462 research outputs found
Levantamento fitossociolĂłgico em Floresta OmbrĂłfila Densa Submontana, MunicĂpio de Guaraqueçaba, localidade de Serra Negra, Paraná.
1 CD-ROM. Autoria bilĂngue: CONGRESSO E EXPOSICAO INTERNACIONAL SOBRE FLORESTAS, 5., 1999, Curitiba
Stationary Metrics and Optical Zermelo-Randers-Finsler Geometry
We consider a triality between the Zermelo navigation problem, the geodesic
flow on a Finslerian geometry of Randers type, and spacetimes in one dimension
higher admitting a timelike conformal Killing vector field. From the latter
viewpoint, the data of the Zermelo problem are encoded in a (conformally)
Painleve-Gullstrand form of the spacetime metric, whereas the data of the
Randers problem are encoded in a stationary generalisation of the usual optical
metric. We discuss how the spacetime viewpoint gives a simple and physical
perspective on various issues, including how Finsler geometries with constant
flag curvature always map to conformally flat spacetimes and that the Finsler
condition maps to either a causality condition or it breaks down at an
ergo-surface in the spacetime picture. The gauge equivalence in this network of
relations is considered as well as the connection to analogue models and the
viewpoint of magnetic flows. We provide a variety of examples.Comment: 37 pages, 6 figure
Kaluza-Klein Consistency, Killing Vectors, and Kahler Spaces
We make a detailed investigation of all spaces Q_{n_1... n_N}^{q_1... q_N} of
the form of U(1) bundles over arbitrary products \prod_i CP^{n_i} of complex
projective spaces, with arbitrary winding numbers q_i over each factor in the
base. Special cases, including Q_{11}^{11} (sometimes known as T^{11}),
Q_{111}^{111} and Q_{21}^{32}, are relevant for compactifications of type IIB
and D=11 supergravity. Remarkable ``conspiracies'' allow consistent
Kaluza-Klein S^5, S^4 and S^7 sphere reductions of these theories that retain
all the Yang-Mills fields of the isometry group in a massless truncation. We
prove that such conspiracies do not occur for the reductions on the Q_{n_1...
n_N}^{q_1... q_N} spaces, and that it is inconsistent to make a massless
truncation in which the non-abelian SU(n_i+1) factors in their isometry groups
are retained. In the course of proving this we derive many properties of the
spaces Q_{n_1... n_N}^{q_1... q_N} of more general utility. In particular, we
show that they always admit Einstein metrics, and that the spaces where
q_i=(n_i+1)/\ell all admit two Killing spinors. We also obtain an iterative
construction for real metrics on CP^n, and construct the Killing vectors on
Q_{n_1... n_N}^{q_1... q_N} in terms of scalar eigenfunctions on CP^{n_i}. We
derive bounds that allow us to prove that certain Killing-vector identities on
spheres, necessary for consistent Kaluza-Klein reductions, are never satisfied
on Q_{n_1... n_N}^{q_1... q_N}.Comment: Latex, 43 pages, references added and typos correcte
Potencial de aproveitamento medicinal de especies do sub-bosque dos bracatingais da regiao de Curitiba, PR.
Principais especies do sub-bosque dos bracatingais; Area ocupada pelos bracatingais; Perfil quimico e farmacologico das principais familias encontradas nos bracatingais; Abordagem fitoquimica das especies de maior densidade nos estudos fitossociologicos; Levantamento sobre uso popular de plantas, conhecimentos sobre plantas medicinais e seus usos, plantas medicinais nativas mais usadas pela populacao local, plantas utilizadas no combate a doencas de animais, plantas toxicas identificadas por moradores da regiao; Aspectos de mercado, demanda de plantas medicinais, importacao e exportacao de plantas medicinais, abastecimento local e regional de plantas medicinais.bitstream/item/17053/1/doc43.pd
Chances and Limitations of Wild Bird Monitoring for the Avian Influenza Virus H5N1 — Detection of Pathogens Highly Mobile in Time and Space
Highly pathogenic influenza virus (HPAIV) H5N1 proved to be remarkably mobile in migratory bird populations where it has led to extensive outbreaks for which the true number of affected birds usually cannot be determined. For the evaluation of avian influenza monitoring and HPAIV early warning systems, we propose a time-series analysis that includes the estimation of confidence intervals for (i) the prevalence in outbreak situations or (ii) in the apparent absence of disease in time intervals for specified regional units. For the German outbreak regions in 2006 and 2007, the upper 95% confidence limit allowed the detection of prevalences below 1% only for certain time intervals. Although more than 25,000 birds were sampled in Germany per year, the upper 95% confidence limit did not fall below 5% in the outbreak regions for most of the time. The proposed analysis can be used to monitor water bodies and high risk areas, also as part of an early-warning system. Chances for an improved targeting of the monitoring system as part of a risk-based approach are discussed with the perspective of reducing sample sizes
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