3,953 research outputs found

    Magnetic behavior of lamellar mnps3 and cdps3 composites with a paramagnetic manganese(iii) macrocyclic guest

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    Indexación: ScieloSix new composites derived from the intercalation of the MPS3 phases (M = MnII, CdIII) with the macrocyclic manganese(III) complex [MnL(H2O)2].NO3(H2O) (LH2 = Schiff base macrocyclic ligand derived from the condensation of 2-hydroxy-5-methy1-1,3-benzene-dicarbaldehyde and 1,2-diamine-benzene) were obtained by two different synthetic procedures: a conventional and a microwave assisted method. The composites [MnL]0.25K0.15Mn0.80 PS3(H2O)~1.0 (1), and [MnL]0.25K0.15Cd 0. 80PS3(H2O)~0.5 (2) were obtained by the conventional method, after stirring a suspension of the corresponding potassium precursor and the macrocyclic complex for two weeks, while [MnL]0.35K0.15Mn0.80 PS3(H2O)~1.0 (3) and [MnL]0.25K0.15Cd 0. 80PS3(H2O)~0.5 (4) after stirring for four weeks at room temperature. Using a microwave assisted reaction permitted to obtain in a shorter period of time as compared with the conventional method, composites [MnL]0.20K0.15Mn0.80 PS3(H2O)~1.0 (5) and [MnL]0.15K0.15Cd 0. 80PS3(H2O)~0.5 (6). All the M = MnII, MnIII composites show a bulk antiferromagnetic behavior. However, the spontaneous magnetization present at low temperature in the potassium precursor K0.40Mn0.80 PS3(H2O)~1.0 is observable in composite [MnL]0.20K0.15Mn0.80 PS3(H2O)~1.0 (5), while it is completely absent in composites [MnL]0.25K0.15Mn0.80 PS3(H2O)~1.0 (1) and [MnL]0.35K0.15Mn0.80 PS3(H2O)~1.0 (3). Keywords: Intercalation; MPS3 phases; MnIII macrocyclic complex; microwave assisted synthesis; magnetic properties

    Comparación de pronósticos de caudales máximos con modelos ARIMA y redes neuronales artificiales

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    El presente estudio tuvo como principal objetivo comparar dos técnicas estadísticas de pronóstico  en el modelamiento del caudal máximo del río Huaura. La investigación fue de tipo aplicada y longitudinal porque se estudió el comportamiento de los caudales máximos del río Huaura a través del tiempo. Para cumplir con el objetivo se modeló la serie hidrológica mediante modelos ARIMA, donde 611 meses (90 %) de los datos se usó para ajuste del modelo y 68 meses (10 %), para  el pronóstico; y mediante redes neuronales artificiales autorregresivas (ARNN), donde 407 meses (60 %) de los datos se usó para entrenamiento, 204 meses (30 %), para prueba y 68 meses  (10 %), para reserva del modelo. Finalmente se encontró que el modelo ARNN es más eficiente que los modelos ARIMA para realizar pronósticos

    Factores asociados al rendimiento académico de estudiantes de Ingeniería Estadística, Universidad Nacional de Trujillo, 2019

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    El objetivo de la investigación se centró en determinar factores asociados al rendimiento académico, para ello, se usó un diseño no experimental, transversal y descriptivo. Se utilizóla técnica de muestreo aleatorio irrestricto para determinar el tamaño de muestra, dando como  resultado 19 y 15 estudiantes de II Y IV ciclo respectivamente. Las técnicas estadísticas empleadas, utilizando el software R-Studio, fueron: la Selección de Clústeres para la clasificación de variables, donde se determinó 4 clúster denominados: Nivel educativo más alto entre los padres del estudiante, Factores Sociodemográficos, Medio de traslado a la universidad y Factores de distancia  y responsabilidad académica; y el Análisis Factorial de Correspondencias Múltiples determinándose el perfil de los estudiantes con promedio ponderado de mayor frecuencia, comprendido de 11 a 14, el cual se caracteriza por: su conformación de grupos que es heterogénea, sexo femenino, no presentan cursos rezagados, su medio de traslado es el transporte público, viven en Trujillo Metropolitano y tienen una edad mayor o igual a 20 años

    Critical rotation of a harmonically trapped Bose gas

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    We study experimentally and theoretically a cold trapped Bose gas under critical rotation, i.e. with a rotation frequency close to the frequency of the radial confinement. We identify two regimes: the regime of explosion where the cloud expands to infinity in one direction, and the regime where the condensate spirals out of the trap as a rigid body. The former is realized for a dilute cloud, and the latter for a Bose-Einstein condensate with the interparticle interaction exceeding a critical value. This constitutes a novel system in which repulsive interactions help in maintaining particles together.Comment: 4 pages, 4 figures, submitted to PR

    Identification of circulating miRNA profiles that distinguish malignant pleural mesothelioma from lung adenocarcinoma

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    Accurate diagnosis of malignant pleura mesothelioma (MPM) is challenging. Differential diagnosis of MPM versus lung adenocarcinoma (AD) is particularly difficult, yet clinically important since the two neoplasias call for different treatment approaches. Circulating miRNA-profiling to identify miRNAs that can be used to distinguish MPM from AD has not been reported. We conducted a wide screening study of miRNA profiles in serum pools of MPM patients (N = 11), AD patients (N = 36), and healthy subjects (N = 45) to identify non-invasive biomarkers for differential diagnosis of MPM and AD, using deep sequencing. Sequencing detected up to 300 known miRNAs and up to 25 novel miRNAs species in the serum samples. Among known miRNAs, 7 were upregulated in MPM and 12 were upregulated in AD compared to healthy controls. Of these, eight were distinctive for AD and three were unique for MPM. Direct comparison of the miRNA profiles for MPM and AD revealed differences in miRNA levels that could be useful for differential diagnosis. No differentially expressed novel miRNAs were found. Further bioinformatics analysis indicated that three upregulated miRNAs in MPM are associated with the p38 pathway. There are unique alterations in serum miRNAs in MPM and AD compared to healthy controls, as well as differences between MPM and AD profiles. Differing miRNA levels between MPM and AD may be useful for differential diagnosis. A potential association to p38 pathway of three upregulated miRNAs in MPM was revealed

    Continuous Matrix Product Ansatz for the One-Dimensional Bose Gas with Point Interaction

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    We study a matrix product representation of the Bethe ansatz state for the Lieb-Linger model describing the one-dimensional Bose gas with delta-function interaction. We first construct eigenstates of the discretized model in the form of matrix product states using the algebraic Bethe ansatz. Continuous matrix product states are then exactly obtained in the continuum limit with a finite number of particles. The factorizing FF-matrices in the lattice model are indispensable for the continuous matrix product states and lead to a marked reduction from the original bosonic system with infinite degrees of freedom to the five-vertex model.Comment: 5 pages, 1 figur

    Active wetting of epithelial tissues

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    Development, regeneration and cancer involve drastic transitions in tissue morphology. In analogy with the behavior of inert fluids, some of these transitions have been interpreted as wetting transitions. The validity and scope of this analogy are unclear, however, because the active cellular forces that drive tissue wetting have been neither measured nor theoretically accounted for. Here we show that the transition between 2D epithelial monolayers and 3D spheroidal aggregates can be understood as an active wetting transition whose physics differs fundamentally from that of passive wetting phenomena. By combining an active polar fluid model with measurements of physical forces as a function of tissue size, contractility, cell-cell and cell-substrate adhesion, and substrate stiffness, we show that the wetting transition results from the competition between traction forces and contractile intercellular stresses. This competition defines a new intrinsic lengthscale that gives rise to a critical size for the wetting transition in tissues, a striking feature that has no counterpart in classical wetting. Finally, we show that active shape fluctuations are dynamically amplified during tissue dewetting. Overall, we conclude that tissue spreading constitutes a prominent example of active wetting --- a novel physical scenario that may explain morphological transitions during tissue morphogenesis and tumor progression

    Collective modes of a quasi two-dimensional Bose condensate in large gas parameter regime

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    We have theoretically studied the collective modes of a quasi two-dimensional (Q2D) Bose condensate in the large gas parameter regime by using a formalism which treats the interaction energy beyond the mean-field approximation. In the calculation we use the perturbative expansion for the interaction energy by incorporating the Lee, Huang and Yang (LHY) correction term. The results show that incorporation of this higher order term leads to detectable modifications in the mode frequencies.Comment: 10 pages, 2 figure

    Dynamically Driven Evolution of the Interstellar Medium in M51

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    We report the highest-fidelity observations of the spiral galaxy M51 in CO emission, revealing the evolution of giant molecular clouds (GMCs) vis-a-vis the large-scale galactic structure and dynamics. The most massive GMCs (so-called GMAs) are first assembled and then broken up as the gas flow through the spiral arms. The GMAs and their H2 molecules are not fully dissociated into atomic gas as predicted in stellar feedback scenarios, but are fragmented into smaller GMCs upon leaving the spiral arms. The remnants of GMAs are detected as the chains of GMCs that emerge from the spiral arms into interarm regions. The kinematic shear within the spiral arms is sufficient to unbind the GMAs against self-gravity. We conclude that the evolution of GMCs is driven by large-scale galactic dynamics --their coagulation into GMAs is due to spiral arm streaming motions upon entering the arms, followed by fragmentation due to shear as they leave the arms on the downstream side. In M51, the majority of the gas remains molecular from arm entry through the inter-arm region and into the next spiral arm passage.Comment: 6 pages, including 3 figures. Accepted, ApJ
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