Testes de envelhecimento precoce para sementes de bracatinga (Mimosa scabrella Benth).

O trabalho objetiva determinar as melhores temperaturas e tempos de exposição dentro da camara para a realização do teste de envelhecimento precoce de sementes de Bracatinga (Mimosa scabrella Benth).bitstream/item/96269/1/CPAF-AP-2000-Teste-Bracatinga.pd

Critical regime of two dimensional Ando model: relation between critical conductance and fractal dimension of electronic eigenstates

The critical two-terminal conductance $g_c$ and the spatial fluctuations of critical eigenstates are investigated for a disordered two dimensional model of non-interacting electrons subject to spin-orbit scattering (Ando model). For square samples, we verify numerically the relation $\sigma_c=1/[2\pi(2-D(1))] e^2/h$ between critical conductivity $\sigma_c=g_c=(1.42\pm 0.005) e^2/h$ and the fractal information dimension of the electron wave function, $D(1)=1.889\pm 0.001$. Through a detailed numerical scaling analysis of the two-terminal conductance we also estimate the critical exponent $\nu=2.80\pm 0.04$ that governs the quantum phase transition.Comment: IOP Latex, 7 figure

Noncommutative deformation of four dimensional Einstein gravity

We construct a model for noncommutative gravity in four dimensions, which reduces to the Einstein-Hilbert action in the commutative limit. Our proposal is based on a gauge formulation of gravity with constraints. While the action is metric independent, the constraints insure that it is not topological. We find that the choice of the gauge group and of the constraints are crucial to recover a correct deformation of standard gravity. Using the Seiberg-Witten map the whole theory is described in terms of the vierbeins and of the Lorentz transformations of its commutative counterpart. We solve explicitly the constraints and exhibit the first order noncommutative corrections to the Einstein-Hilbert action.Comment: LaTex, 11 pages, comments added, to appear in Classical and Quantum Gravit

Substratos e temperaturas para a germinação de sementes de magnólia-amarela (Michelia champaca Linn).

O trabalho objetiva determinar os melhores substratos e temperaturas para a germinação de sementes de magnolia-amarela.bitstream/item/96211/1/CPAF-AP-2000-Substratos-Magnolia.pd

A Very Low Resource Language Speech Corpus for Computational Language Documentation Experiments

Most speech and language technologies are trained with massive amounts of speech and text information. However, most of the world languages do not have such resources or stable orthography. Systems constructed under these almost zero resource conditions are not only promising for speech technology but also for computational language documentation. The goal of computational language documentation is to help field linguists to (semi-)automatically analyze and annotate audio recordings of endangered and unwritten languages. Example tasks are automatic phoneme discovery or lexicon discovery from the speech signal. This paper presents a speech corpus collected during a realistic language documentation process. It is made up of 5k speech utterances in Mboshi (Bantu C25) aligned to French text translations. Speech transcriptions are also made available: they correspond to a non-standard graphemic form close to the language phonology. We present how the data was collected, cleaned and processed and we illustrate its use through a zero-resource task: spoken term discovery. The dataset is made available to the community for reproducible computational language documentation experiments and their evaluation.Comment: accepted to LREC 201

Conservação de sementes de pinheiro-do-paraná sob diferentes condições de ambientes e embalagens.

bitstream/CNPF-2009-09/16620/1/com_tec34.pd

Colheita antecipada de frutos e tratamentos pré-germinativos para a germinação de sementes de mandiocão (Didymopanx morototoni (Aublet) Ecaisne et Planchon).

O trabalho objetiva, através da condução de um experimento, verificar a viabilidade de sementes obtidas de colheita antecipada de infrutencias, em um estadio anterior a mudança de coloração dos frutos de verde para violeta, diminuindo com isto a competição dos animais, e pelas mesmas apresentarem baixa porcentagem inicial de germinação.bitstream/item/96213/1/CPAF-AP-2000-Colheita-Mandiocao.pd

Substratos e temperaturas para a germinação de sementes de Alnus subcordata C. A. Mey.

O trabalho visa determinar condições ótimas para o teste de germinação das sementes de Alnus subcordata C. A. Mey.bitstream/item/96212/1/CPAF-AP-2000-Substratos-Germinacao.pd