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481.
Rosa M. Pintó M. Isabel Costafreda Francisco J. Pérez-Rodriguez Lucía D’Andrea Albert Bosch 《Food and environmental virology》2010,2(3):127-135
Hepatitis A is the most common among all hepatitis worldwide in spite of an efficient vaccine and improved hygiene. Shellfish-borne
outbreaks are still of major concern causing hundreds of cases and huge economical losses in the present context of global
food trade. Hepatitis A virus (HAV) is a unique picornavirus with many differences in its molecular biology including both
its incapacity to induce the inhibition of the cellular protein synthesis and a highly biased and deoptimized codon usage
with respect the cell. The final goal of this intriguing strategy seems to be the need for a fine-tuning control of the translation
kinetics, particularly at the capsid coding region, and the underlying mechanism is the use of a right combination of common
and rare codons to allow a regulated ribosome traffic rate thus ensuring the proper protein folding. Capsid folding is critical
to warrant a high environmental stability for a virus transmitted through the fecal–oral route with long extracorporeal periods. 相似文献
482.
A methodology for identifying volatile organic compounds (VOC) and determining air quality of indoor air has been developed. The air samples are collected using pump samplers by the inhabitants when they perceive odorous and/or discomfort episodes. Glass multi-sorbent tubes are connected to the pump samplers for the retention of VOC. The analysis is performed by automatic thermal desorption (ATD) coupled with gas chromatography-mass spectrometry (GC/MS). This methodology can be applied in cases of sick building syndrome (SBS) evaluation, in which building occupants experience a series of varied symptoms that appear to be linked to time spent in the building. Chemical pollutants concentrations (e.g., VOC) have been described to contribute to SBS. To exemplify the methodology, a qualitative determination and an evaluation of VOC present were performed in a dwelling where the occupants experienced the SBS symptoms. Higher total VOC (TVOC) value was detected in episodes in indoor air (1.33 ( 1.53 mg/m3) compared to outdoor air (0.71 ( 0.46 mg/m3). The concentrations of individual VOCs, such as ethanol, acetone, isopropanol, 1-butanol, acetic acid, acetonitrile and 1-metoxy-2-propanol, were also higher than the expected for a standard dwelling. The external source of VOC was found to be a not declared activity of storage and manipulation of solvents located at the bottom of a contiguous building. 相似文献
483.
Rao D Ceballos Fernandez O Castañeda-Barbosa E Díaz-Fleischer F 《Die Naturwissenschaften》2011,98(8):699-703
Most orb-web spiders face downwards in the web. A downward orientation has been proposed to be the optimal strategy because
spiders run faster downwards and thus can catch prey quicker. Consequently, orb-web spiders also extend their web in the lower
part, leading to top-down web asymmetry. Since the majority of orb-web spiders face downwards, it has been difficult to test
the effect of orientation on prey capture and web asymmetry. In this study, we explored the influence of reverse orientation
on foraging efficiency and web asymmetry in Verrucosa arenata, a neotropical orb-web spider that faces upwards in the web. We show that reverse orientation does not imply reverse web
asymmetry in this species. V. arenata spiders captured more prey in the lower part of the web but more prey per area on the upper part. The average running speeds
of spiders did not differ between upward and downward running, but heavier spiders took longer to capture prey while running
upwards. We discuss these findings in the context of foraging efficiency and web asymmetry. 相似文献
484.
Francisco J. Abascal Manuel Quintans Ana Ramos-Cartelle Jaime Mejuto 《Marine Biology》2011,158(5):1175-1184
Nine individuals of shortfin mako, Isurus oxyrinchus, were tracked in the southeastern Pacific Ocean, off northern Chile, by means of pop-up satellite archival tags. No common
pattern was observed in their trajectories, apart from a movement onshore of all the fish tracked during June–August. The
average estimated rate of movement was of c. 27 km day−1. Data were collected and processed for a total of 341 days, including 33 days for one recaptured fish specimen, allowing
high-resolution archived data to be downloaded. The fish spent most of their time in the mixed layer but undertook dives down
to 888 m. Ambient temperatures ranged between 4.6 and 24.1°C, and the sea surface temperatures recorded ranged from 13.4 to
24.1°C during the study period. No clear diel pattern in depth behavior was observed, but mean vertical distribution was deeper
during the daytime. Moreover, a foraging pattern, consisting of rapid descents below the thermocline followed by slower ascents,
was generally observed during daylight hours. Dissolved oxygen concentration and water temperature seem to be the main factors
affecting the vertical range of the species in the area. This is the first study on electronic tagging of the shortfin mako
in the southeastern Pacific Ocean and covers the longest total tracking period reported so far for this species. 相似文献
485.
Núñez Vázquez EJ Lizarraga IG Schmidt CJ Tapia AC Cortes DJ Sandoval FE Tapia AH Guzman JJ 《Journal of environmental biology / Academy of Environmental Biology, India》2011,32(4):413-423
Historical documents and classic works together with recent specialized literature have described Harmful Algal Blooms (HABs) in the Gulf of California. This is a review of HABs impact (qualitative and quantitative) during the last decades in the Gulf of California on wild (mammals, birds, fishes, and invertebrates) and cultured animals (shrimps and fishes). Microalgal species responsible of noxious effects are Noctiluca scintillans, Cochlodinium polykrikoides, Gymnodinium catenatum, Prorocentrum minimum, Akashiwo sanguinea, Chattonella subsalsa Ch. marina, Chattonella sp., Heterocapsa sp., Dinophysis sp., Fibrocapsa japonica, Heterosigma akashiwo, Thalassiosira sp., Chaetoceros spp., Pseudo-nitzschia australis, P fraudulenta, Pseudo-nitzschia sp., Trichodesmium erythraeum and ScSchizotrix calcicola. Emphasis is given to the necessity to continue with interdisciplinary studies in oceanography, ecology, toxicology and toxinology interrelated with biomedical sciences such as physiology, pathology, epidemiology and animal health. 相似文献
486.
Landscape--wildfire interactions in southern Europe: implications for landscape management 总被引:5,自引:0,他引:5
Moreira F Viedma O Arianoutsou M Curt T Koutsias N Rigolot E Barbati A Corona P Vaz P Xanthopoulos G Mouillot F Bilgili E 《Journal of environmental management》2011,92(10):2389-2402
Every year approximately half a million hectares of land are burned by wildfires in southern Europe, causing large ecological and socio-economic impacts. Climate and land use changes in the last decades have increased fire risk and danger. In this paper we review the available scientific knowledge on the relationships between landscape and wildfires in the Mediterranean region, with a focus on its application for defining landscape management guidelines and policies that could be adopted in order to promote landscapes with lower fire hazard. The main findings are that (1) socio-economic drivers have favoured land cover changes contributing to increasing fire hazard in the last decades, (2) large wildfires are becoming more frequent, (3) increased fire frequency is promoting homogeneous landscapes covered by fire-prone shrublands; (4) landscape planning to reduce fuel loads may be successful only if fire weather conditions are not extreme. The challenges to address these problems and the policy and landscape management responses that should be adopted are discussed, along with major knowledge gaps. 相似文献
487.
The abundance of exotic plants is thought to be limited by competition with resident species (including plants and generalist herbivores). In contrast, observations in semiarid Chile suggest that a native generalist rodent, the degu (Octodon degus), may be facilitating the expansion of exotic annual plants. We tested this hypothesis with a 20-year data set from a World Biosphere Reserve in mediterranean Chile. In this semiarid environment, rainfall varies annually and dramatically influences cover by both native and exotic annual plants; degu population density affects the composition and cover of exotic and native annual plants. In low-rainfall years, cover of both native and exotic herbs is extremely low. Higher levels of precipitation result in proportional increases in cover of all annual plants (exotic and native species), leading in turn to increases in degu population densities, at which point they impact native herbs in proportion to their greater cover, indirectly favoring the expansion of exotic plants. We propose that bottom-up control of consumers at our site results in top-down indirect facilitation of invasive annual herbs, and that this pattern may be general to other semiarid ecosystems. 相似文献
488.
Devesa-Rey R Díaz-Fierros F Barral MT 《Environmental monitoring and assessment》2011,179(1-4):371-388
The metals distribution in the bed sediments of the Anllóns River was studied, with special emphasis on the evaluation of the metal distribution as a function of the granulometric fraction chosen for the analysis. Statistical significant differences between the distribution of K, Ca, Cr, Mn, As, Rb, Sr and Nb in the bulk (<2 mm) and fine fraction (<63 μm) were not found. Fe, Ni, Cu, Ga, Zr, Zn and Pb commonly appear in higher concentrations in the fine fraction, whereas Ti appears in higher concentrations in the bulk fraction. In general, it was observed that contamination phenomena tend to equalise the concentrations of both fractions, and this was mainly explained as the result of two processes. First, the formation of coatings over sands and, second, the formation of large aggregates (pseudo-sands) at sites located over basic rocks, whose chemical behaviour is closer to that of clays and could be responsible for significant adsorption processes. Normalisation techniques to evaluate contamination were applied by testing Nb, Sr, Rb or Ga as normaliser elements and by using crustal or shale average values for background concentrations. The most satisfactory result was obtained when using shale average values and Ga as the normaliser element. Arsenic was identified as the main contaminant of the basin, exceeding in all cases the low-effect reference values proposed by sediment quality guidelines and in two cases the medium-effect reference values. These sites were identified by multivariate techniques, which allow differentiating site 10 as affected by anthropogenic inputs related to past mining activities. 相似文献
489.
Alcázar P García-Mozo H Trigo Mdel M Ruiz L González-Minero FJ Hidalgo P Díaz de la Guardia C Galán C 《Journal of environmental monitoring : JEM》2011,13(9):2502-2510
Platanus is a major cause of pollen allergy in many Spanish cities. The present paper reports an analysis of Platanus pollen season throughout the Andalusia region (southern Spain), which has among the highest pollen counts and the highest incidence of Platanus-related allergies in Europe. The main aim was to analyze pollen season trends from 1992 to 2010 in Andalusia; models were also constructed to forecast the start of the season. Daily pollen counts were recorded using Hirst-type volumetric spore-traps. Pollen season start-dates were very similar at all sites, usually occurring in March. The pollen season was delayed over the study period. The Pollen-season duration and Pollen index generally increased throughout the study period. The starting date for temperature accumulation was around the 10th February, although the threshold temperatures varied by site. The regional model for Andalusia failed to provide sufficiently accurate results compared with sub-regional or local models. For modeling purposes, three sub-regions are recommended: Inland, East Coast and West Coast. 相似文献
490.
Fast climate changes in the western Antarctic Peninsula are reducing krill density, which along with increased fishing activities in recent decades, may have had synergistic effects on penguin populations. We tested that assumption by crossing data on fishing activities and Southern Annular Mode (an indicator of climate change in Antarctica) with penguin population data. Increases in fishing catch during the non-breeding period were likely to result in impacts on both chinstrap (Pygoscelis antarcticus) and gentoo (P. papua) populations. Catches and climate change together elevated the probability of negative population growth rates: very high fishing catch on years with warm winters and low sea ice (associated with negative Southern Annular Mode values) implied a decrease in population size in the following year. The current management of krill fishery in the Southern Ocean takes into account an arbitrary and fixed catch limit that does not reflect the variability of the krill population under effects of climate change, therefore affecting penguin populations when the environmental conditions were not favorable.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01386-w) contains supplementary material, which is available to authorized users. 相似文献