Precise sex allocation, local mate competition, and sex ratio shifts in the parasitoid wasp Trichogramma pretiosum

We determined the sex, order, and clutch size of eggs laid by the parasitoid wasp, Trichogramma pretiosum Riley, in the eggs of one of its natural hosts, Trichoplusia ni (Hübner). The parasitoid allocated sex non-randomly to hosts in the laboratory with a variance significantly less than that of a binomial (random) distribution, our null model. More clutches of two or more eggs contained a single male egg as the second or third egg laid than would be expected by chance and none contained two or more male eggs. T. pretiosum also increased the sex ratio (% male) of its offspring with increasing foundress numbers by increasing the frequency of male offspring as the second egg in a two-egg clutch allocated to unparasitized hosts and as the single egg allocated to previously parasitized hosts. These results indicate that T. pretiosum allocates the sex of its offspring precisely. Precise sex allocation is favored under local mate competition because it reduces variation in the number of sons per patch thus maximizing the number of inseminated daughters emigrating from the patch. Similar combinations of female and male offspring emerged from T. ni eggs parasitized by T. pretiosum in the field, again with a sex ratio variance less than that expected for a binomial distribution. These results strongly suggest that this parasitoid species manifests local mate competition.     

UV-irradiation and BDD-based photoelectrolysis for the treatment of halosulfuron-methyl herbicide

Environmental Science and Pollution Research - This paper reports the development of a novel photoelectrochemical (PEC) oxidation technique based on UV-C irradiation and boron-doped diamond (BDD)...     

Occupational risk assessment in construction industry – Overview and reflection

The construction industry is plagued by occupational risky situations and poor working conditions. Occupational risk assessment (ORA) on workplace sites is the first and key step to achieve adequate safety levels, particularly to support decision-making in safety programs. Most construction safety efforts are applied informally under the premise that simply allocating more resources to safety management will improve safety on site. Moreover, there are many traditional methods to address ORA, but few have been adapted and validated for use in the construction industry, particularly in the design stage, for which traditional approaches do not give adequate answers. This paper presents a state-of-the-art on ORA traditional methods, for the construction industry, discussing their limitations and pointing advantages of using fuzzy sets approaches to deal with ill-defined situations.     

Setting population targets for mammals using body mass as a predictor of population persistence

Conservation planning and biodiversity assessments need quantitative targets to optimize planning options and assess the adequacy of current species protection. However, targets aiming at persistence require population‐specific data, which limit their use in favor of fixed and nonspecific targets, likely leading to unequal distribution of conservation efforts among species. We devised a method to derive equitable population targets; that is, quantitative targets of population size that ensure equal probabilities of persistence across a set of species and that can be easily inferred from species‐specific traits. In our method, we used models of population dynamics across a range of life‐history traits related to species’ body mass to estimate minimum viable population targets. We applied our method to a range of body masses of mammals, from 2 g to 3825 kg. The minimum viable population targets decreased asymptotically with increasing body mass and were on the same order of magnitude as minimum viable population estimates from species‐ and context‐specific studies. Our approach provides a compromise between pragmatic, nonspecific population targets and detailed context‐specific estimates of population viability for which only limited data are available. It enables a first estimation of species‐specific population targets based on a readily available trait and thus allows setting equitable targets for population persistence in large‐scale and multispecies conservation assessments and planning.     

Optimisation of bisphenol A removal from water using chemically modified pine bark and almond shell

The ability of pine bark and almond shells to remove bisphenol A (BPA) from aqueous solutions was evaluated. Samples of these traditional agro-forestry by-products were milled, sieved into different particle size fractions (0.10–0.15 and 1.5–2.0 mm) and submitted to two different types of treatment. Sorption experiments were conducted in a batch system at room temperature and natural pH. Sorption equilibrium was attained after 48 h for all systems under study. Bisphenol A was adsorbed more effectively on the smaller particles of the sorbents. Pine bark and almond shell pretreated with formaldehyde presented higher sorption efficiency (95%), followed by almond shell (87%) and pine bark (82%) washed with hot water. All the sorption isotherms were found to fit a Freundlich equation, with correlation coefficients (R ²) between 0.823 and 0.989. The sorption coefficient (K _F) ranged from 0.06 to 0.74 (mg^1?1/n ·L ^1/n ·g ^?1). These results indicate that utilisation of both materials as an alternative sorbent for the removal of bisphenol A from contaminated waters is promising because they are available in large amounts and have an acceptable cost–efficiency ratio when compared with traditional adsorbents.     

Characterization, leachability and valorization through combustion of residual chars from gasification of coals with pine

This paper presents the study of the combustion of char residues produced during co-gasification of coal with pine with the aim of characterizing them for their potential use for energy. These residues are generally rich in carbon with the presence of other elements, with particular concern for heavy metals and pollutant precursors, depending on the original fuel used.The evaluation of environmental toxicity of the char residues was performed through application of different leaching tests (EN12457-2, US EPA-1311 TCLP and EA NEN 7371:2004). The results showed that the residues present quite low toxicity for some of pollutants. However, depending on the fuel used, possible presence of other pollutants may bring environmental risks.The utilization of these char residues for energy was in this study evaluated, by burning them as a first step pre-treatment prior to landfilling. The thermo-gravimetric analysis and ash fusibility studies revealed an adequate thermochemical behavior, without presenting any major operational risks.Fluidized bed combustion was applied to char residues. Above 700 °C, very high carbon conversion ratios were obtained and it seemed that the thermal oxidation of char residues was easier than that of the coals. It was found that the char tendency for releasing SO₂ during its oxidation was lower than for the parent coal, while for NO_X emissions, the trend was observed to increase NO_X formation. However, for both pollutants the same control techniques might be applied during char combustion, as for coal. Furthermore, the leachability of ashes resulting from the combustion of char residues appeared to be lower than those produced from direct coal combustion.     

A Preliminary Index of Biotic Integrity for Monitoring the Condition of the Rio Paraiba do Sul,Southeast Brazil

The biodiversity of many Brazilian rivers is seriously threatened by industrial and municipal pollution, and Rio Paraiba do Sul, located between two major industrial centers is one example of this situation. A survey of the fish assemblage was conducted from October 1998 to September 1999 and the data were used to develop an index of biotic integrity (IBI). We sampled three zones in bracketing a large urban–industrial complex to evaluate water quality changes and the usefulness of the IBI as a monitoring tool. Water quality was classified as poor upstream of the effluent discharges, very poor near the discharges, and poor–fair downstream of the discharges, with this latter situation revealing the current biological capacity of the river. Physical and chemical habitat characteristics were also measured at each site to construct an independent environmental index to validate the IBI. The habitat and IBI indices were highly correlated, suggesting this IBI would be applicable to other large rivers in southeast Brazil.     

Eutrophication and trophic structure in response to the presence of the eelgrass <Emphasis Type="Italic">Zostera noltii</Emphasis>

In estuaries, eelgrass meadows contribute to fundamental ecosystem functions of estuaries, providing food to several predators and buffering the negative effects of eutrophication. We asked whether the presence of the eelgrass Zostera noltii decreased the nitrogen concentration in the overlying water, affected the sources of nitrogen sequestrated by primary producers and changed the benthic and pelagic food web structures. We also studied the importance of these food webs in providing food to fish. We compared bare sediment to sediment covered by a Z. noltii meadow, and examined nutrient concentrations in the water column and δ¹⁵N in primary producers as indicators of anthropogenic inputs of nutrients. We then measured both δ¹³C and δ¹⁵N in the tissues of plants and consumers to establish food web structures. There were no differences in the concentrations and sources of nitrogen between sites. Rather, δ¹⁵N values indicated anthropogenic inputs of N (e.g. sewage discharges, agriculture) in both sites. There were no major differences in the structure of the planktonic food web, which was in part sustained by particulate organic matter and supported most predator fish, and in the structure of the benthic food web. Nonetheless, there were differences in the sources of food for omnivore consumers and for the detritivore Scrobicularia plana. Overall, the benthic food web did not use food derived from the eelgrass or macroalgae deposited on the substratum. Suspension feeders used particulate and sediment organic matter, whereas the δ¹³C and δ¹⁵N values of the other consumers indicated a likely contribution of benthic microalgae. Furthermore, in both habitats we found large variability in the isotope signatures of benthic macrofauna consumers, which did not allow distinguishing clearly different trophic groups and indicated a high level of omnivory and a mixed diet opportunistically making use of the availability of food in the surroundings.