Cubes and orientability

AbstractWe define and study a new class of matroids: cubic matroids. Cubic matroids include, as a particular case, all affine cubes over an arbitrary field. There is only one known orientable cubic matroid: the real affine cube. The main results establish as an invariant of orientable cubic matroids the structure of the subset of acyclic orientations with LV-face lattice isomorphic to the face lattice of the real cube or, equivalently, with the same signed circuits of length 4 as the real cube

SEISMO-ELECTROMAGNETIC PHENOMENA IN TECTONICALLY ACTIVE REGIONS

This work presents a research plan that aims to monitor seismo-electromagnetic signals in seismic active regions. Two effects will be considered: electromagnetic field emissions and radio broadcastings. Our study will be focused in the analysis of low magnitude earthquakes almost completely disregarded in literature. We aim to collect novel seismo-electromagnetic emission data emerging from seismic activity. We expect to address the time variation of electromagnetic properties of the crust in relation with the strain field and complement it with the development of proper models. Experimental studies based on the electrical properties of rocks will also be done aiming the understanding of pressure stimulated currents and voltages that produce detectable electromagnetic radiation and can be a cause for seismo-electromagnetic signals

Desempenho Agronômico De Batata Doce Sob Diversos Níveis De K

Sweet potato is a vegetable with great potential due to its versatility of use,which covers human food,animal feed and biofuels. However,it is still little studied,especially regarding mineral nutrition and potassium. Thus,a study was conducted to evaluate potassium fertilizer doses (0,30,60,90,120 and 150 kg/ha K2O) on mineral nutrition and yield of ‘Beauregard’ sweet potato in a typic Hapludult soil with low K level (0.3 mmolc/dm3). The experimental design was of randomized blocks with four repetitions. Harvest took place 123 days after seedling transplanting. Foliar K content,shoot,root and total dry matter,root total yield,root commercial yield,K accumulation,K content in the soil and K optimal economic dose were assessed. The highest foliar K content was observed at the dose of 100 kg/ha K2O,with K value of 44.6 g/kg on leaf dry matter. In soils with low K availability,the highest yield (38 t/ha) was observed at the dose of 87 kg/ha K2O. Maximum commercial yield (24.3 t/ha) was obtained at the dose of 85 kg/ha K2O,and K accumulation of 150 kg/ha in the shoot and 57 kg/ha in the root,respectively,were observed (72.5 and 27.5%). Optimal economic production was of 71 kg/ha K2O,which corresponds to 83% of the dose that maximized commercial production. © 2016,Sociedade de Olericultura do Brasil. All rights reserved.34458859

Fragmented host distribution and trombiculid parasitic load: Eutrombicula araucanensis and Liolaemus pictus in Chile

International audienceHabitat fragmentation produced by human impacts can generate changes in the distribution and abundance of populations across their geographic ranges. The chigger mites are ectoparasites that are widely distributed on a wide range of species. The distribution depends of the characteristics of the host and of the habitat where said species is found. As the host distribution is highly dependent on environmental factors, chigger mites are good study models to test geographical distribution patterns. The main objective of this study was to determine variation in abundance of Eutrombicula araucanensis, parasite on Liolaemus pictus, by testing three hypotheses: abundant centre hypothesis, abundance optimum hypothesis and latitudinal distribution pattern. For this purpose, mites from 147 individuals from 23 localities along the distribution of L. pictus were extracted. The three distribution models evaluated in the present study were not adequate to represent the geographical structure of parasitic mites on L. pictus. No association between the distance from the area of greatest species abundance and relative intensity, or association with the distance to the mite’s distribution centre was observed. In addition, no latitudinal distribution pattern was observed. Temperate forest fragmentation may influence the population density of mites, with each forest patch having different optimal conditions for development. The heterogeneity makes it difficult to find a clear distribution pattern

L-Theanine promotes cultured human Sertoli cells proliferation and modulates glucose metabolism

L-Theanine is the major free amino acid present in tea (Camellia sinensis L.). The effects of several tea constituents on male reproduction have been investigated, but L-theanine has been overlooked. Sertoli cells (SCs) are essential for the physical and nutritional support of germ cells. In this study, we aimed to investigate the ability of L-theanine to modulate important mechanisms of human SCs (hSCs) metabolism, mitochondrial function and oxidative profile, which are essential to prevent or counteract spermatogenesis disruption in several health conditions.info:eu-repo/semantics/publishedVersio

Are biological species and higher-ranking categories real? Fish folk taxonomy on Brazil’s Atlantic Forest coast and in the Amazon

Analysis of Brazilian fishers' classifications of 24 marine (Atlantic coast) and 24 freshwater (Amazon) fish species reveals that fishers from the Atlantic coast identify fish mainly through generic names (primary lexemes), while riverine Amazonian fishers typically identify them through binomials. The similarity of Amazonian fish species seems to contribute to the detailed folk taxonomy used by riverine fishers. High-ranking groups called "relatives" or "cousins" are sorted by fishers in terms of similarities of habitat, diet, and morphology and, secondarily, behavior. The general correspondence between the folk and scientific taxonomies reinforces the reality of both the supracategories used by these fishers and the biological groups as discontinuities in nature. Given the urgency of biological inventories and the lack of knowledge of high-biodiversity environments such as the Atlantic Forest and the Amazon, these results suggest that fisher knowledge and experience could contribute to scientific research.49229130

The Action of Polyphenols in Diabetes Mellitus and Alzheimer's Disease: A Common Agent for Overlapping Pathologies

Diabetes Mellitus (DM) and Alzheimer's disease (AD) are two prevalent diseases in modern societies, which are caused mainly by current lifestyle, aging and genetic alterations. It has already been demonstrated that these two diseases are associated, since individuals suffering from DM are prone to develop AD. Conversely, it is also known that individuals with AD are more susceptible to DM, namely type 2 diabetes (T2DM). Therefore, these two pathologies, although completely different in terms of symptomatology, end up sharing several mechanisms at the molecular level, with the most obvious being the increase of oxidative stress and inflammation. Polyphenols are natural compounds widely spread in fruits and vegetables whose dietary intake has been considered inversely proportional to the incidence of DM and AD. So, it is believed that this group of phytochemicals may have preventive and therapeutic potential, not only by reducing the risk and delaying the development of these pathologies, but also by improving brain's metabolic profile and cognitive function. The aim of this review is to understand the extent to which DM and AD are related pathologies, the degree of similarity and the relationship between them, to detail the molecular mechanisms by which polyphenols may exert a protective effect, such as antioxidant and anti-inflammatory effects, and highlight possible advantages of their use as common preventive and therapeutic alternatives.info:eu-repo/semantics/publishedVersio

Metabolic dynamics of human Sertoli cells are differentially modulated by physiological and pharmacological concentrations of GLP-1

Obesity incidence has pandemic proportions and is expected to increase even further. Glucagon-like peptide-1 (GLP-1) based therapies are well-established pharmacological resources for obesity treatment. GLP-1 regulates energy and glucose homeostasis, which are also crucial for spermatogenesis. Herein, we studied the GLP-1 effects in human Sertoli cells (hSCs) metabolism and mitochondrial function. hSCs were cultured in absence or exposed to increasing doses of GLP-1 mimicking physiological post-prandial (0.01 nM) levels or equivalent to pharmacological levels (1 and 100 nM) used for obesity treatment. We identified GLP-1 receptor in hSCs. Consumption/production of extracellular metabolites were assessed, as well as protein levels or activities of glycolysis-related enzymes and transporters. Mitochondrial membrane potential and oxidative damage were evaluated. Glucose consumption decreased, while lactate production increased in hSCs exposed to 0.01 and 1 nM GLP-1. Though lactate dehydrogenase (LDH) protein decreased after exposure to 100 nM GLP-1 its activity increased in hSCs exposed to the same concentration of GLP-1. Mitochondrial membrane potential decreased in hSCs exposed to 100 nM of GLP-1, while formation of carbonyl groups was decreased in those cells. Those effects were followed by an increase in p-mammalian target of rapamycin (mTOR) Ser(2448). Overall, the lowest concentrations of GLP-1 increased the efficiency of glucose conversion to lactate, while GLP-1 concentration of 100 nM induces mTOR phosphorylation, decreases mitochondrial membrane potential and oxidative damage. GLP-1 regulates testicular energy homeostasis and pharmacological use of GLP-1 analogues could be valuable to counteract the negative impact of obesity in male reproductive function.info:eu-repo/semantics/publishedVersio

Battery-like behavior of Ni-ceria based systems: synthesis, surface defects and electrochemical assessment

NiO, CeO2 and respective composites are extensively used in energy storage devices due to mostly their high electrochemical activity. However, the assessment of battery-like behavior of Ni-ceria based systems comprising (Ni or Gd)-doped ceria combined with NiO seems to be neglected in the literature. In this work, NiO and ceria-based solid solutions composite powders were obtained by a co-precipitation synthesis method. The structure and particle size of the calcined powders were investigated by X-ray diffractometry (XRD) and field emission scanning electron microscopy (FESEM), respectively. Oxidative states of composites were inspected by X-ray photoelectron spectroscopy (XPS). The electrochemical performance of powders was evaluated by cyclic voltammetry, galvanostatic charge-discharge and impedance spectroscopy. Refinement of the XRD patterns showed that powders have nanosized crystallites and mean size of particles within 20 – 70 nm were revealed by FESEM. The improved specific capacity of the NiO-CeO2 electrode material (about 2.5 times higher than that of NiO-CGO at 5 mV s−1) is due to an increase in Faradic reactions taken place on its surface with a higher fraction of defects (namely Ni3+, Ce3+ and oxygen vacancies), as determined by XPS. The superior electrochemical performance of the NiO-CeO2 electrode is also confirmed by electrochemical impedance spectroscopy.publishe