Assessment of Arsenic Losses during Ashing: A Comparison of Two Methods Applied to Atmospheric Participates

A comparison was made of over 300 pairs of arsenic results from instrumental neutron activation and flameless atomic absorption analyses of atmospheric particulates collected on glass fiber filters. Atomic absorption analyses involved low temperature ashing of filters at high power levels. No matrix modification chemicals were added to the acid extract which was analyzed. Neutron activation results are on the average 9% higher than those obtained by atomic absorption and the difference is statistically significant. This small difference is probably due to the analytical techniques or acid extraction and not in any important way to losses during low temperature ashing. This conclusion is in sharp contrast to other recently reported situations where low temperature ashing losses in analyzing atmospheric particulate were sizable. Although the atmospheres sampled differed somewhat between these situations the most obvious difference was in the combustibility of the filters used in sampling.     

Pre- and post-mating sexual selection both favor large males in a rainbowfish

Sexual selection can act through female choice and male–male competition. Although both processes can act simultaneously, they are typically studied independently. Here, we adopt a more integrated approach to studying sexual selection by incorporating measures of both processes using the western rainbowfish Melanotaenia australis, a freshwater fish endemic to northwestern Australia. We assessed male–male competition and female choice separately while measuring the performance of individual males under both processes and used paternity analyses to estimate male reproductive success. We then related the performance of males during each of these stages to their phenotype, which was described using linear measures of size and color pattern traits, and spectrographic measures of the reflectance of color patches. We found that female choice favored relatively large males and that these preferences were consistent within individual females and repeatable between different females. Larger males were also more dominant in the competition trials and sired the majority of offspring produced when females spawned. There was little evidence to suggest that sexual selection acted on male color patterns either via female choice or male contest competition or during subsequent post-mating episodes of sexual selection. We conclude, therefore, that male–male competition and female choice act concordantly to favor relatively large males and that these patterns of mating success are reflected during post-mating episodes of sexual selection.     

Management commitment to safety as organizational support: relationships with non-safety outcomes in wood manufacturing employees

INTRODUCTION: Employee perceptions of management commitment to safety are known to influence important safety-related outcomes. However, little work has been conducted to explore non-safety-related outcomes resulting from a commitment to safety. METHOD: Employee-level outcomes critical to the effective functioning of an organization, including attitudes such as job satisfaction and commitment to the organization, were included on surveys given to 641 hourly production employees at three wood products manufacturing facilities. Participants' were asked about perceptions of management commitment to safety and job-related variables such as perceived dangerousness of their position, organizational commitment, and withdrawal behaviors. Supervisors also rated the performance of each of their hourly subordinates. RESULTS: Results suggest that employee outcomes differ based on perceptions of management's commitment to safety. Specifically, management commitment to safety was positively related to job satisfaction, organizational commitment, and job-related performance. We also found a negative relationship between commitment to safety and employee withdrawal behaviors. CONCLUSIONS: Our results suggest that increasing employee perceptions of management's personal concern for employee well-being through a dedication to safety will result in positive outcomes beyond improved safety performance. These results also imply that there is a type of social exchange between employees and management that may affect employees similarly to perceived organizational support. IMPACT ON INDUSTRY: Results further reinforce the value of a commitment to safety by a firm's management. Organizations with a strong commitment to safety may enjoy not only a reduction in safety-related events but also increases in desirable employee attitudes and behaviors.     

Growth rate and hatching date in ostrich chicks reflect humoral but not cell-mediated immune function

A tradeoff between immune response and life history traits, in particular growth rate, has been documented in various bird species. Ostriches are fast-growing birds and a typical feature of cohorts is that offspring often differ greatly in size. We investigated the relationship between hatching date and growth rate of chicks and both cell-mediated (measured using a phytohaemagglutinin (PHA) injection) and humoral immune responses in ostrich chicks maintained on a research farm. Chicks with higher growth rates had intermediate responses to both diphtheria and tetanus toxoids. By contrast, no relation between growth rates and responses to PHA injection were found. We conclude that chick growth rate variation may be explained beyond a certain threshold by a tradeoff between the humoral response and growth. Both responses to PHA injection and humoral responses in chicks were found to decrease with chick hatching date. Within the context of ostrich farming, these results could partially explain size variations observed in cohorts of chicks, as well as high mortality rates during their first 3 months of age.     

PHYTOPLANKTON IN THE FOX CHAIN OF LAKES1

ABSTRACT: As part of a comprehensive water quality investigation on the Fox Chain of Lakes during May to October 1975, water samples from the Chain and Cedar Lake (reference) at 25 locations were collected weekly or bi-weekly to determine the species and densities of algae. The results have been evaluated for algal composition, density, and succession for each location. Sixty-four algal species were recovered from 414 samples. The number of species per sampling location varied from 10 at Channel Lake and Lake Marie to 26 on Fox Lake (main) and Grass Lake. Blue green algae were predominant and occurred at 25 of the 25 sampling stations. They consisted mainly of Aphanizomenon flos-aquae. The only flagellate of importance was Ceratium hirundinella, and significant concentrations of this organism were limited to Channel Lake and Lake Catherine. The only green alga bloom was created by Ulothrix variabilis on the waters of Pistakee Lake. Diatoms were quite significant on the shallower water bodies. Algal densities ranged from about 25 to 14,000 cts/ml. The highest count occurred on Mineola Bay. Other high counts (>10,000 cts/ml) observed were waters taken from Channel Lake, Grass Lake, and Fox Lake (main). In Grass Lake, 60 percent of the collections had algal densities in excess of 2,000 cts/ml. Most of these were the diatom Cyclotella meneghiniana.     

Beneath the Straw: In Defense of Participatory Adaptive Management

Our recent paper advocating adaptive management of invasive nonnative species (INS) in Kings Bay, Florida received detailed responses from both Daniel Simberloff, a prominent invasion biologist, and Mark Sagoff, a prominent critic of invasion biology. Simberloff offers several significant lines of criticism that compel detailed rebuttals, and, as such, most of this reply is dedicated to this purpose. Ultimately, we find it quite significant that Simberloff, despite his other stated objections to our paper, apparently agrees with our argument that proposals for alternative management of established INS (i.e., alternatives to minimization/eradication) should not be rejected on an a␣priori basis. We argue that more specific development and application of adaptive approaches toward INS management, whether in Kings Bay or other appropriate case studies, would be facilitated if ecosystem managers and invasion biologists follow Simberloff’s lead on this key point. While Sagoff largely shares (and, indeed, served as a primary source for developing) our general arguments that challenge common moral and scientific assumptions associated with invasion biology, he does question our suggestion that participatory adaptive management provides an appropriate framework for approaching environmental problems in which science and politics are inherently entangled. We attempt to answer this criticism through a brief sketch of what participatory adaptive management might look like for Kings Bay and how such an approach would differ from past management approaches.