the completion of Q with
respect to [. [~. In precisely the same way, the field of p-adic numbers Qp is
the completion of Q with respect to [.[p. In particular, Q is dense in Qp
(with respect to [.[p) as well as in ~ (with respect to ]I+)-
A less abstract definition of a p-adic number, which can be shown to
be equivalent, is based on the following property: every p-adic number can
be written in a unique way as a power series
x= ~ xjp J (2.4)
where e e 2~ is again called the ordinal of x and where the xj (called the
digits) take integer values
O<,xj<~p-1, 0<x~p-1 (2.5)
The series (2.4) always converges (with respect to [.[p) and provides
us with a very concrete realization of Qp. Note that it is unique, while in
the case of ~, ambiguities are possible: 1 and 0.999... define the same real
number.
It is important to realize that while the absolute value [-[+, when
extended from Q to N, can take any positive (real) value, the p-adic norm
[.[p even when extended from Q to Qp keeps on taking a discrete set of
values, namely powers of p. It follows that many elements of Qp have the
p-Adic Dynamics 897
same norm. For example, there are an infinite number of "units" (i.e.,
numbers of norm IXlp= 1) given by
x = Xo + ~ x:p j (2.6)
j=l
where the digit x o is different from zero.
There is no ordering among p-adic numbers with the same norm. In
this respect Qp is similar to the complex numbers C. The relevance of this
remark comes from the fact that it is the ordered character of N which lies
at the heart of, e.g., Sarkovskii's theorem. ~
The Qp's and ~ are all distinct number fields. For example, + i and
+x/'6 belong to Qs but + x / ~ does not! What these assertions precisely
mean is that the equations x 2 - 6 = 0 and x ~ + 1 = 0 do admit solutions on
Qs while x 2 - 5 = 0 does not! More generally, one can show, as a con-
sequence of Hensel's lemma, (3'4) that for any p-adic number aeQp, its
square root ~ will belong to Qp (p >>.3) if a has an even ordinal and if its
first digit is a square modulo p!
The non-Archimedean nature of the p-adic norm has of course far-
reaching consequences. First of all, it implies what is usually called
"ultrametricity": any "triangle" with "sides" x, y, and x - y is necessarily,
isosceles, i.e., if, say, [Xlp < lylp, then I x - Y l p = [Ylp! It follows that Qp is
a disconnected field: subsets of Qp have no boundaries, or, more precisely,
they are both open and closed with respect to the topology induced by l" [?.
For example, the so-called p-adie integers Yp = { x l x E Qp, ]Xlp ~< l } can
also be defined a s ~_p={XlX~Qp, ]Xlp<p}. This implies in particular
that a "large" p-adic number cannot be constructed as the sum of many
"small" ones or, in other words, that there is no "path" in Qp since the
"path" concept relies on the possibility of covering a big distance in many
small steps. These consequences of the non-Archimedean nature of the
p-adic norm are somewhat counterintuitive and take a while to get used
to. But there are also enormous simplifications that come with them. First,
approximations are much easier to control than on ~, since small errors do
not add up to give bigger ones. Similarly, the convergence of series is
significantly simpler to study o n Qp than on ~: the series Z a,q n will con-
verge o n Qp iff lim,~oo [anq"lp-+O.
It should be clear from the preceding remarks that all theorems of real
analysis which rely on the "connectedness" of ~ will have no p-adic
counterparts. In particular, there is no intermediate value or mean value
theorem and hence continuous functions from, say, Zp to 7/p will not
necessarily have a fixed point.
The field of complex numbers C is a "quadratic extension" of N. The
898 Thiran e t al.
field C has the rather remarkable properties of being complete [with
respect to the extended absolute value: la + bil ~ - - ( a 2 + be) ~/2] as well as
algebraically closed (every polynomial equation on C admits a solution in
C). For each Qp, there is also an algebraically closed and complete exten-
sion f2p, which is, however, considerably more complicated to construct
than C. We will have no use of s in this paper.
Despite all the differences between ~ and Qp we will show in the next
sections that simple nonlinear mappings on Qp present astonishing
similarities with similar mappings on N! If nothing else, this strongly
suggests that there are "characteristic features" of dynamical systems which
do not even depend on the number fields used to model them.
3. Q U A D R A T I C M A P P I N G S A N D CYCLES
Our main interest will be in quadratic mappings
x ~ g ( x ) = a 2 x 2 + al x + ao (3.1)
where x, a0, a~, a2 all belong to Qp and p i> 3. 4
Through a simple conjugacy, (3.1) can be brought to the canonical
form
x ~f(x) = x 2+ a (3.2)
Indeed, let T be the linear transformation on Qp,
T ( x ) = 2x + # (3.3)
and thus
T-X(x) = (x- #)/2 (3.4)
Choosing 2 = a2 and # = al/2, one easily obtains
( T g T - 1)(x) = x 2 + a (3.5)
with
a = aoa2 + a f t 2 - a~/4 (3.6)
More generally one has
Tg" = f " T (3.7)
4As is often the case in number theory, p = 2 is somewhat special and we prefer to ignore it.
p-Adic Dynamics 899
where g" denotes, as usual, the nth iteration of the map g. Conjugate maps
are of course equivalent (~) in the sense that they exhibit the same
dynamical properties such as cycles, fixed points, etc.
Let us consider the mapping (3.2) starting from some initial p-adic
number xi~. If la]p ~ 1, we have
If"(&~)lp ~< 1 if Ix~,lp ~< 1 (3.8)
and
If'~(xin)lp~ if Ixi~lp > 1 (3.9)
On the other hand, if [alp> t, starting with Ixffnl~> lal~ or IX~nlp< lal~
leads to
,lim If~(x~n)lp ~
If [X~n]p= lalp, the iterative process will not diverge if and only if there is a
"conspiracy" at each step such that
[~fq(Xin)] 2 -~ af p = laf 1/2 (3.10)
This is possible only if ~ belong to Qp.
In the following we will be concerned only with orbits
{x, f(x), f2(x) ..... f " ( x ) } which remain bounded when n ---, oo.
Fixed points of the map (3.2) are solutions o f f ( x ) - - x , i.e., they are
given by
1 + (1 - 4 a ) 1/2
x+_ = 2 (3.11)
where the square root may or may not exist in Qv depending on the values
of a and p. Clearly, if this square root does not exist in Qp, there is no fixed
point.
Similarly, ~12) points of primitive period 2 are solutions of
f2(x) - x -- 1 + ( - 3 -- 4a) 1/2
- - -0, i.e., x+ = (3.12)
f ( x ) -- x - 2
For higher-order cycles, of course, exact formulas do not exist, in general.
A cycle of order n, with f n ( f f ) = 2, is attractive if, for x close to if, f"(x) is
closer. For a smooth enough map, this is equivalent to [fn(s 1 and
since
f"(x


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 - The first of these forms of asthma is bronchopulmonary aspergillosis, a serious allergy to a common fungus which can grow inside the lungs.
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text:
Started by Admin 1
The emergency plug tool for electric vehicles (EVs) is a specialized tool used by emergency responders to safely and quickly disconnect the high-voltage electrical system in an EV in the event of an accident or other emergency situation.
The emergency plug tool is designed to be used with the emergency plug or service disconnect, which is a safety feature found in most EVs. The emergency plug tool is typically a specially designed wrench or pliers that are used to disconnect the plug from the vehicles high-voltage battery.
The tool is designed to provide emergency responders with a quick and easy way to disconnect the high-voltage electrical system, which is important because the high-voltage system in an EV can pose a serious risk of electrocution if it is not properly isolated and de-energized.
In addition to the emergency plug tool, many emergency responders also carry other specialized tools and equipment when responding to accidents involving EVs. For example, they may carry insulated gloves and boots to protect themselves from electrical shock, as well as special saws and cutting tools that are designed to safely cut through the high-strength materials used in EV construction.
Overall, the emergency plug tool is an essential component of any EV extrication kit, and is an important tool for ensuring the safety of both occupants and emergency responders in the event of an accident or other emergency involving an EV. It is important for emergency responders to receive proper training in the use of the emergency plug tool and other specialized tools and equipment used in EV extrication to ensure a safe and effective response to any emergency situation.

source: m-a-p/FineFineWeb


theme information section, click on the name next to "Made by".
A theme page with an arrow pointing at the author's name.
Tip #519
Make a smooth transition to Vivaldi by importing your favorite Extensions from other Chromium-based browsers.
To make your move from your old browser to Vivaldi smoother, you can import important data such as Bookmarks, Passwords, History, and, the latest addition, Extensions with just a few clicks.
To import Extensions:
 1. Make sure the browser you want to export from is closed.
 2. In Vivaldi, go to the Vivaldi menu > File > Import from Applications or Files.
 3. Select the Chromium-based browser.
 4. Click "Start Import".
 5. When the import has finished, click "Close"
 6. On the Extensions management page that opens, enable the extensions you want to use in Vivaldi by clicking the toggle button at the bottom right corner of each extension card.
Import dialog open in the Vivaldi browser with an arrow pointing to Extensions.
Tip #518
Move the active tab to a different Workspace using Command Chains.
You can find Keyboard Shortcuts for numerous actions in your Vivaldi browser and with Command Chains you can make many more. For example, you can create a chain for moving the active tab to a different Workspace and bind it to a Keyboard Shortcut and Mouse Gesture of your choice. You can also type the chain's name in Quick Commands and even add a custom button on one of the toolbars to execute the chain on click.
To create a command chain for moving the active tab to a different workspace:
 1. Go to Settings > Quick Commands > Command Chains.
 2. Click on "Add Command Chain".
 3. Give the new chain a name.
 4. Enter the following commands.
 Use the "Add Command" button in the top right corner of the first command to add the next one.
 - Focus Address Field
 - Delay (100)
 - Copy
 - Delay (1000)
 - Close Tab
 - Switch to Workspace #
 - New Tab
 - Delay (100)
 - Paste and Go
 5. Go to Settings > Keyboard > Workspaces and/or Settings > Mouse > New Gesture and find the chain you created.
 6. Give the new chain a shortcut.
 7. Go to a page you want to move and use the shortcut to test your new Command Chain.
 8. Create the chain for each Workspace you have.


← Quest for Fire Began Earlier Than Thought
Alan4discussion's Avatar Jump to comment 16 by Alan4discussion
Comment 8 by katy Cordeth
Isn't it quite probable that the first cooked food that early man ate on a regular basis would have been prepared by immersing raw meat into hot springs - boiling it rather than broiling it?
It is possible to use hots springs, but there are serious limitations.
1. They are often heavily contaminated with chemical minerals.
2. A flowing spring washes away the nutrients.
3. A small fixed pool cannot be cleaned after earlier meals.
4. Hot water is difficult to transport without modern containers, and cools rapidly.
Naturally occurring volcanic springs would have provided a much more reliable and permanent source of heat and wouldn't have required him to sit around twiddling his opposable thumbs waiting for a forest fire or a lightning strike to occur.
Where there are hot springs, there are usually volcanic sources of fire, which will start natural fires, and from which burning material can be moved to a safe distance.
On the link I give _USER_ they actually run a barbecue directly from the volcanic heat, without combustible material being used at all.
Sun, 08 Apr 2012 09:46:23 UTC | #933038


text:
When it comes to jewelry, earrings are a popular choice for women of all ages. They can be simple or extravagant, and they come in many different materials and styles. Silver and marcasite earrings are a classic and timeless option that can add elegance and sophistication to any outfit. In this article, we will explore the beauty of silver and marcasite earrings, their history, and why they remain a popular choice for women today.
Silver and Marcasite Earrings: A Fashionable and Timeless Accessory
What are Silver and Marcasite Earrings?
Silver and marcasite earrings are a type of jewelry made from sterling silver and marcasite stones. Marcasite is a naturally occurring mineral that has a bright, metallic luster and is often used in jewelry making. The stones are cut and polished to create small, glittering facets that catch the light and create a beautiful sparkle.
The History of Silver and Marcasite Earrings
Silver and marcasite jewelry has been popular for centuries, dating back to the Victorian era. During this time, jewelry makers used marcasite stones as a substitute for diamonds and other precious gems. This was because marcasite has a similar sparkle and luster to diamonds but is much more affordable. In the 1920s and 1930s, silver and marcasite jewelry became fashionable once again during the Art Deco period. This style of jewelry was characterized by geometric shapes, clean lines, and bold designs. Silver and marcasite earrings were a popular choice for women who wanted to make a statement with their jewelry.
Why Silver and Marcasite Earrings Remain Popular Today
Despite the fact that silver and marcasite earrings have been around for centuries, they remain a popular choice for women today. There are several reasons why:
One of the reasons why silver and marcasite earrings are so popular is because of their timeless beauty. They have a classic and elegant look that never goes out of style. Whether you are wearing a vintage outfit or a modern one, silver and marcasite earrings can add a touch of sophistication and glamour to your look.
Another reason why silver and marcasite earrings are so popular is that they are versatile. They can be worn with a wide range of outfits, from casual to formal. They can also be dressed up or down depending on the occasion.
Silver and marcasite earrings are much more affordable than other types of jewelry, such as diamonds or gold. This makes them accessible to a wider range of women who want to add some sparkle to their look without breaking the bank.
The Versatility of Silver and Marcasite Earrings
One of the greatest things about silver and marcasite earrings is their versatility. They come in a variety of styles, from simple studs to intricate drop earrings, and can be worn with almost any outfit. Whether you're dressing up for a formal event or simply adding some sparkle to your everyday look, there is a pair of silver and marcasite earrings that will fit the bill. Their timeless elegance also makes them a great gift for any occasion, from birthdays to anniversaries. With their affordable price point and wide range of styles, silver, and marcasite earrings are a jewelry staple that should have a place in every collection.
The Benefits of Choosing Silver and Marcasite Earrings
Choosing silver and marcasite earrings over other types of jewelry can offer a number of benefits. First, silver is a durable and long-lasting metal that can withstand daily wear and tear. It's also hypoallergenic, making it a great choice for those with sensitive skin. Additionally, marcasite is a relatively affordable gemstone, which means you can enjoy the beauty of fine jewelry without breaking the bank. Silver and marcasite earrings also offer a unique and vintage look that can add character to any outfit. Whether you're looking for a simple and understated pair or a statement piece, silver, and marcasite earrings are a great choice for anyone looking for beautiful and timeless jewelry.
How to Wear Silver and Marcasite Earrings
When it comes to wearing silver and marcasite earrings, there are a few tips to keep in mind. If you're wearing statement earrings, keep the rest of your jewelry simple to avoid an overly busy look. Silver and marcasite earrings pair well with black or navy clothing and can add a touch of elegance to casual outfits. For a more formal occasion, consider wearing a pair of drop earrings with a simple updo to draw attention to your earrings. When selecting a pair of silver and marcasite earrings, consider your face shape and hair color. For example, drop earrings can elongate a round face, while stud earrings can be a great choice for those with short hair or an angular face shape. With these tips in mind, you can confidently wear your silver and marcasite earrings and make a statement wherever you go.
How to Care for Silver and Marcasite Earrings
If you want your silver and marcasite earrings to last for years to come, it is important to take care of them properly. Here are some tips for caring for your earrings:
Store them properly
When you are not wearing your silver and marcasite earrings, store them in a jewelry box or a soft pouch to protect them from scratches and damage.
Clean them regularly
To keep your earrings looking their best, clean them regularly with a soft cloth and a mild cleaning solution. Avoid using harsh chemicals or abrasive materials that could damage the stones or the silver.
Avoid wearing them in water
Silver and marcasite earrings should not be worn in water, as this can cause the silver to tarnish and the stones to become dull.
Silver and marcasite earrings are a beautiful and timeless accessory that can add elegance and sophistication to any outfit. They have a rich history and remain a popular choice for women today because of their timeless beauty, versatility, and affordability. By properly caring for your silver and marcasite earrings, you can ensure that they remain a cherished accessory in your jewelry collection for years to come.


text:
high friction surface.
Lifting from underneath works because all the weight of the object sits on top. So long as the object doesn't topple to either side it will lift up just fine.
THE PROJECT – Explore different material properties using the jaws and a jar of jam
Now, experiment with different materials from around the house and attach hem onto the jaws and test them using something relatively heavy and shiny. I would suggest a jar of jam or something similar BUT make sure you put a towel down in case you drop the jam – you don't want to be responsible for cleaning that up!!
How would you modify the design to make it more like a fork lift truck that that it could reach under objects to lift them up?
- What material was the best and why?
- Were these materials difficult to attach to the jaws? if so why?
- Can you sort materials into two piles, high friction and low friction.? What do you notice about each of them?
Project 8 – Why Cardboard?
Literally my favourite material. Don't get me wrong, I've worked with titanium, die cast aluminium, stainless steel and a multitude of different types of plastics BUT the very best way to get kids interested in engineering is cardboard.
Why? The obvious question, and yet there are so many obvious answers. It's almost free! Every box and parcel delivered to your door, the cereal packets in your cupboards, the inside of your toilet rolls – they are literally giving you FREE materials to work with.
Not just that it's cheap, it's so incredibly versatile. I've created everything from gear systems, to full working cars, to masks, to ping pong ball launchers and visual models. Bend it one way it's super curvy, bend it the other way it becomes very strong. Together with 6 eight year olds, we've made a bridge that all their parents were able to walk over!
The tools required to work with cardboard are cheap, highly accessible and easy to use and with those tools you can create almost anything.
Here's a video I made a while ago showing the basics of cardboard…
Project 9 – The Tower of Hanoi
There's loads of parts to this challenge. The first thing to do is to build yourself some boxes. Below you'll find a link to a document to download and print. The document has plans to cut out and use to build the boxes AND it has the game sheet needed for the Tower of Hanoi Challenge. If you don't have a printer, you can draw the template from scratch like I did and you can draw out the game sheet too.
Once you've got your boxes made, it's time to play the game!
The challenge is to move the boxes from the pad at one end to the pad at the other end – sounds simple right? Well you need to do it in as few moves as possible AND you can only place a lower value box on top of a higher value box, oh and you can only move one box at a time. How many moves did you do it in?
Project 10- Digger Attachment
I've spent the last 8 years working in R&D. You have to work fast, efficient and economically to get answers as soon as possible. It's better to know that an idea won't work sooner rather than wasting weeks, months or years in development. The single best way I've seen over the years is to make our design modular. How can you get 10 answers out of one test rig? How can you design something that is adaptable where neither concept is compromised?
This project is learning to work with someone else's plans (Mine!). The design is already done BUT parts need to be made. It's about learning to make decent quality parts, the right way out of card then assemble them correctly so that the device works.
If it doesn't work the first time, that's ok. Have another go! I've given the kids a starting point by supplying the linkages laser cut in the main kit. these are the hardest parts to make. I've also added an extra dowel in the kit to use for the pivot points.
Watch the video then download the plans.

source: openbmb/Ultra-FineWeb


text:
(verb) deny or contradict (a fact or statement) "it was difficult to gainsay his claim"
(verb) speak against or oppose (someone) "none could gainsay her"
Gainsay meaning in Hindi (English to Hindi Dictionary)
विरोध करना, चुनौती देना, खण्डन करना, प्रतिवाद करना, अस्वीकार करना
- Middle English: from obsolete gain- 'against' + say.
Gainsay in a sentence (word usage in recent newspaper)
- "There is no gainsay from such statements," Mr. Diwan pointed out.
- "There is then no gainsay in the fact that transgenders enjoy basic human rights including protection from violence and discrimination.
- He was a perfectionist, but he will gainsay it for that's what invariably makes him a perfectionist.
- If these demanding practices help Muslims find peace and God, no one has a right to gainsay them.
- But he also makes points that officials struggle to gainsay.
Mnemonic trick to remember the meaning of gainsay
- gainsay = gain weight?? say it… don't deny… don't gainsay


[AMPL 24621] information about branch and bound with Gurobi in AMPL
Where i find the information about branch and bound in AMPL with solver Gurobi. In particulare these informations are : maximum cardinality Clique, dual bound release continuous , number of nodes branch and bound,
number of simplex iterations Time total of execution
For an introduction to mixed-integer programming and branch-and-bound using Gurobi, see _URL_ Concerning particular terms you mentioned, here are some definitions:
Maximum cardinality clique: See _URL_
"dual bound release continuous": It's not clear what you mean by this.
Number of nodes: Number of subproblems in the branch-and-bound search tree that have been explored by Gurobi's algorithm.
Number of simplex iterations: Total number of iterations of the simplex method that were needed to solve all subproblems in the search tree.
Total time of execution: Elapsed time for Gurobi's entire run; the clock time when Gurobi finished, minus the clock time when Gurobi started.


text:
What is "Android Backup"?
This backup option uses Google's "Auto Backup for Apps" to periodically create encrypted backups on Google Drive. The following data is saved:
- ID and key pair
- Contacts and verification levels
- Group memberships
- Contact and group images
- All settings
Please note that media files are not saved.
Backups are created about every 24 hours, provided the device is idle and connected to a Wi-Fi network and an external power source. The exact time is determined by the operating system based on various parameters. Threema can't initiate the backup process. In some cases, it can take several days until a backup is created. There is no way to manually trigger the backup process.
In the "Android Backup" tab, the status is "pending" until the first backup is created; then, date and time of the latest backup will be displayed. To get a list of all backups, open the Google Drive app and navigate to "[side drawer] > Backups > [device name] backup > Apps > Threema".
Backups are encrypted using NaCl and stored on Google Drive. It's not possible to store backups in a different location. Since the symmetric key is derived from the password, it's particularly important to choose a strong password. For more information about encryption, please consult the Cryptography Whitepaper.
If Android's "Automatic restore" is enabled (in "Settings > Backup & reset"), the latest backup will be automatically restored after the app was installed on a new device (or reinstalled on the current device), provided the same Google account is used. When opening the newly installed app, the user is prompted for the password, and once the correct password is entered, Threema restores the latest backup and restarts.
Differences between "Android Backup" and data backup
When using "Android Backup", backups will be created on a regular basis without any user interaction, whereas the creation of data backups must be manually triggered by the user. Hence, there is always a current backup available when using "Android Backup". This is a key advantage of "Android Backup" over data backups. Furthermore, app settings are included in "Android Backups" (but they are not included in data backups). On the other hand, data backups can include media files, while "Android Backups" don't include media files because Google limits the backup size to 25 MB per app and user.


(Untitled) (Untitled)(Untitled) (Untitled)(Untitled) (Untitled)(Untitled) (Untitled)(Untitled)Examples
IEVref:421-10-01ID:
Language:enStatus: Standard
Term: star connection
Synonym1: Y connection (US)
[Preferred]
Synonym2: wye connection (US)
[Preferred]
Synonym3:
Symbol:
Definition: the winding connection so arranged that one end of each of the phase windings of a polyphase transformer or reactor, or of each of the windings for the same rated voltage of single-phase transformers or reactors associated in a polyphase bank, is connected to a common point, i.e. the neutral point, and the other end to its appropriate line terminal
Publication date:1990-10
Source:
Replaces:
Internal notes:
CO remarks:
TC/SC remarks:
VT remarks:
Domain1:
Domain2:
Domain3:
Domain4:
Domain5:


What are the Risks of Yield Farming?
an image of a person holding a phone with crypto graphs and a laptop with the same - the Risks of Yield Farming
In several of our recent articles, we have discussed yield farming. I published the yield farming guide and then created a tutorial on how to do yield farming on Ubeswap. As explained in those articles, it is quite profitable. However, there are several risks of yield farming.
Any investment that offers medium to high rewards has risks, and yield farming is no different. That is why in this article, I will show you the risks of yield farming and liquidity mining so you are clear on what you're going into before you proceed.
If you don't know what yield farming is, click on any of the two links above to find out. I recommend you click on the first one and read through it before proceeding to the second.
What are the Risks of DeFi Yield Farming?
Here are the risks associated with yield farming:
 1. Risk of Impermanent Loss
 2. DeFi Smart Contract Risk
 3. Unfairness
 4. Risk of Scam
 5. Gas Fees
 6. Bugs in the Code
 7. Price Risks
 8. Strategy Risk
Risk of Impermanent Loss
Impermanent loss is one of the biggest risks of yield farming.
When farming yields on your assets, you add liquidity in pairs of equivalent value; if you add one ETH in an ETH/USDC pair and 1ETH is 2000 USDC, you must add 1ETH and 2000 USDC.
Suppose the value of ETH falls to 1000 USDC, the coins in the entire liquidity pool shifts to make up for that. When you have a huge loss in any of the coins in the pool in such situations, you can end up with an impermanent loss where you get a lower value than what you put in when you withdraw your liquidity.
The profit from farming yields on your cryptocurrency assets sometimes make up for the loss, but it doesn't always. Given the volatility of cryptocurrencies, you can be faced with this risk any time the value of a cryptocurrency drops. However, it only happens when the difference in value drops a lot.
DeFi Smart Contract Risk
Smart contracts control yield farming and DeFi. One bug in the smart contracts can cause the price of a token to drop to zero. A malicious hacker can exploit that bug to manipulate the project for any possibility, including losing all your cryptocurrency assets in the pools affected. To mitigate this risk, confirm that the smart contract has been audited.
Yield farming pools are controlled to a large extent by the founders and wealthier investors. That puts yield farmers with small funds at risk because if a wealthier investor takes out a large chunk of their investments, it can affect the platform.
One good example of this is what happened with Sushiswap. It fell quickly because the founder, Chef Nomi, removed his liquidity which ran in millions from the SUSHI/ETH pool. That caused a 73% crash in the price of SUSHI tokens which, of course, affected anyone holding the coin, including yield farmers.
Risk of Scam
When considering yield farming pools and applications to use, you need to be careful. Anyone can create an app for yield farming if they have the necessary skills. You must ensure that you are not using an app that isn't properly vetted or the owners aren't known.
Even then, you might still fall to this risk. The reason is that you get higher rewards from new protocols and applications; anyone that jumps on such in the first few weeks of launch can make a lot. When such things are new, you can't get reviews or comments from actual users.
You can still check online for comments because, in most cases, there would be some publicity about the app before they launch any liquidity pool. So, check GitHub, Twitter, and Reddit to see if there are negative comments.
Gas Fees
Gas fees on Ethereum are high – this is one fact that no one can debate. This is a problem for DeFi yield farming, especially for investors with smaller funds; wealthier participants might not mind.
When a lot of people take advantage of a yield farming opportunity and lock a lot of cryptocurrency in DeFi, gas fees skyrocket. In 2020, this was a big issue where gas fees reached over 100x more than usual due to yield farming activities on Uniswap.
When such happens, those with fewer funds would realize it's costly to withdraw their earnings and might end up losing money if they try. If they choose to leave the cryptocurrency in the pool, any other risks, such as impermanent loss and liquidation risks, can lead to a loss. Ethereum 2.0 with layer two scaling aims to solve this problem.
Bugs in the Code
Every app has bugs. Even when the developers do their best to ensure they don't, they can miss some of these things. For most top applications, such bugs don't cause much impact most of the time, but sometimes they can be serious. A malicious actor can exploit such issues to their advantage, making all investors in the yield farming pool lose their money.
Price Risks
This risk is not particular to farming yields on your cryptocurrency assets; it can happen to any crypto investor. As long as you hold crypto, you are liable to the risk of losing your money. Price changes happen a lot in the market. If the value of the coins in the pair you provide liquidity for lose value, you would lose some of your money,
There is also the aspect of the token. Some yield farming platforms offer their token as part of the rewards to yield farmers. If the value of the token falls, what you expect as returns for your investment reduces.
To give a clear picture of the above, here's this example. When farming yields on your assets in Ubeswap, you get UBE. If UBE was $5 when you invested but a few weeks later, it is $1, what you get in fiat is way different from what you expected at the time of your investment.
Strategy Risk
When doing yield farming, your strategy matters. You have to decide on what kind of pair to invest in. A hot pool today wouldn't be hot in a few weeks from now.
Here's the thing: if a pool provides 2000% returns which usually happens at launch, in a few weeks, that can drop to 300% because more money would have been pooled in by then. People would find out about that pool and invest, and as more people invest, the returns would reduce.
Although yield farming can be passive, you need to monitor your investment periodically, follow crypto news and us (subscribe for email updates), so you can pool out of a pool and invest in a better one when you need to.
You also look at the market's volatility as that can affect your capital and returns. If you weren't sure about a coin but invested only because of the high returns and the value is falling fast, you might decide to pool your investments in another pool.
Yield farming can be long term, so you shouldn't have to jump from pool to pool. Strategize wisely, and you will enjoy the returns from your crypto assets.
That is it for the risks associated with pulling your cryptocurrency in a yield farm. You can grow your cryptocurrency assets, whether Bitcoin, ethereum, Celo, and other cryptocurrencies in the blockchain. It's a great way to grow your cryptocurrency rather than leaving it to sit in an exchange or wallet.
I hope you take the suggestions in this article to mitigate your risks, so you earn more than you lose most of the time. Bear in mind that every good investment has risks; you just need to know how to mitigate them to reduce their impact.
If you have any questions or need help, click on this link for consulting with me. You can also subscribe using the form below to get updates whenever valuable posts like this are published.
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The Seven Cooperative Principles
TEC is built upon a foundation of timeless values
Cooperative business entities around the world adhere to the Seven Cooperative Principles originally formulated in the 1840s in England by the Rochdale weavers' cooperative. The principles have endured to this day and are a testament to the sustainability of the cooperative business model.
Democratic Member Control: Cooperatives are democratic organizations controlled by their members, who actively participate in setting policies and making decisions. The elected board of directors is accountable to the membership.
Members' Economic Participation: Members contribute equitably to, and democratically control, the capital of their cooperative. At least part of that capital is usually the common property of the cooperative. Members allocate surpluses for any or all of the following purposes: developing the cooperative; distributing capital credits according to co-ops' individual formulas; and supporting other activities approved by the members.
Concern for Community: While focusing on member needs, cooperatives work for the sustainable development of their communities through policies and activities accepted by their members.


text:
Nanoscale phase separation in the oxide layer at GeTe (111) surfaces†
As a semiconductor ferroelectric, GeTe has become a focus of renewed attention due to the recent discovery of giant Rashba splitting. It already has a wide range of applications, from thermoelectricity to data storage. Its stability in ambient air, as well as the structure and properties of an oxide layer, define the processing media for device production and operation. Here, we studied a reaction between the GeTe (111) surface and molecular oxygen for crystals having solely inversion domains. We evaluated the reaction kinetics both ex situ and in situ using NAP XPS. The structure of the oxide layer is extensively discussed, where, according to HAADF-STEM and STEM-EDX, nanoscale phase separation of GeO2 and Te is observed, which is unusual for semiconductors. We believe that such behaviour is closely related to the ferroelectric properties and the domain structure of GeTe.


text:
Water slide equipment can be broadly divided into two categories, one is the water park equipment
with tens of meters rise and hundreds of meters long slide large water slide; the other one is the kind of kindergarten used one with water playing function Water slide.
The former water slide equipment is for visitors to slide, the security, stability of the structure is very important. Water slide equipment is a large water park equipment in the water amusement facilities, belonging to the category of special equipment, grade B. Each set of equipment should go through the the inspection and testing of China Special Equipment Inspection Institute, and can be used after being issued the certificate. Most of the water slide equipment was installed in the outdoor, the natural environment has of great impact on the slide structure. Therefore, in the design stage of the water slide, the strength, stiffness, fatigue strength, stability, anti-overturning and anti-skid property of the structure must be calculation and analyzed, the safety factor of the corresponding specification should be prepared, and a formal calculation manual written. China's Special Equipment Inspection Institute issued the appropriate qualification of the engineers audit, then the identification report can be put into operation. The first set of equipment must be from the China Special Equipment Inspection Institute professional, with the appropriate qualification of engineers on-site inspection, issue type test report before use and mass production.
For the calculation and analysis of water slide equipment structure in the water park equipment, the permanent load, the live load, the wind load, the snow load, the seismic load and the impact load must be taken into account. Live load in the water slide equipment is generally the weight of the topic; live load only take their own load and water load; wind load is divided into working state load and non-working state load, recreational facilities design by the maximum operating wind speed 15m/s calculated the wind load and the non-working state is calculated according to the maximum wind load in 50 years. The snow load is calculated according to the maximum wind load in 50 years. When the seismic load is calculated, equivalent design on the base of eight degree, amount to the acceleration 0.2g calculation; calculation of impact load, the amusement facilities in the course of the movement may have an impact, it can not be accurately calculated when it is designing. Therefore, on the calculation of the strength, the permanent load and live load must be multiplied by the impact factor, according to its maximum speed of the water slide equipment, select the impact coefficient corresponding to the impact factor.
The water slide structure of water park equipment, including glass fiber reinforced plastic slide, steel structure, concrete foundation three parts. In view of the particularity, the importance and the complexity of the structure of the water slide, the finite element method is introduced into the analysis of the structure of the water slide, and the finite element method is applied to the various complex mechanisms in the water slide equipment, and has become an effective analytic method. After the introduction, it completely changed the traditional analysis method, the force analysis is more accurate, more comprehensive, more conducive for water slide structure check and design optimization.


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Source code: Lib/tokenize.py
The tokenize module provides a lexical scanner for Python source code, implemented in Python. The scanner in this module returns comments as tokens as well, making it useful for implementing "pretty-printers," including colorizers for on-screen displays.
To simplify token stream handling, all Operators and Delimiters tokens are returned using the generic token.OP token type. The exact type can be determined by checking the token string field on the named tuple returned from tokenize.tokenize() for the character sequence that identifies a specific operator token.
The primary entry point is a generator:
The tokenize() generator requires one argument, readline, which must be a callable object which provides the same interface as the io.IOBase.readline() method of file objects. Each call to the function should return one line of input as bytes.
The generator produces 5-tuples with these members: the token type; the token string; a 2-tuple (srow, scol) of ints specifying the row and column where the token begins in the source; a 2-tuple (erow, ecol) of ints specifying the row and column where the token ends in the source; and the line on which the token was found. The line passed (the last tuple item) is the logical line; continuation lines are included. The 5 tuple is returned as a named tuple with the field names: type string start end line.
Changed in version 3.1: Added support for named tuples.
Token value used to indicate a comment.
Token value used to indicate a non-terminating newline. The NEWLINE token indicates the end of a logical line of Python code; NL tokens are generated when a logical line of code is continued over multiple physical lines.
Token value that indicates the encoding used to decode the source bytes into text. The first token returned by tokenize() will always be an ENCODING token.
Another function is provided to reverse the tokenization process. This is useful for creating tools that tokenize a script, modify the token stream, and write back the modified script.
Converts tokens back into Python source code. The iterable must return sequences with at least two elements, the token type and the token string. Any additional sequence elements are ignored.
The reconstructed script is returned as a single string. The result is guaranteed to tokenize back to match the input so that the conversion is lossless and round-trips are assured. The guarantee applies only to the token type and token string as the spacing between tokens (column positions) may change.
It returns bytes, encoded using the ENCODING token, which is the first token sequence output by tokenize().
tokenize() needs to detect the encoding of source files it tokenizes. The function it uses to do this is available:
It will call readline a maximum of twice, and return the encoding used (as a string) and a list of any lines (not decoded from bytes) it has read in.
It detects the encoding from the presence of a UTF-8 BOM or an encoding cookie as specified in PEP 263. If both a BOM and a cookie are present, but disagree, a SyntaxError will be raised. Note that if the BOM is found, 'utf-8-sig' will be returned as an encoding.
If no encoding is specified, then the default of 'utf-8' will be returned.
Open a file in read only mode using the encoding detected by detect_encoding().
New in version 3.2.
Example of a script rewriter that transforms float literals into Decimal objects:
from tokenize import tokenize, untokenize, NUMBER, STRING, NAME, OP from io import BytesIO def decistmt(s): """Substitute Decimals for floats in a string of statements. >>> from decimal import Decimal >>> s = 'print(+21.3e-5*-.1234/81.7)' >>> decistmt(s) "print (+Decimal ('21.3e-5')*-Decimal ('.1234')/Decimal ('81.7'))" The format of the exponent is inherited from the platform C library. Known cases are "e-007" (Windows) and "e-07" (not Windows). Since we're only showing 12 digits, and the 13th isn't close to 5, the rest of the output should be platform-independent. >>> exec(s) _TAG_: +ELLIPSIS -3.21716034272e-0...7 Output from calculations with Decimal should be identical across all platforms. >>> exec(decistmt(s)) -3.217160342717258261933904529E-7 """ result = g = tokenize(BytesIO(s.encode('utf-8')).readline) # tokenize the string for toknum, tokval, _, _, _ in g: if toknum == NUMBER and '.' in tokval: # replace NUMBER tokens result.extend([ (NAME, 'Decimal'), (OP, '('), (STRING, repr(tokval)), (OP, ')') ]) else: result.append((toknum, tokval)) return untokenize(result).decode('utf-8')

source: HuggingFaceFW/fineweb-edu


text:
Available under a Creative Commons Attribution Non-Commercial Share Alike 4.0 International Licence
Public and environmental health, 3.3 HEALTH SCIENCES
Atmospheric cold plasma (ACP) is under investigation for an extensive range of biocontrol applications in food biosystems. However, the development of a novel intervention technology requires a thorough evaluation of the potential for negative effects and the implications for the human and animal food chains' safety. The evaluations were performed using a contained, high-voltage, dielectric barrier discharge plasma system. The cytotoxicity of two types of food models—a liquid model (wheat model medium (WMM)) vs. a solid model (wheat grain extract (WGE)) was compared in vitro using the mammalian cell line CHO-K1. The residual toxicity of ACP treatment of grains for food purposes was assessed using the invertebrate model Tribolium castaneum, by feeding the beetles with flour produced from ACP-treated wheat grains. The cytotoxic effects and changes in the chemistry of the ACP-treated samples were more pronounced in samples treated in a liquid form as opposed to actual wheat grains. The feeding trial using T. castaneum demonstrated no negative impacts on the survivability or weight profiles of insects. Investigations into the interactions of plasma-generated species with secondary metabolites in the food matrices are necessary to ensure the safety of plasma for food applications.
Bourke, P. et al (2020) Assessing the Biological Safety of Atmospheric Cold PlasmaTreated Wheat Using Cell and Insect Models,Foods, 9(7) DOI: 10.3390/foods9070898


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New Developments and Applications of Direct Dynamics Simulations for Gas Phase Reactions
MetadataShow full item record
Classical trajectories are propagated using the energy gradient calculated from quantum mechanical methods, through which atomic level chemical dynamics are used to investigate the properties of unimolecular and bimolecular reactions. The program development work involves the improvement of the interface between the classical trajectory simulation program (VENUS) and quantum chemical programs (NWChem and GAMESS) by adding trajectory restart capability and alternate initial SCF guesses. Intramolecular and intermolecular energy was followed along the trajectories to investigate energy partitioning and transferring, e.g., the partitioning between relative translational energy and internal (rotational and vibrational) energy to compare with molecular beam experiments, or the energy transfer between solvent and solute to investigate the solvent affect in chemical reaction. The simulations were performed on the chemical system of dissociation of 1,2-Dioxetian, F- + CH3I SN2 reaction, formation and dissociation of 1,5-Dinitrobiuret and spin-orbital coupling affect of HBr+ + CO2 reaction.


Rail profile
Rail profile
Rail from 1896
Cross-sections of flat-bottomed which can rest directly on the sleepers, and bullhead rails which sit in chairs (not shown).
The rail profile is the cross sectional shape of a railway rail,[1] perpendicular to the length of the rail.
In all but very early cast iron rails, a rail is hot rolled steel (once wrought iron) of a specific cross sectional profile (an asymmetrical I-beam) designed for use as the fundamental component of railway track.
Unlike some other uses of iron and steel, railway rails are subject to very high stresses and have to be made of very high quality steel. It took many decades to improve the quality of the materials, including the change from iron to steel. Minor flaws in the steel that pose no problems in reinforcing rods for buildings can, however, lead to broken rails and dangerous derailments when used on railway tracks.
By and large, the heavier the rails and the rest of the trackwork, the heavier and faster the trains these tracks can carry.
The rails represent a substantial fraction of the cost of a railway line. Only a small number of rail sizes are made by steelworks at one time, so a railway must choose the nearest suitable size. Worn, heavy rail from a mainline is often reclaimed and downgraded for re-use on a branchline, siding or yard.
Contents
Rail weights and sizes
Two commonly used rail profiles: a heavily worn 50 kg-profile and a new 60 kg-profile
The weight of a rail per length is an important factor in determining rails strength and hence axleloads and speeds.
Weights are measured in pounds per yard or kilograms per metre; the pounds-per-yard figure is almost exactly double the kilograms-per-metre figure. Rails in Canada, the United Kingdom and United States are still described using imperial units. In Australia, metric units are now used as in mainland Europe.
In rail terminology Pound is used synonymously with pounds per yard, e.g. a 132 pound rail means a rail of 132 lb/yd.
Europe
Rails are made in a large number of different sizes. Some common European rail sizes include:
 - 40 kg/m (80.6 lb/yd)
 - 50 kg/m (100.8 lb/yd)
 - 54 kg/m (108.9 lb/yd)
 - 56 kg/m (112.9 lb/yd)
 - 60 kg/m (121 lb/yd)
In the countries of former USSR 65 kg/m (131 lb/yd) rails and 75 kg/m (151.2 lb/yd) rails (not thermally hardened) are common. Thermally hardened 75 kg/m (151.2 lb/yd) rails also have been used on heavy-duty railroads like Baikal-Amur Mainline, but have proven themselves deficient in operation and were mainly rejected in favor of 65 kg/m (131 lb/yd) rails.[2]
North America
Weight mark on a jointed segment of 155 lb/yd (76.9 kg/m) "Pennsylvania Special" rail, the heaviest grade of rail ever mass produced
The American Society of Civil Engineers (or ASCE) specified rail profiles in 1893 for 5-pound-per-yard (2.48 kg/m) increments from 40 to 100 pounds per yard (19.8 to 49.6 kg/m). Height of rail equaled width of foot for each ASCE tee-rail weight; and the profiles specified fixed proportion of weight in head, web and foot of 42%, 21% and 37%, respectively. ASCE 90 lb/yd (44.6 kg/m) profile was adequate; but heavier weights were less satisfactory. In 1909 the American Railway Association (or ARA) specified standard profiles for 10 lb/yd (4.96 kg/m) increments from 60 to 100 lb/yd (29.8 to 49.6 kg/m). The American Railway Engineering Association (or AREA) specified standard profiles for 100 lb/yd (49.6 kg/m), 110 lb/yd (54.6 kg/m) and 120 lb/yd (59.5 kg/m) rails in 1919, for 130 lb/yd (64.5 kg/m) and 140 lb/yd (69.4 kg/m) rails in 1920, and for 150 lb/yd (74.4 kg/m) rails in 1924. The trend was to increase rail height/foot-width ratio and strengthen the web. Disadvantages of the narrower foot were overcome through use of tie-plates. AREA recommendations reduced the relative weight of rail head down to 36%, while alternative profiles reduced head weight to 33% in heavier weight rails. Attention was also focused on improved fillet radii to reduce stress concentration at the web junction with the head. AREA recommended the ARA 90 lb/yd (44.6 kg/m) profile.[3] Old ASCE rails of lighter weight remained in use, and satisfied the limited demand for light rail for a few decades. AREA merged into the American Railway Engineering and Maintenance-of-Way Association in 1997. By the mid-20th century, most rail production was medium heavy (112 to 119 lb/yd/55.6 to 59.0 kg/m) and heavy (127 to 140 lb/yd/63.0 to 69.4 kg/m) Sizes under 100 lb/yd (49.6 kg/m) rail are usually for lighter duty freight, low use trackage, or light rail. Track using (100 to 120 lb/yd (49.6 to 59.5 kg/m)) rail is for lower speed freight branch lines or rapid transit (for example, most of the New York City Subway system track is constructed with 100 lb/yd (49.6 kg/m) rail). Main line track is usually built with 130 lb/yd (64.5 kg/m) rail or heavier. Some common North American rail sizes include:[4]
 - 75 lb/yd (37.2 kg/m) (ASCE)
 - 85 lb/yd (42.2 kg/m) (ASCE)
 - 90 lb/yd (44.6 kg/m) (ARA)
 - 100 lb/yd (49.6 kg/m) (AREA)
 - 105 lb/yd (52.1 kg/m) New York Central Railroad
 - 115 lb/yd (57.0 kg/m) (AREA)
 - 119 lb/yd (59.0 kg/m) Colorado Fuel and Iron
Some common North American crane rail sizes include:
 - 12 lb/yd (5.95 kg/m)
 - 20 lb/yd (9.9 kg/m)
 - 25 lb/yd (12.4 kg/m)
 - 30 lb/yd (14.9 kg/m)
 - 40 lb/yd (19.8 kg/m)
 - 60 lb/yd (29.8 kg/m)
 - 80 lb/yd (39.7 kg/m)
 - 85 lb/yd (42.2 kg/m)
 - 104 lb/yd (51.6 kg/m)
 - 105 lb/yd (52.1 kg/m)
 - 135 lb/yd (67 kg/m)
 - 171 lb/yd (84.8 kg/m)
 - 175 lb/yd (86.8 kg/m)
Australia
Some common Australian rail sizes include:
 - 30 kg/m (60.5 lb/yd)
 - 36 kg/m (72.6 lb/yd)
 - 40 kg/m (80.6 lb/yd)
 - 47 kg/m (94.7 lb/yd)
 - 50 kg/m (100.8 lb/yd)
 - 53 kg/m (106.8 lb/yd)
 - 60 kg/m (121 lb/yd)
 - 68 kg/m (137.1 lb/yd) (no longer production)
 - 50 kg and 60 kg are the current standard, although some other sizes are still manufactured.[5]
 - Some American sizes are used on northwest Western Australian iron ore railways.
History
Fishbelly edge rails laid on stone blocks
Cross sections of early rails
Early rails were used on horse drawn wagonways, originally with wooden rails,[6] but from the 1760s using strap-iron rails, which consisted of thin strips of cast iron fixed onto wooden rails.[7] These rails were too fragile to carry heavy loads, but because the initial construction cost was less, this method was sometimes used to quickly build an inexpensive rail line. Strap rails sometimes separated from the wooden base and speared into the floor of the carriages above, creating what was referred to as a "snake head." However, the long-term expense involved in frequent maintenance outweighed any savings.[8][9]
These were superseded by cast iron rails which were flanged (i.e. 'L' shaped) with the wagon wheels being flat, an early exponent being Benjamin Outram. His partner William Jessop had pioneered the use of "edge rails" in 1789 where the wheels were flanged and, over time it was realised that these worked better.
The earliest of these in general use were the so-called cast iron fishbelly rails from their shape. Rails made from cast iron were brittle and broke easily. They could only be made in short lengths which would soon become uneven. John Birkinshaw's 1820 patent,[10] as rolling techniques improved, introduced wrought iron in longer lengths, replaced cast iron and contributed significantly to the explosive growth of railroads in the period 1825-40. The


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Pravega write latency is of the order of milliseconds. It seamlessly scales to handle high throughput reads and writes from thousands of concurrent clients, making it ideal for IoT and other time sensitive applications.
Streams are light weight, Pravega can support millions of Streams, this frees the application from worrying about static configuration of Streams and preallocating a small fixed number of Streams and limiting Stream resource.
Write operations in Pravega are low latency, under 10ms to return an acknowledgment is returned to a Writer. Furthermore, writes are optimized so that I/O throughput is limited by network bandwidth; the persistence mechanism is not the bottleneck. Pravega uses Apache BookKeeper to persist all write operations. BookKeeper persists and protects the data very efficiently. Because data is protected before the write operation is acknowledged to the Writer, data is always durable. As we discuss below, data durability is a fundamental characteristic of a storage primitive. To add further efficiency, writes to BookKeeper often involve data from multiple Stream Segments, so the cost of persisting data to disk can be amortized over several write operations.
There is no durability performance trade-off with Pravega.
A Reader can read from a Stream either at the tail of the Stream or at any part of the Stream's history. Unlike some log-based systems that use the same kind of storage for tail reads and writes as well as reads to historical data, Pravega uses two types of storage.
- The tail of the Stream is in so-called Tier 1 storage.
- The historical part of the Stream is in Tier 2 Storage.
Pravega uses efficient in-memory read ahead cache, taking advantage of the fact that Streams are usually read in large contiguous chunks and that HDFS is well suited for those sort of large, high-throughput reads. It is also worth noting that tail reads do not impact the performance of writes.
Data in Streams can be retained based on the application needs. It is constrained to the amount of data available, which is unbounded given the use of cloud storage in Tier 2. Pravega provides one convenient API to access both real-time and historical data. With Pravega, batch and real-time applications can both be handled efficiently; yet another reason why Pravega is a great storage primitive for Kappa architectures.
If there is a value to retain old data, why not keep it around? For example, in a machine learning example, you may want to periodically change the model and train the new version of the model against as much historical data as possible to enhance and yield more accurate predictive power of the model. With Pravega auto-tiering, retaining lots of historical data does not affect the performance of tail reads and writes.
Size of a stream is not limited by the storage capacity of a single server, but rather, it is limited only by the storage capacity of your storage cluster or cloud provider. As cost of storage decreases, the economic incentive to delete data goes away.
Use Pravega to build pipelines of data processing, combining batch, real-time and other applications without duplicating data for every step of the pipeline.
Consider the following data processing environment:
- Real time processing using Spark, Flink, and or Storm
- Batch processing using Hadoop
- Full text search can be performed using Lucene-based or Search mechanism like Elastic Search.
- Micro-services apps can be supported using one (or several) NoSQL databases.
Using traditional approaches, one set of source data, for example, sensor data from an IoT app, would be ingested and replicated separately by each system. You would end up with three replicas of the data protected in the pub/sub system, three copies in HDFS, three copies in Lucene and three copies in the NoSQL database. When we consider the source data is measured in TB, the cost of data replication separated by middleware category becomes prohibitively expensive.
Consider the same pipeline using Pravega and middleware adapted to use Pravega for its storage:
With Pravega, the data is ingested and protected in one place; Pravega provides the single source of truth for the entire pipeline. Furthermore, with the bulk of the data being stored in Tier 2 enabled with erasure coding to efficiently protect the data, the storage cost of the data is substantially reduced.
With Pravega, you don't face a compromise between performance, durability and consistency. Pravega provides durable storage of streaming data with strong consistency, ordering guarantees and great performance.
Durability is a fundamental storage primitive requirement. Storage that could lose data is not reliable storage. Systems based on such storage are not production quality.
Once a write operation is acknowledged, the data will never be lost, even when failures occur. This is because Pravega always saves data in protected, persistent storage before the write operation returns to the Writer.
With Pravega, data in the Stream is protected. A Stream can be treated as a system of record, just as you would treat data stored in databases or files.
A developer uses a Pravega Transaction to ensure that a set of events are written to a Stream atomically.
A Pravega Transaction is part of Pravega's Writer API. Data can be written to a Stream directly through the API, or an application can write data through a Transaction. With Transactions, a Writer can persist data now, and later decide whether the data should be appended to a Stream or abandoned.
Using a Transaction, data is written to the Stream only when the Transaction is committed. When the Transaction is committed, all data written to the Transaction is atomically appended to the Stream. Because Transactions are implemented in the same way as Stream Segments, data written to a Transaction is just as durable as data written directly to a Stream. If a Transaction is abandoned (e.g. if the Writer crashes) the Transaction is aborted and all data is discarded. Of course, an application can choose to abort the Transaction through the API if a condition occurs that suggests the Writer should discard the data.
Transactions are key to chaining Flink jobs together. When a Flink job uses Pravega as a sink, it can begin a Transaction, and if it successfully finishes processing, commit the Transaction, writing the data into its Pravega based sink. If the job fails for some reason, the Transaction times out and data is not written. When the job is restarted, there is no "partial result" in the sink that would need to be managed or cleaned up.
Combining Transactions and other key features of Pravega, it is possible to chain Flink jobs together, having one job's Pravega based sink be the source for a downstream Flink job. This provides the ability for an entire pipeline of Flink jobs to have end-to-end exactly once, guaranteed ordering of data processing.
Of course, it is possible for Transactions across multiple Streams be coordinated with Transactions, so that a Flink job can use two or more Pravega based sinks to provide source input to downstream Flink jobs. In addition, it is possible for application logic to coordinate Pravega Transactions with external databases such as Flink's checkpoint store. For more information, see Transaction section.


text:
Title and statement of responsibility area
Bon Accord Board of Trade fonds
General material designation
- Textual record
Other title information
Title statements of responsibility
Level of description
Edition statement of responsibility
Class of material specific details area
Statement of scale (cartographic)
Statement of projection (cartographic)
Statement of coordinates (cartographic)
Statement of scale (architectural)
Issuing jurisdiction and denomination (philatelic)
Dates of creation area
- Bon Accord Board of Trade
Physical description area
0.10 m of textual records.
Publisher's series area
Title proper of publisher's series
Parallel titles of publisher's series
Other title information of publisher's series
Statement of responsibility relating to publisher's series
Numbering within publisher's series
Note on publisher's series
Archival description area
Name of creator
The Bon Accord Board of Trade was founded in the town of Bon Accord, Alberta in 1914. The board was founded to better living and working conditions in the town by improving water supply, railway schedules, postal service, sidewalks, electric power service, and others.
The records were maintained by the Board of Trade and donated by former board member William Deedman in 1970.
Scope and content
The fonds consists of minutes, financial statements, correspondence, and working records of the Bon Accord Board of Trade.
Immediate source of acquisition
William Deedman donated the records in 1970.
Language of material
Script of material
Location of originals
Availability of other formats
Restrictions on access
Terms governing use, reproduction, and publication
File list is available.
Further accruals are not expected.


text:
tendency - meaning in Telugu
Pronunciation of tendencyటేన్డన్సీ
Meanings of tendency in Telugu[Show Transliteration]
Inflected formstendencies (noun plural)
Definitions and Meaning of tendency in Englishtendency - noun
- an attitude of mind especially one that favors one alternative over others
- a tendency to be too strict
- an inclination to do something
- a characteristic likelihood of or natural disposition toward a certain condition or character or effect
- fabric with a tendency to shrink
- a general direction in which something tends to move
- the trend of the stock market
Information provided on tendency
Meaning and definitions of tendency, translation in Telugu language for tendency with similar and opposite words. Also find spoken pronunciation of tendency in Telugu and in English language.
Tags for the entry "tendency"
Hindi meaning of tendency, tendency meaning in Telugu, tendency definition, examples and pronunciation of tendency in Telugu language.
Also see: tendency in Hindi


text:
Changes in store for fishing, hunting codes
By BRUCE A. SCRUTON
The New Jersey Fish and Game Council has adopted changes to the 2011-2012 Game Code, which takes effect this year, but there is still time to comment on the proposed changes to the 2012-2013 Fish Code.
A public hearing on the code changes will be held at 7 p.m. Sept. 13 at the Central Regional Office in the Assunpink Wildlife Management Area in Robbinsville.
Written comments on the code changes will be accepted until Sept. 30.
The fish code governs when, by what means, at which locations, in what numbers and at what sizes, fish may be pursued, caught, killed or possessed in New Jersey.
Perhaps the biggest change will be the imposition of a daily creel and possession limit of 25 in total for any species of freshwater fish that do not have a specific daily creel or possession limit. Currently there is a 25 fish total limit on species of warmwater fish, which do not have a specific creel or possession limit.
In general, all fish that live in lakes, ponds, streams and rivers are "fresh" water fish. However some species, such as trout, require cold, running water to survive while other species, such as bass, perch, pike and catfish can live in water with much warmer water temperatures.
According to the document that outlines the changes, the code is seeking to "proactively protect these and other non-typical game species in New Jersey as future trends in the targeting of fish species is unknown."
The extension of creel limits will not apply to the Delaware River and Greenwood Lake since those bodies of water fall under jurisdiction of New Jersey and another state.
A proposed inclusion of yellow perch and white perch as fish that cannot be snagged would effectively make snagging illegal across the state. The code changes the term "foul hooking" to "snagging."
The code will also seek to list 61 native species of fish in the fresh waters of New Jersey as "indigenous" fish. This will bring the code into agreement with other laws that regulate the release of indigenous, exotic and potentially dangerous fish.
Among the amendments are limits on what species of fish can be taken with a bow and arrow.
Currently, a dozen species of fish including most trout, salmon, bass, pike, walleye and muskellunge are prohibited to be taken since catch and release is impractical and there are size limits on those species.
The code now realizes there are other species of fish, most of which are not targeted by bow anglers anyway, which should be listed as prohibited species.
As a result, the code proposes to identify the species that may be taken by bow anglers such as carp, eels, flathead catfish, shad, snakeheads and suckers.
In inland waters, channel catfish will remain on the prohibited list for archers, however, will be a legal target fish, in the Delaware River. The code notes that channel catfish do not reproduce in inland waters, but do reproduce in the Delaware.
The code also clarifies that recurve and compound bows and longbows are permitted. Crossbows are prohibited for bow fishing.
And, to bring consistency between New Jersey and Pennsylvania codes, there is a change to allow a three-rod limit for both shoreline and boat anglers in the Delaware River.
Pennsylvania is making a similar change to three rods effective Jan. 1.
Many other changes are proposed to boundaries for various trout waters across the state and to establish the first day of trout season for the 2013 to 2016 seasons.
The full document outlining all the changes is available at: _URL_
Written comments should be submitted by Sept. 30 to Gary J. Brower, Esq.; Attn: Docket 10-11-06; Office of Legal Affairs; Department of Environmental Protection; Mail Code 401-04L; 401 East State St. 4th Floor, P.O. Box 402; Trenton, N.J. 08625.
Among the changes to the game code are the addition of five days to the rabbit and hare hunting season; statewide closure of the bobwhite quail season with the exception of the Greenwood and Peaslee Wildlife Management Areas; creation of special black bear farm permits; addition of a second Saturday for the fall turkey hunting season; expansion of the early bow and arrow-only coyote and fox season and regular coyote and fox season dates.
The code also eliminates the separate black bear hunting seminar since that material will become part of the regular hunter eduction
The game code also removes the requirement for youth hunters to take an antlerless deer before an antlered deer during the early fall bow deer season.
The new game code will be published online later this month and available in booklet form through license agents the first week of September.


__Virtual Machines__ * Underlying architecture has to cause a trap before it does anything that would interfere with the virtual machine - x86 architecture is not properly virtualizable * An x86 process can tell whether it is running under supervisor or user state. - If running an OS on the VM, the OS can read the state in a register. It expects supervisor, but since it is running virtualized, it will read user. * There are supervisor state instructions that you can execute in user mode without trapping and produce incorrect results - example: popf changes different flags in user state and supervisor state. Traps in neither case. * But people still build virtual machines on x86. How? - VMware uses "runtime binary translation": * Go through code, identify instructions that are not properly virtualized, and rewrite the code to fix the problem. * This is done as the code is encountered at runtime, but only once for each segment of code. * Question: Why not interpret all of the instructions? - Performance issuethis would run around 100x slower. - We want to run as much natively as we can, and trap on anything that would interfere with the VM. __Performance Evaluation__ * A little less concerned with performance these days because faster computing is cheaper than it used to be. * Techniques: - Analytic modeling - Simulation modeling (hw1) - System tuning - Design improvement * To improve performance, you need to know what the current performance is. * One of the most difficult issues is measurement. - Collecting the data is usually the most time-consuming part. * Measurement - Hardware monitoring * Connect probes to parts of the system - But if you can't get to a part of the chip, then you can't monitor it - Need the hardware manufacturer to bring the symbols to the periphery of the chip or to registers - Unfortunately, performance connections are usually the first part of a design to be tossed out due to deadlines. * Hardware monitors usually have some logic built in for data reduction. * Sampling randomly is important. - Software monitoring * Can sample on interrupts - The drawback is that you can never sample in the middle of non-interruptible code. * Compiler can build in profiling instructions to compiled code. * Microcoded machine - could instrument microcode if the computer allows it. * Overhead is an issue - need to make sure the monitoring doesn't dominate - this will mess up the performance analysis * Examples: IBM's GTF, invoked on traps and interrupts to dump data to a file or tape. Designed for debugging. - Hardware counters * Built-in counters than can be used to count certain values, and can be read at different intervals - Can count, for example: cache misses, main memory accesses, types of instructions, numbers of branches * Workload Characterization - Need to know what sort of workload will be run on a system to measure performance. - Executable workloads: Collect a sample of actual workloads to test with. Must assume that its representative. - Synthetic executable workload: Make a reasonable guess about what would be a representative workload. - Synthetic is required if a new system is being tested for which no real workloads yet exist. - How to characterize a workload: * Know your parameters. * Statistical methods - Not necessarily as important as understanding how the system works. - Can usually get by with some simple statistical tools: means, variances, distributions, factor analysis, some modeling. * Analytic Models - Markov chains - Other stochastic processes - Queueing theory models * Queueing theory goes back ~100 years. Was driven by telecommunications. * Problems in queing theory (as in many other fields) fit a "hockey stick curve" with problem difficulty vs. difficulty to solve. - easy to intermediate problems solvable without much work. - as soon as the problems get somewhat difficult, the difficulty to solve goes up pretty quickly. * Queueing networks - HW1 was a very simple queing network with one server, one queue. - BCMP type queueing networks can be solved with some boilerplate (but exponential in the number of states): * Different customer types * Transition probabilities between servers and types * Different server types allowed: - FCFS exponential (runtime of serve is exponential); models I/O - Processor sharing (each of N servers gets 1/N of processing power); models CPU - Infinite server (each customer gets the full rate of the server); models customer thinking * Discrete Event Simulation - Events can come from a trace of a real system, with time and type information. - Or, generate events with a random number generator as in HW1 * Continuous Simulation - Not usually used for computer system modeling - Example: Find the area of some amoeba-looking curve-bounded region using a stochastic method * Bound it with a box with known aread, sample random points in the box. The proportion of points that fall in the boundary of the curve multiplied by the box's area is the region's area. * This is a Monte Carlo sampling method. - Continuous simulation used to solve non-CS problems (ex. aerodynamics problems). * Can solve differential equations numerically rather than symbolically. * Regenerative Simulation - Find a regeneration point in the model. - We can restart the simulation from this point with different events from this point - IID (independent, identically distributed) events * Back of the Envelope Calculations - Sufficient in many cases. Use common-sense information to approximate the answer to some question. - Ex: How much water flows down the Mississippi every day?


text:
Connect the input pins to the sensing resistor using a Kelvin or 4-wire connection. This connection technique makes sure that only the current-sensing resistor impedance is detected between the input pins. Poor routing of the current-sensing resistor commonly results in additional resistance present between the input pins. Given the very low ohmic value of the current resistor, any additional high-current carrying impedance can cause significant measurement errors.
Place the power-supply bypass capacitor as close as possible to the device power supply and ground pins. The recommended value of this bypass capacitor is 0.1 µF. Additional decoupling capacitance can be added to compensate for noisy or high-impedance power supplies.
When routing the connections from the current sense resistor to the device, keep the trace lengths as close as possible in order to minimize any impedance mismatch..


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Does Alexandria Plan Require Me to Adopt a Particular Method of Instruction?
No. The way a teacher chooses to prepare students to approach the study of a text depends on their teaching style and the needs of their students. The teacher may choose to have students read short sections of text with a few assigned questions, preparing students to participate fully in discussion. The teacher may also choose to have students work in pairs or small groups to read and to discuss questions orally--preparing to pull their ideas together for a rich whole class seminar or discussion. Another teacher may want to allow students to first grapple with the text independently. During their first read, students might circle passages where they are confused and/or underline points that they thought were important. Students might annotate the passage with questions and notes. As the teacher circulates during independent reading block, he or she could note how the students' questions gather throughout the passage. The teacher could then use the TDQs to clarify misunderstandings as needed and to dive deeper into the text than students were able to independently. We offer these questions for teachers to use as they see fit.


Jacksonian seizure definition - Medical Dictionary: Definitions of Popular Terms Defined on MedTerms
Definition of Jacksonian seizure
Jacksonian seizure: A form of epilepsy involving brief alteration in movement, sensation or nerve function caused by abnormal electrical activity in a localized area of the brain. Jacksonian seizures is a form of simple complex seizures in which the abnormal electrical activity is localized to one region in the brain. Seizures of this type typically cause no change in awareness or alertness. They are transient, fleeting, and ephemeral.
Jacksonian seizures are extremely varied and may involve, for example, apparently purposeful movements such as turning the head, eye movements, smacking the lips, mouth movements, drooling, rhythmic muscle contractions in a part of the body, abnormal numbness, tingling, and a crawling sensation over the skin.
These seizures are named for the English neurologist, John Hughlings Jackson, who studied speech defects in brain disorders and confirmed the location in the brain of the speech center ("Broca's center"). He described what are today called Jacksonian seizures in 1863 and in 1875 found the areas in the brain that caused them. Jackson was among the towering figures of 19th-century medicine, one of "the great men of medicine." (There were few, if any, women in medicine in the 19th century.)
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text:
1. Sobhana. An ārāma, given by Upāli in a previous birth as Sumana, for the use of Padumuttara Buddha. ThagA.i.362.
2. Sobhana. A householder (kutumbika). Ananda, born as Sumana, bought his park (also called Sobhana) for one sum of one hundred thousand and built in it a vihāra for Padumuttara Buddha. ThagA.ii.123; DA.ii.490; SA.ii.69f.; AA.i.162, etc.
3. Sobhana. The city of birth of Atthadassī Buddha, where he later preached to his relations. Bu.xv.5, 14; BuA.179; but J.i.39 calls it Sobhita.
4. Sobhana. A city, built by Vessakamma for the use of Ukkāsatika, in his birth as a Cakkavatti, fifty five kappas ago. Ap.ii.414.
5. Sobhana. v.l. for Sobha.


Diplôme Supérieur d'Arts Appliqués Lyon
École Supérieure d'Arts Appliqués La Martinière Diderot
Snowboard and protection
Antoine BONTE. Diploma project. DSAAD Product design. 2020
Sliding sports are not easy to access. We need to be fully equipped which is expensive and cumbersome. Moreover, learning to practice them is a hard task. This is why, as a designer, I aim to make them accessible. It should not distort the environment : it is the soul of those sports.
When sliders are practising, it increases the potential energy in their body. That is why they are exposed to personal injuries or even death if they do not control it. However, if we want to improve our skills, we need to practise. In that kind of sports, we learn from our mistakes.
This learning method scares a lot of people. That is why I will suggest reducing personal injuries via a new kind of accessible protections that do not hinder movement.


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Compartment Pressure Test
Chronic Exertional Compartment Syndrome (CECS) is a condition where exercise induces high pressure within a closed space, which results in decrease tissue perfusion causing symptoms such as pain, cramping, burning, tightness and weakness of the effected lower limb. The reason why this occurs is not known, however four factors are believed to contribute to an increase in compartment pressure.
- Inelasticity of the fascial sheath
- Increase in volume of skeletal muscle secondary to blood volume and edema
- Muscle hypertrophy in response to exercise
- Dynamic contraction factors due to demands in the gait cycle.
Note: Recently the supplement creatine has been implemented as a cause of CECS in athletes due to its effect on fluid retention and increase in muscle size.
Anyone can develop CECS, but it is more common in athletes who participate in sports that involve repetitive movements such as running.
Compartment Pressure Testing is the "Gold Standard" for diagnosis CECS. The test involves inserting a small catheter under local anaesthetic into one of the four well recognized Compartments (Anterior, Lateral, Deep Posterior and Superficial Posterior) of the lower leg.
Along with the history, compartment pressure testing is an extremely useful diagnostic tool to exclude other causes of exercise induced leg pain such as stress fractures, periostitis, Medial Tibial Stress Syndrome various tendinopathies, neurological compression syndromes and infection.


text:
The mobile edge computing (MEC) paradigm changes the role of edge devices from data producers and requesters to data consumers and processors. MEC mitigates the bandwidth limitation between the edge server and the remote cloud by directly processing the large amount of data locally generated by the network of the internet of things (IoT) at the edge. An efficient data-gathering scheme is crucial for providing quality of service (QoS) within MEC. To reduce redundant data transmission, this paper proposes a data collection scheme that only gathers the necessary data from IoT devices (like wireless sensors) along a trajectory. Instead of using and transmitting location information (which may leak the location anonymity), a virtual coordinate system called 'distance vector of hops to anchors' (DV-Hop) is used. The proposed trajectory encoding algorithm uses ellipse and hyperbola constraints to encode the position of interest (POI) and the trajectory route to the POI. Sensors make routing decisions only based on the geometric constraints and the DV-Hop information, both of which are stored in their memory. Also, the proposed scheme can work in heterogeneous networks (with different radio ranges) where each sensor can calculate the average one-hop distance within the POI dynamically. The proposed DV-Hop updating algorithm enables the users to collect data in an IoT network with mobile nodes. The experiments show that in heterogeneous IoT networks, the proposed data collection scheme outperforms two other state-of-the-art topology-based routing protocols, called ring routing, and nested ring. The results also show that the proposed scheme has better latency, reliability, coverage, energy usage, and provide location privacy compared to state-of-the-art schemes.
X. Cao and S. K. Madria, "Efficient Data Collection in IoT Networks using Trajectory Encoded with Geometric Shapes," IEEE Transactions on Sustainable Computing, vol. 7, no. 4, pp. 799 - 813, Institute of Electrical and Electronics Engineers, Oct 2022.
The definitive version is available at _URL_
Keywords and Phrases
DV-Hop; edge computing; ellipse; encoding; GPS-free; hyperbola; IoT; routing; sensor; Trajectory
International Standard Serial Number (ISSN)
Article - Journal
© 2023 Institute of Electrical and Electronics Engineers, All rights reserved.
01 Oct 2022
National Science Foundation, Grant CNS _PHONE_


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–Builders Need to Inspect and Maintain Storm Drain "Socks"
With onset of the rainy season, Seattle DCI is reminding builders working in Seattle to inspect and maintain any temporary storm drain inserts they have installed as part of construction projects.
The inserts, also known as storm drain socks, are used on many construction projects to catch sediment not captured upstream by other construction-related erosion control devices.
Regulations for the use of the socks include the following:
- Inspections should be made on a regular basis, especially after large storm events. Inlet protection devices shall be cleaned or removed and replaced when sediment has filled one-third of the available storage (unless a different standard is specified by the product manufacturer).
- Do not wash sediment into storm drains while cleaning. Spread all excavated material evenly over the surrounding land area or stockpile and stabilize as appropriate.
- Remove the inserts within 5 business days after the final site stabilization is achieved, or after it is no longer needed, whichever is longer (BMP E3.25*). If inserts are removed during times of flooding, the builder is responsible for re-installing them per regulations.
To prevent flooding, the public is urged to clear clogged drains where it is safe and practical to do so. Flooding should be reported to Seattle Public Utilities at _PHONE_.
You can find the rules for the use of the socks in our Construction Stormwater Control and Soil Amendment Standard Plan on our forms web page.
* See Director's Rule Seattle DCI 21-2015, SPU DWW-200: Stormwater Manual.


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One Stop Shop (OSS) for e-commerce in the European Union
From last Thursday, July the 1srt, and after delaying its entry into force due to the health crisis of the COVID-19, the One Stop Shop (OSS) System applicable to e-commerce enters into force in the Member States of the European Union. To date, this system has only been applied to Electronically Supplied Services (ESS) through the MOSS system.
First of all, it should be highlighted that this new system simplifies the tax regime of online sales: the supplier that materializes online sales charges VAT to the country of destination (when the sales exceed 10.000.-€ annual turnover in the EU, being the unified criterion) without taking into account the previous requirements of tax representation in each Member State or of the different economic scales of each jurisdiction.
In this sense, VAT records are simplified through the One Stop Shop procedure: e-commerce companies will only have to make one registration for their "Identification Status". Consequently, for employers with a registered office in one of the Member States of the European Union, the State of identification will be the same State as the State where the registered office is located. However, for companies established outside the European Union, their State of identification will be the State from which they make intracommunity deliveries.
In other words, the foreseeable consequences of this new system for employers are: first, a great simplification of the procedures and formalities (and consequently, of the costs associated to the identification and to the tax representation) previously required by VAT registration, since the employer can be registered in a single Member State for all the intracommunity deliveries. Second, as this registration is carried out in a single Member State, the VAT return is also unique: it will only be necessary to submit it to the State of identification of the employer for all the deliveries made within the European Union. Similarly, the accrued VAT will be settled through a single payment determined by this single declaration.
Therefore, Andorran entrepreneurs engaged in e-commerce who make deliveries to any State of the European Union will only have to register in one Member State of the Union and pay the VAT accrued in that same State.
This is undoubtedly an evolution of great relevance to simplify the procedures for intracommunity operators (regardless of whether they are located outside the Union) which, in turn, makes it possible for those parties to comply with their formal obligations, especially for these entities that, with the previous system, could have found a real barrier to the entry of the market because of its high cost.


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10.2 Geostrophic Equations
The geostrophic balance requires that the Coriolis force balance the horizontal pressure gradient. The equations for geostrophic balance are derived from the equations of motion assuming the flow has no acceleration, du/dt = dv/dt = dw/dt = 0; that horizontal velocities are much larger than vertical, w << u, v; that the only external force is gravity; and that friction is small. With these assumptions (7.12) become
where f = 2 Ω sin φ is the Coriolis parameter. These are the geostrophic equations.
The equations can be written:
where p0 is atmospheric pressure at z = 0, and ζ is the height of the sea surface. Note that we have allowed for the sea surface to be above or below the surface z = 0; and the pressure gradient at the sea surface is balanced by a surface current us.
Substituting (10.7b) into (10.7a) gives:
where we have used the Boussinesq approximation, retaining full accuracy for ρ only when calculating pressure.
In a similar way, we can derive the equation for v.
If the ocean is homogeneous and density and gravity are constant, the first term on the right-hand side of (10.8) is equal to zero; and the horizontal pressure gradients within the ocean are the same as the gradient at z = 0. This is barotropic flow described in §10.4.
If the ocean is stratified, the horizontal pressure gradient has two terms, one due to the slope at the sea surface, and an additional term due to horizontal density differences. These equations include baroclinic flow also discussed in §10.4. The first term on the right-hand side of (10.8) is due to variations in density ρ(z), and it is called the relative velocity. Thus calculation of geostrophic currents from the density distribution requires the velocity (u0, v0) at the sea surface or at some other depth.
|Department of Oceanography, Texas A&M University
Robert H. Stewart, _EMAIL_
All contents copyright © 2005 Robert H. Stewart,
All rights reserved
Updated on October 17, 2005


ック
Anywhere you'd put an identifier (or chain of identifiers) as part of a variable or subroutine name, you can replace the identifier with a BLOCK returning a reference of the correct type. In other words, the previous examples could be written like this:
変数名やサブルーチン名の一部として識別子を置くところでは、適切な型の リファレンスを返す BLOCK を伴う識別子で置き換えることができます。 言い換えると、先の例は以下のように書くことができます:
 $bar = ${$scalarref};
 push(@{$arrayref}, $filename);
 ${$arrayref}[0] = "January";
 ${$hashref}{"KEY"} = "VALUE";
 &{$coderef}(1,2,3);
 $globref->print("output\n"); # iff IO::Handle is loaded
Admittedly, it's a little silly to use the curlies in this case, but the BLOCK can contain any arbitrary expression, in particular, subscripted expressions:
確かにこの場合には中かっこを付けるのはばかげたことかもしれませんが、 BLOCK には任意の式、特に添字を付けた式を入れることができます:
 &{ $dispatch{$index} }(1,2,3); # call correct routine
Because of being able to omit the curlies for the simple case of $$x, people often make the mistake of viewing the dereferencing symbols as proper operators, and wonder about their precedence. If they were, though, you could use parentheses instead of braces. That's not the case. Consider the difference below; case 0 is a short-hand version of case 1, not case 2:
単純な <$$x> の場合には中かっこが省略できるので、シンボルの デリファレンスを適当な演算子のように受け取って、その優先順位はどのくらいかと 悩む人があります。 しかし、もし演算子であれば、中かっこの代わりに、普通の括弧が 使えることでしょう。 そうではありません。 以下の違いを考えてみてください; CASE 0 は、CASE 1 を短くしたものであり、 CASE 2 を短くしたものでは ありません:
 $$hashref{"KEY"} = "VALUE"; # CASE 0
 ${$hashref}{"KEY"} = "VALUE"; # CASE 1
 ${$hashref{"KEY"}} = "VALUE"; # CASE 2
 ${$hashref->{"KEY"}} = "VALUE"; # CASE 3
Case 2 is also deceptive in that you're accessing a variable called %hashref, not dereferencing through $hashref to the hash it's presumably referencing. That would be case 3.
CASE 2 もまた間違えやすいもので、%hashref という変数を アクセスするものです; $hashref を仲介して、それが指すことになっている ハッシュをデリファレンスしているものではありません。 それは、CASE 3 です。
矢印記法
Subroutine calls and lookups of individual array elements arise often enough that it gets cumbersome to use method 2. As a form of syntactic sugar, the examples for method 2 may be written:
配列の個々の要素を使う場合が増えると、2 番の方法を使うのが 煩わしくなってきます。 構文上の打開策として上記の 2 行は、以下のように書けます:
 $arrayref->[0] = "January"; # Array element
 $hashref->{"KEY"} = "VALUE"; # Hash element
 $coderef->(1,2,3); # Subroutine call
The left side of the arrow can be any expression returning a reference, including a previous dereference. Note that $array[$x] is not the same thing as $array->[$x] here:
矢印の左側には先行するデリファレンスを含めて、リファレンスを返す任意の式が 書けます。 $array[$x] は、$array->[$x]同じではない ことに 注意してください:
 $array[$x]->{"foo"}->[0] = "January";
This is one of the cases we mentioned earlier in which references could spring into existence when in an lvalue context. Before this statement, $array[$x] may have been undefined. If so, it's automatically defined with a hash reference so that we can look up {"foo"} in it. Likewise $array[$x]->{"foo"} will automatically get defined with an array reference so that we can look up [0] in it. This process is called autovivification.
これが、先の左辺値コンテキストで用いるとリファレンスが 存在するようになるというケースの一つです。 この文以前には、$array[$x] は未定義かもしれません。 その場合自動的にハッシュリファレンスと定義されて、{"foo"} が 検索できるようになります。 同じように $array[$x]->{"foo"} が配列リファレンスで定義されるので、 [0] をそこで探すことができます。 このプロセスは 自動有効化 (autovivification) と呼ばれます。
One more thing here. The arrow is optional between brackets subscripts, so you can shrink the above down to
もう一つ。 矢印は、括弧付きの添字の では、省略することができるので、 上の例は、以下のように書けます:
 $array[$x]{"foo"}[0] = "January";
Which, in the degenerate case of using only ordinary arrays, gives you multidimensional arrays just like C's:
通常の配列だけを使うように限定すれば、ちょうど C の多次元配列のように 使うことができます:
 $score[$x][$y][$z] += 42;
Well, okay, not entirely like C's arrays, actually. C doesn't know how to grow its arrays on demand. Perl does.
ああ、そうだ、実際には全く C の配列と同じという訳ではありません。 C では、必要に応じて配列を大きくするなどということはできません。 Perl では、それができます。
オブジェクト
If a reference happens to be a reference to an object, then there are probably methods to access the things referred to, and you should probably stick to those methods unless you're in the class package that defines the object's methods. In other words, be nice, and don't violate the object's encapsulation without a very good reason. Perl does not enforce encapsulation. We are not totalitarians here. We do expect some basic civility though.
リファレンスが、オブジェクトに対するものである場合には、参照されるものを アクセスするためのメソッドがあるはずで、オブジェクトのメソッドを定義する クラスパッケージ内でなければ、そのメソッドを使うようにした方が良いでしょう。 言い換えると、良識をもって、特別正当な理由がない限り、 オブジェクトのカプセル化を反古にしてはいけないということです。 Perl は、カプセル化を強要したりはしません。 私達は、全