Agricultura familiar no Estado da Paraíba: uma análise a partir de tabulações especiais do Censo Agropecuário 2006.

Este artigo objetiva analisar a importância socioeconômica e as desigualdades que caracterizam a agricultura familiar no estado da Paraíba. Para tanto, utiliza dados de ?tabulações especiais? do Censo Agropecuário 2006, elaboradas segundo o recorte da Lei da Agricultura Familiar e das normas do Plano Safra da Agricultura Familiar 2006/2007. O trabalho mostra que a agricultura familiar é o segmento social mais relevante no rural paraibano. Todavia, há uma grande heterogeneidade e desigualdade social no interior dessa categoria de produtores, onde a maioria são extremamente pobres e apenas uma pequena parcela consegue sobreviver a partir das atividades agropecuárias. Essa constatação revela o risco de considerar a agricultura familiar como um setor homogêneo e, ao mesmo tempo, abre novas possibilidades de pesquisa que podem ampliar o campo de ação das políticas públicas de desenvolvimento rural

Agricultura familiar no Estado da Paraíba: uma análise a partir de tabulações especiais do censo agropecuário 2006.

O objetivo deste artigo é demonstrar o peso socioeconômico da agricultura familiar paraibana com base em ?tabulações especiais? do Censo Agropecuário 2006, apresentando os principais segmentos que se destacam no interior dessa categoria de produtores e a composição da renda. As ?tabulações especiais? foram elaboradas segundo o recorte da Lei da Agricultura Familiar e a partir das normas do PRONAF vigentes no Plano Safra 2006/2007. O trabalho mostra que a agricultura familiar é o segmento social predominante no rural paraibano. Todavia, há uma grande heterogeneidade e desigualdade social no interior dessa categoria de produtores, onde a maioria são extremamente pobres e apenas uma pequena parcela consegue sobreviver a partir das atividades agropecuárias. Essa constatação revela o risco de considerar a agricultura familiar como um setor homogêneo e, ao mesmo tempo, abre novas possibilidades de pesquisa que podem ampliar o campo de ação das políticas públicas de desenvolvimento rural

Universally diverging Grueneisen parameter and the magnetocaloric effect close to quantum critical points

At a generic quantum critical point, the thermal expansion $\alpha$ is more singular than the specific heat $c_p$. Consequently, the "Gr\"uneisen ratio'', \GE=\alpha/c_p, diverges. When scaling applies, \GE \sim T^{-1/(\nu z)} at the critical pressure $p=p_c$, providing a means to measure the scaling dimension of the most relevant operator that pressure couples to; in the alternative limit $T\to0$ and $p \ne p_c$, \GE \sim \frac{1}{p-p_c} with a prefactor that is, up to the molar volume, a simple {\it universal} combination of critical exponents. For a magnetic-field driven transition, similar relations hold for the magnetocaloric effect $(1/T)\partial T/\partial H|_S$. Finally, we determine the corrections to scaling in a class of metallic quantum critical points.Comment: 4 pages, 1 figure; general discussion on how the Grueneisen exponent measures the scaling dimension of the most relevant operator at any QCP is expande

The spatially resolved star formation history of CALIFA galaxies: Cosmic time scales

This paper presents the mass assembly time scales of nearby galaxies observed by CALIFA at the 3.5m telescope in Calar Alto. We apply the fossil record method of the stellar populations to the complete sample of the 3rd CALIFA data release, with a total of 661 galaxies, covering stellar masses from 10$^{8.4}$ to 10$^{12}$ M$_{\odot}$ and a wide range of Hubble types. We apply spectral synthesis techniques to the datacubes and process the results to produce the mass growth time scales and mass weighted ages, from which we obtain temporal and spatially resolved information in seven bins of galaxy morphology and six bins of stellar mass (M$_{\star}$) and stellar mass surface density ($\Sigma_{\star}$). We use three different tracers of the spatially resolved star formation history (mass assembly curves, ratio of half mass to half light radii, and mass-weighted age gradients) to test if galaxies grow inside-out, and its dependence with galaxy stellar mass, $\Sigma_{\star}$, and morphology. Our main results are as follows: (a) The innermost regions of galaxies assemble their mass at an earlier time than regions located in the outer parts; this happens at any given M$_{\star}$, $\Sigma_{\star}$, or Hubble type, including the lowest mass systems. (b) Galaxies present a significant diversity in their characteristic formation epochs for lower-mass systems. This diversity shows a strong dependence of the mass assembly time scales on $\Sigma_{\star}$ and Hubble type in the lower-mass range (10$^{8.4}$ to 10$^{10.4}$), but a very mild dependence in higher-mass bins. (c) All galaxies show negative $\langle$log age$\rangle_{M}$ gradients in the inner 1 HLR. The profile flattens with increasing values of $\Sigma_{\star}$. There is no significant dependence on M$_{\star}$ within a particular $\Sigma_{\star}$ bin, except for the lowest bin, where the gradients becomes steeper.Comment: 15 pages, 13 figures, 3 tables, accepted for publication in Astronomy & Astrophysics. *Abridged abstract

The spatially-resolved star formation histories of CALIFA galaxies: Implications for galaxy formation

This paper presents the spatially resolved star formation history (SFH) of nearby galaxies with the aim of furthering our understanding of the different processes involved in the formation and evolution of galaxies. To this end, we apply the fossil record method of stellar population synthesis to a rich and diverse data set of 436 galaxies observed with integral field spectroscopy in the CALIFA survey. The sample covers a wide range of Hubble types, with stellar masses ranging from $M_\star \sim 10^9$ to $7 \times 10^{11} M_\odot$. Spectral synthesis techniques are applied to the datacubes to retrieve the spatially resolved time evolution of the star formation rate (SFR), its intensity ($\Sigma_{\rm SFR}$), and other descriptors of the 2D-SFH in seven bins of galaxy morphology (E, S0, Sa, Sb, Sbc, Sc, and Sd), and five bins of stellar mass. Our main results are: a) Galaxies form very fast independently of their current stellar mass, with the peak of star formation at high redshift ($z > 2$). Subsequent star formation is driven by $M_\star$ and morphology, with less massive and later type spirals showing more prolonged periods of star formation. b) At any epoch in the past the SFR is proportional to $M_\star$, with most massive galaxies having the highest absolute (but lowest specific) SFRs. c) While nowadays $\Sigma_{\rm SFR}$ is similar for all spirals, and significantly lower in early type galaxies (ETG), in the past $\Sigma_{\rm SFR}$ scales well with morphology. The central regions of today's ETGs are where $\Sigma_{\rm SFR}$ reached the highest values ($> 10^3 \,M_\odot\,$Gyr$^{-1}\,$pc$^{-2}$), similar to those measured in high redshift star forming galaxies. d) The evolution of $\Sigma_{\rm SFR}$ in Sbc systems matches that of models for Milky-Way-like galaxies, suggesting that the formation of a thick disk may be a common phase in spirals at early epochs.Comment: 21 pages, 11 figures, 1 table, accepted for publication in Astronomy & Astrophysics, abstract abridged for arXiv submissio

Influence of spacing regimes on the development of loblolly pine (Pinus taeda L.) in southern Brazil.

Edição dos abstracts do 24º IUFRO World Congress, 2014, Salt Lake City. Sustaining forests, sustaining people: the role of research

Influência de regimes de espaçamento e desbaste na produção em volume de Pinus taeda L. ao final da rotação no nordeste do Paraná.

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