A sustentabilidade das reservas extrativistas pela perspectiva da economia ecológica.

As Reservas Extrativistas (RESEX) são áreas de domínio público, com uso concedido às populações extrativistas tradicionais, cuja subsistência baseia-se no extrativismo e na agricultura de subsistência e na criação de animais de pequeno porte, e têm como objetivos básicos proteger os meios de vida e a cultura dessas populações, e assegurar o uso sustentável dos recursos naturais da unidade. Porém, o aumento da área para agropecuária dentro das reservas vem aumentando e, assim, o desmatamento. O presente estudo tem como objetivo promover uma reflexão sobre a regulamentação ambiental. A parte metodológica deste trabalho é baseada na literatura sobre o tema dentro do contexto da Economia Ecológica. Assim, este trabalho procura analisar a eficácia da regulamentação ambiental no sentido de deter os desmatamentos e garantir a manutenção das reservas extrativistas. Centrou-se a atenção nos instrumentos reguladores de comando e controle (C&C) e no uso de instrumentos econômicos (IE). As principais conclusões indicam que, apesar dos desafios, a pertinência e acerto da política ambiental representados pela existência das RESEX são evidentes. No plano real trata-se da melhor e mais adequada proposta de conservação da floresta amazônica. Contribuiu em muito para o êxito da proposta a ampla mobilização do conjunto de moradores da reserva. A adoção de um mix de políticas ambientais, envolvendo políticas de comando e controle e uso de instrumentos econômicos legitima e assegura a efetivação das medidas. Em decorrência, os controles e a fiscalização, em geral dispendiosos, tornam-se viáveis em função do envolvimento dos moradores

Sulfur, Chlorine, & Argon Abundances in Planetary Nebulae. I: Observations and Abundances in a Northern Sample

This paper is the first of a series specifically studying the abundances of sulfur, chlorine, and argon in Type II planetary nebulae (PNe) in the Galactic disk. Ratios of S/O, Cl/O, and Ar/O constitute important tests of differential nucleosynthesis of these elements and serve as strict constraints on massive star yield predictions. We present new ground-based optical spectra extending from 3600-9600 Angstroms for a sample of 19 Type II northern PNe. This range includes the strong near infrared lines of [S III] 9069,9532, which allows us to test extensively their effectiveness as sulfur abundance indicators. We also introduce a new, model-tested ionization correction factor for sulfur. For the present sample, we find average values of S/O=1.2E-2(+/- 0.71E-2), Cl/O=3.3E-4(+/- 1.6E-4), and Ar/O=5.0E-3(+/- 1.9E-3).Comment: 44 pages, 6 figures. Accepted for publication in the Astrophysical Journa

Seleção assistida com uso de marcador molecular para resistência a potyvírus em pimentão.

O objetivo deste trabalho foi determinar a presença do alelo Pvr4, que confere resistência contra o PepYMV (Pepper yellow mosaic virus), em genótipos de pimentão comunmente encontrados no mercado brasileiro, com uso de um marcador molecular codominante tipo CAPS. A resistência ao PepYMV, nos genótipos CM?334?INRA, Myr?29 e em genótipos derivados do híbrido comercial Mônica?R, foi detectada como associada à banda de 444 pb, ligada ao alelo de resistência Pvr4. As plantas resistentes homozigotas (pvr4/pvr4) mostraram uma banda de 444 pb, as suscetíveis (Pvr4+/Pvr4+) uma banda de 458 pb e as resistentes heterozigotas (Pvr4+/Pvr4) mostraram as duas bandas. No entanto, no acesso resistente CM?334?UFV, nos híbridos Magali?R e Martha?R, assim como em populações derivadas desse acesso e desses híbridos, a resistência ao PepYMV não esteve associada ao marcador CAPS. O acesso CM?334?UFV ('Criollo de Morelos?334', de Viçosa, MG) distinguiu-se do CM?334?INRA ('Criollo de Morelos?334', da França); embora ambos os acessos tenham sido resistentes ao PepYMV, apenas em CM?334?INRA foi encontrada a associação da resistência com a banda de 444 pb

Avaliação do período anterior à interferencia de plantas daninhas para cultura da cebola transplantada na região do arenito caiuá.

O objetivo deste trabalho foi identificar o periodo anterior à interferencia das plantas daninhas na cultura da cebola transplantada em duas épocas na região do Arenito Caiuá

Spraying deposits using different nozzles and application volumes for pest management of cotton at reproductive stage.

With the growing need for greater operational capacity, information about the effect of application volume and spray nozzles on the quality of pesticide application are essential to obtain greater efficiency in pest management in cotton crops. This study aimed to assess the effect of the spraying volume and nozzles on the deposition of spray solution on cotton crops at the reproductive stage. The treatments of the first experiment correspond to the 55, 67, 140 and 194 L ha-1 volumes obtained by variation of the displacement speed using the XR11004 flat fan nozzle. In the second assay the treatments corresponded to the applications of MGA9004 (hollow cone), XR11004 (flat fan), AIXR11004 (air induction flat fan) and CVIA04 (air induction hollow cone) nozzles with 120 L ha-1. An artificial brilliant blue food dye (FD&C 1) was used as a tracer (2.5 g L-1) to determine the deposited volumes on the leaves of the upper, middle and lower third of cotton plants. The results showed that increase in the application volume contributed to obtain the larger deposits in the upper third of the cotton crop during its reproductive phase, especially up to 140 L ha-1, but did not exhibit a significant increase of the deposition in the middle and lower thirds of the plants. The MGA9004, XR11004 and AIXR11004 nozzles provided the largest deposits in the three plant sectors. The flat fan nozzles resulted in greater uniformity of deposits in the upper and middle thirds of the plants

Metallicity in the Galactic Center: The Arches cluster

We present a quantitative spectral analysis of five very massive stars in the Arches cluster, located near the Galactic center, to determine stellar parameters, stellar wind properties and, most importantly, metallicity content. The analysis uses a new technique, presented here for the first time, and uses line-blanketed NLTE wind/atmosphere models fit to high-resolution near-infrared spectra of late-type nitrogen-rich Wolf-Rayet stars and OfI+ stars in the cluster. It relies on the fact that massive stars reach a maximum nitrogen abundance that is related to initial metallicity when they are in the WNL phase. We determine the present-day nitrogen abundance of the WNL stars in the Arches cluster to be 1.6% (mass fraction) and constrain the stellar metallicity in the cluster to be solar. This result is invariant to assumptions about the mass-luminosity relationship, the mass-loss rates, and rotation speeds. In addition, from this analysis, we find the age of the Arches cluster to be 2-2.5Myr, assuming coeval formation

Abundance Gradients and the Formation of the Milky Way

In this paper we adopt a chemical evolution model, which is an improved version of the Chiappini, Matteucci and Gratton (1997) model, assuming two main accretion episodes for the formation of the Galaxy. The present model takes into account in more detail than previously the halo density distribution and explores the effects of a threshold density in the star formation process, during both the halo and disk phases. In the comparison between model predictions and available data, we have focused our attention on abundance gradients as well as gas, stellar and star formation rate distributions along the disk. We suggest that the mechanism for the formation of the halo leaves detectable imprints on the chemical properties of the outer regions of the disk, whereas the evolution of the halo and the inner disk are almost completely disentangled. This is due to the fact that the halo and disk densities are comparable at large Galactocentric distances and therefore the gas lost from the halo can substantially contribute to building up the outer disk. We also show that the existence of a threshold density for the star formation rate, both in the halo and disk phase, is necessary to reproduce the majority of observational data in the solar vicinity and in the whole disk. Moreover, we predict that the abundance gradients along the Galactic disk must have increased with time and that the average [alpha/Fe] ratio in stars (halo plus disk) slightly decrease going from 4 to 10 Kpcs from the Galactic center. We also show that the same ratios increase substantially towards the outermost disk regions and the expected scatter in the stellar ages decreases, because the outermost regions are dominated by halo stars.Comment: 41 pages (including the figures), To be published in Ap

Methane emissions from nellore heifers under integrated crop llvestock forest systems.

Adoption of Integrated Crop-Livestock-Forestry Systems (ICLFS) has been encouraged as a greenhouse gases (GHG) mitigation measure in Brazil. Accurate estimate of enteric methane emission (ECH4) is essential to compute carbon footprint and, consequently, to improve the evaluation and design of GHG mitigation strategies for cattle production systems