Uncommon formation of two antiparallel sperm bundles per cyst in tenebrionid beetles (Coleoptera)

Several species of Tenebrionidae are stored-grain pests. Since they belong to a specious family, the systematics of these beetles is still in doubt. In insects, spermatogenesis and the spermatozoa exhibit great diversity, and are therefore commonly used in phylogenetic and taxonomic analyses. During the spermatogenetic process in these organisms, the cells originating from a single spermatogonium develop synchronically in groups referred to as cysts. At the end of this process, there is usually only one sperm bundle per cyst, with all the cells in the same orientation. This paper details the spermiogenesis of the tenebrionid beetles Tenebrio molitor, Zophobas confusa, Tribolium castaneum and Palembus dermestoides using whole mount and histological sections of the cysts. In these species, spermatogenesis is similar to that which occurs in most insects. However, during spermiogenesis, the nuclei of the spermatids migrate to two opposite regions at the periphery of the cyst, leading to the uncommon formation of two bundles of spermatozoa per cyst. This feature is possibly an apomorphy for Tenebrionidae.     

What can the Allium cepa test say about pesticide safety? A review

Environmental Science and Pollution Research - The increasing use of pesticides has caused global concerns about the toxic effects and adverse consequences of pesticides on humans and the...     

Remarkable sunlight-driven photocatalytic performance of Ag-doped ZnO nanoparticles prepared by green synthesis for degradation of emerging pollutants in water

Environmental Science and Pollution Research - In this work, Ag-doped ZnO nanoparticles (NPs) were synthesized by a simple green method using a toxic agent-free route for photocatalytic purposes,...     

Encapsulation of Nerol Oil in Polycaprolactone Polymer and Stability Evaluation

Journal of Polymers and the Environment - The objective of this study was to obtain and characterize Nerol essential oil encapsulated in PCL. The miniemulsion and solvent evaporation method was...     

A measure of sustainability of Brazilian agribusiness using directional distance functions and data envelopment analysis

The social and environmental impacts caused by the modernization of Brazilian agribusiness have evoked a growing interest in the search of balance between social-economics development and the adequate use of natural resources, driving the country to sustainable development. Therefore, the main aim of this article is to estimate a set of indicators of relative efficiency in the Brazilian agricultural sector, which satisfy the concept of Pareto optimality, potentiates simultaneously both economic, ecological dimensions and social functions. To reach this purpose, the method of directional distance functions and data envelopment analysis was applied. These indicators confirm, in different ways, the hypothesis that it is possible to perform consistent productive strategies with the maximization of social welfare, despite the apparent antagonism among these three dimensions. In addition, it is shown that efficient Brazilian states tend to combine the three dimensions in different ways. Hence, it can be concluded that several equilibrium taken sustainable can be achieved through different actions on poverty and environmental impact reduction without necessarily generating productive inefficiencies. This result can be considered of prominent importance for sustainable development in Brazil and can also serve as a reference in the definition of goals of the plan ‘Brazil without Misery’ and international commitments to reduce Greenhouse Gas – GHG – in Brazil, especially for the 17 inefficient Brazilian states.     

Internal cohesion and geometric shape of spatial clusters

The geographic delineation of irregularly shaped spatial clusters is an ill defined problem. Whenever the spatial scan statistic is used, some kind of penalty correction needs to be used to avoid clusters’ excessive irregularity and consequent reduction of power of detection. Geometric compactness and non-connectivity regularity functions have been recently proposed as corrections. We present a novel internal cohesion regularity function based on the graph topology to penalize the presence of weak links in candidate clusters. Weak links are defined as relatively unpopulated regions within a cluster, such that their removal disconnects it. By applying this weak link cohesion function, the most geographically meaningful clusters are sifted through the immense set of possible irregularly shaped candidate cluster solutions. A multi-objective genetic algorithm (MGA) has been proposed recently to compute the Pareto-sets of clusters solutions, employing Kulldorff’s spatial scan statistic and the geometric correction as objective functions. We propose novel MGAs to maximize the spatial scan, the cohesion function and the geometric function, or combinations of these functions. Numerical tests show that our proposed MGAs has high power to detect elongated clusters, and present good sensitivity and positive predictive value. The statistical significance of the clusters in the Pareto-set are estimated through Monte Carlo simulations. Our method distinguishes clearly those geographically inadequate clusters which are worse from both geometric and internal cohesion viewpoints. Besides, a certain degree of irregularity of shape is allowed provided that it does not impact internal cohesion. Our method has better power of detection for clusters satisfying those requirements. We propose a more robust definition of spatial cluster using these concepts.     

Influence of support on catalytic behavior of nickel catalysts in the steam reforming of ethanol for hydrogen production

Al₂O₃, MgO, SiO₂ and ZnO-supported nickel catalysts were prepared and evaluated in the ethanol steam reforming for hydrogen production. It is shown that the catalytic behavior can be influenced depending on the experimental conditions employed and chemical composition of the catalyst.     

Preparation of CuO/SiO<Subscript>2</Subscript> and photocatalytic activity by degradation of methylene blue

A photocatalyst based on CuO/SiO₂ was prepared, and evaluated for the degradation of methylene blue in aqueous medium. The photocatalyst was obtained by calcination method of copper salt, in the presence of silica. The characterization by XRD, FTIR, and TPR techniques confirmed the formation of CuO as active phase. SEM studies showed CuO deposited on the surface of SiO₂. By ESI-MS, it was demonstrated that the degradation of methylene blue occurs through successive hydroxylations. Photodegradation assays showed that CuO/SiO₂ was efficient for degradation, and that the material worked better in the presence of UV light.     

Management of sludge from fish ponds at the edge of the Itaparica Reservoir (Brazil): an alternative to improve agricultural production

Sludge generated in intensively managed tilapia fingerling breeding ponds near the Itaparica Dam in the semi-arid Brazilian northeastern region was tested as a soil conditioner to produce lettuce in an effort to mitigate the present environmental impact of the deposition of this sludge, thereby giving it a productive destiny. A greenhouse experiment was performed by mixing the sludge with a Haplic Planosol topsoil, a characteristic soil of the region, so that the sludge corresponded to 0, 25, 50, 75, and 100% of the mixture (substrate). The experiment was set up as a randomized block design with five blocks, each with three pots (5-kg substrate per pot) of the five sludge proportion treatments. One lettuce plant was transplanted into each pot, maintained under greenhouse conditions, and harvested 35 days after transplanting. Sludge, soil, and the substrates were evaluated for nutrient concentration and physical characteristics. Green and dry weights, stem diameter, and nitrogen, phosphorus, and potassium concentrations in the aboveground parts of the lettuce plants were determined. Sludge incorporation into the substrate improved its chemical and physical characteristics. The lettuce plants grew best in the substrate with 75% sludge, increasing its biomass production by 50% and more than doubling its nitrogen uptake.     

Assessment of the hunting of mammals using local ecological knowledge: an example from the Brazilian semiarid region

The hunting of wild animals remains a common activity in various parts of the world, especially in rural communities with poor socioeconomic conditions. To investigate patterns of mammal hunting, this study adopted a rural community located in semiarid Brazil as a model to test whether variables such as perceived abundance, activity period (day or night) and animal biomass could influence the consumption potential of mammal taxa. For this study, a checklist/interview technique using 32 photographs of mammals recorded in the region and two photographs of species that did not occur in the region, which acted as “control” species, was used, in addition to other visual stimuli and free lists. All species presented in the photographs, with the exception of the “control” species, were recognized as occurring in the region. Fourteen species were cited as being those most hunted locally. The species cited as most hunted had an average perceived abundance higher than the group of the least-hunted species. However, there was no significant relationship between hunting of a species and its locally perceived abundance. No significant difference in hunting pressure between diurnal and nocturnal species was found, nor was a relationship between animal biomass and hunting pressure observed. Our findings suggest that perceived abundance is an important factor for choosing a resource fauna, but other factors such as intended use, meat flavor and vulnerability to hunting, among others, may influence the potential use of a species.