A novel method for quantifying the glossiness of animals

The glossy sheen of healthy hair is an ideal of human beauty; however, glossiness has never been quantified in the context of non-human animal signaling. Glossiness, the specular reflectance characteristic of polished surfaces, has the potential to act as a signal of quality because it depends upon material integrity and cleanliness. Here, we undertook two studies of glossiness in avian plumage to determine (a) the repeatability of a recently developed measure of glossiness, (b) the relationship between glossiness and conventional measures of coloration, and (c) how glossiness is associated with quality signaling. Using museum specimens of three North American bird species with glossy plumage (red-winged blackbird, Agelaius phoeniceus; great-tailed grackle, Quiscalus mexicanus; Chihuahuan raven, Corvus cryptoleucus), we found that the glossiness measure was highly repeatable for all species and was significantly correlated with plumage coloration (e.g., chroma, brightness) in male great-tailed grackles. We then used wild-caught grackles to examine sexual dimorphism in plumage glossiness and its correlation to a potentially sexually selected trait in this species, male tail length. We found that males were significantly glossier than females and that male, but not female, glossiness correlated positively with tail length. This study provides a repeatable method to measure glossiness and highlights its potential as a signal of individual quality in animals.     

non-lethal responses of the freshwater snail potamopyrgus antipodarum to dissolved arsenic

Two non-lethal responses, avoidance andimmobility, were observed for thefreshwater gastropod Potamopyrgusantipodarum on exposure to dissolvedarsenic (As) as arsenate (As(V)) orarsenite (As(III)). Two differentpopulations of P. antipodarum, onewith a long history of exposure todissolved As from geothermal fluids andthe other with minimal exposure, werecompared to test for adaptation to As. Both snail populations avoided dissolvedAs(III), the more toxic form, at lowerconcentrations than As(V). As(V), theless toxic form, was avoided by both snailpopulations at much lower concentrationsthan those at which the snails becameimmobile. In contrast, the concentrationsof As(III) which caused avoidance werealmost the same as those which causedimmobility, implying that avoidance may notbe an effective response to protect thesesnails from exposure to As(III). Snailsfrom the exposed population avoided As(V)at about 20% of the concentration thatwas avoided by the snails from theunexposed population. At higherconcentrations of As(V) which causedimmobility, this difference in sensitivitypersisted up to an exposure time of 48 hours. After 96 hours exposure, however,both populations showed similarsensitivity. Snails from the exposedpopulation were more sensitive to As(III),both avoiding the As and becoming immobileat lower concentrations than were observedfor the same responses in the snails fromthe unexposed population. We suggest thatthe differences in sensitivity between thetwo populations could have been the resultof the higher soft body As burden of theexposed snails at the start of thelaboratory experiments.     

Graduated driver licensing in the United States: evaluation results from the early programs

BACKGROUND: Seventeen states enacted graduated driver licensing (GDL) programs that were implemented from 1996 through 1999 and for which evaluations are of interest. METHODS: We received evaluation results reported for six states for which data were available. Summarizing results is difficult in other than the most global terms because of differences in pre-GDL programs, differences in GDL programs, and differences in evaluation methodology. RESULTS: All states identified some crash reduction among teen drivers following GDL implementation. This positive effect was observed across different geographic regions, and with different GDL programs. Simple counts are down-fewer teens are experiencing crashes and becoming injured. After calculating crash rates to adjust for changes over time in populations or licensed drivers, reductions generally were still found. Population-adjusted risks of injury/fatal crash involvement of 16-year-old drivers in Florida and Michigan were reduced by 11% and 24%, respectively. Population-adjusted risks of any crash involvement of 16-year-old drivers in Michigan and North Carolina were reduced by 25% and 27%, respectively. Reductions in night (restricted hours) crash risk were impressive in Florida, Michigan, and North Carolina. A comparison state design was only possible in the Florida evaluation, and results showed greater crash reductions under GDL. Change-point analyses of Michigan's crash data trends over time provided additional support of GDL's effectiveness in reducing crashes. DISCUSSION: Taken as a whole, and including the preliminary findings from California, Ohio, and Pennsylvania, these reports demonstrate the early effectiveness of GDL in reducing the crash risk of teen drivers. The impact of these studies and others to come will guide future research, practice, and policy.     

Evaluating the impact of passengers on the safety of older drivers

PROBLEM: This study involved a quasi-induced exposure analysis of 4 years of crashes involving older drivers in the state of Kentucky. METHOD: Single- and multivehicle crashes were disaggregated according to the number of passengers: (a) no passenger, (b) one passenger, and (c) two or more passengers. RESULTS: Overall, the presence of two or more passengers was found to negatively impact the probability that drivers 75 years of age or older were at fault in crashes. Several potential factors were studied for interactive effects with passengers: vehicle occupant gender mix, time of the day, road curvature, grade, and number of lanes. The negative impact of passengers increased for some geometric road conditions. However, older drivers were found to be safer at night when carrying two or more passengers. The presence or absence of passengers was not found to affect the 65- to 74-year-old driver group. Groups of male vehicle occupants with a 75+ male driver were found to have high single-vehicle crash rates. IMPACT: These results are among the first to directly consider the effect of passengers on the crash-causing propensity of older drivers and the findings suggest more work is warranted to consider causes for the crash rate differences.     

Influence of plant growth on degradation of linear alkylbenzene sulfonate in sludge-amended soil

Widespread application of sewage sludge to agricultural soils in Denmark has led to concern about the possible accumulation and effects of linear alkylbenzene sulfonate (LAS) in the soil ecosystem. Therefore, we have studied the uptake and degradation of LAS in greenhouse pot experiments. Sewage sludge was incorporated into a sandy soil to give a range from very low to very high applications (0.4 to 90 Mg dry wt. ha(-1)). In addition, LAS was added as water solutions. The soil was transferred to pots and sown with barley (Hordeum vulgare L. cv. Apex), rape (Brassica napus L. cv. Hyola 401), or carrot (Daucus carota L.). Also, plant-free controls were established. For all additions there was no plant uptake above the detection limit at 0.5 mg LAS kg(-1) d.w, but plant growth stimulated the degradation. With a growth period of 30 d, LAS concentrations in soil from pots with rape had dropped from 27 to 1.4 mg kg(-1) dry wt., but in plant-free pots the concentration decreased only to 2.4 mg kg(-1) dry wt. When LAS was added as a spike, the final concentration in soil from planted pots was 0.7 mg kg(-1) dry wt., but in pots without plants the final concentration was much higher (2.5 mg kg(-1) dry wt.). During degradation, the relative fraction of homologues C10, C11, and C12 decreased, while C13 increased.     

Effect of territory quality on intrusion rate in nonbreeding hummingbirds

Summary Experimental reductions of productivity on feeding territories of Anna's hummingbirds (Calypte anna) decreased intrusion rate. This trend contrasts with the absence of strong correlations between intrusion rate and productivity in previous experimental studies. Consideration of sample sizes, productivity rates, and time-dependent influences on intrusion rate (e. g., day-to-day changes in weather) indicates that this difference resulted from the more natural spatial distribution of artificial flowers used in this study. Offprint requests to: P.W. Ewald     

Fishery Enhancement Reef Building Exercise

The constructive use of coal-fired power station waste products for building artificial reefs is being explored for the first time in the U.K. at present, the practice of sea dumping of raw pulverised fuel ash (PFA) from coal combustion is under review and the use of consolidated PFA blocks offers a possible alternative. the planned fitting of flue gas desulphurisation (FGD) plant in the U.K. will additionally produce large quantities of gypsum. to test the environmental compatability of such materials in marine structures, an experimental reef has been constructed off the central south coast of the U.K. Fifty tonnes of blocks made from different combinations of PFA, gypsum, FGD waste water sludge, cement and gravel using standard concrete as the control material, were deployed. the site selected is remote from prominent sea bed features in an area of flat sand with limited species variety.The preliminary studies leading to the licensing of this project included bioassay experiments with diatom cultures, field trials with test tiles and trace metal bioaccumulation studies the stages of consultation and licensing of the project are outlined.

Colonisation of the reef has been rapid, initially by shoaling fish, particularly by bib (Trisopterus luscus) then, within the first month, by representatives of the commercial crab and lobster species typical of the local natural rocky coast. After three months the epifauna and flora were well established. at this stage some 80 species of flora and fauna have been identified in association with the reef with no differentiation in colonisation apparent between the PFA/gypsum mixtures and the concrete control. the number of species far exceeds that of PFA powder dumping grounds. Analyses for heavy metal ions in the reef blocks after 2 months immersion have not shown any significant difference from the original composition.     

Effect of Chlorination on the Gill Lipids of the Mussel Mytilus edulis (L)

Experiments are described which involve the chlorination of standard solutions of lipids and populations of the mussel, Mytilus edulis (L). The object was to test the hypothesis that chlorine will bind to unsaturated lipids. Evidence is presented that chlorine and aqueous chlorinated species rapidly and readily form addition compounds with unsaturated lipids in vivo as well as in vitro. The relevance of these findings to possible environmental effects of chlorination is discussed.