vaccination - What is the efficacy of Pertussis booster vaccine among different age groups?

The Murray Microbiology book says that it is prefentially 10 years, similarly Estonian and Finnish health associations.

However, my professor says that it can be 5-7 years.

I started to think if the age is affecting here to the result.

When should you take booster vaccination of Pertussis if you are
a) 25 years old,
b) 50 years old,
c) 70 years old, and
d) 90 years old?

My professor says that there is no significant studies about the efficacy of Pertussis booster vaccination among different age groups.
Is this true?

evolution - What preceded ATP synthase?

ATP Synthase is ubiquitous throughout life on earth and so most probably evolved within the last universal common ancestor (LUCA) before that lineage diversified into the various kingdoms of life.

It is suggested that the functional domains comprising the ATP Synthase complex were cobbled together from pre-existing sub-units, each with with a related activity (e.g. the union of a proton motor with a DNA Helicase with ATPase activity), which seems reasonable, although a bit vague in the details.

The fact that a primitive ATP Synthase arose in the first place suggests that ATP already had a central role in cellular metabolism and so begs the question, what preceded ATP Synthase in the role of generating ATP in the LUCA cell?

Thanks in advance.

definitions - What is the difference between abiogenesis and spontaneous generation?

As we all should know, abiogenesis and spontaneous generation are far from identical. For one, spontaneous generation was disproven with Pasteur, and abiogenesis seems to be a solid scientific theory. However, one can loosely summarize both as "the emergence of life from non-living materials" which, at the very least, is confusing for the layman.

My question is: What truly differentiates abiogenesis from spontaneous generation? For example, if abiogenesis were to happen again, how would we differentiate the two terms?

Is time the most contributing factor (abiogenesis happened over hundreds of millions of years)? Or the fact that abiogenesis generates "primitive organisms", while spontaneous generation assumes the generation of evolved, complex organisms?

climate change - What are some possible causes that might explain why the global temperature has remained relatively constant in the last decade?

First - I do not know if this is the best site to pose this question. That said, this appears to be the most appropriate place post this question.

Consider this chart:

The chart was retrieved from here here.

I am curious as to whether anyone has any thoughts regarding this trend - note, however, that this is one chart among several that I came across on reputable site. All seem to depict this observed "capping" effect between roughly 2000 and 2010+. Unfortunately, I don't have much to offer right now since I am still looking into it.

Any input is appreciated.

biochemistry - What are the units of enzyme activity?

This refers to the turnover number (a.k.a k_cat or k₂) of an enzyme and is usually calculated using Michaelis-Menten kinetics. Jump to the summary at the end if you want a simple answer. If you want a more thorough answer, consider the following chemical equation:

[E] + [S] ⇌ [ES] → [E] + [P]

This says that a certain concentration of enzyme mixed with a certain concentration of substrate will first combine and form a complex depending on the enzyme's affinity for the substrate. Then the enzyme complex will generate a product depending on the enzyme's ability to convert the transition state into product. The k₁ constant is the arrow moving from [E] + [S] → [ES] and the k_-1 is the arrow moving from [ES] → [E] + [S] (they oppose each other). The k₂ constant is the arrow moving from [ES] → [E] + [P].

V_o = [ES]k₂

• V_o - this is the rate that product is being formed, which can be measured.


• [ES] - this is the concentration of enzyme-substrate complexes.


• k₂ - this is a constant value comparing the two.

This can also be expressed in terms of maximum rate:

V_max = [E]_Tk₂

• V_max - V_max is catalytic rate when [E]_T = [ES] (when all of the enzyme present is bound to substrate/saturated).


• [E]_T - [E]_T is the total enzyme concentration. [E]_T = [E] + [ES].


• k₂ - the k_cat is the catalytic constant. It is a constant indicating how quickly an enzyme can convert substrates into products. It is easily observed by this equation.

Summary

So k₂ is basically an indicator of how efficiently or quickly an enzyme operates. Not all enzymes follow standard Michaelis-Menten kinetics. For example, the allosteric properties of some enzymes cause a non-linear saturation curve. Because of this, the turnover number is commonly referred to. The turnover number's units of s^-1 indicate one product molecule per second, so a turnover rate of 3000 means you can create 3000 products in 1 second at V_max.

species identification - What is this marmot-like animal (Tigray, Ethiopia)?

I was searching what are the animals I frequently saw in the north of Ethiopia. I took some bad quality pictures.

For me it looked like a large squirrel, local people called it a rat, and on the internet I find rock hyraxes are quite frequent in the region, but they appear not to have a long tail like the animals I saw, and they don't have the white lateral line

cardiology - Calling for Free Online Data for Paediatric ECG?

I need free online data about heart murmurs to study these:

heart murmur frequency , S2 heart sound frequency and its split,
murmur timing, and duration, murmur intensity, S3 sound presence and
intensity, S1 presence and intensity, presence of ejection sounds and
arrhythmias

I will cite your source then if I can use your data freely.

I would really have the same data as used in this paper:

Heart energy signature spectrogram for cardiovascular diagnosis
Vladimir Kudriavtsev, Vladimir Polyshchuk and Douglas L Roy

No pediatric ECG data here

• beecardio (aggregation of many ECG databases)

Does anyone have simple data for my task?

I remember that some CD of some book has some standardised nicely organised sounds that you can use freely.

behaviour - Why is yawning contagious?

Yawning is contagious in humans, which means that, in general, it is more likely that a person yawning after perceived (by sight, hearing, or both directions) yawning issued by another person. The frequency of infection varies throughout the day, with a peak in early morning and late evening.

A recent study conducted by Ivan Norscia and Elisabetta Palagi (University of Pisa) has provided the first evidence that the behavioral contagion of yawning is associated with the empathic bond between people. The study showed that the infection follows the same gradient of empathy: is greatest in close relatives (parents / children / grandchildren, brothers, stable couples), decreases in friends, then acquaintances in (people connected only by a third, external, ie work or a friend in common) and reaches a minimum in the unknown.

Various studies of clinical, psychological and neurobiological suggest and support the link between the yawn contagion and empathy. For example, the infection begins to occur at 4-5 years of age, when children develop the ability to identify, in a proper way, the emotions of others. In addition, the infection is reduced or absent in people who have problems related to empathy, how people with autism, and is positively related to subjective scores of empathy based on tests of psychological type. Finally, the areas of the brain related to the emotional sphere overlap, in part, with those involved in the response to yawn, with a possible involvement of mirror neurons.

Yawning has been observed among various primates. In these cases the yawn is a threat gesture, a way of maintaining order in the primates' social structure. Specific studies were conducted on chimpanzees and stumptail macaques. A group of these animals was shown a video of other conspecifics yawning; both species yawned as well. This helps to partly confirm a yawn's "contagiousness".

In animals, yawning can serve as a warning signal. For example, Charles Darwin, in his book The Expression of the Emotions in Man and Animals, mentioned that baboons yawn to threaten their enemies, possibly by displaying large canine teeth.

see yawn

autism

Gordon Gallup, who hypothesizes that yawning may be a means of keeping the brain cool, also hypothesizes that "contagious" yawning may be a survival instinct inherited from our evolutionary past. "During human evolutionary history, when we were subject to predation and attacks by other groups, if everybody yawns in response to seeing someone yawn the whole group becomes much more vigilant and much better at being able to detect danger.

Personally, I can make an observation. Cats yawn as specific means to calm people, and especially to reassure the other cats and the pups. In order, they stretch, yawn, lie down, half close theyr eyes as if they start to sleep. When the whole group repeats the gestures, the majority of them (now calm) actually falls asleep.

EDIT @kmm

pharmacology - Is it better to take a half dose of paracetamol and a half dose of ibuprofen together rather than a full dose of either?

Whilst Alexander Galkin gives some great information, I think there's a fundamental reason why that particular pain relief strategy is best, and it hasn't been mentioned yet.

The reason is simply that when you take Ibuprofen or Paracetamol (a full dose) you can only take it once every 4 hours. However, the pain relief doesn't last for 4 hours, so if you take either or both together every four hours you will experience pain after the medication wears off and before you are allowed your next dose.

So instead you can follow either of two strategies:

1. Take a full dose of Paracetamol at 0 hours, 4 hours, 8 hours, as well as taking a full dose of Ibuprofen at 2 hours, 6 hours, 10 hours. This will give you less time when no pain medication is in effect. But if your pain is inflammation related you might want to keep the anti-inflammatory effects of Ibuprofen topped up, so you can...


2. Take a half dose of Paracetamol + a half dose of Ibruprofen every 2hours. This gives you a mix of pure pain relief and anti-inflammation and ensures minimum time when each medication has no effect.

I don't think human biology has to come into it (apart from the fact that you can take the two substances together with no ill effects), it's just a good pain-avoidance strategy.

zoology - Do any cells change in size or mass as mammals grow?

I'm wondering if it is safe to assume that the approximate number of cells per unit mass in a mammal will remain fairly constant throughout its lifespan.

Not exactly. When a tissue is put under stress, it can respond in four main ways:

1. Hypertrophy - individual cells get larger. E.g. stressed muscle cells get bigger.


2. Atrophy - invidivual cells get smaller. E.g. naturally in the thymus during development.


3. Hyperplasia - increased cell division to produce more cells. E.g. mammary gland cells in pregnancy


4. Metaplasia - one type of specialised cell is replaced with another, usually more durable one, E.g. columnar epithelium in the respiratory tract of a smoker being replaced with squamous epithelium.

The first three responses to stress can change both cell size (auxetic response) and number (multiplicative response), meaning you can't really say that cells per unit mass stays constant throughout life.

Muscle tissue grows predominantly by hypertrophy, meaning that the muscle gains during puberty are likely to be more as a result of cells getting larger than the development of new ones.

Both auxetic and multiplicative growth occurs as the body develops. In addition to this, accretionary growth also occurs - where connective tissues such as bone and cartilage increase in size.

genetics - Determination of gene direction

I'd first try translating it and looking to see if there are big regions that jump out at you that do not have stop codons in them. I normally use this tool for quick and dirty translations, it gives you all 6 reading frames. Also, you could just try BLASTXing your sequence if it is short enough. BLASTX translates your DNA in all 6 reading frames and will search the protein database for matching proteins. Most anything will have a hit in there, and if you get a hit it will show you the DNA sequence and reading frame that got translated. If your sequence is too big, break it down into smaller chunks until BLASTX works. One of your chunks will have your gene in it, and it will get a protein hit. You'll also need to break it up if you have two genes in one chunk, but you only get results for one of them because its longer and gives better hits.

human biology - What is the effect of garlic on intestinal flora?

From studies,

lactic acid bacteria were found to be more resistant to GP (garlic
powder) compared to the clostridial members of the gut microbiota.
While for most bacteria the antimicrobial effect was transient, the
lactobacilli showed a degree of resistance to garlic, indicating that
its consumption may favour the growth of these beneficial bacterial
species in the gut. Once the strains of other bacteria (eg:
Bacteroides ovatus, Bifidobacterium longum DSMZ 20090 and Clostridium
nexile A2-232) became resistant, they retained their resistant
phenotype upon sub-culturing. Garlic intake has the potential to
temporarily modulate the gut microbiota (reference).

Overall garlic can prove to be beneficial, because it seems to have more of an effect on detrimental bacteria like Helicobacter pylori (H. pylori), even when its strains were resistant to antibiotics. Overall garlic was found to be more detrimental to pathological bacteria when compared to normal gut flora (reference). Garlic’s diallyl disulfide has also been found to effectively cause cell death in Candida albicans which is a fungus in our gut which if not kept in check can cause health problems (reference).

Inulin and fructooligosaccharides present in garlic can also serve as nutrients for the probiotics colonizing your body (reference).

mammals - Do dolphins really sleep?

I'd say that unihemispheric sleep and adaptations like it really are sleep - the brain activity on one side of the brain gives a characteristic sleep pattern. It certainly must satisfy the needs of an aquatic mammal like a dolphin or a whale since they have to be partially conscious to breathe by surfacing regularly.

It does seem to affect the brain physiology, but is there a reason you would not call it sleep?

cellular respiration - Do cold blooded animals generate any heat?

They do generate heat. They just do not SPEND energy specifically on heating their bodies by raising their metabolisms. This is a form of energy conservation. The metabolic rate they need to live is not nearly enough to heat their bodies.

An example of spending energy to heat the body is seen in humans shivering. Here muscle is activated not for its usual purpose, but to function as a furnace. "Warm-blooded" and "cold-blooded" is somewhat a misnomer. The correct way to think of it is...

Endotherm or ectotherm. Does the heat primarily come from within (endo) or from the surroundings (ecto). Endothermic animals include mammals. Most of their body heat is generated by their own metabolisms. Ectothermic animals include reptiles and insects. They absorb most of their body heat from the surroundings. This is not the same as saying they let their body temperature fluctuate with their surroundings, some avoid this by moving around to accomodate themselves.

Homeotherm or poikilotherm. Homeotherms want to maintain homeostasis for their body temperatures. They don't want it to change. Poikilotherms do not exhibit this behaviour, instead their body temperatures vary greatly with the environment.

We can have endotherm poikilotherms, such as squirrels, who let their body temperature drop while hibernating. Endotherm homeotherms, such as humans, where temperature is constant by means of complex thermoregulation. Ectotherm homeotherms, such as snakes (moving into shadow or into the sun to regulate temperature), and ectotherm poikilotherms, such as maggots.

cell biology - Are there verbs for "undergo mitosis" and "undergo meiosis"?

From my experience on SE sites, I believe this is the right site to ask this question under "terminology".

I've been trying to find out whether English has one-word verbs for "undergo mitosis" and "undergo meiosis". I haven't been able to find confirmation on Google, but my linguistic imagination is limited, and I may have failed to google the right things.

Could you tell me if there are such verbs in common use in biology? I mean, if such verbs exist, can I find them in modern biology books or papers?