Comportement agronomique d'une collection de pois (Pisum sativum L)

Agronomical Behaviour of a Pea Collection (Pisum sativum L.). This experience was achieved under greenhouse conditions. Twelve genotypes of pea were used (Asgrow, Jumbo, Lincoln, Merveille de Kelvedon, Purser, Rajai Torpe, Snajor Kosep, Korai,Wando, Rondo, local genotype, Major Kosep Korai and Surgevil). They were cultivated on peat during 5.5 months (from October to April). Some agronomical parameters were studied: resistance to diseases, (Powdery-mildew, mildew, top yellow virus, anthracnose, browning), fresh matter, number of branches/plant, number of flowers/plant, number of pods/ plant and the yield of grains /plant. Results showed that only the genotype Purser is resistant to all diseases and Surgevil is sensitive only to the Top Yellow virus. The local genotype is sensitive to three frequent diseases (Powdery-mildew, mildew and Anthracnose). With regard to vegetative growth, the highest yield of fresh matter do not contribute towards a high fertility rate. In fact, only the genotypes having a weak yield of fresh matter (Snajor Kosep Korai, Asgrow, Major Kosep Korai, Rajai Torpe and Purser) have the most important rate of fertility (> 30%). Within this group, the most important yield (> 9 g/plant) is a result of high: number of pods/plant (7.5 to 21.6) and of grains/pod (2.8 to 4.92). Finally, genotype Purser should be retained for farmers and programs of genetic amelioration for its resistance to diseases and agronomical performances

Genetic Relationship between Cocirculating Human Enteroviruses Species C

Recombination events between human enteroviruses (HEV) are known to occur frequently and to participate in the evolution of these viruses. In a previous study, we reported the isolation of a panel of viruses belonging to the Human enterovirus species C (HEV-C) that had been cocirculating in a small geographic area of Madagascar in 2002. This panel included type 2 vaccine-derived polioviruses (PV) that had caused several cases of acute flaccid paralysis in humans. Previous partial sequencing of the genome of these HEV-C isolates revealed considerable genetic diversity, mostly due to recombination. In the work presented herein, we carried out a more detailed characterization of the genomes of viruses from this collection. First, we determined the full VP1 sequence of 41 of these isolates of different types. These sequences were compared with those of HEV-C isolates obtained from other countries or in other contexts. The sequences of the Madagascan isolates of a given type formed specific clusters clearly differentiated from those formed by other strains of the same type isolated elsewhere. Second, we sequenced the entire genome of 10 viruses representing most of the lineages present in this panel. All but one of the genomes appeared to be mosaic assemblies of different genomic fragments generated by intra- and intertypic recombination. The location of the breakpoints suggested potential preferred genomic regions for recombination. Our results also suggest that recombination between type HEV-99 and other HEV-C may be quite rare. This first exhaustive genomic analysis of a panel of non-PV HEV-C cocirculating in a small human population highlights the high frequency of inter and intra-typic genetic recombination, constituting a widespread mechanism of genetic plasticity and continually shifting the HEV-C biodiversity

Diazoxide Promotes Oligodendrocyte Precursor Cell Proliferation and Myelination

Several clinical conditions are associated with white matter injury, including periventricular white matter injury (PWMI), which is a form of brain injury sustained by preterm infants. It has been suggested that white matter injury in this condition is due to altered oligodendrocyte (OL) development or death, resulting in OL loss and hypomyelination. At present drugs are not available that stimulate OL proliferation and promote myelination. Evidence suggests that depolarizing stimuli reduces OL proliferation and differentiation, whereas agents that hyperpolarize OLs stimulate OL proliferation and differentiation. Considering that the drug diazoxide activates K(ATP) channels to hyperpolarize cells, we tested if this compound could influence OL proliferation and myelination.Studies were performed using rat oligodendrocyte precursor cell (OPC) cultures, cerebellar slice cultures, and an in vivo model of PWMI in which newborn mice were exposed to chronic sublethal hypoxia (10% O(2)). We found that K(ATP) channel components Kir 6.1 and 6.2 and SUR2 were expressed in oligodendrocytes. Additionally, diazoxide potently stimulated OPC proliferation, as did other K(ATP) activators. Diazoxide also stimulated myelination in cerebellar slice cultures. We also found that diazoxide prevented hypomyelination and ventriculomegaly following chronic sublethal hypoxia.These results identify KATP channel components in OLs and show that diazoxide can stimulate OL proliferation in vitro. Importantly we find that diazoxide can promote myelination in vivo and prevent hypoxia-induced PWMI

Interspecific variation in the relationship between clutch size, laying date and intensity of urbanization in four species of hole-nesting birds

The increase in size of human populations in urban and agricultural areas has resulted in considerable habitat conversion globally. Such anthropogenic areas have specific environmental characteristics, which influence the physiology, life history, and population dynamics of plants and animals. For example, the date of bud burst is advanced in urban compared to nearby natural areas. In some birds, breeding success is determined by synchrony between timing of breeding and peak food abundance. Pertinently, caterpillars are an important food source for the nestlings of many bird species, and their abundance is influenced by environmental factors such as temperature and date of bud burst. Higher temperatures and advanced date of bud burst in urban areas could advance peak caterpillar abundance and thus affect breeding phenology of birds. In order to test whether laying date advance and clutch sizes decrease with the intensity of urbanization, we analyzed the timing of breeding and clutch size in relation to intensity of urbanization as a measure of human impact in 199 nest box plots across Europe, North Africa, and the Middle East (i.e., the Western Palearctic) for four species of hole-nesters: blue tits (Cyanistes caeruleus), great tits (Parus major), collared flycatchers (Ficedula albicollis), and pied flycatchers (Ficedula hypoleuca). Meanwhile, we estimated the intensity of urbanization as the density of buildings surrounding study plots measured on orthophotographs. For the four study species, the intensity of urbanization was not correlated with laying date. Clutch size in blue and great tits does not seem affected by the intensity of urbanization, while in collared and pied flycatchers it decreased with increasing intensity of urbanization. This is the first large-scale study showing a species-specific major correlation between intensity of urbanization and the ecology of breeding. The underlying mechanisms for the relationships between life history and urbanization remain to be determined. We propose that effects of food abundance or quality, temperature, noise, pollution, or disturbance by humans may on their own or in combination affect laying date and/or clutch size

Exploring the Human Handwriting Process

The study of human handwriting movements is of great interest to researchers and biologists. It can lead to an understanding of the properties of the biological system that generates the human handwriting movements. With the identification of a dynamical system that exhibits characteristics similar to the biological one, it is possible to study handwriting movements, to identify their driving motor signals and to try to reproduce by machine the handwriting motion. In this paper, we give an analysis of modeling techniques for the handwriting process proposed in the literature. We show that either mathematical models based on the trajectories of handwritten objects or physical models obtained from the dynamic motion of the human hand can be used for modeling the handwriting process. We study the handwriting movements using these approaches and we give an analysis and synthesis of the driving motor signals. We apply the results to the generation of handwritten Arabic letters. We then propose a new synthesis technique where a more promising and realistic model can be obtained. We present the basic idea and expect that some improvement over the previous techniques can be obtained. The technique is based on Feedback Error Learning neural networks

Comparison of the biology, dynamics, and secondary production of Talorchestia brito (Amphipoda, Talitridae) in Atlantic (Portugal) and Mediterranean (Tunisia) populations

The biology, population dynamics, and production of Talorchestia brito were studied at two sandy beaches located on the Atlantic (Portugal) and on the Mediterranean (Tunisia) coasts, respectively. The seasonal variation in abundance and the overall densities were similar in both populations. Reproduction occurred from February to September in the Atlantic, and from March to early November in the Mediterranean. The sex ratio was male biased in the Atlantic, and female biased in the Mediterranean. Based on data from the Atlantic population, both abundance and the proportion of reproductive females were positively correlated with temperature, while the proportion of juveniles in the population was positively correlated with temperature and sediment moisture. On average, individuals from the Atlantic were larger than the ones from the Mediterranean. Life span was estimated at six to nine months in the Atlantic, and five to eight months in the Mediterranean. Talorchestia brito was shown to be a semiannual species, with iteroparous females producing two broods per year, and exhibited a bivoltine life cycle. The minimum age required for males' and females' sexual differentiation and for female sexual maturation was shorter in the Mediterranean. Growth production (P) was estimated at 0.19 g m-2 y-1 ash free dry weight (AFDW; 4.3 kJ m-2 y-1) in the Atlantic population, and 0.217 g m-2 y-1 AFDW (4.9 kJ m-2 y-1) in the Mediterranean one. Elimination production (E) was estimated at 0.35 g m-2 y-1 AFDW (7.9 kJ m-2 y-1) in the Atlantic, and 0.28 g m-2 y-1 AFDW (6.3 kJ m-2 y-1) in the Mediterranean. The average annual biomass () (standing stock) was estimated at 0.032 g m-2 in the Atlantic beach, and 0.029 g m-2 in the Mediterranean one, resulting, respectively, in ratios of 5.9 and 7.5 and ratios of 10.8 and 9.6. Like other talitrids, T. brito exhibited geographic variation in morphometrical characteristics, sex ratio, growth rates, life span, and reproduction period, with the Atlantic population presenting a slower life history.http://www.sciencedirect.com/science/article/B6WDV-49W2MK0-8/1/00a2b4f13d40cd8c6d6f3968e658134

Comparison of terrestrial isopod (Crustacea: Oniscidea) assemblages from two preserved areas (Bouhedma and Chambi) in arid regions

A total of 1290 specimens belonging to 11 species and four families were captured in two national parks, Bouhedma and Chambi. Among these species, seven belonged to Porcellionidae, and the remaining species represented Agnaridae, Armadillidae and Armadillidiidae families. Five species were common and recorded in both parks. However, Armadillidium tunisiense, Hemilepistus reaumurii and Porcellio djahizi were recorded only in Chambi while Agabiformius lentus, Armadillo officinalis and Porcellio albinus were collected only in Bouhedma. The distribution structure of the collected species was analyzed according to altitude and plant assemblages. Seasonal sampling showed that the highest abundance and species richness were recorded in spring. In both parks, the species richness decreased as the altitude increased. Arid regions sheltered specific species such as H. reaumurii and P. albinus, which were often the dominant component of the arthropod macrodecomposer guild in some habitats. The similarity analysis showed a quantitative and qualitative difference between the two parks. The two parks Bouhedma and Chambi shared five species (Leptotrichus panzerii, Porcellio laevis, P. variabilis, Porcellionides pruinosus, Armadillidium sulcatum) with areas studied in the north of Tunisia, Kroumirie, supralittoral zones and around the wetlands