Toward in vitro fertilization in Brachiaria spp.

Brachiaria are forage grasses widely cultivated in tropical areas. In vitro pollination was applied to accessions of Brachiaria spp. by placing pollen of non-dehiscent anthers on a solid medium near isolated ovaries. Viability and in vitro germination were tested in order to establish good conditions for pollen development. Comparing sexual to apomictic plants, apomictic pollen has more abortion after meiosis during the microspore stage and a lower viability and, of both types, only some plants have sufficient germination in a high sugar concentration. Using in vitro pollination with the sexual plant, the pollen tube penetrates into the nucellus and micropyle, but the embryo sac degenerates and collapses. In the apomictic B. decumbens, in vitro pollination leads to the transfer of the sperm nuclei into the egg cell and the central cell. The results are discussed according to normal fertilization and barriers in sexual and apomictic plants

Developing intelligent environments with OSGi and JADE

Series: IFIP International Federation for Information ProcessingThe development of intelligent environments poses complex challenges, namely at the level of device heterogeneity and environment dynamics. In fact, we still lack supporting technologies and development approaches that can efficiently integrate different devices and technologies. In this paper we present how a recent integration of two important technologies, OSGi and Jade, can be used to significantly improve the development process, making it a more dynamic, modular and configurable one. We also focus on the main advantages that this integration provides to developers, from the Ambient Intelligence point of view. This work results from the development of two intelligent environments: VirtualECare, which is an intelligent environment for the monitorization of elderly in their homes and UMCourt, a virtual environment for dispute resolution.The work described in this paper is included in TIARAC - Telematics and Artificial Intelligence in Alternative Conflict Resolution Project (PTDC/JUR/71354/2006), which is a research project supported by FCT (Science & Technology Foundation), Portugal

Equality of opportunity and educational achievement in Portugal

Portugal has one of the highest levels of income inequality in Europe, and low wages and unemployment are concentrated among low skill individuals. Education is an important determinant of inequality. However, there are large differences in the educational attainment of different individuals in the population, and the sources of these differences emerge early in the life-cycle when families play a central role in individual development. We estimate that most of the variance of school achievement at age 15 is explained by family characteristics. Observed school inputs explain very little of adolescent performance. Children from highly educated parents benefit of rich cultural environments in the home and become highly educated adults. Education policy needs to be innovative: (1) it needs to explicitly recognize the fundamental long run role of families on child development; (2) it needs to acknowledge the failure of traditional input based policies

Vortex-line liquid phases: Longitudinal superconductivity in the lattice London model

We study the vortex-line lattice and liquid phases of a clean type-II superconductor by means of Monte Carlo simulations of the lattice London model. Motivated by a recent controversy regarding the presence, within this model, of a vortex-liquid regime with longitudinal superconducting coherence over long length scales, we directly compare two different ways to calculate the longitudinal coherence. For an isotropic superconductor, we interpret our results in terms of a temperature regime within the liquid phase in which longitudinal superconducting coherence extends over length scales larger than the system thickness studied. We note that this regime disappears in the moderately anisotropic case due to a proliferation, close to the flux-line lattice melting temperature, of vortex loops between the layers.Comment: 8 pages, Revtex, with eps figures. To appear in Phys. Rev.

Avaliação do potencial alelopático de três espécies de Eucalyptus na germinação de espécies cultivadas e nativas do cerrado.

Realizaram-se ensaios de germinação com sementes de Lactuca sativa L. (alface) cv. Aurélia, sorgo cv. BR 304, Anadenanthera peregrina (L.) Speg. (angico) e Enterolobium contortisiliquum (Vell.) (tamboril), com o objetivo de avaliar o potencial alelopático de extratos aquosos foliares de três espécies de Eucalyptus. Prepararam-se os extratos colocando as folhas senescentes, secas e moídas de E. camaldulensis Dehnh (EC), E. grandis W.Hill ex Maien (EG) e E. urophylla S.T.Blake (EU) em água destilada na concentração 5% (p/v). Após agitados e centrifugados, obtiveram-se extratos a 100% (v/v), com os quais diluiram-se para 75, 50, 25, 12,5, 0% (v/v) e medidos o pH e o potencial osmótico em cada concentração. As sementes foram colocadas para germinar em placas gerbox, forradas com papel de filtro e umedecidas com os extratos, numa amostragem de 100 sementes por tratamento (4x25). As placas foram colocadas em câmara germinadora a 25°C, na presença de luz. A germinação foi verificada a cada 48h, durante 7 dias, sendo o critério germinativo a emergência radicular. O pH dos extratos das três espécies de Eucalyptus diminuiu com o aumento da concentração, porém, não afetou a germinação das espécies receptoras testadas. Os extratos aquosos de folhas de EC, EG e EU não interferiram na germinação das sementes de angico, tamboril e sorgo, porém inibiram a germinação das sementes de alface. Eucalyptus camaldulensis; E; grandis; E; urophyll