Genetic Variation and Outcrossing Rate in Relation to Population Size in Gentiana pneumonanthe L

The amount of genetic variation in the rare perennial herb Gentiana pneumonanthe L. was determined to explore its relation to population size. Differences in isozyme variation between maternal plants and their offspring were used to investigate the relationship between population size and outcrossing rate. In 25 populations in The Netherlands, differing in size from 1 to more than 50,000 flowering individuals, 16 allozyme loci were analyzed on leaves of maternal plants and offspring grown in a greenhouse. Population size was significantly positively correlated with the proportion of polymorphic loci, but only marginally with heterozygosity and the mean effective number of alleles. Most of the studied populations were characterized by a complete absence of rare alleles, and F -statistics suggest relatively high levels of genetic differentiation among populations and thus a low level of gene flow. Leaf samples (maternal) were mostly in Hardy-Weinberg equilibrium, while several offspring samples showed an excess of homozygotes, which suggests selection favoring heterozygotes. Because most small populations consist only of adult survivors from formerly larger populations, this may partly explain the absence of a clear relationship between genetic variation of the maternal plants and population size. A significant positive correlation was found between the level of cross-fertilization and population size. From these results, we conclude that, to some degree, small populations have a reduced level of genetic variation, while their present isolation in nature reserves has resulted in a very limited interpopulational gene flow level. At present a higher level of inbreeding in small populations contributes to a further loss of genetic variation and may also result in reduced offspring fitness.     

内在安全的生产,对清洁生产的一种正常的补充

内在的安全性,是一种利用没有毒性、可燃性或不稳定性的工艺与材料的方法,它通常被认为是化工厂设计的一个重要概念.受到清洁生产成功发展的鼓舞,进行了一项类似的有关内在安全生产的发展可行性研究.在1997-1998年进行的初步试验案例中,发展并检验了一个产生内在安全的技术选择的方法论.该研究表明,大部分选择的偿还时间少于两年,而且内在安全的生产是一个可行的概念,有可能同时产生巨大的安全与经济成效的改善,并且可以结合进清洁生产计划.     

Environmental bonds and the challenge of long-term carbon sequestration

The potential to capture carbon from industrial sources and dispose of it for the long-term, known as carbon capture and sequestration (CCS), is widely recognized as an important option to reduce atmospheric carbon dioxide emissions. Specifically, CCS has the potential to provide emissions cuts sufficient to stabilize greenhouse gas levels, while still allowing for the continued use of fossil fuels. In addition, CCS is both technologically-feasible and commercially viable compared with alternatives with the same emissions profile. Although the concept appears to be solid from a technical perspective, initial public perceptions of the technology are uncertain. Moreover, little attention has been paid to developing an understanding of the social and political institutional infrastructure necessary to implement CCS projects. In this paper we explore a particularly dicey issue--how to ensure adequate long-term monitoring and maintenance of the carbon sequestration sites. Bonding mechanisms have been suggested as a potential mechanism to reduce these problems (where bonding refers to financial instruments used to ensure regulatory or contractual commitments). Such mechanisms have been successfully applied in a number of settings (e.g., to ensure court appearances, completion of construction projects, and payment of taxes). The paper examines the use of bonding to address environmental problems and looks at its possible application to nascent CCS projects. We also present evidence on the use of bonding for other projects involving deep underground injection of materials for the purpose of long-term storage or disposal.     

Personal Exposure to Fine Particulate Matter in Elderly Subjects: Relation between Personal,Indoor, and Outdoor Concentrations

ABSTRACT

The time-series correlation between ambient levels, indoor levels, and personal exposure to PM_2.5 was assessed in panels of elderly subjects with cardiovascular disease in Amsterdam, the Netherlands, and Helsinki, Finland. Subjects were followed for 6 months with biweekly clinical visits. Each subject's indoor and personal exposure to PM_2.5 was measured biweekly, during the 24-hr period preceding the clinical visits. Outdoor PM_2.5 concentrations were measured at fixed sites. The absorption coefficients of all PM_2.5 filters were measured as a marker for elemental carbon (EC). Regression analyses were conducted for each subject separately, and the distribution of the individual regression and correlation coefficients was investigated. Personal, indoor, and ambient concentrations were highly correlated within subjects over time. Median Pearson's R between personal and outdoor PM_2.5 was 0.79 in Amsterdam and 0.76 in Helsinki. For absorption, these values were 0.93 and 0.81 for Amsterdam and Helsinki, respectively. The findings of this study provide further support for using fixed-site measurements as a measure of exposure to PM_2.5 in epidemiological time-series studies.     

High Volume Sampling:Evaluation of an Inverted Sampler for Ambient TSP Measurements

Recent advances in the development of receptor-oriented source apportionment techniques (models) have provided a new approach to evaluating the performance of particulate dispersion models. Rather than limiting performance evaluations to comparisons of particulate mass, receptor model estimates of source impacts can be used to open new opportunities for in-depth analysis of dispersion model performance. Recent experiences in the joint application of receptor and dispersion models have proven valuable in developing increased confidence in source impact projections used for control strategy development. Airshed studies that have followed this approach have identified major errors in emission inventory data bases and provided technical support for modeling assumptions.

This paper focuses on the joint application of dispersion and receptor models to particulate source impact analysis and dispersion model performance and evaluation. The limitations and advantages of each form of modeling are reviewed and case studies are examined. The paper is offered to provide several new perspectives into the model evaluation process in the hope that they may prove useful to those that manage our nation’s air resources.     

A community-based approach to low-income residential energy efficiency participation barriers

Financial barriers are often cited as the principle impediment to the adoption of energy efficiency measures. Since 1976, the US Department of Energy's Weatherisation Assistance Programme (WAP) has provided state block grants for no-cost, low-income energy efficiency retrofits. Yet, millions of low-income American households lack affordable, reliable, and efficient energy access. The American Recovery and Reinvestment Act of 2009 boosted WAP's annual appropriation from $230 million to $5 billion, requiring states to explore innovate approaches to quickly increasing programme participation. Community-based energy programmes have shown success for overcoming various barriers and increasing participation in the adoption of energy technologies. This case study explores a community-based approach to scaling WAP-funded energy efficiency retrofits in a cluster of five urban, low-income, majority African-American neighbourhoods, known as the Green Impact Zone (GIZ), in Kansas City, Missouri. Findings from interviews with GIZ stakeholders suggest that local context is important to how energy efficiency participation barriers manifest. The targeted, community-based approach to WAP created institutional capabilities for increased recognition of participation challenges and facilitated opportunities for alternative solutions that may otherwise have been overlooked under the standard self-referral implementation of WAP. Lastly, effective implementation of WAP required policy workarounds that recognised the unique characteristics and needs of the target community.     

Caribbean mangroves and seagrass beds as daytime feeding habitats for juvenile French grunts, Haemulon flavolineatum

Caribbean seagrass beds are important feeding habitats for so-called nocturnally active zoobenthivorous fish, but the extent to which these fishes use mangroves and seagrass beds as feeding habitats during daytime remains unclear. We hypothesised three feeding strategies: (1) fishes feed opportunistically in mangroves or seagrass beds throughout the day and feed predominantly in seagrass beds during night-time; (2) fishes start feeding in mangroves or seagrass beds during daytime just prior to nocturnal feeding in seagrass beds; (3) after nocturnal feeding in seagrass beds, fishes complete feeding in mangroves or seagrass beds during the morning. We studied the effect of habitat type, fish size, social mode and time of day on resting and feeding behaviour of large juvenile (5–10 cm) and sub-adult (10–15 cm) Haemulon flavolineatum in mangroves and seagrass beds during daytime. Sub-adults occurred in mangroves only, spent most time on resting, and showed rare opportunistic feeding events (concordant with strategy 1), regardless of their social mode (solitary or schooling). In contrast, large juveniles were present in both habitat types and solitary fishes mainly foraged, while schooling fishes mainly rested. Exceptions were small juveniles (±5 cm) in seagrass beds which foraged intensively while schooling. Large juveniles showed more feeding activity in seagrass beds than in mangroves. In both habitat types, they showed benthic feeding, whereas pelagic feeding was observed almost exclusively in the seagrass beds. In both habitat types, their feeding activity was highest during 8:00–10:30 hours (concordant with strategy 3), and for seagrass fishes, it was also high during 17:30–18:30 hours (concordant with strategy 2). The study shows that both mangroves and seagrass beds provide daytime feeding habitats for some life-stages of H. flavolineatum, which is generally considered a nocturnal feeder.     

Quantification of activated carbon contents in soils and sediments using chemothermal and wet oxidation methods

Activated carbon (AC) strongly sorbs organic pollutants and can be used for remediation of soils and sediments. A method for AC quantification is essential to monitor AC (re)distribution. Since AC is black carbon (BC), two methods for BC quantification were tested for AC mixed in different soils and sediments: i) chemothermal oxidation (CTO) at a range of temperatures and ii) wet-chemical oxidation with a potassium dichromate/sulfuric acid solution. For three soils, the amount of AC was accurately determined by CTO at 375 °C. For two sediments, however, much of the AC disappeared during combustion at 375 °C, which could probably be explained by catalytic effects by sediment constituents. CTO at lower temperatures (325-350 °C) was a feasible alternative for one of the sediments. Wet oxidation effectively functioned for AC quantification in sediments, with almost complete AC recovery (81-92%) and low remaining amounts of native organic carbon (5-16%).     

Ecotypic differentiation in the kelpLaminaria saccharina: Phase-specific adaptation in a complex life cycle

Comparison of cultured sporophytes and gametophytes in common-garden experiments confirmed the existence of ecotypic differences in light-related traits among populations ofLaminaria saccharina (L.) Lamour. Cultured sporophytes from the turbid habitat in Long Island Sound, New York, USA, grew faster under both limiting and saturating daily irradiances than sporophytes from shallow and deep habitats along the Atlantic coast of Maine. Rapid growth of turbid plants was attributable to several factors, including high photosynthetic capacity and efficiency [due to differences in photosynthetic unit (PSU) number and size], low respiration rates, and high surface area:weight ratios. In contrast to sporophytes, microscopic gametophytes from the three kelp populations grew at similar rates under limiting and saturating daily irradiances. Biomass-specific photosynthesis vs irradiance (PI) parameters were similar for gametophytes from the shallow, deep, and turbid sites, despite population differences in chlorophyll-specific PI parameters and PSU characteristics. However, turbid gametophytes produced microscopic sporophytes more rapidly than gametophytes from the shallow and deep sites, apparently due to a lower blue-light requirement for gametogenesis. Ecotypic differences in sporophytes and gametophytes ofL. saccharina from shallow, deep, and turbid habitats can be understood as phase-specific adaptations.