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排序方式: 共有1166条查询结果,搜索用时 31 毫秒
991.
Kevin J. Gaston Kevin Charman Paul R. Armsworth Robert A. Briers Roger Catchpole William E. Kunin Paul Opdam David A. Stroud 《Biological conservation》2006,132(1):76-87
Given the importance placed on protected areas, determining their effectiveness in representing and maintaining biodiversity is a core issue in conservation biology. Nonetheless, frameworks identifying the breadth of issues associated with this effectiveness, and case studies of how well these are understood in particular regions, remain lacking. In this paper, we provide such a framework and an overview of the current state of knowledge of the ecological effectiveness of protected areas in the United Kingdom. Arguably, better data are available to address such issues in this region than anywhere else in the world. Nonetheless, studies remain scarce and have focussed foremost on the, rather narrow, issue of the effectiveness of management actions on individual sites in order to deliver fixed conservation objectives and discharge statutory responsibilities. Some attention has also been paid to how well the regional collection or portfolio of protected areas performs, particularly in capturing biodiversity features. Work on the extent to which protected areas in the United Kingdom form effective functional networks is in its infancy, but initiatives are under development. We identify some of the questions about the effectiveness of protected areas to which answers need to be known at the site, portfolio and network levels, and how significant progress might be achieved in addressing these. 相似文献
992.
中国大多数桉树资源主要集中在较为温暖的沿海地区.目前在湖南和江西等华南和中南省份较为冷凉的内陆地区,通过选择一些合适的耐寒桉树品种,种植了一些规模不大的桉树人工示范林,这些示范林显示出了较好的适应性与丰产性.这些较为冷凉的内陆地区有着立地条件较为优越的适合人工林发展的广大林地.对于较冷地区,尤其是湖南省来说,通过分析所... 相似文献
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995.
Hughes R 《Public health nutrition》2007,10(4):324-325
996.
Further assessment of houseflies (Musca domestica) as vectors for the mechanical transport and transmission of porcine reproductive and respiratory syndrome virus under field conditions 总被引:1,自引:0,他引:1
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Andrea Pitkin John Deen Satoshi Otake Roger Moon Scott Dee 《Canadian journal of veterinary research》2009,73(2):91-96
The purpose of this study was to evaluate the potential for houseflies (Musca domestica) to mechanically transport and transmit porcine reproductive and respiratory syndrome virus (PRRSV) between pig populations under controlled field conditions. The study employed swine housed in commercial livestock facilities and a release-recapture protocol involving marked (ochre-eyed) houseflies. To assess whether transport of PRRSV by insects occurred, ochre-eyed houseflies were released and collected from a facility housing an experimentally PRRSV-inoculated population of pigs (facility A) and collected from a neighboring facility located 120 m to the northwest that housed a naïve pig population (facility B). All samples were tested for PRRSV RNA by polymerase chain reaction (PCR). To assess transmission between the 2 populations, blood samples were collected from naïve pigs in facility B at designated intervals and tested by PCR. A total of 7 replicates were conducted. During 2 of 7 replicates (1 and 5), PCR-positive ochre-eyed houseflies were recovered in facility B and pigs in this facility became infected with PRRSV. Chi-squared analysis indicated that the presence of PRRSV in an insect sample was significantly (P = 0.0004) associated with infection of facility B pigs. Porcine reproductive and respiratory syndrome virus was not recovered from other reported routes of transmission during the study period, including air, fomites, and personnel. In conclusion, while an insufficient number of replicates were conducted to predict the frequency of the event, houseflies may pose some level of risk for the transport and transmission of PRRSV between pig populations under field conditions. 相似文献
997.
Hiroaki Kamishina Jennifer A. Cheeseman Roger M. Clemmons 《Veterinary research communications》2009,33(7):645-657
The present in vitro study was designed to evaluate whether canine bone marrow stromal cells (BMSCs) promote neurite outgrowth from dorsal root
ganglion (DRG) neurons. Bone marrow aspirates were collected from iliac crests of three young adult dogs. DRG neurons were
cultured on BMSCs, fibroblasts, or laminin substrates. DRG neurons were also cultured in BMSC- or fibroblast-conditioned media.
DRG neurons grown on BMSCs extended longer neurites and developed a much more elaborate conformation of branching neurites
compared to those on fibroblasts or laminin. Quantitative analysis revealed that these effects were associated with the emergence
of increased numbers of primary and branching neurites. The effect appears to be dependent upon cell-cell interactions rather
than by elaboration of diffusible molecules. With more extensive investigations into the basic biology of canine BMSCs, their
ability for promoting neurite outgrowth may be translated into a novel therapeutic strategy for dogs with a variety of neurological
disorders. 相似文献
998.
Saeed Ataei Richard Burchmore J. Christopher Hodgson Anna Finucane Roger Parton John G. Coote 《Research in veterinary science》2009,87(2):207-210
Pasteurella multocida serotype B:2 is the causative agent of haemorrhagic septicaemia (HS), a fatal disease of cattle and buffaloes. As a step towards the identification of individual antigens that may protect against HS, proteins present in a sonicated cell extract (SCE) and outer-membrane protein (OMP) preparation of a wild-type P. multocida serotype B:2 were investigated by immunoblotting with sera from calves which had been protected against challenge with a virulent strain of P. multocida B:2 by vaccination with a live-attenuated aroA derivative of the challenge strain. Five proteins in SCE, of approximately 50, 37, 30, 26 and 16 kDa, were recognised by the sera. In an OMP preparation, two bands, at 37 and 50 kDa, were recognised as strongly immunogenic. Mass spectrometry analysis of proteins corresponding in size to those detected by immunoblotting identified the 37 kDa band as OmpA, but the band at 50 kDa was not identified with certainty. A major 30 kDa OMP, identified as OmpH, was not strongly immunogenic. 相似文献
999.
猪场沙门氏菌控制新标准 总被引:1,自引:0,他引:1
沙门氏菌感染一直是一种令养猪生产者头痛的疾病。自2010年起,欧洲将提高养猪场沙门氏菌控制的标准。因此,欧洲养猪生产者必须意识到并在性价比和安全性上处理好他们所涉及的不断增加的食品安全法律义务。 相似文献
1000.
Parsons DW Li M Zhang X Jones S Leary RJ Lin JC Boca SM Carter H Samayoa J Bettegowda C Gallia GL Jallo GI Binder ZA Nikolsky Y Hartigan J Smith DR Gerhard DS Fults DW VandenBerg S Berger MS Marie SK Shinjo SM Clara C Phillips PC Minturn JE Biegel JA Judkins AR Resnick AC Storm PB Curran T He Y Rasheed BA Friedman HS Keir ST McLendon R Northcott PA Taylor MD Burger PC Riggins GJ Karchin R Parmigiani G Bigner DD Yan H Papadopoulos N Vogelstein B Kinzler KW Velculescu VE 《Science (New York, N.Y.)》2011,331(6016):435-439
Medulloblastoma (MB) is the most common malignant brain tumor of children. To identify the genetic alterations in this tumor type, we searched for copy number alterations using high-density microarrays and sequenced all known protein-coding genes and microRNA genes using Sanger sequencing in a set of 22 MBs. We found that, on average, each tumor had 11 gene alterations, fewer by a factor of 5 to 10 than in the adult solid tumors that have been sequenced to date. In addition to alterations in the Hedgehog and Wnt pathways, our analysis led to the discovery of genes not previously known to be altered in MBs. Most notably, inactivating mutations of the histone-lysine N-methyltransferase genes MLL2 or MLL3 were identified in 16% of MB patients. These results demonstrate key differences between the genetic landscapes of adult and childhood cancers, highlight dysregulation of developmental pathways as an important mechanism underlying MBs, and identify a role for a specific type of histone methylation in human tumorigenesis. 相似文献