Flow rate of an open tap

Question: If I have an open tap such that there is a continuous stream of water falling through height $h$, is the flow rate the same at every point on $h$?
Comment: Sorry but can you provide a picture of that continuous flow because there are certain detail needed for answer
Comment: The continuous flow would just be that of a tap that water is being ejected with a velocity v vertically down I hope this is enough information.
Comment: Does this answer your question? [Why does water falling slowly from a tap bend inwards?](https://physics.stackexchange.com/questions/525904/why-does-water-falling-slowly-from-a-tap-bend-inwards) This **question** might have an answer for your question.
Answer: The average flow rate must stay the same all the way down, unless water is piling up somewhere. A possible exception is if the fall is so far that some of the water evaporates on the way down.  But all the water has to go somewhere.
If the falling water column has cross-sectional area $A$ and speed $v$, the volume flow rate is $Av$.  If the water is in free fall, it will have speed $v=\sqrt{2g(h_0-h)}$, where $h$ is the height of interest and $h_0$ is a height-like parameter that you twiddle to get the flow rate right at the tap.  The constant volume flow rate gives $A\propto 1/v$, and you can plot the radius $r\propto \sqrt A$ to get the characteristic wide-at-top trumpet shape of water falling from a slowly-running tap.
Answer: To make the situation a little simpler:
1.let us neglect the viscosity of water for a while.
2.density of water remains the same at every point.
Now, using Bernoulli's equation:

Let us compare two points in the stream at different heights but near the edge of the stream. So, the pressure at both these points will be almost equal to the atmospheric pressure. So the pressure terms on both sides of the equation will cancel out.
Now as the density of water remains constant throughout, ${\rho}_1={\rho}_2=\rho$. Now, the equation will look like:
$$\rho g h_1 + \frac 1 2\rho {v_1}^2=\rho gh_2 + \frac 1 2\rho {v_2}^2$$
So, you can clearly visualize that if $h_1\gt h_2$ then $v_1$ must be less than $v_2$ to satisfy the equation.
The rate of flow equals $\frac{dV}{dt} = A\times {v}$.
Where ${v}$ is the instantaneous velocity.
Now, according to the theory of continuity,
$${A}{v}=constant$$
So the rate of flow will remain constant since as the velocity is increasing, at the same time the area is decreasing.
Comment: Take a look at this site: https://math.meta.stackexchange.com/questions/5020/mathjax-basic-tutorial-and-quick-reference You'll get used to it soon for making math formulas! As you are thirsty for concepts...:-)
Comment: Your first assumption can't be correct, this is explained by rob. The width has to stay the same to ensure the same flow rate.
Comment: Ya I changed it...thnx
Answer: If you hold a bowl under the stream at every height, you do not expect the rate at which the bowl is being filled to change; it should be exactly the same rate as water is getting out of the tap, otherwise either extra water is being created in order to compensate or it is being vanished, which is in contrary to the conservation of water! Therefore the flow rate must be constant at any height.
Comment: That is correct, but it is not the only factor in determining the amount of flow; if you look carefully you will find that thickness of the jet has reduced where the velocity has increased. You might think that this leads to a constant flow as a result, but even though it is true that the flow is constant, I would instead prefer to say that the fact that flow is constant leads to the inverse relation between velocity and thickness.
Comment: But wouldn't the water be moving faster at the bottom of the stream as gravity has accelerated the water ? Wouldn't this suggest a greater flow rate at the bottom ?
Comment: I understand that what you have stated to be correct for a stream of water with constant velocity but a tap isn't a constant velocity stream as the water is in free fall after it leaves the tap.
Answer: As the water in the stream is accelerated by gravity the diameter of the stream gets smaller, but the liters per minute flow rate does not change.
Answer: When you say "continuous stream" I assume you mean that water is leaving the tap at a constant rate (e.g. 10 liters per minute).
As others have noted, regardless the speed of the falling water, acceleration by gravity or not etc, the flow rate in volume per time interval is constant.
If you have a hose with an open end, and you hold it loosely in your hand a wide stream of water exits the hose at low speed and hits the floor a few feet in front of you. 10 liters per minute is going all over your shoes. How do you know the water is low speed? Hold a child's windmill toy in the stream. It will turn slowly. Simplistically the water pushes the windmill vanes out of the way at a low speed
If you squeeze the end of the hose a little, reducing the size of the opening, the water speeds up as it exits the hose. A narrow stream of water is now hitting the floor a few yards away from you. Put the windmill into the stream and it whizzes round quickly
In either of these configurations, if you got a 10 liter bucket and put it in front of you, and filled it with the hose free or pinched or a mix, it would still take a minute to fill.
The flow rate in liters per minute is not changed even though the speed of the water was varied by the restriction* - let's say your hose had an opening of size X and water came out at speed Y, when you squeezed the opening down to half its original size 0.5x , the water would accelerate to twice its speed 2y, so overall the maths is unchanged - double of a half is the same as 1 of 1

The only sticking point in all this depends on what you mean by "continuous" and how you're measuring flow
At some point in the fall the friction forces on the water from its velocity etc overcome the surface tension and conspire to break the stream into droplets (Rayleigh instability). This introduces a potential quantization problem for you because instead of being a continuous stream, the water flow is now "in packets" and depending on how or where you measure the flow and how fast your measuring device is you may decide that anything between "no water" and "a lot of water" is flowing..
Suppose you have a sensor that measures the presence or absence of a water droplet and its size. In the space between droplets, no water is flowing. When a droplet is passing the sensor, some water is flowing. If water broke into droplets and there were 5 milliseconds between droplets (like there might be 2 seconds between the lead F1 car and the guy in second place) and then it took a droplet 2 milliseconds to pass your sensor, then your sensor is going to be detecting no water for 5 milliseconds and then detecting water for 2 ms.
If you said to your sensor "sample for 1 millisecond and tell me how much water flows", it's a good bet that it'll say "none" but it could say "X liters". Thing is, by taking this very tiny sample time you cant ever get a full picture cos you can't even sample the passing of a full droplet.. However, if you asked continuously for 1 ms samples and put them on a graph you'd have a square wave graph that 5/7ths of the time was at 0, and 2/7ths was at X - so you could say "the flow rate is not the same depending on what height in the column you sample at, and how long you sample for; sometimes it's 0, sometimes it's more".
If you swapped this out for "sample for 1 second intervals, continuously", then you'd end up with more or less a straight line graph. I say more or less because in any adjacent samples you could measure slightly different amounts (e.g. you might measure liters of 0.166, 0.166, 0.167, 0.166, 0.166, 0.167), but this is a side effect of the quantization of the sampling method rather than a true variation in the flow rate of the water from interval to interval

If we aren't measuring flow using some laser beam break/make/meaaure droplet size discrete sample method and just taking the simple route of timing how long it takes to fill a 10 liter bucket then it doesn't matter how high above the bucket the tap is/how fast (gravity or squeezed hose) the water is going when it hits the bucket inner; so long as none of it splashes out or got lost on the way down, it still takes the same time to fill the bucket
*let's assume that the water pressure was sufficient to accelerate the water without the restriction affecting the flow rate

Flow rate of an open tap


Creating checklist in sharepoint?

Question: Is it possible to create checklist in sharepoint 2013 which has some sort of tracking mechanism that tracks time (how  long did one take to finish the checklist)
Answer: You could create workflow which will be triggered by item modified, when item(status column) complete, calculated the total time Current Time minus Created Time.
Creating a workflow by using SharePoint Designer 2013
Comment: I am new to sharepoint and workflows. How many workflow do you think I need to create. The project I am working on is that managers would assign employees tasks in groups. Employees would then have to  go to sharepoint site, complete the checklist. Whoever finishes the checklist first would win. So how many workflows would be needed. I am confused as to how to go about this
Comment: Just one workflow, if each checklist represents a listitem in SharePoint list.
Comment: How do i go about the workflow. should I first choose if any value equals value (let says if status equals completed) then find interval between dates. I know workflow doesn't have then so how do i implement this ? can you help me write the workflow. Because i saw that sharepoint workflow doesn't have then. so i don't know how to write this. @Lee_MSFT
Comment: I also want to be able to send email to the users once the workflow is completed adding the time in the email?        @Lee_MSFT

Creating checklist in sharepoint?


Remove legacy templates from SDL 2011 SP1 before upgrade to sites 9

Question: Need to remove all legacy templates from SDL 2011 SP1 before upgrading to Sites 9 . Suggest options to perform the same and with some references .
Comment: Hello and welcome to Tridion Stack Exchange! The removal of legacy templates should be fairly straightforward (see my answer). However if this part of an upgrade project where the templates are in use, then you probably would want to upgrade first to the latest version that supports legacy templates and/or address how the organization will now handle rendering going forward.
Answer: To remove legacy templates in SDL Tridion 2011, select the templates in their originating Publication and delete them.
Consider creating a Content Porter export or a database backup of the Content Manager before proceeding.
If the templates are in use you will need to remove the references before deleting them. This may include unpublishing Pages and Component that use the templates (or replacing the templates and publishing), unlocalizing items lower in the BluePrint, and possibly removing history. Attempting to delete an item will report back either success or the references that prevent the deletion.


Regression with or without controlled variables?

Question: I wanted to see the impact of small business support programs on small business growth. I regressed their growth (represented by the number of employees) on only those 5 kinds of support programs (as regressors). and I found R squared= 0.35, adjusted R squared= -0.03, some coefficients are positive while some others are negative, and all the p-values is > the significance level (10%) (coefficients are insignificant). 1) May I conclude that the support programs have a positive but insignificant effect? 2) Should I include control variables to complete the model (so that r squared become > 0.5).
Comment: The negative adjusted R squared is concerning. This usually happens when one tries to fit too many predictors into a model that uses very few number of cases. What is your sample size? And totally how many predictors do you have in your model?
Answer: First, you will likely never "complete the model."
1) Yes--insignificant with your analysis's current level of statistical power.  No--not all positive, according to your statement that "some coefficients are positive."
2) Unclear where you are getting the ".5"; perhaps you have already tried an additional set of variables and with them increased RSQ beyond that level.  But it's not a matter of "should"; it's a question of what you want to investigate and what you want to show.  Control "shouldn't" be applied merely because you can but should be used when you want to know how, and how strongly, certain variables relate to the outcome while certain other variables are accounted for / held constant / partialled out.  It makes sense to control for other variables if you want to assess the relationship of set B* to the outcome with set A already "in place," and/or if you want to see to what degree of accuracy set B can predict the outcome beyond the accuracy obtained with set A. This is seldom as easy a decision as certain texts make it out to be, and I encourage you to read widely on control and to visit threads on this site tagged 'statistical control', 'partial correlation', and 'suppressor'.
*I say "the relationship of set B to the outcome" rather than the relationship of each member of set B.  This is because, with enough collinearity, you won't reliably be able to estimate each variable's true relationship; each coefficient will be affected by the presence of all the other covariates.  So statistical control can occur, and its related problems can apply, within a block of variables just as between different blocks.


The request failed with HTTP status 401: Unauthorized

Question: I have an ASP.NET website that uses the ReportViewer control. I'm using SQL server 2008 from reporting. The reporting services are on another machine on the local network and my asp.net web site is on my local system. This has been working fine for the same machine like when I access reports on network it works
http:\\exampledomainname\reportsserver

But when I want to access my reports from local host,
i.e http:\localhost\reports
I get the following error :
The request failed with HTTP status 401: Unauthorized.

Any other assistance would be appreciated.
Answer: Set the impersonation for you web service in your web.config. This user must have permissions on the reporting server:
<identity impersonate="true" />

Comment: Please refer these links [Link1](http://social.msdn.microsoft.com/Forums/en-US/sqlreportingservices/thread/2d216af4-6586-4619-b8aa-56f05cbd8239/)[Link2](http://forums.asp.net/t/984954.aspx/1) Same is helpfull for mine case.


What's the recommended approach for getting lists for multiple selections and displaying them in MVC?

Question: I've searched both SO and Google on this but have not found a relevant / acceptable answer.
Background:
 * Using MVC 4.5
 * I have some Generic Repo<T> that I am using over the top of EF5, which in turn are accessed by generic Service<T>
 * I have domain models and view models and I am using Automapper to map between them, this mapping happens in the Service layer
 * On top of that, I have my Controllers which again are generic as much as possible.

So, to the question; I have a couple of scenarios where I need to present a list of options to the user and they have to select one or more. The options are user specific, so my domain User has a List<Location> which is their saved locations, and when adding / modifying, an Item, they are required to select at least one Location.

I am resisting the temptation to fetch that List<Location> in my controllers because I want to keep them generic and slim, but at the same time, I'd rather not have two properties in my ItemView model, one for AvailableLocations and one for SelectedLocations, because this model is used not just for adding / modifying but for search results etc.

Options:
* Should I introduce a different model for adding / modifying an Item, e.g. ItemInput?
* Should I use some custom mapping and get Automapper to get the list of available locations?
* In which layer should I fetch these available locations?

What are people's suggestions on a neat and generic approach to this please?
Many thanks!
Comment: What is the role of your generic services (I mean, how are they *generic*)?
Comment: The service layer knows what domain model maps to what view model, so it is responsible for calling the correct repo then mapping to view models. This is all done generically, e.g. Service
Answer: I would do something like this:
    public IEnumerable<Location> GetLocations() {
        return db.GetAll();
    }

Then inside of your controller (I followed this from MVC scaffolding):
 ViewBag.Locations = new SelectList(service.GetLocations, "name", "id");

(or your own checkbox list)
and put a listing control on the HTML/View page.
The reason I believe this is the best method is because the logic all resides inside the service. If you put it in your DTO/data model you may come against this problem:
What happens if you require additional logic to pull back locations? i.e. sub locations of locations.
You change your service (or override) to reflect the new changes, and this logic would go inside of the service:
    public IEnumerable<Location> GetLocations(string parent) {
        return db.GetAll().Where(loc => loc.parentname = parent);
    }

p.s. I never use generic services, the reason I have a service is because some of the data access it provides contains logic that is not meant to sit with the generic DAL.
I could make an interface or abstract service to make my life a little easier for common operations between services but once you define say a concrete, a UserManagementSerive surely you are saying you want to manage an object that has Users, and Locations and Items each having its own specific functionality?
Comment: Thanks @Smithy; I'd rather not use ViewBag as its not type safe. Doing it this way also means manually binding the results of the selection back to my model, whereas MVC should be doing that for me automatically. There must be a neater solution, surely?
Comment: @Simon actually, if you have say User.LocationID in your User model definition and you call your say Html.DropDownList("LocationID") populated via ViewBag.LocationID = new selectlist... it will automatically do the bind for you.
Comment: I have also seen methods for binding multiple values for if Locations was an array of Location object also
Answer: I don't think there is only one possible answer to this question.
I would recommend a simple, but not-so-generic approach. I would write what's called ViewModels, i.e. model classes that are related to your specific views. Then I would get your available locations from the controller, and populate an instance of the ViewModel in your controller using the fetched locations.
Basically I would expose some services like:
IEnumerable<Location> GetAvailableLocationsForUser(string userName);

Do note I've used IEnumerable<T>, not IQueryable<T>. Because the implementation will actually request the database, as it's too much bug-prone (at least IMO) if it's the role of the controller to do so (remember the deferred execution of IQueryable<T>).
And it returns a domain instance, i.e. an entity, not a mapped model. I wouldn't personally deal with anything but domain classes in the service layer. There could be domain classes that are not entities, but compositions of entities for example. This could help making efficient requests and avoiding using lazy-loading and deferred execution in the controllers. This is helpful when the controller needs a whole object graph and not only an entity.
Then I would write Models and ViewModels like the following, in the web application assembly:
public LocationModel
{
    ...
}

public CreateItemViewModel : ItemModel
{
    public List<LocationModel> AssociatedLocations { get; set; }
    public List<LocationModel> AvailableLocations { get; set; }
    ...
}

There are basically Models (ItemModel and LocationModel), which are objects related to the web application. This means there could be some web-related things in those models, for example computed read-only properties or attributes on properties (DisplayAttribute...etc.).
I would write those models multiple times, actually, because I don't think this is something that could be generalized: for example, one view could require the use of a navigation property while another view wouldn't. So this changes the depth of the mapping process depending on the views that uses the model. And I wouldn't use AutoMapper at all (only hand-written mappers).
There are also ViewModels (CreateItemViewModel), which are objects related to a single view (for example the view that allows to create an Item in this example). The difference between Model and ViewModel is that the ViewModel is related to a single view (and named according to this view). On the other hand, Models are related to multiple views (its namespace would help to know which views. For example, xxx.Item.Models for Models related to all views in the xxx.Item directory). ViewModels are built from scratch in the controller (or in a separate mapper) based on the domain classes.

In the above example, you could build a domain classes that would return AssociatedLocations and AvailableLocations, but it would require your service layer to be aware of the web part (I mean, your service interface and domain classes would know which properties are needed for a particular view). I'm not sure those properties are actually related to a single view in your application, but if it's not the case, you could also build a domain class as a composition of entities that would return AssociatedLocations and AvailableLocations:
public ItemExtended : Item
{
    public List<Location> AssociatedLocations { get; set; }
    public List<Location> AvailableLocations { get; set; }
}

ItemExtended GetItemExtendedById(long idItem);


Native SMB/CIFS through ZFS or Samba Instead

Question: I was totally unaware of native SMB/CIFS on ZFS.  This wiki doc does not mention performance differences.  What kind of performance differences exist between the two?
Answer: In my experience the kernel mode server out performed samba with my clients. If performance is your number one concern, skip samba.  That said, there are a number of limitations to the Solaris kernel-mode SMB/CIFS server, most notably:

Only runs in the global zone.  Samba can run in multiple isolated zones and/or the global zone simultaneously.
Sharing happens at the filesystem level, not the directory level. So for new shares, zfs create pool/fs a new zfs filesystem, copy data over and share it (instead of sharing an existing directory)
No following symlinks in shares, unless they are on the same filesystem.
No child mounts. If you share a filesystem, sub filesystems are not shared. (e.g. two filesystems, pool/fs and pool/fs/subfs.  If you share pool/fs, you won't be able to access the contents of pool/fs/subfs without sharing it separately.  It'll show up as a directory via SMB, but will be inaccessible.
None of the Domain controller/AD Master, WINS Server and other niceties of Samba

Of course doesn't do cross-protocol locking (a file locked via SMB is also locked via NFS when nbmand=on is set with the in-kernel server) and doesn't do VSS integration so snapshots show up in the Windows 'Previous Versions' tab in the properties window.
If you can live with the limitations of the kernel mode server and you don't need zone-level isolation, I think it's the way to go.  If you're a heavy Linux/Samba user now and like some of it's unique features, feel free to stick with it.  Also of note, if you're running SmartOS the choice has been made for you, they make it nearly impossible to run stuff in the global zone (with good reason) so you'll have to use OmniOS, OpenIndiana or Oracle Solaris if you hate Samba.
Comment: Thanks for the tips, @notpeter.  I awarded this one because I was not really looking for a discussion about context switching and kernel versus user space.  That was interesting theoretical knowledge, but not very practical.
Comment: One point of information:  I encountered horrible performance accessing a native SMB/CIFS kernel-shared ZFS filesystem with Android devices and had to set up a separate zone just to share the filesystem via Samba to work around the performance issues.  I never did determine why the kernel-mode share was so slow on Android devices as it was just too fast and easy to set up a dedicated Samba zone.
Answer: Another issue with the native SMB server: it won't share remote filesystems mounted via NFS.  Now that may sound like a bad idea at the best of times, but it was an easy way for us to, for example, make some web development areas accessible to folks.  We didn't worry about the file locking issues because the web developers were (a) mostly using Dreamweaver, which uses its own file based check in/check out methods; (b) a fairly small close-knit group; and (c) generally responsible for areas without much overlap.  I can't think of more than a handful of times that developers overwrote each others files (and generally file locking wouldn't have helped).
So, finding out that the shiny new server wouldn't happily share these files was a bit of a surprise, especially because this point didn't seem really emphasized in the various sites discussing the new SMB server.  Ah, well, if there's one thing I've learned about Solaris it's that: "things change".  :)
And, I concur that, unless these needs are critical for your shop, the native SMB server is the way to go.  It lacks the flexibility of Samba, but it does seem to "just work" once it's set up, and it does seem to have pretty good performance.
Answer: I don't have hard numbers, but I can say that the native smb runs in kernel space. Samba runs in user space. Although running in kernel space doesn't guarantee that it'll be faster, all other things being equal kernel space code will be faster.
I do know that the configuration and management of the in kernel smb is much easier than samba. What's the size of your user base?
Comment: I have a bit of a CompSci beef with this answer. Excessive context switches can impact performance. Code running in user mode vs kernel mode doesn't inherently make a difference. A block of code running in user mode that doesn't cause a lot of context switches won't really perform much differently running in kernel mode. In the context of Samba, though, it's likely that there will be a significant number of context switches (because of its fundamental nature as an I/O daemon) so you're probably right w/ respect to Samba. It's not something that's true in all scenarios, though.
Comment: Right, like I said it's not a guarantee, but in general things in kernel space tend to have an advantage. That's not to say that the advantage can't be wasted by poor programming, or that  high quality programming in user space can't be optimized ahead of kernel code. This is the classic argument of micro vs. monolithic kernels. Micro kernels are superior in almost ever way, but monolithic kernels are almost always faster every time. I wholeheartedly agree with you in compsci theory. But there's also a practical reality, kernel code tends to be faster.


How concerned should I be about herbicides in compost horse manure?

Question: I just filled most of my raised beds with locally sourced composted horse manure. When I was looking for straw mulch I started reading a bunch of horror stories about aminopyralid contamination in hay and that it's risky to use hay/straw/horse manure because of how damaging this long lasting herbicide is for broad leaf veggies like beans squash peas etc. Now I'm feeling paranoid and started a sprouting test with the manure vs potting soil. I feel like even if the test passes, I'm going to worry about partial contamination. How worried should I be? I'm in Florida if that matters.
Answer: The Health and Safety Executive  in the UK concluded that crops grown on land affected by contaminated manure are  'safe to eat', assuming the plants actually grow in the first place. Whether you actually want to eat  them or not is another matter, but that information is contained here https://www.rhs.org.uk/advice/profile?pid=477, along with full information regarding this problem. That  link contains two embedded links which might be of interest, though obviously. it is mostly aimed at  the UK market. I don't know  whether hormone weedkillers (aminopyralid in particular) were  ever withdrawn temporarily or otherwise  where you live, so it's hard to say how safe or not your manure might be.
If it turns out the manure is contaminated after you've done your sowing test, then follow the instructions in the link to deal with it.


Any way to migrate a legacy "tokenlist" token to use Metaplex Fungible Token Metadata if the token's mint authority is disabled?

Question: Title says it all. We have a token with "Current mint authority: disabled". We would love to add Metadata and update the logo but it appears this may be impossible now that the old tokenlist.json file method is EOL.
Comment: Alternatively.... are there any kind developers with access to the old archived token-list repository that could help me update a logo image file saved there?
Answer: The answer, unfortunately, is "no". The Metaplex Token Metadata program requires a signature from the mint authority.


Can this scenario lead to a race condition?

Question: Suppose that we have a message passing system using mailboxes. When sending to a full mail box or trying to receive from an empty one, a process does not block, instead, it gets an error code back. The process responds to the error code by just trying again, over and over, until it succeeds. Does this lead to race condition?
Comment: Looping without a delay, waiting for some event to occur (such as there being a message in a mailbox), is called "busy wait". It is not a race condition, but it is still undesirable.
Answer: First at all I recommend to review what a race condition means.
If the mailbox system handles "atomicity" when receiving/retrieving emails, there is no race condition. Your app may loop forever trying to retrieve a message but it isn't a race condition.
Now, let's imagine that the mailbox system does not use any kind of locking mechanism. If at the same time, you are trying to read if a new message exists, a new message is arriving to the mailbox, you may read an uncompleted message because is still reaching.
In the best case you get the uncompleted message but usually a crash occurs because of an invalid pointer, etc.
Answer: The situation you describe wouldn't in itself lead to a race, though the actions you take in response to the error could, e.g pushing a "detected this mail box is empty" message to the empty mail box. Do that from two threads, you could easily end up with two mails.


Lift & shift migration with minimal changes

Question: In Lift and Shift migration strategy there is minimal or no change. Can someone provide an example for "minimal change".
Thanks
Answer: A minimal change is not really an objective measure and can be minimal in contrast to the efforts involved when considering the polar opposite:  a greenfield migration.
Some lift and shift scenarios power down complete 19'' racks,  move the equipment and power back on everything as it was.
Others only lift and shift servers, but those servers  move to new 19'' cabinets where there are new power distribution units and new network switches. The environment changes and rack placement of the servers can change during the move. But still no configuration changes in OS and/or application settings are necessary. The network settings don't change.
Slightly more invasive are server moves when after the move and powering on a sysadmin needs to log in to the server and make (small) OS changes.
Whether  those required  changes, especially when they concern changes in IP addresses are considered minimal or not is certainly a matter of opinion.


What is "knob and tube wiring"?

Question: I assume this is some USA wiring system, am I right?
Answer: Knob and tube wiring uses two separate copper conductors, each isolated by cotton cloth or soft rubber.  The conductors are strung tightly through the cavities of your walls and floors, and depend on being separated by air in order to avoid overheating.  When going through joists, the wires pass through porcelain tubes.  In the wall and floor cavities, they are attached intermittently by porcelain knobs.
Knob and tube wiring was commonly used in North America from the 1880s through the 1930s.
Comment: See also http://diy.stackexchange.com/questions/20/should-old-knob-and-tube-wiring-be-replaced/20279#20279
Answer: Wikipedia has a pretty good explanation with pictures.
Comment: Only seen that stuff once. Kinda scary.
Answer: Knob and tube was the standard long ago. Now it's considered verboten by many insurance companies and is often replaced when a home comes under contract (either the seller replaces it or drops the house price by a significant amount and the buyer replaces it).
Comment: As a former owner of a house with knob-and-tube in Texas, I had no trouble with the home inspection when buying the place or selling it, and no issues with insurance. Knob-and-tube is not inherently more unsafe than any other older wiring system. Safety is much more a concern with aluminum wiring. The biggest problem with any older wiring is overloading--older houses simply don't have the appropriate number and load capacity of circuits for modern use.
Comment: I had no trouble getting insurance on a knob & tube home.  Once I found a firm with K&T experience, the process of getting an inspection certificate and insurance was smooth.  See also http://diy.stackexchange.com/a/20279/5960 .  K&T is soldered and (if not hacked to death by renovation) really solid.
Comment: Some safety concerns come about when the wiring cover decays and falls off and you add insullation to a ceiling for instance - it contacts the bare wires and causes short/fire hazards.

What is "knob and tube wiring"?


How can produce an "installer" in Linux?

Question: How can I produce an installer for a set of source codes for a specific application in Linux? Also, what are the actions happening when one installs software in Linux?
Comment: Depends on what you are trying to package for what context. Console app? Graphic app? Debian? ArchLinux? Gentoo? Fedora? Redhat? All of the above?
Comment: There are several threads on the topic at Stack Overflow, for example [Creating an installer for Linux application](http://stackoverflow.com/questions/2419430) and [Best approach to writing a generic installer for a Linux application?](http://stackoverflow.com/questions/254054).
Answer: As there's more than one Linux distro, there's also more than one package management solution. I think that creating an app installer depends more on the target audience than on the target system.

If you plan to produce an installer for confirmed Linux users, then a source tarball will suffice.
If you target desktop users or non-confirmed Linux users, then produce DEB and RPM packages since those two package management tools cover the major Linux distros.

Also what is the actions happening when we install a software in Linux?

For source tarballs, nothing actually. The user is left alone to compile the source archive and figure out what are the dependencies (libraries and so on) without what the application wouldn't run.
For DEB and RPM (and other package management tools) the process of figuring out what dependencies are needed and the installation operation, is managed entirely by the package management tool(a connection to the Internet is needed to download the dependencies). The package management tool is responsible for registering the just installed app and all its dependencies in a local registry system so it wouldn't be necessary to install them once more for future needs.
WIKI
DEB: a Debian package file. apt is Debian's package management tool.
RPM: RedHat Package Manager file. The same name goes for the package management tool.
Comment: +1. Also, deb and rpm packaging builds on standard source tarballs by adding a `debian` dir and a `pkgname.spec` file respectively, so the source tarball would be the first step.
Comment: Nominally at least, RPM now stands for "RPM Package Manager", despite its origin.
Answer: Prepare a makefile and make a tarball with just the source code and let every user compile it as they seem fit, and/or build an RPM package (or a .deb or something else, RPM packages are supposed to be standard).
Answer: Some commercial software or games sometimes uses Nixstaller:

Nixstaller is an Open Source project with the goal to create user friendly and flexible installers that work on various UNIX like systems.

Using Nixstaller we can create installers that works on most modern distributions, can install app locally or in system and looks like Windows installers ;).
But the best solution is to create native packages for each distribution so it could be managed via system package manager. For more details information about this you need to write more details about what you want to accomplish.


Ubuntu 13.10 Can't shutdown

Question: I recently installed Ubuntu 13.10 on my Lenovo Thinkpad S431, but it can't shutdown. Any kind of shutdown only restarts the laptop. I've tried all sorts of things from re-installing Ubuntu to shutting down from the terminal. I've read many discussions about this issue, but I can't find a solution. Any advice would be great. Thanks!
Comment: What happens when you shutdown from terminal with a command like `sudo shutdown -h now`? Please add any command output.
Answer: I would advise you to try and shut it down without any devices plugged in the usb ports.
I have read that some devices may cause your PC/laptop to start up after a shutdown.
If that doesn't work you may want to try what this Ubuntu Forums post suggests.
Comment: Please provide *a rough summary* of what the post you're linking to contains - give us the important bits instead of just linking to them! :)

Ubuntu 13.10 Can't shutdown


Spring XD dynamic deployment manifest

Question: I have been reading the Spring XD documentation fairly heavily and can't really get to grips with two things I'd like to achieve in relation to Hadoop YARN.
Maybe they aren't supported yet or won't ever be supported - possibly because I am missing something which makes my scenarios non-sensical...

In Hadoop YARN it is possible for the ApplicationMaster to request containers to be allocated on specific hosts i.e. 'rack awareness'. This allows processing to be performed close to where the data on HDFS is stored.

Can this kind of functionality be exposed as an evaluated property in a stream Deployment Manifest?
Note that I am not talking about partitioned streams where the same containers handle the same messages for all modules in the stream.
I want to have many instances of a module in the middle of the stream deployed on a set of containers - these containers would also by holding segments of my pre-existing large static data. I want the most appropriate module instance to be selected for each invocation based on an evaluated rule which involves mapping each message being processed to an associated pre-existing large file stored on one of the containers.

Is it possible to dynamically 'scale out' the deployment of one module across more containers once the stream is deployed. For instance if one module in the stream is proving to be a bottleneck once the stream is deployed can the number of instances of that module be dynamically increased across more containers?

Thanks
Nick
Answer:
Is it possible to dynamically 'scale out' the deployment of one module across more containers once the stream is deployed. For instance if one module in the stream is proving to be a bottleneck once the stream is deployed can the number of instances of that module be dynamically increased across more containers?

Direct binding of modules would help in your case. Direct binding allows the modules of the stream to be co-located on the same container and provides dynamic deployment of those co-located modules to every container that joins the cluster.
You can find more info about this here

Spring XD dynamic deployment manifest


How do I get new missions from Martin Madrazo?

Question: I can't get new missions from Martin Madrazo. I really want to try Holed Up by him and Bust Out from Lester, but I can never get them when I call them!
Answer: There are 5 ways that I know of to take part in a job:

Randomly delivered to your phone.
Using the Quick Job feature on your phone.
Calling a contact and requesting a job.
Finding the job in the world and entering the blue circle.
Pausing, going to "Online" and beginning a job from the menus there.

To do what you're trying to do, the only thing that might help you at this point might be option 5. I don't use it all that often so I can't say whether or not the specific jobs you're looking for are listed in there, but hopefully they are.


Is it plagiarism to use the same research method for similar papers?

Question: I have to submit an original research paper for my Capstone. I was pretty excited about the topic and the method. However, I was gutted after finding a pretty similar paper which employed the same method in a later part of their paper - say, interviewing food delivery executives. They focused on the same city as me, and while their topic is aligned more to gastrogeographies during the pandemic, I feel worried that my topic is too similar.
Comment: You definitionally can't plagiarize something you weren't aware of.
Comment: A cornerstone of the scientific method involves replicating an experiment to see if you can reproduce the claimed results. This is grade school stuff. What made you possibly think that applying the same methodology would be plagiarism? Do you even know what plagiarism is?
Answer: This is unlikely. You can't plagiarize what is "common knowledge" and in many fields the general structure of the methodology is standard, well known, and common knowledge.
There can be exceptions, however, in which some methodology has unique characteristics. But if you cite such a work and use its ideas then you are protected against plagiarism.
However, you also need to be concerned about copyright infringement. You can't copy long passages from an earlier paper even with citation. It can still be an ethical violation when, strictly speaking, avoiding plagiarism.
In statistical studies, say, the methodology is pretty common. The novelty is in the questions asked and the importance of the answers. Even in math, many theorems use very similar techniques.
When in doubt, cite.
Comment: +1. Plagiarism would be if you do not reference that other paper.  Similar (or even identical) topic does not constitute plagiarism.
Answer: By definition, you cannot plagiarise what you were not aware of. A prior study with similar methodology may reduce the novelty of your work, but I doubt that's a real issue for a capstone project (it may be for a paper intended for publication).
Of course, if you copy how they describe their methodology it is plagiarism, but as long as you describe your approach and data in your own way there really should not be an issue. Reference the prior work, and ideally discuss and explain the similarities and differences, and your work will likely end up stronger than it would be if it were just a stand-alone study with no direct connection to the body of research.
Answer: Not plagarism.  This sort of thing is the foundation of proper science.  As long as you do your own work, you're fine.  It's a good thing to cite other very similar papers.  They can be inspiration for you to take a look at the topic yourself.  You could be trying to replicate what are in that other paper or disprove them.  Citing other papers is an important means of passing ideas around.  This is the essence of "standing on the shoulders of giants".


ISO to USB on Kubuntu

Question: I'm running kubuntu 15.04 and I want to make bootable usb stick from an ISO file, how can I do that?
I tried this: How do I make a bootable USB stick from an ISO image?
I also tried running UUI by wine (it didn't detect my usb stick)
Answer: Use dd.
 sudo dd if=input.iso of=/dev/sdx

where  input.iso is the input file and /dev/sdx is the USB device you're writing to. This method is fast and has never failed me. Note: that the 'x' depends on the actual device the usb mounts as.
Comment: Actually, a few years ago I had some Ubuntu ISO which I didn't boot after I wrote it with dd to the USB device. Using some GUI programm it worked but I never found out what the problem was. So just as a hint: there might be some ISO files out there which do boot after writing them with dd to the usb device.
Answer: Install unetbootin
sudo apt-get install unetbootin

plug in a USB drive
Delete all partitions on the USB drive
create a fat32 partition
mount the flash drive

open up a terminal and start unetbootin
sudo unetbootin

select disk image
choice you iso
select you flash drive
then click ok

wait for that to be done and you have your self a  bootable usb stick.
Comment: When booting from a Ubuntu 16.04 Server iso, it detected that it was created using unetbootin, and presented a warning during setup, to warn use of unetbootin is unreliable.
Comment: I have found unetbootin to be unreliable as well.
Answer: You can try Unetbootin
Binaries:
32bit
64bit
The PPA repository doesn't work (for me at least), so I don't post it.
Today I've tried it (for Kubuntu 15.10), but unsuccessfully. Please post your results afterwards.
Comment: I have found `unetbootin` to be unreliable.
Comment: Whilst this may theoretically answer the question, [it would be preferable](//meta.stackoverflow.com/q/8259) to include the essential parts of the answer here, and provide the link for reference.
Answer: Use Startup Disk Creator on Ubuntu.
It should be preinstalled in both Ubuntu and Kubuntu.

ISO to USB on Kubuntu


What are the secret achievements for Runner 2?

Question: While perusing my stats I noticed that there are several secret achievements in Runner 2.  Given the quirky off-beat nature of the game, I'm curious to know if they are something I will unlock as the game progresses, or if they are of the very obscure variety.  If they are part of the plot, please spoiler tag - and I'll find them when I get there.  If not, I don't mind finding out now so I can get started doing whatever weird thing it is.
Answer: While I don't recall there being any secret achievements for the Steam version, there are a total of 4 secret achievements for the Xbox 360, and 1 secret trophy for the PS3.
The Xbox 360 achievements are:

Multiple Personalities -- Beat 30 levels as alternate characters. Way to go!
Dancing Fool -- You got the fever and danced 100 times.
Bullseye -- Perfect+?! That's unpossible!
Marathoner -- You warned the Athenians of the oncoming Persian army!

Each of these is pretty self explanatory. Meaning, to get Bullseye, you need to Perfect+ a level, to get Marathoner, you need to run a total of 26.2 miles, etc.
The secret trophy for the PS3 is:

Dancing Fool -- Dance 100 Times

Not really sure why the PS3 version has fewer "secret" trophies, but, I don't make them! I just try and get them. Regardless, all of these are incredibly easy to earn in a single play through of the game. Just make sure you use a different character while you're dancing your way to a bullseye after 26.2 miles!
Answer: There are no "secret" achievements.  Each achievement states how to get it, and it's relatively straightforward.
For the ones you are referring to, those are considered "secret" because it requires unlocking "off the beaten path" levels (the ones that are dead ends).  You can pretty much get the majority of those achievements in the first level.
Comment: It would be cumbersome for me to screen cap from my game right now, but I promise you there are a number that are listed as "secret".  Do you mean that there is nothing special necessary to unlock these achievements, apart from completing the game?
Comment: No, you'll get them normally. I assume maybe you are referring to "unlocking a single character" ones.


Can I reference an existing row in base table from inherited one?(postgres)

Question: I'm trying postgres, version 9.2
Can I reference an existing row in base table from inherited one?
Example:
i have a "person" table and a "student" table which inherits from person.
As i understand, if i insert new student, automatically new person is added.
But i need to insert first the  person data, and then insert a reference to it and  student related data.
Answer: As i understand, if i insert new student, automatically new person is added
No. Although you can select students by querying the person table, only the student table will be populated after an insert to the student table.
The relationship you want is foreign key not inheritance. Create the person id column in the student table and make it dependent on the person id on the person table.
Comment: Thank you!In my mysql version of database schema i used foreign keys.
But this "inheritance" provided by postgres dbms is not that kind of  inheritance i expected...


Model Deforms When Trying to Animate

Question: I am trying to animate a voxel (cubic) model I made in MagicaVoxel using Blender, but when I try to move the feet, the soles of the feet badly deform. Also, when I move the hands, it slightly deforms the shoulder a little bit. This is my first time using blender, so I figured I would need some help for this fix. I want to be able to move the feet, hands, and head without having them deform.
Comment: Can you upload a .blend file to [Blend Exchange](http://blend-exchange.giantcowfilms.com)?
Answer: Tweaked three things and got it to work.

Tris to Quads
The first thing I did was Tab into Edit Mode and key Alt + J to convert Tris to Quads. This is a form of retopologizing that is highly recommended. Triangles are not recommended when modeling.
Remove Doubles
I keyed W to open the Specials menu and selected Remove Doubles. This got rid of excess duplicate vertices that were messing with your Weight Painting. Of course, this destroyed the shading, so I added an Edge Split modifier in the Properties panel > Object modifiers tab.

Parenting
After all the changes to the mesh, I redid the parenting. I selected the mesh, then selected the armature, keyed Ctrl + P, and chose Armature Deform > With Automatic Weights.

Here is the fixed .blend file:

Model Deforms When Trying to Animate


Specified key was too long creating primary key

Question: Simple question: what is wrong here?
Using utf8 (CHARSET=utf8mb4) makes the internal fields larger.
What is the maximum field size for UTF8 keys?
We need to guess?
create table repos(repo varchar (200), PRIMARY KEY (repo));
ERROR 1071 (42000): Specified key was too long; max key length is 767 bytes

How hard is for mariadb to give a better error message?
btw: The answer, by trial and error, is 191 * 4 + 4 = 767.
mariadb Ver 15.1 Distrib 10.1.47-MariaDB, for debian-linux-gnu (x86_64) using readline 5.2
Answer: 767 Limit in InnoDB Indexes lists 5 work arounds for the 767 problem.
But, these days, the preferred solution is to upgrade:
This problem exists before the limit was raised in 5.7.7 (MariaDB 10.2.2?).


Highcharts x axis custom scaling

Question: I'm looking to use highcharts to create a graph with a custom (1/K) scaled x-axis for a chemistry application. I need the tick marks to be spaced differently, but not in a logarithmic fashion. For example, let's say I want the spacing between the 40 Kelvin x-axis tick mark and the 50 Kelvin tick mark to be 100px (arbitrary value), but then I want the spacing between the 140 x-axis tick mark and the 150 tick mark to be smaller than that (to be consistent with the scaling). The question is, how do I make the spacing between two tick marks (both 10 Kelvin apart) different sizes (to be computed with a formula)?
Answer: You should be able to do what you want using the xAxis tickPositioner function (http://api.highcharts.com/highcharts#xAxis.tickPositioner).

Highcharts x axis custom scaling


Why do they crimp capacitor leads?

Question: Most manufacturers produces crimped and straight lead pairs of their capacitors which has exactly same capacitance and voltage rating. Why do they bother crimping the leads? What advantage does it make? In which cases a crimped lead capacitor should be preferred?
Comment: I'd suspect that it's easier to hand-solder them, as they will hold in place after cutting the leads.
Comment: Serves two purposes:  1) Space the cap up a bit when inserted into a PC board.  2) Provide some flex so that the cap is not overstressed while being inserted into the board and soldered.
Comment: It wall also assist with draining of the flux wash and accommodate the slight size variations of thee parts when automatically held by the insertion machine and pressed in.
Answer: It's to space the capacitor up off the board so that undue stress is not placed on the ends of the capacitor (for example, if the lead spacing in the board holes is not exactly the same as the lead spacing on that particular capacitor, or if the thermal coefficient of expansion is different from that of the PCB).
As well as your pictured film capacitors, you'll find similar kinks in ceramic disc capacitor, thermistors, MOVs and similar parts.
Here you can see it clearly called a "hold off" kink on a disc capacitor.

Some other parts- NTC (Negative Temperature Coefficient) thermistors:

The capacitors you pictured are epoxy dipped, but the early laquer dipped ones were even more susceptible to damage from too much force on the leads. This should bring back some bad memories for oldsters here:
Comment: Sometimes I hand those out on Halloween.
Comment: Somehow I think "Jellybean part" got lost in translation
Answer: Ceramic capacitors are rather brittle and so they do not like their leads getting tugged on.  Adding these crimps forces the capacitor to sit off the board with a few mm of relatively flexible lead in between.  This will isolate the capacitor from forces that it would otherwise experience during vibration, board flexing/bending, thermal expansion/contraction, etc.  By providing the crimped leads at the factory, the board house does not require a machine to add those in-house.
Comment: To be specific, a straight down tug is not so bad. The problems happen if the pcb hole spacing is slightly different from the lead spacing which causes them to be tugged outward.  It also lines them up nicely for inspection.
Comment: What does exactly happen if their leads are tugged on?
Comment: Ceramic is brittle and will crack if subjected to too much force.  Electrolytic capacitors, for example, can tolerate a bit of movement on the leads because they are held in a flexible rubber plug.  A cracked ceramic capacitor will not work as intended - it can fail short or open, or simply come far enough out of tolerance to affect operation.
Answer: As the capacitors pictured are film capacitors, using the crimp to stand them off the board will help to keep their temperature below the melting point of the film during soldering.

Why do they crimp capacitor leads?


How can enable Deep sleep mode in Rasberry PI

Question: If mains fails and my device is working in battery mode I would like to disable  Ethernet, USB, HDMI, turn off the LCD backlight etc. Is it possible to disable these modules? My device battery is discharging very quickly, and I am looking for anyway to save power. This is first time working in power management.
Comment: It might be good if you provide evidence for the fact that your "device battery is discharging very quickly".  What are the total mAh, etc?  Note that  5V power banks usually use idealized specs.
Comment: You simply can't have a running computer consuming next to no power.
Answer: As is the Raspberry Pi doesn't support a Deep Sleep mode as you describe it. Most of these modules can all be disabled, but the savings are minimal and they will all require a restart to toggle on or off.
Turning down the brightness will surely help (presuming it's powered from the RPi), but how and if you can do that will depend entirely on the screen you're using. Check its documentation for information on that.
As is, the RPi uses remarkably little power. The SOC (CPU, RAM, GPU, etc) is going to be eating the vast majority of your power. If you need your device to last longer on a battery, the best answer is to simply provided it with a bigger battery.
Answer: You can disable many of the onboard devices to reduce the power footprint as described here, here, or here. The largest power reduction (100mA) can be made by disabling the USB/LAN chip (echo '1-1' |sudo tee /sys/bus/usb/drivers/usb/unbind).
Some other settings can either be changed at runtime (such as Bluetooth and WiFi using rfkill) or boot time by configuring devicetree (e.g. Adding dtoverlay=pi3-disable-wifi and/or dtoverlay=pi3-disable-bt to /boot/cmdline.txt). With WiFi it's also possible to control the power_save mode on the device (e.g. iw wlan0 set power_save on) - though this is usually enabled.
There are some others that can only be done at boot time such disabling the LEDs (e.g. disable the activity LED add: dtparam=act_led_trigger=none dtparam=act_led_activelow=on to /boot/cmdline.txt). The HDMI port can be disabled (sudo /opt/vc/bin/tvservice -o) though it usually disabled unless a HDMI device is connected at boot time.
There are also various power management options in the Linux kernel such as the CPU frequency and voltage scaling options. The default frequency governor is set to ondemand by the raspi-config systemctl service (otherwise it defaults to powersave). On the Pi4 there are some additional configuration options to control the Dynamic Voltage and Frequency Scaling (DVFS) settings at boot time. But one needs to balance the performance and energy aspects with thermal control so the device doesn't get physically damaged.
Alternatively you can use an external device to control the Pi's state and power such as Sleepy Pi or Witty.


wp_clear_object_cache() is deprecated. What should I use instead?

Question: Today I noticed that \WP_CLI\Utils\wp_clear_object_cache() has been marked as deprecated in WP-CLI 1.5.0. The release notes don't mention anything about it. What should be used, instead? Do I still need to take care of flushing the cache myself or is it handled automatically now, like mentioned here?
Answer: The function wp_cache_flush() should help you but is not the same one.
The function runs on the global $wp_object_cache and set a new empty array, different to the WP CLI deprecated function wp_clear_object_cache for different keys of the global var.
function wp_clear_object_cache() {
    global $wpdb, $wp_object_cache;

    $wpdb->queries = [];

    if ( ! is_object( $wp_object_cache ) ) {
        return;
    }

    // The following are Memcached (Redux) plugin specific (see https://core.trac.wordpress.org/ticket/31463).
    if ( isset( $wp_object_cache->group_ops ) ) {
        $wp_object_cache->group_ops = [];
    }
    if ( isset( $wp_object_cache->stats ) ) {
        $wp_object_cache->stats = [];
    }
    if ( isset( $wp_object_cache->memcache_debug ) ) {
        $wp_object_cache->memcache_debug = [];
    }
    // Used by `WP_Object_Cache` also.
    if ( isset( $wp_object_cache->cache ) ) {
        $wp_object_cache->cache = [];
    }
}

Note: The deprecated flag should be wrong, and the maintenance team will change them in a future version. That is information after a small talk with the team.
Comment: Not necessary, because he will leave this function and remove the flag deprecated  in one of the next releases.
Comment: Thank you! the `WP_CLI\Utils\ wp_clear_object_cache` doesn't just clear the full cache, it instead only deletes certain properties. Did they decide it's not necessary? I can't find an official opinion on this anywhere...
Comment: I ask Alain (WP CLI Dev Lead) and he means, the method is okay. Maybe the deprecated flag is wrong. He will check them. The difference between these two functions is clear. see https://github.com/wp-cli/wp-cli/pull/4615/files
Comment: Thank you! Any news on this from Alain?


How to transfer render data from one object to another.?

Question: The other day I was thinking about wormholes and thought if it is possible to transfer the render view data of an object with a glass BSDF to another object, so the environment that we can see through the glass BSDF should look like that of the original object. Remember the wormhole in Interstellar, where they were able to see the other end of the wormhole through that sphere floating around.
Answer: Unfortunately, real time "portal viewports" are not supported in blender. However, one way around it is to transfer pre-rendered data into a new scene. Here's an example - see if it works for you.
Make your initial scene and put your object (sphere?) in it. Select the sphere and press Shift + S and select "Cursor to selected" to put the 3D cursor directly in the center of the object.

Then select your camera, and press Shift + S again, this time select "Selection to cursor" to put the camera where the cursor is (in the center of your object).

Now, remove your object (sphere) from the scene, leaving the camera in place. Don't just hide the object - it will still appear in the render if you hide it. Either move it or delete it.
Make sure you are using Cycles engine (this particular camera perspective only works in cycles), and in your camera settings, pick Panoramic - Equirectangular.

Now render and save your image. It should look something like this (bent).

In your other scene (other side of the wormhole), add your object (sphere) and for it's material, assign an Environment Texture (not an Image Texture), and pick the saved image you rendered. Use Reflection Texture Coordinates so the "wormhole image" will change perspective as you rotate the camera. (If you lower the roughness, the sphere will even reflect the current world environment, while still showing the "wormhole" environment inside)


Redox reaction of cycloheptatriene ligand

Question:
The reaction I really don't understand is the second one which produces the cycloheptatriene ring with a positive charge. The only thing I can think of is that the hydrogen is being ejected and behaving as a nucleophile but that's atypical of hydrogen. How does it happen?
Comment: See tropilium ion.
Comment: [Link to tropylium ion](https://en.wikipedia.org/wiki/Tropylium_cation).
Answer: Nucleophilic or hydridic hydrogen is actually commonplace in organic chemistry. Examples include:

The Cannizzaro reaction whereby a single aldehyde is reacted with base to form an alcohol and a carboxylate salt, and the variant (cross-Cannizaro reaction) whereby formaldehyde is added and it is converted to formate, the other aldehyde being reduced to the alcohol.

Various reduction reactions involving sodium borohydride and lithium aluminum hydride, most commonly to reduce various carbonyl compounds to alcohols.

In both cases the hydrogen is in an environment that enriches it electronically, in the first case by the action of the base attacking the carbonyl group and in the second case by attachment to an electropositive atom. With cycloheptatriene the carbon ring is in effect also electropositive, because the cycloheptatrienyl ring becomes aromatic with a positive charge. Compare the resulting reactivity with 3-chlorocyclopropene as a source of chloride ion or, in the opposite sense of forming an aromatic anion, the acidity of cyclopentadiene.


Can I store Dark Elixir Clan War winnings if don't have a Dark Elixir storage?

Question: I'm in a Clan War and I see a little mini dark elixir storage at the top of my Clan Castle, but I don't have an actual dark elixir storage.  Will the dark elixir stay in the Clan Castle until I can claim it?
Comment: But for some reason i only see it when i click info on my clan castle -p.s im upgrading it to lvl 2 right now
Answer: Loot won in a Clan War is automatically stored in the Clan Castle at the end of every war. This includes Dark Elixir. War loot cannot be spent until it has been collected, and if you collect the loot without a Dark Elixir Storage you will lose it.
The Dark Elixir will stay in your Clan Castle until you collect it, or until its raided. I recommend you read this page from the wiki which gives you more detailed information on Clan Castles.
The miniature gold, elixir and dark elixir storages on top of the clan castle represent where the war loot is stored after a war has ended. You can see these in the following picture of a level 2 Clan Castle:

Source
Comment: From the wiki: "The miniature Dark Elixir Storage on top of the Clan Castle will not show up until you have built a regular Dark Elixir Storage (nor will the "War Dark Elixir" amount be shown in the Info screen)."
Answer: The Dark Elixir will stay in your Clan Castle until you are raided. It will not go away, and if you win Dark Elixir in your Clan Castle the next war, the Dark Elixir will only accumulate until collected. In other words, it won't disappear or be wasted unless you are raided or try to collect it without a Dark Elixir Storage
Answer: The Clan Castle houses any reinforcement troops sent by your clanmates. Bonus loot won in Clan Wars is automatically stored in the Clan Castle at the end of every war."
Answer: Actually, if you don't have a DE storage, you can't get DE from war loot, even if you win the war. This is because there is literally nowhere for your base to store the Dark Elixir. Your Clan Castle loot after the war just shows the Gold and Elixir you won, not DE. Happened to me more than once.


How can I tell when ground beef is fully cooked?

Question: So, how do you know that the ground beef is fully cooked when you are stir frying it on a sauce pan ?
Answer: Ground beef cooks quite fast. It doesn't need more than 5 minutes (depending on the base of your pan and the amount of meat of course). Just take a piece and rip/cut it open. If it's brown inside, and not red or pink, it's fully cooked.
Comment: But, be sure not to overcook it: it also dries out pretty fast.
Comment: My husband would like to know exactly how long because he's color blind.
Answer: For the color blind people:
If you're cooking the meat in crumbled form (not burgers), after you've broken it up and let it cook for a couple of minutes, add a cup of water to the pan.
Continue cooking until the water has evaporated.  You might have some fat left in the pan if it was a fattier grind, but the moisture will both help prevent overcooking the beef, and give another indicator of when it's cooked long enough.
Comment: Has anyone tried this? Wouldn't adding water steam the beef instead of browning it? How was the resultant flavour?
Comment: I've done it lots of times.  The browning occurs during the "cook for a couple of minutes" before you add the water.  Maybe there's not as much browning as cooking without water, but there's also less overcooked rubbery bits.
Answer: The USDA explicitly warns NOT to rely on color as an indication of doneness.  Per the USDA, meat may brown before it is safe to eat and also meat may be safe to eat before it browns.
If your recipe has you cook the meat after it is browned (e.g., brown the meat, then add ingredients, then cook in an oven for 25 minutes), you're probably fine.  If you're using browned meat as-is, check that the internal temperature is 160°F using a cooking thermometer.
Comment: @thelawnet: Maybe so, but the [Food Safety FAQ](https://cooking.stackexchange.com/tags/food-safety/info), linked to from the [help/on-topic](https://cooking.stackexchange.com/help/on-topic) explicitly states that chefs should "Follow the cooking time and temperature guidelines set out by [their] local regulatory agency." That's what my answer recommends. I find it kind of broken that the top answer to this question suggests "check the color," whereas the USDA explicitly says not to do so.
Comment: It's going to be difficult to check the internal temperature of ground beef, as it is ground to small size
Answer: When you buy ground beef you see it has white spots. That is what makes it oily. You will know when it's fully cooked when it is a medium brown color it should be ready. Make sure to keep an eyes on it when it's dry add a bit of water. Then cover it.  Then you do this once more let it dry and it should be ready. MAKE SURE THERE IS NO RED OR PINK


Is there good free software for editing Canon RAW files?

Question: I've lost the install disks that came with my 500D and I was wondering if there was any better software for editing Canon RAW files. I Had a quick skim of the Canon website and couldn't find anything.
Comment: You should be able to download the software from here  http://www.canon-europe.com/Support/software/dpp/
Comment: Do you mean free merely as in price, or are you looking for open source?  It sounds like the former, and you're getting answers based on that (though some are also open source)... but just checking if that's how you mean to be asking it.
Comment: See also: http://photo.stackexchange.com/q/4880/21
Comment: Note that there are very few (if any) third-party programs which will edit Canon raw files but not other brands.
Comment: I'm not too fussed about looking at the source code, I've got my photographer hat on here not my developer hat.
Comment: Note: since this question was asked Canon has dropped the need for the physical disc to download and install their own software. You will need to provide them with your camera's serial number.
Answer: Raw Therapee is an excellent piece of software and it's free.
Answer: Short answer: RawTherapee
Almost everything uses DCRaw under the hood at least for reading in the RAW data.
The differences come with the demosaicing algorithms.
RawTherapee offers several such algorithms but the one to note is AMaZE, its the one you want.
The comparison page on RawTherapee's website doesn't contain the new AMaZE algorithm but this will show you the kind of differences you will see with different algorithms.
RawTherapee was free for a long time but now it is free and open source.  It is being actively developed in the open as I write this.
Here's someone's brief review of RT.
Comment: Linkrot alert: review of RT not working.
Answer: Darktable is a fairly new project but it looks very promising and has some great functionality already.
Comment: Unless you're on Windows... :)
Comment: It's a bit rough on the edges, but I have huge hopes for Darktable
Comment: Doesn't show RAW files in their correct color for Nikon d5300 NEF files.
Answer: UFRaw, another classic free photography app
Answer: Yes. Download a copy of Canon's Digital Photo Professional from the Canon website (at least in the US).  Canon has changed their download policy and now grants access to the full installers, rather than just updaters. You no longer have to have the original disk to download the software utilities that come in the box with the camera. You simply need the serial number of your camera.
There are, of course, also good open-source alternatives for RAW conversion, most of them based upon DCRaw.  Good open source packages to consider would include UFRaw (most typically as a plugin for the GIMP), or if you prefer an Adobe Lightroom-like interface, DarkTable, PHotivo, and RAWTherapee.
Answer: The Gimp is an excellent photo editor, but lacks support for RAW images. However, there is a plugin you can get for it that will enable it to open the files.
Comment: careful though: GIMP is 8bit. This could be impactful to your RAW image which is likely 14bit. depends what you want to do, however. Word is that next ver of GIMP will be 16bit.
Comment: @Kevin: [cinepaint](http://www.cinepaint.org/) supports 16-bit RAW images, IIRC.
Answer: Picasa is a nice simple photo editor that's free, and it will take in RAW files.
Comment: This is true, but it's *very* simple... You just have to decide for yourself if that is good.
Comment: Picasa will not work with newer Canon RAW files, the 760D/RebelT6s to name just one, will display with a pink hew.
Comment: Picasa is now discontinued (2016)
Answer: Don't forget the De-Facto raw conversion utility DCRaw.
It's very user unfriendly (read: command line only), but most available RAW converters are at least somewhat based on it, since it's open source, and largely BSD licensed.
Answer: I also recommend checking out Scarab Darkroom. It is often praised for its intuitive user interface and is also relatively fast. [Disclaimer: I'm the developer]
http://www.scarablabs.com/scarab-darkroom
Comment: Please see http://photo.stackexchange.com/faq#promotion
Comment: In this case this promotion is relevant. I will take a look and try to send you some feedback.
Answer: Sorry but another simple answer here.
Irfanview is a pretty neat and fast editor I use.  Easy to install plugins and I make sure it uses the Canon dlls for processing raw files.
In a nutshell I use it to post process my RAW files into jpegs.
I shoot CR2 for everything and then use scripts to do the following
1. Copy RAW files from card to computer
2. Convert to jpg, adjusting the quality and size to be 2048 at the longest edge *
3. Call exiftool to copy EXIF information from the CR2 file into the jpg. **
4. Go through card for anything else.  Ie copy across movies or resample any in camera jpgs into lower quality ones.
5. Run synctoy to backup images.
6. Run picasa to sync to web
7. MANUAL step.  Go through RAW files on the computer and keep the best ones, deleting the rest.

I use Picasa as a backup solution.  With a Google+ account you are allowed free storage for images upto 2048 at the longest  edge.  With my trusty 400D nothing comes out greater than 1936 anyway.
** In camera jpgs have the right EXIF data.  Irfan does not copy exif data when converting from RAW to jpg, only between jpg to jpg.  This is an intended feature not a bug.

Sorry for the verbose answer. Hopefully it helps someone.
Comment: You don't answer the question though. You give a verbose description on your workflow, but it's not answering the question.
Comment: This explenation is NOT an alternative to working with raw files. You convert them to jpg on the first step. From that point i stoped reading couse it is not raw image anymore. I'm not voting down couse im nice :o)
Answer: My suggestion goes for LIGHTZONE: http://lightzoneproject.org/
Unique software that is now developed open source.
It has a useful graphical zones tool hence the name. Furthermore each tool is on its own layer, which allows to achieve some creative effects. Multi platform too.
Comment: I have one more suggestion, this one I haven't tried, it's Polarr web/Chrome editor. It does have experimental raw support. Someone with reputation 10 please update the post on free RAW converters, I think Lightzone deserves to be included.
Answer: I'm a linux user and I was looking for a great open source software like Adobe light room, I used Darktable at first, but soon I realized that It doesn't support NEF nikon d5300 files (Nikon RAW files). I now use Lightzone it is a great piece of software and I'm very happy with it.
Many filters of Lightroom is there for you for free like clarity, HUE, b&w, blur, and so.
Answer: If you can spare fifty quid Bibble is pretty amazing. If not, ufraw and Picasa should cover it.
Comment: Bibble is now Corel's AfterShot Pro and is no longer free.
Answer: If you have a Canon camera that shoots RAW, you should be able to download Digital Photo Professional for free from the Canon website. It's good software - I used it exclusively for three years before moving to Lightroom, and I notice that DPP has had some additional tools added to it since then. You shouldn't have to have the original install disks to do this.
Answer: I use the Free Zoner Photo Studio 17 to edit Canon RAW files. It will open and edit RAW files and then convert them to JPEGs of TIFFs or other file formats. I prefer to retain version 17 on my computer although there is a new version 18 available as a Free download simply because v18 requires you to be connected to the internet for it to work. You can upgrade to a pay version for extra functionality, but at the moment I am finding the free version very useful.
Answer: DigiKam https://www.digikam.org/ is very powerful and feature rich.


SharePoint 2013 List Checkbox validation

Question: I've created a list with Test Check Box column contains two check box choices choice 1, choice 2.
When user's click choice 1 or choice 2 or both and click save a pop-up needs to show up how do i achieve this with validation settings formula on my list.
Answer: Validation isn't done with Javascript, but rather with SharePoint's own validation syntax. What validation does is check if the form is valid according to your rules. It doesn't create popups, but rather a block of red text explaining that something in the form is not correct.
If you want to create a popup, you'll need to add the Javascript into either the NewForm.aspx or EditForm.aspx views with a script editor web part. You can access the views via the ribbon. Below's the points of access for a list library and document library respectively.

From there you can add a Script Editor WebPart, and add your Javascript.
Answer: You cannot use js in the validation, it is not so advanced. In order to achieve that you need to embed custom javascript inside of the form new or edit aspx itself.


I am using Linux kernel 4.8 but still getting 4.4 updates

Question: I am using elementaryOS Loki. I have installed 4.8 from Ubuntu repository.  But I am still getting 4.4 updates. I don't need 4.4 any more since my computer is working just fine on 4.8. How can make 4.4 from appearing in update list.
P.S: I know about package blacklist by apt, but I was hoping for different solution.
Thanks
Comment: I guess you have still a 4.4 kernel installed. What is the output of `dpkg -l |grep linux-image` (in a terminal window)?
Comment: @lemonslice http://sprunge.us/JjDU
Answer: You can remove all Linux 4.4 kernels via:
<code>sudo apt remove --purge linux-image-4.4.*
</code>
However you might want to keep always at least two kernel versions (the running one and a backup in case an upgrade goes wrong).
Comment: I have removed 4.4. Your code needs an edit, `4.4.*` must be between single qoutes


How to find a good financial planner in India

Question: For last few months I am looking for a god financial adviser but cound not found one here in India. I read This SO question but this is not about India. Is there any directory or associations of financial planners in India. A financial adviser is different from a chartered accountant. Right?
Answer: A financial adviser is very different from chartered accountant.
In India the concept of financial advisory is still evolving in recent times. Till couple of years back most of the advisory was from agents or distributors of insurance or mutual fund products tyring to sell their product.
With the recent changes like limiting/removing commissions on most of the financial products and encouraging agents to undergo financial certifications, the future looks good.
Currently most of the leading brokrage houses [Religare, Reliance, Sharekhan, to name a few] along with leading Banks and Insurance houses have rebranded the agents as "Financial Advisors", the chartered accountants have also started offering Financial Advice. However most still lack the skill of advising as per the goals of individual. Rather than taking a hosistic view, the advice is mostly to buy insurance and invset in stocks/funds.
The best way in current situation is to read various magazines and articles and try out a few agents from your Bank or good Brokers and see what value add they bring.
Comment: I totally agree with you. But the problem here is that if agents usually try to sell their products rather than evaluating your goals. I read economic times, especially the articles on personal finance. I think that educating myself on personal finance is the best I can do at this point.
Comment: Unfortunately as of now like you said agents try to sell stuff. It may take sometime [2-4 years] for the market to evolve. Also most of the individuals do not want to pay the advisor a decent sum, as they believe he would make money out of investments... so it would take some time for mind shift of customer to pay someone purely for advice and not buy anything directly from him.
Answer: The financial planning standards board of India has a list of certified financial planners from across India. You can filter it out by categories of state, city, type of employment.
http://www.fpsbindia.org/scripts/CFPCertificantProfiles.aspx
Try choosing an independent person who charges a fixed fee for their consultation. This kind of person won't have any bias toward funds and will keep your financial goals and welfare in mind. Also look at their profiles and what they have written, because that will be a first indicator of their quality of work.


Can you give me a piece of advise of the network sructure that would be suitable for my task?

Question: I have 2 small images. They are basically the same, but differ in rotation and size. I should estimate the parameters for affine transform to get them similar. What network structure can be suitable for this task? For example, those based on convolutional networks did badly, because the pictures are too small.
Comment: Of they are exactly the same and differ by affine transform you don't need NNs. If they are similar I think any NNs would do (try using relu) though.
Comment: Does it have to be with NNs or do you want to use image processing tools
Answer: Instead of NNs, you can use RANSAC algorithm to calculate homography matrix, but first you need to find feature points. However, if your images are blob-like, you may not get such a successful results. Here some presentations for better understanding: cs.umd notes and csail.mit notes
(Also, there might be better image processing tools.)
Answer: Just use IMGAug library for Applying the 'zoom' augmentation on the images and a convnet (or even MLP) would have no problem in this task. Zooming on the image would be more than enough to use as, as long as your zoom is of sufficient power.
So apply "zoom" of the same factor on all images, make them bigger, and Convolutional Neural Networks would do fine. Also, If color is not an important feature, then you would be better off rescaling images b/w 0 and 1 and making them GrayScale


Would cobalt make a moon blue?

Question: Would abnormally high levels of cobalt on a moon cause it to appear blue to those on the planet it orbits?
Answer: Elemental cobalt is not blue

The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal.

If you want to have blue with cobalt, you need to have cobalt blue

Cobalt blue is a blue pigment made by sintering cobalt(II) oxide with alumina at 1200 °C. Chemically, cobalt blue pigment is cobalt(II) oxide-aluminium oxide, or cobalt(II) aluminate, $CoAl_2O_4$. Cobalt blue is lighter and less intense than the (iron-cyanide based) pigment Prussian blue.

or Prussian blue

Prussian blue is a dark blue pigment produced by oxidation of ferrous ferrocyanide salts. It has the chemical formula $Fe^{III}_4[Fe^{II}(CN)_6]_3$

Answering your question, if you have abnormal levels of cobalt alone you won't get any blue. If you have the right cobalt compounds you might end with a blue looking moon.
I am not sure about their stability in space conditions, though.
Comment: There are plenty of aluminum oxides on our moon.  I am sure cobalt would join the party if there were some up there.  Without a dream in its heart.  Without a love of its own.
Answer: Cobalt occurring naturally does not appear blue.
You can see from this picture of cobalt ore as well as three of the most common naturally-occurring cobalt sources on Earth, cobaltite, glaucodot, and skutterudite that none of them appear blue.

Would cobalt make a moon blue?


Which type of Machine Learning is used in robots?

Question: Which type of Machine Learning is used in robots? Is it supervised learning or unsupervised learning or Reinforcement learning?Especially the robots that were sent in space?
Comment: Hi, could you put more details to your questions? Owing to the definition of a "robot" there is a myriad of robots like autonomous vehicles, drones or thermomix. Please clarify the question and maybe add some examples of robots you bear in mind.
Comment: I don't think space rovers use any ML, here is a fresh article from a couple of days ago from NASA discussing about using ML for VIPER end of 2024.
Comment: Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer.
Comment: Link [Part 1: Artificial Intelligence and NASA's First Robotic Lunar Rover](https://blogs.nasa.gov/artemis/2023/12/01/part-1-artificial-intelligence-and-nasas-first-robotic-lunar-rover/#:~:text=%E2%80%9CIt%E2%80%99s%20a%20tool%20that%20allows%20us%20to%20use,AI%E2%80%99s%20outputs%20as%20a%20baseline%20for%20mission-related%20decisions.)
Answer: The sort of deep neural networks most commonly referred to today as "AI" are going to be of limited use on something like a rover.  When you are programming a rover, your software needs to be 1) reliable and 2) lightweight, neither of which modern "AI" models really are.  Any mistake that a rover makes needs to be completely comprehensible.  You need to be able to work back through the processes it used to make that decision and figure out exactly where it went wrong, and you need to be able to stick as much as possible onto the relatively sparse hardware present on the rover.  However, there are a couple of caveats to this.
The first is that neural nets aren't the end all and be all of AI, and if you want to work in fields like image and signal processing, you need to also understand the more basic methods used to do things like extract information from an image.  In a professional context, even if you are working with neural nets, these methods still need to be used in conjunction with them to do anything cool anyway.  The solution to a problem is rarely "feed the data into a neural net and swirl it around until it does something useful".  You usually need to employ a bunch of additional optimization and feature selection techniques alongside your pretty dense matrix.  And when it comes to these sorts of things, rovers (and pretty much any robotics application) will use them too, whether there is a neural net to be found or not.
The rover has cameras mounted on it, for instance, and it needs to be able to use the inputs coming in from those cameras to "see".  This means identifying objects of interest, stitching images together to extend its field of view and provide it with depth perception, and figuring out where obstacles are, among numerous other tasks.  All this stuff uses GOFAI (Good Old Fashioned AI), and the techniques involved remain foundational to robotics as well as to more modern AI techniques.
Looking into the techniques behind these sorts of basic computer vision tasks might be an interesting start if you have an interest in robotics.  Mess around with convolution filters to isolate an object, like a coin or baseball card, in an image.  Look into feature selection algorithms like SIFT, ORB, and BRIEF, and use that information to stitch two images of an object from different angles into a panorama.  Maybe try taking those feature vectors and applying a technique like Locality Sensitive Hashing to them, and then using those hashes to return a neighborhood of images most similar to a given query image.  All these sorts of techniques are used by everything from the Mars Rover to your Roomba to find their way around a space, figure out what's in front of them, and keep from bumping into things, and they are also used by AI algorithms to do things like give you song suggestions on Spotify or find your face in order to put a duck bill on it on Tik Tok.
The second caveat is that, while I doubt AI will be on rovers any time soon, I am sure it's already finding applications in mission control.  Back on earth where you have limitless processing power and memory, it would be about as silly not to employ AI as it would be to employ it on the limited hardware of a Rover stranded on mars.  These applications are likely similar to other data science applications, and if you are interested in this sort of thing I'd say go play around on kaggle.  Whatever you decide to play with will end up being useful.


Where can I find the api supported by kernel32.dll?

Question: Where can I find all the functions provided in kernel32.dll? I was able to find some functions here, but I don't know how authentic that site is. Is there an authentic site that lists out all the available functions with proper documentation. I searched online but couldn't find any.
Answer: Why do you specifically want to know about the functions in kernel32.dll? For legacy reasons that dll is still the entry point for a lot of windows api functionality, but the windows API is now far FAR larger than the 3 subsystems Windows 3.x offered (kernel, user and gdi).
The System Services section in MSDN covers the APIs exported from kernel32.dll, and many more.

As MSDN no longer documents just the Kernel32 exports in a single list, you could use DumpBin to extract a list of all the exports... and then search for the function on MSDN.
Comment: It is because I am analyzing some old code that is using these functions.
Comment: Well, Microsoft no longer documents the kernel32 export list in a single document.
Answer: I found this link -
http://download.microsoft.com/download/2/E/9/2E911956-F90F-4BFB-8231-E292A7B6F287/GRMSDK_EN_DVD.iso
It's the official Microsoft documentation.
Comment: Link now broken.
Answer: The functions available in kernel32 change per version of Windows. New functions are added and some are taken away every release.
If you want a canonical list on your machine, fire up Depends.exe (ships with the Windows SDK) and load kernel32.dll into it. All of the kernel APIs are implemented as exports on Kernel32.
Given a function name, visit the MSDN documentation at msdn.microsoft.com. This is the official site that documents all of Microsoft's official Windows APIs.


Solve system of linear ODEs

Question: How do I solve a linear ODE system in $n+1$ dimensions, i.e. $∂y/∂t+p(t)y=q(x_1,….,x_n,t)$
Where $y=y(x_1,….,x_n,t)$  and initial conditions are $y_0=y(x_1 (0),….,x_n (0),0)$?
I am familiar with use of integrating factor in one dimension, but can't adapt it.
Comment: Thanks for your assistance Tony. I think your last sentence pinpoints my problem. My initial condition is an expression for y when t=0. What does "determine the bounds of integration" mean here in practical terms?
Answer: Integrate p(s) from 0 to t. Then put this in the exponent and you will have an integrating factor. Multiplying both sides by this will give you the partial derivative of the product (Integrating Factor x p(t)) with respect to t on the left hand side. You can integrate this over t and the right hand side over t and you will get a solution. You can use the initial conditions to determine the bounds of integration.

Solve system of linear ODEs


Are there any wars in the world not involving terrorism?

Question: Most wars you hear of today are somehow linked to terrorism and state sponsored terrorism for the sake of some political agenda. Are there still any wars remaining between sovereign states?. If not, what was the last war of this kind?
Comment: This is unanswerable without a specific definition of terrorism. Providing local insurgents with all kinds of support has been a standard strategy in war for quite some time now. Commando operations could be classified as terrorism as well, and often are by the target of the operation.
Comment: Phillipines is threatening war with Canada over ... trash!   https://www.cnn.com/2019/04/24/asia/duterte-canada-trash-intl/index.html
Comment: @CrossRoads Do threats really count? North Korea has been threatening America, India has been threatening Pakistan.. It's not a war?
Comment: Do you mean terrorism as a non-denominal tactic, or terrorism as a weasel-word for jihad?
Comment: A war between militaries and not between insurgents and armies
Answer: Even ignoring the terrorism question, this is hard to answer because official declarations of war don't happen so much recently.
Russia vs Georgia in 2008 was definitely a war by most standards, with regular army units fighting each other.
In 2016 there were four days of fighting on the Armenia Azerbaijan front. Officially this war never ended.
But then neither did the Korean war, and there were sporadic incidents in that as well in recent times.
Comment: Neither has the second world war. There was no peace treaty.


Uses for Force Touch in the Xcode editor

Question: Are there any special uses for the Force Touch trackpad on Apple's newer laptops in the Xcode source editor? I have tried to use it for various things but Force Touch always seems to do the same thing as a regular click. It would be cool to be able to force touch a variable and have that open the refactor menu, for instance. Is such a thing possible?
Answer: In Xcode 10 you can use Force Touch inside Interface Builder to select from a list of views and windows under the cursor (i.e. topmost view, its ancestor and all the way to the window):


How can I get number of API transactions used by Watson NLU?

Question: AlchemyLanguage used to return the number of API transactions that took place during any call, this was particularly useful when making a combined call.
I do not see the equivalent way to get those results per REST call.
Is there any way to track or calculate this? I am concerned about things like some of the sub-requests like when you ask for sentiment on entities does that count as two, or one plus an additional call per recognized entity?
Answer: There's currently no way to track the transactions from the API itself. To track this (particularly for cost estimates), you'll have to go to the usage dashboard in Bluemix. To find it: sign in to Bluemix, click Manage, then select Billing and Usage, and finally select Usage. At the bottom of the page you'll se a list of all your credentialed services. Expanding any of those will show the usage plus total charges for the month.
As far as how the NLU service is billed, it's not necessarily on a per API request as you mentioned. The serivce is billed in "units" and from the pricing page (https://console.ng.bluemix.net/catalog/services/natural-language-understanding):

A NLU item is based on the number of data units enriched and the
  number of enrichment features applied. A data unit is 10,000
  characters or less. For example: extracting Entities and Sentiment
  from 15,000 characters of text is (2 Data Units * 2 Enrichment
  Features) = 4 NLU Items.

So overall, the best way to understand your transaction usage would be to run a few test requests and then check the Bluemix usage dashboard.
Answer: I was able to do a simple test, and made calls to a set of highlevel features and included sub-features. And it appeared to only register calls for the highlevel features.


Does Ubuntu Touch multitask like a desktop Ubuntu would?

Question: I recently purchased a nexus 7 and would like to put Ubuntu on it. Regular Ubuntu is no longer supported for this device, only Ubuntu Touch. If I install Ubuntu Touch on my tablet, and plug in a mouse and keyboard, will it function more or less like a desktop version of Ubuntu? ie multiple windows can be open at once on the desktop laying over each other, rather than how Android and other mobile OSes only allow one full screen application to be "running" at once (simplification).
Answer: Switching to windowed mode is possible with Unity8 15.04 version.
Comment: With a bit of googling, this is enabled using `gsettings set com.canonical.Unity8 usage-mode Windowed` and disabled using `gsettings set com.canonical.Unity8 usage-mode Staged` feel free to add this to the answer. Cheers!


What is the Biblical basis for sharing the cup at communion?

Question: In our church everyone usually drinks out of the same cup at communion. Is there a scriptural reason for this?
Answer: There are two main reasons:

Most Christians want to think of themselves as continuing the same practices as the early church did and even the very Last Supper itself. Because they shared one cup in the Jewish Passover, so many Christians think it is most appropriate to share one cup now.

There is a passage in 1 Corinthians which describes the emblems of communion as symbols of Christian unity. Though it explicitly only says that the bread is one, it's easy to see how the meaning would also apply to the cup.

1 Corinthians 10:16-17 (NIV): Is not the cup of thanksgiving for which we give thanks a participation in the blood of Christ? And is not the bread that we break a participation in the body of Christ? Because there is one loaf, we, who are many, are one body, for we all share the one loaf.
Answer: There are passages, plenty of them, in which the cup containing the fruit of the vine is referred to in the singular, but Luke indicates that this is synecdoche.
In Luke 22:17-20, Jesus starts by directing the gathered disciples to divide up the Cup (meaning its contents), with the later text--in conjunction with the narratives in the other Gospels--indicating that they did not consume it until after eating of the broken bread; so individual containers were employed.
What I gather from this is that both practices are authorized, but neither is mandated beyond the simple fact that each congregation must do one of the two.