autonomy should be respected.
Allowing the child to participate in the decision-making process when they are older may foster a sense of ownership over their body. Cultures that pierce as an infant argue that it's only one of many decisions that the parents make for this children. Doing it young has huge benefits with future possible complications. We have made the decision to not pierce a child that says NO or shows signs of fear.
Making the decision to pierce your baby or not:
The debate surrounding ear piercing in infants is nuanced and multi-faceted. Cultural, religious, and familial traditions often clash with medical and ethical considerations. Ultimately, the decision to pierce a baby's ears is a personal one that falls on the parent. It should be made with careful thought and consideration of the child's well-being. As societal perspectives evolve, conversations around informed consent and bodily autonomy will likely continue to shape the way we approach this age-old practice. Ultimately, this is a personal decision made by the child's family. Along with the piercer's responsibility to have the child's best interest at heart. Sadly, we have seen in our practice that some parents have other priorities above their child's.
We take ear piercing very seriously. We use numbing cream to make the child have a pain free procedure that both parents and child can enjoy. You can call us on 0800 _PHONE_ and you can book online HERE. You can book a free video consultation if you wish to speak to Lorena directly.


text:
Choose a Product Line:
Have a technical question?
Call: _PHONE_
Why ZIP System Performs Better
1Why ZIP System Sheathing is Superior to Housewrap
This document discusses the characteristics of ZIP System Sheathing and why it is superior to the traditional housewrap.
2ZIP System Sheathing Air Movement Test Methodology
This document discusses the testing methods use to assess the air barrier performance of ZIP System Sheathing.
3ZIP System Sheathing and Air Barrier Performance
General information about air barriers, how they function and how they affect energy efficiency is discussed within this document.
4ZIP System Air Barrier Testing Methods
This technical tip disccuses the various test methods used to evaluate the air barrier performance of ZIP System sheathing as an air barrier material (ASTM E2178) and air barrier assembly (ASTM E2357).


text:
NRG says the system differs from Scada systems, which use sensors to detect component faults but often require trained maintenance staff to understand the data. TurbinePhD instead uses digital signal-processing techniques to detect component wear before a fault develops. Sensors with embedded processors use algorithms to diagnose problems and then transmit data to a secure website.
"Our system borrows technology from the aerospace industry to diagnose early-stage wear - months in advance of a fault - and then to accurately estimate the remaining useful life of each component," said Eric Bechhoefer, chief engineer at NRG Systems. "We also eliminate the need for a diagnostic engineer by integrating data into a single, readily understandable health indicator for each component. The data can be read and acted upon by anyone."
NRG says the system integrates multiple condition indicators into this single health indicator, eliminating the need for the engineering interpretation required by traditional systems. These indicators are accessible online, along with all of the data supporting the diagnosis. The product, which is currently in beta testing, is set to be launched in the summer.
The news came as NRG chief executive Jan Blittersdorf was recognised by the US White House as one of 10 Champions of Change for renewable energy.


text:
From left: Richard Ehst, President and Chief Executive Officer of Customers Bank, Dr. Rudy Ruth, Executive Director of Alvernia University's Holleran Center for Community and Global Engagement, Thomas Minick, Vice President for Institutional Advancement, Dr. Jennifer Murray, Assistant Superintendent for Teaching and Learning for the Reading School District, Dr. April Halligan-Rostek Principal of Millmont Elementary School, John R. Loyack, President of Alvernia University, Laura Cordero, Reading Youth Initiative Program Manager and AnNette Hines, Director of Cultural Advancement for Customers Bank.
Funds support Alvernia's Reading Youth Initiative
On Wednesday, March 10, 2021, Customers Bank and Alvernia University held a check presentation ceremony to recognize the bank's contribution of $150,000 to the university to support the Reading Youth Initiative. The Reading Youth Initiative aims to enhance academic progress through academic enrichment, mentoring and support for healthy choices in children who live or go to school in the Reading area.
The Reading Youth Initiative, conducted by the university at Millmont and Tyson-Schoener Elementary Schools, is offered through the Holleran Center for Community and Global Engagement. The program, which is a collaboration between Alvernia faculty, staff and students with the Reading School District, provides annual summer camps, after-school mentoring during the academic year and a variety of cultural activities, including museum visits, sporting events and educational field trips all within the Greater Reading and Philadelphia area. Since the program began in 2006, the Reading Youth Initiative has provided enrichment and literacy services to more than 1,100 students.
"As a leading community bank, we have an obligation to not only provide financial services to businesses and individuals, but also to strengthen and support the health and livelihood of the communities in which we operate," said Richard Ehst, President and Chief Executive Officer of Customers Bank. "Helping students gain access to better educational opportunities and afterschool programs helps prepare them for continuing their education, so they are able to enter the workforce and provide meaningful contributions back to their communities."
Designed to enhance the established school curriculum, the Reading Youth Initiative offers elementary school students literacy training, homework assistance, academic enrichment activities and mentoring programs. The program serves students from Millmont Elementary School, Tyson-Schoener Elementary School and the St. Peter School, where the program first launched.
"Customers Bank is a valued partner and we are appreciative for their longstanding collaboration as the university continues to expand its mission-based academic and community initiatives," said Alvernia University President John R. Loyack.
The funding from Customers Bank allows Alvernia to expand services to children during the school year and in the summer and hire professional staff for ongoing support, thus increasing the program's scale and quality. Customers Bank is funding the Alvernia initiative as part of the Pennsylvania Educational Improvement Tax Credit Program.
"Alvernia University and the Holleran Center continue to be so very appreciative of the generous support that we receive from Customers Bank," stated Dr. Rudy Ruth, Executive Director for The Holleran Center for Community and Global Engagement. "Customers Bank's continued support affords Alvernia the opportunity to partner with the Reading School District through impactful student focused programming."


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SceneView memory resources
The amount of memory available in the SceneView to display features and terrain depends on a number of factors, such as the device, but also the specified qualityProfile. In complex scenes the SceneView may reach this memory limit. To prevent browser crashes and slow performance, it will reduce the amount of data rendered. This sample shows how to use SceneView.performanceInfo to get information about memory consumption in a scene. Such information can be useful to scene creators and application developers working with webscenes.
PerformanceInfo.usedMemory shows an estimation of how much memory the SceneView is currently using. When this value approaches the totalMemory, then the Quality is reduced. This will reduce the level of detail for scene layers, lower the tile resolution for tiled layers, and reduce the number of features for feature layers.
SceneView.performanceInfo.layerPerformanceInfos contains information about memory consumption for each of the layers in the scene. displayedNumberOfFeatures gives information about how many features are currently displayed in the view. The property maximumNumberOfFeatures shows how many features could be displayed in the SceneView. The maximumNumberOfFeatures property available on FeatureLayer, CSVLayer, GeoJSONLayer and point SceneLayer can be used to override the default value and display more features even if there isn't enough memory. High values could however lead to the browser running out of memory.


text:
Help with complex program
I am in need of a program. I am not sure how to program such a thing, so I'll ask for help. :p
1. I need to make this program calculate the total number of possible combinations of letters and/or numbers in an entered amount of digits. (example: entered 1 digit for numbers only and you get: 10. Enter two digits for numbers only and get: 100. ect.) There must be some sort of formula, but I am not sure what it is.
2. Is is possible with C++ to have this program make the mouse click at specified x,y and to have the program type in text and deleate text? If so, then how would I go about doing this? If no, then what language could accomplish this?


Wonder and Inspiration Delivered — Since 1942
Floating Ball Game
(Click image to enlarge)
Item Number: _PHONE_
Price: $3.00
This item is available for giftwrap!
Game, Floating Ball
Floating Ball Game - Demonstrates Bernoulli's Principle - Law of Pressure Differential
Another classic science toy that is not only fun but teaches real scientific concepts. Made of wood. Comes with two styrofoam balls. See how long you can make the ball float. Challenge family and friends. Great party favor or holiday gift.
The floating ball game is an excellent example of "Bernoulli's Principle". As air is forced around the ball it must move faster in order to "catch up" on the other side. The result is a decrease in air pressure around the ball that in turn keeps the ball in place. The force is strong enough to resist other forces acting on the ball such as a subtle tap from your finger. The force can also overcome gravity if the flow of air is strong enough. This can be demonstrated by turning the base of the pipe 15-20 degrees - the ball will remain suspended in the air flow even though it is not directly above it.
Give it a try and see what you can discover!
Warning: Choking Hazard -Small Parts. Not for children under 3 years. /!\ Warning: Choking Hazard -This toy is a small ball. Not for children under 3 years.
SKU _PHONE_
Related Products


Roman Republic, Semuncia
This Roman semuncia shows the head of Bellona, the goddess of war, on the obverse. The reverse depicts the typical motif on Roman bronze coins, the prora, a prow.
When the coin was issued, Rome was just waging the Second Punic War (218-201 BC) against the Carthaginians, whom the Romans also called Punici. The two parties had already fought a long and bloody war some decades earlier, the First Punic War (264-241 BC). It would take yet another war, the Third Punic War (149-146 BC), to settle the power balance in the Mediterranean once and for all. The Roman Republic would remain victorious, the Carthaginian state would perish.
Signet Sunflower Foundation


two dice, for example, we get $$ (2-7)^2{1\over 36} + (3-7)^2{2\over 36} + \cdots + (7-7)^2{6\over 36} +\cdots (11-7)^2{2\over36} + (12-7)^2{1\over36} = {35\over36}. $$ Because we squared the differences this does not directly measure the typical distance we seek; if we take the square root of this we do get such a measure, \($\sqrt{35/36}\approx 2.42\). Doing the computation for the strange 11-sided die we get $$ (2-7)^2{1\over 11} + (3-7)^2{1\over 11} + \cdots + (7-7)^2{1\over 11} +\cdots (11-7)^2{1\over11} + (12-7)^2{1\over11} = 10, $$ with square root approximately 3.16. Comparing 2.42 to 3.16 tells us that the two-dice rolls clump somewhat more closely near 7 than the rolls of the weird die, which of course we already knew because these examples are quite simple.
To perform the same computation for a probability density function the sum is replaced by an integral, just as in the computation of the mean. The expected value of the squared distances is $$V(X)= \int_{-\infty }^\infty (x-\mu)^2 f(x)\,dx,$$ called the variance. The square root of the variance is the standard deviation, denoted \(\sigma\).
Example \(\PageIndex{6}\)
We compute the standard deviation of the standard normal distrubution. The variance is $${1\over\sqrt{2\pi}}\int_{-\infty}^\infty x^2 e^{-x^2/2}\,dx.$$ To compute the antiderivative, use integration by parts, with \(u=x\) and \(dv=xe^{-x^2/2}\,dx\). This gives $$\int x^2 e^{-x^2/2}\,dx = -x e^{-x^2/2}+\int e^{-x^2/2}\,dx.$$ We cannot do the new integral, but we know its value when the limits are \(-\infty\) to \(\infty\), from our discussion of the standard normal distribution. Thus $$ {1\over\sqrt{2\pi}}\int_{-\infty}^\infty x^2 e^{-x^2/2}\,dx= \left.-{1\over\sqrt{2\pi}}x e^{-x^2/2}\right|_{-\infty}^\infty + {1\over\sqrt{2\pi}}\int_{-\infty}^\infty e^{-x^2/2}\,dx= 0+{1\over\sqrt{2\pi}}\sqrt{2\pi}=1. $$ The standard deviation is then \(\sqrt{1}=1\).
Here is a simple example showing how these ideas can be useful. Suppose it is known that, in the long run, 1 out of every 100 computer memory chips produced by a certain manufacturing plant is defective when the manufacturing process is running correctly. Suppose 1000 chips are selected at random and 15 of them are defective. This is more than the 'expected' number (10), but is it so many that we should suspect that something has gone wrong in the manufacturing process? We are interested in the probability that various numbers of defective chips arise; the probability distribution is discrete: there can only be a whole number of defective chips. But (under reasonable assumptions) the distribution is very close to a normal distribution, namely this one:
$$ f(x)={1\over\sqrt{2\pi}\sqrt{1000(.01)(.99)}} \exp\left({-(x-10)^2\over 2(1000)(.01)(.99)}\right), $$
which is pictured in Figure \(\PageIndex{3}\) (recall that \(\exp(x)=e^x\)).
Normal density function for the defective chips example.
Figure \(\PageIndex{3}\). Normal density function for the defective chips example.
Now how do we measure how unlikely it is that under normal circumstances we would see 15 defective chips? We can't compute the probability of exactly 15 defective chips, as this would be \(\int_{15}^{15} f(x)\,dx = 0\). We could compute \(\int_{14.5}^{15.5} f(x)\,dx \approx 0.036\); this means there is only a \(3.6%\) chance that the number of defective chips is 15. (We cannot compute these integrals exactly; computer software has been used to approximate the integral values in this discussion.) But this is misleading: \(\int_{9.5}^{10.5} f(x)\,dx \approx 0.126\), which is larger, certainly, but still small, even for the "most likely'' outcome. The most useful question, in most circumstances, is this: how likely is it that the number of defective chips is "far from'' the mean? For example, how likely, or unlikely, is it that the number of defective chips is different by 5 or more from the expected value of 10? This is the probability that the number of defective chips is less than 5 or larger than 15, namely
$$ \int_{-\infty}^{5} f(x)\,dx + \int_{15}^{\infty} f(x)\,dx \approx 0.11. $$
So there is an \(11%\) chance that this happens---not large, but not tiny. Hence the 15 defective chips does not appear to be cause for alarm: about one time in nine we would expect to see the number of defective chips 5 or more away from the expected 10. How about 20? Here we compute $$ \int_{-\infty}^{0} f(x)\,dx + \int_{20}^{\infty} f(x)\,dx \approx 0.0015. $$ So there is only a \(0.15%\) chance that the number of defective chips is more than 10 away from the mean; this would typically be interpreted as too suspicious to ignore---it shouldn't happen if the process is running normally.
The big question, of course, is what level of improbability should trigger concern? It depends to some degree on the application, and in particular on the consequences of getting it wrong in one direction or the other. If we're wrong, do we lose a little money? A lot of money? Do people die? In general, the standard choices are 5% and 1%. So what we should do is find the number of defective chips that has only, let us say, a 1% chance of occurring under normal circumstances, and use that as the relevant number. In other words, we want to know when
$$ \int_{-\infty}^{10-r} f(x)\,dx + \int_{10+r}^{\infty} f(x)\,dx < 0.01. $$
A bit of trial and error shows that with \(r=8\) the value is about \(0.011\), and with \(r=9\) it is about \(0.004\), so if the number of defective chips is 19 or more, or 1 or fewer, we should look for problems. If the number is high, we worry that the manufacturing process has a problem, or conceivably that the process that tests for defective chips is not working correctly and is flagging good chips as defective. If the number is too low, we suspect that the testing procedure is broken, and is not detecting defective chips.
Contributors
David Guichard (Whitman College)
 - Integrated by Justin Marshall.


text:
Rope – la cuerda
To remember that rope is pronounced kwehr-dah (cuerda) in Spanish, use the following mnemonic:
The rope shows he must have climbed out the window. The question is, where has Dad gone?
Cuerda is feminine, so it's la cuerda. Imagine a lady swinging on a rope.


Performance Testing Framework with Gatling and Maven
What is the best way to organize and structure a Gatling project for performance testing?
When designing a framework, we should think about maintainability and extendability, thus how we organize the components is very important.
In this tutorial, we will show how to create a performance testing framework from scratch using Gatling and maven.
Gatling Maven Test Framework
Pre-requisites:
For this tutorial you need to have the following installed:
 - Java 1.8
 - Maven 3.5
 - IntelliJ with Scala Plugin installed
First, we create a base project by running the maven Gatling archetype:
mvn archetype:generate -DarchetypeGroupId=io.gatling.highcharts -DarchetypeArtifactId=gatling-highcharts-maven-archetype
When you execute the above command, it will start downloading the dependencies.
When prompted, provide values for 'groupId', 'artifactId', and 'version'.
My setup looks like the following:
When you open the project, you will notice there are some default files and folders.
Under the resources, we have
bodies this package holds the request payloads. For example, you can have requests templates for various requests.
data this package holds the data you need to feed to your tests, such as CSVs.
In addition to the above two folders, there are Gatling.conf, logback.xml and recorder.conf files. We won't be discussing these in this tutorial.
The Gatling maven archetype also creates three base Scala object, but we won't be using them, so go ahead and delete the objects.
In addition, we will create four packages, config, requests, scenarios, and simulations:
Config Package
In the config package, create a Scala object called Config. This will hold various configurations for our project such as application URLs, default users, etc…
package io.devqa.config
object Config {
 val app_url = "_URL_"
 val users = Integer.getInteger("users", 10).toInt
 val rampUp = Integer.getInteger("rampup", 1).toInt
 val throughput = Integer.getInteger("throughput", 100).toInt
}
Requests Package
The requests package holds different operation requests. For example, we could have a request that gets an authorization token. Another request can use the token from the previous request to create a user and so on.
These are individual and isolated requests sent to different endpoints.
GetTokenRequest
package io.devqa.requests
import io.gatling.core.Predef._
import io.gatling.http.Predef._
import io.devqa.config.Config.app_url
object GetTokenRequest {
 val get_token = http("RequestName").get(app_url + "/token")
 .check(status is 200)
 .check(jsonPath("$..token").saveAs("token"))
}
CreateUserRequest
package io.devqa.requests
import io.devqa.config.Config.app_url
import io.gatling.core.Predef._
import io.gatling.http.Predef._
object CreateUserRequest {
 val sentHeaders = Map("Authorization" -> "bearer ${token}")
 val create_user = exec(http("Create User Request")
 .post(app_url + "/users")
 .headers(sentHeaders)
 .formParam("name", "John")
 .formParam("password", "John5P4ss")
 .check(status is 201)
 .check(regex("Created").exists))
}
Scenarios Package
The scenario package holds the business scenarios. For example, to create a user, we first have to get an auth token and then send the token as a header along with form parameters to create a user. i.e. we use the response of the first request to feed to the second request. This "chaining of requests" is quite common in API testing.
CreateUserScenario
package io.devqa.scenarios
import io.devqa.requests.{CreateUserRequest, GetTokenRequest}
import io.gatling.core.Predef.scenario
object CreateUserScenario {
 val createUserScenario = scenario("Create User Scenario")
 .exec(GetTokenRequest.get_token)
 .exec(CreateUserRequest.create_user)
}
Simulations Package
Finally, we have the Simulations in the simulations package. You can think of simulations as different load profiles. For example, we can have a normal load simulation or a spike simulation.
The simulations need to be Scala classes and they must extend the Gatling Simulation class.
package io.devqa.simulations
import io.devqa.scenarios.CreateUserScenario
import io.gatling.core.Predef.Simulation
import io.gatling.core.Predef._
import io.devqa.config.Config._
class CreateUserSimulation extends Simulation {
 private val createUserExec = CreateUserScenario.createUserScenario
 .inject(atOnceUsers(users))
 setUp(createUserExec)
}
Your project should look like the following:
We also need to modify our pom.xml file to be able to pass parameters, such as users and throughput to our performance tests at runtime.
pom.xml file
The pom.xml file should look like:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="_URL_ xmlns:xsi="_URL_
 xsi:schemaLocation="_URL_ _URL_
 <modelVersion>4.0.0</modelVersion>
 <groupId>testing-excellence</groupId>
 <artifactId>gatling-framework</artifactId>
 <version>1.0-SNAPSHOT</version>
 <properties>
 <maven.compiler.source>1.8</maven.compiler.source>
 <maven.compiler.target>1.8</maven.compiler.target>
 <encoding>UTF-8</encoding>
 <gatling.version>2.3.0</gatling.version>
 <gatling-plugin.version>2.2.4</gatling-plugin.version>
 <typesafe-config.version>1.3.2</typesafe-config.version>
 <simulation>CreateUserSimulation</simulation>
 </properties>
 <dependencies>
 <dependency>
 <groupId>io.gatling.highcharts</groupId>
 <artifactId>gatling-charts-highcharts</artifactId>
 <version>${gatling.version}</version>
 <scope>test</scope>
 </dependency>
 <dependency>
 <groupId>com.typesafe</groupId>
 <artifactId>config</artifactId>
 <version>${typesafe-config.version}</version>
 </dependency>
 </dependencies>
 <build>
 <plugins>
 <plugin>
 <groupId>io.gatling</groupId>
 <artifactId>gatling-maven-plugin</artifactId>
 <version>${gatling-plugin.version}</version>
 <configuration>
 <simulationClass>io.devqa.simulations.${simulation}</simulationClass>
 <jvmArgs>
 <jvmArg>-Denv=${env}</jvmArg>
 <jvmArg>-Dusers=${users}</jvmArg>
 <jvmArg>-Drampup=${rampup}</jvmArg>
 <jvmArg>-Dduration=${duration}</jvmArg>
 <jvmArg>-Dthroughput=${throughput}</jvmArg>
 </jvmArgs>
 <propagateSystemProperties>true</propagateSystemProperties>
 </configuration>
 </plugin>
 </plugins>
 </build>
</project>
Finally, to execute the simulation class, we run the following command
mvn clean gatling:execute -Dusers=1
The above command will run the CreateUserSimulation with 1 user.


text:
Carraízo Dam facts for kids
Quick facts for kidsCarraízo Dam
Carraízo Dam in 2007
Location of Carraízo Dam in Puerto Rico
|Official name||Carraízo Dam|
|Location||Trujillo Alto, Puerto Rico|
|Purpose||Water storage, recreation|
|Construction cost||$60 million|
|Owner(s)||Puerto Rico Aqueducts and Sewers Authority|
|Dam and spillways|
|Type of dam||Concrete gravity|
|Impounds||Río Grande de Loíza|
|Height||44 m (144 ft)|
|Length||210 m (690 ft)|
|Width (crest)||45 ft (14 m)|
|Width (base)||30 m (98 ft)|
|Dam volume||26,800,000 m3 (35,100,000 cu yd)|
Carraízo Dam is a concrete gravity dam located in the municipality of Trujillo Alto, Puerto Rico within the flow of the Río Grande de Loíza. Its construction was completed in 1953. Carraízo Dam impounds Loíza Lake which serves as Puerto Rico's main water reservoir.
Background and construction
At the end of the 1940s, the Puerto Rico Aqueducts and Sewers Authority (PRASA) proposed the construction of a dam at the Río Grande de Loíza in the Barrio Carraízo of Trujillo Alto with the intention of providing both water and electricity to the San Juan Metropolitan Area.
Construction of the dam began in 1950 and finished in 1954. As part of the construction, the dam included three hydroelectric turbines with a total capacity of 3 Megawatts for the provision of electricity. However, during the 1960s and 1970s, the turbines were shut down because their operation and maintenance wasn't considered cost-effective versus the cost of buying energy at the time.
In 1989 Hurricane Hugo caused overtopping of the dam, thereby flooding the hydroelectric facility and rendering it inoperable. It stayed closed until 2013, when PRASA elected to renovate the facility.
Carraízo dam is a concrete gravity dam. It features eight floodgates along its 210-meter body. The floodgates open at a height of 1 to 10 meters, but they are usually opened at 4 meters. The reservoir created by the Carraízo Dam is the Loíza Lake. Carraízo's water storage capacity is of 4,650,000 gallons, and 41.15 meters is its peak level.
Carraízo Dam Facts for Kids. Kiddle Encyclopedia.


text:
Meet the new species of pit viper found in Arunachal Pradesh
Itanagar, May 10: India now has a fifth brown pit viper with a reddish tinge, a venomous snake with a unique heat-sensing system - from a forest in West Kameng district of Arunachal Pradesh.
The discovery, published in the March-April volume of the Russian Journal of Herpetology, makes the Arunachal pit viper (Trimeresurus arunachalensis) the second serpent to have been discovered after the non-venomous crying keelback in the State's Lepa-Rada district in 2018.
The new species also makes Arunachal Pradesh the only Indian state to have a pit viper named after it.
What does heat sensing ability means?
They have special pits located between their eyes and nostrils that can sense minute temperature changes as infrared rays, as an aid in locating warm-blooded prey such as rodents. Snakes use the radiation to generate 'thermal images' of predators or prey, but the underlying physiology has been unclear.
The more advanced infrared sense of pit vipers allows these animals to strike prey accurately even in the absence of light, and detect warm objects from several meters away.
It is found on the sensory nerve fibres that stimulate the snakes' pit organ, the highly specialised facial structure that initially detects radiant heat and consists of cavities located on each side of the head.
Also called 'heat vision', the infrared rays have longer wavelengths than those of visible light and signify the presence of warm-blooded prey in three dimensions which helps a snake aim its attack.
A pit has two chambers. The interior chamber is naturally the internal temperature of the snake itself. The exterior chamber heats up when it is close to a heat source.
The snake is then able to detect the temperature difference between the two chambers. This system is so accurate that pit vipers are actually able to detect temperature changes as little as 0.002 degrees centigrade.
Types of snakes with pits
As snakes evolved, they branched out into vipers and constrictors. The vipers further evolved to include pit vipers (part of the scientific sub-family in Viperidae called Crotalinae). Not all vipers have pits, and not all boa constrictors and pythons do either. Pit vipers are found worldwide and are all poisonous, just as all vipers are poisonous.
India had four brown pit vipers - Malabar, Horseshoe, Hump-nosed and Himalayan - before the Arunachal Pradesh discovery.
Other uses of the pits
Snakes also use pit organs to help them find cool places to regulate their internal temperatures. Snakes are reptiles and cold-blooded, which means they have to warm up in the sun. When they get too warm, they have to find a cooler area to use for bringing down their temperatures. The pits on their faces help them find these cool places. When the loreal pits are blocked or otherwise covered, the snake has trouble finding these places when needed, as if blind.


Temporal shifts in the pair-bond dynamics of New Zealand robins (Petroica australis)
Citation
Menzies, I. J., & Burns, K. (2010). Temporal shifts in the pair-bond dynamics of New Zealand robins (Petroica australis). New Zealand Journal of Ecology, 265–268.
Summary
Winter is a challenging time for temperate insectivorous songbirds, due to colder temperatures, reduced prey activity and shorter diurnal foraging times. For species that are non-migratory, territorial and monogamous, winter conditions may result in within-pair competition. However, little is known about how monogamous pairs coexist on their winter territories.
We investigated temporal patterns in male–female interactions of the New Zealand robin (Petroica australis) to better understand mechanisms of coexistence during winter. Previous work has shown that male robins are physically dominant over females and maintain priority access to food year-round. We quantified female behaviour throughout the 2008 non-breeding season to better understand how females coexist with physically dominant males on winter territories. Results showed that pairs rarely forage in close proximity in autumn and winter, suggesting females avoid males at this time of year. Males and females begin to spend more time foraging together as winter turns to spring. During this winter–spring transitional period, females steal large amounts of food hoarded by males. These results indicate that male and female New Zealand robins use different behavioural mechanisms to coexist on their winter territories. While males are dominant physically, females show a seasonally variable strategy where they avoid males in autumn and winter, and then steal male-made caches from early spring until the onset of inter-pair cooperation and the breeding season.


text: An EMG signal shows almost one-to-one relationship with the corresponding muscle. Therefore, each joint motion can be estimated relatively easily based on the EMG signals to control wearable robots. However, necessary EMG signals are not always able to be measured with every user. On the other hand, an EEG signal is one of the strongest candidates for the additional input signals to control wearable robots. Since the EEG signals are available with almost all people, an EEG based method can be applicable to many users. However, it is more difficult to estimate the user's motion intention based on the EEG signals compared with the EMG signals. In this paper, a user's motion estimation method is proposed to control the wearable robots based on the user's motion intention. In the proposed method, the motion intention of the user is estimated based on the user's EMG and EEG signals. The EMG signals are used as main input signals because the EMG signals have higher correlation with the motion. Furthermore, the EEG signals are used to estimate the part of the motion which is not able to be estimated based on EMG signals because of the muscle unavailability.


Advertisement
Forensic Toxicology
, 26:23 | Cite as
Determination of fluoride in human whole blood and urine by gas chromatography-mass spectrometry
 - Shigetoshi Kage
 - Keiko Kudo
 - Naoki Nishida
 - Hideaki Ikeda
 - Naofumi Yoshioka
 - Noriaki IkedaEmail author
Short Communication
Abstract
We developed a simple and sensitive method for determination of fluoride in human whole blood and urine using gas chromatography-mass spectrometry (GC-MS). Fluoride was alkylated with pentafluorobenzyl bromide in a mixture of acetone and phosphate buffer (pH 6.8). The derivative obtained was analyzed by GC-MS in the positive-ion electron-impact mode. The lower limit of detection for the compound was 0.5 mg/l for both matrices. The calibration curve for fluoride was linear over the concentration range of 1–100 mg/l. The precision and accuracy of the method were evaluated, and relative standard deviation was within 10%. Using this method, levels of fluoride in whole blood and urine were determined in a case of poisoning caused by hydrofluoric acid exposure.
Keywords
Fluoride Hydrofluoric acid Gas poisoning GC-MS Pentafluorobenzyl Whole blood
References
 1. 1.
 Mayer TG, Gross PL (1985) Fatal systemic fluorosis due to hydrofluoric acid burns. Ann Emerg Med 14:149–153PubMedCrossRefGoogle Scholar
 2. 2.
 McIvor ME (1987) Delayed fatal hyperkalemia in a patient with acute fluoride intoxication. Ann Emerg Med 16:1165–1167PubMedCrossRefGoogle Scholar
 3. 3.
 Muriale L, Lee E, Genovese J, Trend S (1996) Fatality due to acute fluoride poisoning following dermal contact with hydrofluoric acid in a palynology laboratory. Ann Occup Hyg 40:705–710PubMedGoogle Scholar
 4. 4.
 Kono K, Watanabe T, Dote T, Usuda K, Nishiura H, Tagawa T, Tominaga M, Higuchi Y, Onnda M (2000) Successful treatments of lung injury and skin burn due to hydrofluoric acid exposure. Int Arch Occup Environ Health 73(Suppl):S93–S97PubMedCrossRefGoogle Scholar
 5. 5.
 Takase I, Kono K, Tamura A, Nishino H, Dote T, Suzuki K (2004) Fatality due to acute fluoride poisoning in the workplace. Legal Med 6:197–200PubMedCrossRefGoogle Scholar
 6. 6.
 Stremski ES, Grande GA, Ling LJ (1992) Survival following hydrofluoric acid ingestion. Ann Emerg Med 21:1396–1399PubMedCrossRefGoogle Scholar
 7. 7.
 Bost RO, Springfield A (1995) Fatal hydrofluoric acid ingestion: a suicide case report. J Anal Toxicol 19:535–536PubMedGoogle Scholar
 8. 8.
 Cordero SC, Goodhue WW, Splichal EM, Kalasinsky VF (2004) A fatality due to ingestion of hydrofluoric acid. J Anal Toxicol 28:211–213PubMedGoogle Scholar
 9. 9.
 Arnow PM, Bland LA, Garcia-Houchins S, Fridkin S, Fellner SK (1994) An outbreak of fatal fluoride intoxication in a longterm hemodialysis unit. Ann Intern Med 121:339–344PubMedGoogle Scholar
 10. 10.
 Vogt RL, Witherell L, LaRue D, Klaucke DN (1982) Acute fluoride poisoning associated with an on-site fluoridator in a Vermont elementary school. Am J Public Health 72:1168–1169PubMedCrossRefGoogle Scholar
 11. 11.
 Gessner BD, Beller M, Middaugh JP, Whitford GM (1994) Acute fluoride poisoning from a public water system. N Engl J Med 330:95–99PubMedCrossRefGoogle Scholar
 12. 12.
 Poklis A, Mackell MA (1989) Disposition of fluoride in a fatal case of unsuspected sodium fluoride poisoning. Forensic Sci Int 41:55–59PubMedCrossRefGoogle Scholar
 13. 13.
 Monsour PA, Kruger BJ, Petrie AF, McNee JL (1984) Acute fluoride poisoning after ingestion of sodium fluoride tablets. Med J Aust 141:503–505PubMedGoogle Scholar
 14. 14.
 Whitford GM (1992) Acute and chronic fluoride toxicity. J Dent Res 71:1249–1254PubMedGoogle Scholar
 15. 15.
 Hui D-M, Minami M (2000) Monitoring of fluorine in urine samples of patients involved in the Tokyo sarin disaster, in connection with the detection of other decomposition products of sarin and the by-products generated during sarin synthesis. Clin Chim Acta 302:171–188PubMedCrossRefGoogle Scholar
 16. 16.
 Hall RJ (1963) The spectrophotometric determination of submicrogram amounts of fluorine in biological specimens. Analyst 88:76–83CrossRefGoogle Scholar
 17. 17.
 Speaker JH (1976) Determination of fluoride by specific ion electrode and report of a fatal case of fluoride poisoning. J Forensic Sci 21:121–126PubMedGoogle Scholar
 18. 18.
 Nedeljković M, Antonijević B, Matović V (1991) Simplified sample preparation for fluoride determination in biological materials. Analyst 116:477–478PubMedCrossRefGoogle Scholar
 19. 19.
 Small H, Stevens TS, Bauman WC (1975) Novel ion exchange chromatographic method using conductimetric detection. Anal Chem 47:1801–1809CrossRefGoogle Scholar
 20. 20.
 Belisle J, Hagen DF (1978) Method for the determination of the total fluorine content of whole blood, serum/plasma, and other biological samples. Anal Biochem 87:545–555PubMedCrossRefGoogle Scholar
 21. 21.
 Wildman BJ, Jackson PE, Jones WR, Alden PG (1991) Analysis of anion constituents of urine by inorganic capillary electrophoresis. J Chromatogr 546:459–466PubMedCrossRefGoogle Scholar
 22. 22.
 Ferslew KE, Hagardorn AN, Robert TA (2001) Capillary ion electrophoresis of endogenous anions and anionic adulterants in human urine. J Forensic Sci 46:615–626PubMedGoogle Scholar
 23. 23.
 Kage S, Kudo K, Ikeda H, Ikeda N (2004) Simultaneous determination of formate and acetate in whole blood and urine from humans using gas chromatography-mass spectrometry. J Chromatogr B 805:113–117CrossRefGoogle Scholar
 24. 24.
 Kage S, Kudo K, Ikeda H, Tsujita A, Ikeda N (2005) Determination of bromide in whole blood and urine from humans using gas chromatography-mass spectrometry. J Chromatogr B 817:335–339CrossRefGoogle Scholar
 25. 25.
 Sakayanagi M, Yamada Y, Sakabe C, Watanabe K, Harigaya Y (2006) Identification of inorganic anions by gas chromatography/mass spectrometry. Forensic Sci Int 157:134–143PubMedCrossRefGoogle Scholar
Copyright information
© Japanese Association of Forensic Toxicology 2008
Authors and Affiliations
 - Shigetoshi Kage
 - 1
 - Keiko Kudo
 - 2
 - Naoki Nishida
 - 3
 - Hideaki Ikeda
 - 1
 - Naofumi Yoshioka
 - 4
 - Noriaki Ikeda
 - 2
 Email author
 1. 1.Forensic Science LaboratoryFukuoka Prefectural Police HeadquartersFukuokaJapan
 2. 2.Department of Forensic Pathology and Sciences, Graduate School of Medical SciencesKyushu UniversityHigashi-ku, FukuokaJapan
 3. 3.Department of Legal Medicine, Graduate School of Medicine and Pharmaceutical SciencesUniversity of ToyamaToyamaJapan
 4. 4.Division of Forensic Sciences, Department of Social MedicineAkita University School of MedicineAkitaJapan
Personalised recommendations


text:
brick. When it comes to building materials, solid brick is obviously more expensive than brick veneer. For materials alone, you're looking at spending between $6 and $15 per square foot. Installation must be done by a professional mason. So, for both materials and labor, solid brick costs $14 to $30.
The masonry work required contributes to the higher cost for solid brick siding. However, your home will benefit from increased strength, longevity, and a timeless look.
How Can You Tell the Difference Between Solid Brick and Brick Veneer?
The easiest way to tell if your home has brick veneer or solid masonry construction is to take a look at the brick pattern. A brick veneer wall is a single wall, whereas a structural brick wall is two brick walls constructed side-by-side. To attach these two individual walls, masons install header rows. A header row is a layer of bricks that is installed perpendicular to the wall, which bridges the gap between the walls and makes the brick part of both walls.
Header bricks are rotated 90 degrees, installed with the short end facing outwards. If you know what you're looking for, this shift in the pattern is very apparent. While the specific pattern may vary, you typically see a header row roughly every six rows, or so.
Stone Veneer Siding
Stone veneer siding is the same concept as brick veneer but it's a cheap alternative to stone walls. It costs and an average of $6-$11 per square foot to install stone veneer siding, but it varies based on labor and materials. Homeowners spend between $9,000 and $18,000 to install stone veneer siding for their exterior walls.
The Stone veneer is made of one layer of thin stone on the outside that helps insulate your home. It is also more durable than traditional siding and can withstand impact quite well. Some stone veneer contains no stone and instead has a synthetic stone façade.
Synthetic stone veneer isn't as durable as standard stone veneer, and it doesn't insulate your home well. Either way, stone veneer siding is lightweight, visually appealing, and affordable to install compared to regular stone. Your final price depends on whether you choose stone, stone veneer, or fake stone siding for your exterior walls.
Stone walls are exorbitantly expensive to install, and they cost between $30 and $50 per square foot. It is the most expensive option for exterior walls, and stone walls cost $55,000-$70,000 or more to install. That limits who can choose stone for their walls, but it is such a desirable aesthetic that carries many benefits.
Authentic stone can naturally insulate your house better than any other material, but it comes at a cost. Stone is heavy and difficult to install which adds a lot of money in labor and material costs. Traditional stone walls include two thick layers of stone, and that requires plenty of stone to build up.
Stone walls are sensitive to the weather and moisture in the air, and they don't always hold up well. Time, weathering, and humidity can crack the surface of exterior stone walls and it's easy to notice. That alone makes veneer and fake stone siding a great alternative to authentic stone.
Your average professional contractor will charge you $6-$11 per square foot to install stone veneer siding. A stone veneer generally comes in panels that contractors install over a frame and secure with adhesive. That makes it fairly easy for professionals to install stone veneers which can keep labor costs to a minimum.
It takes up to 10 hours or more to install stone veneer if they already removed the old siding. A Stone veneer is better at retaining heat than a real stone in many cases, and that makes a veneer desirable. Many professionals install stone veneers over fiber cement, wood frames, or polyurethane panels for support. That also helps keep the construction costs low and helps insulate your house well.
Fake Stone Siding
Fake stone siding is similar to fake brick siding in that it can save hundreds or thousands of dollars. You can expect to pay between $4 and $9 per square foot to install the fake stone siding. Professionals install fake stone siding in strips and panels, and it is quite lightweight.
Fake stone siding is not great for insulation, and it doesn't look as authentic as natural stone. However, it is the cheapest stone or brick siding option besides fake brick siding, and it does look good. Choose fake stone siding if you want the desirable appearance of stone without the excessive installation cost.
|$30-$50 Per Square Foot
|$6-$11 Per Square Foot
|Fake Stone Siding
|$4-$9 Per Square Foot
Can Brick Veneer Be Repaired?
Yes, you can repair brick veneer when it succumbs to damage from water erosion and impact damage. Water damage is the most common problem with brick veneer exterior walls as moisture wears brick down. You must repair the brick veneer if there is visible damage so that water doesn't leak into the frame underneath the brick.
You can hire someone to fix your brick veneer and spend $100-$400 or more depending on the severity of the damage. Otherwise, you can prepare a mixture of mortar and apply it to the damaged parts of the brick veneer with a trowel. Simply wet the mortar for the next days after you apply it, and it will reinforce your brick veneer.
Does brick veneer require weep holes?
Yes, you need to put weep holes in your brick veneer walls so that water doesn't get trapped behind the wall. Otherwise, you run the risk of trapping water which can cause water damage and mold that can spread throughout the house. You need to make sure that your brick veneer wall has to weep holes in the mortar joints so that moisture has an escape route.
Should brick veneer be sealed?
Yes, you should always seal the brick veneer whether you install it indoors or outdoors. Professionals seal brick veneer walls with Thinset, caulk, and various construction adhesives. Seal your brick veneer wall to help protect it from erosion and other forms of moisture damage.
Does brick veneer add value?
Brick veneer siding does not add value in the way that solid brick walls add up to 8% value to a home. You can still possibly add more value with brick veneer than with vinyl siding, but it is not as sought after by buyers. However, it does help sell your home in the sense that brick veneer is visually appealing, and many prospective buyers enjoy the aesthetic.
Summing It Up
Brick veneer installation costs between $9,000 and $25,000 depending on what kind of veneer you choose. Face brick veneer and thin brick veneer are the most expensive options, but you can save money with a fake brick veneer. You may spend between $800 and $3,000 more if you have to remove old siding before you install a brick veneer.
Brick veneer installation takes 10 hours, and you may pay between $400 and $1,000 on labor depending on the rate. Expect to pay $100-$400 for any repairs that you need to make with damaged brick veneer walls. Brick veneer is an affordable, durable, visually appealing alternative to solid brick exterior walls.
Nick Durante is a professional writer with a primary focus on home improvement. When he is not writing about home improvement or taking on projects around the house, he likes to read and create art. He is always looking towards the newest trends in home improvement.
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