RESUMO
The western gray whale population is endangered with approximately 175 individuals and 33 known reproductive females. Photo-identification studies were conducted from 2002-2017 during the gray whale foraging season off northeastern Sakhalin Island, Russia. Despite abundant prey resources, significant variation in whales' body condition, inter-birth intervals and calf survival have been documented with limited understanding of factors that account for the observed variability. We examine sea ice concentrations at their known foraging grounds to define the maximum duration of a "foraging season". We explore the relationship between foraging season length during a female's pregnancy and post-weaning calf survival and reproduction. Approximately 77% of the variation in calf survival, which ranged annually from 10-80%, was associated with the duration of the feeding season while the mother was pregnant. Poor body conditions and prolonged inter-birth intervals of western gray whales have also been documented to coincide with shorter duration in feeding seasons found in this study. These results imply that shorter foraging seasons are associated with reduced energy intake by physically limiting the number of days gray whales can forage, and thus sea ice conditions may be one limiting factor affecting growth rates of this endangered population of baleen whales.
Assuntos
Espécies em Perigo de Extinção/estatística & dados numéricos , Comportamento Alimentar , Camada de Gelo , Baleias/crescimento & desenvolvimento , Animais , Feminino , Cadeia Alimentar , Estágios do Ciclo de Vida , Exposição Materna , Densidade Demográfica , Gravidez , Federação Russa , Estações do Ano , Análise de SobrevidaRESUMO
It is shown that the impedance spectroscopy allows identification of the resistive switching mechanisms in complex composite structures. This statement was demonstrated on an example of organic based sandwich structures with a modified polymer matrix as an active element. The impedance spectroscopy scanning was performed for a series of intermediate states formed within the switching process. Analysis of the experimentally obtained impedance spectra shows that the electron transport is provided by delocalized charge carriers and proceeds via conducting filaments formed in a highly resistive matrix. The filament configuration changes during the switching. With the shift from isolating to conducting states, single isolated filaments are reorganized into a branched network.
RESUMO
This study has demonstrated that subjects of different "immune health" status also differ in the activity of the vegetative nervous system. Aerocryotherapy was shown to have stimulatory effect on the immune system and decreased the hyperactivity of the parasympathetic nervous system especially in people suffering immune insufficiency.
Assuntos
Sistema Nervoso Autônomo/fisiologia , Fenômenos Fisiológicos Cardiovasculares , Crioterapia/métodos , Imunidade Inata , Infecções Respiratórias/terapia , Viroses/terapia , Doença Aguda , Adulto , Interpretação Estatística de Dados , Humanos , Imunidade Celular/fisiologia , Nitrogênio/administração & dosagem , Nitrogênio/uso terapêutico , Infecções Respiratórias/imunologia , Infecções Respiratórias/fisiopatologia , Infecções Respiratórias/virologia , Resultado do Tratamento , Viroses/imunologia , Viroses/fisiopatologia , Adulto JovemRESUMO
The influence of constant magnetic field, power 7 T, and ultrasound, frequency 2, 4 and 8 MHz, on gametes, fertization, embryos and larvae of the sea urchin was studied. It was shown that magnetic field breaks the process of the gamete fusion but does not influence gametes, embryos, and larvae. Ultrasound impairs the motility of spermatozoa and larvae, prevents the fertilization, and breaks the embryonic development. It is assumed that the effect of the magnetic field is connected with the response of the cortical cytoskeleton, which consists of bundles of actin microfilaments. The rearrangement of the cortical cytoskeleton occurs during the first 20 minutes after the contact of sperm with the egg. Also there is effect of magnetic fields on calcium ions, which are liberated during the first seconds after gamete contact. The effect of the ultrasound is explained by a small increase in water temperature and cavitation process, which break celluar structures.