Higher intrinsic photocatalytic efficiency of 2,4,6-triphenylpyrylium-based photocatalysts compared to TiO2 P-25 for the degradation of 2,4-dichlorophenol using solar simulated light

The photocatalytic efficiency of two 2,4,6-triphenylpyrylium (TP(+)) based photocatalysts (supported on silica or incorporated inside zeolite Beta, 3wt%) for the degradation of 2,4-dichlorophenol (DCP) in aqueous media has been compared with TiO(2) (Degussa P-25). It was found that the efficiency of the degradation depends on the photocatalytic setup, recirculation through a tubular reactor being highly unfavorable for the TP(+)-based photocatalysts due to the deposition of the silica or zeolite particles. In contrast, high efficiency in DCP disappearance (up to 87%) and in the total organic content decrease (up to 62%) were obtained using a discontinuous batch reactor in which the TP(+) photocatalysts were uniformly suspended. Kinetic studies were also made and DCP degradation follows a first order kinetics. The obtained kinetic constants when corrected to account for the influence of the fraction of light absorbed and the amount of active sites shows that the intrinsic activity of TP(+) adsorbed on silica or incorporated inside zeolite Beta was over one order of magnitude higher than TiO(2) activity.     

Experimental study on CO2 monitoring and quantification of stored CO2 in saline formations using resistivity measurements

This paper reports CO₂ saturation estimations based on resistivity data obtained from laboratory measurements and induction logging results at the Nagaoka pilot CO₂ injection site. The laboratory experiments put in evidence that the presence of clay content tends to reduce the increase of resistivity caused by the displacement of brine by less conductive CO₂. As a result, CO₂ saturations estimated from resistivity measurements without any correction for the clay effect are considerably lower than the actual saturations. The resistivity index (RI) provides better estimates of CO₂ saturations than the Archie's equation because it requires the determination or assumption of only one rock parameter: the saturation exponent. CO₂ saturations estimated from the induction logging data acquired at Nagaoka are considerably lower than the neutron porosity changes due to displacement between brine and CO₂ in the reservoir. Even in the case of considering the De Witte's equation and the Poupon's to account for the clay effect, it was still difficult to get a good agreement with the neutron logging results. New relations based on the resistivity index with correction factors for the clay effect are developed and implemented in this study. One of these relations has proved to be effective to estimate CO₂ saturations in saline formations with high clay content.     

Shell deformations in the Baltic clam Macoma balthica from southern Baltic Sea (the Gulf of Gdansk): hypotheses on environmental effects

High-resolution digital photography and graphical image analyses systems have been used to define external morphometric characters of shell deformations in four populations of the Baltic clam Macoma balthica from the Gulf of Gdansk (southern Baltic Sea). The proposed shell deformation indices (SDI), which were based on the relationship of selected dimensions in the posterior and the anterior part of the shell, showed at least three morphological features that provide a distinctive diagnosis of "regular" and "deformed" clams: the presence of flexure on the posterior side (SDI1), elongated posterior region (SDI2), and shell growth (SDI3). The degree and prevalence of deformed clams varied locally over space. Increase in percentage contribution of aberrated shells with depth, corresponding to oxygen depletion profile in the Gulf, suggests low oxygen concentrations as the main agent exerting a deforming influence. The observed morphological aberrations developed with age (size) of a bivalve, suggesting a long-term effect of causal factors, and were accompanied by lightening shell weight, possibly due to decalcification of previously deposited calcareous material during anaerobic metabolism. It is hypothesized that hypoxic/anoxic conditions and a subsequent presence of hydrogen sulfide on a deep organic-rich sea bottom induce shell form alterations that enable the pumping of oxygenated water from above the anoxic layer. Such a morphological modification highlights the functional significance of shell deformations in protective response to the ambient low-oxygen concentrations. Sediment organotin concentrations fall within moderate to high contamination range and, therefore, may also have an adverse impact on the shell form. DNA analyses of the fragment of mitochondrial gene cytochrome oxidase I (COI, 393 base pairs) showed homogenous genetic structure of regular and deformed clams, indicating that shell deformations in M. balthica are primarily driven by acclimatization to the ambient environmental conditions.     

Land cover and land use changes in a Brazilian Cerrado landscape: drivers,processes, and patterns

The Cerrado is one of the most threatened biomes in South America. To create protection actions on any scale, understanding drivers and consequences of land cover and land use (LC and LU) is essential. This study defines the composition and configuration of a Cerrado landscape watershed from 1975 to 2011. Using Landsat images and socioeconomic census data, we determined the forces acting on LC and LU change processes and their consequences. LC classes differ from LU classes for landscape dominance and processes. Economic opportunities drove LU change and its spatial distribution was related to soil, streams, and roads. Deforestation was the main cause of forest loss but forest degradation was also important, with both presenting different patterns. The spatial distribution of bare soil was related to pasture in degradation and streams. Bare soil distribution was related to pasture in degradation and streams. We concluded that broad scale factors drove changes, but local features determined distribution, and that watershed conservation plans should act on different scales, with management being spatially explicit.     

The least‐cost biodiversity impact mitigation hierarchy with a focus on marine fisheries and bycatch issues

Least‐cost implementation of the mitigation hierarchy of impacts on biodiversity minimizes the cost of a given level of biodiversity conservation, at project or ecosystem levels, and requires minimizing costs across and within hierarchy steps. Incentive‐based policy instruments that price biodiversity to alter producer and consumer behavior and decision making are generally the most effective way to achieve least‐cost implementation across and within the different hierarchy steps and across all producers and conservation channels. Nonetheless, there are circumstances that favor direct regulation or intrinsic motivation. Conservatory offsets, introduced within the conservatory first three steps of the mitigation hierarchy, rather than the fourth step to compensate the residual, provide an additional incentive‐based policy instrument. The least‐cost mitigation hierarchy framework, induced through incentive‐based policy instruments, including conservatory offsets, mitigates fisheries bycatch consistent with given targets, the Law of the Sea, and the Convention on Biological Diversity.     

Freedom Space for Rivers: A Sustainable Management Approach to Enhance River Resilience

River systems are increasingly under stress and pressure from agriculture and urbanization in riparian zones, resulting in frequent engineering interventions such as bank stabilization or flood protection. This study provides guidelines for a more sustainable approach to river management based on hydrogeomorphology concepts applied to three contrasted rivers in Quebec (Canada). Mobility and flooding spaces are determined for the three rivers, and three levels of “freedom space” are subsequently defined based on the combination of the two spaces. The first level of freedom space includes very frequently flooded and highly mobile zones over the next 50 years, as well as riparian wetlands. It provides the minimum space for both fluvial and ecological functionality of the river system. On average for the three studied sites, this minimum space was approximately 1.7 times the channel width, but this minimum space corresponds to a highly variable width which must be determined from a thorough hydrogeomorphic assessment and cannot be predicted using a representative average. The second level includes space for floods of larger magnitude and provides for meanders to migrate freely over a longer time period. The last level of freedom space represents exceptional flood zones. We propose the freedom space concept to be implemented in current river management legislation because it promotes a sustainable way to manage river systems, and it increases their resilience to climate and land use changes in comparison with traditional river management approaches which are based on frequent and spatially restricted interventions.     

Planktonic ciliates in a hypertrophic pond: functional role and importance

Taxonomical composition and abundance of the planktonic ciliate assemblage in a Lake Tezozomoc, a hypertrophic pond located into an urban park in Mexico City, was investigated along the rainy season (May to October). The aims of the study were to know the main trophic roles and ecological significance of ciliates in a highly productive environment. A low number of taxa (27) and a wide abundance fluctuation (104-387 cil ml(-1)) were found. The most abundant species (up to 162 cil ml(-1)) was Halteria grandinella, an oligotrich ciliate that graze on bacteria and picoplankton, but also several big body sized species that feed on pico and nanoplankton were abundant. Sudden temporal changes in species dominance occurred. Ciliate biomass was very high and fluctuated widely (1.6-88 10(6) microm(3) ml(-1)) being dominated by the >50 microm size fraction that mainly included the pico and nanoplankton feeders. Ciliates are a very important component in the plankton of hypertrophic lakes and their main control factor seems to be the grazing by big-body size Daphnia species.     

Micronucleus study of the quality and mutagenicity of surface water from a semi-arid region

The present study evaluated the mutagenic potential of surface water from the Lucrecia dam. The Tradescantia-micronucleus (Trad-MCN) test and CBMN assay in human peripheral blood lymphocytes were applied, corresponding to an in vivo and in vitro system, respectively. Heavy metals and some physicochemical properties were also measured. Water samples were collected in November 2009 (dry season) and May 2010 (rainy season) at three different points. Results of both assays for raw water showed positive responses for the points analyzed when compared to the negative control. The CBMN assay showed that diluted water was still able to induce a significant increase in micronucleus frequency. For both assays, the highest mean MN was observed in the dry season. Chemical analyses detected an increase in heavy metal levels at the sampling points and in the different seasons. These findings indicate the presence of genotoxins, such as heavy metals, in the water, which may be affecting the entire ecosystem, as well as human health. More prolonged monitoring is recommended in order to better characterize this public water supply.     

Agenesis of the corpus callosum: What to tell expecting parents?

Agenesis of the corpus callosum (ACC) is one of the most common brain malformations, with an incidence estimated to range from 0.5 to 70 in 10,000 among the general population. Prenatal diagnosis is made via ultrasound; however, fetal MRI is useful to confirm or exclude the presence of associated cerebral abnormalities–mostly cortical malformations–that may affect postnatal prognosis. When no additional central nervous system (CNS) or extra CNS anomalies are identified and no genetic cause is found, an isolated ACC is diagnosed. Overall, in cases of ACC, an underlying genetic cause can be identified in up to 12.5% with chromosomal microarray (CMA) and up to 47% with whole exome sequencing (WES). In cases where ACC is the only anomaly detected, the yield of WES is 30%. Postnatal outcomes are variable and depend on whether the condition is isolated or not. In truly isolated ACC, outcomes range from normal in 65% of cases through mild to severe neurodevelopmental impairments in 35% of cases. An interdisciplinary team of medical experts is key in guiding parents toward informed decision-making in pregnancies complicated by ACC. Considering current and expected advancements in genetic testing and imaging technologies in upcoming years, we herein summarize current recommendations for the management and prenatal counseling of expecting parents of fetuses with ACC. Our review pertains primarily to expecting parents of fetuses with complete ACC.     

Lung function among residents from the largest coal region in Brazil

Environmental Science and Pollution Research - Coal mining and burning activities in coal-fired power plants are among the most polluting activities in developing countries. In Brazil, the Candiota...