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生态足迹评价体系,可以在一定程度上刻画区域社会经济发展对当地生态环境产生的影响,当前可持续发展研究的难点之一,便是如何更加真实的体现这种影响。立足于传统生态足迹模型,采用“一年一区一值”的参数方案计算区域当年均衡因子与产量因子,结合土地利用转移矩阵和建设用地流入量改进建设用地足迹算法,对北疆地区2005年、2010年、2015年、2018年生态足迹及生态承载力进行测度,并结合相关指数对研究区发展的可持续性进行评价。结果表明:(1)北疆生态足迹增涨3.5倍,且以能源增长为主导,生物生产性足迹贡献率大幅下降;人均生态足迹增长3.4倍,工业型城市生态足迹增长率及人均生态足迹增长率均高于其他类型城市。(2)研究区生态承载力呈现上升态势,除水域和草地外,其他地类承载力均呈上升态势,昌吉州与阿勒泰地区的总体承载力及人均承载力均呈下降态势。(3)北疆生态利用效率上涨1.32倍,各行政单元呈现农业及服务业型城市生态利用效率上升、工业型城市生态利用效率降低的态势,表明工业型城市生态足迹增速远高于经济增速。(4)各行政单元呈现生态赤字状态且不断加剧,总体及人均增速都呈现工业型>农业型>服务业型...  相似文献   

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Studies were conducted on dogs to test the efficacy of cyclosporin A (CyA) in prolonging normoglycaemia and graft survival after whole-organ pancreas allograft transplantation. Five dogs subjected to pancreatectomy alone served as controls. Withholding immunosuppression after transplantation (five animals) resulted in the same median duration of survival as occurred in the controls (13 days). Azathioprine and steroids (seven animals) produced median durations of normoglycaemia and survival of 9 and 23 days respectively. Animals given CyA 18 mg/kg/day (five) and 25 mg/kg/day (10), however, showed median durations of normoglycaemia of 18 and 55 days (p less than 0.05 and p less than 0.02) respectively and median survival times of 36 and 85 days (NS and p less than 0.02). If CyA proved effective in controlling rejection of pancreas allografts in man it would offer unstable diabetics in renal failure a more hopeful outlook than conventional immunosuppression.  相似文献   

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The goal of this project was to identify conditions that result in development from the zygote or the 2-cell stage Sinclair miniature pig embryos to the blastocyst stage. Four media were selected, 2 that have been shown to result in in vitro development in domestic pigs (Hepes buffered Tyrode's medium and Whitten's medium), 1 that is compatible with similar development in the cow (CR-1), and 1 that is compatible with development in the mouse (CZB). One- and two-cell stage embryos from Sinclair miniature pigs were flushed from oviducts in Hepes buffered Tyrode's medium, allocated to 1 of the 4 media and cultured for 120 h. At the end of the culture period, embryos were morphologically scored and nuclei were counted. Morphology scores were lowest for Hepes buffered Tyrode's medium but were not different for Whitten's medium, CZB or CR-1. The highest (P < 0.07) number of nuclei was present in the oocytes cultured in Whitten's medium (21.3), with CR-1 (15.7) and CZB (16.5) not differing significantly. Similar to the morphology scores, Hepes buffered Tyrode's medium resulted in the lowest number nuclei (5.5). In a parallel experiment, domestic pig embryos were cultured in Hepes buffered Tyrode's medium versus Whitten's medium. The domestic pig embryos, while also developing better in Whitten's Medium, developed better in the Hepes buffered Tyrode's medium than did the embryos from Sinclair pigs. Thus, the Sinclair pig embryo develops best if placed in Whitten's Medium.  相似文献   

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Since the annotation of its genome a decade ago, the dog has proven to be an excellent model for the study of inherited diseases. A large variety of spontaneous simple and complex phenotypes occur in dogs, providing physiologically relevant models to corresponding human conditions. In addition, gene discovery is facilitated in clinically less heterogeneous purebred dogs with closed population structures because smaller study cohorts and fewer markers are often sufficient to expose causal variants. Here, we review the development of genomic resources from microsatellites to whole‐genome sequencing and give examples of successful findings that have followed the technological progress. The increasing amount of whole‐genome sequence data warrants better functional annotation of the canine genome to more effectively utilise this unique model to understand genetic contributions in morphological, behavioural and other complex traits.  相似文献   

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Summary Vegetation development in a former orchard on loamy moist soil after removal of the fruit trees under different treatment is described with the help of multivariate methods. Data on 20 plots over 9 years are treated with a simple classification program and a PCA ordination. Two main groups of plots are involved: one in a relatively moist part of the area where the trees were removed in 1970, one in a slightly drier area where the trees had been removed earlier. The first group is characterized by forbs such as Urtica dioica and Lamium maculatum, the second by grasses, mainly Arrhenatherum elatius.Under a mowing regime the plots of the first group change in the direction of the second group. Under continued fertilization the Urtica vegetation can be maintained. Establishment and/or rapid spread of Urtica can be brought about in Arrhenatherum dominated sites by (re-) introduction of nitrogen fertiliser.Not mowing leads to a dense Urtica-Lamium stand in which Lamium maculatum finds an optimum some years after mowing is stopped.The methods of summarizing the site-time data are discussed and some new ones announced for further research.Nomenclature follows Heukels-van Ooststroom, Flora van Nederland, 18e druk, Wolters-Noordhoff, Groningen, 1975.Vegetation and soil analyses were mainly carried out by students in the framework of their study for the degree of doctorandus in biology: Ineke Opbroek, Ferdinand Baggerman (1970), Carla Veldhuis (1971–1972), the late Doeke Dijken (1971–1973), Jos Rijpert (1972), the Rev. Piet van der Aart, Jo Louppen (1973), Frank Verhoeven (1974), Maurits Heine (1975), Ad Peters (1976), Huub Muyres, Louis Fliervoet (1976, 1977), Emilia Peters (1977), Niek Joanknecht, Thijs Lavrijsen (1977, 1978).  相似文献   

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This article presents a methodology for conceiving and planning the development of an optimized supply chain of a biodiesel plant sourced from family farms and taking into consideration agricultural, logistic, industrial, and social aspects. This model was successfully applied to the production chain of biodiesel fuel from castor oil in the semi-arid region of Brazil. Results suggest important insights related to the optimal configuration of the crushing units, regarding its location, technology, and when it should be available, as well as the configuration of the production zones along the planning horizon considered. Moreover, a sensitivity analysis is performed in order to measure how possible variations in the considered conjecture can affect the robustness of the solutions.  相似文献   

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The temporalis: blood supply and innervation   总被引:3,自引:0,他引:3  
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This study formulates a model to maximize the profit of a lignocellulosic biofuel supply chain ranging from feedstock suppliers to biofuel customers. The model deals with a time-staged, multi-commodity, production/distribution system, prescribing facility locations and capacities, technologies, and material flows. A case study based on a region in Central Texas demonstrates application of the proposed model to design the most profitable biofuel supply chain under each of several scenarios. A sensitivity analysis identifies that ethanol (ETOH) price is the most significant factor in the economic viability of a lignocellulosic biofuel supply chain.  相似文献   

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运用复种指数调整后的生态足迹模型,利用江苏省的相关统计资料以及GIS技术,对1999-2008年间江苏省六大经济区的生态足迹变化进行了比较分析,并在此基础上进一步对江苏省六大经济区的资源利用效率、生态经济协调性以及社会经济发展趋势予以探讨。研究发现当前江苏省六大经济区处于不同程度的生态赤字状态。基于生态足迹计算结果,进一步引入万元GDP生态足迹、生态经济弹性系数以及可持续发展能力三项指标,从资源利用效率,生态经济协调性以及社会经济综合发展趋势三方面来综合分析评价江苏省六大经济区的可持续发展状况,最终结果显示尽管区域间发展水平有明显差异,但是整个江苏省的可持续发展能力水平在不断提高,总体状况良好。最后根据江苏省六大经济区的可持续发展水平,提出了进一步协调区域间平衡发展的相关建议。  相似文献   

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Sperm acrosome is known to play a role in the fertilization of the majority of animal species studied. As a general rule, the acrosome appeared as soon as the fertilization occurred out of aquaeous phase. The biochemical content of acrosome as well as its release mode could suggest it is a simple lysosome. But this would by pass its important morphogenic role in spermiogenesis. Its development is strongly linked to the development of the microtubules manchette system.Molecular data of animal mutagenesis contribute to the understanding of acrosome biogenesis mechanisms. Globozoospermia is a rare but severe human teratozoospermia, characterized by ejaculates entirely consisting of round-headed spermatozoa that lack an acrosome. It originates from a disturbed acrosome biogenesis. Recently, the genetic study of a familial globozoospermia led to highlight a homozygote mutation of the gene SPATA16, linked to the globozoospermic phenotype. This study contributes to the understanding of the mechanisms implied in human acrosome formation.  相似文献   

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A list of ten culture-specific symptoms frequently volunteered by Nigerian patients with Minor Psychiatric Disorders was added to the twenty items of the SRQ-20. The resultant 30-item questionnaire (SRQ-30) discriminated very well between a sample of new non-psychotic psychiatric referrals and a sample of subjects with very low probability of caseness (relatives of the new psychiatric referrals). Elimination of items of the SRQ-30 which poorly discriminated between the sample of psychiatric referrals and a matched sample of general hospital patients (ten items) produced the Nigerian version of the SRQ-20 (NSRQ-20) whose sensitivity is shown to be higher than that of the SRQ-30. Further validation study and future research trends on the NSRQ-20 are suggested.  相似文献   

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