Fenologia reprodutiva de espécies vegetais da Floresta Ombrófila Mista do Paraná, Brasil.

(Reproductive phenology of plant species of Mixed Ombrophilous Forest in Paraná, Brazil). The Mixed Ombrophilous Forest (FOM) or Araucaria Forest, vegetation that occupies regions with a highly seasonal climate subject to frost, used to cover 40% of Paraná State. Nowadays, however, there is less than 1% of advanced and well conserved FOM covering this State. This study presents the reproductive phenological patterns (flowering and fruiting) of the plant species found in FOM fragments located in three municipalities of Paraná State in order to subside restoration activities. Monthly phenological observations in 543 individuals of 145 species, representing several life forms (71 trees, 52 bushes, 18 vines and four epiphytes) were conducted between January 2004 and December 2005 employing the activity index. Flowering was recorded mainly between September and December, with a peak in October and November (68 species), followed by fruiting, which was concentrated between December and April, peaking in February (61 species). During the coldest months (June to August), the number of species with flowers or fruits was very low, with less than five species per phenophase. The availability of araucaria (Araucaria angustifolia (Bertol.) Kuntze) seeds varied between the years, but usually occurred between April and September. Significant correlations between phenophases and some abiotic factors, especially day length and temperature, were found. Therefore, plant species of the FOM proved to be highly seasonal, with periods of high and low flowering and fruiting activity, as consequence of the climatic seasonality, characteristic of the study region

Doping-driven Mott transition in La_{1-x}Sr_xTiO_3 via simultaneous electron and hole doping of t2g subbands

The insulator to metal transition in LaTiO_3 induced by La substitution via Sr is studied within multi-band exact diagonalization dynamical mean field theory at finite temperatures. It is shown that weak hole doping triggers a large interorbital charge transfer, with simultaneous electron and hole doping of t2g subbands. The transition is first-order and exhibits phase separation between insulator and metal. In the metallic phase, subband compressibilities become very large and have opposite signs. Electron doping gives rise to an interorbital charge flow in the same direction as hole doping. These results can be understood in terms of a strong orbital depolarization.Comment: 4 pages, 5 figure

Danos provocados por macaco-prego em povoamentos de pinus spp.

Editores técnicos: Marcílio José Thomazini, Elenice Fritzsons, Patrícia Raquel Silva, Guilherme Schnell e Schuhli, Denise Jeton Cardoso, Luziane Franciscon. EVINCI. Resumos

Photoemission Beyond the Sudden Approximation

The many-body theory of photoemission in solids is reviewed with emphasis on methods based on response theory. The classification of diagrams into loss and no-loss diagrams is discussed and related to Keldysh path-ordering book-keeping. Some new results on energy losses in valence-electron photoemission from free-electron-like metal surfaces are presented. A way to group diagrams is presented in which spectral intensities acquire a Golden-Rule-like form which guarantees positiveness. This way of regrouping should be useful also in other problems involving spectral intensities, such as the problem of improving the one-electron spectral function away from the quasiparticle peak.Comment: 18 pages, 11 figure

Danos provicados por Cebus nigritus (Goldfuss, 1809) a plantios de Pinus taeda L: frequência e perdas de incremento.

Resumo

Levantamento florístico e síndromes de dispersão em remanescentes de Floresta Ombrófila Mista na região centro-sul do estado do Paraná.

(Floristic survey and dispersal syndromes in Araucaria Forest remnants of Parana state, Brazil). This study presents a list of plants found in three areas of Araucaria Forest along with their dispersal syndromes. We sampled monthly (August 2003 to December 2005) fi ve transects with 5 km each, collecting samples of fl owering and fruiting plants. We identifi ed 210 species, including 83 trees, 58 shrubs, 36 herbs, 23 vines, eight epiphytes and two parasites. Most species were zoochorous (68.6%), followed by anemochorous (21.9%) and autochorous (6.7%) ones. Comparisons with other fl orist surveys previously conducted in this forest type suggested that our study areas are poor, both when all species are taken into account or when just trees are. The results are discussed based on the history of degradation of the study region and on the abundance of bamboos in the understory

Electron rescattering at metal nanotips induced by ultrashort laser pulses

We report on the first investigation of plateau and cut-off structures in photoelectron spectra from nano-scale metal tips interacting with few-cycle near-infrared laser pulses. These hallmarks of electron rescattering, well-known from atom-laser interaction in the strong-field regime, appear at remarkably low laser intensities with nominal Keldysh parameters of the order of $\gtrsim 10$. Quantum and quasi-classical simulations reveal that a large field enhancement near the tip and the increased backscattering probability at a solid-state target play a key role. Plateau electrons are by an order of magnitude more abundant than in comparable atomic spectra, reflecting the high density of target atoms at the surface. The position of the cut-off serves as an in-situ probe for the locally enhanced electric field at the tip apex