Can rhododendrons be cut back?

Question: I have a situation where a row of rhododendrons in front of the house is overgrown and getting large. I was told by someone else that they need to be removed and replaced with smaller rhododendrons. Is that true, or can they be cut back?
Comment: Andre, are you dealing with 'line of sight' issues within city or development regulations?
Answer: Rhododendrons can absolutely be cut back, no matter what the size. We've been pruning ours for years, and some of our bushes are 10ft tall. As long as they're not diseased, or too close to a structure, like the house, disturbing the roots is not necessary. They even thrive extremely well grouped closely together with other shrubs and trees.
Here is a good article explaining the three most common ways to prune the rhododendron. Drastic pruning can also be called rejuvenation pruning. The best time to do it is in the winter.

Rejuvenation pruning is best used to restore shrubs that have become leggy, overgrown, or otherwise unattractive. Many rhododendron species and hybrids can be severely pruned and come back as good as new.
Rejuvenation pruning removes most of the branches of the plant, initiating the rise of vigorous flushes of new growth from previously leafless old stems. The new growth matures into a new framework of branches that can then be shaped over the years to produce a stunning shrub.

If you want to do it gradually, start by cutting back the largest branches to the trunk, but leave them in a staggered or random positions, so you'll still have something to look at. However, if you really need to cut the whole thing down, you can do so, as you've already been told by @Tim Nevins. The same article explains that you can cut the entire plant to within 6 inches of the ground.
The reason it works is because rhododendrons actually have buds all the way down to the base, even if what you see only looks like wood. Look closely for small pink areas, which are risen and look like buds. Cut above them, and they'll start the growing process for the new branches. It can take over a year to produce flowers though, but at least you'll have a sturdy plant, and not have had to dig anything up!
From the same source I linked to above:

Don't worry about making mistakes: Rhododendrons are very forgiving—even if you drop a tree on them.

Here are some pictures of our bushes. They're different varieties and colors. They've been pruned many times to different sizes through the years, and had numerous things growing under and around them, and they just keep growing! We have them checked regularly by an arborist, and unless he saw something sick, we wouldn't even consider digging them up!
Click on the pictures for closer view.
Answer: You can prune a rhododendron with a chainsaw and it will come back. I lived in Washington state for a number of years and did/saw this multiple times. Was the person who said to replace your big plants with small ones selling rhododendrons by any chance?
In all seriousness, leave a foot or so of the main stem and stand back.
Comment: I worked in Washington, the Seattle area for a couple of decades.  You are correct, chainsaw those rhododendrons down and they will live but their beauty will be gone.  Except for flowering.  Flowering is but a minuscule part of their beauty.  Gorgeous branching.  I treat most rhodys like small trees and open them up to display the branching which also helps the plant have more vigorous vegetation and flowers and far less disease, fungus and insect problems.  Thinning works well.  Your plan would work if indeed a few feet shorter is necessary, yes?
Comment: Did you ever visit Big Trees in Snohomish?  They charged people to take out mature specimens and then they sold these specimens for thousands and thousands of dollars.  Some people are able to purchase a beautiful Japanese Maple, 10'x10'?  ....for $12,000.  Lots of rich people in the Seattle area.  I can't imagine having large rhododendrons and chainsawing them down.  I know, you were doing a service I was way too knuckleheaded to do what the customer wanted when what they wanted wasn't the right decision.  ha ha ha
Answer: Please please do not take a chain saw to those rhododendrons, please!  Yeah, they will be shorter but ugly ugly ugly for years and years.
I've renovated rhododendrons for a living and kinda blew the owners away with the amount of thinning I did...in 6 months they were my biggest fans.  Rhododendrons are small shrubs, medium shrubs, large shrubs like yours that are also classified a small tree.  Gorgeous.  They should look like beautiful, humongous Bonsai.  To die for, worth their weight in gold (literally).
You have to send a picture of your rhododendrons and the environment, need to know why they are too tall, too thick, too wide for your needs.  Do you remember which rhododendron they were?  A tag left over somewhere?
Doesn't matter.  A mature healthy plant is so very valuable. If I could see what you are dealing with and your landscape I would love to help you fall in love with those shrubs/small trees.
The picture borrowed for visual aid taken by Van Den Berk Nurseries is at Pinterest. It comes from the website of the Van Den Berk Nursery. It can be found in their Rhododendron Guide.
Comment: Hi stormy! Thanks for giving attribution to that picture. It was from Pinterest, though, which is membership site. Since I'm not a member, I couldn't get a good look at the picture. I added the link to the nursery where it came from, and their rhododendron guide which has the picture in it. I hope that was helpful, and didn't deface your post!
Comment: Excellent, Sue.  I appreciate your help...

Can rhododendrons be cut back?


How are capacitor voltage ratings chosen

Question: I'm reading a user document of a dev board. On page 12, there is an explanation of the power management subsystem. The board VBUS and VBAT lines have a decoupling cap rated at 6.3V, whereas the output voltage rail has a 10V rated capacitor. What affects the decision of putting a higher voltage rating cap on the the rails. Would it affect the circuit if all caps were rated 10V?
Comment: There is no reason for a well-designed internal regulator to demand this specific voltage value, and even not specifying its ESR. So I think this requirement is BS, both 6.3V and 10V should work just fine on 3.3V rails, just 6.3V is less stable in value, but cheaper.
Answer: Real capacitors are far from ideal and different things affect their capacitance. For example, there are multiple types of ceramic capacitors that use different dielectrics and they all behave differently under temperature and DC-bias.
Some ceramic capacitors like Y5V can vary as much as -82% to +22% over their temperature rating! I'm not sure where these are used. I assume garbage consumer electronics. They come in very large capacitances for their physical size though...and they better with that -82% fluctuation.
X5R and X7R capacitors are better in that they vary about +/-15% over their temperature rating. These are typically used for decoupling for anything that matters.
But every type of ceramic except for C0G suffers from DC-bias effects. So if you apply a DC voltage to it (as decoupling capacitors are used) their capacitance decreases. Sometimes by 50% as you get near their voltage limit.
Don't use C0G for decoupling though. They are expensive and physically large for the capacitance they provide. They are also very low ESR (resistance) which is normally good but in decoupling applications can produce ringing. C0G is voltage bias and temperature stable and suffers from no piezo effects (other ceramics will produce a voltage under vibration which results in noise) so they are used in timing and signal path applications like filtering.
You can compensate for this by picking a capacitor rated at the size you want but pick a higher voltage than what you are running it at. Or you can pick one near the voltage you're running it at but choose one with a higher rated capacitance.
There are also tantalum capacitors (not ceramic capacitors) that are very sensitive to over-voltage and can also suffer reduced lifetime so you use them at half their voltage rating so bad things don't happen.
For electrolytics de-rating their voltage can extend their lifetime (also true of other capacitor types).
Comment: Thanks! I'm not familiar with the term C0G - can you elaborate?
Comment: It's just the code for a type of dielectric used in C0G/NP0. Two codes, same thing. Just like Y5V, Y5R, X5R, X7R, X8R, X8S, each digit tells you the temperature range and stability of the capacitor. Scroll down the wiki for the code tables.
https://en.wikipedia.org/wiki/Ceramic_capacitor#Application_classes,_definitions
Answer:
greater Vmax voltage is better for reduced supply sensitivity to capacitance drop and often lower ESR but at the expense of size limitations for a 0402 preferred package size.

The short answer is these choices offered the design the best bang for the buck, meaning the lowest impedance choosing the biggest uF in the smallest size to limit ESL [nH], ESR [mΩ] and thus raise self-resonant frequency, SRF. It does not mean you will be able to find these easily and going to a bigger voltage may demand a bigger package that may reduce ESR but may lower SRF below the switcher spectrum of x MHz for example, which may make the cap look like an inductor.
offering limitations
You must spend enough time to understand the many non-ideal characteristics of capacitors to remember that Vmax - uF - ESR - $cost - footprint size ALL have tradeoffs
Then spend much more time to be able to have an in-house number with qualified parts that match certain expectations for all the above. Start by reading more datasheets.
C0G won't work here because C0G or NP0 is low-density stable temp coeff. with a low but stable dielectric constant.    NP0 means -/+0 ppm/'C {+/-30'ppm} so you cannot get big uF in NP0=C0G material. ( see 1st table above for C0G)
See page 32/34 to see the BOM, you will find the descriptions of 0402 6.3V caps @ 10uF
Other standard material codes are Y5Z,X5R,X7R  but ther are  zero  or . Here Dialog has chosen the biggest value caps in the smallest package size (402 or 603) to provide the lowest impedance at the frequency of current where \$I_C=C*dV/dt\$ and \$f_{-3dB}=0.35/t_R\$ for rise time \$t_R=dt\$ and ripple voltage \$dV=ΔVpp\$ so $$C=\dfrac{I_C*0.35}{ΔV*f_{-3dB}}$$
Comment: Wow, thanks for the detailed response! I have a lot to read up on
Comment: I had to do the same for many days/weeks when I start reading Mil-Stds for caps, crystals etc for aerospace when I graduated.
Comment: Keeping track of packaging effects on everything else is the worst.
Comment: Yes and out of 0.5 million ceramic caps listed on D-K none are 10uF 0402 like item 25  not even 4V yet  Mouser lists them, with 0 stock and 24 wk lead time


Advanced Search Link

Question: I have enabled the link to Advanced Search from Home Page just beside the searchinput box. I want to style this link and change the colors. Please let me know how do I do this?
Comment: What version of SharePoint are you running?
Answer: You will need to override the CSS for the link, but as I'm not sure which version of SharePoint you're running, I can't be more specific.
Your best bet would be to use an inspector tool for whatever browser you're using (Firebug, IE Developer Tools, etc) and select the Advanced Search link element. This will tell you which CSS class to change.
Comment: SharePoint 2010

Advanced Search Link


CRON RUNNING OK?

Question: I write for problem "cron not running"
I use wordpress 4.9.6 and civiCRM 5.1.2
Perhaps no quotation mark is required:
wget -O -q -t 1 https://my-site/wp-content/plugins/civicrm/civicrm/bin/cron.php?name=my-name&pass=my-pass&key=my-site-key
and above all: civiCRM 5.1.2 requires php 7.0 or higher. Perhaps my hosting service solved the problem by entering PHP version 7.1.16
Screenshot by civi page system status
Comment: Hi, thanks for contributing. StackExchange is a question and answer format but your post is not a question and so has been marked down.  You could rephrase your post as a question/problem and then provide an answer. Note though that there are existing questions about cron not running so it would be better to review those and see if the solution you found is mentioned.  If it is, upvote that answer. If not, add your own answer.
Comment: What Aidan said is correct. I wanted to let you know that any status that is green is functioning okay for now. It just means Cron is running okay and that PHP is up to date but you might want to upgrade it in the future.
Answer: The requirements for CiviCRM are php 5.5 or greater for version 5.1.2 https://docs.civicrm.org/sysadmin/en/latest/requirements/#php-version
If you hosting company had an older version upgrading to 7.1 would have solved that issue.
Comment: **why is the state red again?**
what is not working? I can not solve this problem permanently
thank you

CRON RUNNING OK?


Bitcoin Mining with Poweredge Servers?

Question: From a previous business, I have 5 Dell Poweredge 2850 Servers, each with 2 Intel Xeon 3.4 Ghz processors. I also have 2 2950's, a huge 7150, and few other smaller 1 U Dell servers. All but 2 of those machines are just sitting there in the rack and not even turned on right now. I have seen CPU miners and know that these are not optimal, but have considering making 5 mining servers out of the 2850's to just see what happens. My power bill increases around $400 a month when running all of these servers/switches/UPS/Firewall/etc. (more in the summer than winter of course). I have all the infrastructure and hardware to setup these machines, but I can't seem to find any data on potential earnings with Xeon processors to see if it would be worth my time or the extra power to build miners out of these machines. I understand that with the difficulty going up the earning will continue to decrease, but if anyone could provide some rough potential numbers or suggestions for further research, it would be appreciated.
Comment: CPU and GPU mining has been outdated by ASIC mining.  There isn't much you can do with Bitcoin perse with that hardware besides vanitygen.
Comment: I would be very surprised if you manage to mine more than 0.5 BTC/month with those.
Comment: You can use those to mine primecoin right now.
Answer: If you could get recent GPUs (Radeon HD 6850 or newer) for very, very cheap, you might be able to make a couple of Bitcoin per month. It may not be worth it, depending your electricity costs.
Use these tools to help guide you to an informed decision:

P3 Kill A Watt power meter, to find your actual power consumption
Mining hardware comparison, to find a GPU that will work in your system and plug its hashrate into...
Mining profitability calculator, to calculate what your break even or profit point will be.

vanitygen is probably your best bet given the equipment that you already have.
Answer: Two or three years ago, yes, you might've mined some BitCoins with this equipment.
Now it's all obsolete, compared with ASIC-based equipment that outclasses it by 3 or 4 orders of magnitude in hash-specific processing power.
You could run all your current equipment for a month and probably not even mine a single coin.
Answer: I would try running SCRYPT based miners. I have 3 poweredge servers to set up and thats my take for now.
Comment: Can you expand this at all to indicate what the asker should expect as far as performance goes?

Bitcoin Mining with Poweredge Servers?


compile/run Common LIsp from the Mac Terminal

Question: Is there a way to do this? I've been using Slime to learn Lisp, and I would like to start building larger projects which means (I think) that I would have to start writing some .lisp files.
Comment: what gives you the impression that you cannot write Lisp files and Lisp applications with SLIME?
Comment: Rainer is right. Just press `C-c C-k` in a Slime Lisp buffer to compile and load the file, check my answer for more details.
Answer: I think your best bets for Mac Common LISP are the LispWorks Personal Edition or SBCL.
Assuming you've got SBCL installed, you can create a .lisp file using a text editor (emacs would be the traditional choice):
(defun test ()
"Hi!")

Then you can run a lisp interpreter in a shell:
bash% sbcl
This is SBCL 1.0.29, an implementation of ANSI Common Lisp.
More information about SBCL is available at <http://www.sbcl.org/>.

SBCL is free software, provided as is, with absolutely no warranty.
It is mostly in the public domain; some portions are provided under
BSD-style licenses.  See the CREDITS and COPYING files in the
distribution for more information.
* (load "test.lisp")

T
* (test)

"Hi!"
*

The shell could either be a mac terminal window or an inferior lisp interpreter running in emacs.
Comment: Hey rmalouf! SBCL's option --script  can be used to execute files directly w/o REPL.
Answer: Slime is designed to support writing Lisp files, including definition finding, online documentation, name completion, compilation, and more.  Perhaps you should take a look at the manual, chapter 3 (using slime-mode).
Answer: I think it is a bit hard to tell what you are really asking for.
You can compile and load a whole Lisp file in Slime by using C-c C-k in the buffer, and then use it from within the Slime REPL, so you don't even have to run LOAD in the REPL.
Then, there are solutions for shebang lines known from unices that will work in the OS X shell, if you want to run your Lisp programs as scripts from the command line, but those differ from implementation to implementation.
A possibility for building executables, which then can be run from the command line, is loading the relevant code into your Lisp image, then saving that image with the loaded code. Those images may be made executable, executing a given function on startup (think main). This possibility also differs for implementations, so without mentioning your implementation of choice, you will have to look it up in its documentation.
Now, since you are asking about "building larger projects" specifically, my advice would be to get acquainted with a system definition facility. A lisp system basically is a kind of "project", a few files with code, package definitions, and a system definition. I will give you a little example for ASDF, which is (as far as I can tell) the most popular one in the open source world.
(defsystem my-system
  :name "my-system"
  :version "0.0.1"
  :author "hedgehogrider"
  :license "BSD"
  :description "bla bla bla"
  :serial t
  :components ((:file "packages")
               (:file "code")))

Now, you would put this in an asd file, say my-system.asd, put your package definitions in packages.lisp, your functionality in code.lisp, and then, given you set up ASDF properly, you would be able to compile and load your system in the Slime REPL by pressing ,l my-system. Alternatively, you could enter (asdf:oos 'load-op 'my-system) (or, for more recent versions of ASDF: (asdf:load-system 'my-system)) at the REPL.
In order to make this work, you will have to install ASDF for your Lisp implementation, if it is not shipped with it, and the directory containing your asdf-files will have to be put in asdf:*central-registry*. One easy solution is to symlink your asdf-files to one central directory, but there are other possibilities. Check the ASDF documentation or other tutorials to learn more about ASDF.
Answer: Yes, you will want to write your own Lisp files instead of relying on images.
I recommend CLISP for OSX for an out-of-the-box experience. It has a nice REPL experience.
Professional development done with F/OSS today generally uses SBCL or CCL.


Python lettuce test results in XML

Question: I'm trying to get an xml report of the results of my behavior tests running in the lettuce framework. According the --help for lettuce, you should use the switch --with-xunit. I've done that (and also used --xunit-file) but no report is generated. I tried reinstalling lettuce but still no luck. How can I get it to generate this report?
Comment: You'd be better asking this on the Lettuce users' mailing list.
Answer: I know this is really late, but I made a boilerplate project for lettuce and python (and jenkins).
This is how I solved it:
have coverage talk to lettuce
If you like an example, you are welcome to poke around here:
https://github.com/stephas/jenkins-lettuce
Answer: This was actually something simple: the folder the tests were running in were owned by root so I needed to run the tests with sudo in order for it to generate the report.

Python lettuce test results in XML


Controlling images of nodes in a TreeView

Question: I am trying to make a folder explorer using TreeView control. now, I added an ImageList with two images - one for a folder and the other for selected folder. I used the 'BeforeExpand' event to change the icon of the current node (folder). The problem is that I dont know how to change it back when the user selects other folder... what event can I use? Maybe I dont use it right... ?
Comment: is this wpf or winforms?
Answer: I'll assume here you only want to change the TreeNode image shown when a given Node is selected. And I'm not going to deal here with the issue of showing 'folder icons for every TreeNode with Child Nodes: I think if you grasp what's going on here, you'll have no problem adding a (third) image and "doing the right thing" to make folders explicit: and then you can extend that, if you wish, so Nodes with "no child nodes" can have different icons for selected/unselected.
(1 add an ImageList to your Form with two images: the image with index #0 will be the default (unselected) TreeNode image.
(2 add an AfterSelect Event Handler to your TreeView : change its image to the "selected" image.
<code>    private void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
    {
        e.Node.SelectedImageIndex = 1;
    }
</code>
You'll note that as the selected Node is changed: the previously selected TreeNode image will automatically revert to use its default image (index #0 in the ImageList).
Note : imho it's important here to distinguish between expanding a TreeNode in a TreeView and selecting a TreeNode in a TreeView: you can expand any TreeNode (with child nodes) by clicking on the "+" icon : but that will not select it. Double-Clicking will, of course, both Expand and Select.
Answer: I think you have to keep a reference of the last node expanded, so you can change it later
Answer: hmm I don't know if I understand correctly but actually, in a folder explorer context, if the user expands another node, you don't need to do any specific action on the node you have previously expanded. If the user clicks again on it, then you can use the BeforeCollapse event to change it back. Would it fit your needs?


Eigenvector corresponding to eigenvalue $ 1 $ of a stochastic matrix

Question: I am trying to justify fact $ 5 $ in this link which states that if $ A $ is a column stochastic matrix, then $ A $ has eigenvalue $ 1 $ and a unique eigenvector such that all entries are either negative or positive. I have successfully proved that $ A $ has an eigenvalue $ 1 $ but still stuck on the second part of the fact. It seems that this is the Perron Frobenius theorem, but the proof for this theorem requires materials that are beyond a first course in linear algebra that I haven't learned about, so is there any way to prove this fact without using the PF theorem?
Comment: A crucial assumption is missing in your question (but not in the mentioned fact): in fact 5, $A$ is assumed to be **positive**. If this requirement is removed, the "fact" is no longer a fact. Counterexample: every positive or negative vector is an eigenvector of $A=I_2$ corresponding to the eigenvalue 1.
Answer: For one thing, the eigenvector is unique up to scalar. That's easier to prove for the transpose $A^T$: the only eigenvectors for $1$ are multiples of $(1,...,1)^T.$ If $v$ is any eigenvector, then let $k$ be an index such that $v_k$ is maximal; then $$v = A^T v, \; \mathrm{so} \; v_k = \sum_{i=1}^n a_{ik} v_i \le \sum_{i=1}^n a_{ik} v_k = v_k,$$ and equality implies that all $v_i$ equal $v_k.$
Now that we know this, let $v$ be an eigenvector of $A$. It's enough to show that $|v|$, whose components are the absolute values $|v_k|$, is also an eigenvector.
I will use the notation $v \le w$ and $v < w$ to mean that $v_k \le w_k$ or $v_k < w_k$ for all $k$.
Define $y := A|v| - |v| \ge |Av| - |v| = 0.$ Assume that $y \ne 0$; then $Ay$ and $A|v|$ both have strictly positive elements, so there is $\varepsilon > 0$ with $Ay > \varepsilon A |v|.$ Then $$Ay = A (A|v| - |v|) > \varepsilon A|v|$$ implies $$A^2 |v| = A (A|v| - |v|) + A|v| > (1+\varepsilon) A |v|.$$ By taking the $\ell^1$-norm (i.e. sum of elements), it follows that $$\|A |v|\|_1 = \|A\|_1 \cdot \|A |v|\|_1 \ge \|A^2 |v|\|_1 > \|(1+\varepsilon) A |v|\|_1 = (1+\varepsilon) \|A|v|\|_1.$$ This is a contradiction. So $y = 0$ and $|v|$ was already our eigenvector for $1$.


Android, hook mount as flash drive

Question: There are way for:
On USB connect to PC (or other flash drive reader) - hook process and allow access only specified files and folder on android (custom store)?
Answer: Only by creating your own firmware.
SDK applications cannot interfere with either the USB Mass Storage mode or the USB Media Transfer Protocol forms of mounting Android external storage as drives on a host computer.

Android, hook mount as flash drive


Why is Bitcoin gaining value while so many other cryptocurrencies are not?

Question: Every time I find a new cryptocurrency, I look at the price charts and almost every time it's constantly losing value. Ether and Bitcoin are the only exceptions, and have gained value on the long term. Why is that?
Answer: There is this classic bootstrapping problem. To make a successful cryptocurrency it needs:

Miners (so that it's secure)
Users (to attract miners, users also want it to be secure)
Value (to attract users and miners)

So new cryptocurrencies need to find a way to jump-start all those things at the same time, which it turns out- is not easy.

Here's a great description of it from Bitcoin and Cryptocurrency Technologies by Arvind Narayanan, Joseph Bonneau, Edward Felten, Andrew Miller & Steven Goldfeder:

Getting a cryptocurrency off the ground

Another subtle concept is that of bootstrapping. There is a
tricky interplay between three different ideas in Bitcoin: the security of the block chain, the health of the mining ecosystem, and the value of the currency. We obviously want the block chain to be secure for Bitcoin to be a viable currency. For the block chain to be secure, an adversary must not be able to overwhelm the consensus process. This in turn means that an adversary cannot create a lot of mining nodes and take over 50 percent or more of the new block creation.

But when will that be true? A prerequisite is having a healthy mining ecosystem made up of largely honest, protocol‐following nodes. But what's a prerequisite for that — when can we be sure that a lot of miners will put a lot of computing power into participating in this hash puzzle solving competition?

Well, they're only going to do that if the exchange rate of Bitcoin is pretty high because the rewards that they receive are denominated in Bitcoins whereas their expenditure is in dollars. So the more the
value of the currency goes up, the more incentivized these miners are going to be.

But what ensures a high and stable value of the currency? That can only happen if users in general have trust in the security of the block chain. If they believe that the network could be overwhelmed at any moment by an attacker, then Bitcoin is not going to have a lot of value as a currency. So you have this interlocking interdependence between the security of the block chain, a healthy mining ecosystem and the exchange rate.
Because of the cyclical nature of this three‐way dependence, the existence of each of these is predicated on the existence of the others. When Bitcoin was first created, none of these three existed. There were no miners other than Nakamoto himself running the mining software. Bitcoin didn't have a lot of value as a currency. And the block chain was, in fact, insecure because there was not a lot of mining going on and anybody could have easily overwhelmed this process.

There's no simple explanation for how Bitcoin went from not having any of these properties to having all three of them. Media attention was part of the story — the more people hear about Bitcoin, the more they're going to get interested in mining. And the more they get interested in mining, the more confidence people will have in the security of the block chain because there's now more mining activity going on, and so forth. Incidentally, every new Altcoin that wants to succeed also has to
somehow solve this problem of pulling itself up by its bootstraps.
Answer: The simple answer is that this is a product of the network effect.  Bitcoin has a massive advantage in that it was the first blockchain-based currency, so it is the gold standard of the technology.  A competing cryptocurrency needs to not only be better than Bitcoin, but be much better than Bitcoin.  It's not enough to be slightly better, as the momentum Bitcoin has in the market outweighs slight advantages other coins may offer.
As you've identified, the only cryptocurrency that has made any headway in competing with Bitcoin is Ethereum.  This because the Ethereum blockchain does not attempt to compete with Bitcoin as a currency, but rather as a smart contract platform.  In that regard, Ethereum provides a significant advantage over Bitcoin.  However, Bitcoin still has proven to be a more robust and trustworthy currency, so Ethereum is unlikely to replace Bitcoin when it comes to being used as a medium of exchange and a store of value.
These two blockchains are the market leaders in what they do, and don't really directly compete with each other.  If a new chain wants to unseat one of them, they would have to be a clear and significant advantage over the current market leader.  So far, that hasn't happened.


Tomatoes...what is the difference between early blight and late blight?

Question: What are the differences in early and late blight of tomatoes?  Can you cut off affected areas of one or both to prolong the life of the plant? What can one do to prevent this disease, what can one do to stop the infection, what can one do to prevent the disease the next season?
Comment: Here is some [very useful information about controlling early blight](http://gardening.stackexchange.com/a/13561/3535).
Comment: This question is rather broad. I'll see what I can do answerwise.
Comment: @ckuhn203 stormy has already seen that one I'm pretty sure, from looking at close reviews.
Answer: Here's the biggest difference: Late blight is caused by the pathogen Phytophthora infestans, while early blight is caused by Alternaria solani.
Phytophthora infestans is an oomycete, a fungus-like eukaryotic microorganism. It is similar to Alternaria solani (a fungus) in that it is a localized disease, and doesn't spread internally. P. infestans is a more aggressive disease, and spreads much faster than A. solani. It also kills all infected material, causing dark, watery spots to form. these eventually become hard and brown.
Control of P. infestans is very difficult. There is no cure for badly infected plants.

If you notice signs of infection, remove all affected parts and destroy them.
If the disease spreads anyway, destroy the entire plant.

You can prevent it to some extent by:

Rotating your crops every year, remembering that both tomatoes and potatoes are susceptible to P. infestans.
Destroying all affected crops as soon as possible. Remove them from the site, and burn them, or place in air-tight bags and send to the landfill. Do not compost.
Growing resistant varieties like 'Defiant', 'Plum Regal', 'Mountain Magic 'and 'Mountain Merit'

Control of A. solani is easier, but it's best to prevent the disease, or catch it early. From: Sudden Outbreak of Yellow Leaves on Tomato (and Other) Plants:

Remove all leaves showing signs of early blight (yellowing, dry margin, large to small round dead spots.)
Do not touch the unaffected leaves with the removed portions, or your hands until they are thoroughly washed.
Spray with a copper fungicide (like BONIDE© Liquid Copper Fungicide). Apply once every 5 days, and after any rain. Continue for 3-4 weeks, or until the plant stops developing the symptoms.

To prevent future attacks, you can try to:

Minimize soil-foliage contact
Make sure the plants get good air circulation (including proper spacing)
When you water, try not to wet the foliage, or splash soil onto the leaf undersides. The fungus spreads faster in wet conditions.
To go along with that, an organic mulch will help keep soil from splashing, and is also useful for many other reasons.
Make sure the plants have a support to climb on.
Rotate the plantings each year, to stop pathogens from inhabiting the soil. Remember that potatoes are also vulnerable to early blight, so plan accordingly.
Comment: Perfect answer! There's something I wanted to add but, can't think right now! Horses rampaging....
Comment: @stormy curious... what were you going to add?
Comment: I will add that the best protection I have found for my plants it to use mulch to prevent splashing of dirt up onto the lower leaves.  I just use grass clippings and make sure to keep up on it; adding thin layers on top of each other week after week.


Prove that for any $a$ and $n > 2$, the last two digits of $a^n$ can not be $30$

Question: I'm confused on how to prove this. I know if I test it out with small numbers it doesn't end up with the last two digits to being 30. But how about larger numbers with larger exponents? Can someone show me how to prove this?
Answer: If the last two digits of $a^n$ were $30$, then $a^n$ would be divisible by $10$.
But then $a$ would be divisible by $10$.
But then $a^n$ for $n\ge2$ would be divisible by $100$, so the last two digits of $a^n$ would be $00$.
Comment: prime factorization:  $10=2\times5$
Answer: If you talk about $a^n$, it is indeed true. You have $30 = 2 * 3 * 5$. Let $a = 2^\alpha q$ where $q$ is relatively prime to $2$. Then $a^n = 2^{n\alpha} q^n$. So for all $k\in \mathbb{Z}$, $a^n + 100k$ will be prime to $2$ if $\alpha = 0$ and divisible by $4$ if $\alpha > 0$. So $a^n + 100k$ cannot equal $30$, and the two last digits of $a^n$ cannot be $30$. You only need $n \geq 2$.


Does qualified immunity protect p. officers from civil liability if found to have abetted conspiracy or maliciously falsified a criminal report?

Question: Is there any cases that decided this question? Can the DA be sued if they know or should know and maliciously prosecute regardless in such a case?
Primarily interested in the State of California.
Answer: To prevail in a lawsuit form money damages against a law enforcement officer who is entitled to qualified immunity one must show an intentional violation of a well established constitutional right that caused particularized harm to the person bringing the lawsuit by a particular law enforcement officer, and must show this by a preponderance of the evidence at trial.
To get to trial in the fact of a qualified immunity defense asserted by the law enforcement officer in a pre-trial motion for summary judgment, you must have evidence sufficient to survive a motion for summary judgment (i.e. evidence that would be admissible at trial in the form of statements made under oath by someone with personal knowledge of the facts asserted, or authenticating otherwise admissible documentary evidence). If the law enforcement officers losers the motion for summary judgment, the law enforcement officer can filed an interlocutory appeal before the case goes forward, to review that decision on the merits.
A well established constitutional right is one arising under the U.S. Constitution (rather than a state or federal statute or common law case or ethics rule, for example) that has been applied in a published opinion constituting a binding appellate court precedent in the place where the misconduct allegedly occurred that is sufficiently factually similar to leave no real doubt that it applies to this case.
There is a well established constitutional right for law enforcement to not knowingly use intentionally fabricated evidence to prosecute you in a criminal prosecution.
But choosing to believe one witness (who the plaintiff in the lawsuit may know is lying, but the police do not definitively know is lying) and not another witness (such as the plaintiff in the lawsuit), or making an inaccurate statement in an affidavit in a criminal case, is not itself sufficient to establish a violation of a constitutional right, without the requisite intent to take actions that violate a constitutional right (e.g. without knowledge that the evidence is false).
A district attorney is not a law enforcement officer in most circumstances, and is entitled to absolute immunity from civil liability when acting to carry out the court process in a criminal prosecution. In these circumstances, you can't sue the DA no matter how intentionally malicious the DA may be in the case.
But, when a district attorney is merely acting in an investigative capacity in a pre-prosecution phase of a criminal case, the district attorney is only entitled to qualified immunity.
You generally cannot bring a civil rights lawsuit for money damages against a district attorney for filing groundless criminal charges against you, although under some circumstances, the court, or attorney regulatory officials could sanction a district attorney for such conduct. Likewise, you cannot sue the DA for cooperating with law enforcement officers who have violated your civil rights in an actionable manner in connection with the court process to prosecute an alleged crime on a conspiracy theory.
Governmental employers are not vicariously liable under the principle of respondeat superior for constitutional right violations of their employees and agents. For the governmental entity to have liability it must be shown to have had a policy (formally adopted or de facto) that violated a constitutional right (and the doctrine of qualified immunity does not apply to this inquiry).
Your description of the nature of the alleged misconduct, which is that a police officer is

found to have abetted conspiracy or maliciously falsified a criminal
report

is far too vague to determine whether or not a cause of action for violation of one's civil rights arises. It also isn't entirely clear if the question about the police officer in the title and the question about the DA in the body are separate questions, or if the question is assuming (usually incorrectly) that the DA is a law enforcement officer.
Like most things in American law, the inquiry is a fact rich and detail specific inquiry.
It could be that there are some state law legal theories for which the State of California has authorized lawsuits for money damages other than a 42 U.S.C. § 1983 action asserting a violation of the U.S. Constitution, under which you could bring claims in California under state law. None come to mind, but I'm not a California lawyer. Usually, intentional tort claims against governmental entities and governmental employees are barred by sovereign immunity.
Comment: thank you! I did not consider the DA a member of the law enforcement, but I did consider it a body that may actively engage in malicious prosecution. In the question case, in that it knows about the abetting of a conspiracy by the police and/or the malicious falsification of a police report, and it regardless proceeds in prosecution. I am finding that the Supreme Court of Canada set case law and since has been allowing for malicious prosecution suits against a DA, sad it's not the case in the U.S..
Answer: I do not find any cases that closely match the descriptions in the question, that police officers have

abetted [a] conspiracy or maliciously falsified a criminal report.

Under current law qualified immunity (QI) protects against suits under 42 U.S. Code § 1983 (Civil action for deprivation of rights) often known just as "Section 1982. It provides that:

Every person who, under color of any statute, ordinance, regulation, custom, or usage, of any State or Territory or the District of Columbia, subjects, or causes to be subjected, any citizen of the United States or other person within the jurisdiction thereof to the deprivation of any rights, privileges, or immunities secured by the Constitution and laws, shall be liable to the party injured in an action at law, suit in equity, or other proper proceeding for redress, ...

Note that "qualified immunity" is nowhere mentioned in this section. It is a purely court-made doctrine, and the courts have not defined it as thoroughly as one might wish. Also, it has been significantly changed over the course of its life.
A key aspect to qualified immunity is that it prevents suits against government officials unless they violate rights that are "clearly established".  This has come to mean that unless there is previous case law with a very similar fact pattern, any suit for damages will be barred. Note that suits against police departments and governments, and suits for injunctions are not affected by QI. Nor are criminal prosecutions of officers or other officials.  Nor are suits under state laws.
Originally defendants had to establish a reasonable, good faith belief that their conduct did not violate the plaintiff's rights, but that aspect was dropped in Harlow v. Fitzgerald, 457 U.S. 800 (1982). Since Harlow defendants need merely show that no right was violated, or that any right violated was not "clearly established", to be protected not just from liability, but from suit, including discovery.
The Cornell LII page on Qualified Imminity lists several significant  cases:

In Harlow v. Fitzgerald, 457 U.S. 800 (1982), the Supreme Court held that federal government officials are entitled to qualified immunity. The Court reasoned that "the need to protect officials who are required to exercise discretion and the related public interest in encouraging the vigorous exercise of official authority." ...

In Malley v. Briggs, 457 U.S. 335 (1986), the Supreme Court examined immunity for police officers with regard to acting on the basis of a faulty warrant. The Court held that qualified immunity does not apply to a police officer when the officer wrongfully arrests someone on the basis of a warrant, if the officer who could not reasonably believe that there was probable cause for the warrant. Reasonability is determined by the action that an objectively reasonable officer would take.

In Anderson v. Creighton, 483 U.S. 635 (1987), the Supreme Court held that when an officer of the law (in this case, an FBI officer) conducts a search which violates the Fourth Amendment, that officer is entitled to qualified immunity if the officer proves that a reasonable officer could have believed that the search constitutionally complied with the Fourth Amendment. The relevant question that a court should ask is whether a reasonable officer could have believed the warrantless search to be lawful, considering clearly established law and the information which the officer possessed. The Supreme Court also held that "subjective beliefs about the search are irrelevant."

In Saucier v. Katz, 533 U.S. 194 (2001), the Supreme Court held that a ruling on a qualified immunity defense must be made early in the trial court's proceeding, because qualified immunity is a defense to stand trial, not merely a defense from liability. When there is a summary judgment motion for qualified immunity, the court should rule on the motion, even if a material issue of fact remains on the underlying claim.

In Safford Unified School Dist. #1 v. Redding, 129 S.Ct. 2633 (2009), the Supreme Court held that even when an individual's Fourth Amendment right to be safe from unreasonable search and seizure is violated, the person performing the search may still be immune under qualified immunity, if "clearly established law does not show that the search violated the Fourth Amendment." However, this holding was in the context of a school official conducting a search of a student for illicit items.

A Washington Post story: "Five myths about qualified immunity" mentions several cases including saying;

For example, the Supreme Court threw out a case last year in which a man sought damages after an officer ordered a police dog to attack him, even though he had surrendered and was seated with his arms in the air. The plaintiff in the case, Baxter v. Bracey (2020), was unable to point to a prior case with similar facts.

Jay Schweikert in the blog post "Blatant Misrepresentations of Qualified Immunity by Law Enforcement" cites several cases including Mullenix v. Luna, 577 U.S. 7, 11 (2015) which make it clear that QI does not apply to criminal proceedings.
The post goes on to say:

[T]he doctrine [of QI] only does work in the space where a constitutional right has been violated, but a court determines this right was not "clearly established" (which generally requires a prior case with functionally identical facts). See Pearson v. Callahan, 555 U.S. 223, 232 (2009) (describing the "two-step sequence" where a court must first decide whether the facts alleged "make out a violation of a constitutional right," and if so, then decide "whether the right at issue was 'clearly established' at the time of defendant's alleged misconduct").
...
in a Sixth Circuit decision called Latits v. Phillips, the court granted immunity to a police officer who ran a suspect off the road with his car, then ran up to the driver's window and shot him three times, killing him. The court first held that this officer did, in fact, violate Mr. Latits' Fourth Amendment rights, noting in particular that

although police procedures do not set the bounds of the Fourth Amendment, we consider it relevant that Officer Phillips repeatedly violated police procedures in both ramming Latits and running up to his car.

Nevertheless, the court still granted immunity to Phillips, because previous Sixth Circuit cases "did not involve many of the key[] facts in this case, such as car chases on open roads and collisions between the suspect and police cars." In other words, the fact that Phillips was violating department policy was irrelevant to the qualified immunity question; all that mattered is that the specific facts of this case were somewhat different from the facts of prior cases.
... For example, in Jessop v. City of Fresno, the Ninth Circuit granted immunity to police officers alleged to have stolen over $225,000 in cash and rare coins while executing a search warrant.

In "Overcoming Qualified Immunity in Civil Rights Claims" the Shouse California Law Group writes:

California law largely follows federal law for qualified immunity (discussed above). But arguably there is no qualified immunity for California police officers accused of false arrest or imprisonment.18 And unlike federal law, California law places the burden on police to justify a false arrest or imprisonment.19
When California law enforcement officers get sued for misconduct, they can ask their police department to defend them going forward. Whether the case settles or the police officer is found liable at trial, the police department is responsible for paying all compensatory damages to the plaintiff. This includes expenses for medical bills, lost wages, pain and suffering, and other out-of-pocket expenses.
How Qualified Immunity Fails by JOANNA C . SCHWARTZ from the Yale Law Journal is a 75-page l;aw review article on the current state of QI and proposals for change. It presents results of a study of over 1,000 cases, showing that claims of QI resulted in dismissal of only 3.9% of the cases where it could hav been raised.

Conclusion
I cannot provide specific cases that address the issues describes in the question. But based on cses where QI has been applied, it might apply in such cases, depending on the specific details, and previous cases found by plaintiffs. However, state-level suits, particularly in California, follow different rules where QI may not apply.
Comment: *Harlow v. Fitzgerald* has joined *Wickard* and *Kelo* in the list of worst SCOTUS decisions that are still in effect.


Why is data augmentation classified as a type of regularization?

Question: In deep learning papers, data augmentation is often presented as a type of regularization. For example, this is explored in Chiyan Zhang and coauthor's presentation at ICLR17, Understanding deep learning requires rethinking generalization. Why is this classification given? Intuitively, I see data augmentation as a way of expanding a dataset, but regularization as a means of modifying a training algorithm to (hopefully) improve the generalization error.
Comment: Could you point us to an article/link stating this?
Answer: Regularization (traditionally in the context of shrinkage) adds prior knowledge to a model; a prior, literally, is specified for the parameters.  Augmentation is also a form of adding prior knowledge to a model; e.g. images are rotated, which you know does not change the class label.  Increasing training data (as with augmentation) decreases a model's variance. Regularization also decreases a model's variance.  They do so in different ways, but ultimately both decrease regularization error.
Section 5.2.2 of Goodfellow et al's Deep Learning proposes a much broader definition:

Regularization is any modification we make to a learning algorithm that
is intended to reduce its generalization error but not its training
error.

There is a tendency to asssociate regularization with shrinkage because of the term "l-p norm regularization"...perhaps "augmentation regularization" is equally valid, although it doesn't roll off the tongue.
Comment: Yes, agreed.  Augmentation really is a way to modify the model, however, to reduce variance, not a step to transform the data such that it is appropriate for learning, which is "preprocessing."
Comment: Thanks, this is actually a good intuitive explanation. With regards to your citation, my main misunderstanding comes from: "... modifications to a learning *algorithm* ...". I suppose I see data augmentation as a preprocessing step, separate to the learning algorithm
Answer: User99889 had a good answer (+1), I will add some comments to elaborate the points.
The goal of regularization is reducing the Variance and increase Bias in Bias Variance Trade Off. This can be achieved in different ways, here are some examples:

Increase the amount of the data, collect new data or derive new data from existing data / data augmentation.
Reduce the complex of the model. For example, reduce the hidden layers or number of units in the hidden layer.
Put constraints in the coefficients/parameters. For example, L1 or L2 regularization.

We will further to explain why User99889 mentioned about "add prior / domain knowledge". Let use MNIST data as an example, we can create more data by using the following knowledge:

If we re-scale digit, the label will not be changed
If we shift digit, the label will not be changed

Then, we have more data using domain knowledge and the model will have more Bias.
Comment: So does this mean, also, that providing more data is a form of regularization? By extension, is using better quality data a form of regularization?
Answer: The objective of regularization is to improve the generalization capability of the model (in other words its ability to perform well on unseen data).
Regularization can be explicit or implicit. The first case refers to techniques that can constrain the effective capacity of the model in order to
reduce overfitting. Examples include adding a penalty term in standard statistical estimators such as OLS or weight decay and dropout in deep learning.
In the second case (implicit regularization) instead of explicitly constraining the capacity of the model we use indirect methods. One example,
is using SGD to train linear models as it always converges to a solution with a small norm (https://arxiv.org/pdf/1611.03530.pdf).
Similarly, data augmentation (which has many forms e.g. adding predictors, adding artificially created data, resampling) will help the model to generalize better
and is thus considered to be an implicit regularization method.


Are Christian Scientists against the regulation of antibiotics in agriculture?

Question: Governments around the world are heavily regulating the use of antibiotics in agriculture in an attempt to curb superbacteria. But Christian Scientists believe, as far as I understand it, that antibiotics do not really help because all diseases are psychosomatic. So, are they against such regulation? Do they believe that the egg industry should be allowed to use as much antibiotics as it wants to?
Comment: I agree that their theology is unique but just because a group of people self-identify as being Christian does not necessarily mean they are Christians. I hope to look into this tomorrow in order to find an answer your question.
Comment: I have been unable to find any official Christian Science references specifically about the egg industry and the use of antibiotics or generally to do with agriculture and the use of antibiotics. What, might I ask, does this have to do with Christianity?
Comment: @Lesley Well, Christian Science is a branch of Christianity, isn't it? It just has a unique theology.
Answer: It may well be that Christian Scientists don't believe that antibiotics can help to curb disease, but that may not have any bearing on whether they are against government regulation of antibiotics.  Here, in Europe, regulation has worked positively to reduce the use of antibiotics in poultry farming.
My search on official Christian Science web sites failed to find anything about the use of antibiotics in general or in chicken husbandry in particular.  However, I did find an old (1907) article on weeds: an article

WEEDS: As the serious prevalence of weeds is an infallible indication of poor farming, so the abundance of undesirable thoughts is a never-failing sign of poor thinking; and conversely, the absence is a sure concomitant of good thinking.  No student of agriculture denies that scientific methods are needed to obtain the best results in farming, and it is [of] infinitely greater importance to understand and practise the Science of Mind in order to get rid of the evils which for so long a time have been permitted to grow in human consciousness.

The Christian Science Monitor December 2023 issue had this article about a new generation of young farmers who are finding success with small agricultural projects that result in a more sustainable lifestyle:

"There's been a really kind of dramatic change in the way that farmers see what agriculture can do," says Jules Pretty, professor of environment and society at the University of Essex in England. .. But the thing about regenerative practices – farming that rebuilds ecological health even as it harvests – is that they're nearly impossible to do at a large scale. Industrial agriculture is built to go big. That means long rows of single crops that allow for high-tech automation and big farm equipment, chemical inputs like pesticides and synthetic fertilizers that increase yields, and economies of scale that keep prices low. .. Regenerative agriculture, on the other hand, attempts to rebuild ecosystems in a way that integrates the various plants, animals, and microbes that naturally exist in a specific place.

With regard to what's going on in the U.S. with the regulation of antibiotics in poultry farming, this article says:

In recent times, antibiotic use in poultry production has become a subject of debate because of concerns about bacterial antibiotic resistance.

It is noteworthy that antibiotics can migrate into and accumulate in the egg of the chicken being treated.  Antibiotics are also fed to cattle.  Regulation that results in controlling the use of additives (such as pesticides and antibiotics) must be a good thing.
Conclusion: I can only assume that Christian Scientists will continue to use natural and non-invasive farming techniques whether in agriculture or in poultry farming.
Answer: Antibiotics themselves aren't connected with any Christian prohibition (unlike blood for example), but too big usage of them may hurt peoples' health. In this way we are for reducing antibiotics.
Comment: Hello! The question is asking for answers from the perspective of the Church of Christ, Scientist (https://en.wikipedia.org/wiki/Church_of_Christ,_Scientist), also known as Christian Science, while your answer appears to be from a general Christian perspective. Do you have a source specifically for what Christian Science teaches on this issue?


Get custom options from nominal items that were ordered

Question: In a helper class, I am trying to get, via a foreach loop, custom options from each purchased product from a loaded order. I am successful in grabbing the options and option values on each regular virtual product. However, when it comes to nominal virtual products (recurring based), the below code won't pick those picked options up from the order.
Since $item->getProductOptions() is null on nominal virtual based products, is there another way I can get what options the customer picked? Note that customers are able to pick the custom options before placing any products (including nominal) into the cart and checkout successfully.
The below code is successful in getting custom options on virtual products, but not with nominal virtual products:
$items = Mage::getModel('sales/order')->loadByIncrementId($orderId)->getAllVisibleItems();

$productOptions = array();
foreach($items as $iKey => $item) {
    $options = $item->getProductOptions(); /* Null on nominal products only */

    foreach($options['options'] as $oKey => $option) {
        $productOptions[$iKey]->label = $option['label'];
        $productOptions[$iKey]->id = $option['option_id'];
        $productOptions[$iKey]->type = $option['option_type'];
        $productOptions[$iKey]->print_values = explode(",",$option['print_value']);
        $productOptions[$iKey]->option_values = explode(",",$option['option_value']);
    }
}

*Note that I am still able to get all items, just not their options in nominal based products.
Update:  I've looked at the DB table sales_flat_order_item and found that the column product_options is null on nominal products but has listed options for regular products. Since Magento's recurring feature is listed as (beta) that this maybe a bug.
Answer: Have you tried to list the contents of the order_item_info from Magento's sales_recurring_profile table?
I'm using Mageworx Advanced Product Options, and Recurring Virtual Products with Custom Options get that Custom Option data dumped into that cell.


Buy 3 items and get the cheapest one free: Magento 2

Question: I'm searching for at solution for being able to sell a customer 3 different product items and then getting the cheapest one for free.   Can I accomplish this through the magento admin or does it require custom coding/extension?   I'm on Magento ver. 2.1.7.
Answer: Unfortunately this would require custom coding or an extension. There is no way to do this in default Magento.
Comment: Any idea who makes an extension that does this or how long it takes to write custom coding for this?
Comment: I haven't used it but I have heard good things about Amasty Special Promotions. I would chat in with them and ask if it can do that.
Comment: Thanks, it looks form their product listing page: https://amasty.com/special-promotions-for-magento-2.html that it does exactly what I want.


Disable iMessage in MFMessageComposeViewController

Question: I'm developing an iPhone app that requires MFMessageComposeViewController to send texts as actual texts and not as iMessage. Is there a way to protect the texts from being sent as iMessage?
Comment: Out of curiosity, why?  Why would you try and break my messaging experience?  If I don't have a SMS plan on my phone, this requirement would *cost me money*.
Comment: @DaveDeLong: But it is possible users are aware of costing before sending. Message sending will be failed if iMessage not available on the other hand. Implementing `MFMessageComposeViewController`in app will not serve purpose as user will only come to know failed message delivery when he/she goes to messages and notices otherwise they will be under impression that SMS is delivered (let's assume they really want to send SMS.)
Comment: The app is about text-messaging. Mainly delivery reporting. You don't need delivery reporting for iMessage, as it's already developed by Apple.
Answer: No. iOS controls the routing and there's no way to impact it. (Even from Messages you can't control this.)
Comment: Thanks! Then I have to write a note to the users, not to use iMessage :-)
Comment: Is it then posible to receive a message from MFMessageComposeViewController, if the iMessage was delivered correctly?
Comment: I'm pretty sure not. You can check if it's possible to send texts, but you can't tell if they were sent or not (because the phone was unable to send them or because the user canceled.) I believe Apple would consider this a privacy issues. There are alternative ways to send texts via web services, etc., but that's a whole different kettle of fish.


Openshift not displaying application at given URL

Question: I've been trying to deploy my own application up to openshift, and I followed the instructions and have started the Tomcat 7 instance, MySql cartridge and all seems to be running.
When I hit the site url, it shows the default openshift information page, my application is written using JSP/Servlet, mySQL.
On pushing the code to git, as far as I can tell the push went ok. See attached output.
I have an index.jsp in my application, and have set a welcome file mapping to urlPattern /home, as shown in the web.xml below.
<?xml version="1.0" encoding="UTF-8"?>
<web-app
        xmlns="http://java.sun.com/xml/ns/javaee"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
  http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0">
    <welcome-file-list>
        <welcome-file>post/index.jsp</welcome-file>
    </welcome-file-list>

The push to openshift/git:
remote: [INFO] BUILD SUCCESS
remote: [INFO] ------------------------------------------------------------------------
remote: [INFO] Total time: 52.392s
remote: [INFO] Finished at: Fri Apr 18 14:36:05 EDT 2014
remote: [INFO] Final Memory: 8M/77M
remote: [INFO] ------------------------------------------------------------------------
remote: Preparing build for deployment
remote: Deployment id is 527129b9
remote: Activating deployment
remote: + tmp=/var/lib/openshift/53516eaa4382ec7e990002c3/jbossews//tmp
remote: + '[' -d /var/lib/openshift/53516eaa4382ec7e990002c3/jbossews//tmp ']'
remote: + for d in '$tmp/*'
remote: + '[' -d '/var/lib/openshift/53516eaa4382ec7e990002c3/jbossews//tmp/*' ']'
remote: + '[' -d /var/lib/openshift/53516eaa4382ec7e990002c3/jbossews//work/ ']'
remote: + rm -rf /var/lib/openshift/53516eaa4382ec7e990002c3/jbossews//work/
remote: ++ ls /var/lib/openshift/53516eaa4382ec7e990002c3/app-root/runtime/repo//webapps
remote: + '[' ROOT.war ']'
remote: + rsync -r --delete /var/lib/openshift/53516eaa4382ec7e990002c3/app-root/runtime/repo//webapps/ /var/lib/opensh
ft/53516eaa4382ec7e990002c3/jbossews//webapps/
remote: Starting jbossews cartridge
remote: Found 127.6.235.1:8080 listening port
remote: -------------------------
remote: Git Post-Receive Result: success
remote: Activation status: success
remote: Deployment completed with status: success

Any help greatly appreciated. Sorry for the newbie approach, but its my 1st time :)
Answer: Following is the approach i would take to troubleshoot. Since you didn't mention the exact error message, I would refer to generic troubleshooting. This can be used for any "route not working" problem
The Communication flow is
Browser > Route > service > pod
Stand up another pod which curl installed.
First curl to pod IP address (You can get pod if from pod description or oc get pod -o wide )
If it works as expected, move to next layer that is service
curl to the service ip or hostname (oc get svc , the Cluster-ip is of our interest here)
If this works, then you can try reaching out to the route url.
This way you can determine where exactly it is breaking


Is it possible to explain why Lasso models eliminated certain coefficient?

Question: Is it possible to understand why Lasso models eliminated specific coefficients?. During the modelling, many of the highly correlated features in data is being eliminated by Lasso regression. Is it possible why precisely these features are being eliminated from the model? (Is it the presence of any other features/multicollinearity etc.?
I want to explain the lasso model behaviour.
Your help is highly appreciated.
Answer: Have a look at "Introduction to Statistical Learning" (Chapter 6.2.2). The Lasso adds an aditional penalty term to the original OLS penalty. In addition to the residual sum of squares (RSS, which is minimized in OLS),  there is an additional term, the shrinkage penalty. Basically, coefficients which do not contribute much to a "good fit" are shrunken. Actually there is a set of $\beta_j$ for each $\lambda$ (the tuning parameter).
Not knowing your data, I can only guess that many of your highly correlated features "do not contribute much" to a "good fit" in your model. This may be a consequence from multicollinearity. However, the Lasso does not per se "shrink" features with high correlation. It rather looks for a subset of coefficients $\beta$ which produce a "good fit".
You may check whether multicollinearity is a severe issue in your data, e.g. by looking at the Variance Inflation Factor (VIF) and remove possible features with (very) high correlation.
Comment: Thanks, @Peter. How come highly correlated features "do not contribute much" to a "good fit" in your model?.
Comment: Hard to tell not knowing the data. May be that they do not predict well in the first place. May also be that the model is "spoofed" by correlation. That's why I suggested to use VIF and remove "redundant" features so to get rid of multicollinearity.


How to go about contacting an author regarding questions on their research?

Question: There is a scientist I am interested in contacting with expertise in peptidomics. I would like to email them to ask if they had ever explored findings from a related area of research. How do I politely contact them for their input?
Answer: Send them a brief, polite email. Brief because nobody has time to read huge walls of text from strangers; polite because you want them to help you.
Answer: First of all, check their personal website and any other content they have published which you have access to which may already offer the input you require. It would certainly be in order to personally e-mail the researcher, but be specific as to the type of input or information you require. The scientist is probably very busy, and a broad question is more likely to go unanswered in that case.
If you intend to refer to certain findings from a related field, ensure you provide all the necessary information to answer your question, or at the very least provide links to the related papers or websites for the convenience of the researcher.
Answer: Virtually every publication will list a corresponding author along with contact information, usually an email address and/or phone number. All authors are listed with their university and department.  You can and should use any or all of this information to find these people and get in touch with the authors of any papers about which you have questions.


ANN produces different result every time it's run

Question: I tried an artificial neural network (ANN) model. Using same data set, it gives a different answer every time I run it in MATLAB. Does anyone why this happens and can suggested the best way to analyze the result?
Answer: Different model runs producing different outcomes is a common outcome with ANNs. The response surface over which the minimization takes places is nonconvex and many (all?) ANN estimation methods are sensitive to the starting point of the optimizer, among other inputs.
People who are new to neural networks are often surprised by non-determinism, since it stands in contrast to strongly convex optimization problems like OLS or logistic regression, where global minima can reliably be found (so long a certain regularity conditions are met).
To fix in your mind how this works, consider some random initialization $x^{(0)}$. You supply a mini-batch to the neural network and compute the gradient and apply the update, so now you have $x^{(1)} = x^{(0)} - \eta \nabla f(x^{(0)})$ where $\eta$ is the step size.
Now you start over and make a new random initialization $\tilde{x}^{(0)} \neq x^{(0)}$. Now the gradient update is given by $\tilde{x}^{(1)} = \tilde{x}^{(0)} - \eta \nabla f(\tilde{x}^{(0)})$. In general, we will have $\tilde{x}^{(1)} \neq x^{(1)}$: we started at a different spot on the optimization surface each time, and also we  used stochastic gradient descent to take a step in the direction of the expected gradient, where the expectation is estimated using a small sample of the training data. Each of these conditions implies that we are likely to end up at a different location: we started in 2 different places ($x^{(0)}$ or $\tilde{x}^{(0)}$), and we moved in 2 different directions (the value of $\nabla f$ is different).
You could fix the model to start optimization at a particular point, which would remove one source of randomness, but perhaps not all sources of randomness (such as SGD, or dropout, or the random sampling step in a variational auto-encoder). Fixing the random seed  should make the results reproducible in all places that seed is used. Depending on the software, use of third party libraries or similar corner-cases could mean that you have to set the random seed  separately for each software component.
Comment: IF doing this the ANN output result will be consistent?
Comment: @bbadyalina Not necessarily. To produce a consistent output, you would have to fix every random component of the model estimation, and it is not clear that the only random component of the model that you are estimating is initialization. The last paragraph provides an example of a second source of randomness: mini-batching.


How to delete books from iBooks on iOS 10?

Question: I want to delete some iBooks from purchased off my iBooks app, but the previous solution of hovering above it and an "x" appearing over it isn't working. I have an iPhone 7 with iOS 10.3.2
Answer: To delete books in the iOS 10 iBooks app:

Tap "Select" in the top right.
Tap on the books you wish to delete (in the list view, you can also tap the checkboxes).
Tap the "Delete" button in the top left.

You can re-download deleted books from the "Purchased" tab.
Answer: If I open iBooks on my iPhone I can get a listing of my books. At the top of page there is a 'select' button. If I select a book, the top menu changes to 'view move delete'. The delete option will remove the book.


What variety of plum tree do I have?

Question: I bought house in central Oklahoma 4 years ago. It has a plum tree that sits alone in front yard. 2 years ago it produced the best plums I've ever had but none since. I've tried to find out why which brings me here, as I'm hoping to get help identifying it. It's approx 15 feet tall with green leaves, brownish red bark that's got spots and vein-like lines. The leaf stalk is light green. Also the leaves are simple, ovate, with toothed margins not overly sharp.
Comment: Please add a photograph of the tree and some close-ups of the leaves, flowers, bark, etc.
Comment: Because many plum cultivars are very similar in appearance, it would help a lot for you to describe the fruit (color, size, firmness, sweetness, etc.).
Comment: Is it flowering and just failing to produce fruit, or is it not even flowering? Some plums are a little temperamental, like the green gage, and won't produce every year. It'd be hard to know if that is the issue, though, without seeing the fruit.
Answer: You said your tree is in your front yard. Is it near or in a lawn? It might be that you've been fertilizing your tree with lawn fertilizer. The high nitrogen for lawns might be suppressing reproductive growth.
Two years ago you had plums. What happened last year? Have you done extensive pruning, fertilized or sprayed with anything...?
Identifying a plum and its variety will be tough. We need to have pictures of buds, leaves, and bark, but mainly the flowers and fruit. Do any of your neighbors have the same tree?

What variety of plum tree do I have?


The viability of frontline infantry mechs

Question: The mechs that have been developed are 40 tons and 5 meters tall at the smallest and can reach to 250 tons and 25 meters tall at the biggest. They are mostly capable of carrying large weapon systems and are somewhat manuverable, depending on the chassis and the skill of the pilot. Would they be able to replace the traditional frontline infantry soldier in all the duties that they carry out? This includes fighting against opposing forces of a similar tech level as well as fighting smaller fighting forces. If not, what sort of roles could the mechs never fill and what would they best be suited to?
Comment: Your mechs are clearly useless inside buildings, due to size and mass. They also have very limited abilities in cities, for the same reasons. They will alos severely damage or destroy any road they might be operating on. And they are at best as useful as a conventioneal tank on soft terrain. Also, their high center of gravity should make them prone to fall over. So, in general: they might be frightening, but don't sound like a good idea.
Comment: And http://worldbuilding.stackexchange.com/questions/9423/towering-titans-of-technological-terror
Comment: @TimB I can see the similarities between the questions, but I just wanted to know whether these established mechs would be useful as frontilne infantry roles. The other questions seem to be based around the general usage of mechs in combat roles.
Answer: Infantry and armor are separate divisions for a reason. A tank or a mech would never be able to effectively capture an objective unless it is sitting in the middle of a plain with strong surface. In cities, forests, deserts, shores, etc. the mobility provided by infantry cannot be replaced by the size, armor and firepower of mechs. Current trends in warfare eschew frontal conflicts in favor of asymmetrical warfare (Middle-East) and covert operations (Ukraine), in these situations mechs would mostly just be dead weight.
They could however serve as mobile HQs, carrying supplies, officers, comm gear and other stuff that is good to have sometimes. This way the reduced speed (compared to wheeled, tracked or flying units) and the reduced mobility (compared to infantry) does not pose a problem, and the heavy firepower could come handy in case of an assault. The huge carrying capacity (What else would fill 250 tons, if the Battletech mechs max out at 135, and even they can lay waste to entire cities? Certainly no more weapons are required.) could be useful for repair facilities, medical bays, etc.
This proposition would essentially turn mechs into walking bases, and in this view it would make sense to have a mobile (transport) and a stationary configuration, with the former offering the legs less protection but more mobility, and the latter anchoring the mech to the ground, sliding armor plates over the vulnerable leg joints and extending the big guns and sensors on arms, therefore making aiming and target acquisition easier. For references see the Transformers Trypticon and Metroplex, both have an "assault base" configuration.


How can i show all edges in monogame?

Question: I am using Monogame 3.5 and i have simple model of cube. I use BasicEffect to draw it. I want it transparent so i use effect.Alpha = 0.5f. Is it possible to show all edges something like on picture?
Answer: Perhaps you could change the RasterizerState fill mode.
RasterizerState rasterizerState = new RasterizerState();
rasterizerState.FillMode = FillMode.WireFrame;
GraphicsDevice.RasterizerState = rasterizerState;

How can i show all edges in monogame?


What is the correct way to write "To all who handles" or "To all whom handles"?

Question: What is the correct way to write "To all who handles" or "To all whom handles" or "To all who is handling" ?
Comment: Please show the complete sentence.
Comment: None of the options you give is correct: _all_ is plural and requires that the verb in the following clause be plural too. _To all (those) who handle X_ and _To all (those) who are handling X_ are both grammatically correct, but they would be used in different contexts; so as mplungjan says, please edit your question to indicate in what context the phrase is to be used.
Comment: Simple rule for English learners: Don't use _whom_. Ever. It will take you years to learn how it's sposta be used, and even if you use it correctly, so many English speakers use it incorrectly that they will consider you wrong. There's no way to win.
Comment: ... The bell tolls for 'whom'.
Comment: You need to post a complete sentence. But when in doubt stick with "who". It's better to use "who" and get it wrong than to use "whom" and get it wrong, because the latter is likely to attract more ridicule.
Comment: A handy rule of thumb (I AM joking, of course) is that if you would use the Nominative in Latin, use "who", otherwise use "whom". Please don't use this in real life though, and just use "who", as everyone else has said. :-)
Answer: All are incorrect. As you do not give the context, I will add one.
"Give the warning to all who handle the chemical."
"Give the warning to him who handles the chemical."
"To him who handles the chemical, I would give the following warning…"
"To all who are handling the chemical, I would give the following warning…"
The confusion between "who" and "whom" may be coming from two directions. Following "to," you expect to use "him, us, them, whom," etc. As the subject of the verb "to handle," however, you expect to use "he, we, they, who," etc. It may be helpful to think of "who handles the chemical" as an entity: Someone handles the chemical; it is "he handles," not "him handles."
Answer: "to all who handle" is correct (not one of your choices).
Confusion is:
to all (who handle)
vs.
to whom
"who handle" modifies all. The use of whom is obviated by the use of all. "handle" is the correct form of the verb.
The comments or responses which say to avoid "whom" are really contributing to ignorance rather than insight. Sadly that is common these days.


Does anyone know about how LinkedIn was compromised?

Question: I know some super basic stuff about website security (e.g. using HTTPS, escaping user input), but hearing about high profile sites getting compromised makes me wonder in what way they were broken into, and what I could do to prevent such attacks on my own websites. A few searches on Google didn't turn up anything on how exactly the attacker managed to grab 6.5 million password hashes from LinkedIn, so I wanted to see if anyone here had an idea of what happened that day?
Comment: You can protect your website from SQL injection by using prepared statements (e.g. mysqli::prepare in php) for at least all queries that get user input (or derivates from user input).
If you're not yet using it, check it out, it has more interesting advantages.
Answer: It was almost certainly SQL Injection.  This is really the best tool when it comes to a hacker reading information out of the database.  Its easy to say "oah we sanitize user input",  but it only takes missing quote marks on one variable,  or forgetting a single call an escape routine to leak 6.5 million password hashes.  Parameterized queries (when used properly) effectively stops these common mistakes.
That being said not every password leak is SQL Injection.  The recent IEEE leak was due to an HTTP log file on their FTP server.  Insecure logging or not being careful with a database backup can also lead a huge leak such as this.  As a pentester I see these mistakes all the time.
Comment: Dang cool. First time I learned about parameterized queries. Thanks!
Answer: It was SQL injection, but there are no detailed reports out there. I remember reading something about a LinkedIn Facebook plugin of some sorts which was the entry point. But that was just the breach. If you are looking to learn why the passwords were compromised, it was because of the way LinkedIn stored the passwords. They stored it as an unsalted SHA1 hash, which meant attackers could easily figure out the passwords with rainbow tables.
Comment: Related: [How to securely hash passwords?](http://security.stackexchange.com/questions/211/how-to-securely-hash-passwords?lq=1)


Prove, axiomatically that $1$ does not equal $0$.

Question: I attempted proving this but came across many circular arguments. How would one prove such a claim without circular arguments?
Comment: Using what axioms?
Comment: If $1=0$ and $a$ is any element, then $a=a\cdot 1 = a \cdot 0 =0$ so there's only one element in your set. [Uses some defiinitions from what a unitary ring is, and some consequences of axioms] Note that many collections of ring axioms do not rule out $1=0$ but call such a thing the "zero ring" ...
Comment: Axiom 1. $1\neq0$. Proposition 1. $1\neq0$. *Proof.* From axiom 1, we have that $1\neq0$. $\blacksquare$
Comment: Before we answer the question we need to know what you mean by $0$ and $1$.
Comment: 1 equals 0 in modulo 1 arithmetic (which is trivial). What system are you working in?
Comment: How about proving that $1+1 \ne 1$?
Answer: If you start with Peano axioms for the natural numbers, then $0$ is part of the language, but $1$ is not. We use $1$ as a shorthand for the term $s0$.
Now we can use the axiom $\forall x(sx\neq0)$, and infer that in particular for $x=0$ it is true that $s0\neq0$. Congratulations, we proved that $0\neq1$ axiomatically.
You can choose different contexts, like set theory, field theory, ring theory or other contexts in which we can interpret $0$ and $1$. You can also find contexts in which $0=1$ is a provable statement. For example the theory whose single axiom states $0=1$. True this theory describes very little of what we expect from the natural numbers, or the symbols $0,1$ to mean. But it is a mathematically valid thing to do.
Answer: 1) Prove $a \times 0 = 0$ for all $a$.
$a \times 0 = a(1 - 1) = a - a = 0$.
2)  If $0 = 1$ then $a = a \times 1 = a \times 0 = 0$
So all terms equal 0.
Which isn't actually a contradiction.  It just means we are working with a trivial field.  If the field isn't trivial (say the Reals) than $0 \ne 1$.
Comment: Assuming the axioms are field axioms.
Comment: It is actually the [zero or trivial ring](https://en.wikipedia.org/wiki/Zero_ring).  Good sets field axioms avoid it by explicitly assuming $1 \not=0$ as an axiom.  That then makes an axiomatic proof rather easy
Comment: Yikes.  I said that 2 years ago!  I've seen $0\ne 1$ explicitly omitted from field axiom.  I''m sort of reluctant because defining things by axiom seems weak when we can prove something instead.  And $1=0\implies $ trivial ring seems worth discovering  Still, defining a field from a ring by defining it to have multiplicative identity and non-trivial inverses makes a lot of sense.
Answer: Maybe we have an axiom that says $0$ is the additive identity and another axiom that says $1$ is the multiplicative identity, that is to say, $x + 0 = x$ and $x \times 1 = x$. Then, in order for $0 = 1$, we'd need to have $1 + 1 = 1$ and $0 \times 0 = 0$. But this implies that $1 \times 2 = 1$, contradicting the multiplicative identity axiom which requires $2 \times 1 = 2$. (Maybe we also need an axiom saying addition and multiplication are commutative).
Comment: $1\times 2=1$ only contradicts $2\times1=2$ if $1\ne 2$.
Comment: @RobertSoupe: If $1=2$ then $1\times 2=1$ does not contradict $1\times 2=2$; indeed, you can *derive* $1\times 2=1$ from $1\times 2=2$ and $1=2$ (Just use the [Euclidean relation property](https://en.wikipedia.org/wiki/Euclidean_relation) of equality).
Comment: @celtschk I think I see your point. But at the same time I also feel like maybe this is shifting Neel Shah's question up a notch.
Comment: So maybe I have run into one of the same circularities as Neel...
Comment: If I understand correctly, $1 \times 2 = 1$ contradicts the axiom that $1 \times x = x$. In this case, $x = 2$, so $1 \times 2$ should be 2, not 1.
Answer: This is one of those deceptively simple questions that is actually rather tough. Declaring $1 \neq 0$ seems rather cheap, but I can't think of a better way. In the hopes that it helps someone come to be a better answer, here's my attempt:
If $x = y$, then $x - y = 0$ and $x \div y = 1$. Obviously $1 - 0 = 1$ but that doesn't help us since maybe $1 = 0$. Nor does $0 \div 1 = 0$ help either. However, $1 \div 0$ is normally considered undefined, and attempts to define usually go for infinity.
Of course the big flaw in this whole argument is that $0 \div 0 \neq 1$ unless we explicitly defined it that way for the purpose of proving $0 = 1$.
Answer: Some good ideas so far, but trying to bring in multiplication is problematic. I think you have to focus on addition here.
Axiom $0$. The additive identity is $0$. Thus $n + 0 = n$.
Axiom $1$. The successor interval is $1$. Thus the successor of $n \in \textbf{Z}$ is $n + 1$. If $n'$ is the successor of $n$, then $n < n'$ and $n' > n$.
Axiom $2$. Addition is commutative. Thus $a + b = b + a$.
Therefore, $0' = 1$, because $1 + 0 = 0 + 1 = 1$. This sits well with Axiom $0$ and Axiom $1$.
Maybe $0 = 1$. But by Axiom $1$, we have $1 > 0$ and $0 < 1$, flatly contradicting $0 = 1$. We conclude that $0 \neq 1$ after all.
Comment: Sometimes it's hard to tell the difference between rigor and pettiness. A comment along the lines of "you haven't defined the comparison operators" would lead me to think it was the former rather than the latter.
Comment: This doesn't work - you need some axiom asserting that $a=b$ implies $\neg(a<b)$.
Answer: Proving $0\neq 1$ was shown above (@Asaf Karagila) in the context of a Peano system. If, however, you are trying to prove $0\neq 1$ in the context of the Real number system, the order axioms are required as shown below.
(Note: here the Reals are based directly from the field axioms, order axioms, and the completeness axiom, as opposed to being considered an extension(s) of the Rationals, Integers, or Natural number systems.)
It is sufficient to use the field and order axioms to prove that $0\neq 1$ (so this result also applies in the context of the Rational numbers). The order axioms can be presented as follows:

(O0): There exists a non-empty subset $P$ of $\mathbb{R}$, called the set of "strictly positive real numbers."
(O1): If $a,b\in P$, then $a+b\in P$.
(O2): IF $a,b\in P$, then $a\cdot b\in P$.
(O3) "Trichotomy Property": If $a\in\mathbb{R}$, then exactly one of the following holds: $a\in P,\ a=0,\ -a\in P.$

First, it was shown above (@fleablood) using the field axioms, that if one assumes $0=1$, then the result is a trivial situation in which all elements of $\mathbb{R}$ equal $0$.
However, a contradiction arises in the trivial solution of $a=0$ for all $a\in\mathbb{R}$. This is because Order Axiom (O0) requires $P$ to be non-empty, but if $a=0$ for all Real numbers, then the Trichotomy Property (axiom (O3)) indicates that $-a,a\notin P$ for any $a$. Hence, the assumption that $0=1$ must be false.
Comment: This depends on your axiomatizations. In many places, fields are given a nontriviality axiom, namely $0\neq 1$. So proving $0\neq 1$ there is even shorter than the proof I suggested in PA.
Comment: Alternatively, given the nontriviality axiom, one could weaken the Order Axioms by not requiring $P$ to be non-empty.  Then the property $0\neq 1$ can be used to prove that $P$ is non-empty.
Comment: @AsafKaragila, that is something good to know, as I was not aware of it (the Real Analysis textbook I used in college does not assume a nontiviality axiom).  In any event, the above proof at least shows that the nontriviality axiom is redundant (and therefore consistent) with the field/order axioms.
Answer:
I attempted proving [$1 \neq 0$] but came across many circular arguments. How would one prove such a claim without circular arguments?

Any proof of that is circular in substance.
There is a non-circular proof only in a thin definitional sense particular to a given theory, such as valid derivation from axioms in Peano Arithmetic or Zermelo-Fraenkel set theory.  In almost any other meaningful sense, a proof that $1 \neq 0$ assumes more than its conclusion.  You need a certain minimal amount of mathematics to get an axiomatic proof system up and running, such as the ability to parse strings of characters and tell them apart. Distinguishing $1$ from $0$   is far less than what is needed for that.
A proof of the inequality is also circular in the meta-theoretical sense that the theories accepted as foundational schemes for arithmetic have been pre-selected for their apparent inability to prove $0=1$, as well as their demonstrated ability to prove $0 \neq 1$.  A theory that proves $0=1$ is (for most purposes) deemed to be inconsistent, and one that does not prove $0 \neq 1$ is too weak for serious use.  One is "deriving" 0 < 1 from axioms chosen for their ability to reach that conclusion, and not only their a priori feeling of correctness as a basis for mathematical reasoning.
Answer: Adding on to other answers here. From a Real Number system approach, instead of the ordering property (There exists a non-empty subset  of ℝ, called the set of "strictly positive real numbers."), you can also prove the same progression with "There exists at least 2 distinct real numbers".
This is to say, 1 = 0 iff ∀ℝ = 0. This feels like the weakest axiom possible here, as it makes no claim to order, just being distinct. It also gives more information than just assuming 0≠1.


Kamma vs. kiriya / kriya

Question: What is the difference between the terms kamma and kiriya / kriya?
What is the difference between kiriya and kriya?
Please provide references to kiriya / kriya from the Pali suttas.
Answer: An extended discussion with Bhante Ariyadhammika, former Bhante Varado and Upasaka Sadhamma on the topic might enlighten till release from doubts, if not just after amassing (of course plenty of references incl. anyway): 'The Kamma of Arahants'!!, good householder. It needs care and much attention to get through the net rightly.
Answer: KiriyaCitta is KusalaCitta of Arahanta (Arahants' wholesome-mind) because Arahanta can't do any Karma which effecting next life anymore.

Katamañca    puṇṇa   kammaṃ   akaṇhaṃ   asukkaṃ   akaṇhaasukkavipākaṃ    kammakkhayāya     saṃvattati
What is neither-dark-nor-bright kamma with neither-dark-nor-bright ripening that leads to the exhaustion of kamma?

You should read MN Kukkuravatika Sutta, and AN  Kammavagga in detail.
Also Sankhara is depending on Avijja, and  KammaBhava is depending on Tanha, Arahanta has no Tanha, so his new karma has no  next-life-resultant.

Iti kho udayi tanhakkhaya kammakkhayo kammakkhaya dukkhakkhayoti.
And so, Udāyī, when craving ends, deeds end; when deeds end suffering ends."

According to commentary, Abhidhamma was authored by ven. Sariputta (AggaSavaka), follow to the brief teaching of the Buddha, so it is ven Sariputta's writing style which is proper for the very in detail of Abhidhamma's contents, too deep and too specific for normal word.
Whole Tipitaka come out from 4th Jhana-Mastery's mouth, especially from Arahanta-Jhana-Mastery. Every 4th Jhana-Mastery has photographic memory and super unnatural mind speed.
So, it is normal if the ordinary people can't see the realities arising and vanishing super fast and super small follow Abhidhamma and many Suttas because only very few people can do only  sitting meditation whole days for at least 6 months to 5 years to get 4th Jhana Masery and high level insight meditation.
Answer: AN 3.137 says without any explicit application to Arahants:

Makkhali, that silly man, has this doctrine and view:
Makkhali, bhikkhave, moghapuriso evaṁvādī evaṁdiṭṭhi:
'There is no power in deeds, action, or energy.'
'natthi kammaṁ, natthi kiriyaṁ, natthi vīriyan'ti.

The term 'sacchikiriyāya' (from Sk. sākṣāt kṛ; the P. form being *saccha° sākṣāt (साक्षात्).—prep (S) before, in the presence of, evidently to the sight or sense of. 2 ad Manifestly, obviously, evidently) is found in MN 10, as follows and appears synonymous with sacchikaroti; and also appears to have the sense of 'completion/fulfilment':

to realize extinguishment.
nibbānassa sacchikiriyāya
MN 10

Now, there are gentlemen who, relying on the teaching and training
proclaimed by the Realized One, achieve a high distinction such as the
following: they realize the fruit of stream-entry, the fruit of
once-return, the fruit of non-return, or the fruit of perfection. And
in addition, there are those who ripen the seeds for rebirth in a
heavenly state. The person who spoke like that makes it difficult for
them. They're acting unkindly, their heart is full of hostility, and
they have wrong view.
Evaṁvādī so ye te kulaputtā tathāgatappaveditaṁ dhammavinayaṁ āgamma
evarūpaṁ uḷāraṁ visesaṁ adhigacchanti, sotāpattiphalampi
sacchikaronti, sakadāgāmiphalampi sacchikaronti, anāgāmiphalampi
sacchikaronti, arahattampi sacchikaronti, ye cime dibbā gabbhā
paripācenti dibbānaṁ bhavānaṁ abhinibbattiyā, tesaṁ antarāyakaro hoti,
antarāyakaro samāno ahitānukampī hoti, ahitānukampissa sapattakaṁ
cittaṁ paccupaṭṭhitaṁ hoti, sapattake citte paccupaṭṭhite micchādiṭṭhi
hoti.
DN 12

The term 'kālakiriyā' is generally spoken by Noble Ones, such as by the stream-enterer householder Nakula's Mother, in relation to the ending of life or 'completion of time', as follows:

Householder, don't pass away with concerns.
Mā kho tvaṁ, gahapati, sāpekkho kālamakāsi.
Such concern is suffering,
Dukkhā, gahapati, sāpekkhassa kālakiriyā;
and it's criticized by the Buddha.
garahitā ca bhagavatā sāpekkhassa kālakiriyā.
AN 6.16

Note: 'kālakiriyā' ('completion of time') is not synonymous with 'marana' ('death') because 'kālakiriyā' happens to Noble Ones; where as 'marana' does not happen to Noble Ones. Those who cannot discern this distinction will never understand the essence of the Buddha Teaching.
Therefore, in conclusion, the impression is 'kamma' means 'action' or 'an action';  where as 'kiriyā' may possibly mean 'completion of an action/performance'.
For example, about the word kamma, the dictionary says it can be used in many ways, such as objective, subjective, active, passive,   etc.

New Concise Pali English Dictionary
kiriya
neuter ~ā, .f

doing; > performance; action, activity; what one does or has done; way of acting

morally significant activity which produces effects

karoti
verb
present 3 singular
does, makes; acts; performs; acts for
the advantage or injury of another; (especially absolutive) puts,
places
Sk. karoti, *qṷer to form, to build

Kamma vs. kiriya / kriya


Shopping during Pesach

Question: Should one go to the store to shop during Chag haMatzot (Pesach), being that we have to stay away from chametz and leavening agents during the time?
Comment: Shopping for what? Electronics? Clothing? Food? Anything?
Comment: Grocery stores.
Answer: Ex. 13:17 states:

מצות יאכל את שבעת הימים ולא יראה לך חמץ ולא יראה לך שאר
בכל-גבלך
Masoth shall be eaten throughout the seven day period; no hames may be
seen in your possession, nor may leaven be seen in your possession in
all your borders.

One might erroneously conclude that seeing in and of itself is prohibited. However the word לך (your) teaches us that though we are prohibited from retaining possession of hames, we are not prohibited from seeing the hames of others.
This is as is stated in H. Hames u'Masah 3:1:

לא יראה לך שלך אי אתה רואה אבל אתה רואה של אחרים
"No [leaven] shall be seen for you." [We may infer]: You may not see
your own [leaven]. However, you may see [leaven] belonging to others

See there for further details (e.g. the permissibility of seeing hames owned by a gentile that was left with a Jew over Passover, etc.).
Accordingly, there is no problem with shopping or venturing out into the gentile world where one may visually encounter hames. The important thing is that we do not take any into our possession.

Shopping during Pesach


MVC Design for an app using RestKit

Question: I'm trying to create an app that follows MVC as closely as possible using RestKit. The goal is to incorporate RKObjectMapping and RKObjectManager so that my objects can be loaded using [[RKObjectManager sharedManager] loadObjectsAtResourcePath:@"/object" delegate:self].
In my current design, I have the following:
Objects
- MYBaseObject : NSObject
- MYObjectA : MYBaseObject
- MyObjectB : MYBaseObject
...
ObjectControllers
- MYBaseObjectController : NSObject
- MYObjectAController : MYBaseObjectController
- MYObjectBController : MYBaseObjectController
...
ViewControllers
- MYBaseViewController : UIViewController
- MYViewController1 : MYBaseViewController
...

I also have introduced a delegate called MYBaseObjectControllerDelegate that acts as an adapter/wrapper for different things that may involve delegation (like asynchronous requests), as well as in case I decide to not use RestKit in the future.
1) Ideally, I would like to be able to do the following in MYViewController:
self.arrayOfMYObject = [MYObjectA allObjectsWithDelegate:self];

I can't seem to figure out a way to get that sort of thing to work, however, using delegation. The problem is that I need to somehow return the response value and there is no way I can think of to do that using only delegation.
2) I would like to know where the various RestKit declarations of RKObjectMapping and such should reside. Should they live in the respective controllers for each of the Objects, or should they live in the objects themselves? What would be an appropriate structure?
Being new to RestKit I would like to get it as "right" as possible the first time around to avoid major refactoring.
Answer: Check out https://github.com/RestKit/RKGithub as an example app for a possible starting point.
I have successfully adapted this structure to my own applications.
Under this structure, the mapping sits at the root level and is then called on by the controllers.

MVC Design for an app using RestKit