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1.
N. Rashevsky 《Bulletin of mathematical biology》1971,33(4):555-559
In combining the author's theories of organismic sets (Rashevsky,Bull. Math. Biophysics,31, 159–198, 1969a) and Robert Rosen's theory of (M, R)-systems (Bull. Math. Biophysics,20, 245–265, 1958), a conclusion is reached that the number of either normal or pathological phenomena in organismic sets may
occur. Those phenomena are characterized by occurring spontaneously once in a while but are not exactly periodic. Some epilepsies
are an example of such pathological phenomena in the brain. 相似文献
2.
N. Rashevsky 《Bulletin of mathematical biology》1966,28(4):655-661
The paper develops further some suggestions made previously (Bulletin of Mathematical Biophysics,28, 283–308, 1966) that certain biological phenomena may be more easily interpreted from a “sociological” point of view by considering
the organism as a social aggregate of cells and a cell as a social aggregate of genes. In this light the problems of origin
of life on earth, of aging, and of parasitism and symbiosis are discussed. The notion of social aggregates of different orders
is introduced. 相似文献
3.
N. Rashevsky 《Bulletin of mathematical biology》1964,26(1):57-61
In connection with a series of previous papers by this author (Bulletin of Mathematical Biophysics,21, 299–308, 375–385;22, 257–262, 263–267;23, 19–29;24, 319–325) results obtained by A. Crawford (Economics
5, 417–428) on the effects of irrelevant lights on reaction times toward a given light stimulus are discussed. The conclusions
from a previous paper of this author (Bulletin of Mathematical Biophysics,23, 19–29) are elaborated. 相似文献
4.
Michael Abib 《Bulletin of mathematical biology》1966,28(4):511-517
We show that when we represent (ℓ, ℛ)-systems with fixed genome as automata (sequential machines), we get automata with output-dependent
states. This yields a short proof that ((ℓ, ℛ)-systems from a subcategory of automata—and with more homomorphisms than previously
exhibited. We show how ((ℓ, ℛ)-systems with variable genetic structure may be represented as automata and use this embedding
to set up a larger subcategory of the category of automata. An analogy with dynamical systems is briefly discussed. This paper
presents a formal exploration and extension of some of the ideas presented by Rosen (Bull. Math. Biophyss,26, 103–111, 1964;28, 141–148;28 149–151). We refer the reader to these papers, and references cited therein, for a discussion of the relevance of this material
to relational biology. 相似文献
5.
I. Băianu 《Bulletin of mathematical biology》1970,32(4):539-561
The representation of biological systems in terms of organismic supercategories, introduced in previous papers (Bull. Math. Biophysics,30, 625–636;31, 59–70) is further discussed. To state more clearly this representation some new definitions are introduced. Also, some necessary
changes in axiomatics are made. The conclusion is reached that any organismic supercategory has at least one superpushout,
and this expresses the fact that biological systems are multistable. This way a connection between some results of Rashevsky’s
theory of organismic sets and our results becomes obvious. 相似文献
6.
N. Rashevsky 《Bulletin of mathematical biology》1969,31(3):605-617
A previous study (Bull. Math. Biophysics,31, 417–427, 1969) on the definitions of stability of equilibria in organismic sets determined byQ relations is continued. An attempt is made to bring this definition into a form as similar as possible to that used in physical
systems determined byF-relations. With examples taken from physics, biology and sociology, it is shown that a definition of equilibria forQ-relational systems similar to the definitions used in physics can be obtained, provided the concept of stable or unstable
structures of a system determined byQ-relations is considered in a probabilistic manner. This offers an illustration of “fuzzy categories,” a notion introduced
by I. Bąianu and M. Marinescu (Bull. Math. Biophysics,30, 625–635, 1968), in their paper on organismic supercategories, which is designed to provide a mathematical formalism for
Rashevsky's theory of Organismic Sets (Bull. Math. Biophysics,29, 389–393, 1967;30, 163–174, 1968;31, 159–198, 1969). A suggestion is made for a method of mapping the abstract discrete space ofQ-relations on a continuum of variables ofF-relations. Problems of polymorphism and metamorphosis, both in biological and social organisms, are discussed in the light
of the theory. 相似文献
7.
H. E. Hart 《Bulletin of mathematical biology》1960,22(1):41-52
The methods of C. W. Sheppard and A. S. Householder (Jour. App. Physcis,22, 510–20, 1951), H. D. Landahl (Bull. Math. Biophysics,16, 151–54, 1954) and H. E. Hart (Bull. Math. Biophysics,17, 87–94, 1955;ibid.,19, 61–72, 1957;ibid.,20, 281–87, 1958) are employed in studying the kinetics of generalN compartment systems. It is shown that the nature of the transfer processes occurring in fluid flow systems and the chemical
processes occurring in quadratic systems and in catalyzed quadratic systems can in principle be completely determined for
all polynomial dependencies. Systems involving three-body and higher-order interactions can be completely solved, however,
only if supplementary information is available.
Research supported by the Atomic Energy Commission, Contract AT (30-1)-1551. 相似文献
8.
Fresh and dry body weights (FW, DW) were greater for adult southern green stink bug,Nezara viridula (L.) than for the brown stink bug,Euschistus heros F. throughout the year in southern Brazil. FemalesN. viridula significantly increased FW and DW in late summer-early autumn, and during mid-spring; femaleE. heros did not show the same rates of increase in FW and DW. FemaleN. viridula were heavier than males, particularly during summer; however, female and maleE. heros were generally similar in weight.E. heros contained significantly greater amounts of lipid thanN. viridula, during mid-autumn to early-spring (April–September). Survivorship (%) and total longevity ofE. heros adults provided water only was greater (34.6–24.6 days, for females and males) than that forN. viridula (14.8–13.0 days); without water and food, longevity was drastically reduced (<7 days) for both species. 相似文献
9.
The theory of relations between sets, proposed and outlined in previous publications (Bull. Math. Biophysics,23, 233–235, 1961;28, 117–124, 1966;28, 309–313, 1966), is tentatively expanded and generalized with a view to biological applications. 相似文献
10.
I. Băianu 《Bulletin of mathematical biology》1971,33(3):339-354
The representation of biological systems by means of organismic supercategories, developed in previous papers (Bull. Math. Biophysics,30, 625–636;31, 59–71;32, 539–561), is further discussed. The different approaches to relational biology, developed by Rashevsky, Rosen and by Băianu
and Marinescu, are compared with Qualitative Dynamics of Systems which was initiated by Henri Poincaré (1881). On the basis
of this comparison some concrete result concerning dynamics of genetic system, development, fertilization, regeneration, analogies,
and oncogenesis are derived. 相似文献
11.
Ernesto Trucco 《Bulletin of mathematical biology》1957,19(1):19-21
In the bio-topological transformation between graphs denoted by (T
(1)
X) N. Rashevsky (Bull. Math. Biophysics,18, 173–88, 1956) considers the number of fundamental sets which (a) have only one specialized point as source (and no other
sources), (b) have no points in common (are “disjoined”); he proves that this number is an invariant of the transformation.
In this note we show that Rashevsky's Theorem can be extended as follows:The number of fundamental sets of the first category is an invariant of the transformation. We must, however, count the subsidiary points of the transformed graph as specialized points. We recall that fundamental
sets of the first category are those whose sources consist of specialized points only (Trucco,Bull. Math. Biophysics,18, 65–85, 1956). But in this modified version of the Theorem the fundamental sets may have more than one source and need not
be disjoined. 相似文献
12.
N. Rashevsky 《Bulletin of mathematical biology》1972,34(2):213-222
This paper compares two previously published neural models for epilepsies (Bull. Math. Biophysics,33, 539–553, 1971;34, 71–78, 1972). The second model is developed in more detail and an attempt is made to bring it more in line with established
neurological findings. The question of classification of some epilepsies is briefly discussed. 相似文献
13.
N. Rashevsky 《Bulletin of mathematical biology》1963,25(1):59-74
The principle of adequate design (N. Rashevsky,Mathematical Biophysics, 3rd Ed., Vol. II, Dover Publications, Inc., New York, 1960) is applied to some parts of the cardiovascular system, extending
the work of David Cohn (Bull. Math. Biophysics,16, 59–74, 1954;ibid.,17, 219–227, 1955). In addition to the diameterr
a
of the aorta and the peripheral resistanceR, calculated by Cohn, other quantities are estimated as to their order of magnitude. It is shown that the specifications of
the average metabolic rate lead, from considerations of design, to the possibility of evaluating the orders of magnitude of
the average blood pressure, the systolic and diastolic pressures, stroke volume of the heart, duration of the cardiac period
and the volume elasticity of the aorta. The calculated values are of the correct orders of magnitude. The purpose of the paper
is to illustrate how the application of the principle of adequate design can lead to the evaluation of the above parameters
from purely theoretical considerations, rather than from indirect measurements. 相似文献
14.
15.
N. Rashevsky 《Bulletin of mathematical biology》1968,30(2):355-357
It is suggested that the development of organismic sets is governed not by the maximalization of the integral survival value,
as suggested previously (Bull. Math. Biophysics,28, 283–308, 1966;29, 139–152, 1967;30, 163–174, 1968), but by maximizing the number of new relations which appear as an organismic set develops. 相似文献
16.
Robert Rosen 《Bulletin of mathematical biology》1965,27(1):11-14
The present note consists of two separate but related parts. In the first, a new graphtheoretic proof is presented that an
(ℳ,R)-system must always contain a nonreestablishable component. The second considers some questions concerning the relation between
re-establishability and the time-lag structure in (ℳ,R)-systems. It is supposed that the reader is familiar with the terminology of the author's previous work on (ℳ,R)-systems, particularly R. Rosen,Bull. Math. Biophysics,20, 245–260, 1958. 相似文献
17.
N. Rashevsky 《Bulletin of mathematical biology》1960,22(1):73-84
The principle of biotopological mapping (Rashevsky, 1954,Bull. Math. Biophysics,16, 317–48) is given a generalized formulation, as the principle of relational epimorphism in biology. The connection between
this principle and Robert Rosen’s representation of organisms by means of categories (1958,Bull. Math. Biophysics,20, 317–41) is studied. Rosen’s theory of (M,R)-systems, (1958,Bull. Math. Biophysics,20, 245–60) is generalized by dropping the assumption that only terminalM
i
components are sending inputs into theR
i
components. It is shown that, if the primordial organism is an (M,R)-system, then the higher organisms, obtained by a construction well discussed previously (1958,Bull. Math. Biophysics,20, 71–93), are also (M,R)-systems. Several theorems about such derived (M,R)-systems are demonstrated.
It is shown that Rosen’s concept of an organism as a set of mappings throws light on phenomena of synesthesia and also leads
to the conclusion that Gestalt phenomena must occur not only in the fields of visual and auditory perception but in perceptions
of any modality. 相似文献
18.
Due to the conventional distinction between ecological (rapid) and evolutionary (slow) timescales, ecological and population models have typically ignored the effects of evolution. Yet the potential for
rapid evolutionary change has been recently established and may be critical to understanding how populations persist in changing
environments. In this paper we examine the relationship between ecological and evolutionary dynamics, focusing on a well-studied
experimental aquatic predator-prey system (Fussmann et al., 2000, Science, 290, 1358–1360; Shertzer et al., 2002, J. Anim. Ecol., 71, 802–815; Yoshida et al., 2003, Nature, 424, 303–306). Major properties of predator-prey cycles in this system are determined by ongoing evolutionary dynamics in the
prey population. Under some conditions, however, the populations tend to apparently stable steady-state densities. These are
the subject of the present paper. We examine a previously developed model for the system, to determine how evolution shapes
properties of the equilibria, in particular the number and identity of coexisting prey genotypes. We then apply these results
to explore how evolutionary dynamics can shape the responses of the system to ‘management’: externally imposed alterations
in conditions. Specifically, we compare the behavior of the system including evolutionary dynamics, with predictions that
would be made if the potential for rapid evolutionary change is neglected. Finally, we posit some simple experiments to verify
our prediction that evolution can have significant qualitative effects on observed population-level responses to changing
conditions. 相似文献
19.
J. D. Murray 《Bulletin of mathematical biology》1990,52(1-2):117-152
The evolution of spatial pattern is a central issue in developmental biology. Turing's (Phil. Trans. R. Soc. Lond.
B237, 37–72, 1952) chemical theory of morphogenesis is a seminal contribution. In this talk I give a personal and necessarily
limited view of its impact on mathematical and developmental biology. I briefly describe some of the interesting mathematical
aspects of Turing's reaction-diffusion mechanism and discuss some of the different models which Turing's vision inspired.
The emphasis throughout is on the practical biological applications of the various theories. 相似文献
20.
Casadesus G Moreira PI Nunomura A Siedlak SL Bligh-Glover W Balraj E Petot G Smith MA Perry G 《Neurochemical research》2007,32(4-5):717-722
Metabolic alterations are a key player involved in the onset of Alzheimer disease pathophysiology and, in this review, we
focus on diet, metabolic rate, and neuronal size differences that have all been shown to play etiological and pathological
roles in Alzheimer disease. Specifically, one of the earliest manifestations of brain metabolic depression in these patients
is a sustained high caloric intake meaning that general diet is an important factor to take in account. Moreover, atrophy
in the vasculature and a reduced glucose transporter activity for the vessels is also a common feature in Alzheimer disease.
Finally, the overall size of neurons is larger in cases of Alzheimer disease than that of age-matched controls and, in individuals
with Alzheimer disease, neuronal size inversely correlates with disease duration and positively associates with oxidative
stress. Overall, clarifying cellular and molecular manifestations involved in metabolic alterations may contribute to a better
understanding of early Alzheimer disease pathophysiology.
Special issue dedicated to John P. Blass.
Gemma Casadesus and Paula I. Moreira contributed equally to this paper. Aspects of this paper were previously presented in
Neurochemical Research
28, 1549–1552, 2003 and the Journal of Alzheimer’s Disease
1, 203–206, 1999 and were used here with permission. 相似文献