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排序方式: 共有250条查询结果,搜索用时 15 毫秒
131.
Heong KL Chen YH Johnson DE Jahn GC Hossain M Hamilton RS 《Science (New York, N.Y.)》2005,310(5746):231-3; author reply 231-3
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135.
Jahn P Johnsen 《Fish and Fisheries》2014,15(3):428-444
Are there limits to the governability of a fishery? The establishment of a 200 nautical mile economic zone in Norway in 1977 made it possible to change from an open‐access regime to a more closed one. In this process, the former self‐regulating Norwegian fishing industry, to a large extent, accepted and adapted an explicit, hierarchical form of state‐run governance. However, the process of change did not stop there. Since the turn of the millennium, we have seen the creation of a cybernetically organized fishing industry, where control, regulation and governance have become re‐embedded in the industry. This article explores this radical new development and perspective on fisheries governance and governability based on lessons learned from technological and organizational changes in the Norwegian fishing industry. 相似文献
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137.
Hemmann K Raekallio M Kanerva K Hänninen L Pastell M Palviainen M Vainio O 《Veterinary journal (London, England : 1997)》2012,193(1):97-102
Crib-biting is classified as an oral stereotypy, which may be initiated by stress susceptibility, management factors, genetic factors and gastrointestinal irritation. Ghrelin has been identified in the gastric mucosa and is involved in the control of food intake and reward, but its relationship to crib-biting is not yet known. The aim of this study was to examine the concentration and circadian variation of plasma ghrelin, cortisol, adrenocorticotropic hormone (ACTH) and β-endorphin in crib-biting horses and non-crib-biting controls. Plasma samples were collected every second hour for 24h in the daily environment of eight horses with stereotypic crib-biting and eight non-crib-biting controls. The crib-biting horses had significantly higher mean plasma ghrelin concentrations than the control horses. The circadian rhythm of cortisol was evident, indicating that the sampling protocol did not inhibit the circadian regulation in these horses. Crib-biting had no statistically significant effect on cortisol, ACTH or β-endorphin concentrations. The inter-individual variations in β-endorphin and ACTH were higher than the intra-individual differences, which made inter-individual comparisons difficult and complicated the interpretation of results. Further research is therefore needed to determine the relationship between crib-biting and ghrelin concentration. 相似文献
138.
Governability is an important concept in the political and environmental social sciences with increasing application to socio‐ecological systems such as fisheries. Indeed, governability analyses of fisheries and related systems such as marine‐protected areas have generated innovative ways to implement sustainability ideals. Yet, despite progress made, we argue that there remain limitations in current conceptions of governability that hinder further analytical development and use. By drawing on general systems theory—specifically cybernetics, control and feedback—we interrogate the conceptual foundations that underpin two key limitations: the need to incorporate the numerous variables that comprise a complex, holistic system into a singular assessment of governability, and the a priori separation of the governor and the governed that precludes analysis of a self‐governing situation. We argue that by highlighting the reciprocal nature of a governor–governed relationship and the co‐produced understanding of governing capacity and objects, a relational approach to governability is possible. This offers a clearer and more pragmatic understanding of how governors and fishers can make fisheries governable. 相似文献
139.
Else Jahn 《Journal of pest science》1977,50(8):113-115
Influence of biophysical and electrical fields on Lymatria monacha l. 2: Caterpillar migrations, Faraday experiments, physical measurements The abstract for the whole paper was given in Pt. 1 (this journal, 7/1977 p.97). 相似文献
140.
Professor Dr. Else Jahn 《Journal of pest science》1981,54(8):114-120
The examinations of caterpillars migrations ofLymantria monacha 1974/75 in respect of biophysical food-sources: food (RF) of zones of earth radiations (RZ) and food (NF) of normal zones (NF) in connection to certain developmental stages with cut branches of spruces and the possibility of movement in West-East direction (Jahn, 1977) were repeated 177/78 with living plants (Larix japonica) in North-South direction. It could be stated, that also the direction North-South was of certain influence on caterpillars migrations. In respect to food the results 1977 were like those from 1974/75 (RF in RZ) and of preceding mortality investigations. But 1978 the results some-what contrasted with the former ones. The behaviour 1978 might correlate with increasing solar-activity in this year, like thisBecker (1980) found for the feeding activity rhythms of termites in 1978 and 1979. The attraction of the food-sources in the ranges investigated: RZ South — NZ North and NZ South — RZ North was similar in northern and southern larch-stands, somewhat promoted or restricted, as some controls showed, from the influence of direction. It could be proved on spruces lying in fluctuating zones (sudden changes of RZ and NZ) for the attack of scolytid beetles besides volatiles attractants of bark and already breeding beetles (pheromones) and climate condition also biophysical fields are of importance. A good coincidence was given between attacked stem-regions and RZ during cool weather conditions. But when warm weather was prevailing — this only could be stated for the beginning of the flight period. Probably attractants of bark and beetles released more concentrated are responsible for an extent of invasion of the scolytids from RZ to NZ. In gradation areas ofCephalcia abietis in “Waldviertel” (Lower Austria) where this pamphyliid causes severe damages on spruces inside of RZ or fluctuating zones, in soils of fluctuating zones larvae in state of latency were more numerous in NZ than in RZ. It is assumed that strong influence of biological fields does not be favourable for larvae in these states. 相似文献