Absorption cross-sections of atmospheric constituents: NO2, O2, and H2O

Absorption spectroscopy, which is widely used for concentration measurements of tropospheric and stratospheric compounds, requires precise values of the absorption cross-sections of the measured species. NO₂, O₂ and its collision-induced absorption spectrum, and H₂O absorption cross-sections have been measured at temperature and pressure conditions prevailing in the Earth’s atmosphere. Corrections to the generally accepted analysis procedures used to resolve the convolution problem are also proposed.     

Bacterial periphytic communities related to mercury methylation within aquatic plant roots from a temperate freshwater lake (South-Western France)

Environmental Science and Pollution Research - Macrophyte floating roots are considered as hotspots for methylmercury (MeHg) production in aquatic ecosystems through microbial activity....     

ISO 14001 registration: The process,the benefits,and the choice of registrar

This article introduces the concept of ISO 14001 registration, outlines related assessment processes, and reviews the drivers behind developing an ISO-14001-concordant environmental management system (EMS) and seeking third party registration of that EMS. It focuses on registration strategies for larger organizations and considerations in choosing a registrar, including: auditor qualifications, standards for the conduct of EMS audits, and some issues for audit and registration service providers. The authors conclude that it is beneficial to pursue an ISO-14001-concordant EMS and that the value of the system can be enhanced through registration. However, some thought should be given to choosing the appropriate registrar, in particular to their EMS and audit approaches and to the qualifications of their audit team. Service providers are also cautioned to remember that ISO 14001 is not the same as ISO 9000, and that the registrar's standard of care in the discharge of their work should reflect that. © 1998 John Wiley & Sons, Inc.     

Egg survival,embryonic development,and larval characteristics of northern shrimp (<Emphasis Type="Italic">Pandalus borealis</Emphasis>) females subject to different temperature and feeding conditions

Laboratory experiments on ovigerous females of northern shrimp (Pandalus borealis) were used to assess the effects of temperature and food ration on female condition during incubation and examine how combined effects of temperature and female condition influenced egg survival, embryonic development, and larval characteristics. Ovigerous females were maintained at 2°C, 5°C, and 8°C and fed on a low (three times/week; 2–2.7% W/W) or high ration (five times/week at satiation). The increase in temperature accelerated the developmental time of the eggs but their survival at 8°C was reduced. Conversion efficiency of yolk reserves in developing embryos was significantly reduced at elevated temperatures and larvae hatching at 2°C and 5°C were significantly larger and heavier than those hatching at 8°C. The experimental design did not result in any effect of food ration on the energetic condition of females or on egg characteristics and their biochemical composition. However, lower energy reserves were observed for females held at 8°C.     

Mother's body mass index as a predictor of infant's nutritional status in the post-emergency phase of a flood

Maternal nutritional status is a determinant of child health. This paper studies the association between a mother's body mass index (BMI) and her infant's nutritional status over a one year time frame after the 1998 flood crisis in Bangladesh. The paper uses secondary analysis of data collected from 757 households in seven rural areas of Bangladesh affected by the 1998 flood using multiple-stage probability sampling techniques (n = 143). Logistic regression models were employed to investigate the predictive impact of maternal BMI on infant's nutritional status after controlling for a range of child and maternal factors. An underweight mother was a significant factor with regard to the risk of infants suffering stunting (odds ratio (OR) = 4.45, 95 per cent confidence interval (CI) = 1.04-18.94) and being underweight (OR = 3.51, 95 per cent CI = 1.02-12.05) a year later, but not wasting (OR = 2.09, 95 per cent CI = 0.51-8.67). The findings suggest that there is a post-emergency link between maternal and infant nutritional health.     

Stoichiometric controls of nitrogen and phosphorus cycling in decomposing beech leaf litter

Resource stoichiometry (C:N:P) is an important determinant of litter decomposition. However, the effect of elemental stoichiometry on the gross rates of microbial N and P cycling processes during litter decomposition is unknown. In a mesocosm experiment, beech (Fagus sylvatica L.) litter with natural differences in elemental stoichiometry (C:N:P) was incubated under constant environmental conditions. After three and six months, we measured various aspects of nitrogen and phosphorus cycling. We found that gross protein depolymerization, N mineralization (ammonification), and nitrification rates were negatively related to litter C:N. Rates of P mineralization were negatively correlated with litter C:P. The negative correlations with litter C:N were stronger for inorganic N cycling processes than for gross protein depolymerization, indicating that the effect of resource stoichiometry on intracellular processes was stronger than on processes catalyzed by extracellular enzymes. Consistent with this, extracellular protein depolymerization was mainly limited by substrate availability and less so by the amount of protease. Strong positive correlations between the interconnected N and P pools and the respective production and consumption processes pointed to feed-forward control of microbial litter N and P cycling. A negative relationship between litter C:N and phosphatase activity (and between litter C:P and protease activity) demonstrated that microbes tended to allocate carbon and nutrients in ample supply into the production of extracellular enzymes to mine for the nutrient that is more limiting. Overall, the study demonstrated a strong effect of litter stoichiometry (C:N:P) on gross processes of microbial N and P cycling in decomposing litter; mineralization of N and P were tightly coupled to assist in maintaining cellular homeostasis of litter microbial communities.     

Combined use of pheromone trails and visual landmarks by the common garden ant Lasius niger

This study investigated the relative importance of pheromone trails and visual landmarks on the ability of Lasius niger foragers to relocate a previously used food source. Colonies formed foraging trails to a 1-M sucrose feeder. Sections of this trail were then presented back to the same colony after variable time intervals. Individual outgoing foragers were observed to determine if they walked for 15 cm in the direction of the feeder or not. On newly established pheromone trails formed by 500 ant passages, 77% of the foragers walked in the correct direction vs 31% for control foragers (no trail pheromone). Pheromone trails decayed to the control levels in 20–24 h. Trails formed with fewer ant passages (125 or 30) decayed quicker. The use of visual landmarks was investigated by using trails with outgoing foragers from the colony that established the trail, either in the same room or in a different room, with different visual landmarks, to that used during trail establishment. Approximately 20% more ants walked in the correct direction in the same room vs the different room. This difference decreased to around 10% 2 h after trail establishment, indicating that the ants in the different room were learning the new visual cues to navigate by. Our results show that visual landmarks and pheromone trails are approximately equally useful in initially guiding L. niger foragers to food locations and that these two information sources have a complementary function.     

The presence of females modulates the expression of a carotenoid-based sexual signal

Several environmental factors have been shown to shape the pattern of investment of carotenoids into the expression of sexual signals. Surprisingly, the impact of the social environment has been neglected. If a carotenoid-based sexual trait is used by females to choose a mate or by males to assess the quality of potential competitors for mates, males, in the presence of females, should upregulate expression of the trait. We tested this hypothesis in male zebra finches that were housed either with females or in a male-only social environment. Additionally, to investigate whether the social modulation of the expression of a sexual trait depends on the physiological need of carotenoids, we challenged half of the males with Escherichia coli lipopolysaccharide (LPS). We found that the social environment modulated the expression of bill color, with males kept in the presence of females harboring a redder bill at the end of the 3 weeks that the experiment lasted. Males injected with LPS showed duller bill color regardless of the presence of females, and social interactions with females result in upregulated bill color similarly for phosphate-buffered saline (PBS) and LPS males. Thus, social environment and immune activation had an additive effect on the expression of bill color. The effect of social environment on plasma carotenoids was less clear. Indeed, a first replicate of the entire experiment showed that both immune challenge and social context affected bill color, with a negative effect of immune challenge and a positive effect of the presence of females on circulating carotenoids. However, a second replicate of the experiment showed only a negative effect of the immune challenge. These results, therefore, suggest that the social environment can affect the expression of carotenoid-based sexual traits under both benign and carotenoid-demanding conditions. Whatever the signaling function of bill color (female mate choice or male–male competition for mates), the observed flexibility may be adaptive because the expression of the signal can be modulated depending on the expected rewards or costs associated with the presence or absence of females. Nevertheless, the mechanisms underlying such an effect are still unknown.