Photonuclear reactions of actinides in the giant dipole resonance region

Photonuclear reactions at energies covering the giant dipole resonance (GDR) region are analyzed with an approach based on nuclear photoabsorption followed by the process of competition between light particle evaporation and fission for the excited nucleus. The photoabsorption cross section at energies covering the GDR region is contributed by both the Lorentz type GDR cross section and the quasideuteron cross section. The evaporation-fission process of the compound nucleus is simulated in a Monte-Carlo framework. Photofission reaction cross sections are analyzed in a systematic manner in the energy range of $\sim$ 10-20 MeV for the actinides $^{232}$Th, $^{238}$U and $^{237}$Np. Photonuclear cross sections for the medium-mass nuclei $^{63}$Cu and $^{64}$Zn, for which there are no fission events, are also presented. The study reproduces satisfactorily the available experimental data of photofission cross sections at GDR energy region and the increasing trend of nuclear fissility with the fissility parameter $Z^2/A$ for the actinides.Comment: 4 pages including 2 tables and 1 figur

Superluminal Localized Solutions to Maxwell Equations propagating along a waveguide: The finite-energy case

In a previous paper of ours [Phys. Rev. E64 (2001) 066603, e-print physics/0001039] we have shown localized (non-evanescent) solutions to Maxwell equations to exist, which propagate without distortion with Superluminal speed along normal-sized waveguides, and consist in trains of "X-shaped" beams. Those solutions possessed therefore infinite energy. In this note we show how to obtain, by contrast, finite-energy solutions, with the same localization and Superluminality properties. [PACS nos.: 41.20.Jb; 03.50.De; 03.30.+p; 84.40.Az; 42.82.Et. Keywords: Wave-guides; Localized solutions to Maxwell equations; Superluminal waves; Bessel beams; Limited-dispersion beams; Finite-energy waves; Electromagnetic wavelets; X-shaped waves; Evanescent waves; Electromagnetism; Microwaves; Optics; Special relativity; Localized acoustic waves; Seismic waves; Mechanical waves; Elastic waves; Guided gravitational waves.]Comment: plain LaTeX file (12 pages), plus 10 figure

Primakoff effect in eta-photoproduction off protons

We analyse data on forward eta-meson photoproduction off a proton target and extract the eta to gamma gamma decay width utilizing the Primakoff effect. The hadronic amplitude that enters into our analysis is strongly constrained because it is fixed from a global fit to available gamma p to p eta data for differential cross sections and polarizations. We compare our results with present information on the two-photon eta-decay from the literature. We provide predictions for future PrimEx experiments at Jefferson Laboratory in order to motivate further studies.Comment: 5 pages, 6 figures, gamma-gamma*-eta form factor included, version to appear in Eur. Phys. J. A

Vascular Flora Of The Legado Das Águas, Reserva Votorantim, Municipalities Of Tapiraí, Miracatú And Juquiá, São Paulo, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)We present a list of vascular plants found in Legado das Águas, Reserva Votorantim, a private reserve having an area of approximately 35,000 ha that spans the municipalities of Tapiraí, Miracatú, and Juquiá, in the state of São Paulo, Brazil. The reserve is part of a complex of state-protected areas including Alto Ribeira Touristic State Park, Intervales State Park, Carlos Botelho State Park, Jurupará State Park, and Serra do Mar State Park. Together, these form an important and large area of continuous and well-preserved forest. Our study, which involved two main floristic surveys in March/April 2013 and April 2014, recorded 768 species, representing 131 families and 432 genera. The majority of species were angiosperms (619) representing 106 families and 370 genera. There were also two species of gymnosperms belonging to two genera in separate families; 147 species of ferns and lycophytes belonging to 23 families and 60 genera. In demonstrating the presence of almost 800 species of plants, of which 16 are threatened, our study highlights the importance of floristic surveys and the critical role of private protected areas in managing and preserving native flora. © 2016 Check List and Authors.1262011/22923-8, FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo2015/9444-4, FAPESP, Fundação de Amparo à Pesquisa do Estado de São PauloFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Estudos sobre a nutrição mineral do arroz: XIV. efeitos dos excessos de Al, Cl e Mn nas variedades IAC-25 e IAC-47

Rice plants were grown either in full strength nº 2 solution of HOAGLAND & ARNON (1950) or in the same with high levels of Al, Cl and Mn (25, 1750 and 25 ppm, respectively). Plants with excess of each element did not complete the reproductive phase of development. Symptoms of toxicity appeared in response to the high levels supplied in the substrate. Dry matter production was relatively more affected in the case of the variety IAC-47. On the other hand, both varieties were more sensitive to Mn toxicity than to Al excess. The leaves had the following levels of the elements under the respective treatments, respectively for the variety IAC-25 and for the variety IAC-47; Al-107 and 221 ppm; Cl-87,500 and 17,500 (lower and upper leaves), 44,125 and 16,250 (lower and upper leaves); Mn - 1,670 and 1,769. The Al content of the roots was 5,639 and 5,872 ppm. Al toxicity decreased P content in all plant parts.Plantas de arroz, variedades IAC-25 e IAC-47 foram cultivadas em solução nutritiva completa e com excesso de Al, Cl e Mn (25, 1750 e 25 ppm, respectivamente). As últimas não completaram o ciclo. Foram observados sintomas típicos de toxidez. A produção de matéria seca foi mais afetada pelos tratamentos na variedade IAC-47. Ambas as variedades mostraram-se mais sensíveis a toxidez de Mn que à de Al. Foram determinados os teores foliares de Al, Cl e Mn associados à toxidez correspondente

Studies on the mineral nutrition of the rice plant: IX. time course on the uptake of macronutrients by the variety IAC-47

Rice plants, variety IAC-47, were grown in the nº 2 nutrient solution of HOAGLAND & ARNON (1950) until the end of the life cycle. Plants were sampled at well defined physiological periods for analyses. It was verified that trends for levvelling off occurred in the case of accumulation of N, K and Ca. Translocation from leaves to grain was observed with respect to N, P and K. Maximum rates of uptake of all elements took place from 50 to 100 days after germination.Foram estudadas, em condições controladas, a acumulação de matéria seca e a de macronutrientes na variedade de arroz IAC-47. Ambos os processos em geral são descritos por sigmóides típicas; picos para os valores totais de produção de matéria seca e de acumulação de elementos entre: 100 e 140 dias depois da germinação

Estudos sobre a nutrição mineral do arroz: VII. exigências nutricionais das variedades IAC-25 e IAC-47

Rice plants, varieties IAC 25 and IAC 47, were grown in nutrient solution till the end of the life cycle when they were analysed both for macro and micronutrients. Main conclusions were the following: IAC 47, higher yielding, showed larger requirements than IAC 25; for production (total) and export (grain), the demand for nutrients was the same in both varieties.As exigências nutricionais das variedades de arroz IAC 25 e IAC 47 foram determinadas analisando-se os diferentes órgãos de plantas cultivadas em solução nutritiva até o fim do ciclo. Verificou-se serem distintas as exigências, maior na IAC 47 (mais tardia) que deu também maior produção de grãos com casca

Estudos sobre a nutrição mineral do arroz: XIII. efeitos das deficiências de micronutrientes nas variedades IAC-25 e IAC-47

Rice plants were grown in nutrient solution lither in the presence or in the absence of B, Cu and Zn. The symptoms of deficiency were usually in agreement with those described in the literature. Growth of the variety IAC-47 (number of leaves, tillering and total dry matter) was relatively more affected; this variety, however did produce grains under the minus Cu treatment (one fourth of the yield observed in the "complete" treatment), which did not happen in the case of the other variety. At the beginning of the grain filling period the following leaf contents could be considered as indication of deficiency: B-13 to 25 ppm; Zn-20 ppm; no conclusion could be drawn with respect to Cu levels.Plantas de arroz, variedades IAC-25 e IAC-47 foram cultivadas em solução nutritiva e com deficiência de B, Cu e Zn. Foram obtidos sintomas de carência dos três micronutrientes. As deficiências induzidas provocaram diminuição na matéria seca total e no número de folhas das duas variedades. O mesmo ocorreu no numero de perfilhos da var. IAC-47. Foi feita a determinação dos teores dos micronutrientes nas plantas submetidas aos diferentes tratamentos o que forneceu dados que ajudam a avaliação do estado nutricional