In vitro callogenesis from seedling leaves of mahogany (Swietenia macrophylla King).

8º IVCHB

Dynamics and Production of Forage in Winter Pasture under Continuous Grazing with Energetic Supplementation

This experiment was carried out at Federal University of Santa Maria, from July 09 to November 12, 1999 to evaluate the dynamics and production of forage of oat (Avena strigosa Schreb) and italian ryegrass (Lolium multiflorum Lam) mixture. The grazing system used was continuous with variable stocking rate to maintain 1500kg/ha of herbage mass in all treatments. The heifers were subjected to different levels of energetic supplementation. They are 0, 0.7 and 1.4% of LW/day. The pasture of oat and italian ryegrass presented an accumulation rate of 45.7, 55.1 and 50.0 kg of DM/ha /day and a total dry matter (DM) production of 7067, 7222 and 8137 kg/ha for 0, 0.7 and 1.4% of LW/day levels, respectively. The average percentage of leaf component was 8.26, 11.48 and 11.72 for oat and 23.12, 22.35 and 20.93 for Italian ryegrass at 0, 0.7 and 1.4% of LW/day levels, respectively. The supplementation neither affected the accumulation rate nor the total DM production of the pasture (P\u3e 0.05). The senescent material was lower (P\u3c 0.05) with no supplementation

Effect of Energetic Supplementation on Forage Losses in an Oat and Italian Ryegrass Pasture under Continuous Grazing

The experiment was conducted at UFSM-RS to quantify herbage losses in oat and Italian ryegrass mixture under continuous grazing by beef heifers. A continuous grazing method with variable stocking rate was utilized to maintain the same herbage mass, 1500 kg DM/ha, in all treatments. The treatments consisted of levels of energetic supplement (0, 0.7 and 1.4% of LW/day). The pasture was evaluated every 28 days, when forage not suitable for grazing was collected in points previously marked in experimental area. The daily losses of herbage mass were of 22.32, 18.98 and 21.16 kg of DM/ha/day, equivalent to 2.61, 1.91 and 1.41% of LW for levels of 0, 0.7 and 1.4% of LW/day, respectively. The results showed greater stocking rates in supplemented treatments, being 21.2% and 57.4% higher in 0.7 and 1.4% LW/day, respectively, than unsupplemented one

ELEMENTOS MINERAIS EM MADEIRAS DE EUCALIPTOS E ACÁCIA NEGRA E SUA INFLUÊNCIA NA INDÚSTRIA DE CELULOSE KRAFT BRANQUEADA

No ramo de papel e celulose os efluentes são um dos principais problemas e o consumo de água é crítico. Os circuitos internos estão sendo fechados e as fontes de contaminação precisam ser conhecidas. Uma das fontes de contaminação destes efluentes são os minerais da madeira, matéria-prima neste tipo de indústria. Neste trabalho foi avaliada a quantidade de alumínio, cálcio, cobre, ferro, potássio, magnésio, manganês, sódio, níquel e silício em madeiras de cinco espécies florestais, plantadas na região de Guaíba, RS, compreendendo Acacia mearnsii, Eucalyptus dunnii, Eucalyptus globulus, Eucalyptus grandis, Eucalyptus saligna. As amostras de madeira foram tratadas com digestão ácida e com carbonização em mufla, solubilizando em ácido para serem analisadas por ICP (Inductively Coupled Plasm). Foi observado que a quantidade de elementos é considerável e os principais elementos encontrados foram K, Ca, Na, Al, Mn, e Si. As espécies Eucalyptus grandis e Eucalyptus saligna mostraram melhor crescimento. Por outro lado, Eucalyptus globulus e Eucalyptus dunnii mostraram menor crescimento e maior teor de elementos. Pelo fato dessas espécies introduzirem maiores quantidades de elementos no processo de fabricação, devem conduzir a maiores problemas industriais. A Acacia mearnsii mostrou o menor nível para ferro, manganês e níquel, sendo uma boa opção para uso em branqueamento com oxigênio, ozônio e peróxido. O silício observado estava em baixa quantidade, o que leva a afirmar que há, na prática industrial, muita contaminação da madeira explorada com solo já que se encontram altos valores de sílica nos circuitos de licores. A entrada dos elementos minerais estudados em uma fábrica de celulose via madeira varia de 4 a 6 kg por tonelada de polpa não-branqueada produzida. Cuidados especiais devem ser tomados com as espécies com madeiras mais ricas em cinzas e elementos minerais e mais baixas eficiências nutricionais, como foi o caso de Eucalyptus dunnii e Eucalyptus globulus

Non-Commutative Gauge Theories and the Cosmological Constant

We discuss the issue of the cosmological constant in non-commutative non-supersymmetric gauge theories. In particular, in orbifold field theories non-commutativity acts as a UV cut-off. We suggest that in these theories quantum corrections give rise to a vacuum energy \rho, that is controlled by the non-commutativity parameter \theta, \rho ~ 1/theta^2 (only a soft logarithmic dependence on the Planck scale survives). We demonstrate our claim in a two-loop computation in field theory and by certain higher loop examples. Based on general expressions from string theory, we suggest that the vacuum energy is controlled by non-commutativity to all orders in perturbation theory.Comment: 11 pages, RevTex. 4 eps figures. v2: Typos corrected. To appear in Phys.Rev.

Resposta de sementes de Podocarpus lambertii ao congelamento: um modelo para a criopreservação de sementes de araucária.

Resumo

Ingestive Behaviour of Steers in Native Pastures in Southern Brazil

The Campos biome, particularly its native pastures, is the main resource for livestock production in southern Brazil (Boldrini, 1997). It has a huge floristic diversity in which more than 400 grass and 150 legume species are found. These pastures are very heterogeneous with horizontal as well as vertical structure. Hodgson (1985) stressed the importance of sward structure upon diet selection, emphasizing the difficulties animals could have to access all pasture layers in temperate pastures. This experiment investigates how variation in herbage allowance along the growing season influences the ingestive behaviour of steers

Effects of High-Fat Diet on eHSP72 and Extra-to-Intracellular HSP70 Levels in Mice Submitted to Exercise under Exposure to Fine Particulate Matter

Obesity, air pollution, and exercise induce alterations in the heat shock response (HSR), in both intracellular 70?kDa heat shock proteins (iHSP70) and the plasmatic extracellular form (eHSP72). Extra-to-intracellular HSP70 ratio (H-index?=?eHSP70/iHSP70 ratio) represents a candidate biomarker of subclinical health status. This study investigated the effects of moderate- and high-intensity exercise in the HSR and oxidative stress parameters, in obese mice exposed to fine particulate matter (PM2.5). Thirty-day-old male isogenic B6129F2/J mice were maintained for 16 weeks on standard chow or high-fat diet (HFD). Then, mice were exposed to either saline or 50?µg of PM2.5 by intranasal instillation and subsequently maintained at rest or subjected to moderate- or high-intensity swimming exercise. HFD mice exhibited high adiposity and glucose intolerance at week 16th. HFD mice submitted to moderate- or high-intensity exercise were not able to complete the exercise session and showed lower levels of eHSP70 and H-index, when compared to controls. PM2.5 exposure modified the glycaemic response to exercise and modified hematological responses in HFD mice. Our study suggests that obesity is a critical health condition for exercise prescription under PM2.5 exposure