Search results for "Spring"
showing 10 items of 600 documents
Social relations in older adults: Secular trends and longitudinal changes over a 16-year follow-up.
2010
Abstract Drawing on population studies in Finland, we investigated secular trends and longitudinal changes in social relations. The cohort comparison data comprised on 974 persons aged 65–69 years from three cohorts born between 1919 and 1939 and interviewed in 1988, 1996 and 2004. Longitudinal analyses were conducted for 635 persons aged 65–74 years over a 16-year follow-up at three measurement points. Social relations were studied on the basis of frequency seeing one's offspring, perceptions of the sufficiency of these contacts, and by asking whom the participants considered as their closest person and how often and in how many tasks they helped someone. The cohort comparisons showed that…
Contrasting the Effects of Maternal and Behavioral Characteristics on Fawn Birth Mass in White-Tailed Deer
2015
Maternal care influences offspring quality and can improve a mother’s inclusive fitness. However, improved fitness may only occur when offspring quality (i.e., offspring birth mass) persists throughout life and enhances survival and/or reproductive success. Although maternal body mass, age, and social rank have been shown to influence offspring birth mass, the inter-dependence among these variables makes identifying causation problematic. We established that fawn birth mass was related to adult body mass for captive male and female white-tailed deer (Odocoileus virginianus), thus maternal care should improve offspring fitness. We then used path analysis to identify which maternal characteri…
Centenarian offspring: A model for understanding longevity
2013
Abstract: A main objective of current medical research is to improve the life quality of elderly people as priority of the continuous increase of ageing population. This phenomenon implies several medical, economic and social problems because of dramatic increase in number of non autonomous individuals affected by various pathologies. Accordingly, the research interest is focused on understanding the biological mechanisms involved in determining the positive ageing phenotype, i.e. the centenarian phenotype. In achieving this goal the choice of an appropriate study models is fundamental. Centenarians have been used as an optimal model for successful ageing. However, this model shows several …
Centenarian Offspring as a Model of Successful Ageing
2019
The rapid increase in global average life expectancy, observed during the last years, due to improvements in sanitation and medical care, pushes the scientific community to understand the basis of the ageing process. In particular, in order to improve the life quality of elderly people, current ageing research is focused on the identification of biological mechanisms involved in successful ageing, a complex process influenced by several factors, including genetic, environment, and lifestyle. Centenarians, i.e., subjects who have reached ten or more decades of life, escaping the common age-related diseases, are the leading exponent of successful ageing. However, the rarity of such exponents,…
Gestational exposure to cocaine alters cocaine reward
2006
Exposure of the developing foetus to drugs of abuse during pregnancy may lead to persistent abnormalities of brain systems involved in drug addiction. Mice prenatally exposed to cocaine (25 mg/kg), physiological saline or non-treated during the last 7 days of pregnancy were evaluated in adulthood for the rewarding properties of cocaine (3, 25 and 50 mg/kg), using the conditioned place preference procedure. Dams treated with physiological saline gained significantly less weight over the course of gestation than controls; no other differences were observed in the maternal and offspring data. All the animals developed preference to 3 and 25 mg/kg of cocaine, but those treated prenatally with c…
Carbon degassing through karst hydrosystems of Greece
2022
Estimation of CO2 degassing from active tectonic structures and regional hydrothermal systems is essential for the quantification of presentday Earth degassing [Frondini et al., 2019 and references therein]. Due to the high solubility of CO2 in water, great amounts of deep inorganic carbon can be dissolved, transported, and released from regional aquifers. By applying a massbalance approach [Chiodini et al., 2000], different sources of the dissolved CO2 can be discriminated. The main source of degassing in Greece is concentrated in hydrothermal and volcanic areas. However, deep CO2 from active tectonic areas has not yet been quantified. A key point of this research is to investigate the pos…
The affect of contact force sensations on user performance in virtual assembly tasks
2007
International audience; Abstract The development of a realistic virtual assemblyenvironment is challenging because of the complexity of the physical processes and the limitation of available VRtechnology. Many research activities in this domain pri-marily focused on particular aspects of the assembly task such as the feasibility of assembly operations in terms of interference between the manipulated parts. The virtualassembly environment reported in this research is focusedon mechanical part assembly. The approach presented ad-dresses the problem of part-to-part contacts during themating phase of assembly tasks. The system describedcalculates contact force sensations by making their inten-s…
Maternal antibodies in a wild altricial bird: effects on offspring immunity, growth and survival
2006
1. In many animals immunity is not fully developed until adulthood but the young still need protection against various sets of pathogens. Thus, bird nestlings are highly dependent on antibodies received from their mother (in the eggs) during their rapid early growth period. The relationship between maternal immunity and the development of neonates' own immunity has been poorly studied. 2. It has been suggested that immune function plays an important part in mediating resource competition between different life-history traits, e.g. growth and reproduction. Maternal investment of antibodies has potentially permanent effects on offspring phenotype. Thus, the trade-offs between the immune funct…
Host-Plant Selection and Predation Risk for Offspring of the Parent Bug
1995
Herbivores, especially specialists, must adapt to characteristics of their host to survive and reproduce successfully (Hardin and Tallamy1992). If offspring survival among different hosts varies, natural selection should lead females to choose egg-laying sites where performance of the progeny will be highest. This is especially true when newly hatched larvae cannot move to another host (Singer 1986), or when searching for new hosts would cause heavy mortality (Singer and Mandracchia 1982). A number of studies have shown that females that search for oviposition sites respond to plant characteristics that are correlated with the nutritional quality of plants for their offspring (e.g., Myers 1…
THE EFFECTS OF MATING SYSTEM AND GENETIC VARIABILITY ON SUSCEPTIBILITY TO TREMATODE PARASITES IN A FRESHWATER SNAIL, LYMNAEA STAGNALIS
2004
The amount and distribution of genetic variability in host populations can have significant effects on the outcome of host-parasite interactions. We studied the effect of mating system and genetic variability on susceptibility of Lymnaea stagnalis snails to trematode parasites. Mating system of snails from eight populations differing in the amount of genetic variability was manipulated, and self- and cross-fertilized offspring were exposed to naturally occurring trematode parasites in a controlled lake experiment. Susceptibility of snails varied between populations, but mating-system treatment did not have a significant effect. Heterozygosity of snails was negatively correlated with the pro…