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41.
Anomalous transport of walleye pollock larvae linked to ocean and atmospheric patterns in May 1996 总被引:1,自引:0,他引:1
Larvae from a large aggregation of walleye pollock spawning in early spring in Shelikof Strait, Gulf of Alaska, are normally transported to the south-west in the vigorous Alaska Coastal Current. In the spring of 1996, anomalous winds resulted in unusually weak transport in the Shelikof Strait sea valley. The main aggregation of larval pollock in the Shelikof region was surveyed four times in 1996 over a period of about 40 days, including finer-scale sampling of the leading south-western edge of the larval distribution. The south-western edge of the larval distribution showed weak transport up the sea valley for a period of about 10 days, corresponding to the observations of currents, after which many larvae were transported over the shelf region to the west. These observations are unique in over 15 years of monitoring larval transport patterns and demonstrate how anomalous weather, and hence current patterns, influence variability in larval transport. 相似文献
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A complex of events and factors, pertinent to a specific insect and insecticide, governs the development of resistance to
insecticides. In Israel, resistance to conventional and novel insecticides occurred in insect pests such asBemisia tabaci andSpodoptera littoralis (that damage agricultural crops),Tribolium castaneum and other flour beetles (that contaminate stored products), andPediculus humanus spp., house flies and mosquitoes (that threaten public health). In the mid-1980s an insecticide resistance management (IRM)
strategy was established for all cotton grown in Israel and is being adjusted on a yearly basis as needed. At present, insect
pest management and IRM strategies are being developed and implemented area-wide for three regions in Israel: Bet She’an Valley,
western Galilee, and western Negev. There are several research groups now working in Israel on various aspects of resistance
including occurrence, mechanisms, and management practices. This paper offers a tentative review of the status of insecticide
and acaricide resistance in pests in Israel. 相似文献
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46.
Blumberg P 《Journal of veterinary medical education》2005,32(3):290-295
Veterinary education as it is frequently implemented creates numerous impediments for the majority of students to achieve self-directed learning. Self-directed learning is a state in which the student is prepared to engage in learning activities defined by him- or herself. Essential components of veterinary education (i.e., curriculum and assessment) inhibit the development of self-directed learning in many ways. This article will make suggestions on how we can promote self-directed learning within traditional veterinary education and discuss how teaching based upon the principles of problem-based learning (PBL) may foster self-directed learning. 相似文献
47.
Hogenkamp A Isohadouten N Reemers SS Romijn RA Hemrika W White MR Tefsen B Vervelde L van Eijk M Veldhuizen EJ Haagsman HP 《Veterinary microbiology》2008,130(1-2):37-46
Many proteins of the calcium-dependent (C-type) lectin family have been shown to play an important role in innate immunity. They can bind to a broad range of carbohydrates, which enables them to interact with ligands present on the surface of micro-organisms. We previously reported the finding of a new putative chicken lectin, which was predominantly localized to the respiratory tract, and thus termed chicken lung lectin (cLL). In order to investigate the biochemical and biophysical properties of cLL, the recombinant protein was expressed, affinity purified and characterized. Recombinant cLL was expressed as four differently sized peptides, which is most likely due to post-translational modification. Crosslinking of the protein led to the formation of two high-molecular weight products, indicating that cLL forms trimeric and possibly even multimeric subunits. cLL was shown to have lectin activity, preferentially binding to alpha-mannose in a calcium-dependent manner. Furthermore, cLL was shown to inhibit the haemagglutination-activity of human isolates of influenza A virus, subtype H3N2 and H1N1. These result show that cLL is a true C-type lectin with a very distinct sugar specificity, and that this chicken lectin could play an important role in innate immunity. 相似文献
48.
Context
East African ecosystems are characterized by the migrations of large herbivores that are highly vulnerable to the recent development of anthropogenic land use change.Objectives
We analyzed land cover changes in the Kenyan-Tanzanian borderlands of the greater Amboseli ecosystem to evaluate landscape connectivity using African elephants as an indicator species.Methods
We used multi-temporal Landsat imagery and a post classification approach to monitor land cover changes over a 43-year period. GIS based methods were accompanied by a literature review for spatial data on land cover changes and elephant migrations.Results
Land cover changed considerably between 1975 and 2017. Wood- and bushlands declined by 16.3% while open grasslands increased throughout the study region (+?10.3%). Agricultural expansion was observed (+?12.2%) occupying important wildlife habitats and narrowing migration corridors. This development has led to the isolation of Nairobi National Park which was previously part of a large contiguous ecosystem. Eight migration corridors were identified of which only one is formally protected. Two others are almost completely blocked by agriculture and three are expected to become endangered under continuing land use changes.Conclusions
Landscape connectivity is still viable for this ecosystem (except for Nairobi National Park). However, the current situation is very fragile as anthropogenic land use changes are threatening most of the identified large mammal migration corridors. Sustainable land use planning with regard to important wildlife habitats and connecting corridors is a crucial task for further conservation work to safeguard a viable future for wildlife populations in the Kenyan-Tanzanian borderlands.49.
M. Candolfi F. Bigler P. Campbell U. Heimbach R. Schmuck G. Angeli F. Bakker K. Brown G. Carli A. Dinter D. Forti R. Forster A. Gathmann S. Hassan M. Mead-Briggs M. Melandri P. Neumann E. Pasqualini W. Powell J. -N. Reboulet K. Romijn B. Sechser Th. Thieme A. Ufer Ch. Vergnet H. Vogt 《Journal of pest science》2000,73(6):141-147
This paper is a guidance document for side-effect testing with plant protection products on non-target arthropods under semi-field and field conditions. The principles, methods, endpoints and interpretation of non-target arthropod semi-field and field trials which should be conducted for registration of plant protection products in the European Union are presented and discussed. The recommendations presented reflect the opinions of the experts from authority, academia, industry and consulting which participated at the IOBC (International Organisation of Biological Control), BART (Beneficial Arthropod Regulatory Testing) group and EPPO (European Plant Protection Organisation) Joint Initiative workshop held in Versailles (France) on the 25–26 October, 1999. 相似文献
50.
Catharina P. Williams 《Asia Pacific viewpoint》2008,49(3):344-353
Drawing on an analysis of in‐depth interviews with returned migrant women from East Nusa Tenggara, Indonesia, this paper considers the links between migration, religious beliefs and subjectivity. Low‐skilled migrant women, including domestic workers, have often been represented as marginalised. This paper argues that in the context of migration, women constantly move through trajectories of power using religion as a spiritual resource. Against the commonly patriarchal characteristics of their religion and community, the women employ cognitive strategies to face challenges in migration. In each stage of their transnational migration, the women's experiences reveal the multitude of ways in which they continue to invest in their beliefs through everyday practices, rituals and networking. These experiences highlight the women's strategies in accessing different forms of power. This study demonstrates the significance of focusing on these women's experiences, including their everyday religious practices and their shifting sense of self, as a way of broadening the conceptual basis of our understanding of female migration. 相似文献