Temperature responses vary between riffle beetles from contrasting aquatic environments.

Organisms living in environmentally stable ecosystems are hypothesized to exhibit narrow environmental tolerance ranges; however, previous experiments testing this prediction with invertebrates in spring habitats are equivocal. Here we examined the effects of elevated temperatures on four riffle beetle species (family: Elmidae) native to central and west Texas, USA. Two of these, Heterelmis comalensis and Heterelmis cf. glabra are known to occupy habitats immediately adjacent to spring openings and are thought to have stenothermal tolerance profiles. The other two, Heterelmis vulnerata and Microcylloepus pusillus are surface stream species with more cosmopolitan distributions and are assumed to be less sensitive to variation in environmental conditions. We examined performance and survival of elmids in response to increasing temperatures using dynamic and static assays. Additionally, changes in metabolic rate in response to thermal stress were assessed for all four species. Our results indicated that spring-associated H. comalensis is most sensitive while the more cosmopolitan elmid M. pusillus is least sensitive to thermal stress. However, there were differences in temperature tolerances among the two spring-associated species: H. comalensis had relatively narrow thermal tolerance in comparison to H. cf. glabra. This could be due to differences in the climatic and hydrological conditions in the geographical regions which the respective riffle beetle populations reside. However, despite these differences, H. comalensis and H. cf. glabra showed a dramatic increase in their metabolic rates with increasing temperatures indicating that these species are indeed spring specialists and likely have a stenothermal profile.

Effect of trophic position on mercury concentrations in bottlenose dolphins (Tursiops truncatus) from the northern Gulf of Mexico.

Marine species from the Gulf of Mexico often have higher mercury (Hg) concentrations than conspecifics in the Atlantic Ocean. Spatial differences in Hg sources, environmental conditions, and microbial communities influence both Hg methylation rates and the bioavailability of Hg to organisms at the base of the food web. Mercury bioaccumulates within organisms and biomagnifies in marine food webs, and therefore reaches the greatest concentrations in long-lived marine carnivores, such as dolphins. In this study, we explored whether differences in trophic position and foraging habitat among bottlenose dolphins (Tursiops truncatus) from the northern Gulf of Mexico (nGoM) contributed to the observed variation in skin total Hg (THg) concentrations. Using the δ13C and δ34S values in dolphin skin, we assigned deceased stranded dolphins from Florida (FL; n = 29) and Louisiana (LA; n = 72) to habitats (estuarine, barrier island, and coastal) east and west of the Mississippi River Delta (MRD). We estimated the mean trophic position of dolphins from each habitat using δ15N values from stranded dolphin skin and tissues of primary consumers taken from the literature following a Bayesian framework. Finally, we compared trophic positions and THg concentrations among dolphins from each habitat, accounting for sex and body length. Estimated marginal mean THg concentrations (µg/g dry weight) were greatest in dolphins assigned to the coastal habitat and estuarine habitats east of the MRD (range: 2.59-4.81), and lowest in dolphins assigned to estuarine and barrier island habitats west of the MRD (range: 0.675-0.993). On average, dolphins from habitats with greater THg concentrations also had higher estimated trophic positions, except for coastal dolphins. Our results suggest that differences in trophic positions and foraging habitats contribute to spatial variability in skin THg concentrations among nGoM bottlenose dolphins, however, the relative influence of these factors on THg concentrations are not easily partitioned.

Suicide Among the Emergency Medical Systems Occupation in the United States.

INTRODUCTION: Suicide claimed 47,173 lives in 2017 and is the second leading cause of death for individuals 15-34 years old. In 2017, rates of suicide in the United States (US) were double the rates of homicide. Despite significant research funding toward suicide prevention, rates of suicide have increased 38% from 2009 to 2017. Recent data suggests that emergency medical services (EMS) workers are at a higher risk of suicidal ideation and suicide attempts compared to the general public. The objective of this study was to determine the proportionate mortality ratio (PMR) of suicide among firefighters and emergency medical technicians (EMT) compared to the general US working population. METHODS: We analyzed over five million adult decedent death records from the National Occupational Mortality Surveillance database for 26 states over a 10-year non-consecutive period including 1999, 2003-2004, and 2007-2013. Categorizing firefighters and EMTs by census industry and occupation code lists, we used the underlying cause of death to calculate the PMRs compared to the general US decedent population with a recorded occupation. RESULTS: Overall, 298 firefighter and 84 EMT suicides were identified in our study. Firefighters died in significantly greater proportion from suicide compared to the US.working population with a PMR of 172 (95% confidence interval [CI], 153-193, P<0.01). EMTs also died from suicide in greater proportion with an elevated PMR of 124 (95% CI, 99-153), but this did not reach statistical significance. Among all subgroups, firefighters ages 65-90 were found to have the highest PMR of 234 (95% CI, 186-290), P<0.01) while the highest among EMTs was in the age group 18-64 with a PMR of 126 (95% CI, 100-156, P<0.05). CONCLUSION: In this multi-state study, we found that firefighters and EMTs had significantly higher proportionate mortality ratios for suicide compared to the general US working population. Firefighters ages 65-90 had a PMR more than double that of the general working population. Development of a more robust database is needed to identify EMS workers at greatest risk of suicide during their career and lifetime.

Interactions at surface-subterranean ecotones: structure and function of food webs within spring orifices.

Spring orifices are ecotones between surface and subterranean aquatic ecosystems. Invertebrates of different origins (e.g., surface, spring obligate, and subterranean) coexist in these spatially restricted environments, potentially competing for resources. However, processes that allow for population coexistence in these presumably low resource environments are not well understood. We examined invertebrate communities at two spring complexes in Texas, USA and assessed resource use and food web structure at spring orifices using stable isotopes of carbon (δ13C) and nitrogen (δ15N). Using bulk δ13C and δ15N of organisms and potential food sources, we elucidated dietary sources and found that invertebrate communities exhibited resource partitioning and contained two main food chains (periphyton versus terrestrial organic matter [OM]). In both spring complexes, several endemic spring orifice associated and subterranean taxa derived most of their diet from terrestrial OM. Analysis of compound-specific stable isotopes (i.e., δ13C of essential amino acids, EAAs) from two co-occurring elmid species indicated that the endemic spring orifice-associated species (Heterelmis comalensis) derived > 80% of its EAAs from bacteria, whereas the widespread surface species (Microcylloepus pusillus) derived its EAAs from a more equitable mix of bacteria, fungi, and algae. We additionally calculated niche overlap among of several taxonomically related groups (aquatic beetles and amphipods) that co-occur in spring ecotones and posterior probability estimates indicated little to no niche overlap among related species. Results indicate that invertebrates at subterranean-surface aquatic ecotones are partitioning food resources and highlight the importance of connections to riparian zones for persistence of several endemic invertebrates.

Relationship Between Methylmercury Contamination and Proportion of Aquatic and Terrestrial Prey in Diets of Shoreline Spiders.

Terrestrial organisms such as shoreline spiders that consume prey from aquatic food webs can be contaminated with methylmercury (MeHg). However, no studies have examined the relationship between MeHg contamination of shoreline spider taxa and the proportion of aquatic and terrestrial prey in their diets. The present study had 2 objectives: 1) determine concentrations of MeHg in 7 taxa of shoreline spiders, and 2) assess the relationship between concentrations of MeHg in spiders and the proportion of aquatic and terrestrial prey in spider diets. We collected shoreline spiders, emergent aquatic insects, and terrestrial insects from in and around 10 experimental ponds. Methylmercury concentrations were greatest in spiders, intermediate in aquatic insects, and lowest in terrestrial insects. The elevated MeHg concentrations in spiders indicate that they were feeding, at least in part, on emergent aquatic insects. However, variability in MeHg concentration observed among spider taxa suggested that the proportion of aquatic and terrestrial prey in spider diets likely varied among taxa. We estimated the proportion of aquatic and terrestrial prey in the diet of each spider taxon from the nitrogen (δ15 N) and carbon (δ13 C) isotope values of spiders and their potential aquatic and terrestrial prey items. The median proportion of aquatic prey in spider diets varied by almost 2-fold, and MeHg concentrations in shoreline spiders were strongly correlated with the proportion of aquatic prey in their diet. In the present study, we demonstrate for the first time that the degree of connectivity to aquatic food webs determines MeHg contamination of shoreline spiders. Environ Toxicol Chem 2019;38:2503-2508. © 2019 SETAC.

Chemolithoautotrophy supports macroinvertebrate food webs and affects diversity and stability in groundwater communities.

The prevailing paradigm in subterranean ecology is that below-ground food webs are simple, limited to one or two trophic levels, and composed of generalist species because of spatio-temporally patchy food resources and pervasive energy limitation. This paradigm is based on relatively few studies of easily accessible, air-filled caves. However, in some subterranean ecosystems, chemolithoautotrophy can subsidize or replace surface-based allochthonous inputs of photosynthetically derived organic matter (OM) as a basal food resource and promote niche specialization and evolution of higher trophic levels. Consequently, the current subterranean trophic paradigm fails to account for variation in resources, trophic specialization, and food chain length in some subterranean ecosystems. We reevaluated the subterranean food web paradigm by examining spatial variation in the isotopic composition of basal food resources and consumers, food web structure, stygobiont species diversity, and chromophoric organic matter (CDOM), across a geochemical gradient in a large and complex groundwater system, the Edwards Aquifer in Central Texas (USA). Mean δ13C values of stygobiont communities become increasingly more negative along the gradient of photosynthetic OM sources near the aquifer recharge zone to chemolithoautotrophic OM sources closer to the freshwater-saline water interface (FWSWI) between oxygenated freshwater and anoxic, sulfide-rich saline water. Stygobiont community species richness declined with increasing distance from the FWSWI. Bayesian mixing models were used to estimate the relative importance of photosynthetic OM and chemolithoautorophic OM for stygobiont communities at three biogeochemically distinct sites. The contribution of chemolithoautotrophic OM to consumers at these sites ranged between 25% and 69% of total OM utilized and comprised as much as 88% of the diet for one species. In addition, the food web adjacent to the FWSWI had greater trophic diversity when compared to the other two sites. Our results suggest that diverse OM sources and in situ, chemolithoautotrophic OM production can support complex groundwater food webs and increase species richness. Chemolithoautotrophy has been fundamental for the long-term maintenance of species diversity, trophic complexity, and community stability in this subterranean ecosystem, especially during periods of decreased photosynthetic production and groundwater recharge that have occurred over geologic time scales.

Bottom-up nutrient and top-down fish impacts on insect-mediated mercury flux from aquatic ecosystems.

Methyl mercury (MeHg) is one of the most hazardous contaminants in the environment, adversely affecting the health of wildlife and humans. Recent studies have demonstrated that aquatic insects biotransport MeHg and other contaminants to terrestrial consumers, but the factors that regulate the flux of MeHg out of aquatic ecosystems via emergent insects have not been studied. The authors used experimental mesocosms to test the hypothesis that insect emergence and the associated flux of MeHg from aquatic to terrestrial ecosystems is affected by both bottom-up nutrient effects and top-down fish consumer effects. In the present study, nutrient addition led to an increase in MeHg flux primarily by enhancing the biomass of emerging insects whose tissues were contaminated with MeHg, whereas fish decreased MeHg flux primarily by reducing the biomass of emerging insects. Furthermore, the authors found that these factors are interdependent such that the effects of nutrients are more pronounced when fish are absent, and the effects of fish are more pronounced when nutrient concentrations are high. The present study is the first to demonstrate that the flux of MeHg from aquatic to terrestrial ecosystems is strongly enhanced by bottom-up nutrient effects and diminished by top-down consumer effects.

Effects of fish on mercury contamination of macroinvertebrate communities of Grassland ponds.

Mercury is an environmental contaminant that negatively affects the health of vertebrate consumers such as fish, birds, and mammals. Although aquatic macroinvertebrates are a key link in the trophic transfer of Hg to vertebrate consumers, Hg contamination in macroinvertebrate communities has not been well studied. The purpose of the present study was to examine how Hg in macroinvertebrate communities is affected by the presence of fish. We sampled macroinvertebrates from five ponds with fish and five ponds without fish, at the Lyndon B. Johnson National Grassland in north Texas, USA. Ponds without fish contained a higher biomass of macroinvertebrates and taxa with higher concentrations of Hg, which led to a higher Hg pool in the macroinvertebrate community. A total of 73% of the macroinvertebrate biomass from ponds without fish was composed of taxa with the potential to emerge and transport Hg out of ponds into terrestrial food webs. The results of the present study suggest that small ponds, the numerically dominant aquatic ecosystems in the United States, may be more at risk for containing organisms with elevated Hg concentrations than has been appreciated.

Spatial variability in the speciation and bioaccumulation of mercury in an arid subtropical reservoir ecosystem.

Patterns of spatial variation of mercury and methylmercury (MeHg) were examined in sediments and muscle tissue of largemouth bass (Micropterus salmoides) from Amistad International Reservoir, a large and hydrologically complex subtropical water body in the Rio Grande drainage. The distributions of both Hg and MeHg were compared with environmental and biological factors known to influence production of MeHg. The highest concentrations of total Hg (THg) in sediment were found in the Rio Grande arm of the reservoir, whereas MeHg was highest at sites in the Devils River arm and inundated Pecos River (often more than 3.0 ng/g). Conditions in the sediments of the Devils River arm and Pecos River channel were likely more favorable to the production of MeHg, with higher sediment porewater dissolved organic carbon, and porewater sulfate levels in the optimal range for methylation. Although the detection of different groups of sulfate-reducing bacteria by polymerase chain reaction (PCR) was generally correlated with MeHg concentrations, bacterial counts via fluorescent in situ hybridization (FISH) did not correlate with MeHg. A sample of 156 largemouth bass (<30 cm) showed a spatial pattern similar to that of MeHg in sediments, where fish from the Devils River arm of the reservoir had higher muscle Hg concentrations than those collected in the Rio Grande arm. In 88 bass of legal sport fishing size (>35 cm), 77% exceeded the 0.3 mg/kg U.S. Environmental Protection Agency screening value. This study shows that significant variation in sediment MeHg and biotic Hg concentration can exist within lakes and reservoirs and that it can correspond to variation in environmental conditions and Hg methylation.

Prognostic utility of spontaneous erythroid colony formation and JAK2 mutational analysis for thrombotic events in essential thrombocythaemia.

BACKGROUND: Thrombotic events in essential thrombocythaemia (ET) are difficult to predict with current risk stratification based on age and prior history of thrombosis. AIMS: We aimed to assess the predictive value of the JAK2 V617F mutation (JAK2) and spontaneous erythroid colony (SEC) growth for the development of thrombotic events post diagnosis in patients with ET. METHODS: Consecutive patients with ET were retrospectively identified, and clinical and laboratory correlates were evaluated. Thrombotic events were categorized according to their occurrence at or prior to diagnosis (prior thrombosis), and any time post diagnosis of ET (subsequent thrombosis). JAK2 analysis was performed by allele-specific PCR on whole blood or bone marrow. RESULTS: A total of 62 patients was identified, median age 63 years; 67% (41/61) JAK2-positive and 47% (25/53) SEC-positive. Median follow-up was 33 months (range, 1 to 137). JAK2-positive patients showed a trend to increased prior thrombosis (27% vs 5%, P= 0.08), and a significant increase in the development of subsequent thrombosis (5-year event rate 31% vs 6%, P= 0.04), which persisted when stratified for a history of prior thrombosis (P= 0.04). Survival was not affected by JAK2 status. The SEC assay predicted an increased rate of baseline thrombosis (16% vs 0%, P= 0.04), but was not found to be predictive of any subsequent thrombotic events. CONCLUSIONS: Patients with ET who are JAK2-positive by whole blood allele-specific PCR appear to be at increased risk of thrombotic complications, which is independent of a prior history of thrombosis.

Mercury contamination of the fish community of a semi-arid and arid river system: spatial variation and the influence of environmental gradients.

Mercury (Hg) contamination of aquatic ecosystems is a global environmental problem. Data are abundant on Hg contamination and factors that affect its bioaccumulation in lake communities, but comparatively little information on riverine ecosystems exists. The present study examines fish Hg concentrations of the Lower Rio Grande/Rio Bravo del Norte drainage, Texas, USA and several of its major tributaries in order to assess whether spatial variation occurs in fish Hg concentrations in the drainage and if patterns of Hg contamination of fish are related to gradients in environmental factors thought to affect Hg concentrations in fish communities. Fish, invertebrates, sediments, and water quality parameters were sampled at 12 sites along the lower Rio Grande/Rio Bravo del Norte drainage multiple times over a one-year period. Spatial variation was significant in fish Hg concentrations when fish were grouped by literature-defined trophic guilds or as stable isotope-defined trophic levels, with highest concentrations found in the Big Bend region of the drainage. Mercury in fish in most trophic guilds and trophic levels were positively related to environmental factors thought to affect Hg in fish, including water column dissolved organic carbon (DOC) and sediment Hg concentrations. It is likely that fish Hg concentrations in the Big Bend region are relatively high because this section of the river has abundant geologic Hg sources and environmental conditions which may make it sensitive to Hg inputs (i.e., high DOC, variable water levels). Results from the present study indicate that Hg contamination of the Rio Grande/Rio Bravo del Norte has substantial implications for management and protection of native small-bodied obligate riverine fish, many of which are imperiled.

Comparing resource pulses in aquatic and terrestrial ecosystems.

Resource pulses affect productivity and dynamics in a diversity of ecosystems, including islands, forests, streams, and lakes. Terrestrial and aquatic systems differ in food web structure and biogeochemistry; thus they may also differ in their responses to resource pulses. However, there has been a limited attempt to compare responses across ecosystem types. Here, we identify similarities and differences in the causes and consequences of resource pulses in terrestrial and aquatic systems. We propose that different patterns of food web and ecosystem structure in terrestrial and aquatic systems lead to different responses to resource pulses. Two predictions emerge from a comparison of resource pulses in the literature: (1) the bottom-up effects of resource pulses should transmit through aquatic food webs faster because of differences in the growth rates, life history, and stoichiometry of organisms in aquatic vs. terrestrial systems, and (2) the impacts of resource pulses should also persist longer in terrestrial systems because of longer generation times, the long-lived nature of many terrestrial resource pulses, and reduced top-down effects of consumers in terrestrial systems compared to aquatic systems. To examine these predictions, we use a case study of a resource pulse that affects both terrestrial and aquatic systems: the synchronous emergence of periodical cicadas (Magicicada spp.) in eastern North American forests. In general, studies that have examined the effects of periodical cicadas on terrestrial and aquatic systems support the prediction that resource pulses transmit more rapidly in aquatic systems; however, support for the prediction that resource pulse effects persist longer in terrestrial systems is equivocal. We conclude that there is a need to elucidate the indirect effects and long-term implications of resource pulses in both terrestrial and aquatic ecosystems.

Allochthonous subsidy of periodical cicadas affects the dynamics and stability of pond communities.

Periodical cicadas emerge from below ground every 13 or 17 years in North American forests, with individual broods representing the synchronous movement of trillions of individuals across geographic regions. Due to predator satiation, most individuals escape predation, die, and become deposited as detritus. Some of this emergent biomass falls into woodland aquatic habitats (small streams and woodland ponds) and serves as a high-quality allochthonous detritus pulse in early summer. We present results of a two-part study in which we (1) quantified deposition of Brood X periodical cicada detritus into woodland ponds and low-order streams in southwestern Ohio, and (2) conducted an outdoor mesocosm experiment in which we examined the effects of deposition of different amounts of cicada detritus on food webs characteristic of forest ponds. In the mesocosm experiment, we manipulated the amount of cicada detritus input to examine if food web dynamics and stability varied with the magnitude of this allochthonous resource subsidy, as predicted by numerous theoretical models. Deposition data indicate that, during years of periodical cicada emergence, cicada carcasses can represent a sizable pulse of allochthonous detritus to forest aquatic ecosystems. In the mesocosm experiment, cicada carcass deposition rapidly affected food webs, leading to substantial increases in nutrients and organism biomass, with the magnitude of increase dependent upon the amount of cicada detritus. Deposition of cicada detritus impacted the stability of organism functional groups and populations by affecting the temporal variability and biomass minima. However, contrary to theory, stability measures were not consistently related to the size of the allochthonous pulse (i.e., the amount of cicada detritus). Our study underscores the need for theory to further explore consequences of pulsed allochthonous subsidies for food web stability.

Public honour, private shame and HIV: issues affecting sexual health service delivery in London's South Asian communities.

Within a wider discussion of health service provision for black and minority ethnic (BME) groups, this paper considers how socio-cultural factors affect the provision of HIV and sexual health services to South Asians in London. It argues that communally held concepts of honour and shame within South Asian communities create a framework of social control with significant implications for HIV/AIDS transmission. It examines the provision of culturally sensitive services to BME communities by ethnically specific and generic service providers through a case study of the Naz Project London. Finally, it proposes an agenda for future research into BME sexual health service provision.

The Patient Care Notebook: quality improvement on a rehabilitation unit.

BACKGROUND: Shortened lengths of stay in acute and rehabilitation hospitals, continuing financial pressures on all postacute care services, and increasing out-of-pocket health care costs for patients and families challenge rehabilitation hospitals' patient education and discharge planning processes. Spaulding Rehabilitation Hospital (Boston) introduced a patient care notebook in a 15-bed satellite unit and pilot tested its contribution to the patient education and discharge planning process. DEVELOPING THE NOTEBOOK: The three-ring binder notebook included sections on medical appointments and phone numbers, understanding illness and medical care, coping with illness, physical activities, recommendations for the home, and community resources, with both standard and patient-specific information. RESULTS: Most of the patients and caregivers who received the notebooks found them to be helpful, and most staff indicated that the notebook improved the teaching process. Telephone calls to the unit after home discharges decreased form 28 calls for 11 discharges to 6 calls for 21 discharges after the notebook began to be used regularly. DISCUSSION: Staff felt that the process of using the notebook helped focus attention on teaching during the entire course of a patient's hospitalization rather than just a day or two before discharge. The patient care notebook process is being introduced to the entire hospital and to all patients, regardless of discharge location and the patient's literacy or proficiency with English. CONCLUSION: In using the notebook, the QI team, and the entire unit staff, learned about the complexities of QI, patient education, and discharge planning. The notebook process was implemented throughout the hospital a little more than a year after the completion of the pilot project.

Children's attributions about family arguments: implications for family therapy.

Children's attributions about the causes of family arguments affect both their interpretations of the meaning of and their adjustment to such events. Children's attributions about family arguments are, therefore, of importance in family therapy, especially for therapists who work from a cognitive or constructivist perspective. In an exploratory study, we examined children's attributions about family arguments in two arenas: marital arguments and parent-child arguments. Ninety-two children, aged 5-12, listened to an audiotaped argument and answered a series of structured questions concerning different attributions about the causes of such arguments. Descriptive analyses of the most and least endorsed attributions provided an overall map of the "stories" children tell about the causes of family arguments, and showed that, in general, they are more likely to endorse multiple, interacting causes than internal, blaming attributions. Additionally, children of all ages made somewhat different attributions concerning mothers vs. fathers in marital arguments. Implications for family therapy and suggestions for future clinical research are discussed.

Dihydropyrancarboxamides related to zanamivir: a new series of inhibitors of influenza virus sialidases. 1. Discovery, synthesis, biological activity, and structure-activity relationships of 4-guanidino- and 4-amino-4H-pyran-6-carboxamides.

4-Amino- and 4-guanidino-4H-pyran-6-carboxamides 4 and 5 related to zanamivir (GG167) are a new class of inhibitors of influenza virus sialidases. Structure--activity studies reveal that, in general, secondary amides are weak inhibitors of both influenza A and B viral sialidases. However, tertiary amides, which contain one or more small alkyl groups, show much greater inhibitory activity, particularly against the influenza A virus enzyme. The sialidase inhibitory activities of these compounds correlate well with their in vitro antiviral efficacy, and several of the most potent analogues displayed useful antiviral activity in vivo when evaluated in a mouse model of influenza A virus infection. Carboxamides which were highly active sialidase inhibitors in vitro also showed good antiviral activity in the mouse efficacy model of influenza A infection when administered intranasally but displayed modest activity when delivered by the intraperitoneal route.