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排序方式: 共有2769条查询结果,搜索用时 15 毫秒
921.
Marta Diez-Valcarce Petros Kokkinos Kirsi S?derberg Martijn Bouwknegt Kris Willems Ana Maria de Roda-Husman Carl-Henrik von Bonsdorff Maria Bellou Marta Hernández Leena Maunula Apostolos Vantarakis David Rodríguez-Lázaro 《Food and environmental virology》2012,4(2):73-80
In this study, the prevalence of different enteric viruses in commercial mussels was evaluated at the retail level in three European countries (Finland, Greece and Spain). A total of 153 mussel samples from different origins were analysed for human norovirus (NoV) genogroups I and II, hepatitis A virus (HAV) and hepatitis E virus (HEV). Human adenovirus (HAdV) was also tested as an indicator of human faecal contamination. A full set of controls (such as sample process control, internal amplification controls, and positive and negative controls) were implemented during the process. The use of a sample process control allowed us to calculate the efficiencies of extraction, which ranged from 79 to 0.5?%, with an average value of 10?%. Samples were positive in 41?% of cases, with HAdV being the most prevalent virus detected (36?%), but no significant correlation was found between the presence of HAdV and human NoV, HAV and HEV. The prevalences of human norovirus genogroup II, HEV and human NoV genogroup I were 16, 3 and 0.7?%, respectively, and HAV was not detected. The estimated number of PCR detectable units varied between 24 and 1.4?×?103?g?1 of digestive tract. Interestingly, there appeared to be a significant association between the type of mussel species (M. galloprovincialis) and the positive result of samples, although a complete overlap between country and species examined required this finding to be confirmed including samples of both species from all possible countries of origin. 相似文献
922.
Esquivel DM Wajnberg E do Nascimento FS Pinho MB Lins de Barros HG Eizemberg R 《Die Naturwissenschaften》2007,94(2):139-142
Six behavioural experiments were carried out to investigate the magnetic field effects on the nest-exiting flight directions
of the honeybee Schwarziana quadripunctata (Meliponini). No significant differences resulted during six experiment days under varying geomagnetic field and the applied static inhomogeneous
field (about ten times the geomagnetic field) conditions. A surprising statistically significant response was obtained on
a unique magnetic storm day. The magnetic nanoparticles in these bees, revealed by ferromagnetic resonance, could be involved
in the observed effect of the geomagnetic storm. 相似文献
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924.
ABSTRACTConceptualizing and analyzing collective policy learning processes is a major ongoing theoretical and empirical challenge. A key gap concerns the role of exogenous factors, which remains under-theorized in the policy learning literature. In this paper, we aim to advance the understanding of the role that exogenous factors play in collective learning processes. We propose a typology of exogenous factors (i.e. material, socioeconomic, institutional, discursive), and subsequently apply this in a comparative study of flood risk policymaking in two municipalities in the Netherlands. We find that exogenous factors are indeed essential for understanding collective learning in these cases, as the combined influence with endogenous factors can steer similar learning processes towards different learning products. We conclude our contribution by identifying two opportunities for further developing the collective learning framework, namely regarding the distinction of varying learning products, and the dynamics of exogenous factors over time. 相似文献
925.
The aim of this study is to analyze the structural relationships between strategy, environmental performance, and disclosure in view of the lack of research on these endogenous activities. To analyze these relationships, an environmental governance proxy consisting of five dimensions was developed for Brazilian companies. Hence, from an economic perspective, a trend is expected of companies disclosing more information and maintaining an environmental governance structure to avoid or reduce potential political costs. Using the structural equation technique, 573 Brazilian companies were analyzed. According to the results, the Brazilian companies’ mean compliance level with environmental governance practices is 49.2%. There is evidence of a positive association between the governance structure and the environmental management system (GSEM) as well as environmental performance (EP) and environmental disclosure levels (DISC). In addition, the level of environmental conflicts of interest a sector faces increased the need for environmental disclosure. Furthermore, the results demonstrate that the latent variables, GSEM and EP, exert direct and indirect positive effects on DISC. In other words, companies with more structured environmental management systems have obtained better performance indicators, and consequently, are more likely to feel encouraged to disseminate environmental information and to reduce political costs than is the case with other companies. 相似文献
926.
Edmilson F. de Oliveira-Filho Kennya G. S. Lopes Deivson S. Cunha Virginia S. Silva Clara N. Barbosa Daniel F. Brandespim José Wilton Pinheiro Junior Giovani R. Bertani Laura H. V. G. Gil 《Food and environmental virology》2017,9(3):256-259
Anti-HEV antibodies were detected in animals from abattoir and in farms from northeast Brazil. Our results suggest that HEV is highly disseminated in the swine population and might present a great risk to animal handlers and for consumption of raw or undercooked meat and meat products in northeast Brazil. 相似文献
927.
The selective forces imposed by primary receivers and unintended eavesdroppers of animal signals often act in opposite directions, constraining the development of conspicuous coloration. Because iridescent colours change their chromatic properties with viewer angle, iridescence offers a potential mechanism to relax this trade-off when the relevant observers involved in the evolution of signal design adopt different viewer geometries. We used reflectance spectrophotometry and visual modelling to test if the striking blue head coloration of males of the lizard Lacerta schreibeiri (1) is iridescent and (2) is more conspicuous when viewed from the perspective of conspecifics than from that of the main predators of adult L. schreibeiri (raptors). We demonstrate that the blue heads of L. schreiberi show angle-dependent changes in their chromatic properties. This variation allows the blue heads to be relatively conspicuous to conspecific viewers located in the same horizontal plane as the sender, while simultaneously being relatively cryptic to birds that see it from above. This study is the first to suggest the use of angle-dependent chromatic signals in lizards, and provides the first evidence of the adaptive function of iridescent coloration based on its detectability to different observers. 相似文献
928.
Estienney Marie Daval-Frerot Philippe Aho-Glélé Ludwig-Serge Piroth Lionel Stabile Pascal Gerbet Jean-Yves Rouleau Romain de Rougemont Alexis Belliot Gaël 《Food and environmental virology》2022,14(2):217-221
Food and Environmental Virology - Disinfection of hospital facilities and ambulances is an important issue for breaking the chain of transmission of viral pathogens. Hydrogen peroxide has provided... 相似文献
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930.