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91.
Theory suggests that maternal effects are especially important in organisms with environmentally-sensitive sex-determining mechanisms. However, there is no substantive body of empirical evidence to confirm this conjecture. We integrated field and laboratory studies to jointly evaluate the significance of behavioral (nest-site choice) and physiological (yolk hormone allocation) maternal effects on offspring sex ratio in the common snapping turtle (Chelydra serpentina), a species with temperature-dependent sex determination (TSD). Of the 16 microhabitat variables measured, only three (south, east, and total overstory vegetation cover) were significantly correlated with nest temperature: cooler nests were located under more vegetation cover. In turn, these microhabitat predictors of nest temperature, and nest temperature itself, may influence nest sex ratio: shadier, cooler nests were more likely to produce a higher proportion of male offspring than less shady, warmer nests. Analysis of eggs from these same nests incubated in a common garden design in the laboratory revealed that clutch sex ratio was unaffected by levels of yolk estradiol, yolk testosterone, or their interaction. Examination of both behavioral and physiological maternal effects revealed no concordant impact on offspring sex ratio. However, eggs from nests that produced male-biased sex ratios in the field yielded higher proportions of males under constant-temperature conditions in the laboratory. Our study confirms the importance of behavioral maternal effects in nature on offspring sex ratios in species with TSD, while also revealing the potential presence of a predisposition for sex-ratio production underlying TSD in this system.Communicated by S. Krackow  相似文献   
92.
Objective: Increased numbers of people riding pedal cycles have led to a greater focus on pedal cycle safety. The aim of this article is to explore factors that are associated with fatal and a small number of serious-injury pedal cyclist crashes involving trucks that occurred in London between 2007 and 2011.

Methods: Data were collected from police collision files for 53 crashes, 27 of which involved a truck (≥3.5 tonnes) and a pedal cycle. A systematic case review approach was used to identify the infrastructure, vehicle road user, and management factors that contributed to these crashes and injuries and how these factors interacted.

Results: Trucks turning left conflicting with pedal cyclists traveling straight ahead was a common crash scenario. Key contributory factors identified included the pedal cyclists not being visible to the truck drivers, road narrowing, and inappropriate positioning of pedal cyclists.

Conclusions: Crashes involving trucks and pedal cyclists are complex events that are caused by multiple interacting factors; therefore, multiple measures are required to prevent them from occurring.  相似文献   

93.
Abstract

Due to vast research programmes of industrial countries during the last two decades, our knowledge about the intrinsic properties of nanomaterials has increased considerably. However, ‘nanoregulation’ lags behind this progress. Key elements of nanoregulation are definition/scope and safety/consumer information. Safety information along the nano life-cycle is vital for the nanoparticle producer down to the industrial downstream user (product producer). However, nanodeclaration (in the sense of a label on the product for consumers) is not yet widely spread, in different geographic regions for different reasons. This is a case study for the EU, Switzerland, Thailand, the USA, and Intergovernmental Organisations. In addition, this study investigates inter- and governmental activities and the relationship between nanodeclaration and WTO rules. Non-compliance with WTO rules is a pretext for not introducing nanodeclaration in products. It is concluded that WTO rules do not exclude nanodeclaration.  相似文献   
94.
Three methods (membrane filtration, multiple tube fermentation, and chromogenic substrate technology kits manufactured by IDEXX Laboratories, Inc.) are routinely used to measure indicator bacteria for beach water quality. To assess comparability of these methods, quantify within-laboratory variability for each method, and place that variability into context of variability among laboratories using the same method, 22 southern California laboratories participated in a series of intercalibration exercises. Each laboratory processed three to five replicates from thirteen samples, with total coliforms, fecal coliforms or enterococci measured depending on the sample. Results were generally comparable among methods, though membrane filtration appeared to underestimate the other two methods for fecal coliforms, possibly due to clumping. Variability was greatest for the multiple tube fermentation method. For all three methods, within laboratory variability was greater than among laboratories variability.  相似文献   
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Polychlorinated biphenyls (PCBs) and Polybrominated Diphenyls Ethers (PBDEs) are two highly lipophilic classes of persistent organic pollutants able to resist degradation and with the ability to bioaccumulate through the food chain. In Brazil, there are still few studies on PCBs and PBDEs in aquatic organisms. In this study, we determined the levels of PBDEs and PCBs in three different fish species from the Ilha Grande Bay, located in the southern state of Rio de Janeiro, Brazil. PBDEs levels were very low, with values below the limit of quantification. PCBs concentrations ranged from 2.29 to 27.60 ng g?1 ww in muscle and from 3.41 to 34.22 ng g?1 ww in liver of the three investigated fish species. Significant positive correlations were established between PCBs concentration and fish biometric variables in mullet (length and lipid content) and a statistically significant change between seasons in croaker was observed.  相似文献   
99.
An odor of unknown origin described as a “tar” or “asphalt” smell has become unbearable for many of Globeville, CO, residents over the past few years. Residents report during odor events burning eyes and throat, headaches, skin irritation, and problems sleeping. This study was undertaken to identify the potential sources of the odor and the concentrations of air pollutants making up the odor by conducting meteorological correlations and sampling for a panel of volatile organic compounds (VOCs), sulfur gases, and polycyclic aromatic hydrocarbons (PAHs) in the neighborhood and near suspected sources. Wind speed and direction data collected every 1 min in the neighborhood indicate that when the odor is noticed, the community is directly downwind of a wood preservation facility and an asphalt roofing facility. Air samples collected during high-intensity odor events have shown concentrations of methylene chloride, hexane, toluene, naphthalene, dibenz[a,h]anthracene, benzo[g,h,i]perylene, and indeno[1,2,3-cd]pyrene, each at least two times higher than background concentrations. Naphthalene and the other PAHs are known pollutants emitted from wood treatment processes, and are known to have a coal tar odor. Naphthalene was present in a sample collected directly adjacent to the Koppers facility and was not present in any background samples. Single-compound odor and health thresholds, however, were never surpassed. Given the technical and regulatory challenges of sampling odors and controlling emissions, it is recommended that Globeville residents and neighboring industry pursue a “good neighbor policy” to solve the odor issue. Specific offending industrial processes could be identified for which there exist cost-effective control technologies that would reduce exposure to odors and air toxics in Globeville.

Implications: Meteorological correlations and samples of volatile organic compounds (VOCs), sulfur gases, and polycyclic aromatic hydrocarbons (PAHs) in the Globeville, CO, neighborhood and near suspected sources during odor events indicate potential industrial sources of a transient and noxious odor. Legislative approaches have proven unfruitful and no health or odor thresholds were typically violated. New approaches are warranted to address odor mixture effects in neighborhoods near industrial facilities.  相似文献   
100.
The supply of freshwater to estuarine ecosystems is a critical factor in maintaining the overall health and organization of coastal marshes. Specifically along the Texas Gulf coast, the coupled effects of decreased freshwater inflows to the estuary and natural processes (e.g., precipitation, wind, and tides) can exert significant salt-stress on coastal marsh vegetation. In this project we sought to quantitatively link the inflow of freshwater to the estuary (San Antonio Bay) with Aransas National Wildlife Refuge (ANWR) coastal marsh salinity and assess the influence of salinity and inundation on Carolina wolfberry (Lycium carolinianum Walt.) phenology (leaf and fruit abundance). The Carolina wolfberry is one of the more common high marsh plant species found at ANWR and has been shown to be a key food source for endangered Whooping Cranes which inhabit the coastal marshes of the ANWR each fall/winter. Results from our study show that periods of decreased freshwater inflows to the estuary correlated with increased marsh salinity at the ANWR. Wolfberry plants at ANWR marsh sites displayed increased fruit abundance during years which had lower mean summer time salinity (June, July, and August) in San Antonio Bay; conversely, during years of increased bay salinity during the same summertime months, wolfberry plants showed decreased fruit abundance. Through the continued validation of the relationship between inflows and coastal marsh salinity, we hope to provide additional insight into how wolfberry phenology varies inter-annually across both salinity and inundation regimes and how freshwater inflows may affect food availability for the endangered Whooping Crane.  相似文献   
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