Selecting indicator species to monitor ecological integrity: a review

We review critical issues that must be considered when selectingindicator species for a monitoring program that aims to maintainor restore ecological integrity. First, we examine the pros andcons of different management approaches on which a conservationprogram can be based and conclude that ecosystem management ismost appropriate. We then identify potential indicators ofecological integrity at various levels of the ecosystem, with aparticular emphasis on the species level. We conclude that,although the use of indicator species remains contentious, it canbe useful if (1) many species representing various taxa and lifehistories are included in the monitoring program, (2) theirselection is primarily based on a sound quantitative databasefrom the focal region, and (3) caution is applied wheninterpreting their population trends to distinguish actualsignals from variations that may be unrelated to thedeterioration of ecological integrity. Finally, we present anddiscuss different methods that have been used to select indicatorspecies.     

Hydrodehalogenation of chlorobenzene on activated carbon and activated carbon supported catalysts

Chlorinated aromatic compounds in (waste) gases can be removed and/or dehalogenated by passing over a bed of activated carbon (AC) in a hydrogen containing atmosphere. Dehalogenation of the model compound chlorobenzene (PhCl) to HCl is complete at 490 degrees C--rather than the approximately 900 degrees C needed for the mere gas-phase reaction--but part of the benzene moieties is retained on the AC, resulting in its rather rapid deactivation, apparently due to a large decrease in surface area. Therefore, <1 mmol PhCl per gram of 'catalyst' could be processed. At 600 degrees C chlorobenzene yields 100% of both HCl and benzene, but still the AC lost most of its activity in time. Performances are compared of three different commercial ACs. As a HCl-washed AC is just as active, metals are not involved. This acid-washed AC was used as a support for 10 wt% Ni or Fe catalysts. While Fe did not show appreciable activity, results with Ni are promising. The yields of HCl and benzene from PhCl are approximately 100% already at T<400 degrees C, and T(50%) congruent with 260 degrees C, over 200 degrees C lower than with AC alone. There is no appreciable decrease of activity after having injected >20 mmol PhCl per gram of catalyst at partial conversion.     

INTERNATIONAL OIL: THE RISKS OF A FRAGMENTED SYSTEM

This article examines the premise that the risks presented by the disintegration of petroleum operations threaten the balance between supply and demand. However effective the former international system has been in this area, today's fragmentation is a fact that is justified by the desire on the part of national corporations of many countries to control their petroleum production. But it is still important to avoid waste and to work towards rational exploitation of hydrocarbons at the regional level, if not on a global scale. Recognition of this problem on the international level will facilitate its solu ion. The UN and its specialized agencies can play an important role in this regard. It is also necessary to appeal to the petroleum companies whose experience may be valuable to national enterprises in the field of industrial co-operation. Dans cet article, l'auteur part d'un constat: les risques que présente pour une adaptation adéquate de l'offre et de la demande, la désintégration des opérations pétrolières. Quel que positif qu'ait été à cet égard l'ancien système international de l'industrie pétrolière, cette fragmentation actuelle est un fait: il trouve d'ailleurs sa justification principale dans les aspirations nationales des pays qui ont voulu prendre le contrôle des activités pétrolières. Mais il importe toujours d'éviter le gaspillage et de tendre vers une exploitation rationnelle des hydrocarbures à l'échelon régional, sinon mondial. La prise de conscience de ce problème au niveau international doit permettre de tendre vers cet objectif. L'ONU et ses institutions spécialisées peuvent jouer ici un rôle important. Il faut aussi faire appel aux Compagnies pétrolières dont l'expérience peut être utile pour les Compagnies nationales dans le cadre d'une coopération industrielle. Este artículo examina la premisa de que los riesgos que presenta la desintegración del sistema de operaciones petroleras amenaza el balance entre demanda y oferta. No importa cuan efectiva haya sido el sistema internacional anterior, la fragmentación presente es un hecho que se justifica por el deseo de controlar la producción de petróleo por parte de las corporaciones nacionales. Pero aún es importante evitar el desperdicio y procurar la explotación racional a nivel regional o si es posible a escala mundial. El reconocimiento de este problema a nivel internacional facilitará su solución. La ONU y sus agencias especializadas pueden jugar un rol importante a este respecto. Estambién necessario hacer un llamado a las compañías petroleras cuya experiencia puede ser valiosa a las empresas nacionales en el campo de co-operación industrial.     

Differential thermal performance curves in response to different habitats in the parasitoid <Emphasis Type="Italic">Venturia canescens</Emphasis>

Environmental variability is expected to be important in shaping performance curves, reaction norms of phenotypic traits related to fitness. Models predict that the breadth of performance curves should increase with environmental variability at the expense of maximal performance. In this study, we compared the thermal performance curves of two sympatric populations of the parasitoid Venturia canescens that were observed under contrasting thermal regimes in their respective preferred habitats and differing in their modes of reproduction. Our results confirm the large effect of developmental temperature on phenotypic traits of insects and demonstrate that thelytokous and arrhenotokous wasps respond differently to temperature during development, in agreement with model predictions. For traits related to fecundity, thelytokous parasitoids, which usually occur in stable thermal conditions, exhibit specialist performance curves, maximising their reproductive success under a restricted range of temperature. In contrast, arrhenotokous parasitoids, which occur in variable climates, exhibit generalist performance curves, in keeping with the hypothesis "jack of all temperatures, master of none".     

Knowledge, attitude, and practice of Nigerian commercial motorcyclists in the use of crash helmet and other safety measures

OBJECTIVE: This study was designed to evaluate the knowledge, attitude, and practice of some commercial motorcyclists in Nigeria in the use of crash helmet and other cycling safety measures. METHODS: At randomly selected commercial motorcycle parks from two South Western Nigerian locations (Lagos and Ile-Ife), we obtained verbal consent from commercial motorcyclists (randomly selected) and thereafter administered structured questionnaires to consenting motorcyclists. The questionnaire sought to know the respondents' biodata (age, gender, and educational attainment inclusive), cycling background, and experience (trainer, duration of training and cycling, and history of crashes). Furthermore, risk factors and practices like alcoholism, maintenance history of the motorcycle, maximum number of pillion passengers carried, and use of crash helmet were elicited. Respondents' knowledge of available safety measures was also investigated. Data was entered into an IBM compatible computer and analyzed using the SPSS 11.0 statistical software. Statistical significance was inferred at p value<0.05. RESULTS: There were 224 male respondents aged 15-58 years. Their peak age was 25-29 years and mean 35.1+/-8.9 years; 8.4% had no formal education; 10.3% received formal training but the majority were either trained by self (35.5%) or an acquaintance (34.6%). Training lasted相似文献   

A review on molecular topology: applying graph theory to drug discovery and design

Molecular topology is an application of graph theory and statistics in fields like chemistry, biology, and pharmacology, in which the molecular structure matters. Its scope is the topological characterization of molecules by means of numerical invariants, called topological indices, which are the main ingredients of the molecular topological models. These are statistical models that are instrumental in the discovery of new applications of naturally occurring molecules, as well as in the design of synthetic molecules with specific chemical, biological, or pharmacological properties. In this review, we focus on pharmacology, which is a novel field of application of molecular topology. Besides summarizing some recent developments, we also seek to bring closer this interesting biomedical application of mathematics to an interdisciplinary readership.

Mapping knowledge investments in the aftermath of Hurricane Katrina: a new approach for assessing regulatory agency responses to environmental disaster

In the aftermath of large-scale disasters, the public's dependency on federal and state agencies for information about public safety and environmental risk is acute. While formal rules and procedures are in place to guide policy decisions in environmental risk assessment of spatially concentrated hazards such as regulated waste sites or vacant city lots, standard procedures for risk assessment seem potentially less well-suited for urban-scale disaster zones where environmental hazards may be widely dispersed and widely varying. In this paper we offer a new approach for the social assessment of regulatory science in response to large-scale disaster, illustrating our methodology through a socio-spatial analysis of the U.S. Environmental Protection Agency's (EPA) hazard assessment in New Orleans, Louisiana, following Hurricane Katrina in 2005. We find that the agency's commitment of epistemic resources or “knowledge investments” varied considerably across the flood-impacted portion of the city, concentrating in poorer and disproportionately African American neighborhoods previously known to be heavily contaminated. We address some of the study's social and policy implications, noting the multidimensionality and interactive nature of knowledge investments and the prospects for deepening and extending this approach through comparative research.     

Persistence and growth of faecal culturable bacterial indicators in water column and sediments of Vidy Bay, Lake Geneva, Switzerland

The aims of this study was to investigate the persistence and the growth of culturable bacterial indicators (CBI) including total coliforms (TC) and faecal coliforms represented by Escherichia coli, enterococcus (ENT), and aerobic mesophilic bacteria (AMB) in the surface sediments and the water column of Vidy Bay (Lake Geneva, City of Lausanne, Switzerland). The study was carried out for 60 d using microcosms containing Sewage Treatment Plant (STP) e uent and nonsterile water without CBI, as well as contaminated and non-contaminated sediments. The e ects of water temperature and of organic matter associated with sediments on the survival of CBI in the sediments and the water column were observed. The number of CBI colonies in the contaminated sediments of Vidy Bay and in the STP e uent was almost identical in the order of 105–107, 104–106, 103–105, and 104–107 CFU/100 g sediment or /100 mL water for TC, E. coli, ENT, and AMB respectively. A degradation of CBI was observed in the sediments where organic mater content was low and in the water column at a temperature of 10°C after 5 d of experimentation. In addition, a growth of CBI was observed in the sediment which is rich in organic matter at 20°C. The results of this study indicate: (1) the higher concentrations of the CBI observed in di erent points in the water column of Vidy Bay may not be explained only by the recent contribution of the three potential sources of the Bay contamination including STP and the Chamberonne and Flon Rivers, but also by the persistence, removal from sediment and multiplication of CBI in the sediment and water column; (2) the sediment of Vidy Bay constitute a reservoir of CBI and can even support their growth; and (3) the CBI not only survive in sediments, but also can be remobilized and increased in the water column, therefore, it become a permanent microbiological pollution in Vidy Bay.     

Food web analysis in intertidal <Emphasis Type="Italic">Zostera marina</Emphasis> and <Emphasis Type="Italic">Zostera noltii</Emphasis> communities in winter and summer

The food web of two intertidal seagrass (Zostera marina and Zostera noltii) beds that may be influenced by the seasonal variation in food source abundance was studied in winter and in summer with δ¹³C and δ¹⁵N analysis. In spite of high relative variation of abundance of main primary producers at the two sites, the food web did not vary between winter and summer. The δ¹³C range of primary producers was wide. Zostera leaves, the most ¹³C-enriched source, were not consumed directly by grazers. Deposit and filter feeders have a similar δ¹³C and could use a mix of suspended and sedimented organic particulate matter, largely composed of detritus from macroalgae to seagrass. This trophic pathway allows the local incorporation of the high biomass produced by seagrasses. The wide δ¹⁵N range of predators was linked either to a large variety from omnivore to carnivore predators or to the also wide ranges of δ¹⁵N of primary consumers.     

Microstructures of Antarctic cidaroid spines: diversity of shapes and ectosymbiont attachments

The echinoderm endoskeleton, located in the connective layer of the tegument, is organized into a three-dimensional mesh, the stereom. Among echinoids, the cidaroids depart from this pattern, and the shaft of the spine lacks an epidermis. Thus, the spines lack antifouling protection, allowing ectosymbionts such as bryozoans and foraminiferans to attach. This raises a question about the adaptive role of the cortical layer of the stereom. This study examined the micro- and mesostructure of the spines of 11 cidaroid species collected in the Weddell Sea and Drake Passage, and the nature of their ectosymbiont attachments. Scanning electron microscopy was used to characterize the cortex surface and X-ray micro computed tomography (μCT) to describe the symbiont attachments. Spine microstructure features provide a useful taxonomic character for distinguishing among three species in the genus Ctenocidaris, and challenge a previous parasitic interpretation of cortical filaments on the spines of Rhynchocidaris triplopora. Ectosymbiont attachments were classified as Anchoring, Molding, Cementing, or Corroding. The study suggests that some microstructure features may be protective, keeping the ectosymbionts away from the cortex and loosely attached at intervals along the shaft of the spine, while other micro-structures facilitate attachment over considerable areas of the shaft. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.