The marine toxin, okadaic acid (OA) is produced by dinoflagellates of the genera Prorocentrum and Dinophysis and is the causative agent of the syndrome known as diarrheic shellfish poisoning. In addition, OA acts as both a tumor promoter, attributed to OA-induced inhibition of protein phosphatases as well as an inducer of apoptosis. To better understand the potentially divergent toxicological profile of OA, the concentration-dependent cytotoxicity and alterations in gene expression on the human liver tumor cell line HepG2 upon OA exposure were determined using RNA microarrays, DNA fragmentation, and cell proliferation assays as well as determinations of cell detachment and cell death in different concentrations of OA. mRNA expression was quantified for approximately 15,000 genes. Cell attachment and proliferation were both negatively correlated with OA concentration. Detached cells displayed necrotic DNA signatures but apoptosis also was broadly observed. Data suggest that OA has a concentration dependent effect on cell cycle, which might explain the divergent effects that at low concentration OA stimulates genes involved in the cell cycle and at high concentrations it stimulates apoptosis. 相似文献
Aerosol backscatter measurements from a Vaisala CL31 ceilometer are compared directly with a co-located 532/1064 nm lidar in order to validate the CL31 for remote sensing of vertical aerosol structure. The cases examined include a significant aerosol event (biomass burning), which by virtue of its vertical extent, provides a robust measure of the vertical range of the ceilometer for aerosol applications. A second case is presented when the instruments were separated in order to illustrate the utility of a network of such instruments for elucidating spatial patterns in aerosol distribution and the advection of elevated pollutant layers. When co-located, the instruments show remarkable agreement and indicate that the CL31 can detect aerosol layers up to 3000 m AGL in ideal conditions (at night and with high aerosol concentrations as found in biomass burning or dust plumes). When separated, multiple instruments provide an opportunity to examine advection of pollutant layers as well as their evolution. This suggests that installation of a ceilometer network would provide a cost-effective means of examining three-dimensional aspects of regional air quality as well as distinguishing between regional and local sources of pollution 相似文献
Criteria used to identify crypto-explosive structures as of impact origin imply only shock. Geographical distribution of many localities is non-random and relates to distribution of carbonatites and other igneous rocks. The implications are important and numerous. One is that some “meteorites” are almost certainly Earth material, another that tektites are entirely terrestrial. 相似文献
The large-scale industrial production and processing of munitions such as 2,4,6-trinitrotoluene (TNT) over the past 100 years led to the disposal of wastes containing explosives and nitrated organic by-products into the environment. In the US, the Army alone has estimated that over 1.2 million tons of soil have been contaminated with explosives, and the impact of explosives contamination in other countries is of similar magnitude. In recent years, growing concern about the health and ecological threats posed by man-made chemicals have led to studies of the toxicology of explosives, which have identified toxic and mutagenic effects of the common military explosives and their transformation products (Bruns-Nagel et al., 1999a; Fuchs et al., 2001; Homma-Takeda et al., 2002; Honeycutt et al., 1996; Rosenblatt et al., 1991; Spanggord et al., 1982; Tan et al., 1992 and Won et al., 1976). Because the cleanup of areas contaminated by explosives is now mandated because of public health concerns, considerable effort has been invested in finding economical remediation technologies. Biological treatment processes are often considered, since these are usually the least expensive means of destroying organic pollution. This review examines the most important groups of chemicals that must be treated at sites contaminated by explosives processing, the chemical and biological transformations they undergo, and commercial processes developed to exploit these transformations for treatment of contaminated soil. We critically examine about 150 papers on the topic, including approximately 60 published within the past 5 years. 相似文献
The diversity of shelters used in transitional settlements for internally displaced persons (IDPs) in Herat, Afghanistan is described. The information is based on a field survey undertaken in March 2002 and highlights the adaptation techniques, which IDPs undertake to improve any provided shelter. Potential areas for improvement are indicated; for example, the possibility for using insulated, demountable liners to prevent cold-related deaths without sacrificing shelter flexibility along with the likely need for better agency coordination of the shelter responses they provide. The wider context in which the technical recommendations would be implemented must also be considered. Such issues include agency resources, political impediments to providing the desired option, and the preference of many IDPs that the best shelter would be their home. 相似文献
This paper explores the lessons learned by leaders in agricultural adaptation planning in order to assist other jurisdictions to develop adaptation strategies. It seeks to identify effective institutional, participatory and collaborative processes involved in designing agricultural adaptation strategies at the national and sub-national levels in Germany, Finland, the United Kingdom, the United States and Canada. Its methodology is based on review of agricultural adaptation policy documents, research initiatives, stakeholder engagement processes, and cross-sectoral collaborations as well as interviews with key informants such as leaders and actors in adaptation planning. The gathered data show that early adapters have an improved regional and national understanding of climatic impacts, and of the risks to agriculture before the initiation of the planning process. The results indicate that the interplay between bottom-up and top-down initiatives has been crucial in the development of adaptation strategies. The former has provided rich and robust participation in designing, implementing and monitoring adaptations, while the latter was important for prioritizing and legitimizing the development of strategy. It also provided access to high-level decision makers and funding. The results of the study suggest that fostering cross-sectoral collaborations—especially by focusing on broader questions such as the role of agriculture in society—has become an important part of adaptation planning. Finally, our results also stress that adaptation planning in agriculture could be enhanced by skills development and mutual learning across stakeholder groups, research and policy-makers, and through the ongoing interactive development of institutional capabilities. 相似文献
The proliferation of community-based collaborative approaches to public land management and planning has spawned many questions regarding issues of community representation and the effects of participation for local residents. This paper presents a longitudinal assessment of local resident participation in collaborative forest planning on local community–forest relations in southwestern Colorado. Using survey data of participants involved in the San Juan National Forest's forest plan revision community study groups from 1998 to 2003, we assess participation in terms of community representation and the effects of community-based collaboration upon individuals' forest uses, forest values, and the level and form of involvement in forest management and planning activities. Results show that community representation remains slanted towards existing active stakeholders, and that while forest values, uses, and frequencies of involvement change little, participants cite positive effects in terms of the development of new knowledge, personal relationships, and greater confidence to engage in forest management affairs. 相似文献
ABSTRACT: Several factors affect the occurrence and transport of pesticides in surface waters of the 29,400 km2 White River Basin in Indiana. A relationship was found between pesticide use and the average annual concentration of that pesticide in the White River, although this relationship varies for different classes of pesticides. About one percent of the mass applied of each of the commonly used agricultural herbicides was transported from the basin via the White River. Peak pesticide concentrations were typically highest in late spring or early summer and were associated with periods of runoff following application. Concentrations of diazinon were higher in an urban basin than in two agricultural basins, corresponding to the common use of this insecticide on lawns and gardens in urban areas. Concentrations of atrazine, a corn herbicide widely used in the White River Basin, were higher in an agricultural basin with permeable, well‐drained soils, than in an agricultural basin with less permeable, more poorly drained soils. Although use of butylate and cyanazine was comparable in the White River Basin between 1992 and 1994, concentrations in the White River of butylate, which is incorporated into soil, were substantially less than for cyanazine, which is typically applied to the soil surface. 相似文献
This paper describes the frustrating reality of sustainability implementation in the USA and New Zealand (NZ), an early adopter of sustainability mandates. Local government has a key role in implementation, but has been slow to uptake sustainable practices. We surveyed senior planners in small to medium-sized local government agencies in both countries to identify which features of local government support (or hinder) sustainability in practice.
Environmentally sustainable practices are not well entrenched in either country. In the USA, the framing of sustainability and public support are significant predictors of implementation. However, sustainability is rarely a priority. In NZ, local government capacity is the main driver of implementation. We recommend that planners promote sustainability values, reconcile economic development goals with sustainability (e.g., green economy model), and translate public support for sustainability into institutional priorities. NZ localities also need increased capacity and US localities need continued Federal and State support. 相似文献