59
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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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37
votes
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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25
votes
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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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22
votes
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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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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11
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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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8
votes
Empirical evidence for Group Selection?
Let's start with your definition.
"Selection for traits that would be beneficial to a population of units at the expense of an individual unit possessing the trait"
This is not a good definition of ...
8
votes
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Population dynamics ODE with Allee Effects
First, Allee effects (also positive density dependence) can be modelled in several different ways, and the equation you give is one example. The terms weak and strong Allee effects are in my ...
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8
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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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8
votes
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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7
votes
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Can/Have cancer cells be/been used in stem cell culture lines?
Cancer cells can be and are used in cell culture. HeLa cells were the first human cell line to be grown in culture and they were derived from a cervical tumor.
That being said, Cancer cell lines ...
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7
votes
Exponential growth equation and bacteria
Considering your assumption:
I'm just looking at the exponential part, where the simple exponential
equation works. If we assume there's sufficient nutrients for bacteria
to grow unchecked for ...
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7
votes
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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:
$$t \sim \text{e}^{-\lambda t} \implies \langle t \rangle = \int_0^\infty t \ \text{e}^{-\lambda t} \; \text{...
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Can/Have cancer cells be/been used in stem cell culture lines?
Adding onto AMR's answer, cancer cell lines are used extensively for research. They are typically fast to grow. HeLa Long grow to capacity of a 10cm dish within about 48hours, depending how you split ...
- 509
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votes
Do the claims in this paper have any degree of validity?
I'm afraid I laughed a bit when reading that paper for the first time.
Why? Well, here's what they essentially did: They tried to model evolution by implementing an algorithm. They had a population ...
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The title et al
The Latin phrase et alia (abbreviated et al.) means and others.
It is not limited to biologists, nor those of different nationalities. If I refer to this computer graphics article, I can refer to it ...
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Why is the null hypothesis of trait evolution Brownian motion?
I think that the simple answer to this question is that the present comparative methodology was largely established by Felsenstein 1985, American Naturalist. For mathematical convenience, he suggested ...
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6
votes
What does it mean to quantitatively describe a cell?
Quantitative in the context of biology is similar to chemistry, and means "how much of something there is" - for example, how much of a particular protein is produced under what conditions.
...
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5
votes
Stochastic parameters in population growth equations
Since you are asking for the biological interpretations about these parameters, it is important to realize that the model you are presenting is a non-dimensionalized version of this model:
$$ \frac{...
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5
votes
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Are there any theories using thermodynamics/statistical mechanics or information theory principles to modelling in ecology?
John Harte's work on applying the mathematical theory of maximum entropy to ecology is certainly one of the better known examples of the application of this area of mathematics to science, in part ...
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What are we missing about the real workings of the evolutionary process?
The question appears interesting and made me think but I might not fully understand it. Let me know if I am answering your question.
Genetic algorithm vs simulation of evolutionary processes
I think ...
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5
votes
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How can I obtain a computer readable model of Dr. Gerhard Michal's biological pathways map?
Roche's Biochemical Pathways works as a big png image and just put labels on the map. But you could try to extract data using queries like http://biochemical-pathways.com/pol/fts/query?query=Glutarate
...
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votes
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Is "A" inhibiting "B" and vice-versa, a positive feedback loop?
The situation that you presented in which an entity A inhibits the production of another entity B which in turn inhibits A, is a positive feedback.
In a network path or a loop the overall sign of the ...
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5
votes
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Biological meaning of Lotka-Volterra Jacobian matrices
The Jacobian tells how the system changes along different state variables (which can be, for instance, the concentrations of the predator and the prey).
The Jacobian matrix by itself doesn't give you ...
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5
votes
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 ...
5
votes
Accepted
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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