Induction of the P450 reporter gene system bioassay by polycyclic aromatic hydrocarbons in Ulsan Bay (South Korea) sediments

Polycyclic aromatic hydrocarbons (PAHs) and induction of the P450 reporter gene system (RGS) for 6- and 16-h exposure periods were determined in organic extracts of Ulsan Bay (South Korea) sediments to assess the utility of this bioassay as a screening tool for PAH contamination. The sum of the concentrations of 23 individual PAHs in 30 sediment samples (sigma PAH) based on GC-MS analysis ranged from 0.05 to 6.1 micrograms/g dry wt. P450 RGS fold induction ranged from 4.0 to 320 micrograms/g based on benzo[a]pyrene toxic equivalents (BaPEq). P450 RGS BaPEq and the 'chemical BaPEq', defined as the sum of the products of individual PAH concentrations and pre-determined toxic equivalency factors, exhibited very strong positive correlations with sigma PAH (r2 > 0.90; P < 0.001). Fold induction did not increase (and in some cases decreased) after the optimal incubation period (6 h) for PAHs, indicating that other compounds known to induce the P450 RGS (e.g. chlorinated organics) were not present at levels effecting significant induction. This was supported by GC-ECD analysis where non-ortho and mono-ortho polychlorinated biphenyls (PCBs) known to be strong P450 RGS inducers were found to be at very low or non-detectable levels in samples with the highest P450 RGS responses. The profound difference in PAH profiles for the two most contaminated sites suggested that this assay is especially sensitive for selected PAHs with greater than four rings. Combined with previous results, the P450 RGS shows promise as a useful screening tool for predicting deleterious biological effects resulting from CYP1A1-inducing, sediment-associated chemicals, particularly high molecular weight PAHs.     

Protected‐Area Boundaries as Filters of Plant Invasions

Abstract: Human land uses surrounding protected areas provide propagules for colonization of these areas by non‐native species, and corridors between protected‐area networks and drainage systems of rivers provide pathways for long‐distance dispersal of non‐native species. Nevertheless, the influence of protected‐area boundaries on colonization of protected areas by invasive non‐native species is unknown. We drew on a spatially explicit data set of more than 27,000 non‐native plant presence records for South Africa's Kruger National Park to examine the role of boundaries in preventing colonization of protected areas by non‐native species. The number of records of non‐native invasive plants declined rapidly beyond 1500 m inside the park; thus, we believe that the park boundary limited the spread of non‐native plants. The number of non‐native invasive plants inside the park was a function of the amount of water runoff, density of major roads, and the presence of natural vegetation outside the park. Of the types of human‐induced disturbance, only the density of major roads outside the protected area significantly increased the number of non‐native plant records. Our findings suggest that the probability of incursion of invasive plants into protected areas can be quantified reliably.     

A Small‐Scale Land‐Sparing Approach to Conserving Biological Diversity in Tropical Agricultural Landscapes

Two contrasting strategies have been proposed for conserving biological diversity while meeting the increasing demand for agricultural products: land sparing and land sharing production systems. Land sparing involves increasing yield to reduce the amount of land needed for agriculture, whereas land‐sharing agricultural practices incorporate elements of native ecosystems into the production system itself. Although the conservation value of these systems has been extensively debated, empirical studies are lacking. We compared bird communities in shade coffee, a widely practiced land‐sharing system in which shade trees are maintained within the coffee plantation, with bird communities in a novel, small‐scale, land‐sparing coffee‐production system (integrated open canopy or IOC coffee) in which farmers obtain higher yields under little or no shade while conserving an area of forest equal to the area under cultivation. Species richness and diversity of forest‐dependent birds were higher in the IOC coffee farms than in the shade coffee farms, and community composition was more similar between IOC coffee and primary forest than between shade coffee and primary forest. Our study represents the first empirical comparison of well‐defined land sparing and land sharing production systems. Because IOC coffee farms can be established by allowing forest to regenerate on degraded land, widespread adoption of this system could lead to substantial increases in forest cover and carbon sequestration without compromising agricultural yield or threatening the livelihoods of traditional small farmers. However, we studied small farms (<5 ha); thus, our results may not generalize to large‐scale land‐sharing systems. Furthermore, rather than concluding that land sparing is generally superior to land sharing, we suggest that the optimal approach depends on the crop, local climate, and existing land‐use patterns. Un Método para Reservar Tierras a Pequeña Escala para Conservar la Biodiversidad en Paisajes Agrícolas Tropicales     

Endogenous circatidal rhythm in the Manila clam Ruditapes philippinarum (Bivalvia: Veneridae)

Manila clams, Ruditapes philippinarum, removed from their natural environment and maintained for 9 weeks in continuously immersed conditions exhibited a clear endogenous circatidal rhythm in oxygen consumption. The clams exhibited a semidiurnal rhythmicity in oxygen consumption after showing a diurnal pattern in the first few days (5 to 7 d) of the experiment. The results of the present study indicate that activity rhythms of clams are controlled not only by exogenous factors, but also by an endogenous circatidal periodicity. Received: 8 April 1998 / Accepted: 1 February 1999     

LEGAL ASPECTS OF MINING DEVELOPMENT IN DEVELOPING COUNTRIES

This article discusses the legal criteria of a mining investment decision - the legal status of investments, fiscal regime and mining legislation. The importance of the security of tenure of mining titles and of the stability of the terms and conditions, as stated from the inception, is emphasized, and the concepts of state sovereignty, state ownership of mineral deposits and state participation in mining ventures are considered. The preference for legalistic solutions rather than ad hoc contracts is stated, and a brief review of the various types of mining agreements is given. Cet article analyse les critères juridiques de la decision concernant l'investissement minier: statut juridique des investissements, régime fiscal et legislation minière. L'importance de la sécurité de la concession minière et la garantie des clauses de contrats est mise en evidence. L'article considère également les concepts de souveraíneté de l'Etat, la propriété étatique des dépôts minéraux et la participation de l'Etat dans la recherche minérale. L'auteur indique sa préférence pour des solutions juridiques plutôt que des contrats particuliers et passe brièvement en revue les différents types d'accords miniers. Este artículo analiza los criterios legates empleados en la toma de decisiones sobre inversión minera: estado legal de la inversión, régimen fiscal y legislación minera. Se da énfasis a la importancia de la seguridad de posesión de los títulos mineros, la estabilidad de las condiciones iniciales de contrato y se consideran también los conceptos de soveranía del estado, propiedad estatal de los depósitos mineros y la participación del estado en la actividad minera. Se indica la preferencia por las soluciones a través de leyes en vez de contratos ad hoc y se revisan brevemente varios tipos de acuerdos mineros.     

The effects of transformational leadership on teacher attitudes and student performance in Singapore

Transformational leadership theory was examined in 89 schools in Singapore using a split sample technique (N = 846 teachers). The study sought to examine the influence of transformational leader behavior by school principals as it related to organizational commitment, organizational citizenship behavior, teacher satisfaction with leader, and student academic performance. Attitudinal and behavioral data were collected from both teachers and principals; student academic performance was collected from school records. School level analyses showed that transformational leadership had significant add-on effects to transactional leadership in the prediction of organizational commitment, organizational citizenship behavior, and teacher satisfaction. Moreover, transformational leadership was found to have indirect effects on student academic achievement. Finally, it was found that transactional leadership had little add-on effect on transformational leadership in predicting outcomes. Implications and directions for future research are discussed.     

Diurnal models of traffic-generated CO for Penang,Malaysia

Georgetown of Penang, an old city, is noted for its narrow streets. The existing traffic dispersal system is utterly inadequate to cope with the ever increasing number of cars and motorcycles on the road. The principal objective of this study is to build prediction models of CO to be employed as one of the planning tools in the future design of Penang urban traffic dispersal system. This study involves the monitoring of kerbside CO levels at selected sites and the fitting of hourly-averaged CO data to linear regression models incorporating the residual effect of CO emission due to traffic in the earlier periods and also different categories of vehicles. The best overall regression model appears to be the one based upon the total traffic count of motorcycles. This can be accounted for by the fact that the traffic counts of motorcycles and cars are highly correlated in most cases and that the emissions of CO from motorcycles are more readily detected as they travel closer to the kerb. The inclusion of residual CO in the models significantly improves the correlation coefficient from about 0.4 to about 0.7.     

Assessing anthropogenic impact on Mediterranean sand dunes from aerial digital photography

The Mediterranean region plays host to ca. 33% of the world’s tourism industry. This population of visitors (ca. 147 million in 1990) inevitably exerts an enormous impact on the natural resources of this coastal zone. In May 1997, a new generation Aerial Digital Photographic System [ADPS] configured with a Kodak Digital Science 460 CIR digital camera was used to acquire colour infrared digital photographs of the sand dune systems along the Mediterranean coast of France, from Le Barcares to St-Cyprien-Plage. These have been used to assess the condition of the dunes along this coast. A series of simple analytical techniques to identify and measure features indicative of public pressure using image processing software has been devised. The dune manager with basic computer skills can analyse such indicators as path length, vegetation cover (and conversely the extent of bare sand) to enable monitoring of the performance of their dune systems under particular management regimes. These photographs have been compared with similar digital photographs of dune sites in SW France to allow a comparison of dune degradation in a region with a different population pressure and climate regime. Dune systems sampled from the Mediterranean coastal zone showed more evidence of anthropogenically induced change than those sampled in SW France.     

PM2.5 and volatile organic compounds (VOCs) in ambient air: a focus on the effect of meteorology

PM(2.5) and VOCs (benzene, toluene, m-p-o-xylenes) concentrations were measured in an urban and a suburban site in Athens, Greece, during the period between April and November 2004. This period, which is considered to be the warmer period in Greece, is characterized by the development of sea-breeze over the Attica Basin. Additionally strong Northern, North-eastern winds called "The Etesians", predominate during the summer months (July-August), acting positively to the dispersion of pollutants. In this campaign, 24 days with sea-breeze development were observed, 15 days with northern winds, 6 days with southern winds while the rest of the days presented no specific wind profile. Maximum concentrations of PM(2.5), VOCs and nitrogen oxides, were detected during the days with sea-breeze, while minimum concentrations during the days with northern winds. Ozone was the only pollutant that appeared to have higher concentrations in the background site and not in the city centre, where benzene presented strong negative correlation with ozone, indicating the photochemical reaction of hydrocarbons that lead to the ozone formation. The BTX ratios were similar for both sites and wind profiles, indicating common sources for those pollutants. T/B ratio ranged in low levels, between 3-5 for site A and 2-5 for site B, suggesting vehicles emissions as the main sources of volatile compounds. Finally, the strong correlations of PM(2.5) and benzene concentrations, between the two sampling sites, indicate that both the city centre and the background site, are affected by the same sources, under common meteorological conditions (sea-breeze, northern winds).