Search results for "Population growth"
showing 10 items of 109 documents
Effects of a mixture of vegetable and essential oils and fatty acid potassium salts on Tetranychus urticae and Phytoseiulus persimilis.
2008
Laboratory trials were carried out to evaluate the toxicity and the influence of a commercial mixture of vegetal, essential oils, and potassium salts of fatty acids (Acaridoil 13SL) on the population growth rate (r(i)--instantaneous rate of increase) of two mite species, the phytophagous Tetranychus urticae Koch and the predator Phytoseiulus persimilis Athias-Henriot. A residue of 1.3 mg/cm(2) of pesticide solution was harmless for Ph. persimilis eggs, while a moderate mortality of eggs and of larvae from treated eggs of T. urticae, was observed (53.8%). The pesticide also caused a delay in the postembryonic development of the tetranychid. Moreover, 83.4% mortality was reported for treated …
Updated 24-year trend of Type 1 diabetes incidence in children in Poland reveals a sinusoidal pattern and sustained increase
2017
AIMS To present the incidence trend for Type 1 diabetes in Polish children aged 0-14 years, updated using data collected during 2005-2012, and assess the reliability of the predictive model constructed previously using the 1989-2004 database. METHODS Children aged < 15 years with newly diagnosed Type 1 diabetes are recorded prospectively (EURODIAB criteria) in several regional registers in Poland. Age- and gender-standardized incidence rates for Type 1 diabetes were calculated per 100 000 persons/year. Incidence rates were analysed in terms of the dependency on age, gender, geographical region and population density. Incidence rate trends over time were modelled using generalized linear mod…
Beyond lifetime reproductive success: the posthumous reproductive dynamics of male Trinidadian guppies
2013
In semelparous populations, dormant germ banks (e.g. seeds) have been proposed as important in maintaining genotypes that are adaptive at different times in fluctuating environments. Such hidden storage of genetic diversity need not be exclusive to dormant banks. Genotype diversity may be preserved in many iteroparous animals through sperm-storage mechanisms in females. This allows males to reproduce posthumously and increase the effective sizes of seemingly female-biased populations. Although long-term sperm storage has been demonstrated in many organisms, the understanding of its importance in the wild is very poor. We here show the prevalence of male posthumous reproduction in wild Trini…
A trade-off between sexual signalling and immune function in a natural population of the drumming wolf spider Hygrolycosa rubrofasciata.
2005
The field of ecological immunology is ultimately seeking to address the question ‘Why is there variation in immune function?’ Here, we provide experimental evidence that costs of ubiquitous sexual signals are a significant source of variation in immune function. In the mating season, males of the wolf spider Hygrolycosa rubrofasciata drum against dry leaves while wandering around the habitat searching for receptive females. According to a previous study, the male metabolic rate during the drumming increases 22-fold compared to the resting metabolic rate. In the present study, we examined whether investment in costly courtship drumming decreases male immune function in a wild population of H…
Determinants of migratory flow in Europe: A fuzzy-set approach
2018
Abstract This article examines the variables that explain immigrants' decisions to remain in 18 European countries at three key stages of the European economic cycle: 2006 (economic boom), 2009 (the height of the economic and financial crisis), and 2014 (beginning of recovery). Population variables, environmental and health service variables, and economic variables were considered. Fuzzy-set qualitative comparative analysis (fsQCA) was used to conduct the analysis. The findings indicate that immigration behavior differs according to the stage of the economic cycle. When the economic cycle is in a favorable stage (boom and economic recovery), the GDP growth and land surface area of the recei…
Mitochondrial DNA haplotype frequencies in natural and experimental populations of Drosophila subobscura.
1998
Abstract The evolution of Drosophila subobscura mitochondrial DNA has been studied in experimental populations, founded with flies from a natural population from Esporles (Majorca, Balearic Islands, Spain). This population, like other European ones, is characterized by the presence of two very common (&gt;96%) mitochondrial haplotypes (called I and II) and rare and endemic haplotypes that appear at very low frequencies. There is no statistical evidence of positive Darwinian selection acting on the mitochondrial DNA variants according to Tajima's neutrality test. Two experimental populations, with one replicate each, were established with flies having a heterogeneous nuclear genetic back…
Does investor attention influence water companies’ stock returns?
2020
Abstract The potential impacts of climate change and population growth are having serious effects on the energy and agricultural industries, which might compromise water availability. Water scarcity requires the global water industry to examine the rapidly changing market and, together with public initiatives, make innovative investments to guarantee better water management models. Therefore, from an investor's perspective, it is important to understand what might influence water companies’ stock returns. This paper analyzes how the energy and agriculture industries and the growing environmental awareness of investors influence water companies’ stock returns. Panel data on the monthly stock…
Impact of 70 years urban growth associated with heavy metal pollution
2014
Historical trends in trace element deposition were analyzed using herbaria specimens. We determined Al, Fe, Mg, Mn, Ca, Na, P, K, S, As, Cd, Cr, Cu, Ni, Pb and Zn contents in leaves of eight specimens collected in 1941. To assess changes, we collected the same plants from a botanical garden in 2012. The concentrations of major elements showed large species variability. However, temporal trends were predominately detected for heavy metals. The Cd, Ni and Cr contents in the 2012 leaves were 10, 13 and 16 times higher, respectively, than in 1941. Urban activities have substantially raised the levels of these metals in urban atmospheres due to changes in human activities over 70 years of urban …
Territorial defense, territory size, and population regulation.
2005
The carrying capacity of an environment is determined partly by how individuals compete over the available resources. To territorial animals, space is an important resource, leading to conflict over its use. We build a model where the carrying capacity for an organism in a given environment results from the evolution of territorial defense effort and the consequent space use. The same evolutionary process can yield two completely different modes of population regulation. Density dependence arises through expanding and shrinking territories if fecundity is low, breeding success increases gradually with territory size, and/or defense is cheap. By contrast, when fecundity is high, breeding suc…
Residential Change and Socio-demographic Challenges for Large Housing Estates in Riga, Latvia
2019
Large housing estates from the socialist era are a characteristic feature of the built environment in the cities of Central and Eastern Europe. Many urban researchers are increasingly interested in residential changes in these areas, showing how demographic and socioeconomic processes interact with the decline or upgrading of this distinct type of housing. In Europe, the debate concerning large housing estates is largely related to a declining and ageing population, as well as to housing conditions. In Latvia, the underdeveloped housing market and the massive privatisation of the housing stock to sitting tenants have contributed, since the late-Soviet period, to inherited socio-spatial stru…