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1.
Jonathan M. Schwartz 《American anthropologist》1997,99(4):870-871
The Macedonian Conflict: Ethnic Nationalism in. Transnational World. Loring M. Danforth. Princeton, NJ: Princeton University Press, 1995. 273 pp. 相似文献
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D. L. VOGELIEN L. G. HICKOK R. M. AUGÉ A. J. W. STODOLA D. HENDRIX 《Plant, cell & environment》1993,16(8):959-966
The stl1 and stl2 mutations confer low and high levels of NaCl tolerance to gametophytes of the fern Ceratopteris richardii, respectively. As an initial characterization of these mutations, the levels of various organic solutes, tissue ion content and water relations were examined in the wild-type and mutant strains in the absence and presence of 60 mol m-3 NaCl stress (a level which results in a 20, 15 and 0% reduction in gametophyte growth in the wild-type, stl1 mutant and stl2 mutant, respectively). All strains exhibited major changes in organic and inorganic solute levels and water relations in response to 60 mol m-3 NaCl stress. Differences in organic solute levels and water relations between the wild-type and mutant strains in the absence and in response to 60 mol m-3 NaCl stress were minimal. Analysis of tissue ion content showed that stl1 was associated with a slight reduction in Na+ accumulation during 60 mol m-3 NaCl stress. stl2 was associated with (1) higher constitutive levels of K+ and (2) continued selective accumulation of K+ and reduced accumulation of Na+ during 60 mol m-3 NaCl stress. A K+/Na+ ratio close to 1 was observed in the wild-type during 60 mol m-3 NaCl stress, while higher ratios were detected in stl1 and stl2 (1·7 and 4·0, respectively). The findings of this study suggest that the tolerance imparted by stl1 and stl2 is associated with altered ion accumulation during NaCl stress, rather than an enhanced ability to accumulate organic solutes to be used for osmotic adjustment of the cytoplasm. 相似文献
3.
Begoña Aretxaga 《American anthropologist》1997,99(2):420-421
The Politics of Difference: Ethnic Premises in. World of Power. Edwin N. Wilmsen and Patrick McAllister. eds. Chicago: University of Chicago Press, 1996. 210 pp. 相似文献
4.
The involvement of a vanadate-sensitive ATPase in plasma membranes of a salt tolerant cyanobacterium
Rachel Gabbay-Azaria Uri Pick Gozal Ben-Hayyim Elisha Tel-Or 《Physiologia plantarum》1994,90(4):692-698
Plasma membranes of the marine cyanobacterium Spirulina subsalsa were tested for ATPase activity, and for involvement in salt stress. Transition of cells from saline to hypersaline medium enhances the respiratory activity associated with extrusion of Na+ and Cl− , and persisting salt stress induces synthesis of respiratory enzymes in the plasma membranes. The membranes possess an ATPase, specific for ATP and Mg2+ and sensitive to orthovanadate and dicyclohexylcarbodiimide. Immunoblot analysis of plasma membrane polypeptides from Spirulina subsalsa with anti- Arabidopsis H+ -ATPase serum identified a single polypeptide of 100 kDa, which cross-reacted with the antibodies. An unusual feature of this ATPase is a specific stimulation by Na+ ions. Prolonged adaptation of S. subsals cells to hypersaline conditions induced an increase in ATPase activity in subsequent plasma membrane preparations, as well as a higher content of the 100 kDa polypeptide. It is suggested that the ATPase investigated is an H+ -pump, which is involved in extrusion of Na+ and in conferring resistance to salt stress. 相似文献
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Patterns of vascular plant diversity in Denmark are examined, based on the most recently published Danish Flora. The highest diversity is found on the major isles of Sjælland, Møn, Falster and Bornholm, but many rare taxa occur in Jylland. Two different cluster analyses suggest a division of Denmark into six phytogeographical regions, which only partly supports earlier, more subjective divisions of Denmark. Our results suggest that north- and northwestern Jylland and the isles of Læsø and Anholt belong to the boreo-nemoral phytogeographical region, due to their high number of northern taxa, which clearly differentiate them from the rest of Denmark, despite the lack of typical boreo-nemoral tree species, such as Pinus sylvestris.Because the tree component of vegetation often has been changed by man, the classical division of Scandinavia based on a few woody species is inappropriate. We conclude that tree-species oriented approaches are invalid for phytogeographical classifications.Classification, based on the whole flora, and if possible also involving environmental information, is likely to be more successful and should be addressed in future phytogeographical studies. 相似文献
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Soil salinity is a major abiotic stress in plant agriculture strongly, influencing plant productivity world-wide. Classical breeding for salt tolerance in crop plants has been attempted to improve field performance without success. Therefore, an alternative strategy is to generate salt tolerant plants through genetic engineering. Several species and experimental approaches have been used in order to identify those genes that are important for salt tolerance. Due to high level of salt tolerance, halophytes are good candidates to identify salt tolerance genes. However, other species such as yeast and glycophytes have also been employed. Three approaches are commonly used to identify genes important for salt tolerance. The first approach is to identify genes involved in processes known to be critical for salt tolerance (osmolyte synthesis, ion homeostasis, etc.). The second approach is to identify genes whose expression is regulated by salt stress. This is relatively simply and applicable to any plant species. Genetic amenability of some species allows the third approach, which consists in the identification of salt tolerance determinants based on functionality. At the moment, there is a large number of reports in the literature claiming that plants with increased salt tolerance have been obtained. The main problem is that different plant species, stage of development, organs, promoters and salt conditions used it is difficult to compare the degree of salt tolerance conferred by different genes. In this review, we discuss progress made towards understanding the molecular elements involved in salt stress responses that have been used in transgenic approaches to improve salt tolerance. 相似文献
9.
Sodium relations in Chenopodiaceae: a comparative approach 总被引:2,自引:0,他引:2
Sodium relations of 15 species of Chenopodiaceae were studied in seedlings grown on quartz sand at 10 mol m?3 of sodium and potassium. Uptake of sodium and potassium into whole plants and shoots was followed over 2 weeks. High alkali ion uptake rates were found in all species. The apparent selectivity of alkali ion uptake showed a continuous variation between species, from nearly perfect sodium exclusion to negligible cation selection. K/Na ratios above 6 were found in the shoots of eight species. For most of these plants above ground sodium concentrations were highest in the hypocotyls. However, in Chenopodium hybridum (shoot K/Na = 10) and C. urbicum (shoot K/Na = 17) above ground sodium concentrations were lowest in hypocotyls and highest in leaves, as in those species accumulating larger amounts of sodium. These differences are discussed with respect to the underlying mechanisms of ion regulation. 相似文献
10.
M Harrison A Kilby J A Walker-Smith N E France C B Wood 《BMJ (Clinical research ed.)》1976,1(6024):1501-1504
Twenty-five children with cows'' milk protein intolerance were studied. Twenty had presented with an illness clinically indistinguishable from infantile gastroenteritis; an enteropathogenic Escherichia coli was isolated from the stools in two children, and in six another member of the family simultaneously developed acute diarrhoea and vomiting. Twenty-three children had lactose intolerance secondary to cows'' milk protein intolerance. Eight out of 20 children were found to be partially IgA deficient. An acute attack of gastroenteritis, in damaging the small mucosa, may act as a triggering mechanism in cows'' milk protein intolerance, and a deficiency in IgA may be a predisposing factor in so far as it allows the patient to become sensitised to foreign protein. 相似文献
11.
Hao WY Zhang LF Wu XY 《Journal of gravitational physiology : a journal of the International Society for Gravitational Physiology》2000,7(2):P151-P152
Orthostatic intolerance (OI) following exposure to microgravity or head-down bed rest is frequently observed and is thought to be multifactorial origin. Although hypovolemia is considered as the primary cause of OI, the role played by other factors, such as the lowered vasoconstrictor responsiveness (VCR) of resistance vessels, the enhanced vasoconstriction response of cerebral vessels, and the depressed myocardial contractility need to be elucidated. It is difficult to assess experimentally how each of these changes would affect orthostatic tolerance and how these factors interact with each other. An alternative approach is to conduct simulation studies by use of mathematical models of cardiovascular system (CVS) capable of simulating the CVS response to orthostatic stress. This presentation describes the construction of the model used, and presents the preliminary simulation results illustrating the effects of varying individually the level of hypovolemia, VCR of the resistance vessels in lower limbs and abdominal viscera, VCR of the brain vessels or myocardial contractility on responses to orthostatic stress. The ultimate goal of our work was to integrate the new experimental findings and to simulate the complexity to get a thorough understanding of the mechanism of postflight cardiovascular dysfunction and orthostatic intolerance. 相似文献
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Background
Tuberculosis is a leading cause of death in people living with HIV (PLWH). We conducted a meta analysis to assess the effect of tuberculosis on mortality in people living with HIV.Methods
Meta-analysis of cohort studies assessing the effect of tuberculosis on mortality in PLWH. To identify eligible studies we systematically searched electronic databases (until December 2008), performed manual searches of citations from relevant articles, and reviewed conference proceedings. Multivariate hazard ratios (HR) of mortality in PLWH with and without tuberculosis, estimated in individual cohort studies, were pooled using random effect weighting according to “Der Simonian Laird method” if the p-value of the heterogeneity test was <0.05.Results
Fifteen cohort studies were systematically retrieved. Pooled overall analysis of these 15 studies estimating the effect of tuberculosis on mortality in PLWH showed a Hazard Ratio (HR) of 1.8 (95% confidence interval (CI): 1.4–2.3). Subanalysis of 8 studies in which the cohort was not exposed to highly active antiretroviral therapy (HAART) showed an HR of 2.6 (95% CI: 1.8–3.6). Subanalysis of 6 studies showed that tuberculosis did not show an effect on mortality in PLWH exposed to HAART: HR 1.1 (95% CI: 0.9–1.3).Conclusion
These results provide an indication of the magnitude of benefit to an individual that could have been expected if tuberculosis had been prevented. It emphasizes the need for additional studies assessing the effect of preventing tuberculosis or early diagnosis and treatment of tuberculosis in PLWH on reducing mortality. Furthermore, the results of the subgroup analyses in cohorts largely exposed to HAART provide additional support to WHO''s revised guidelines, which include promoting the initiation of HAART for PLWH co-infected with tuberculosis. The causal effect of tuberculosis on mortality in PLWH exposed to HAART needs to be further evaluated once the results of more cohort studies become available. 相似文献14.
In European floras Cirsium palustre (L.) Scop. usually is classified as a biennial and monocarpic species. The value of this classification was examined in a population growing in a spring area in Jutland, Denmark. It was possible to describe five ontogenetic states, i.e. life-states, in the population, the seed state excluded. Each Kate normally lasted for one growing season. Therefore the flowering state was generally not reached until in the fifth growing season. Observation on mortality revealed that seedlings were exposed to an extremely high death risk. However, in the other vegetative life states the death risk was rather low and constant. 相似文献
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Feeding a world of 10 billion people: The miracle ahead 总被引:1,自引:0,他引:1
Norman E. Borlaug 《In vitro cellular & developmental biology. Plant》2002,38(2):221-228
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Interactions of an acid tolerant strain of phosphate solubilizing bacteria with a few acid tolerant crops 总被引:4,自引:0,他引:4
Phosphate solubilizing bacteria (PSB) were isolated from sixty soil samples of various soil classes and cropping histories in Himalayan regions of Uttar Pradesh, India by enrichment culture techniques. Phosphate solubilization and acid tolerance of each strain was estimated. A strain (PAS-2) isolated froma pasture and waste land of pH 4.8, organic matter 2.6% available N 265kg ha-1, available P2O5(Bray's II) 2.3kg ha-1 and available K2O 353 kg ha-1 had the highest P-solubilization (45 µg P per mL per day) and also highest acid tolerance rating 42. The strain was identified as Bacillus sp. Seed inoculation of this bacterial strain resulted in significant increases in grain and vegetative yield of fingermillet (Elosine coracana), maize (Zea mays), amaranth (Amaranthus hypochondriacus), buckwheat (Fagopyrium esculentum), frenchbean (Phaseolus vulgaris) with or without added P sources. The significant grain yield (quintol ha-1) with phosphate and seed inoculation ranged from 33.85 in maize, 26.33 in frenchbean, 22.41 in buckwheat, 20.71 in amaranth and 19.19 in fingermillet as compared to controls. The highest response was observed with frenchbean followed by fingermillet, buckwheat, amaranth and maize. Phosphate use efficiency was highest in frenchbean followed by maize and lowest and almost at par in buckwheat, amaranth and fingermillet. Available phosphate was also highest in frenchbean cultivated plot followed by amaranth, fingermillet, buckwheat and maize. The MPN count of phosphate solubilizing bacteria were also influenced by seed inoculation of strain PAS-2. Frenchbean exerted greaterrhizosphere effect followed by pseudocereals and cereals. Likewise, phosphate nutrition of crops were also improved through seed inoculation irrespective of added P sources. The study thus demonstrated that selection of efficient strain of PSB from acid soil and its seed inoculation in selected crop genotype is beneficial in boosting up crop yield in low productive hill soil. Seed inoculation also created greater rhizosphere effect over uninoculation which improved P-nutrition of crops and also available soil P. 相似文献
18.
Lebech AM 《Bioethics》1997,11(3-4):336-340
The practice of informed consent in biomedicine is so widely spread that it must be considered the most important principle within bioethics, and the most universally appealed to within recent legislation. There seems to be a consensus as to its value in research on autonomous persons, but also a problem concerning its application when dealing with people having a serious mental, social or even physical disability.
Within the field of artificial procreation there are even more problems. Informed written consent is often demanded from anonymous donors of gametes in order to ensure their consent to the legal and moral consequences of their anonymity. The child resulting from the artificial procreation, on the contrary, cannot consent to, nor be informed before being conceived, of the secrecy laid on the identity of its genetic parents. Some countries resolve this problem by allowing the children, when they reach their majority, to obtain some information pertaining to the health or the identity of their genetic parents.
This presents ethical problems. It can be argued that the anonymity of the parents chiefly affects the children, so that an agreement on this point among parents, doctors and others must be regarded as invalid. The paper will argue that a law ensuring the complete anonymity of the parents is disregarding the informed consent and the interests of the children resulting from artificial procreation, and is thus doing more damage to society than good. 相似文献
Within the field of artificial procreation there are even more problems. Informed written consent is often demanded from anonymous donors of gametes in order to ensure their consent to the legal and moral consequences of their anonymity. The child resulting from the artificial procreation, on the contrary, cannot consent to, nor be informed before being conceived, of the secrecy laid on the identity of its genetic parents. Some countries resolve this problem by allowing the children, when they reach their majority, to obtain some information pertaining to the health or the identity of their genetic parents.
This presents ethical problems. It can be argued that the anonymity of the parents chiefly affects the children, so that an agreement on this point among parents, doctors and others must be regarded as invalid. The paper will argue that a law ensuring the complete anonymity of the parents is disregarding the informed consent and the interests of the children resulting from artificial procreation, and is thus doing more damage to society than good. 相似文献
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Chromosomal abnormalities among offspring of childhood-cancer survivors in Denmark: a population-based study
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Winther JF Boice JD Mulvihill JJ Stovall M Frederiksen K Tawn EJ Olsen JH 《American journal of human genetics》2004,74(6):1282-1285
Ionizing radiation and many cancer drugs have the potential to produce germ-cell mutations that might lead to genetic disease in the next generation. In a population-based study, we identified, from records in the Danish Cancer Registry, 4,676 children treated for cancer. Their 6,441 siblings provided a comparison cohort. The results of a search of the Central Population Register identified 2,630 live-born offspring of the survivors and 5,504 live-born offspring of their siblings. The occurrence of abnormal karyotypes diagnosed in these offspring and also in any pregnancies terminated following prenatal diagnosis of a chromosome abnormality was determined from the Danish Cytogenetic Registry. After exclusion of hereditary cases and inclusion of the prenatal cases, after correction for expected viability, the adjusted proportion of live-born children in survivor families with abnormal karyotypes (5.5/2,631.5 [0.21%]) was the same as that among the comparison sibling families (11.8/5,505.8 [0.21%]). There were no significant differences in the occurrence of Down syndrome (relative risk [RR]=1.07; 95% CI 0.16-5.47) or Turner syndrome (RR=1.32; 95% CI 0.17-7.96) among the children of cancer survivors, compared with the children of their siblings. These reassuring results are of importance to the survivors, to their families, and to genetic counselors. 相似文献