Freed-Witten anomaly in general flux compactification

Turning on a NS-NS three-form flux in a compact space drives some D-branes to be either Freed-Witten anomalous or unstable to decay into fluxes by the appearance of instantonic branes. By applying T-duality on a toroidal compactification, the NS-flux is transformed into metric fluxes. We propose a T-dual version of the Atiyah-Hirzebruch Spectral Sequence upon which we describe the Freed-Witten anomaly and the brane-flux transition driven by NS and metric fluxes in a twisted torus. The required conditions to cancel the anomaly and the appearance of new instantonic branes are also described. In addition, we give an example in which all D6-branes wrapping Freed-Witten anomaly-free three-cycles in the twisted torus T^6/Z(2)XZ(2) are nevertheless unstable to be transformed into fluxes. Evenmore we find a topological transformation between RR, NS-NS and metric fluxes driven by a chain of instantonic branes.Comment: v3: Shortened version. Examples added. Main results unchange

Quantum-secured imaging

We have built an imaging system that uses a photon's position or time-of-flight information to image an object, while using the photon's polarization for security. This ability allows us to obtain an image which is secure against an attack in which the object being imaged intercepts and resends the imaging photons with modified information. Popularly known as "jamming," this type of attack is commonly directed at active imaging systems such as radar. In order to jam our imaging system, the object must disturb the delicate quantum state of the imaging photons, thus introducing statistical errors that reveal its activity.Comment: 10 pages (double spaced), 5 figure

Exploring New Molecular Targets in Advanced Ovarian Cancer: The Aryl Hydrocarbon Receptor (AhR) and Antitumor Benzothiazole Ligands as Potential Therapeutic Candidates

Antitumor benzothiazoles, including 2-(4-amino-3-methylphenyl)-5-fluorobenzothiazole (5F 203; NSC 703786), non-fluorinated parent compound DF 203 (NSC 674495), and Phortress (NSC 710305), the lysyl amide prodrug of 5F 203, are experimental anticancer agents with activity in ovarian and breast cancer models in vitro and in vivo. These compounds require (and induce their own) metabolism by cytochrome P450 (CYP) enzymes (e.g., CYP1A1) for antitumor action. The aryl hydrocarbon receptor (AhR) is the main transcriptional regulator of CYP1A1, and we have previously demonstrated that DF 203 and 5F 203 are potent AhR ligands and trigger activation of AhR signaling in sensitive breast and ovarian cancer cells, causing nuclear translocation of AhR. We propose that AhR may represent a new molecular target in the treatment of ovarian tumors, and 5F 203 may exemplify a potential novel treatment. Furthermore, putative biomarkers of sensitivity to this agent have been identified

Modelo discreto 3d para mejoramiento del contraste térmico y estimación de profundidad de defectos en láminas de CFRP

Abstract Two finite difference discretization approaches of the Fourier’s 3D heat propagation model are introduced, from which a new technique is proposed to enhance the thermal contrast of infrared sequences of images acquired from pulsed active thermography experiment for non-destructive testing of CFRP slabs. The discrete models defined are easily adaptable to a spatial filter structure, which can be applied to each image of the infrared sequence to obtain a better contrast between possible internal flaws and sound regions of material, and hence, a better probability of flaws detection. The performance of the technique proposed is evaluated using artificial thermal sequences generated by ThermoCalc6L, software that is able to compute dynamic thermal distributions in anisotropic layered solids, simulating internal defects and different excitation sets. Results show that this technique offers a better contrast between defects and image background than other relevant techniques like modified-differential absolute contrast, and a potentially faster execution than techniques based on thermal distribution reconstruction like the 3D thermal filtering method. Resumen Se introducen dos aproximaciones por diferencias finitas al modelo clásico de Fourier de propagación del calor en 3D a partir de las cuales se propone una nueva técnica para mejorar el contraste térmico en secuencias de imágenes infrarrojas adquiridas a partir de experimentos de termografía activa pulsada para ensayo no destructivo de láminas delgadas de CFRP. Los modelos anteriores se adaptan fácilmente a una estructura de filtro espacial que puede aplicarse a cada imagen de la secuencia con el fin de obtener un mejor contraste entre posibles defectos internos y las regiones sanas del material, y por tanto, una mayor probabilidad de detección. El desempeño de la técnica propuesta se evalúa empleando secuencias artificiales sintetizadas con el software ThermoCalc6L, que permite computar las distribuciones de temperatura en láminas sólidas anisotrópicas, simulando defectos internos y diferentes esquemas de excitación. Los resultados muestran que la técnica propuesta ofrece un mejor contraste térmico que técnicas relevantes como el contraste absoluto diferencial modificado, y una velocidad potencialmente superior de ejecución sobre las técnicas basadas en la reconstrucción de la distribución térmica, como el caso del método de filtrado térmico 3D

The Exchange of Orientifold Two-Planes in M-theory

We propose an M-theory lift picture of the exchange among type IIA orientifold two-planes. This consists in wrapping a M5-brane on a three-cycle in the transverse space of the M-theory orientifold plane OM2. A flux quantization condition for the three-form self-dual field strength, on the worldvolume of the M5-brane is computed. This condition establishes the value which explains the relative charge between two different OM2-planes. Also, we find that the exchange of the four types of orientifold two-planes in string theory, has a common picture in M-theory. Moreover, we find that the assignment of the extra charge is fixed by cohomology and by the flux quantization of the field strength G in M-theory. We conclude that cohomology is sufficient to describe some orientifold properties in M-theory, that at string theory level, only K-theory is able to explain.Comment: 23+1 pages, 6 figures. v2: typos corrected, references adde

Seven surrogate precursors for modeling delayed neutron decay and predicting reactivity

The use of a different set of group decay constants for each fissionable nuclide complicates analysis of the dynamic behavior of fast reactors. A fast reactor containing six principal fissioning nuclides of uranium and plutonium must, in effect, be described by 36 delayed neutron groups. Additionally, the use of group decay constants that depend on the neutron energy spectrum makes it difficult to select values that describe the dynamic response of epithermal systems because virtually all delayed neutron activity measurements have been performed for fast or thermal-neutron-induced fission. Clearly, it would be desirable to have a single set of group decay constants that could be applied to all fissionable nuclides. A set of seven fixed decay constants is proposed herein. Each of the proposed decay constants is associated with a specific, dominant delayed neutron precursor. In effect, each group is represented by a single surrogate precursor. Using recently measured delayed neutron activities for U-235 and Np-237, the proposed set of decay constants actually improved the goodness of fit to the data. For other fissionable nuclides lacking experimental data, a method has been devised to obtain yields consistent with the proposed set of decay constants from the traditional six-group parameters. This transformation is accomplished without altering the traditional inferred reactivity scale

PRONÓSTICO DE DEMANDA DE ENERGÍA ELÉCTRICA USANDO PROCESOS GAUSSIANOS: UN ANÁLISIS COMPARATIVO: Short-Term Load Demand Forecasting using Gaussian Processes: A Comparative Analysis

Abstract—Load demand forecasting is an essential component for planning power systems, and it is an invaluable tool to grid operators or customers. Many methods have been proposed to provide reliable estimates of electric load demand, but few methods can address the problem of predicting energy demand from a probabilistic point of view. One of them is the Gaussian processes (GP) that considering an adequate covariance function are suitable tools to carry out this load forecasting task. In this article, we show how to use Gaussian processes to predict elec- trical energy demand. Additionally, we thoroughly test various covariance functions and provide a new one. The performance of the proposed methodology was tested on two real data sets, showing that GPs are competitive alternatives for short-term load demand forecasting compared to other state-of-the-art method

New treatments in renal cancer: The AhR ligands

Kidney cancer rapidly acquires resistance to antiangiogenic agents, such as sunitinib, developing an aggressive migratory phenotype (facilitated by c-Metsignal transduction). The Aryl hydrocarbon receptor (AhR) has recently been postulated as a molecular target for cancer treatment. Currently, there are two antitumor agent AhR ligands, with activity against renal cancer, that have been tested clinically: aminoflavone (AFP 464, NSC710464) and the benzothiazole (5F 203) prodrug Phortress. Our studies investigated the action of AFP 464, the aminoflavone pro-drug currently used in clinical trials, and 5F 203 on renal cancer cells, specifically examining their effects on cell cycle progression, apoptosis and cell migration. Both compounds caused cell cycle arrest and apoptosis but only 5F 203 potently inhibited the migration of TK-10, Caki-1 and SN12C cells as well as the migration signal transduction cascade, involving c-Met signaling, in TK-10 cells. Current investigations are focused on the development of nano-delivery vehicles, apoferritin-encapsulated benzothiazoles 5F 203 and GW610, for the treatment of renal cancer. These compounds have shown improved antitumor effects against TK-10 cells in vitro at lower concentrations compared with a naked agent.Fil: Itkin, Boris. Gobierno de la Ciudad de Buenos Aires. Hospital General de Agudos "Juan A. Fernández"; ArgentinaFil: Breen, Alastair. University of Nottingham; Estados UnidosFil: Turyanska, Lyudmila. University of Nottingham; Estados UnidosFil: Sandes, Eduardo Omar. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; ArgentinaFil: Bradshaw, Tracey D.. University of Nottingham; Estados UnidosFil: Loaiza Perez, Andrea Irene. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Oncología "Ángel H. Roffo"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentin