Luminescence Dating of Beach Dunes and Fluvial Sediments, Nayarit, Mexico

The Pacific coast of the state of Nayarit, Mexico, is dominated by extensive sand dune systems and lagoons. 16 samples from three transects through dunes near the town of Santa Cruz were collected to establish ages of the beach dune ridges and establish a robust chronology, to assist in understanding the depositional rates associated with different phases of the evolution of the strand plain. In addition, three samples were collected from a fluvial terrace on the San Pedro River which enters the Pacific near the southernmost of the dune transects. Quartz grains were extracted from the samples, and analysed using an Optically Stimulated Luminescence (OSL) method to determine stored dose and ages. The samples collected nearest the current coast have produced dates of 1500-1900AD, with samples further from the coast being progressively older, spanning a period of over 2000 years with oldest measured date of 400BC. The dates for the upper samples from the San Pedro River is consistent with the ages of the dunes nearest the coast, with the lower sample date closer to the dates of the older dunes further from the coast, indicating that this fluvial deposit was laid down over the same time period as the dune formation

Using three different approaches of OSL for the study of young fluvial sediments at the coastal plain of the Usumacinta–Grijalva River Basin, southern Mexico

We use three different approaches of optically stimulated luminescence (OSL) to study young fluvial sediments located at the main channels of one of the largest fluvial systems of North America: the Usumacinta–Grijalva. We use the pulsed photo-stimulated luminescence (PPSL) system also known as portable OSL reader, full OSL dating and profiling OSL dating in samples extracted from vertical sediment profiles (n = 9) of riverbanks to detect changes in depositional rates of sediments and to obtain the age of the deposits. The results of the PPSL system show that the luminescence signals of vertical sediment profiles highly scattered from the top to the bottom contrast with the luminescence pattern observed on well-reset sequences of fluvial deposits where luminescence increase from the top to the bottom of the profile. The profiling and full OSL ages yielded large uncertainty values on their ages. Based on the inconsistencies observed in both ages and luminescence patterns of profiles we suggest that these fluvial deposits were not fully reset during their transport. As an explanation, we propose that in the Usumacinta and Grijalva rivers the cyclonic storms during the wet season promote the entrainment of large volumes of sediments due to high-erosional episodes around the basin resulting from hyper-concentrated and turbid flows. We conclude that the PPSL, profiling and full OSL dating of sediments are useful tools to quantify and to assess the depositional patterns in fluvial settings during the Holocene. These techniques also can yield information about sites where increases in the sediment load of rivers may produce poorly resetting of grains affecting the results of OSL dating

OSL Characterisation of Two Fluvial Sequences of the River Usmacinta in its Middle Catchment (SE Mexico)

The report summarizes luminescence profiling, initially using a SUERC PPSL system in Mexico, and laboratory analysis at SUERC, used to characterise the stratigraphy and interpret sedimentary processes in terrace deposits of the Usumacinta River, SE Mexico. This was then followed, by quantitative quartz OSL SAR dating of five sediment samples, aimed at defining the chronologicalframework of two sedimentary sequences, USU13-1 and USU13-2. In the wider region, the middle catchment of the Usumacinta River, contains numerous archaeological sites dating to the Maya Classic Period, including Bonampak, Yaxchilan and Piedras Negras. The broader aim of the investigation is to assess whether the two fluvial sequences contain a proxy record of environmental change through the archaeological period of interest. Initial luminescence profiling revealed that the stratigraphy in each profile was complex, reflecting multiple cycles of deposition, with signal maxima, followed by tails to lower intensities, possibly indicating deposition during extreme flood events, interleaved with periods of slower sedimentation, and potentially better luminescence resetting. Laboratory profiling reproduced the apparent maxima/trends in the field profiling dataset, confirming that both sections record complex depositional histories. Furthermore, the variations in stored dose estimates, and luminescence sensitivities with depth, confirm that the sections do not record simple age-depth progressions. Quantitative quartz OSL SAR dating was undertaken on five sediment samples. Given the information obtained from the field- and laboratory-profiles it is not surprising that the equivalent dose distributions for each sample showed considerable scatter, particularly so for the second section, USU13-2. Nevertheless, throughstatistical analysis, individual quartz OSL SAR ages were obtained for each sample. Individual dates fall into the Mayan Post-Classical Period to early modern Period, with statistical combinations pointing to a late 15th century accumulation of USU13-1, and the 18th century accumulation of the sediment within USU13-2. Interestingly, the three samples from section USU13-2, all show some aliquots which tail to higher equivalent doses; furthermore, in each sample, the mean value determined for this component is similar, suggesting that the sediment sampled in USU13-2, may be sourced from a 15th century or older accumulation upstream

Estudio topografico(mejoramiento vial y ampliación pista Rubenia-Lozelsa)

El siguiente trabajo consiste en la realización de un estudio topográfico de 2.32 km para la ampliación de la pista Solidaridad que abarca desde Rubenia hasta la Rotonda Loselza en la ciudad de Managua departamento de Managua. Este documento fue estructurado de la siguiente manera para poder facilitar el trabajo y comprensión del estudio topográfico: Primeramente se realizo un cronograma de trabajo para conocer el tiempo de finalización del estudio topográfico; en donde se calculo un tiempo de 52 días hábiles. (Ver anexos pág. #72) Seguidamente este documento reflejara el procedimiento exacto de cómo realizar un levantamiento topográfico según los procedimientos y estándares de la DIRECCION GENERAL DE PROYECTO de la alcaldía de Managua (ver pág. #12). También incluirá los equipos usados en campo( tipos y calidad),memoria de cálculo de poligonal, banqueo de niveles, planimetría, altimetría y perfiles longitudinales correspondientes a la área donde se efectuara dicho mejoramiento y ampliación. Finalmente se presentaran los resultados de este estudio las conclusiones y recomendaciones para mejorar el trabajo de campo que es lo principal para un estudio topográfico además anexos donde se muestran los planos topográficos y fotografías del trabajo de campo realizad

Molecularly imprinted silica films prepared by electroassisted deposition for the selective detection of dopamine

Dopamine (DA) can be detected by electrochemical oxidation in conventional electrodes. However, the presence of other oxidizable species (interferents) usually present in physiological fluids at high concentrations (like ascorbic acid) makes very difficult its electrochemical detection. In the present work, glassy carbon electrodes have been modified with molecularly imprinted silica (MIS) films prepared by electroassisted deposition of sol–gel precursors. The production of MIS films was performed by adding the template molecule (DA) to the precursor sol. The molecular impression of silica was assessed showing a high coherency allowing a filtering capacity in the molecular scale. The MIS-modified electrodes present a high selectivity for the detection of DA in neutral or acidic solutions. The MIS-modified electrodes allow the amperometric determination of dopamine in solutions containing ascorbic acid with molar ratios lower than 1:50,000.We acknowledge the financial support from the Fundación Ramón Areces (CIVP16A1821), Spanish Ministerio de Economía y Competitividad (MAT2013-42007-P) and Generalitat Valenciana (PROMETEO2013/038)

Aplicacion del modelo de evaluacion por puntos con fines retributivos : el caso de Ex-Isapre Compensacion S.A.

133 p.En estos últimos diez anos el país ha enfrentado múltiples cambios, los cuales han afectado en mayor medida a las Empresas de Servicios, obligándolas a incorpo-rar nuevas tecnologías que les permitan mantener los niveles deseados de rentabili-dad. Es por este motivo, que han tratado de aprovechar las economías de escala que les ofrece la integración y la expansión de sus respectivos giros. Esta agresiva competencia ha traspasado la lucha por el consumidor, manifestándose además, en el reclutamiento y mantención del personal. Motivo por el cual los administradores deben recurrir, cada vez con mayor frecuencia, a la utilización de técnicas que permitan mejorar la calidad de las relaciones internas. Es por esto, que el presente estudio muestra como alternativa viable, la aplicación del Método de Evaluación por Puntos como una herramienta teórica que permite definir una Estructura Salarial competitiva. La aplicación del MEP se Ilevó a cabo en Isapre Compensación S.A., comen-zando con la etapa de "Análisis del Puesto de Trabajo", en la que se empleo el método Delphi para clasificar en Niveles las Familias de Cargos existentes, según grado de importancia para la organización. En la etapa de "Descripción de Cargos", a través de un cuestionario, se determine en los diferentes niveles, la presencia de 17 Factores de Especificación', que serán la base de la "Evaluación de Cargos", en la cual se asigno un valor' a estos, según el grado de presencia de los factores e im-portancia relativa. En la etapa "Retributiva", se presento las Estructuras Salariales de la Empresa y de Mercado, utilizando el método "Mid Point". De la investigación se puede concluir y proponer lo siguiente: 1) Compensación utiliza políticas discrecionales para definir sus niveles de rentas. 2) Una posible Estructura Salarial para Isapre Compensación. 3) Se estimo el monto en pesos que debería destinarse para Ilevar a los empleados dentro de los márgenes de la posible estructura salarial propuesta

Proceso de producción para la exportación de café de calidad al mercado internacional por parte de la empresa CISA Exportadora en el período 2014-2015

El presente estudio analiza el proceso de producción de café de calidad para el diseño de una estrategia que mejore la capacidad de exportación de la empresa CISA Exportadora a mercados internacionales periodo 2014-2015. Esta investigación es de tipo cualitativo se trabajó en la empresa CISA Exportadora, con sede central en Managua y sus cuatro oficinas regionales de Ocotal, Matagalpa, Jinotepe y Jinotega. Se utilizaron entrevistas, guía de observación y una encuesta dirigida a los productores. Una sugerencia es impulsar programas para la integración de nuevos productores y asesorías técnicas para incrementar sus sellos de calidad

Fibropapilomatosis oral múltiple como manifestación inicial de Síndrome de Cowden: caso clínico

El síndrome de Cowden es una infrecuente enfermedad hereditaria englobada dentro de las poliposis gastrointestinales de tipo hamartomatoso. Se caracteriza por asociar anomalías cutaneomucosas y por la extraordinaria tendencia a desarrollar neoplasias malignas, principalmente de mama y tiroides. La importancia de un diagnóstico precoz del síndrome y de un adecuado screening tumoral en pacientes con lesiones papilomatosas cutaneomucosas, nos va a permitir adelantarnos en el diagnóstico de patologías con enorme morbimortalidad asociada en caso de una detección tardía. Presentamos el caso de una paciente diagnosticada de síndrome de Cowden tras consultar por lesiones papilomatosas labiales de largo tiempo de evolución y tratada posteriormente de cáncer de mama y riñón en estadios iniciales. El correcto diagnóstico de una patología banal de mucosa oral, nos ha permitido actuar de manera muy precoz frente a la patología neoplásica asociada a dicha enfermedad.Cowden syndrome is a rare hereditary disease included within hamartoma-type gastrointestinal polyposis. It is characterised by associated mucocutaneous anomalies and by the extraordinary tendency to develop malignant neoplasia, mainly in the breast and thyroid. Early diagnosis of the syndrome and adequate tumoral screening in patients with mucocutaneous papillomatosis make it possible to make an earlier diagnosis of associated pathologies which have great morbidity when detected late. We present the case of a patient diagnosed with Cowden syndrome after consultation for labial papillomatous lesions of long evolution who was subsequently treated for breast and kidney cancer in initial stages. The correct diagnosis of a banal pathology of oral mucosa made it possible for us to take early action against the neoplastic pathology associated with this disease

A general perspective of the characterization and quantification of nanoparticles: Imaging, spectroscopic, and separation techniques

This article gives an overview of the different techniques used to identify, characterize, and quantify engineered nanoparticles (ENPs). The state-of-the-art of the field is summarized, and the different characterization techniques have been grouped according to the information they can provide. In addition, some selected applications are highlighted for each technique. The classification of the techniques has been carried out according to the main physical and chemical properties of the nanoparticles such as morphology, size, polydispersity characteristics, structural information, and elemental composition. Microscopy techniques including optical, electron and X-ray microscopy, and separation techniques with and without hyphenated detection systems are discussed. For each of these groups, a brief description of the techniques, specific features, and concepts, as well as several examples, are described.Junta de Andalucía FQM-5974CEI-Biotic Granada CEI2013- MP-1