bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factores institucionales, pedagógicos, psicosociales y sociodemográficos asociados al rendimiento académico en la Universidad de Costa Rica: un análisis multinivel
Authors: Montero Rojas Eiliana , Villalobos Palma Jeannette , Valverde Bermúdez Astrid 
Published: December 2014

Se realizó un análisis multinivel para predecir calificaciones finales en cursos de carrera, para una muestra estratificada, por áreas académicas, de 848 estudiantes de la Universidad de Costa Rica. Se utilizaron como variables independientes un conjunto de factores en dimensiones institucionales, sociodemográficas, psicosociales y pedagógicas. El mejor predictor fue el Promedio de Admisión, medida que combina notas de secundaria y el puntaje en una prueba de habilidades de razonamiento. También variables no cognitivas resultaron explicativas, siendo la más importante el puntaje de una escala de inteligencia emocional. La metodología empleada por el (la) docente mostró asimismo poder explicativo.
Análisis de los tipos de respuestas de alumnos universitarios en la lectura de imágenes sobre movimiento
Authors: Aguilar Susana , Maturano Carla , Nuñez Graciela 
Published: December 2014

Este trabajo indaga los mecanismos que utilizan los estudiantes ante la información contenida en imágenes de libros de Ciencias acerca del movimiento de los cuerpos. Entre los factores que intervienen en las interpretaciones de imágenes se encuentran: concepciones alternativas de los sujetos, particularidades de los datos y estrategias de abordaje del contenido. Para realizar la indagación se diseñaron y aplicaron pruebas antes y después de la enseñanza. Los resultados obtenidos muestran un tratamiento superficial de los datos que ofrecen las imágenes y la influencia del grado de conicidad en el abordaje de la información contenida en ellas.
Medición de la satisfacción laboral en la dirección escolar
Authors: Tejero-González Carlos Mª , Fernández-Díaz Mª José 
Published: December 2014

Este trabajo se articula en torno a dos objetivos: uno, diseñar una escala que permita medir la satisfacción laboral de los directores escolares y, dos, analizar el nivel de satisfacción de este colectivo. En consecuencia, se presenta un instrumento inédito, válido y fiable, con un Coeficiente Alfa igual a 0.80 y una estructura factorial que explica el 64% de la varianza del instrumento. Se concluye que los directores escolares muestran altos niveles de satisfacción, de forma jerarquizada: en primer lugar, con el equipo directivo y el personal de secretaría; en segundo lugar, con el profesorado y el alumnado/familias; y, finalmente, con las condiciones laborales. La variable sexo no muestra relación con la satisfacción del director pero sí el tipo de centro donde trabaja.
Necesidades de formación del profesorado universitario para la adaptación de su docencia al Espacio Europeo de Educación Superior (EEES)
Authors: Álvarez-Rojo Víctor , Romero Soledad , Gil- Flores Javier , Rodríguez-Santero Javier , Clares José , Asensio-Muñoz Inmaculada , Del-Frago Rakel , García-Lupión Beatriz , García-García Mercedes , González-González Daniel , Guardia Soledad , Ibarra Marisol , López-Fuentes Rafael , Rodríguez-Gómez Gregorio , Salmeron-Vilchez Purificación 
Published: December 2014

En este trabajo se presentan los resultados de una investigación llevada a cabo en cinco universidades españolas para diagnosticar las necesidades de formación en competencias del profesorado universitario. Utilizando técnicas de encuesta, aplicadas a una amplia muestra d profesorado de las cinco áreas de conocimiento, se han detectado necesidades de formación en seis bloques de competencias: a) la Planificación de la Docencia; b) el Desarrollo de la Docencia; c) la Evaluación; d) la Tutoría; e) la Gestión; f) la Formación Continua. Se han hallado diferencias significativas en las necesidades en función del área de conocimiento y las categorías profesionales.
Superconducting Electronics
Authors: Fourie Coenrad 
Published: December 2014

AbstractAn overview of the state of superconducting electronics is presented, starting with Josephson junction and dc SQUID as active devices. Analogue electronics for detectors, mixers, voltage standards and ultra‐sensitive magnetometers are discussed, as well as their application to fields ranging from radio astronomy through metrology to stand‐off security imaging. An overview of the fundamental operating principles of the most successful superconducting logic family, RSFQ, is given, followed by a critical look at the main problems facing large‐scale RSFQ integrated circuits. Contemporary methods to reduce static power consumption and magnetic fields from bias currents are highlighted, with a quick look at energy‐efficient SFQ (eSFQ), current recycling and on‐chip shielding in advanced fabrication processes as prime examples of such methods. Integrated circuit fabrication, cryocooling and other digital logic families are also discussed. We conclude with a look at energy‐efficient supercomputing and quantum computing as near‐future applications of superconducting electronics.
Revision of the EPICA Dome C CO2 record from 800 to 600 kyr before present
Authors: Bereiter Bernhard , Eggleston Sarah , Schmitt Jochen , Nehrbass‐Ahles Christoph , Stocker Thomas F. , Fischer Hubertus , Kipfstuhl Sepp , Chappellaz Jerome 
Published: December 2014

AbstractThe European Project for Ice Coring in Antarctica Dome ice core from Dome C (EDC) has allowed for the reconstruction of atmospheric CO2 concentrations for the last 800,000 years. Here we revisit the oldest part of the EDC CO2 record using different air extraction methods and sections of the core. For our established cracker system, we found an analytical artifact, which increases over the deepest 200 m and reaches 10.1 ± 2.4 ppm in the oldest/deepest part. The governing mechanism is not yet fully understood, but it is related to insufficient gas extraction in combination with ice relaxation during storage and ice structure. The corrected record presented here resolves partly ‐ but not completely ‐ the issue with a different correlation between CO2 and Antarctic temperatures found in this oldest part of the records. In addition, we provide here an update of 800,000 years atmospheric CO2 history including recent studies covering the last glacial cycle.
A new four‐plasma categorization scheme for the solar wind
Authors: Xu Fei , Borovsky Joseph E. 
Published: December 2014

AbstractA three‐parameter algebraic scheme is developed to categorize the solar wind at 1 AU into four plasma types: coronal‐hole‐origin plasma, streamer‐belt‐origin plasma, sector‐reversal‐region plasma, and ejecta. The three parameters are the proton‐specific entropy Sp = Tp/np2/3, the proton Alfvén speed vA, and the proton temperature Tp compared with a velocity‐dependent expected temperature. Four measurements are needed to apply the scheme: the proton number density np, the proton temperature Tp, the magnetic field strength B, and the solar wind speed vsw. The scheme is tested and is found to be more accurate than existing categorization schemes. The categorization scheme is applied to the 1963–2013 OMNI2 data set spanning four solar cycles and to the 1998–2008 ACE data set. The statistical properties of the four types of plasma are examined. The sector‐reversal‐region plasma is found to have statistically low alpha‐to‐proton density ratios and high Alfvén Mach numbers. The statistical relations between the proton and alpha‐particle‐specific entropies and oxygen and carbon charge‐state‐density ratios Sp, Sα, O7+/O6+, and C6+/C5+ from ACE are examined for the four types of plasma: the patterns observed imply a connection between sector‐reversal‐region plasma and ejecta and a connection between streamer‐belt‐origin plasma and coronal‐hole‐origin plasma. Plasma occurrence rates are examined and solar cycle patterns are found for ejecta, for coronal‐hole‐origin plasma, and for sector‐reversal‐region plasma.
X‐ray imaging of Kelvin‐Helmholtz waves at the magnetopause
Authors: Sun T. R. , Wang C. , Wei F. , Sembay S. 
Published: December 2014

AbstractThis paper simulates the Kelvin‐Helmholtz wave (KHW)‐induced X‐ray emissions at the low‐latitude magnetopause based on a global MHD code. A method is proposed to extract the KHW information from the X‐ray intensity measured by a hypothetical X‐ray telescope onboard a satellite assumed with a low Earth orbit. Specifically, the X‐ray intensity at high latitude is subtracted from the intensity map as a background to highlight the role of KHW. Using this method, global features of KHW such as the vortex velocity, perturbation degree, spatial distribution, and temporal evolution could be evaluated from the X‐ray intensity map. The validity of this method during intervals of solar wind disturbances is also verified. According to the simulation results, X‐ray imaging of KHW is suggested as a promising observation technique to essentially “see” the large‐scale configuration and evolution of KHW for the first time.
Impact of velocity correlation and distribution on transport in fractured media: Field evidence and theoretical model
Authors: Kang Peter K. , Le Borgne Tanguy , Dentz Marco , Bour Olivier , Juanes Ruben 
Published: December 2014

AbstractFlow and transport through fractured geologic media often leads to anomalous (non‐Fickian) transport behavior, the origin of which remains a matter of debate: whether it arises from variability in fracture permeability (velocity distribution), connectedness in the flow paths through fractures (velocity correlation), or interaction between fractures and matrix. Here we show that this uncertainty of distribution‐ versus correlation‐controlled transport can be resolved by combining convergent and push‐pull tracer tests because flow reversibility is strongly dependent on velocity correlation, whereas late‐time scaling of breakthrough curves is mainly controlled by velocity distribution. We build on this insight, and propose a Lagrangian statistical model that takes the form of a continuous time random walk (CTRW) with correlated particle velocities. In this framework, velocity distribution and velocity correlation are quantified by a Markov process of particle transition times that is characterized by a distribution function and a transition probability. Our transport model accurately captures the anomalous behavior in the breakthrough curves for both push‐pull and convergent flow geometries, with the same set of parameters. Thus, the proposed correlated CTRW modeling approach provides a simple yet powerful framework for characterizing the impact of velocity distribution and correlation on transport in fractured media.
Approximation Algorithms for Stochastic Optimization Problems in Operations Management
Authors: Shi Cong 
Published: December 2014

AbstractThis article provides an introduction to approximation algorithms in stochastic optimization models arising in various application domains, including central areas of operations management, such as scheduling, facility location, vehicle routing problems, inventory and supply chain management, and revenue management. Unfortunately, these models are very hard to solve to optimality in both theory and practice. We will survey recent development on approximation algorithms for these stochastic optimization models and their performance analysis techniques with worst‐case performance guarantees.
Rhodium(III)‐katalysierte Abfangcyclisierung zu vielfältigen 1‐Aminoindolinderivaten bei Raumtemperatur
Authors: Zhao Dongbing , Vásquez‐Céspedes Suhelen , Glorius Frank 
Published: December 2014

AbstractWir stellen eine RhIII‐katalysierte C‐H‐Aktivierung/Abfangcyclisierung vor, an der eine nukleophile Addition einer C(sp3)‐Rh‐Spezies an polarisierte Doppelbindungen beteiligt ist. Dies ist die erste intermolekulare katalytische Methode zur direkten Synthese von 1‐Aminoindolinen mit großer Substratbreite und unter milden Reaktionsbedingungen.
Total Synthesis of the Tiacumicin B (Lipiarmycin A3/Fidaxomicin) Aglycone
Authors: Glaus Florian , Altmann Karl‐Heinz 
Published: December 2014

AbstractTiacumicin B (lipiarmycin A3, fidaxomicin) is an atypical macrolide antibiotic which is used for the treatment of Clostridium difficile infections. Tiacumicin B is also a potent inhibitor of Mycobacterium tuberculosis, but due to its limited oral bioavailability is unsuitable for systemic therapy. To provide a basis for structure–activity studies that might eventually lead to improved variants of tiacumicin B, we have developed an efficient approach to the synthesis of the tiacumicin B aglycone. The synthesis features a high‐yielding intramolecular Suzuki cross‐coupling reaction to effect macrocyclic ring closure. Key steps in the synthesis of the macrocyclization precursor were a highly selective, one‐pot Corey–Peterson olefination and an ene–diene cross‐metathesis reaction. Depending on the reaction conditions, the final deprotection delivered either the fully deprotected tiacumicin B aglycone or partially protected versions thereof.
CO Extrusion in Homogeneous Gold Catalysis: Reactivity of Gold Acyl Species Generated through Water Addition to Gold Vinylidenes
Authors: Bucher Janina , Stößer Tim , Rudolph Matthias , Rominger Frank , Hashmi A. Stephen K. 
Published: December 2014

AbstractHerein, we describe a new gold‐catalyzed decarbonylative indene synthesis. Synergistic σ,π‐activation of diyne substrates leads to gold vinylidene intermediates, which upon addition of water are transformed into gold acyl species, a type of organogold compound hitherto only scarcely reported. The latter are shown to undergo extrusion of CO, an elementary step completely unknown for homogeneous gold catalysis. By tuning the electronic and steric properties of the starting diyne systems, this new reactivity could be exploited for the synthesis of indene derivatives in high yields.
Lupus Nephritis: Glycogen Synthase Kinase 3β Promotion of Renal Damage Through Activation of the NLRP3 Inflammasome in Lupus‐Prone Mice
Authors: Zhao Jijun , Wang Hongyue , Huang Yuefang , Zhang Hui , Wang Shuang , Gaskin Felicia , Yang Niansheng , Fu Shu Man 
Published: December 2014

ObjectiveGlycogen synthase kinase 3β (GSK‐3β) has been demonstrated to be involved in immune and inflammatory responses via multiple signaling pathways, leading to the production of proinflammatory cytokines. The purpose of this study was to investigate the role of GSK‐3β in the pathogenesis of lupus nephritis in 2 mouse models.MethodsThiadiazolidinone 8 (TDZD‐8), a selective inhibitor of GSK‐3β, was administered intraperitoneally to 12‐week‐old MRL/lpr mice for 8 weeks or to 22‐week‐old (NZB × NZW)F1 mice for 12 weeks. The expression of GSK‐3β and NLRP3 inflammasome components was analyzed. Proteinuria, biochemical parameters, proinflammatory cytokines, anti–double‐stranded DNA (anti‐dsDNA) antibody levels, and renal pathology were examined. In vitro, the effect of GSK‐3β–directed small interfering RNA (siRNA) on NLRP3 inflammasome activation was evaluated in bone marrow–derived macrophages (BMMs) from the mice and in the J774A.1 macrophage cell line.ResultsThe incidence of severe proteinuria and renal inflammation was significantly attenuated in both models, with a significant reduction in anti‐dsDNA antibody production, immune complex deposition in the kidney, and circulating proinflammatory cytokine levels. TDZD‐8 inhibited the activation of GSK‐3β and caspase 1, with a concomitant decrease in interleukin‐1β (IL‐1β) synthesis. In vitro, GSK‐3β siRNA transfection of mouse BMMs and the J774A.1 cell line with GSK‐3β siRNA inhibited the expression of GSK‐3β, the activation of caspase 1, and the production of IL‐1β.ConclusionThese results show that GSK‐3β promotes lupus nephritis at least partly by activating the NLRP3/IL‐1β pathway. The linking of GSK‐3β to the NLRP3/IL‐1β pathway is a novel observation in our study. Our results suggest that the GSK‐3β/NLRP3/IL‐1β pathway may be a potential therapeutic target for lupus in humans.
Synthesis of Heterocycles by Formal Cycloadditions of Isocyanides
Authors: Kruithof Art , Ruijter Eelco , Orru Romano V. A. 
Published: December 2014

AbstractSynthetic methodology for the synthesis of heterocycles is of continuous and high interest with applications in materials, catalysis, and medicines. Multicomponent reactions are suitable tools to efficiently generate chemically diverse sets of heterocycles with sufficient structural complexity. Especially isocyanides have proven to be particularly versatile building blocks in these one‐pot processes. Due to their electronic structure, isocyanides are able to act sequentially or simultaneously as a nucleophile and an electrophile. Traditionally, isocyanides are therefore frequently used in multicomponent chemistry. In the recent literature, numerous reactions have been reported that involve formal cycloadditions of isocyanides with conjugated heterodienes. This Focus Review aims at mapping this reactivity and at providing insight into the relationship between the various reported reaction partners and the observed reactivity modes.
Intelligent Integral Backstepping Sliding‐mode Control Using Recurrent Neural Network For Piezo‐flexural Nanopositioning Stage
Authors: Lin Faa‐Jeng , Lee Shih‐Yang , Chou Po‐Huan 
Published: December 2014

AbstractIn this study, an intelligent integral backstepping sliding‐mode control (IIBSMC) system using a recurrent neural network (RNN) is proposed for the three‐dimensional motion control of a piezo‐flexural nanopositioning stage (PFNS). First, the dynamic model of the PFNS is derived. Then, an integral backstepping sliding‐mode control (IBSMC) system is proposed for the tracking of the reference contours. The steady‐state response of the control system can be improved effectively due to the addition of the integrator in the IBSMC. Moreover, to relax the requirements of the bound and discard the switching function in the IBSMC, an IIBSMC system using an RNN estimator is proposed to improve the control performance and the robustness of the PFNS. The RNN estimator is proposed to estimate the lumped uncertainty, including the system parameters and external disturbance, online. Furthermore, the online tuning law for the training of the parameters of the RNN is derived using the Lyapunov stability theorem. In addition, a robust compensator is proposed to confront the minimum reconstructed error occurring in the IIBSMC system. Finally, some experimental results for the tracking of various contours are given to demonstrate the validity of the proposed IIBSMC system. From the performance measurements of the proportional‐integral control, sliding mode control, IBSMC, and IIBSMC systems, the proposed IIBSMC system has the lowest maximum, average, and standard deviation of the position tracking errors for three‐dimensional motion control of the PFNS.
Impacts of environmental humidity on concentric eyewall structure
Authors: Ge Xuyang 
Published: December 2014

AbstractThe tropical cyclone (TC) secondary eyewall (SE) is an important aspect of TC intensity and structure forecast, because it largely affects the horizontal scale of destructive winds and heavy rainfall. Hence, it is important to understand the possible factors that influence the structure and size of SE. Idealized simulations suggest that the environmental humidity is one of the key factors. It is favorable for TC to establish a SE in a moist environment. Furthermore, the SE is likely to be located at a larger radius, thereby leads to a wider moat area. Consequently, the structure of SE would affect TC intensity change during the eyewall replacement cycle. This study strongly motivates further researches with respect to how the environmental conditions influence the storm dynamics and thermodynamics.
Ectokinases as novel cancer markers and drug targets in cancer therapy
Authors: Yalak Garif , Vogel Viola 
Published: December 2014

AbstractWhile small‐molecule kinase inhibitors became the most prominent anticancer drugs, novel combinatorial strategies need to be developed as the fight against cancer is not yet won. We review emerging literature showing that the release of several ectokinases is significantly upregulated in body fluids from cancer patients and that they leave behind their unique signatures on extracellular matrix (ECM) proteins. Our analysis of proteomic data reveals that fibronectin is heavily phosphorylated in cancer tissues particularly within its growth factor binding sites and on domains that regulate fibrillogenesis. We are thus making the case that cancer is not only a disease of cells but also of the ECM. Targeting extracellular kinases or the extracellular signatures they leave behind might thus create novel opportunities in cancer diagnosis as well as new avenues to interfere with cancer progression and malignancy.
“Optimized” delivery of intracoronary supersaturated oxygen in acute anterior myocardial infarction: A feasibility and safety study
Authors: Hanson Ivan D. , David Shukri W. , Dixon Simon R. , Metzger D. Christopher , Généreux Philippe , Maehara Akiko , Xu Ke , Stone Gregg W. 
Published: December 2014

ObjectivesWe sought to evaluate the feasibility and safety of catheter‐based supersaturated oxygen (SSO2) delivery via the left main coronary artery (LMCA) following primary percutaneous coronary intervention (PCI). Background: In the multicenter, randomized AMIHOT‐II trial, SSO2 delivered into the proximal or mid left anterior descending (LAD) artery via an indwelling intracoronary infusion catheter in patients with acute anterior ST‐segment elevation myocardial infarction (STEMI) following primary PCI significantly reduced infarct size but resulted in a numerically higher incidence of safety events. Methods: Patients with acute anterior STEMI presenting within 6 hr of symptom onset were enrolled at three centers. Following successful LAD stenting, SSO2 was infused into the LMCA via a diagnostic catheter for 60 min. The primary safety endpoint was the 30‐day rate of target vessel failure (composite of death, reinfarction, or target vessel revascularization). Cardiac magnetic resonance imaging (cMRI) was performed at 3–5 and 30 days to assess infarct size. Results: Twenty patients with acute anterior STEMI were enrolled. The infarct lesion was located in the proximal LAD in 7 cases (35%) and the mid LAD in 13 cases (65%). Following primary PCI, SSO2 was delivered successfully in all cases. Target vessel failure within 30 days occurred in 1 patient (5%). Median [interquartile range] infarct size was 13.7% [5.4–20.6%] at 3–5 days and 9.6% [2.1–14.5%] at 30 days. Conclusions: Following primary PCI in acute anterior STEMI, infusion of SSO2 via the LMCA is feasible, and is associated with a favorable early safety and efficacy profile. © 2015 Wiley Periodicals, Inc.