共查询到20条相似文献,搜索用时 0 毫秒
1.
2.
3.
4.
5.
E.‐D. Schulze 《植被学杂志》2002,13(3):403-412
Abstract. Europe is characterized not only by large geomorphological variability but also by a long history of land use. This resulted in a highly variegated landscape. Based on the IGBP‐transect initiative, a north south transect was established across Europe ranging from north Sweden to central Italy in order to study effects of global change. Mainly process oriented studies were established on plots along the transect, and these were used to establish functional relationships as basis for landscape integration. However, it became apparent that the transect approach was not sufficient to mirror the European environment. From early on, the assessment of land cover was not constrained to this transect but complemented with measurements focused on Europe at a continental scale. Also, continental networks of flux measurements and ecosystem experiments were established, because these were able to encompass a larger inherent variability of climate, geology and land use. Resulting from the Kyoto protocol emphasis moved stronger from observations along transects towards a continental scale quantification of fluxes given the reporting needs. In this process the transect and the networks merged into research clusters, which provided a scaling and verification mechanism. Thus, the European situation may serve as an example of how the initial idea of transects has further evolved and broadened to continental scale studies in a region where anthropogenic land use dominates over climate change. 相似文献
6.
Sunil K Pandya 《BMJ (Clinical research ed.)》1990,301(6743):107-108
7.
S. K. Pandya 《BMJ (Clinical research ed.)》1988,297(6641):117-119
8.
9.
10.
Recent outbreak of avian-origin influenza A (H7N9) virus in the Yangtze River Delta area, China, expanding to neighboring areas in a later stage, with 36 deaths of 130 cases (as of May 16th) reminds the world of the threat 相似文献
11.
12.
Quan GM Carr D Schlicht S Powell G Choong PF 《International Seminars in Surgical Oncology : ISSO》2005,2(1):2
Adhesive capsulitis or frozen shoulder is a common condition characterized by shoulder pain and stiffness. In patients in whom conservative measures have failed, more invasive interventions such as arthrographic or arthroscopic distension can be very effective in relieving symptoms and improving range of movement. However, absolute contraindications to these procedures include the presence of neoplasia around the shoulder girdle. We present five cases referred to our institution where the diagnosis of shoulder joint malignancy was delayed, following prolonged, ineffective treatment for frozen shoulder. These cases highlight the importance of careful review of the radiology and the need for reconsideration of the diagnosis in refractory "frozen shoulder". 相似文献
13.
14.
15.
The annual reproductive cycle in the horse involves a reduction in ovarian activity during short days. The absence of ovulatory activity during winter has important consequences for an equine industry eager to breed mares early during the year. The anovulatory season results from a reduction in the secretion of pituitary gonadotropin that is in turn triggered by the inhibitory effects of short photoperiod on the hypothalamus–pituitary axis. Recent studies have provided evidence that the response of the ovaries to endocrine stimuli during the anovulatory season is affected not only by circulating concentrations of trophic hormones but also by locally produced growth factors that are putative modulators of follicular responses to gonadotropins. The present review summarises current knowledge on ovarian dynamics during the equine anovulatory season and the regulatory mechanisms involved at both systemic and local levels. 相似文献
16.
17.
Anne Gulland 《BMJ (Clinical research ed.)》2008,336(7653):1098-1100
19.
George Dunea 《BMJ (Clinical research ed.)》1978,2(6133):333-334
20.