Pumping blood turned into power

Question: How could we use our own heart which pumps our blood, to potentially charge devices such as a cell phone?
Answer: First things first - that's putting a lot of strain on your heart. This system, however it works, will take the mechanical energy out of your blood. This means your heart needs to put more energy into pumping the blood around. While this is temporary since the heart will adapt and grow stronger, it's still going to be an issue.
In addition, the heart only provides about 1.3 watts. Phone chargers run at 2.5+ watts. The heart will have to triple its output to handle the energy of lower-powered chargers.
A better solution would be to run a charger off the user's blood sugar. Humans cosume power at an average of around 97 watts throughout the day. Most phones only take a few hours to charge, so that's going to be less than 5 watts average.
Comment: Watts are Joules per second. There is no reason you couldn't charge a battery at a lower wattage over a longer period of time. If a charger charges at 2.5 watts over say 3 hours, that's ~27kJ total energy stored. If you can deliver 0.1 watts of power from your heart, it would take ~75hrs to charge the same battery.
Comment: FYI: A modern phone taking a few hours to charge includes a good part (around half) at a peak rate of 10–15W, with that declining as the battery gets fuller.
Comment: @MadPhysicist There is a lower limit—the practical ones is that you need to put energy into the phone faster than it uses it. Most folks would run their phone completely dead in under 48h. So if you're adding energy slower than that (like your 75h charge), you won't keep up with it being spent. (Also, I suspect many phones will refuse to charge at all if given less than the USB1 current of 500mA = 2.5W. Go under 100mA = 0.5W and the port may not even register.)
Comment: @derobert. Sure, you would have to charge the battery when it is not being used only to have it discharge at three times the charging rate, but it's possible, at least from and energy-conservation standpoint.
Comment: What does "Most phones only take a few hours to charge, so that's going to be less than 5 watts average." mean? Where does that come from?
Comment: @MadPhysicist I believe that's providing an upper bound for the 2.5 lower bound stated in the previous paragraph.
Comment: Really cool idea, but I'm not sure how that is World Building.  You might try a biology or physics exchange.
Comment: @ozone this post answers the question. Don't tell the person answering to post on a different site. If you have a problem, then go tell the asker.
Answer: Not fiction!
http://www.dailymail.co.uk/health/article-2228025/Pacemaker-powered-heartbeat-instead-batteries--smaller-cent-coin.html
These batteries turn the motion caused by the pumping heart into electrical charge.  It is not a perpetual motion machine because the signal from the pacemaker simply triggers the beat; it does not provide the energy for the beat.
I found news about this going back to 2008.
Answer: While the real world numbers don't quite line up (cell phones require much more power currently than the heart produces), this idea has already been transformed into a conceptual art piece entitled: Energy Addicts by Naomi Kizhner.
Answer: Is there any particular reason you'd choose the heart? There are much bigger and more powerful muscles in the body, that you can access without invasive surgery. I would suggest glutes and hamstrings are better suited. Look at Team New Zealand's recent America's Cup yachts for a real world example of using power from cyclists' legs to power the hydraulic systems of a boat. I've seen a similar setup connecting exercycles to generators to charge cellphones in an airport.
Answer: The main problem to solve is that our energy is chemical and it remains chemical for power conversion. Even our "low-voltage", information transfer systems (= nerve systems) works mainly on a chemical way: the nerves aren't cables transmitting electrons, rather sodium and potassium ions exchange place in the synapses.
Our "high power", i.e. energy transfer system happens in the blood. Blood sugar is used to transfer energy. Inside the cells, this sugar is used in the cytric acid cycle to convert ADP to ATP. The ATP moves our muscles while it converts back to ADP. But this happen deeply inside the cells.
Extracting energy from a living human, and convert it to electricity to drive an implant, means that we have to somehow convert the blood sugar to energy. It may be possible by some fuel cell-based technology.
If the implants to drive are inside the body, then from this point the system can be electronic.
If it is out of the body, you have to somehow put it through the skin. Note, cables sticking out from a human body are never healthy, the only way for a long-term solution if the skin remains intackt. Fortunately, there is already technology to transfer power by radio waves, here is an example to load phones without plugging them. The same could work also through the skin.
Note, making this on a way what doesn't poison you requires the development of a whole new medical technology. Although the research/development is on the way.
Its first human-friendly usage will be probably to drive artifical hearth implants.
In a dystopia it could be used also for many things, for example to

identify people
restricting them (Relevations 13:17: "It also forced all people, great and small, rich and poor, free and slave, to receive a mark on their right hands or on their foreheads, so that they could not buy or sell unless they had the mark, which is the name of the beast or the number of its name.")
releasing poison into their blood stream from wifi
Answer: Drawing energy from blood sugar is not necessary. The device itself could have used  a sugar solution instead. The heart just moves food and oxygen to tissues and does not generate that much power.
Muscle power is the best. For that, you can harnrss leg power. A series of piezo electric crystals can turn changes in pressure into elrctricity. Yoi can mount them at the soles of your shoes and start walking
https://www.google.co.il/amp/www.instructables.com/id/Piezoelectric-Shoes-Charge-Your-Mobile-Device-by-W/%3famp_page=true
Answer: For a story idea you could do something along Faraday's law.
Instead of having the blood drive a rotor to generate power or tap into the sugar stores of the person, you could have a person injected with tiny magnets.  These magnets theoretically would be pumped around the body without doing harm or putting a huge load on the heart.  You then have coils of wire, either in a full body suit or localized to a sleeve/pant leg that would generate a current as the tiny magnets pass thru it.
Think of what happens when hydro power is made.  The water spins a rotor that turns a giant magnet encased in copper windings.  As the magnet moves it induces current in the wires.  In this case the magnets flowing in your blood would simulate the spinning magnet and the body suit of jacket could act like the windings around the generator.
Yeah, there's no way it could happen as the magnetic fields would be so small but it's kind of a kewl jumping off point for a sci-fi premise.  You could even write it with the iron in the blood being magnetized instead of having the addition of magnets.

Pumping blood turned into power


numpy: How do you "break" a numpy operation?

Question: I accidentally tried to make a 200,000 x 200,000 array in numpy.  Control-C does not seem to break the operation.  Is there any way to stop the array creation without simply killing the python session?
Answer: Unfortunately no.  Python (and MatLab, the only other analysis package I use) do not detect the user interrupt until the current operation (NOT run) is finished.
Answer: The reason this doesn't work is that numpy has large portions written in C.
When Python begins executing a compiled function, the Python signal handling is effectively paused until the execution of the compiled code is finished.
This is bad news for your interactive Python session, but there isn't much you can do aside from waiting for the inevitable OutOfMemoryError, or killing the session.


What did Jesus mean in John 4:22, ὑμεῖς προσκυνεῖτε ὃ οὐκ οἴδατε?

Question: What did Jesus mean in John 4:22, ὑμεῖς προσκυνεῖτε ὃ οὐκ οἴδατε (You worship what you do not know; ESV)? Why is the neuter relative pronoun used in both statements: ὑμεῖς προσκυνεῖτε ὃ οὐκ οἴδατε· ἡμεῖς προσκυνοῦμεν ὃ οἴδαμεν, (You worship what you do not know; we worship what we know, ESV)?
Comment: No, πνεῦμα being neuter has nothing to do with the relative pronoun that precedes it. The first mention of spirit is to the human spirit and is in conjunction with truth (feminine noun) and there is too much distance between the pronoun and the mention of spirit related to God in v.24 (and even then, that reference implies it refers to a quality of God, not a reference to His Spirit... though that is open to interpretation).
Comment: Some good answers and I'm trying to decide which is the best.  One thing I'm wondering about.  Is there any chance the relative pronoun is neuter because πνεῦμα is neuter?  i.e. they are not worshiping God as Spirit or in spirit.
Answer: A use of the masculine pronoun (ὅς) would have been a reference back to "the Father" (τῷ πατρί) immediately preceding as the antecedent. But Jesus is not wanting to say the Samaritans worship the Father who they do not know.
Rather, he is trying to point out that they are caught up in worshiping something else entirely—a false idea, a concept of a god, not the true God. So they themselves do not really have a knowledge of what they are worshiping (which is true of all false religions), and hence the neuter relative pronoun.
Most likely Jesus continues using the neuter when describing what "we" (the Jews) worship for two reasons:

It parallels to the statement he just made to the Samaritan, so it keeps the two ideas on the same plane of thought, which relates to #2...
His focus here is on the conceptual understanding of/relationship to one's deity, which the Jews did have a true(r) knowledge of God (God had set His place of worship in Jerusalem, which is the question she asked [v.19] that elicited the response of v.20).

That some false conceptions are a focus can be found as well in some commentaries (though these do not necessarily mention the neuter):

Jesus did not leave the woman with a vague witness about God. He pushed her to think about the personal God who acts in history. First, he called her to an eschatological reality (the coming hour) that would affect all worship (4:21). Because God has acted primarily through people in the world, he is not basically building-oriented. The mention of "hour" here is a Johannine theme that encapsulates the decisive moment in history of the crucifixion and resurrection that transformed and continues to transform human reality. Second, Jesus reminded her that salvation is directly related to God's working in history (4:22). The issue was not a matter of national or tribal pride. That was the woman's perspective on God and religion. ... The issue, however, was understanding how God had chosen to reveal the divine purpose in history. (Gerald L. Borchert, John 1–11. Vol. 25A. The New American Commentary. Nashville: Broadman & Holman Publishers, 1996.)

Jesus now responded directly to the implied question in 4:20: You Samaritans worship what you do not know; we worship what we do know, for salvation is from the Jews. The plural forms used by Jesus ('you Samaritans' and 'we [Jews]') show that his remarks related to the Samaritan people and the Jewish people in the same way as the implied question of the woman did. Jesus insisted that Samaritan worship on Mount Gerizim was worship based upon ignorance. Jewish worship in Jerusalem was based on knowledge because it was in line with the revelation of God to his people. They worshipped at the place God himself had chosen. Jesus also insisted that God's purposes for salvation were being worked out through the Jewish people, not the Samaritans. No matter how much grace Jesus was to show to the Samaritan woman, it would not be at the expense of truth. (Colin G. Kruse, John: An Introduction and Commentary. Vol. 4. Tyndale New Testament Commentaries. Downers Grove, IL: InterVarsity Press, 2003.)

One older commentary that does address the neuter more specifically, also giving a summary of various interpreters views (bolding and italics original to commentary):

Ye worship that which ye know not.—The question concerning the where of worship could be resolved only by the what, and this again by the how. The neuter instead of whom is significant. Just because God is not truly known to them, He is a ὅ rather than a ὅς, more impersonal than personal. Meyer supposes that the neuter denotes God in His essence and substance; Lücke, that it denotes τὰ τοῦ θεοῦ, which does not suit the term προσκυνεῖν. De Wette: "O refers to the act of προσκυνεῖν; ye worship, and therein do what ye know not. Brückner objects to the correctness of the sentence, that the Samaritans were monotheists. But there are different monotheisms. Tittmann and others explain: Pro vestra ignorantia. Tholuck (after Lücke): "The true knowledge is that which is shaped by the history of redemption; and the Samaritans who were limited to the Pentateuch for their sacred books, knew Jehovah, that is, the historical God of Israel, but partially." As a whole, in a living growth of knowledge, they almost knew Him not. This accounts also for the ὅτι.
We worship that which we know.—Designating the Jewish fellowship in its living unity, as represented in fact by Himself. [The ἡμεὶς in the mouth of Christ in relation to God, is without example, but is easily explained by the fact that here He speaks as a Jew, defending the Jewish worship as the true one against the Samaritan. Otherwise He always calls God His Father, and puts Himself, as the only begotten Son, in a unique and exclusive relation to Him. In vers. 23, 24 He drops the ἡμεῖς and speaks of the Christian worshippers in the third person.—P. S.] (John Peter Lange and Philip Schaff, A Commentary on the Holy Scriptures: John, New York: Charles Scribner & Co., 1871; elec. edition, Bellingham, WA: Logos Bible Software, 2008.)

Conclusion
So the neuter pronoun is allowing for a reference to a false conception of God as one's focus of worship, not a reference to worshiping the true God with some lack of knowledge that a use of the masculine would have implied.
Comment: +1 Did you see [Dan Wallace's comment](https://books.google.com/books?id=XlqoTVsk2wcC&lpg=PP1&pg=PA337#v=onepage&q&f=false) on this (p. 337)? "In Jesus' response to the Samaritan woman about worship, he noted in v 21 that true worshipers will worship the Father (ὁ πατήρ).  He continues with the principle articulated in v 22, but this time uses the neuter pronoun to describe the object of worship. The implication seems to be that, since he is aligning himself with his people (not with true worshipers per se), he grants them doctrinal fidelity but not spiritual relationship."
Comment: @Susan No, I did not think to look at Wallace for a specific example of this verse. That adds another perspective (though I do not think I agree with Wallace on what he feels the implication is).
Answer: I think the neuter relative pronoun can be best understood as referring to an implicit demonstrative, along the lines of:

You worship [that] which you do not know.  We worship [that] which we do know

In saying ὑμεῖς προσκυνεῖτε ὃ οὐκ οἴδατε - "You worship [that] which you do not know" - Jesus is essentially saying that the Samaritans, being ignorant of the true God,  worship Him in name only.  Gregory of Nyssa (c 334-395) explained the passage:

Ye worship ye know not what, the Lord speaks to the Samaritan woman, prejudiced as she was by corporeal ideas in her opinions concerning God: and to her the phrase well applies, for the Samaritans, thinking that they worship God, and at the same time supposing the Deity to be corporeally settled in place, adore Him in name only, worshipping something else and not God ...1

But He rather quickly adds that even though the Jews may worship the true God at that particular moment, it has no bearing on the future (v.22-23):

We know what we worship ... but the hour cometh, and now is, when the true worshippers shall worship the Father in spirit and truth

One modern Orthodox commentary explains:

The Lord did not address the question of who was right, the Samaritans or the Jews, with regard to the proper place of worship.  On the contrary, as St. John Chrysostom2 points out: "... having taken away from both of the places priority in dignity, He rouses her soul by showing that neither Jews nor Samaritans possessed anything great in comparison with that which was to be given."3

1. Against Eunomius, III.5
2. Homily XXXIII on John
3.  Dmitry Royster, The Holy Gospel According to Saint John: A Pastoral Commentary (St. Vladimir Seminary Press, 2015), p.105
Answer: The neuter pronoun is used by Jesus' for his own God as well, so the arguments that claim it was used to denote an impersonal (idol) god are misguided. The conversation is like, "You worship something what you don't know, we worship something what we know". I think neuter relative pronoun (ho ὅ instead of ὅς) for masculine for a special purpose. It could refer more to the abstract nature of the object rather than the gender and identity. In the most fundamental nature, everything can be described as a thing (neuter). It is fortunate that the modern versions still keep the neuter relative pronouns in many such cases, without violating the basics of English grammar, as they do with the pronoun neuter pronoun for the Spirit. Also, there is a thing called attraction, where sometimes the case or gender of the relative is attracted to that of the antecedent (known as attraction or direct attraction). The relative pronoun for example here for God is attracted to the relative (abstract entity) rather than the original gender or identity.

οὐκέτι εἰσὶν δύο ἀλλὰ σὰρξ μία. ὃ οὖν ὁ θεὸς συνέζευξεν
ἄνθρωπος μὴ χωριζέτω.     they are no longer two but one flesh. What
therefore God has joined together, let not man separate (Matt 19:6)
χάριτι δὲ θεοῦ εἰμι ὅ εἰμι.
but by the grace of God I am what I
am (1Cor 15:10)
παρακαλῶ σε περὶ τοῦ ἐμοῦ τέκνου, ὃν ἐγέννησα ἐν τοῖς δεσμοῖς   Ὀνήσιμον
I appeal to you for my child, Onesimus, whose father I
became in my imprisonment. (Philemon 10)

Teknon for child is a neuter, but the masculine relative pronoun (hon) is used because the antecedent Onesimus isn't really a child. Neuter is used by Paul for himself. Neuter is used for something God has joined.
Answer: Here is what I get from the Greek:

You, yourselves, worship one whom you have not known. We worship one whom we have known, as salvation is of the Jews.
  -- John 4:22

Details:

The relative pronouns are neuter because they are not referring to anything gender specific in the context.
Additional note:
The neuter gender is used in regard to persons (including God) when the gender of the person is immaterial to what is being said. Clearly, the intent of Jesus' use of the neuter gender here is because he knows full-well that the Samaritans believe they worship God, but they don't know/understand/recognise who it is they are worshiping. If they did, they would not be concerned upon which mountain they should worship. Of course, the Jews with whom Jesus had been contending (the leaders and elders and teachers of the people) had no deeper knowledge/recognition/understanding of this God than the Samaritans.
Here is an example of John making use of the neuter gender in regard to those who will be raised up on the last day:

Therefore this is the desire of him who sent me: that of each one he has given me I should lose none of them, but I should raise them up on the last day.
  ‒ John 6:39

Details:

Without this understanding of the neuter gender, one could legitimately conclude that only men will be raised up on the last day.

Back a few verses in John 4:18, Jesus says:

... and the man you have at present is not your husband ...

Details:

The relative pronoun here is masculine because it refers to a man/husband in the context.

Skip forward some verses in John 4:32, Jesus says to his disciples:

... I, myself, have meat to eat which you have not known.

Details:

Here the relative pronoun is feminine because it refers to the "meat", which is feminine.

What I wonder about this verse is why almost all the versions have gone with "what" instead of "whom". Both are gender neutral, so either is appropriate in the context. Except that, the Jews worship a "who" not a "what" -- Jesus did, at least.
I believe this may have been the issue that gave rise to the OP's question. The NLT translators are on the same page, as they have given:

You Samaritans know very little about the one you worship, while we Jews know all about him, for salvation comes through the Jews.
  -- John 4:22 (NLT)
Comment: -1 The difference between "what" and "whom" in English is that the latter is used almost exclusively to refer to people (including God in some forms of theology). Greek rarely uses a neuter pronoun to refer to a person. Rather, the masculine is used for gender neutral/undefined yet personal referents. The switch from ὁ πατήρ to the neuter ὃ is striking, as noted by the OP and other answers, and as captured in most translations.
Comment: @Susan your first sentence confirms my choice of "whom" rather than "what". When you say "rarely" in your next sentence, then clearly you are aware of instances where a neuter pronoun is used to refer to a person. So, while I understand the reason for your comment, I am dumbfounded by the need for your downvote.
Comment: Nope, the "rarely" was just because of a general feeling that there is likely an exception to be found somewhere and I'm not interested in arguing if/when you find it. (And DV is appropriate for something I believe to be incorrect. The comment was a courtesy because I think I recall you being unhappy previously about DV without comment, though I may be misremembering; my apologies if so.)
Comment: @Susan `Nope, the "rarely" was just because of a general feeling that there is likely an exception to be found somewhere and I'm not interested in arguing if/when you find it.` Your words need to be preserved in case of they inadvertently disappear.


Does the fact that China owns nuclear weapon improve the status of Chinese expat?

Question: According to Chinese government propaganda, it is because of the development and deployment of nuclear weapons that the status of Chinese ex-pats is no longer discriminated against by anyone else. Are there any documents or research that can prove that there is a direct link between the increasing military might of the PRC and the fact there are fewer anti-Chinese riots and discriminatory acts against a Chinese in western bloc nations (US, Canada, Europe in particular) between mid-1960s to 1990s
Comment: There are (relatively) many anti-Asian hate crimes in the United States, with an increase due to the COVID-19 pandemic. A lot of these are against Chinese people. So the argument that there is no longer discrimination seems to fail on the surface. Are there fewer than in the past? Sure, and there are also fewer anti-Irish and anti-Italian crimes, but neither of those countries has nuclear weapons. Also, no one believes that China would employ nuclear weapons against countries where Chinese immigrants were being discriminated against, so a deterrent effect seems unlikely.
Comment: @Nat - That seems like an easy way to get confounding variables. Maybe anti-Chinese crimes decreased around the time of the US civil rights movement, which was also around the time China developed nuclear weapons. Or maybe China's increased wealth both enabled military advancement and raised the country's profile enough to combat stereotypes.
Comment: There'd be a lot to check in that claim -- for example, we'd want to check that Chinese ex-pats actually are less discriminated against since China's gotten nuclear weapons, then check if there's some appreciable causation.
Comment: Maybe the easiest way would be to have some survey of ex-pat discrimination over time vs. when their home-country went nuclear?
Comment: @Obie2.0: If there's an apparent-correlation, then sure, it wouldn't establish causation.  Though if there's no correlation, it'd seem helpful.  And the hypothesis seems pretty weak, so it might be prone to easy refutation.
Comment: Is this even an oft-repeated propaganda line to be worthy of an investigation? Because with billions upon billions of "brainstorming" nationalistic posts on the Chinese social media networks... one is bound to find "gems" like this. For the record, I'm not among the downvoters, it just that this seems a rather obscure (and fairly improbable) claim to me. I mean China's standing as world power was definitely improved by having nuclear weapons. How much that might have reduced anti-Chinese sentiment or racism is going to be hard to quantify.
Answer: As the saying goes, history is an experiment with N=1. (That is, we don't have a second history where China did not have nuclear weapons, to compare. Or a third, and a fourth, and more, to do statistics.) I believe the following is obvious:

The status of Chinese expat communities has improved because China is a superpower. One would also have to talk about where.  If there is upheaval somewhere in the world, one expects the US government to organize an airlift for their citizens. One expects the EU to try, and to be a little less effective than the US. In parts of the world, China also does things like that.
China's status as a superpower is enhanced by nuclear weapons.

What is arguable is just how much of that superpower status is due to the nuclear weapons. China traditionally had a concept of minimal nuclear deterrence, that is enough weapons to make a painful counterstrike, but no attempt to outfight the adversary. That, and a traditional lack of global military reach, reduced the impact of the military on Chinese status.
China has gotten more assertive lately, but mostly not in the nuclear arena. See page 138 of this RAND study.


connect through WAN gateway to host through vbox to VM through nginx proxy to odoo

Question: I put a port forward on my Comcast xfinity gateway to my Ubuntu host PC.
The Ubuntu host runs VirtualBox where I defined a forward port from the one from the gateway to an Ubuntu VM which hosts my Odoo app.
Odoo has a builtin web server (Werkzueg or something like that) that does not support HTTPS, so I installed nginx on the VM to proxy/reverse proxy Odoo using HTTPS.
Internet --> modem port forward -->  Ubuntu host --> virtualbox port forward --> Ubuntu vm --> nginx --> Odoo
One thing:  without nginx installed, and using plain HTTP, I can connect to my Odoo app from my tablet at the restaurant no problem.  Only I don't want to do that.
Modem is TECHNICOLOR CGM4140COM which does support port forward.
nginx.conf:
user www-data;
worker_processes auto;
pid /run/nginx.pid;

events {
    worker_connections 768;
    # multi_accept on;
}

http {

##
# Basic Settings
##

sendfile on;
tcp_nopush on;
tcp_nodelay on;
keepalive_timeout 65;
types_hash_max_size 2048;
include /etc/nginx/mime.types;
default_type application/octet-stream;

include /etc/nginx/conf.d/*.conf;
include /etc/nginx/sites-enabled/*;
}

default.conf:
deleted

odoo10.conf
#odoo server
upstream odoo {
server 127.0.0.1:8069;
}

# http -> https
server {
listen 80;
server_name odoo.mycompany.com;
rewrite ^(.*) https://$host$1 permanent;
}

server {
listen 443 ssl;
server_name odoo.mycompany.com;
proxy_read_timeout 720s;
proxy_connect_timeout 720s;
proxy_send_timeout 720s;

# Add Headers for odoo proxy mode
proxy_set_header X-Forwarded-Host $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-Real-IP $remote_addr;

# SSL parameters
ssl on;
ssl_certificate /etc/nginx/ssl/odoo10.cert;
ssl_certificate_key /etc/nginx/ssl/odoo10.key;
ssl_session_timeout 30m;
ssl_protocols TLSv1.2;
ssl_ciphers HIGH:!aNULL:!MD5;
ssl_prefer_server_ciphers on;

# log
access_log /etc/nginx/odoo10.access.log;
error_log /etc/nginx/odoo10.error.log debug;

# Redirect requests to odoo backend server
location / {
proxy_redirect off;
proxy_pass http://odoo;
}

# common gzip
gzip_types text/css text/less text/plain text/xml application/xml
application/json application/javascript;
gzip on;
}

From the internet I can connect to my Odoo app with https and it works to some extent.  But there are some problems I'd like to solve.
When I enter https://my-modem-IP:port I will receive my modem admin login page.  So I need to enter https://my-modem-IP:port/web/login.  When I do this I receive the Odoo login page. And the URL that is returned back is the same as I sent: https://my-modem-IP:port/web/login.
When I click on that I again receive the modem admin login page with https://my-modem-IP/web   -- no port#.
If I manually enter the port# to that URL -- https://my-modem-IP:port/web -- I am logged into the Odoo app.  I have not tested the complete app, but so far there is no problem navigating through it, except for the logout page which again drops the port# and sends me the modem admin logon page.
I have two debug logs: one that gives me the login problem and another that shows it works when I manually enter the port#.  They are quite large and maybe this is not the place to include them.  I hope someone will let me know a way I can post the logs.
Answer: I fixed it.  I added the desired port# as follows:
proxy_set_header X-Forwarded-Host $host:6789;
I also eliminate the listed on 80 since I will not accept it anyway.  I only accept https.


Combinatorial interpretation for Vandermonde's identity $\sum\limits_i\binom{m}{i}\binom{n}{j-i}=\binom{m+n}{j}$?

Question: A known identity of binomial coefficients is that
$$
\sum_i\binom{m}{i}\binom{n}{j-i}=\binom{m+n}{j}.
$$
Is there a combinatorial proof/explanation of why it holds? Thanks.
Comment: We have $m$ Martians and $n$ Neptunians, and want to select a crew of $j$ "people".  The right side gives the number of ways. So does the left side, since we can choose $0$ Martians and $j$ Neptunians, or $1$ Martian and $j-1$ Neptunians or $\dots$.
Comment: This is [Vandermonde's identity](http://en.wikipedia.org/wiki/Vandermonde%27s_identity). A combinatorial proof is given at wikipedia and at [proofwiki](http://www.proofwiki.org/wiki/Chu-Vandermonde_Identity). See also this question: http://math.stackexchange.com/questions/76819/
Comment: Either of those could be posted as an answer.
Answer: The captain of the pirate starship Free Enterprise finds $m$ Martians and $n$ Neptunians in a bar.  In how many ways can she select a crew of $j$ creatures  for a raid on Jupiter?
The right-hand side $\binom{m+n}{j}$ counts the number of ways to select $j$ creatures from the $m+n$ creatures available.
So does the left-hand side.  For she could select $0$ Martians and $j$ Neptunians. This can be done in $\binom{m}{0}\binom{n}{j}$ ways.
Or else she could select $1$ Martian and $j-1$ Neptunians. This can be done in $\binom{m}{1}\binom{n}{j-1}$ ways.
Or else she could select $2$ Martians and $j-2$ Neptunians.  This can be done in $\binom{m}{2}\binom{n}{j-2}$ ways.
And so on.  Thus the number of ways to recruit $j$ creatures is given by the sum on the left-hand side.
Comment: The result, and the reasoning, remain correct even if, for example, $j>n$. All we need to do is to define  $\binom{u}{v}$ to be $0$ if $u<v$.
Answer: What you need to prove is the Vandermonde's identity.
Vandermonde's Identity states that $\sum_{k=0}^r\binom mk\binom n{r-k}=\binom{m+n}r$, which can be proven combinatorially by noting that any combination of $r$ objects from a group of $m+n$ objects must have some $0\le k\le r$ objects from group $m$ and the remaining from group $n$.


Changing my rear wheel tyre from 26 x 2.1 to 26 x 2.0: what's the difference?

Question: Firstly, would a 26 x 2.0 tyre fit, and would there be a noticeable difference compared to my original tyre? (I am going from 2.10 to 2.0)
Comment: From 2.1 to 2.0 there will be no noticeable difference. That is only a change of 2.54 millimeters of width. Also not all listed tire sizes are perfectly accurate so you may have no difference at all.
Answer: I am reasonably assured the larger tire will fit. As has been stated here before, bicycle tire width sizes aren't an exact standard. Maker A's tire size 2.0 inch may in fact be larger than Maker B's 2.1. The best information comes from user reviews about a specific model. Just to be sure look at your current tire. Does it barely fit between the frame stays? When on the smallest front sprocket how close is the front derailleur from hitting the tire. If the tolerances are very close the larger tire may not fit. Tire design also comes into play. A full knobby tire ( WTB velociraptor)  may hit while a microknob  (Geax AKA) may have enough clearance.
Comment: he is going from 2.1 -> 2.0 in my understanding
Comment: That is my point you have no way of knowing if a different  brand, type or size is physically larger or smaller than the original.
Comment: I'm tempted to change "I am reasonably assured the larger tire will fit" to "I am reasonably assured a similar-sized tire will fit" and that while 2.0 is nominally 5% smaller, it could end up slightly wider than a 2.1 because of manufacturer tolerances.
Comment: That is from where my comment arose, as the larger marked tire is already on the bike so yes it will fit..
Comment: Again my point is just because one tire is sized 2.0 inches, it is not  a given fact that it will be smaller than a different brand or tread type  sized 2.1 inches. There is no standard for width specifications, it is what the manufacturer  decides  to call it.


Java modulo operator precedence

Question: I need some help in debugging the following java program.
import java.util.Random;

public class NextInt
{
    public static void main(String[] args)
    {
        for(int i=0; i<20; ++i)
        {
            if(i>0)
                System.out.print(", ");
            int x = (new Random()).nextInt();
            System.out.print( x % 2 + 1);
        }
        System.out.println("");
    }
}

Will output (for example):
0, 1, 0, 1, 2, 2, 2, 0, 0, 1, 1, 1, 2, 0, 1, 1, 1, 1, 2, 1

I think the output should have been containing only ones and twos! If we think about the x % (2+1) interpretation then the output is correct. Is the modulo operator really weaker than the addition? Java tutorial says no. Or is there something else that I am missing?
Comment: Admittedly it doesn't really matter for this example, but for good practice you should generally re-use the same random object rather than constantly creating one and throwing it away.
Comment: Yes. The original code generated only one random number that produced crazy values. I tried to not change many things, so I just copied what whas there. :-) Thanks!
Answer: this is because a negative number % 2 = -1 and then +1 results in 0.
;)
Comment: `Math.abs(x) % 2 + 1` it is :-)
Answer: Note that
Random.nextInt()

may produce negative ints and that, in Java, the result of the remainder operator ('%') takes the sign of the left-hand operand.  This differs amongst programming languages - see this table in the Wikipedia entry for Modulo for a sampling.
If you wanted just non-negative ints, use:
Random.nextInt(Integer.MAX_VALUE)

to produce ints between 0 (inclusive) and 2^31-1 (exclusive). Otherwise, if you wanted to handle the possible negative result of modulo and still get back just 1's or 2's, then use:
System.out.print(Math.abs(x % 2) + 1);

===
JavaDoc for Random.nextInt (emphasis is mine):

public int nextInt() Returns the next pseudorandom, uniformly
  distributed int value from this random number generator's sequence.
  The general contract of nextInt is that one int value is
  pseudorandomly generated and returned. All 2^32 possible int values
  are produced with (approximately) equal probability.
public int nextInt(int n) Returns a pseudorandom, uniformly
  distributed int value between 0 (inclusive) and the specified value
  (exclusive), drawn from this random number generator's sequence.

===
Java Language Spec regarding the sign of the result of '%'

... It follows from this rule that the result of the remainder operation can be negative only if the dividend is negative, and can be positive only if the dividend is positive. ...
Comment: `new Random().nextInt(2) + 1` will be the final solution. Thanks!
Answer: Modulo-ing a positive number in Java with a negative one will returning a negative result - which is probably where you're getting behaviour you don't expect.
Perhaps you want something like:
System.out.print(Math.abs(x % 2) + 1);

This isn't precisely defined as far as mathematics go, and thus different languages will implement this in different ways - so it's something to watch out for generally. In Pascal for instance, the result will be positive (as you probably expected for this example), and in C89 at least, it's undefined and thus could do either!
Answer: Guava's IntMath class offers an always positive modulo operation:
System.out.println(IntMath.mod(x, 2) +1);

Java modulo operator precedence


Unspecified Error in Sql Server Management Studio

Question: I just started getting an error window with "Unspecified Error" in MS Sql Server Management Studio 2005. I get this when trying to Create a New Table in a DB or Right Click > Design on an existing table. I am able to open up a new connection and query the DB without any problems. The error message obviously is no help. Any thoughts on what is the cause and how to fix this?
Comment: Did you install any plug-ins? In my experience, that can break Management Studio quite effectively.
Comment: No Plugins. The only thing that I have installed recently is an upgrade for Windows Live Messenger and Writer.
Answer: I realize this answer is a little late in coming, but I just ran into this same issue.
Strangely enough, the error seems to go away if I use SQL Server Authentication rather than Windows Authentication. If you don't have that as an option or that doesn't work for you, I suppose you'll need to resort to old fashioned SQL statements.


Will Allah forgive me for this bad dua?

Question: i did a bad dua and i said "Allah dont forgive me even if i felt regret about doing this dua".i felt regret and sadness about asking this dua so i repented.Will allah still forgive me or no?
Comment: Deleting this question after you got an answer is incredibly disrespectful for the user who put in the time and effort to answer it.
Answer: Assalamu alaikum
Firstly, we should be careful about which duas we ask before we ask them. Asking for something haraam is not answered by Allah anyway as He wouldn't answer an haraam dua.
The fact that you repented is the correct start though. Allah knows what is in the hearts of everyone. He knows what we don't know and His mercy encompasses all things. He knows also that we are human and that we can falter. So never give up on His mercy. Whenever we commit a sin we should meet 4 conditions for our sin to be forgiven, this is any sin committed between you and Allah which doesn't involve another human being:

admit your sin
regret your sin
ask Allah to forgive you for that sin
promise not to do the sin again whilst doing everything possible to stay away from that sin, even if it means breaking up with certain evil company of people, stop watching certain things on TV, giving up certain habits etc which may have lead to that sin in the first place.

Thereafter if we were to commit that same sin again, even a hundred times, due to our human weakness and the shaitaan's temptations being too much for us, if we were to meet those same 4 conditions again there is absolutely no reason why Allah wouldn't forgive us so long as we don't associate partners with Him in worship of course and so long as it really is due to human weakness (Allah knows). This is the condition for sins committed not involving anyone else.
However in the case of the sin involving one of Allah's creatures (or another human being) then you must first ask that person to forgive you as it's their right above yours. If they forgive you that's great. However if they don't then they gain some of your good deeds on the Day of Reckoning. This applies to everyone you wrong until eventually you have no good deeds left. This would also be the case of those doing wrong to you of course (you get their good deeds). But it is best for one to forgive as Allah loves forgiveness.
If Allah has forgiven your sin but you still keep feeling regret and seeking forgiveness for it, it then causes your status to rise so the more someone repents to Allah, the better it is for that person
4 conditions of repentance- Mufti Menk https://youtu.be/DS39foiWhr4
Jundab reported: The Messenger of Allah, peace and blessings be upon him, said, "A man said: By Allah, Allah will not forgive this person! Allah Almighty said: Who is he who swore by me that I will not forgive someone? I have forgiven him and nullified your good deeds." Ṣaḥīḥ Muslim 2621
Say: O my servants! who have acted extravagantly against their own souls, do not despair of the mercy of Allah; surely Allah forgives the faults altogether; surely, He is the Forgiving the Merciful. (Az-Zumar 39:53).
Then hasten on from the Place from which the people hasten on and ask the forgiveness of Allah; surely Allah is Forgiving, Merciful. (Al-Baqarah 2:199).
Surely Allah does not forgive that anything should be associated with Him, and He forgives what is besides this to whom He pleases; and whoever associates anything with Allah, he indeed strays off into a remote error. (An-Nisaa' 4:116).
Surely Allah does not forgive that anything should be associated with Him, and forgives what is besides that to whomsoever He pleases; and whoever associates anything with Allah, he devises indeed a great sin. (An-Nisaa' 4:48).
This link may also help: https://islamqa.info/en/answers/5113/why-doesnt-allaah-answer-our-duaas
I hope this answers your question, in shaa Allah and Allah knows best.
Salaams
EDIT: please everyone who finds my answer helpful upvote me. JzK

Will Allah forgive me for this bad dua?


To show that $M$ is a Banach space under a given norm when $M$ is a space of matrices

Question: I am given a space $M:=\left\{\begin{pmatrix}x&y\\0&x\end{pmatrix}: x,y\in \mathbb{C}\right\}$ with the usual addition and multiplication of matrices.  I want to show that $M$ is a Banach space under the norm $$\left\|\begin{pmatrix}x&y\\0&x\end{pmatrix}\right\|:=|x|+|y|.$$
I have already shown that $\|\cdot\|$ defines a norm on $M$. I want to prove that $M$ is complete. Usually, I pick a sequence $\{f_n\}_{n=1}^\infty$ in $M$ and then show that $\lim_{n\to \infty}\limits\|f_n-f\|=0$ for some $f\in M$. However, these being matrices, I failed to see how such sequences look like. I failed to prove that $M$ is complete.
Comment: Your space $M$ is essentially (read: isometrically isomorphic to) $\mathbb R^2$ equipped with the norm $\|(x,y)\| = |x| + |y|$.
Answer: It is a finite dimensional vector space, and every norm defined on a finite dimensional vector space is complete.


width for  tag in html

Question: Is it possible to set some width to the  tag in html ?
If yes what is the way, if no is there any work around ??
Answer: You can redefine it as a block element and then set width to it: a{display:block;width:400px}.
EDIT: However, in this case it will start on a new line and the next piece of text will also be in a new line. What solves the problem, is inline-block display mode, but this again has problems with older versions of IE and FF (see here: http://caniuse.com/#search=inline-block)
Answer: The css width property does not affect inline elements such as  or .  In order to use block-level properties like width, you'll have to declare your element as a block-level element, using display:block:
Your link

Answer: If You didn't Like display:block or display:inline-block You Can Use The Padding
Comment: How do you use padding?  Can you provide an example?
Answer: As others said, the a element is an inline element and as such not interested in widths or heights. It only looks for the content and makes itself as big as the content requires it to be.
However, depending on what you try to make it look, you can use padding and margin to change the distance to other in-line elements. For example some text adds a 5px padding to the left and the right of the text. But again, the actual size will be based on the text size.
A different approach, which is more a hack, and as such should be avoided if possible, would be the following:

    Some text

This adds a padding of 100px to the right of the text, but by setting the text's position to absolute, that text renders "above" the rest and is ignored for all additional size calculations, so the a element basically has no direct content and as such a width of zero with an added padding of 100px to the right. So the element is exactly 100px wide. And by not modifying the span's positions after setting it to absolute, it will stay where it would have been without the absolute, so it looks the same.

width for  tag in html


Representation of operators in quantum mechanics

Question: For which systems we represent the Hamiltonian as a differential operator and for which system we represent it by a matrix? Can the momentum be represented by a matrix operator?
Comment: You might be also interested in http://physics.stackexchange.com/a/90078/26076 where I look at the QHO and show that we can have both kinds of operators "matrix" or "differential", depending on the co-ordinates we choose.
Answer: If the Hilbert space of the system in question is finite-dimensional, then in a given basis for the Hilbert space, the Hamiltonian (and every other observable for that matter), will be represented by a matrix.
If the Hilbert space is infinite-dimensional, the situation is a bit different.  In Quantum Mechanics, we typically assume that the Hilbert spaces we deal with are separable which means that they admit a countable, orthonormal basis.  The representation of the Hamiltonian in any such basis will be a "matrix" that is "infinite-dimensional."
Consider, for example, the quantum harmonic oscillator.  Let $B = \{|n\rangle\}$ denote the energy eigenbasis where $|n\rangle$ is the energy eigenvector with eigenvalue $E_n = (n+\frac{1}{2})\hbar\omega$, then the Hamiltonian in this basis looks as follows:
\begin{align}
  [\hat H]_B = \begin{pmatrix}
            E_0 &  &  &   \\
             & E_1 &  &  \\
             &  & E_2 &  \\
             &  &  &  \ddots\\
          \end{pmatrix}
\end{align}
Moreover, the momentum operator is also represented as an "infinite-dimensional" matrix in this basis.  Recall that the momentum operator can be written in terms of creation and annihilation operators as follows:
\begin{align}
  \hat p = i\sqrt{\frac{m\omega\hbar}{2}}(\hat a^\dagger - \hat a)
\end{align}
which gives
\begin{align}
  \langle m|\hat p|n\rangle
  &= i\sqrt{\frac{m\omega\hbar}{2}}(\sqrt{n+1}\langle m|n+1\rangle - \sqrt{n}\langle m|n-1\rangle) \\
  &=  i\sqrt{\frac{m\omega\hbar}{2}}(\sqrt{n+1}\delta_{m,n+1} - \sqrt{n}\delta_{m,n-1})
\end{align}
and we can therefore easily write out the first few entries of the momentum operator written in the energy eigenbasis:
\begin{align}
  [\hat p]_B = i\sqrt{\frac{m\omega\hbar}{2}}\left(
\begin{array}{ccccc}
 0 & -1 &  &  &  \\
 1 & 0 & -\sqrt{2} &  &  \\
  & \sqrt{2} & 0 & -\sqrt{3} &  \\
  &  & \sqrt{3} & 0 & \ddots \\
  &  &  & \ddots & \ddots \\
\end{array}
\right)
\end{align}
On the other hand, every state in the Hilbert space can be written in the so-called position $\{|x\rangle\}$ and momentum $\{|p\rangle\}$ "bases."  These aren't strictly speaking bases of the Hilbert space, but they pretty much work the same way in the sense that a given state can be written as a integral over these "continuous" basis elements as opposed to sums over "discrete" bases;
\begin{align}
  |\psi\rangle &= \int_{\mathbb R}dx\psi(x)|x\rangle, \\
  |\psi\rangle &= \int_{\mathbb R}dp\tilde\psi(p)|p\rangle
\end{align}
In this notation, every physical state corresponds to a square integrable function $\psi$ in the position basis and $\tilde\psi$ in the momentum basis.  It is in these "bases" that the various observables are represented by multiplication/differential operators on a function space.  In particular, for example the momentum operator is represented as follows:
\begin{align}
  (\hat p\psi)(x) &= \langle x|\hat p|\psi\rangle = \frac{\hbar}{i}\frac{d\psi}{dx}(x) \\
  (\hat p\tilde\psi)(p) &= \langle p|\hat p|\psi\rangle = p\tilde \psi(p).
\end{align}
In short, the representation of observables, whether they are matrix or differential operator representations, depends on the basis you decide to represent them in.
Comment: @joshphysics- A spin half system, for example, has a finite dimensional hilbert space. Right? We can choose, $S_z$ basis or energy eigenbasis to explicitly write down the $2\times 2$ matrix representation of the operators in this case. Right? For this particular system, is there a concept of position or momentum representation? If yes, how do these operators look? Also I am having the feeling that, momentum operator written in momentum basis or position operator written in position basis can't have matrix representation. Am I right?
Comment: @RoopamSinha Right; spin Hilbert spaces are finite-dimensional and one can, for the spin-$1/2$ Hilbert space for example, represent $S_z$ as a 2-by-2 matrix.  There is no notion of momentum and position representations in these Hilbert spaces.
Comment: @RoopamSinha: In general, any linear operator on a separable Hilbert space admits a matrix representation. Regarding spin systems: it seems there is a bit of confusion, where you're mixing the bases of the states with the representation of the Hamiltonian. The state space in the spin system is a finite tensor product of finite-dimensional Hilbert spaces, which is ultimately a finite dimensional vector space. Thus any linear operator acting on it will admit a (finite) matrix representation.
Comment: @joshphysics: Furthermore, every separable Hilbert space is isomorphic to $\ell^2(\mathbb{Z})$. Thus every QM Hamiltonian is unitarily equivalent to a Hamiltonian acting on $\ell^2(\mathbb{Z})$, where it admits a (rather easily constructed) Matrix representation.


Is it a good practice to make sudo ask for root password in a single-user system?

Question: I have a server where I am the only normal user and I need to have password-based authentication enabled for SSH. I have configured iptables with recent module which throttles SSH connections and root logins over SSH are disabled. However, let's say that intruder is able to brute-force my SSH password. This means that once he has logged in as a normal user he can execute privileged commands using sudo with the same password. Am I correct that in such scenario it makes sense to configure sudo in a way that it asks for root password?
Comment: Did this answer your question?
Answer: Yes, you should.
In a brute force attack against the raw hash, sudo won't help you. However, you should be aware that in other attacking methods, sudo is able to offer some protection.
If, for example, an attacker is able to break into your machine with an exploit, he does not know the password. Potentially delaying or stopping an attack as the attacker does not have the proper privileges to carry out system commands.
However, sudo should be a last line of defense. Once an attacker is in, they are in. Privilege escalation is a commonly practiced strategy. An experienced attacker should be prepared to escalate privileges.
Comment: You are correct. Since `su` logs you into the root account, you might as well you su instead. Let me know if you have any more questions.
Comment: So, the answer is:  "yes" you should.
Comment: @GavinYouker Thanks! However, when I think about it, is there a point to use `sudo` in this scenario in the first place? If I configure `sudo` to use root password, then I might use `su` instead?
Comment: @Martin If I have answered your question *correctly* please mark it as the right answer for future viewers, thank you.


Tree help with identification

Question: Can anyone tell me what type of tree this is please? ](https://i.stack.imgur.com/vjl6m.jpg)
Comment: How big is the tree?
Comment: Big! About 20ft?
Comment: In which region/continent you found such tree?
Comment: Giacomo it is in Scotland :)
Answer: I do not agree with @ColinBeckingham answer, but I agree with the family.
I think it is a Sorbus (whitebeam). Maybe the Sorbus latifolia, or a Sorbus aria. Sorbus has also hybrids.
Comment: I think you're right @Shona, you could check by feeling the leaves, Wikipedia says:

"The leaves are five to ten centimetres long and broad (rarely, up to 20 cm long and 12 cm broad), but, most typically, the leaves are approximately as broad as they are long. (Latifolia is the Latin word for 'broad-leaved'.) They are **green above, downy with greyish-white hairs beneath**, with six to ten small triangular teeth along each margin."
Comment: I shall take one of the leaves off and check when I can @MaxSpencer thank you!
Comment: @MaxSpencer .. the leaves are very soft underside, like velvet. The height of the tree us between 25 - 30 ft and it has no thorns
Answer: Well it appears to be a Hawthorn or Crataegus, but which one is harder to say. If we look at Hawthorn leaves (say with a Google image search) the viewer will find there is a great variety of shapes, and this one fits with those which are less deeply lobed than most of them.
Given the size of the fruit and the size of the tree I would guess C. pinnatifida or Chinese Mountain Hawthorn. See if you can find thorns on the tree; if so, if there are just a few short thorns then this is a strong confirmation of C. pinnatifida, but if there are lots of brutally sharp thorns then that leans towards a more common Hawthorn.
Comment: Thanks for that Colin..its not my tree but my fathers so I'll have a look the.next time i'm along there
Comment: I think it is a Sorbus. Check my answer. What do you think?
Answer: Your tree is a Swedish Whitebeam, Sorbus intermedia, which is native to Sweden(!), and ranges from Denmark to Latvia and Poland, and more recently Scotland, Wales, England & Ireland. The illustration clearly shows the upper side of a typical characteristic leaf, which have hairlets on their undersides.
The Swedish Whitebeam is closely related to several other Whitebeam species, and can be distinguished from the Vosges Whitebeam/Mougeot's Whitebeam, Sorbus mougeotii, by the Swedish Whitebeam's characteristic leaf edges and generally more orangish fruit. The undersides of Whitebeam leaves typically are grayish-whitish with whitish veins, and gusts of wind can result in noteable sudden difference in the appearance of the trees, from which the name: 'Whitebeam'.
Swedish Whitebeams are fairly stout trees, typically grow to about 10m height, sometimes to 18+m, and have 70-200+cm  diameter trunks. They are also fairly hardy trees. Their fruit is used in baking, and to make jelly, though Swedish Whitebeams are often planted as ornamentals.

Tree help with identification


How are the earnings of a Crypto Interest Account taxed?

Question: I have some bitcoin in an interest saving account. I am not sure if I have to consider the interest earned as Tax on Savings Interests (which does not mention anything related to crypto) or Cryptoassets: tax for individuals (which does not mention anything related to interests).
Comment: How are you holding bitcoin in a savings account?  Do you have more information on this?  Do you own bitcoin, or a savings fund invested in Bitcoin?
Comment: Apart from holding them in cold storage, I also have some Bitcoin, USDC and ETH in interest savings accounts since around one year ago. The interest is paid monthly in each crypto. The service is called Blockfi.
Answer: Currently the key piece of information you would be interested in is here: https://www.gov.uk/government/publications/tax-on-cryptoassets/cryptoassets-for-individuals
You confused me about "savings account" but I see what you are inferring.   You have an online account with cryptocurrency that pays interest.   However as you will see in the link, since the UK government does NOT view bitcoin as currency, this is not a savings account in the traditional view, therefore Tax on savings interest is irrelevant here.
Therefore you are looking at capital gains tax (as mentioned in the link to the government information page) on disposal.  Just view the in interest as having a cost of zero (although will average on disposal to whatever you paid for the rest).   This is similar to having crypto in a staking wallet (which earns interest).  This is exactly the same as how you would deal with the disposal on other stored crypto (such as what you have in cold storage)
If you are not disposing of them in the tax year, you will not have capital gains to declare, as you will only pay tax on disposal.   The gains will count towards your capital gains limit - so for 2019-20 tax year, if you gain less than 20K profit (including all gains, e.g. from stock disposal, selling second property etc), you will not owe any tax.
Comment: So sorry for the confusion. As you can imagine, it wasn't very clear to me! Thanks so much for your comment - very helpful indeed. You are a master! So I will have to worry about this when disposal.
Just one observation, is not the capital gains allowance for 2019-20 tax year £12k instead of £20k as per https://www.gov.uk/capital-gains-tax/allowances ?


Power BI matrix to show unrelated table columns

Question: I have a matrix in Power BI that shows sales and stock information from two tables, by year and region. Third table that contains article IDs and is linked to both tables and used as a slicer. I have also created another table with years and linked it to both tables as well so I could get both sales and stock information on the same matrix.
Sales table contains sales and qty by year and region, while stock table contains stock information only by year.
As a consequence, my matrix shows same stock information for all regions but I would like it to only show it for regions where we have sales (only Asia in example below). Since I do not have stock information by region in stock table but only by year, is there a way to make stock appear in matrix only in regions where we have sales data?
Answer: I was able to solve this using TREATAS function in DAX to connect two unrelated tables.


User can logon domain pc with locked account

Question: Windows 2008r2 domain. windows 7 client.
After locking user domain account, user can login domain pc with locked account once, at the same time user have no access to netwrok shares, only local files.
I expected that after locking domain account user cann`t login domain pc
Comment: This is probably cached credentials.  http://technet.microsoft.com/en-us/library/hh994565.aspx
Answer: This is due to the client computer caching the user's credentials.  With this setting enabled, the client computer stores X number of logons locally, and when the user tries to logon again, client computer checks the password against a locally-stored hash, rather than contacting a domain controller.
If you want to disable local credential caching, you can (and it's even advised as a best practice by Microsoft), but you better be sure you know the local Administrator credentials, and be aware of the implications of not caching credentials - particularly, users won't be able to logon to their computers unless they're already connected to a network where they can access a domain controller.  So, for example, if you have remote or traveling employees who need to access the corporate network with a VPN client, you might want to leave credential caching in place for those users' machines.
Comment: I thought that the cache is used only if there is no connection with the domain controller.
Comment: I can not disable the caching because we have remote vpn network segments. Maybe you have a best practices how to block user accounts?
Comment: @Dreddko The way we do it (and the way I've always seen it done, FWIW) is to apply a different policy to the "Remote"/VPN users.  Current workplace puts them in a different OU that has inheritance blocked (and contains VPN-specific policies), but anything that lets you filter GPOs is just fine.


Electrical resistence between two different terminals

Question: I have to calculate the resistance R_AB, R_AC and R_CD. But I'm confused because there are two different terminal, one on the left and one on the right. Can someone give me a hint how to solve this?
Answer: If you were to draw out the circuit with just the terminals mentioned you would get this.

The wood should now be separated from the trees.
Comment: Hi thx for the pictures :) I understand it now. It was simple, but sometimes your thoughts need a push to thing about it differently.
Answer: Not sure why are you confused. For R_AB there are only two terminals, both on the left. For R_AC one is on the left and one on the right. For R_CD both are on the right.
You should just ignore unused terminals and solve the schematics using the rules of parallel and series resistors. Or Kirchgoff / Ohm laws.
For example for R_AB the C is ignored, you can erase it to the closest junction (but leave the resistors 10 and 10 connected). For R_AC you erase both B and C and then erase the 30 resistor since its bottom terminal is not connected anywhere.


using jQuery Cycle by Malsup with WordPress Page and Gallery

Question: I would like to modify a WP Gallery to use the jquery cycle plugin by malsup.  I know this is possible but would like to know best practice for this, if anything just pulling out the url for each image should give me enough to work with.  Please advise on best practice for this. Note I do not want to use a plugin and would like to build this site on WP Core.
Comment: Someone has already integrated this with the [NextGen Gallery](http://wordpress.org/extend/plugins/nextgen-gallery/) and [JJ NextGen JQuery Cycle](http://wordpress.org/extend/plugins/jj-nextgen-jquery-cycle/)
Comment: I meant that I do not want to use a WP plugin.  I want to cycle through the images in the WP Gallery tag feature and wrap those images in jQuery cycle.
Answer: What your asking for has the basic functionality of a plugin, so saying you don't want to use a plugin doesn't make much sense.
If you do for some reason want to write your own , using any jquery or JavaScript is relatively straightforward, you enqueue the script where you want it, then wrap whatever data your using in the javascript tags ( usually a div class or id ). This is a very basic example.
http://codex.wordpress.org/Function_Reference/wp_enqueue_script
 wp_register_script( 'jquery_cycle_name','http://path-to-your-cycle.js');
 wp_enqueue_script( 'jquery_cycle_name' );

The javascript:
jQuery(document).ready(function($) {
    $('#featured-works').cycle('fade');
});

Your template or whatever you wrap your info in, typically you want this in a loop to go through several images/posts or content.

 images, etc, go here

Comment: Thank you for your reply Wyck, My meaning plugin meant I did not want to rely on a WP plugin, I would like to accomplish this by using WordPress' built in WP Gallery.  I am a front-end developer who spends some time in WordPress but not that often, so making the JS work is not an issue. I would like the client to be able to edit the cycle on the respective page by just editing the gallery within that page.
Comment: Use the example above, to loop through a posts images you can wrap the javascript div with something like `get_children`, http://codex.wordpress.org/Function_Reference/get_children


Is there a translation of Kronecker's original work on adjoining a root of a polynomial to a field?

Question: I would be interested in reading how Kronecker formally approached this construction, using the mathematical ideas of his time, and possibly some insight as to what he considered its philosophical implications to be. I am referring specifically to the construction which, in modern terminology, adjoins a root of an irreducible polynomial $f(x) \in F[x]$ to $F$ by constructing the quotient $F[x]/(f(x)) $, where $(f(x))$ is the ideal of $F[x]$ generated by $f(x)$.
Comment: A quick skim through section 12.3, "Kronecker", of David A. Cox, *Galois Theory* (2nd ed. 2012) suggests that this could be quite a big subject! For details, Cox refers to a number of essays by H. M. Edwards. Perhaps these could be of some help, even if there is no English translation of *Ein Fundamentalsatz der allgemeinen Arithmetik* (1887, in *Werke,* vol. III, pp. 209--240), or earlier papers on which that one presumably depends.
Answer: At least as a placeholder answer: it is my impression that that idea would have been extremely novel for its time, since there were not abstract ideas of rings and ideals and such. On the other hand, the seemingly-tangible idea that a (reasonable) field extension of $\mathbb Q$ is obtained by adjoining suitable complex numbers (which we believe exist, etc.), had serious limitations of scale.
These limitations can be seen in A. Weil's "Foundations of Alg Geom", in the 1940s, which needed algebraically closed field extensions of uncountable transcendence degree. (True, the seeming need for "Grothendieck universes" in the most-cavalier development of modern algebraic geometry has some serious foundational stuff going on, too.)
But, no, I don't know of a translation.
Comment: It probably is like Cauchy's earlier proposed definition of $\mathbf C$ as congruence classes of real polynomials modulo $x^2+1$. He would not have used cosets, but just remainders with addition and (especially) multiplication done modulo $x^2+1$. Galois probably did something similar to build finite fields of nonprime order. There must be some specific paper of Kronecker where the idea was presented.
Comment: Thank you for your answer! [In this answer](https://hsm.stackexchange.com/questions/2250/why-did-kronecker-develop-the-adjoining-a-root-construction?rq=1), someone explained that Kronecker didn't like Dedekind's notion of ideals so I imagine his construction was very different than what we'd see in a modern algebra book. This is partly why I'd like to see his original construction.
Comment: @PrimeNumbers this was proposed by Cauchy in 1847. See page 63 (Chapter 3) of the book "Numbers" by Ebbinghaus et al.
Comment: @KCd, I wasn't aware that Cauchy had proposed such an idea! Do you know where I could read some more about that?


Can a certified mechanic ground my airplane?

Question: The courtesy (under-wing) lighting and the rear seat overhead map light were on the same switch. I didn't like having the bright outside light on while my passenger read his magazine, so I separated the lights to two different switches.  What will happen when this is discovered during my next annual? And can a certified mechanic ground my airplane for it?
Comment: When you say you separated the switch to two different switches, was the second switch in use for something else, or was it a blank switch?
Comment: Welcome to aviation.SE! If I understand correctly, you have two questions here: does a mechanic have the authority to ground your aircraft; and does your wiring change require a mechanic's approval? Is that accurate?
Comment: Is it worth differentiating between taking action to "ground" your airplane vs refusing to approve by not signing off the annual inspection?  Because in my mind they are distinctly different things.
Comment: @Pondlife My guess is that any wiring change not in accordance with the official aircraft manuals should never have the approval of a qualified mechanic and therefore lead to the aircraft failing its annual until corrected/reverted.
Comment: @jwenting Yes, that makes sense; I've mentioned it at the end of my answer.
Answer: The short answer is that a mechanic can't ground a plane. There are lots of discussions online about this, and the typical scenario seems to be that a mechanic "refuses to sign off an annual" or something similar. (There are other scenarios too, where the mechanic refuses to return the aircraft and/or logbooks to the owner because of a dispute over payment or work performed, but that's a legal issue, not an aviation one.)

AOPA has two useful articles (here, here) on this topic, written by Mike Busch (a well known A&P and author). He says:

Who can ground an aircraft?
FAR 91.7 forbids a PIC from flying an aircraft that is unairworthy,
although FAR 21.197 (Special Flight Permits) allows the FAA to grant
special dispensation to fly an unairworthy aircraft (usually for
repositioning purposes). There is no FAR that empowers a mechanic to
ground an aircraft. Mechanics are not the safety police.

When it comes to signing off on maintenance, there are two cases: required inspections (e.g. annuals), and general maintenance (e.g. an oil change). Required inspections are governed by 14 CFR 43.11.
43.11(a)(4) says:

[...] if the aircraft is found to be airworthy and approved for return
to service, the following or a similarly worded statement—"I certify
that this aircraft has been inspected in accordance with (insert type)
inspection and was determined to be in airworthy condition."

43.11(a)(5) says:

[...] if the aircraft is not approved for return to service because of
needed maintenance, noncompliance with applicable specifications,
airworthiness directives, or other approved data, the following or a
similarly worded statement—"I certify that this aircraft has been
inspected in accordance with (insert type) inspection and a list of
discrepancies and unairworthy items dated (date) has been provided for
the aircraft owner or operator."

In other words, even if the mechanic finds that the aircraft isn't airworthy, they're still required to make and sign a logbook entry to document that. The key point that Mike Busch makes is that what happens next is up to the owner, not the mechanic:

The owner must correct those discrepancies before the aircraft may
flown. He is free to have them corrected by any mechanic he chooses.
There's no need for the inspecting mechanic to look at the aircraft
again. The next annual comes due in 12 calendar months.

The owner might ask the same mechanic who did the inspection to make repairs, or a different mechanic at the same airport. Or they might ask the FAA for a ferry permit to move the aircraft to another location for maintenance. Or they might just fly the aircraft anyway, knowing it isn't airworthy.
As for other maintenance that isn't a required inspection, 43.9(a)(4) says (emphasis mine):

If the work performed on the aircraft, airframe, aircraft engine,
propeller, appliance, or component part has been performed
satisfactorily, the signature, certificate number, and kind of
certificate held by the person approving the work. The signature
constitutes the approval for return to service only for the work
performed.

Here's Mike Busch's commentary on that:

Those two sentences bear careful reading. The first sentence makes it
explicitly clear that a mechanic's signature on a 43.9 logbook entry
does not signify anything about the airworthiness of the aircraft. It
signifies only that the work the mechanic completed was performed
satisfactorily. [...]
The second sentence makes it clear that the mechanic's signature does
not constitute an approval for return to service for the entire
aircraft (the way an annual inspection signoff does). It constitutes
approval only for the work the mechanic performed.

So coming back to your specific wiring scenario, if the mechanic performs a required inspection and determines that the change makes the aircraft unairworthy, they would document it as a discrepancy per 43.11. That means the aircraft is not airworthy, but how to make it airworthy is your decision, not the mechanic's decision.
Finally, if you're not sure how a mechanic would react to your wiring change you should probably find out. It's possible that the aircraft is already unairworthy, but that depends on a lot of details: type of aircraft, certified vs experimental, any applicable ADs etc.
Comment: I would say that adding a switch counts as a minor alteration and only needs an A&P's signature. If it isn't in the major alterations list in Appendix A, it's a minor by definition.  I don't think adding a switch meets the criteria.  The AI will see the change, go and check and see of an A&P made a log entry, and if not just inspect it and sign it off if satisfied with the work (and charging for it), or add it as a discrepancy if not.  The biggest problem here is the AI now knows the owner likes to do home projects on the sly and will be wondering what other surprises are hidden in the plane.
Comment: and of course after the fixes are done, another inspection is needed to certify the aircraft as airworthy. So it's best to have things you know to be out of spec fixed BEFORE you have the aircraft inspected.
Answer: Terrible misinformation on here. The truth is YES an A&P automatically grounds a plane when and if he does not release it as airworthy. If he signs log book that the plane is not airworthy THEN It is illegal for any pilot or owner to fly any plane that is not airworthy. A plane with a log entry it is not airworthy is illegal to fly. It is effectively grounded. NOW if the A&P has not released the plane as airworthy the owner now must get FSDO permission to fly that plane in a ferry permit or have plane fixed where it is some way that is legal. . In addition, if for any reason the A&P suspects that the pilot or owner may fly the plane even after it is found not airworthy, he can contact the FSDO and have a PI do a ramp inspection and ground the plane permanently on the spot.  SO when can a A&P write a determination it is not airworthy? After any repair or maintenance where they have identified a non airworthy condition of the plane the owner does not want fixed. It must then be recorded in log book MAKING the plane at that instant, grounded for all intense purposes, since it is illegal for anyone to fly it without being airworthy. The owner pilot will need FSDO permission to ferry or fix plane another way that is legal . NOW you have the real truth. It is NOT up to the pilot if he wants to fly a plane a A&P has determined is not airworthy. IT is up to FSDO and it is illegal to fly unless they give a ferry permit, or unless the problem has been corrected and another A&P signs off it has been corrected, followed by a I/A return to service. Because only a I/A can sign off any discrepancy that has been repaired as passing inspection and able to return to service, AFTER it was found to have been not airworthy by a A&P. Another A&P repair alone can not return a plane to service after a non airworthy discrepancy has been noted in the log by a A&P. A&P can only return to service 100hr inspections and regular maintenance of planes that are still airworthy, withing the annual time period of a planes Last 1 yr airworthiness authorization. by doing so ALL A&Ps do is prove a plane is still airworthy within the annual period. . They can not return to service any repaired discrepancies on a plane that is already documented as not airworthy. Once a plane is stated as not airworthy, only a I/A can return to service, or a DER or the FAA. Period.
Comment: Hi Joseph, and welcome to Aviation.SE. What you've posted is a bit of a wall of text; please add paragraph breaks to make it more easily readable.  Also, you make a lot of statements, but the current text doesn't provide any sources or references, making it all "somebody on the internet said that..." at this point. While I suspect that most or all of your statements ***can*** be supported by the applicable FARs, somebody who's looking for an authoritative answer doesn't have much to work from at this point from your post. It would help if you add links to the relevant regulations.
Comment: Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer).


How do I calculate x, y, z velocity given two rotation angles and a speed?

Question: Another way of saying this question: How do I find the length, width and height of a cuboid given it's diagonal length and 2 rotational angles.
This is for a 3d game where the user can change up/down rotation (UP and DOWN arrow keys), left/right rotation (LEFT and RIGHT arrow keys) and the object can accelerated and reverse (Q and w). Each frame, the objects x, y, z gets updated according to it's current speed and up/down and left/right rotation.
Answer: If alpha is the left/right angle and beta is the up/down angle, then
v.x = speed * sin (alpha) * cos(beta)
v.y = speed * sin (beta)
v.z = speed * cos (alpha) * cos(beta)

Assuming, that no rotation will return the direction (0, 0, 1)
Answer: I'm assuming that this cuboid is measured using a static frame of reference, where the diagonal starts at the origin and extends to some other point.  If not, this question has no definitive answer, as a diagonal length alone can not determine the width, height and length of some arbitrary cuboid, as there are an infinite number of cuboids that could have the same diagonal.
It sounds like what you're using is a spherical coordinate system: http://en.wikipedia.org/wiki/Spherical_coordinate_system#Cartesian_coordinates
From the article:
x = r sin θ cos φ
y = r sin θ sin φ
z = r cos θ

r is your diagonal length.  You'll have to determine θ and φ based on your rotation angles; they may not be proper inclination and azimuth angles.  See the article for details on how these angles are defined in spherical coordinates.
Comment: Awesome - sounds like the same equation as the other answer. I'll read up on the spherical coordinates system to understand it better. Thanks  .


The use of comma between adjectives

Question: I've stumbled upon this piece of text from ''Stormy Weather'' by Carl Hiaasen and I'm trying to understand why in the sentence ''On paper he seemed an ideal candidate, a bold fresh voice in a cynical age.'', there's no comma between ''bold'' and ''fresh''. Could someone explain?
Comment: It is common to have sequential adjectives not separated by commas.
Answer: Whether a comma is required depends on the intended meaning.
Inserting the comma in "bold, fresh voice" would give 'coordinated' modification, so "voice" is modified by a coordination of adjectives, giving the meaning "voice that is both bold and fresh".
By contrast, omitting the comma in "bold fresh voice" would give 'stacked' modification where there are two layers of modification: "voice" is modified by "fresh" to form the nominal "fresh voice" and this in turn is modified by "bold", allowing a somewhat different interpretation  - "voice that is bold by the standards applicable to fresh ones".
In the example you gave, the author presumably omitted the comma intentionally, so we interpret it as stacked modification. He could of course have simply got it wrong and really intended it to be coordination, but omitted the comma in error. Who knows?

The use of comma between adjectives


How do we promote our site?

Question: Currently, we have a strong user base with a very high number of Stack Exchange moderators. However this site is not intended just for covering moderation issues relating to the Stack Exchange network. How can we find and attract moderators, community managers and interested parties from other corners of the web, and how can we make them feel valued in what is currently a site with an overwhelming SE bias?
Comment: some advice from the SO blog: http://blog.stackoverflow.com/2010/08/a-recipe-to-promote-your-site/
Answer: It's going to be tricky in many instances. Particularly because trying to advertise / promote a site is going to border on spam in many instances.
One possible route to take is that many sites with moderation have a 'contact the mods' option. (Either PM'ing them or other more global methods) so perhaps - and I would suggest only doing so if you're a frequent user of such sites - is you could use that option to contact site mods to suggest they visit.
I am not a moderator on any site other than SE though, so I'm not sure how I'd feel about being directly contacted in such a way regardless of how useful it is. I've no idea how much spam comes direct to moderators in such a manner anyway, so it could just get dismissed and / or risk you getting suspended from such sites. So YMMV, as they say.
Answer: We could definitely leverage SE's search engine presence as a sort of "self-advertising". By asking really good questions that a lot of moderators have, we can attract people who are doing their own research on how to deal with tricky issues.

How do we promote our site?


if i only record my own voice in a telephone conversation can i legally use it

Question: can I record a conversation with my phone when I am speaking to someone on the call. the only voice recorded is mine , and the other persons voice is not recorded. can I legal use this in court
Comment: This would be to establish that under some unknown circumstance (and time) you said particular words out loud, possibly to no one ?
Comment: In the courts of what country / state?  Laws vary around the world.  Please clarify your question and add a tag corresponding to your jurisdiction.
Comment: @GeorgeWhite if he has call records from the same time it can corroborate his story
Answer: There are laws against recording conversations, which were passed in response to a government practice of listening in on conversations between people. The weaker form of such laws says that at least one party to the conversation must consent to the recording. The stronger law, operative in Washington, California and about a dozen other states, is that all parties to the conversation must consent. The intent behind these laws is to require consent or knowledge of one or all of the people being recorded. What is not entirely clear (in all-party states) is what constitutes a communication, and what a party is, given the wording of the statutes.
Washington law is an example of an all-party consent law, which states a prohibition against recording without "first obtaining the consent of all the participants in the communication". The law does not state this in terms of "the consent of those persons who are recorded". It is unclear whether a person who could in principle hear and be heard (e.g. in a room full of people, with the phone on speaker) are "participants" since the term is not defined. California law refers to "the consent of all parties to a confidential communication", again with no specific mention of people who do not speak, and also no exception made for "parties" who are not actually recorded.
The court in CA has determined that a confidential communication is one in which the parties have a reasonable expectation that no one is listening in. Suppose that A and B are having a quiet conversation in public, and they do not expect that anyone else can hear them, but there are other people nearby. This is a confidential conversation, recording of which requires permission of all parties. A and B can agree to record the conversation. A common sense understanding of "party" would find that if C can actually hear the conversation, he is still not a party to the conversation, therefore he does not have veto power over A & B recording their conversation. To the best of my knowledge, the courts have not ruled on what exactly constitutes a "party" or "participant". Nor have they ruled on what constitutes a "communication". It is possible, but legally untested, that you can record yourself (e.g. with a recorder in the room with you) talking into a phone, where there is some other person on the other end of the line: you're just recording your monologue.
However, the legal utility of doing this is really not obvious, and you really need to hire an attorney who is versed in your jurisdictions case law on the topic, before sticking your head in the noose.


What does "all malt" mean?

Question: Pork Slap beer indicates that it's "all malt" in the way that implies an official distinction.  What does "all malt" indicate, assuming there's a standard requirement to use the term accurately.
Comment: Is this the first [freehand circle](http://meta.stackexchange.com/a/19775/188984) on this site?
Comment: In the case of Japan, alcoholic beverages are taxed depending on their malt content which has resulted in a slew of beer-like beverages with varying degrees of less malt, or even no malt. These are known here as 発泡酒 "happoushu" rather than "beer". One result of this is that all malt beers are now a premium product so proudly declare their maltiness in their packaging and advertising much like on the can you've pictured.
Answer: All malt beer is made entirely from mashed barley malt and without the addition of adjuncts, sugars or additional fermentables.
From an expert of a widely known brand beer producer in my country (Turkey), beers here must be at least 60% malt (This may be different in other countries). The rest are adjuncts, like sugar or corn or rice etc. Using adjuncts is also for decreasing the cost or to lighten the color of beer.
Comment: Where does 60% come from?  I've never heard that specification before.  Is that just with adjuncts or all fermentables (e.g., honey)?
Comment: May be I must make it clear. That knowledge is from a local expert of a big brand in my country. Probably it may be changed. You are right, it is better to make it clear.
Answer: Many large brewers, like AB InBev's famous Budweiser line, Miller-Coors' flagship brands and other Standard American Lagers (BJCP Style 1B) use adjunct grains in their grain bill.

Aroma: Little to no malt aroma, although it can be grainy, sweet or corn-like if present. Hop aroma may range from none to a light, spicy or floral hop presence. Low levels of yeast character (green apples, DMS, or fruitiness) are optional but acceptable. No diacetyl.
Appearance: Very pale straw to medium yellow color. White, frothy head
  seldom persists. Very clear.
Flavor: Crisp and dry flavor with some low levels of grainy or
  corn-like sweetness. Hop flavor ranges from none to low levels. Hop
  bitterness at low to medium-low level. Balance may vary from slightly
  malty to slightly bitter, but is relatively close to even. High levels
  of carbonation may provide a slight acidity or dry "sting." No
  diacetyl. No fruitiness.
Mouthfeel: Light body from use of a high percentage of adjuncts such
  as rice or corn. Very highly carbonated with slight carbonic bite on
  the tongue.
Overall Impression: Very refreshing and thirst quenching.
Comments: Strong flavors are a fault. An international style including
  the standard mass-market lager from most countries.
Ingredients: Two- or six-row barley with high percentage (up to 40%)
  of rice or corn as adjuncts.

Some beers bill themselves as a "Pale Ale", like Rolling Rock also use adjuncts, like rice.  This notation is designed to set them apart from those other beers.  It should be noted that the BJCP guidelines for a Pale Ale are:

Aroma: Usually moderate to strong hop aroma from dry hopping or late
  kettle additions of American hop varieties. A citrusy hop character is
  very common, but not required. Low to moderate maltiness supports the
  hop presentation, and may optionally show small amounts of specialty
  malt character (bready, toasty, biscuity). Fruity esters vary from
  moderate to none. No diacetyl. Dry hopping (if used) may add grassy
  notes, although this character should not be excessive.
Appearance: Pale golden to deep amber. Moderately large white to
  off-white head with good retention. Generally quite clear, although
  dry-hopped versions may be slightly hazy.
Flavor: Usually a moderate to high hop flavor, often showing a citrusy
  American hop character (although other hop varieties may be used). Low
  to moderately high clean malt character supports the hop presentation,
  and may optionally show small amounts of specialty malt character
  (bready, toasty, biscuity). The balance is typically towards the late
  hops and bitterness, but the malt presence can be substantial. Caramel
  flavors are usually restrained or absent. Fruity esters can be
  moderate to none. Moderate to high hop bitterness with a medium to dry
  finish. Hop flavor and bitterness often lingers into the finish. No
  diacetyl. Dry hopping (if used) may add grassy notes, although this
  character should not be excessive.
Mouthfeel: Medium-light to medium body. Carbonation moderate to high.
  Overall smooth finish without astringency often associated with high
  hopping rates.
Overall Impression: Refreshing and hoppy, yet with sufficient
  supporting malt.
Comments: There is some overlap in color between American pale ale and
  American amber ale. The American pale ale will generally be cleaner,
  have a less caramelly malt profile, less body, and often more
  finishing hops.
History: An American adaptation of English pale ale, reflecting
  indigenous ingredients (hops, malt, yeast, and water). Often lighter
  in color, cleaner in fermentation by-products, and having less caramel
  flavors than English counterparts.
Ingredients: Pale ale malt, typically American two-row. American hops,
  often but not always ones with a citrusy character. American ale
  yeast. Water can vary in sulfate content, but carbonate content should
  be relatively low. Specialty grains may add character and complexity,
  but generally make up a relatively small portion of the grist. Grains
  that add malt flavor and richness, light sweetness, and toasty or
  bready notes are often used (along with late hops) to differentiate
  brands.
Comment: Rolling Rock doesn't bill itself as a Pale Ale... it is an American Standard Lager and is often cited for its corn flavor.
Comment: Just FYI Rolling Rock is not a pale ale; they self-describe the beer as an "xtra pale lager," and in regards to BJCP styles most closely fits 1A - Lite American Lager although certain elements of the beer would fit in 1B - Standard American Lager.
Answer: The only fermentable sugars are from malt, 2 row North American barley and English crystal malt in the case of this beer. So as others have stated no adjuncts are added. This beer does add ginger for flavoring

What does "all malt" mean?


single command to gather mac addresses of connected devices to switch

Question: I've connected multiple PCs to a 2960 switch and then entered privilege mode and entered : show mac-address-table but the table is empty. Then I pinged the broadcast address from one of the PCs: ping 192.168.1.255 and used the previous command on the switch once again and the mac address table lists all the PCs' mac addresses, I wonder if there is a shorter way? i.e. a command on switch to gather the mac addresses of the connected devices to its ports without the need to the pinging step? Thanks.
Comment: I'd also send a ping to `ff02::1` in case there are devices which don't respond to `192.168.1.255`. Of course it still won't guarantee to reach all devices, and there really isn't any way to force an unknown device to send a packet.
Answer: EDIT:
To actually answer the question: show mac-address-table or show mac address-table (depending on platform and software generation) is the single command to see the MAC address table on a Cisco Switch like the 2960. The fact that the table comes up empty is very probably correct.
Here's why:
MAC address tables (sometimes referred to as CAM tables) are usually dynamic, and their entries are aged out after a given timeout, usually 300 seconds.
An entry is added as soon as an Ethernet frame arrives on a switch port. It's source MAC address is kept and is added to the CAM table and its aging timer starts to decrement.
If connected devices stay silent for more than 300 sec (or the given CAM table aging value), their MAC addresses are removed from the CAM table.
If another device needs to talk to such a dormant peer, the switch will have to perform "unknown unicast flooding" and send the given Ethernet frame out of all ports (more precisely: all active/forwarding ports of the given VLAN). As soon as the device of interest responds with an Ethernet frame, the CAM table is (re)populated instantly with a new entry.
There can be more advanced setups with sticky or static CAM table entries, but that's another story.
This being said...
IF a constantly populated CAM table is a requirement, AND IF  the connected devices have no need to be allowed to "sleep" for longer periods of time (for example to save energy), AND IF the scope of interesting devices/table entries covers IPv4 enabled devices, there is one trick that can help a lot without requiring a lot of advanced config:
Many routers (CEF enabled Cisco router definitely do it) do active maintenance of their ARP cache, but have a default ARP timeout of 4hours. By lowering their  ARP timeout to some value lower than 300sec (which does little to no harm), the router will re-query the entries in its ARP cache, shortly before they expire. That will in turn trigger a response from the devices, and these ARP replies  then keep the switch's CAM tables populated.
Answer: When network setup is new , initially mac -address table in switch will be empty because there are no request received by switch to forward frames towards destination no ARP flooding and no broadcast traffic to create mac-address table in switch . When a request reaches towards switch it's associated mac-address table is created .
To get full mac-address table connected on switch in some way traffic has to be initiated from source or towards destination so that mac -address table is built in switch .