Greenhouse gas emissions along the rural-urban gradient

This paper investigates how land use relates to greenhouse gas emissions, using data sources that are readily available to municipal planners. It presents a causal framework linking settlement patterns to greenhouse gas emissions via landscape impacts (deforestation, carbon sequestration by soils and plants, urban heat island), infrastructure impacts (transportation-related emissions, waste management-related emissions, electric transmission and distribution losses) and buildings (residential, commercial). This is not a full accounting because it does not include impacts from industrial activities, agriculture and consumer behavior not related to land use, such as food consumption and air travel. Exploratory case studies of municipalities lying along a gradient of increasing population density suggest that per-capita carbon dioxide emissions vary widely, following an inverted ‘U’ shape, with post-war suburbs riding the pinnacle. Reflecting their central regional roles, municipalities with good jobs-to-housing ratios have higher per-capita emissions because they host both residential and commercial buildings. Buildings typically contribute more emissions than personal transportation. Vehicle-miles traveled per capita shrink most dramatically at very high population densities and where transit options exist. Changing land-use patterns is a political challenge because localism and outdated zoning ordinances subvert regional solutions. Technical fixes, especially green buildings, must be part of the solution.     

Discriminating among organizational politics,justice, and support

The discriminant validity of perceptions of organizational politics, organizational support, and procedural and distributive justice was examined as the distinctions between these variables have been blurred in past research. Results from a sample of 418 full‐time employees provided evidence of discriminant validity for these variables. First, structural equation modelling was used to isolate the best structural representation of these four variables. Then, six theoretically relevant predictors (i.e., leader–member exchange, centralization, formalization, co‐worker cooperation, role conflict, and locus of control) were examined in an effort to provide further conceptual separation. Five of the six antecedents distinguished among politics, justice, and support. Suggestions for additional research that can shed light on the distinctions and similarities of these variables are offered based on the results of this study. Copyright © 2001 John Wiley & Sons, Ltd.     

Dispersal, density dependence, and population dynamics of a fungal microbe on leaf surfaces

Despite the ubiquity and importance of microbes in nature, little is known about their natural population dynamics, especially for those that occupy terrestrial habitats. Here we investigate the dynamics of the yeast-like fungus Aureobasidium pullulans (Ap) on apple leaves in an orchard. We asked three questions. (1) Is variation in fungal population density among leaves caused by variation in leaf carrying capacities and strong density-dependent population growth that maintains densities near carrying capacity? (2) Do resident populations have competitive advantages over immigrant cells? (3) Do Ap dynamics differ at different times during the growing season? To address these questions, we performed two experiments at different times in the growing season. Both experiments used a 2 x 2 factorial design: treatment 1 removed fungal cells from leaves to reveal density-dependent population growth, and treatment 2 inoculated leaves with an Ap strain engineered to express green fluorescent protein (GFP), which made it possible to track the fate of immigrant cells. The experiments showed that natural populations of Ap vary greatly in density due to sustained differences in carrying capacities among leaves. The maintenance of populations close to carrying capacities indicates strong density-dependent processes. Furthermore, resident populations are strongly competitive against immigrants, while immigrants have little impact on residents. Finally, statistical models showed high population growth rates of resident cells in one experiment but not in the other, suggesting that Ap experiences relatively "good" and "bad" periods for population growth. This picture of Ap dynamics conforms to commonly held, but rarely demonstrated, expectations of microbe dynamics in nature. It also highlights the importance of local processes, as opposed to immigration, in determining the abundance and dynamics of microbes on surfaces in terrestrial systems.     

Remote Antarctic feeding ground important for east Australian humpback whales

Understanding the dynamics of population recovery is particularly complex when an organism has multiple, remote breeding and feeding grounds separated by one of the longest known migration routes. This study reports on the most comprehensive assessment of humpback whale (Megaptera novaeangliae) movements between remote Antarctic waters south of New Zealand and east Australia (EA), and the migratory corridors and breeding grounds of Australia and Oceania. A total of 112 individual whales were identified; 57 from microsatellites and 61 by fluke with 23 % (n = 26) matched to sites outside Antarctica. Despite large datasets from other southern regions being included in the comparison, the whales were predominantly linked to EA (n = 24). Only two matches to the Oceania catalogues directly north was surprising; therefore the primary feeding grounds of these endangered whales still remain unknown. The confirmation of the Balleny Islands as an important feeding ground for EA whales could provide an insight into reasons behind the rapid recovery of this population. Determining the feeding grounds of Oceania’s whales may explain whether prey energetics or migration length are limiting factors to their recovery and will allow an understanding of future ecosystem changes in these whales.     

Some observations on the interactions of marine protozoa and crude oil residues

Marine protozoa were observed to take up Kuwait crude-oil residues in the laboratory and the field. The results suggest that the ingestion occurs only whilst the organisms are feeding on normal food sources.     

Size-fractionated plutonium isotopes in a coastal environment

We have examined the distribution of individual Pu isotopes (239Pu, 240Pu, and 241Pu) in seawater from the Gulf of Maine (GOM). Samples were size-fractionated with a 1 kD cross-flow ultrafiltration (CFF) membrane. Subfractioned samples were radiochemically purified and Pu isotopes were analyzed using a three-stage thermal ionization mass spectrometer (TIMS). To our knowledge, this is the first time that both size class and Pu isotopic data have been obtained for seawater samples. Within measurement uncertainties a single 240Pu/239Pu atom ratio of 0.18 was found for all sample collection depths and sample size fractions. This signifies a current, single Pu source in GOM waters, namely global fallout, and suggests that no measurable isotopic fractionation occurred during CFF processing. The majority of Pu was found in the low molecular weight fraction (< 1 kD). Colloidal Pu varied from 8% of the total in surface waters to < 1% in the deepest (250 m) seawater sample. Evidence suggests that the vertical distribution of Pu in GOM is primarily controlled by conservative mixing processes. The high Pu fraction found in the low molecular size fraction implies that most of the Pu is in the non-particle-reactive oxidized fraction, and is consistent with the conservative Pu behavior. The activity levels are in agreement with other studies which show a slow decrease in Pu with time due to continued mixing and relatively slow particle removal.     

Teratogenic evaluation of the pesticides baygon, carbofuran, dimethoate and EPN

Baygon was administered IG once daily to CD rats (5 to 50 mg/kg), on the 7th-19th day of gestation or to CD-1 mice (5 to 60 mg/kg) on days 6-16 of gestation. Baygon, at dose levels which were not maternally lethal, did not produce fetotoxicity, fetal lethality or malformations in the fetuses. Baygon was not teratogenic in the CD rat or CD-1 mouse at maternally nontoxic dose levels. Carbofuran was administered IG once daily to CD rats (0.05 to 5.0 mg/kg), on the 7th-19th day of gestation or to CD-1 mice (0.1 to 20 mg/kg) on days 6-16 of gestation. At dose levels which were not maternally lethal, carbofuran did not produce fetotoxicity, fetal lethality or malformations in the fetuses. Carbofuran was not teratogenic in the CD rat or CD-1 mouse at maternally nontoxic dose levels. Dimethoate was administered IG once daily to CD-1 mice (10 to 80 mg/kg), on the 6th-16th day of gestation. At dose levels which were not maternally lethal, dimethoate did not produce fetotoxicity, fetal lethality or malformations in the fetuses. Dimethoate was not teratogenic in the CD-1 mouse at maternally nontoxic dose levels. EPN was administered IG once daily to CD-1 mice (1.0 to 12.0 mg/kg) on the 6th-16th day of gestation. EPN, at dose levels up to those which were maternally lethal, did not produce fetotoxicity, fetal lethality or an increase in malformations. EPN was not teratogenic in the CD-1 mouse at maternally nontoxic dose levels.     

Environmental management systems: Opportunities for improved environmental and business strategy?

Less than four years after publication of ISO 14001, thousands of organizations worldwide have adopted the standard. In this article, researchers working with the National Database on Environmental Management Systems (NDEMS) review some preliminary data on organizations' experiences with EMS adoption and implementation. Their findings indicate that, although organizations may face hurdles in implementing EMSs, the majority believes the benefits outweigh the drawbacks. © 2000 John Wiley & Sons, Inc.     

Microplastics for Use in Environmental Research

Journal of Polymers and the Environment - Microplastics?&lt;?20&nbsp;μm are being increasingly reported in treated drinking water as well as in surface waters. As such,...