Can not use "pathping" command in macOS

Question: In the Windows I can use the pathping command to tail after the network path, but I can not find this command on macOS.
Is it has another name, such as ipconfig to ifconfig?
Answer: In macOS Terminal, you can use traceroute for similar functionality.
There's also a nice GUI tool called Network Utility that you can use to trace a path of your network traffic (in this example I've traced www.apple.com):

In OS X Mavericks (10.9) and later, Network Utility is in /System/Library/CoreServices/Applications.
In OS X Mountain Lion (10.8), Lion (10.7), and Snow Leopard (10.6), Network Utility is in the Utilities folder of your Applications folder.
Comment: Just a heads up for the OP, tracert does not measure packet loss over time like `pathping` does.
Comment: Network utility has been deprecated in macos bigsur
Answer: The comparable command, mtr, can be installed with a package manager, such as Homebrew. After installing Homebrew, one can install the software as follows.
brew install mtr

If desired, one might also make an alias for pathping. For example, in BASH...
alias pathping='sudo /usr/local/sbin/mtr'

The familiar result is illustrated below.
Answer: Just wanted to say that Christopher provides the most accurate answer here.
Traceroute and pathping are 2 different tools that do the same thing in a different ways. By suggesting traceroute you're suggesting alternative tool and not equivalent tool and thats a big difference. OP is asking for equivalent, not alternative and mtr is the closest equivalent.
As written here: https://networkengineering.stackexchange.com/questions/42886/difference-of-tracert-and-pathping

PING, is an application based on the ICMP protocol which is used to send echo packets to a destination and expecting to receive an echo
response and it calculates the RTT (Round Trip Time) from when the
packet was sent to when the echo response was received. Generally when
using PING on a LAN network you can trust that what it is saying is
accurate unless you have foreknowledge of network devices in the
transit path that prioritize ICMP over mission critical TCP/UDP
Traffic. This however is very common in networks that utilize unified
communications, meaning voice and data on the same network. This is
because QoS Policies are put in place to ensure voice traffic and
other mission critical traffic is prioritized over ICMP thus
indirectly affecting the RTT time of an ICMP ping test.
Trace-route is another method commonly used by technicians and engineers to diagnosis latency in the transit path however any
engineer that has studied how trace-route works would know that its
results are nearly always misleading.
Trace-route works in a manner similar to ping however it uses the TTL feature to make each successive hop in the transit path respond
with an ICMP TTL Expired packet. Thus gives you the ability to
determine which network devices the ICMP packet is traversing.
When you dig deeper into the operation of traceroute you will see that traceroute utilizes 3 probe packets for each successive hop by
default unless you specify other wise. Each probe packet indirectly
measures the latency between the source and the device where the TTL
is declared expired. This latency calculation is a by product of its
true intended purpose. Keep in mind even if you send probes to a
device that is five hops away, random latency spikes in any four
devices prior to the fifth hop can result in the fifth hop looking
like it has high latency.
Pathping works first by doing a traceroute to the destination then it uses ICMP to ping each hop in the transit path 100 times. This is
used to verify latency between the source and destination via icmp
echo per each hop. But remember what I said earlier, you cannot rely
ICMP when public devices are involved. So you can run into cases where
you see ICMP pings destined to one hop in the transit drop 40% of the
traffic whereas the next hop has 100% success rate. This is due to
CoPP.
Pathping in general is a much better tool to diagnosis latency from a specific source to destination with a relative degree of
accuracy. Note that I said Relative, this is because latency is ALWAYS
relative to your location on the network.
Answer: You can also use the Terminal too.
traceroute <ip address>

Also you  could do a ping too.
ping <ip address>

Network Utility is nice in that it wraps all the utilities in one tool.
I'd guess that you could write a shell script which wraps both together which it sounds like pingpath does.
Comment: Honestly traceroute is not same pathping. Mac has already have traceroute and we can track the ping but less informant way.

Can not use "pathping" command in macOS


What is the difference between a Bowden extruder and a direct drive extruder?

Question: As these are the two most commonly used extruder systems in FDM printers, I would like to know what is the difference between them. What are the advantages and disadvantages of using each of them?
Answer: A Bowden extruder and a direct drive extruder are two different types of extruder systems used in FDM 3D printers. Both feed filament into the hotend, but differ in the way the filament is pushed into it. The main difference is the location of the extruder motor relative to the hotend, which results in some pros and cons in the usage of both of them.

Bowden extruder
A Bowden extruder has the motor located remotely from the hotend, usually on the printer's frame. Filament is fed from the motor to the hotend through a Bowden tube. This setup is typically used in 3D printers that require high speeds and accelerations, as the reduced weight of the hotend allows for faster and more accurate movement.

The main advantage of a Bowden extruder is that it reduces the weight of the printhead. It can improve print speed and accuracy, especially for faster print speeds. It also reduces the amount of space required in the printhead, allowing for larger hotends or additional features to be added.
However, Bowden extruders can suffer from problems with filament control, such as oozing or stringing of the filament. The friction in the Bowden tube and distance between the extruder and the hotend causes the reaction time of each motor movement to be extended.

Direct drive extruder
A direct drive extruder has the motor located directly above or beside the hotend, which eliminates the need for a Bowden tube. The Bowden tube is typically very short or totally absent. This setup is used in printers that require precise filament control and are capable of printing with a wide range of materials.

The main advantage of a direct drive extruder system is that it minimizes the distance between the extruder and the hotend. It allows for better control of the filament and reduces friction due to a shorter distance between the extruder and the hotend. This allows to use smaller values of retraction settings, which can reduce stringing and oozing. It results in better control of demanding filaments. Direct drive extruders can handle flexible and soft filaments more effectively.
However, the added weight of the extruder motor can result in slower printing speeds and reduced accuracy during high-speed printing. A heavier printhead can also cause artifacts and ringing on the surface of the prints.

In summary, Bowden extruders are better suited for high-speed printing and have a lower risk of filament contamination, while Direct Drive extruders are better suited for more precise printing and more demanding materials. The choice between these two systems ultimately depends on the specific requirements of the printer and the printing application. Costs also have to be taken into account, because direct drive extruders are relatively more expensive than Bowden extruders.
Comment: Nice Q and A for the knowledge base! I added the tag to the question. Maybe you can add some words on flexible filament (TPU) in relation to these types of extruders? I upvoted anyways, keep them coming!
Comment: Thanks. Yes, something about TPU can be useful. I'll add it in the future.
Comment: To extend this - are there any other configurations for FDM or are these the only two basic designs ?
Comment: It should be mentioned with "Bowden extruders can suffer from problems with filament control" that you hit these problems hard at speeds far below the point where Bowden becomes an advantage over DD due to lower mass.
Comment: I only heard about a hybrid one. It's called [Zesty Nimble](https://zesty.tech).  [Here](https://www.youtube.com/watch?v=m2NXeQZg0U4) is a Teaching Tech's video about it.


My custom fail2ban jail fails to load even though fail2ban-regex suggests that it should work?

Question: I've written a custom jail and filter in fail2ban for logging into my service. The log file is located in /var/log/motion/motion.log and a failed login generates a line like this:
[0:ml1] [ALR] [STR] [Nov 02 11:42:59] handle_basic_auth: motion-stream - failed auth attempt from <ip>

My jail in /etc/fail2ban/jail.local looks like this:
[motion-auth]

enabled = true
port     = 8008
filter = motion-auth.conf
logpath  = /var/log/motion/motion.log
banaction = %(banaction_allports)s
maxretry = 3
findtime = 10800
bantime = 259200

And my filter in /etc/fail2ban/filter.d named motion-auth.conf looks like this:
[Definition]
failregex = \[0:ml1\] \[ALR\] \[STR\] \[.*\] handle_basic_auth: motion-stream - failed auth attempt from <HOST>

When i run fail2ban-regex /var/log/motion/motion.log /etc/fail2ban/filter.d/motion-auth.conf I get a confirmation that my filter does infact function as intented:
Running tests
=============

Use   failregex filter file : motion-auth, basedir: /etc/fail2ban
Use         log file : /var/log/motion/motion.log
Use         encoding : UTF-8

Results
=======

Failregex: 186 total
|-  #) [# of hits] regular expression
|   1) [186] \[0:ml1\] \[ALR\] \[STR\] \[.*\] handle_basic_auth: motion-stream - failed auth attempt from <HOST>
`-

Ignoreregex: 0 total

Date template hits:
|- [# of hits] date format
|  [2640] (?:DAY )?MON Day %k:Minute:Second(?:\.Microseconds)?(?: ExYear)?
`-

Lines: 2929 lines, 0 ignored, 186 matched, 2743 missed
[processed in 1.06 sec]

But when I try to reload / restart fail2ban to add my new filter I get a message like this:
Found no accessible config files for 'filter.d/motion-auth.conf' under /etc/fail2ban
 Unable to read the filter 'motion-auth.conf'
 Errors in jail 'motion-auth'. Skipping...
OK

Does anyone know what I'm doing wrong?
Answer: In jail.conf the filter line should be used with its name, not filename.
Like this:
[motion-auth]
...
filter = motion-auth


Does Search Engine Robot Reads Image?

Question: I have a programmer that told me better not to use image in website as search engine robot wont read it. I told him that if we apply title to the image, it would work as fine as text. I also proposed that using image will give visual advantage as well. I need to know if there is any SEO expert out there can comment on this as i need to propose a intelligent argument to help my boss to decide.
Answer: You and your programmer are both partly right.

Search engine cannot read images = true.

Search engines can only read/index text.  If you have any "important" information on the page that must be indexed, don't put it in an image.  Use text: paragraphs, headings, etc.

ALT text of images can provide information to search engines = true.

The description text of the images do get read by search engines, and will help.  However, how much information can you really put into this description?  Not much, and this isn't meant for that purpose anyway.
Conclusion: Using images is okay.  BUT do not rely on images for any crucial information.  The images should be used to "enhance" the content, rather than replace it.
Answer: Time will come and they will implement optical character recognition (OCR) to their robots and then it would maybe possible to read text from images.

Does Search Engine Robot Reads Image?


Subgradient of function $f_p(\mathbf{A})$ that has as output the $p^{th}$ largest singular value

Question: Suppose I have a matrix $\mathbf{A} \in \mathbb{R}^{n \times n}$.  Let $\{\sigma_1,\sigma_2,.....,\sigma_n \}$ be its $n$ singular values. Calculating a sub-gradient of  its operator norm (largest singular value) is a well known result. Are more general results available i.e can we find the sub-gradient of the function ( of the matrix $A$) that produces as output the second largest singular value, third largest singular value and generally p-th largest singular value ($p=1,2,...,n$). Is it a well posed question at all.
Comment: What do you mean by subgradient of an eigenvalue?
Comment: I meant , if we treat the $p-th$ largest singular value as a function of the matrix $\mathbf{A}$. Once we have a function of the matrix, then we can talk about subgradients of that function. I edited the question to reflect your question
Answer: As an application of the Min-Max Theorem You get
$$\sigma_{j+1}=\min_{x_1,..,x_j\in\mathbb{R}^n}\quad\max_{x\in\mathbb{R}^n||x||=1\\(x,x_1)=...=(x,x_j)=0}||Ax||.$$
As You see for $j=0$ you get $\sigma_1=|||A|||$ where $|||.|||$ is the operator norm. Of course the singular values are numbered in non-increasing order.Here $j=0,..,n-1$. The result can be generalized to ( possibly infinite-dimensional) Hilbert-spaces and compact operators.
Comment: Thank you @Peter Melech. If I understand correctly, the above formulation expresses each of the singular values as  an optimization problem. But does this formulation help us in finding the sub-gradient of function $f_p(\mathbf{A})$
Comment: As far as I understand it [sub-gradient methods](https://en.wikipedia.org/wiki/Subgradient_method) are a kind of methods solving optimization problems and as far as I can see it, these optimization problems, that the Min-max Theorem yields, would be those that one should try to solve by sub-gradients.@Engineer_2018
Comment: Subgradient of a function is a generalization of the concept  of gradient to nonsmooth functions. My question asks how we can calculate one of those subgradients ( as it is a set ). Thanks for the suggestion, I will check if the min max theorem can lead to any subgradients
Comment: Good luck! At least $\{x\in\mathbb{R}^n :||x||=1,(x,x_1)=...=(x,x_j)=0\}$ is convex for $j=0,...,n-1$.
Comment: Thanks a lot.@Peter Melech


Examples of tangent vectors (or vector fields) with values in a vector space (or vector bundle)

Question: Consider following two definitions:

Definition 1. Let $M$ be a smooth manifold, let $p\in M$ and assume that $V$ is a
  real vector space. We will say that a $\mathbb{R}$-linear map
  $w:C^\infty(M)\to V$ is a tangent vector at $p$ with values in $V$ if
  for any $f,g\in C^\infty(M)$ $$w(fg)=f(p)w(g)+g(p)w(f).$$

And we can generalize it to the global objects.

Definition 2. Let $M$ be a smooth manifolds and assume that $E$ is smooth vector
  bundle over $M.$ We will say that a $\mathbb{R}$-linear map
  $W:C^\infty(M)\to \Gamma(E)$ is a vector field with values in $E$ if
  for any $f,g\in C^\infty(M)$ $$W(fg)=fW(g)+gW(f).$$

I think this is a very natural generalisation of tangent vectors and vector fields.

Question. Are there any examples of tangent vectors/vector fields with values in vector bundles which arises in the differential geometry?

Obviously except when $V=\mathbb{R}$ or $E$ is a trivial 1-dimensional vector bundle $M\times\mathbb{R}.$ I am interested if such objects appear in riemmanian, or symplectic, or poisson, or any other geometry.
Answer: The notion of derivation is quite general, and encompasses also the definitions you have stated. One particularly fruitful example in differential geometry is the exterior derivative
$$d:C^\infty(M)\to \Omega^1(M)$$
taking smooth functions to differential one-forms on the manifold. In the terms of your definition 2, the vector bundle $E$ in this case is the cotangent bundle $E=T^*M$ of the manifold.


Apex scheduler - run two schedule jobs at the time

Question: When two jobs are scheduled at the same time, will these two jobs execute at the same time(in parallel) or one after another (in sequence)?
Answer: As you already know, time of execution is not guaranteed. That said, they will each start as close to the scheduled time as the system can manage.
Comment: Let's say we have 100% of the service availability, and two different scheduled jobs scheduled at 12:30 PM. Are these two going to run at the same time? or when one is scheduled the service is not available anymore, therefore, the second job will need to wait?
Comment: It doesn't work like that. You could likely run dozens of jobs at the same time before seeing noticeable lag. But regardless they are not executed *to the second*.
Answer: I actually tested this by creating a 10 second job:
public class TenSecondSchedule implements Schedulable {
    public void execute(SchedulableContext context) {
        Long start = DateTime.now().getTime();
        while(DateTime.now().getTime()-start<10000);
    }
}

Then scheduled it twice:
System.schedule('Job 1', '0 28 10 * * ?', new TenSecondSchedule());
System.schedule('Job 2', '0 28 10 * * ?', new TenSecondSchedule());

And the jobs started and ended near each other:
10:28:00.0 (551106)|CODE_UNIT_STARTED|[EXTERNAL]|01p50000004bz5K|Job 2
10:28:10.12 (10016563991)|CODE_UNIT_FINISHED|Job 2

10:28:04.0 (683372)|CODE_UNIT_STARTED|[EXTERNAL]|01p50000004bz5K|Job 1
10:28:13.60 (10018027330)|CODE_UNIT_FINISHED|Job 1

Note that Job 2 actually started before Job 1, but there were still (approximately) six seconds left on Job 2 when Job 1 started.
Note that this is not guaranteed. In fact, you see that one job was four seconds off of the scheduled execution time (that "executes based on service availability clause"). However, assuming resources are available, they can run in parallel.


Decimate Selection down to a specific vertex count

Question: I have a vertex loop that was produced from a boolean intersection. I was wondering if there's a way, in Edit mode, to decimate the loop from the 50 vertices it is to say, 12 or so. It's not very curvy, it won't lose much shape, just a lot of unnecessary vertices.
Comment: It's a good idea to show a screenshot of your mesh. The first thing to try is to use `X` > *Limited Dissolve*.
Answer: Decimate Geometry
As your question's title - Decimate Geometry is what you're looking for. Both can find in Blender 2.79b and Blender 2.80 beta.
It collapses those selected geometry by the determined parameters, you can always redo this operator in the invoked panel to see which parameter suit for your case.
Select your target geometry in edit mode and with the mesh dropdown > Clean Up > Decimate Geometry

What if I need a beautiful edge loop?
As another answer point out, you could create a circle with desired vertices. Move it to the edge loop you want to decimate, delete the complicated one and join the circle created. And choose both the edge loop of the opened edges, use Bridge Edge Loops operator to connect them.
Answer: I don't have a direct answer for your question but if you only want 12 vertices in a loop, create one, match it up with the original 50v loop (snap to vertices may help), delete your 50v loop, fill up faces to meet your need.


Does iMessage work internationally with only a number?

Question: My friend and I have a sim from say country A. If my friend goes to country B and temporarily uses a sim from country B (I.e. not data roaming with the original sim), can I still use iMessage given that I only have the original number from the country A sim?
Comment: Attempt to send an iMessage to their current number. If the number/contact remains Blue (when starting a new chat) or if the message shows delivered (in an existing chat thread) it would indicate that iMessage is active on the old number. If iMessage is unavailable on the original number, the contact name will change to green (when starting a new chat), indicating that the message will get sent as an SMS, or the message won't get delivered (when attempting to send in an existing chat thread).
Comment: The number from country B would get registered to iMessage. Would you be fine messaging using the new number? If you can add both the numbers from country A and country B into a single contact card of your friend, chats with both the numbers would appear under the same thread in the Messages app.
Comment: Well I only have the current number, and I don't have their iCloud email so I can't contact them to get the new number
Answer: Yes, you can still use iMessage in this case.
The phone number used in country A is registered with Apple's servers, so when you use iMessage to message that number, they'll send the message to the devices logged in to iCloud with the account that has that phone number registered for iMessage.
Your friend can register multiple such numbers, and from the Settings => Messages on his iOS device choose which numbers to actually use for sending and receiving.
If your friend does not want this to be possible, he needs to deregister his phone number from iMessage. He can do that by following this guide from Apple.
Comment: So that would mean plugging out a SIM card and replacing it with another one won't automatically de-register the former contact number from iMessage?
Comment: No, not as far as I know - that haven't happened for me. Apple details that you need to disable iMessage on your iPhone to deregister (or alternatively use their web form). I have updated my answer to include a link that details how to deregister. Just popping out the SIM-card doesn't deregister the phone number.
Answer: Your situation is similar to "my contact switched to Android, but all of my texts are continuing to send via iMessage rather than SMS":

Contact switched to Android; how to send texts instead of iMessages?
How do I disable iMessage for a contact who no longer has an iPhone
https://selfsolve.apple.com/deregister-imessage/

In your case though it's a positive. iMessage delivery will continue until/unless your contact deregisters their number from iMessage — even if they swap SIMs.


UV mesh is distorted, not a reliable representation of the model?

Question: Im working on a face model, trying to create a single 2d printable image of the face's texture.
I created the desireable uv layout, used the texture paint tool- stencil brush in order to create the texture.
Now, after printing the result, I realised that the UV layout that the Blender created does not represent the model in the correct way. I know that after realising that the both parts of the same seams are significantly not in the same size, although these lines are the line in the 3D model.
I realised that there are two kinds of UV unwrapping methods, but I couldn't find any information on the subject, not in stackexchage and not on different manuals on the net.
What is the cause of this distortion? Can the UV unwrap setting fix it?
Thank you in advance
Comment: It's a little difficult to tell what you're asking. Are you asking "Why is the UV layout on the left different from the UV layout on the right?"
Comment: @D Brown: uv mapping scope is to represent in 2d what is in 3d, so sometimes some faces can look distorted in 2d,  and if you already painted you model, the distorted texture in 2d looks "different" from what you see in 3d. But the point is that once that 2d texture is mapped back on 3d, it will look as you intended, while painting it. Just paint on the 3d texture, not on the 2d texture. And, adding seams can help to prevent distorting
Answer: Look at the paper model export add-on, it seems to be exactly what you're looking for.
Answer: i think your going into a wrong workflow.
If you got the face model.
use seams, to to cut areas for a 'reasonable'fitting UV layout.
So you could split in a front and back, and left / right.
and make seam for example around the ears so they wont distort the unfolding.
Next inside blender create a new image as texture, use blender to paint the texture, and make sure to save your texture.
UV layout are not like origami layouts, but i believe there does exist an adon so you could manually fold a face, but not sure why you would need that.


How does one find out the file system / directories structure of a webserver they don't own?

Question: How does one with simple access rights find out the remote host directory structure? I see that web archives are able to not only backup content on the specified domain, but every folder within it.
Comment: How is the question related to information security?
Comment: @DeerHunter I asked here because of http://discuss.area51.stackexchange.com/questions/18645/hackoverflow-will-not-be-moving-to-private-beta
Comment: Not sure I get your drift here. This is a basic question for SuperUser/Unix&Linux SE's, and you would have to specify the OS.
Comment: Is your question only in the context of web servers where the attacker is a normal visitor?
Comment: @Philipp Yes, where the user doesn't use tools.
Answer: Web archiving tools are usually so-called "Spiders". They start with a HTML document and then follow every link they find on it, then search for links in these documents and so on. That way they are usually able to find any file on the webserver which is linked from somewhere on the same domain. The <a rel="nofollow" attribute on a hyperlink is supposed to prevent spiders from following links, but keep in mind that it is only a request the spider doesn't necessarily follows (The webspider I wrote once didn't, just because I was too lazy to implement it).
Search engines don't just spider a single domain but also follow links leading to other domains, so they sometimes manage to find files on domains which are not linked anywhere from that domain, but are linked from other domains. This can be prevented by using a robots.txt to deny indexing of directories you don't want to appear in search engines. Again, this is just a polite request for search engines, not an effective security measure. However, most search engines will respect it.
Some webservers are configured in a way that when a visitor requests a directory, the webserver generates a listing of all files and directories in there. However, this becomes quite rare because it is usually not what the webmaster wants. Nowadays most webservers are configured out-of-the-box to return 403 or 404 instead of a directory listing.
When a file is not linked from anywhere explicitly and the webserver doesn't intentionally provide some way to list directory contents, the only way is to guess filenames. Some penetration testing tools will automatically guess names of files which might be interesting to an attacker (like /wp-config.bak in case the webmaster did a backup of their wordpress configuration and forgot to protect it against public access). But brute-forcing every possible filename is too slow to do it online, so that method won't get you every single file either.


Number of Wi-Fi channels to be used?

Question: Under advanced wifi settings one can change number of Wi-Fi channels to be used (11, 13, 14). Does anyone have a clue on how does this property affect battery drain? I know it should be configured depending on how your Wi-Fi router is set-up, but maybe one number of channels should be ("defaultly") preferred over another so battery would last longer?
Answer: It has nothing to do with battery life; the number of channels is a regulatory issue (for example, in the US, only 11 channels are allocated for 2.4GHz Wi-Fi).
Technically, Wi-Fi is frequency hopping, so the "channel" is a center frequency around which the actual transmit frequency skips.  You can't disable that; it's part of the channel sharing arrangement (Wi-Fi would be unusable if every client on the channel transmitted on the same frequency).  And beyond that, which channel your device uses is determined by what AP you're associated with, so you have no control over it.
Comment: @pootzko: that certainly happens, but (a) you still need to change the AP to accomplish anything and (b) adding channels means using someone else's spectrum which is (a) illegal and (b) quite possibly worse (consider what might already be using those addresses; they're not restricted just to annoy people, they're given to someone else).
Comment: Also note that there are additional tradeoffs: a closer AP may be more congested, requiring more transmissions, but may use less power overall than talking to a less congested but more distant AP. (Most WiFi cards do reduce their transmit power when they can; on Linux you can often determine the current transmit power using the wifi tools.)
Comment: @pootzko On a related note: channels 1, 6, and 11 provide the least interference.  Wikipedia has a good explanation if you're interested in why.
Comment: a bit unrelated, but could it be that if lot of devices are connected to a wifi router, they congest the channels and than that is what in the end drains the battery more than it should because more packets have to be re-sent?

Number of Wi-Fi channels to be used?


Is the unit Millirem the same as Milliroentgen?

Question: Are millirems the same as milliroentgens ? When I search google I found many helpful  conversion charts and they all say the following. 1 Rad = 1 Rem but .86956  millirem is 1 milliroentgen. How is this possible?  Assume  1 apple = 1 orange then 1/1000 of an apple = 1/1000 of an orange.( Let's not worry about the apple stem.)  One of my dosimeters is measured in milliroentgen's and the exposure charts are in millirems. Should I convert  or use tit for tat?
Comment: i am not qualified to give advice on that, since it is healthcare-related. I guess you don't have or can't google manual to the dosimeter? In fact I would suggest asking on health.stackexchange.com
Comment: what are your sources? http://hyperphysics.phy-astr.gsu.edu/hbase/Nuclear/radrisk.html#c1 seems to indicate that Rem is not same as Roentgen
Comment: To answer your question I used google.....but in any event  I accept your answer.  Can we  assume 1 Rad = 1 Roentgen?  That will help but it looks like I will need to make the conversion. I am interested only in gamma sources.  I have two dosimeters , one at 200 milliroentgen and the other at 20 roentgen.
Answer: I don't know where you get your information, but here some quotes and sources.
First of all, US Nuclear Regulation Commission puts it this way:

...dose equivalent (in rems) is equal to the absorbed dose (in rads) multiplied by the quality factor of the type of radiation

This link shows difference between Rem unit and Roentgen unit. Namely, Rem is unit "biologically effective dose" and Roentgen is unit of "Intensity" of the source.
Quotes:

The roentgen (R) is a measure of radiation intensity of xrays or gamma rays. It is formally defined as the radiation intensity required to produce and ionization charge of 0.000258 coulombs per kilogram of air

And (emphasis mine)

The biologically effective dose in rems is the radiation dose in rads multiplied by a "quality factor" which is an assessment of the effectiveness of that particular type and energy of radiation. For alpha particles the relative biological effectiveness (rbe) may be as high as 20, so that one rad is equivalent to 20 rems. However, for x-rays and gamma rays, the rbe is taken as one so that the rad and rem are equivalent for those radiation sources.

Wikipedia notes:

...1 roentgen actually deposits about 0.96 rem in soft biological tissue, when all weighting factors equal unity. Older units of rem following other definitions are up to 17% smaller than the modern rem.

I think main confusion is between biological effect (chance of cancer development) and matter ionization by radiation. They are linked but used to be calculated differently.
Comment: Radiation units are some of the most complicated and messy systems coined by humans. But, the heart of the matter is what you point out - on the one hand the energy in the radiation, on the other the effect on the human body.
Answer: The Roentgen (R) is a measure of air ionization ("exposure"): This measurement is easily accomplished using a GM tube (an ion chamber operated at a voltage putting its operation in the Geiger region) and survey meter as long as the energy field being measured is uniform.  It can also be measured with an electrometer attached to an ionization chamber.  The primary advantage of this quantity is the ease of measuring it electronically. This was the method pioneered by the Curies, and it is still in use. SI units are coulombs / kg air. Customary unit is the Roentgen (R), which equals 0.00026 C/kg, and its subdivisions (such as mR).  Importantly, this measure is only valid for ionizing electromagnetic radiation (photons), not ionizing particulate radiations (e.g., alpha, beta, neutron, etc.).
Absorbed dose: Dose, in ionizing radiation measurements, means the amount of energy deposited locally by radiation in a given mass. This can be measured directly in some instances, such as by calorimetry, but it is more often calculated from ionization current and electronic properties of the detection medium. The SI units are joules / kg, which is given the special name of Gray (Gy). A common customary unit is the rad (100 ergs / g or 0.01 Gy).
Here is where you may be getting confused, as for convenience, it is commonly assumed that exposure and absorbed dose are the same when expressed in traditional units (i.e., 1 R = 1 rad).
Comment: Thank you Radochemist ...yes that clears the confusion very nicely ....I guess that goes to show that high energy gamma is so penetrating that absorbed vs. ionized become one and the same so there is no need to monkey with the traditional units and cause more confusion.


Have the recent Linux kernel USB vulnerabilities found by Andrey Konovalov been patched?

Question: Have the Linux USB drivers been patched for the recent vulnerabilities that have been found by  Andrey Konovalov (Google)? If not what can be done to protect against these attacks other than avoiding use of USB devices?
Comment: There's a complete list of these vulnerabilities [here](https://github.com/google/syzkaller/blob/master/docs/linux/found_bugs_usb.md). Quite a large amount of them have been fixed according to this list.
Comment: @Sonickyle27 So the 14 new vulnerabilities have not been patched yet, if I am correct.
Comment: Only denial of service vulnerabilities have been released, code execution haven't. In any case don't stick unknown stuff in your computer (holds for more than just computers though).
Answer: You can check yourself. Choose a random CVE - I chose CVE-2017-16538. It states -

drivers/media/usb/dvb-usb-v2/lmedm04.c in the Linux kernel through 4.13.11 allows local users to cause a denial of service...

Now have a look at that file history in the repository -
https://github.com/torvalds/linux/commits/master/drivers/media/usb/dvb-usb-v2/lmedm04.c
<code>Aug 20, 2017 media: rc: rename RC_TYPE_* to RC_PROTO_* and RC_BIT_* to RC_PROTO_BIT_*
Jun 24, 2017 media: dvb-usb-v2: lmedm04: remove unnecessary variable in lme2510_st…
</code>
So no - it doesn't look like that one has been fixed. As /u/Sonickyle27 showed many of them do have fixes but it looks like they haven't been accepted and merged yet.
Saying this there is technically the possibility distributions may have patched it themselves.
Comment: How would I know whether the distribution that I am running has the vulnerability or not ? I am asking because you clearly stated that fixes are available but they are not merged yet.
Comment: @ng.newbie - if its not critical and its not merged into the main kernel yet then the chance of a distribution taking its own action is extremely slim. If you want to know for certain then you'd either have to check your own distributions source (and that your system is fully patched / rebooted since they were applied) or test for the vulnerabilities yourself.
Comment: @ng.newbie - Most of these on top of only being known about for a couple of weeks also rely on malicious devices (i.e the device itself - not just whats stored on it). So unless you are state actor level (in which case you really shouldn't plug any device into your system unless you know the full manufacturer chain) the chances of someone handling you a device designed to exploit this in the immediate is close to zero.
Comment: tell me something are these vulnerabilities marked as non-critical ? it shows a CVSS Base Score as 7.2 High.
Comment: @ng.newbie - Without looking at each and every one I can't answer that. If you want that level of detail go and do it yourself! Many have already been fixed. The fact that these require physical access and most lead to something like Denial of Service etc. have me at the view they are not close to critical.


Is it good to tell awakening stories?

Question: My question to all my dear friend is why people use to share there stories of awakening ?
will it affect the mind of others those who are meditating to find the inner peace.
Comment: Yes!...........
Answer: I think at times it can be helpful, and at times, harmful.
The teachings of the Buddha are his experiences. By sharing his atainments, he helps us all walk the path.
Unfortunately, if you are too descriptive, people will seek your experience in their practice. They may come to false conclusions that make guiding themselves toards the next attainment much more difficult.
I think it may be more helpful to others if someone with attainments focuses on another's practice, and asks them to answer questions that spark introspection that leads them toward their next fruition.
Answer:
The hand in the rock is not for the master.It is for the student.

When Milarepa's disciple saw his master do something that tradition and other teachers said could not happen, it helped him break through his beliefs about what is possible. He saw his teacher's mastery with his own eyes. And because he witnessed the miracle personally, his experience told his mind that he wasn't limited or bound by the "laws" of reality as they were known at the time.
Marpa occultly manifested himself in the forms of Gaypa Dorje and other of the tutelary divinities of the Kargyutpa sect and also other divine shapes and forms along with the various symbols associated with each deity such as bells, gems, lotuses, swords, etc. He then explained that these were various psycho-physical powers obtained after enlightenment and that they should never be manifested for an unworthy cause. This was his parting gift to Milarepa, and this, his spiritual son, greatly exalted in his heart to see that his Guru Marpa was veritably a Buddha himself.
He vowed that he himself would gain such powers and show them in his turn to his own disciples. Marpa then told him that he could now depart since he had demonstrated the mirage like nature of all existing things. He instructed Milarepa to meditate in various caves made holy by previous saints in the locale of Mount Kailas, Lapchi Kang (Mt. Everest), and other sanctified places. He then gave to Milarepa a sealed scroll that was to be opened only on dire threat of imminent death. With great sadness, knowing they would not meet again in the present life, Milarepa took leave of his beloved Spiritual Father and Mother with the thought that they would all meet again in the celestial realms.                         Source:Milarepa of Tibet

Is it good to tell awakening stories?


Do I need to worry about increase in temperature/pressure in ultrasound cleaner?

Question: I'm building an ultrasound cleaner. The main chamber is filled with water and it is heated. The chamber is completely sealed so the pressure inside increases with the temperature. An ultrasound emitter will be added to the bottom to increase cleaning effectiveness. Do I have to worry about the temperature/pressure increasing considerably inside the chamber because of the added ultrasound energy? Are the cavitation bubble's effects localized do the bubble itself or should I expect a considerable increase in pressure/temperature inside the chamber?
Answer: If the vessel can go above 15psi, you will need a pressure relief device. This is the case for any pressure vessel irrespective of the ultrasonic consideration. A standard water heater pop off will probably work fine provided your vessel is rated for that pressure.
Most ultrasonic cleaners run at atmospheric pressure. There is no real reason to run at higher pressure unless you are using a solution other than water and don't want it to evaporate.
Heat addition can be calculated from power input. For example if the unit is 12vdc at 2amps it will add 24watts of heat to the system. Your ultrasonic piezo element will have a maximum design temperature. You will need to keep below this temperature by either cooling the piezo element or the whole vessel.
Comment: I don't understand how your answer answers the question. Are you saying that there will be an increase in temperature that will be equivalent to the power input of the ultrasound emitter?
Comment: Correct, 100% of the energy input will eventually become heat.
Comment: @gummibear: ...plus there's no good reason to keep the chamber completely sealed. There are special cleaning solutions, but they don't require sealing, and with normal use, will need to be replaced (saturated with whatever waste product you wash off the items cleaned) long before it drying up becomes an issue. It also contains a temperature regulator; cooling is handled through standard conduction/convection through walls to ambient air, so it only has a heater to keep the temperature optimal.


Why has Boeing used mini winglets on the 737-200?

Question: I found mini winglets just in B 737-200. What's the differences between mini winglets and the blended ones which Boeing uses in more recent versions?
(picture source)
Answer: When originally Richard Whitcomb of NASA developed the winglets, he developed the split winglets with one above and one below as shows in image below:

The one above starts at 0.4x chord from the leading edge. For a test program on KC-135 tanker, which I suppose was first application of the winglets, they used the type of winglets shown in the question:

Conceptually there is no difference in the "mini-winglets" and the "Blended winglets" While I think almost all the wingtip shapes are more or less of same efficacy, I can think of couple of reasons for variations seen among various aircrafts - One is patents taken for some shapes would force other OEMs to come up with different shapes. Second is weight of the wingtip vis-à-vis the reduction in fuel burn. Typically winglets reduce fuel burn by ~3-8% but in some cases, the increased weight can off-set majority of the fuel burn or even prove to be more than compensating for it, especially on shorter hauls. One may be able to make a lighter blended winglet using co-bonded, co-cured composite structure as compared to the short winglet mentioned in the picture which with say bolted joints might end up heavier. I think it would be difficult to say make any generalised comment on this.
Answer: Boeing 737-200s are comparatively old and the winglets developed for them are not by Boeing, but by a third party, as noted by b737.org.uk:

... 737-200..., fitted with mini-winglets. This is part of the Quiet Wing Corp flap modification kit which gained its FAA certification in 2005.

The other types of winglets in B737s- blended wing winglets in 737-800s, the AT winglets in 737 MAX and Split Scimitar in NG 737 (through there is some overlap here) were all developed by Boeing (with others) and are available from production units and also as retrofit.
Comment: While this is a fair remark, I feel it doesn't answer the spirit of the question - why are these winglets so small ?
Answer: Adding winglets to an existing design puts stresses on the existing spar ends that they weren't designed for. Fortunately, they're stronger than may be necessary at the ends due to mechanical implementation requirements, allowing some additional load. But a "full size" blended winglet should be designed in from the start to ensure sufficient strength, minimal weight and avoidance of aeroelasticity (flutter).
Comment: Yet there are extensive full size winglet upgrade programs for existing aircraft. And if you start with the design there may be much better options than winglets. They are beneficial for existing wings because they can deliver a slight wing extension while their weight relieves the root bending moment, and yes the wing/winglet combination needs to be tested for adequate strength and aeroelastical stiffness.
Comment: One story I've heard is that additional load due to winglets was not a problem, as the wings were slightly over-dimensioned initially due to larger uncertainties in the stress calculations. Over time, stress calculations methods improved and some strength margin was found which could be used to handle the additional load of the winglets.
Answer: The mini winglets require fewer modifications on the wings, and the -200 being much older does not warrant large investments in fimproved fuel economy.

The pic above, from this Boeing article on the NG winglets, shows the work required for winglet retrofit, based on stress analysis at ultimate loads in various aircraft states. The winglet shape basically extends the wingspan (but the weight helps to reduce the wing root bending moment), and creates aerodynamic lift and thrust as presented here.
The large winglet on the 737-800 is the result of a large and costly engineering effort, very particularly matched with the wing properties and the payload/range mission of the aeroplane. To make such a design effort for the -200 with its much higher fuel burn rate would be cost prohibitive.
Wiki Commons pic source
The small winglets on the -200 pick the low hanging fruit of fuel burn reduction by reduction of wing tip vorticity. Same as the original winglets on the A320, from before they offered the Sharklet as an improved option. The deleted answer from @FeliceGraziono is correct:

Being smaller, they impart less efficiency but also stress the wing root less.


Can we trick Python for Cygwin as being on the win32 platform? (to install PyBluez)

Question: I want to use the Python packaged with Cygwin on Windows. I need to install PyBluez, a Bluetooth Python binding. I installed it with easy_install, no problem. I know that it works well with the Windows version of Python as I did the .exe install of PyBluez and made some tests.
However I do not want to use the Windows version of Python, but the one from Cygwin. But actually, the installation with easy_install or directly from the tarball does not works well (no error messages, but it is not fully installed). The reason seems simple: in several files, there are some conditional statements:
if sys.platform == 'win32':
...
elif sys.platform == 'linux2':
...
elif sys.platform == 'darwin':
...

Unfortunately, when I launch Python for Cygwin, the platform is:
$ python

>>> import sys
>>> sys.platform
'cygwin'

What is interesting to check is which platform we have when we launch Python for Windows from Cygwin:
$ /cygdrive/d/Programs/Python26/python -i

>>> import sys
>>> sys.platform
'win32'

We could have the idea of modifying some Python files in the PyBluez library so they could take into account both 'win32' and 'cygwin':
if sys.platform == 'win32' or sys.platform == 'cygwin':
...

Unfortunately, 1) it means modifying some files, and 2) it is not enough: in the case of PyBluez, when I import the library, we have in the __init__.py file:
if sys.platform == "win32":
    _dbg("trying widcomm")
    have_widcomm = False
    dll = "wbtapi.dll"
    sysroot = os.getenv ("SystemRoot")
    ...

os.getenv("SystemRoot") is correctly defined when launching Python for Windows, but is not defined with Python for Cygwin.
So, my question is: is there an easy way to trick Python for Cygwin in thinking it is launched from a win32 platform, with all the correct needed environment, without having to modify library setup files by hand?
Maybe it isn't possible at all? (Both version are on Windows, but they are compiled differently).
The question is not restricted to the installation of PyBluez, but also for other kind of libraries.
Answer: I had a similar problem and succeeded in tricking python to do this by adding to the first python file in my app, e.g. init.py or similar
import sys
sys.platform='linux'

Not sure if it will work for you, but something to try


Parametric circuit to prepare the most general single-qubit state

Question: I am highly confused with this statement and spent a lot of time understanding it.
Comment: Would be able to link where you found/saw this statement, so we can have more context for this?
Answer: Let $\rho$ be an arbitrary single-qubit state. Since $\rho$ is Hermitian it has real eigenvalues and an orthonormal eigenbasis in which it is diagonal
$$
\rho = \lambda_1 |\psi\rangle\langle\psi| + \lambda_2 |\psi^\perp\rangle\langle\psi^\perp|
$$
and since it has unit trace $\lambda_1 + \lambda_2 = 1$. Thus we can find an angle $\beta$ such that $\lambda_1 = \cos^2\frac{\beta}{2}$ and $\lambda_2 = \sin^2\frac{\beta}{2}$. The first eigenvector can be expanded in the computational basis as
$$
|\psi\rangle = \cos\frac{\theta}{2}|0\rangle + e^{i\phi}\sin\frac{\theta}{2}|1\rangle
$$
and the other one is fixed up to global phase by orthonormality
$$
|\psi^\perp\rangle = -\sin\frac{\theta}{2}|0\rangle + e^{i\phi}\cos\frac{\theta}{2}|1\rangle.
$$
Thus, we see that $\rho$ is completely described by three parameters: $\beta, \theta$ and $\phi$.
Now, recall that
$$
R_Y(\theta) = \begin{pmatrix}
\cos\frac{\theta}{2} &-\sin\frac{\theta}{2} \\
\sin\frac{\theta}{2} &\cos\frac{\theta}{2}
\end{pmatrix} \\
R_Z(\phi) = \begin{pmatrix}
e^{-\frac{i\phi}{2}} & 0 \\
0 & e^{\frac{i\phi}{2}}
\end{pmatrix}
$$
and so
$$
U(\theta, \phi) = R_Z(\phi) R_Y(\theta) \equiv\begin{pmatrix}
\cos\frac{\theta}{2} & -\sin\frac{\theta}{2} \\
e^{i\phi}\sin\frac{\theta}{2} & e^{i\phi}\cos\frac{\theta}{2}
\end{pmatrix}
$$
where $\equiv$ denotes equivalence up to unobservable global phase. We see that $U|0\rangle = |\psi\rangle$ and $U|1\rangle = |\psi^\perp\rangle$.
This means that we can prepare a qubit in the $\rho$ state by first initializing a data qubit in the $|0\rangle$ state, applying $X$ gate with probability $\lambda_2$, applying $R_Y(\theta)$ and finally applying $R_Z(\phi)$. In practice, we can realize the probabilistic $X$ gate using the CNOT gate targeting the data qubit and controlled by an auxiliary qubit prepared in the state $\cos\frac{\beta}{2}|0\rangle + \sin\frac{\beta}{2}|1\rangle$. The preparation can be performed using $R_Y(\beta)$. After the CNOT gate the state of the two qubits is $\cos\frac{\beta}{2}|0\rangle|\psi\rangle + \sin\frac{\beta}{2}|1\rangle|\psi^\perp\rangle$. Finally, we discard the auxiliary qubit leaving the data qubit in the state
$$
\mathrm{tr}_1\left[\left(\cos\frac{\beta}{2}|0\rangle|\psi\rangle + \sin\frac{\beta}{2}|1\rangle|\psi^\perp\rangle\right)\left(\cos\frac{\beta}{2}\langle 0|\langle\psi| + \sin\frac{\beta}{2}\langle 1|\langle\psi^\perp|\right)\right] =\\ \cos^2\frac{\beta}{2}|\psi\rangle\langle\psi| + \sin^2\frac{\beta}{2} |\psi^\perp\rangle\langle\psi^\perp| = \rho.
$$
In summary, the circuit is:

Prepare a data and auxiliary qubits in $|00\rangle$ state.
Apply $R_Y(\beta)$ to the auxiliary qubit.
Apply CNOT with the auxiliary qubit as control and data qubit as target.
Apply $R_Y(\theta)$ to the data qubit.
Apply $R_Z(\phi)$ to the data qubit.
Discard the auxiliary qubit.

Alternatively, we can measure the auxiliary qubit after $R_Y(\beta)$ and replace CNOT with a classically controlled $X$ gate. We discard measurement result after using it to control the $X$ gate.
Comment: Thank you @Adam Zalcman!


Emails Not Being Sent By Journey Builder Notification

Question: Is there a way for the admin to be notified when a contact is not sent an email through journey builder? The contact is not sent the email because of some interaction within the journey but for some reason (maybe error) MC doesn't send the email.
Answer: One way would be to setup a send log for these emails.
You could then create a verification activity in automation studio to send an alert email when this send log (data extension) has a certain number of records.
You could create a SQL activity beforehand to copy only certain types of records from the send log to a different data extension that you then run the verification activity on as well if you wanted to be more specific.


Why isn't commons-lang in the java Standard API?

Question: It seems like every java project I join or start on always has commons-lang as a dependency - and for good reason.  commons-lang has tons of classes and utility methods that are pretty standard fair with the most standard APIs in other languages.  Why hasn't Sun/Oracle/JCP adopted some of the things in commons-lang in to the standard api?
Comment: I'm pretty sure *some* of commons-lang have made it to Java 7.
Comment: I see it uses no generics, what about using Guava instead?
Comment: actually, part of the intent of the guava project was to be included in jdk 7.  dunno if that will be reality or not.
Comment: "it seems like every java project I join or start on always has commons", that's a company policy; I'd say I have not seen it included from get-go
Comment: @bestsss - I'm a contract developer and work for 2-3 companies a year and on a handful of OSS projects.  It's not a "company policy" thing at all.
Answer: As pointed out already, some features in the commons API have made it into Java, often implemented (IMHO) better than they were originally in the commons library. Enums is the classic example.
In terms of why they don't adopt more of commons-lang, well with some classes there's the element of confusion. Take StrBuilder for example, it's more powerful than the Java StringBuilder and it's extensible. But I'm not sure I'd be for adding such a class into the Java core API, StringBuilder/StringBuffer are perfectly good enough for most purposes and having another one in there would really just become a bit confusing. They couldn't really alter StringBuilder in a way that would accommodate all of the changes either because that could break existing code. Even if they did add one, what about when someone else came along with another more powerful version? StrBuilder2? Before long everything's a big mess (some argue that the core API is already, let alone with such additions.)
And as always with these things, the big point is what should be included from commons-lang. Some people would probably want to see the MutableXXX classes added, others the XXXUtils classes, others the time package... there isn't really a common consensus.
The other big thing is that the Java developers have to be a lot more careful what goes in the core Java API than the Apache developers do for commons-lang. If a crappy design in commons-lang is superseded in a future release, the old one can be deprecated and subsequently removed (indeed this seems to be what happens.) In the core Java API it needs to stay for backwards compatibility reasons, just causing more clutter.
For what it's worth though I do think more of the functionality in commons-lang should probably be included. I can just see the reasons, at least in part, why it's not.
Answer: Historically Apache Commons implemented some of the features that later were introduced in Java 5, such as enums and annotations. Their implementation was sufficiently different to make integration difficult.


Prevent existing CSS from styling injected HTML/CSS

Question: I'm working on a project which injects JS+CSS+HTML over web pages which I do not have control over.
I am concerned about the host page styling my injected code -- I want my injected code to only obey my styling, and not theirs.
At the moment the only method to do this I can think of involves explicitly specifying every possible tag for the container
's class (using pre-defined, known browser defaults) and relying on inheritance for those rules to propagate down to the rest of my injected HTML. This CSS would need to appear at the bottom of the page's  tag.
I don't think that's the best solution, though, and I don't look forward to implementing it. Surely there are better ways.
Comment: Try to implement Shadowing on that div.
Answer: Others have suggested very good ways to prevent your CSS from affecting the page's, as well as making sure that your CSS takes precedence, but you seem most concerned with the page's CSS affecting you - that is, adding a funky, unexpected style (like making all divs have a pink background).
The only way I can think for you to prevent their styling from affecting your injected code would be for you to sandbox what you've injected, like in an iframe.  Otherwise there's simply too many things that you'd have to define - you'd have to define every single style (padding, border, margin, background...  the list goes on and on) on the "*" selector (or better yet, "#yourid *", so you just override your own content), just so that you can guarantee absolute control over your CSS.
Edit: I realize that the latter solution wouldn't necessarily be too painful, if you're using the omni-selector to reset everything to a baseline:
#myid * {
    somestyle1: default;
    somestyle2: default;
    ...
}

I've found someone who has written up such a solution.  If you scroll down far enough on the page, you'll see it (from SuzyUK).  It doesn't look complete, but is a good start for sure.
(I, too, would be interested to know if there's a good way to prevent this.  I've written Greasemonkey scripts before that injects code onto the page, and have had to write CSS to override the page's CSS, but in those cases I knew who my target was and could tailor my CSS directly towards the page.)
Comment: Here's a more recent element-targeting CSS reset: https://github.com/premasagar/cleanslate
Comment: Have you thought of shadowing that particular div.
Answer: Wrap your injected HTML with a specifically-classed
, such as

Then in your CSS, prefix all rules with .my-super-specialized-unique-wrapper and use !important on every rule. That will instruct the client browser to treat your rule as supreme for any elements which match, regardless of any other styles that might target them - even if other rules outside your control are more-specific.
Comment: Thank you for your answer!

I'm already using super-specific class names for everything, so that's done and done. :-)

I do have a few questions though:
- Will CSS rules by specifying element names (e.g. `div layer table {}`, etc) override !important
- Do I need to specify !important for every rule?
Comment: !important overrides *everything* else, no matter when, where or how it is specified. You need to specify it for each style on each rule where you have concern that style may be overridden by another one outside your control.
Comment: Of course, there's potentially an added concern if the stylesheets you don't control also employ !important. Then I believe it is a matter of which !important is declared last.
Comment: @Rex, I believe that it would go to standard specificity rules if there are two !important rules competing. In any case, you'd still need a CSS reset on your wrapper.
Answer: You'll just have to be very specific with your CSS selectors. That is, much more specific than the host page's CSS rules. You might also want to add a kind of global CSS reset modified to only reset your HTML. By that, I mean something which resets all colours, backgrounds, fonts, padding, etc, back to a single standard. From there you can build up your own styles.
Comment: CSS reset is for standardizing across browsers, not across CSS stylesheets.
Comment: No, your standard CSS reset will not, unless your CSS reset does *every* style.  Standard CSS resets are just to correct browser differences, such as margin and padding defaults.
Comment: +1 for the Eric Meyer reset and not the dreaded * { padding: 0; margin: 0 }
Comment: yes, but a CSS reset (with more specificity than the host CSS) will override previously set rules (removing funky pink backgrounds and the like)
Comment: Pink backgrounds are a CSS stylist's friend!
Answer: Why not injecting html elements with inline formatting like this:

This to be injected

inline styling takes precedence over any other rule, and you're already creating the markup in order to insert it.
Other solution would be to use very specific DOM id's on your elements and then styling them on your added CSS
Comment: this wouldn't help if the host CSS changes the styles in other ways, eg: p { font-weight: bold } ... you'd end up with red and bold paragraphs.
Comment: True. I assumed he inlined all the style attributes he wants, not only the color. It was just an example.
Answer: If you're using a Mozilla browser you can actually (if illegally) add visible DOM content to the  element outside the  element.  This will avoid any styles that match on body and are inherited by your content.  It may be possible that some styles match on html, which would defeat this technique, but I've found it useful.
eg. using jquery: $('html').append('
 blah blah blah
');
Using a popular library is itself a challenge when you don't want your instance of the library to interfere with the uses of the library defined by the pages you're modifying.  Greasemonkey's '@require' didn't work for me.  I found it necessary (but possible!) to save any existing values of the two or three global names assigned by the jquery script, insert my instance of the library into the DOM, wait for it to be loaded (had to use a timer, that's annoying but I couldn't see a way around it), cache the values assigned to the globals within my own namespace for my own use, and restore the saved ones.
Answer: I'm not sure how should it be used, of the browser support for this, but it is one of the main causes to use http://www.w3.org/TR/shadow-dom/
The idea is that you could insert a web-component, that can be fully styled and have specific events that only affect the shadow-DOM (so your module will not affect the rest of the page).
Answer: Te best is to use iframe instead of injection html string.


can PostgreSQL function talk to SQL Server 2000 as a linked server

Question: Situation: gradually migrating a boatload of legacy SQL Server apps to PostgreSQL.
Question:  can a PostgreSQL function execute a query against SQL Server 2000 database? Anything comparable to OpenQuery  in PostgreSQL? Or like Oracle's Heterogeneous Services?
Answer: You can you DBLink between PostgreSQL instances.  There is a project out there for doing this to MSSQL call dblink-tds.  I have never used it, so I can't say how well it works. And it looks pretty old, so I'm suspicious it may no longer be supported.
But, remember with PostgreSQL you get your choice of languages to use.  if you need to access data in other non-postgresql stores, you can use one of the "un-managed" languages.  For example, plpythonu or you can always write your functions in C and access any information you need/want.


Are bells the only instrument whose second harmonic forms a minor interval with its fundamental?

Question: I heard (from a Paccard church bells rep) that bells are the only instrument whose second harmonic forms a minor interval with its fundamental. Is this true?
Comment: It's not a _harmonic_ if it doesn't follow harmonic series. Appropriate names in this case are _partials_ and _overtones_.
Comment: The pitch we perceive on a "minor third" bell is the 5th partial, aka 4th harmonic, with the secondary tone being the 3rd partial.  The reason we don't perceive the fundamental as the bell's pitch is that when it is struck with a hard object at the right place, the fundamental tone is inaudibly weak, just as the fundamental is relatively weak in violins, oboes, and other bright-sounding instruments.

Another instrument whose apparent pitch is different from its fundamental is the Timpani (well, timpano since it's singular), sounding an octave above the fundamental.
Answer: In short the question boils down to: are there any other instruments able to produce a spectrum which does not follow the harmonic series, neglecting inharmonicity.
Well, any instrument whose oscillator is more than unidimensional (most "standard" instruments fall in that 1D category: the air column is 1D in winds, strings are 1D...) is in theory able to produce overtones that do not follow the harmonic series. As you stated, bells can (they are basically a surface as the oscillator (not the resonator), hence 2D) but so can every instrument with a membrane (drums, tabla, steel drum...). Now, it is true that the envelopes of these are generally very different from bells, but even if none is tuned like that now, it is theoretically possible for all this family of instruments.
Comment: Even some "unidimensional" objects produce non-harmonic overtones.  For example, anything involving the vibration of a "stiff" object (e.g., xylophone, glockenspiel, tubular bells, kalimba) produce harmonics that are not in a strict harmonic series.
Comment: The most important vibrational modes are along the length of the bar/tube/etc;  there's minimal flexing or twisting in these cases.  Mathematically, this means that the vibrations are effectively 1D, since the transverse dimensions don't come into play.  It's similar to how an air column is really a 3D volume of air, but in the modes that are important for instruments, the pressure only varies along the length of the column and not across the length of the tube.
Comment: @MichaelSeifert Yes, but the approximation of unidimensionality does not hold as well as for a string or a normal air column. A thin plate will have significant flexing and torsion, depending how are the boundaries conditions. Thin cylinders can also exhibits modes along their length and in their sections, none of them negligible
Comment: @MichaelSeifert I tend to agree with Tom; for instance, while keyboard percussion instruments can be simplified as unidimensional, their bars are still quite bidimensional (and, in fact, three dimensional), and the second dimension can affect a lot: given a large enough bar, and having 4 parallel points of suspension (where the strings normally are), their horizontal position (the distance from the vertical axis) can change how the body can actually vibrate just as much as the vertical distance does.
Comment: @MichaelSeifert But if I'm not mistaken, all of your examples are 2D... Tubular bells are cylinder (not an air column) and the others are surfaces with length and width. All of this is of course forgetting about inharmonicity.
Comment: I don't know enough about these aspects, but let's remember that "unidimensional" objects can be *pitch-bent* to some extent (I was actually considering asking about this for some time, as I'm quite curious about it). https://www.youtube.com/watch?v=8MRgL2cYGTc
Answer: There are "minor third bells" (e.g., church bells) and "major third bells", thus instruments can be tuned to have these different properties.
The correct terminology in the context of bells is "prime" and "tierce" (not "fundamental" and "second harmonic"; as user1079505 notes, "It's not a harmonic if it doesn't follow harmonic series.").
Table 6.2 of Sethares, Tuning, Timbre, Spectrum, Scale (p. 117) gives the partials:

Name of Partial
Ideal Minor Third Bell
Measured Bell
Ideal Major Third Bell

hum
0.5
0.5
0.5

prime
1.0
1.0
1.0

tierce
1.2
1.19
1.25

quint
1.5
1.56
1.5

nominal
2.0
2.0
2.0

deciem
2.5
2.51
2.5

undeciem
2.61
2.66
2.95

duodeciem
3.0
3.01
3.25

upper octave
4.0
4.1
4.0

Ibid. p. 116:

Traditional church bells tuned this way are called "minor third" bells because of the interval 1.2, which is exactly the just minor third 6/5. Bell makers have recently figured out how to shape a bell in which the tierce becomes 1.25, which is the just major third 5/4. These are called "major third" bells.

For example, this bell is a very good minor third bell:

Name of Partial
Ideal Minor Third Bell Ratio
Measured
Measured Ratio

hum
0.5
144 Hz (Re3) = -41,0 dB
0.51

prime
1.0
284 Hz (Do♯4) = -37,4 dB
1.0

tierce
1.2
343 Hz (Fa4) = -43,2 dB
1.21

quint
1.5
431 Hz (La4) = -55,7 dB
1.52

nominal
2.0
576 Hz (Re5) = -39,1 dB
2.03

deciem
2.5
717 Hz (Fa5) = -50,1 dB
2.52

undeciem
2.61
744 Hz (Fa♯5) = -53,5 dB
2.62

duodeciem
3.0
858 Hz (La5) = -40,8 dB
3.02

upper octave
4.0
1181 Hz (Re6) = -45,9 dB
4.16
Comment: This does not really answer the question "Are bells the only instruments..."
Comment: @Tom It does make clear that bells can be tuned _not_ to be minor third bells. Analogously, other instruments could be tuned to have different partials.
Comment: This analogy does not quite hold... It is not because *some* can be tuned not to be minor third that other instrument can. And the question was: Are bells the only instrument that [...], Which you answer by: some bells don't. But that does not tell about the "only instrument" at all. Maybe I'm nitpicking, I like your answer but I just feel it is not really connected..
Answer: The second lowest overtone of a theoretical drumhead is 2.136x the fundamental mode (+1314 cents) (here, here) which is within 3 cents of a just minor ninth.
Also, does a synthesizer count?  It feels like cheating, but it is an instrument, and it can be made to produce any overtones.
Comment: Yes, a synth doesn't count, since as you say it just calculates the vibrational pattern of the sum of specified input frequencies.


What are the performance consequences of encryption in SQL Server 2008?

Question: If you had a table that had 100,000,000 email addresses (example) and you want to store them securely but you don't want to take a huge hit with performance when you retrieve them, how would you go about storing them?
Comment: why don't you test it and see?
Comment: 100,000,000 email addresses would make for a great spam campaign - I'd store them in /dev/null. Perfect obscurity...
Answer: Encryption algorithms are designed to be fast. If you have decided that encrypting your data is important (and personal information such as email address is important as @Marc B pointed out) then the question becomes "which algorithm has the right performance for my use case?"
I'd suggest you look at how much throughput you are expecting and test it. Use an industry standard algorithm and see if it meets your needs. Whatever you do, don't roll your own encryption. Crypto is hard to get right so trust the experts.
I'd suggest you start with AES/CBC/PKCS5. Store the ciphertext as a blob in the database. Key storage is always tricky and has been discussed on StackOverflow a fair bit so with any luck you can get advice on that aspect fairly easily. If you get sufficient throughput with that algorithm then you're done. If not, look around for a faster algorithm. I recommend http://bouncycastle.org as a good crypto library. It has a bunch of algorithms implemented so you can experiment and find one that meets your needs.
Did I mention that you shouldn't roll your own encryption? Good.


Dog refuses to eat unless fed by hand

Question: My dog is a 3 year old Pomeranian. He is very happy, active, and loves to be around other people. He used to eat only when people were around him so I used to accompany him during his eating times, which are during the morning and the night. Nevertheless, I have been having a problem regarding his eating habits.
A few months ago, an aunt stayed with us and hanged around the home most of the day. She loves animals, so my aunt spent a lot of time with my dog. She pet him, took him out, and started feeding him by putting the food on her hand and then he would eat it from her hand. She would pretty much feed him like if he was a little kid, which I thought was ridiculous. I talked to her about the issue, but she disregarded my conversation and did it behind my back. My aunt left a week ago, but now the problem is that my dog refused to eat unless I do the exact same thing. I am worried because I do not like to see him not eating for one or two days, but at the same time I don't like having him eat from my hand. How can I make my dog forget this habit of only eating from someone's hand?
I was thinking I would just stop doing it and he will eventually get really hungry and be forced to eat. However, I am worried he will just stop eating completely. What is the best approach to this issue?
Comment: My dog once did something similar.  I found that taking some food out of his bowl and placing on the ground next to the bowl would (for some reason) attract him to the food on the ground which he ate.  After he got the taste of food in his mouth, and saw that there was more food readily available in his bowl, he began to eat the rest.
Comment: Possible duplicate of [Why won't my dog eat on her own?](https://pets.stackexchange.com/questions/219/why-wont-my-dog-eat-on-her-own)
Comment: I have a Pomeranian dog 1half years old got him from a lady who miss treated him and hand fed him spoiled him etc now I'm struggling with feeding he doesn't eat from the bowl and when he does it's only just once. I put his food in a ceramic bowl but he doesn't eat from that and wants for me to feed him to hand he ha very picky and now it's getting too much can anyone help me plz
Answer: A stubborn dog won't stop eating completely, he will eventually eat. Place the food in his bowl or on a plate and wait, once you see him eat out of his dish reward with treats and praise.
Feel free to add something really yummy on top, something he goes bananas for to break his will power and go for the bowl :).
Answer: Maybe he got used to being fed by hand and expects it now. Eventually a hungry dog will still eat, 20 mins isn't long for the dog to not want to eat, just leave the bowl and see if he eats at all throughout the day. Otherwise if not, what I'd recommend would be to gradually reintroduce the dog to eating out of the bowl. Feed him out of your hand right on top of the bowl, little by little or through multiple sessions, move your hand closer to the bowl of food until it's basically eating out the the bowl without your help, if that makes sense. Good luck!
Answer: I had the same issue with my guy. My aunt started hand feeding also, to get him to eat. Turned out he didn't like the sound of his tags clinging the bowl. I switched to paper plates and it solved the problem. If u have noticed ur your dog being interested when u empty the dishwasher, it may me sensitive ears keeping him away from bowl eating. I also got him a new tag that weaves onto his collar, but he still won't eat out of his metal bowl. Hope this helps frustrated fur parents
Answer: It sounds like he equates the hand feeding with affection/attention. Try spending time with him playing and or going for a walk before his normal feeding time. Praise him often. Then at feeding time, place his bowl down and crouch down beside him as you put him at his bowl. Talk to him; praise him. I think he will begin to eat on his own.
Comment: I crouch with him for at least 20min, yet he just turns his head and refuses to eat
Comment: How about the playing with him, walk before meal, extra attention, etc.?
Answer: Ny silky terrier stopped eating so vet took test and found his blood test chemistry showed beginning of a kidney problem. He lost his appetite because kidney seems to affect the smell and taste.  I'm not saying your furpets have such a problem just mentioning it for my petbaby.  Sometime they just don't like the smell of certain bowls or pick up on what it's on or just don't like the smell anymore .... it could be anything.  But a clean had is much better than a bowl anyday from whoever it is that loves them.  (:(:  P.S.  He's okay now but sometime wants the hand....!
Answer: I had to feed my traumatized puppy the same way. I allowed it until I was certain he was bonded to me. And then I would give him a piece of food from my hand, but close to his dish. I'd offer him the next piece of food even closer to his bowl. For the third piece, I'd hold my finger in his bowl. When his mouth was in his bowl and taking food on his own, I could remove my hand. It did take a little longer for him to stop following me if I walked away to let him eat. These things take a lot of patience. Remember that animals do not think like humans -- but humans have the ability to experiment with different ways to train and "reason" with animals. If one way doesn't work, try something else. Be firm, but loving and reassuring. Your dog won't die if he goes without a meal or two (be sure he's getting water!). But if he continues refusing food, you should speak with your vet and get professional advice. Good luck.
Answer: Make the dog sit in front of his food until he eats. If he tries to move away put them back. My dog is spoiled because i make her breakfast lunch and dinner...so sometimes shes picky and or wants negative attention. Usually in 15 min she will eat.  Lucy..sitting in front of food.
Answer: It sounds like the situation is more that your dog doesn't like to eat under certain circumstances, and that he wants to eat when everything is calm, quiet, and still.
When it is time to feed him, recreate a calm, quiet, and still situation. Perhaps play some games on your phone with the volume low. Try doing this where he can see you and eat at the same time.
You can also see if the hand-feeding is tied to other preferences around his eating circumstances, such as the cleanliness of the bowl, preferring a different material of bowl, or preferring a raised bowl rather than the bowl being on the floor. Many pet stores will let you try their products with your dog in-store, but if you aren't sure, you can ask an employee if it would be okay.
The biggest concern in hand-feeding situations is that it can be covering up a health alert that the dog doesn't want to eat his food at all. But this doesn't sound like your situation.
We have a dog that is both picky and sensitive, and we had to investigate all of their preferences in order to get the most consistent eating as possible. Your situation is uncommon, but not unheard of, and the take-away is that it isn't the hand-feeding but something around it that your dog is preferring more.

Dog refuses to eat unless fed by hand


what is the correct way to pronounce "disease" , /s/ or /z/ sound?

Question: Merriam Webster dictionary's phonetic transcription is /dɪ-'zi:z/. But in this movie trailer: The Thinning 2016, min 0:13 'What causes disease', it sounds like /dɪ-'zi:s/. I believe i hear the hiss sound at the end. So which one is correct? which way should i go with?
Thanks.
Comment: You can rely on the pronunciation presented by any dictionary, e.g. [**Collins**](http://www.collinsdictionary.com/dictionary/english/disease). /dɪˈziːz/ is standard in both BrE and NAmE. The alveolar hissing sibilant is not heard, and even in the trailer you link to, it's not there to my ear.
Comment: Are you talking about the *second* "s"? I'm assuming so but it might help to clarify.
Comment: Note that the transcription in the dictionary is really a *phonemic* transcription, not a *phonetic* transcription.  You're asking about a *phonetic* detail, so the dictionary can't help you here.
Comment: @Catija Yes, i'm talking about the _second_ "s" :)
Answer: Listening
The phoneme here is /z/, just as you'd expect based on the transcription available in a dictionary.  That is to say, native speakers of English will definitely hear this sound as /z/.
However, you're quite right that you're hearing an [s] sound!  The /z/ sound here has undergone a phonetic process known as devoicing, something native speakers generally don't notice (as you can see from the comments section on your question).  With devoicing, the /z/ phoneme in this word is actually pronounced as [s].
In fact, it takes special training to be able to hear this, as this distinction is non-phonemic in English, and native speakers spend their whole lives training to ignore non-phonemic distinctions.  You can hear it because you're a non-native speaker, so you haven't trained your whole life to ignore it.
I am a native speaker, and I hear a /z/ in this recording as well.  And yet, if I isolate just the /z/ sound, removing all of the other sounds before and after it, I hear an /s/ instead!  So yes, most of the /z/ sound has been devoiced in this example, and your ears are working properly.  It's simply a matter of how our brains interpret the sounds we hear being different.
In this case, /z/ is devoiced because it's in utterance-final position.  For a full explanation of when this sort of devoicing occurs, please read Araucaria's post on English Language & Usage.
Speaking
As Araucaria explains in his answer, you do not need to try to devoice the /z/ in this sound when you say it yourself.  Native speakers do it, but they generally can't hear it, so there's no reason to try to do it yourself.
When you pronounce this word, pronounce it as the dictionary suggests, with a [z] sound.
Comment: Skeptics can visit [**this link,**](http://big-no.com/disease) where they will find a clip of the word _"disease"_ taken from the trailer; I have inserted .3 seconds of silence between the phonemes. The unvoiced sibilant is clearly heard at the end.
Comment: Nice post (I voted earlier this morning). You might want to add that in this case it is because the /z/ comes at the end that is is devoiced (the middle /z/ is, of course, likely to be fully voiced all the way through) :-)
Comment: @snailplane your post is helpful, yes, indeed. only 1 thing i dont really understand. "...this disctinction is non-phonemic in english, and native speakers spend their whole lives training to ignore non-phonemic distinctions...". What does **non-phonemic** mean? Do u mean this disctinction( either /s/ or /z/) doesn't change the meaning of the word? Thanks
Comment: @glacier1500 "Phonemes" are the sounds as native speakers hear them.  English speakers use two different /p/ sounds in *pin* and *spin*, but they hear them as the same sound.  Because they hear them as the same sound, they will never use that distinction to tell the difference between two words.  Likewise, in this case, native speakers won't be able to hear that the final /z/ is pronounced as [s], so you don't need to pronounce it that way yourself.
Comment: @P.E.Dant's link is broken.
Comment: NOTE: link restored...
Answer: It depends on the accent of the speaker. The second syllable (disEAse) is the one which is stressed, so an "s" and a "z" sound should be hard to distinguish from each other.
The "s" in (dis)ease is pronounced similarly to the "s" in "license" or "exercise"
Comment: Woah! The final consonants in _license_ and _exercise_ are **not** pronounced similarly. You can't mean to say that a voiced and unvoiced sibiliant sound the same to you. In /dɪ-'zi:z/ , the /z/ is voiced. In /ˈɛksəˌsaɪz/, likewise, the the /z/ is voiced. In /ˈlaɪsəns/, the /s/ is **not** voiced.
Comment: Hmm... are you saying as a native speaker, you would have a hard time distinguishing "seas" from "cease"? To me, it doesn't seem much more difficult than distinguishing "strive" from "strife". And do you really pronounce "ease" to rhyme with "cease," as your last sentence implies?
Comment: For most (I'd think, all) native speakers, "license" has the sound /s/, and "exercise" has the sound /z/ (like at the end of the word "crystallize").
Comment: Got here via a double-hop from a top meta post. Just chiming in to say that I pronounce license to end in /z/, or /n(d)z/ if you must. And now I'm horrified to find no justification for my pronunciation after a quick search. Might be a regional thing. Native AmE speaker, spent childhood in Tennessee/Virginia, adulthood in Texas => my accent has a lot of laziness in it (e.g. vowels like *pin* = *pen*, consonants like *wasn't* => somewhere between *wadn* and *wa'n* with no final /t/).


Map state in XNA on WP8

Question: I am developing an RPG for Windows Phone 8 using XNA. I have a map screen and a fight screen. I want to use XNA for both to utilize the graphics helpers and because XNA is awesome. My question is, how do I save the map state between the two screens? That is , how do I save the location of the PC and the enemies when I travel back and forth between the two screens?
Comment: You either need to be more specific to your problem or you need to read some beginner level programming books. Likely both.
Comment: @indeed005 I think it was pretty clear. :)
Answer: If you're using some kind of State Management this will just happen automatically. You'd have two states or screens in the case of the Microsoft XNA sample.
GameplayScreen
We can call this your gameplay screen state which would compromise of a few things but for your case you could just have the map on this screen and other things like input for moving around the map and logic for updating entities on this map. You wouldn't include things that aren't related to your "overworld" or "map" display. Things like a mini-map may go here but the decision is yours on how you separate your logic. Ideally, a menu would be another state but that's another discussion. However, what you should take away from this is no combat takes place inside of this state.
FightScreen
Now, when you need to transit to a battle switch the ActiveScreen but don't dispose of the underlying screen. Your StateManager should have a mechanism for disabling sending input to screens that are not active and not drawing them (optional; maybe you can enable drawing if you need overlay screens). However, the point is your state is preserved.
See this stack:

Now, when the fight is over you would simply pop the FightScreen off the stack and your GameplayScreen would automatically resume!
If you have any other questions, comment and I advise you also check out the RPG Sample for more tips and a working sample that deploys this strategy.
Comment: That is exactly what was looking for. Obviously, I am new to the XNA flow. I am used to the WP flow which involves page navigation. It totally makes sense to just draw a different screen but stay on the same 'page.' Thanks!
Comment: No problem; don't be afraid to ask questions after using the search function.

Map state in XNA on WP8


How can I modify a backup?

Question: I'm backing up my mac from a Hard Drive that someone gave to me, but I don't have enough space on my Mac. How I can delete files that I don't need to be backed up (when I try to delete it says The operation can't be completed because backup items can't be modified) from the HDD so backup wont be corrupted and I can backup my Mac?
Answer: You cannot delete files from a Time Machine backup specifically, but you can exclude things from the backup...

Go to System Preferences > Time Machine
Click Options
You will be presented with a list you can add and remove folders to be excluded like this:

By removing things like Applications folders and cloud storage services like Dropbox, OneDrive and Google Drive you can save a lot of space.
If this still isn't working you need a bigger drive to backup to.

How can I modify a backup?


Where can I check Arch-Linux updates info?

Question: I want to know if is there a page where I can check if a new update has some bugs or causes problems after the installation.
Comment: https://bugs.archlinux.org/
Answer: the first place to look is the homepage:
https://www.archlinux.org/
or the news page to be more specific:
https://www.archlinux.org/news/
the "news" mostly mentions package updates which will need manual intervention. that means "update problems" that are known and expected. it only covers official packages. that means no AUR packages.
there is also a mailing list which will email you the news items:
https://lists.archlinux.org/listinfo/arch-announce

the second place to look is the forums:
https://bbs.archlinux.org/search.php?action=show_recent
or directly in the subforum aptly named "Pacman & Package Upgrade Issues":
https://bbs.archlinux.org/viewforum.php?id=44
skim the first page for any obvious update problems. if there are none then you are usually good to go. either that or you will be one of the first to be experiencing the problem. there is no 100% safety.

also the bug page:
https://bugs.archlinux.org/index/proj1?order=dateopened&sort=desc
but most people tend to post on the forums first and in bug page later, if it has been confirmed to be not a custom configuration problem.

bonus: there is a tool which "enforces good discipline" when updating.
https://github.com/brandoninvergo/pacnanny
i do not use the tool. it is also already three years since the last update.
Answer: To add one minor point to lesmana's already excellent answer:
Pacmatic (GitHub), another wrapper around pacman, force feeds you the dev announcements and also specific news items related to your installed packages.
I haven't used it myself; I just ran across it in the Pacnanny README and feel it deserves a mention on its own.


Sync leads with Salesforce

Question: I am working on a web application where we are syncing our system generated leads with SalesForce.
When a user comes to leads screen in our web application we show them a button to log into SalesForce (SF). We are using OAuth and Rest Apis to ask users to login to SF. When the user clicks the button (on my leads page) user is directed to SF to get authenticated. SF in return sends us a token which we use to communicate/sync our data with SF. Everything is working perfectly fine, however there is one problem.
I dont want the users to log in everytime they have to sync data. Is there a way for users to log in to SF from my web application only once and I can remember the users settings (just like 4 square I only provided my FB and twitter account information only once and now 4square remembers me).
I did try a solution where I asked for users SF user id, password and his secruty token and I saved that in my database locally and using web services provided my SF logged in automatically and able to sync data seeminglessly.
I am not sure if storing users' SF account details is the right things to do (industry standard) and I know that its going to be little tricky for users to get hold of their security token.
What is the industry standard of seeminglessly pulling and pushing data to and from SF without asking users to get authenticate.
Thanks
Answer: Use OAuth flow to obtain a refresh token. You can then store this refresh token without compromising the user's credentials. This would be the recommended approach. See oauth refresh token for info.

Sync leads with Salesforce


When should a moderator close questions?

Question: I have seen on this site that a single moderator(@goldpseudo) controls the whole site without any concern about establishing consensus and engaging the community in closing questions , ideally the community should vote to close a question , most of my own closed question were deleted and closed by this single moderator without establishing any consensus atleast from other mods. Since this is a beta site the moderator's major role is community building but taking away the responsibilities of the community and misusing the  community features like "voting to close" makes the community feel that their votes are of little value.
Answer: We have the power to unilaterally close posts that need to be closed because we can't always wait for the community to do so themselves, especially with a community as undeveloped as this one.
Of the 2200-odd users on this site, barely fifty of them — four of which are moderators — are capable of casting even a single close vote.  Even if there was a clear unanimous agreement among all these users that a particular question needs to be closed, it would still require enough of them being active at the same time and looking at the same post to cast sufficient votes to do anything.
And the longer one waits for this community action that may never reach critical mass, the more likely a bad question is to just attract bad answers or otherwise detract from the quality of the site. Which will, of course, deter the actual experts we're trying to attract from actually participating in the site at all, thus preventing us from building the necessary critical mass to do the community action, and so on. It is a vicious cycle.
If we had a developed community, moderators would not need to unilaterally close posts near so often. But we are not at that point yet.
So, in short, when should a moderator close questions?  When he sees a question that needs to be closed.  Period.


Steam game transfer

Question: My previous computer has basically died. And I was wondering if I could transfer all of my steam games onto my new computer? I have re installed steam, and a bunch of my games aren't there to be redownloaded, probably because they were on a free sale.
Answer: If you want to download free games you had previously, just search for them in the store and download. Only games that you have bought(or received as gifts) will show up on your games list as uninstalled, free games will never show there but can be downloaded all the same from the store.
Examples of such games: Loadout, Alien Swarm.
Answer: I do not recall Steam ever giving out games for free in sales. (There are some games that are free, but those are free forever. You just need to re-find them on the store and redownload them.)
Most likely you downloaded the game on a Free Weekend -event. Those games do not work after the weekend, unless you buy the game.
Comment: Every few days games will be free, only for a limited time, so no to both.
Comment: @Mitchell Every few days? And they're not the free weekend games? Are you sure you're using Steam?
Comment: Those are the _Free Weekend_ events, I belive. Once the event is over, you may still have the game installed, but you can't play it untill you buy it.
Comment: @Mitchell don't think I've ever seen a game go from a commercial product to free every few days, and the free weekends don't happen that often, it would be a fairly terrible business model.
Comment: Nope, they gave away Civ V and Bad Rats etc for free before.
Comment: Not sure if that's aimed towards me, but I certainly never said that Steam has never offered commerical games for free.
Answer: You probably mean free weekend games. They are only tied to your account during the free weekend, then they get removed from your account unless you bought them. All other games are permanently tied to your account.

Steam game transfer