Static potential in scalar QED3_3 with non-minimal coupling

Here we compute the static potential in scalar $QED_3$ at leading order in $1/N_f$. We show that the addition of a non-minimal coupling of Pauli-type (\eps j^{\mu}\partial^{\nu}A^{\alpha}), although it breaks parity, it does not change the analytic structure of the photon propagator and consequently the static potential remains logarithmic (confining) at large distances. The non-minimal coupling modifies the potential, however, at small charge separations giving rise to a repulsive force of short range between opposite sign charges, which is relevant for the existence of bound states. This effect is in agreement with a previous calculation based on M$\ddot{o}$ller scattering, but differently from such calculation we show here that the repulsion appears independently of the presence of a tree level Chern-Simons term which rather affects the large distance behavior of the potential turning it into constant.Comment: 13 pages, 3 figure

Fertilidade do solo em sistemas agroflorestais.

Discussão sobre o tema desenvolvimento sustentável ocupa grande espaço na sociedade devido ao declínio na qualidade de vida no meio rural e urbano. A perda de qualidade de vida associa-se à intensa degradação dos recursos naturais atrelada à modernização da agricultura e ao aumento populacional das cidades. A agricultura é função da interação de fatores socioambientais e naturais, englobando dimensões sociais, culturais, políticas e econômicas. O desafio para uma agricultura sustentável passa pelo ajuste das relações socioeconômicas que governam o que é produzido, como é produzido e para quem é produzido. Isto necessita de uma abordagem que integra os princípios agronômicos, ecológicos e socioeconômicos à compreensão e avaliação do efeito das tecnologias sobre os sistemas agrícolas e a sociedade como um todo.Palestra

Evaluation of Microencapsulation of The UFV-AREG1 Bacteriophage in Alginate-Ca Microcapsules using Microfluidic Devices

The indiscriminate use of antibiotics and the emergence of resistant microorganisms have become a major challenge for the food industry. The purpose of this work was to microencapsulate the bacteriophage UFV-AREG1 in a calcium alginate matrix using microfluidic devices and to study the viability and efficiency of retention. The microcapsules were added to gel of propylene glycol for use as an antimicrobial in the food industry. The technique showed the number of the phage encapsulation, yielding drops with an average 100-250 $\mu$m of diameter, 82.1 $\pm$ 2% retention efficiency and stability in the gel matrix for 21 days. The gel added to the microencapsulated phage showed efficiency (not detectable on the surface) in reducing bacterial contamination on the surface at a similar level to antimicrobial chemicals (alcohol 70%). Therefore, it was possible to microencapsulate bacteriophages in alginate-Ca and apply the microcapsules in gels for use as sanitizers in the food industry.Comment: 8 pages, 5 figure

Synaptotagmin 1 oligomers clamp and regulate different modes of neurotransmitter release

Release of neurotransmitters relies on submillisecond coupling of synaptic vesicle fusion to the triggering signal: AP-evoked presynaptic Ca2+ influx. The key player that controls exocytosis of the synaptic vesicle is the Ca2+ sensor synaptotagmin 1 (Syt1). While the Ca2+ activation of Syt1 has been extensively characterized, how Syt1 reversibly clamps vesicular fusion remains enigmatic. Here, using a targeted mutation combined with fluorescence imaging and electrophysiology, we show that the structural feature of Syt1 to self-oligomerize provides the molecular basis for clamping of spontaneous and asynchronous release but is not required for triggering of synchronous release. Our findings propose a mechanistic model that explains how Syt1 oligomers regulate different modes of transmitter release in neuronal synapses

Estabilidade de agregados e distribuição de carbono e nutrientes em Argissolo sob adubação orgânica e mineral.

O objetivo deste trabalho foi avaliar o impacto da adubacao organica e mineral sobre a estabilidade de agregados e a distribuicao de C, N e P, em classes de agregados de um Argissolo Vermelho-Amarelo. Os tratamentos consistiram de 0 e 40 m3 ha.1 por ano de adubacao organica e de 0, 250 e 500 kg ha.1 de adubacao mineral N.P.K da formula 4.14.8. Uma area sob floresta atlantica foi utilizada como referencia. Amostras foram coletadas nas camadas de 0.10 e 10.20 cm. Houve predominio da classe de agregados entre 4 e 2 mm, que correspondeu a 39,7% do total de agregados separados por via seca no tratamento com composto organico. Os teores de C organico total para adubacao organica foram 17,5 e 36,7% maiores para as classes 4.2 e 0,105.0,25 mm. A adubacao organica contribuiu para teores de N e P totais de 43 e 38,7% (0.10 cm) e 35,4 e 36,8% (10.20 cm), maiores que os dos tratamentos sem adubo organico. A relacao carbono/nitrogenio se manteve constante entre as classes de agregados de um mesmo tratamento, enquanto a de carbono/fosforo reduziu com o uso de adubo organico ou mineral, em relacao a mata nativa. Os indices de estabilidade de agregados se correlacionaram positivamente aos teores de carbono organico total da classe 4.2 mm

Photon Orbital Angular Momentum and Mass in a Plasma Vortex

We analyse the Anderson-Higgs mechanism of photon mass acquisition in a plasma and study the contribution to the mass from the orbital angular momentum acquired by a beam of photons when it crosses a spatially structured charge distribution. To this end we apply Proca-Maxwell equations in a static plasma with a particular spatial distribution of free charges, notably a plasma vortex, that is able to impose orbital angular momentum (OAM) onto light. In addition to the mass acquisition of the conventional Anderson-Higgs mechanism, we find that the photon acquires an additional mass from the OAM and that this mass reduces the Proca photon mass.Comment: Four pages, no figures. Error corrections, improved notation, refined derivation