Is there a physiological difference between love and infatuation?

Question: I find that people generally distinguish between love and infatuation. Is there a physiological difference between the two? Or are they biologically identical, and the difference is circumstantial?
Comment: My point was simply that the interpretation of the words is quite subjective, unless you define them in the question. E.g. dictionary.com definition #1 for infatuation is [to inspire or possess with a foolish or unreasoning passion, as of love], and love as [a profoundly tender, passionate affection for another person]. Is this how you interpret them? Or would you say they feelings are more divergent? In my opinion you could probably use either definition for each word, depending on the context.
Comment: Could you elaborate on what you feel the distinction between the 2 is? Infatuation could just mean obsession, whereas love could imply a more physical attraction?
Comment: I don't really know the difference. It's kind of what I'm asking.
Comment: I'm sure I don't know. I'm essentially asking about the biological definitions of those words, if there are any.
Comment: The distinction (if there even is one) is likely to be at the psychological level, rather than biological... but that's just my gut feeling - I've not read that anywhere!
Answer: Assuming that our emotions are the psychological manifestations of chemical changes in our bodies (an assumption I have no trouble with but one that others may take umbrage at), any emotion will be different.
If your brain can distinguish between two emotions, then the underlying chemistry through which these emotions are expressed will be different.
This is not to say that we, as scientists, can quantify this. Definitely not today at any rate. Simply that there will almost certainly be a physiological difference between any emotional state that can be differentiated by your brain. Otherwise the brain would not register different emotions.

UPDATE:
Human language has different words for different feelings. There is often a type of feeling "continuum" with different words representing different ranges on this scale. For example:
Adoration--->Love-->Infatuation-->Affection-->Indifference-->Dislike-->Hate
How you decide to qualify an emotion you are feeling is more a question of semantics than biology. The point I am making here is that each point on that scale (and every point in between that we haven't explicitly assigned a word to) will represent a slightly different mix of various chemical signals in your body.
If your question is more about the English language words love and infatuation, their definition and distinguishing between them, try posting on English.SE.
Comment: Okay, but I don't even know if the brain can differentiate between infatuation and love.
Comment: If  _you_ can differentiate, your brain can.
Comment: I don't know that I can differentiate between the two.
Comment: @Avi, see my updated answer.
Comment: That answers my question (that answer being "no").
Answer: Using the Triarchic Theory of Love proposed by Robert Sternberg, love is divided into three components:

Intimacy
Passion
Commitment

Using the theory's particular Infatuation is just the passion portion of love which is lacking in intimacy and commitment required for Consummate Love or True Love.
Physiologically speaking, this is when a certain sense of dependency comes in and as we know from years of addiction research, there is a physiological difference between liking sex physically and liking sex with a particular person for non-physical reasons.
Answer: Psychologically infatuation is associated with a projection - attributing to a person the qualities of an idealized person. This is not the only example of projection - similar explanation is given to irrational hate or immediate dislike, which are usually based on projecting a certain stereotype, attributed to a person due to their physical characteristics, superficial elements of their behavior, social status, etc. This is how people come to immediately think of a black person as a criminal, beautiful woman as promiscuous, a bearded guy as a terrorist, rich as callous, poor as lazy, etc.
Being based on superficial characteristics, such projections disappear when we get to know the person better, which is why infatuation passes after a few weeks or months - one learns that the object of one's infatuation differs from the idealized image. Then love, as opposed to infatuation, is a lasting feeling of the attachment to a person, when one is no more ignorant of their faults.


Leaving a job with a long notice period

Question: I currently work in France where the law states that a 3 month notice must be given to the employer when leaving a position. I am currently trying to move to the USA, where employers are not very sympathetic with my situation, and I have an offer for a job starting in 6 to 8 weeks, ie before the end of my notice period. Does anybody have any advice about how to talk my current employer into letting me leave early?
Comment: Can you get fired ? What constitutes "gross moral turpitude" in France?
Comment: Yes you can negotiate it down. In the worst case you are taken to court and pay a fine.
Comment: Are you considered a "cadre" or a normal employee  here.

And could you not use your Annual leave to effectively reduce your notice period.
Answer: This kind of problem should be the subject of polite and constructive negotiation.
Presumably your new US-based employer knows you are relocating from France, and presumably they offered you a job in the hopes that you will be with them for several years. The subject of the negotiation is a change of your start date at the new job of between four and six weeks. That is, objectively, not much time. So please don't exaggerate the importance of this. And please keep in mind that many companies do business around the world and are used to different employment laws in different countries.
I suggest you write to your new manager saying something like, "I need your help with something. Because of French employment law, my commitment to my present employer concludes three months after I give notice. If I am to meet my commitment, I need to start working for you on (whatever date). Is that possible? If not, what start date is possible?  I personally place a high value on meeting my commitments, and I am grateful for any help you can offer me solving this problem."
Most employers like to work with people who try to meet their commitments. This sort of approach is likely to work. The manager will probably say "ok." If the manager comes back with a shorter time, he may have a good reason for it.
At any rate, then you can go to your present employer and respectfully say "what would it take for you to release me from my commitment on (date) before the three months have expired? Here is the reason for my request."  They may say, "that will cost you 5000 euros." But they probably will say "finish certain work, and we will release you." They already know you're leaving.
Once you have had these conversations, you will understand your situation better.
Comment: Thanks Ollie for your answer. This is very useful. I would have responded to this in the comment section, but I don't have the privileges. My only issue is that I haven't put in my notice yet, so my current employer does not know that I am leaving. I am not sure that they will be willing to negotiate once I let them know. Perhaps I should have informed them months ago that I was looking to move to the US? Moreover, if they refuse to budge, I would probably have to turn down the offer as I would not be able to start at the date specified on the offer letter. Wouldn't this put me in a difficult

Leaving a job with a long notice period


How do I get all my files and lists backed up so they will open on a non-Sharepoint server?

Question: We need to move our site off Sharepoint as it is not one of the supported products(supported by my co., that is) in a security feature we must implement.
If I was moving to another sharepoint server, I know I could back up the files/lists/dbs on the current server - then restore them on the new server.
However, I'm not sure how to get a backup (create a copy) of all things on this Sharepoint server - so I can open it on another server (I only know the new server will be Windows based)?
Answer: You can use PowerShell to download all files into a Local Folder. You can export List data into an Excel File.
And use API available as part of the new server to upload it back.
<code>$web = Get-SPWeb http://siteurl
$list = $web.Lists["ListName"]
$localfolder = "C:\Backup"

RecurseFolder($list.RootFolder.Url)
foreach ($f in $list.Folders) {
    ProcessFolder($f.Url)
}

function RecurseFolder {
    param($fUrl)
    $f = $web.GetFolder($fUrl)
    foreach ($file in $f.Files) {
        $localfolder = $localfolder + "/" + $folder.Url
        if (!(Test-Path -path $localfolder))
        {
            New-Item $localfolder -type directory
        }
        $binary = $file.OpenBinary()
        $stream = New-Object System.IO.FileStream($localfolder + "/" + $file.Name), Create
        $writer = New-Object System.IO.BinaryWriter($stream)
        $writer.write($binary)
        $writer.Close()
    }
}
</code>
Comment: Thank you.  It sounds like it would definetly work (unfortunately I don't have & cannot load the sharepoint cmdlets into Powershell - and am not allowed to run shell scripts).  I long for my UNIX days :-)
Comment: You should try using SharePoint Management Shell.


default value of a variable at the time of declaration in C# and VB?

Question: Can anybody tell me what is the default value of a variable at the time of declaration in C# and vb??
Answer: In c# you can use the default keyword to determine default values.
For example:

default(bool)
default(int)
default(int?)
Comment: Nice "generic" way to get the information. Should be accepted as answer !
Comment: in 2019, default is enough.
Answer: Do you mean a (method) variable? or a field (on an instance or type)?
For a method-level variable (in C# at least) it is irrelevant, since "definite assignment" means that you must give it a value before you can read it.
Fields default to the bitwise zero state:

for reference types (including string) that means null
for Nullable<T> (int? etc) that means null
for numerics that means 0
for enums that means 0 even if there is no 0-valued enum defined
for bools that means false
for DateTime, that means the same as MinValue
for other structs, you'll have to check their documentation, but it will be a (hopefully sensible) "zero/empty" value
Answer: This can be found in MSDN:
Visual Basic .NET defines the following primitive types:
The integral value types Byte (1-byte unsigned integer), Short (2-byte signed integer), Integer (4-byte signed integer), and Long (8-byte signed integer). These types map to System.Byte, System.Int16, System.Int32, and System.Int64, respectively. The default value of an integral type is equivalent to the literal 0.
The floating-point value types Single (4-byte floating point) and Double (8-byte floating point). These types map to System.Single and System.Double, respectively. The default value of a floating-point type is equivalent to the literal 0.
The Decimal type (16-byte decimal value), which maps to System.Decimal. The default value of decimal is equivalent to the literal 0D.
The Boolean value type, which represents a truth value, typically the result of a relational or logical operation. The literal is of type System.Boolean. The default value of the Boolean type is equivalent to the literal False.
The Date value type, which represents a date and/or a time and maps to System.DateTime. The default value of the Date type is equivalent to the literal # 01/01/0001 12:00:00AM #.
The Char value type, which represents a single Unicode character and maps to System.Char. The default value of the Char type is equivalent to the constant expression ChrW(0).
The String reference type, which represents a sequence of Unicode characters and maps to System.String. The default value of the String type is a null reference.
http://msdn.microsoft.com/en-us/library/aa711900.aspx
Comment: Thanks everyone.. My problem has been resolved. Your responses are appreciated.
Answer: The C# language specification states that for value types the default value is the same as the one assigned by the default constructor and for reference types it is null:
So the value types default constructor values are:

For all simple-types, the default
  value is the value produced by a bit
  pattern of all zeros:

For sbyte, byte, short, ushort, int,    uint, long, and ulong, the
  default    value is 0.
For char, the default value is    '\x0000'. For float, the default
  value is 0.0f.
For double, the default value is
  0.0d. For decimal, the default value is
  0.0m. For bool, the default value is false.
For an enum-typeE, the default value    is 0.
For a struct-type, the default value    is the value produced by
  setting all    value type fields to
  their default    value and all
  reference type fields    to null.

http://msdn.microsoft.com/en-us/library/aa691142(v=VS.71).aspx
The string is not a value type.
Answer: Depends on the type of the variable. If the type can be null then it's default value will be null. Nullable types will all start null.

Complex types (String, StringBuilder) = null
Numeric types (int, decimal, double, byte) = 0
Boolean = false
DateTime = DateTime.MinValue (01/01/0001 00:00:00)

You can set an initial value using:

string s1 = "test";
Dim s1 As String = "test"


Tools for merging similar datasets continuously

Question: How do I merge similar datasets, not just once but on an ongoing basis? This seems like a reasonably common problem so I'd be interested if there is a tool out there aimed at this problem, as a guided workflow. Or if any general purpose data tools might suit.
The exact problem I'm trying to solve is to curate a dataset of UK public bodies that is based on a number of existing datasets that change over time. The sorts of issues are:

The names of the bodies vary subtly between the datasets
The datasets all get updates which I'd like to add in regularly.
There are thousands of bodies, so plenty of automation is required to match them, yet manual matching is essential too.
Once it is established that an item needs copying into my dataset, the columns of the source datasets (name, abbreviation, website, etc.) will need to be mapped to my dataset's columns. I might want to do some manual tidying of the values, and not have this overwritten on the next time I 'run' the tool.

I'm very keen to hear other ideas, as the idea I've come up with seems a little esoteric:

Use crowd-sourcing to match up public body names using Nomenklatura.
Write a python script to take each data source, put in the standardized names, change the columns to a standard structure and save the output as CSV.
Keep each CSV in git as the same 'file' but on different git branches. This allows me to merge changes into the master manually, using visual git tools. Git keeps a full record of changes in each dataset and the merge.
Comment: I totally subscribe to your idea!
Answer: OpenRefine (formerly Google Refine) offers nice tools for data cleansing, e.g. correcting slight spelling variations. You can also script all transformations on the data and re-apply them later for updated datasets.
Is this what you're looking for?
Comment: OpenRefine automate really badly. There is client to include JSON generated by refine in python or ruby but I am still looking for strong examples of their usage. See the [Known Client libraries for Refine](https://github.com/OpenRefine/OpenRefine/wiki/Documentation-For-Developers) page for details
Answer: Duplicate reply to a previous question, but you might like this as its all in Python and very easy to automate.
I would like to recommend an alternative that I have found that I prefer to open refine.
https://github.com/datamade/dedupe
It is a very easy to use python program(recommend using in Linux), that provides many custom options to merge your data sets. You are able to decide how each field is compared. I like this feature, because I have some fields where I only want matches to occur when they are not equal, this field being source, and the values being doc1 or doc2. It handles lat/lon, string, and custom compares. The author is very quick to reply to any questions you might have.
The greatest thing I like is it allows you to help train the program, by taking samples of your data and asking you, is this a match? Yes, No, Unsure, or Finished
So even if you don't want to get into the code and make up your custom comparators your able to quickly train the program what you feel is a match or not.
Very easy to install using Python's pip
<code>pip install "numpy>=1.9"
pip install dedupe
</code>
There are many examples of how to use dedupe.
Answer: Topic Maps is a relationship technology -- standardized in ISO13250 -- that expressly deals with the issue of needing to repeatedly merge disparate data sources.
When I say "expressly" I mean it has excellent structures for solving the identification problem we all recognize from interacting with the web and merging two topics that are about the same thing.
Each of the specific issues you cite are handled directly in Topic Maps:

Identity is based on URIs as public subject identifiers, not just names
Deduping is automatically handled by the Topic Map engine
Unlike database-oriented solutions, constant manual tweaking of the data model and identifying disparate sources as being about the same thing are natural actions when working with Topic Maps
Any piece of information can itself become a first-class member of the Topic Map, with any amount of attendant metadata

Ontopia is an open-source implementation of Topic Maps which was previously sold commercially as Ontopia Knowledge Suite (OKS). The Topic Maps community seems to be larger in Europe than in the United States so training and conferences are most easily found there.
Answer: I am currently working a similar project and we went with Talend Open Studio with no regret so far (after 1 year in the project).
Talend offer:

tons of connectors to get your data from any sources
nice data cleaning and transormation components to massage your data
fuzzymatch option (using levenshtein and metaphone) for reconciliation
job can be exported in a shell script and included in a cron job.
Comment: Talend has two solutions and free Open Source and and a paid one (for support, collaboration features and some extra components). Please note that Talend is more complex than Refine and the learning curve a bit longer.
Comment: So similar to Refine, but runs better from the shell automatically, and you have to pay for it?
Answer: There was a talk at TransparencyCamp on cleaning open data that touched on merging datasets.  You can see the notes for the talk here.  The speaker recommends: deDupe, superfastmatch, saucebrush, name-cleaver.  There's also a long list of tutorials for using OpenRefine.
Answer: csv2rdf4lod is a tool designed to integrate multiple versions of multiple datasets from multiple source organizations. It produces RDF and provides a hierarchical URI design that preserves where data elements came from. It uses a unix/shell environment (no GUI) and is focused on server-based automation and replication.
Even if you don't use it, flip through the hierarchical URI design convention. Each dataset "update" that you receive is modeled as a new version and it aligns with the previous versions in One Big RDF Graph depending on how you model the RDF creation.
Best of luck,
Tim
p.s. As suggested, I note that I'm the author of the tool.
Comment: Tim, if you are the author, please disclose that. Otherwise your post will be tagged as spam.
Comment: It would be useful to provide an example where you or others have used this tool and how it worked out.
Answer: Throwing in my weight into this topic. I work on an open-data project to solve producing dataset compilations from multiple dataset sources. We tackle issues like:
language (we handle 6 languages used by UN: en, fr, es, ru, ar, zh)
language script
character encodings and error detection
formal, short, variant and abbreviated name matching
ISO, US (FIPS/USGS/NGA/CBSA) and Canadian (SGC) geographic identifiers
unit handling
data representation, etc
Below is our on-going proposed spec (CUDE):
http://www.opengeocode.org/cude1.1/csv1.1.php
Below are the governmental datasets (500+) we have processed and released using the spec:
http://www.opengeocode.org/cude1.1/index.php
We haven't released the code yet, just the datasets.
Comment: From a quick read of the link, you describe some unreleased tools, that are not intended to be openly licensed, that convert tabular data into your tightly-defined CSV format. It appears to be aimed at a very narrow type of dataset. It's not clear how you describe the schema of a file to be imported. A more helpful answer would actually describe the tool and cover how it solves the difficulties described in the question.
Answer: Google Cloud DataPrep is a great data preparation tool now on beta, pros:

no size limit
GCP integration
great UX
Serverless

OpenRefine offers nice tools for data cleansing, but it's ancient and limiting and in my personal opinion incomparable in awesomeness to DataPrep
Comment: Great, but does it address any of the functionality or challenges described in the question?
Comment: **yep.**
you work against the datasets by creating flows.
There are plenty of automatic inferences of schema mismatching, and solutions recommendation, it's easy to union / join datasets and once you've made "recipes" for each dataset, you can also run the flows automatically.
It's the first time I'm using it as a data scientist and I'm really thrilled.


netCDF does not display properly in QGIS 1.8

Question: I have a netCDF file of fire emissions on a regular grid of 12 km by 12 km grid cells with 200 east-west grid cells by 161 north-south grid cells centered on the continental United States.  The map projection is Lambert Conformal.  I am using QGIS v1.8.  When I open the raster it displays as a very, very tiny raster located in mid-northern reaches of the State of Kansas.  Can someone tell me what blunder I am performing?
Comment: Sounds like a projection error. What exactly is the projection of your grid?
Comment: There are lots of lcc projections defined for Northern America. I wonder how the data can cover the whole US with that. Apart from choosing the right one, there are also some projections in feet instead of metres.
Answer: Perhaps units? The grid seems to be 12km*(200x161)= 2400km x 1932km, while the continental US is closer to 5000km x 2500km.
If "very, very tiny" is on the order of 2.400km x 1.932km, it may be a km vs. m units problem as well.


Choosing os at startup

Question: If I install elementary OS on my pc alongside with Windows 10 by creating partitions manually, will I be able to choose what OS I wanna boot at computer startup?
Answer: Yes, when installing you'll be given the option to install alongside Windows. This will install GRUB, which will let you choose between windows and elementary each time you start.

Choosing os at startup


Computing tabulate intersection in QGIS

Question: I have a base layer of census data in census tracts (polygons). I'm looking to intersect those tracts with a buffer layer but I only want to include those census tracts whose area is over 50% within the buffer.
The spatial query plugin doesn't offer that kind of precision and I can't find an equivalent of tabulate intersection. Is there any way to do this in QGIS?
Answer: I guess one way to do it would be to use the field calculator.
In the QGIS field calculator, you can create a new attribute containing the area of each census polygon. Just open the field calculator and write $area in it, and set it to create a new column with that (let's call it Area1).
Than you can use the intersect tool in the Vector menu on the census layer with your buffer, and on the created (intersected) polygons you do the same thing again. So you get another column with the new area after intersection (let's call that Area2).
Then you can query the intersect layer with SQL using a filter, and exclude all features where Area2 < (Area1 / 2).
There is probably some more straight forward way to do this though, but this should work.
Comment: Thanks hexamon, that sounds like a promising approach, though as you mentioned I hope there is a more direct method of getting the same result.

Computing tabulate intersection in QGIS


Density Altitude and Cruise Performance

Question: Obviously higher temperature than standard and lower pressure than standard (high density altitude) hurt takeoff performance. The wings have less air molecules to produce lift with, and a typical piston engine will produce less power. But does this translate to less range/fuel endurance in cruise? The performance charts of the PA-28 I fly seem to indicate the opposite.
Answer: As you go to higher altitude and the density drops, you end up flying at higher true airspeed to compensate.  Namely, you want to fly at about the same lift coefficient (and thereby the same L/D) independent of altitude.  Since your weight is the same, and $C_L=W/(q S)$, you hold constant dynamic pressure (q).
$q=0.5\rho V^2$  Flying constant dynamic pressure works out to the exact same thing as flying at constant equivalent airspeed -- KEAS.
However, holding constant KEAS with increasing altitude means you're flying at higher KTAS.
The power required for flight will increase -- $P=D V$.  The drag will be constant, but the velocity (here true) is increasing.  Depending on whether you have a fixed pitch or constant speed prop and where you are in its operation, your propeller efficiency might increase or decrease a bit.  Your BSFC might also increase or decrease slightly depending on details of the required throttle setting.
The 'getting there faster' and the 'burning more fuel per hour' cancel out and you end up with pretty much constant specific range (miles per gallon) for a piston prop aircraft (when varying altitude).
However, humans value getting someplace faster, so it is preferred to fly higher.  In fact, aircraft are often operated at slightly faster than the speed for best range -- the extra fuel required is small, but it can come with meaningful time savings.
Answer: Both higher temperature and lower pressure mean lower air density. This will allow the plane to fly faster at the same polar point. The higher temperature will hurt engine efficiency a bit, but the effect on flight speed will outweigh this, so a net gain in true air speed versus fuel flow could remain, depending on propeller characteristics.
Reasoning: To fly at the same polar point, dynamic pressure must be the same. Lower density needs higher speed to keep dynamic pressure constant, so true air speed goes up with the reduction of the square root of density.
The efficiency of heat machines is proportional to the ratio between the temperature difference within the cycle divided by the maximum absolute temparature. However, given the wide spread between air temperature and the highest temperature during combustion, the change in true air speed is larger, so the reduction in efficiency will be smaller than the gain in true air speed. Since your measure of performance is range in cruise (ground covered for fuel burnt), a higher true air speed at the same fuel burn will directly increase range.
Details now depend on your propeller efficiency over true air speed: For a fixed pitch prop it could go up or down, depending on where the speed for best prop efficiency is relative to flight speed. For a constant speed prop efficiency drops, basically eating up the gain in fuel flow over speed.

Density Altitude and Cruise Performance


Magento is not sending confirmation after B2B registration

Question: I have a Magento website that has b2b registration enabled. When I visit the link  www.mysite.com/b2b it gives the ability of registration and after the customer clicks on submit a message pops up that says You will receive a confirmation e-mail. The e-mail never arrives though. Where could the problem be?  Thank you in advance
Comment: check you are configured cron correctly. also check mail are send to spam
Answer: It turned out that I needed to access the admin panel and then Customers->Manage Customers and then Account->Information and then expand the Is Confirmed menu and change it to Confirmed. Also check the box about sending welcome. After that, depending on the Cron, the B2B client receives the confirmation e-mail.


prevent a program from automatically opening on Ubuntu

Question: Whenever I plug in a USB device that happens to have jpeg files on it into my Ubuntu system, a photo album program automatically opens.  How do I prevent this?  I would prefer if a file manager window would open or even if nothing would happen.
Answer: In nautilus, Edit -> Preferences, then the media tab. At the bottom, uncheck "Browse media when inserted." There are other settings in this window that control how programs and devices behave on your system.


How to add hook to the_title() and get_the_title()

Question: I've having trouble with accented characters now if i do utf8_decode() before echoing the title the problem is solved but instead of changing this all over my theme, can't I do this in one place that upgrade proof? I'm not really familiar with hooks but I think thats they way to do it, havent found out how to do it tho.
Comment: You should rather find out why UTF-8 does not work. That is the default encoding, and it should not be changed.
Comment: Yea true but think is info comes from feed and the accented chars are not correctly in there its there uncoded, which means it gets loaded in uncoded so either I change the importer to decode before storing or i change the enchoing, decoding probly better. Which I just did
Answer: The filter for the_title functions is this one:
add_filter( 'the_title', 'f711_title_filter' );

function f711_title_filter( $title ) {

    return utf8_decode( $title );

}


Presentation of Fundamental Group for a Seifert Fibred Space

Question: I am trying to understand how to make sense of the presentation for a seifert fibred space geometrically. I understand that for each exceptional fibre (with index a/b) you get a generator with torsion for the fund grp s.t. the index corresponds to its order. And a regular fibre(which is homotopic to all of the other regular fibres) is a generator which commutes with everything. What I would like to understand is the other generators and the relations between them and how to think about it visually if possible. I am a newcomer to this subject and geometric topology in general so the more details the better. Thanks!
Comment: have you seen http://math.stackexchange.com/questions/65711/fundamental-group-of-seifert-fibred-space-as-constructed-in-hatcher
Answer: Consider (for simplicity) the case when your Seifert manifold fibers over an orientable  surface. Let $\Sigma$ be a genus $g$ orientable surface with $m$ boundary components, and $\frac{p_i}{q_i}$ for $i=1, \dots , m$ a collection of $m$ rational numbers. Let us compute the fundamental group of the Seifert Manifold
$$M= \left( g ;\frac{p_i}{q_i}, \ i=1, \dots , m \right). $$
By definition, $M$ is obtained from $\Sigma \times S^1$ (a three-manifold with $m$ torus boundary components) by Dehn filling. So the fundamental group of $M$ is a quotient of $\pi_1(\Sigma \times S^1) = \pi_1(\Sigma) \times \pi_1(S^1)$ modulo the normal closure of the subgroup $H \subset \pi_1(\Sigma) \times \mathbb{Z}$ generated by the curves of slopes $\frac{p_i}{q_i}$ killed during the Dehn filling procedure (this is because Van Kampen's theorem). Thus in order to obtain a presentation $\pi_1(M)$ we only have to take a presentation of $\pi_1(\Sigma) \times \pi_1(S^1)$ and to add the relations
$$ \text{filling curves} =1.$$
Let's do it. A presentation of $\pi_1(\Sigma)$ is given by
$$\langle a_1, b_1, \dots a_g, b_g, c_1, \dots c_m \ | \ [a_1, b_1] \dots [a_g, b_g]= c_1 \dots c_m \rangle$$
where $c_1 \dots c_m$ are the homotopy classes for the boundary components. In order to obtain a presentation of $\pi_1(\Sigma) \times \mathbb{Z}$ we add to the presentation above one generator more $\gamma$ commuting with all the other generators
$$\langle a_1, b_1, \dots a_g, b_g, c_1, \dots c_m , \gamma \ | \ [a_1, b_1] \dots [a_g, b_g]= c_1 \dots c_m, \ [\gamma, a_i]=[\gamma, b_i]=[\gamma, c_i]=1\rangle$$
Notice that in that presentation $\gamma$ represents the homotopy class of a non-singular fiber. Finally we add the relations
$$c_i^{p_i} \cdot \gamma^{q_i} =1 \ \ \ \ \ \  \ \ \ \  \ \ \ \ \ \ i=1, \dots ,m$$
coming from the Dehn filling operation, and the presentation is done.


First sentence of "De Legibus"

Question: It says "Lucus quidem ille et haec Arpinatium quercus agnoscitur", but shouldn't "agnoscuntur" be used instead? As it says "the grove and those oak trees of Arpinums are recognized(by me)". I'm still struggling with the basics, so maybe I'm simply missing something important here.
Answer: You are correct. If you as a beginner wrote agnoscitur, it would be wrong.
There are two possible explanations.
Grammatical  Sometimes the verb agrees with the nearest subject, and in a perfect passive this might include gender as well as number. Quercus is feminine; so haec quercus is Nominative Singular; so, 'haec quercus agnota est, would be the Perfect.
Figura There is a figure of speech known as 'hendiadys,' in which the subject is described in two ways. 'The grove, and' then more precisely 'the oak tree, is known.'
Wikipedia on Hendiadys gives a Latin example: "There are many examples in Virgil's Aeneid, e.g., Book 1, line 54: vinclis et carcere, literally translated as "with chains and prison" but the phrase means "with prison chains"."
Comment: I'm curious – and maybe this should made into a separate question – whether you think this really could be an example of hendiadys. If the ille and haec were omitted, I'd say 'yes.' But those demonstrative separate the grove and the oak so much, putting them in such different degrees of proximity to the speaker, that it seems strange (to me) to bridge that distance and take them together as single concept. But I admit that, when I've encountered examples of hendiadys in the past, I've never given much thought to how far the 'one through two' approach can be stretched before it 'breaks.'
Comment: wow this is super helpful, they all make sense (I like the second explanation even more), thanks a lot!!!
Answer: How do you know that "quercus" is plural? If it's singular and the grove belongs to someone else (ille lucus = that grove yonder i.e. some distance away, possibly belonging to another) then the one, single oak tree, of the Arpinums, is recognised (= "agnoscitur"). The masculine, singular, nominative demonstrative pronoun "ille" = "that yonder"; as opposed to masc., sing., demonstr., nom., "is" = "that (near to me)". Similarly: feminine, singular, nominative, demonstrative pronoun, "haec" = this", indicating one oak tree; plural form, "hae", would have indicated "trees", plural.
Comment: but I think the sentence is "sloppy" because it's a dialogue, I'll just have to be less fussy about the infection (languages with inflection are scary...), and just read more(as soon as my brain returns from the state of scrambled eggs)
Comment: oops I just assumed it's masculine because of the ending, my bad...that one solved, I think it has to be singular and the verb goes with the closest subject. since later it went "saepe a me lectus in Mario",  so I think he read both about that grove and this tree (otherwise he wouldn't mention the forest). then lectus is used which is even more confusing, cuz by that logic given by Hugh lecta should be used not lectus, lecta can be f.sg and n.pl and they would both work...
Answer: Not necessarily. Like Hugh said, sometimes in Classical Latin, the verb agrees with the nearest noun. You can find examples in Caesar's >>De Bello Gallico<< as well.
Comment: Can you add an example fro *De bello Gallico*? A concrete example would make this point stronger.
Comment: yes so it would appear...it's so cool...and uh...not pedantic as "classical" would sound like...

First sentence of "De Legibus"


Magento 2 SKU not showing on Product Page

Question: Magento 2 SKU not showing on Product Page any one have experienced about this issue i'm using custom theme.
Comment: try to switch to the default theme, if you see the SKU on product page that mean your custom theme not display the SKU for the product and you need to override your theme and modify it
Comment: yes i have the same issue.. luma theme worked fine.. but i'm using AMSport Magento 2.1.6 version..  is their any advice to override it.
Answer: Open file catalog_product_view.xml whci can be found in below directory of your theme : Magento-Catalog\view\frontend\layout\ and find below code block :
<referenceBlock name="product.info.sku" remove="true"/>
if you find that code block replace remove="true" to remove="false" ( or you can delete that line entirely ).


How can I add signatures to Preview.app in Lion without using the web cam?

Question: Is it possible to add a signature e.g. from PDF files or from JPEG images instead of using a web cam? The problem is that I don't have a web cam and I would like to use this feature in spite of that.
Answer: It appears that at present, that isn't an option. When I created a signature file using the FaceTime camera, I see that first of all, there is no unencrypted graphic file created by Preview. Preview did a new key in Keychain titled "Preview signature privacy", suggesting that the signature files go directly from Preview's camera interface to an encrypted file. There isn't a supported way to add a graphic as a signature, and the encryption makes it difficult to bypass the approved new signature process.
Comment: That keychain entry is only a password to decrypt a file, it isn't the image file itself. So there's a file...some place on disk there's a file for the image.
Comment: Good call! Where ever it's hidden, I haven't been able to find it yet, but I'll keep looking
Comment: I also don't have a webcam so I am unable to test it, but perhaps [FSEventer](http://www.fernlightning.com/doku.php?id=software:fseventer:start) would be of some use in locating that file?


Importing shapefile into PostgreSQL/PostGIS?

Question: I'm completely new to PostgreSQL and PostGIS. I finally got both installed and have the PostGIS extension installed. I'm running the PostGIS shapefile import manager. I select my shapefile and click import. It says shapefile import completed but I do not see it in the file in the database. Any thoughts?
Comment: What parameters did you use, a screen shot may be appropriate? Do you have, or have you given, permission to the tool to 'see' the database? RDBMS is not like filesystem data, there's so much more to it, for example did you create a new database using the PostGIS template?
Comment: http://tinypic.com/r/znvt3l/8
http://tinypic.com/r/znvt3l/8
http://tinypic.com/r/n3x7v5/8
http://tinypic.com/r/o8rmgl/8

here are the screenshots in sequential order.
Comment: It is best to edit and insert the image into your question, many users may be unable to go to web hosting sites due to I.T. restrictions.
Comment: **DO NOT IMPORT INTO TEMPLATE_POSTGIS** use that template to create a live database. Do you have PGAdminIII?
Comment: I created that template myself. I don't know what you mean by creating a live database. I tried creating a newdatabase and added the postgis extensions to it. I then tried to import again and it didn't show.
Comment: When you install PostGIS it creates a template_postgis database that you need to use to create a spatially enabled database.
Comment: It didn't do that for me. So I created my own with the same name and added the extensions. It says it's installed when I go the app stack builder.
Comment: Then something went wrong during the install. Uninstall and reinstall PostGIS. The template_postgis is critical to maintaining a PostGIS database.. answer coming soon.
Comment: template_postgis is old school.  At least the windows installer, we no longer install a template_postgis database, since using CREATE EXTENSION postgis; is the new way of installing postgis.
Comment: Chris,  yah what you have looks fine, but did you mean to load the table in your template-postgis or you spatialdata.  Your screen shot shows you had selected template-postgis, so the table would be in there and given templates by default you would make read-only  who knows what that actually did.
Answer: Using PGAdminIII create a database using the template_postgis as a template, this copies all the triggers, functions and tables into a new database. Right click on the databases symbol and select 'new database':

Then you can import data into it. It is probably best to not use the pg_admin user but if you're the only one seeing the database that should be fine. Have a read of Roles and Privileges to see about creating a 'user' or users identity(s).
If you don't have template_postgis in your database then perhaps you can create it (or here) but I found it best (easier) to uninstall and reinstall PostGIS.
Comment: Hey Michael,
Thanks for the help. I installed postgis again and it created a sample database with 7 extensions. I then followed your instructions above. The new database looked identical to the sample database. I then tried to import the shapefile with no luck again. It said it succeeded but it doesn't show up in the tree. alkdjslsjd!
Comment: Are you looking in the public schema? DB=>Schemas=>public=>tables. Perhaps it doesn't like SRID=0 but that doesn't seem likely, not every spatial reference is a SRID. Confirm that you're connecting with PGAdmin as the same user (postgres), it might be there but you may not be able to see it. Also it might help if you have a postgres schema... there was something about that but I don't remember if it's a SDE or PostGIS requirement.
Comment: Both answers are correct above. The shp files were importing but I wasn't looking in the right place. I needed to be in DB=>Schemas=>public=>tables. Thanks Michael


Product filter using attributes

Question: How to filter products shown on the category pages based on the products attributes???
I should be able to filter the products based on the attributes such as manufacturer price color etc shown on the layered navigation menu.
Answer: In the Magento Backend, under Catalog > Manage Attributes, select the attribute in question and set "Used for Sorting in Product Listing" to "Yes".

Product filter using attributes


Will there be problems bringing an ointment that is labelled in grams through TSA security?

Question: I have a prescription ointment I'd like to bring in my carry on when flying next week.  While it is equivalent to 2.11 ounces it is labelled in grams.
All the TSA FAQ's note ounces and ml, not grams, so I worry that I could get flak.
Is there a chance the TSA is going to confiscate this or argue or otherwise delay me?  Does anyone have experience with this?
Comment: those are liquid ounces, not weight ounces
Comment: Do you mean [this FAQ](http://www.tsa.gov/traveler-information/3-1-1-liquids-rule)?
Comment: @KateGregory oh, the pain!
Answer: Since it's a prescription ointment, it's not subject to the 100 ml / 3.4 fluid ounces rules anyway. Have the prescription label on it and clearly readable, and make sure the name matches the name on your boarding pass and in your passport, and you're fine. (This is more than you technically need because the rules just say "medications" but why give a security officer something to argue with you about?)
(I read about a security blogger who brought two separate one-litre bottles labelled Saline Solution and with official-looking labels on them through security. According to the story when questioned why he needed two, he replied "I have two eyes" and that was good enough for them.)
Answer: In my frequent flying experience TSA never bothered to actually check the container size as long as the container looked "small enough" and otherwise didn't deserve attention. They only did that when a container was visibly large.
This is however not a case in some other countries. In Japan Narita, for example,  there they will go through every single one of them, and will throw away anything over 100ml. Lost there a nice shaving cream (109 ml) which flew with me through US and Europe on like seven flights in a row.
Comment: From firsthand experience (well, my wife's experience) at Narita:  If you ask, and have not used your free baggage allotment already, they will bag it up and hand-carry it directly to the airline counter (with your ticket and maybe your passport, too) so it can be checked as a normal piece and sent down the conveyor to the plane.
Answer: I don't know if the TSA also has weight or mass limits but the 3.4-fluid-ounce rule is a volume limit (more-or-less equivalent to 100 ml). In any case, it would seem that the container needs to be smaller than that, by volume. A mass in grams or even in ounces does not directly indicate that.
Comment: @WhyWouldYouUseMyFullName Yes but still by volume, AFAIK.
Comment: I have never had any problem bringing lotions in 100 ml bottles with me. They never looked at the unit. The TSA agents are pretty good at estimating if a container is bigger than permitted. If it can fit in a 100 ml container, you are good. They don't need the measurement on the container.
Comment: Well the rule also applies to gels, etc.
Answer: Based on my extensive experience I would not expect you to have any trouble - as long as the number of on the label is below 100 grams.
Many years ago I found a specific brand of deodorant spray that labels all of their products as being "150ml" or "150ml/100g", with the exception of one particular product which, despite being in the exact same size container, is labeled only as "100g".
I regularly (and I mean at least weekly) travel with a can of this "100g" spray in my carry-on bags, and have traveled to over 30 countries doing do.  Probably one out of ever 4-5 times the airport security staff look at the can as they presume it is over the allowed size (and in some sense of the word, they are correct) - but to date I have never not been allowed continue with it.  I have had a small number of security people who have looked at the can in great detail (including all the fine print on the back) looking for a size other than the clearly-shown "100g" on the front of the can, but they always fail.
I have been told by security staff in some countries that their criteria is that any labels must show below "100ml" AND "100g".  ie, "150ml/100g" is not acceptable, but the exact same size can showing only "100g" is.
Obviously your experience may vary - but based on hundreds of trips through security in dozens of countries, I'd suggest you'll be fine!
Answer: The TSA and other airport security entities are way too dumb to understand that grams and milliliters are different. Example: I tried to leave London a few weeks ago with a 125 gram jar of Marmite. Now, Marmite is an heavy edible paste with a specific gravity of at least 1.5, so 125 grams of it certainly displaces less than 100ml. There was no point in arguing this to the security doof, so I just let him take it.
Comment: @AndrewLazarus It's obnoxiously written but it _does_ answer the question: it says that there might be problems and gives a specific example. OK, it's not an ointment but I don't see how that matters.
Comment: This does not really answer the question. If you have a different question, you can ask it by clicking [Ask Question](http://travel.stackexchange.com/questions/ask). You can also [add a bounty](http://travel.stackexchange.com/help/privileges/set-bounties) to draw more attention to this question once you have enough [reputation](http://travel.stackexchange.com/help/whats-reputation). - [From Review](/review/low-quality-posts/58796)
Comment: Next time take the label off before you go through security.  Then come back and tell us what happened!


FreeIPA DNS issues with AWS

Question: I seem to be having an issue with DNS setup with split horizon/views in R53.  We want to be able to get a copy of the internal zone from R53 from my local FreeIPA servers.  Is this possible?  I have zone forwards setup in FreeIPA so that if you are up in AWS VPC you can query R53.  However I can't do that form my local office.  We are trying to figure out how to get a copy of the internal zone down to my local FreeIPA servers.  From what I have read this is NOT possible since I can't recursively talk to R53.
Answer: It is, of course "possible," to resolve private hosted zones from outside the VPC... but not with zone transfers, since Route 53 does not support zone transfers.  For this to work, you need to be able to query the VPC's built-in resolver.  This can only be done by using a configuration wirh a source IP address that is within the VPC -- the queries have to come from an instance.
The configuration of your on-prem servers would be almost no different than your inside-AWS servers, as far as recursive queries, but the target IP address that they recursively query would need to be an instance inside the VPC that hosts a DNS proxy that sends those queries to the VPC resolver on their behalf.
Assuming you already have a VPN between your premise and the VPC, this traffic rides the VPN to get to the DNS proxy instance.  If no VPN, then this proxy instance could also host OpenVPN to terminate a tunnel from your premise for the queries.
In either event, a pair of t2.nano instances ($5/mo) in two availability zones should be more than adequate for such a workload.
There are also several "firewall" AMIs in the AWS Marketplace that support DNS forward proxying, if you didn't want to roll your own instances to handle the task.
I'm not specifically familiar with FreeIPA, but... thinking about what you say you are already doing... it seems like you might even be able to configure your on-prem servers to forward their queries to the FreeIPA servers inside the VPC, which should then recursively query the records exactly the same way they do for other clients within the VPC... so no additional instance would be needed.
Comment: So currently I have zone forwarders in at the FreeIPA level for all my zones.  The forwarders points to the AWS VPC resolver for that subnet.  So my clients at my local office are NOT resolving the correct information when querying the local name-server.  They attempt to go to the VPC subnet resolver and communication dies.  My only option that I can see is to explicitly put forwarder entries in /etc/named.conf in my local FreeIPA instances.
Comment: You can't use the VPC DNS resolver *directly* from outside the VPC... but you can query a resolver of your own that is inside the VPC.

FreeIPA DNS issues with AWS


What are the differences between Asperger's Syndrome and Schizoid Personality Disorder?

Question: They are specifically listed as two separate disorders in the ICD, but what are the differences between Asperger's Syndrome and Schizoid Personality Disorder?
Since both result in a withdrawal from social situations, the two can seem quite similar to an outside observer; is there any accurate method used to distinguish between the two in a subject?
Answer: Schizoid personality disorder is characterized by a lack of interest in social relationships. However, with asperger syndrome, it's a limited empathy and understanding of other's situations. In other words, asperger syndrome deals with the inability to empathize while schizoid personality disorder deals with apathy toward other's emotions. Additionally, people with apserger syndrome tend to be less withdrawn than people with schizoid personality disorder. People who have asperger syndrome show repetitive behavior and interests, while schizoid personality disorder does not show this fixation toward repetitive behavior. Asperger syndrome is probably genetically linked somehow and is placed on the autism spectrum. However, schizoid personality disorder is not on the autism spectrum. I hope this response helped!
Comment: This is an extremely subtle distinction, if it is indeed a distinction at all. It implies that the schizoid can understand and internally resonate with others' emotions but simply doesn't care about or act on them. However, the definition of schizoid PD includes emotional coldness, detachment or reduced affect, a limited ability to express some emotions towards others, and a reduced or absent ability to feel pleasure. This, to me, looks remarkably like someone who almost completely lacks emotion as most of us understand it and would therefore be unable to empathize.
Comment: Can you add references to your answer?
Answer: This is a very good question. It's true that there might be some problems to differentiate Asperger's Syndrome and Schizoid Personality Disorder, infact, according to DSM-5
<code>Individuals with a Schizoid Personality Disorder shows a pattern of dethachment from social
relationships and a restricted range of emotional expression.
</code>
Moreover, the manual specifies the likeness of symptoms between Schizoid Personality Disorder and Autism Spectrum Disorder but the latter records
a more severely impaired social interaction and stereotyped behaviors and interests.
According to DSM-5, A personality disorder is an enduring pattern
of inner experience and behavior that deviates markedly from the expectations of the individual's
culture, is pervasive and inflexible and occur in two or more of these fields: 1- cognition 2- affectivity 3- interpersonal functioning 4- impulse control
The DSM-5 divided Personality disorders in three Clusters:

Cluster A includes paranoid, schizoid, and schizotypal personality disorders.
Cluster B includes antisocial, borderline, histrionic,
and narcissistic personality disorders,
Cluster C includes avoidant, dependent, and obsessivecompulsive
personality disorders.

Cluster A refers to "Individuals with
these disorders often appear odd or eccentric." They show a bizzarre and strange behavior.
The cognitive and perceptive dimension - dysfunctional in that disorders - has been correlated with an increased activity of dopaminergic system (Siever, Davis, 2004)

With regards to Aperger's Syndrome, DSM-5 folded it into the umbrella of autism spectrum disorders.
To the diagnose is needed:

Persistent deficits in social communication and social interaction across multiple contexts
estricted, repetitive patterns of behavior, interests, or activities, as manifested by at least two of the following, currently or by history
Symptoms must be present in the early developmental period (Not essential for a diagnose of Schizoid Personality Disorder)
Symptoms cause clinically significant impairment in social, occupational, or other important areas of current functioning
These disturbances are not better explained by intellectual disability

References
DSM-5 diagnostic criteria of Autism Spectrum Disorder
DSM - 5 (2013)
Siever LJ1, Davis KL. The pathophysiology of schizophrenia disorders: perspectives from the spectrum
Comment: Thank you for the first sourced answer. +1. I've downvoted the others because of their lack in resources.
Answer: Schizoid Personality Disorder has nothing to do with psychosis.  A personality disorder is an enduring pattern of inner experience and behavior that deviates from the norm of the individual's culture. The pattern is seen in two or more of the following areas: cognition; affect; interpersonal functioning; or impulse control. The enduring pattern is inflexible and pervasive across a broad range of personal and social situations. It typically leads to significant distress or impairment in social, work or other areas of functioning. The pattern is stable and of long duration and its onset can be traced back to early adulthood or adolescence.
Answer: It is difficult to distinguish between these two because tests and criteria are not perfect. Still, one is a form of autism, one is related to schizophrenia, so they should be different. I would look at autistic traits: tendency to see patterns, interest in numbers, inability to read emotions. If these are normal, then probably it is not asperger or any form of autism. As for schizoid personality disorder, there is a question if we are dealing with a disorder or a personality type. If it is not damaging to the quality of life of the person or others, it should not be evaluated as a disorder. There is an introvert personality type which resembles schizoid and is connected with many difficulties in life, but is still not a personality disorder. So make these three distinctions, separate autistic spectrum by its specific signs, then disorder by evaluating if is counts as a disorder (to be treated). If not, it is simply a possibly rare personality type.
Comment: Can you add sources to your answer?
Comment: There is a good discussion of the issue at Scott Barry Kaufman A Call for New measures for Asperger's and Schizotypy, Scientific American, Aug 17. 2011. While is is of schizotypy, not schizoid, the problem is similar. In my answer I do not have good sources to refer to. Assuming that diagnostics criteria, like DSM IV 299.80 are filled for asperger and also schizoid criteria are filled, which can be so, then I would look for


Sharepoint 2013: How do I restore the "All Items" view?

Question: I accidentally deleted the "All Items" view on my SP13 List page.  When I try to re-create it I get the error message "this view already exists." "All Items" does not appear in my dropdowns anywhere, or on the "List Settings" page.  I even checked recycle bin, not there.  Help??
Comment: did you try to create another all item view with different name and then make it default. once it worked then try to change the name of it.
Comment: OK, I resolved this using SP13 designer.  I basically just added "new" to the views and then typed in the original address.  I had to rename the display name in the code from SP13 as well, since the web page kept saying that name already existed.  All the old views were deleted 2 days ago.  The issue seems to be: where is SP13 keeping the graveyard of old deleted view names and links?  This is what needs to be addressed at this point.  Any clue?
Comment: also try to check the both level Recycle bin, this item will show with no title
Comment: What happens when you navigate to the page by manually adding /allitems.aspx after your list name in the address eg https://user.sharepoint.com/Lists/ListName/AllItems.aspx
Comment: Yes I tried to rename it, it gave me an error message.  Currently the view is named "all items2" but the site default for this page is "AllItems.aspx" so all the links on the site are broken. When I navigate to that page I am redirected to the "page not found" SP page.  Same when I type it in manually
Answer: if I delete AllItems.aspx from the designer, I get it on the recycle bin:
/_layouts/15/RecycleBin.aspx
with the name "(no title)" and the origin "Lists/mylistname"
you can also try
/_layouts/15/AdminRecycleBin.aspx
and
/_layouts/15/AdminRecycleBin.aspx?View=2
Comment: I deleted "AllItems.aspx" from SharePoint Designer 2013. When I accessed "/_layouts/15/RecycleBin.aspx" with my credentials I didn't find anything. When I accessed it with "System Account", I found it :D
Comment: I cannot see the deteted view in suggested URL, even with Farm Administrator. What is the trick?
Comment: @Mark typically the problem is either wrong location or permissions. you may be accessing the wrong site. e.g. http://root/site1/site2/site3/_layouts/15/RecycleBin.aspx VS http://root/_layouts/15/RecycleBin.aspx also, if you try to re-create it it should fail, which will confirm it is recycled
Comment: @TiagoDuarte Is it SP2013 behaviour? I just try create a view test123. Then delete it and then re-create with same name. No problem at all and I cannot see it at recycle bin. I perform the test using site collection admin.
Comment: not sure. I guess you may either have recycling disabled in web application general settings (CA) or the method you are using to delete it, deletes it permanently
Answer: For further reference, if you delete/overwrite (good, that this is possible from e.g. Word) your AllItems.aspx view, there are two good possibilities to get you out of troble:;

You have access to SharePoint Designer? Go to your library, delete the faulty AllItems.aspx and create a new view via SharePoint Designer.
Open your library in Explorer View and delete the faulty AllItems.aspx and copy over a fresh AllItems.aspx from another library.

The second method needs some explanation. You can access the WebFldr.aspx view? Great! Use this as explorer view. You can't? Open the library by attaching it as a network share in Windows Explorer (just use the full URL you know already). You need to enable hidden files/folder in Windows Explorer, then you will see the Forms folder. Open another library or create a new one and copy the AllItems.aspx file from the libraries Forms folder to your "broken" library Forms folder.


Why does the Chamberlain have an accent?

Question: In the series The Dark Crystal: Age of Resistance, each of the Skeksis have different sounds in their speech, such as a slight British accent, although most seem to have American accents, except Chamberlain. He speaks with broken English grammar.  Why?  They've been on Thra for a thousand trine, and none of the Gelflings or Skeksis have any accent or speak any other dialect.  And the Skeksis tend to speak mostly within their own kind.  Why, then, the accent?
Comment: Hmm, sorry.  Sifa elder Cadia has a thick British/Irish/Scottish accent, while no one else does.  Another anomaly here, but he does have an accent.
Answer: I assume you've watched the movie...
If you haven't this will be a spoiler..but the movie came out 30 years ago.
Anyways....The Skeksis and the urRu are actually split creatures from an immortal race of aliens called urSkeks. Weird things that we only ever see a couple of at end of the movie. When attempting to use the Crystal they ended up splitting themselves into each respective creature. Meaning the personality and existence of each is a combination or split of the original urSkek. This is the only in universe explanation of why each character is who, or rather why they are. The Chamberlain's counter part urRu likely got the better vocal chords in the deal.
Comment: Closer to 40 years ago.  *sigh*
Comment: Out of univerise, it's likely because those are the actors they got, unlike Ridley Scott or other directors who would painstakingly ensure things match up, Netflix and the Henson company probably think it's good enough...the audience (which is probably generally very young and some traumatised 80's kids now adults) probably don't care enough to notice. They should sound different and not particularly american...and they don't.
Comment: Ok, that makes some sense.  But I noted in my question's comment that Elder Cadia also has a thick UK accent, and also, so does Gurjin and Tolyn.  All of the Gelflings, then, have same/similar accents, except Cadia, Gurjin, and Tolyn.  The urSkeks split, then, wouldn't explain their odd one-off accents.
Comment: It's worth mentioning that Gurjin's father Ordon does not have an accent.  Where did Gurjin get his?
Comment: @AndrewJay Well, it's not hard to imagine people have gained specific accents from the location they're currently at. This is called Foreign accent syndrome, where natives pick up accents from a local they arn't a native of. https://en.wikipedia.org/wiki/Foreign_accent_syndrome

The other possible thing, could be simply that they grew up most of their lives around the Skeksis, or in a different local prior to the series/movie. If I recall correctly, it was mentioned that some of the Gelfing guards only ever lived AT the castle.
Comment: Well said! lol!


Amazon EC2-what is the difference between on demand and on spot instances other than pricing that spot is more cheaper than on demand

Question: i want to the difference between spot and on demand instances. I know there is a price difference between these two but other than this i want to know the differences. Please help me
Answer: Actually there are three allocation types:

on demand - kind of "default" mode. You request an instance, if there is free capacity, you will get the instance. No long term commitment, but once you get an instance, it's yours.  It may happen that you will get a message that there is no free capacity for the specific instance type and AZ (so far it happened to me only once with AWS).

reserved - AWS reserves the capacity for you. You have guarantee that you will get the instance type in the selected region or AZ.

spot instance - it's kind of auction / bidding of unused capacity. You ask for an instance, you provide your maximum price and if there is free capacity and your price is at the current price or higher, you will get an instance. The difference is - if the free capacity is exhausted, or the current price is higher than your maximum bid price, your spot instance is terminated . You can get a termination warning event upfront.
Comment: If the spot instance is terminated, does the ec2 instance stop working until I take action? Do I need to redeploy everything?
Answer: The resources for both are the same, spot instances utilise the spare compute capacity within the AWS availability zone (those that are not reserved or launched on-demand).
Depending on the demand for that instance class in the availability zone the spot price will increase or decrease (even surpassing the on-demand price).
When you use a spot instance you are taking a risk that if demand increases you will lose access to the spot instance (you are given a 2 minute warning before termination). For his reason it is common to use a mixture of on-demand/reserved instances and spot instances so that you can withstand instance terminations.
Commonly in EC2 applications you would use an autoscaling group with a configured proportion between on-demand/reserved nodes and spot instances.
For more information take a look at the Requesting Spot Instances for fault-tolerant and flexible applications documentation.


Make tags [mapping] and [read mapping] synonyms

Question: The topic of read mapping is a sufficiently distinct subset of the more general class of sequence alignment topics to warrant a dedicated tag. However, we should collapse mapping and read-mapping as synonyms.
Comment: Similarly, "mapping" is used often with "QTL mapping".
Comment: Mapping has distinct meaning in other subfields (e.g. family tree mapping and disease mapping). For clarity, we should not use "mapping" just for "read-mapping".
Answer: Yes, having both mapping and read-mapping for the same thing doesn't make sense. However, instead of making them synonyms, I would suggest we only keep read-mapping and get rid of mapping altogether.
In general, tags whose meaning isn't clear from the tag are bad tags. In fact, mapping is a classic example of a meta tag. Briefly, meta tags are those that:

If the tag can't work as the only tag on a question, it's probably a
  meta-tag. Every tag you use should be able to work, more or less, as
  the only tag on a question. Meta-tags, like [beginner], [subjective],
  and [best-practices], are useless by themselves — they tell you
  nothing at all about the content of the question.
If the tag commonly means different things to different people, it's
  probably a meta-tag. In a cruel, ironic twist, the meaning of the tag
  [subjective] itself … is actually subjective. Ditto for
  [best-practices] and [beginner]. Best practices to whom? Beginner by
  what criteria? These tags are impossible to define by anything
  remotely resembling an objective metric. In comparison, the the
  meaning of tags like [java], [c#], and [javascript] are crystal clear
  to all but the nuttiest of nutbags.

As user172818 pointed out in the comments, the term "mapping" has different meanings in different subfields. Therefore, "mapping" by itself doesn't tell us anything useful about the question; it needs to be combined with another tag (ngs, reads or whatever) in order to be informative. Therefore, it is not a useful tag and should just be removed.
The simplest way to remove tags is to just edit the questions that have them. If no questions are tagged with a given tag, the tag will be deleted from the system automatically. If, in future, we see the tag returning, we can ask for it to be blacklisted.

Since there were only 6 or so questions tagged with mapping, I went through them retagged those that were about read-mapping accordingly. However, this question:
probeset to probeset mappings between Affymetrix arrays
is about mapping between different types of affymetrix arrays. Here, I removed mapping and created a new tag affymetrix-arrays. I don't think it would be worth creating something as specific as affymetrix-array-mapping or similar.
The others were all about read-mapping and are now tagged accordingly. The mapping should now disappear and I suggest we let it fade into oblivion.
Comment: @bli cool! Sorry for making you repeat your work, that's never fun :(
Comment: I thought I had added some info about the "mapping" tag, but I see that the "read-mapping" tag did not conserve this info. Or maybe I'm mistaken.
Comment: @bli oh damn! I'm sorry, that's my fault! The info wouldn't be conserved no, the `read-mapping` tag was a new tag, not a synonym so it wouldn't bring in information from elsewhere. I didn't notice you had added information to the `mapping` tag's wiki when I removed it. I hope it wasn't too much work.
Comment: I found the info back in my activity history:
"When dealing with associating sequencing reads to a matching position in a set of reference sequences (typically a genome)."
I'll add it to the "read-mapping" tag
Comment: These few words were not a lot of work :)


League of Legends: How do blind effects work?

Question: How do blind effects such as Teemo's blinding dart and Heimer's grenade work in League of Legends? For example, does it work against an enhanced auto-attack such as Nasus' siphoning strike?
Answer: Blind affects auto-attacks only. Instead of damage numbers, a yellow "MISS" will display instead.
Blind interacts oddly with ON-NEXT-HIT spells, like Garen's Decisive Strike and Xin Zhao's 3-talon strike. The Auto-attack damage is negated, but any spell effect still goes through.
This means, for instance, that Xin will knock your champion up on a 3rd hit, even when he's blind.

"Blind has no effect on Lee Sin the Blind Monk."

In an April Fool's video, Riot joked that Lee Sin was immune to the effects of blind, but this is not the case.
Comment: @FallenAngelEyes - Given that there are *very* few blind effects, I wouldn't say it would be unbalanced. I would counter, however, that having an exception to the rule is very rarely better than having no exceptions to the rule. It makes it easier for the newbies to learn, that way.
Comment: Just to complete you answer regarding the specific Nasus case, Siphoning Strike [Q] is an ability, is not considered auto-attack, therefore blind does not affect it.
Comment: @Raven That's a shame that it's not the case, as it definitely would make sense flavor-wise, but I guess it would be unbalanced. :(
Comment: @Fallen You can flavorfully think of it that "blind" is really just a general sensory blindness, not necessary just eyesight. Same going with Corki's Phosphorus Bomb (which imparts a chance for missing, not full Blind), that kind of a big bang could throw your hearing for a loop.
Answer: For future reference, here's a copy of the lol wiki Blind article:

Blind

The target will miss auto-attacks, incurring the message "Miss" above their attack target.

Blind only mitigates the physical damage portion of an attack, including physical damage sourced from a physical on-hit effect.
Other damage types and effects won't miss. See: On-hit effects.
Abilities that apply on-hit effects will also miss.
Blind is considered a form of damage mitigation. As such, it is applied after Thornmail's passive.

Does not interrupt channeling.
The duration is affected by crowd control reduction.
The effect can be removed by all cleansing effects (except for Mikael's Crucible).
Blind will not affect certain champion abilities.(e.g. Riven's passive Runic Blade)
Champions with Blind: Heimerdinger, Teemo , Quinn and Valor, Shaco (non-champions only)


Can't find Firefox update in Ubuntu Update Manager

Question: I'm using Ubuntu 12.04 and my Firefox version is 14.0.1. Since because of this version I can't install Firebug. So for upgrading it I searched at the Help->About in the browser window, but there is no update option. Then I searched in the Ubuntu Update Manager, and there are listed very many updates, but I didn't find "Firefox browser update". I'm new to Ubuntu, and I don't know how to work in the terminal so I haven't tried that.
Comment: So, why don't you install updates offered by the update manager?
Comment: i just want to upgrade firefox immediately for my work to continue. dont have time to wait for the whole updates to complete. thats why..sir i asked for FF
Answer: To update just Firefox, you could try the following:
<code>sudo apt-get update && sudo apt-get --reinstall install firefox
</code>
I'd recommend installing the rest of the updates at your earliest convenience.
Comment: that worked and now my ff is v26


Best way to add an individual image to pdf form letter

Question: I want to add an individual image to a static pdf.
Like I have 200 individual images and one pdf that is always the same. Then I want to say something like 2 inch top and 3 inch left and then the programm will place the image on this position and in the end I have 200 pdfs. Which software can solve this problem best?
Thank you.
Comment: The answers to this might help: http://graphicdesign.stackexchange.com/questions/12794/use-an-artboard-as-a-template-exporting-multiple-versions-with-an-image-swap If you've got access to Indesign I'd suggest looking into Data Merge with a spreadsheet of 200 file locations (I've not personally used that feature enough to be able to offer a step-by-step though).
Answer: One way to do this is using whatever mail merge functions you might have on hand. In many programs, you can set up the merge to load a variably named graphic in a specific location, and the location is a data field in the merge record.
In windows, an easy way to get the filename(s) and paths is to select the ones you want, hold shift and right click, this will give you a few normally hidden options, one of which is called "copy as path". Then open a text file and paste the filenames into it. Another way is to redirect the output of a directory listing to a text file using the shell.
For the form document for the merge, you set the unchanging pdf as a watermark, 100% size, no blend or fade. When you run the merge, you want to select the option to save each record as an individual document.


What effect is this?

Question: What is the effect called when the person cares about something or someone (they don't know why), but they're trying to convince themselves that they don't care/shouldn't care?
Example -
Alice just met this man. They talked for a bit, but he really didn't spark any feelings. She also doesn't know much about him. He gets severely hurt that night unexpectedly from an accident. She gets worried about him, and she's contacted by police since she's the last person he talked to. Now Alice is trying to convince herself not to care because she doesn't know the guy.
Comment: She is trying to remain ***aloof***
Comment: Disassociation effect
Answer: to detach from TFD idiom
Now Alice is trying to detach herself from caring as she really did not know the guy.

What effect is this?


Why is HV kept open in OC test of transformer?

Question: Why is HV kept open in OC test of transformer? Also, why is LV shorted in SC test of the transformer? (Generally this is preferred - why?)
Comment: What is "HV" and "LV"?
Comment: HV is high voltage side & LV is low voltage side.
Comment: Which is the driven side because transformers can step up voltage as well as step down.
Answer: By definition, an OC test of a transformer is an Open Circuit test.  Why would you connect the HV windings?  The open circuit test primarily is used to determine the core (magnetic) losses of the transformer, as with no load, you don't have to worry about copper (winding) losses.
For an SC test, the low voltage side is shorted in order to measure the impedance of the transformer.  The high voltage winding is connected to a variable voltage supply, and the supply is increased until the high voltage leg reads it's maximum current.  You don't need full rated voltage to achieve full current this way, and it makes it a simple matter to measure the transformers impedance, as well as the actual copper (winding) loss at full load since the magnetic structure of the transformer isn't driven into saturation (or anywhere near it, the magnetic losses are extremely low when a transformer is excited in this manner).
Answer:
Short Circuit

In short circuit test we have to pass rated current through the short circuited side.
Therefore we select High Voltage (HV) side normally for short circuiting, because it's rated current is less and therefore it is easy to short.
Since the winding are short circuited it takes very less voltage to let the rated current flow through the secondary side, i.e., short circuited winding
When the voltage is less, the flux produced due to it, is less
Therefore, flux linking with core, 'phi' is very less
Hence, cos(phi), that is the power factor, is more. This is also the reason for "When we connect watt-meter in SC test it gives us approximately Copper loss only and Iron loss is negligible."

Since, flux linkage is negligible therefore, iron loss is negligible and hence whatever power is consumed, almost all of that is used to meet Copper loss.

Open Circuit

In open circuit test we have to apply rated secondary voltage
Therefore, we generally select Low Voltage side for secondary
In Transformer, Primary Current Ip, is the sum of no load current I0 and the current due to effect of 'load on secondary' I2".
I0 is primary no load current and is approximately 5% of rated primary current, which is very small value
I2" is dependent on secondary current I2 and since, secondary is open circuited, therefore I2 = 0 and this implies I2" = 0
Thus Ip, which is sum of I0 and I2", is very small
Therefore, Copper loss is negligible.
And since we have applied rated voltage, therefore normal flux linkage takes place and inductance of circuit increases.
This gives low power factor and also Iron loss is shown on the watt-meter (approx.)


What are advantages of German public health insurance over private one?

Question: I'm considering switching to private health insurance (PKV) from the public one (GKV). The cost will be lower, and from what I understood I get better service like faster appointments. What are the downsides, why doesn't everyone do it?
Answer: After actually switching to PKV, I've found some critical drawbacks:

You can't switch back easily. In some cases, you can't switch back at all.
If you are married, and your spouse doesn't work, they can't be insured for free like in GKV. Furthermore, their price in GKV will be higher than if they were alone - your income will be used to determine price for your spouse.
Your children can't be in GKV, and private insurance for them will not be free.
Your insurance price will grow as you age, putting you in hard situation if you don't save much for retirement.
You have to send the invoices for each treatment, including simple visits to general practitioner, etc. - these things work automatically without your notice in GKV.

That being said, in my 30es I've actually saved some money and was able to switch back when a child was born. See my answer here for how that worked. I've also got a few appointments faster, but that was not worth the effort of switching back by far. I've had to research and manage the switch like a second job or something.
Answer: The gesetzliche Krankenversicherung (GKV) is supposed to be sort-of-universal, and it acts very much as part of the welfare system. Insurance premiums are based on a percentage of the income, which is contrary to all actuary principles.
As to your question why people stay in, only people who earn more than a certain amount can switch out of this and take private Krankenversicherung (PKV). The limit is well above the average income.
The German health system has certain financial incentives for health care providers to treat as many PKV patients as possible, which makes it easier for them to get an appointment. But if the provider is paid more for a PKV patient than for a GKV patient, that money has to come from somewhere -- and somewhere are the PKV insurance premiums. This difference is obscured by the welfare aspects of the GKV, which also have to be funded.
Summary, if you earn well above the Jahresarbeitsentgeltgrenze, if you have no dependents, or if you expect to leave Germany soon, it might be clever to take PKV. Otherwise, GKV is the safe long-term bet. Your income obviously just went up beyond the limit. Good for you, but how much are you going to gamble that it stays that way?


Meter/ Rhythm/ Time signature

Question: Can someone explain to me what meter is and how to change and control it? Im a beginner songwriting and im not sure if meter refers to feet per line or if it refers to duple, triple, quadruple, simple, or compound concepts. Someone please help me understand meter :/
Answer: Meter refers to the grouping of beats into bars. It is indicated at the beginning of a composition with the time signature. The top number represents the number of beats and the bottom tells us of the note value, which can be whole notes, half notes, quarter notes, eighth notes and so one. Meter can be simple, compound or complex. I

The first line one is a triple meter, which is subdivided into quarter notes, this there are three quarter notes. The second is also in triple meter, so it has three half notes, as the note is subdivided into half notes. The last two are quadruple, and thus, they have three quarter and half notes respectively. Notice, they are simple triple and quadruple as they are in beats of 2, 3 or 4.
Compound meter indicates any meter which is a multiple of 2, 3 or 4

In this picture, as you can see, in 6/8, 6 is a multiple of 2, so it is a compound duple meter. And as you can see, the note is subdivided into eighth notes, and so, 3 eighth notes = a dotted quarter notes. Which makes 6 quarter notes in total. Same for the 9/8, a compound triple  and 12/8, a compound quadruple, have 9 and 12 eighth notes or 3 and 4 dotted quarter notes respectively.
Complex meters abide the same rules, the only difference being they are not really in duple, triple or quadruple like compound or complex meters. They are meters like 5/8. In this case, you have 5 eighth notes in each beat, but it is not a compound meter as it is not divisible by 2, 3 or 4. Same for 11/16. It has eleven 16th notes in each beat, but are not divisible. Those are less common than simple or compound meters.
Comment: Meter is also a concept in poetry, and, given the presence of "feet per line" in the question, it would make sense to discuss that as well to clear up any confusion.
Comment: Sorry, I have no knowledge of poetry. I took a music theory and history class, and that is how I came to know about meter, but and time signature. My knowledge about poetry is next to none.
Answer: To add on to Newbieviolinist's excellent answer, I also want to mention the 'feel' of the music. Meter isn't an arbitrary construct that let's us mathematically divide up the music; it serves an important function in defining how a song sounds.
Consider the following pieces of music, and presume they're at the identical tempo of bpm quarter note = 90:

There are the 12 G notes in each case, and they are played over the same span of time. If you were to play both pieces at the same time, each note would be played in perfect sync: note 1 of the top piece would sound at the exact same time as note 1 of the bottom piece, and so on.
The difference lies in the pulse of the music. In the each piece, a musician would typically play the first beat of each measure stronger than the rest. This note would be played physically louder. So the difference is now:
Top piece:      LOUD soft soft soft...
Bottom piece: LOUD soft soft LOUD...
Not only would the musician playing the piece acknowledge this pulse, but the composer writing it would too. A common pattern in song writing is to play a chord beneath the melody. Often there will be one chord per measure, which means the start of a new measure will be indicated by a new chord. In this way it's not the louder playing of the music that indicates pulse, but a shift in the underlying harmony.
The final way I can think of to conceptualise meter is: "the bit you tap along to". When I am tapping along to pop music, which is very often 4/4, I will clap on the first beat of the measure and tap the next three. Or sometimes I'd clap 1 and 3, and tap 2 and 4, depending on the song. The 3/4 meter is used in waltzes. When I sing a waltz, I sing different beats on different syllables. "DAW da da, DAW da da, DAW da da, etc".
In summary: meter tells you where the strong and soft beats are.

Meter/ Rhythm/ Time signature


Unable to Eject USB Drive

Question: So I have some photos I took from my camera's SD card stored onto a spare USB drive that I have (cause my laptop doesn't have a SD card reader so I just use a roommate's laptop that does and transfer it to my USB drive), and I go to eject the drive after looking at the pictures, but its says its unable to because its still in use. The only thing on that drive are photos, but nothing is open. What do I do?
Comment: I'm voting to close this question because this question have nothing to do with photography
Answer: It sounds like one of two things is happening: either some process still has a photo file open, or the transfer photos to the USB isn't complete (i.e., file copy still taking place, or the filesystem isn't finished the write or write verification, depending on your OS or filesystem).
In the most inconvenient case, simply shutting down the laptop (safely) will allow you to remove the USB drive. If the copy isn't complete, the shutdown might be delayed until the copy is finished. But regardless, if the machine shuts down without errors, you can remove the USB drive, and know that the files are probably correctly written.
If the machine doesn't shutdown normally, or requires a force power off, then you should be concerned about the integrity of the files on the USB drive. Use whatever methods you are familiar with to verify the files are there, and that they contain what you expect them to. The exact method is beyond the scope of this answer (because it depends on your backup & verification practices that existed before this occurred).
Answer: What OS? If you want to be certain of doing the right thing, shut the computer down and then remove the USB drive. If you're using Windows, I suggest freeware LockHunter application that can show you what application has locked your files.
Also, do not keep only a single copy of your photos. All drives fail/die - magnetic and flash-based. Don't wait until it's too late. Back-up now.
And... buy a card reader. E.g. https://www.amazon.co.uk/gp/product/B07HB866XN/
Answer: It can be an open file or an open directory (file explorer window....). In any case, after a couple of minutes the filesystem on the SD card should be in sync and there should be no damage if you remove the card if all files have been transferred.
This said, a USB SD card reader costs a few dollars/euros, and can be much faster than a built-in one: on my PC the integrated SD card reader uses USB2.0 electronics while an external one (basic model from Amazon) in the right port uses USB3.0.

Unable to Eject USB Drive


upgrade Motherboard O.S. to windows 7

Question: Can i upgrade the windows operating system from Windows XP to Windows 7 on Asus Motherboard P5PL2-E,CPU E6300 intel core 2, 1,9 ghz, 1,5 gb ram, 500 gb HD, asus eah5450 series video. If it can the ram will be upgraded to 2 gb (maximum ).
Comment: There is no direct upgrade path from Win XP to Win 7. You would have to start afresh, copy out your important documents before, then back afterwards.
Comment: Three thoughts: 1. You can run Win 7 in 2 GB RAM, but you probably won't be thrilled with the performance.  2. Win 7 is almost end-of-life itself, so you will be paying to replace an EOL OS with one that won't be supported for long.  3. Consider a featherweight Linux distro, particularly one that runs RAM-resident.  You can coax some great performance from an old, minimal system, and it's free to investigate and use.
Answer: Motherboard ASUS P5PL2-E supports supports XP, Vista, 7 and 8.1. The drivers can be downloaded from the official ASUS site
The driver for the graphics card can be found here.
There is no in place upgrade path from Windows XP to any edition of Windows 7. You will have to do a custom install, which involves backing up your personal files, settings and reinstall applications and install Windows 7 native drivers.
I suggest that you create a new partition on the hard drive (you can do it without data loss directly in Windows with Acronis Disk Director or Partition Magic or similar app), put your user files there and only after that start W7 installation from CD/DVD or bootable USB.
When running W7 installation you will be able to format the partition where XP is now installed and continue W7 installation into it, while user data on another partition will remain intact.
Take a note of minimum System Requirements:

1 gigahertz (GHz) or faster 32-bit (x86) or 64-bit (x64) processor
1 gigabyte (GB) RAM (32-bit) or 2 GB RAM (64-bit)
16 GB available hard disk space (32-bit) or 20 GB (64-bit)
DirectX 9 graphics device with WDDM 1.0 or higher driver
Answer: Any computer that can run Windows XP can run Windows 7, but with only 2GB of RAM, Windows 7 will probably not be at its best. If the computer can't handle more than 2GB of RAM, it may be time to replace it with a more capable system. You should also be aware that ther is no longer any support from Microsoft for Windows 7; you should probably get a more capable system running Windows 10.
Comment: Downvoter care to comment?
Comment: The statement "Any computer that can run Windows XP can run Windows 7" is not true. There are motherboards compatible with XP in which there are no Win 7 drivers.
Comment: @Keltari the requester specified the MB model. it supports XP, Vista, 7 and 8.1! The answer above meets the author question though is not fully correct.
Comment: @Keltari - For what it's worth, I've never actually encountered (or heard of) a board that supported XP but didn't have the for 7, though I'll allow that it's possible. If I had, I'd have said "most", not "any".
Comment: @JeffZeitlin I've once been working on a PC that did support XP SP1, but not XP SP2. These two differ way less than XP and Vista or XP and Win7, so I'm pretty sure you could find such a setup that wouldn't work with anything past XP.

upgrade Motherboard O.S. to windows 7


Jamming & linear guiding

Question: For a linear guiding I need to know the concept and understand the jamming limits. See picture. If I choose concept 1 or concept 2, what will be the value of X? How can I calculate this?
Comment: If I use concept 1 then I think jamming will appear very quickly.

Assume the distance F to B = 50 and the angel is 0 degree => Normal Force on point B = F /x
The friction force on the contact point B must be < 0,74 x the Normal force.
X = 50/0,74 = ~ 67,5!

If I use concept 2 the contact on C will result in tilting left turn. Then no jamming will appear.

Is my reasoning correct?
Comment: concept 1- almost, except I think friction from normal force has to be counted in two places. If the R = axis offset distance, N = normal force, and neglecting the angle, then N=FR/X as you have, but F = 2μN because there is normal force in two places, both producing friction in same direction. Thus X=2μR.
Comment: for concept 2, I agree, but the normal force is primarily from Fsinθ, so the jamming condition is μFsinθ > Fcosθ, which is never for small angles. If the force is passing through a point other than the center, it would become interesting
Comment: Because of the extra clearance at C, this is essentially a single cylindrical fit, with offset force. A rough practical guideline is to compare "X" to the distance between the axis of the shaft near A, to how far out the offset load is applied. I.e. if X < 50, very roughly, be wary. Depends much on friction, of course
Comment: more specifically, you can calculate the normal force at A and B, as a function of F, multiply each of those by friction coefficient. If the sum of those products at A,B is greater than F, it jams. The effect of the 10deg angle is usually negligible
Comment: as with anything depending on friction coefficient, use generous safety margins
Answer:
The jamming is triggered by a torque acting on the contact point B.
See diagram. If the distance a < l no jamming will appear.

In concept 1: X = 2.50.0,74 = 74 This is verry large. Adding some bearings will reduces the distance X substantial.
In concept 2: X is, I believe, not relevant.  Since the force is always between the contact points, correcting tilting will appear. To convince myself I have to test this.
Answer: I think the picture below describes the sequence to create a jam, assuming the slots are identical, and perfectly aligned with the posts. This is a simple geometric problem, but without knowing the potential shift towards the left, X couldn't be determined.

Instead, if you know X, you can find the angle of rotation that will create a jam.

Jamming & linear guiding


What is the health of Chess.SE's beta from SE's point of view?

Question: Has there been any comment from SE on their view of the health of Chess.SE's beta, and what is required to exit beta?

Related current stats:
Answer: As far as I am aware, the most recent and most direct comment on the site's health from someone at SE has been Grace Note's answer to an earlier meta question about whether the site could pass beta or should potentially merge with Board and Card Games. In short, her comments largely reflected the information from your graphic above: she indicated that the site overall was in her eyes quite healthy (to the point of recommending against a merger), but that indeed it would need to have significantly greater question volume in order to have a chance to graduate.
In response to that, there has also been some recent meta discussion about how question volume might be increased.
Comment: +1 Thanks, reviewed Grace's answer, and did a quick review of the recent meta discussion too. Possible that I am missing something, though the issue I see is that it appears neither Grace, nor the meta discussion address how to get people to ask more questions (or why they might not be asking questions); meaning all that appears to have resulted was an awareness of SE's opinion, and users talking about how they can post more questions; neither of which in my opinion long-term will fix the issue. If SE is supposed to be the expert, they need to provide more info on how to fix the issue.


Transfer existing ERC-20 to BSC

Question: We have an existing running ERC-20 token on main net whith around 200 holders . We would like to move to Binance smart chain or TRON blockcchain as it offers high throuhput and lower tx fees. How should I approach to move my existing ERC20 to another chain especially balances
Answer: you should probably use a bridge available on zapper to transfer your assets to polygon and then use polygon-bsc bridge to transfer to bsc since there is no direct eth-bsc bridge I think
Answer: or you can just mint these tokens where ether ones are burned.
Comment: This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post. - [From Review](/review/low-quality-posts/56359)
Comment: @FlorianCastelain really?

Transfer existing ERC-20 to BSC