Search results for " Population"
showing 10 items of 1682 documents
Demographic characterization and genetic variability of the Girgentana goat breed by the analysis of genealogical data
2004
The aim of this paper is to present an overview of the actual Sicilian Girgentana population structure by the analysis ofgenealogical data. Statistics show that in 1983 the population consisted of 30,000 Girgentana goats; ten years lateralmost 98% of the entire Girgentana population disappeared. The remaining population consists of 461 individuals (134males and 327 females), with 368 living animals. The effective population size is 380 individuals. The inbreeding rate pergeneration was equal to 0.13%. The average estimated inbreeding level within the living male population was equal to0.8% (0-15%); and the average inbreeding level within the living female population was equal to 0.7% (0-31%…
Effects of air pollution on dementia over Europe for present and future climate change scenarios.
2020
The scientific literature is scarce when referring to the influence of atmospheric pollutants on neurodegenerative diseases for present and future climate change scenarios. In this sense, this contribution evaluates the incidence of dementia (Alzheimer's disease, AD, and dementia from unspecified cause, DU) occurring in Europe associated with the exposure to air pollution (essentially NO2 and PM2.5) for the present climatic period (1991-2010) and for a future climate change scenario (RCP8.5, 2031-2050). The GEMM methodology has been applied to air pollution simulations using the chemistry/climate regional model WRF-Chem. Present population data were obtained from NASA's Center for Socioecon…
Age-Structured Human Population Dynamics
2006
ABSTRACT A von Foerster-McKendrick model to study age-structured human population dynamics is presented in this paper. Forecasts of population density (population per age unit) depending on ages are possible using this model. The model consists of a quasi-linear first order partial differential equation for the dynamics of population density per age-unit (except for the zero-age), a boundary condition for the births flow at zero-age, and an initial condition for the population density at the initial instant. A general solution independent of the particular human-system under study is obtained based on some hypotheses about the mathematical structure of its input variables. The model has bee…
Modelling the Tactical Behaviour of the Australian Population in a Bushfire
2015
This paper is concerned with the development of an agent-based model of population behaviour during a bushfire, to form the basis of a simulator that will be used as a decision-support tool for emergency managers. To ensure the validity of the simulation results, it is essential that the model, and the underlying agent architecture, are as realistic as possible. After providing some context about recent bushfires in Victoria, Australia, we justify the need for a BDI (belief, desire, intention) agent architecture. Although some tools exist to support the integration of such agents in simulations, they are infrequently used. We therefore show how an existing methodology for modelling military…
Review of studies of polymorphic blood systems in the Aymara indigenous population from Bolivia, Peru, and Chile.
1995
A review was made of all studies available from the literature referring to polymorphic blood systems of South American Aymara Indians. 33 original papers published up to 1990 covering a period of 45 years were summarized. Aymara samples were considered from a total of 55 localities in Bolivia, Peru, and Chile. Gene frequencies were tabulated for 21 polymorphic genetic systems comprising blood groups (AB0, MNSs, P, Rh, Lu, K, Le, Fy, Jk, Di), erythrocyte enzyme groups (AcP, 6PGD, PGM1, AK, ADA, EsD), and plasma protein groups (Hp, Tf, Gc, Gm, Km). Weighted average and range over all Aymara samples were computed for each blood system and compared with corresponding mean value and range in So…
Electromagnetic Fields and Childhood Leukemia: Pooled Analyses of Two German Population-Based Case-Control Studies
1999
From 1992 to 1995 we conducted a population-based case-control study on residential magnetic fields and childhood leukemia in Lower Saxony, a region in northwestern Germany with 7.4 million inhabitants.1,2 Because of the rural character of this area, we detected elevated magnetic fields in only 1.5% of all dwellings. We therefore expanded the EMF-measurements to an ongoing case-control study on childhood leukemia in the capital of Germany, Berlin. We applied the same methods of exposure assessment, intending to pool the data of the two studies and to calculate combined risk estimates.3
On sampling error in evolutionary algorithms
2021
The initial population in evolutionary algorithms (EAs) should form a representative sample of all possible solutions (the search space). While large populations accurately approximate the distribution of possible solutions, small populations tend to incorporate a sampling error. A low sampling error at initialization is necessary (but not sufficient) for a reliable search since a low sampling error reduces the overall random variations in a random sample. For this reason, we have recently presented a model to determine a minimum initial population size so that the sampling error is lower than a threshold, given a confidence level. Our model allows practitioners of, for example, genetic pro…
Studies on the Sicilian populations ofAnacolia webbii(Mont.) Schimp. (Bartramiaceae, Bryophyta), rare moss in Europe
2014
New data on the distribution, biology, intra- and inter-population variability and conservation state of Sicilian populations of Anacolia webbii are provided. Two new localities are reported, so that total five fragmented populations occur in the island, all of them in a rather small area in the western part of the province of Palermo. They live on wet limestone or sandstone cliffs with base at 900–1200 m a.s.l. and N, N-NE aspect, within communities of Aceri campestris-Querco-ilicis sigmetum. The plants are particularly vigorous, but some data suggest a condition of vulnerability of the populations. In fact, in addition to specificity to a rare habitat on the island, a morphometric and all…
Biogeography of the smooth snake (Coronella austriaca): origin and conservation of the northernmost population
2014
Understanding historical range expansions and population demography can be crucial for the conservation and management of endangered species. In doing so, valuable information can be obtained regarding, for example, the identification of isolated populations, associations to particular habitats and distribution range shifts. As poikilotherms, snakes are vulnerable to environmental changes that can greatly shape their distribution ranges. Here we used mitochondrial data to elucidate the origin of the smooth snake population in Aland island, which is the northernmost location where the species is found. In Aland, we used mitochondrial and microsatellite data to fine-map its spatial genetic st…
Ecology of Cryptomonas at the chemocline of a karstic sulfate-rich lake
2001
In a study from October 1989 to January 1992, a dense population ofCryptomonas cf. erosa (maximum density 38 000 cells mL–1) consistently developed at the chemocline of Lake Arcas, central Spain,where sharp physical and chemical gradients occurred during stratification. This population developed following the establishment of vertical water stratification and declined when the lake was near autumnal mixis. Population growth in situ, attributable to photosynthetic adaptation to low light intensities rather than to phagotrophy, causes these algal maxima. The population densities and net growth rates of C. cf. erosa in situ were influenced by the coexisting phototrophic prokaryotes at the che…