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排序方式: 共有115条查询结果,搜索用时 15 毫秒
81.
82.
1. European hares Lepus europaeus have declined throughout Europe since the 1960s. Possible reasons for this include agricultural intensification and changes in climate and predator numbers, but no clear consensus has been reached as to the relative importance of each of these. We aimed to identify factors associated with high and low hare numbers throughout Europe, to determine which could have caused population declines. 2. Results of 77 research papers from 12 European countries were summarized. Relationships between hare density and demographics and habitat, climate, hunting and predator variables were examined and quantified where possible. Temporal changes in factors identified as being associated with high or low numbers of hares were then examined to see if they could explain population declines. 3. Data from pastural habitats were limited, but densities of hares were low. Arable habitats had higher densities than mixed areas in spring, unless farming was intensive in which case densities were similar. In autumn the two habitats had similar densities. Field size, temperature, precipitation and hunting had no effect on density throughout Europe. Fecundity was affected by climate. 4. Arable land, various crops, fallow habitat and temperature were positively associated, and monoculture, precipitation and predators negatively associated with hare abundance. The relationship of field size, pasture and woodland with abundance depended on spatial scale. 5. Habitat changes caused by agricultural intensification are the ultimate cause of hare population declines. Effects of changes in climate or predator numbers are magnified by the loss of high-quality year-round forage and cover. Further research is required on how habitat changes affect fecundity and survival, and to identify which parameters have the greatest impact on population numbers. Farmland management policies that target the re-establishment of some of the habitat diversity lost within fields, farms and landscapes will help to reverse the decline of the European hare. 相似文献
83.
Farida F Berkhof Nynke E Doornewaard-ten Hertog Steven M Uil Huib AM Kerstjens Jan WK van den Berg 《Respiratory research》2013,14(1):125
Background
Macrolides reduce exacerbations in patients with COPD. Their effects on health status has not been assessed as primary outcome and is less clear. This study assessed the effects of prophylactic azithromycin on cough-specific health status in COPD-patients with chronic productive cough.Methods
In this randomised controlled trial 84 patients met the eligibility criteria: age of ≥40 years, COPD GOLD stage ≥2 and chronic productive cough. The intervention-group (n = 42) received azithromycin 250 mg 3 times a week and the control-group (n = 42) received a placebo. Primary outcome was cough-specific health status at 12 weeks, measured with the Leicester Cough Questionnaire (LCQ). Secondary outcomes included generic and COPD-specific health status and exacerbations. Changes in adverse events and microbiology were monitored.Results
Mean age of participants was 68 ± 10 years and mean FEV1 was 1.36 ± 0.47 L. The improvement in LCQ total score at 12 weeks was significantly greater with azithromycin (difference 1.3 ± 0.5, 95% CI 0.3;2.3, p = 0.01) and met the minimal clinically important difference. Similar results were found for the domain scores, and COPD-specific and generic health status questionnaires. Other secondary endpoints were non-significant. No imbalances in adverse events were found.Conclusions
Prophylactic azithromycin improved cough-specific health status in COPD-patients with chronic productive cough to a clinically relevant degree.Trial registration
ClinicalTrials.gov NCT01071161相似文献84.
Matteo Morello Valentina R Minciacchi Paola de Candia Julie Yang Edwin Posadas Hyung Kim Duncan Griffiths Neil Bhowmick Leland WK Chung Paolo Gandellini Michael R Freeman Francesca Demichelis Dolores Di Vizio 《Cell cycle (Georgetown, Tex.)》2013,12(22):3526-3536
Prostate cancer cells release atypically large extracellular vesicles (EVs), termed large oncosomes, which may play a role in the tumor microenvironment by transporting bioactive molecules across tissue spaces and through the blood stream. In this study, we applied a novel method for selective isolation of large oncosomes applicable to human platelet-poor plasma, where the presence of caveolin-1-positive large oncosomes identified patients with metastatic disease. This procedure was also used to validate results of a miRNA array performed on heterogeneous populations of EVs isolated from tumorigenic RWPE-2 prostate cells and from isogenic non-tumorigenic RWPE-1 cells. The results showed that distinct classes of miRNAs are expressed at higher levels in EVs derived from the tumorigenic cells in comparison to their non-tumorigenic counterpart. Large oncosomes enhanced migration of cancer-associated fibroblasts (CAFs), an effect that was increased by miR-1227, a miRNA abundant in large oncosomes produced by RWPE-2 cells. Our findings suggest that large oncosomes in the circulation report metastatic disease in patients with prostate cancer, and that this class of EV harbors functional molecules that may play a role in conditioning the tumor microenvironment. 相似文献
85.
CHANGES IN THE INTERNAL CARBOHYDRATES OF BEECH MYCORRHIZAS DURING TREATMENT WITH AZIDE 总被引:2,自引:2,他引:0
D. H. JENNINGS 《The New phytologist》1958,57(2):254-255
86.
J. N. JENNINGS 《The New phytologist》1955,54(2):199-207
87.
Studies on Factors which promote Germination of Raspberry Seeds 总被引:1,自引:0,他引:1
The germination of raspberry seeds was favoured by applyingcertain combinations of chemical pretreatment before givingup to six weeks of moist-chilling before sowing, by adding 500p.p.m. gibberellic acid just before sowing, and by providingsupplementary light after sowmg. The most useful chemical pretreatmentwas 20 minutes with concentrated sulphuric acid followed bysix days with 1.0 per cent calcium hypochlorite containing anexcess of calcium hydroxide. For some seed samples such pretreatmenteliminated the need for a subsequent period of moist-chilling,but for others a six-week period of moist-chilling was stillrequired. Pretreatment with higher concentrations than 1.0 percent of calcium hypochiorite, 0.5 per cent of sodium hypochlorite,or 1.0 per cent of thiourea, or pretreatment with the statedconcentrations of these chemicals but in each case without theaddition of calcium hydroxide, frequently delayed or preventedgermination. The results of these studies are in accord withthe hypothesis that the germination capacity of raspberry seedsis determined by interactions between growth inhibitors andpromoters. Such substances have been detected m blackberry seedsand it is suggested that a similar situation exists in seedsof the raspberry. 相似文献
88.
D. L. JENNINGS 《The Annals of applied biology》1979,93(3):319-326
Useful resistance to Leptosphaeria coniothyrium was found in the red raspberry cv. Latham, but its effectiveness was affected by the stage of growth reached by the canes when they were inoculated and by the kind of inoculum used: it was effective when field-grown canes were inoculated in mid-August but less so when they were inoculated in early July, and more effective against a spore inoculum than against a mycelial one. Resistance was inherited as a dominant multigenic character, but there were interactions between parents and two very favourable combinations were found.
The species Rubus pileatus, R. mesogaeus, R. coreanus and R. lasiocarpus showed resistance when inoculated in pot experiments, but F1 hybrids obtained by crossing them with the raspberry were largely susceptible. The problems of using these resistance sources in breeding are discussed. 相似文献
The species Rubus pileatus, R. mesogaeus, R. coreanus and R. lasiocarpus showed resistance when inoculated in pot experiments, but F
89.
90.
RON EGLASH AUDREY BENNETT CASEY O'DONNELL SYBILLYN JENNINGS MARGARET CINTORINO 《American anthropologist》2006,108(2):347-362
Ethnomathematics is the study of mathematical ideas and practices situated in their cultural context. Culturally Situated Design Tools (CSDTs) are web-based software applications that allow students to create simulations of cultural arts—Native American beadwork, African American cornrow hairstyles, urban graffiti, and so forth—using these underlying mathematical principles. This article is a review of the anthropological issues raised in the CSDT project: negotiating the representations of cultural knowledge during the design process with community members, negotiating pedagogical features with math teachers and their students, and reflecting on the software development itself as a cultural construction. The move from ethnomathematics to ethnocomputing results in an expressive computational medium that affords new opportunities to explore the relationships between youth identity and culture, the cultural construction of mathematics and computing, and the formation of cultural and technological hybridity. 相似文献