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排序方式: 共有307条查询结果,搜索用时 218 毫秒
281.
Clara Barba Sonya Scott Alisa Roddick-Lanzilotta Rob Kelly Albert M. Manich Jose Luis Parra Luisa Coderch 《Fibers and Polymers》2010,11(7):1055-1061
In this work the effect on hair of two types of keratin samples obtained from wool, was investigated. Fiber surface changes
were evaluated by contact angle measurements. The effectiveness of these keratin ingredients to restore the mechanical properties
and the moisture content of the fibers was also determined. Modifications of hair properties due to some conventional chemical
treatments were demonstrated with lower values of contact angle and detrimental effects on the mechanical properties. Application
of keratin peptides and proteins to pretreated hair improved the fibers’ moisture content and their mechanical properties. 相似文献
282.
283.
Andrew W. Claridge Douglas J. Mills Rob Hunt David J. Jenkins Josh Bean 《Forest Ecology and Management》2009
Satellite tracking was used to follow the movements of a problematic top-order carnivore, the wild dog (Canis lupus dingo, C. lupus familiaris and their hybrids), in contiguous forested landscapes in south-eastern mainland Australia. Home range sizes of wild dogs were much larger than previously determined using conventional telemetry methods, averaging 10,000 ha with a maximum size of 59,000 ha over approximate 3-month periods. Wild dogs at sites with high abundance of kangaroos, wallabies and rabbits had smaller areas of occupancy than did dogs at sites with low availability of these preys. Despite mostly large home ranges, tracked animals were loyal to publicly-owned tenure and there were few instances where individuals moved large distances on to adjacent private tenure. Instead, movement behaviours of most tracked animals were characterised by repeated short distance forays, often at acute angles from previous locations. Consequently, home ranges were stable and otherwise well defined. Analysis of DNA from our study animals indicated that most individuals were of ‘dingo’ ancestry, but otherwise considered hybrids because of the presence of domestic dog genes. Only two of 24 animals could be considered as ‘pure’ dingo. Contemporary wild dog management demarcates lands where control is or is not undertaken, with the latter notionally acting to ‘conserve’ dingoes. Due to the large scale of movement of animals, existing control efforts likely impact over a greater area than previously suspected. Furthermore, our genetic findings suggest that conservation of dingoes in south-eastern mainland Australia is difficult to achieve. A modified approach to wild dog management is needed, taking account of the extent of range of individual animals and the existing genetic characteristics of populations. 相似文献
284.
ABSTRACT A new tospovirus species serologically distinct from all other established tospoviruses was found in tomato in Iran. Typical disease symptoms observed include necrotic lesions on the leaves and yellow ring spots on the fruits, hence the name Tomato yellow ring virus (TYRV) was proposed. The S RNA of this virus was cloned and its 3,061 nucleotide long sequence showed features characteristic for tospoviral S RNA segments. The nucleocapsid (N) protein with a predicted Mr of 30.0 kDa showed closest relationship to the N protein of Iris yellow spot virus (74% sequence identity). 相似文献
285.
Rob L Coke Kay A Backues John P Hoover Jeremiah T Saliki Jerry W Ritchey Gary D West 《Journal of zoo and wildlife medicine》2005,36(2):326-330
Fennec foxes (Vulpes zerda) and meerkats (Suricata suricatta) are considered to be susceptible to canine distemper virus (CDV) infection. Although no definitive clinical cases of natural CDV infections have been reported, mortalities due to CDV have been suspected and are reported in other closely related species. A commercially available monovalent, live, canarypox-vectored CDV vaccine induced neutralizing antibody titers that were maintained for at least a year in both fennec foxes and meerkats. 相似文献
286.
287.
Sander Wijnhoven Ivo Thonon Gerard Van Der Velde Rob Leuven Mathilde Zorn Herman Eijsackers Toine Smits 《Water, air, and soil pollution》2006,177(1-4):183-210
Floodplains along large European rivers are diffusely polluted with heavy metals due to emissions in the past. Because of low mobility of heavy metals in floodplain soils and improvements of water quality, these pollutants will remain in place, and can gradually become covered with less contaminated sediments. Bioturbators, especially earthworms, can play an important role in the mixing and surfacing of contaminated substrate. Surfaced substrate can be redistributed by recurrent flooding events, even to areas outside the floodplain. The question remained to what extent bioturbation by small mammals contributes to the redistribution of heavy metals from river sediments in floodplains. Extensive fieldwork on bioturbators such as voles, moles and earthworms and their distribution patterns, as well as on sediment deposition and bioturbation, was conducted at the ‘Afferdensche en Deestsche Waarden’ floodplain over the years 2001–2003. Field data were combined with data of experiments in field enclosures and substrate columns to calculate the amounts of sediment and heavy metals (Zn, Cu, Pb and Cd) redistributed during the floods as well as on an annual basis. Moles and voles surfaced considerable amounts of substrate and heavy metals, but not as much as earthworms which contribute a substantial proportion of the total deposition and redistribution during floods. Although the impact of moles and voles on the redistribution during floods was only locally important, on an annual basis the bioturbation activity of especially moles in floodplains cannot be neglected. The annual amounts of substrate and heavy metals surfaced by all investigated bioturbators were even larger than the total amounts of substrate and heavy metals deposited during floods. 相似文献
288.
Rob H Marrs 《Biological conservation》2002,108(1):131
289.
Miettinen SM Hyvönen L Linforth RS Taylor AJ Tuorila H 《Journal of agricultural and food chemistry》2004,52(26):8111-8118
A temporal aroma delivery from milk systems containing 0, 0.5, or 5% added fat and flavored with seven-component strawberry flavoring and linalool was observed by free choice profiling (FCP), time intensity (TI), and atmospheric pressure chemical ionization-mass spectrometry (APCI-MS) techniques. A suppressing effect of fat on the volatility of the relatively nonpolar compound linalool was observed by all methods, but only slight evidence (with the TI method) of the effect of fat on the overall strawberry (based on more polar compounds) intensity was found. With the TI method, the strawberry aroma of the fattiest sample lingered the longest, but no temporal differences were found in the release of linalool. The APCI-MS results showed no effect of fat on the temporal release of ethyl butyrate (mainly responsible for the strawberry note), but linalool of the sample containing 5% fat was found to be the most persistent. However, the effect on linalool was observed using a slightly different sampling technique than in the TI. Overall, FCP, TI, and APCI-MS showed parallel results for the effect of fat on the intensity of aroma, but temporal release data only partly supported the theory that fat slows down the release of aroma compounds and their perception. 相似文献
290.
Ambiguity exists about the level of genetic diversity represented by farmer crop varieties, how it develops over time and
how it relates to the diversity comprised by formal varieties. As part of an interdisciplinary technological/sociological
study on farmer management of gene flow, upland rice (Oryza sativa L.) and late millet (Pennisetum glaucum (L.) R.Br.) from The Gambia were investigated for morphological and molecular variation. The goal of these analyses was to
obtain insight into the level of crop genetic diversity of farmer’s materials planted in several case study villages in The
Gambia. For both crops, samples were collected from villages and various research institutes. Based on variety names, different
rice and millet varieties were expected to be used in different villages. In fact, there was a large overlap in genetic diversity
for both crops, masked by the use of synonyms. The considerable similarity in rice genetic diversity between villages most
likely results from the exchange of varieties between farmers. For millet this seems the result of development of varieties
from the same gene pool. Some farmer varieties of rice, however, are apparent hybrid forms between the species O. sativa and O. glaberrima Steud., and farmer varieties in general displayed higher levels of genetic diversity than formal varieties. This indicates
that, for rice, genetic diversity develops in farmers’ fields and may have potential use in formal breeding programs. 相似文献