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951.
Habitat fragmentation has major negative impacts on wildlife populations, and the connectivity could reduce these negative impacts. This study was conducted to assess habitat suitability and structural connectivity of the Persian leopard along the Iran–Iraq border (i.e., the Zagros Mountains) and compare the situation of identified core habitats and connectivity with existing conservation areas (CAs). An ensemble modeling approach resulting from five models was used to predict habitat suitability. To identify core habitats and corridors along the Iran–Iraq border, factorial least‐cost path analyses were applied. The results revealed that topographic roughness, distance to CAs, annual precipitation, vegetation/cropland density, and distance to rivers were the most influential variables for predicting the occurrence of the Persian leopard in the study area. By an estimated dispersal distance of 82 km (suggested by previous studies), three core habitats were identified (two cores in Iran and one core in Iraq). The largest cores were located in the south and the center of the study area, which had the highest connectivity priorities. The connectivity from these cores was maintained to the core within the Iraqi side. Only about one‐fifth of detected core habitats and relative corridors were protected by CAs in the study area. Detected core habitats and connectivity areas in this study could be an appropriate road map to accomplish the CAs network along the Iran–Iraq border regarding Persian leopard conservation. Establishing transboundary CAs, particularly in the core habitat located in the center of the study area, is strongly recommended to conserve existing large carnivores, including the Persian leopard.  相似文献   
952.
European eels Anguilla anguilla from freshwater lakes in Lithuania had slower growth rates and lower backcalculated total lengths ( L T) than those from lagoons and coastal waters, but no significant differences were found among fish with different migratory histories or between naturally recruited and stocked fish except a higher L T at age of stocked European eels at ages 5 to 8 years. The asymptotic L T did not differ among habitats or migratory histories, but the stocked eels in the lakes had smaller K (coefficient from the von Bertalanffy growth function) than did the both naturally recruited and stocked eels in the lagoon and coastal waters. The growth rate of European eels in Lithuania might be influenced mainly by different habitats rather than different migratory histories and stocking. The lower L T at age of naturally recruited fish at ages 5–8 years compared to stocked fish might result from the extra energy costs entailed in migration from the Atlantic and across the Baltic Sea.  相似文献   
953.
Restriction endonuclease analyses of DNA from one Black GA-HPFH homozygote and four Black and one Indian GA-HPFH heterozygotes have identified three different HPFH types which are the result of large deletions including the and genes. Two of the types are comparable to those characterized previously, but the third, which is present in the Indian heterozygote, shows a distinct difference in the size of the deletion. The 5 end point of the deletion in this type III GA-HPFH extends 0.5–1.0 kb beyond the 5 end point of one of the Black types of HPFH (type I). Each of the three types is associated with a distinct ratio between the G and the A chains, an observation supported by family data. The highest ratio is found in the heterozygote with the Indian type III GA-HPFH, with 69.3% G chains, while the averages for the other types were 50.7% G (type I) and 32.3% G (type II).This research was supported in part by USPHS Research Grants HLB-05168 and HLB-15158 and by designated research funds of the Veterans Administration. This is Contribution 0764 of the Department of Cell and Molecular Biology, Medical College of Georgia, Augusta, Georgia 30912. P. K. Sukumaran was on leave from the Bai Jerbai Wadia Hospital for Children, Parel, Bombay, India.  相似文献   
954.
Synopsis Prejuvenile red hake, Urophycis chuss, that had reached the developmental interval where they normally descend from the planktonic to the benthic environment, were tested for their responses to experimental thermoclines. Laboratory thermoclines were created that simulated natural field conditions of late summer/ early fall (20°C at the surface and 10°C at the bottom). Prejuveniles did not descend immediately through the thermocline; rather, they remained in the water column at temperatures above 15°C. Results indicated that fish in the sea that do eventually reach the bottom despite the presence of a thermocline, must undergo an acclimation period while descending through the thermocline. The timing of prejuvenile descent may depend on a variety of factors including optimal growth conditions, susceptibility to predation, and competition for resources.  相似文献   
955.
ABSTRACT.
  • 1 Once pupal diapause had been terminated, over-wintering cabbage root fly (Delia radicum (L.)) pupae from Wellesbourne required a further 14 days at 20°C for most of the flies to emerge.
  • 2 There were considerable variations in the rates of fly emergence from thirteen populations of cabbage root fly pupae collected between latitudes 50° 42′ and 54° 59′ in England and Wales. These thirteen populations could be grouped into early-, intermediate- and late-emerging types. In the early-emerging type, flies emerged within 14 days at 20°C whereas in the late-emerging type emergence was protracted and was completed only after 100 days at 20°C in one population from Halsall, Lancashire. In the intermediateemerging type, approximately two-thirds of the flies emerged within 14 days at 20° C, the remainder taking considerably longer.
  • 3 The intermediate-emerging types could be just mixtures of the early- and late-emerging types.
  • 4 Subjecting pupae to diapause-breaking temperatures (4°C) for up to 1 year failed to shorten the time to subsequent fly emergence in any of the populations.
  • 5 Populations of early, intermediate- and late-emerging fies could be selected from a parental population, heterogeneous with respect to emergence, within one generation.
  • 6 The type of emergence that occurred in a locality was not correlated with latitude.
  • 7 Any models developed for forecasting the most appropriate time to apply insecticide in a locality will have to include information about the emergence pattern of the fly population in that locality.
  相似文献   
956.
Summary Several null models are proposed for testing whether size or habitat differences in West IndianAnolis lizards are greater than expected by chance. The models differ primarily in choice of the pool from which species are sampled to form random communities. Regardless of choice of pool, size differences in the Lesser Antilles are greater than null models predict; the pool using species on the known source (Puerto Rico) gives a greater variance in ratios but about the same mean ratio (for males), or a greater mean ratio (for females), compared with the pool composed of species on the islands being tested (the Stronget al., 1979, Galápagos procedure). On satellite islands of the Greater Antilles, sizes do not differ more than expected from null models. Pools composed of mainland-source species give null communities with more small or more large ratios than those composed of island species, depending upon whether four-species islands are included or excluded, respectively. Colwell and Winkler's unmodified Narcissus hypothesis is contradicted by these results in procedures where species not likely to be able to occur on small islands are included in the species pool. Using the most biologically reasonable, but not other, choices of source pool, species on satellite islands of the Greater Antilles differ more in structural habitat then expected by chance. In contrast to some of the results on size, here mainland-source pools are more likely to produce a statistically significant difference between real and random communities, as predicted by the Narcissus hypothesis. However, exclusion of structural habitat categories not found on satellite islands is necessary to achieve this significance.  相似文献   
957.
The study is focused on patterns of daily deaths in Shanghai for the period from 1 May 1979 to 30 April 1980. From May to September the deaths in all age groups are lower, but increase gradually from October and reach to a peak in February. This confirms results found in other countries, namely the death rate is increased in winter. The peak for the population aged over 70 is the highest of the three different age groups. Correlation analyses were carried out on three temperature parameters (daily minimum, maximum and mean temperatures) and six categories of death (heart disease, coronary heart disease, cerebrovascular disease, cancer, respiratory disease and total deaths). The results reveal that the average daily temperature is very significant for the six categories of death. There are three correlations: straight line relationship, parabolic relationship and exponential relationship. These different types arise from the different morbidity rates. Death from the different disease is also increased during days when the daily maximum temperature is over 35° C or the daily minimum temperature is below 0°C. This shows, in general, that days of extreme temperature lead to an increase in the death rate.  相似文献   
958.
The cross-reactivity of diverse monoclonal antibodies against phytochrome from Zea and Avena was tested by enzyme-linked immunosorbentassay (ELISA) and by immunoblotting. About 40 antibodies were selected by means of nondenatured phytochrome; all of them reacted with sodium dodecyl sulfate denatured homologous antigen on immunoblots. The epitopes for 14 antibodies (4 raised against Avena and 10 against Zea phytochrome) were localized in 6 regions of the phytochrome molecule by means of Western blot analysis of proteolytic fragments of known localization. Results of studies on the inhibition of antibody binding by other antibodies were largely compatible with these latter findings. Except in a few cases, inhibition occurred when antibodies were located on the same or a closely adjacent region. As demonstrated by 16 species, cross-reactivity with phytochromes from other Poaceae was high. Greater losses in cross-reactivity were observed only with antibodies recognizing an epitope in the vicinity of the carboxyl terminus of 118-kg · mol-1 phytochrome. Cross-reactivity with phytochrome from dicotyledons was restricted to a few antibodies. However, phytochrome(s) from plants illuminated for 24 h or more could be detected. One of the antibodies that recognized phytochrome from dicotyledons was also found to recognize phytochrome or a protein of 120–125 kg·mol-1 from several ferns, a liverwort and mosses. This antibody (Z-3B1), which was localized within a 23.5-kg·mol-1 section of Avena phytochrome (Grimm et al., 1986, Z. Naturforsch. 41c, 993), seems to be the first antibody raised against phytochrome from a monocotyledon with such a wide range of reactivity. Even though epitopes were recognized on different phytochromes, the strength of antibody binding indicated that these epitopes are not necessarily wholly identical.Abbreviations ELISA enzyme-linked immunosorbent assay - McAb monoclonal antibody - PBS phosphate-buffered saline - Pfr (Pr) far-red-absorbing (red-absorbing) form of phytochrome - SDS-PAGE sodium dodecyl sulfate-polyacrylamide gel electrophoresis  相似文献   
959.
Early conservation centred on legislation to prevent species declines. It now includes habitat conseivation, through the establishment of reserves and land management practices in the wider countryside. This need for a broader approach is increasingly acknowledged and presents great opportunities.
Bird enthusiasts, for obvious reasons, have been in the forefront of conservation. This interest continues nationally and internationally.  相似文献   
960.
The utility of artificial habitats as tools in benthic studies was assessed by comparing the faunas associated with natural and artificial plants in a Japanese Sargassum bed. The 35 most common epifaunal species collected were all found to associate with both artificial and natural habitats, however, the abundances of species varied considerably between habitats. Colonization of artificial habitats was most rapid between 8 and 24 days after being placed in the field. This increased rate of colonization at intermediate time periods possibly reflected increasing attractiveness of habitats as a periphytic coating developed after the first week. Artificial habitats preconditioned in a sunlit environment to possess a layer of epiphytic algae attracted much higher numbers of epifaunal animals than habitats placed in a darkened but otherwise similar preconditioning environment. Epifaunal species appear to be attracted to artificial substrata, and presumably also natural habitats, largely because of associated diatoms and epiphytic plants.  相似文献   
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