On the long-term correlation between the flux in the Ca II H & K and Halpha lines for FGK stars

The re-emission in the cores of the Ca II H & K and H$\alpha$ lines, are well known proxies of stellar activity. However, these activity indices probe different activity phenomena, the first being more sensitive to plage variation, while the other one being more sensitive to filaments. In this paper we study the long-term correlation between $\log R'_{HK}$ and $\log I_{H\alpha}$, two indices based on the Ca II H & K and H$\alpha$ lines respectively, for a sample of 271 FGK stars using measurements obtained over a $\sim$9 year time span. Because stellar activity is one of the main obstacles to the detection of low-mass and long-period planets, understanding further this activity index correlation can give us some hints about the optimal target to focus on, and ways to correct for these activity effects. We found a great variety of long-term correlations between $\log R'_{HK}$ and $\log I_{H\alpha}$. Around 20% of our sample has strong positive correlation between the indices while about 3% show strong negative correlation. These fractions are compatible with those found for the case of early-M dwarfs. Stars exhibiting a positive correlation have a tendency to be more active when compared to the median of the sample, while stars showing a negative correlation are more present among higher metallicity stars. There is also a tendency for the positively correlated stars to be more present among the coolest stars, a result which is probably due to the activity level effect on the correlation. Activity level and metallicity seem therefore to be playing a role on the correlation between $\log R'_{HK}$ and $\log I_{H\alpha}$. Possible explanations based on the influence of filaments for the diversity in the correlations between these indices are discussed in this paper.Comment: 18 pages, 13 figures, 4 tables, accepted for publication in Astronomy and Astrophysic

Algebroid Yang-Mills Theories

A framework for constructing new kinds of gauge theories is suggested. Essentially it consists in replacing Lie algebras by Lie or Courant algebroids. Besides presenting novel topological theories defined in arbitrary spacetime dimensions, we show that equipping Lie algebroids E with a fiber metric having sufficiently many E-Killing vectors leads to an astonishingly mild deformation of ordinary Yang-Mills theories: Additional fields turn out to carry no propagating modes. Instead they serve as moduli parameters gluing together in part different Yang-Mills theories. This leads to a symmetry enhancement at critical points of these fields, as is also typical for String effective field theories.Comment: 4 pages; v3: Minor rewording of v1, version to appear in Phys. Rev. Let

Heranca da tolerancia de melancia aos virus do mosaico amarelo da abobrinha-de-moita e do mosaico da melancia-2.

A heranca da tolerancia da introducao de melancia BT-8501 aos virus do mosaico amarelo da abobrinha-de-moita (ZYMV) e do mosaico da melancia-2 (WMV-2) foi determinada atraves da inoculacao mecanica de plantas das geracoes parentais, F1, F2 e retrocruzamento para os progenitores "Perola" (sensivel) e BT-8501 (tolerante). A heranca da tolerancia de BT-8501 ao ZYMV e WMV-2, confirmada com testes de progenies, demonstrou ser devida a dois pares de genes recessivos com modificadores tambem recessivos, que parecem controlar a tolerancia a ambas as viroses

Modified poly(heptazine imides) : minimizing H₂O₂ decomposition to maximize oxygen reduction

Photocatalysis provides a sustainable pathway to produce the consumer chemical H2O2 from atmospheric O2 via an oxygen reduction reaction (ORR). Such an alternative is attractive to replace the cumbersome traditional anthraquinone method for H2O2 synthesis on a large scale. Carbon nitrides have shown very interesting results as heterogeneous photocatalysts in ORR because their covalent two-dimensional (2D) structure is believed to increase selectivity toward the two-electron process. However, an efficient and scalable application of carbon nitrides for this reaction is far from being achieved. Poly(heptazine imides) (PHIs) are a more powerful subgroup of carbon nitrides whose structure provides high crystallinity and a scaffold to host transition-metal single atoms. Herein, we show that PHIs functionalized with sodium and the recently reported fully protonated PHI exhibit high activity in two-electron ORR under visible light. The latter converted O2 to up to 1556 mmol L–1 h–1 g–1 H2O2 under 410 nm irradiation using inexpensive but otherwise chemically demanding glycerin as a sacrificial electron donor. We also prove that functionalization with transition metals is not beneficial for H2O2 synthesis, as the metal also catalyzes its decomposition. Transient photoluminescence spectroscopy suggests that H-PHIs exhibit higher activity due to their longer excited-state lifetime. Overall, this work highlights the high photocatalytic activity of the rarely examined fully protonated PHI and represents a step forward in the application of inexpensive covalent materials for photocatalytic H2O2 synthesis

Desempenho de laranjeiras em Capitão Poço, PA.

O estudo teve como objetivo avaliar o comportamento de 13 variedades de laranjeiras (Citrus sinensis (L.) osbeck) nas condições edafoclimáticas de Capitão Poço, PA, a fim de selecionar aquelas superiores para caracteres de interesse agronômico e econômico. O trabalho foi desenvolvido em solo tipo Latossolo Amarelo distrófico, clima tipo Ami da classificação de Köppen, sendo avaliadas as variedades de laranjeiras, PêraD6; Sunstar; Pinneaple; Parson Brown; Westin; Gardner; BaianinhaIAC79; Valênciacnpmf27; Natalcnpmf112; Salustiana; Rubi; Midsweet; e Seleta. Os dados foram coletados em plantas com 4 anos de idade, sendo estes: produção de frutos por planta e por safra; peso do fruto e do suco; espessura da casca e diâmetros transversal; e longitudinal do fruto. Do suco, determinaram-se a acidez total titulável, sólidos solúveis totais, pH e relação sólidos solúveis totais/acidez total titulável. Detectaram-se diferenças significativas (p<0,05) para produção de frutos e espessura de casca, e altamente significativas (p<0,01) para peso do fruto e do suco e diâmetros transversal e longitudinal. Os resultados demonstraram que as cultivares se adaptaram bem às condições edafoclimáticas da região produtora de Capitão Poço, e que é possível produzir, na região, frutos que possam ser destinados a indústrias processadoras de suco concentrado e congelado, e que as laranjeiras Westin, BaianinhaICA 79, Pinneaple e Rubi poderão compor os sistemas de produção, cujo destino seja produzir frutos para o mercado de consumo "in natura".bitstream/item/37708/1/ORIENTAL-BPD57.pdfVersão eletrônica. 1ª impressão: 2009

Traceability for Model Driven, Software Product Line Engineering

Traceability is an important challenge for software organizations. This is true for traditional software development and even more so in new approaches that introduce more variety of artefacts such as Model Driven development or Software Product Lines. In this paper we look at some aspect of the interaction of Traceability, Model Driven development and Software Product Line

Estudos de Solos do Município de Aceguá, RS

bitstream/item/130155/1/Circular-157.pd

Phosphorus efficiency in brazilian soybean cultivars.

The primary goal of this study was to evaluate the phosphorus uptake and use efficiency in Brazilian soybean cultivars, besides root morphology and architecture characteristics related to phosphorus uptake, carrying out two greenhouse experiments. The experiment 1 was completely randomised, with 56 treatments (soybean cultivars) and 3 replicates. Experiment 2 was completely randomised design with three replicates, and the ten cultivars (greater and lower efficiency) were selected for this assay according to their ability to absorb phosphorus less available determined in experiment 1. The study was carried out at Center of Nuclear Energy in Agriculture, University of São Paulo, Brazil, between February 2011 and August 2012. The isotopic dilution technique was used in the first experiment to assess the phosphorus availability in the soil and to determine the ability of plants to access labile phosphorus by measuring the specific activity of plants grown in soil labeled with radioactive phosphorus. Nine cultivars showed greater phosphorus uptake and used efficiency. The second experiment evaluated the root morphology and architecture. The cultivars with greater uptake efficiency have root morphology and architecture characteristics that favour acquisition of phosphorus from soil compartments that are inaccessible to other cultivars. Phosphorus uptake by plants was not affected by soybean seeds phosphorus content. Identification of these cultivars is very important because it could enable soybean farming in low fertility soils, reducing fertiliser dependence