Controle químico de azevém e buva na cultura da macieira.

A cultura da macieira é de grande importância para a economia mundial. O controle de plantas daninhas é de fundamental importância para que não ocorram perdas significativas na sua produtividade. Poucos são os herbicidas registrados para a cultura e muitos são os utilizados pelos produtores, sem conhecer ao certo os danos que podem causar à cultura, como fitotoxidez à planta, residual nos frutos, bem como alteração no peso e tamanho dos mesmos. .Dissertação (Mestrado em Produção Vegetal). Universidade do Estado de Santa Catarina, Centro de Ciências Agroveterinárias, Programa de Pós-graduação em Produção Vegetal, Lages, 2017. Orientador: Leonardo Bianco de Carvalho; Co-orientadora: Andrea de Rossi Rufato (CNPUV

Ising nematic phase in ultra-thin magnetic films: a Monte Carlo study

We study the critical properties of a two--dimensional Ising model with competing ferromagnetic exchange and dipolar interactions, which models an ultra-thin magnetic film with high out--of--plane anisotropy in the monolayer limit. We present numerical evidence showing that two different scenarios appear in the model for different values of the exchange to dipolar intensities ratio, namely, a single first order stripe - tetragonal phase transition or two phase transitions at different temperatures with an intermediate Ising nematic phase between the stripe and the tetragonal ones. Our results are very similar to those predicted by Abanov et al [Phys. Rev. B 51, 1023 (1995)], but suggest a much more complex critical behavior than the predicted by those authors for both the stripe-nematic and the nematic-tetragonal phase transitions. We also show that the presence of diverging free energy barriers at the stripe-nematic transition makes possible to obtain by slow cooling a metastable supercooled nematic state down to temperatures well below the transition one.Comment: 13 pages, 19 figure

Ammonium thiosulfate as blossom thinner in 'Maxi Gala' apple trees.

The objective of this work was to evaluate the feasibility of using ammonium thiosulfate as a chemical blossom thinner in 'Maxi Gala' apple (Malus domestica) trees and its effects on fruit quality. The experiment was carried out in an experimental orchard in the Southern Brazil, in a randomized complete block design, with five replicates. Ammonium thiosulfate was sprayed on the apple trees at the full bloom stage, at 0, 1.5, 2.5, and 3.5%. Evaluations were performed for the effects on crop load, fruit set, yield efficiency, and fruit quality parameters such as weight, shape, total soluble solids, seed number, flesh firmness, color, and russeting occurrence. Ammonium thiosulfate at 2.5% is effective to reduce crop load and to improve fruit quality. The thinning effect of ammonium thiosulfate is not dependent on the weather conditions during the crop season. The rate of 3.5% of ammonium thiosulfate causes overthinning and does not result in the improvement of fruit quality. Index terms: Malus domestica, ATS, blossom stage, flower thinning. Tiossulfato de amônio como raleante de floração em macieiras 'Maxi Gala' O objetivo deste trabalho foi avaliar a viabilidade de uso de tiossulfato de amônio, como raleante químico de floração, em macieiras 'Maxi Gala' (Malus domestica), e os seus efeitos sobre a qualidade dos frutos. O experimento foi realizado em pomar experimental no sul do Brasil, em delineamento de blocos ao acaso, com cinco repetições. O tiossulfato de amônio foi aplicado às macieiras em plena floração, a 0, 1,5, 2,5 e 3,5%. Foram feitas avaliações quanto aos efeitos sobre carga de frutos, frutificação efetiva, eficiência produtiva e parâmetros de qualidade de frutos como massa, formato, sólidos solúveis totais, número de sementes, firmeza de polpa, coloração e ocorrência de “russeting”. O tiossulfato de amônio a 2,5% é efetivo na redução da carga de frutos e no aumento da qualidade dos frutos. O efeito raleante do tiossulfato de amônio não é dependente das condições climáticas durante o período de raleio. A dose de 3,5% de tiossulfato de amônio causa raleio excessivo e não resulta em melhoria na qualidade dos frutos. Termos para indexação: Malus domestica, ATS, plena floração, raleio de flores.Título em português: Tiossulfato de amônio como raleante de floração em macieiras 'Maxi Gala'

A computational study of the configurational and vibrational contributions to the thermodynamics of substitutional alloys: the Ni3Al case

We have developed a methodology to study the thermodynamics of order-disorder transformations in n-component substitutional alloys that combines nonequilibrium methods, which can efficiently compute free energies, with Monte Carlo simulations, in which configurational and vibrational degrees of freedom are simultaneously considered on an equal footing basis. Furthermore, by appropriately constraining the system, we were able to compute the contributions to the vibrational entropy due to bond proportion, atomic size mismatch, and bulk volume effects. We have applied this methodology to calculate configurational and vibrational contributions to the entropy of the Ni3Al alloy as functions of temperature. We found that the bond proportion effect reduces the vibrational entropy at the order-disorder transition, while the size mismatch and the bond proportion effects combined do not change the vibrational entropy at the transition. We also found that the volume increase at the order-disorder transition causes a vibrational entropy increase of 0.08 kB/atom, which is significant when compared to the configurational entropy increase of 0.27 kB/atom. Our calculations indicate that the inclusion of vibrations reduces in about 30 percent the order-disorder transition temperature determined solely considering the configurational degrees of freedom.Comment: Already submitte

Lateral branch induction at nursery with growth regulators in ?maxi gala? apple trees grafted on four rootstocks.

Apple production in Southern Brazil has been increasing along the past decade, and part of this was due to the introduction of more adapted dwarfing rootstocks and consequently increased tree density in the orchards. Looking for obtaining early beariness, the use of branched nursery trees is one of the most important steps. The objective of this experiment was to determine the effects of plant the growth regulators Benzyladenine (BA), Benzyladenine + Gibberellic acid4+7, Thidiazuron, and Cyclanilide + Ethephon on the induction of lateral branches of ?Maxi Gala? apple trees at nursery, grafted on the rootstocks G.202, G.213, M.9, and Marubakaido with M.9 interstem. The growth regulators Benzyladenine (BA), and Benzyladenine + Gibberellic acid4+7 are the most effective on improving tree?s architecture and on increasing the number of spurs, for all scion-rootstock combinations tested. Plant growth regulators at elevated doses strongly interrupt apical dominance and stimulate an elevated number of lateral branches with narrower crotch angles