The role of approximate negators in modeling the automatic detection of negation in tweets

Although improvements have been made in the performance of sentiment analysis tools, the automatic detection of negated text (which affects negative sentiment prediction) still presents challenges. More research is needed on new forms of negation beyond prototypical negation cues such as “not” or “never.” The present research reports findings on the role of a set of words called “approximate negators,” namely “barely,” “hardly,” “rarely,” “scarcely,” and “seldom,” which, in specific occasions (such as attached to a word from the non-affirmative adverb “any” family), can operationalize negation styles not yet explored. Using a corpus of 6,500 tweets, human annotation allowed for the identification of 17 recurrent usages of these words as negatives (such as “very seldom”) which, along with findings from the literature, helped engineer specific features that guided a machine learning classifier in predicting negated tweets. The machine learning experiments also modeled negation scope (i.e. in which specific words are negated in the text) by employing lexical and dependency graph information. Promising results included F1 values for negation detection ranging from 0.71 to 0.89 and scope detection from 0.79 to 0.88. Future work will be directed to the application of these findings in automatic sentiment classification, further exploration of patterns in data (such as part-of-speech recurrences for these new types of negation), and the investigation of sarcasm, formal language, and exaggeration as themes that emerged from observations during corpus annotation

Arbitrage-Free Bond Pricing with Dynamic Macroeconomic Models

We examine the relationship between monetary-policy-induced changes in short interest rates and yields on long-maturity default-free bonds. The volatility of the long end of the term structure and its relationship with monetary policy are puzzling from the perspective of simple structural macroeconomic models. We explore whether richer models of risk premiums, specifically stochastic volatility models combined with Epstein-Zin recursive utility, can account for such patterns. We study the properties of the yield curve when inflation is an exogenous process and compare this to the yield curve when inflation is endogenous and determined through an interest-rate/Taylor rule. When inflation is exogenous, it is difficult to match the shape of the historical average yield curve. Capturing its upward slope is especially difficult as the nominal pricing kernel with exogenous inflation does not exhibit any negative autocorrelation - a necessary condition for an upward sloping yield curve as shown in Backus and Zin (1994). Endogenizing inflation provides a substantially better fit of the historical yield curve as the Taylor rule provides additional flexibility in introducing negative autocorrelation into the nominal pricing kernel. Additionally, endogenous inflation provides for a flatter term structure of yield volatilities which better fits historical bond data.

Arbitrage-free bond pricing with dynamic macroeconomic models

The authors examine the relationship between changes in short-term interest rates induced by monetary policy and the yields on long-maturity default-free bonds. The volatility of the long end of the term structure and its relationship with monetary policy are puzzling from the perspective of simple structural macroeconomic models. The authors explore whether richer models of risk premiums, specifically stochastic volatility models combined with Epstein-Zin recursive utility, can account for such patterns. They study the properties of the yield curve when inflation is an exogenous process and compare this with the yield curve when inflation is endogenous and determined through an interest rate (Taylor) rule. When inflation is exogenous, it is difficult to match the shape of the historical average yield curve. Capturing its upward slope is especially difficult because the nominal pricing kernel with exogenous inflation does not exhibit any negative autocorrelation-a necessary condition for an upward-sloping yield curve, as shown in Backus and Zin. Endogenizing inflation provides a substantially better fit of the historical yield curve because the Taylor rule provides additional flexibility in introducing negative autocorrelation into the nominal pricing kernel. Additionally, endogenous inflation provides for a flatter term structure of yield volatilities, which better fits historical bond data.Bonds - Prices ; Macroeconomics

CARCINOMA INDIFERENCIADO CON CÉLULAS GIGANTES DE TIPO OSTEOCLASTOS EN LA CABEZA DE PÁNCREAS: UNDIFFERENTIATED CARCINOMA WITH OSTEOCLAST-LIKE GIANT CELLS (UC-OGC) OF THE HEAD OF PANCREAS

Undifferentiated carcinoma with undifferentiated osteoclast-like cells (UC-OGC) in the head of the pancreas is extremely rare. The clinicalpathological, imaging and topographic appearance characteristics are not wellclassified. This case report describes a patient with UC-OGC of the Pancreas Head. Our patient, an adult over 75 years of age, had a considerable illness time, without relevant symptoms until the advanced stages of the tumor, debuting with shallow gastric discomfort, then weight loss. In the diagnostic tests they found the presence of a tumor that compromised the stomach, duodenum and pancreas. The definitive diagnosis was given by the pathological study. There are not enough clinical data available for a treatment that guarantees a higher survival rate in patients, however, pancreatoduodenectomy is currently the alternative that offers the best results, on the other hand, the prognosis after surgery and the recurrence rate still uncertain.El carcinoma indiferenciado con células indiferenciadas tipo osteoclasto (UC-OGC) en cabeza de páncreas, es extremadamente raro. Las características clínicopatológicas, de imagen y la apariencia topográfica no están bien clasificadas. Este reporte de caso describe un paciente con UC-OGC de cabeza de páncreas. Nuestro paciente un adulto mayor de 75 años de edad, presentaba un tiempo de enfermedad considerable, sin sintomatología relevante hasta las etapas avanzadas del tumor, debutando con molestias gástricas someras, luego pérdida de peso. En los exámenes diagnósticos hallaron la presencia de un tumor que comprometía el estómago, duodeno y páncreas. El diagnóstico definitivo lo dio el estudio anatomopatológico. No se dispone de datos clínicos suficientes para un tratamiento que garantice una mayor tasa de supervivencia en los pacientes, sin embargo, la pancreatoduodenectomía es actualmente la alternativa que mejores resultados ofrece, por otra parte, el pronóstico después de la cirugía y la tasa de recurrencia sigue incierto

Luminescent and Scintillating Properties of Lanthanum Fluoride Nanocrystals in Response to Gamma/Neutron Irradiation: Codoping with Ce Activator, Yb Wavelength Shifter, and Gd Neutron Captor

A novel concept for detection and spectroscopy of gamma rays, and detection of thermal neutrons based on codoped lanthanum fluoride nanocrystals containing gadolinium is presented.The trends of colloidal synthesis of the mentioned material, LaF3 co-doped with Ce as the activator, Yb as the wavelength-shifter and Gd as the neutron captor, is reported. Nanocrystals of the mentioned material were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), optical absorption, and photoluminescence spectroscopy. Gamma detection and its potential spectroscopy feature have been confirmed. The neutron detection capability has been confirmed by experiments performed using a 252Cf neutron source.Comment: 5 figures, 16 page

Van der Waals torque induced by external magnetic fields

We present a method for inducing and controlling van der Waals torques between two parallel slabs using a constant magnetic field. The torque is calculated using the Barash theory of dispersive torques. In III-IV semiconductors such as $InSb$, the effect of an external magnetic field is to induce an optical anisotropy, in an otherwise isotropic material, that will in turn induce a torque. The calculations of the torque are done in the Voigt configuration, with the magnetic field parallel to the surface of the slabs. As a case study we consider a slab made of calcite and a second slab made of $InSb$. In the absence of magnetic field there is no torque. As the magnetic field increases, the optical anisotropy of $InSb$ increases and the torque becomes different from zero, increasing with the magnetic field. The resulting torque is of the same order of magnitude as that calculated using permanent anisotropic materials when the magnetic fields is close to 1 T.Comment: to appear in Journal of Applied Physic

Thermoluminescent Characteristics of Li2B4O7 Doped with Mn2+ and Eu3+ Ions

Analysis of thermoluminescent properties were made for two samples; Li2B4O7, Li2B4O7:Mn2+:Eu3+. These samples were prepared by melt quenching method. The glow curves of the samples show two broad peaks at 160º C and 245 ºC, and a high peak at 130ºC for Li2B4O7 doped. The response of the materials were analyzed according to the doses (0.2-80 Gy), fading (0-72 hours) and reproducibility of the experiment (10 times). To determine how the glow curve is formed, thermal bleaching for a dose of 5 Gy were made from room temperature to 300º C. Besides, X-ray diffraction patterns were recorded to identify the structure and grain size of the samples

Clima organizacional y desempeño docente en instituciones educativas de la Unidad Gestión Educativa Local, Huánuco - 2017

Objective. To determine the relationship between the organizational climate and the performance of the teacher in the educational institutions of secondary level of the Local Educational Management Unit of Huánuco, in the year 2017. Methods. The study was a quantitative approach, applied, of a correlational descriptive type, with 86 teachers selected by simple random probability sampling, who answered an interview and two scales: one of the organizational climate and another of teacher performance, previously validated and reliable. The ethical considerations of the research were applied. Spearman's Rho test was used in inferential analysis for p ≤ 0.05. Results. A moderate, direct, positive and significant relationship was established between the dimensions of the organizational climate: the teaching environment, conflict management, leadership, social relationships and emotional balance with teacher performance (rs = 0.45, rs = 0.45, rs = 0.44, rs = 0.42 and rs = 0.42 respectively) (p <0.05). It was the low positive, direct and significant correlation between the following dimensions: level of communication and managerial style with teaching performance (rs = 0.35 and rs = 0.33 with p ≤ 0.05), so the null hypotheses were rejected. Conclusions. There is a direct, positive and significant relationship at a moderate level between the organizational climate and teaching performance in the Educational Institutions of the UGEL Huánuco during 2017 (rs = 0.44 and p <0.05). And it is assumed that while the organizational climate becomes favorable, too; the good performance of teachers is increased.Objetivo. Determinar la relación entre el clima organizacional y el desempeño del docente en las instituciones educativas de nivel secundario de la Unidad Gestión Educativa Local de Huánuco, en el año 2017. Métodos. El estudio fue de enfoque cuantitativo, aplicada, de tipo descriptivo correlacional con 86 docentes seleccionados por muestreo probabilístico aleatorio simple, quienes respondieron una entrevista y dos escalas: una del clima organizacional y otra de desempeño docente, previamente validados y fiabilizados. Se aplicaron las consideraciones éticas de la investigación. En el análisis inferencial se utilizó la prueba Rho de Spearman para un p ≤ 0,05. Resultados. Se estableció relación moderada, directa, positiva y significativa entre las dimensiones del clima organizacional: el ambiente docente, manejo de conflictos, liderazgo, relaciones sociales y equilibrio emocional con el desempeño docente (rs = 0,45, rs = 0,45, rs = 0,44, rs = 0,42 y rs = 0,42 respectivamente) (p < 0,05). Fue la correlación baja positiva, directa y significativa entre las siguientes dimensiones: nivel de comunicación y estilo gerencial con el desempeño docente (rs = 0,35 y rs = 0, 33 con p ≤ 0,05), por lo que se rechazaron las hipótesis nulas. Conclusiones. Existe relación directa, positiva y significativa de nivel moderado entre el clima organizacional y el desempeño docente en las Instituciones Educativas de la UGEL Huánuco durante el 2017 (rs = 0,44 y p < 0,05). Entonces se asume que mientras el clima organizacional se torna favorable, también; se incrementa el buen desempeño de los docentes

Predicción de comportamiento crediticio

Este trabajo se centra en mejorar la evaluación del riesgo crediticio utilizando el conjunto de datos South German Credit. El objetivo principal es seleccionar el mejor modelo de clasificación entre Regresión Logística, Support Vector Machine (SVM), Árboles Aleatorios y Árboles de Decisión para predecir si un cliente es "bueno" o "malo" en términos de crédito. Los objetivos específicos del trabajo son describir el conjunto de datos, encontrar el mejor modelo de clasificación utilizando el Accuracy como métrica principal. En el desarrollo del trabajo, se realiza una descripción detallada del conjunto de datos, incluyendo su origen, tamaño, atributos y objetivo. También se justifica la elección de los cuatro modelos de clasificación mencionados y se describe brevemente cada uno de ellos. Se realiza un análisis de correlación para identificar las relaciones entre las variables del conjunto de datos y su influencia en el riesgo crediticio. Se destaca qué variables, como la duración del crédito, el monto del crédito, la edad del solicitante y la tasa de interés, tienen correlación con el riesgo crediticio. Se opta por utilizar todas las variables del conjunto de datos. Se resalta la importancia de la medida de Accuracy para evaluar el rendimiento de los modelos de clasificación en este problema y se presentan los resultados obtenidos en siete experimentos. Los principales cambios entre los experimentos fueron los tratamientos de las variables categóricas, utilizando principalmente LabelEncoder y OneHotEncoder para evitar una jerarquización falsa. Se presentan las Accuracy obtenidas para cada modelo en todos los experimentos y se selecciona el mejor de ellos. El mejor modelo fue el SVM con grid search para la afinación de los hiperparámetos, con lo cual se obtuvo un Accuracy de 83.92%