Characterization of dioxin exposure in firefighters, residents, and chemical workers in the Irkutsk Region of Russian Siberia

The goal of this study was to characterize body burdens of polychlorinated dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) in three groups of Siberians living in the Irkutsk Region of Russia. These groups included firefighters exposed to a mixture of toxic substances extinguishing a large fire at the Shelekhovo Cable Factory in 1992, chemical workers from the Khimprom chemical plant, and residents living in proximity to large chemical factories in Sayansk and Angarsk. Blood samples from all groups were obtained in the fall of 1998. Dioxin analyses of samples were performed in Germany, Canada, and in a Russian dioxin laboratory in Ufa, Bashkortostan Republic. The average levels of dioxin toxic equivalents (TEQs) are 23.6 parts per trillion (ppt) total TEQ (PCDD/F only) in the disabled firefighters, 25.0 in the non-disabled firefighters, 28.7 in residents, and 45.6 in the Khimprom workers blood. Two workers did have elevated total TEQs of 91.4 and 102.2 ppt. Dibenzofurans and coplanar PCBs substantially contribute to the total elevated TEQ seen here. The average TEQs suggest levels of dioxin exposure in this part of the former Soviet Union not dissimilar to levels measured in industrialized countries of Europe and Northern America.     

The role of synchronized calling,ambient light,and ambient noise,in anti-bat-predator behavior of a treefrog

Summary Male treefrogs, Smilisca sila (Hylidae), produce calls of varying complexity and demonstrate a remarkable ability to synchronize their calls with those of neighbors. The bat Trachops cirrhosus eats frogs and uses the frogs' advertisement calls as locational cues. The bats are less likely to respond to synchronous calls than to asynchronous calls, and when given a choice prefer complex calls to simple calls.Experiments with bat models indicate that, like other frogs, S. sila probably uses visual cues to detect hunting bats. In response to bat models the frogs decreased both the number and the complexity of their calls. The calling behavior of the frogs was sampled in the field during periods with and without artificial illumination. The frogs produced fewer and less complex calls, and they tended to call from more concealed sites, during the period without illumination, when presumably it would have been more difficult for the frogs to detect hunting bats. S. sila tended to call from sites with higher ambient noise level, the noise primarily originating from waterfalls. The frequencies of the dominant energies in the waterfall sounds completely overlapped the frequency range of the S. sila call; thus waterfalls might mask the frog calls. When given a choice between calls produced near and away from waterfall sounds, bats preferred the latter.     

Finding upper-level sets in cellular surface data using echelons and saTScan

Across a spectrum of contemporary contexts from public health to landscape ecology and natural resources, there is need for objective determination of elevated occurrence in phenomena such as disease incidence and biodiversity. Occurrences of such phenomena constitute response surfaces, but data regarding the surface is typically acquired in a cellular framework. The cells may comprise a regular grid, or may be of irregular shapes such as counties in which statistics are collected. Echelons are a topologically based approach to systematic determination of spatial structure in a step surface. Spatial scan statistics are a probability-based approach to the same issue when interest lies in a rate variable. Here we examine the use of echelons both separately and in conjunction with the SaTScan implementation of spatial scan statistics for purposes of determination and visualization of upper-level sets. Consideration is given to both conventional geographic space and to the cellular pseudo-space of contingency tables for ordered categorical variables. Received: August 2002 / Revised: July 2005     

No evidence for female mate choice based on genetic similarity in the túngara frog Physalaemus pustulosus

In most sexually reproducing animals, the behavior of one or both sexes during courtship critically influences the success at mating of the opposite sex. This behavior is often interpreted as “mate choice,” and there is great interest in why such choices are exercised. The explanation for the evolution of mate choice that has received the most attention and generated the most controversy is based on assumed genetic effects. In this study, we investigated whether female túngara frogs, which choose mates based on acoustic cues, have a preference for genetically less related males. Specifically, we determine if there is disassortive mating based on microsatellite markers, if there is information in the advertisement call that could be used to assess genetic similarity, and if females exhibit acoustic-based mating preferences that would promote choice for genetic diversity. Using seven microsatellite markers, we found no correlation of male call similarity and male genetic relatedness. Female choice experiments showed no female preference for calls of less related males, and there was no evidence for inbreeding avoidance in the field. Our results do not support the hypothesis of mate choice based on information about genetic relatedness conveyed by acoustic signals in túngara frogs.     

A Comparison of Three Methods to Collect Submerged Aquatic Vegetation in a Shallow Lake

Two boat-based and one in-water sampling method have been used to collect submerged aquatic vegetation (SAV) as part of a long-term monitoring program in Lake Okeechobee, Florida, USA. The boat-based methods consisted of collecting SAV with a ponar dredge, used only to collect Chara, and an oyster tongs-like rake apparatus, used to collect all SAV. The in-water method involved use of a 0.5 m² PVC quadrat frame deployed by a diver. During summer 2002, SAV biomass samples were collected using all three methods at various sites in the lake to compare between-methods sampling precision. Sites used for these comparisons were selected based on plant type, plant density and sediment type. Statistical comparisons indicated that there were significant (p ≤ 0.05) biomass differences in 8 of 15 possible pairwise comparisons between sampling method biomass means. In four of the eight comparisons, significantly higher biomass mean values were obtained using the quadrat frame. In three of the remaining four comparisons, significantly higher biomass mean values were obtained with the rake apparatus. For the fourth comparison, a significantly higher biomass mean value was obtained with the ponar dredge. Three of the four relationships between SAV biomass collected by the rake and the quadrat and the rake and the quadrat/ponar dredge were statistically significant, linear and explained between 67 and 78% of the biomass variability. There were no significant differences between regression coefficients or elevations for these relationships, therefore these regressions estimated the same population regression. The population regression coefficient was 0.95, suggesting that the quadrat and ponar over-sampled relative to the rake, but the amount of this over-sampling was very small. Since there was no consistent pattern in the sampling method which yielded the significantly different biomass values and there were no significant differences in sampling precision across a range of plant species, plant densities and two sediment types, the boat-based rake method appears to be a suitable replacement for the previously used ponar dredge and quadrat methods, when in-lake measurements are not practical.     

Understanding the Large‐Scale Influence of Levees on Floodplain Connectivity Using a Hydrogeomorphic Approach

The widespread construction of levees has reduced river–floodplain connectivity and altered associated fluvial processes in many river systems. Despite the recognition that levees can alter floodplain connectivity, few studies have examined the role of levees in reducing floodplain areas at large watershed scales. This paper explores the application of a hydrogeomorphic floodplain inundation model in the Wabash Basin, located in the Midwestern United States, to assess changes in floodplain area in levee‐protected areas. We evaluate 10‐ and 30‐m topographic resolutions and spatially examine the influence of levees on floodplain area in relation to river network attributes. Generally, floodplains in levee‐protected areas were influenced by topographic resolution, stream order, and elevation details of levees found in topography datasets. We show, when compared to Federal Emergency Management Agency maps, our approach underpredicts floodplain area when using 10‐m resolution topography data but only slightly overpredicts when using 30‐m resolution data. After removing details of levees from topography data, we found changes in floodplain area varied spatially, but basin‐aggregate results changed little compared to topography datasets that contain levees, though larger floodplain areas were produced in some regions where levees were removed. This work contributes to a growing research emphasis on using hydrogeomorphic floodplain models to understand floodplain disconnectivity.     

Using Steady‐State Backwater Analysis to Predict Inundated Area from National Water Model Streamflow Simulations

National Water Model (NWM) simulates the hydrologic cycle and produces streamflow forecasts for 2.7 million reaches in the National Hydrography Dataset for continental United States (U.S.). NWM uses Muskingum–Cunge channel routing, which is based on the continuity equation. However, the momentum equation also needs to be considered to obtain more accurate estimates of streamflow and stage in rivers, especially for applications such as flood‐inundation mapping. Here, we used a steady‐state backwater version of Simulation Program for River NeTworks (SPRNT) model. We evaluated SPRNT’s and NWM’s abilities to predict inundated area for the record flood of Hurricane Matthew in October 2016. The Neuse River experienced record‐breaking floods and was well‐documented by U.S. Geological Survey. Streamflow simulations from NWM retrospective analysis were used as input for the SPRNT simulation. Retrospective NWM discharge predictions were converted to stage. The stages (from both SPRNT and NWM) were utilized to produce flood‐inundation maps using the Height Above Nearest Drainage method which uses the local relative heights to find out the local draining potentials and provide spatial representation of inundated area. The inundated‐area accuracies for NWM and SPRNT (based on comparison to a remotely sensed dataset) were 65.1% and 67.6%, respectively. These results show using steady‐state SPRNT results in a modest improvement of inundation‐forecast accuracy compared to NWM.     

Evaluation of developmental metrics for utilization in a pediatric advanced automatic crash notification algorithm

Objective: Appropriate treatment at designated trauma centers (TCs) improves outcomes among injured children after motor vehicle crashes (MVCs). Advanced Automatic Crash Notification (AACN) has shown promise in improving triage to appropriate TCs. Pediatric-specific AACN algorithms have not yet been created. To create such an algorithm, it will be necessary to include some metric of development (age, height, or weight) as a covariate in the injury risk algorithm. This study sought to determine which marker of development should serve as a covariate in such an algorithm and to quantify injury risk at different levels of this metric.

Methods: A retrospective review of occupants age < 19 years within the MVC data set NASS-CDS 2000–2011 was performed. R² values of logistic regression models using age, height, or weight to predict 18 key injury types were compared to determine which metric should be used as a covariate in a pediatric AACN algorithm. Clinical judgment, literature review, and chi-square analysis were used to create groupings of the chosen metric that would discriminate injury patterns. Adjusted odds of particular injury types at the different levels of this metric were calculated from logistic regression while controlling for gender, vehicle velocity change (delta V), belted status (optimal, suboptimal, or unrestrained), and crash mode (rollover, rear, frontal, near-side, or far-side).

Results: NASS-CDS analysis produced 11,541 occupants age < 19 years with nonmissing data. Age, height, and weight were correlated with one another and with injury patterns. Age demonstrated the best predictive power in injury patterns and was categorized into bins of 0–4 years, 5–9 years, 10–14 years, and 15–18 years. Age was a significant predictor of all 18 injury types evaluated even when controlling for all other confounders and when controlling for age- and gender-specific body mass index (BMI) classifications. Adjusted odds of key injury types with respect to these age categorizations revealed that younger children were at increased odds of sustaining Abbreviated Injury Scale (AIS) 2+ and 3+ head injuries and AIS 3+ spinal injuries, whereas older children were at increased odds of sustaining thoracic fractures, AIS 3+ abdominal injuries, and AIS 2+ upper and lower extremity injuries.

Conclusions: The injury patterns observed across developmental metrics in this study mirror those previously described among children with blunt trauma. This study identifies age as the metric best suited for use in a pediatric AACN algorithm and utilizes 12 years of data to provide quantifiable risks of particular injuries at different levels of this metric. This risk quantification will have important predictive purposes in a pediatric-specific AACN algorithm.     

Bisphenol A exposure alters release of immune and developmental modulators and expression of estrogen receptors in human fetal lung fibroblasts

Bisphenol A(BPA) has been shown to exert biological effects through estrogen receptor(ER)-dependent and ER-independent mechanisms. Recent studies suggest that prenatal exposure to BPA may increase the risk of childhood asthma. To investigate the underlying mechanisms in the actions of BPA, human fetal lung fibroblasts(h FLFs) were exposed to varying doses of BPA in culture for 24 hr. Effects of BPA on localization and uptake of BPA,cell viability, release of immune and developmental modulators, cellular localization and expression of ERα, ERβ and G-protein coupled estrogen receptor 30(GPR30), and effects of ERs antagonists on BPA-induced changes in endothelin-1(ET-1) release were examined.BPA at 0.01–100 μmol/L caused no changes in cell viability after 24 hr of exposure. h FLFs expresses all three ERs. BPA had no effects on either cellular distribution or protein expression of ERα, however, at 100 μmol/L(or 23 μmol/L intracellular BPA) increased ERβprotein levels in the cytoplasmic fractions and GPR 30 protein levels in the nuclear fractions.These paralleled with increased release of growth differentiation factor-15, decreased phosphorylation of nuclear factor kappa B p65 at serine 536, and decreased release of ET-1,interleukin-6, and interferon gamma-induced protein 10. ERs antagonists had no effects on BPA-induced decrease in ET-1 release. These data suggest that BPA at 100 μmol/L altered the release of immune and developmental modulators in h FLFs, which may negatively influence fetal lung development, maturation, and susceptibility to environmental stressors, although the role of BPA in childhood asthma remains to be confirmed in in vivo studies.     

Prediction of dioxin/furan incinerator emissions using low-molecular-weight volatile products of incomplete combustion

Emissions of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/Fs) from incinerators and other stationary combustion sources are of environmental concern because of the toxicity of certain PCDD/F congeners. Measurement of trace levels of PCDDs/Fs in combustor emissions is not a trivial matter. Development of one or more simple, easy-to-measure, reliable indicators of stack PCDD/F concentrations not only would enable incinerator operators to economically optimize system performance with respect to PCDD/F emissions, but could also provide a potential technique for demonstrating compliance status on a more frequent basis. This paper focuses on one approach to empirically estimate PCDD/F emissions using easy-to-measure volatile organic C2 chlorinated alkene precursors coupled with flue gas cleaning parameters. Three data sets from pilot-scale incineration experiments were examined for correlations between C2 chlorinated alkenes and PCDDs/Fs. Each data set contained one or more C2 chloroalkenes that were able to account for a statistically significant fraction of the variance in PCDD/F emissions. Variations in the vinyl chloride concentrations were able to account for the variations in the PCDD/F concentrations strongly in two of the three data sets and weakly in one of the data sets.