Chainring sizes for 11 speed cassette

Question: I have an 11 speed cassette 11-32 teeth. I am running a 52 teeth chainring on the front. What would be a good recommended smaller chainring for the front?  It needs to be big enough to take up the slack of the chain when i am on the smallest cog at the back.
Comment: The job of taking up the slack is the rear derailleur.  Note that your choices are limited by what the front derailleur can shift and what the rear derailleur has capacity for. Also, running in small/small is usually not a good idea except for maintenance.
Comment: Could you clarify your question? What do you want to use the bike for? Are you running only a 52-tooth at the moment? Are you asking about a single chainring that's smaller than your current 52-tooth, or for a double chainring that would be 52-and-something?
Comment: I understand that you have a single 52 ring  or a double in the front?
Comment: If you're asking for an additional ring to your 52, it would be a 36. Or you could change both to a 50/34 which would both work together with an 11-32 and a medium cage RD possibly without removing a link from your chain.
Answer: As was mentioned in the comments, this question will depend on what derailleur you are using both front and rear (since they have a rated capacity). Too large a difference and the front derailleur will not shift well, but you also have to make sure the the total difference between large-large and small-small is within the range of the rear derailleur so that it takes up the slack and does not overextend. The specifications for your derailleur should have these numbers listed and then you can pick an appropriate sized ring to fit your crank from there.
Answer: You'll generally want to get the smallest inner chainring possible, in order to maximize the spread of gears. The actual size of that chainring will be determined by your crank's BCD (bolt-circle diameter). It's impossible to say what size your BCD is, although with a stock 52t big ring I would guess that it's a road standard size, 130mm. This means your smallest available inner ring is 39-tooth. 52/39 is a modern standard combination, and 52/42 is an older standard; either will work.
I wouldn't worry too much about your derailer capacity and chain slack. If your rear derailer can accommodate a 32 tooth cog, it must have a medium or long cage, both of which are capable of "wrapping" plenty of chain. The only instance in which chain slack becomes an issue is when combining the inner small chainring with a small cog on the cassette. This combination is horrid for your drivetrain, and ought to be avoided at all times.
If you are worried about chain slack because of dropping a chain, that is a separate issue, largely unrelated to derailer/chainring compatability.
1) dropped chains are a fact of life. get used to "picking up" a chain using the front shifter to avoid having to get off the bike.
2) if it's a mechanical problem, your limit screws may be improperly set.
3) don't shift under heavy load. if you shift into a low gear while you're already climbing the hill, you're doing it wrong and you're breaking your parts. shift BEFORE you need the gear you want to be in.
sorry for the pithy attitude, i've had a few beers and am striving for clarity.
edit: if your cranks end up being 110bcd (compact BCD), you can go pretty low on your inner ring. You could even do a 52/34 (I do!), but you must accept tricky front shifting.
Comment: Re: 'dropped chains are a fact of life'. Maybe for you. No rider with a modern drivetrain should have to put up with that.
Comment: @ArgentiApparatus A dropped chain is my bike's way of telling me, "Erhum, could you adjust me please?"
Comment: Dropped chains are a fact of life, especially when racing. You can have a perfectly adjusted group and if you happen to hit that bump in the road at the right moment that you down shift, your chain's going to hop off the crank. Instead of complaining about your expensive parts not working, learn to deal with that situation when it occurs. Also, there are a lot of lower end groups with shoddy tolerances that require a trade-off between tight limit screws and constant chain rub. If the customer complains about the noise, I tell them what I can do to fix it and the risk that incurs.

Chainring sizes for 11 speed cassette


What time of the year do government agencies in the United States typically hand out funding?

Question: Are there any specific seasons, months, weeks which have shown to be the time at which the majority of funding is handed out by Government agencies in the US? Are there any reliable studies that have answered questions around this topic in the past?
Comment: @BrianBack - that's still probably too vague to answer; some agencies have year-to-year funding (and so don't know how much they have until Congress passes some form of spending bill) while others have guaranteed amounts every year, regardless of Congress's (in)ability to pass such bills. If you could narrow it down even a bit further it would likely help.
Comment: Many programs at the NSF have application deadlines on a specific yearly (or twice yearly) schedule, with awards coming out about 6 months later.  However, these are spread around the year, so there's no one time of year that's applicable to all areas of research.
Comment: Fellowships and summer activities certainly have typical yearly deadlines, but do you just want to know about specific research grants of thy kind that professors and lab groups/institutions apply for? The NSF, DoD, and NIH are just a small selection of government agencies in the US, as such a huge amount of funding is federal. The NSF for instance lists year round.
Comment: I'm curious why you want to know? Most people only care about proposal deadlines for their particular field, which as others have already pointed out, can be spread out over the entire year.
Answer: The agencies I'm familiar with (NIH) have published review cycles, and list not only the submission dates, but the approximate dates of first disbursement. Failing this, an email to a program coordinator will probably get you the info you need.  Also, many institutions have grants coordinators whose job it is to know exactly this information (since it accounts for a large proportion of a departments' income). See if you have access to one


Why water won't dissociate more?

Question: In a given sample of water some molecules of water dissociate to give hydronium and hydroxide ion. They say one in 10 million will be dissociated (approx.). What are the reasons behind this? Why water won't dissociate more?
Comment: Under the right conditions of temperature and pressure water can dissociate more.  A lot more.  https://en.m.wikipedia.org/wiki/Superionic_water
Answer: The energy required to break the first $\ce{H-O}$ bond in water is $\pu{493 kJ/mol}$. For comparison, the energy required to break the first $\ce{H-C}$ bond in methane is only $\pu{435 kJ/mol}$. As a point of reference for just what these numbers mean in terms of bond strength, we can think about how long it takes for methane to be destroyed in the atmosphere. The first step of the destruction of atmospheric methane is to break that first $\ce{H-C}$ bond; because this is so difficult to do (again, requiring $\pu{435 kJ/mol}$) it takes an average of about 9 years for a molecule of methane to be destroyed! And the energy required to break the $\ce{H-O}$ bond in water to form hydroxide and hydronium ions is even greater.
I realize that my analogies involve very different processes, but the underlying issue in both cases (atmospheric destruction of methane and self ionization of water) is bond strength. I hope that this gives some insight as to why the self-ionization of water is as low as it is. Don't hesitate to ask for any clarifications in the comments.

Why water won't dissociate more?


What is the community wiki?

Question: This question has been closed, and says something about the "community wiki"... What is it?
Answer: Community Wiki posts are questions/answers that are now owned by the community - votes up or down do not affect the original user's reputation. They are also editable by more users (only requires 100 reputation instead of 1000). The primary goal is to allow a question or a question to be easily updated by everyone involved.
For all the details check out the faq question on MSO: What are "Community Wiki" posts?
Comment: A recent change to the system has removed the CW feature for activation by users. It is now a moderator only feature and can be activated by requesting a moderator to make the change.
Comment: Well, that was lame. What if the moderators can't or won't keep up with the flow of subjective questions?
Comment: @Philip Regan: Flag the post for moderator attention
Comment: @Chealion: I do whenever I catch them. That's where the "*won't* keep up with the flow" came from, or rather (and probably better), *can't*.
Comment: @Philip Regan: Fair enough. Moderators should be on the site more often - as it's part of the job they signed up for. I've been busy lately but have been checking in two or three times a day to check on alerts.
Comment: @Chealion: I'm not casting blame on anyone here. This is a volunteer gig for everyone, so other priorites come first (I'm only here while the Blue Bar of Time is running across my screen, which happens to be a lot). I just disagree with the policy change because I thought the community was policing itself just fine, and moderators have more important issues to deal with than marking clearly subjective posts as community wiki. Bad tactical decision on the part of SE, AFAIC.

What is the community wiki?


What's the policy on potentially NSFW questions?

Question: Let's say I wanted to ask a question about word X in Chinese, X being some potentially offensive term - I might be interested in the exact meaning of the term, the general context of its usage, etc. Is that permitted on this site, and if so, what would the policy on that be (e.g. would it be permitted as long as my discussion of it was appropriately "scientific")?
Answer: From the FAQ:

What makes something offensive and when should I flag it?
Even if a post is a bad post for some reason or another, it is probably not offensive. The Offensive flag is meant to be used only in extreme cases, like hate speech, or abuse.
For example, if a user posts obscene images to the site, that should be flagged as offensive. But if someone says something bad about your favorite technology, that probably doesn't apply.
As a rule of thumb, if you can't justify something as being hate speech, or abuse, you shouldn't mark the post as offensive. Instead, you should down-vote the post.
When you decide to flag a post Offensive, you will get a warning dialog. Take this time to decide if the post is really offensive.

I would interpret that to mean that you would be fine with a clinical discussion of most topics. Be sensitive, however, and warn that your question may offend some. Also be careful to phrase the question as neutrally as possible.
Answer: Further to Don's answer above I also want to remind people of our strict rules around translations, we don't accept questions which are "How do you say ##### in Chinese".
If it is going to have some 'offensive' language make sure there is a need to ask other than just wanting to know or just asking to be shocking/funny.
We want to answer high quality questions with high quality answers. If there isn't a problem you need answered then consider other ways to find out (ask a friend etc.).
Comment: Yep, I was more of thinking of potential questions about connotations or exact meanings (compared to English "translations"), rather than translations per se.


Problem with importing format of data from Excel?

Question: I am trying to import data from Excel. It is located in a single column of the Excel file but each cell contains a comma separated pair of two values as a,b. When I am importing them I have this format {{"a,b"},{"c,d"},...,{"x,y"}, which means just one element not a pair of numbers. How can I have {{a,b},{c,d},...,{x,y}} instead?
Comment: For this specific problem chuy's answer below seems appropriate, but I feel that your actual problem is a botched import in Excel, probably of some kind of CSV file. You probably needed to import that using Excel's import wizard.
Answer: You can use Apply and StringSplit to help out:
rawData = {{"a,b"}, {"c,d"}, {"e,f"}};
Apply[StringSplit[#, ","] &, rawData, {1}]

(*output in InputForm to show structure more clearly*)

{{"a", "b"}, {"c", "d"}, {"e", "f"}}

Comment: many thanks!! if I want in this form of  `{{a`, b`},{c`, d`},...} ,how can I do that?(it is in input form).I mean all just digit.


Is it allowed to publish an extended version of book chapter in as a journal article

Question: In computer science, it is usual practice for researchers to publish the expanded conference paper as a journal article. In most occasions, journals request a 30-40% extended version. However, I am unable to locate any such information concerning chapters published in an edited book. Is it permissible to publish a longer version of a book chapter as a journal article, and vice versa?
Comment: Are you the author of the original?
Comment: Yes, I am the author of original chapter.
Answer: The only binding constraint, other than acceptance by an editor, is copyright. If you don't hold it yourself, then you have to depend on the copyright holder for a license or quote judiciously. This assumes that you want to include substantial sections of the original in the new work.
If the new publisher is the same as the old, permission for copyright would probably be easy to obtain. With different publishers the copyright issue might prevent it. It wouldn't likely be considered a "fair use" as it would probably reduce the commercial/economic value of the original.
You will also need to cite the original as necessary.
Comment: Its a springer book. "Springer Nature authors retain copyright of their book or chapter manuscript. The majority of book and chapter authors will sign a broad exclusive Licence to Publish for their contributions. Further information on copyright and licensing can be found in our publishing policies", but in publishing policies it only talks about Self-archiving policies.


Why does the Pressure ratio across the compressor increases when the mass flow rate is reduced?

Question: I am learning about Rotating stall in Axial Flow Compressors. So, when we throttle the compressor then there is Pressure Rise and later after the peak pressure rise tip stall starts to appear.
But I am trying to figure out the relation between mass flow rate and pressure rise.
Answer: The simplest way to understand this is to refer to Bernoulli's Theorem.  When the flow of a compressible fluid (in this case air) speeds up, the density of the compressible fluid goes down (and vice versa).  Pressure is directly related to density, so pressure also goes down when flow rate (velocity) goes up.
Mathematically, Bernoulli's Theorem is expressed $\rho \times v =$ constant.
Here, $\rho$ is density, $v$ is velocity.
Look at a diagram of a Venturi tube, and it will make sense.


How do I to convert tarrasch-base.tdb into pgn for scid?

Question: I have a tarrasch database in a tdb file that I would like to run into my scid-vs-pc gui. But after spending a lot of time looking for some information on Google, I found nothing that can help me. How do I to convert tarrasch-base.tdb into pgn for scid?
Answer: The Tarrasch Chess GUI is an open source, free Windows download. It uses a proprietary database format and the author approached Mark Crowther, the brains behind TWIC to ask if he could use Mark's database of games. Mark agreed but part of the way Mark makes his living is by selling his full database. There is an export to pgn format function in TCG but to protect Mark's work this feature is limited to 10,000 games.
So, provided your tdb consists of fewer than 10,000 games you can download the program, import the tdb database and then export as pgn. If, on the other hand, you are trying to rip off Mark Crowther's database you are SOL (out of luck). If you are determined to deprive Mark Crowther of his dues for developing his database then your best bet is to download the TCG source code, extract the code for pgn extraction and modify it.


Allow a user to add SharePoint calendar event to their Oulook calendar

Question: We have an event calendar on a SharePoint site. The calendar has several events that occur at different locations and days.  We want users to be able to select an event on the calendar and have the option to automatically have that event added to their Outlook calendar.  Any suggestions.  Everything I am finding on line is about viewing a SharePoint calendar in Outlook which is not what I am after.  Thanks in advance.
Answer: I don't know of a way to do what you are asking.  But if you do choose to view the SharePoint calendar in your Outlook, you can drag & drop a copy of an event into your Outlook calendar.  Then disconnect (or don't) the SharePoint shared calendar.


Is 'darkness upon' in Genesis 1:2 cosmic, rather than merely terrestrial, despite that the central subject and Biblical grammar suggests the latter?

Question: Is 'darkness upon' in Genesis 1:2 cosmic, rather than merely terrestrial, despite that the central subject (Earth) and Biblical Hebrew grammar  (ex:Luke 23:44, Exodus 14:20, Deuteronomy 4:11, Joshua 24:7, 2Samuel 22:12, Job 3:5, Job 17:12, Job 22:11, Job 38:9) suggests the latter?
Comment: I'm not clear on why you are quoting the nine texts. Could you elucidate ?
Comment: Luke 23:44 is in Greek, not Hebrew
Comment: The Hebrew word for *darkness* in Joshua 24:7 is not the same as the one used in Genesis 1:2.
Comment: A very good question Daniel. +1
Answer: The Hebrew word you are referring to is, in Masoretic notation, חֹ֫שֶׁךְ - ḥōšěḵ.*  The Septuagint reading is σκοτος - skotos (also the word used in Luke 23:44, which you cite).
Strictly speaking, it is not the earth (אֶ֫רֶץ - ʾěrěṣ) but rather the deep (תְּהוֹם - tehôm) that is covered by the darkness. The understanding here was that the waters of the deep completely covered the earth, which were themselves completely covered by the darkness.
You state in the question that the verses you cite (Luke excepted perhaps, since it is Greek) all refer specifically terrestrial darkness, and not some cosmic or abstract darkness.  While this seems true in those specific cases (except for Joshua 24:7, which uses a different Hebrew word), it is not true in general.  Examples of other verses using ḥōšěḵ:
1 Samuel 2:9

He will keep the feet of his saints, And the wicked shall be silent in darkness; For by strength shall no man prevail.

2 Samuel 22:29

For thou art my lamp, O LORD: And the LORD will lighten my darkness.

Isaiah 5:20

Woe unto them that call evil good, and good evil; That put darkness for light, and light for darkness; That put bitter for sweet, and sweet for bitter!

Psalm 107:10

Such as sit in darkness and in the shadow of death, Being bound in affliction and iron

The understanding in Genesis 1:2 was that the earth was still without form and void.  The darkness surrounding the face of the deep was utter primordial darkness.  A note in the Oxford Jewish Study Bible (2nd ed.) explains:

This clause describes things just before the process of creation began. To modern people, the opposite of the created order is "nothing," that is, a vacuum. To the ancients, the opposite of the created order was something much worse than "nothing." It was an active, malevolent force we can best term "chaos." In this verse, chaos is envisioned as a dark, undifferentiated mass of water. In 1.9, God creates the dry land (and the seas, which can exist only when water is bounded by dry land). But in 1.1– 2.3, water itself and darkness, too, are primordial (contrast Isa. 45.7).

* Transliterations taken from Swanson, Dictionary of Biblical Languages with Semantic Domains : Hebrew (1997)
Answer: Helllo,
….and darkness was upon the face of the deep (the abyss of man's heart).
For me, the "darkness" is cosmic in the sense that this verse is not literal but a metaphor for the darkened heart (deep/abyss) of mankind void of the heavenly (cosmic?) knowledge of God.    The earth became without form (without His righteousness) and void (empty of His knowledge) as mankind has turned away from God and follows its own paths that man considers as "wise".

Genesis 1:2 KJV (2)  And the earth was without form, and void; and darkness was upon the face of the deep. And the Spirit of God moved
  upon the face of the waters.

God made man upright but they have sought out many "inventions"….contrivances. Man has departed from God's Way and gone after his own ways.

Ecclesiastes 7:29 KJV (29)  Lo, this only have I found, that God
  hath made man upright; but they have sought out many inventions.

The earth became without form…without righteousness.  All have gone out of the Way of righteousness and all have together become unprofitable.

Romans 3:10-12 KJV (10)  As it is written, There is none righteous, no, not one:

The earth became without form….without righteousness (as none does good, not one) and void  of understanding (there is none that understands).

(11)  There is none that understandeth, there is none that seeketh after God. (12)  They are all gone out of the way, they are together
  become unprofitable; there is none that doeth good, no, not one.

Becoming vain in their imaginations…discussions….thoughts, mankind (yet professing himself as "wise") has had his collective foolish heart darkened (darkness was upon the deep).

Romans 1:19-22 KJV (19)  Because that which may be known of God is manifest in them; for God hath shewed it unto them. (20)  For the
  invisible things of him from the creation of the world are clearly
  seen, being understood by the things that are made, even his eternal
  power and Godhead; so that they are without excuse: (21)  Because
  that, when they knew God, they glorified him not as God, neither were
  thankful; but became vain in their imaginations, and their foolish
  heart was darkened. (22)  Professing themselves to be wise, they
  became fools,

The "deep" is the heart of man.  Counsel in the heart of man is like "deep water."

Proverbs 20:5 KJV (5)  Counsel in the heart of man is like deep water; but a man of understanding will draw it out.

The inward part of man and the heart are deep.

*Psalms 64:6 They search out perverse things, 'We perfected a searching search,' And the **inward part of man, and the heart are
  deep*

The words of a man's heart are as deep waters.

Proverbs 18:4 KJV (4)  The words of a man's mouth are as deep waters, and the wellspring of wisdom as a flowing brook.

Those things which proceed out of the mouth come forth from the heart….from the deep…from the inward abyss of man's thoughts and reasoning.

Matthew 15:18-20 KJV (18)  But those things which proceed out of the mouth come forth from the heart; and they defile the man. (19)  For
  out of the heart proceed evil thoughts, murders, adulteries,
  fornications, thefts, false witness, blasphemies: (20)  These are the
  things which defile a man: but to eat with unwashen hands defileth not
  a man.

Mankind needs "recreated" in a sense...reconciled back to God.  Mankind in the darkness of its own heart needs to hear the true, sincere Word of God as men speak His words as moved by the Spirit (the Spirit of God moved upon the waters).
Let there be light….and that light dawns and arises in the once darkened heart of man.  The "evening and the morning":    the light shines in a "dark place" (the evening) as the day dawns and the morning star (the morning) arises in the heart.

2 Peter 1:19-21 KJV (19)  We have also a more sure word of prophecy; whereunto ye do well that ye take heed, as unto a light that shineth
  in a dark place, until the day dawn, and the day star arise in your
  hearts: (20)  Knowing this first, that no prophecy of the scripture is
  of any private interpretation. (21)  For the prophecy came not in old
  time by the will of man: but holy men of God spake as they were moved
  by the Holy Ghost.
2 Corinthians 4:6 KJV (6)  For God, who commanded the light to shine out of darkness, hath shined in our hearts, to give the light of the
  knowledge of the glory of God in the face of Jesus Christ.

The light shines and progresses until the darkness fades and  is no more within the heart….as the light of 7 days.

Proverbs 4:18 KJV (18)  But the path of the just is as the shining light, that shineth more and more unto the perfect day.

Thanks for reading and considering.


REST API to add replies to a share point discussion

Question: I am able to post a reply to share point discussion with help of below link.
REST Call to Post a Reply to a Discussion Board Topic w/o JSOM
but here for posting a message ContentTypeId is required.As of now am getting it from existing replies that have added directly from share point site when a discussion is created.
But when i start to post a first message through sharepoint REST API,it fails because ContentTypeId is undefined.
Is there any way to find  ContentTypeId for replies?
Answer: In your discussion list, click the "Message" content type. You would see the ContentTypeId in the url:


Will there be consequences from Nick Valentine if I join the Brotherhood of Steel while he's my companion?

Question: I do want to join the Brotherhood of Steel, but Nick doesn't like them so I'm afraid he'll leave me or get killed by them, since they don't like synths. I really would like to be able to call in a helicopter from them and have them fry whoever is bothering me.
Comment: Just from what I've observed, you'd be better off *not* calling in a Vertibird. I have never seen them survive a fight against anything with a gun.
Answer: According to the wikia page for Nick Valentine, there are no consequences (good or bad) for choosing to join the Brotherhood of Steel while he is your companion.
However...

 Nick does NOT like it if you join the Institute.

However, according to the affinity chart here, Nick doesn't like if you help the Brotherhood of Steel. Joining should have no negative consequences, but helping them (doing quests for them) will negatively affect your relationship with him.
Note: The Brotherhood of Steel just doesn't like anything that isn't human. Danse insults CVRIE when they interact, but it doesn't affect her affinity, either.


Is it fine to train in the sauna?

Question: If I train in sauna for something like Maraton des Sables, can this have side effects on the long run? What about steam room?
By training, I mean stretching, push-ups, squats, abs - aprox 10 reps every 30 or 60 seconds.
Of course the time spent in will depend on everyone's stamina.
Comment: My guess is that overheating is bad and you may pass out.  Your post begs the question: WHY would you want to do that?..
Comment: I wasn't thinking to overheating, which is obvious. Of course if you overdo it (as I said in the last phrase). I was thinking more if it will affect your lungs or respiratory system in the long run.
I can answer to your question only with another one - how would you train in a colder climate for something like Maraton des Sables?
Comment: I'm not familiar with the MdS, is there an exercise component or is it just the distances? I'm not sure how doing pushups and squats in a sauna will prepare you for the running.
Comment: Pushups and squats indeed are not helping you for running. These are just ways to bring up your body temperature and heart rate (as obviously you cannot run in the sauna), so that you'll be able afterwards to naturally cool it off (like breathing exercises) and get used to the heat.
Comment: Is exercising like doing push-ups, sit-ups, doing jumping jacks in the dry or wet sauna bad for you?
Answer: This is going to sound counterintuitive, but hear it out.
If you want to get better at performing in the heat, train in the cold.
First and foremost training in the cold is a more rigorous workout. Every aspect of improved performance depends on your body becoming more proficient and efficient. The more effective your body becomes at exertion, the less resources it needs to do the same effort. The way the body responds to heat and cold are not terribly different in terms of thermal dynamics. You want your body to be able to move heat, and the more heat it can move the better you are at withstanding heat or cold.
Adding heat load increases risk, and does not work the same as adding weights to a bar. The thermal environment of a sauna versus a desert are too dissimilar to be effective. Indeed I'd surmise the result to be negative. Running in desert heat involves a lovely ballet of air currents you do not find in a sauna. The type of heat is dramatically different - no sun in the sauna.
To improve your body's ability to handle heat, raise it through more strenuous effort. Sprints instead of hours long runs, for example. If possible, do these in colder temperatures, not warmer ones. In the long run, pun unintended, improving your body's native thermal transfer and heat dynamics such as breathing as well as decreasing the time and effort it takes to cross the same distance will serve you better, and without the added risk of heat stroke and decreased rebound and recovery capacity.
If you still feel you must train in a hotter climate, wear layered clothing. Indeed in my experience wearing more clothing rather than less in the desert reduced water loss. While I don't fully understand it, the body does seem to sweat more when more skin is exposed. I suspect it is a dynamic local calculation in order to redirect heat to where it can be whisked away. You might be surprised to learn a lot of desert racers wear full length clothing during the race. Some use "space blankets" even.
Drinking a smaller amount of water will not improve your ability to operate on lower amounts of water. The body needs the same amount of water for the same expenditure of effort. Water is also essential to recover, and going into a deficit will increase your recovery time, thus decreasing your overall training time and increasing the risk of overtraining. Indeed you want to drink often while training to develop the habit. Drink like you should in the desert, not less. How much you drink in the desert will be determined initially by your habit of drinking water. If you habitually drink less, you will automatically drink too little in the event and suffer for it. Learn to drink when it is less critical, not when your life is on the line.
It is a matter of biochemistry, not practice. What you seek is to expend less effort, only in that way can you stand a chance at lower water requirements. Even then, the difference will be negligible. When it comes to sweating how much you sweat is up to your body. Some people are profuse sweaters and others are not.
Generally the more effort is required, the higher the sweat level becomes. The phrase "without breaking a sweat" exists for a reason.
You also need to learn what nutrients and electrolytes your body needs and when. How much do you plan to carry? How much will you decide you really need after the first hour? ;) These are questions you need to answer before the event.
So why train in the cold? In addition to the increased effort, it stresses the body to transfer heat. In a hot climate the body is trying to push heat out into a hot environment. It has no options. In cold it is trying to move heat around the body to get where it needs to be. This thermal dynamic improves your ability to shed heat. When I was in the desert, those who came from hot climates always did worse than those from cold ones when it came to handling exertion in the heat. Sure, they didn't view the heat the same way, but they didn't handle it as well either. Maybe they didn't respect it, or maybe they were physiologically unprepared for it, I don't know. Just that they didn't handle it as well.
All that said, your other preparation will be more important, and is often overlooked. Consider what you need to do to protect your body on the dunes. Heavy sunscreen. This includes clothing as well as pastes. Sand. Lots and lots of sand. Ever run with sand in your shoes?  Know how to handle that? These will be greater impacts than you realize. Many think the heat is their greatest opponent in the desert. They are wrong. You need to learn to move and run while minimizing the entire environment. Direct sunlight is your opponent, sandy shoes are your opponent.
I know it sounds crazy, but take it from someone who spent crazy amounts of time in deserts while ending to do high intensity activities. You won't be defeated because you didn't train in the heat. You'll be defeated because you didn't plan for the rest of the environment. Run in leggings, paste, full body protection, gaiters, sunglasses, gear on, etc. Do these things not because they might make you better, but to create the habit of wearing these items as extensions of your body.
Cheers, and good luck.
Answer: Apart from the strange looks you would get from other users(unless sauna is private). I can't imagine this would be overly useful. I suspect you would need to come out of the sauna long before it would be really useful for heart and lungs.
I have trained for hot overseas marathons in the past.  Admittedly through a Uk summer.  I trained by wearing thermal top and legging. Ie overdressing
My race was in Greece and it worked for me.  Although I guess Marathon de Sables would be hotter.
Comment: @AdrianBer - UK has summer. You just have to not blink at the right time. :p
Comment: A race in Greece, unless is midday in July or August is not that hot. Overdressing could be enough for that one.
UK does not have summer :).
Comment: @AdrianBer - uk summers lol I agree, but that does make it harder to train for a marathon in Greece. I also trained for a half in Morocco in the same way.  Sorry if you don't think that will help:(
Comment: @Tracyat2bactive I did not say it doesn't help, I just said it's not enough. Ahh, btw, if you mind the strange looks (no matter the cause), then my personal opinion is that sports (especially endurance ones) are not for you.
Answer: Hey Adrian,
I didn't know about Maraton des Sables, so I had to google it source.
Based on the information gathered, I don't think that any of those exercises will help your preparation for that competition.
The goal of the competition is to be able to withstand the heat with as less water as possible. Sauna is basically steam; so, while it might dehydrate you, it doesn't give your body the same experience as what'll be experienced in the actual competition. If you have a way to simulate the dry heat, that would have been your best option; if not, sauna seems like the next best thing.
As for the bodyweight exercises, I don't think those are necessary as they wouldn't help your body conserve its usage of water, a highly needed requirement in the contest.
What exercise to perform in it? None, except being able to withstand the heat as long as possible with limited water consumption. You probably need to consume less water daily as the contest approaches too, so that your body begins to adjust to the new water requirement.
Good luck on that and do let us know how it works out :)
Comment: There is also dry sauna, not only steam room.

I don't think that you'll be able to train for less water consumption. Or at least not with great results.

If you run for 15-20h straight, your body sweats no more (or much less), so water consumption will not be the biggest problem, but overheating. This is what your body needs to get used to.
Answer: I train in the sauna atleast twice a week, 175 - 250 squats non-stop. Takes me 20 minutes+ I used to do crunch-ups.
This is Hard... So something is getting stronger, right ?
This sauna effort of mine has been built up over 15+ years.
Try what I do on day1 and your heart may stop. And be unsustainable. Patience and discipline are key
Try to contain your ego and ramp over time (10+ years) and your blood sugars will drop(mine went from 320 to 80+ no kidding) and your cholesterol numbers will also improve overall. As long as you are sensible about your diet ( watch junk food intake, eliminate no foods, try balanced diets)
Also my lifts have improved beyond expectations. I cant lift as much without the Sauna Squats, they relax my muscles between lift sessions
At age 55+ I strict curl 140 lbs, squat 315, bench 275. The curl is above most state records for my age weight category
My treadmill stamina drops off without sauna workouts also.
Dont just read and post.
TRY out things. You may not get the same results I did,each persons bidy is different.
But if you ramp slowwwly you may learn a few things.
The first to improve will be patience. And a desire to KNOW for yourselves by trial error and retrial.
Good luck
Comment: In the future, rather than answering twice, please think about how you would answer the question the first time, so that only one answer is necessary.  Then, if you need to, you can edit your response.
Answer: I wished to add that the opposite of this (or whatever you have been doing)  is also great for conditioning.
I do switch out from the Sauna to the pool, back and forth.
Opposites always reduce stresses accumulated
I sweat a lot in the Sauna, no liquids while in Sauna, All liquids before/after for my training
Lastly, I no significant lifting etc on days of long sessions in the Sauna ( long for me is 100+ squats, will be different for each of you).
Heavy lifts running etc restart on the day following Sauna extended squats

Is it fine to train in the sauna?


promoted links customization

Question: I am trying to customize promoted links in SP2013 using css but I am not able to do that ... the transparent block doesn't move after giving top & width parameters , am I missing something ? I just want same behavior with increase height & width of the box.
Comment: The overlay animation is controlled through JavaScript, so if you set a `top` value for it the animation is defeated.  See my answer here: http://sharepoint.stackexchange.com/a/169304/8992 and this other question here: http://sharepoint.stackexchange.com/q/108839/8992
Answer: Add a script editor web part and paste the css provided here:
http://www.underthefleece.co.uk/2015/02/change-size-of-promoted-links-in.html
Comment: the animation doesn't work properly , it is useful for shrinking not to enlarge.

promoted links customization


Why does the outer layer of the sun have differential rotation?

Question: I don't feel that way myself but some might find it really strange and wierd that it has differential rotation and feel that it's a contradiction. They may say "How is it possible?" I am asking on behalf of others who might have that question what assumptions they are making and how to break them.
Comment: Does this answer your question? [What is the exact reason for the Sun's differential rotation to occur?](https://astronomy.stackexchange.com/questions/45082/what-is-the-exact-reason-for-the-suns-differential-rotation-to-occur)
Comment: At least to those unaware of it or surprised by it the https://en.m.wikipedia.org/wiki/Differential_rotation page should suffice.
Answer: In principle, differential rotation can refer to (at least) two different things:

The sun (or any star) rotates about an axis and so are not perfectly spherical, but rather oblate: flatter at the poles and bulging at the equator, similar to the Earth! I think the OP is not referring to this.

Any star composed of multiple layers (i.e., not very low mass main sequence stars), can experience different rotation rates for each layer, I think this is what the OP is referring to. It is known as "internal differential rotation." Our sun is an example of such a star. But it is complicated, because the amount of internal differential rotation depends on the amount of coupling between the angular momenta of the various layers. This coupling is physically due to chemical mixing across the layers due to turbulent and viscous convective processes, and magnetic fields can play a role.

For simplicity, consider a star with a core and an envelope that was born with some nonzero amount of angular momentum (spin). As the star ages, it can lose some spin due to wind mass loss. By the end of its life, it will lose its envelope (to strong wind mass loss if in isolation or to mass transfer if bounded with a companion). The process of losing its envelope can deplete the core of spin if the coupling between the core and the envelope is strong, i.e., angular momentum will be transported out of the core by the envelope, resulting in a slowly spinning core (which becomes a late stage star, i.e. a Wolf-Rayet star). On the other hand, if the spin coupling between the core and envelope is weak, then the spin of the core is essentially independent of the spin of the envelope (and consequently of the initial spin of the star!). Thus, these two extremes can be thought of as two extremes for differential rotation: strong coupling implies the same spin between the core and envelope, i.e., no differential rotation; whereas weak coupling implies uncorrelated spins of the core and the envelope, i.e., yes differential rotation. The physical mechanisms/processes that cause the spin coupling between stellar layers is complicated and an open problem in stellar evolution theory, however a lot has been done in recent decades in various regimes, for example this and this. For a population synthesis study that parameterizes the effect of this coupling on black-hole binary spins, see this work by Postnov $\it{et~al.}$ (2018), specifically section 4.1 and references therein.
Comment: The outer layer of the Sun does not have differential rotation in the sense that you discuss. Convective zones tend to rotate as solid bodies. The Sun's outer layers have differential rotation with latitude.
Comment: indeed, but the Sun isn't fully convective?
Answer: I think they're not taking into account the Coriolis force in the frame of reference of the part of the outer layer of the sun at each latitude. I can't quite think of a proof that the outer layer of the sun would be predicted to have differential rotation. However, when you realize about the Coriolis force acting on the convection currents, you see that it does not give you a proof that there shouldn't be differential rotation. Maybe the part at one latitude then exerts a force on the part at an adjacent latitude until the rates of the two layers satisfy a certain equation.
Comment: I think that answers should not begin with "I think" followed by "I can't quite think of..." This should be part of your question, not the answer to it. Answer posts need to really strive to be proper answers, not speculation. Why not move this back into the question and wait for an answer with some more certainty?
Comment: @uhoh I think the answer is useful because what it does is resolve the apparent contradiction.
Comment: @Timothy Did you ask the question and then answer it yourself?
Comment: @Timothy it is always okay to post an answer to your own question in Stack Exchange, as long as it's a good answer. It's just that in this particular case the post *as currently written* is not yet a stand-alone answer, so "I think" it should still be part of the question. (You can verify this by clicking "Ask a Question" and checking the bottom of the edit box, there's even a check box with an explicit invitation to answer your own question at the time of asking)


What are the fundamentals of a serving toss in tennis?

Question: On my tennis serve, how do I properly and consistently do the ball toss?
Answer: There are a few parts to having a consistent ball toss:

Release the ball when the tossing arm becomes close to fully extended. This allows you to control the trajectory of the ball in one smooth motion. If you release too early or do not use a straight arm, the ball can experience inconsistent acceleration from your hand.
Slow down your toss motion. It's more difficult to control a fast motion, which can lead to an unpredictable toss.
The toss should be as low as necessary. The higher the toss, the more wind can affect it (due to prolonged exposure), the more difficult it is to toss consistently, and the more difficult it is to time. Optimally, you should make contact close to the height of the toss, but it might be difficult if you lack the racket-head acceleration, in which case you may need to toss higher for more time.
You should hold the ball with your fingers rather than your palm. This will allow you to have more control on the release.

One piece I didn't include was location. This is difficult to give advice because it depends on the mechanics of the server's stroke, which largely depends on his/her skill level and athleticism. It also might depend on different serves. It's common to vary the ball toss location with different serves. For instance, with slice serves, a ball toss more to the right (of a right-handed server) could allow for more rotation around the ball at the expense of power. However, this becomes too easy to read at the higher levels and doesn't allow variety in location for these serves (e.g., it's more difficult to hit a body-serve).


Was it impossible for the Germans to arrange a plane to East Asia for Subhas Bose?

Question: Bose's journey from Germany to Singapore by submarine was a well-remarked incident of World War II history. But what was the need for the Germans or the Italians to use a submarine to transfer a civilian? Was it impossible for them to arrange a flight? Or was it done to force Bose, whose relationship with Hitler was frosty, to make an uncomfortable and unsafe journey?
Answer: No, it wasn't possible to take a plane.
As I mentioned in the (currently accepted) answer to Which city was attacked by Nazi-German war flights in India during WW2? , the Nazis did not possess any plane capable of making a flight from German-controlled territory to India, much less Japan, without stopping for refueling, and they did not have any aircraft carriers.
Even so, airplanes in WW2 were not nearly as safe as they are today. Worse, they can be spotted, and if spotted in range of an enemy air field fairly easily taken down. This is, in fact, how the allies killed Admiral Yamamoto. So it is quite likely submarine transport would have been safer, even if air transport was an option.
In fact, the transfer to the Japanese sub occurred 10 days after Yamamoto was shot down. Its likely both Bose and the Imperial Navy wouldn't be inclined to risk another VIP that way so soon.
Comment: @DVK - A bit of both. Without the sigint they wouldn't have known where or when to look. But to borrow from Douglas Adams, The Pacific... is big. Really big. You just won't believe how vastly hugely mindbogglingly big it is. Presumably the same sigint would have been just as capable of finding out that the Japanese were transporting Bose, but a submarine would have been much harder to find.
Comment: trying to envision a route they could have flown, and indeed it runs into trouble over the Black Sea, a long way from Japan. While Turkey and Iran weren't active warzones, they were nominally under allied control as far as Germany was concerned. India of course was British controlled, as was Afghanistan. Even a Condor would be unable to make it from Romania to China nonstop.
Comment: @jwenting Then how did the diplomatic staff of the Allied powers travel?
Comment: @Arani The allied powers controlled the seas, traveled by ship mainly. They also had access to the small number of very long range flying boats like the Boeing 314 Clippers. And of course they controlled large contiguous landmasses, allowing them the luxury of safe airports at convenient intervals.
Comment: Wait... wasn't Yamamoto killed as a result of sigint, and not being "spotted"?
Comment: Very interesting answer, +1.
Answer: Bose was sent on U180, a specially built fast cargo submarine whose main role was to refuel other U-boats operating in the Indian Ocean, however its cargo also included three tons of Gold for the German Embassy in Tokyo, therefore the handover had several diplomatic aspects.
Source
The Bormann Brotherhood, 1974 William Stevenson (former WW2 RN intelligence)
Answer: In fact Abwher parachutists were infiltrated by air into Afghanistan and these men were responsible for collecting Bose from the Khyber pass and leading him to Kabul where there was an airstrip used to repatriate him to Germany via Rhodes.
Some time later there was a flight to China made by the Italian Servizi Aerei Speciali using the SM 75 aircraft, "MM-60539." The original successful flight left via the Crimea at great peril so the second of these flights was proposed via the same airfield in Kabul.
Some Italian archives are available which detail this:
Sources:
ACS, Ministero Aeronautica, Gabinetto, busta 69
Vol 9 Gabaereo to Ministero degli Affari Esterni November 13, 1942
Vol 10 Ministero dell' Aeronautica Appunto per il Duce November 13, 1942
Vol 10 Gabaereo to Stato Maggiore R.Aeronautica November 17, 1942
Vol 10 Gabaereo to Stato Maggiore R.Aeronautica December 1, 1942
There was no need to infiltrate Bose back into India as he was worth more to the Axis being sent back to Japan via the submarine base at Singapore to influence Indians in Malayan POW camps to desert and join the Axis cause


Is it possible to determine good and evil in a vacuum?

Question: Without any context of time, situation, or people involved, or any other situational variable is it possible to tell right or wrong, good or evil? Why/ why not?
Answer: Moral realists like Kant surely think so.
And from a more naturalized Kantian position, we can accept the basic argument in a modern framing -- we get something like Freud.  Humans have a certain fund of expectations which come down to us genetically and through the shared layer of culture that hold the species together and keep it functioning.  Respecting those and allowing them to do their work will be seen by most people as a reasonable definition of good.  The remainder are lying.
Something like the thoroughgoing empathy of Kant's Categorical Imperative is hard to see as evil, or even neutral.  One has to work very hard to make situations where one wishes to ignore it, and even then, there are always slightly more productive paths out of those staged dilemmas, which respect the rule.  We resent the degree to which such a notion would constrict our behavior, but we cannot really claim we do not expect the principle to be followed by at least the people most important to us.  We expect those we love to be fair, and although we play with contextual details, we do have an overall sense of what fairness is.
Any applied theory that works is still going to be negotiated on top of some shared base.  Its underlying notion of good is still ultimately going to trace back to shared opinions that arose over time out of these principles.  So disowning the idea that a few basic principles are not always good is just casuistic evasion.  If there were no basis to morality, different cultures could not make peace on a regular basis, which they simply do.
At the same time, we have a strong tendency to focus on only one side of human nature as good, the one that works longer term, and accept more basic competing drives as necessary evils.  But there is not really a place for that bias.  Conflicting drives that are productive and universal should be seen as competing good impulses to be reconciled, and not viewed in terms of good vs evil drives.
It is this intricate balancing act that makes morality seem baseless, because we are too firmly attached to the simplicity of negation.  Morality may not be, in and of itself, logically consistent.  That does not mean it does not exist or have structure.  The same can be said of all forms of taste, but overall, we have not seen the basic nature of things like food change in thousands of years.
Answer: There are two differing opinions on this:

Moral Realism (or Moral Objectivism): right and wrong, etc...are objective truths independent of individual perceptions or beliefs, of social circumstances, etc....see this post and Jobermark, Virmaior and Quentin's responses to it.
Moral Relativism: the opposing position that all values and ethical propositions are dependent on social, historical, cultural factors, etc....see this post and answers within.
Comment: @JesseCohoon one might resort to intersubjectivity (agreement on subjective experience between multiple individuals), but as Philip pointed out, that tends too easily to swing into one direction or the other. What Jobermark mentions seems to be the current pragmatic solution adopted by  pluralistic societies (reducing the number of objective ethical axioms to a very small core and agreeing that the rest are all relative), but even those get challenged...see the current American culture war.
Comment: Could someone have a "middle of the road" taking the strengths of each of these positions for different types of actions?
Comment: @JesseCohoon: The problem with 'middle of the road' is a slippery slope: Once you allow for moral judgements not to have an absolute standard, it is impossible to argue that one position is better than the other. So if you think it through, you end up in either more or less well conceiled moral realism, or some kind of 'absolute' relativism, where it's only up to factual status (e.g. cultural setting you were born in) or even taste what is right and wrong and you can hardly argue against ANY position.
Comment: Sorry to post the same idea concurrently.  Another way of looking at this is that logically any moral relativism with a tiny bit of moral realism mixed in is still moral realism, just with a smaller set of axioms and more construction.  There is never any 'balance' between a limited principle and an absolute one.  There is a strong motive to keep the realist part as compact as possible, and leave as much space relative as is workable, but that is not a 'middle of the road' position.


Organic molecules with fast non-radiative decay rates

Question: What structural features in an organic molecule would promote fast non-radiative decay to a ground state, for instance in an aromatic π-conjugated system ?
Answer: Anything that has potential energy surfaces that cross or get close in energy. Offhand things like s-indacene and the indenofluorene family of compound, there are many others as well (azulene mentioned below). In general, if the $S_0$ and $S_1$ state for a $\pi$-conjugated organic come close in energy there is the possibility for all of that energy to be used on vibrations instead of luminescence. As far as predicive rules, that is a difficult thing to generalize. Perhaps you could argue that a low $S_0 \ce{->} S_1$ transition energy opens the possibility for non-radiative decay since these potential energy surfaces are not seperated by much energy, biradicaloid $\pi$ systems fall in this category.This is the same reason there is typically not emission from higher energy state, $S_n \ce{->} S_1$ transitions are usually quite close in energy and have crossings to get to $S_1$ efficiently through molecular vibrations. For further examples and explanations see, for example:
http://www.sciencedirect.com/science/article/pii/S0009261414008847?via%3Dihub
Or Josef Michl's excellent book "Excited States and Photochemistry of Organic Molecules" for more details on the topic.
Comment: Not an expert on this by any means but azulene was the example that we were taught (ultrafast S1->S0 internal conversion). Then again, I don't know what "structural features" would lead to an intersection between the PES's.
Answer: The cause fast non-radiative decay (excluding reaction, such as cis-trans isomerisation, as a non-radiative event ) is spin-orbit coupling which links singlet and triplet states and opens up a non-radiative pathway between them, in addition to fluorescence and internal conversion. The SO coupling 'breaks' the forbidden singlet-triplet selection rule. In internal conversion the operator is anharmonicity since no spin change is involved.
The second important factor, but only in the condensed phase,  is the gap between the initial and final electronic states, the smaller this is the the larger non-radiative rate constant. As this is an application of a Fermi Golden Rule it is quite general and applies to all molecules not just aromatics. This answer explains it in detail Non-radiative transitions or what features of rhodamine result in it being so highly fluorescent?
Additionally heavy atoms, as a substituent or a solvent, increase non-radiative rate constants (again by spin-orbit coupling) as do paramagnetic species such as molecular oxygen dissolved in solution.
Should also mention that dipole selection rules for fluorescence /phosphorescence via excited & ground state symmetry means an additional factor is present to determine if the excited state is long or short lived.


USA Southern Border Vehicular and Pedestrian Obstacles

Question: Is there a GIS source that contains the location and type of obstacles along the USA Southern border?  Additional meta data would be great as well; when it was install, dimensions, materials, number of repairs, and so on.
Answer: Homeland Infrastructure Foundation-Level Data (HIFLD) has an Open Data Portal where most of this data can be found.
HIFLD 2018 Data Catalog (<code>.xlsx</code>) lists all of their open data wares for the year.
Specifically, borders, boundaries, natural hazards, and transportation ground datasets seem pertinent here.
Note: if the portal isn't definitive enough, go through the data catalog; searching for "border" returned six results, whereas searching the portal for the borders tag only yields three.
Answer: all I know is they might have what you are looking for...
https://www.ibwc.gov/home.html
They have their geospatial data there.


Could we still plunge modern civilization into another black death?

Question: Many thought it was the poor hygiene and inadequate medicines that laid waste to the entire world -- particularly Europe -- as millions of lives were lost, although the death toll only subsided but it would be centuries before the population starts to show signs of recovery. I'll cut to the chase: today humanity took on Ebola and H5N1 and its variant head-on; both are often labeled as deadly but these epidemics never came close to Black Death during the middle ages. I need a powerful pandemic to cripple the entire world -- something that rivals the black death... by the way I already considered nuclear holocaust but not when only one leader is trigger happy about it, right Mr Kim?
Comment: Certain WorldBuilding questions, when read without context, can look like an evil force crowd sourcing its world-ruining plans.
Comment: Steven King did it in "The Stand"
Comment: Does high mortality among healthy adults, leaving alive elders, kids and immunocompromised adults suffice? I know of a way to get disease to do that. If it suits your needs, I'll write full answer later.
Comment: If you want a 'big bad' to be the one setting it all off, you could have some "false flag" deadly disease be reported, when everyone goes to get vaccinated, they're infected with the actual virus
Comment: Separate from the nature of the cause, the "deployment" could matter.  In particular, if there were some reason disease researchers worldwide were hit first, then conquering a new pathogen would be exponentially harder.
Comment: Does it have to be pathogen based? Airborne carcinogens and allergens are far more likely to kill in the long term
Comment: Can it include bacteria that has become immune to antibiotics?
Comment: There's a decent television series that centers around this called "The Last Ship" which you might be able to get some ideas from (based very loosely on a William Brinkley work, though the novel doesn't revolve around a pandemic).
Comment: I can see a new, highly sensationalized (on a global level) vaccination scare causing vast swaths of the human population to remain uninnoculated.  I would think even a moderately dangerous pathogen could have deleterious effects in such circumstances.
Comment: @Engineer Toast: like the cat & mouse game whereby neither side wants to give up, by exploiting every possible scenarios can we be better prepared for the looming threat hiding around a corner.
Comment: There's a game out there that does recreate a worldwide virus epidemic in a realistic way.  You start by infecting one person then change and adapt the virus symptoms and deployment to make it as effective as possible.  I'm not sure if I can use it's name so I won't unless I get an okay in which case I'll edit.
Answer: You need a virus that starts to be contagious early, but give the full spectrum of symptoms late.
If your virus is fast to act, it will be caught in quarantines and studied. If you want pandemic scale event, you need it to spread "disguised" as common cold or something equally innocent, and only kick in when it's already too late and substantial portion of humanity either caught it, or was exposed. Then, after months, virus should kick in - but it should be already built into cells' DNA, or in some organ you can't cut.
That said, bioengineered herpes or retroviruses would be my best bet. Given that 5 to 8% of our genome is made of retrovirus DNA, it's not a far fetched idea that a virus infection may spread, and then only kill months, years or even generations later. Herpes can be reactivated by increased level of radiation. You don't have to have a nuclear war, some accidents may suffice.
Imagine the dread - black plague happened in your grandpa's generation, they was there to stop it... but they didn't, and now something triggered it and it'll kill you. With our level of medicine and sanitation, I think that's the only way for such disaster to happen. Sure, no single virus has all the traits I'm describing, and let's be thankful for that, but it's believable enough.
Comment: "If you want pandemic scale event, you need it to spread "disguised" as common cold or something equally innocent" *laughs in 2021*
Comment: Comments are not for extended discussion; this conversation has been [moved to chat](http://chat.stackexchange.com/rooms/51649/discussion-on-answer-by-molot-could-we-still-plunge-modern-civilization-into-ano).
Comment: @AndrewGrimm Oh. My. Gosh!
Answer: Humanity had a near-muss with the SARS virus. It had mortality approaching 40%. Fortunately its infectivity was low enough that mere changes to human behaviour were sufficient to convert it from an exponentially growing infection into one that died out. (Face masks, gloves, avoiding physical contact in business and social settings).
Next time we may be less lucky. What to be most afraid of is a virus which is endemic in some common non-human species, which mutates into a strain deadly to humans without losing its ability to be spread by the other species. It would also have to spread fast before we could develop any vaccine or effective antiviral drug.
The Spanish flu was the last time this happened. (Flu is spread by birds and/or livestock). It's possible that at least one of the mediaeval plagues and the Roman "plague of Justinian" were not plague (now curable) but some other viral epidemic. Flu or some emergent virus like SARS are candidates. Fragmentary records and the primitive medicine of those times make it hard to be certain.
Smallpox was also a virus that emerged in near-pre-historical times (and we have clear historical records of what it did in the Americas where the population had no historic immunity).
It's possible that we could inflict this or worse on ourselves,  but it would take a team of lunatics to do it. Plagues do not discriminate between friend and foe. If some country or group had pre-vaccinated its population and somehow kept that secret in advance, it would rapidly become clear when the plague struck. Retribution would follow, probably nuclear.
Comment: Out of interest, where did you get your 40% mortality figure? The [WHO](http://www.who.int/csr/sarsarchive/2003_05_07a/en/) say overall 14% or 15%. And even they are deaths in people who were infected and went on to develop observable symptoms and be diagnosed.
Comment: @Spratty Why would anyone listen to some 60's band about virus mortality?
Comment: I cannot recall where I read 40% mortality. It may not be accurate, or it may have been for early cases before medics knew what they were dealing with. On the other hand most later victims got good modern medical care. Had it gone exponential then hospitals would have been overwhelmed and the mortality rate would have been higher.
Comment: @Samuel, my generation would, for a start.
Comment: @Samuel 60s? [They've](https://en.m.wikipedia.org/wiki/The_Hu) been releasing new songs within the last year.
Answer: You need very specific disease. Lethal, infectious, virulent and transmissive but with low visibility, long incubation period, slow acting, initially asymptomatic or at the least non-specific (hard to distinguish from more benign diseases) and hard to treat.
Lethality.
Disease which is too lethal runs the risk of killing or immunising (those who survive, do so because their immune system beat the pathogen, and thus, they become immune, they may or may not still be hosts, depends on disease, some stay forever, just suppressed) entire host population before it has a chance to spread, not to mention it's highly noticeable.
Infectivity
Infectivity is an ability to cause infections, to establish itself within the organism and evade latent immune response. There are a lot of bacteria and viruses around us and immune system is good at eliminating or suppressing them before they can cause trouble. To cause an infection, there needs to be enough of pathogens so that they either locally overwhelm immune system, or at least few successfully evade it, start multiplying and overwhelm immune system later. The more infectious the disease, the less pathogens are needed.
Virulence
Virulence is ability to cause damage to the host. It's correlated with both infectivity and lethality. The most infectious virus or bacteria will be harmless if it doesn't actually do anything harmful. Ways how pathogen can cause damage are varied. Bacteria eat or poison tissues, viruses take over cells and literally overwork them to death, making more copies of the virus. There is one unusual way of which I will speak later.
Transmissivity (did I build the word correctly?)
Transmissivity is an ability to use different modes of transmission for horizontal transfer (from one host to another). The most obvious is through body fluids, for example blood. But that won't do for your purposes, those are easily contained. Water-borne pathogen won't do either, that's not enough. Droplet transmission (transmission through tiny droplets released during coughing/sneezing) is getting there, but what you need is truly airborne disease, capable of surviving in air for a long time and circulate through air conditioning.
Incubation period
Is the time since infection to appearance of first symptoms. Host may or may not become infectious before showing symptoms, depends on disease.
Symptom
Is a visible effect of a disease. Asymptomatic means without symptoms, since death is the most severe symptom imaginable, your disease can't go entirely asymptomatic.
Taken together, analysis of some famous pathogens
Ebola
Ebola is right out. Severe bleeding gives it its high virulence and infectivity and lethality (it's very easy to catch disease by contact with blood, and bleeding weaken the organism), but at the same time makes it very visible, and since it's not airborne and thus not very transmissive, it's easy to contain. Also, it kills too fast. Unless vaccine/treatment was discovered recently, best course of action is to quarantine the area and let the virus "starve" itself, it will run out of new bodies to infect and disappear quickly. Fruit bats apparently are the reservoir of Ebola (animals which can carry it without getting sick - it's benign and asymptomatic for them), which extremely limits Ebola's ability to stay dormant in animal population outside of Africa - continent of its origin (if it could infect rats, that would be completely different matter).
Smallpox
Smallpox is out too. Mortality of 30% is too low for your purposes, furthermore, effective vaccines were developed, used both as treatments (when given very early during infection) and pre-emptive measures, leading to its effective eradication. If it somehow came back, we know how to handle it. It would take some time to collect new viral samples, compare with retained ones and re-establish vaccine production, but we know how to do it and we did it once, we can do so again.
Bubonic Plague
Bubonic plague is in. Mortality reaching 90% in some outbreaks, proven track record (killed 50% of European population in 14 century) and nearly 2 week incubation period sound promising, but while vaccines are not very effective against it, antibiotics are. It's transmitted and hosted by fleas (to which it's harmless), which ride around the world on ever present rats, making controlling and quarantining it tricky, but not impossible. If you make it antibiotic resistant (which is happening to many bacteria due to overuse of antibiotics), somehow increase the reservoir to house pet fleas, you might get quite a lot of mileage out of this one. It's still highly visible, so after extreme containment measures, including extermination of rats, mice and all the house pets in affected areas, the threat will fade, you need your fleas to somehow bite a lot of international flight passengers to spread it before it's discovered and containment begins, that's going to be tricky. In first world rats and fleas are exterminated, in third world, the disease might "tip off its hand" too early, by infecting some village or small city, I assure you that this one would be taken way more seriously than Ebola was (Ebola was known for nearly 40 years now, but it never was and never will be a serious global threat because of reasons I outlined earlier, unless it evolves to be airborne or something like that).
Influenza
My personal favourite, but actually less plausible than Bubonic Plague.
Thanks to being airborne, influenze has extremely high transmitivity and infectivity, it however has very short incubation period, which means that depending on where the outbreak starts, it might be very easy to contain. Even in worst case scenario, it should be easier to quarantine than less transmitive diseases with much longer incubation period, and stable animal reservoir. Furthermore, influenza mutates rapidly, this means that it can become highly lethal out of the blue, but also means that lethal strains will starve themselves out of the hosts (because virus NEEDS the host to survive, or live at all, since it's an ongoing debate if viruses are actually alive at all, they don't have all the organelles to qualify as truly alive), and eliminate themselves out of the flue gene pool, leaving less lethal ones. It's a debate as to the true cases of mortality of Spanish Flu, one of the proposed is triggering a positive feedback loop in immune system reaction, causing it to effectively kill the body (you know how in cartoons multiple characters start fighting in a ball of dust and then the one who cause the fight slowly crawls out leaving rest to beat each other senseless? That's similar thing), making healthy adults more susceptible due to the strong immune system, whereas people with weaker immune system just suffer it like normal flu. It is however possible that reason behind mortality of Spanish Flu was external, 1918 was the last year of the Great War, shortages were widespread, and conditions were bad, both at the front and in far behind them. It's possible that this particular strain merely hit at the right moment, when supposedly strong people and societies were weakened, and flu was merely able to pave the way for secondary infections which would be what claimed the lives. Either way, you can get some serious mileage out of this, but you need to pick the moment and place right, since it can't stay hidden for long. Deadly flu would have to rely on being mistaken for normal (mostly harmless) one during first week, while asymptomatic hosts spread around the world, but after people start dying, it has no way to hide.
Comment: AFAIK there were no shortages in the USA caused by WW2. The Spanish flu was just as deadly in the USA. Also it was deadlier in young fit  people than in middle-aged people (with statistically  *less* active immune systems.)
Comment: I suspect that the flea vector of bubonic plague is far less dangerous in the modern world. If you don't keep a pet, when did you last get bitten by a flea? And that's before we see the threat and unleash insecticides in large quantities in our habitations. In the mediaeval world,  flea-bites were an unavoidable daily hazard.
Comment: @nigel222 Fleas are not going anywhere. Apparently, USA citizens alone spend nearly 5 billion a year, trying to get rid of them. Furthermore, there are a lot of "wild" animals in cities, from rats to foxes, and fleas with them. Yes, fleas are much less of a threat nowadays, but they are hardly gone, and such vector and reservoir is NOT impossible. However it would be important for disease to use more than just some rodents for reservoir.
Comment: Well, my experience was moving into a house that previously had pet cats. A week later the fleas they left behind got hungry. Two weeks and two cans of flea-killer later and I got my last bite. None since then, and I can't remember any previous. Plenty of foxes around my house, and (proverbially) rats within ten feet. No flea bites.
Comment: Smallpox (along with measles) was at least 90% lethal in the Americas where there was no population immunity. Smallpox would have done the same in Eurasia when it first emerged. We know that must have been after the land-bridge between Asia and America last closed, but before we have historical records.
Comment: Correction to above (can't edit): up to 90% lethal in Americas, not at least.
Comment: «they don't have all the organelles to qualify as truly alive)» you make it sound like they have *some*, and that all cells do as well. None of that is right.
Comment: "due to overuse of antibiotics" This phrasing has irked me for a long time. *Any* use of antibiotics would eventually result in resistant strains, even if you limited to only the cases where people provably had the infection. Chemical resistance is a prominent adaptation observable in biology. The only way to prevent resistant strains from developing is to not use antibiotics at all. (Well, even then, some could be resistant, but it wouldn't matter.)
Comment: @JDługosz Viruses do have organelles. Capsid is an organelle. DNA/RNA complexes are organelles. So yes, viruses DO have organelles. Cells which miss too many organelles may stop being fully alive, like red blood cells.
Comment: @jpmc26 Yes, any use of antibiotics (or any other anti-bacterial factor) exerts selection pressure. Yes, that statement is a shorthand, and I used it to reiterate fact that irresponsible use of antibiotics makes this process much faster than it has any business being. I'm very much against casual use of antibiotics and antibacterial factors.
Comment: @Miech I don't know what "irresponsible use of antibiotics" is. Most doctors prescribe antibiotics because they believe their patients either have contracted or are at significant risk of contracting an infection. They do this to *improve and protect the health of their patients*. Are you seriously suggesting that they should just let their patients get as sick as possible before using an antibiotic? That's dangerous to their patients. Unfortunately, caring about the well-being of your fellow man is at odds with letting selection run its course.
Comment: @jpmc26 Irresponsible use of antibiotics is: liberal supplementation of animal fodder with antibiotics ("Eighty percent of antibiotics sold in the United States are used on livestock.", https://en.wikipedia.org/wiki/Antimicrobial_resistance , freaking idiots), sale of antibiotics without prescription (depends on country, but still will create global problem), use of antibiotics in viral infections, or infections which don't warrant nuclear option. Not every bacterial infection needs to be treated with biological equivalent of nukes, you know.
Comment: And if some wise guy smashes a vial of ebola into the air condition intake ducts at LAX?
Comment: @Miech I learned that *organellee* were specifically membrane separated compartments, not just any microcomponent.  IAC the real point is that viruses have no **metabolism**.
Answer: It's as much modern attitudes to sickness that have changed as modern medicine. In most western countries it's considered unacceptable to spread it around.
Consider a normal person with a severe illness. Most people in such a situation would call in sick and not go to work. Those who do go in are frowned on by colleagues for risking other people's health. You don't "man up" and go in regardless because that's antisocial. This means that even though we live in a high density world, and theoretically diseases could spread very rapidly, our attitudes and behaviours while sick will make most diseases self limiting.

The most recent pandemic was H1N1, Spanish Flu in 1918-1920. Viruses are much harder to treat than bacteria since the dawn of antibiotics, mostly with a virus you treat the symptoms and wait it out. In the case of Spanish Flu it primarily killed the young fit and healthy, soldiers coming out of the war, killed effectively by immune overreaction. The spread can also be considered to be down to vast numbers of people on the move and living in close quarters who would not normally have done so (i.e. not during a war).
I'm not going to write out the various theories of how such an aggressive strain of the flu came into circulation, but given the existence of such a strain you'd have to find some way of spreading it rapidly before the dangers became known.
With current monitoring of causes of death for exactly the reason of preventing another pandemic, you'd have to have a war at least on the scale of the Korean War, with large numbers of troops manning front lines, coming from across the world to high density locations, with people flying in and out steadily. Otherwise it's going to be nasty but localised, covering no more than a few surrounding regions. See Ebola for reference.

At the end of the day, given modern medicine and behaviours, while you could still potentially manage a pandemic, it's unlikely something will get established the way the Black Death did.
Comment: "Consider a normal person with a severe illness. Most people in such a situation would call in sick and not go to work. Those who do go in are frowned on by colleagues for risking other people's health. You don't "man up" and go in regardless because that's antisocial." Unfortunately that's not really true (at least here in Austria, Engineering environment).
Comment: @JDlugosz I stand corrected. Apparently I had no clue of how HIV/AIDS worked, so I went full research mode and found that your're right. Note to self: next time check first!
Comment: I hope I'm wrong, but I think you're being overly optimistic here. For example, they knew to quarantine Flu sufferers (and had the guts to enforce it) back in 1918. We still had a pandemic so bad that 1/3 of the population caught it, and social structures started to break down in some places. Fast forward to today, when the same world is housing 5x as many people, and they are far more moble...
Comment: @T.E.D., I am fundamentally an optimist, but in this case I think that's reasonable as there wasn't a repeat of the pandemic after WWII which in theory offered exactly the same circumstances.
Comment: You don't consider HIV/AIDS to be a pandemic?
Comment: @JDługosz, technically yes. In practice it doesn't fit the requirements of the question any more than measles, TB or chlamydia would, as it's quite hard to get, compared to say Norovirus, where merely touching a contaminated surface without due caution can leave you in deep trouble for a week or more.
Comment: Not to mention the lethality of AIDS is not really high. It ussually depends on other infections/diseases to attack the host for it to be lethal. But a combination of airborn HIV/AIDS and, say, a flu, would be really deadly.
Comment: @tfrascaroli I thought that before recent advances it was 100% lethal.
Comment: Imagine something like HIV for chimps (SIV): if it infected Bonobos they would be driven extinct. The long infection time is an important factor.
Comment: @JDługosz, yes they would all die, but they would not die from AIDS itself, generally infected people die of secondary infections which are made that much worse by the lack of an immune system. It's one of those delightful medical statistics that goes with being cured of cancer. Cancer is in remission until such time as the person dies of something else without it recurring, at which point they're deemed to have been cured. No less dead though.
Comment: The biggest holes in the Canadian SARS quarantine were people who knew they were in a risk group but didn't feel they could afford to take time off work without pay.
Answer: Have you considered... influenza? The Flu is pretty good at killing people. Think that the deadliest one is still H1N1. So you would just need to engineer it to hide like helicobacter pyroli (so a virus that survive 36,6 temperature) so almost anyone would be carrier. And then design "starter" point in virus so it would start acting on a large amount of people at once (maybe something with temperature? with global warming the difference in temperature in Europe is much more rapidly than it was before).
Comment: I don't think it even needs human malice. Just random genetic recombination to create a flu virus that is deadly and highly infectious to humans, and highly infectious but not deadly in some common and globally distributed species of migratory birds.
Answer: The virus must defeat modern preventitive measures
There are a variety of modern protective measures against disease. These modern measures are first and foremost cultural. If you are sick, most people don't try to go to work and spread their diseases around. Either they loaf around at at home or go to the doctor. Since everyone knows how modern diseases spread (more or less), everyone can take simple sanitary actions. The Black Death today would be much less likely to spread, first and foremost due to the lack of rats, but secondly due to the natural instinct of the sick to self-quarantine.
To defeat our modern cultural anti-sickness measures, the disease would need to pick up some new tricks. The most potent would be to simulate a mild illness for a long period of time allowing it to spread.
Characteristics of this disease

The illness should cause symptoms of a mild runny nose and sneezing. People who had gotten ill would think that they had a common cold. It should not cause fevers at an early stage or many people will be alerted to its potential severity.
The illness must be contagious immediately. As soon as the sneezing starts, the disease should be able to spread.
The illness should be viable airborne. If the disease can make people sneeze, and can stay infectious in the air for some hours (or even days), it can spread the most other people.
The illness should take a long time to kill. Here is the key. Once a disease is known to have killed many people, it will be widely reported and cause a near panic. Just look at how many people are upset over Zika despite its relatively low fatality rate. The disease needs to take weeks or months to kill. That would allow it the time to spread around the world and infect as many people as possible before causing fatalities.
Comment: Zika doesn't really have a mortality rate, it causes deformities in babies as yet unconceived, even if it's only the father who is infected. Also infertility etc etc.
Comment: @Separatrix pandemic infertility and baby deformations might create a scary postapo world
Comment: @Separatrix That is kind of my point. There were NBA players who were worried about Zika at the Rio Olympics. I don't think they were pregnant.
Comment: @kingledion, I think you've misread my comment, there's a risk to the baby if the father is infected prior to conception, there's also a risk to the father's fertility. They're right to be worried. Think thalidomide but contagious, because even if that one person doesn't want to be parent they can transfer the disease back to the local mosquito population and affect everyone where they grew up. Yeah sure, the risk to the individual is low, but the overall risk is really quite high.
Answer: I already asked a question along these lines here: Is non-manmade pandemic a realistic threat to modern first world?
The general answer I got from all of them was no.  The major plagues spread so well in the past due to a lack of understanding of basic sanitation, our modern understanding of sanitation, quarantine, etc have made us much better at isolating and stopping the spread of disease.  Antibodies also prevent the spread due to germs and vaccines the spread of viruses.  While antibiotic immunity is an issue that would help a disease spread it's unlikely a disease would grow immune to all brands of antibiotics which are available at once, so antibiotics could a least be used to slow and limit the spread of the disease.
However, my original question was for natural viruses.  The is also the possibility of man mad disease.  I would suggest using a disease which was modified by man to make it more dangerous if you wanted a black plague scenario.  It could have been an intentional bio-weapon which got out of hand, or a disease which was released by accident.  However, adding the tweaking of humans could justify such things as how a disease developed an immunity to all known anti-biotics at once and thus justify it being a more lethal threat to society.
Answer: Black Death level diseases can only exist with a dispersed population or with a non-human reservoir, otherwise they burn themselves out and go extinct.
Since we no longer have an adequately dispersed population and no such killers are known that means something new.
Unfortunately, new diseases are all too possible due to mutations or species jumps.  Fortunately, such upstarts tend to start out not too infective as they haven't adapted to the human body well enough yet.
We had a close call with SARS which was no doubt such a scenario.  It hit in a place with sufficiently high tech medicine that it got pounced on and quarantined fast enough that it never developed the easy spreading that is required for a pandemic.  Fortunately, nobody who was infected flew to a place like Africa that lacks the ability to stomp on it.  It would have burned hot through the millions of Africans infected with HIV and by then it would likely be spreading better.
However, the really nasty scenario is when something that does spread well picks up lethal genes from somewhere.  The flu is notorious for exchanging genes and so it's a likely culprit for this.  Of course the disease hunters would see it and try to stomp on it but it spreads well enough quarantine would likely fail and vaccines take months.  Modern air travel is a nightmare for quarantine efforts.
If you want to take the threat up to 11 consider a madman who does this deliberately.  Instead of one patient zero you could have thousands.  Put dispensers in a bunch of airports and the chance of a quarantine is zero.
Edit:  Covid-19 and SARS are closely related.  This time it got the spreadability, very fortunately its nowhere near as lethal.
Answer: Yersinia Pestis, with a twist!
Considering the fact that this little germ has been responsible for many significant outbreaks throughout history (the black death among them), using this troublesome bacterium would be a good start.  If you want it to cripple modern civilization, not much has to be adjusted.
Antibiotic resistance
One of the things that makes Y. Pestis so deadly is the fact that it compromises immune function.  Combine that with a resistance to most (or all) antibiotics and faster transmission vectors(casual contact, airborne), and you have an essentially untreatable pathogen that will spread like wildfire.  Vaccines have been developed but aren't very effective and have some pretty nasty side effects, so they've fallen out of use for the most part.  So, even if they were to develop a vaccine, there simply wouldn't be enough time to manufacture and distribute before it's too late.
Comment: Its probable that the reason the European Plague epidemics became successively less severe and then stopped was a build-up of inherited resistance. It's therefore possible that Y. Pestis can no longer cause an epidemic amongst those of Eurasian descent. Especially so, since the frequency of flea-bites is greatly reduced in modern civilisation, and we know about using face-masks (and UV lamps and Ozone) if an airborne plague threatens. Observationally, there are no modern plague epidemics even in squalid ghettos where Y. Pestis is endemic to local rodents. Isolated human cases only.
Answer: Depending on how you want to utilize this pandemic, you could easily create a scenario with some sort of nanobots which gain a collective conscious. Prey by Michael Crichton has a similar premise.
If you are incorporating this into a story, it could be some level of AI like nanobot or otherwise be customized.
From the organic perspective, Executive Orders by Tom Clancy is insightful. Ebola is basically made airborn with a slower incubation period and released via aerosol cans at many conferences, resulting in it being quickly carried on airplanes around the world. This avoids some of the "problems" with a disease as dangerous as Ebola being too effective at killing its hosts, though within the novel this ultimately saves the United States.
Answer: How about an laboratory made viral transformation going out of control. A viral vector designed to increase productivity in farms that mutates out of control. It can produce cancer and death in a massive scale.
Answer: I suggest a viral pathogen, man-made, transmitted both thru bodily fluids and airborne (highly contagious). Then add a long incubation during which infected person APPEARS symptom-free but is contagious, then respiratory symptoms kick in, making patient more contagious. Make disease a retrovirus that can go dormant and reappear once treatment stops, make respiratory symptoms resemble a fatal pneumonia and Voila! Instant Catastrophe.
Answer: One interesting possibility to look at is the (possibly) coming Antibiotic Apocalypse.  Basically, certain antibiotics only work for so long before bacteria adapt to survive them.  The more an Antibiotic is used (say, on livestock, or when over prescribed), the faster it becomes obsolete.  We haven't run out of backup medicines yet, but if Antibiotic use keeps rapidly rising, and science starts running into barriers with regards to inventing new antibiotics, we could have a major problem.
At that point, even simple infections could cause death, surgeries would always be life threatening, and cuts would have the potential to kill.  Now, add in some new super-bacteria, and you may have a ballgame.
Answer: Virus have a good characteristic: antibiotics don't prevent those little bunch of atoms from spreading and doing their nasty thing.
Just make it easily transmissible (like airborne, not requiring blood and so on). With a death probability high enough (>60%) and that takes some time to fully develop (a month), while it's capable of transmission since day 0, and it'll spread a lot before being detected and producing deaths.
Also make the death occur from symptoms that are easily mistaken from something else, and you gain some weeks before someone thinks that a new kind of plague is happening.  For example, creating nodulus like a pancreatic cancer will make many patients go to a oncologist first, consuming time and not generating alarms from the first few days, nor special warnings about avoiding some kinds of contact.
And make it appear first in a crowded city, with many travelers, so that is spreads out fast enough since the first day.
Answer: If you want something that truly rivals black death you could create a more unique disease. One thing that immediately comes to mind is the issue of quarantining a disease (i.e. if nobody knows of it then it cannot be quaruntined). One thing you could do is make a disease with the symptoms of a normal cold. However, the symptoms start one month after exposure. Perhaps the disease lies dormant for some time and spreads itself whilst keeping immune system triggering damage to a minimum? Ultimately we want this disease to not be about affecting a body but rather infecting as much of the populous as possible. Furthermore, make the disease like rabies but not quite. We don't want zombies so instead cause people after 2 or 3 weeks of infection to somehow develop a compulsion to do something that infects other people. Perhaps make the disease cause a large amount of sneezing. Sneezing is less associated with illness so it's not going to be assumed as disease based but rather as allergy-related. Also, during this stage perhaps create compulsions of a need to be in social environments or something. Anything that could maximize exposure. Also, this disease should be about as contagious as bubonic plague (black death). Then it's pretty much guarunteed to spread amongst the masses. My guess. Within a month 60% of the world populous will be showing symptoms with the other 30% being infected. If you want to really make people spread this thing, have the virus or bacteria release adrenaline or other chemicals that make people feel not as sick as they truly are. Then at the 6th week drop all of those things like a rock by ceasing production which will result in an extreme crash of energy and then finally an unavoidable death as the virus/disease has by then obliterated the immune system (whilst temporarily replacing it to prevent suspicion).
Let me boil all of this down in a nutshell:
We want a disease whose primary method of attack is not brute force but rather deception. Therefore, it's plan of attack should be as follows:
Week 1: Spread throughout the body and replace as much of the immune system as possible. Work with the immune system if possible and have no tolerance for external diseases. Essentially replace the immune system.
Week 2: Continue a breakdown of natural systems whilst preventing overall detriment to the body. Produce sneezing and/or coughing as ways to spread the disease contagiously
Week 3-4: Attempt to produce chemicals and hormones to induce an intense need to be in public social environments as much as possible without appearing as a mental disorder. Use this to infect as many others as possible.
Week 5: Begin to show symptoms of some kind whether it be infections or whatever. Essentially test at breaking down systems of the body whilst not killing it (yet). Start producing hormones to fake higher energy levels to make the person feel better than they are. Raise these levels over time.
Week 6: Switch gears completely and start ripping the body to shreds. Work backwards to plummet the hormone levels to near nothing. Essentially cripple the person overnight. Fear is a tactic here. Make it seem worse than it is. Make people believe it appeared overnight and essentially ravaged EVERYTHING. Kill the bones completely. Ravage tissue. Make holes in the skin everywhere. Completely devour the internal organs. You've had six weeks to grow unimpeded. You are the immune system. You OWN the body and can consume it entirely near to the bone.
How would this disease occur? I would imagine it would bio-engineered and I think this would be a disease that could render man extinct. You basically have two months that this disease goes on before it reveals itself for the first time. That's a large time to be infecting others. Plus, it kills your immune system on day one. At that point, it is virtually incurable. It's got the force of an immune system disorder with the savageness of a foreign disease. Put those together and everyone is dead for sure.
Answer: I believe the gold standard civilization-killer is a bioengineered pox virus with a common animal reservoir.  Release it at a few big airports and in a week it's everywhere, just as the first victims start showing symptoms.
In an interesting twist, a killer mousepox (lethal to mice only) from 2001 was accidentally created during research on injectable contraceptives.  http://www.cidrap.umn.edu/news-perspective/2003/11/scientists-research-antidotes-super-mousepox-virus
Answer: COVID-21 (SARS-NCoV-2 x RHDV2)
While humans were busily fighting COVID-19 precautions, a little known virus called RHDV2 (rabbit hemorrhagic disease virus 2) took root in the United States, spreading from Arizona to Oregon and most places between.  It killed both rabbits and hares, and no one cared, though few have seen any coney lately that doesn't lay boiled chicken eggs in green plastic grass.  The CDC said it was not a hazard to human health.
Meanwhile, COVID viruses continued to mutate, occasionally undergoing a process of recombination in which the RNA-dependent RNA polymerase would dissociate from one virus it was copying, and begin copying another.  Mutations were combined from different strains.  Additionally, COVID, which had travelled the whole world, was in an excellent position to take up permanent endemic status in many mammalian species - cats, ferrets, horses ... and especially, rabbits.
What came next should not have surprised anyone.


Can I read the Tokyo Ghoul RE manga if I have watched the first 2 seasons of the anime?

Question: I have seen the first season of Tokyo Ghoul and a few episodes of Root A and I want to know if this is enough to read the Tokyo Ghoul RE manga. I have heard that Root A doesn't fit into the story of the manga, so should I watch it before I read RE or not? I'm also not sure if you can watch the first season of Tokyo Ghoul before RE, or do you have to read it in the manga?
Answer: Tokyo Ghoul: Root A heavily diverges from the original manga, which you've heard correctly. The first Tokyo Ghoul season does an okay job of covering its manga counterpart, but there are things that were skipped over or different. Since RE is the sequel to Tokyo Ghoul, if you go into it having only seen the two anime seasons, you'll be a little confused due to some of the plot points you'd have missed from the manga.
If you want to experience RE in full understanding, you might want to read the previous manga first. However, if you don't mind some confusion, it's ultimately up to you. Hope this helped!