Cross Section Measurements of Deuteron Electro-Disintegration at Very High Recoil Momenta and Large 4-Momentum Transfers (Q2)

The 2H(e,e′p)n cross sections have been measured at negative 4-momentum transfers of Q2 = 4.5±0.5 (GeV/c)2 and Q2 = 3.5±0.5 (GeV/c)2 reaching neutron recoil (missing) momenta up to pr ∼1.0 GeV/c. The data have been obtained at fixed neutron recoil angles 5o ≤ θnq ≤ 95o with respect to the 3-momentum transfer q. The new data agree well with the previous data which reached pr ∼ 500 MeV/c. At θnq = 35o and 45o, final state interactions (FSI), meson exchange currents (MEC) and isobar configurations (IC) are suppressed and the plane wave impulse approximation (PWIA) provides the dominant cross section contribution. The new data are compared to recent theoretical calculations, and a significant disagreement for recoil momenta pr \u3e 700 MeV/c is observed. The experiment was carried out in experimental Hall C at the Thomas Jefferson National Accelerator Facility (TJNAF) and formed part of a group of four experiments that were used to commission the new Super High Momentum Spectrometer (SHMS). The experiment consisted of a 10.6 GeV electron beam incident on a liquid deuterium target which resulted in the break-up of the deuteron into a proton and neutron. The scattered electrons were detected by the SHMS in coincidence with the knocked-out protons detected in the previously existing High Momentum Spectrometer (HMS) and the recoiling neutrons were reconstructed from energy-momentum conservation laws. To ensure that the 2H(e,e′p)n reaction channel was selected, we required the missing energy of the system to be the binding energy of the deuteron (∼2.22 MeV). The spectrometers’ central angles and momenta were set to measure three central missing momentum settings of the neutron corresponding to pr = 80, 580 and 750 MeV/c which required the SHMS central angle and momentum to be fixed and the HMS to be rotated from smaller to larger angles corresponding to the lower and higher missing momentum settings, respectively. The experiment was carried out in a time period of six days with typical electron beam currents of 45-60 μA at about 50% beam efficiency

Construcción de un octógono con sus vértices en los lados de un cuadrado: ejemplos y consideraciones didácticas

Objective: The paper discloses cardinal requirements for the selection and elaboration of geometric problems and didactic considerations for their treatment with the assistance of GeoGebra. Methods: The authors rely on theoretical and empirical methods to review oral, written and visual sources, in particular in senior high school mathematics school texts, methodological guidelines and scientific articles addressing geometric problem solving. Result: The main finding is the description of nine requirements of particular importance for geometric problem solving. Related didactic ideas are explained by devising problems of a different nature as compare to those generally included senior high school texts. Conclusion: The demands described and the didactic ideas presented by means of problems constitute important theoretical and practical references of a general nature for the selection, elaboration and didactic treatment of geometric problems.Objetivo: Revelar exigencias cardinales para la selección y elaboración de problemas geométricos y consideraciones didácticas para su tratamiento con asistencia del GeoGebra. Métodos: Se emplearon métodos teóricos y empíricos que permitieron profundizar en fuentes orales, escritas y visuales, de manera particular en los textos escolares de matemática para la enseñanza media, orientaciones metodológicas y artículos científicos que abordan problemas geométricos. Resultado: La precisión de nueve exigencias de particular importancia para problemas geométricos y consideraciones didácticas que se explican a partir de problemas que se distinguen de los que generalmente aparecen en textos escolares y abordan en la enseñanza media. Conclusión: Las exigencias reveladas y las consideraciones didácticas expuestas mediante problemas constituyen importantes referentes teóricos y prácticos de carácter general para la selección, elaboración y tratamiento didáctico de problemas geométricos

La obtención de información. ¿Habilidad académica, informativa o investigativa? / Finding information. Academic, informative, or research skill?

El presente artículo tiene el propósito de exponer los resultados alcanzados hasta la fecha de un estudio que se está llevando a cabo concerniente a la formación y desarrollo de la habilidad obtener información científica. En el mismo se advierte sobre la necesidad e importancia de la temática en la era de la información y el conocimiento. Se realiza un análisis de las tendencias actuales a nivel global sobre las habilidades en el manejo y uso de la información científica, a partir de sus regularidades y discrepancias, sobre la base de las cuales se define la habilidad obtener información científica y se ofrece el sistema operacional cuyo dominio conduce a su desarrollo.AbstractThis paper is intended to describe the results of a study of training the ability to obtain scientific data. The need and importance of the topic, in the era of the information and the knowledge, is backed up. Global current tendencies on the abilities in the handling and use of the scientific information are reviewed on the basis of regularities and inconsistencies. This leads to define the ability and its corresponding operational system

La formación de competencias informacionales en el ingeniero industrial / Industrial engineer information literacy training

El artículo describe las propiedades estadísticas de la información, su importancia para la toma de decisiones y la necesidad incluir la alfabetización informacional como parte del proceso de enseñanza aprendizaje en las universidades. El objetivo de la investigación fue proponer acciones que lograran integrar los procesos de solución de problemas docentes y la búsqueda, evaluación y recuperación de la información que requiere su solución. Se emplearon como métodos el análisis documental y la sistematización teórica para la construcción de los fundamentos conceptuales que se proponen, la modelación de su estructura y componentes. Finalmente se aplicó un pre-experimento pedagógico para evaluar la efectividad de la propuesta desde la formación del ingeniero industrial en la Universidad de Camagüey. El resultado esencial de la investigación estuvo en las acciones propuestas, como síntesis de la solución de problemas docentes y de información, que posibilitaron las transformaciones operadas en el comportamiento informacional de los estudiantes.ABSTRACTThe article describes the characteristics of information, its importance for making of decisions and the need of including information literacy as a focus of the teaching-learning process at the university. The aim was to devise activities capable of integrating academic solving problem and locating, accessing and retrieving the information needed for their corresponding solution. A theoretical framework is constructed on the basis of documents analysis and systematizing methods, modeling was used to devise the activities describing their structure and components. Finally, an experiment was carried out to evaluate the effectiveness of the proposal in training industrial engineers at the University of Camagüey. The findings include a set of activities that combines problem-solving with information management which in terms lead to improving students’ ability and informational behavior

The effects of lasers on bond strength to ceramic materials: A systematic review and meta-analysis

Lasers have recently been introduced as an alternative means of conditioning dental ceramic surfaces in order to enhance their adhesive strength to cements and other materials. The present systematic review and meta-analysis aimed to review and quantitatively analyze the available literature in order to determine which bond protocols and laser types are the most effective. A search was conducted in the Pubmed, Embase and Scopus databases for papers published up to April 2017. PRISMA guidelines for systematic review and meta-analysis were followed. Fifty-two papers were eligible for inclusion in the review. Twenty-five studies were synthesized quantitatively. Lasers were found to increase bond strength of ceramic surfaces to resin cements and composites when compared with control specimens (p-value < 0.01), whereas no significant differences were found in comparison with air-particle abraded surfaces. High variability can be observed in adhesion values between different analyses, pointing to a need to standardize study protocols and to determine the optimal parameters for each laser type

Diffraction-Based Phase Calibration of Spatial Light Modulators With Binary Phase Fresnel Lenses

We propose a simple and robust method to determine the calibration function of phase-only spatial light modulators (SLMs). The proposed method is based on the codification of binary phase Fresnel lenses (BPFLs) onto an SLM. At the principal focal plane of a BPFL, the focal irradiance is collected with a single device just able to measure intensity-dependent signals, e.g., CCD camera, photodiodes, power meter, etc. In accordance with the theoretical model, it is easy to extract the desired calibration function from the numerical processing of the experimental data. The lack of an interferometric optical arrangement, and the use of minimal optical components allow a fast alignment of the setup, which is in fact poorly dependent on environmental fluctuations. In addition, the effects of the zero-order, commonly presented in the diffraction-based methods, are drastically reduced because measurements are carried out only in the vicinity of the focal points, where main light contributions are coming from diffracted light at the BPFL. Furthermore, owing to the simplicity of the method, full calibration can be done, in most practical situations, without moving the SLM from the original place for a given application.This work was supported in part from MINECO under Grant FIS2013–40666-P, Generalitat Valenciana under Grants PROMETEO2012–021 and ISIC 2012/013, and Universitat Jaume I (P1-1B2012-55)

El Apóstol: A 1900 de altura sobre lo conocido

One of the most emotionally significant and symbolic transcendence events that has taken place, as a tribute to Marti in the homeland of his adoration, in commemorating the centenary of his birth, has been the placement by the Association of Alumni of the Marti Seminary, a bust to the Apostle, in the top of the more high mountain: the Turquino Peak. The present work has the objective of characterizing the facts related to the placement of the bust of José Marti at the top of the Turquino Peak, the relevance that was for the architects of this tribute and its consequent significance for the current generations. The piece of bronze of 163 pounds of the national main character, every day at sunrise, receives its violet rays that give light and vigor to his forehead.Uno de los actos de más emotiva significación y trascendencia simbólica que se han celebrado, como homenaje a Martí en la patria de sus adoraciones, al conmemorarse el centenario de su nacimiento, ha sido la colocación por la Asociación de Antiguos Alumnos del Seminario Martiano, de un busto al Apóstol, en la cima de la más alta montaña: el Pico Turquino. El presente trabajo tiene el objetivo de caracterizar los hechos relacionados con la colocación del busto de José Martí en la cima del Pico Turquino, la relevancia que revistió para los artífices de este homenaje y su consecuente significación para las generaciones actuales. La pieza de bronce de 163 libras del Héroe Nacional, todos los días al salir el sol, recibe  sus rayos violetas que le dan luz y vigor a su frente