8
votes
1answer
154 views

Why do humans hear better between 2kHz and 5kHz?

I've recently seen the following image: Source: https://commons.wikimedia.org/wiki/File:Hoerflaeche.svg Translation (from German): The upper boundary (Schmerzgrenze) is where it starts to hurt ...
6
votes
1answer
81 views

Can anyone identify this chrysalis? (Identified)

It's about 5 or 6 cm long. It's on the outside (north facing) wall of my garage about a metre above ground level. Photo taken in Thailand near Hua Hin (about 12N 100E) in December 2014.
1
vote
1answer
43 views

Coniferous trees in temperare rain forests

In temperate rainforest, the dominant plant form is often coniferous trees (source). However, coniferous trees are also the dominant plant form in a very different climate and form a different biome ...
7
votes
2answers
108 views

Can the eye distinguish between pure and composite colours and how do we measure this?

Red light plus green light makes yellow light. Suppose I shone a pure red light, say 650nm, onto the same spot as a pure green light, say 550nm. The eye sees this two-peak spectrum as yellow. This ...
1
vote
1answer
50 views

Specialist evaluation for people aged under 40 years with stage 1 hypertension

Reading the NICE clinical guideline for Hypertension it says... For people aged under 40 years with stage 1 hypertension and no evidence of target organ damage, cardiovascular disease, renal ...
1
vote
1answer
92 views

Is there a rule for the annotation of the basepair or gene locus origin in bacterial genomes?

Since all bacteria have one circular chromosome, there is no designated origin to start the systematic gene locus numbering. Therefore, what is the rule to start the numbering at a particular point ...
1
vote
0answers
99 views

How do I import FASTA files into Haploview?

I'm trying to produce a haplotype network and so have decided to use the software haploview. However I'm having some problems importing my sequences into the software. I Have my sequences in a FASTA ...
3
votes
2answers
679 views

Action potential changes in low sodium concentrations but constant osmotic pressure

If I bathe a squid axon in a fluid that has high sodium concentration , why does the duration of action potential decrease compared to a control experiment in low sodium bath but maintained at the ...
1
vote
1answer
749 views

Deciduous trees in tropical rainforest

Some books says the dominant plant form in tropical rainforest biome is broad leaved evergreen trees. Other books say it is broad leaved evergreen trees and deciduous trees. What is the most accepted ...
3
votes
2answers
140 views

Choosing appropriate statistical test for ordinal data

Ordinal response variables show up often in biology, but I'm not sure how they are best analysed. Some examples are qualitative assessments (little, many, a lot) or risk assessments (low risk, medium ...
9
votes
1answer
479 views

Mass spectrometry versus western blotting for validation

I have mass spectrometry data (LC-MS/MS) from rat cortices under either drug or control treatments. The results were performed in triplicate (three pairs of rats, drug or control per pair). In ...
3
votes
1answer
773 views

What is the purpose of segments in citrus fruit?

What is the purpose of segments in citrus fruit? In my experience, each segment usually contains from zero to two seeds. I may have seen more but only rarely, if I remember correctly. What is the ...
8
votes
3answers
270 views

Evolution: One big population vs. many small populations

Let's say I want to evolve a bacterium that is resistant to an antibiotic. I want to do this by growing initially clonal populations of bacteria in presence of this antibiotic for a long time. I have ...
2
votes
1answer
196 views

G>T transversion VS. T>G transversion?

So I'm reading about how mutations in DNA can be caused by oxidative damage. An example of a product of oxidative damage is given: 8-oxo-7-hydrodeoxyguanosine My textbook says that this product ...
7
votes
3answers
1k views

What is the science behind the inaccurate perception of colors?

If I go into a green room (all walls are semitransparent and green) and spend some time - around 10+ min - in there, when I come out all my eyes see is white as pink. I see no (or very few other) ...
11
votes
2answers
213 views

Is there any evolutionary advantage of selection of L-amino acid over D-amino acid?

After listening to a scientific talk, I had this question that why in the natural selection process, are the L-amino acids selected over the D- form. However, we still we produce D-amino acids; ...
3
votes
1answer
114 views

Specific location where nerves converge

I'm looking for the "earliest" specific site where the 3 following nerves' sensory signals "converge": Trigeminal nerve Median nerve Superficial peroneal nerve By "earliest", I really mean the ...
2
votes
0answers
60 views

Are the Chromosomes organized in any meaningful way? [closed]

So my major is in pharmacy but both my master and my (currently in progress) doctoral degree are both in theoretical chemistry. My thesis is about quantum chemistry and proteins, but it has a certain ...
4
votes
1answer
55 views

What is the biggest facultative anaerobic metazoan known to science?

Related: What's the biggest obligate anaerobic organism discovered till now? I had always assumed that the Riftia tube worms were obligately anaerobic since they lived next to anoxic volcanic ...
-3
votes
1answer
1k views

Are transgenders born physically different from others?

Are all children born with only either male or female body parts (other than exceptions), or is there actually a natural third gender with the physical characteristics of both genders, e.g. the child ...
3
votes
1answer
732 views

Names of nerves in hands, shins and face

I am looking for the names of the nerves in 3 specific locations of the human body: The nerve running along the "top" (opposite side of the palm) portion of the thumb, from knuckle to fingernail ...
0
votes
1answer
44 views

Spironolactone's role with adrenergic agents in heart failure?

I am studying the treatment plan of adrenergic agents for heart failure. Then, in the group discussion, spironolactone was included. But I cannot understand how it is relevant when considering ...
7
votes
2answers
207 views

What does pain look like in wave form?

I am interested in understanding what "pain" and "hot/cold" look like, as far as waves signatures (signal processing) go. My general understanding of how pain (nociceptive pathways) and hot/cold ...
4
votes
1answer
1k views

Why are irises unique?

I heard that irises are different and unique for every person. According this link, probability of two irises having identical pattern is 1 in 10 to the 78th power. That's how iris scanners identify ...
0
votes
2answers
142 views

Binding of Multivalent Antibody to mutiple epitopes?

A multivalent antibody molecule such as Immunoglobulin M Immunoglobulin A etc bind to more than one antigens or epitopes but I am confused about that wheather these multivalent antibodies bind to ...
3
votes
1answer
31 views

Regarding tumors and their developement

If certain cells or tissue in a specific part of the body are for some reason overworked; like the cases of severe acid reflux damaging the throat repeatedly and the cells in the throat having to do ...
2
votes
2answers
4k views

Can I drink warm/hot tap water? [closed]

I live in Canada and tap water is drinkable, as a matter of fact, the government puts a little bit of flouride in the tap water so it cleans your teeth. My wife and mom always tells me not to drink ...
8
votes
1answer
356 views

Single long axon vs serial neurons

Based on the comments in this post and also this chat. For discussions and speculations please comment in the chat. The basic question is what is the advantage of having a single long axon such as ...
2
votes
0answers
41 views

How do I get recombinant proteins into the nucleus of mammal cells?

I know that there are Nuclear Localisation Sequencenes (NLS). They can be taken from endogenous or viral proteins and fused to the N or C terminus of my recombinant protein. Which is the best one? ...
1
vote
0answers
47 views

How do PER/CRY complexes accumulate in the cytoplasm?

The Period/Cryptochrome (PER/CRY) complex is a heterodimer that transcriptionally regulates circadian rhythm. When it is phosphorylated, it is transported to the nucleus and it inhibits a ...
2
votes
1answer
2k views

Nerves, Neurons, Axons and Dendrites by Example

Here is a simple diagram of a neuron: A few (very closely related) questions: Where are receptors located (for pain, pressure, temperature, etc.): in the axon terminals or the dendrite tree? ...
3
votes
1answer
121 views

How can I purify RNA after gel electrophoresis to remove residual acrylamide?

I sometimes use denaturing gel electrophoresis on a preparative scale to purify RNA produced by in vitro transcription. The major issue with this is that the sample after extraction from the gel still ...
2
votes
0answers
1k views

Physiologically, how can stress/anxiety cause neuropathy?

According to the Mayo Clinic, stress/anxiety can cause "pins and needles" (neuropathy) sensations all over the body. But how can this be? My understanding of the sensory pathway is that sensory ...
4
votes
1answer
137 views

Is it possible to dock multiple ligands with the target?

Is it possible to dock multiple ligands with a target? If so, what is the suitable software used for? -- Is it possible to fix specific docking region for the target (or) automatic?
0
votes
1answer
59 views

Satisfication with irrelevant things [closed]

I am not sure if this question is better suited CogSci.SE so please tell me. My question is why are we satisfied when we get things that aren't useful in any important way? For example, relating to ...
1
vote
1answer
202 views

Can signals travel “backwards” in the sensory pathway?

My understanding of the "sensory pathway" is that its a linear, directional pipeline as follows: Nerves (fire various signals depending on the type of sensors they are) Fibers (transmit signals from ...
2
votes
1answer
101 views

Fab fragments of antibodies to fight viral infections

I was reading about Fab fragment and about using them to fight of viral infections. It seems that the Fab attaches to the viral receptors, which stops the viruses from attacking the cells. It seems ...
24
votes
3answers
2k views

Hot water and bacteria

I know that it is common to say, "use hot water when washing your hands" or when you've got a cut, "wash your hands with warm water," etc. I was wondering, why is this the case? Since bacteria grow in ...
1
vote
0answers
46 views

Persistency of botulinum toxin in environment

There is information about decontamination times here on pages 6 and 7. My specific question is how persistent botulinum toxin is in a natural environment, or alternatively, what is the half life of ...
0
votes
1answer
32 views

Cells scatter light in solution. Do they refract?

For part of an exam question, "why do cells grown in liquid cause turbidity?" I answered that cells refract light. The correct answer was that cells scatter light. Isn't the light scattering ...
3
votes
1answer
78 views

Why do some animals try to imitate other animals?

There is a tendency of some animals (including people!) to be "copy-cats" and try to imitate members of their own, and sometimes other, species. The most obvious example is a parrot copying human ...
-1
votes
1answer
80 views

What is the evolutionary purpose of white spots in nails and how can they be characterised due to Leukonychia? [closed]

Suppose you haven't hit your nails so the white spots are due to Leukonychia. Are the discoloration i.e. the white spots due to lower porosity (less minerals absorbing) or some other factor? I ...
5
votes
1answer
254 views

Western blotting with multiple antibodies

Normally I wash/detect with one primary/secondary-HRP antibody pair, strip, then wash/detect with the other primary/secondary-HRP pair which works well. However, I recently started working with a ...
2
votes
1answer
76 views

Anatomy of nervous system's sensory pathways

When I touch my hand on a hot stove, I feel pain. I'm interested in knowing all the main "endpoints" (components/parts of the body) that are involved in relaying this pain signal. As I understand it ...
1
vote
1answer
58 views

How and where do nerves share pathways to the brain?

I am interested in understanding how pain receptors send signals to the somatosensory cortex (the part of the brain that registers various nerve signals such as pain, presure, temperatures, etc). ...
1
vote
1answer
6k views

Why do the major and minor groove exist in DNA?

So I know that the major/minor groove arise from the offset pairing of the two strands in the helix. All my textbook tells me is that "pitch causes the off-set pairing of DNA and this gives rise to ...
0
votes
1answer
38 views

What does 'pedigree information' mean?

This paper uses Pied Flycatcher as a study species. For the population of Pied Flycatchers they studied, 'pedigree information' was available. What exactly does this 'pedigree information' mean?
10
votes
3answers
1k views

Do snakes get dizzy?

I've seen snakes get captured in sacks and I've wondered if the snake would get dizzy if the sack were twirled around. I have not done any tests (and don't plan to) because snakes scare me.
1
vote
0answers
30 views

Would blue light be effective to help average people when sunsets come much earlier in the day?

I know people with SAD (Seasonal Affective Disorder) benefit from blue light in the winter as night-time comes much earlier (in the UK, sunset is around 4pm in December, compared to 9pm in June). ...
2
votes
1answer
103 views

Do distinctions between dry, tickly and chesty coughs have any medical basis?

Background At least in Britain you normally come across distinct kinds of cough medicine "chesty", "dry" and "tickly". Questions Are "chesty", "dry" and "tickly" coughs always due to ...

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