124 resultados para Scientific reviews


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In recent decades there has been a marked decline in most ortolan bunting Emberiza hortulana populations in temperate Europe, with many regional populations now extinct or on the brink of extinction. In contrast, Mediterranean and, as far as we know, eastern European popula-tions seem to have remained relatively stable. The causes of decline remain unclear but include: habitat loss and degradation, and related reduction in prey availability; climate change on the breeding grounds; altered population dynamics; illegal captures during migration; and environmental change in wintering areas. We review the current knowledge of the biology of the ortolan bunting and discuss the proposed causes of decline in relation to the different population trends in temperate and Mediterranean Europe. We suggest new avenues of research to identify the factors limiting ortolan bunting populations. The main evidence-based conservation measure that is likely to enhance habitat quality is the creation of patches of bare ground to produce sparsely vegetated foraging grounds in invertebrate-rich grassy habitats close to breeding areas.

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Integration of indigenous knowledge and ethnoscientific approaches into contemporary frameworks for conservation and sustainable management of natural resources will become increasingly important in policies on an international and national level. We set the scene on how this can be done by exploring the key conditions and dimensions of a dialogue between ‘ontologies’ and the roles, which ethnosciences could play in this process. First, the roles which ethnosciences in the context of sustainable development were analysed, placing emphasis on the implications arising when western sciences aspire to relate to indigenous forms of knowledge. Secondly, the contributions of ethnosciences to such an ‘inter-ontological dialogue’ were explored, based on an ethnoecological study of the encounter of sciences and indigenous knowledge in the Andes of Bolivia, and reviewed experiences from mangrove systems in Kenya, India and Sri Lanka, and from case-studies in other ecosystems world-wide.

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Glucocorticosteroid-induced spinal osteoporosis (GIOP) is the most frequent of all secondary types of osteoporosis. The understanding of the pathophysiology of glucocorticoid (GC) induced bone loss is of crucial importance for appropriate treatment and prevention of debilitating fractures that occur predominantly in the spine. GIOP results from depressed bone formation due to lower activity and higher death rate of osteoblasts on the one hand, and from increase bone resorption due to prolonged lifespan of osteoclasts on the other. In addition, calcium/phosphate metabolism may be disturbed through GC effects on gut, kidney, parathyroid glands and gonads. Therefore, therapeutic agents aim at restoring balanced bone cell activity by directly decreasing apoptosis rate of osteoblasts (e.g., cyclical parathyroid hormone) or by increasing apoptosis rate of osteoclasts (e.g., bisphosphonates). Other therapeutical efforts aim at maintaining/restoring calcium/phosphate homeostasis: improving intestinal calcium absorption (using calcium supplementation, vitamin D and derivates) and avoiding increased urinary calcium loss (using thiazides) prevent or counteract a secondary hyperparthyroidism. Bisphosphonates, particularly the aminobisphosphonates risedronate and alendronate, have been shown to protect patients on GCs from (further) bone loss to reduce vertebral fracture risk. Calcitonin may be of interest in situation where bisphosphonates are contraindicated or not applicable and in cases where acute pain due to vertebral fracture has to be manage. The intermittent administration of 1-34-parathormone may be an appealing treatment alternative, based on its documented anabolic effects on bone resulting from the reduction of osteoblastic apoptosis. Calcium and vitamin D should be a systematic adjunctive measure to any drug treatment for GIOP. Based on currently available evidence, fluoride, androgens, estrogens (opposed or unopposed) cannot be recommended for the prevention and treatment of GIOP. However, substitution of gonadal hormones may be indicated if GC-induced hypogonadism is present and leads to clinical symptoms. Data using the SERM raloxifene to treat or prevent GIOP are lacking, as are data using the promising bone anabolic agent strontium ranelate. Kyphoplasty performed in appropriately selected osteoporotic patients with painful vertebral fractures is a promising addition to current medical treatment.

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BACKGROUND: Abstracts of presentations at scientific meetings are usually available only in conference proceedings. If subsequent full publication of abstract results is based on the magnitude or direction of study results, publication bias may result. Publication bias, in turn, creates problems for those conducting systematic reviews or relying on the published literature for evidence. OBJECTIVES: To determine the rate at which abstract results are subsequently published in full, and the time between meeting presentation and full publication. To assess the association between study characteristics and full publication. SEARCH STRATEGY: We searched MEDLINE, EMBASE, The Cochrane Library, Science Citation Index, reference lists, and author files. Date of most recent search: June 2003. SELECTION CRITERIA: We included all reports that examined the subsequent full publication rate of biomedical results initially presented as abstracts or in summary form. Follow-up of abstracts had to be at least two years. DATA COLLECTION AND ANALYSIS: Two reviewers extracted data. We calculated the weighted mean full publication rate and time to full publication. Dichotomous variables were analyzed using relative risk and random effects models. We assessed time to publication using Kaplan-Meier survival analyses. MAIN RESULTS: Combining data from 79 reports (29,729 abstracts) resulted in a weighted mean full publication rate of 44.5% (95% confidence interval (CI) 43.9 to 45.1). Survival analyses resulted in an estimated publication rate at 9 years of 52.6% for all studies, 63.1% for randomized or controlled clinical trials, and 49.3% for other types of study designs.'Positive' results defined as any 'significant' result showed an association with full publication (RR = 1.30; CI 1.14 to 1.47), as did 'positive' results defined as a result favoring the experimental treatment (RR =1.17; CI 1.02 to 1.35), and 'positive' results emanating from randomized or controlled clinical trials (RR = 1.18, CI 1.07 to 1.30).Other factors associated with full publication include oral presentation (RR = 1.28; CI 1.09 to 1.49); acceptance for meeting presentation (RR = 1.78; CI 1.50 to 2.12); randomized trial study design (RR = 1.24; CI 1.14 to 1.36); and basic research (RR = 0.79; CI 0.70 to 0.89). Higher quality of abstracts describing randomized or controlled clinical trials was also associated with full publication (RR = 1.30, CI 1.00 to 1.71). AUTHORS' CONCLUSIONS: Only 63% of results from abstracts describing randomized or controlled clinical trials are published in full. 'Positive' results were more frequently published than not 'positive' results.

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A new scoring system, the Basic Erosive Wear Examination (BEWE), has been designed to provide a simple tool for use in general practice and to allow comparison to other more discriminative indices. The most severely affected surface in each sextant is recorded with a four level score and the cumulative score classified and matched to risk levels which guide the management of the condition. The BEWE allows re-analysis and integration of results from existing studies and, in time, should initiate a consensus within the scientific community and so avoid continued proliferation of indices. Finally, this process should lead to the development of an internationally accepted, standardised and validated index. The BEWE further aims to increase the awareness of tooth erosion amongst clinicians and general dental practitioners and to provide a guide as to its management.

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Patients with end-stage liver disease often reveal significant protein-energy malnutrition, which may deteriorate after listing for transplantation. Since malnutrition affects post-transplant survival, precise assessment must be an integral part of pre- and post-surgical management. While there is wide agreement that aggressive treatment of nutritional deficiencies is required, strong scientific evidence supporting nutritional therapy is sparse. In practice, oral nutritional supplements are preferred over parenteral nutrition, but enteral tube feeding may be necessary to maintain adequate calorie intake. Protein restriction should be avoided and administration of branched-chain amino acids may help yield a sufficient protein supply. Specific problems such as micronutrient deficiency, fluid balance, cholestasis, encephalopathy, and comorbid conditions need attention in order to optimize patient outcome.