Micrococci in the skin microbiocenosis of the breasts. Ecologic characteristics of the colony

The ecological characteristics of the micrococcal community on the skin of the mammary glands of nulligravidae, pregnant and puerperant women have been studied. The species composition of the community, the population size and occurrence of each species, its participation in the dominant structure of the community have been determined. The comparative evaluation of its types has been made. A decrease in the dominating role of M. luteus in pregnant and puerperant women has been established. The tendency towards the normalization of the structure of the community in the postnatal period has been established.     

The ecology of the introduced patas monkey (Erythrocebus patas) population of Southwestern Puerto Rico

This paper presents the results of a study on the introduced, free-ranging patas monkey population of Southwestern Puerto Rico (SWPR). It describes information on the population size, social group composition, diet, daily ranging patterns, and patas home range during a 3 year period. The patas monkey population in the study area consisted of approximately 120 individuals in four heterosexual groups and several all-male bands. Within their home ranges (26.8 km²), the population density was 4.47 individuals/km². Home range size among the population's four heterosexual groups varied from 3.72 km² to 15.39 km², and minimum daily distance traveled ranged from 0.8–2.0 km. In general, the social structure and mating system of this population parallels what has been described for African populations. However, habitat use, ranging behavior, and the quality of intergroup interactions suggests that patas of this population exhibit territorial behavior. Am. J. Primatol. 45:351–365, 1998. © 1998 Wiley-Liss, Inc.     

The daily integral of photosynthesis by Planktothrix rubescens during summer stratification and autumnal mixing in Lake Zürich

It has been suggested that the populations of planktonic cyanobacteria that occupy the metalimnion of stratified lakes during the summer months may be aestivating between the main periods of growth during entrainment in the epilimnion in spring and summer. We determined the vertical distribution of the biomass and daily integral of photosynthesis of the population of Planktothrix ( Oscillatoria ) rubescens in Lake Zürich for 136 d from July to November 1995. The population showed an 80-fold increase during the stratified period but it only doubled over the subsequent period of entrainment. During the first eight days, part of the increase was attributed to recruitment of filaments floating up from greater depths but all of the subsequent production could be accounted for by photoautotrophic growth. On sunny days the biomass-specific photosynthesis of this population reached some of the highest values over the whole period despite its depth (>13 m). On very cloudy days, however, primary productivity was very low and on 4 days, when the mean depth of the population exceeded 15 m, there was no net production. Over the whole period of the study, the accumulated photosynthetic production exceeded the increase in biomass of the population by a factor of 9·5. Although much of this production occurred during the period of entrainment only a small proportion was translated into growth of the population. It is concluded that the growth that takes place in the period of stratification in the metalimnion is essential to subsequent production.     

The epidemic process as a system. The social regulators of the epidemic process

The article deals with the mechanisms of spontaneous (urbanization, the international migration of population, the anthropogenic transformation of nature) and goal-oriented regulatory action on the epidemic process. Social factors have been shown to transform into ecological ones with the subsequent transformation of information in the parasitic system and their reflection in the social subsystem as the indices of the risk of infection and its socio-economical importance. Using the processes of urbanization as an example, the present work demonstrates that the mechanism of transmission acts as a filter whose specific features are determined by a range of social factors playing the most important role in the regulation of the epidemic process on the socio-ecosystemic level of its organization.     

Reproductive conflict delays the recovery of an endangered social species

1. Evolutionary theory predicts that individuals, in order to increase their relative fitness, can evolve behaviours that are detrimental for the group or population. This mismatch is particularly visible in social organisms. Despite its potential to affect the population dynamics of social animals, this principle has not yet been applied to real-life conservation. 2. Social group structure has been argued to stabilize population dynamics due to the buffering effects of nonreproducing subordinates. However, competition for breeding positions in such species can also interfere with the reproduction of breeding pairs. 3. Seychelles magpie robins, Copsychus sechellarum, live in social groups where subordinate individuals do not breed. Analysis of long-term individual-based data and short-term behavioural observations show that subordinates increase the territorial takeover frequency of established breeders. Such takeovers delay offspring production and decrease territory productivity. 4. Individual-based simulations of the Seychelles magpie robin population parameterized with the long-term data show that this process has significantly postponed the recovery of the species from the Critically Endangered status. 5. Social conflict thus can extend the period of high extinction risk, which we show to have population consequences that should be taken into account in management programmes. This is the first quantitative assessment of the effects of social conflict on conservation.     

The phenology of leaf life spans in woodland populations of the ferns Dryopteris filix-mas (L.) Schott and D. dilatata (Hoffm.) A. Gray in Derbyshire

WILLMOT, A., 1989. The phenology of leaf life spans in woodland populations of the ferns Dryopteris filix-mas (L.) Schott and D. dilatata (Hoffm.) A. Gray in Derbyshire. The results of a survey on the number of upright fronds per plant in a population of Dryopteris filix-mas and in a population of D. dilatata over a 14 month period are presented. These coupled with similar information on the number of developing fronds per plant demonstrate that large plants in the population of each species were summergreen, while small ones were wintergreen. This size-specific difference in leaf phenology does not seem to have been recorded before in Dryopteris filix-mas. It is suggested that this difference, in both species, may have been due to either the different environments in which the plants grew or to a risk-sensitive strategy in the small plants. It is considered that such a strategy might be concerned with the obtaining or retention of resources at a critical period in the life history of the species.     

Social selection in human populations. I. Modification of the fitness of offspring by an affected parent.

The concept of social selection for deleterious genes has been introduced by considering two alleles at one locus. A social selection model is constructed by assuming that the fitness of an individual is determined by his or her own as well as the parental phenotypes. It is shown that the equilibrium gene frequency depends on the loss of fitness of an individual due to the trait (gamma), due to affected parents (beta), and the probability that the heterozygote develops the trait (h). With mutational changes from the wild-type allele to the deleterious gene at a rate of alpha per generation, the equilibrium frequency of deleterious genes is approximately alpha/hs for 0 less than h less than or equal to 1 and square root alpha/s for h = 0, where s = gamma + beta(1 -- gamma)/2. Implications of the social selection model have been discussed for several diseases in man.     

The genetic-demographic approach in anthropological research. X. The dynamics of the sex-age structure of Khakass populations]

Social-economic remakings in Siberia are reflected in the economy of a rural inhabitant and the sex-age structure of the Khakass populations. The age average of the population increased from 26.7 years in 1954 up to 31.2 years in 1980. It has been established that the effectively reproductive size of a population (Ne) which takes into account its historical extent serves as a satisfactory estimate of the veritable (not single, instantaneous) size of a population.     

Genetic-demographic processes in urban populations of the Ukraine in the 90's. The marital structure of the Poltava population

Analysis of records of the marriages that were contracted in the city of Poltava revealed an increase in outbreeding between 1960 and 1985 in the Poltava population. This was expressed in increased ethnic diversity, proportion of interethnic marriages, migration range, and the parent-offspring and average marital distances, whereas the proportion of the indigenous ethnic group (Ukrainians) decreased. By 1995, outbreeding decreased: the ethnic composition of the population became more homogeneous (98% Slavic), the proportion of Ukrainians and the frequency of monoethnic marriages increased, and the migration range decreased. During the period studied, the population became more panmictic with respect to ethnicity and birthplace, with the social and professional subdivisions of the population remaining unchanged.     

Population dynamics of japanese serow in relation to social organization and habitat conditions. I. Stability of Japanese serow density in stable habitat conditions

The density of a Japanese serow (Capricornis crispus) population, which has been in stable habitat conditions and free from hunting and predation, was investigated by direct observation of serows at Kusoudomari (336 ha), Wakinosawa village, Aomori Prefecture, Japan, during 1977–89. The vegetation, composed of mature mixed forest ofThujopsis with deciduous trees (43.2%), secondary forest of deciduous trees (23.4%) and a plantation of coniferous trees (30.0%) showed little change during the study period. The serows were counted 17 times each winter for 14 consecutive years. The serow population maintained a stable density with a mean of 12.5 individuals km⁻² (SD=1.4) ranging from 8.6 to 14.6 km⁻². The ratio of the proportion of kids (<1 year old) to serows more than 1 year old decreased, but density did not decrease during the study period. Though extremely severe winters with heavy snowfall in 1984–86 caused a decline in serow density, the density recovered within a few years. It was considered that the stability of the serow density resulted mainly from the stable food supply and the lack of human disturbance, such as forest cutting in the habitat. Stable population density for a long period is probably related to the social organization of the serow.     

The Contribution of Social Behaviour to the Transmission of Influenza A in a Human Population

Variability in the risk of transmission for respiratory pathogens can result from several factors, including the intrinsic properties of the pathogen, the immune state of the host and the host''s behaviour. It has been proposed that self-reported social mixing patterns can explain the behavioural component of this variability, with simulated intervention studies based on these data used routinely to inform public health policy. However, in the absence of robust studies with biological endpoints for individuals, it is unclear how age and social behaviour contribute to infection risk. To examine how the structure and nature of social contacts influenced infection risk over the course of a single epidemic, we designed a flexible disease modelling framework: the population was divided into a series of increasingly detailed age and social contact classes, with the transmissibility of each age-contact class determined by the average contacts of that class. Fitting the models to serologically confirmed infection data from the 2009 Hong Kong influenza A/H1N1p pandemic, we found that an individual''s risk of infection was influenced strongly by the average reported social mixing behaviour of their age group, rather than by their personal reported contacts. We also identified the resolution of social mixing that shaped transmission: epidemic dynamics were driven by intense contacts between children, a post-childhood drop in risky contacts and a subsequent rise in contacts for individuals aged 35–50. Our results demonstrate that self-reported social contact surveys can account for age-associated heterogeneity in the transmission of a respiratory pathogen in humans, and show robustly how these individual-level behaviours manifest themselves through assortative age groups. Our results suggest it is possible to profile the social structure of different populations and to use these aggregated data to predict their inherent transmission potential.     

The return of the vole cycle in southern Finland refutes the generality of the loss of cycles through ‘climatic forcing’

Multiannual cycles in the abundance of voles and other animals have been collapsing in the last decades. It has been proposed that this phenomenon is ‘climatically forced’ by milder winters. We here consider the dynamics of bank and field voles during more than two decades in two localities (170 km apart) in southern Finland. Using wavelet analysis, we show that a clear 3‐year cycle disappeared in the mid 1990s. However, the vole cycle returned in both localities after about 5 years despite winters becoming increasingly milder. In both localities, vole cycles were mainly determined by bank voles after the period of noncyclic dynamics, whereas field voles were dominant before this irregularity. Wavelet coherency analysis shows that spatial synchrony temporarily broke down during the period of noncyclic dynamics, but was fully restored afterwards. The return of the cycle despite ongoing rapid climate change argues against ‘climatic forcing’ as a general explanation for loss of cycles. Rather, the population‐dynamical consequences of climate change may be dependent on the local species composition and mechanism of delayed density dependence.     

The genetic-demographic approach in anthropological research. XI. The structure of the reproductive behavior of Khakass families]

A detailed analysis of chronological intervals typical of reproduction process has been carried out in rural Khakassian populations to reveal the mechanisms of natural selection and gene drift. It is shown that the process of reproduction is connected with cultural traditions and economical activity of a population under study. The main characteristics of reproductive family behavior (the whole number of children and sex ratio, birth interval ect.) play a very important role in family and kin relationships, age, sex and marriage-migration structure of the population.     

The history and control of the pine beauty moth, Panolis flammea (D. & S.) (Lepidoptera: Noctuidae), in Scotland from 1976 to 2000

1 The pine beauty moth, Panolis flammea, has been a serious pest of lodgepole pine plantations in Scotland since 1976. It historically feeds on native Scots pine throughout Europe but population levels of P. flammea on this host have never been high enough to cause tree mortality in the U.K. 2 This paper reviews recent advances in the biology of the pest and documents control programmes from 1976 to 1999. 3 There has been practically uninterrupted population monitoring of P. flammea from 1977 to the present day in Scottish lodgepole pine plantations. Intervention with chemical spraying has often been necessary. 4 The population data suggest that populations of P. flammea may have had a cyclic pattern over the monitoring period, with outbreaks occurring at regular intervals of between 6 and 7 years. 5 The amplitude of population cycles was large during the 1970s and 1980s, but has dampened in recent years. Natural enemies are believed to contribute to this trend. Fungal disease, specifically, appears to have had a greater effect on pest populations in recent years than in the past and is suggested to have contributed significantly to the population dynamics observed since 1990.     

"社会-经济-自然复合生态系统"中的鼠害治理

在自然生态系统中,鼠类并非完全有害,作为生态系统中的一个组成部分和物流与能流的一环,有其存在的必然性。只有在与人类的生活和生产发生冲突时,鼠类才表现出其危害,生态系统的失衡是鼠类暴发成灾最根本的原因。目前,害鼠对工农业生产造成严重的危害,并威胁着人们的身体健康,害鼠防治的异化则对生态环境造成严重的影响。对鼠害的治理是一项社会性的工程,当地政府的政策法令、组织管理、人们的科学化素质以及科技普及程度,对害鼠的控制有着重要的作用。从长远发展来讲,随着社会的进步,经济的发展,人民生活水平的提高,害鼠种群数量将会受到控制而趋于下降。但中短期而言,社会经济建设的某些活动可能引发局部或大面积害鼠种群的暴发。因此在实施那些措施时,若能注意害鼠种群的发生发展,或对有关项目可能对鼠类生存环境的影响进行预测,并采取有效措施控制害鼠种群,将会减少害鼠带来的各种损失,更有利于我们的经济建设。由此提出,可适时地采用“社会—经济—自然复合生态系统”的思维,并关注目前社会经济活动中重大举措对鼠类群落的影响,科学地制定鼠害控制对策。     

The use of non-metrical variations of the cranium in the study of Scandinavian population movements

The incidences of 30 non-metrical skull variants have been determined in 21 samples of crania from Scandinavia, Iceland and the British Isles. The samples have been compared to give Estimates of Divergence which are assumed to represent degrees of genetical affinity between them. In general these estimates are in accordance with known population movements in the area and also with genetical affinities determined from other systems. One bizarre result emphasizes the importance of caution in interpreting genetical distances found by this or similar methods. It is concluded that this method is a useful aid in human population studies.     

Socio-Economic Instability and the Scaling of Energy Use with Population Size

The size of the human population is relevant to the development of a sustainable world, yet the forces setting growth or declines in the human population are poorly understood. Generally, population growth rates depend on whether new individuals compete for the same energy (leading to Malthusian or density-dependent growth) or help to generate new energy (leading to exponential and super-exponential growth). It has been hypothesized that exponential and super-exponential growth in humans has resulted from carrying capacity, which is in part determined by energy availability, keeping pace with or exceeding the rate of population growth. We evaluated the relationship between energy use and population size for countries with long records of both and the world as a whole to assess whether energy yields are consistent with the idea of an increasing carrying capacity. We find that on average energy use has indeed kept pace with population size over long time periods. We also show, however, that the energy-population scaling exponent plummets during, and its temporal variability increases preceding, periods of social, political, technological, and environmental change. We suggest that efforts to increase the reliability of future energy yields may be essential for stabilizing both population growth and the global socio-economic system.     

Influence of slope orientation on sex ratio and size distribution in a dioecious plant <Emphasis Type="Italic">Bursera fagaroides</Emphasis> var. <Emphasis Type="Italic">purpusii</Emphasis> (Brandeg.) McVaugh and Rzed. (Burseraceae)

It has been hypothesized that environmental variability can influence the sex ratio of a plant population, and it has been observed that in stressful environments, male plants are more abundant than females. However, it is unknown whether this is due to differential mortality rates between males and females. In this study, we analyzed sex ratio, mortality, and size distribution in a population of the neotropical tree/bush Bursera fagaroides in two different environments (east- and west-oriented slopes) over a 10-year period. We determined that the sex ratio favored males in the more stressful environment (east-facing slope) and that females were significantly larger in the less stressful environment (west-facing slope). Despite a significant difference in size between sexes by slope aspect, the difference in sex ratio cannot be explained by slope or by mortality during the 10 years of observation.     

The kidney concentrating function in the posttraumatic period: the role of the thyroid hormones and vasopressin]

The influence of thyroid hormones and vasopressin on lipid peroxidation (LP) in the rat kidneys in the posttraumatic period has been investigated. The rats with more pronounced disturbances of renal concentration mechanisms had a more increased LP, especially in the renal cortex. It is typical, that in some cases vasopressin levels did not correlate with the values of concentration index. A decrease in the affinity of the collecting duct cells to vasopressin may be a disturbance of renal concentration mechanisms in the posttraumatic period. It is found, that the character of thyroid hormones action on LP in renal tissue can be determined by tri- and tetraiodthyronine ratio.