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171.
AIMS: To determine the irradiation dose necessary to reduce the populations of Bacillus anthracis spores in a dry medium in postal envelopes. METHODS AND RESULTS: Bacillus anthracis Sterne 34F2 spores were dispersed in non-fat dry milk and then placed into standard business postal envelopes. The spores were treated with a sequence of irradiation doses to determine the decimal reduction value (D10) in kiloGrays (kGy). The average D10 value was 3.35 +/- 0.02 kGy. CONCLUSIONS: An irradiation dose of 40.2 kGy would be required to result in a process equivalent to the thermal canning process (12 D10 reduction) to eliminate Clostridium botulinum spores. SIGNIFICANCE AND IMPACT OF THE STUDY: Irradiation is an effective means of reducing or eliminating B. anthracis spores in a dry medium in postal envelopes. 相似文献
172.
This paper reports an analysis of a typical case of negative bilateral externality – a situation in which two legitimate activities, fishing and wildlife conservation, each give rise to damages to the other party. The Cornish fishing industry believes that its annual profits are reduced by an estimated £100 000 because of the damage by seal populations to caught fish. About 80 individuals belonging to the Cornish Grey Seal population (of about 400 specimens) are killed as a by-catch of trawling. Thus, the status quo is clearly inefficient: seals are perceived to damage fish and fishermen definitely damage seals. The biological dynamics of the seal population is not absolutely clear, so that a precautionary approach requires that care should be taken to avoid the risk of damaging the population in an irreversible way. Moreover, public opinion considers seals to be a high value flagship species. One of the goals of any conflict resolution should be to capture the economic value of seal conservation – i.e. to convert conservation benefits into resource flows – and use at least part of it in order to create incentives for a more efficient allocation of resources. The authorities should invest in seal conservation (i.e. compensating fishermen) if the benefits deriving from conservation exceed the opportunity costs of conservation. Such a solution clearly requires that the conservation benefits be estimated. To investigate the economic value of seal conservation a contingent valuation study is carried out. A contingent valuation study utilises a questionnaire approach and part of the questionnaire seeks to elicit individuals' willingness to pay (WTP) for a change in the state of some good or asset, in this case seal conservation. Due to resource limitations, the sample size of those interviewed in the study reported is small, so that we cannot be extremely confident about the results. However, they are consistent with those derived from similar studies on flagship species. Results show a mean WTP for recreational use of seals of about £8 per person for the option of seeing seals in a specialised sanctuary for seals recovered from accidents, and closer to £9 for seeing seals in the wild. The annual non-use value of seals – i.e. value unassociated with actual viewing – was found to be £526 000 in the most conservative estimation, aggregated over the Seal Sanctuary visitors. This economic potential could be realised in several ways and used to compensate fishermen for changing fishing techniques, targets and fishing areas. Finally, we investigate the role the Seal Sanctuary is playing in this context and some policy suggestions are discussed. 相似文献
173.
174.
Joseph H. Manson 《Human nature (Hawthorne, N.Y.)》1998,9(2):97-117
The human “environment of evolutionary adaptedness” can only be inferred indirectly. In contrast, the behavior of some nonhuman
animals can be compared among “natural” and various altered environments. As an example, male immigration tactics in unprovisioned
versus provisioned macaque (Macaca) populations are compared using Tooby and Cosmides’s (1992) framework for evolutionary functional analysis. In unprovisioned
populations, social groups contain few males, and immigrant male takeovers of alpha rank occur frequently. In provisioned
populations, groups contain many males, and males almost invariably enter social groups at very low rank and rise in rank
only as more dominant males emigrate or die. Male conformity to the “seniority rule” is hypothesized to represent the behavioral
output of an evolved decision-making algorithm (psychological mechanism) that takes into account (1) the net payoff of each
rank in the dominance hierarchy and (2) the power of male group size as a predictor of the likelihood of successful immigrant
takeover.
Joseph H. Manson is Assistant Professor of Anthropology at the University of California, Los Angeles. His research interests
are social relationships in nonhuman primates and humans, with particular emphases on mate choice, courtship tactics, intrasexual
competition, and (currently) mother-infant relationships and infant handling. He has conducted fieldwork on rhesus macaques
at Cayo Santiago and white-faced capuchins in Costa Rica. 相似文献
175.
姑婆山紧邻南岭生物多样性保护优先区,孕育了丰富的生物资源。为了解该区域大型真菌物种多样性,该文采用随机踏查法对广西姑婆山自治区级自然保护区(以下简称姑婆山)及邻近地区大型真菌资源进行调查采集,并结合形态学和分子生物学方法进行物种鉴定。结果表明:(1)共发现348种大型真菌,隶属于2门6纲17目69科175属,其中包含食用菌40种、药用菌42种、毒菌7种。(2)对该区的物种组成分析表明,优势科为蘑菇科(Agaricaceae)、牛肝菌科(Boletaceae)、粉褶蕈科(Entolomataceae)和锈革菌科(Hymenochaetaceae)等9科;优势属为鹅膏属(Amanita)、靴耳属(Crepidotus)、毛皮伞属(Crinipellis)和粉褶蕈属(Entoloma)等11属。(3)共发现2个中国特有属,即脆孔菌属(Fragiliporia)和臧氏牛肝菌属(Zangia);11个中国特有种,即厚集毛菌(Coltricia crassa)、魏氏集毛菌(C.weii)、丛生粉褶蕈(Entoloma caespitosum)、极细粉褶蕈(E.praegracile)、近薄囊粉褶蕈... 相似文献
176.
R. Gary Chiang Jennifer A. Chiang 《Archives of insect biochemistry and physiology》2010,74(2):103-113
The blood‐feeding insect, Rhodnius prolixus, has been raised in the laboratory for close to 100 years. Various feeding techniques have been employed ranging from the use of warm‐blooded hosts, to the use of previously collected blood offered through artificial membranes. This study compared the fecundity in mated and unmated females fed rabbit blood directly from the shaved belly of a rabbit to that of females fed defibrinated rabbit blood through an artificial membrane. These results confirm previous reports that this insect's feeding efficacy is reduced using an artificial membrane. It also demonstrates for the first time that the fecundity index, which measures the efficiency of turning the blood meal into eggs, is significantly reduced. We suggest that the natural feeding on a warm‐blooded host may provide cues that have the short‐term effect of enhancing the act of feeding and the long‐term effect of increasing egg production efficiency. Until an artificial feeding method that does not interfere with feeding and fecundity is devised, experiments on reproduction in R. prolixus warrant the use of a warm‐blooded host to emulate feeding in its natural setting. © 2010 Wiley Periodicals, Inc. 相似文献
177.
The Grassland Biome is currently one of the most threatened biomes in South Africa and is in dire need of a biomonitoring protocol. The components of ecological integrity in these ecosystems are, however, too diverse and time-consuming to measure scrupulously. It is therefore necessary to develop a set of grassland indicators that are efficient and rapid in their assessment of grassland ecosystem integrity. The South African Grassland Scoring System (SAGraSS), based on the grassland insect community, is such a suggested indicator. The present study is the first to investigate the applicability and rapidity of this proposed method. Although SAGraSS scores correlated significantly with Ecological Index values (the most commonly used index by which veld condition is evaluated in central South Africa), the method proved to be tedious and the identification of insects taxing. We offer a number of changes to make the SAGraSS method a more rapid method of assessment. 相似文献
178.
Abstract 1. Patch time allocation has been mostly studied in female parasitoids exploiting patches of hosts. Different parameters such as oviposition, host encounters, patch quality, etc. have been repeatedly shown to modify the time females invest on hosts. 2. Male parasitoids are expected to maximise their lifetime fitness by maximising the number of females inseminated during their life. Because they can be sperm and/or time limited, they should optimise their time allocation on emergence patches. 3. Patch time allocation thus appears to be an important question for both male and female parasitoids. 4. In this study, we determined the parameters used by males of the egg parasitoid Trichogramma turkestanica to decide when to leave the emergence patch. Among the different patch‐leaving parameters tested, only contacts with parasitised hosts and presence of virgin females significantly influenced the patch‐leaving tendency. 5. Our results suggest that males express behaviours that could enable them to optimise their patch exploitation time, as females do, but using different strategies. 相似文献
179.
目的:探讨目标教学法在护理教学查房中的临床应用价值,以培养护生的临床思维能力,并且提高实践工作能力。方法:选取我院2014年5月~2014年9月在急诊科实习的护生120人为研究对象,在实习之初,按照随机的原则将其分为观察组与对照组,每组60人。在查房中,观察组实施目标教学法,对照组实施常规护理教学法。实习结束后,调查两组护生对查房时教学与课堂效果的满意程度,记录两组护生病历书写的质量以及在实习结束后,通过考核,统计两组护生的在理论成绩、基础护理成绩、专科护理成绩以及护理综合技能方面的成绩,然后对所得到的数据进行统计,以探讨目标教学法在护理教学查房中的临床应用价值。结果:从查房时教学的满意程度及对课堂效果的满意程度来看,观察组都高于对照组,差异具有统计学意义(P0.05);观察组病历书写优良的人数为48,优良率为80%,高于对照组,差异具有统计学意义(P0.05);观察组护生的理论成绩、基础护理成绩、专科护理成绩及护理综合技能的成绩均高于对照组,差异具有统计学意义(P0.05)。结论:目标教学法是一种科学、合理并且适合时代发展要求的新型教学法,应用于护理教学查房中,能提高护生的主动性,激发护生的学习兴趣,充分发掘其潜能,做到理论与实际的结合,从而提高学习者的自身能力,值得临床推广应用。 相似文献
180.
目的:探讨不同类型心力衰竭患者心电图QRS 波时限与血浆N末端B型利钠肽原(NT-proBNP)水平之间的关系及其临床
意义。方法:选择我院2012 年7 月至2014 年6 月接收的慢性心力衰竭患者300 例,作为研究组,将患者分为收缩性心力衰竭组
(S组)和舒张性心力衰竭组(D组);另外,选取我院非CHF 患者132 例,作为对照组。测定所有受试者的心电图QRS 波时限,及
血浆中NT-proBNP 水平,分析血浆NT-proBNP 水平与QRS 波时限及NYHA心功能分级关系。结果:与对照组相比,研究组QRS
波时限均延长,血浆NT-proBNP水平显著升高(P<0.05),其中S 组比D 组明显延长,且S 组血浆NT-proBNP水平高于D 组
(P<0.05)。三组NYHA 分级对比发现,差异均具有统计学意义(P<0.05);S 组患者血浆NT-proBNP水平与QRS 波时限及NYHA
心功能分级之间呈正相关;D 组患者血浆NT-proBNP水平与QRS 波时限及NYHA心功能分级之间无明显的相关性。结论:临床
上可以将NT-proBNP水平和QRS 波时限结合起来诊断慢性心力衰竭患者的类型,以便于之后的治疗。 相似文献