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961.
Large, complex energy models present considerable challenges to develop and test. Uncertainty assessments of such models provide only partial guidance on the quality of the results. We have developed a model quality assistance checklist to aid in this purpose. The model checklist provides diagnostic output in the form of a set of pitfalls for the model application. The checklist is applied here to an energy model for the problem of assessing energy use and greenhouse gas emissions. Use of the checklist suggests that results on this issue are contingent on a number of assumptions that are highly value-laden. When these assumptions are held fixed, the model is deemed capable of producing moderately robust results of relevance to climate policy over the longer term. Checklist responses also indicate that a number of details critical to policy choices or outcomes on this issue are not captured in the model, and model results should therefore be supplemented with alternative analyses.  相似文献   
962.
The chemical characteristics of fine particulate matter (PM2.5) emitted from commercial cooking were explored in this study. Three typical commercial restaurants in Shanghai, i.e., a Shanghai-style one (SHS), a Sichuan-style one (SCS) and an Italian-style one (ITS), were selected to conduct PM2.5 sampling. Particulate organic matter (POM) was found to be the predominant contributor to cooking-related PM2.5 mass in all the tested restaurants, with a proportion of 69.1% to 77.1%. Specifically, 80 trace organic compounds were identified and quantified by gas chromatography/mass spectrometry (GC/MS), which accounted for 3.8%–6.5% of the total PM2.5 mass. Among the quantified organic compounds, unsaturated fatty acids had the highest concentration, followed by saturated fatty acids. Comparatively, the impacts of other kinds of organic compounds were much smaller. Oleic acid was the most abundant single species in both SCS and ITS. However, in the case of SHS, linoleic acid was the richest one. ITS produced a much larger mass fraction of most organic species in POM than the two Chinese cooking styles except for monosaccharide anhydrides and sterols. The results of this study could be utilized to explore the contribution of cooking emissions to PM2.5 pollution and to develop the emission inventory of PM2.5 from cooking, which could then help the policymakers design efficient treatment measures and control strategies on cooking emissions in the future.  相似文献   
963.
Almost two decades ago, Fleischmann and Pons reported excess enthalpy generation in the negatively polarized Pd/D-D2O system, which they attributed to nuclear reactions. In the months and years that followed, other manifestations of nuclear activities in this system were observed, viz. tritium and helium production and transmutation of elements. In this report, we present additional evidence, namely, the emission of highly energetic charged particles emitted from the Pd/D electrode when this system is placed in either an external electrostatic or magnetostatic field. The density of tracks registered by a CR-39 detector was found to be of a magnitude that provides undisputable evidence of their nuclear origin. The experiments were reproducible. A model based upon electron capture is proposed to explain the reaction products observed in the Pd/D-D2O system.
Pamela A. Mosier-BossEmail:
  相似文献   
964.
Reactive oxygen species (ROS)-induced DNA damage occurs in heavy metal exposure, but the simultaneous effect on DNA repair is unknown. We investigated the influence of co-exposure of lead (Pb), cadmium (Cd), and mercury (Hg) on 8-hydroxydeoxyguanosine (8-OHdG) and human repair enzyme 8-oxoguanine DNA glycosylase (hOGG1) mRNA levels in exposed children to evaluate the imbalance of DNA damage and repair. Children within the age range of 3–6 years from a primitive electronic waste (e-waste) recycling town were chosen as participants to represent a heavy metal-exposed population. 8-OHdG in the children’s urine was assessed for heavy metal-induced oxidative effects, and the hOGG1 mRNA level in their blood represented the DNA repair ability of the children. Among the children surveyed, 88.14% (104/118) had a blood Pb level >5 μg/dL, 22.03% (26/118) had a blood Cd level >1 μg/dL, and 62.11% (59/95) had a blood Hg level >10 μg/dL. Having an e-waste workshop near the house was a risk factor contributing to high blood Pb (r s  = 0.273, p < 0.01), while Cd and Hg exposure could have come from other contaminant sources. Preschool children of fathers who had a college or university education had significantly lower 8-OHdG levels (median 242.76 ng/g creatinine, range 154.62–407.79 ng/g creatinine) than did children of fathers who had less education (p = 0.035). However, we did not observe a significant difference in the mRNA expression levels of hOGG1 between the different variables. Compared with children having low lead exposure (quartile 1), the children with high Pb exposure (quartiles 2, 3, and 4) had significantly higher 8-OHdG levels (β Q2 = 0.362, 95% CI 0.111–0.542; β Q3 = 0.347, 95% CI 0.103–0.531; β Q4 = 0.314, 95% CI 0.087–0.557). Associations between blood Hg levels and 8-OHdG were less apparent. Compared with low levels of blood Hg (quartile 1), elevated blood Hg levels (quartile 2) were associated with higher 8-OHdG levels (β Q2 = 0.236, 95% CI 0.039–0.406). Compared with children having low lead exposure (quartile 1), the children with high Pb exposure (quartiles 2, 3, and 4) had significantly higher 8-OHdG levels.  相似文献   
965.
The sympatric neotropical termites Nasutitermes corniger and Nasutitermes ephratae are clearly distinguishable based on morphology, nest architecture, defensive secretion composition, and molecular markers. However, given the extensive ecological, geographical, and behavioral overlap of these closely related species, the potential for interbreeding may exist. To explore this possibility, heterospecific pairs were formed experimentally to examine courtship and colony-establishment behaviors, and reproductive potential. Courtship and nest construction behavior occurred in heterospecific pairs in a similar manner to that of conspecific pairs. Survival of pairs depended upon the species of the female partner. N. ephratae females paired with N. corniger males produced as many offspring as conspecific pairs. N. corniger females mated to N. ephratae males, however, produced significantly fewer offspring at 60 days post-establishment than the reciprocal cross or conspecific N. ephratae or N. corniger pairs. This was also the only pairing in which any aggression was observed. Heterospecific pairs and groups formed in mate choice mesocosms, suggesting that species recognition between these two termites is not an important aspect of mate choice. Overall, species mismatch tolerance and hybrid offspring viability are high. The present data, together with previous evidence from defensive secretions and isozyme analysis, suggest that hybridization may periodically occur in nature, and that reproductive barriers between these two species may be incomplete. Hybridization could provide a rare but important source of genetic diversity and may ensure mating opportunities for the more abundant sex of alates in each species.  相似文献   
966.
The widespread contamination of surface and ground water quality from the heavy use of fertilizer in modern agriculture is the current concern. Therefore, this study was carried out to develop a slow-release fertilizer using charcoal. The morphology of the charcoal impregnated fertilizer was investigated by scanning electron microscopy (SEM). This study also evaluated the release patterns of N, P, and K from impregnated charcoal using a simulated soil solution and distilled water as leaching solutions. The patterns of N, P, and K releases were examined in both static and continuous-flow conditions for 360 h. Releases of N, P, and K from impregnated charcoal were found to be slow and steady. However, the release trends of N, P, and K were higher in soil solution than distilled water under both the above conditions. Dissolution occurred when N, P, and K were released in the above leached solutions. As a result, the fertilizer impregnated charcoal could be developed as slow-release type fertilizer to minimize the contamination.  相似文献   
967.
We used microsatellite genetic markers to investigate adult population structure and the formation of a new year-class in Sebastes mystinus (blue rockfish). Since S. mystinus may live as long as 45 years and reach reproductive age at approximately 5 years, the adult population may contain as many as eight generations of reproductive adults. We investigated whether the juveniles of the 2000 year-class and the adult population were genetically homogeneous along the California coast. We sampled approximately 100 juveniles from three sites, two sites along the Monterey Peninsula (Carmel and Monterey) in central California and one at Fort Ross in northern California, and approximately 50 adult S. mystinus from five sites throughout the population center. The adult sampling spanned approximately 700 km from the northern Channel Islands to Fort Bragg. The juveniles showed significant heterogeneity in allele frequencies among distant locations and genetic homogeneity among adjacent locations. In contrast, the adults showed genetic homogeneity over large distances (San Miguel Island to Fort Bragg), indicating little limitation of gene flow in this region. Allele frequencies of juveniles differed from adult samples and in some cases reduced genetic diversity indicative of sweepstakes recruitment (small sample of the adult reproductive potential). The genetic structure of the 2000 year-class suggests that despite a genetically homogenous adult population, settled juveniles can be genetically heterogeneous along the California coast. The results also suggest that the adults, with several year-classes, are capable of maintaining a panmictic population despite the genetic distinctiveness of individual year-classes.  相似文献   
968.
The reestablisment of autochthonous plant species is an essential strategy for recovering degraded areas under semiarid conditions. A field experiment was carried out to assess the short-term effect of two reafforestation methods involving mycorrhizal inoculation and compost addition on soil quality parameters and Rhamnus lycioides seedling growth. The nutrient content (NPK) and enzymatic activities (dehydrogenase, urease, protease-BAA, acid phosphatase and β-glucosidase) increased and bulk density decreased in the rhizosphere soil with the organic amendment. Biomass C of rhizosphere soil increased by at least 240% with respect to the control soil after mycorrhizal inoculation and the combination of compost addition + mycorrhizal inoculation. Both mycorrhizal inoculation and composted organic residue addition increased R. lycioides seedling growth in the same proportion. In the short term, we conclude that the application of both reafforestation methods not only enhances the establishment of R. lycioides seedlings, but also improves soil quality.  相似文献   
969.
Sexual ornaments might reliably indicate the ability to cope with parasites and diseases, and a better ability to mount a primary inflammatory response to a novel challenge. Carotenoid-based ornaments are amongst the commonest sexual signals of birds and often influence mate choice. Because carotenoids are immuno-stimulants, signallers may trade-off allocating these to ornamental colouration or using them for immune responses, so carotenoid-based ornaments might be particularly useful as honest indicators of immuno-compentence. Tetraonid birds, such as the red grouse Lagopus lagopus scoticus, exhibit supra-orbital yellow-red combs, a conspicuous ornament which functions in intra- and inter-sexual selection. The colour of combs is due to epidermal pigmentation by carotenoids, while their size is testosterone-dependent. In this study, I investigated whether comb characteristics, and in particular, comb colour, indicated immuno-competence in free-living male red grouse. I assessed T-cell-mediated immunity using a standardised challenge with phytohaemagglutinin. Red grouse combs reflect in the red and in the ultraviolet spectrum of light, which is not visible to humans but that grouse most likely see, so I measured comb colour across the whole bird visible spectrum (300-700 nm) using a reflectance spectrometer. I found that males with bigger and redder combs, but with less ultraviolet reflectance, had greater T-cell-mediated immune response. Comb colour predicted T-cell-mediated immune response better than comb size, indicating that the carotenoid-based colouration of this ornament might reliably signal this aspect of male quality.  相似文献   
970.
Lu J  Wu J  Fu Z  Zhu L 《Environmental management》2007,40(6):823-830
The invasion of water hyacinth (Eichhornia crassipes) has resulted in enormous ecological and economic consequences worldwide. Although the spread of this weed in Africa, Australia, and North America has been well documented, its invasion in China is yet to be fully documented. Here we report that since its introduction about seven decades ago, water hyacinth has infested many water bodies across almost half of China’s territory, causing a decline of native biodiversity, alteration of ecosystem services, deterioration of aquatic environments, and spread of diseases affecting human health. Water hyacinth infestations have also led to enormous economic losses in China by impeding water flows, paralyzing navigation, and damaging irrigation and hydroelectricity facilities. To effectively control the rampage of water hyacinth in China, we propose a sustainability science-based management framework that explicitly incorporates principles from landscape ecology and Integrated Pest Management. This framework emphasizes multiple-scale long-term monitoring and research, integration among different control techniques, combination of control with utilization, and landscape-level adaptive management. Sustainability science represents a new, transdisciplinary paradigm that integrates scientific research, technological innovation, and socioeconomic development of particular regions. Our proposed management framework is aimed to broaden the currently dominant biological control-centered view in China and to illustrate how sustainability science can be used to guide the research and management of water hyacinth.  相似文献   
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