Strategy for selection of soybean genotypes tolerant to drought during germination

Water deficit is the main reason for instability in the context of soybean culture. The development of strategies for the selection of more tolerant genotypes is necessary. These strategies include the use of polyethylene glycol 6000 solutions (PEG-6000) for conducting the germination test under conditions of water restriction. Thus, the objective of this study was to determine the osmotic potential and the main characteristics that promote the discrimination of soybean genotypes with regard to water stress tolerance during germination and the vigor test. Thirteen soybean cultivars were used. The seeds were allowed to germinate on sheets of germitest paper moistened in solution with PEG-6000, simulating different levels of water availability, which is expressed as osmotic potential (0.0, -0.2, -0.4, and -0.6 MPa). We assessed germination, length, and dry mass for seedlings and seeds, as well as reserve dynamics. Germination and variables related to the dynamics of reservation have great influence on the expression of variability in environments under stress. Among the different osmotic potentials, the -0.2 MPa was the most efficient for the expression of genetic variability among the cultivars. Conducting the germination test with PEG-6000 solution to -0.2 MPa was efficient for selecting soybean cultivars tolerant to water stress. This was accomplished by evaluating the percentage of germination, along with variables related to the dynamics of reservation

Influência no processo de inserção social de jovens multiproblemáticos : o caso do CDIJ Perkursos

Dissertação de Mestrado, Sociologia, 17 de Abril de 2015, Universidade dos Açores.A presente investigação subordinada à temática "Influência no processo de inserção social de jovens multiproblemáticos: o caso do CDIJ Perkursos", decorre da curiosidade em saber e perceber onde estão e como estão os jovens que foram intervencionados neste centro. Através de uma análise aos processos dos jovens, onde constam as características que levam estes jovens a fazerem parte do centro e de um conjunto de entrevistas semiestruturadas, a investigação alicerça-se na seguinte pergunta de partida: "Em que medida a passagem dos jovens multiproblemáticos, pelo Centro de Inclusão Juvenil Perkursos, influenciou as trajetórias de vida sob o ponto de vista social, pessoal e profissional?". Verificámos que, de facto, há uma relação entre o ter frequentado o centro e as inflexões das suas trajetórias de vida após esta frequência. Assim, são jovens que destacam a importância de ter frequentado o centro para a conclusão do 9º ano de escolaridade, a influência de terem tido a formação em contexto de trabalho para a escolha da atual profissão e terem ultrapassado alguns dos problemas que tinham quando entraram no CDIJ. Nesta linha, e apesar de serem jovens que abandonaram o ensino regular por falta de identificação com este, conseguiram concluir o 9º ano através de uma resposta social alternativa que possibilitou uma melhor inserção social.ABSTRACT: The present investigation is subordinated to the theme "Influence on social integration process of multichallenged younghters: the case of CDIJ Perkursos", stems from curiosity to know and understand where and how are young people who have been intervened in this center. Through an analysis of the processes of the young, that contain the features that led them to be a part of the center and a set of semi-structured interviews, the research was founded on the following initial question: "To what extent the passage of multichallenged younghsters by the Center for Youth Inclusion Perkursos influenced their life trajectories from the social, personal and professional point of view?". We found that there is indeed a relation between having attended the center and the inflections of their life trajectories after this frequency. These young highlight the importance of having attended the center for completing the 9th grade, the influence they have had training in the context of work for the current choice of profession and have surpassed some of the problems they had when they entered the CDIJ. In this line of thinking, and although they are young people who have left the regular school due to lack of identification with this, they have managed to complete the 9th grade through an alternative social response which enabled a better social integration

The influence of habitat and species attributes on the density and nest spacing of a stingless bee (Meliponini) in the Atlantic Rainforest.

T. spinipes lives in perennial eusocial colonies and builds nests exposed on tree branches. Why this habitat generalist with exposed nests cannot nest successfully in forest habitats is intriguing. This study explores the hypothesis this species reaches higher densities in vegetation with open canopies and the subsidiary shading hypothesis, assuming the failure of exposed nests in closed canopy rainforest. As this species shows the basic attributes of territorial foraging groups, the hypothesis of uniform nest spacing is also tested. Comparative field data on nest density and spacing in open canopy vegetation and adjacent closed canopy forest are used to test these hypotheses. In random 40 20x200m plots in rubber groves, 18 nests were recorded. This nest density for a single stingless bee was approximately 36 times higher than in the adjacent rainforest. The high density of nests in the rubber groves is also associated with a regular spatial distribution of nests. The ostensive patrolling distances from the colonies probably operates at short distances, which still corresponds to large territorial areas for such a small stingless bee.We conclude that: this species faces powerful nesting constraints in the ever green and closed canopy of rainforest habitats; as the nest density approaches the density threshold, the patrolling mechanism regulates access to prospective nest sites; the high availability of sunny sites for nesting within the deciduous and open canopy of rubber trees favours the high nest density of T. spinipes and its wide spread distribution where this agroforestry system dominates.

Tree species used for nesting by stingless bees (Hymenoptera: Apidae: Meliponini) in the Atlantic Rain Forest (Brazil): Availability or Selectivity

The stingless bees (Meliponini) are numerically dominant in tropical forests and most species depend on preexisting cavities for nesting, mainly tree hollows. However, it is still incipient the knowledge about basic characteristics of forest trees used for nesting. The basic questions addressed in this study include: would appropriate hollows be restricted to a few tree species? Would there be selectivity in the use of tree hollows in the forest? These issues are addressed from the comparison of usage patterns among forest trees in different stages of forest regeneration in the Atlantic Forest (Michelin Reserve in northeastern Brazil). Among 89 nests (from six species) found in tree hollows, in a sampled area of 32 ha of forests, 78.7% were associated with live plants and 21.3% to dead trees. This result does not support the hypothesis of selectivity for living trees, considering the high rate of living trees: dead trees (40:1). Nests were sampled from 41 tree species of 31 genera and 22 plant families. Meliponini species showed no differential association with any tree species. The absence of selectivity of tree species as nesting site is probably due to the high diversity of trees per hectare of Atlantic rainforest. The stingless bees also showed no selectivity for wood hardness, therefore the potential durability of tree hollows probably exerts weak selective pressure on bees, or at least the hardness variation range of trees used for nesting has no important influence on reproductive success of the colonies of stingless bees

Fermions in a warped resolved conifold

AbstractWe investigated the localization of the spinorial field in a braneworld built as a warped product between a 3-brane and a 2-cycle of the resolved conifold. This scenario provides a geometric flow that controls the singularity at the origin and changes the properties of the fermion in this background. Furthermore, due the cylindrical symmetry according to the 3-brane and a smoothed warp factor, this geometry can be regarded as a near brane correction of the string-like branes. This geometry allows a normalizable and well-defined massless mode whose decay and value on the brane depend on the resolution parameter. For the Kaluza–Klein modes, resolution parameter also controls the height of the barrier of the volcano potential