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1.
The US and Canadian weather service heat indices were evaluated to determine if one is a better predictor of the risk of heat injury. Heat index values were compared to the rectal temperature predicted by a heat-balanced-based thermal model to determine if there was a statistically significant relation between the heat index values and predicted rectal temperature. R2 values ranged between 0.96 and 0.99 for the conditions investigated. Equations that predicted rectal temperature from the heat indices are presented. Both indices are highly correlated with predicted rectal temperatures.  相似文献   

2.
Anker's medium with glucose and Thornton's medium were most suitable for growing Enterobacter aerogenes and Bacillus subtilis respectively, antagonists of P. cactorum, the causal agent of apple crown rot. Calcium nitrate was thebest source of nitrogen for growing cultures of E. aerogenes and B. subtilis. E. aerogenes produced the maximum amount of antifungal substance at 200 and 400 mg/l of nitrogen in the medium. Phosphate supplied either in the potassium or calcium form did not change the growth of either antagonist. An addition of 200 mg/l of N and 400 mg/l of P significantly enhanced the production of antifungal substance by E. aerogenes on Anker's medium with glucose. Thornton's medium supplemented with 200 mg/l of N and 100 mg/l of P produced the maximum amount of antifungal substance from B. subtilis. Generally, soil extracts without enrichment did not support the growth of either antagonist; E. aerogenes required at least 400 mg/lof, both N and P while B. subtilis required 200 mg/l of N and 800 mg/l of P for the maximum production of antifungal substance. When ammonium phosphate was added to soil extracts, only a small amount of antifungal substance was produced by E. aerogenes and none by B. subtilis. These results indicate that E. aerogenes and B. subtilis need N and P fertilization of the sterilized soil for the maximum production of the antifungal substance that inhibits the growth of P. cactorum.  相似文献   

3.
Our personal values are subject to forces of social influence. Deontological resolve captures how strongly one relies on absolute rules of right and wrong in the representation of one''s personal values and may predict willingness to modify one''s values in the presence of social influence. Using fMRI, we found that a neurobiological metric for deontological resolve based on relative activity in the ventrolateral prefrontal cortex (VLPFC) during the passive processing of sacred values predicted individual differences in conformity. Individuals with stronger deontological resolve, as measured by greater VLPFC activity, displayed lower levels of conformity. We also tested whether responsiveness to social reward, as measured by ventral striatal activity during social feedback, predicted variability in conformist behavior across individuals but found no significant relationship. From these results we conclude that unwillingness to conform to others'' values is associated with a strong neurobiological representation of social rules.  相似文献   

4.
This study evaluates how equilibrium vapor concentrations above petroleum solvent mixtures are affected by total aromatic content and the implications for estimating benzene vapor exposures. Headspace vapor concentrations over mixtures with liquid benzene content ranging from 0.001 to 1.0% and varying percentages of 1,2,4-trimethylbenzene and n-nonane were studied using a direct-injection gas chromatography/flame ionization detection method that showed good precision. The measured values were compared to predictions based on Raoult's Law, with and without non-ideality corrections using activity coefficients. Ratios of vapor to liquid benzene concentrations decreased with increasing total aromatic content; that is, mixtures with 10% to 20% trimethylbenzene simulating non-hydrotreated mineral spirits had much lower ratios compared to the ≥99% aliphatic mixtures that simulate hydrotreated mineral spirits. Positive deviations from Raoult's Law were greatest at liquid benzene concentrations less than 0.1%, particularly in the predominantly aliphatic mixtures. Correcting for non-ideality using activity coefficients resulted in predicted vapor concentrations that were closer to measured values. The data indicate that higher aromatic content and higher liquid benzene content suppress benzene vapor concentrations due to benzene's greater affinity for similar aromatic molecules in solution. Benzene exposure reconstructions should consider actual composition of the historic material with respect to aromatic content.  相似文献   

5.
Abstract We consider a mathematical model for the coevolution of a plant's defense against herbivores and the herbivore's ability to exploit the plant. The result of coevolution is predicted using the phase portrait of trait value dynamics and contour plots of fitnesses. The following results are derived: (1) The fitnesses of both plant and herbivore are higher at an “armless” state in which both plant and herbivore invest a minimum amount of energy and/or resources in defense and feeding respectively, than at the coevolutionarily stable state (CSS); (2) Perpetual increase in the trait values of both species may occur when the marginal costs of defense and feeding abilities decrease as these abilities increase; (3) If the marginal costs of defense and feeding abilities increase as the abilities increase, there is a coevolutionary equilibrium with finite trait values; (4) There may be more than one coevolutionarily stable state (CSS).  相似文献   

6.
China's bioenergy potential   总被引:2,自引:0,他引:2  
Despite great enthusiasm about developing renewable energy in China, the country's bioenergy potential remains unclear. Traditional utilization of bioenergy through primarily household combustion of crop residue and fuelwood is still a predominant energy source for rural China. More efficient utilization of ~300 million tons of crop residues for bioelectricity generation could add a couple of percent of renewable energy to China's total energy production. With <9% of the world's arable land supporting ~20% of the world's population, China is already a net grain importer and has little extra farmland for producing a significantly additional amount of biofuels from first‐generation energy crops, such as maize, sugarcane, and soybean. Second‐generation energy crops hold the greatest potential for bioenergy development worldwide. Miscanthus, a native perennial C4 grass that produces high biomass across almost the entire climatic zone of China, is the most promising second‐generation energy crop to domesticate and cultivate. A reasonable near‐term goal is to produce 1 billion tons of Miscanthus biomass annually from ~100 million hectares of marginal and degraded land concentrated in northern and northwestern China. This can generate ~1458 TW h electricity and mitigate ~1.7 billion tons of CO2 emission from power coal, which account for ~45% of China's electricity output and ~28% of CO2 emission in 2007. Furthermore, growing perennial grasses on marginal and degraded land will contribute to the ongoing efforts in China to restore vast areas of land under serious threat of desertification. With this potential taken into account, bioenergy can play a major role in meeting China's rapidly growing energy demand while substantially reducing greenhouse gas emission.  相似文献   

7.
Abstract

The values of the different terms contributing to the free energy of a polyelectrolyte in ionic solution, calculated according to Manning's model are compared with those predicted by the Poisson—Boltzmann (P—B) equation solved for the cell model. On this ground, the limits of applicability of Manning's model and some of its features are discussed. The comparison confirms the usefulness of Manning's model for low charge density polyelectrolytes, while for higher charge densities some care should be used due to the breakdown of the approximations underlying the model.  相似文献   

8.
基于生态系统服务理论的中国绿色经济转型预测分析   总被引:2,自引:0,他引:2  
郑德凤  臧正  孙才志  李红英 《生态学报》2014,34(23):7137-7147
着眼于中国绿色经济转型之路的科学预测与分析,借鉴传统环境负荷模型以及资源与经济脱钩理论、区位熵理论等,提出基于生态系统服务理论的有关绿色经济指标评价模型。应用该模型计算出2001—2010年全球及中国有关绿色经济指标,依照未来中国经济与社会发展规划目标,预计"十二五"末期中国经济发展中的资源消耗及环境损失成本、人均绿色GDP将分别达到3.11×1012美元、0.37×104美元,生态负荷强度、资源脱钩指数及绿色GDP的区位熵指数分别为0.38、0.66、75;2020年中国绿色GDP的区位熵指数将超越全球平均水平、2024年人均GDP将突破1万美元关口步入中等发达国家行列。计算结果表明中国生态系统压力逐年降低、资源利用效率、环境绩效与经济效益同步提高,逐渐在全球经济绿色转型过程中发挥重要作用;未来,中国仍需秉承"共同但有区别的责任"原则,处理好与其他国家的权责纷争;同时积极推进节能减排、经济结构调整工作,进一步协调好城乡之间、区域之间经济社会发展与自然资源及生态环境的关系。  相似文献   

9.
贾小乐  周源  延建林  魏亿钢 《生态学报》2019,39(17):6487-6499
采用能值理论与分析方法,研究2015年环太湖城市群生态经济系统的能值流量,并构建多维度的生态经济系统指标体系,综合评价环太湖城市群可持续发展程度和健康水平。研究结果表明:(1)可更新资源利用不足,在能值利用总量中占比最大值仅为7.95%;(2)不可更新资源消耗过度,在能值利用总量中占比最小值达到56.95%;(3)(除苏州市外)可更新资源产品中肉类与水产品占比最小值已达63.08%,急需对传统的农业结构进行调整;(4)不可更新资源产品均以水泥和钢铁为主,占比最小值已达88.02%,应该加快传统的工业转型升级;(5)输入能值占比最大值仅为36.27%,商品进出口呈现贸易顺差,对外经济开放仍有发展空间;(6)废弃物与可更新能值比率最大值仅为12.8%,废弃物能值比最小值仅为0.19%,废弃物排放和利用水平有待提高;(7)湖州市可持续指标ESI和能值可持续发展指标EISD为1.59和2.99,在环太湖城市群中更具可持续发展潜力;(8)苏州市健康能值指数EUEHI和改进的健康能值指数EUEHI''为8.22和1.65,在环太湖城市群中健康水平较低。据此结果提出了有助于环太湖城市群经济社会发展与自然生态环境和谐共赢的可持续发展对策。  相似文献   

10.
In the midst of economic crisis, the Greek state has taken the unprecedented step of opening many of the nation's closed business sectors to international investors. Opportunities for multinational investment have been most prolific in the arena of renewable energy, where foreign prospecting in solar and wind energy is soaring. This article discusses two renewable energy initiatives: photovoltaic parks on agricultural land in Thessaly, central mainland Greece, and a planned wind farm development on the Aegean island of Chios. Among the people of Thessaly and Chios, the renewable energy initiatives are widely seen in terms of conquest and occupation akin to the Ottoman era and the Second World War. Harnessing natural resources is perceived to be a colonial programme of economic extraction associated with the global South as much as a sustainable energy initiative, heralding a return to a time of foreign occupation. This article examines the dialectical relationship emerging between narratives of renewable energy extraction and broader, long‐standing conceptions of Greek identity.  相似文献   

11.
《Ecological Indicators》2008,8(5):647-656
Use and production of building materials, such as cement and concrete, is a major cause of global ecological problems with special reference to the overexploitation of non-renewable natural resources due to high temperature production processes, fossil fuels combustion, extraction of raw materials and non-recycling. In this paper, an environmental accounting method was applied to the production of cement and concrete in order to evaluate its dependence on natural resources even non-renewable and heavily relied on external inflows. The main steps of the production process (1) cement production, (2) transport of materials and (3) concrete mixing, were assessed by the emergy analysis (spelled with an “m”). This was performed to measure the amount of environmental resource use in terms of equivalent solar energy, extending the energy hierarchy principle to building materials. The resulting unit emergy values of cement and concrete were compared with previous emergy assessments in order to highlight how emergy analysis is sensitive to local context and reference system's boundaries. An Emergy Investment Ratio (EIR) was assessed and presented as a synthetic indicator of sustainability. Results showed a high dependence of cement and concrete production on external resource flows. Furthermore, the high value of EIR suggested a weak competitive capacity due to a high sensitivity to external instabilities.  相似文献   

12.
We consider sample size determination for ordered categorical data when the alternative assumption is the proportional odds model. In this paper the sample size formula proposed by Whitehead (Statistics in Medicine, 12 , 2257–2271, 1993) is compared with the methods based on exact and asymptotic linear rank tests with Wilcoxon and trend scores. We show that Whitehead's formula, which is based on a normal approximation, works well when the sample size is moderate to large but recommend the exact method with Wilcoxon scores for small sample sizes. The consequences of misspecification in models are also investigated.  相似文献   

13.
陈伟  耿涌  黄斌斌  钟绍卓  高子彦  吴非  尤炜  宋晓倩 《生态学报》2019,39(21):7904-7913
青海省海西蒙古族藏族自治州(简称海西州)生态环境脆弱,快速发展的工业活动对当地生态环境造成严重破坏。海西州地处青藏高原东北部,是我国重要的生态安全屏障之一,在全国生态建设中处于特殊地位。能值分析法是一种基于热力学理论的环境核算方法。利用能值分析法对海西州生态经济系统运行现状进行评估;并应用能值指标评价海西州生态经济系统的可持续发展水平;通过对能值指标的时间序列分析揭示海西州生态经济系统的发展趋势,以期为海西州生态经济系统的可持续发展提供参考依据。研究结果表明,2016年支撑海西州生态经济系统运行的总能值投入量为6.69×1024 sej,是2010年总能值投入量的1.94倍。在2010-2016年的7年内,不可更新资源的能值投入占当年总能值投入量的比例均超过90%,而可更新资源能值投入量与从系统外输入到海西州的能值量占比均较低。基于能值的指标分析显示:海西州的人均能值使用量、能值密度、能值货币比率、环境负载率分别从2010年的8.84×1018 sej/人、1.15×1013 sej/m2、3.05×1014 sej/US$、103.02增加到2016年的1.65×1019 sej/人、2.22×1013 sej/m2、9.12×1014 sej/US$、213.47;而相应的能值产出率、能值可持续发展指数则分别从2010年的2.66×103和25.84降低到2016年的1.23×103和5.74。研究结果表明虽然海西州经济得到发展、人民生活质量得到提高,而经济发展对当地不可再生资源依赖较大,给环境造成的压力不断增加。为从长远角度实现海西州的可持续发展,亟需转变经济发展方式,降低对不可更新能源的过度开发。此外,研究结果显示,海西州的能值交换率小于1,这说明研究时间范围内,海西州在对外贸易过程中处于不利地位,因此需增加单位产品的附加值以促进能值流的合理流动。  相似文献   

14.
《Genomics》2020,112(6):4777-4787
An increasing number of research shows that long non-coding RNA plays a key role in many important biological processes. However, the number of disease-related lncRNAs found by researchers remains relatively small, and experimental identification is time consuming and labor intensive. In this study, we propose a novel method, namely HAUBRW, to predict undiscovered lncRNA-disease associations. First, the hybrid algorithm, which combines the heat spread algorithm and the probability diffusion algorithm, redistributes the resources. Second, unbalanced bi-random walk, is used to infer undiscovered lncRNA disease associations. Seven advanced models, i.e. BRWLDA, DSCMF, RWRlncD, IDLDA, KATZ, Ping's, and Yang's were compared with our method, and simulation results show that the AUC of our method is more perfect than the other models. In addition, case studies have shown that HAUBRW can effectively predict candidate lncRNAs for breast, osteosarcoma and cervical cancer. Therefore, our approach may be a good choice in future biomedical research.  相似文献   

15.
Complexity of scaffold geometries and biological mechanisms involved in the bone generation process make the design of scaffolds a quite challenging task. The most common approaches utilized in bone tissue engineering require costly protocols and time-consuming experiments. In this study we present an algorithm that, combining parametric finite element models of scaffolds with numerical optimization methods and a computational mechano-regulation model, is able to predict the optimal scaffold microstructure. The scaffold geometrical parameters are perturbed until the best geometry that allows the largest amounts of bone to be generated, is reached. We study the effects of the following factors: (1) the shape of the pores; (2) their spatial distribution; (3) the number of pores per unit area. The optimal dimensions of the pores have been determined for different values of scaffold Young''s modulus and compression loading acting on the scaffold upper surface.Pores with rectangular section were predicted to lead to the formation of larger amounts of bone compared to square section pores; similarly, elliptic pores were predicted to allow the generation of greater amounts of bone compared to circular pores. The number of pores per unit area appears to have rather negligible effects on the bone regeneration process. Finally, the algorithm predicts that for increasing loads, increasing values of the scaffold Young''s modulus are preferable.The results shown in the article represent a proof-of-principle demonstration of the possibility to optimize the scaffold microstructure geometry based on mechanobiological criteria.  相似文献   

16.
With its high energy content and clean combustion, hydrogen is recognized as a renewable clean energy source with enormous potential. Biological hydrogen production is a promising alternative with significant advantages over conventional petroleum‐derived chemical processes. Sustainable hydrogen production from renewable resources such as cassava, wastewater, and other agricultural waste is economically feasible for industrial applications. So far, the major bottlenecks in large‐scale biological hydrogen production are the low production rate and yield. This review discusses the various factors that affect the metabolic pathways of dark hydrogen production, and highlights the state‐of‐the‐art development of mixed culture technology. The aim of this review is to provide suggestions for the future directions of mixed culture technology, as well as by‐product valorization in dark fermentation.  相似文献   

17.
Different methods have been compared for the estimation of solar heat load on man. The comparison comprised several methods based on the calculation of absorbed solar radiation and one method for calculation of mean radiant temperature (Mrt). Regression analysis was carried out for predicted values and values calculated for a vertical cylinder, assumed as an analog model of a standing man. Regression of mean skin temperature, measured in 10 subjects exposed to solar radiation under a variety of climatic conditions, on predicted radiant heat load was also analysed. Mean skin temperature correlated best withMrt, accounting for more than 50% of the variance. The results indicated that three methods provide a realistic estimation of the radiation heat load, whereas some methods show deviations of several hundred per cent.  相似文献   

18.
The present investigation focuses the flow and heat transfer characteristics of the steady three-dimensional Sisko fluid driven by a bidirectional stretching sheet. The modeled partial differential equations are reduced to coupled ordinary differential equations by a suitable transformation. The resulting equations are solved numerically by the shooting method using adaptive Runge Kutta algorithm in combination with Newton''s method in the domain [0,∞). The numerical results for the velocity and temperature fields are graphically presented and effects of the relevant parameters are discussed in detail. Moreover, the skin-friction coefficient and local Nusselt number for different values of the power-law index and stretching ratio parameter are presented through tabulated data. The numerical results are also verified with the results obtained analytically by the homotopy analysis method (HAM). Additionally, the results are validated with previously published pertinent literature as a limiting case of the problem.  相似文献   

19.
Sustainable urban resource management depends essentially on a sound understanding of a city's resource flows. One established method for analyzing the urban metabolism (UM) is the Eurostat material flow analysis (MFA). However, for a comprehensive assessment of the UM, this method has its limitations. It does not account for all relevant resource flows, such as locally sourced resources, and it does not differentiate between flows that are associated with the city's resource consumption and resources that only pass through the city. This research sought to gain insights into the UM of Amsterdam by performing an MFA employing the Eurostat method. Modifications to that method were made to enhance its performance for comprehensive UM analyses. A case study of Amsterdam for the year 2012 was conducted and the results of the Eurostat and the modified Eurostat method were compared. The results show that Amsterdam's metabolism is dominated by water flows and by port‐related throughput of fossil fuels. The modified Eurostat method provides a deeper understanding of the UM than the urban Eurostat MFA attributed to three major benefits of the proposed modifications. First, the MFA presents a more complete image of the flows in the UM. Second, the modified resource classification presents findings in more detail. Third, explicating throughput flows yields a much‐improved insight into the nature of a city's imports, exports, and stock. Overall, these advancements provide a deeper understanding of the UM and make the MFA method more useful for sustainable urban resource management.  相似文献   

20.
A method for predicting RNA structure from amino-acid sequence data   总被引:1,自引:0,他引:1  
A method is presented that enables computation of the stability of hairpin loops in an RNA chain, knowing only the amino-acid sequence translated from that chain. The method is based on a statistical decoding procedure and a thenno-dynamic evaluation of bonding in terms of free energy. The decoding takes into account all triplets of bases for each amino acid. Every possible hairpin loop formed by bonding between base pairs is examined by a computer program. Using thermodynamic criteria, it is decided which loops have a high probability of being bound. For these, a free energy of loop formation is evaluated in order to predict stability. The method is tested on 54 amino-acid sequences obtained by translating 18 different tRNA's. The loops predicted from the amino-acid sequence are compared with their actual counterparts in the original nucleotide sequence. A strong positive correlation is observed between the predicted and actual stabilities. A hairpin loop predicted to be stable from the amino-acid sequence has, on average, a probability of 0.5 of being stable, 0.3 of being metastable and 0.2 of being unstable, in the actual nucleotide sequence. Various applications of this method to obtain information about sequence and structure in messenger RNA's are discussed.  相似文献   

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