Temperature-induced spontaneous time-reversal symmetry breaking on the honeycomb lattice

Phase transitions involving spontaneous time-reversal symmetry breaking are studied on the honeycomb lattice at finite hole doping with next-nearest-neighbor repulsion. We derive an exact expression for the mean-field equation of state in closed form, valid at temperatures much less than the Fermi energy. Contrary to standard expectations, we find that thermally induced intraband particle-hole excitations can create and stabilize a uniform metallic phase with broken time-reversal symmetry as the temperature is raised in a region where the ground state is a trivial metal.

Entropic information for travelling solitons in Lorentz and CPT breaking systems

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Searches for supersymmetry using the M-T2 variable in hadronic events produced in pp collisions at 8 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The Morse oscillator generalised from supersymmetry

Using the factorisation method in supersymmetric quantum mechanics the author determines new potentials from the Morse oscillator. This method is applied although the ladder operators are not used.

Charge-symmetry breaking, rho-omega mixing, and the quark propagator

The momentum dependence of the ρ0-ω mixing contribution to charge-symmetry breaking (CSB) in the nucleon-nucleon interaction is compared in a variety of models. We focus in particular on the role that the structure of the quark propagator plays in the predicted behaviour of the ρ0-ω mixing amplitude. We present new results for a confining (entire) quark propagator and for typical propagators arising from explicit numerical solutions of quark Dyson-Schwinger equations We compare these to hadronic and free quark calculations The implications for our current understanding of CSB experiments is discussed.

SU(3) breaking and annihilation effects in the η and η′ masses

The mass splitting of the pseudoscalar mesons η and η′ is approached by taking into account the SU(3)-flavor symmetry breaking and annihilation effects. An extended version of the Schwinger sum rule and a mixing angle equal to -19.51° are obtained.

Dormancy breaking of the fig tree with hydrogen cyanamide and garlic extrate

The supply of cold hours needed to the dormancy breaking of shoots is the limiting factor for the cultivation of temperate climate fruit trees in warmer regions. In subtropical conditions, it is necessary to use chemical products to promote uniform sprouting. This research aimed at evaluating the effect of garlic extract and hydrogen cyanamide in sprouting, growth, production and production cycle of the fig tree. The experiment was conducted during the production cycles of 2011/12 and 2012/13. We used plants from the cultivar Roxo de Valinhos. Production pruning was made in the months of July/2011 and July/2012, and the following treatments were applied immediately after it: 2% hydrogen cyanamide and garlic extract in 4%, 8% and 12% doses, and a control treatment. Split plots were used as the experimental design, with five repetitions in blocks; each plot consisted of five treatments with hydrogen cyanamide, garlic extract and control; the subplots consisted of two production cycles. The use of hydrogen cyanamide promoted an anticipation of sprouting and the use of hydrogen cyanamide and garlic extract promoted a concentration of the productive period, when compared to the control. The estimated garlic extract dose that promoted the highest production per plant was 3%.

Calculable lepton masses, seesaw relations, and four neutrino mixings in a 3-3-1 model with an extra U(1) symmetry

We propose a scheme in which the masses of the heavier leptons obey seesaw type relations. The light lepton masses, except the electron and the electron neutrino ones, are generated by one loop level radiative corrections. We work in a version of the 3-3-1 electroweak model that predicts singlets (charged and neutral) of heavy leptons beyond the known ones. An extra U(1)(Omega) symmetry is introduced in order to avoid the light leptons getting masses at the tree level. The electron mass induces an explicit symmetry breaking at U(1)(Omega). We discuss also the mixing matrix among four neutrinos. The new energy scale required is not higher than a few TeV.

Superação de dormência das sementese controle químico de plantas de Momordicacharantia L

This experiment were performed to evaluate methods of seeds scarification for overcoming dormancy and the efficacy of six herbicides registered for sugarcane to control adult plants of Mcharantia. The experimental design was completely randomized, with four replications in both trials. The first trial is a factorial 2x8 (two times of seeds collection (2006 and 2007) with eight methods of breaking dormancy (mechanical scarification; 100% and 50% concentrated sulfuric acid; 2% potassium nitrate for three and six hours; heat dried at 60 degrees C; hot water at 60 degrees C and an untreated control). In the second trial evaluated the control of M. charantia through six different herbicides: Imazapic, Metsulfuron-methyl, Metribuzin, 2,4-D, Amicarbazone, Paraquat and a control without herbicide application. Thus, it can be concluded that the seeds were immersed in concentrated sulfuric acid for three minutes and potassium nitrate for three hours gave a higher percentage and germination speed and the herbicide Metribuzin reached, albeit belatedly, a total control of M. charantia.

Métodos de superação de dormência em sementes de Ipomoea e Merremia

Este trabalho objetivou avaliar os efeitos de métodos de superação de dormência sobre a germinação das sementes de Ipomoea grandifolia, I. hederifolia, I. nil, I. quamoclit, Merremia aegyptia e M. cissoides. Os tratamentos consistiram em ácido sulfúrico concentrado, nitrato de potássio, água quente e calor seco (50 ºC), lixa e fogo. Constatou-se que o ácido sulfúrico promoveu aumento na germinação das sementes de I. grandifolia (58, 37, 22 e 34%), I. hederifolia (76, 49, 82 e 55%), I. quamoclit (43, 33, 66 e 35%), I. nil (69, 79, 72 e 62%), M. cissoides (8, 19, 35 e 57%) e M. aegyptia (24, 64, 56 e 63%) após períodos de imersão de 5, 10, 15 e 20 minutos, respectivamente. A água (20 e 40 minutos), o calor seco (20 e 40 minutos) e o fogo melhoraram a germinação de I. grandifolia (68, 59, 62, 67 e 59%), M. cissoides (50, 52, 18, 25 e 46%) e M. aegyptia (54, 47, 21, 21 e 45%), respectivamente. O calor seco de 20 e 40 minutos melhorou a germinação de I. nil (49 e 36%), e o de 40 minutos, a de I. hederifolia (70%). O uso de nitrato de potássio e lixa não proporcionou melhoria na germinação das sementes.

Respostas de híbridos de milho ao nicosulfuron: I - aspectos biológlcos e da produção

Um ensaio de campo foi conduzido em 1994/95, na Fazenda de Ensino e Pesquisa da Faculdade de Ciências Agrárias e Veterinárias (UNESP) de Jaboticabal, SP, sendo os objetivos do trabalho comparar aspectos biológicos e produtivos de nove diferentes híbridos de milho, resultantes da aplicação da dose de 80 g.ha-1 de nicosulfuron {2- [[[[4,6-dimetoxi-2-pirimidina) amina] carboxil] amina] sulfonil] -N,N-dimetil-3-piridinacarboxiamida} em relação a plantas não tratadas. Verificou-se que o herbicida afetou significativamente alguns dos aspectos biológicos estudados (altura de plantas e de espigas, número de folhas, comprimento e largura de folhas e estande final) e não afetou os relacionados com a posição relativa das espigas, o diâmetro do colmo, as porcentagens de acamamento e de quebramento. A produtividade estimada dos híbridos tratados não foi afetada pela aplicação do produto, com exceção da estimada para o híbrido HT 2X.

Níveis nutricionais de cálcio para aves de corte ISA Label criadas sob semiconfinamento

Determinaram-se os níveis nutricionais de cálcio (Ca) para aves, machos e fêmeas, da linhagem ISA Label, nas fases inicial (um a 28 dias), crescimento (28 a 56 dias) e final (56 a 84 dias). Foram realizados três ensaios, um para cada fase, e, em cada ensaio, 480 aves com idade correspondente à fase de criação foram alojadas em 24 unidades experimentais com áreas de abrigo e de pastejo. Foi utilizado delineamento inteiramente ao acaso, em esquema fatorial 4x2 (Ca e sexo), totalizando oito tratamentos com três repetiç ões de 20 aves. Avaliaram-se: ganho de peso (GP); consumo de dieta (CD); conversão alimentar (CA); teores de fósforo (PT), de cálcio (CaT) e de cinzas na tíbia (CT) e resistência à quebra óssea (RQO). Na fase inicial, recomenda-se 1,16% de Ca na dieta, para aves de ambos os sexos, na fase de crescimento, 0,78 e 0,88% de Ca para machos e fêmeas, respectivamente, e, na fase final, 0,69% de Ca na dieta para ambos os sexos.

Temporal variability of soil CO2 emission after conventional and reduced tillage described by an exponential decay in time model

A quantificação do impacto das práticas de preparo sobre as perdas de carbono do solo é dependente da habilidade de se descrever a variabilidade temporal da emissão de CO2 do solo após preparo. Tem sido sugerido que as grandes quantidades de CO2 emitido após o preparo do solo podem servir como um indicador das modificações nos estoques de carbono do solo em longo termo. Neste trabalho é apresentado um modelo de duas partes baseado na temperatura e na umidade do solo e que inclui um termo exponencial decrescente do tempo que é eficiente no ajuste das emissões intermediárias após preparo: arado de disco seguido de uma passagem com a grade niveladora (convencional) e escarificador de arrasto seguido da passagem com rolo destorroador (reduzido). As emissões após o preparo do solo são descritas utilizando-se estimativa não linear com um coeficiente de determinação (R²) tão alto quanto 0.98 após preparo reduzido. Os resultados indicam que nas previsões da emissão de CO2 após o preparo do solo é importante considerar um termo exponencial decrescente no tempo após preparo.

Influence of early quantitative food restriction on long bone growth at different environmental temperatures in broiler chickens

1. This investigation was carried out to study the influence of early quantitative food restriction (40% of ad libitum intake from 7 to 14 d of age) and environmental rearing temperature (thermoneutral, cold and hot) on long bone (tibia, femur and humerus) development in broiler chickens.2. Tibia, femur and humerus were obtained at the ages of 14, 21, 28, 35 and 42 d; and the variables studied were: length and width (mm, expressed as absolute values), bone breaking strength (kgf) and bone weight/bone length index (BW/BL, mg/mm).3. All bone variables increased with bird age. Food restriction reduced bone length and width but did not affect bone weight. High environmental rearing temperature reduced bone length and width at 42 d of age. Bone strength was not affected by environmental temperature but the calculated BW/BL index was reduced by heat exposure.4. The findings suggest that food restriction and high environmental rearing temperature reduce long bone growth; bone breaking strength was affected by bird age but not by food restriction nor rearing ambient temperature.