population Definition and 262 Threads

Homework Statement "The very simple population model for a resource limited population with constant immigration, and no breeding, M'(t) = M(S-M) + I attempts to describe the growth of corals on a reef. Function M(t) represents the biomass of corals." a - Explain which term gives the...

I heard that the avian flu could kill more than 3,000,000,000 human beings. Is this really possible?

I am trying to model the growth of a population which replicates at a rate of 160% every four hours. Also 50 000 members die every hour. so t denoting time in hours, P denoting the population, k being 0.4 I wrote: dP/dt=kp-50 000 *t Is my approach to solving the differential faulty...

Homework Statement A 95% CI for the population proportion of professional tennis players who earn more than $2 millions a year is found to be [0.82, 0.88]. Given this information the sample size that was used was approximately A) 545 B) 382 C) 233 D) 378 Answer: A) 545 Homework...

I did some research in regards to the age and metallicity of population I stars in hopes to come up with a novel solution to the Fermi Paradox. Anyways, while the metallicity of the oldest Population I stars can be tracked down to be something like -1 (10% of that of the sun) determining the age...

i guess I am trying to find the relationship between population growth and time. bacteria population is 1000 during time 0minutes. bacteria p.: 2000 time: 30 minutes bacteria p.: 4000 time: 60 minutes bacteria p.: 8000 time: 90 minutes bacteria p.:16000 time: 120 minutes...

This is a bit of a general question, but does anyone happen to know a good book, resource, or author in the field of accurate population growth and decline modeling? I'd like to find a good academic (non-website) source to get a general idea of the main things a population ecologist looks at...

Have population II stars been observed or speculated to have planets?

How many people are living in India? With the help of following data can you find How many people were listed as living in India and give logic also ? . The population of some countries is calculated based upon some logic and listed here ( It has no link with the facts) :- . USA...

Homework Statement Hey all I've got a problem to do with population density. It asks for you to show the number of people living between arbitrary points a and b from the centre of the town is equal to: P(a,b)=2\pi\int^{b}_{a}rf(r)dr Where f(r) is the population density. Note that a...

Not sure if this is the right place to post homework questions or not, but my math problem is this: A consumer magazine has contacted a simple random sample of 33 owners of a certain model of automobile and asked each owner how many defects had to be corrected within the first 2 months of...

Homework Statement Dolor and her cousin Largo have conceived a child. They are very concerned about the baby, because they have heard that children of close relatives have a higher incidence of birth defects and/or inherited recessive disorders. They know that their maternal grandmother was a...

The number of bacteria in a lab is model by the function M that satisfies the logistic differential equation dM/dt = 0.6M (1 - (M/200) ), where t is the time in days and M(0) = 50. What is the limit of M(t) as t approach infinity? Do i use the fundamental theorem of calculus?

Use P0 = 3.9 (1790 population) as your initial condition to find the particular solution for this differential equation. Note: You may find it easier to solve in terms of the constants a and b. Show all the steps in your solution. This is the last step to a multi-part problem. I basically did...

Homework Statement Biologists stocked a lake with `400` fish and estimated the carrying capacity (the maximal population for the fish of that species in that lake) to be `6900`. The number of fish doubled in the first year. Homework Equations The Attempt at a Solution I know...

"Aftermath: Population Zero" view of unattended nuke plants The National Geographic TV special called "Aftermath: Population Zero" explored the consequences if everyone on Earth vanished, particularly from the standpoint of suddenly unattended technical and industrial systems, and especially...

Use P0 = 3.9 (1790 population) as your initial condition to find the particular solution for this differential equation. Note: You may find it easier to solve in terms of the constants a and b. Show all the steps in your solution. This is the last step to a multi-part problem. I basically...

Hi everyone, From this website (link: http://hyperphysics.phy-astr.gsu.edu/HBASE/solids/fermi3.html#c1 ), we get the following expression: Population Density of Conduction Electron = \int ^{\infty}_{Egap}N(E)d(E) = \frac{2^{5/2}(m \pi k T)^{3/2} exp (-E gap/2kT)}{h^3} My questions are based...

Which country has the potential to have the highest GDP per head of population if its economy was run perfectly? Can one country run a perfect economy if its trading partners do not? Is there a country that can get by on its own with internal markets?

Hi, I'm writing to you as a graduate applied math student who has taken a recent interest in biology and the modeling of all kinds of microbiological systems, something I plan on continuing with in my PhD. As such, I'm modeling biology without knowing as much about it as I should :P My...

Homework Statement In summer months, female aphids reproduce by parthenogenesis, giving birth to females from unfertilized eggs. These females mature within 24h and begin reproducing in the same way. Assume that each female aphid produced two females the day after she herself is born, and and...

Homework Statement Dissolved O2 Content. Industrial wastes and sewage dumped into our rivers and streams absorb oxygen and thereby reduce the amount of dissolved oxygen available for fish and other forms of aquatic life. One state agency requires a minimum of 5 parts per million (ppm) of...

Malthus' principle of population growth can be written as the differential equation y'=ky where y(t) is the population t years after the initial measurement and k is the growth constant. The solution to this differential equation is given by y(t)=Ae^{kt} where A is the initial...

Can anyone tell me how to calculate population growth. my book doesn't tell me how to do that. is the formula rN=dN/dt

Consider a reactor being held sub-critical, Keff < 1, by control rods. The reactor has heavy water reflector and has been operatored for some time prior to the current state (we got Photo Neutrons). Keff is then bought to 1. It seems to me, for Keff = 1 the neutron population should be...

A population has two alleles, B and b. the allele frequency of B is 0.73. what is the heterozygotes frequency, if the population is in H-W equilibrium?

The Problem: Consider a species in which no individuals live beyond 3 years. Divide the population into four age groups labelled by n = 0,1,2 and 3. Assume that only the second and third groups can reproduce. For each group n let bn denote the birthrate and d_n the death rate. Find a matrix A...

Here is the full question: Reducing human population, disregarding the difficulty, would be the most effective way to: - reduce pollution (air, water, soil, noise...) and - avoid depleting natural resources (fish stocks, oil, forests...) and - prevent extinction of living species, as well as -...

I watched 60 minutes today and they used a new example of global warming in action! The journalist was talking to two arctic biologists, and the man said that there has been a 50% reduction in penguin population. That sure sounds like a big number! Is that true? I don't believe a mention of the...

Homework Statement Vancouver Island has an area of 33000km^2 but no wombats. If we release a pair of wombats on Vancouver Island and their annual rate of increase is 50%, how many years will it be before the wombat population reaches one pair per km^2? Homework Equations [A]t=[A]oe^-kt...

i was just wondering abt this thing for a while... the total no. of human beings are increasing over the decades...which means some %ge of the Earth's matter is getting converted in the form of humans...suppose if the population goes on increasing, then theoretically there should be only humans...

Hello, i am having trouble with working out what the population mean is. Is there a formula in Microsoft Excel to workout the population mean. I have a population of 200

Hey folks, I'm currently at grad school and am working on an algorithm to try and model the rate of supernova (type I and II) in our galaxy. I really need to know the following information. 1) Where can I find information on HOW MANY of the different types of stars there are in our...

The initial mass of a species of fish in a lake is 7 million tonnes. The mass of fish, if left alone, would increase at a rate proportional to the mass, with a proportionality constant of 2/year. However, commercial fishing removes fish mass at a constant rate of 15 million tonnes per year...

Homework Statement Suppose that when a certain lake is stocked with a population P of fish, the birth and death rates \alpha and \beta are inversely proportional to \sqrt{P} , so that \frac{dP}{dt} = k \sqrt{p} Find P(t) if P(0)=C The Attempt at a Solution \frac{dP}{\sqrt{p}} = k dt...

i was just reading about chinas 1.4 boy to girl birth ratio and it has me wondering is this going on in the united states? it seems to me like finding the right girls has always been a fight. shotgun wedding :eek: i hope not.

Homework Statement Harley-Davidson motorcyles make up 14% of all the motorcyles registered in the United States. You plan to interview an SRS of 500 motorcyle owners. a) what the approximate distribution of the proportion of your sample who owns harleys? b) Is your sample likely to contain...

Hi, I was wondering if anyone out here on a Friday night could help me understand population modeling. Here is what I have as a problem (this is pretty simple because my goal here is to understand the thinking behind the madness :rolleyes: ) - The population of a certain community is...

I was discussing Plato's Republic in class and we got into eugenics. Anyway, I remember hearing somewhere that IQ always deviates towards the population mean, and, therefore, it is not true that eugenics will result in benefits for the population (at least when done on the basis of IQ). Is this...

I'm stuck on what to do here. The question reads Consider a population P(t) satisfying the logistic equation dP/dt = aP-bP^2, where B = aP is the time rate at which births occur and D = bP^2 is the rate at which deaths occer. If the intial population is P(0) = P_0 (supposed to be P sub not)...

Two species x, y compete for the same limited food supply according to the model x'=3x-2x^2-2xy y'=4y-3y^2-2xy Find and classify the equilibrium points. Please please can anyone help me with this??

Is the identification of a GRB with a 'hyper-nova' at z = 6.295 when the universe was 900 Myrs old (standard model) the first detection of the long awaited Population III stars that caused the 'first light'?Ancient blast comes to light That article speaks of a mass of 20MSolar, but I don't...

I am having a problem with finding the constant K in This problem. The time rate of change of an alligator population P in a swamp is proportional to the square root of P. The swamp contains 9 alligators in 2000 and 25 alligators in 2005. When will there be 44 alligators in the swamp? I...

I am quite sure the first approach is to use partial fractions but I am unclear how to finish this equation 1/P*dP/dt=b+aP

http://www.nytimes.com/2006/01/13/national/13baby.html?ei=5090&en=7986dfa5eaaf53ed&ex=1294808400&partner=rssuserland&emc=rss&pagewanted=all If any of you want to have that baby, you better hurry the heck up.

Suppose that in any given year, the population of a certain endangered species is reduced by 25%. If the population is now 7500, in how many years will the population be 4000? Well, I know that the formula for this is P(t) = Cekt. I just can't figure out the value of k. i did 7500 x .25 =...

http://www.gamespot.com/news/6141517.html Is it just me or is that a lot of people playing one game. Whats so special about World of Warcraft anyway? Any hardcore WoW players on PF.

In the October edition of the magazine, Active Trader, a reader writing in Chat Room, "Deviating from deviation?" asks that in explaining last month the viaiance, why did you not in your example divide by two? {(8-9)^2 + (9-9)^2 +(10-9)^2}/3 = .667. The explanation given is nothing more...

The Earth's current Human population is 6 Billion. Some time in 1940 the world population was 3 billion and around 1750 the population was about 500 million. Is there a scientific method to extrapolate the Human population for the date 5000 b.c? Thanks.

Hello I am having major difficulties with two Differential equation. 1. If I have the equation P=2000/(1+9e^.06t). where p=population and t=time. How do I work out when the population is growing the fastest? To work this question out do I just make t the subject and diff twice and let it...