Impact of desiccation and heat exposure stress on Salmonella tolerance to acidic conditions

In a recent study, the pH of commonly used Salmonella pre-enrichment media became acidic (pH 4.0 to 5.0) when feed or feed ingredients were incubated for 24 h. Acidic conditions have been reported to injure or kill Salmonella. In this study, cultures of four known feed isolates (S. montevideo, S. senftenberg, S. tennessee, and S. schwarzengrund) and four important processing plant isolates (S. typhimurium, S. enteritidis, S. infantis, and S. heidelberg) were grown on meat and bone meal and later subjected to desiccation and heat exposure to stress the microorganism. The impact of stress on the isolates ability to survive in acidic conditions ranging from pH 4.0 to 7.0 was compared to the non-stressed isolate. Cell injury was determined on xylose lysine tergitol 4 (XLT4) and cell death determined on nutrient agar (NA). When measured by cell death in non-stressed Salmonella, S. typhimurium was the most acid tolerant and S. heidelberg was the most acid sensitive whereas in stressed Salmonella, S. senftenberg was the most acid tolerant and S. tennessee was the most acid sensitive. The pH required to cause cell injury varied among isolates. With some isolates, the pH required for 50% cell death and 50% cell injury was similar. In other isolates, cell injury occurred at a more neutral pH. These findings suggest that the pH of pre-enrichment media may influence the recovery and bias the serotype of Salmonella recovered from feed during pre-enrichment.     

Satellite telemetry reveals behavioural plasticity in a green turtle population nesting in Sri Lanka

Satellite transmitters were deployed on ten green turtles (Chelonia mydas) nesting in Rekawa Sanctuary (RS-80.851°E 6.045°N), Sri Lanka, during 2006 and 2007 to determine inter-nesting and migratory behaviours and foraging habitats. Nine turtles subsequently nested at RS and demonstrated two inter-nesting strategies linked to the location of their residence sites. Three turtles used local shallow coastal sites within 60 km of RS during some or all of their inter-nesting periods and then returned to and settled at these sites on completion of their breeding seasons. In contrast, five individuals spent inter-nesting periods proximate to RS and then migrated to and settled at distant (>350 km) shallow coastal residence sites. Another turtle also spent inter-nesting periods proximate to RS and then migrated to a distant oceanic atoll and made forays into oceanic waters for 42 days before transmissions ceased. This behavioural plasticity informs conservation management beyond protection at the nesting beach.     

There's nowhere to go: counting the costs of extreme weather to the homeless community

People experiencing homelessness are vulnerable to extreme weather in unique ways. The entrenched inequalities that underpin disaster vulnerability are compounded by extreme isolation and the stress of transient living on mental and physical health. However, the impacts of extreme weather on the homeless in Australia are largely undocumented and rarely incorporated in emergency planning. Interviews with and surveys of emergency and homeless services and service users revealed that the primary ramifications of losing shelter and worsening mental health deepen the cycle of homelessness and trauma. Consequently, homeless shelter losses, such as tents, should be included in pre‐ and post‐event impact statistics and subsequent recovery support. Extreme weather response plans should include early triggers and strategies for ‘non‐severe’ weather events, as the homeless community is affected earlier and by a wider range of meteorological conditions. Moreover, this study also explores the benefits of a trauma‐informed response to extreme weather when working with the homeless.     

Integrating managerial perceptions and transformational leadership into a work‐unit level model of employee involvement

Employee involvement is an organizational phenomenon that has received increasing empirical attention. Although much research has examined the outcomes of involvement at the organization level, arguments can be made for exploring involvement at the work‐unit level and for investigating the processes by which a unit‐level climate of involvement may be created or emerge. Building on largely untested suggestions that such processes are likely to be motivational and initiated by employees' immediate supervisors, this paper incorporates two concepts of managerial perceptions and leadership into a work‐unit level model of involvement climate. In particular, this study examines the indirect association of managerial perceptions about subordinates' ability to perform and about the utility of organizational practices for facilitating performance, as well as the direct association of transformational leadership, with a climate of involvement. The association of involvement climate with citizenship, absenteeism, and voluntary turnover is also considered. Using structural equation modeling in a sample of 167 work units, results indicate that leadership fully mediates the relationship between managers' perceptions about their subordinates and climate. Further, climate partially mediates and fully mediates the relationship between leadership and citizenship, and absenteeism, respectively. Implications for future research are discussed. Copyright © 2005 John Wiley & Sons, Ltd.     

Defended versus undefended home range size of carnivores,ungulates and primates

Summary We tested the hypothesis that undefended home ranges are larger than defended home ranges using data collected from the literature for three groups of mammals. A matched-pairs analysis of populations within species or species within genera showed that undefended home ranges were larger than defended home ranges for carnivores and male ungulates, but not for primates. Primates may have been an exception because they violated a key assumption of the hypothesis, that defence costs increase with the size of the defended area. Undefended home ranges were 5.4 and 15.2 times larger than defended home ranges for carnivores and male ungulates, respectively. Whether or not a home range is defended is an important source of variation that should be included in future studies of home range size. Correspondence to: J.W.A. Grant     

Effect of NOx control processes on mercury speciation in utility flue gas

The speciation of Hg in coal-fired flue gas can be important in determining the ultimate Hg emissions as well as potential control options for the utility. The effects of NOx control processes, such as selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR), on Hg speciation are not well understood but may impact emissions of Hg. EPRI has investigated the reactions of Hg in flue gas at conditions expected for some NOx control processes. This paper describes the methodology used to investigate these reactions in actual flue gas at several power plants. Results have indicated that some commercial SCR catalysts are capable of oxidizing elemental Hg in flue gas obtained from the inlets of SCR or air heater units. Results are affected by various flue gas and operating parameters. The effect of flue gas composition, including the presence of NH3, has been evaluated. The influence of NH3 on fly ash Hg reactions also is being investigated.     

Patterns of organochlorine pesticide contamination in neotropical migrant passerines in relation to diet and winter habitat

Eleven species of Neotropical migrant passerines collected in Illinois (USA) during May 1996, were analyzed for the presence of organochlorine (OC) pesticides. At least one of five OC pesticide residues was detected in 66 of 72 birds, representing all species examined. The contaminants most frequently detected were p,p'-DDE, dieldrin and heptachlor epoxide, all of which were present in the 10-30 ng/g range. Insectivores had significantly higher levels of these compounds than did non-insectivores, while there was no significant main effect of winter habitat (forest and scrub). Future research on OC pesticide contamination in resident New World passerines may allow more accurate predictions regarding the sources of contamination in Neotropical migrants.     

The gastropod statolith: a tool for determining the age of<Emphasis Type="Italic"> Nassarius reticulatus</Emphasis>

The microstructure, shape and appearance of the growth rings in statoliths of Nassarius reticulatus (L.) were investigated. This species possesses two statocysts, each containing a single spherical statolith of calcium carbonate of up to 0.22 mm in diameter in the largest animals. The relationship between statolith diameter (SD) and total shell height (TSH) is exponential [ln(TSH)=26.3SD–0.842], although the function is site specific. Statoliths of the largest whelks (>29 mm) contained three or four clearly defined rings, corresponding to TSH values of ~1.1, 4.6–5.3, 12.0–13.5 and 18.5 mm, respectively. The first ring likely represents the metamorphic ring that was deposited at the time of larval metamorphosis when the post-larval whelk adopted a benthic lifestyle. The estimated size of the whelks at formation of the second, third and fourth statolith rings closely matched the TSH inferred from the shell rings. It is concluded that the patterns of growth rings present in statoliths can provide information about the age and growth of N. reticulatus.Communicated by O. Kinne, Oldendorf/Luhe     

A new technique helps to uncover unknown peptides and disinfection by-products in water

正Environmental water samples can be extremely complex,with potentially thousands of molecules that can derive from natural organic matter(NOM)and thousands that derive from anthropogenic contaminants.As complex as these samples are,drinking water can be even more complex.Due to disinfectants that are used to treat drinking water(e.g.,chlorine,chloramines,