Evidence of Two Distinct Dynamic Critical Exponents in Connection with Vortex Physics

The dynamic critical exponent $z$ is determined from numerical simulations for the three-dimensional (3D) lattice Coulomb gas (LCG) and the 3D XY models with relaxational dynamics. It is suggested that the dynamics is characterized by two distinct dynamic critical indices $z_0$ and $z$ related to the divergence of the relaxation time $\tau$ by $\tau\propto \xi^{z_0}$ and $\tau\propto k^{-z}$, where $\xi$ is the correlation length and $k$ the wavevector. The values determined are $z_0\approx 1.5$ and $z\approx 1$ for the 3D LCG and $z_0\approx 1.5$ and $z\approx 2$ for the 3D XY model. It is argued that the nonlinear $IV$ exponent relates to $z_0$, whereas the usual Hohenberg-Halperin classification relates to $z$. Possible implications for the interpretation of experiments are pointed out. Comparisons with other existing results are discussed.Comment: to appear in PR

Effect of temperature on growth, photosynthesis and biochemical composition of Nannochloropsis oceanica, grown outdoors in tubular photobioreactors

Since temperature is an important factor affecting microalgal growth, photosynthetic rate and biomass composition, this study has accordingly focused on its effects on biomass yield and nighttime biomass loss, as well as photochemical changes, using Nannochloropsis oceanica as model species, grown in two outdoor 50-L tubular photobioreactors (PBR). In two independent trials, cultures were subjected to a diurnal light:dark cycle, under a constant temperature of 28 degrees C and, on the second trial, at 18 degrees C. Changes in culture performance were assessed by measuring growth, lipid and fatty acid composition of the biomass in both morning and evening. Our results revealed that N. oceanica shows a wide temperature tolerance with relevant nighttime biomass loss, that decreased at lower temperatures, at the expenses of its daily productivity. Fluorescence measurements revealed reversible damage to photosystem II in cells growing in the PBR under optimal thermal conditions, whereas microalgae grown at suboptimal ones exhibited an overall lower photosynthetic activity. Lipids were partially consumed overnight to support cell division and provide maintenance energy. Eicosapentaenoic acid (EPA) catabolism reached a maximum after the dark period, as opposed to their saturated counterparts; whereas lower temperatures led to higher EPA content which reached the maximum in the morning. These findings are relevant for the production of Nannochloropsis at industrial scale.European Cooperation in Science and Technology (COST) Action: European network for algal-bio-products (EUALGAE) [ES1408]Portuguese national funds from the Foundation for Science and Technology (FCT) [SFRH/BD/129952/2017]Laboratory for Process Engineering, Environment, Biotechnology and Energy -LEPABE -by the FCT/MCTES (PIDDAC) [UIDB/00511/2020]project: "LEPABE-2-ECO-INNOVATION" - North Portugal Regional Operational Program (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF) [NORTE-01-0145-FEDER-000005]project: "DINOSSAUR" - ERDF through Programa Operacional Competitividade e Internacionalizacao (COMPETE2020) [PTDC/BBB-EBB/1374/2014-POCI-01-0145-FEDER-016640]project: "SABANA"- European Union [727874][UID/Multi/04326/2019]info:eu-repo/semantics/publishedVersio

Continuous Time Monte Carlo and Spatial Ordering in Driven Lattice Gases: Application to Driven Vortices in Periodic Superconducting Networks

We consider the two dimensional (2D) classical lattice Coulomb gas as a model for magnetic field induced vortices in 2D superconducting networks. Two different dynamical rules are introduced to investigate driven diffusive steady states far from equilibrium as a function of temperature and driving force. The resulting steady states differ dramatically depending on which dynamical rule is used. We show that the commonly used driven diffusive Metropolis Monte Carlo dynamics contains unphysical intrinsic randomness that destroys the spatial ordering present in equilibrium (the vortex lattice) over most of the driven phase diagram. A continuous time Monte Carlo (CTMC) is then developed, which results in spatially ordered driven states at low temperature in finite sized systems. We show that CTMC is the natural discretization of continuum Langevin dynamics, and argue that it gives the correct physical behavior when the discrete grid represents the minima of a periodic potential. We use detailed finite size scaling methods to analyze the spatial structure of the steady states. We find that finite size effects can be subtle and that very long simulation times can be needed to arrive at the correct steady state. For particles moving on a triangular grid, we find that the ordered moving state is a transversely pinned smectic that becomes unstable to an anisotropic liquid on sufficiently large length scales. For particles moving on a square grid, the moving state is a similar smectic at large drives, but we find evidence for a possible moving solid at lower drives. We find that the driven liquid on the square grid has long range hexatic order, and we explain this as a specifically non-equilibrium effect. We show that, in the liquid, fluctuations are diffusive in both the transverse and longitudinal directions.Comment: 29 pages, 35 figure

Ultraviolet and Infrared Divergences in Implicit Regularization: a Consistent Approach

Implicit Regularization is a 4-dimensional regularization initially conceived to treat ultraviolet divergences. It has been successfully tested in several instances in the literature, more specifically in those where Dimensional Regularization does not apply. In the present contribution we extend the method to handle infrared divergences as well. We show that the essential steps which rendered Implicit Regularization adequate in the case of ultraviolet divergences have their counterpart for infrared ones. Moreover we show that a new scale appears, typically an infrared scale which is completely independent of the ultraviolet one. Examples are given.Comment: 9 pages, version to appear in Mod. Phys. Lett.

Seletividade da cultura do milho ao herbicida clomazone por meio do uso de dietholate.

Com o objetivo de avaliar a seletividade de clomazone na cultura do milho através do uso de dietholate, foram instalados dois experimentos, sob condições de casa-de-vegetação e laboratório, na Embrapa Milho e Sorgo, Sete Lagoas, MG. Sementes do milho BRS 2223 foram tratadas ou não com dietholate, na proporção de 500 g para 100 Kg de semente. Os tratamentos herbicidas foram oito doses de clomazone (0,0; 62,5; 125,0; 250,0; 500,0; 1000,0; 2000,0; 4000,0; g ha-1). As plantas de milho provenientes de sementes não tratadas com dietholate apresentaram índices estimados de 50% de fitotoxicidade, aos 14 DAA, em função a dose de 1203 g h-1 de clomazone, enquanto que esse índice somente foi estimado nas plantas de milho provenientes de sementes tratadas com dietholate, em função da dose de 1921 g ha-1 de clomazone. As diferenças no acúmulo de matéria seca aérea das plantas de milho tratadas ou não com dietholate foram observadas a partir da dose de 2000 g ha-1 de clomazone. Reduções de 80% e 90% no acúmulo da matéria seca aérea foram detectadas com a dose de clomazone a 4000 g ha-1, em plantas provenientes de sementes tratadas ou não com dietholate, respectivamente. O teor de clorofila foi reduzido em 50% com a dose de 784 g ha-1 e 1740 g ha-1, em plantas provenientes de sementes com ou sem dietholate, respectivamente. Em experimento in vitro, sementes tratadas na mesma proporção com dietholate foram crescidas em meio de cultura com a adição de clomazone (4, 8, 16, 32 e 64 ppm). As reduções estimadas do teor de clorofila nas plantas in vitro foram de 31,1% e 83,9, para as plantas provenientes de sementes tratadas ou não com dietholate, respectivamente. Os resultados permitem inferir que o uso de sementes dietholate aumenta a seletividade de cultivares de milho ao herbicida clomazone

Epidemiological Study of Mycobacterium bovis Infection in Buffalo and Cattle in Amazonas, Brazil.

Bovine Tuberculosis (BTB) is an endemic disease in about one hundred countries, affecting the economy causing a decrease in productivity, condemnation of meat, and damaging the credibility on international trade. Additionally, Mycobacterium bovis the major causative agent for BTB can also infect humans causing a variety of clinical presentations. The aim of this study was to determine BTB prevalence and the main risk factors for theMycobacterium bovis prevalence in cattle and buffalos in Amazonas State, Brazil. Tissue samples from 151 animals (45 buffalo and 106 cattle from five herds with buffalo only, 22 herds with cattle only, and 12 herds with buffalo and cattle) were obtained from slaughterhouses under State Veterinary Inspection. M. bovis were isolated on Stonebrink medium. The positive cultures were confirmed by polymerase chain reaction (PCR) testing. The apparent herd and animal prevalence rates were 56.4 and 5.40%, respectively. Regarding animal species, the apparent prevalence rates were 3% in cattle and 11.8% in buffalo. Generalized Linear Mixed Models (GLMM) with random effect were used to assess the association with risk factors on the prevalence. Species (buffalo), herds size (>100 animals) and the presence of both species (buffalo and cattle) in the herd were the major risk factors for the infection by Mycobacterium bovis in the region. The findings reveal an urgent need for evidence-based effective intervention to reduce BTB prevalence in cattle and buffalo and prevent its spread to the human population. Studies are needed to understand why buffalo are more likely to be infected by M. bovis than cattle in Amazon. Recommendations for zoning, use of data from the inspection services to generate information regarding BTB focus, adoption of epidemiological tools, and discouragement of practices that promote the mixing of cattle and buffalo, were made

Critical Behavior of the Flux-line Tension in Extreme Type-II Superconductors

The entropic corrections to the flux-line energy of extreme type-II superconductors are computed using a schematic dual Villain model description of the flux quanta. We find that the temperature profile of the lower-critical field vanishes polynomially at the transition with an exponent $\nu\cong 2/3$ in the isotropic case, while it exhibits an inflection point for the case of weakly coupled layers in parallel magnetic field. It is argued that vestiges of these effects have already been observed in high-temperature superconductors.Comment: 12 pages of plain TeX, 2 postscipt figures, to appear in Phys. Rev.

Effects of a Recurrent Selection Scheme, Applied to an Interspecific Hybrid \u3cem\u3ePennisetum Purpureum\u3c/em\u3e Schum. (Elephantgrass) \u3cem\u3ex Pennisetum Glaucum\u3c/em\u3e (L.) R. Br. Stuntz (Pearl Millet), on Several Seed Quality Parameters

Elephantgrass cultivars and introductions show practically no viable pure seeds and their uses in cultivated grasslands are exclusively dependent on vegetative propagation. Therefore, in large areas, sowing operation costs make unfeasible setting up new pastures. On the other hand, pearl millet is a high seed producer species though presenting some forage constraints (poor forage production, low regrowth potential after cutting or grazing and low field persistence). Recently, an hexaploid interespecific hybrid between the two species was developed (Schank & Diz, 1996), which is able to produce viable pure seeds, in variable amounts according to the genotype considered (Diz & Schank, 1995). This research aimed to check several seed quality parameters in two selected populations, derived from the original F2 interespecific hybrid population