TECNOLOGIAS PARA A CONSERVAÇÃO EX SITU DE GERMOPLASMA DE AMBURANA CEARENSIS (FR. ALL.) A. C. SMITH - PAPILIONACDEAE

A cerejeira, Amburana cearensis, é uma das espécies florestais tropicais mais exploradas pela indústria madeireira. Sua reprodução é sexuada e seu ciclo de frutificação é bianual em alguns locais do Brasil Central. As sementes, na natureza, proporcionam uma baixa regeneração natural da espécie, visto que seu poder germinativo é efêmero. Essas peculiaridades dificultam sua conservação "in situ", A fim de se obter subsídios para a conservação "ex situ" da espécie, realizaram-se testes de germinação de sementes e avaliação de sobrevivência das mudas no campo. Sementes de catorze progênies provenientes de seis municípios do vale do rio Paraná, estado de Goiás, foram submetidas simultaneamente a testes de germinação em laboratório e em viveiro. A porcentagem de germinação sob condições de laboratório foi superior àquela sob condições de viveiro. A porcentagem de sobrevivência das mudas no campo, após cinco meses de plantio em Banco Ativo, foi quase total. Os baixos valores de grau de umidade das sementes (X = 7,5%) sugerem que a espécie possui semente ortodoxa e, portanto, a mesma é passível de ser conservada em Bancos de Germoplasma convencionais

On the temperature behavior of shunt-leakage currents in Cu(In,Ga)Se2 solar cells: The role of grain boundaries and rear Schottky contact

By comparing simulated and measured dark current-voltage (I-V) characteristics of CIGS cells at different temperatures, we investigate the temperature behavior of the shunt leakage current, and find that it can be explained by large donor trap concentrations at grain boundaries (GBs), and by a Schottky barrier at the backside contact where the GBs meets the anode metallization. We studied the I-V characteristics in the temperature range 280 K - 160 K achieving good fits of the measured I-V curves, especially for reverse bias and low forward bias, where the shunt leakage current dominates. The most important parameters determining the shunt leakage current value and its temperature dependence are the peak energy and density of the GB donor distribution, which control the inversion of GBs and the pinning of Fermi level at the anode/GB contact

Mutations in blind cavefish target the light-regulated circadian clock gene, period 2

Light represents the principal signal driving circadian clock entrainment. However, how light influences the evolution of the clock remains poorly understood. The cavefish Phreatichthys andruzzii represents a fascinating model to explore how evolution under extreme aphotic conditions shapes the circadian clock, since in this species the clock is unresponsive to light. We have previously demonstrated that loss-of-function mutations targeting non-visual opsins contribute in part to this blind clock phenotype. Here, we have compared orthologs of two core clock genes that play a key role in photic entrainment, cry1a and per2, in both zebrafish and P. andruzzii. We encountered aberrantly spliced variants for the P. andruzzii per2 transcript. The most abundant transcript encodes a truncated protein lacking the C-terminal Cry binding domain and incorporating an intronic, transposon-derived coding sequence. We demonstrate that the transposon insertion leads to a predominantly cytoplasmic localization of the cavefish Per2 protein in contrast to the zebrafish ortholog which is distributed in both the nucleus and cytoplasm. Thus, it seems that during evolution in complete darkness, the photic entrainment pathway of the circadian clock has been subject to mutation at multiple levels, extending from opsin photoreceptors to nuclear effectors

High genetic diversity within and among bitter cassava cultivated in three soil types in Central Amazonia.

Bitter cassava is an important food crop that was domesticated in Amazonia. Although it is exclusively propagated by stem cuttings, cassava retained its ability of sexual reproduction. The occurrence and incorporation of sexual plants into the stock of clonal varieties contributes to the high genetic diversity observed within the crop. Despite being well adapted to nutrient deprived soils of Amazonia, ethnobotanical observations showed that communities of smallholder farmers along the middle Madeira River, in Central Amazonia, also cultivate cassava in the highly fertile soils of the floodplains and Amazonian dark earths (ADE). These farmers grow different sets of varieties in each soil type, which may also contribute to the maintenance of high levels of genetic diversity within the crop. We evaluated with 10 nuclear microsatellite markers the genetic diversity within and among some of the most commonly cultivated bitter cassava varieties grown on ADE, floodplain and Oxisols soils in the middle Madeira region. High levels of genetic diversity within varieties were observed (HO ranging from 0.495 to 0.707, and HE ranging from 0.250 to 0.460). Additionally, varieties were generally highly differentiated from each other. Although high levels of genetic diversity were previously observed in studies carried out in regions of low soil fertility in other parts of Amazonia, we identified that management of different soil types is important to the maintenance of genetically distinct stocks of varieties, which also contributes to the maintenance of the genetic diversity within the crop

Aplicações preventivas de inseticidas intensificam o ataque do percevejo-marrom Euschistus heros em soja.

Objetivo: avaliar o efeito do manejo de pragas com aplicações preventivas de inseticidas para lagartas e percevejos sobre a densidade populacional de E. heros no início da fase crítica de dano desta praga a soja

Postural Control in Children with Cerebellar Ataxia

Controlling posture, i.e., governing the ensemble of involuntary muscular activities that manage body equilibrium, represents a demanding function in which the cerebellum plays a key role. Postural activities are particularly important during gait initiation when passing from quiet standing to locomotion. Indeed, several studies used such motor task for evaluating pathological conditions, including cerebellar disorders. The linkage between cerebellum maturation and the development of postural control has received less attention. Therefore, we evaluated postural control during quiet standing and gait initiation in children affected by a slow progressive generalized cerebellar atrophy (SlowP) or non-progressive vermian hypoplasia (Joubert syndrome, NonP), compared to that of healthy children (H). Despite the similar clinical evaluation of motor impairments in NonP and SlowP, only SlowP showed a less stable quiet standing and a shorter and slower first step than H. Moreover, a descriptive analysis of lower limb and back muscle activities suggested a more severe timing disruption in SlowP. Such differences might stem from the extent of cerebellar damage. However, literature reports that during childhood, neural plasticity of intact brain areas could compensate for cerebellar agenesis. We thus proposed that the difference might stem from disease progression, which contrasts the consolidation of compensatory strategies

Response of microchannel plates to single particles and to electromagnetic showers

We report on the response of microchannel plates (MCPs) to single relativistic particles and to electromagnetic showers. Particle detection by means of secondary emission of electrons at the MCP surface has long been proposed and is used extensively in ion time-of-flight mass spectrometers. What has not been investigated in depth is their use to detect the ionizing component of showers. The time resolution of MCPs exceeds anything that has been previously used in calorimeters and, if exploited effectively, could aid in the event reconstruction at high luminosity colliders. Several prototypes of photodetectors with the amplification stage based on MCPs were exposed to cosmic rays and to 491 MeV electrons at the INFN-LNF Beam-Test Facility. The time resolution and the efficiency of the MCPs are measured as a function of the particle multiplicity, and the results used to model the response to high-energy showers.Comment: Paper submitted to NIM

Antiviral activity of fecal water samples from HIV-1 infected subjects treated with a specific probiotic formulation

Objectives: The aim of the study was to investigate if the supplementation with multistrain probiotics may be able to modulate T cell response in HIV-1 infected patients and to evaluate the anti-HIV activity of probiotic by studying fecal water (FW) samples. Methods: Three HIV-1-positive patients (Pt1, Pt2 and Pt3) on long-term suppressive combined antiretroviral therapy (cART) received a specific multi-strain probiotic supplementation (Vivomixx ®), for six months (T6). Levels of T cell subsets were evaluated by flow cytometry. Anti- HIV activity of FW samples was evaluated in vitro. Results: CD4+ T cells levels increased in all HIV-1 infected patients whereas activation markers (CD38 and HLA-DR) were decreased both on CD4+ and CD8+ T cells. FW samples presented an increased inhibitory activity against HIV-1 compared to T0 (FW-Pt1: T0 =40%, T6 = 65% of reduction; FW Pt2: T0 = 26%, T6 = 46% of reduction; FW Pt3: T0 = 47%, T6 = 94% of reduction). Discussion: Our data suggest that the administration of the specific probiotic formulation improves the antiviral status of people living with HIV-1 under cART, also modulating T cell response. Conclusion: Anti-HIV activity of FW may have several public health and social implications for sexually transmitted diseases that need to be further explored

Performance of a Tungsten-Cerium Fluoride Sampling Calorimeter in High-Energy Electron Beam Tests

A prototype for a sampling calorimeter made out of cerium fluoride crystals interleaved with tungsten plates, and read out by wavelength-shifting fibres, has been exposed to beams of electrons with energies between 20 and 150 GeV, produced by the CERN Super Proton Synchrotron accelerator complex. The performance of the prototype is presented and compared to that of a Geant4 simulation of the apparatus. Particular emphasis is given to the response uniformity across the channel front face, and to the prototype's energy resolution.Comment: 6 pages, 6 figures, Submitted to NIM