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1.
Genetic diversity among the Newars of Nepal has been studied using Wright's FST and the ratio of observed variance to theoretical variance following Lewontin and Krakauer's 1973 method, based on six genetic characteristics. The gene differentiation among the Newars is only 1.7%. These observations are further corroborated by the results obtained through genetic distance analysis. The average heterozygosity per locus is high (ranging from 35 to 42%) for all the groups. About 95% of total gene diversity exists within the Newar groups, the intergroup components being only about 5%.  相似文献   

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The analytical model of Bongaarts and Potter is employed to compare the proximate determinants of fertility among 3 populations in Nepal's Kathmandu valley. 3 sub-groups are studied: high caste (Brahmin and Chetri) urban residents, high caste urban fringe residents, and low caste untouchables (Sarki). Both survey and anthropological methods are employed. According to the analytical model, the transition in fertility follows 4 phases. The changes in fertility levels from Phase 1 to Phase 4 generally indicate that the transition from natural to controlled fertility is characterized by declines in the proportions of women married and the duration of postpartum infecundability, and a substantial increase in the prevalence and effectiveness of contraceptive practices. The results of this study show that Nepal as a whole is entrenched in Phase 1 of the fertility transition. However, data from the 3 populations reported here clearly indicate that each has begun to experience a demographic transition to different degrees. The Sarkis in this study fall between Phases 2 and 3, as indicated by the total fertility rate (TFR). The rural high castes most closely approximate a population in Phase 3, while urban high castes included in this study are approaching Phase 4. Each of the 3 populations is characterized by a decline in the proportion of women married when compared to all of Nepal. It is also apparent that the relative use-effectiveness of contraceptive methods currently employed is high. Gains in the reduction of fertility, then, will have to be made from increasing and retaining the number of acceptors and in reducing the desired family size of those at reproductive risk.  相似文献   

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Kathmandu Valley, Nepal is undergoing rapid urbanization but its effects on the bird communities have not been reported till date. Kathmandu Valley was categorized into urban, sub-urban and rural to study the impact of urbanization in bird communities. By mobilizing volunteers, we monitored 24 transects each with one km long in summer and winter seasons of 2016. A total of 13,749 individuals of birds belonging to 102 species were recorded. Species richness and diversity of all birds declined from rural to urban areas and showed significant variation along urban–rural gradients. Insectivore was the most species-rich guild while nectarivore the least. The richness of insectivore, frugivore and carnivore guilds showed significant variations along the urban–rural gradients and higher preference towards the rural areas. Similarly, species richness of all birds and richness of insectivore and carnivore guilds showed significant seasonal variation and were higher in the winter season. Our results indicate that richness, diversity and feeding guilds of birds show different response towards the urbanization gradients and seasons. Sub-urban areas can function as bird refugia, however, habitat enrichments (like increasing green spaces, setting up new parks and gardens, plantation of native fruiting trees etc.) are utmost necessary to support the bird communities in urban areas of Kathmandu Valley.  相似文献   

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We studied the influence of site conditions on epiphytic orchids under a subtropical climate in the Kathmandu Valley, Nepal. We analysed 96 systematically distributed grid points situated in Kathmandu Valley across a land-use intensity gradient (national park to urbanised city area). Geographical Information System (GIS) and remote sensing were used for classification of land-use types. We identified 23 species of epiphytic orchids, within 13 genera, from 42 different host tree species. Host preference is obvious for some orchid species (e.g., Dendrobium nobile), with certain tree species (e.g., Schima wallichii, Ficus religiosa) hosting more orchid species than others. The orchid Rhynchostylis retusa was the most common species found on many different host tree species across the land-use intensity gradient. Host species and host bark characteristics (e.g., rugosity, pH and exposure to wind) played a vital role for orchid distribution, with lower abundance in areas of higher impact. Under strong human impact (urban city area), F. religiosa was the dominant host tree, with large individual trees (mean diameter in breast height, dbh?=?1.3?m) providing the habitat for considerable populations of R. retusa individuals. In general, epiphytic orchids were found on larger host trees in urban areas than in areas of lower human impact. We found that some hosts are more likely to harbour orchid species, especially native host species. Older larger trees with rougher bark, low pH, exposed to wind and reduced human impact provided better habitats for orchids. We suggest these characteristics should be considered in urban planning to reduce human impact on the associated orchid epiphytic community.  相似文献   

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1. Diatoms are recognised as indicators in temperate streams, but only recently have assessments begun of their value in indicating stream quality in the tropics and sub‐tropics. Here, we extend previous studies by assessing stream diatom assemblages in relation to water quality and habitat character in the Kathmandu Valley, and in the Middle Hills of Nepal and northern India. We also assessed whether the U.K. Trophic Diatom Index (TDI) was sufficiently portable to reveal pollution in Himalayan rivers. In the more urbanised and highly agricultural Kathmandu Valley, we compared diatom response to water quality classes indicated by a local invertebrate index, the Nepalese Biotic Score (NEPBIOS). 2. Thirty and 53 streams in the Kathmandu Valley (2000) and Middle Hills (1994–96), respectively, were sampled in October and November during stable flows following the monsoon. Diatoms were collected in riffles, water samples taken for chemical analysis, and habitat character of the stream channel, bank and catchment assessed using river habitat surveys. In the Kathmandu Valley, macroinvertebrates were collected by kick‐sampling. 3. In total, 113 diatom taxa were found in the Kathmandu Valley streams and 106 in the Middle Hills. Of 168 taxa recorded, 62 occurred only in the Kathmandu Valley, 56 only in the Middle Hills and 50 were common to both areas. Most taxa found only in the Kathmandu Valley belonged to the genus Navicula while most taxa confined to the Middle Hills were Achnanthes, Fragilaria and Gomphonema. 4. In the Kathmandu Valley, richness and diversity increased significantly with K, Cl, SO4 and NO3, but declined significantly with Al, Fe, surfactants and phenols. Richness here also varied with habitat structure, being lowest in fast flowing, shaded streams with coarse substrata in forested catchments. In all streams combined, richness increased significantly with Si, Na and PO4, but declined significantly with increasing pH, Ca and Mg. 5. Diatom assemblage composition in the Kathmandu Valley strongly reflected water chemistry as revealed by cations (K, Na, Mg, Ca), anions (Cl, SO4), nutrients (NO3, PO4, Si), and also substratum composition, flow character and catchment land use. The commonest taxa in base‐poor forested catchments were Achnanthes siamlinearis, A. subhudsonis, A. undata and an unidentified Gomphonema species; Cocconeis placentula and Navicula minima in agricultural catchments; and Mayamaea atomus var. alcimonica, M. atomus var. permitis, and Nitzschia palea at polluted sites near settlements. Diatom assemblages in none‐agricultural catchments of the Kathmandu Valley and Middle Hills were similar, but they contrasted strongly between urban or agricultural catchments of the Kathmandu Valley and the less intensively farmed catchments of the Middle Hills. 6. In keeping with variations in assemblage composition, most streams in the Kathmandu Valley had higher TDI values (33–87, median = 64) and more pollution tolerant taxa (0–78%, median = 16) than streams in the Middle Hills (25–82, median 45, 0–26%, median = 2). TDI values correlated significantly with measured PO4, Si, and Na concentrations in the Kathmandu Valley, and with Si and Na concentrations in the Middle Hills. There was some consistency between water quality classes revealed by NEPBIOS and diatoms, but also some contrast. Water quality class I–II sites had lower TDI values and were less species rich than water quality II sites, however, there were no significant differences in detrended correspondence analysis (DCA) assemblage scores and relative abundances of pollution tolerant taxa between NEPBIOS classes. 7. While diatoms in the Middle Hills indicate unpolluted or only mildly enriched conditions, they reveal pronounced eutrophication and organic pollution in the densely populated Kathmandu Valley. In addition, diatoms appear to respond to altered habitats in rural agricultural and urban areas. As demands on water resources in this region are likely to increase, we advocate the continued development of diatoms as indicators using methods based on what appear to be consistent responses in the TDI between Europe and the Himalaya.  相似文献   

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This case study illustrates links between problem structuring, multiple epistemologies across nested scales, assessment, and remediation. Cystic echinococcosis is a parasitic disease of people associated with a gastrointestinal tapeworm of dogs. Since it usually cycles between canids and other vertebrates, the parasite is linked to food safety through slaughtering techniques, which in turn are related to changes in the characteristics of the agro-urban ecosystem. These in turn cannot be dealt with without addressing the socioeconomic and cultural aspects of the system, that is, the eco-social narratives which people (including scientists) use to structure their daily lives. A 10-year series of research projects in Nepal demonstrated that post-World War II epidemiological techniques, designed for studying individuals in Western industrialized countries, could identify some risk factors but had a mixed record at achieving solutions which required collective action. Effective solutions were arrived at only after local stakeholders and governance structures were engaged in a process of defining the structure of the problem. Assessment (placing values on scientific measurements) and remediation (acting on those values) require both citizen engagement and an understanding of complex systems. These are synthesized through the creation of culturally acceptable narratives.  相似文献   

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The prevalence of infestation with head lice and body lice, Pediculus spp. (Phthiraptera: Pediculidae) and pubic (crab) lice Pthirus pubis (L.) (Phthiraptera: Pthiridae), was recorded from 484 people in Nepal. The prevalence of head lice varied from 16% in a sample of people aged 10-39 years of age, to 59% in street children. Simultaneous infestations with head and body lice (double infestations) varied from 18% in slum children to 59% in street children.  相似文献   

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Four subtropical mountain lakes in western Nepal were investigated for their plankton content and hydrographical conditions. Phytoplankton species composition, vertical distribution and seasonal variations were studied, and physical (temperature, visibility, electrical conductivity) and chemical (pH-value, alkalinity) properties of the lakes measured. The lakes rank among the subtropical monomictic type with thermal stratification and have a very low electrical conductivity. The phytoplankton (made up of diatom-desmid and dinoflagellate associations) comprised a mixture of species from tropical, Indo-Malayan and temperate regions; species from temperate regions, however, predominated.  相似文献   

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This unmatched case-control study determined the risk factors for neonatal encephalopathy among term infants in Kathmandu, Nepal. Study participants included 131 infants with neonatal encephalopathy born between January 1995 and July 1996, and 635 unmatched infants systematically recruited over 12 months. The prevalence of neonatal encephalopathy was 6.1% per 1000 live births, of which 63% were infants with moderate encephalopathy. Antepartum risk factors included multiple births (odds ratio, OR = 22), primiparity (OR = 2.0), and nonattendance for antenatal care (OR = 2.1). Intrapartum risk factors were particulate meconium (OR = 18), noncephalic presentation (OR = 3.4), prolonged rupture of membranes (OR = 3.8), and other complications. In addition, induction of labor with oxytocin was associated with encephalopathy in 12 of 41 deliveries (OR = 5.7). Overall, 78 affected infants (60%) compared with 36 controls (6%) either had evidence of intrapartum compromise or were born after an intrapartum difficulty likely to result in fetal compromise. Moreover, maternal hemoglobin concentration 8.0 g/dl (OR = 2.5) and thyroid stimulating hormone 5 ml U/l (OR = 2.1) were associated with encephalopathy. Intrapartum risk factors remain important for neonatal encephalopathy in developing countries. There is some evidence of a protective effect from antenatal care. The use of oxytocin in low-income countries where intrapartum monitoring is suboptimal presents a major risk to the fetus. Further studies are required to explore the association between maternal deficiency states and neonatal encephalopathy.  相似文献   

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The primary objective of this report is to use data from a study of infant growth and weaning practices in Kathmandu, Nepal, to investigate universal recommendations about exclusive breast-feeding up to 6 months postpartum. A secondary objective is to demonstrate the complexity of the biocultural nature of infant feeding practices. A sample of 283 children under 5 years of age and their 228 mothers living in a peri-urban district of Kathmandu participated in this study. The children's height/length and weight were measured three times over 9 months. At each session, a demographic, child health and infant feeding survey was administered; between sessions, in-depth interviews were conducted with mothers regarding infant feeding practices. While a few of the infants under 2 months were receiving non-breast milk foods, at 3 months of age half of the sample had been introduced to non-breast milk foods and by 7 months all infants were eating non-breast milk foods. A comparison of growth indices and velocities between exclusively and partially breast-fed infants from birth to 7 months of age shows no evidence for a difference in nutritional status between the two groups. Although there are cultural rules about breast-feeding that vary by ethnic group, all mothers followed a feeding method that depended on their assessment of whether the child was getting enough breast milk. The conclusion is that exclusive breast-feeding up to 6 months may not be appropriate for all infants. In this sample, breast-feeding duration is not shortened by the early introduction of non-breast milk foods, as the median age of breast-feeding cessation is 36 months. One of the main reasons for severance was the onset of another pregnancy. Investigation of infant feeding practices must be contextualized in the local ecology of the population. While cultural beliefs about breast-feeding are relevant, mothers' individual assessments of their children's nutritional needs and demographic events in parents' lives must also be considered.  相似文献   

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