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51.
Kuber Prasad Bhatta Harry John Betteley Birks John-Arvid Grytnes Ole Reidar Vetaas 《Journal of Plant Ecology》2019,12(3):460
Aims
Studies of the climatic responses of plant assemblages via vegetation-based environmental reconstructions by weighted averaging (WA) regression and calibration are a recent development in modern vegetation ecology. However, the performance of this technique for plot-based vegetation datasets has not been rigorously tested. We assess the estimation accuracy of the WA approach by comparing results, mainly the root mean square error of prediction (RMSEP) of WA regressions for six different vegetation datasets (total species, high-frequency species and low-frequency species as both abundance and incidence) each from two sites. 相似文献
52.
Use of in vivo and in vitro assays for the characterization of mammalian excision repair and isolation of repair proteins 总被引:6,自引:0,他引:6
Elucidation of the molecular mechanism of mammalian nucleotide excision repair requires the availability of purified proteins, DNA substrates with defined lesions and suitable repair assays. Repair assays introduced in recent years vary from testing individual steps and successions of steps in vitro to systems that closely reflect the entire process in vivo. In the first part of this review, an in vivo microinjection system is discussed. The second part of the article reviews an in vitro system for study of repair synthesis promoted by cell extracts. Both systems can be utilized as assays during the purification of protein factors that complement repair-defective xeroderma pigmentosum cells. The effect of purified repair proteins from other organisms on mammalian repair is also considered. 相似文献
53.
54.
Regulation of parental investment in the Antarctic petrel Thalassoica antarctica: an exchange experiment 总被引:1,自引:0,他引:1
An experiment was conducted on the Antarctic petrel to test whether the parents were able to respond to changes in food demand of their offspring. Two experimental groups were formed by replacing eight 20-day-old chicks with 10-day-old chicks, and vice versa. The growth rate of chicks in the experimental groups was compared with that in two control groups with chicks of known age. The growth rate of 10-day-old chicks in the nests of parents which initially had 20-day-old chicks did not differ significantly from that in their respective control groups. This indicates that those parents were able to raise a new young nestling, despite having already raised another chick from hatching to 20 days. However, the 20-day-old chicks placed in nests with 10-day-old chicks had a significantly lower growth rate than their control group. Feeding rate per day and nest did not differ significantly among any of the groups. This suggests that the observed difference in growth rate between 20-day-old chicks is related to a lower amount of food delivered per visit to experimental chicks. Thus, in the Antarctic petrel, the feeding rate apparently is not regulated by the status of the chick, but by the parents' ability to gather food or willingness to provide food for the chicks.Publication no. 137 from the Norwegian Antarctic Research Expedition (NARE) 1989/90 相似文献
55.
XPC and human homologs of RAD23: intracellular localization and relationship to other nucleotide excision repair complexes. 总被引:11,自引:3,他引:8
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P J van der Spek A Eker S Rademakers C Visser K Sugasawa C Masutani F Hanaoka D Bootsma J H Hoeijmakers 《Nucleic acids research》1996,24(13):2551-2559
56.
Di Zhang Vincent H. Ng Zhaochen Wang Xiaomei Zhai Reidar K. Lie 《Developing world bioethics》2016,16(2):107-115
The application of genetic technologies in China, especially in the area of prenatal genetic testing, is rapidly increasing in China. In the wealthy regions of China, prenatal genetic testing is already very widely adopted. We argue that the government should actively promote prenatal genetic testing to the poor areas of the country. In fact, the government should prioritize resources first to make prenatal genetic testing a standard routine care with an opt‐out model in these area. Healthcare professions would be required to inform pregnant women about the availability of genetic testing and provide free testing on a routine basis unless the parents choose not to do so. We argue that this proposal will allow parents to make a more informed decision about their reproductive choices. Secondarily, this proposal will attract more healthcare professionals and other healthcare resources to improve the healthcare infrastructures in the less‐developed regions of the country. This will help to reduce the inequity of accessing healthcare services between in different regions of China. We further argue that this policy proposal is not practicing eugenics. 相似文献
57.
The membrane systems of the cardiac muscle cell of Munida tenuimana G. O. Sars are described. The sarcolemma invaginates at the Z level, forming tubules. Narrow tubules branch off in a longitudinal direction from these transverse and radially arranged tubules, forming a narrow transverse collar at the H level where dyadic and triadic junctions are formed with the sarcoplasmic reticulum. 相似文献
58.
59.
A morphological analysis of the Scandinavian mountain endemic Draba cacuminum Elis. Ekman is presented, based on Scandinavian herbarium collections and a population sample from the Finse area, S Norway. It is compared with supposedly close relatives, especially D. norvegica Gunnerus, and is found to be a distinct species with infraspecies variation at two levels. The populations of southern and northern Scandinavia have been separated as subspecies, ssp. cacuminum and ssp. angusticarpa Elven ssp. nov., respectively, and there is also variation within the southern subspecies. A lectotype has been chosen for D. cacuminum , a revised distribution map is presented, and the ecology and phytogeography of the species is discussed. It seems to be a weak competitor, and its present very discontinuous area is assumed to be a remnant of one continuous or more probably two areas (in S Norway and N Scandinavia) in the late Weichselian. 相似文献
60.
The aim of this study was to investigate the feasibility of two detection methods for use in discrimination and sorting of adult Atlantic cod (about 2 kg) in the small scale capture-based aquaculture (CBA). Presently, there is no established method for discrimination of weaned and unweaned cod in CBA. Generally, 60–70% of the wild-caught cod in the CBA are weaned into commercial dry feed. To increase profitability for the fish farmers, unweaned cod must be separated from the stock, meaning the fish must be sorted into two groups – unweaned and weaned from moist feed. The challenges with handling of large numbers of fish in cages, defined the limits of the applied technology. As a result, a working model was established, focusing on implementing different marking materials added to the fish feed, and different technology for detecting the feed presence in the fish gut. X-ray imaging in two modes (planar and dual energy band) and sensitive radio-frequency metal detection were the detection methods that were chosen for the investigations. Both methods were tested in laboratory conditions using dead fish with marked feed inserted into the gut cavity. In particular, the sensitive radio-frequency metal detection method with carbonyl powder showed very promising results in detection of marked feed. Results show also that Dual energy band X-ray imaging may have potential for prediction of fat content in the feed. Based on the investigations it can be concluded that both X-ray imaging and sensitive radio-frequency metal detector technology have the potential for detecting cod having consumed marked feed. These are all technologies that may be adapted to large scale handling of fish from fish cages. Thus, it may be possible to discriminate between unweaned and weaned cod in a large scale grading situation. Based on the results of this study, a suggestion for evaluation of concept for in-situ sorting system is presented. 相似文献