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Cells, Microbes & Viruses / Re: Could a virus or bacterium survive inside a rock?

« on: 23/03/2018 10:24:53 »

But the Desulforudis bacterium was found in a deep gold mine

Pursuant to Evan's post, this is me down a gold mine in South Africa looking for long-lost microbial life!

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Cells, Microbes & Viruses / Re: Could a virus or bacterium survive inside a rock?

« on: 23/03/2018 10:22:32 »

This is a really nice interview about extreme bacteria surviving in the Atacama desert and the prospects for life on Mars. It's pertinent to this discussion.

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Cells, Microbes & Viruses / Re: Could a virus or bacterium survive inside a rock?

« on: 23/03/2018 09:43:23 »

spent thousands of years protected inside this rock in a dormant form, finally be released into the environment when the rock breaks apart (erodes, falls off the side of a cliff, earthquake etc.) and go on to infect a new host?

This is certainly a concern as the tundra melts - it may release new strains of disease organism that have been frozen for thousands of years.

Would it be possible for a particularly hardy pathogen to land on some sediment, become incorporated into the rock

It is unlikely that a surface-dwelling bacterium could be incorporated in rock, and continue living - the change in environment is just too great. Living things require an ecosystem in which to live, and an ecosystem would not survive such a major change.

In tough times, some bacteria (and larger creatures like tardigrades) can go into a dormant state, and then resume growth when the necessary ingredients return - water, food, temperature, oxygen (or lack of oxygen), etc.

But the Desulforudis bacterium was found in a deep gold mine
- It is found as a monoculture, ie it is its own ecosystem.
- It lives and grows in rocks, using energy from the radioactive decay of elements in the rock.
- The fact that it is killed by oxygen suggests that it is not a surface bacterium that got buried, but perhaps one that has been living out its whole existence in deep rocks. (For comparison, some anaerobic bacteria in our gut can produce spores that survive exposure to oxygen.)
See: https://en.wikipedia.org/wiki/Desulforudis

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Physiology & Medicine / Re: Does dietary protein affect kidney function?

« on: 18/07/2017 08:19:05 »

Dietary supplements never harms kidney. If still worried about it that you can also take advice from dietitian. 

Never say never in medicine. "Safe" supplements may do no harm, but some supplements may be contaminated, or just untested, and have harmful health side effects.

To address the original question being asked, dietary proteins will not affect a healthy kidney.

However, a person with renal failure owing to kidney disease can have serious problems with dietary protein. This is because the kidney provides the normal route out of the body for disposal of nitrogenous waste. This comes from breaking down or "deaminating" the amino acids in proteins, and most of it is lost as urea in the urine.

Renal failure can lead to an accumulation of nitrogen compounds, which can have a range of health impacts. Patients with renal disease therefore have to be careful about their dietary protein burden.

This should not be confused with the proteinuria (protein in the urine) detected under certain conditions. Damage to the kidney, such as chronic hypertension (high blood pressure) or diabetes, can affect the ability of the kidney to selectively repel the proteins in blood; this results in some of the proteins being filtered into the urine, where they are detectable with a dip-stick test.

In this instance, however, the proteins are a consequence rather than a cause of kidney disease.

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General Science / Re: What are we going to do to the inhabitants when we find another planet?

« on: 29/05/2017 08:31:31 »

1. Eliminate the small ones with insecticide

2. Turn the big ones into alcoholics

3. Give them influenza and syphilis

4. Teach them religion so they kill each other

5. Appropriate their resources (why else would we have gone there in the first place?) 

6. Apologise

The best thing that can happen to the universe is that humans stay on this planet.

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Plant Sciences, Zoology & Evolution / Re: Why do birds stand on one leg when they rest and sleep?

« on: 25/05/2017 12:25:43 »

Right on cue, this paper has an answer:

http://rsbl.royalsocietypublishing.org/content/13/5/20160948
 

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General Science / Re: Why do I get stuck trying to dodge another pedestrian?

« on: 12/05/2017 00:01:13 »

This is such a fantastic question; I think we need to look into this more deeply because I think there is something interesting going on with this. It also happens to me quite frequently!

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General Science / Re: Why do I get stuck trying to dodge another pedestrian?

« on: 11/05/2017 10:00:34 »

Possibly a "goalkeeper reflex" is at work here. As soon as we detect the eye movement that precedes a body swerve, our first instinct is to move in that direction, defending our territory. At short range this can, as intended, lead to a collision.  I used to coach a brilliant junior fly-half who could break through a defensive line by looking left and running right. The trick of avoidance is to signal your intention as early as possible.

To avoid embarrassment in a pedestrian collision, always apologise in German. If the other bloke is German he will realise that you aren't, but will be so impressed with your social skills that he won't complain. If he isn't German, he will assume that you are, and not attempt to complain in English.

German goalkeepers, on the other hand, are a problem.

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Plant Sciences, Zoology & Evolution / Re: Do animals have weird dreams?

« on: 08/05/2017 16:48:00 »

Hi Ries,

as SquarishTriangle already pointed out, it is of course difficult to impossible to determine what an animal dreams. At least at the moment, it would be impossible to know what other people dream, if they would not be able to tell us about it.

From my annecdotal experience and a very anthropocentric point of view I believe that at least dogs do dream, and I would guess, that they also have very engaging dreams. I crew up with dogs and especially our first dog used to have quite intense situations during sleep involving running movements, snarling, growling, rapid eye movements, fawning, gasping and slight forms of barking regularly. In one case she even howeld like a wolf, a sound I never heard from her before or after that dream again. That was super weird and I swear (anthropomophizingly of course :-)) she had a very confused look in her face when we woke her up from this. Our other dogs also show some of those mentioned signs that would lead me to think that they dream.

However, this is purely annecdotal, even if many other pet owners can add their own stories to this.

Science also tried to tackle that question, if animals do dream at all.
We know from comparing EEG patterns of sleeping animals that many mammals and birds follow similar sleep patterns like humans with deep REM sleep phases alternating with lighter non-REM sleep phases. In humans the REM phases are the ones were we dream and it has been shown, that they are essential for memorizing.

The movements during sleep is one of the best observable hints we have for actual dreaming. There is a sleeping disorder in humans, where muscles will not be paralysed during REM-sleep, so that dreams get acted out by walking, punching, kicking..  This disorder exists also in domestic animals, suggesting that they do dream as well (you can finde videos of such animals if you search for REM sleep disorder in animals). Scientists also induced this disorder artificially to study cats during sleep in the 1960s, observing those animals acting out during REM-sleep, including walking an dfighting invisible opponents.
Some more studies are done on brain activity during sleep, showing in rats, that they relive their daily experiences and in zebra finches, that they memorize their bird songs during REM sleep.

So there is quite some behavioural and neurologcal evidence for animal dreams. Given the nature of dreams from our human experience, there is so far no reason to believe, that animals would exclusively dream of "normal" things, althought their "weird" might be something completely different from what we would expect it to be. However, in the end nobody knows and it might be impossible to ever know.

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Plant Sciences, Zoology & Evolution / Re: Is it true puppies get the best out of both parent's genes?

« on: 22/04/2017 15:47:12 »

Can agree to the pavement special being the best, generally the sortaterrier is a good indoor dog, and the sortador is a good yard dog. They are sort of like a terrior and a labrador in each case, just they are close to a generalised nondescript brown mostly dog. Best you can get.

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Plant Sciences, Zoology & Evolution / Re: Is it true puppies get the best out of both parent's genes?

« on: 22/04/2017 12:46:22 »

As Atrox pointed out, it all depends on what breeders consider the best traits. Often this is based on superficial things, which characterize a breed, often leading to puppies who may have future medical problems. In the USA, the German Shepherd is bred to have a low rider hind end. This may look cool to the GS enthusiast, but it often leads to hip problems later in life. If you bred to remove the hip problems, this may change the style of the dog. They may get smaller and become more square.

The healthiest dogs, which are not always the prettiest, are often the mutts. The mutts form when you allow the dogs to decide which are the best features of the parents. Dogs tend to pick things such as good health, and will often sacrifice shallow looks. The mutts tend to converge dogs breeds back to a center.

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Plant Sciences, Zoology & Evolution / Re: Is it true puppies get the best out of both parent's genes?

« on: 22/04/2017 11:38:44 »

Hi Alan,

short answer: No... although it of course depends already on what someone would judge as "the best" in a parent. For example a breeder might rank some traits as favourable (e.g. coloration, a certain figure, short nose, hairstructure and so on) than someone with a medical backround would rank as bad (for example a short nose could make it more difficult for the animal to breath and should therefore not be desirable).

But even if we just consider the opinion of one person, it is not always the traits this person desires the most that will be passed on more likely.

For the longer answer, the basis for understanding what is going in the inheritance of traits are the Mendelian Laws of inheritance.
They basically say

a) In the genes each trait is coded for with two alleles, that migh look like this: Aa. When the trait gets passed on, the two alleles will separate into A and a and will recombine with the two alleles of this trait in the partner. So you will always have one allele of the mother and one of the father in the offspring to code for a trait. In this visualization the big letter is coding for a dominant allele, meaning that in a combination with a recessive allele the dominant one will be the one that gets expressed. The small letter is a recessive allele, meaning it is the one that gets supressed in a combination.

b) If the parents have a pure genetic backround for a certain trait (homogenous), for example the mother is a white dog (ww) and the father is a black dog (BB), then the emerging offspring will all be heterogenous (means, a trait is now not "purely" coded for anymore) and will all be the same. In this example alleles expressing "white" are recessive (small w) and alleles expressing black are dominant (big B). Therefore in this case all the emerging puppies would be black as all the new recombined alleles would look like this: Bw (B from the father and w from the mother). This kind of heredity is therefore called dominant-recessive. There is another possibility where the alleles from the mother have the same rank as the alleles from the father, so the offspring would for example look like this: BW .. in this case neither black nor white is dominant, so the offspring would possibly be grey. This is called intermediate heredity. So if the person ranking the traits would like to have white dogs, it would not be very happy with both scenarios.

3) However, you can get white dogs from this offspring again with a certain probability. If you now mate two individuals with heterogenous backround (Bw) you will now get offspring that might differ from each other quite a lot. All possible recombinations would now be those: BB (black dog, homogenous), Bw (black dog, heterogenous), ww (white dog, homogenous). Due to probability, the chance to get a white dog is only 1/4, as is for getting a homogenous balck dog. About half of the offspring will still be heterogenous and thus, while you would be sure that mating white dogs with each other would always produce white dogs, it is still difficult to say what offspring you would get in the next round if you use the black ones.

This is a simplified model, where one trait is coded for by just one allele. In reality traits are often coded for by several alleles and some alleles are responsible for several traits, making the whole thing a bit more complex.

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Plant Sciences, Zoology & Evolution / Re: How is frogspawn fertilised?

« on: 17/04/2017 11:09:56 »

But surely the biggest, burliest male is the "best" parent because he's strong enough to have fought off the competition and protected his female during the mating period?

Additionally to what SquarishTriangle said: it is not always the strongest and best suited male that win the price. In some species smaller and less competitive males might go for another strategy. Instead of directly competing with bigger (e.g. usually louder if display is based on vocalization) male they wait nearby in silence until a female got attracted by the lovely sound the big male produces. The smaller satelite male will then try to intercept the female and trick her to get into the amplexus. Once in this position the smaller male has an advantage over otherwise maybe more competitive males.

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General Science / Re: Should we ban pit bulls?

« on: 17/04/2017 07:50:02 »

They used to exist here, but it was finally realised that so few actually paid for them, plus the number of council employees that were there to enforce it, was costing many thousands of times more than the money coming in, plus it did not serve a purpose at all, so it was finally removed. There only exists a raft of laws about dog and cat inoculations and kerb laws, most of which typically are never enforced.

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General Science / Re: Should we ban pit bulls?

« on: 16/04/2017 17:05:06 »

Definition of a dog: an animal that can bite your arm off, but generally choses not to.

I'm all in favour of the reintroduction of dog licenses, which were compulsory in the UK in my youth. An irresponsible owner could have his licence revoked, and with the advent of compulsory chipping, any dog not chipped or whose chip was not traceable to a licensed owner would be eligible for adoption or destruction.

No compunction about destruction of any demonstrably dangerous dog, regardless of breed, unless its licensed owner was  a police or military unit and the animal was under control until deployed as a legitimate weapon. Anyone else attempting to buy a potentially lethal dog or gun must declare on his licence application who he intends to kill with it. Ban the intentional breeding of deformed or unstable animals.

I've always had dogs around as companions, or as a puppy walker for a guide dog, but always dog-shaped (long nose, deep chest, long legs) mongrels or "working" gundogs. Anything else is surely a sad statement of the owner's psychological  problems. And despite selecting calm pups and socialising them according to the guide dog and gun dog training manuals, I've never left a dog of any age or size alone with a child under 10 years old.     

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General Science / Re: Should we ban pit bulls?

« on: 16/04/2017 12:27:12 »

@SquarishTriangle - Thanks for the thorough answer.

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Plant Sciences, Zoology & Evolution / Re: How is frogspawn fertilised?

« on: 16/04/2017 11:58:19 »

Yes, exactly.
However, it has been found that in cases where frogs reproduce in one big mating bout all at once (e.g. Rana species) a females eggs are not seldom (up to more then 50% of egg clutches) fertilized by more than one male. In those mating systems where they release eggs and sperm in the open water (also in many fish) it is very difficult for the male to ensure exclusive paternity, especially if they are explosive breeders, that spawn in maybe only a few hours. It has been argued due to the fact that the sperm concentration of the water is very high during those hours it is likely, that sperm of other males can reach also other eggs produced by females nearby. But with behaviours like the amplexus in many amphibians the male can significantly increase its chances of fertilizing most of the females eggs.

Ensuring paternity is often easier with internal fertilization.. but not as a general rule. In many internally fertilized species multiple paternities are still common due to females mating with multiple males, resulting in sperm competition, cryptic female choice or even males having evolveld certain active strategies like clearing out the spermatheca where the female stores sperm before ejaculating or sealing up the females genitalia to prevent other males from mating with her or simply guarding her for the same reason. Reproduction is a war! :-)

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Plant Sciences, Zoology & Evolution / Re: How is frogspawn fertilised?

« on: 16/04/2017 11:13:16 »

As many frogs are externally fertilized the fact that the sperm finds the egg can be especially remarkable. For the male, to ensure to fertilize as many eggs as possible, it is essential to release its sperm very close to the females cloaca when she is laying her eggs, as frog sperm is typically not very mobile. Those frogs one would typically observe in mating in large numbers in ponds or other water bodies usually produce a large amount of sperm to ensure at least some to find the eggs. The egg cell is releasing certain proteins to attract the sperm cells and is then binding the sperm cells with the help of another protein that is conained in the egg jelly. The sperm has then to find its way trough the jelly to the egg cell to be actually able to fertilize it. It has been shown, that sperm cells that are motile but swim slowly and steadily are more successfull in reaching the egg in the end than fast but unsteadily swimming sperm cells. Those often get trapped in the jelly and never make its way trough to the actual egg cell.
SquarishTriangle descriped pretty nicely how it goes on from there for the sperm cells, that actually made its way.

all the best