Exact Renormalization of Massless QED2

We perform the exact renormalization of two-dimensional massless gauge theories. Using these exact results we discuss the cluster property and confinement in both the anomalous and chiral Schwinger models.Comment: 14 pages, no figures, introduction and conclusions modifie

On the Renormalizability of Theories with Gauge Anomalies

We consider the detailed renormalization of two (1+1)-dimensional gauge theories which are quantized without preserving gauge invariance: the chiral and the "anomalous" Schwinger models. By regularizing the non-perturbative divergences that appear in fermionic Green's functions of both models, we show that the "tree level" photon propagator is ill-defined, thus forcing one to use the complete photon propagator in the loop expansion of these functions. We perform the renormalization of these divergences in both models to one loop level, defining it in a consistent and semi-perturbative sense that we propose in this paper.Comment: Final version, new title and abstract, introduction and conclusion rewritten, detailed semiperturbative discussion included, references added; to appear in International Journal of Modern Physics

Diffusion and mixing in gravity-driven dense granular flows

We study the transport properties of particles draining from a silo using imaging and direct particle tracking. The particle displacements show a universal transition from super-diffusion to normal diffusion, as a function of the distance fallen, independent of the flow speed. In the super-diffusive (but sub-ballistic) regime, which occurs before a particle falls through its diameter, the displacements have fat-tailed and anisotropic distributions. In the diffusive regime, we observe very slow cage breaking and Peclet numbers of order 100, contrary to the only previous microscopic model (based on diffusing voids). Overall, our experiments show that diffusion and mixing are dominated by geometry, consistent with fluctuating contact networks but not thermal collisions, as in normal fluids

Non-Commutative Gauge Theories and the Cosmological Constant

We discuss the issue of the cosmological constant in non-commutative non-supersymmetric gauge theories. In particular, in orbifold field theories non-commutativity acts as a UV cut-off. We suggest that in these theories quantum corrections give rise to a vacuum energy \rho, that is controlled by the non-commutativity parameter \theta, \rho ~ 1/theta^2 (only a soft logarithmic dependence on the Planck scale survives). We demonstrate our claim in a two-loop computation in field theory and by certain higher loop examples. Based on general expressions from string theory, we suggest that the vacuum energy is controlled by non-commutativity to all orders in perturbation theory.Comment: 11 pages, RevTex. 4 eps figures. v2: Typos corrected. To appear in Phys.Rev.

Biofortificação de selênio no crescimento de alho e avaliação de acúmulo de outros elementos nutrientes

Selenium (Se) is an essential element for humans and has anti-cancer function. Garlic can accumulate Se, so it is an option to Se supplementation in the human diet. The aim of this research was to study Se uptake and accumulation during garlic growth. Four doses of Na2 SeO4 and Na2 SeO3 solution were applied in the substrate (0, 5, 10 and 15 kg ha-1 Se) for one time in August 2014, with a random plot design and 3 replicates on garlic clone Rubi INTA. Three harvests were made, in September, October and December 2014. After each harvest, leaves, bulbs and roots were separated and conditioned (peeled and chopped), lyophilized, and finally acid-digested prior to Se, Mg, Zn, Mn, Cu, Fe, P and S determination by inductively coupled plasma mass spectrometry (ICP-MS). The Se accumulation was proportional to Se doses and did not affect garlic growth. Also, Se distribution among different organs was related to the garlic growth cycle. The Se presence decreased accumulation of Mg, Mn, Cu, Fe, P and S but increased Zn accumulation in plants. Garlic can be an important Se source to humans but it is important to consider Se-doses for biofortification.O selênio (Se) é elemento essencial para os seres humanos e é considerado anticancerígeno. Alho pode acumular Se, sendo, por isso, uma opção para a suplementação de Se na dieta humana. Assim, o objetivo deste trabalho foi estudar a captação e acúmulo de selênio durante o crescimento do alho e avaliar os efeitos da fortificação de Se. Quatro doses da solução de Se, nas formas de Na2 SeO4 e Na2 SeO3 foram aplicadas ao substrato em agosto de 2014 (0, 5, 10 e 15 kg ha-1 de Se) de uma única vez, em delineamento de parcela aleatória e 3 repetições no clone de alho Rubi INTA. Três colheitas foram feitas, em setembro, outubro e dezembro de 2014. Após cada colheita, as folhas, bulbos e raízes das amostras de alho resultantes de cada tratamento foram separadas e acondicionadas (descascadas e picadas), liofilizadas, e, finalmente, digeridas com ácido antes da determinação de Mg, Zn, Mn, Cu, Fe, P e S por espectrometria de massa com plasma indutivamente acoplado (ICP-MS). Os resultados confirmaram que o acúmulo de Se foi proporcional à magnitude das doses, e não afetou significativamente o crescimento do alho. Além disso, a distribuição de Se entre os diferentes compartimentos da planta foi relacionada ao ciclo de crescimento da planta de alho. A fortificação do alho com Se causou mudanças significativas, e induziu o acúmulo e distribuição de diferentes nutrientes, como Zn, Mg, Mn, Cu, Fe, P e S, mas aumentou o acúmulo de Zn nas plantas. O alho pode ser considerado fonte importante de Se para aumentar a ingestão deste elemento na dieta humana, mas é importante considerar as doses de Se para a biofortificação.Fil: Pérez, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Interdisciplinario de Ciencias Básicas. - Universidad Nacional de Cuyo. Instituto Interdisciplinario de Ciencias Básicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Química Analítica para Investigación y Desarrollo; ArgentinaFil: Lipinski, Víctor Mario. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Mendoza-San Juan. Estación Experimental Agropecuaria La Consulta; ArgentinaFil: Filippini, Maria Flavia Ramona. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Interdisciplinario de Ciencias Básicas. - Universidad Nacional de Cuyo. Instituto Interdisciplinario de Ciencias Básicas; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Química Analítica para Investigación y Desarrollo; ArgentinaFil: Chacón Madrid, Katherine. Universidade Estadual Do Campinas. Instituto de Química.; BrasilFil: Arruda, Marco Aurelio Z.. Universidade Estadual Do Campinas. Instituto de Química.; BrasilFil: Wuilloud, Rodolfo German. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Química Analítica para Investigación y Desarrollo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Interdisciplinario de Ciencias Básicas. - Universidad Nacional de Cuyo. Instituto Interdisciplinario de Ciencias Básicas; Argentin

Environmental drivers of distribution and reef development of the Mediterranean coral Cladocora caespitosa

Cladocora caespitosa is the only Mediterranean scleractinian similar to tropical reef-building corals. While this species is part of the recent fossil history of the Mediterranean Sea, it is currently considered endangered due to its decline during the last decades. Environmental factors affecting the distribution and persistence of extensive bank reefs of this endemic species across its whole geographic range are poorly understood. In this study, we examined the environmental response of C. caespitosa and its main types of assemblages using ecological niche modeling and ordination analysis. We also predicted other suitable areas for the occurrence of the species and assessed the conservation effectiveness of Mediterranean marine protected areas (MPAs) for this coral. We found that phosphate concentration and wave height were factors affecting both the occurrence of this versatile species and the distribution of its extensive bioconstructions in the Mediterranean Sea. A set of factors (diffuse attenuation coefficient, calcite and nitrate concentrations, mean wave height, sea surface temperature, and shape of the coast) likely act as environmental barriers preventing the species from expansion to the Atlantic Ocean and the Black Sea. Uncertainties in our large-scale statistical results and departures from previous physiological and ecological studies are also discussed under an integrative perspective. This study reveals that Mediterranean MPAs encompass eight of the ten banks and 16 of the 21 beds of C. caespitosa. Preservation of water clarity by avoiding phosphate discharges may improve the protection of this emblematic species.Spanish Ministry of Economy and Competitiveness [CTM2014-57949-R]info:eu-repo/semantics/publishedVersio

Lightweight bamboo structures - Report on 2021 International Collaboration on Bamboo Construction

2021 International Collaboration on Bamboo Construction was held from September 1 to December 1, 2021. The practice was held by the College of Civil Engineering of Nanjing Forestry University, University College London, International Bamboo and Rattan Organisation (INBAR) and co-organized by 6 international institutions and national companies of China. Two main bamboo structures were setup by the teachers and students in the campus of Nanjing Forestry University. More than 50 students attended the practice, including international students from different countries. The practice was held to deliver the feasibility and applicability of bamboo in various geometries and different spans, and different areas. Innovative technologies like BIM Revit Architecture and Sketchup were used for the design of bamboo structures. The main principle of the practice was that the raising of bamboo structures should be simple using a minimum of materials aside from bamboo. The results of the project contributed to the popularization of the use of bamboo in the architecture, engineering and construction sectors

Aspects of a planar nonbirefringent and CPT-even electrodynamics stemming from the Standard Model Extension

We have studied a (1+2)-dimensional Lorentz-violating model which is obtained from the dimensional reduction of the nonbirefringent sector of the CPT-even electrodynamics of the standard model extension (SME). The planar theory contains a gauge sector and a scalar sector which are linearly coupled by means of a Lorentz-invariance violating (LIV) vector, $S^{\mu}$, while the kinetic terms of both sectors are affected by the components of a Lorentz-violating symmetric tensor, $\kappa^{\mu\nu}$. The energy-momentum tensor reveals that both sectors present energy stability for sufficiently small values of the Lorentz-violating parameters. The full dispersion relation equations are exactly determined and analyzed for some special configurations of the LIV backgrounds, showing that the planar model is entirely nonbirefringent at any order in the LIV parameters. At first order, the gauge and scalar sectors are described by the same dispersion relations. Finally, the equations of motion have been solved in the stationary regime and at first order in the LIV parameters. It is observed that the Lorentz-violating parameters do not alter the asymptotical behavior of the electric and magnetic fields but induce an angular dependence which is not present in Maxwell's planar theory.Comment: Revtex style, 15 page

Two-loop Yang-Mills diagrams from superstring amplitudes

Starting from the superstring amplitude describing interactions among D-branes with a constant world-volume field strength, we present a detailed analysis of how the open string degeneration limits reproduce the corresponding field theory Feynman diagrams. A key ingredient in the string construction is represented by the twisted (Prym) super differentials, as their periods encode the information about the background field. We provide an efficient method to calculate perturbatively the determinant of the twisted period matrix in terms of sets of super-moduli appropriate to the degeneration limits. Using this result we show that there is a precise one-to-one correspondence between the degeneration of different factors in the superstring amplitudes and one-particle irreducible Feynman diagrams capturing the gauge theory effective action at the two-loop level.Comment: 42 pages plus appendices, 10 figure

Inherited Forms of Bladder Cancer: A review of Lynch Syndrome and Other Inherited Conditions

Environmental factors that play a role in the urothelial carcinogenesis have been well characterized. Current research is continuously exploring potential heritable forms of bladder cancer. Lynch syndrome is a well-known inheritable disease that increases the risk for a variety of cancers, including urothelial carcinomas. Screening of patients with known Lynch syndrome is important to evaluate for development of new primary tumors. Further study may provide more information on what level of follow-up each patient needs. Recent data suggest that mismatch repair mutations confer a greater risk for urothelial cancer. Additional large patient series as well as advancement of molecular testing may provide triage for Lynch syndrome patients in regards to the frequency and type of screening best suited for individual patient