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11.
The impact of mid-century climatic changes on crop productivity of winter wheat, maize, potato and sugar beet was assessed for a temperate maritime climate in the Flemish Region, Belgium. Climatic projections of multiple regional and global climate models (RCMs from the EU-ENSEMBLES project and GCMs from the Coupled Model Intercomparison Project phase 3) were stochastically downscaled by the LARS-WG weather generator for use in the crop models AquaCrop and Sirius. Primarily positive effects on mean yield were simulated. Crops benefitted from elevated CO2, and from more radiation interception if the cropping period was adapted in response to higher temperatures. However, increased productivity was linked with increased susceptibility to water stress and greater inter-annual yield variability, particularly with adapted management. Impacts differed among and within ensembles of climate models, and among crops and environments. Although RCMs may be more suitable for local impact assessments than GCMs, inter-ensemble differences and contingent wider ranges of impacts with GCM projections found in this study indicate that applying RCMs driven by a limited number of GCMs alone would not give the full range of possible impacts. Further, this study suggests that the simulated intermodel variation can be larger than spatial variation within the region. These findings advocate the use of both GCM and RCM ensembles in assessments where temperature and precipitation are central, such as for crop production.  相似文献   
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Grassland re-seeding or land-use change requires ploughing, which may enhance carbon dioxide (CO2) emissions from soil. This study observed the short to intermediate-term (37 days) effects of ploughing on CO2 emissions from poorly drained grassland using automated soil respiration chambers. Immediately after ploughing, a brief peak in CO2 emissions from soil occurred with a maximum observed flux of 6.91 g CO2 m−2 h−1. Contradictory to other reported results, ecosystem respiration after ploughing was lower on the ploughed than on the grass site. After including estimates of photosynthesis in the analysis, ploughing led to significantly higher net CO2 emissions than from grassland. The main mechanism of C loss during ploughing was most likely due to a reduction in gross primary production rather than enhanced soil respiration.  相似文献   
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This study focuses on the empirical statistical analysis of the anomalies in daily precipitation extremes by applying the quantile perturbation method (QPM) to data from 31 Iranian weather stations during the period between 1961 and 2005. The possible causes behind the anomalies in precipitation extremes are identified by analyzing their relationship with the anomalies in eight atmospheric indices (i.e., NAO, SOI, PDO, AMO, NCP, DMI, WeMO, SSN). In terms of decadal oscillations, the country was generally wet in the 1960s and 1970s with most stations exhibiting periods of higher quantile perturbations, whereas lower quantile perturbations were dominant in the 1980s and 1990s. The highest perturbation in extreme precipitation quantiles prevails in Central Iran during the early 1980s, in which the quantiles are about 50% higher than the ones based on the full time series. The frequency of significant precipitation anomalies for winter season was greater than that for spring and autumn seasons. For the summer season, the humid region in North Iran demonstrates strong positive anomalies. The results highlight the noticeable role of large‐scale climatic factors in the anomalous behavior of precipitation extremes in Iran. The atmospheric drivers of the quantile anomalies in extreme precipitation were found to differ from one season to another.  相似文献   
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Primary ciliary dyskinesia (PCD), also referred to as immotile-cilia syndrome or Kartagener syndrome, is a group of genetic disorders caused by defective cilia leading to chronic sinupulmonary infection, situs inversus and reduced fertility. Some PCD patients also have cerebral ventriculomegaly or hydrocephalus. We report here two fetuses and one newborn with mild cerebral ventriculomegaly and a suspected and/or confirmed diagnosis of PCD. These cases demonstrate that mild fetal cerebral ventriculomegaly can be a prenatal sonographic marker of PCD, certainly in fetuses with situs inversus or a history of a previous sib with PCD. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
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Emerging evidence suggests that short episodes of high exposure to air pollution occur while commuting. These events can result in potentially adverse health effects. We present a quantification of the exposure of car passengers and cyclists to particulate matter (PM). We have simultaneously measured concentrations (PNC, PM2.5 and PM10) and ventilatory parameters (minute ventilation (VE), breathing frequency and tidal volume) in three Belgian locations (Brussels, Louvain-la-Neuve and Mol) for 55 persons (38 male and 17 female). Subjects were first driven by car and then cycled along identical routes in a pairwise design. Concentrations and lung deposition of PNC and PM mass were compared between biking trips and car trips.Mean bicycle/car ratios for PNC and PM are close to 1 and rarely significant. The size and magnitude of the differences in concentrations depend on the location which confirms similar inconsistencies reported in literature. On the other hand, the results from this study demonstrate that bicycle/car differences for inhaled quantities and lung deposited dose are large and consistent across locations. These differences are caused by increased VE in cyclists which significantly increases their exposure to traffic exhaust. The VE while riding a bicycle is 4.3 times higher compared to car passengers. This aspect has been ignored or severely underestimated in previous studies. Integrated health risk evaluations of transport modes or cycling policies should therefore use exposure estimates rather than concentrations.  相似文献   
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Evidence indicates that the concentration of stratospheric ozone has already decreased globally over the past several years and additional decreases are to be expected over the coming decades. A further depletion of the ozone layer would lead to an increase in the amount of ultraviolet (UV) radiation. One of the adverse effects of particularly UV-B radiation on human health would be an increase in the incidence of skin cancer. In this study an integrated model is presented to assist in assessing the changes in skin cancer incidences in relation to changes in the amount of stratospheric ozone, for the Netherlands and Australia. Although surrounded by large uncertainties, model results show that, in view of the several delay mechanisms and, additionally, the ageing of the population, future increases in skin cancer incidence cannot be reversed.  相似文献   
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Female philopatry in mammals is generally associated with ecological and sometimes social benefits, and often with dispersal by males. Previous studies on dispersal patterns of orangutans, largely non-gregarious Asian great apes, have yielded conflicting results. Based on 7?years of observational data and mitochondrial and nuclear DNA analyses on fecal samples of 41 adult Bornean orangutans (Pongo pygmaeus wurmbii) from the Tuanan population, we provide both genetic and behavioral evidence for male dispersal and female philopatry. Although maternally related adult female dyads showed similar home-range overlap as unrelated dyads, females spent much more time in association with known maternal relatives than with other females. While in association, offspring of maternally related females frequently engaged in social play, whereas mothers actively prevented this during encounters with unrelated mothers, suggesting that unrelated females may pose a threat to infants. Having trustworthy neighbors may therefore be a social benefit of philopatry that may be common among solitary mammals, thus reinforcing female philopatric tendencies in such species. The results also illustrate the diversity in dispersal patterns found within the great-ape lineage.  相似文献   
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The extent to which disarmament, demobilisation and reintegration (DDR) programmes initiated by state or multilateral agencies can realise the reintegration of ex‐combatants remains debated. While some consider that DDR should have the ambition to result in long‐term reintegration, others argue that DDR should focus on short‐term goals. This paper explores experiences with the reintegration of ex‐combatants in Burundi. It shows the interconnectedness of economic and social reintegration processes, and demonstrates that the reintegration of ex‐combatants cannot be seen in isolation from the wider recovery and development context in which DDR is taking place. Moreover, the case demonstrates that reconciliation and social reintegration are deeply interconnected, to the extent that social reintegration may fail if reconciliation is not taken into account. Rather than a debate between long‐ and short‐term goals, the focus should therefore be on increasing the understanding of reintegration processes and finding ways in which programmes can contribute to those.  相似文献   
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