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Aims Rhododendron ponticum L. is reputed to be a post Plio‐Pleistocene relict plant species with a disjunct distribution that comprises the Iberian Peninsula to the west and the Euxinian region plus some restricted Mediterranean areas to the east. We analysed the ecological range (of subsp. baeticum) in the western area (Aljibe Mountains, north of the Strait of Gibraltar) to understand the factors determining the present area limitation. Location Sierra del Aljibe, north of the Strait of Gibraltar (Iberian Peninsula). Methods We selected 20 riparian sites where R. ponticum is common, and compiled data on the ecological diversity of associated woody species and ferns. We established a 500‐m main transect in each site, along the stream or river course, in which we placed five 20‐m‐long plots at regular intervals. We recorded physiographic habitat features, woody plants and fern abundance, and the number of R. ponticum individuals. Results Rhododendron ponticum in southern Spain is restricted to riparian forests in acidic soils (pH 4.0–6.4), and is mainly found on the banks of inclined and enclosed streams. In our inventory we recorded 59 woody taxa and 12 ferns, with R. ponticum being the dominant species of the understorey (mean abundance 78.6%). The communities are characterized by a high incidence of the humid warm temperate element, both in number of species (18.8 ± 3.7 per site) and abundance; meanwhile, the presence of the modern Mediterranean element (mean number of species 3.4 ± 3.8 per site) appears to be favoured by disturbance. These ecological–historical groups of taxa also show distinct patterns of typological habit, frequency of endemism, infrageneric diversity and geographical range. Populations of R. ponticum are characterized by a very variable density of seedlings in many sites, and the virtual lack of juveniles. Main conclusions Riparian forests of the Aljibe Mountains constitute a refuge for R. ponticum where the species persists, but populations appear to be in decline. The narrow ecological range of R. ponticum in the area strongly contrasts with its wide amplitude in the eastern natural area, mainly the Euxinian region, where R. ponticum probably finds better conditions due to the environmental heterogeneity of the region, and the lack of a hot dry season. 相似文献
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A new technique for the treatment of palpebral bags 总被引:13,自引:0,他引:13
A new technique for the treatment of palpebral bags is presented. The technique consists of returning fat to the orbital cavity and retaining it by means of a continuous suture (with nonabsorbable filament) of the capsulopalpebral fascia to the periosteum of the lower orbital rim. The anatomic basis for the technique, after examination of the relevant literature and dissection on fresh cadavers, is analyzed. The procedure followed and results obtained are described in detail. Evaluation of the results suggests to the authors that this might be the method to be applied in the majority of patients. 相似文献
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Cloning and molecular characterization of two genes encoding adhesion proteins involved in Trichomonas vaginalis cytoadherence 总被引:11,自引:2,他引:9
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目的:观察气管内全身麻醉下行全髋置换术患者,术中静脉应用不同剂量右美托咪定对术后芬太尼静脉自控镇痛效果的影响及相关不良反应发生的情况。方法:选择择期在气管内全麻下行全髋置换术的患者60 例,ASA Ⅰ ~Ⅱ级,年龄47~78 岁,体重42~79 kg。患者随机分组法分为3 组(n=20):C 组(盐水对照组)、D1 组(右美托咪定0.5 μg/kg 组)和D2 组(右美托咪定1 μg/kg组),在手术结束前约1 小时按分组分别给予生理盐水和右美托咪啶,术后镇痛使用芬太尼静脉自控镇痛24 h。记录患者术后2h、2~6 h、6~12 h、12~24 h芬太尼的用量;VAS 评分法评估患者术前、术后2 h、6 h、12 h、24 h 时的疼痛程度;记录镇痛期间恶心呕吐、皮肤瘙痒及过度镇静等不良反应发生的情况。结果:术后2h 和术后2~6 h芬太尼用量D1组和D2 组较C 组减少(P<0.05),但D1组和D2 组之间比较无差异(P>0.05);而术后6~12 和12~24 h三组患者芬太尼用量无差异(P>0.05)。术后2 h、2~6 hVAS评分D1 组和D2 组较C组减少(P<0.05),而D1组和D2 组之间比较无差异(P>0.05);术后6~12、12~24 h三组患者VAS 评分无差异(P>0.05)。与C 组比较,D1 组和D2 组镇痛期间恶心呕吐发生率降低(P<0.05),余不良反应各组之间比较无差异(P>0.05)。结论:气管内全身麻醉下行全髋置换术的患者,术中静脉应用右美托咪啶可在术后6 h内增强芬太尼镇痛的效果减少芬太尼的用量,但增大剂量效果并不增加而作用时间也不延长。 相似文献
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David Gonzlez del Portillo Beatriz Arroyo Guillermo García Simn Manuel B. Morales 《Ecology and evolution》2021,11(7):3219
Agriculture intensification threatens farmland bird populations because, among other reasons, it reduces the availability of food resources required to rear their offspring. In our study, we sampled and analyzed total arthropod abundance, biomass and richness, and orthopteran and coleopteran abundance and biomass in different agricultural habitats (alfalfa fields, stubble fields, grazed fields, and field margins) across 4 study localities with different levels of agriculture abandonment–intensification, comparing between areas used and not used by one of the most threatened farmland birds in Europe, the little bustard (Tetrax tetrax), during the chick‐rearing season. Field margins were the taxonomically richest habitat, while alfalfa fields presented significantly higher total arthropod abundance and biomass than other habitats. All arthropod variables were the highest in the localities with clear conservation‐focused agrarian management, and the lowest in the most intensive one. Areas used by little bustards had higher orthopteran and coleopteran abundance and biomass than nonused areas, except for coleopteran biomass in grazed fields. These results highlight the relevance of these arthropods for the species, the importance of dry alfalfa fields as food reservoirs in this critical time of year, the food scarcity in sites where agrarian management disregards farmland bird conservation, and the role of stubbles as providers of food resources during the chick‐rearing season in areas used by the species. The adequate management of alfalfa fields and stubbles to provide those key resources seems crucial to improve little bustard breeding success. 相似文献
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Juan Carlos Senar José Carrillo‐Ortiz Lluïsa Arroyo 《Journal of Field Ornithology》2012,83(2):180-185
ABSTRACT Most parakeets, parrots, and cockatoos are difficult to mark because of their strong beaks and ability to manipulate items with their feet. We developed a marking method that consists of a numbered tag hung on a neck collar. We used this method to successfully monitor Monk Parakeets (Myiopsitta monachus) and Ring‐necked Parakeets (Psittacula krameri) in Barcelona, Spain, from 2003 to 2009. We marked 881 Monk Parakeets and 88 Ring‐necked Parakeets with collars. Fifteen tags placed on adult Monk Parakeets in 2003 (N= 57) lasted until 2008 and nine until 2009. Three of 12 Ring‐necked Parakeets marked in 2003 were resighted in 2008. We estimated that 4.5% of Monk Parakeets and 5.8% of Ring‐necked Parakeets lost their tags, with median intervals between attachment and tag loss of 347 and 370 d, respectively. Behavioral observations revealed no differences in the time budgets of marked and unmarked Monk Parakeets. In addition, the mass of marked Monk Parakeets did not change between successive recaptures. These results suggest that neck collars had no adverse effects on the birds. Neck collars may also be a suitable marking method for other psittacines, with stronger, more durable components likely needed for larger species. 相似文献