Analysis of environmental correlates of sexual segregation in northern elephant seals using species distribution models

Elephant seals are among the most sexually dimorphic and polygynous species of all mammals. Their foraging grounds occupy a wide area of the world oceans, where they show spatial segregation between males and females. The objective of this paper was to correlate female and male foraging distributions of Mirounga angustirostris with main climatic variables at a biogeographical scale. We used website and bibliographical sources to obtain information on adult elephant seal distribution and environmental predictors (surface and bottom sea temperatures, productivity and bathymetry) and three species distribution models [maximum entropy model, environmental niche factor analysis and based on climatic envelopes (BIOCLIM)] to predict the habitat suitability of ocean regions. BIOCLIM provided the best fit. Sea surface and bottom temperatures were the variables with the highest explanatory power for females, while bathymetry was for males. Predictive maps suggest that low temperatures constrain female, but not male, distribution at high latitudes. We suggest that large size increases foraging efficiency of males because, among other benefits, it augments thermal insulation, improving the use of cold, rich sectors of the ocean. Different thermoregulatory abilities between sexes due to size dimorphism should be a complementary explanation of sexual segregation in elephant seals.     

Anaerobic whey treatment by a stirred sequencing batch reactor (ASBR): effects of organic loading and supplemented alkalinity

An assessment was made of cheese whey treatment in a mechanically stirred anaerobic sequencing batch reactor (ASBR) containing granular biomass. The effect of increasing organic load and decreasing influent alkalinity supplementation (as sodium bicarbonate) was analyzed. The reactor operated on 8-h cycles with influent COD concentrations of 500, 1000, 2000 and 4000 mg/L, corresponding to volumetric organic loads of 0.6 to 4.8 mgCOD/L.d. Organic COD removal efficiencies were always above 90% for filtered samples. These results were obtained with an optimized alkalinity supplementation of 50% (ratio between mass of NaHCO3 added and mass of influent mgNaHCO3/mgCOD) in the assays with 500 and 1000 mgCOD/L and of 25% in the assays with 2000 and 4000 mgCOD/L. Initial alkalinity supplementation was equal to the mass of influent COD (100%). The system showed formation of viscous polymer-like substances. These were probably of microbiological origin occurring mainly at influent CODs of 2000 and 4000 mg/L and caused some biomass flotation. This could, however be controlled to enable efficient and stable reactor operation.     

Thorough analysis of polyhalogenated compounds in ray liver samples off the coast of Rio de Janeiro, Brazil

Introduction  

Five liver samples of two different ray species (Gymnura altavela and Zapteryx brevirostris) off the coast of Rio de Janeiro, Brazil, were analyzed for their pollution with anthropogenic and naturally occurring organohalogen compounds.     

The problem of disposing of plaster waste from building sites: problem structuring based on value focus thinking methodology

Plaster is a material which is widely used in Brazil on construction sites. However, its use in recent years has been limited by a legal resolution on the environment introduced in Brazil. One of the regions most affected by these restrictions is the Northeast where the strategic importance of plaster for the region is apparent from the extensive economic development, centered on the gypsum pole of Araripe in the state of Pernambuco. This problem has involved many interested parties, among whom are plaster producers, plastering companies, builders, unions (for plaster workers, and construction workers), Town Halls, and so forth. Therefore, there is a need to structure the problem with a view to obtaining a better understanding of the problem given the lack of information on the real decision problem. To reach this objective, value focus thinking (VFT), a methodology that addresses how values can be used to improve the decision making process, was applied and the problem was structured. Thus, it was possible for the parties involved to clarify their objectives, and specify more precisely the consequences and constraints for the decision problem. In addition, each party involved could get a better understanding of their own wishes. In conclusion, the VFT methodology application enables the parties involved to make more consistent decisions, and therefore to ensure that plaster will continue to be used in the construction industry.     

What Drives Accelerated Land Cover Change in Central Argentina? Synergistic Consequences of Climatic,Socioeconomic, and Technological Factors

Synergistic combinations of climatic and land use changes have the potential to produce the most dramatic impacts on land cover. Although this is widely accepted, empirical examples, particularly involving deforestation in Latin America, are still very few. The geographic extent and causes of deforestation in subtropical seasonally dry forests of the world have received very little attention. This is especially true for the Chaco forests in South America, which are being lost at an alarming rate, sometimes higher than those reported for tropical forests. On this basis, the aims of this study were to analyze the changes in land cover that have occurred during the last three decades of the 20th century in the Chaco forests of central Argentina, and to explain the factors that have driven those changes. Results show major land cover changes. Approximately 80% of the area that was originally undisturbed forest is now occupied by crops, pastures, and secondary scrub. The main proximate cause of deforestation has been agricultural expansion, soybean cultivation in particular. This appears as the result of the synergistic convergence of climatic, technological, and socioeconomic factors, supporting the hypothesis of a multiple-factor explanation for forest loss, while providing one of the very few existing analyses of changes in subtropical forests of the world.     

Comparison of the Effect of Plasticizers on PHBV—and Organoclay—Based Biodegradable Polymer Nanocomposites

The aim of this work was to evaluate the effect of different plasticizers on the morphology, crystallization, and mechanical properties of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV)/organomodified montmorillonite (OMt) nanocomposites. We investigated three different plasticizers: dioctyl phthalate (DOP), a commonly used additive in the polymer industry, and two natural and biodegradable plasticizers: epoxidized soybean oil (ESO) and triethyl citrate (TEC). The nanocomposites with 3 wt% OMt were obtained by melt processing in an internal mixer. The plasticizers were used alone or in combination with clay in a concentration of 10 wt%. X-ray diffraction and scanning electron microscopy results revealed a partially intercalated structure. The degree of crystallinity was higher for all of the samples compared to neat PHBV, although the melting temperature decreased with the use of plasticizers combined with OMt. The impact strength results were dependent on the interaction between the components of the system. Triethyl citrate was the most effective plasticizer due to its more pronounced interaction with the PHBV matrix, which yielded improvements in processing conditions and PHBV’s flexibility and impact properties.     

Addition of Saturated Fatty Acids to Biodegradable Films: Effect on the Crystallinity and Viscoelastic Characteristics

Biodegradable films were produced by extrusion from blends of starch, glycerol and poly(butylene adipate co-terephthalate), a biodegradable polyester, with the addition of 1.5 % (wt/wt) saturated fatty acids (caproic, lauric or stearic). Films containing fatty acids had higher crystallinity than control films and the longer the carbon chain of the acid was, the more crystalline the film. Fatty acids with up to 12 carbon atoms did not alter the viscoelastic characteristic of the films. Further, the incorporation of fatty acids did not decrease the hydrophilicity of the films in comparison with the control film without a fatty acid.     

“Return” and Extension Actions After Ethnobotanical Research: The Perceptions and Expectations of a Rural Community in Semi-arid Northeastern Brazil

The scientific community has debated the importance of “return” activities after ethnobiological studies. This issue has provoked debate because it touches on the ethics of research and the relationships with the people involved in these studies. This case study aimed to investigate community perception of an ethnobotany research project that was carried out in the semi-arid region of northeastern Brazil. Furthermore, we reported how the residents of this rural community felt about participating in the activities of “return” that arose from the projects. Our findings demonstrate that “return” activities should be planned from the design phase of the research until its closure as a lifelong process that allows the communities involved to gradually take ownership of the information and actions that are being generated. Similarly, we argue that such activities must be negotiated with the people of the community so that they have decision-making power and autonomy to decide what is most relevant to their lives.     

Evaluation of a low-cost adsorbent for removal of toxic metal ions from wastewater of an electroplating factory

In this study, sugar cane residue or bagasse was used for removal of toxic metal ions from wastewater of an electroplating factory located in northeast Brazil. Prior acid treatment increased the adsorption efficacies in batch wise experiments. The microstructure of the material before and after the treatment was investigated by X-ray diffraction, infrared spectroscopy and scanning electron microscopy. Column operations showed that removals of Cu²⁺, Ni²⁺ and Zn²⁺ from wastewater (in the absence of cyanide) were 95.5%, 96.3.0%, and 97.1%, respectively. Regeneration of the adsorbent obtained in acid indicated that the efficiencies decreased only after the fourth cycle of re-use. Acid-treated sugar cane bagasse can be considered a viable alternative to common methods to remove toxic metal ions from aqueous effluents of electroplating industries.