Rare top decay and CP violation in THDM

We discuss the formalism of two Higgs doublet model type III with CP violation from CP-even CP-odd mixing in the neutral Higgs bosons. The flavor changing interactions among neutral Higgs bosons and fermions are presented at tree level in this type of model. These assumptions allow the study rare top decays mediated by neutral Higgs bosons, particularly we are interested in $t\rightarrow c l^+l^-$. For this process we estimated upper bounds of the branching ratios $\textrm{Br}(t\rightarrow c \tau^+\tau^-)$ of the order of $10^{-9}\sim 10^{-7}$ for a neutral Higgs boson mass of 125 GeV and $\tan\beta=1$, 1.5, 2, 2.5. For the case of $t\rightarrow c \tau^+\tau^-$ the number of possible events is estimated from 1 to 10 events which could be observed in future experiments at LHC with a luminosity of 300 $\textrm{fb}^{-1}$ and 14 GeV for the energy of the center of mass. Also we estimate that the number of events for the process $t\rightarrow c l^+l^-$ in different scenarios is of order of $2500$.Comment: 8 pages, 5 figure

A network characterization of the interbank exposures in Peru

After the Global Financial Crisis (GFC), systemic risk measurement became crucial for policy makers as well as for academics. We have witnessed an important increase in the number of methodologies proposed. Among such proposals, DebtRank arose as perhaps one of the most relevant in this context, as it resorts to network modeling and captures the all-important aspect of interconnectedness in the financial system. Additionally, within the network modeling approach, there is the multilayer approach, which provides additional insights on the decomposition of systemic risk. In this paper, we apply a multilayer network analysis to study systemic risk in the Peruvian banking system by utilizing DebtRank centrality. The main contributions of this work are as follows: i) It fully characterizes the multilayer exposure network of the Peruvian banking system, and ii) it obtains the systemic risk profile of the banking system according to different types of exposures

Estudio in vivo de la oxidación mitocondrial en pacientes obesos tratados mediante restricción calórica

La restricción calórica es la terapia nutricional más frecuente en el tratamiento de la obesidad, cuya eficacia depende de la respuesta oxidativa del organismo para evitar la modificación del peso corporal. En este contexto, el objetivo del presente trabajo fue examinarin vivo la oxidación mitocondrial de voluntarios obesos, antes y después de adelgazar, utilizando el test en aliento con 2-ceto[1-13C]isocaproato. El estudio se realizó en 32 voluntarios de ambos sexos: 16 controles (índice de masa corporal: 19,0-27,0 kg/m2), y 16 obesos (índice de masa corporal: 30,0-41,6 kg/m2) que siguieron un período de restricción calórica (-500 kcal) durante 10 semanas. El test con 2-ceto[1-13C]isocaproato se realizó antes y después del tratamiento, a partir de la ingestión de 1 mg/kg de trazador y 20 mg/kg de L-leucina, disueltos en 200 mL de zumo de naranja. Antes y después de la ingestión (cada 10 minutos durante 2 horas), se tomaron muestras de aliento en las que se midió el enriquecimiento en13C mediante espectrometría de masas de relación isotópica. A partir de estas determinaciones se calculó el porcentaje de trazador oxidado en las mitocondrias (%13C). Los obesos tendieron a oxidar un porcentaje menor de trazador que los controles (25,1 ± 5,5% vs 27,5 ± 4,0% p = 0,175). Tras el período de intervención, la pérdida de peso medio fue -7,8 ± 3% (p < 0,001), y se acompañó de un aumento significativo en la oxidación del trazador (25,1 ± 5,5% vs 34,3 ± 5,2% p < 0,001). De hecho, el peso corporal y el porcentaje de 2-ceto[1-13C]isocaproato oxidado fueron inversamente proporcionales (r = -0,34, p = 0,018). Por tanto, el test en aliento con 2-ceto[113-C]isocaproato detectó in vivo la adaptación de la oxidación mitocondrial en obesos tratados mediante restricción calórica, ofreciendo una información complementaria sobre la pérdida de peso

Advanced measurement techniques for the characterization of ReRAM devices

In some Resistive Random Access Memories (ReRAM), which could become the next generation of non-volatile memories [1], the voltage-controlled high and low resistance states (HRS and LRS, respectively) are associated to the creation (Set) and disruption (Reset) of a conductive filament (CF) that locally connects (LRS) or disconnects (HRS) the electrodes [2]. Usually, a current limit (CL) must be fixed during the Set process. Typically, these devices are characterized using source measurement units (SMU) to measure the current through the device. However, most of the SMU have a low sampling rate (around 1sample/1ms) and the current limitation mechanism used by the equipment is not well understood. To overcome these limitations, in this work, a low-cost setup with large sampling rate (larger than 1sample/10μs) is presented which, in addition, includes a well-controlled wide-range current limiting unit, CLCU (Fig. 1). The system is suitable to capture fast transients during the Set/Reset processes (Fig. 2) and to detect HRS Random Telegraph Noise (RTN) unresolvable by SMUs (Fig. 3) [3]. These device-level measurements can be combined with a Conductive Atomic Force Microscope, to get information on CF properties that cannot be directly measured at device level, as, for example, the spatial distribution of current in the CF at LRS and HRS (Fig. 4) [4]. Please click Additional Files below to see the full abstract

Discovery of unusual pulsations in the cool, evolved Am stars HD 98851 and HD 102480

The chemically peculiar (CP) stars HD 98851 and HD 102480 have been discovered to be unusual pulsators during the ``Naini Tal Cape Survey'' programme to search for pulsational variability in CP stars. Time series photometric and spectroscopic observations of these newly discovered stars are reported here. Fourier analyses of the time series photometry reveal that HD 98851 is pulsating mainly with frequencies 0.208 mHz and 0.103 mHz, and HD 102480 is pulsating with frequencies 0.107 mHz, 0.156 mHz and 0.198 mHz. The frequency identifications are all subject to 1 d$^{-1}$ cycle count ambiguities. We have matched the observed low resolution spectra of HD 98851 and HD 102480 in the range 3500-7400 \AA with theoretical synthetic spectra using Kurucz models with solar metallicity and a micro-turbulent velocity 2 km s$^{-1}$. These yield $T_{eff}=7000\pm250$ K, log $g=3.5 \pm 0.5$ for HD 98851 and $T_{eff} = 6750 \pm 250$ K, log $g = 3.0 \pm 0.5$ for HD 102480. We determined the equivalent H-line spectral class of these stars to be F1 IV and F3 III/IV, respectively. A comparison of the location of HD 98851 and HD 102480 in the HR diagram with theoretical stellar evolutionary tracks indicates that both stars are about 1-Gyr-old, 2-$M_{\odot}$ stars that lie towards the red edge of the $\delta$ Sct instability strip. We conclude that HD 98851 and HD 102480 are cool, evolved Am pulsators. The light curves of these pulsating stars have alternating high and low amplitudes, nearly harmonic (or sub-harmonic) period ratios, high pulsational overtones and Am spectral types. This is unusual for both Am and $\delta$ Sct pulsators, making these stars interesting objects.Comment: 9 pages, 6 Figures, Accepted for publication in MNRA

Formación Docente en Robótica

Este trabajo presenta una propuesta didáctica basada en proyectos diseñada para que docentes de primaria y secundaria sin experiencia previa en robótica educativa, puedan aprender sobre componentes básicos de hardware y su relación con el software en un curso de dos meses de duración con 4 clases virtuales y 3 presenciales. El curso es parte de una Especialización en Programación de dos años de duración. Analizamos los principales aspectos de la propuesta y los resultados en términos de las producciones que lograron los docentes y sus valoraciones del curso'