Pesquisas com espécies do gênero Prosopis no Semi-árido brasileiro.

O trabalho descreve pesquisas desenvolvidas e resultados obtidos pela Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA)/Instituto Brasileiro de Desenvolvimento Florestal (IBDF), através do Programa Nacional de Pesquisa Florestal (PNPF), com espécies do gênero Prosopis, na região Nordeste do Brasil. Participam na execução deste programa o Centro de Pesquisa Agropecuária do Trópico Semi - Árido (CPATSA), Empresa Estadual de Pesquisa Agropecuária da Paraíba (EMEPA) e Empresa de Pesquisa Agropecuária do Rio Grande do Norte (EMPAR,l), com ensaios instalados nos estados de Pernambuco, Paraíba, Rio Grande do Norte e Bahia. As pesquisas com Prosopis abrangem ensaios de competição de espécies, progênies, propagação vegetativa, extração de sementes e rmazenamento, espaçamentos, produtividade madeireira e de vagens, e agrosilvicultura. As espécies atualmente em estudo são: P.alba, P. chilensis, P. glandulosa, P. juliflora, P. pallida, P. tamarugo e P. velutina.bitstream/item/132951/1/37550-1.pd

Performance of species of the genus Prosopis at 24 monts of age in Petrolina.

The medium and long-term afforestation efforts with P. juliflora in the Brazilian Northeast, using P. juliflora seeds produced in the region itself, must take into account potential restrictions due to inbreeding problems, as pointed out by pires and Kageyama (1985). These authors, in studies conducred on a population in Soledade and included elsewhere in this book, found low heritability and genetic variability coefficients for height and DBH among families, in open-pollinated progeny trials. The need of enlarging the genetic base and gathering data on the performance of other species of Prosopis in the Brazilian semi-arid region prompted the National Forestry Research Progrma (PNPF), through the Agriculture and Livestock Research Center for the Semi-Arid Tropic (CPATSA), to introduce other species of this genus into the region. This paper describes the initial performance of P. alba, P. chilensis, P. pallida, P. velutina, P. gradulosa var, torryana, P. tamarugo and P. juliflora in Petrolina, Pernambuco, 24 months after planting, with the purpose of selecting those species which seem promising for firewood and/or fodder production

A Bayesian estimate of the CMB-large-scale structure cross-correlation

Evidences for late-time acceleration of the Universe are provided by multiple probes, such as Type Ia supernovae, the cosmic microwave background (CMB) and large-scale structure (LSS). In this work, we focus on the integrated Sachs--Wolfe (ISW) effect, i.e., secondary CMB fluctuations generated by evolving gravitational potentials due to the transition between, e.g., the matter and dark energy (DE) dominated phases. Therefore, assuming a flat universe, DE properties can be inferred from ISW detections. We present a Bayesian approach to compute the CMB--LSS cross-correlation signal. The method is based on the estimate of the likelihood for measuring a combined set consisting of a CMB temperature and a galaxy contrast maps, provided that we have some information on the statistical properties of the fluctuations affecting these maps. The likelihood is estimated by a sampling algorithm, therefore avoiding the computationally demanding techniques of direct evaluation in either pixel or harmonic space. As local tracers of the matter distribution at large scales, we used the Two Micron All Sky Survey (2MASS) galaxy catalog and, for the CMB temperature fluctuations, the ninth-year data release of the Wilkinson Microwave Anisotropy Probe (WMAP9). The results show a dominance of cosmic variance over the weak recovered signal, due mainly to the shallowness of the catalog used, with systematics associated with the sampling algorithm playing a secondary role as sources of uncertainty. When combined with other complementary probes, the method presented in this paper is expected to be a useful tool to late-time acceleration studies in cosmology.Comment: 21 pages, 15 figures, 4 tables. We extended the previous analyses including WMAP9 Q, V and W channels, besides the ILC map. Updated to match accepted ApJ versio

An accurate formula for the period of a simple pendulum oscillating beyond the small-angle regime

A simple approximation formula is derived here for the dependence of the period of a simple pendulum on amplitude that only requires a pocket calculator and furnishes an error of less than 0.25% with respect to the exact period. It is shown that this formula describes the increase of the pendulum period with amplitude better than other simple formulas found in literature. A good agreement with experimental data for a low air-resistance pendulum is also verified and it suggests, together with the current availability/precision of timers and detectors, that the proposed formula is useful for extending the pendulum experiment beyond the usual small-angle oscillations.Comment: 15 pages and 4 figures. to appear in American Journal of Physic

Awaking the vacuum with spheroidal shells

It has been shown that well-behaved spacetimes may induce the vacuum fluctuations of some nonminimally coupled free scalar fields to go through a phase of exponential growth. Here, we discuss this mechanism in the context of spheroidal thin shells emphasizing the consequences of deviations from spherical symmetry.Comment: 10 pages, 7 figures. Minor changes, version published on Phys. Rev.

Comportamento do tamarix (Tamarix sp. - Tamaricaceae) na recuperação de áreas degradadas por mineração.

As atividades de mineração alteram as áreas naturais pelo acúmulo de rejeitos finos e estéreis e pela retirada da camada superior de solo, causando impactos ambientais indesejáveis. Para reduzir estes danos, vem sendo realizado o plantio de espécies arbóreas e arbustivas para a recuperação das áreas degradadas. O presente trabalho teve como objetivo, avaliar o comportamento do tamarix (Tamarixsp.) em ensaio de seleção de espécies florestais na recuperação de área da barragem de rejeito da Mineração Caraíba S/A, situada no município de Jaguarari, Bahia, região semi-árida do Nordeste do Brasil. O tamarix foi introduzido do Peru, pela Embrapa Semi-Árido na década de 80, sendo utilizado na formação de quebra-ventos em regiões desérticas

Regeneração de algarobeiras em área de mata ciliar do rio de Contas, em Manoel Vitorino-BA.

O estudo teve como objetivo analisar a estrutura vegetal de áreas da Caatinga com a presença da algaroba