Development of a livestock odor dispersion model: part I. Model theory and development

A livestock odor dispersion model (LODM) was developed to predict mean odor concentration, odor frequency, instantaneous odor concentration, and peak odor concentration from livestock operations. This model is based on the Gaussian fluctuating plume model and has the ability to consider the instantaneous concentration fluctuations and the differences between odor and traditional air pollutants. It can predict odor frequency from the routine hourly meteorological data input and deal with different types of sources and multiple sources. Also, the relationship between odor intensity and odor concentration was incorporated into the model.     

环境基质中药物残留的固相提取与分析

废水流出物常常不可避免地进入地表水和用于饮用水资源的含水层．因废水再循环常常进入饮用水层,各种废水中的污染物最终会污染饮用水．以往环保部门一直比较注重农药和工业污染物,但最近的研究发现:废水流出物中的某些药物残留已达到了相当令人关注(１μｇ·１－１即ｐｐｂ)的程度．传统的分析技术(如液液萃取和ＧＣ/ＭＳ) 对极性较弱的化合物(ＰＣＢｓ和许多农药)比较有效,但对于极性相对较强的药物污染物而言,固相提取(ＳＰＥ)与ＬＣ/ＭＳ技术更适合于样品提取分析。     

Conservation resource allocation,small population resiliency,and the fallacy of conservation triage

Some conservation prioritization methods are based on the assumption that conservation needs overwhelm current resources and not all species can be conserved; therefore, a conservation triage scheme (i.e., when the system is overwhelmed, species should be divided into three groups based on likelihood of survival, and efforts should be focused on those species in the group with the best survival prospects and reduced or denied to those in the group with no survival prospects and to those in the group not needing special efforts for their conservation) is necessary to guide resource allocation. We argue that this decision-making strategy is not appropriate because resources are not as limited as often assumed, and it is not evident that there are species that cannot be conserved. Small population size alone, for example, does not doom a species to extinction; plants, reptiles, birds, and mammals offer examples. Although resources dedicated to conserving all threatened species are insufficient at present, the world's economic resources are vast, and greater resources could be dedicated toward species conservation. The political framework for species conservation has improved, with initiatives such as the UN Sustainable Development Goals and other international agreements, funding mechanisms such as The Global Environment Facility, and the rise of many nongovernmental organizations with nimble, rapid-response small grants programs. For a prioritization system to allow no extinctions, zero extinctions must be an explicit goal of the system. Extinction is not inevitable, and should not be acceptable. A goal of no human-induced extinctions is imperative given the irreversibility of species loss.     

Discharge of oilfield-produced water in nueces bay,texas: A case study

During oil and gas production, water is often extracted from geological formations along with the hydrocarbons. These "produced waters" have been discharged to Nueces Bay since the turn of the century. These effluents were found to be highly toxic, and sediments in the vicinity of the discharges were also toxic. We developed a map of wells and produced-water discharge sites in the vicinity of Nueces Bay and identified numerous unplugged wells suitable for conversion to produced water disposal wells. An economic analysis of conversion to subterranean injection of produced water indicates that most of the wells currently in production could pay out the cost of conversion to injection in one to three years. The use of one injection well for two or more water-producing wells could yield greater savings. Wells that could not support the cost of injection are small producers, and their loss would not constitute a major loss of jobs or dollars to the area. This study could serve as a useful model for evaluating the economic feasibility of conversion to injection in other areas of Texas and Louisiana.     

Evaluation of prenatal diagnosis by a registry of congenital anomalies

Prenatal diagnosis performed by fetal karyotype and ultrasound scan is now a routine part of antenatal care in many countries. How many fetal anomalies are actually detected by these procedures? We have used our registry of congenital malformations to answer this question. In our region, prenatal diagnosis was performed in 23.1 per cent of fetuses with a chromosomal aberration and in 20.1 per cent of fetuses with non-chromosomal anomalies. Only 6.9 per cent of the pregnancies with fetuses with non-chromosomal anomalies were terminated. The sensitivity of prenatal diagnosis by ultrasonographic examination was much lower for isolated malformations (fetuses with only one anomaly) than for multiple malformed children, 15.3 and 48.3 per cent respectively, chromosomal anomalies excluded.     

Increasing UV-B radiation at the earth's surface and potential effects on aqueous mercury cycling and toxicity

In the past two decades, a great deal of attention has been paid to the environmental fate of mercury (Hg), and this is exemplified by the growing number of international conferences devoted uniquely to Hg cycling and its impacts on ecosystem functions and life. This interest in the biogeochemistry of Hg has resulted in a significant improvement of our understanding of its impact on the environment and human health. However, both past and current research, have been primarily oriented toward the study of direct impact of anthropogenic activities on Hg cycling. Besides a few indirect effects such as the increase in Hg methylation observed in acid-rain impacted aquatic systems or the reported enhanced Hg bioaccumulation in newly flooded water reservoirs; changes in Hg transformations/fluxes that may be related to global change have received little attention. A case in point is the depletion of stratospheric ozone and the resulting increase in solar UV-radiation reaching the Earth. This review and critical discussion suggest that increasing UV-B radiation at earth's surface could have a significant and complex impact on Hg cycling including effects on Hg volatilization (photo-reduction), solubilization (photo-oxidation), methyl-Hg demethylation, and Hg methylation. Therefore, this paper is written to provoke discussions, and more importantly, to stimulate research on potential impacts of incoming solar UV-radiation on global Hg fluxes and any toxicity aspects of Hg that may become exacerbated by UV-radiation.     

Diversity pattern and spatial scale: a study of a tropical rain forest of Malaysia

Scale is emerging as one of the critical problems in ecology because our perception of most ecological variables and processes depends upon the scale at which the variables are measured. A conclusion obtained at one scale may not be valid at another scale without sufficient knowledge of the scaling effect, which is also a source of misinterpretation for many ecological problems, such as the design of reserves in conservation biology.This paper attempts to study empirically how scaling may affect the spatial patterns of diversity (tree density, richness and Shannon diversity) that we may perceive in tropical forests, using as a test-case a 50 ha forest plot in Malaysia. The effect of scale on measurements of diversity patterns, the occurrence of rare species, the fractal dimension of diversity patterns, the spatial structure and the nearest-neighbour autocorrelation of diversity are addressed. The response of a variable to scale depends on the way it is measured and the way it is distributed in space.We conclude that, in general, the effect of scaling on measures of biological diversity is non-linear; heterogeneity increases with the size of the sampling units, and fine-scale information is lost at a broad scale. Our results should lead to a better understanding of how ecological variables and processes change over scale.     

未来决策的工具:货币与生物物理学指标相结合

考虑货币指标信息的利害,关系到一个国家的财富,它对于保护国家财富、维护国家经济命脉是不可或缺的 .生物物理学指标的考虑,则关系到国内和全球天然资产的使用 .经济命脉的维护有赖于基本的生态贡献,诸如可更新和不可更新资源、废物的消纳与稳定的气候条件等 .这两项计量指标共同为决策者们提供了经济与生态生存能力的详尽资料 .这样一种方法也可以用来解释国家与全球之间的可持续性关系,以及参与政策的制定 .