Multiple D4-D2-D0 on the Conifold and Wall-crossing with the Flop

We study the wall-crossing phenomena of D4-D2-D0 bound states with two units of D4-brane charge on the resolved conifold. We identify the walls of marginal stability and evaluate the discrete changes of the BPS indices by using the Kontsevich-Soibelman wall-crossing formula. In particular, we find that the field theories on D4-branes in two large radius limits are properly connected by the wall-crossings involving the flop transition of the conifold. We also find that in one of the large radius limits there are stable bound states of two D4-D2-D0 fragments.Comment: 24 pages, 4 figures; v2: typos corrected, minor changes, a reference adde

A amplitude de distribuição dos glóbulos vermelhos (rdw) pode ser considerado como um marcador da atividade da doença de Crohn?

Introduction: Recently, it has been suggested an association between red cell distribution width (RDW) and Crohn’s disease activity index (CDAI), but its use is not yet performed in daily clinical practice. Objectives: To determine whether RDW can be used as a marker of Crohn’s disease (CD) activity. Methods: This was a cross-sectional study including patients with CD, observed consecutively in an outpatient setting between January 1st and September 30th 2013. Blood cell indices, erythrocyte sedimentation rate (ESR), and C-reactive protein were measured. CD activity was determined by CDAI (active disease if CDAI ≥ 150). Associations were analyzed using logistic regression (SPSS version 20). Results: 119 patients (56% female) were included in the study with a mean age of 47 years (SD 15.2). Twenty patients (17%) had active disease. The median RDW was 14.0 (13---15). There was an association between RDW and disease activity (p = 0.044). After adjustment for age and gender, this association remained consistent (OR 1.20, 95% CI 1.03---1.39, p = 0.016). It was also found that the association between RDW and disease activity was independent of hemoglobin and ESR (OR 1.36, 95% CI 1.08---1.72, p = 0.01) and of biologic therapy (OR 1.19, 95% CI 1.03---1.37, p = 0.017). A RDW cutoff of 16% had a specificity and negative predictive value for CDAI ≥ 150 of 88% and 86%, respectively. Conclusion: In this study, RDW proved to be an independent and relatively specific marker of CD activity. These results may contribute to the implementation of this simple parameter, in clinical practice, aiming to help therapeutic decisions.Introduc¸ão: Recentemente, tem vindo a ser sugerida uma associac¸ão entre o valor de RDW e a atividade da doença de Crohn (DC), mas a sua utilização não está ainda implementada na prática clínica diária. Objetivos: Determinar se o RDW pode ser utilizado como marcador de atividade da DC. Métodos: Estudo transversal, em doentes com DC, observados consecutivamente em consulta de Doença Inflamatória Intestinal, entre 1 de janeiro e 30 de setembro de 2013. Analisaram-se índices do hemograma, proteína C reativa e velocidade de sedimentação. A gravidade da doença foi avaliada pelo Crohn’s disease activity index (doença ativa se CDAI≥150). As associações foram estudadas usando a regressão logística (SPSS Statistics V20). Resultados: Incluídos 119 doentes (56% do sexo feminino), com idade média de 47 anos (DP 15,2 anos). Vinte doentes (17%) tinham doença ativa. O valor do RDW mediano foi 14,0% (13-15). Verificou-se uma associação entre RDW e atividade da doença (p = 0,044). Após ajuste para a idade e o sexo, esta associação manteve-se consistente (OR 1,20; 95% CI 1,03-1,39; p = 0,016). Verificou-se ainda que a associação do valor do RDW com a atividade da doença foi independente do valor da hemoglobina e da velocidade de sedimentação (OR 1,36; 95% CI 1,08-1,72; p = 0,01) e da terapêutica biológica (OR 1,19; 95% CI 1,03-1,37; p = 0,017). Para um valor de corte de RDW de 16%, a especificidade e o valor preditivo negativo de CDAI≥ 150 foram de 88% e 86%, respetivamente. Conclusão: Neste estudo, o valor do RDW demonstrou ser um marcador independente e relativamente específico da atividade da doenc¸a de Crohn. Estes resultados poderão contribuir para a aplicação deste parâmetro simples, na prática clinica diária, visando auxiliar decisões terapêuticas

Wall-crossing of D4-D2-D0 and flop of the conifold

We discuss the wall-crossing of the BPS bound states of a non-compact holomorphic D4-brane with D2 and D0-branes on the conifold. We use the Kontsevich-Soibelman wall-crossing formula and analyze the BPS degeneracy in various chambers. In particular we obtain a relation between BPS degeneracies in two limiting attractor chambers related by a flop transition. Our result is consistent with known results and predicts BPS degeneracies in all chambers.Comment: 15 pages, 4 figures; v2: typos corrected; v3: minor changes, a reference added, version to be published in JHE

Collagen-Based Films Containing Liposome-Loaded Usnic Acid as Dressing for Dermal Burn Healing

The aim of this study was assess the effect of collagen-based films containing usnic acid as a wound dressing for dermal burn healing. Second-degree burn wounds were performed in forty-five Wistar rats, assigned into nine groups: COL—animals treated with collagen-based films; PHO—animals treated with collagen films containing empty liposomes; UAL—animals treated with collagen-based films containing usnic acid incorporated into liposomes. After 7, 14, and 21 days the animals were euthanized. On 7th day there was a moderate infiltration of neutrophils, in UAL, distributed throughout the burn wounds, whereas in COL and PHO, the severity of the reaction was slighter and still limited to the margins of the burn wounds. On the 14th day, the inflammatory reaction was less intense in UAL, with remarkable plasma cells infiltration. On the 21st day, there was reduction of the inflammation, which was predominantly composed of plasma cells in all groups, particularly in UAL. The use of the usnic acid provided more rapid substitution of type-III for type-I collagen on the 14th day, and improved the collagenization density on the 21st day. It was concluded that the use of reconstituted bovine type-I collagen-based films containing usnic acid improved burn healing process in rats

Super Weyl invariance: BPS equations from heterotic worldsheets

It is well-known that the beta functions on a string worldsheet correspond to the target space equations of motion, e.g. the Einstein equations. We show that the BPS equations, i.e. the conditions of vanishing supersymmetry variations of the space-time fermions, can be directly derived from the worldsheet. To this end we consider the RNS-formulation of the heterotic string with (2,0) supersymmetry, which describes a complex torsion target space that supports a holomorphic vector bundle. After a detailed account of its quantization and renormalization, we establish that the cancellation of the Weyl anomaly combined with (2,0) finiteness implies the heterotic BPS conditions: At the one loop level the geometry is required to be conformally balanced and the gauge background has to satisfy the Hermitean Yang-Mills equations.Comment: 1+31 pages LaTeX, 5 figures; final version, discussion relation Weyl invariance and (2,0) finiteness extended, typos correcte

Negative discriminant states in N=4 supersymmetric string theories

Single centered BPS black hole solutions exist only when the charge carried by the black hole has positive discriminant. On the other hand the exact dyon spectrum in heterotic string theory compactified on T^6 is known to contain states with negative discriminant. We show that all of these negative discriminant states can be accounted for as two centered black holes. Thus after the contribution to the index from the two centered black holes is subtracted from the total microscopic index, the index for states with negative discriminant vanishes even for finite values of charges, in agreement with the results from the black hole side. Bound state metamorphosis -- which requires us to identify certain apparently different two centered configurations according to a specific set of rules -- plays a crucial role in this analysis. We also generalize these results to a class of CHL string theories.Comment: LaTeX file, 32 pages; v2: reference added; v3: added new section 3.

A New Class of Four-Dimensional N=1 Supergravity with Non-minimal Derivative Couplings

In the N=1 four-dimensional new-minimal supergravity framework, we supersymmetrise the coupling of the scalar kinetic term to the Einstein tensor. This coupling, although introduces a non-minimal derivative interaction of curvature to matter, it does not introduce harmful higher-derivatives. For this construction, we employ off-shell chiral and real linear multiplets. Physical scalars are accommodated in the chiral multiplet whereas curvature resides in a linear one.Comment: 18 pages, version published at JHE

Using Genetic Diversity in Deep Root Systems of Perennial Forage Grasses and Rice to Capture Carbon in Tropical Soils

Agricultural soils have the potential not only to be sinks of carbon dioxide (CO2) but also to mitigate the emissions of this gas to the atmosphere, thus, alleviating global warming. Perennial tropical grasses and rice upland and lowland varieties exhibit a large untapped genetic diversity in their root systems (e.g., deep rooting ability, exudation rates and chemical composition) that, if unlocked, could contribute to increased food production in crop-livestock systems while enhancing soil organic carbon (SOC) in tropical regions. Naturebased solutions that improve crop adaptation and SOC storage in tropical soils could help to remove CO2 from the atmosphere and thereby benefit the global climate system. With the launch of Future Seeds, one of the world’s largest repositories of tropical crop varieties, the Bezos Earth Fund (BEF) granted a major project within the Program of Future of Food. The focus of this BEF funded project is to: (i) develop novel high-throughput phenotyping methods to evaluate genetic diversity of root systems of tropical grasses and rice; (ii) unravel the potential of root systems in crop-livestock systems to replenish soil organic carbon (SOC) in human-intervened areas in tropical soils; (iii) identify and target hotspots/agroecological niches for SOC storage in tropical soils; and (iv) build capacity in conducting research on root systems and SOC storage towards carbon farming in tropical regions. Implementation of land-based SOC storage practices/projects (through carbon markets) based on deep rooting ability of perennial tropical forage grasses and rice cultivars in crop-pasture rotational systems could significantly reduce net emissions from tropical soils