Browsing by Title

High-momentum configurations of nucleon pairs at short-distance are probed using measurements of the C-12(e, e p) and C-12(e, e pN) reactions (where N is either n or p), at high-Q(2) and x(B) > 1.1. The data span a missing-momentum range of 300-1000 MeV/c and are predominantly sensitive to the transition region of the strong nuclear interaction from a Tensor to Scalar interaction. The data are well reproduced by theoretical calculations using the Generalized Contact Formalism with both chiral and phenomenological nucleon-nucleon (NN) interaction models. This agreement suggests that the measured high missing-momentum protons up to 1000 MeV/c predominantly belong to short-ranged correlated (SRC) pairs. The measured C-12(e, e pN)/C-12(e, e p) and C-12(e, e pp)/C-12(e, e pn) cross-section ratios are consistent with a decrease in the fraction of proton-neutron SRC pairs and increase in the fraction of proton-proton SRC pairs with increasing missing momentum. This confirms the transition from an isospin-dependent tensor NN interaction at similar to 400 MeV/c to an isospin-independent scalar interaction at high-momentum around similar to 800 MeV/c as predicted by theoretical calculation. (C) 2021 The Author(s). Published by Elsevier B.V.

Esta tesis examina la generación procedural de contenido en videojuegos, enfocándose en la creación de niveles y mazmorras. Primero, se analizan las técnicas generales de generación procedural, seguidas de un estudio más detallado sobre la generación de niveles. El trabajo principal se centra en un Algoritmo Evolutivo de 2 Pasos (2-Step EA) para generar mazmorras con misiones de llaves y barreras. La primera fase del algoritmo configura el diseño básico de la mazmorra, y la segunda fase asigna llaves y barreras estratégicamente. Los resultados muestran que el algoritmo propuesto es efectivo en producir mazmorras de alta calidad y eficientes computacionalmente. Este enfoque ofrece una metodología sólida para la generación procedural de contenido dinámico.

We have conducted an entropy analysis in Alaska, a seismic-rich region in a subduction zone that exhibits a nontrivial behavior: the subduction arc alters the seismic activity from the eastern zone to the western zone, demonstrating a decrease in activity along the subduction. We analyze this zone through the Tsallis entropy and the mutability (or dynamic entropy) for the first time. Considering 13 870 seismic events after appropriate filtering, we analyzed a data set for the selected Alaska zone between 2000 and 2023. We have found agreement between the results for the two entropies. We have followed the value of the q parameter of the Tsallis entropy (Sq) finding values between 1.70 and 1.85, in concordance with values found in other seismic regions of the planet. The values of Sq decrease slightly over time but show a broad increase before the major earthquakes. Just opposite to Tsallis entropy, mutability shows a tendency to decrease prior to the major earthquakes. We used the simpler mutability method to further analyze this zone upon dividing the region into four subzones. The results show how mutability can identify the seismic activity in each zone. This study shows how an entropy approach can shed light on understanding the seismicity in subduction zones.

Next generation wireless and mobile networks will utilize millimeter-wave (mmWave) communication to achieve significantly increased data rates. However, since mmWave radio signals experience high path loss, the operation of mmWave networks will require accurate channel models designed for specific deployment sites. In this paper, we focus on the deployment area of the PAWR COSMOS testbed [1, 2] in New York City and report extensive 28 GHz channel measurements. These include over 24 million power measurements collected from over 1,500 links on 13 sidewalks in 3 different sites and in different settings during March–June, 2019. Using these measurements, we study the effects of the setup and environments (e.g., transmitter height and seasonal effects). We then discuss the obtained path gain values and their fitted lines, and the resulting effective azimuth beamforming gain. Based on these results, we also study the link SNR values that can be supported on individual sidewalks and the corresponding theoretically achievable data rates. We believe that the results can inform the COSMOS testbed deployment process and provide a benchmark for other deployment efforts in dense urban areas.

Malaria is an infectious disease caused by Plasmodium spp. parasites, with widespread drug resistance to most antimalarial drugs. We report the development of two 3D-QSAR models based on comparative molecular field analysis (CoMFA), comparative molecular similarity index analysis (CoMSIA), and a 2D-QSAR model, using a database of 349 compounds with activity against the P. falciparum 3D7 strain. The models were validated internally and externally, complying with all metrics (q2 > 0.5, r2test > 0.6, r2m > 0.5, etc.). The final models have shown the following statistical values: r2test CoMFA = 0.878, r2test CoMSIA = 0.876, and r2test 2D-QSAR = 0.845. The models were experimentally tested through the synthesis and biological evaluation of ten quinoline derivatives against P. falciparum 3D7. The CoMSIA and 2D-QSAR models outperformed CoMFA in terms of better predictive capacity (MAE = 0.7006, 0.4849, and 1.2803, respectively). The physicochemical and pharmacokinetic properties of three selected quinoline derivatives were similar to chloroquine. Finally, the compounds showed low cytotoxicity (IC50 > 100 µM) on human HepG2 cells. These results suggest that the QSAR models accurately predict the toxicological profile, correlating well with experimental in vivo data.

Electrical trees are one of the main mechanisms of degradation in solid polymeric insulation leading to the failure of high voltage equipment. They are interconnected networks of hollow tubules typically characterized from two-dimensional (2D) projections of their physical manifestation. It is shown that complete characterization requires a three-dimensional (3D) imaging technique such as X-ray computed tomography (XCT). We present a comprehensive set of parameters, quantitatively characterizing two types of tree topology, conventionally known as bush- and branchtype. Fractal dimensions are determined from 3D models and from 2D projections, and a simple quantitative relationship is established between the two for all but dense bush trees. Parameters such as number of nodes, segment length, tortuosity and branch angle are determined from tree skeletons. The parameters most strongly indicative of the differences in the structure are the number of branches, individual channel size, channel tortuosity, nodes per unit length and fractal dimension. Studying two stages of a bush tree's development showed that channels grew in width, while macroscopic parameters such as the fractal dimension and tortuosity were unchanged. These parameters provide a basis for tree growth models, and can shed light on growth mechanisms.

Los sistemas de sostenimiento con pilotes anclados discontinuos se utilizan con frecuencia en excavaciones profundas temporales en Santiago de Chile, debido a las condiciones geológicas caracterizadas por suelos gravo-arenosos rígidos y un nivel freático profundo. Esta investigación presenta un estudio integral que incluye el desarrollo de un modelo 3D para simular este tipo de excavaciones con pilotes anclados discontinuos. Se emplea el modelo constitutivo HS-Small para replicar con precisión las propiedades del suelo gravoso de Santiago, utilizando parámetros calibrados en base a ensayos geofísicos y de laboratorio de investigaciones previas. El objetivo principal del estudio es realizar un análisis dinámico utilizando dos ondas tipo Ricker y ondas sísmicas aplicadas en dos direcciones. Este análisis busca simular eventos sísmicos reales y evaluar la integridad estructural de los sistemas de sostenimiento bajo tales condiciones. Se emplean técnicas computacionales avanzadas para modelar con precisión el comportamiento de estos sistemas. Además, los resultados de los análisis dinámicos se comparan con las normativas chilenas para evaluar el desempeño estructural. Esta comparación es clave para determinar si las normas son conservadoras y si los sistemas cumplen con los criterios de seguridad y rendimiento requeridos. Los resultados obtenidos de los análisis dinámicos y la comparación con las normativas chilenas aportan información valiosa sobre el comportamiento y la eficacia de los sistemas de pilotes anclados discontinuos bajo cargas dinámicas. Se observa que los pilotes ubicados en esquinas experimentan menores desplazamientos y fuerzas internas, pero mayores empujes de suelo. Además, en algunos escenarios, las presiones del suelo inducidas dinámicamente superan las calculadas por la normativa, lo que sugiere oportunidades de mejora en las prácticas de diseño.

Abstract During a visual search through the Kepler main-field light curves, we have discovered a cataclysmic variable (CV) that experienced only a single 4-d long outburst over four years, rising to three times the quiescent flux. During the four years of non-outburst data the Kepler photometry of KIC 5608384 exhibits ellipsoidal light variations (‘ELVs’) with a ∼12 per cent amplitude and period of 8.7 h. Follow-up ground-based spectral observations have yielded a high-quality radial velocity curve and the associated mass function. Additionally, H α emission lines were present in the spectra even though these were taken while the source was presumably in quiescence. These emission lines are at least partially eclipsed by the companion K star. We utilize the available constraints of the mass function, the ELV amplitude, Roche lobe filling condition, and inferred radius of the K star to derive the system masses and orbital inclination angle: $M_{\rm wd} \simeq 0.46 \pm 0.02 \, \mathrm{M}_\odot$, $M_{\rm K} \simeq 0.41 \pm 0.03 \, \mathrm{M}_\odot$, and i ≳ 70°. The value of Mwd is the lowest reported for any accreting WD in a CV. We have also run binary evolution models using mesa to infer the most likely parameters of the pre-cataclysmic binary. Using the mass-transfer rates from the model evolution tracks we conclude that although the rates are close to the critical value for accretion disc stability, we expect KIC 5608384 to exhibit dwarf nova outbursts. We also conclude that the accreting white dwarf most likely descended from a hot subdwarf and, most notably, that this binary is one of the first bona fide examples of a progenitor of AM CVn binaries to have evolved through the CV channel.

In this paper, we develop a filtering algorithm for Wiener systems written in state-space form which considers correlated noise sources. The output non-linearity is approximated by using a piece-wise linear function. The probability function of the output signal conditioned to the system state is written as a Gaussian mixture distribution. A Gaussian sum filter algorithm to obtain the a posteriori probability density function of the state given the current and past output is developed. The associated statistics of the system state are obtained. The benefits of our proposal are illustrated via numerical simulations.

A novel Bayesian Hierarchical Network Model (BHNM) for ensemble forecasts of daily streamflow is presented that uses the spatial dependence induced by the river network topology and hydrometeorological variables from the upstream contributing area between station gauges. Model parameters are allowed to vary with time as functions of selected covariates for each day. Using the network structure to incorporate flow information from upstream gauges and precipitation from the immediate contributing area as covariates allows one to model the spatial correlation of flows simultaneously and parsimoniously. An application to daily monsoon period (July-August) streamflow at three gauges in the Narmada basin in central India for the period 1978-2014 is presented. The best set of covariates include daily streamflow from upstream gauges or from the gauge above the upstream gauges depending on travel times and daily precipitation from the area between two stations. The model validation indicates that the model is highly skillful relative to a null-model of generalized linear regression, which represents the analogous non-Bayesian forecast. The ensemble spread of BHNM accounts for the forecast uncertainty leading to reliable and skillful streamflow predictions.

This work presents a novel dc-dc bidirectional buck-boost converter between a battery pack and the inverter to regulate the dc-bus in an electric vehicle (EV) powertrain. The converter is based on the versatile buck-boost converter, which has shown an excellent performance in different fuel cell systems operating in low-voltage and hard-switching applications. Therefore, extending this converter to higher voltage applications such as the EV is a challenging task reported in this work. A high-efficiency step-up/step-down versatile converter can improve the EV powertrain efficiency for an extended range of electric motor (EM) speeds, comprising urban and highway driving cycles while allowing the operation under motoring and regeneration (regenerative brake) conditions. DC-bus voltage regulation is implemented using a digital two-loop control strategy. The inner feedback loop is based on the discrete-time sliding-mode current control (DSMCC) strategy, and for the outer feedback loop, a proportional-integral (PI) control is employed. Both digital control loops and the necessary transition mode strategy are implemented using a digital signal controller TMS320F28377S. The theoretical analysis has been validated on a 400 V 1.6 kW prototype and tested through simulation and an EV powertrain system testing.

Esta tesis aborda el problema conjunto de localización e inventario para el diseño de una red de distribución de dos niveles bajo demanda estocástica, en la que los centros de distribución candidatos operan con una política de revisión continua (r, Q), tiempos de entrega determinísticos y full backorders. El problema integra simultáneamente decisiones de apertura de centros de distribución, asignación de retail y definición de los parámetros óptimos de la política de inventario, incorporando además restricciones de nivel de servicio basadas en fill-rate en cada instalación. Con el fin de representar adecuadamente estas interacciones, se formula un modelo no convexo de programación no lineal entera mixta (MINLP) que describe explícitamente el inventario disponible, los pedidos pendientes esperados y las restricciones de nivel de servicio bajo demanda normalmente distribuida. Posteriormente, se desarrolla una reformulación convexa equivalente mediante la introducción de variables auxiliares para los términos de agregación de demanda, obteniéndose un problema convexo de programación no lineal entera mixta con restricciones de conos de segundo orden. Sobre esta base, se propone un enfoque de resolución que combina Outer Approximation y Branch & Cut para resolver el problema de manera eficiente. El enfoque propuesto permite estudiar el desempeño de ambos métodos comparando sus tiempos computacionales y gap de optimalidad para ver qué método resulta más conveniente para este tipo de problemas.

Since the start of the pandemic caused by the novel coronavirus, COVID-19, more than 106 million people have been infected and global deaths have surpassed 2.4 million. In Chile, the government restricted the activities and movement of people, organizations, and companies, under the concept of dynamic quarantine across municipalities for a predefined period of time. Chile is an interesting context to study because reports to have a higher quantity of infections per million people as well as a higher number of polymerize chain reaction (PCR) tests per million people. The higher testing rate means that Chile has good measurement of the contagious compared to other countries. Further, the heterogeneity of the social, economic, and demographic variables collected of each Chilean municipality provides a robust set of control data to better explain the contagious rate for each city. In this paper, we propose a framework to determine the effectiveness of the dynamic quarantine policy by analyzing different causal models (meta-learners and causal forest) including a time series pattern related to effective reproductive number. Additionally, we test the ability of the proposed framework to understand and explain the spread over benchmark traditional models and to interpret the Shapley Additive Explanations (SHAP) plots. The conclusions derived from the proposed framework provide important scientific information for government policymakers in disease control strategies, not only to analyze COVID-19 but to have a better model to determine social interventions for future outbreaks. (c) 2021 Elsevier B.V. All rights reserved.

We present a systematic search for periodic X-ray sources in ten Galactic globular clusters (GCs) using deep archival Chandra observations. By applying the Gregory–Loredo algorithm, we detect 28 periodic signals from 27 independent X-ray sources across six GCs, including 21 newly discovered X-ray periodic sources. The remaining four GCs show no periodic X-ray sources, primarily due to lower data sensitivity. Based on X-ray timing and spectral analyses, complemented by available optical and ultraviolet data, 21 of these periodic sources are identified as cataclysmic variables (CVs). Combined with 11 previously identified periodic CVs in 47 Tuc, this work constitutes the most comprehensive sample to date of GC CVs with probable orbital periods. The observed scarcity of old, short-period CVs in GCs compared to the Galactic inner bulge and solar neighbourhood is likely due to both selection effects favoring younger, dynamically formed systems and the suppression of primordial CV formation by stellar dynamical interactions typical of GC environments. Furthermore, a significant fraction of GC CVs—most with orbital periods below or within the CV period gap—are identified as probable magnetic CVs, while luminous intermediate polars appear underrepresented compared to the solar neighbourhood.

We find a characterization for Fano 4-folds X with Lefschetz defect delta(X) = 3: besides the product of two del Pezzo surfaces, they correspond to varieties admitting a conic bundle structure f : X -> Y with rho(X) - rho(Y) = 3. Moreover, we observe that all of these varieties are rational. We give the list of all possible targets of such contractions. Combining our results with the classification of toric Fano 4-folds due to Batyrev and Sato we provide explicit examples of Fano conic bundles from toric 4-folds with delta(X) = 3.

It is well known that beef produces volatile molecules. In this work, the detection of volatiles released by post-mortem bovine fast-twitch muscles (Musculus longissimus dorsi and Musculus cutaneus trunci) was done using GC/MS–SPME (gas chromatography/mass spectrum–solid-phase microextraction). The releases of volatile molecules were modeled against three factors (rigor-mortis, animal age and oxidative capacity) using a chemometrics approach (experimental design and partial least squares regression). The GC/MS–SPME technique produced more than 30 reproducible chromatographic peaks, but only 13 were associated significantly with two factors (rigor-mortis and animal age). The volatile profile was composed mainly of alcohols, aldehydes and alkanes. The factor “animal age” was the main variable related to the release of volatile molecules. The results strongly suggest that the release of volatile molecules change according to post-mortem metabolism and the animal age.

Convergence and diversity of solutions play an essential role in the design of multi-objective evolutionary algorithms (MOEAs). Among the available diversity mechanisms, the -dominance has shown a proper balance between convergence and diversity. When using -dominance, diversity is ensured by partitioning the objective space into boxes of size and, typically, a single solution is allowed at each of these boxes. However, there is no easy way to determine the precise value of . In this paper, we investigate how this goal can be achieved by using a co-evolutionary scheme that looks for the proper values of along the search without any need of a previous user’s knowledge. We include the proposed co-evolutionary scheme into an MOEA based on -dominance giving rise to a new MOEA. We evaluate the proposed MOEA solving standard benchmark test problems. According to our results, it is a promising alternative for solving multi-objective optimization problems because three main reasons: 1) it is competitive concerning stateof-the-art MOEAs, 2) it does not need extra information about the problem, and 3) it is computationally efficient

In this work, we explore an extension of the Standard Model designed to elucidate the fermion mass hierarchy, account for the dark matter relic abundance, and explain the observed matter-antimatter asymmetry in the universe. Beyond the Standard Model particle content, our model introduces additional scalars and fermions. Notably, the light active neutrinos and the first two generations of charged fermions acquire masses at the one-loop level. The model accommodates successful low-scale leptogenesis, permitting the mass of the decaying heavy right-handed neutrino to be as low as 10 TeV. We conduct a detailed analysis of the dark matter phenomenology and explore various interesting phenomenological implications. These include charged lepton flavor violation, muon and electron anomalous magnetic moments, constraints arising from electroweak precision observables, and implications for collider experiments.

Partial discharges (PDs) are one of the most important classes of ageing processes that occur within electrical insulation. PD detection is a standardized technique to qualify the state of the insulation in electric assets such as machines and power cables. Generally, the classical phase-resolved partial discharge (PRPD) patterns are used to perform the identification of the type of PD source when they are related to a specific degradation process and when the electrical noise level is low compared to the magnitudes of the PD signals. However, in practical applications such as measurements carried out in the field or in industrial environments, several PD sources and large noise signals are usually present simultaneously. In this study, three different inductive sensors have been used to evaluate and compare their performance in the detection and separation of multiple PD sources by applying the chromatic technique to each of the measured signals.

In medium- and low-voltage three-phase distribution networks, the load imbalance among the phases may compromise the network voltage symmetry. Inverter-interfaced distributed energy resources (DERs) can contribute to compensating for such imbalances by sharing the required negative sequence current while providing active power synchronized with the positive sequence voltage. However, positive and negative sequences are conventionally defined in a steady state and are not directly observed from the instantaneous voltage and current measurements at the DER unit’s point of connection. In this article, an estimation algorithm for sequence separation based on the Kalman filter is proposed. Furthermore, the proposed filter uses a complex vector representation of the asymmetric three-phase signals in synchronous coordinates to allow for the implementation of the Kalman filter in its stationary form, resulting in a simple dynamic filter able to estimate positive and negative sequences even during transient operation. The proposed stationary complex Kalman filter performs better than state-of-the-art techniques like DSOGI and very similarly to other Kalman filter implementations found in the literature but at a fraction of its computational cost (23.5%).