Periodic Neural Activity Induced by Network Complexity

We study a model for neural activity on the small-world topology of Watts and Strogatz and on the scale-free topology of Barab\'asi and Albert. We find that the topology of the network connections may spontaneously induce periodic neural activity, contrasting with chaotic neural activities exhibited by regular topologies. Periodic activity exists only for relatively small networks and occurs with higher probability when the rewiring probability is larger. The average length of the periods increases with the square root of the network size.Comment: 4 pages, 5 figure

The coffee gene orphanage : S01P14

Coffee is a perennial crop considered one of the most important agricultural commodities in the world. By consequence, aiming at the establishment of tools to help accelerating the genetic improvement of this species, significant advances in coffee genomics have occurred in recent years. As an example, one can cite the recent completion of the complete genome sequencing of Coffea canephora, which will serve as a reference sequence for use in advanced molecular genetics, applied directly to the genetic improvement of this species, such as the establishment of genome-wide selection programs (GWS) in coffee. Recent bioinformatics analyses of complete plant genomes indicate that about 20-30% of the total complete set of genes is novel and specific to each species. That is, these genomic sequences do not exhibit any similarity with those already deposited in global databases and are commonly called "no hits". Recent concepts, called these "no hits" as "orphan genes" and postulate that the emergence of these are the result of adaptive responses specific to each species as a function of stresses and adverse conditions faced by these plants during the evolutionary process. Our work is focused on the identification and functional characterization of orphan genes from coffee, which may have a high potential for innovation and biotechnological applications. This study presents data obtained for some of orphan genes, called CcUnk (Unknown), previously identified in the coffee genome with special focus on CcUnk genes potentially involved in abiotic and biotic-stress responses. Work supported by CAPES-COFECUB, Consórcio Pesquisa Café and INCT-Café (CNPq/FAPEMIG). (Texte intégral

Chemical ecology of echinoderms: Impact of environment and diet in metabolomic profile

The phylum Echinodermata constitutes a successful and widespread group comprising Asteroidea, Ophiuroidea, Echinoidea, Holothuroidea and Crinodeia. Nowadays, marine organisms are being given a lot of attention in drug discovery pipelines. In these studies, sponges and nudibranchs are frequently addressed, however an increasing number of works focus their attention in echinoderms. Given the fact that many of the bioactive molecules found in echinoderms are diet-derived, different feeding behavior and surrounding environment plays a critical role in the chemical composition of echinoderms. In this work, the most relevant chemical classes of small molecules present in echinoderms, such as fatty acids, carotenoids and sterols will be addressed. When data is available, the influence of the environment on the chemical profile of these organisms will be discussed.(undefined

Identificação e caracterização de genes órfãos ("no hits") de café (Coffea canephora ), envolvidos na resposta à seca : [n. 311]

O café é uma planta perene, sendo considerada uma das commodities agrícolas mais importantes do mundo. Por consequencia, visando-se o estabelecimento de ferramentas de auxílio para se acelerar o melhoramento genético desta espécie, avanços significativos em genômica do cafeeiro têm ocorrido nos últimos anos. Como exemplo, pode-se citar a recente conclusão do sequenciamento do genoma completo de Coffea canephora, que servirá de referência para utilização em trabalhos avançados de genética molecular, aplicados diretamente ao melhoramento genético desta espécie, tais como o estabelecimento de programas de seleção genômica ampla (SGA) em cafeeiro. Análises recentes de bioinformática dos genomas completos de plantas indicam que cerca de 20-30% do total de genes de cada genoma são inéditos e específicos de cada espécie. Ou seja, essas sequencias genicas não apresentam similaridade alguma com as já depositadas nas bases de dados mundiais e são comumente denominadas de "no hits". Conceitos recentes, denominam esses "no hits" como "genes órfãos" e postulam que o surgimento dos mesmos são resultantes de respostas adaptativas específicas de cada espécie em função de estresses e condições adversas por essas enfrentadas, durante o processo evolutivo. Nosso trabalho está focado na identificação e caracterização funcional dos genes órfãos de café, por apresentarem alto potencial de inovação e aplicação biotecnológica. O presente estudo apresenta dados obtidos para alguns desses genes orfãos, denominados de CcUnk (Unknown), previamente identificados no genoma de C. canephora e com foco especial àqueles CcUnk genes potencialmente envolvidos na resposta à seca. (Résumé d'auteur

Comparative assessment of atmospheric correction of Landsat imagery using Modtran and dark object subtraction.

Remote sensing by spectral imaging of the Earth's surface can be widely used, but only when the atmospheric influence is nullified and the data are reduced to surface reflectance units. The atmospheric correction referred to here is an atmospheric "compensation" or "characterization" in which algorithms are used in remote sensing applications for hyper and multispectral images to correct atmospheric propagation effects in measurements taken by airborne and orbital systems. The remission of atmospheric effects guarantees the identification of biophysical properties of the targets and their isonomic relationship with spectroradiometric databases, thus enabling the application of sophisticated classification methods such as linear Spectral Mixture Analysis models (SMA) and Spectral Indexes. Based on this premise, the objective of this article is to compare the atmospheric correction used in the MODTRAN model with that used in the Dark Object Subtraction (DOS1) and Improved Dark Object Subtraction (DOS2) models in order to verify which approach shows better correspondence with reference spectral libraries. We used spectral data on tropical soils obtained using the spectroradiometer (FieldSpec Full Resolution). Due to the difficulty in obtaining data on atmospheric conditions, especially for tropical regions, and the difficulty in accessing the most reliable correction procedures, corrections are sometimes disregarded or even based on extremely simple methods which may produce radiance and reflectance estimation errors even greater than tho se of the original images. MODTRAN presented the most consistent results, especially with regard to season variation and the presence of haze (low contrast) in some images due to the high aerosol concentration. This kind of atmospheric phenomenon is common in tropical regions, which shows the importance of considering local atmospheric correction parameters based on an atmosphere simulation model. Methods DO S1 and DOS2, in spite of their good performance in some of the analyzed areas, have not been effective in the suppression of effects related to atmospheric absorption. This work is one of the few that considers different test targets in a tropical environment with season variation

Stabilization of apoptotic cells: generation of zombie cells

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.Apoptosis is characterized by degradation of cell components but plasma membrane remains intact. Apoptotic microtubule network (AMN) is organized during apoptosis forming a cortical structure beneath plasma membrane that maintains plasma membrane integrity. Apoptotic cells are also characterized by high reactive oxygen species (ROS) production that can be potentially harmful for the cell. The aim of this study was to develop a method that allows stabilizing apoptotic cells for diagnostic and therapeutic applications. By using a cocktail composed of taxol (a microtubule stabilizer), Zn2+ (a caspase inhibitor) and coenzyme Q10 (a lipid antioxidant), we were able to stabilize H460 apoptotic cells in cell cultures for at least 72 h, preventing secondary necrosis. Stabilized apoptotic cells maintain many apoptotic cell characteristics such as the presence of apoptotic microtubules, plasma membrane integrity, low intracellular calcium levels and mitochondrial polarization. Apoptotic cell stabilization may open new avenues in apoptosis detection and therapy.This work was supported by FIS PI10/00543 grant, Ministerio de Sanidad, Spain, and Fondo Europeo de Desarrollo Regional (FEDER-Unión Europea), SAS 111242 grant, Servicio Andaluz de Salud-Junta de Andalucía, Proyecto de Investigación de Excelencia de la Junta de Andalucía CTS-5725, BFU2012-38208 and by AEPMI (Asociación de Enfermos de Patología Mitocondrial).Peer Reviewe

Produção in vivo de embriões caprinos da raça Moxotó participando de um programa de preservação.

Edição dos resumos da 20. Reunião Anual da Sociedade Brasileira de Tecnologia de Embriões, Araxá, MG, agosto 2006

Lymphocyte subsets in human immunodeficiency virus-unexposed Brazilian individuals from birth to adulthood

Ethnic origin, genetics, gender and environmental factors have been shown to influence some immunologic indices, so that development of reference values for populations of different backgrounds may be necessary. We have determined the distribution of lymphocyte subsets in healthy Brazilian individuals from birth to adulthood. Lymphocyte subsets were determined using four-colour cytometry in a cross-sectional study of 463 human immunodeficiency virus-unexposed children and adults from birth through 49 years of age. Lymphocyte subsets varied according to age, as previously observed in other studies. However, total CD4+ T cell numbers were lower than what was described in the Pediatric AIDS Clinical Trials Group P1009 (PACTG P1009), which assessed an American population of predominantly African and Hispanic backgrounds until the 12-18 year age range, when values were comparable. Naïve percentages and absolute values of CD8+ T cells, as assessed by CD45RA expression, were also lower than the PACTG P1009 data for all analysed age ranges. CD38 expression on both CD4+ and CD8+ T cells was lower than the PACTG P1009 values, with a widening gap between the two studies at older age ranges. Different patterns of cell differentiation seem to occur in different settings and may have characteristic expression within each population.Universidade Federal de São Paulo (UNIFESP) Departamento de MedicinaCentro Assistencial Cruz de MaltaUniversidade Federal de São Paulo (UNIFESP) Departamento de PediatriaUNIFESP, Depto. de MedicinaUNIFESP, Depto. de PediatriaSciEL