# Tag Info

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### Are the social-distancing measures implemented against SARS-CoV-2 also suppressing the spread of other viruses?

Yes, this helps as well with other infectious diseases. A good example is the flu, which season was measurably shorter this year than in other years on record. See the figure from the reference 1 for ...
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### Are the social-distancing measures implemented against SARS-CoV-2 also suppressing the spread of other viruses?

In addition to Chris' answer above, the effect is even more pronounced in Southern Hemisphere countries where flu season started during the pandemic. The New Zealand lockdown and health response ...
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### Why don't viruses reach broad concentration outdoors in a city like allergens?

2, 4, 5, and 6. 6 being that the UV light (from the sun), fluctuations in temperature, humidity, wind etc mean that the virions are decayed relatively rapidly for most virus species. To address (1): ...
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### Is there a bacterium that became a virus?

This virology site has a post about a 2017 paper about membrane-vesicled plasmids that act in ways that are theorized to be precursors to how viruses work: It is likely that the plasmid-containing ...
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### Why don't viruses reach broad concentration outdoors in a city like allergens?

In another answer elsewhere on StackExchange, a poster estimated that there might be something like 100 g to 1 kg of SARS-CoV-2 virus worldwide, and that's an estimate of all the virus, including what ...
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### How do you calculate the time until the steady-state of a drug?

Here's a short simulation that show the process. You can find more about how to simulate a half decay process here You can notice that the first dose of 40 mg should decay to 20 mg in 30 hours, but ...
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### Examples of Differential equations in Biology

For biochemistry students the obvious link to differential equations is the Michaelis–Menten equation which is a simple model of the kinetics of reactions involving enzymes. Your students will be ...
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### Is there a bacterium that became a virus?

There are giant viruses that some people think could be degenerate bacteria. https://en.wikipedia.org/wiki/Mimivirus Mimivirus shows many characteristics which place it at the boundary between ...
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### Examples of Differential equations in Biology

Update please follow Charles E. Grant's advice and do Michaelis-Menten! Hodgkin-Huxley as suggested by commenter ctwardy is a great idea too. Original answer I would strongly recommend the book ...
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### How do you calculate the time until the steady-state of a drug?

heracho's answer does a good job showing the realistic timing. However you can do a pretty good approximation with a simple differential equation, where you approximate the daily dose as a continuous ...
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### Can we use differential equations for population that is discrete?

You can make the continuous approximation when the population size is large. As mentioned by arboviral, there are algorithms that allow you to perform stochastic simulations with discrete variables. ...
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### How do you calculate the time until the steady-state of a drug?

Let's take a moment to think about what it means for a drug dosed multiple times to reach "steady-state": "steady-state" would mean that it doesn't matter much if you've been ...
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### Isn't sexy son hypothesis circular?

The process is self-reinforcing but the argument is not circular (no tautology implied). As soon as some male traits are considered more sexy than others, then there is selection for females to like ...
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### Understanding expected mean number of breeding seasons

It's just a continuous version of the discrete calculation. The discrete version is the (infinite series) sum $$\sum_{i = 0}^\infty S^i \cdot bp$$ adding up every (chance of survival to season $i$) ...
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### Understanding expected mean number of breeding seasons

I think your explanation is correct. The expected value of the exponential distribution is: t \sim \text{e}^{-\lambda t} \implies \langle t \rangle = \int_0^\infty t \ \text{e}^{-\lambda t} \; \text{...
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### The title et al

The Latin phrase et alia (abbreviated et al.) means and others. It is not limited to biologists, nor those of different nationalities. If I refer to this computer graphics article, I can refer to it ...
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### Why is the null hypothesis of trait evolution Brownian motion?

I think that the simple answer to this question is that the present comparative methodology was largely established by Felsenstein 1985, American Naturalist. For mathematical convenience, he suggested ...
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### What does it mean to quantitatively describe a cell?

Quantitative in the context of biology is similar to chemistry, and means "how much of something there is" - for example, how much of a particular protein is produced under what conditions. ...
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### Examples of Differential equations in Biology

Are Twelve ODEs for mitochondrial membrane potential (ΔΨm), and matrix concentrations of Ca2+, NADH, ADP, and TCA cycle intermediates, used to model the response of mitochondria to changes in ...
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### Can we use differential equations for population that is discrete?

I'd hardly call myself an expert on this topic by any stretch of the imagination, but you can actually come up with good approximations based on ODE-based models by rounding off to the nearest whole ...
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### Mathematical model about the relationship between two animal species

The model you present here is a special case of the Lotka-Volterra competition equations, where the two species have the same effect on each other (i.e., symmetric competition). Some things to think ...
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### Are resonances the reason receptors work?

Photoreceptors themselves dont act as oscilators, a single receptor is either 'on' or 'off' - it does not respond differently to different wavelenghts. Humans have Trichromatic vision, which means ...
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### A cure for radiation exposure?

Would that be a good thing? Recent research from the Samson lab at MIT suggests that there are side effects from amplifying the DNA repair mechanism. Hyperactivity of a base-excision repair (BER) ...
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### Remarkable attempts of studying biological systems axiomatically

It's hard for me to know the degree to which the Kaczynski quote is wrapped up in what you are interested in, so I will answer your question very narrowly without considering that quote: does there ...
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### What could be a refuge in host-parasitoid models

The most typical situation is a size refuge, i.e. prey/hosts that are too large or too small to attack (or possibly too small to be useful) are not attacked, or are attacked less, than hosts that are ...
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### Can we use differential equations for population that is discrete?

Yes, you can. For example, the Gillespie algorithm (Gillespie-Doob algorithm) generates a statistically correct trajectory of a discrete population from a system of differential equations. This is ...
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