排序方式: 共有27条查询结果,搜索用时 15 毫秒
21.
Fangzhou Li Jiangshan Zhou Chun Du Wei Li Yinzhen Wang Guannan He Qinyu He 《环境科学学报(英文版)》2017,29(10):24-32
A one-step microwave irradiation method was used to deposit carbon and nitrogen co-doped TiO_2((C, N)-TiO_2) on commercial brick((C, N)-TiO_2/brick). The as-prepared samples were characterized by X-ray diffraction, ultraviolet–visible(UV–vis) diffuse reflectance spectroscopy, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy(SEM). A selective technique was also used to investigate the concentration of hydroxyl radicals during UV–vis irradiation of the Methyl Orange solution with the as-prepared samples. The C and N dopants enhanced visible light absorption and provided a longer lifetime for the photo-generated electron–hole pairs. The SEM images showed that the as-prepared sample is porous. The dark adsorption and photodegradation test for(C, N)-TiO_2/brick showed good photodegradation and good recyclability. The best photodegradation rate was 94% after 2 hr. The maximum degradation rate was maintained even after the 6th cycle. The good photocatalytic properties are attributed to the enhanced visible light absorption, enhanced pollutant adsorption arising from the porous structure of the(C, N)-TiO_2 thin film, and longer lifetime of the photo-generated electron–hole pairs.(C, N)-TiO_2/brick should have potential commercial applications in photodegradation processes because of its low cost, good photodegradation, and excellent recyclability. 相似文献
22.
Divorce and extrapair mating in female black-capped chickadees (Parus atricapillus): separate strategies with a common target 总被引:1,自引:0,他引:1
S. M. Ramsay K. A. Otter D. J. Mennill L. M. Ratcliffe P. T. Boag 《Behavioral ecology and sociobiology》2000,49(1):18-23
Patterns of divorce and extrapair mating can provide insights into the targets of female choice in free-living birds. In resident,
site-faithful species with continuous partnerships, the better options and the incompatibility hypotheses provide the most
likely explanations for divorce. Extrapair mating can be explained by a number of hypotheses often making similar predictions.
For example, the good genes and future partnerships hypo- theses predict similar patterns if males with good genes also make
the best future partners. By considering both divorce and extrapair mating, it may be possible to distinguish between these
comparable hypotheses. We examined natural patterns of divorce and extrapair mating in a long-term study of black-capped chickadees
(Parus atricapillus). Out of 144 partnerships over 8 years, we observed 11 divorces and 38 faithful pairs between seasons. Females usually divorced
between their first and second breeding seasons for males of higher social rank than their previous partners, had similar
reproductive success prior to divorce as females who retained their previous partners, and did not divorce on the basis of
previous reproductive success. These results confirm earlier experimental evidence that females divorce for better options.
Females who divorced were significantly more likely to have had mixed-paternity broods prior to divorce than females who stayed
with their previous partners. There was no evidence that females divorced in favour of previous extrapair partners. These
results support the good genes hypothesis for extrapair mating, suggesting that female chickadees use divorce and multiple
mating as separate strategies sharing a common target.
Received: 4 February 2000 / Revised: 20 July 2000 / Accepted: 4 September 2000 相似文献
23.
Alison J. Gilbert Abigail McQuatters-Gollop Olivia Langmead Laurence Mee Jan Vermaat 《Ambio》2015,44(2):142-153
We augment discussions about the Good Environmental Status of the North Sea by developing two extreme visions and assessing their societal benefits. One vision (‘Then’) assumes restoration of benthic functioning; we contend that trawling had already degraded the southern North Sea a century ago. Available information is used to speculate about benthic functioning in a relatively undisturbed southern North Sea. The second vision (‘Now’) draws on recent benthic functioning. The supply of five ecosystem services, supported by benthic functioning, is discussed. ‘Then’ offers confidence in the sustainable supply of diverse services but restoration of past function is uncertain and likely to be paired with costs, notably trawling restraints. ‘Now’ delivers known and valued services but sustained delivery is threatened by, for example, climate change. We do not advocate either vision. Our purpose is to stimulate debate about what society wants, and might receive, from the future southern North Sea.
Electronic supplementary material
The online version of this article (doi:10.1007/s13280-014-0536-5) contains supplementary material, which is available to authorized users. 相似文献24.
董春亮 《中国个体防护装备》2011,(5):51-53
本文结合制药装备贯彻国家2010版《药品生产质量管理规范》(GMP)要求,对既是药品生产重要手段,又是不可忽视的污染因素之一的制药装备,从确保药品安全和药品生产质量的设计角度浅析,启发制药装备功能与结构的研发思路。 相似文献
25.
Adeline Loyau Michel Saint Jalme Robert Mauget Gabriele Sorci 《Behavioral ecology and sociobiology》2007,61(7):1043-1052
According to the differential investment hypothesis, females paired with attractive mates are expected to invest more in the
current reproduction relative to females paired with unattractive males. We experimentally tested this hypothesis in the peafowl
(Pavo cristatus) by providing females with males that differed in sexual attractiveness. In agreement with the differential allocation hypothesis,
females paired with more ornamented males laid larger eggs, and deposited higher amounts of testosterone into the egg yolk,
independently of the sex of the embryo. These results show that the association between paternal phenotype and offspring quality
could arise via a differential maternal investment. They also suggest that, if ornamented males do transmit good genes to
the progeny, the maternal differential investment can amplify the effect of such good genes on the offspring fitness. 相似文献
26.
Extra-pair paternity is common in socially monogamous passerines; however, despite considerable research attention, consistent
differences in fitness between within-pair offspring (WPO) and extra-pair offspring (EPO) have not been demonstrated. Recent
evidence indicates that differences between maternal half-siblings may depend on environmental conditions, but it is unclear
whether the influence of paternal genetic contribution should be most apparent under comparatively poor or favourable conditions.
We compared phenotypic characteristics of WPO and EPO in 30 mixed-paternity broods of the tree swallow (Tachycineta bicolor) in relation to experimentally increased nest temperature (n = 13 heated nests; 17 control nests) and natural abundance of haematophagous parasites (Protocalliphora spp.). This allowed us to test the hypothesis that genetic benefits of extra-pair mating are environment dependent. EPO grew
their ninth primary feathers faster than WPO regardless of nest temperature or parasite load and had significantly longer
ninth primary feathers at fledging when parasite abundance was low, and when they were positioned early in the hatching sequence
relative to WPO. In contrast, WPO under similar conditions did not differ from EPO in any phenotypic trait measured. These
results indicate that the fitness benefits of extra-pair mating are likely to be context dependent, and that genetic effects
on some phenotypic traits may be more apparent when conditions are relatively favourable. 相似文献
27.
The UNFCCC requires REDD+ countries wishing to receive results-based payments to measure, report and verify (MRV) REDD+ impacts; and outlines technical guidelines and good governance requirements for MRV. This article examines institutional effectiveness of REDD+ MRV by assessing countries’ progress in implementing these technical guidelines and good governance requirements, from three dimensions. Ownership of technical methods examines whether countries own technical methods for forest area and area change measuring, and for estimating forest carbon stocks; and whether national MRV systems cover all forests, land uses and carbon pools. Administrative capacity examines development of administrative competence to implement MRV. Good governance examines whether countries espouses norms of good governance in their MRV systems. We apply these dimensions to assess and compare progress in 13 REDD+ countries, based on a review of national and international documents. Findings show that REDD+ countries have high to very high ownership of technical methods. However, majority ranks only low to moderate on administrative capacity and good governance. This means that although countries have started developing technical methods for MRV, they are yet to develop the competence necessary to administer MRV and to inculcate good governance in MRV. The article explain the scores and suggest ways of improving implementation of REDD+ MRV. 相似文献