Crystal engineering using functionalized adamantane

We performed a first principles investigation on the structural, electronic, and optical properties of crystals made of chemically functionalized adamantane molecules. Several molecular building blocks, formed by boron and nitrogen substitutional functionalizations, were considered to build zincblende and wurtzite crystals, and the resulting structures presented large bulk moduli and cohesive energies, wide and direct bandgaps, and low dielectric constants (low-$\kappa$ materials). Those properties provide stability for such structures up to room temperature, superior to those of typical molecular crystals. This indicates a possible road map for crystal engineering using functionalized diamondoids, with potential applications ranging from space filling between conducting wires in nanodevices to nano-electro-mechanical systems

Structural, Electronic, and Vibrational Properties of Amino-adamantane and Rimantadine Isomers

We performed a first principles total energy investigation on the structural, electronic, and vibrational properties of adamantane molecules, functionalized with amine and ethanamine groups. We computed the vibrational signatures of amantadine and rimantadine isomers with the functional groups bonded to different carbon sites. By comparing our results with recent infrared and Raman spectroscopic data, we discuss the possible presence of different isomers in experimental samples

Functionalized adamantane: fundamental building blocks for nanostructure self-assembly

We report first principles calculations on the electronic and structural properties of chemically functionalized adamantane molecules, either in isolated or crystalline forms. Boron and nitrogen functionalized molecules, aza-, tetra-aza-, bora-, and tetra-bora-adamantane, were found to be very stable in terms of energetics, consistent with available experimental data. Additionally, a hypothetical molecular crystal in a zincblende structure, involving the pair tetra-bora-adamantane and tetra-aza-adamantane, was investigated. This molecular crystal presented a direct and large electronic bandgap and a bulk modulus of 20 GPa. The viability of using those functionalized molecules as fundamental building blocks for nanostructure self-assembly is discussed

On alpha stable distribution of wind driven water surface wave slope

We propose a new formulation of the probability distribution function of wind driven water surface slope with an $\alpha$-stable distribution probability. The mathematical formulation of the probability distribution function is given under an integral formulation. Application to represent the probability of time slope data from laboratory experiments is carried out with satisfactory results. We compare also the $\alpha$-stable model of the water surface slopes with the Gram-Charlier development and the non-Gaussian model of Liu et al\cite{Liu}. Discussions and conclusions are conducted on the basis of the data fit results and the model analysis comparison.Comment: final version of the manuscript: 25 page

The Influence of the Evolutionary Past on the Mind: An Analysis of the Preference for Landscapes in the Human Species

According to some evolutionary psychologists, landscapes preferences in the human species are influenced by their evolutionary past. Because the Pleistocene savanna is the least inhospitable landscape, it was the most suitable environment for survival and influenced the evolution of hominids in such a way that even today the human being has a universal preference for these environments. However, there is controversy regarding this statement, because in some studies it was evidenced that people prefer images of landscapes that are similar to those of the environment where they live. In this sense, we want to test whether there is indeed a preference for images of the savanna landscape and how the current environmental context may influence this preference. We performed a study in three environmental contexts with different landscapes in order to be able to observe the influence of the familiar landscape on landscape preference, of which two rural communities — one presenting a landscape similar to the deciduous seasonal forest and another presenting a savanna-like landscape — that totaled 132 participants and one urban community with 189 participants. The stimulus consisted of 12 images representing the six major terrestrial biomes and two images of urban landscapes. The variables analyzed were the emotional responses and the preference of the participants in relation to the images of landscapes. We analyzed the data using the Kruskal–Wallis test. The obtained result did not corroborate the idea of universal preference for images of savanna landscape. The image of Rainforest landscape was the preferred one among all the three environmental contexts studied. In this way, the preference for landscape may have been shaped at different periods of human evolutionary history, and not just during the period when hominids lived on the savannah. As much as selective pressures of the Pleistocene savanna have shaped the human mind during the evolutionary history, other factors and different types of environments may have influenced human preferences for landscapes. Thus, evolutionary psychologists who analyze human preferences for images of landscapes, guided by the idea of the past influencing the present, must be cautious before generalizing their results, especially if other variables such as the cultural ones are not controlled

Inversion d'un modèle de dispersion avec effets de mémoire

Le MIM (mobile/immobile model) représente la dispersion de contaminant dans de nombreux milieux poreux. Le MIM fractal est une version plus générale avec un opérateur non-local associé à la possibilité pour un traceur, d'être adsorbé pendant des durées très variables. En plus de la diffusivité, ce modèle comporte deux paramètres liés à l'opérateur non-local. Pour inverser des données et caractériser des effets de mémoire, une méthode numérique détermine ces deux paramètres, à partir de profils de concentration en traceur

Evaluation of the brain-derived neurotrophic factor, nerve growth factor and memory in adult rats survivors of the neonatal meningitis by Streptococcus agalactiae

AbstractStreptococcus agalactiae (GBS) is a major cause of severe morbidity and mortality in neonates and young infants, causing sepsis, pneumonia and meningitis. The survivors from this meningitis can suffer serious long-term neurological consequences, such as, seizures, hearing loss, learning and memory impairments. Neurotrophins, such as nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) control the neuronal cell death during the brain development and play an important role in neuronal differentiation, survival and growth of neurons. Neonate Wistar rats, received either 10μL of sterile saline as a placebo or an equivalent volume of GBS suspension at a concentration of 1×106cfu/mL. Sixty days after induction of meningitis, the animals underwent behavioral tests, after were killed and the hippocampus and cortex were retired for analyze of the BDNF and NGF levels. In the open-field demonstrated no difference in motor, exploratory activity and habituation memory between the groups. The step-down inhibitory avoidance, when we evaluated the long-term memory at 24h after training session, we found that the meningitis group had a decrease in aversive memory when compared with the long-term memory test of the sham group. BDNF levels decreased in hippocampus and cortex; however the NGF levels decreased only in hippocampus. These findings suggest that the meningitis model could be a good research tool for the study of the biological mechanisms involved in the behavioral alterations secondary to GBS meningitis