147 research outputs found
Weekday and weekend days correlates of sedentary time and screen-Based behaviors in children
The aim of this study was to compare weekday and weekend day correlates of sedentary time, as well as some specific screen-based behaviors, in a sample of 213 Spanish six to eleven year-olds (8.68 +/- 1.75 years), 76 boys (8.79 +/- 1.75 years) and 137 girls (8.73 +/- 1.75 years), who wore GT3X accelerometers for 7 days. Screen-based behaviors were reported by parents through questionnaires. Different potential correlates of sedentary time and screen-based behaviors were measured, and data were analyzed using general univariate linear models and multiple regression analysis. Results revealed high levels of screen-based behaviors, both during weekdays and weekend days. From the different significant correlates for each screen-based behavior analyzed, gender, age, hours of extracurricular PA, children''s MVPA and having a TV in the bedroom were identified as the main correlates in most of the behaviors analyzed. The design of multicomponent intervention programs seems advisable.
El objetivo de este estudio fue comparar diferentes determinantes de tiempo sedentario en dÃas entre semana y fines de semana, asà como determinados comportamientos de consumo de pantallas, en una muestra de 213 niños de 6 a 11 (8.68 ±1.75) años, 76 chicos (8.79 ±1.75) y 137 chicas (8.73±1.75). El tiempo sedentario fue determinado mediante acelerómetros GT3X, que los sujetos llevaron durante 7 dÃas. Los diferentes comportamientos de consumo de pantallas fueron reportados por los padres mediante cuestionarios. Se midieron diferentes potenciales determinantes de tiempo sedentario y consumo de pantallas, y los datos fueron analizados mediante modelos lineales univariantes y análisis de regresión múltiple. Los resultados revelaron altos niveles de consumo de pantallas, tanto en dÃas entre semana como en fines de semana. De los diferentes determinantes para cada tipo de comportamiento de consumo de pantallas analizados, el género, la edad, las horas de AF extracurricular, la AFMV de los niños y tener una TV en el dormitorio, fueron identificados como los principales. El diseño de programas multicomponentes de intervención parece recomendable
Biogeographic evaluation of the dragonflies and damselflies in the Eastern Iberian Peninsula
Insects are one of the most diverse groups of animals in terrestrial ecosystems, and are thus a good model system to study macrogeographic patterns in species' distributions. Here we perform a biogeographical analysis of the dragonflies and damselflies in the Valencian Country (Eastern Iberian Peninsula). We also compare the species present in this territory with those in the adjacent territories of Catalonia and Aragon, and with those present in the whole Iberian Peninsula. Furthermore, we update the list of species of dragonflies and damselflies in the Valencian territory (65 species), and discuss the current status of two of them: Macromia splendens and Lindenia tetraphylla. Our results highlight that the Valencian Country has a higher proportion of Ethiopian elements but a lower proportion of Eurosiberian elements than Catalonia and Aragon. We also emphasize the importance of volunteer work in providing new knowledge on this group of iconic insects, and the relevance of museum collections in preserving them. The role of climate change in the distribution of Odonata is also discussed
The adventure screenplay in William Goldman: the playful and the ironic in Butch Cassidy and the Sundance Kid and The Princess Bride
William Goldman is a North American novelist and screenwriter with more than fifty years in his professional career. This article aims to identify Goldman’s personal writing traits by focusing on Butch Cassidy and the Sundance Kid and The Princess Bride, which can be considered the most comprehensive and complete of all his screenplays. Apart from their differences, both scripts reveal the influence of the adventure narrative on William Goldman’s work and reflect the writer’s interest in ironically revising some of the conventions of film genre
Facultative endosymbionts of aphid populations from coastal dunes of the North Sea
Aphids establish symbiotic associations with a diverse assemblage of mutualistic bacteria. Some of them are not required for the host’s survival but still have a crucial impact on the biology and ecology of their host. Facultative symbionts may modify important host-life-history traits and affect the interactions of aphids with other members of the community. So far several species of aphid have been reported to occur in coastal dunes. Given the extreme environmental conditions of this type of habitat and the wide distribution along the European coast of some aphid species, these aphids would be expected to show variation in their facultative endosymbionts. However, there is currently no information available for these species. To address this question, we collected specimens from different populations of aphids (i.e. Schizaphis rufula, Laingia psammae and Rhopalosiphum padi) associated with the dune grass Ammophila arenaria in several locations of the North and the Irish Sea. By means of specific diagnostic PCR’s we checked for the presence of facultative bacterial endosymbionts in these populations. Results of this explorative assessment showed variation in the endosymbiont community according to species and location. All populations sampled along the North Sea coast were associated with the facultative endosymbiont Serratia symbiotica. Hamiltonella defensa was only detected in some specimens coming from the population in Het Zwin, Belgium. Regiella insecticola and the ¿-protobacteria X-type were only found associated with the population of Schizaphis rufula in De Panne, Belgium. Although further experiments are necessary to characterize the nature of these symbiotic relationships, our correlation analyses showed a significant co-occurrence of S. symbiotica with H. defensa and R. insecticola with X-type protobacteria suggesting reciprocal regulatory functions. No significant correlation was detected between the number of mummies (i.e. carcasses of aphids parasitized by wasps) and the occurrence of bacterial symbionts. The potential role of these symbionts in coastal dune ecosystems is discussed
Defensive insect symbiont leads to cascading extinctions and community collapse
This is the final version of the article. Available from Wiley via the DOI in this record.Animals often engage in mutualistic associations with microorganisms that protect them from predation, parasitism or pathogen infection. Studies of these interactions in insects have mostly focussed on the direct effects of symbiont infection on natural enemies without studying community-wide effects. Here, we explore the effect of a defensive symbiont on population dynamics and species extinctions in an experimental community composed of three aphid species and their associated specialist parasitoids. We found that introducing a bacterial symbiont with a protective (but not a non-protective) phenotype into one aphid species led to it being able to escape from its natural enemy and increase in density. This changed the relative density of the three aphid species which resulted in the extinction of the two other parasitoid species. Our results show that defensive symbionts can cause extinction cascades in experimental communities and so may play a significant role in the stability of consumer-herbivore communities in the field.The authors thank two anonymous reviewers for their helpful comments. This project was funded by the British Ecological Society (BES research grant #4682/5720 to EF), and by the Natural Environment Research Council (NERC grant #NE/K005650/1 to FJFvV). EF was funded by Marie Curie Intra-European Fellowship within the 7th European Community Framework Programme, FP7-PEOPLE-2012-IEF #329648
Average Structures of a Single Knotted Ring Polymer
Two types of average structures of a single knotted ring polymer are studied
by Brownian dynamics simulations. For a ring polymer with N segments, its
structure is represented by a 3N -dimensional conformation vector consisting of
the Cartesian coordinates of the segment positions relative to the center of
mass of the ring polymer. The average structure is given by the average
conformation vector, which is self-consistently defined as the average of the
conformation vectors obtained from a simulation each of which is rotated to
minimize its distance from the average conformation vector. From each
conformation vector sampled in a simulation, 2N conformation vectors are
generated by changing the numbering of the segments. Among the 2N conformation
vectors, the one closest to the average conformation vector is used for one
type of the average structure. The other type of the averages structure uses
all the conformation vectors generated from those sampled in a simulation. In
thecase of the former average structure, the knotted part of the average
structure is delocalized for small N and becomes localized as N is increased.
In the case of the latter average structure, the average structure changes from
a double loop structure for small N to a single loop structure for large N,
which indicates the localization-delocalization transition of the knotted part.Comment: 15 pages, 19 figures, uses jpsj2.cl
Percutaneous tibial nerve stimulation in patients with severe low anterior resection syndrome: randomized clinical trial
Treatment of low anterior resection syndrome (LARS) is challenging. Percutaneous tibial nerve stimulation (PTNS) can improve select bowel disorders. An RCT was conducted to assess the efficacy of PTNS compared with sham stimulation in patients with severe LARS
A meta-analysis of biological impacts of artificial light at night
This is the author accepted manuscript. The final version is available from Nature Research via the DOI in this record.Data availability:
All data generated or analysed during this study are available from the Dryad Digital Repository: https://doi.org/10.5061/dryad.wpzgmsbjnCode availability:
The computer code for the meta-analysis is available from the Dryad Digital Repository: https://doi.org/10.5061/dryad.wpzgmsbjnNatural light cycles are being eroded over large areas of the globe by the direct emissions and
the sky brightening that result from sources of artificial nighttime light. This is predicted to
affect wild organisms, particularly because of the central role that light regimes play in
determining the timing of biological activity. Although numerous empirical studies have
reported such effects, these have focussed on particular species or local communities and have
thus been unable to provide a general evaluation of the overall frequency and strength of
these impacts. Using a new database of published studies, we show that exposure to artificial
light at night induces strong responses for physiological measures, daily activity patterns and
life-history traits. We found particularly strong responses for hormone levels, the onset of
daily activity in diurnal species, and life-history traits such as offspring number, predation,
cognition and sea-finding (in turtles). There have been few studies so far on the impact of
artificial light at night on ecosystem functions. The breadth and often strength of biological
impacts we reveal highlights the need for outdoor artificial nighttime lighting to be limited to
the places and forms (such as timing, intensity, spectrum) in which it is genuinely required by
the people using it to minimise ecological impacts.Natural Environment Research Council (NERC
Activation of microglia in specific hypothalamic nuclei and the cerebellum of adult rats exposed to neonatal overnutrition
Much attention has been drawn to the possible involvement of hypothalamic inflammation in the pathogenesis of metabolic disorders, especially in response to a high-fat diet. Microglia, the macrophages of the central nervous system, can be activated by proinflammatory signals resulting in the local production of specific interleukins and cytokines, which in turn could exacerbate the pathogenic process. Because obesity itself is considered to be a state of chronic inflammation, we evaluated whether being overweight results in microglial activation in the hypothalamus of rats on a normal diet. Accordingly, we used a model of neonatal overnutrition that entailed adjustment of litter size at birth (small litters: four pups/dam versus normal litters: 12 pups/dam) and resulted in a 15% increase in bodyweight and increased circulating leptin levels at postnatal day 60. Rats that were overnourished during neonatal life had an increased number of activated microglia in specific hypothalamic areas such as the ventromedial hypothalamus, which is an important site for metabolic control. However, this effect was not confined to the hypothalamus because significant microglial activation was also observed in the cerebellar white matter. There was no change in circulating tumour necrosis factor (TNF) α levels or TNFα mRNA levels in either the hypothalamus or cerebellum. Interleukin (IL)6 protein levels were higher in both the hypothalamus and cerebellum, with no change in IL6 mRNA levels. Because circulating IL6 levels were elevated, this rise in central IL6 could be a result of increased uptake. Thus, activation of microglia occurs in adult rats exposed to neonatal overnutrition and a moderate increase in weight gain on a normal diet, possibly representing a secondary response to systemic inflammation. Moreover, this activation could result in local changes in specific hypothalamic nuclei that in turn further deregulate metabolic homeostasi
Decision Tree Classifiers for Star/Galaxy Separation
We study the star/galaxy classification efficiency of 13 different decision
tree algorithms applied to photometric objects in the Sloan Digital Sky Survey
Data Release Seven (SDSS DR7). Each algorithm is defined by a set of parameters
which, when varied, produce different final classification trees. We
extensively explore the parameter space of each algorithm, using the set of
SDSS objects with spectroscopic data as the training set. The
efficiency of star-galaxy separation is measured using the completeness
function. We find that the Functional Tree algorithm (FT) yields the best
results as measured by the mean completeness in two magnitude intervals: () and (). We compare the performance of the
tree generated with the optimal FT configuration to the classifications
provided by the SDSS parametric classifier, 2DPHOT and Ball et al. (2006). We
find that our FT classifier is comparable or better in completeness over the
full magnitude range , with much lower contamination than all but
the Ball et al. classifier. At the faintest magnitudes (), our classifier
is the only one able to maintain high completeness (80%) while still
achieving low contamination (). Finally, we apply our FT classifier
to separate stars from galaxies in the full set of SDSS
photometric objects in the magnitude range .Comment: Submitted to A
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