Disproportion in the falling birth rate.

Since 1962 there has been a disproportionately greater fall in the number of small (less than 1000 g) live births than total live births: this has applied to Sheffield and to England and Wales but more to the former. This may have affected falling neonatal mortality rates.     

Factors associated with birth rate and live birth rate in multi-male breeding groups of rhesus monkeys

Reproductive records of 284 female rhesus monkeys housed in six multimale corrals at the California Primate Research Center were examined for the birth seasons 1977–1982 to determine possible associations between the probability of birth or live birth and female age, parity, origin, parturition in the previous season, infant birth date, and infant birth date in previous season. Multiple logistic regression analysis was used to identify and quantitate the effects of factors on the probability of birth or live birth, while controlling for the possibly confounding effects of other factors in the model. Females who had infants early in the previous season were 2.5 times as likely to give birth as those who had infants late in the previous season. Females with two or three previous births were 2.1 times as likely to give birth, and those with four or five previous births were 6.7 times as likely to give birth as were females with no or one previous birth. Controlling for other factors (age, parity, and timing of birth in the previous season), corralborn females were 3.3 times as likely to give birth as either wild-caught or domestic-born monkeys not native to the corrals. Domestic-born females who were not corral natives were 0.3 times as likely to have live births as wild-caught females. Births late in the season were 1.8 times as likely to result in live infants as births early in the season.     

Density-dependent birth rate, birth pulses and their population dynamic consequences

 In most models of population dynamics, increases in population due to birth are assumed to be time-independent, but many species reproduce only during a single period of the year. We propose a single-species model with stage structure for the dynamics in a wild animal population for which births occur in a single pulse once per time period. Using the discrete dynamical system determined by the stroboscopic map, we obtain an exact periodic solution of systems which are with Ricker functions or Beverton-Holt functions, and obtain the threshold conditions for their stability. Above this threshold, there is a characteristic sequence of bifurcations, leading to chaotic dynamics, which implies that the dynamical behaviors of the single species model with birth pulses are very complex, including small-amplitude annual oscillations, large-amplitude multi-annual cycles, and chaos. This suggests that birth pulse, in effect, provides a natural period or cyclicity that allows for a period-doubling route to chaos. Received: 13 June 2001 / Revised version: 7 September 2001 / Published online: 8 February 2002     

两性具有不同出生率和死亡率的种群动态

以往的种群动力学模型均隐含假设性比为1：1,而实际上并非总如此,不同性别的出生和死亡是不完全相同的。文中就考虑了两性具有不同出生率和死亡率的种群动态问题。可以知道种群动态只是受雌性控制,与雄性无关。     

Ethnicity in the USSR and the CIS

After the USSR: Ethnicity, Nationalism, and Politics in the Commonwealth of Independent States. Anatoly M. Khazanov. Madison: University of Wisconsin Press, 1995. 311pp.
Who Gets the Past? Competition for Ancestors among Non-Russian Intellectuals in Russia. Victor A. Shnirelman. Washington, DC: Woodrow Wilson Center Press; Baltimore, MD: Johns Hopkins University Press, 1966. 98 pp.
In the Soviet House of Culture:. Century of Perestroikas. Bruce Grant. Princeton, NJ: Princeton University Press, 1995. 225 pp.     

Biological ageing with birth rate controlled by mutations in the Penna model

Summary Within the Penna model, we assume a modification with a reproduction rate B that depends on the health state of the individual defined by the number of bad mutations. The idea is that biologically weaker individuals has got less chance to produce offsprings. The results obtained from simulations and for typical set of model parameters show that then the mortality rate q(a) is increasing faster with age a. The maximum age is also limited from about 50 percent of the biological maximum life-span for the standard Penna model, to about 40 percent. We also conclude that bad mutation distribution r(a) is altered so that younger individuals may accommodate significantly more bad mutations, up to 25 percent, as compared with the standard model (5 percent). In summary, it makes sense to force less productivity for older and weaker individuals.     

Psychosocial effects of disaster: birth rate in Aberfan.

An increased birth rate occurred in Aberfan during the five years after the disaster there in 1966. It was not confined to the bereaved parents.     

Scientific and clinical biofeedback in the USSR

This paper describes the history of biofeedback research and application in the USSR. The approach of USSR scientists to the study of basic mechanisms of biofeedback and the status of clinical applications of biofeedback in the Soviet Union are described. Trends in the publication of biofeedback-related papers in Russian are presented, and the present "state of the art" described. Promising prospects for biofeedback research and application are discussed.