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71.
Biodiversity and ecosystem services: a multilayered relationship 总被引:2,自引:0,他引:2
The relationship between biodiversity and the rapidly expanding research and policy field of ecosystem services is confused and is damaging efforts to create coherent policy. Using the widely accepted Convention on Biological Diversity definition of biodiversity and work for the U.K. National Ecosystem Assessment we show that biodiversity has key roles at all levels of the ecosystem service hierarchy: as a regulator of underpinning ecosystem processes, as a final ecosystem service and as a good that is subject to valuation, whether economic or otherwise. Ecosystem science and practice has not yet absorbed the lessons of this complex relationship, which suggests an urgent need to develop the interdisciplinary science of ecosystem management bringing together ecologists, conservation biologists, resource economists and others. 相似文献
72.
Many studies show that the extended human family can be helpful in raising offspring, with maternal grandmothers, in particular, improving offspring survival. However, less attention has been given to competition between female kin and co-residents. It has been argued that reproductive conflict between generations explains the evolution of menopause in cooperatively breeding species where females disperse, and that older females are related to the offspring of younger females through their sons, whereas younger, incoming females are unrelated to older females. This means the pattern of help will be asymmetric, so older females lose in reproductive conflict and become 'sterile helpers'. Here, we seek evidence for female reproductive competition using longitudinal demographic data from a rural Gambian population, and examine when women are helping or harming each other's reproductive success. We find that older women benefit and younger women suffer costs of reproductive competition with women in their compound. But the opposite is found for mothers and daughters; if mother and daughter's reproductive spans overlap, the older woman reduces her reproduction if the younger woman (daughter) reproduces, whereas daughters' fertility is unaffected by their mothers' reproduction. Married daughters are not generally co-resident with their mothers, so we find not only competition effects with co-resident females, but also with daughters who have dispersed. Dispersal varies across human societies, but our results suggest reproductive conflict could be influencing reproductive scheduling whatever the dispersal pattern. A cultural norm of late male marriage reduces paternal grandmother/daughter-in-law reproductive overlap almost to zero in this population. We argue that cultural norms surrounding residence and marriage are themselves cultural adaptations to reduce reproductive conflict between generations in human families. 相似文献
73.
Modern industrialized populations lack the strong positive correlations between wealth and reproductive success that characterize
most traditional societies. While modernization has brought about substantial increases in personal wealth, fertility in many
developed countries has plummeted to the lowest levels in recorded human history. These phenomena contradict evolutionary
and economic models of the family that assume increasing wealth reduces resource competition between offspring, favoring high
fertility norms. Here, we review the hypothesis that cultural modernization may in fact establish unusually intense reproductive
trade-offs in wealthy relative to impoverished strata, favoring low fertility. We test this premise with British longitudinal
data (the Avon Longitudinal Study of Parents and Children), exploring maternal self-perceptions of economic hardship in relation
to increasing family size and actual socioeconomic status. Low-income and low-education-level mothers perceived the greatest
economic costs associated with raising two versus one offspring. However, for all further increases to family size, reproduction
appears most expensive for relatively wealthy and well-educated mothers. We discuss our results and review current literature
on the long-term consequences of resource dilution in modern families. 相似文献
74.
Jessica Bovill Anke Lehmensiek Mark W. Sutherland Greg J. Platz Terry Usher Jerome Franckowiak Emma Mace 《Molecular breeding : new strategies in plant improvement》2010,26(4):653-666
Bipolaris sorokiniana (teleomorph: Cochliobolus sativus) is the fungal pathogen responsible for spot blotch in barley (Hordeum vulgare L.) and occurs worldwide in warmer, humid growing conditions. Current Australian barley varieties are largely susceptible
to this disease and attempts are being made to introduce sources of resistance from North America. In this study we have compared
chromosomal locations of spot blotch resistance reactions in four North American two-rowed barley lines; the North Dakota
lines ND11231-12 and ND11231-11 and the Canadian lines TR251 and WPG8412-9-2-1. Diversity arrays technology-based PCR, expressed
sequence tag and SSR markers have been mapped across four populations derived from crosses between susceptible parental lines
and these four resistant parents to determine the location of resistance loci. Quantitative trait loci (QTL) conferring resistance
to spot blotch in adult plants (APR) were detected on chromosomes 3HS and 7HS. In contrast, seedling resistance (SLR) was
controlled solely by a locus on chromosome 7HS. The phenotypic variance explained by the APR QTL on 3HS was between 16 and
25% and the phenotypic variance explained by the 7HS APR QTL was between 8 and 42% across the four populations. The SLR QTL
on 7HS explained between 52 and 64% of the phenotypic variance. An examination of the pedigrees of these resistance sources
supports the common identity of resistance in these lines and indicates that only a limited number of major resistance loci
are available in current two-rowed germplasm. 相似文献
75.
Steens SC Bosma GP Steup-Beekman GM le Cessie S Huizinga TW van Buchem MA 《Arthritis research & therapy》2006,8(2):R38-7
The pathogenetic role of anticardiolipin antibodies (aCLs) in patients with neuropsychiatric systemic lupus erythematosus
(NPSLE) without cerebral infarcts remains elusive. Magnetization transfer imaging (MTI) has proved to be a sensitive tool
for detecting diffuse microscopic brain damage in NPSLE patients. In this study we examined the correlation between grey and
white matter magnetization transfer ratio (MTR) parameters and the presence of IgM and IgG aCLs and lupus anticoagulant in
18 patients with systemic lupus erythematosus and a history of NPSLE but without cerebral infarcts on conventional magnetic
resonance imaging. Lower grey matter mean MTR (P < 0.05), white matter mean MTR (P < 0.05), white matter peak location (P < 0.05) and grey matter peak location (trend toward statistical significance) were observed in IgM aCL-positive patients
than in IgM aCL-negative patients. No significant differences were found in MTR histogram parameters with respect to IgG aCL
and lupus anticoagulant status, nor with respect to anti-dsDNA or anti-ENA (extractable nuclear antigen) status. This is the
first report of an association between the presence of aCLs and cerebral damage in grey and white matter in NPSLE. Our findings
suggest that aCLs are associated with diffuse brain involvement in NPSLE patients. 相似文献
76.
77.
The hypothesis that measures of sub-adult mortality rates in natural fertility populations are associated with subsistence practices in a selected cross-cultural sample (n = 39) was tested. After controlling for both distance from the equator and the general likelihood of cultural similarities between genetically closely related cultures using phylogenetic comparative methods, it was found that dependence on extractive modes of subsistence (hunting, gathering and fishing) was a significant positive correlated of total child mortality (15q0). Both increases in dependence on foraging and permanent settlement were associated with increases in child mortality between pairs of historically related cultures. The results indicated little association between infant mortality (1q0) and either dependence on foraging or settlement. 相似文献
78.
The eutH gene is part of an operon that allows Salmonella enterica to use ethanolamine as a sole source of nitrogen, carbon, and energy. Although the sequence of EutH suggests a role in transport, eutH mutants use ethanolamine normally under standard conditions (pH 7.0). These mutants fail to use ethanolamine at a low pH. Evidence is presented that protonated ethanolamine (Eth0) does not enter cells, while uncharged ethanolamine (Eth0) diffuses freely across the membrane. The external concentration of Eth0 varies with the pH (pK=9.5). At pH 7.0, the standard ethanolamine concentration (41 mM) provides enough Eth0 for an influx rate that can support growth with or without EutH. When a lowered pH and/or ethanolamine concentration reduced the Eth0 concentration below 25 microM, EutH was needed to facilitate diffusion. EutH+ cells grew normally at Eth0 concentrations above 3 microM, close to the Km (9 microM) of the first degradative enzyme, ethanolamine ammonia lyase. It is suggested that EutH facilitates diffusion of Eth0. As predicted for a transporter, EutH contributed to the toxicity of ethanolamine seen under some conditions; furthermore, fusion of EutH to fluorescent Yfp protein provided evidence that EutH is a membrane protein. 相似文献
79.
Cousin E Genin E Mace S Ricard S Chansac C del Zompo M Deleuze JF 《Human heredity》2003,56(4):151-159
OBJECTIVE: When numerous single nucleotide polymorphisms (SNPs) have been identified in a candidate gene, a relevant and still unanswered question is to determine how many and which of these SNPs should be optimally tested to detect an association with the disease. Testing them all is expensive and often unnecessary. Alleles at different SNPs may be associated in the population because of the existence of linkage disequilibrium, so that knowing the alleles carried at one SNP could provide exact or partial knowledge of alleles carried at a second SNP. We present here a method to select the most appropriate subset of SNPs in a candidate gene based on the pairwise linkage disequilibrium between the different SNPs. METHOD: The best subset is identified through power computations performed under different genetic models, assuming that one of the SNPs identified is the disease susceptibility variant. RESULTS: We applied the method on two data sets, an empirical study of the APOE gene region and a simulated study concerning one of the major genes (MG1) from the Genetic Analysis Workshop 12. For these two genes, the sets of SNPs selected were compared to the ones obtained using two other methods that need the reconstruction of multilocus haplotypes in order to identify haplotype-tag SNPs (htSNPs). We showed that with both data sets, our method performed better than the other selection methods. 相似文献
80.
In this article we present the first analysis of parentage and relatedness in a natural vertebrate population, using Intersimple Sequence Repeat (ISSR) markers. Thus, 28 ISSR markers were used in a study of a sex-role reversed, simultaneously polyandrous shorebird from northeastern Australia, the comb-crested jacana (Irediparra gallinacea). Assessment of parentage was based on comparison of field observations, novel bands, individual-specific bands found in 7/9 males and 4/6 females, and a 99% CI exclusion criteria. Integrating results from these approaches resulted in confirmation of paternity in all 36 chicks. In only one case (2.8% of chicks) was a co-mate assigned paternity. Thus, comb-crested jacanas appear to be genetically monogamous. These results showed resemblance to sequentially polyandrous birds but differed from the simultaneously polyandrous wattled jacana ( Jacana jacana; Emlen et al. 1998). A significant relationship between relatedness and ISSR similarity resulted in recognition that 14/15 adults sampled may be related to at least one other adult by 0.25 or more. Lack of dispersal may be explained by physical limitations and adequate regional habitat. ISSRs proved to be simple and helpful in resolving these issues. 相似文献