534 research outputs found
Environmental factors influence both abundance and genetic diversity in a widespread bird species.
Genetic diversity is one of the key evolutionary variables that correlate with population size, being of critical importance for population viability and the persistence of species. Genetic diversity can also have important ecological consequences within populations, and in turn, ecological factors may drive patterns of genetic diversity. However, the relationship between the genetic diversity of a population and how this interacts with ecological processes has so far only been investigated in a few studies. Here, we investigate the link between ecological factors, local population size, and allelic diversity, using a field study of a common bird species, the house sparrow (Passer domesticus). We studied sparrows outside the breeding season in a confined small valley dominated by dispersed farms and small-scale agriculture in southern France. Population surveys at 36 locations revealed that sparrows were more abundant in locations with high food availability. We then captured and genotyped 891 house sparrows at 10 microsatellite loci from a subset of these locations (N = 12). Population genetic analyses revealed weak genetic structure, where each locality represented a distinct substructure within the study area. We found that food availability was the main factor among others tested to influence the genetic structure between locations. These results suggest that ecological factors can have strong impacts on both population size per se and intrapopulation genetic variation even at a small scale. On a more general level, our data indicate that a patchy environment and low dispersal rate can result in fine-scale patterns of genetic diversity. Given the importance of genetic diversity for population viability, combining ecological and genetic data can help to identify factors limiting population size and determine the conservation potential of populations
Heat shock proteins and exercise
Uno de mecanismos que posee el organismo para contrarrestar la
ruptura de la homeostasis es la producción de proteínas de estrés o heat shock
proteins (HSP). Aumentos en la temperatura corporal, en la concentración de
Ca2+ y de ciertos corticoides así como disminuciones del pH, de la glucemia y
del glucógeno se presentan, junto a la isquemia, como los principales agentes
desencadenantes de la respuesta de HSP. La práctica de ejercicio físico
integra gran parte de estos factores, lo que provoca una clara liberación de
HSP muscular tras diferentes tipos de esfuerzos. Factores como la edad, el
género, el nivel de entrenamiento, la intensidad y el volumen del ejercicio
realizado o el tipo de fibra muscular, parecen tener una relación directa con las
adaptaciones biológicas relacionadas con las HSP. Son necesarios más
estudios para definir con mayor exactitud la función biológica de las HSP
vinculada con el ejercicio físico
Using whole body vibration to improve jump ability in young recreational sportmen
The whole body vibrations (WBV) it is nowadays one of the most widely used methods for improvingthe explosive strength. In this study, 12 subjects participating in recreational physical activity were allocated to a5 sets of 60 s training, using a frequency of 30 Hz, an amplitude of 2.5 mm. and a isometric position (110 °bending knees) on a Galileo Fitness ® (Novotech, Germany) platform. The results showed an increase in SJ(+1.76 ± 4.05 cm) and CMJ (+1.10 ± 3.20 cm) in the post-test conducted just after the vibration. The values of the post-test performed 30 minutes after the squat jump remained above the ones of pre-test but just below the ones of the immediate post-test (+0.42 ± 4.43 cm). By contrast the values in the counter movement jump drop below the pre-test ones (-0.12 ± 2.45 cm). Based on these data it seems that when the frequency is not high it is necessary to use a greater amplitude in order to achieve the desired effects. The effect achieved after the vibration is transient, not remaining after 30 minutes
Cardiovascular risk factors, caloric intake and practice of physical activity in college students. A preliminary study.
The aim of this investigation were to determine the level of physical activity practice and to define the presence of cardiovascular risk factors associated with body composition and caloric intake in college students. A total of 81 college students (38 and 41 females and males, respectively) were submitted to a complete evaluation that consisted of an analysis of food-intake behavior, measures of several body composition variables (height, weight, body mass index, fat and muscle mass, waist and hip circumferences, waist-hip ratio, and sum of 6 skinfolds), blood pressure assessment, and physical activity level calculation. The results show sex differences in blood pressure and body composition variables; although an optimal food-intake patterns, a high level of physical activity practice and the absence of cardiovascular risk factors seem to generate healthy profiles in this population. Key words:cardiovascular risk factors, food-intake patterns, physical activity, college students
Ergometric testing for top-level kayakers: validity and reliability of a discontinuous graded exercise test
E-Beam Generated Plasma Etching for Developing High-Reflectance Mirrors for Far-Ultraviolet Astronomical Instrument Applications
Astronomical space telescopes to study astrophysical phenomena from the far-ultraviolet (FUV) to the near infrared (NIR) will require mirror coatings with high reflectance over this entire spectral region. While coatings for the optical and NIR part of the spectrum are fairly well developed with proven performance, the FUV presents significant challenges. The U.S. Naval Research Laboratory (NRL) has developed a processing system based on an electron beam-generated plasma that provides for controlled fluorination and/or etching of surfaces with near monolayer precision and minimal changes to surface morphology. In this paper, we report recent results of samples treated in the NRL Large Area Plasma Processing System (LAPPS) where restoration of the high intrinsic reflectance in the FUV spectral range have been observed of aluminum (Al) mirrors protected with a magnesium di-fluoride (MgF2) overcoat. This paper will also extend these studies to other Al mirrors protected with aluminum tri-fluoride (AlF3) in order to realize the high intrinsic reflectance Al down to FUV wavelengths (100200 nm), while still maintaining the high reflectance in the optical and NIR spectral regions. Laboratory test data and optical diagnostic techniques used to verify surface scattering and durability of selected coatings will be presented. Finally, we will discuss the scalability of the LAPPS etching process in order to realize these high-reflectivity coatings on mirror segments as large as those proposed for the Large Ultraviolet, Optical, and Infrared (LUVOIR) astronomical telescope system (1+meter class)
Health related quality of life and depression in women with Fibromialgia syndrome: effects of a long-term exercise program
Reliabilty and validity of a discontinous graded exercise test on Dansprint® Ergometer
The aim of this study was to determine the validity and reliability of a graded exercise test on a specific kayak
ergometer (Dansprint®) in which certain physiological and technical parameters that can to define kayaking
performance were assessed. Fourteen male top-level kayak paddlers (all members of Spanish Kayaking National Team)
participated in this investigation. All subjects carried out two ergometric tests (Ergo1 and Ergo2) and one flat water test
(FWT) in random order. At anaerobic threshold (AnT) intensity, the results showed acceptable levels of reliability
(comparison between data of Ergo1 and Ergo2 tests) in the assessment of velocity (r=0.784; p=0.004), stroke frequency
(r=0.976; p<0.001), heart rate (r=0.964; p<0.001), and blood lactic acid concentration (r=0.899; p<0.001). Validity
coefficients showed a strong relationships between Ergo2 and FWT tests in all physiological and technical parameters
with the exception of velocity (r=0.498; p=0.121). It can be concluded that specific ergometry can be used to evaluate
and to prescribe training AnT intensities of top-level kayakers attending to parameters such us heart rate, whole blood
lactic acid concentration, and stroke frequency. Nevertheless, the training prescription through specific ergometry must
be taken cautiously when velocity is the parameter of reference
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