Synthesis of Common Management Concerns Associated with Dam Removal

Managers make decisions regarding if and how to remove dams in spite of uncertainty surrounding physical and ecological responses, and stakeholders often raise concerns about certain negative effects, regardless of whether these concerns are warranted at a particular site. We used a dam‐removal science database supplemented with other information sources to explore seven frequently raised concerns, herein Common Management Concerns (CMCs). We investigate the occurrence of these concerns and the contributing biophysical controls. The CMCs addressed are the following: degree and rate of reservoir sediment erosion, excessive channel incision upstream of reservoirs, downstream sediment aggradation, elevated downstream turbidity, drawdown impacts on local water infrastructure, colonization of reservoir sediments by nonnative plants, and expansion of invasive fish. Biophysical controls emerged for some of the concerns, providing managers with information to assess whether a given concern is likely to occur at a site. To fully assess CMC risk, managers should concurrently evaluate site conditions and identify the ecosystem or human uses that will be negatively affected if the biophysical phenomenon producing the CMC occurs. We show how many CMCs have one or more controls in common, facilitating the identification of multiple risks at a site, and demonstrate why CMC risks should be considered in the context of other factors such as natural watershed variability and disturbance history.     

The transformational potential of Nationally Appropriate Mitigation Actions in Tanzania: assessing the concept’s cultural legitimacy among stakeholders in the solar energy sector

While energy-sector emissions remain the biggest source of climate change, many least-developed countries still invest in fossil-fuel development paths. These countries generally have high levels of fossil-fuel technology lock-in and low capacities to change, making the shift to sustainable energy difficult. Tanzania, a telling example, is projected to triple fossil-fuel power production in the next decade. This article assesses the potential to use internationally supported Nationally Appropriate Mitigation Actions (NAMAs) to develop solar energy in Tanzania and contribute to transformational change of the electricity supply system. By assessing the cultural legitimacy of NAMAs among key stakeholders in the solar energy sector, we analyse the conditions for successful uptake of the concept in (1) national political thought and institutional frameworks and (2) the solar energy niche. Interview data are analysed from a multi-level perspective on transition, focusing on its cultural dimension. Several framings undermining legitimacy are articulated, such as attaching low-actor credibility to responsible agencies and the concept’s poor fit with political priorities. Actors that discern opportunities for NAMAs could, however, draw on a framing of high commensurability between experienced social needs and opportunities to use NAMAs to address them through climate-compatible development. This legitimises NAMAs and could challenge opposing framings.     

利用彗星实验检测丙烯酰胺对小鼠两种细胞的DNA损伤和修复

为了研究丙烯酰胺致小鼠睾丸细胞和外周血淋巴细胞DNA的损伤及修复情况,同时比较这两种细胞对丙烯酰胺的敏感性,将雄性昆明种小鼠一次性腹腔注射丙烯酰胺(50mg·kg-1(bw)),在暴露后第1、2、4、6、8、10、12d,分别对其睾丸组织细胞和外周血淋巴细胞DNA损伤进行彗星实验分析.结果表明,暴露结束后每个时间点小鼠睾丸组织细胞、外周血淋巴细胞DNA的迁移率均显著高于阴性对照组,随时间推移两种细胞DNA迁移距离逐渐降低,同一时间点睾丸组织细胞DNA损伤较外周血淋巴细胞DNA损伤更为严重,两者差异显著(p<0.05).以上结果表明,睾丸组织和外周血淋巴细胞可能是丙烯酰胺的作用位点;机体对丙烯酰胺造成的遗传损伤有一定的修复能力;与淋巴细胞相比,睾丸细胞对丙烯酰胺导致的遗传损伤更为敏感.     

Toxicity, dioxin-like activities, and endocrine effects of DDT metabolites—DDA, DDMU, DDMS, and DDCN

Background, aim, and scope  

2,2-bis(chlorophenyl)-1,1,1-trichloroethane (DDT) metabolites, other than those routinely measured [i.e., 2,2-bis(chlorophenyl)-1,1-dichloroethylene (DDE) and 2,2-bis(chlorophenyl)-1,1-dichloroethane (DDD)], have recently been detected in elevated concentrations not only in the surface water of Teltow Canal, Berlin, but also in sediment samples from Elbe tributaries (e.g., Mulde and Havel/Spree). This was paralleled by recent reports that multiple other metabolites could emerge from the degradation of parent DDT by naturally occurring organisms or by interaction with some heavy metals. Nevertheless, only very few data on the biological activities of these metabolites are available to date. The objective of this communication is to evaluate, for the first time, the cytotoxicity, dioxin-like activity, and estrogenicity of the least-studied DDT metabolites.     

Impact of withdrawal from market on the pattern of cyclooxygenase-2 inhibitors reported to Texas poison control centers

The cyclooxygenase-2 (COX-2) inhibitor rofecoxib was withdrawn from the US market on September 30, 2004, and valdecoxib was withdrawn on April 7, 2005. The impact of these actions on COX-2 inhibitor exposures reported to poison control centers was unknown. The objective of this study was to describe the pattern of COX-2 inhibitor exposures reported to Texas poison control centers before and after rofecoxib and valdecoxib were withdrawn. The number of celecoxib, rofecoxib, and valdecoxib exposures reported to Texas poison control centers each month during 1999–2006 was identified and examined for changes over time. Comparisons were made with respect to those exposures reported immediately prior to withdrawal (October 2003–September 2004) and to exposures after withdrawal (April 2005–December 2006). The mean monthly number of reported exposures prior to withdrawal was 18.8 for celecoxib, 20.3 for rofecoxib, 13.3 for valdecoxib, and 51.5 for total COX-2 inhibitors. The mean monthly number of reported exposures after withdrawal was 9.3 for celecoxib, 1.8 for rofecoxib, 1.3 for valdecoxib, and 12.3 for total COX-2 inhibitors, representing declines of 51, 91, 90, and 76%, respectively. The withdrawal of rofecoxib and valdecoxib from the market resulted in a decrease in the number of COX-2 inhibitor exposures reported to Texas poison control centers. However, rofecoxib and valdecoxib exposures continued to be reported for a long time after withdrawal. Reported celecoxib exposures declined even though it was not withdrawn from the market.     

Total release fogger exposures reported to Texas poison centers, 2000–2009

Total release foggers or “bug bombs” are products designed to fill an area such as a home or workplace with insecticide. Because of their method of action, unintentional exposures may occur. Cases for this retrospective study were all fogger exposures reported to Texas poison centers during 2000–2009. The distribution of cases was identified for various demographic and clinical factors. There were 2855 fogger exposures. Among the patients 56.0% were females and 69.5% were 20 years or older. Considering the exposure circumstances 95.6% were unintentional and 62.2% occurred through inhalation. The management site was 75.2% on site. The medical outcomes were no effect (11.8%), minor effect (25.1%), moderate effect (7.4%), major effect (0.1%), not followed (no effects expected) (3.5%), not followed (minimal effects expected) (39.3%), not followed (potentially toxic) (4.9%), and effects probably unrelated to exposure (7.7%). The most frequently reported clinical effects were cough (25.4%), vomiting (13.3%), nausea (9.2%), dyspnea (8.7%), throat irritation (7.9%), and headache (5.6%). The public needs to be educated about the potential hazard of exposures to foggers. However, most fogger exposures reported to poison centers are not likely to be seriously toxic and can be managed at home.     

企业文化与企业安全文化建设水平互动效应研究

为提高企业安全文化建设水平,基于人类协同国际环形和企业安全文化建设水平评价指标设计调查问卷,以赛轮金宇股份有限公司为研究对象,对其企业文化和企业安全文化建设水平进行相关性分析和多元逐步回归分析,探索二者的互动效应,从企业文化角度发掘安全文化建设重点。结果表明,自我实现文化、亲和文化、传统文化、成就文化与企业安全文化建设水平高度正相关,逃避文化则呈现高度负相关,其相关系数（绝对值）均在0.9以上;同时,多元逐步回归分析中,以上5个文化规则均进入回归方程,其标准化回归系数β分别为:0.395、0.182、0.169、0.129、-0.145。因此,这5种文化规则对企业安全文化建设水平具有很高的预测力,是企业安全文化建设的重点所在。     

Evaluating the effect of rainfall variability on vegetation establishment in a semidesert grassland

Of the operations required for reclamation in arid and semi-arid regions, establishing vegetation entails the most uncertainty due to reliance on unpredictable rainfall for seed germination and seedling establishment. The frequency of successful vegetation establishment was estimated based on a land surface model driven by hourly atmospheric forcing data, 7 years of eddy-flux data, and 31 years of rainfall data at two adjacent sites in southern Arizona, USA. Two scenarios differing in the required imbibition time for successful germination were evaluated—2 or 3 days availability of sufficient surface moisture. Establishment success was assumed to occur if plants could germinate and if the drying front in the soil did not overtake the growth of seminal roots. Based on our results, vegetation establishment could be expected to fail in 32 % of years. In the worst 10-year span, six of ten plantings would have failed. In the best 10-year span, only one of ten was projected to fail. Across all assessments, at most 3 years in a row failed and 6 years in a row were successful. Funding for reclamation seeding must be available to allow reseeding the following year if sufficient amount and timing of rainfall does not occur.     

Evidence for Changing Flood Risk in New England Since the Late 20th Century1

Abstract: Long‐term flow records for watersheds with minimal human influence have shown trends in recent decades toward increasing streamflow at regional and national scales, especially for low flow quantiles like the annual minimum and annual median flows. Trends for high flow quantiles are less clear, despite recent research showing increased precipitation in the conterminous United States over the last century that has been brought about primarily by an increased frequency and intensity of events in the upper 10th percentile of the daily precipitation distribution – particularly in the Northeast. This study investigates trends in 28 long‐term annual flood series for New England watersheds with dominantly natural streamflow. The flood series are an average of 75 years in length and are continuous through 2006. Twenty‐five series show upward trends via the nonparametric Mann‐Kendall test, 40% (10) of which are statistically significant (p < 0.1). Moreover, an average standardized departures series for 23 of the study gages indicates that increasing flood magnitudes in New England occurred as a step change around 1970. The timing of this is broadly synchronous with a phase change in the low frequency variability of the North Atlantic Oscillation, a prominent upper atmospheric circulation pattern that is known to effect climate variability along the United States east coast. Identifiable hydroclimatic shifts should be considered when the affected flow records are used for flood frequency analyses. Special treatment of the flood series can improve the analyses and provide better estimates of flood magnitudes and frequencies under the prevailing hydroclimatic condition.