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1. Eucalyptus globulus, a tree species planted worldwide in many riparian zones, has been reported to affect benthic macroinvertebrates negatively. Although there is no consensus about the effects of Eucalyptus on aquatic macrobenthos, its removal is sometimes proposed as a means of ecological restoration. 2. We combined the sampling of macroinvertebrates with measurement of the colonisation of leaf packs in mesh bags, to examine the effects of riparian Eucalyptus and its litter on benthic macroinvertebrates in three small streams in California, U.S.A. Each stream included one reach bordered by Eucalyptus (E‐site) and a second bordered by native vegetation (N‐site). 3. The macrobenthos was sampled and two sets of litter bags were deployed at each site: one set with Eucalyptus litter (Euc‐bags) and one with mixed native tree litter (Nat‐bags) containing Quercus, Umbellularia, Acer and Alnus. Bags were exposed for 28, 56 and 90 days and this experiment was repeated in the autumn, winter and spring to account for effects of changing stream flow and insect phenology. 4. Litter input (average dry mass: 950 g m?2 year?1 in E‐sites versus 669 g m?2 year?1 in N‐sites) was similar, although in‐stream litter composition differed between E‐ and N‐sites. Litter broke down at similar rates in Euc‐bags and Nat‐bags (0.0193 day?1 versus 0.0134 day?1), perhaps reflecting the refractory nature of some of the leaves of the native trees (Quercus agrifolia). 5. Summary metrics for macroinvertebrates (taxon richness, Shannon diversity, pollution tolerance index) did not differ significantly between the E and N sites, or between Euc‐bags and Nat‐bags. No effect of exposure time or site was detected by ordination of the taxa sampled. However, distinct seasonal ordination clusters were observed in winter, spring and autumn, and one of the three streams formed a separate cluster. 6. The presence of Eucalyptus was less important in explaining the taxonomic composition of the macrobenthos than either ‘season’ or ‘stream’. Similarly, these same two factors (but not litter species) also helped explain the variation in leaf breakdown. We conclude that patches of riparian Eucalyptus and its litter have little effect on stream macrobenthos in this region. 相似文献
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MANUEL B. CRESPO ANTONIO DE LA TORRE JOSE L. SOLANAS 《Botanical journal of the Linnean Society. Linnean Society of London》1994,116(2):135-144
Linaria arabiniana sp. nov. is described from coastal sand dunes of a very reduced area in Alicante Province (south-eastern part of the Iberian Peninsula). It is a perennial herb characterized by its 3–4-verticillate leaves, glabrous stems, large violet or rarely yellow flowers, and bicoloured usually flat seeds. Morphological characteristics and taxonomic affinities of this taxon are discussed, as are data on its ecology, phytosociology, and eventual conservation features. 相似文献
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Hofstede Stefanie N Marang-van de Mheen Perla J Wentink Manon M Stiggelbout Anne M Vleggeert-Lankamp Carmen LA Vliet Vlieland Thea PM van Bodegom-Vos Leti 《Implementation science : IS》2013,8(1):1-11
Background
Venous thromboembolism (VTE) is a common preventable cause of mortality in hospitalized medical patients. Despite rigorous randomized trials generating strong recommendations for anticoagulant use to prevent VTE, nearly 40% of medical patients receive inappropriate thromboprophylaxis. Knowledge-translation strategies are needed to bridge this gap.Methods
We conducted a 16-week pilot cluster randomized controlled trial (RCT) to determine the proportion of medical patients that were appropriately managed for thromboprophylaxis (according to the American College of Chest Physician guidelines) within 24 hours of admission, through the use of a multicomponent knowledge-translation intervention. Our primary goal was to determine the feasibility of conducting this study on a larger scale. The intervention comprised clinician education, a paper-based VTE risk assessment algorithm, printed physicians’ orders, and audit and feedback sessions. Medical wards at six hospitals (representing clusters) in Ontario, Canada were included; three were randomized to the multicomponent intervention and three to usual care (i.e., no active strategies for thromboprophylaxis in place). Blinding was not used.Results
A total of 2,611 patients (1,154 in the intervention and 1,457 in the control group) were eligible and included in the analysis. This multicomponent intervention did not lead to a significant difference in appropriate VTE prophylaxis rates between intervention and control hospitals (appropriate management rate odds ratio = 0.80; 95% confidence interval: 0.50, 1.28; p = 0.36; intra-class correlation coefficient: 0.022), and thus was not considered feasible. Major barriers to effective knowledge translation were poor attendance by clinical staff at education and feedback sessions, difficulty locating preprinted orders, and lack of involvement by clinical and administrative leaders. We identified several factors that may increase uptake of a VTE prophylaxis strategy, including local champions, support from clinical and administrative leaders, mandatory use, and a simple, clinically relevant risk assessment tool.Conclusions
Hospitals allocated to our multicomponent intervention did not have a higher rate of medical inpatients appropriately managed for thromboprophylaxis than did hospitals that were not allocated to this strategy. 相似文献100.
Comparison of Single and Touchdown PCR Protocols for Detecting Pneumocystis jirovecii DNA in Paraffin-Embedded Lung Tissue Samples 总被引:1,自引:0,他引:1