Comportamento de linhagens e cultivares de algodoeiro no Cerrado do Mato Grosso: resultados da safra 2003/2004.

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Concentration dependent structural, thermal, and optical features of Pr 3+-doped multicomponent tellurite glasses

Tuning the structural, thermal, and optical properties of low phonon energy glasses such as tellurite glasses (phonon energy ∼750 cm−1) with suitable rare earth dopants is a key issue in the fabrication of solid state lasers and optical amplifiers. In this work, (70-x) TeO2-10 WO3-10 ZnO-5 TiO2-5 Na2O-(x) Pr2O3 (x = 1.0–5.0 mol %) glasses were synthesized with high optical quality and characterized using X-ray diffraction (XRD), Scanning electron microscopy and Energy dispersive X-ray analysis (SEM-EDAX), Attenuated total reflectance-Fourier transform infrared (ATR-FTIR), Raman spectroscopy, Thermo-gravimetric analysis (TGA), Differential scanning calorimetry (DSC), optical absorption and luminescence techniques. The XRD and SEM measurements reveal the amorphous nature of all the prepared glasses and EDAX confirms all the elements present in the respective glasses. The presence of various functional groups such as stretching vibrations of Te[single bond]–O bonds in the [TeO4] trigonal bi-pyramid units, symmetrical stretching or bending vibrations of Te[single bond]–O[single bond]–Te or O[single bond]–Te[single bond]–O linkages at corner sharing sites along the chains of TeO4, TeO3 and TeO3+1, stretching vibrations of W[single bond]–O– and W[double bond; length as m-dash]═O bonds in WO4 tetragonal or WO6 octagonal units, vibrations of Zn[single bond]–O bonds from ZnO4 groups, including non-hygroscopic nature of the glasses are confirmed by ATR-FTIR and Raman spectra, respectively. For Pr3+-doped glasses, from the DSC profiles the glass transition temperature (Tg), onset crystallization temperature (Tx), crystallization temperature (Tc), and melting temperature (Tm) are identified and the evaluated thermal stability values varied in the temperature range of 169–220 °C with increasing Pr3+ doping concentration. Further, the Pr3+ -doped tellurite glasses demonstrate excellent glass stability with higher criterion of Hruby's value (HR) between 1.9 and 3.9. From the measured optical absorption spectrum, experimental oscillator strengths are calculated and used to evaluate three phenomenological Judd-Ofelt (J-O) intensity parameters Ω_λ_ (_λ_ = 2, 4 and 6) and respective radiative properties such as radiative transition probabilities (AR), the branching ratios (βR), and the radiative lifetime (τR) of metastable states for 1.0 mol % Pr3+-doped glass. Five main emission transitions at 3P0 → 3H5 (530 nm; green) with a shoulder at 543 nm, a weak band at 1D2 → 3H4 (592 nm; orange), 3P0 → 3H6 (615 nm; orange), 3P0 → 3F2 (649 nm; red), and 3P0 → 3F3 (686 nm; red) upon exciting at 486 nm (3H4 → 3P0) wavelength are observed from the luminescence spectra of Pr3+-doped tellurite glasses. Following the energy level diagram, Pr3+ ion concentration quenching on the luminescence intensity has been explained by a non-radiative energy transfer between the ions through cross-relaxation and energy migration processes. The concentration dependent structural, thermal, and optical behaviors of Pr 3+-doped tellurite glasses are understood and our systematic analysis could contribute towards the development of suitable optical devices fabrication. Raman spectra of all the synthesized glasses

Desempenho produtivo e parâmetros de carcaça de ovinos criados em pastagens de capim bufel recebendo doses crescentes de concentrado.

O presente estudo teve como objetivo avaliar o desempenho produtivo e parâmetros de carcaça de ovinos criados em pastagens de capim Bufel recebendo doses crescentes de suplemento concentrado

Adaptabilidade e estabilidade de cultivares de milho na zona agreste do nordeste brasileiro.

Realizou-se este trabalho visando conhecer a adaptabilidade e a estabilidade de diversas cultivares de milho quando submetidas a distintas condições ambientais do agreste nordestino

Morphological Divergence among Progeny of Macroptilium lathyroides Accessions from the Semi-Arid Region of Pernambuco, Brazil

Macroptilium is a legume genus with approximately 20 species, usually annual or biennial, herbaceous and distributed mainly in the Americas. It is widely used as a forage resource in grasslands and usually fixes atmospheric N. Martins et al. (2001) indicated that half-sib family selection with progeny testing is the most common plant breeding method used in Brazil. In the scientific literature, however, there are few studies dedicated to Macroptilium spp. This study evaluated morphological divergence among Macroptilium spp. progeny from accessions collected in 4 counties located in the semi-arid region of Pernambuco State, NE Brazil

The potential of Beauveria bassiana to control Raoiella indica (Acari: Tenuipalpidae) and its compatibility with predatory mites.

The red palm mite, Raoiella indica (Acari: Tenuipalpidae), is a serious pest of coconut plantations in tropical countries such as Brazil. Ecologically-sound control strategies have been sought for this pest; however, the potential of entomopathogenic fungi such as Beauveria bassiana (Hypocreales: Cordycipitaceae) in controlling this pest, as well as its compatibility with co-occurring natural enemies, remains poorly investigated. Thus, the present study was conducted to investigate the potential of four B. bassiana strains in controlling R. indica, as well as the compatibility of the most pathogenic fungal strain with the predatory mites Amblyseius largoensis and Typhlodromus ornatus (Acari: Phytoseiidae). Briefly, the pathogenicity of four B. bassiana strains (Bb-032, Bb-053, Bb-057 and Bb-086), isolated from coconut pests, were tested against R. indica. The B. bassiana strain Bb-032 was selected for further bioassays for being the most pathogenic to R. indica. The red palm mite survival and mean survival time drastically decreased when exposed to B. bassiana strain Bb-032 at both LC50 and LC80. In contrast, neither survival nor mean survival time of A. largoensis and T. ornatus were affected by the exposure to LC50 and LC80 of B. bassiana strain Bb-032. The fungal strain showed considerable selectivity to the two predatory mites; however, at its estimated LC80 for R. indica, reduced oviposition, egg viability and the instantaneous rate of increase (ri) were generally observed for both natural enemies. Therefore, B. bassiana holds potential promise for controlling R. indica in addition to being generally selective to non-target predatory mites