Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    ISSN: 1432-0533
    Keywords: Subacute spongiform encephalopathy ; Creutzfeldt-Jakob disease ; Experimental transmission ; Small rodents ; Transmissible agent
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Further experimental transmission of Creutzfeldt-Jakob disease (CJD) from three patients to mice and rats was carried out successfully. The clinical signs and pathologic features of spongiform encephalopathy transmitted to animals were much the same as in previous experiments, except that distribution of the lesions in the mice differed with each inoculated material taken from the patients. These observations suggest the multiplicity of CJD agents, as in the case of scrapie agents.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of mathematical biology 14 (1982), S. 327-353 
    ISSN: 1432-1416
    Keywords: Evolution ; Molecular evolution ; Dynamical system ; Neo-Darwinian evolution ; Non-Darwinian evolution ; Neutral theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract In order to understand generally how the biological evolution rate depends on relevant parameters such as mutation rate, intensity of selection pressure and its persistence time, the following mathematical model is proposed: dN n (t)/dt=(m n (t-μ)N n (t)+μN n-1(t) (n=0,1,2,3...), where N n (t) and m n (t) are respectively the number and Malthusian parameter of replicons with step number n in a population at time t and μ is the mutation rate, assumed to be a positive constant. The step number of each replicon is defined as either equal to or larger by one than that of its parent, the latter case occurring when and only when mutation has taken place. The average evolution rate defined by $$\upsilon _\infty \equiv {\text{ lim}}_{t \to \infty } \sum _{n = 0}^\infty nN_n (t)/t\sum _{n = 0}^\infty N_n (t)$$ is rigorously obtained for the case (i) m n (t)=m n is independent of t (constant fitness model), where m n is essentially periodic with respect to n, and for the case (ii) $$m_n (t) = {\text{ }}s( - 1)^{n + [1/\tau ]} $$ (periodic fitness model), together with the long time average m ∞ of the average Malthusian parameter $$\bar m \equiv \sum _{n = 0}^\infty m_n (t)N_n (t)/\sum _{n = 0}^\infty N_n (t)$$ . The biological meaning of the results is discussed, comparing them with the features of actual molecular evolution and with some results of computer simulation of the model for finite populations.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of mathematical biology 11 (1981), S. 119-141 
    ISSN: 1432-1416
    Keywords: Stochastic dynamical system ; Population genetics ; Stochastic selection ; Diffusion equation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Summary A general method is given to obtain a stationary distribution in a “stochastic” one-dimensional dynamical system in which an environmental parameter specifying the dynamical system is a stationary Markov process with only two states. By applying this method, the exact stationary gene frequency distribution is obtained for a genic selection model in the environment fluctuating between two distinct states. Several limiting stationary distributions are obtained therefrom, and one of them is shown to coincide with a stationary solution of the diffusion equation heuristically derived by us for more general cases. Discussion is given on the relationship between the diffusion equations obtained by various authors starting from discrete, non-overlapping generation models.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...