Desenvolvimento da alfafa (Medicago sativa L.) sob diferentes doses de adubação potássica.

O objetivo deste trabalho foi estabelecer, para as condições da região Sudeste do Brasil, dose adequada de adubação potássica em cobertura para alfafa, a fim de se obter alta produção da cultura. A cv.Crioula foi semeada em 30/05/95, gastando-se 20kg de sementes por hectare, inoculadas com Rhizobium meliloti. Nove cortes foram realizados a 10cm da superfície do solo, sendo o primeiro (de uniformização) em 29/08/95 e o último em 08/05/96. A produção de matéria seca (MS) obtida dos tratamentos que receberam adubação potássica em cobertura aplicada após cada corte(20.40,60,80 e 100kg/ha de K2o), foi superior a testemunha, onde a planta permaneceu apenas com o potássio de manutenção aplicado ao plantio (150 kg/ha de Ká-dois-O

Efeitos da interferência de plantas daninhas no rendimento da cultura de alfafa (Medigaco sativa L.).

Com o objetivo de avaliar o efeito da interferência de uma comunidade infestante no rendimento da cultura de alfafa durante o periodo de um ano

Does e-learning policy drive change in Higher Education?: A case study relating models of organisational change to e-learning implementation

Due to the heightened competition introduced by the potential global market and the need for structural changes within organisations delivering e-content, e-learning policy is beginning to take on a more significant role within the context of educational policy per se. For this reason, it is becoming increasingly important to establish what effect such policies have and how they are achieved. This paper addresses this question, illustrating five ways in which change is understood (Fordist, evolutionary, ecological, community of practice and discourse-oriented) and then using this range of perspectives to explore how e-learning policy drives change (both organisational and pedagogic) within a selected higher education institution. The implications of this case are then discussed, and both methodological and pragmatic conclusions are drawn, considering the relative insights offered by the models and ways in which change around e-learning might be supported or promoted

Efeito de inoculante bacteriano sobre a qualidade da silagem e perda de matéria seca durante a ensilagem de sorgo.

O objetivo deste trabalho foi avaliar o efeito de um inoculante bacteriano comercial, contendo Lactobacillusplantarum, Streptococcus faecium e Pediococcus acidactili, sobre a qualidade da silagem e perda de matéria seca (MS) durante a ensilagem de sorgo (Sorghum bicolor L. Moench). Os tratamentos foram constituídos por dois tipos de silagem de sorgo duplo-propósito colhido no estádio farináceo: sem (controle) e com inoculante; três posições dentro de cada silo (região do terço inicial, região central e do terço final), correspondendo a três períodos de coleta (52,65 e 71 dias de fermentação) e três repetições em cada posição. Cada repetição foi constituída por um saco de tela plástica de malha fina, contendo aproximadamente 4 kg de forragem, sendo a parcela representada por uma amostra de aproximadamente 1 kg de forragem. A silagem com inoculante apresentou menor teor de cinza (matéria mineral), nitrogênio amoniacal e ácido láctico e níveis mais elevados de fibra em detergente neutro e fibra em detergente ácido. A silagem com inoculante não diferiu do controle em relação ao pH, à proteina bruta, energia bruta e porcentagem de perda da MS

Non-extensive processes associated with heating of the Galactic disc

We analyse the mechanisms ruling galactic disc heating through the dynamics of space velocities $U$, $V$ and $W$, extracted from the Geneva-Copenhagen catalogue. To do this, we use a model based on non-extensive statistical mechanics, where we derive the probability distribution functions that quantify the non-Gaussian effects. Furthermore, we find that the deviation $q-1$ at a given stellar age follows non-random behaviour. As a result, the $q$-index behaviour indicates that the vertical component $W$, perpendicular to the Galactic plane, does not ``heat up'' at random, which is in disagreement with previous works that attributed the evolution of $W$ to randomness. Finally, our results bring a new perspective to this matter and open the way for studying Galactic kinematic components through the eyes of more robust statistical models that consider non-Gaussian effects.Comment: 7 pages, 3 figures, 2 tables. Accepted to EP

Measuring Ages and Elemental Abundances from Unresolved Stellar Populations: Fe, Mg, C, N, and Ca

We present a method for determining mean light-weighted ages and abundances of Fe, Mg, C, N, and Ca, from medium resolution spectroscopy of unresolved stellar populations. The method, pioneered by Schiavon (2007), is implemented in a publicly available code called EZ_Ages. The method and error estimation are described, and the results tested for accuracy and consistency, by application to integrated spectra of well-known Galactic globular and open clusters. Ages and abundances from integrated light analysis agree with studies of resolved stars to within +/-0.1 dex for most clusters, and to within +/-0.2 dex for nearly all cases. The results are robust to the choice of Lick indices used in the fitting to within +/-0.1 dex, except for a few systematic deviations which are clearly categorized. The realism of our error estimates is checked through comparison with detailed Monte Carlo simulations. Finally, we apply EZ_Ages to the sample of galaxies presented in Thomas et al. (2005) and compare our derived values of age, [Fe/H], and [alpha/Fe] to their analysis. We find that [alpha/Fe] is very consistent between the two analyses, that ages are consistent for old (Age > 10 Gyr) populations, but show modest systematic differences at younger ages, and that [Fe/H] is fairly consistent, with small systematic differences related to the age systematics. Overall, EZ_Ages provides accurate estimates of fundamental parameters from medium resolution spectra of unresolved stellar populations in the old and intermediate-age regime, for the first time allowing quantitative estimates of the abundances of C, N, and Ca in these unresolved systems. The EZ_Ages code can be downloaded at http://www.ucolick.org/~graves/EZ_Ages.htmlComment: Accepted to ApJ