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771.
Editor's note: This Conservation Forum begins with a reprinted editorial by Elizabeth Bennett from the August 2000 issue of Conservation Biology . Several papers were submitted in repsonse to that piece, and it is reprinted here to start this forum.  相似文献   
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ABSTRACT: This study evaluated the use of a modified pebble count procedure (Bevenger and King, 1995) to detect cumulative watershed effects on headwater streams in the Routt National Forest in northcentral Colorado. The 42 sample reaches were stratified by disturbance (reference or disturbed) and geologic terrene (granitic or mixed sedimentary-volcanic). Water surface slope was a significant control on the number of fine particles in the reference reaches in both terranes, and the data from the disturbed reaches were adjusted accordingly. The disturbed reaches in the granitic terrene generally had a higher percentage of fine particles, and the adjusted number of fine particles was significantly correlated with the number of road crossings. Disturbed reaches in the sedimentary-volcanic (s-v) terrane generally did not have significantly more fine particles, nor were the adjusted numbers of fine particles significantly correlated with any management index. The lack of significant trends in the s-v streams is probably due to differences in weathering between the two rock types, and the location of the sample reach relative to sedimentary outcrops. Two other procedures were also used to assess cumulative watershed effects, with the Pfankuch channel stability rating yielding stronger and more consistent differences between the reference and the disturbed streams than the Tarzwell substrate ratio. We conclude that it may be difficult to define a standard reference condition, and that the number of road crossings is more strongly correlated with the number of fine particles than equivalent clearcut area.  相似文献   
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The hepatitis E virus (HEV) is the causative agent of Hepatitis E, an enterically transmitted disease. HEV infections in pigs and humans have been reported worldwide, but data from Mexico are scarce. In the present study, the prevalence of anti-HEV IgG antibodies was investigated in a quite large number of swine from Mexico by means of an ELISA based on a recombinant open reading frame 2 protein of HEV genotype 3. Serum samples from 683 healthy pigs (1–48 months old), collected during 2010–2013 in 109 herds from 48 municipalities located in 9 states in the centre of the country were assayed. A 30.75 % (210/683) of the sera tested were positive, and they were distributed along all the states included in the study. The prevalence of anti-HEV antibodies varied widely between municipalities and herds, and it was higher in pigs 4–6 months of age. No relationships were detected between seroprevalences and farm characteristics. Forty individual faecal samples were analysed by RT-PCR and all resulted negative. These data indicate that HEV infection is widespread in Mexican pigs; thus, representing a potential zoonotic risk for humans.  相似文献   
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The requirement for novel decontamination technologies for use in hospitals is ever present. One such system uses 405 nm visible light to inactivate microorganisms via ROS-generated oxidative damage. Although effective for bacterial and fungal inactivation, little is known about the virucidal effects of 405 nm light. Norovirus (NoV) gastroenteritis outbreaks often occur in the clinical setting, and this study was designed to investigate potential inactivation effects of 405 nm light on the NoV surrogate, feline calicivirus (FCV). FCV was exposed to 405 nm light whilst suspended in minimal and organically-rich media to establish the virucidal efficacy and the effect biologically-relevant material may play in viral susceptibility. Antiviral activity was successfully demonstrated with a 4 Log10 (99.99%) reduction in infectivity when suspended in minimal media evident after a dose of 2.8 kJ cm?2. FCV exposed in artificial faeces, artificial saliva, blood plasma and other organically rich media exhibited an equivalent level of inactivation using between 50–85% less dose of the light, indicating enhanced inactivation when the virus is present in organically-rich biologically-relevant media. Further research in this area could aid in the development of 405 nm light technology for effective NoV decontamination within the hospital environment.  相似文献   
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Are trade-offs in plant resprouting manifested in community seed banks?   总被引:2,自引:0,他引:2  
Clarke PJ  Dorji K 《Ecology》2008,89(7):1850-1858
Trade-offs in allocation to resprouting vs. seedling regeneration in plants are predicted to occur along fire disturbance gradients. Increased resprouting ability should be generally favored in plant communities with a high probability of crown fire return. Hence, communities dominated by resprouters are predicted to have smaller seed banks than those dominated by species killed by fire. We tested whether there were trait shifts in resprouting ability among growth forms (short-lived herbaceous vs. ground-dwelling perennials vs. shrubs) and among communities (rocky outcrop vs. sclerophyll forest) with contrasting probabilities of crown fire return. Resprouting was more common in ground-dwelling perennials and in the sclerophyll forest community with a high probability of crown fire. Soil seed banks were sampled in rocky outcrop and sclerophyll forest communities in recently burned (18 months) and long-since-burned (12 years) locations at interspersed replicated sites. Collected seed banks were treated with orthogonal treatments of fire stimuli or no stimuli, and seedling emergence was measured in controlled conditions. Seed bank composition reflected the pattern of extant vegetation, with resprouting species being more common in the community with a higher probability of crown fire. Overall, however, resprouting species were poorly represented in the seed bank compared to those species killed by fire. Predicted shifts in allocation to seed production were strongly manifested in community seed banks across the disturbance gradient. Fewer species, seedlings, and seedlings per adult emerged from seed banks in the sclerophyll forest. This suggests that the dominance of resprouting species influences recruitment at the community scale. Community patterns in the seed bank also reflected predicted trade-offs with plant size and growth rate. Short-lived species that are killed by fire dominated the seed bank on rocky outcrops, while longer-lived resprouting species were found in low abundance. Life history trade-offs in persistence and regeneration strongly contribute to coexistence patterns between and within communities with contrasting probabilities of fire return.  相似文献   
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Partnerships between organisations in humanitarian crisis situations generally are challenging, but at the apex are those established as part of remote management in a context of extreme insecurity. To date, little systematic research has been conducted on arrangements between local organisations that have access to crisis‐affected populations and international organisations that hold the purse strings. This paper presents the findings of nine months of qualitative research conducted with five Syrian local organisations and their international partners engaging in humanitarian action across the Turkey–Syria border, and presents insights into the components of successful partnerships. It redefines capacity along organisational and operational lines, and unpacks how monitoring and evaluation and donor requirements create tension and, at times, place local organisations at risk. The paper highlights the centrality of trust in successful partnerships, and describes the personalisation of the conflict by local organisations. Based on a historical case study of civil society in northern Iraq, it closes with some suggestions for long‐term sustainability.  相似文献   
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