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121.
At the Agricultural Research Institute, Hillsborough, Northern Ireland, during September and October, 1958, a field which was naturally infected with Dictyocaulus viviparus (lungworm) larvae was divided and one part was intensively grazed by cows which were not excreting lungworm larvae while the other part remained unstocked. Records were kept of the available herbage, total dry matter and the numbers of larvae on both areas. Grazing resulted in a marked reducuon of the larval numbers which was greater, in proportion, than that of the amount or herbage. Although severe grazing did not remove the infection, it so accelerated the decline in numbers that an infection level of one larva per lb. herbage was reached 7 weeks earlier on the grazed than on the ungrazed area. The herbage in both areas showed no larvae about 4 months after infected faeces were last voided on to it. 相似文献
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124.
Glucocorticoid receptors in lymphoma cells in culture: relationship to glucocorticoid killing activity 总被引:17,自引:0,他引:17
Mouse lymphoma cells in culture which are killed by adrenal steroids contain specific cortisol receptors that may be involved in the initial events of hormone action. The similarity of these receptors to those in hepatoma tissue culture cells, where adrenal steroids induce tyrosine aminotransferase, suggests that certain aspects of steroid action are similar in the two systems. In three steroid-resistant lymphoma cell populations specific binding was less than in the parent lines, suggesting that conversion to steroid resistance may be associated with changes in specific steroid binding. 相似文献
125.
Structure of recombinant human renin, a target for cardiovascular-active drugs, at 2.5 A resolution 总被引:6,自引:0,他引:6
A R Sielecki K Hayakawa M Fujinaga M E Murphy M Fraser A K Muir C T Carilli J A Lewicki J D Baxter M N James 《Science (New York, N.Y.)》1989,243(4896):1346-1351
The x-ray crystal structure of recombinant human renin has been determined. Molecular dynamics techniques that included crystallographic data as a restraint were used to improve an initial model based on porcine pepsinogen. The present agreement factor for data from 8.0 to 2.5 angstroms (A) is 0.236. Some of the surface loops are poorly determined, and these disordered regions border a 30 A wide solvent channel. Comparison of renin with other aspartyl proteinases shows that, although the structural cores and active sites are highly conserved, surface residues, some of which are critical for specificity, vary greatly (up to 10A). Knowledge of the actual structure, as opposed to the use of models based on related enzymes, should facilitate the design of renin inhibitors. 相似文献
126.
Temperature (T)- and frequency (omega)-dependent conductivity measurements are reported here in amorphous niobium-silicon alloys with compositions (x) near the zero-temperature metal-insulator transition. There is a one-to-one correspondence between the frequency- and temperature-dependent conductivity on both sides of the critical concentration, thus establishing the quantum-critical nature of the transition. The analysis of the conductivity leads to a universal scaling function and establishes the critical exponents. This scaling can be described by an x-, T-, and omega-dependent characteristic length, the form of which is derived by experiment. 相似文献
127.
- This article introduces a special issue of Aquatic Conservation: Marine and Freshwater Ecosystems (AQC) whose contributions demonstrate examples of the practical impact of the authors' previous AQC articles on the conservation of aquatic ecosystems.
- The submitting authors of all articles published in AQC since 2009 were invited to express their interest in writing an article for the special issue. The 20 articles selected for publication discuss 33 AQC articles published from 2004 to 2019, spanning a wide range of geographical locations, habitat types, species groups, and impacts on aquatic conservation.
- The two impacts reported most frequently are ‘Undertaking practical management of habitats and species’ and ‘Establishing partnerships’, closely followed by ‘Restoring habitats/reintroducing or translocating species’. Many authors demonstrate the importance of their articles in raising awareness across an extensive range of organizations.
- Some impacts occur soon after publication (e.g. introduction of conservation guidelines), whereas others (e.g. influencing policy) take far longer. Authors report a wide range of methods for disseminating research results appropriate for different audiences, such as technical handbooks, seminars, magazine articles, media broadcasts, and field workshops.
- To assess whether ‘conventional’ measures of impact match authors' perceptions, three metrics were calculated for the 33 AQC articles discussed in this issue: the number of citations, the number of downloads, and the Altmetric Attention Score. These metrics were not significantly higher for the 33 articles than the corresponding median metrics of the articles in the issues in which the 33 were published.
- The goal of AQC is to continue to encourage scientists to recognize and promote the application of their research to practical conservation and management. Given the growing threats to aquatic ecosystems, much remains to be done to make this process even more effective.
128.
Bista Damber Baxter Greg S. Hudson Nicholas J. Lama Sonam Tashi Murray Peter John 《Landscape Ecology》2022,37(3):795-809
Landscape Ecology - Habitat specialists residing in human-modified landscapes are likely to be more vulnerable to disturbance because of a functional reliance on very particular habitat features.... 相似文献
129.
GP REPPAS 《Australian veterinary journal》1995,72(11):425-427
SUMMARY Two adult cattle died within 48 h of being fed a large amount of Bryophyllum pinnatum plants collected from a house garden. Clinical signs became apparent the day after feeding and included hypersalivation, ataxia, severe cardiac arrhythmia and laboured respiration. The main necropsy findings were acute rumenitis, reduction of bronchiolar lumens and emphysema. 相似文献
130.