The purpose of this study was to characterize mountain river regimes in the Spanish Pyrenees and to assess the importance of snow accumulation and snowmelt on the timing of river flows. Daily streamflow data from 9 ga...
详细信息
The purpose of this study was to characterize mountain river regimes in the Spanish Pyrenees and to assess the importance of snow accumulation and snowmelt on the timing of river flows. Daily streamflow data from 9 gauging stations in the Pyrenees were used to characterize river regimes. These data were analyzed by hydrological indices, with a focus on periods when snow accumulation and snowmelt occurred. These results were combined with data on Snow Water Equivalent (SWE) (from measure- ments of depth and density of snow in the main river basins and also simulated by a process-based hydrological model), snowmelting (simulated by a process-based hydrological model), precipitation (from observations), and temperature (from observations). Longitude. and elevation gradients in the Pyrenees explain the transition of river regimes from those that mostly had low nival signals (in the west and at low elevations) to those that mostly had high nival signals (low winter runoff and late spring peakflow, in the east and at high elevations). Although trend analyses indicated no statistically signifi- cant changes, there was a trend of decreased nival signal over time in most of the analyzed rivers. Our results also demonstrated that snow processes cannot explain all of the interannual variability of river regimes, because the temporal distribution of liquid precipitation and tempera- ture play key roles in hydrography.
Seasonally frozen ground,mountain permafrost and cryogenic geomorphological processes are important components of the Pyrenean high *** work presents the results of a study on the distribution of frozen ground in a ma...
详细信息
Seasonally frozen ground,mountain permafrost and cryogenic geomorphological processes are important components of the Pyrenean high *** work presents the results of a study on the distribution of frozen ground in a marginal and paraglacial environment of temperate *** inventory was made of landforms and indicators of frozen ground,and frozen ground was mapped *** 2014 and 2016 ground temperatures and thermal regimes were monitored,basal temperatures of snow-cover(BTS)were measured and a thermal map was *** thermal behaviours were detected among different elevations and slope *** processes are the most widespread,in which frost weathering and nivation,together with gelifluction and cryoturbation,are the most efficient processes;the latter two are generally linked to the presence of frozen *** fall in air and ground temperatures with altitude,slope orientations,and snowpack thickness and evolution determine ground thermal *** the study area,three types of thermal regimes were established:climate-controlled,snowcover-controlled,and frozen *** frozen ground occurs across a broad range of elevation between 2650 and 3075 m asl,whereas possible permafrost only occurs above 2750 m asl.
Migratory connectivity describes the linkage between breeding and nonbreeding sites,having major ecological implications in birds:1 season influence the success of an individual or a population in the following *** st...
详细信息
Migratory connectivity describes the linkage between breeding and nonbreeding sites,having major ecological implications in birds:1 season influence the success of an individual or a population in the following *** studies on migratory connectivity have used large-scale approaches,often considering regional populations,but fine-scale studies are also necessary to understand colony *** lesser kestrel Falco naumanni,an insectivorous migratory raptor which form colonies during the breeding period,was considered to have strong connectivity based on regional ***,no small-scale studies on migratory connectivity have been ***,we GPS(Global Positioning System)-tracked 40 adult lesser kestrels from 15 different Spanish breeding colonies,estimating the overlap index between home ranges and the distance between their *** was found that lesser kestrels from the same breeding colony placed their nonbreeding areas at 347±281 km(mean±standard deviation)away from each other(range=23-990),and their home ranges over-lapped by 38.4±23.6%.No differences between intra-colony and inter-colony metrics were found,which suggests that lesser kestrels from the same breeding cluster do not overwinter together,but they spread out and mixed independently of the colony belonging throughout the nonbreeding range of the ***,this study highlights the importance of performing connectivity studies using fine-scale approaches.
The objective of this study was to evaluate supplemental organic chromium(Cr) to finishing lambs on growth performance, carcass characteristics, and meat quality. Eighteen Suffolk lambs(age(4.5±0.2) mon;(25.8±...
详细信息
The objective of this study was to evaluate supplemental organic chromium(Cr) to finishing lambs on growth performance, carcass characteristics, and meat quality. Eighteen Suffolk lambs(age(4.5±0.2) mon;(25.8±3.6) kg body weight(BW)) were randomly assigned to three levels of supplemental organic Cr(0.0, 0.2 and 0.4 mg kg^–1 dry matter(DM)) in a complete random design. Growth performance was evaluated for 70 d, and then lambs were slaughtered to study carcass characteristics and chemical composition of meat. Orthogonal contrasts were performed(contrast one-average level 0.2 ppm Cr vs. average level 0.4 ppm Cr; contrast two-level 0 vs. average levels(0.2+0.4) ppm Cr). Orthogonal polynomials were used to estimate the linear and quadratic effects of Cr concentrations. Growth and carcass performance were not affected by supplemental organic Cr. Muscle conformation and leg perimeter linearly increased(P〈0.05) as organic Cr level increased in the diet. Kidney fat decreased linearly(P〈0.05) as supplemental Cr increased. In Longissimus dorsi(LD), the ash content decreased linearly, and shear force(kg cm^–2) increased(P〈0.05) as organic Cr level increased in the diet. It is concluded that organic Cr did not affect growth performance, but it improved positively the muscle conformation, reduced kidney fat, whereas in LD there was an increment in shear force in finishing carcass lambs.
This study demonstrated the usefulness of very long-range terrestrial laser scanning(TLS) for analysis of the spatial distribution of a snowpack, to distances up to 3000 m, one of the longest measurement range reporte...
详细信息
This study demonstrated the usefulness of very long-range terrestrial laser scanning(TLS) for analysis of the spatial distribution of a snowpack, to distances up to 3000 m, one of the longest measurement range reported to date. Snow depth data were collected using a terrestrial laser scanner during 11 periods of snow accumulation and melting,over three snow seasons on a Pyrenean hillslopecharacterized by a large elevational gradient, steep slopes, and avalanche occurrence. The maximum and mean absolute snow depth error found was 0.5-0.6 and 0.2-0.3 m respectively, which may result problematic for areas with a shallow snowpack, but it is sufficiently accurate to determine snow distribution patterns in areas characterized by a thick snowpack. The results indicated that in most cases there was temporal consistency in the spatial distribution of thesnowpack, even in different years. The spatial patterns were particularly similar amongst thesurveys conducted during the period dominated by snow accumulation(generally until end of April), or amongst those conducted during the period dominated by melting processes(generally after mid of April or early May). Simple linear correlation analyses for the 11 survey dates, and the application of Random Forests analysis to two days representative of snow accumulation and melting periods indicated the importance of topography to the snow distribution. The results also highlight that elevation and the Topographic Position index(TPI) were the main variables explaining the snow distribution, especially during periods dominated by melting. The intra-and inter-annual spatial consistency of the snowpack distribution suggests that the geomorphological processes linked to presence/absence of snow cover act in a similar way in the long term, and that these spatial patternscan be easily identifiedthrough several years of adequate monitoring.
The aim of this work was to improve the thermal conductivity and electromagnetic shielding of the leakage proof phase change materials(PCMs),in which a polyrotaxane(PLR)was used as a support material to encapsulate PE...
详细信息
The aim of this work was to improve the thermal conductivity and electromagnetic shielding of the leakage proof phase change materials(PCMs),in which a polyrotaxane(PLR)was used as a support material to encapsulate PEG 1k or PEG 6k and MXene as multi-functional *** PCMs can be processed conveniently by a hot press and the PEG 1k containing samples showed excellent *** conducted a systematic evaluation of the phase transition behavior of the material,thermal conductivity and electromagnetic shielding performance ***,the PCMs achieved a high enthalpy values(123.9–159.6 J/g).The PCMs exhibited an increase of 44.3%,and 137.5%in thermal conductivity values with higher MXene content(5 wt%)for PLR-PEG6k and PLR-PEG1k,respectively,and show high shape stability and no leakage during and after phase *** introduction of MXene can significantly improve the electromagnetic shielding performance of PCM ***,higher conductive samples(samples which contain high MXene contents)offer a higher EMI SE shielding,reaching a maximum of 4.67 dB at 5.6 GHz for *** improvements solve the main problems of organic PEG based PCMs,thus making PLR-PEG-MXene based PCMs good candidates for thermoregulators of both solid-state disks and smart *** is worth pointing out that the sample PLR-1k-MX5 can decrease 4.3C of the reference temperature during cellphone ***,the temperature of the protecting sheet in the simulated solid state disk with PCM was significantly lower(showing a decreasing of 7.9℃)compared with the blank sample.
Deposition of the H2A.Z histone variant by the SWR1 complex (SWRI-C) in regulatory regions of specific loci modulates transcription. Characterization of mutations in Arabidopsis thaliana homologs of yeast SWRI-C has...
详细信息
Deposition of the H2A.Z histone variant by the SWR1 complex (SWRI-C) in regulatory regions of specific loci modulates transcription. Characterization of mutations in Arabidopsis thaliana homologs of yeast SWRI-C has revealed a role for H2A.Z exchange in a variety of developmental processes. Nevertheless, the exact composition of plant SWRI-C and how it is recruited to target genes remains to be established. Here we show that SWC4, the Arabidopsis homolog of yeast SANT domain protein Swc4/Eaf2, is a DNA-binding protein that interacts with SWR1-C subunits. We demonstrate that the swc4-1 knockout mutant is embryo- lethal, while SWC4 RNAi knockdown lines display pleiotropic phenotypic alterations in vegetative and repro- ductive traits, including acceleration of flowering time, indicating that SWC4 controls post-embryonic processes. Transcriptomic analyses and genome-wide profiling of H2A.Z indicate that SWC4 represses tran- scription of a number of genes, including the floral integrator FT and key transcription factors, mainly by modulating H2A.Z deposition. Interestingly, SWC4 silencing does not affect H2A.Z deposition at the FLC locus nor expression of this gene, a master regulator of flowering previously shown to be controlled by SWR1-C. Importantly, we find that SWC4 recognizes specific AT-rich DNA elements in the chromatin regions of target genes and that SWC4 silencing impairs SWRI-C binding at FT. Collectively, our data suggest that SWC4 regulates plant growth and development by aiding SWR1-C recruitment and modulating H2A.Z deposition.
AIM:To determine if the presence H pylori or its viru- lence affect toll-like receptor 4 (TLR4) and TLR5 mRNA expression levels. METHODS:For the in vivo assays, gastric biopsies were obtained from 40 patients and H py...
详细信息
AIM:To determine if the presence H pylori or its viru- lence affect toll-like receptor 4 (TLR4) and TLR5 mRNA expression levels. METHODS:For the in vivo assays, gastric biopsies were obtained from 40 patients and H pylori status was determined. For the in vitro assays, human gastric adenocarcinoma mucosal cells (AGS) were cultured in the presence or absence of twelve selected H pylori strains. H pylori strains isolated from culture-positive patients and selected strains were genotyped for cagA and vacA. The cDNA was obtained from mRNA extracted from biopsies and from infected AGS cells. TLR4 and TLR5 mRNA levels were examined by real-time PCR. RESULTS: The presence of H pylori did not affect the mRNA levels of TLR4 or TLR5 in gastric biopsies. The mRNA levels of both receptors were not influenced by the vacA status (P > 0.05 for both receptors) andthere were no differences in TLR4 or TLR5 mRNA levels among the different clinical presentations/histological fi ndings (P > 0.05). In the in vitro assay, the mRNA levels of TLR4 or TLR5 in AGS cells were not influenced by the vacAs1 status or the clinical condition as-sociated with the strains (P > 0.05 for both TLR4 and TLR5). CONCLUSION: The results of this study show that the mRNA levels of TLR4 and TLR5 in gastric cells, both in vivo and in vitro, are independent of H pylori colonization and suggest that vacA may not be a significant player in the first step of innate immune recognition mediated by TLR4 or TLR5.
The results presented here show for the first time the experimental demonstration of the fabrication of lossy mode resonance(LMR) devices based on perovskite coatings deposited on planar waveguides. Perovskite thin fi...
详细信息
The results presented here show for the first time the experimental demonstration of the fabrication of lossy mode resonance(LMR) devices based on perovskite coatings deposited on planar waveguides. Perovskite thin films have been obtained by means of the spin coating technique and their presence was confirmed by ellipsometry, scanning electron microscopy, and X-ray diffraction testing. The LMRs can be generated in a wide wavelength range and the experimental results agree with the theoretical simulations. Overall, this study highlights the potential of perovskite thin films for the development of novel LMR-based devices that can be used for environmental monitoring, industrial sensing, and gas detection, among other applications.
Laurel forests are quite relevant for biodiversity conservation and are among the island ecosystems most severely damaged by human *** the past,Canary laurel forests have been greatly altered by logging,livestock and ...
详细信息
Laurel forests are quite relevant for biodiversity conservation and are among the island ecosystems most severely damaged by human *** the past,Canary laurel forests have been greatly altered by logging,livestock and *** remains of laurel forests are currently protected in the Canary Islands(Spain).However,we miss basic information needed for their restoration and adaptive management,such as tree longevity,growth potential and responsiveness to natural and anthropogenic *** dendrochronological methods,we studied how forest dynamic is related to land-use change and windstorms in two well-preserved laurel forests on Tenerife *** cores were collected from over 80 trees per stand at three stands per *** used ring-width series to estimate tree ages and calculate annual basal area increments(BAI),cumulative diameter increases,and changes indicative of released and suppressed *** tree species were found in all stands,with Laurus novocanariensis,Ilex canariensis and Morella faya being the most common *** some individuals were over 100 years old,61.8%-88.9% of the trees per stand established between 1940 and 1970,coinciding with a post-war period of land abandonment,rural exodus and the onset of a tourism *** trees have shown growth rates larger than 1 cm diameter per year and most species have had increasing BAI trends over the past *** growth releases occurred after windstorms at both sites,but the effects of windstorms were site-dependent,with the 1958 storm affecting mainly the eastern tip of the island(Anaga massif)and the 1991 storm the western tip(Teno massif).Given the great ability of laurel forest trees to establish after land use cessation and to increase growth after local disturbances such as windstorms,passive restoration may be sufficient to regenerate this habitat in currently degraded areas.
暂无评论