12
votes
0answers
109 views

Haidinger's brush: Is this a by-product of the eye's physics, or are there any evolutionary grounds for it?

The human eye is, very subtly, sensitive to the polarization of light. This is an effect known as Haidinger's brush (see Wikipedia article of this name). What, if anything, is known or at least ...
11
votes
0answers
60 views

Beginning of the urogenital system

Are any invertebrate nephridia (proto/meta) homologous with vertebrate kidneys in the sense that embryologically they also begin together with the genital system? When did the embryologic association ...
9
votes
0answers
131 views

paralogue genes in genome-wide association studies?

Has anybody tested if paralogous genes are over-represented among the genes identified by genome-wide association studies (GWAS)? For example, if a GWAS study finds 200 genes associated to the ...
8
votes
0answers
112 views

How reversible is DAT upregulation from long-term ADHD medication use?

A mechanism for ADHD stimulant medication tolerance has now been found. See http://neurosciencenews.com/adhd-medication-patient-brains-adapt-dat/. Here's the thing though: what exactly is the ...
6
votes
0answers
120 views

Birds placing sticks on train tracks?

I live in a semi-rural area in Germany, close to a park which trains go through every 20 minutes. Today, I saw something that left me perplexed. There is a large population of birds that look like ...
6
votes
0answers
63 views

Using the IMGT/GENE-DB service to find RSS

I'm trying to get the data for the Human and Mouse 12 and 23 Recomination Signal Sequences (RSS), to run a classification algorithm on it. I'm not a biologist, so I apologise in advance for my ...
6
votes
0answers
123 views

What is the fastest way to build an alanine scanning library?

For interfacial studies, I would like to build an alanine scanning library for one of my proteins examining 20 sites. I will ultimately express the gene using E.coli cell-free protein synthesis. I ...
6
votes
0answers
77 views

Pancretic Acinar Cell - ATP, calcium concentration data

I need to find a decent source of data for concentration of ATP and calcium in the pancreatic acinar cell. So far all I can find is ATP or calcium 'levels' based on fluorescence , which are not ...
5
votes
0answers
59 views

How can flies sense mirrors?

I've noted that flies in my house have no problem landing on even perfectly clean mirrors. Why don't they fly straight into them? Can they sense that there is a surface there, even though they can't ...
5
votes
0answers
47 views

Why does ant queen keep the eggs out of her hive?

I have captured an ant queen and now I'm trying to create an artificial ant nest. I have noticed that though she has dug a hole to hide in, she keeps the eggs out of it unless she feels that they ...
5
votes
0answers
42 views

Is it possible to combine live attenuated and non-live vaccines?

There are many combination vaccines available but I've noticed that there don't seem to be any with both live and non-live components, e.g. DTaP/IPV/MMR. Such combinations could be useful in some ...
5
votes
0answers
45 views

E coli cotransformation efficiency

What is the E coli transformation efficiency for 2 plasmids? Are any studies that have looked at the correlation between number of plasmids transformed and transformation efficiency? Is there a ...
5
votes
0answers
72 views

Neuroendocrinal mechanism of parturition

My book reads, "The fetus signals that it is mature by secreting certain hormones that diffuse across the placenta into mother's blood and cause the secretion of oxytocin from her posterior ...
5
votes
0answers
129 views

Cytoplasmic determinants - protostomes and deuterostomes

Cytoplasmic determinants are spread unevenly in the egg, and so when embryo starts forming (cells start dividing), the determinants are also unequally divided between cell. This unequal distribution ...
5
votes
0answers
222 views

Reason for seeing grid-like patterns when strobing a solid black-white image?

I was trying to do some stimulation for SSVEPs by strobing a solid black square and a solid white square. Weird thing was, I ended up seeing weird grid like patterns that looked like this, always of ...
5
votes
0answers
166 views

Do non-human animals suffer from insomnia?

And how do we know whether they do or not? § If sleep is a physiological need, it seems weird that we become unable to fulfill on demand even in the absence of any obvious physical issues. We would ...
5
votes
0answers
104 views

What temperature should mammalian B-Cells be stored at outside of the incubator?

I'm working with murine B-cells. The general protocol is to keep cells on ice to keep them from dying but I've noticed that it makes these cells aggregate and precipitate out. I've heard suggestions ...
5
votes
0answers
49 views

Providing small molecules to cells on a filter plate

Lets imagine that I have mammalian cells that I've immobilized on a filter. Now I want to keep providing small molecules to these immobilized cells without resolubilizing the cells. The caveat is ...
4
votes
0answers
15 views

How does MSMA kill crabgrass with only minimal damage to lawn grasses?

I use MSMA (Monosodium methyl arsenate) to kill crabgrass in lawns. I am not certain of the mode of action. How does this chemical work? How does it target the annual grassy weeds, without damaging ...
4
votes
0answers
19 views

Why doesn't Clopyralid damage cool season lawn grasses?

I use Clopyralid (3,6-dichloro-2-pyridinecarboxilic acid) to kill broad leaved weeds in lawns. From my understanding, it works by mimicking an auxin which affects plant growth. Naturally this pulls ...
4
votes
0answers
20 views

How does Sodium Valproate cause neural plasticity

I have been reading a fascinating paper: Valproate reopens critical-period learning of absolute pitch 18 individuals were given Sodium Valproate (VPA) for a fortnight during which they trained on a ...
4
votes
0answers
29 views

How does the frequency of a visual stimulus affect the steady-state visually evoked potential?

I want to make a project for EEG signal processing, and in my research I found the concept of SSVEP, which means that if you have a stimulus with low frequency applied to the eye, the electrical ...
4
votes
0answers
58 views

Help Needed Identifying Corvids

I'd appreciate some help identifying these three corvids I photographed in Austria during the Summer: I know identifying corvids can be difficult, I'm not an ornithologist, just an amateur bird ...
4
votes
0answers
36 views

How does a Na+/H+ antiporter drive osmosis in this “osmotic motor”?

This recent paper in Cell describes a cancer cell using osmotic pressure to move in confined spaces. The cell preferentially inserts Na+/H+ antiporters in the leading membrane. I want someone to ...
4
votes
0answers
82 views

Comment on the introduction to a bioinformatics paper

I've written a paper about DNA sequence analysis. This paper attempts to use Bayesian modelling for a set of DNA sequences. It will probably end up either in a statistics journal, or, more likely, in ...
4
votes
0answers
27 views

Linkage disequilibrium with $n_l$ loci $n_a$ alleles

Linkage disequilibrium $\left(D\right)$ for two bi-allelic loci is defined as: $$D=X_{11}X_{22} - X_{12}X_{21}$$ , where $X_{11}$, $X_{12}$, $X_{21}$, X$_{22}$ are the frequencies of the haplotypes ...
4
votes
0answers
41 views

Are recessive, deleterious alleles less common on the X chromosome than the autosomes in humans?

Because there's potential for them to be more readily purged in hemizygous males (and in cell lineages in females with the deleterious-allele-bearing chromosome activated), I would expect the ...
4
votes
0answers
115 views

How many loci explain 50%, 80%, 99%, … of the total genetic variance in fitness?

Standard models in population genetics look up at the evolution of few loci which impact fitness. The variance in fitness is determined by the genetic variance and the environmental variance (and the ...
4
votes
0answers
59 views

Counterintuitive action of Vitamin D?

Vitamin D acts in a way which to me is counterintuitive. It functionally supplemets Parathormone. It in the intestinal tract steps up calcium absorption by altering nuclear gene expression and also ...
4
votes
0answers
56 views

Dogs bark at familiar person in Santa costume. Why? Don't dogs trust smell over vision?

Last night 10 humans and 2 dogs spent Christmas together. At some point, one human dissappears for a few minutes and comes back wearing a full Santa outfit. Upon respawning, the dogs start barking ...
4
votes
0answers
146 views

Statistical Coupling Analysis (SCA) to identify coevolved residues: use of ICA

We've begun to try out the SCA Matlab toolbox (latest version) downloaded from Dr. Rama Ranganathan's website, and, following the included tutorials, would like to apply it to our protein family. The ...
4
votes
0answers
43 views

Reformulation of Hamiton's rule

Who (and in which article) was the first to reformulate Hamilton's rule using the letters $B$ and $C$?. See below comments on this reformulation. Hamilton, in his 1964's article gave a mathematical ...
4
votes
0answers
125 views

Genetic expression in interspecific hybrids

Referring to interspecific hybrids, I have the following two questions:- Quoting from wikipedia:- The offspring of an interspecific cross are very often sterile; thus, hybrid sterility ...
4
votes
0answers
45 views

Does DHA increase the effects of clarithromycin?

I've read on this publication that every drug that induces CYP3A can reduce the effectiveness of clarithromycin. Clarithromycin inhibits CYP3A. But it does not say anything about the opposite ...
4
votes
0answers
29 views

Are there any online resources one can use to access raw clinical trial data without having to contact those involved in the study?

I want to do some statistical analysis and I have a preference for real data so I was wondering if there's somewhere I can get such data for free without a heap of bother in phoning other those ...
4
votes
0answers
179 views

How to reduce/eliminate cell clumping in suspension CHO cells, without using an anti clumping agent?

what is the best way to eliminate clumping suspension cells used for transfection. Anti clumping agents interfere transfection and hence can't be used. Though maintaining the cell density low helps, ...
4
votes
0answers
50 views

How significant is RNA degradation with removal of cap/polyA's in eukaryotes, or UTR's in prokaryotes?

Question is rather self-explanatory, but segmented into two parts. I'm attempting to make use of a repression system that employs cleaving RNA at specific areas with ribozymes with the intent of ...
4
votes
0answers
74 views

Model for fluctuating selection

Is there any mathematical model to predict the behaviour and long-term consequence of counter-acting selection at different time scale? For example, let's consider the bi-allelic gene $A$, with ...
4
votes
0answers
31 views

How to search for organisms by criteria such as growth substrate and overflow metabolites?

I'm looking for a database or a systematic way to search for organisms which meet certain criteria. My criteria descending importance are: growth substrate chemolithoautotrophy (on which substrate) ...
4
votes
0answers
42 views

Honeybee decision process: new food, new home, new threat

I have heard that honeybees send out scouts, then based on the scout reports more bees go then come back and report and so they are supposed to be efficient decision makers. Can you give as complete ...
4
votes
0answers
48 views

Does preservation in ethanol alter leaf litter mass?

I have benthic samples that were collected with an Ekman dredge from some small ponds. The samples contain quite a bit of coarse particulate organic matter (CPOM, basically dead leaves). I would ...
4
votes
0answers
72 views

What controls leaf senescence in deciduous tree species, and how can I predict it?

If I want to predict litterfall, what data do I need to collect, and what statistical model might I use? For example, I might use the following coding to record phenological stage every other day, or ...
4
votes
0answers
84 views

Do mammals develop tolerance to anticholinergics?

I know that first generation H1 antagonists, commonly known as antihistamines have anticholinergic effects. Their sedative side effects go away due to tolerance, but as for their anticholinergic side ...
4
votes
0answers
164 views

How do the pharmacodynamics of the NSAIDs differ and are there “resistant” COX phenotypes?

I know that the non-steroidal anti-inflammatory drugs (e.g., aspirin, ibuprofen, naproxen) affect the enzymes cyclooxygenase (types I and II). Is there any difference in the degree to which these ...
4
votes
0answers
51 views

Does a mydriatic drug neutralize the action of a miotic?

If a person were administered a mydriatic, would the subsequent application of a miotic neutralize the action of the former? If the sequence were reversed would a mydriatic neutralize the effect of a ...
4
votes
0answers
65 views

effect of background selection on promoter regions compared to distant enhancers?

Has anyone looked at the effect of background selection on the levels of conservation of promoter regions compared to distant enhancers? Do promoter regions have a higher conservation due to ...
4
votes
0answers
47 views

Do you know of any disease where HLA / MHC association discovery has led to better treatment or management?

If we discover an association between a disease and a particular HLA type (MHC class I or class II molecule) then it may provide us with some insight into the disease in a very basic way. However, ...
4
votes
0answers
36 views

harvesting fertilized eggs from Tetraodontidae species?

I would like to know how easy/difficult it is to harvest fertilized eggs from Tetraodontidae species such as Tetraodon nigroviridis or Takigufu rubripes compared to zebrafish? Ultimately, I would like ...
4
votes
0answers
93 views

Dimensionless number for blood volume

Comments from the question How is the blood volume of a living organism measured without killing it? by @Nico discussed that the time of blood recirculation scales with the size of the organism. I was ...
4
votes
0answers
73 views

What is the distance between the 3' 18s rRNA (the Kozak consensus sequence) and the A-site of eukaryotic ribosomes during protein translation?

Reposted from Quora http://www.quora.com/What-is-the-distance-between-the-3-18s-rRNA-the-Kozak-consensus-sequence-and-the-A-site-of-eukaryotic-ribosomes-during-protein-translation The Kozak sequence ...

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