Do we really know the prevalence of accomodative and nonstrabismic binocular dysfunctions?

Purpose: To determine the scientific evidence about the prevalence of accommodative and nonstrabismic binocular anomalies. Methods: We carried out a systematic review of studies published between 1986 and 2009, analysing the MEDLINE, CINAHL, FRANCIS and PsycINFO databases. We considered admitting those papers related to prevalence in paediatric and adult populations. We identified 660 articles and 10 papers met the inclusion criteria. Results: There is a wide range of prevalence, particularly for accommodative insufficiency (2 %-61.7 %) and convergence insufficiency (2.25 %-33 %). More studies are available for children (7) compared with adults (3). Most of studies examine clinical population (5 studies) with 3 assessed at schools and 1 at University with samples that vary from 65 to 2048 patients. There is great variability regarding the number of diagnostic signs ranging from 1 to 5 clinical signs. We found a relation between the number of clinical signs used and prevalence values for convergence insufficiency although this relationship cannot be confirmed for other conditions. Conclusion: There is a lack of proper epidemiological studies about the prevalence of accommodative and nonstrabismic binocular anomalies. Studies reviewed examine consecutive or selected patients in clinical settings and schools but in any case they are randomized and representative of their populations with no data for general population. The wide discrepancies in prevalence figures are due to both sample population and the lack of uniformity in diagnostic criteria so that it makes difficult to compile results. Biases and limitations of reports determine that prevalence rates offered are only estimations from selected populations.

Análisis relacional sobre el grado de credibilidad entre diferentes medios de comunicación en materia de drogas

Antecedentes: En la actualidad los medios de comunicación se constituyen como la principal fuente de información de la que se nutren los jóvenes. No obstante, y pese a la gran cantidad y variedad de mensajes disponibles, la información no siempre se construye adecuadamente debido a las frecuentes discrepancias con las que los medios de comunicación suelen exponerla. En referencia al tratamiento informativo que los diversos medios confieren a temas relacionados con la salud en general, y de forma más concreta sobre temas referentes a las drogas, es muy frecuente que la percepción tienda hacia un sensacionalismo exacerbado y una gran descontextualización de la información, lo que incide negativamente en la credibilidad que se otorga a los diversos medios. Metodología: En este estudio piloto se analiza la relación existente entre el grado de credibilidad que los jóvenes encuestados conceden a los distintos medios de comunicación, tanto si se refiere a información en general como si se refiere a temas sobre drogas. De igual modo, se indaga la relación existente entre el grado de información objetivo que poseen los sujetos sobre las distintas sustancias y la percepción del tratamiento que los medios de comunicación dan a la información sobre drogas. Para ello, participaron en el estudio 115 alumnos (27% varones y 73% mujeres) de primero de grado en Psicología, de la Universidad Miguel Hernández de Elche (Alicante-España). Conclusiones: Los resultados muestran correlaciones positivas del grado de credibilidad otorgado a los diversos medios, tanto si se trata sobre temas de información general como sobre temas relacionados con las drogas. Por otra parte, los jóvenes mantienen diferentes percepciones sobre el tratamiento que realizan los medios de comunicación de las noticias y contenidos sobre drogas, en función del nivel de información objetivo que poseen de las distintas sustancias de abuso.

La nueva Estadística de Migraciones: una buena elección por parte del INE

El Instituto Nacional de Estadística ha decidido elaborar una nueva Estadística de Migraciones utilizando como base la Estadística de Variaciones Residenciales. En este artículo se aportan algunos argumentos que apoyan esta decisión, ante la persistente falta de coherencia entre las fuentes del sistema estadístico español para captar la movilidad. En particular, se profundiza en los problemas de subestimación e inconsistencia interna de la Encuesta de Población Activa para medir la inmigración, a la vista de las diferencias entre las tres series de flujos de inmigración internacional que es posible estimar a partir de la misma.

Isothermal (liquid + liquid) equilibrium data at T = 313.15 K and isobaric (vapor + liquid + liquid) equilibrium data at 101.3 kPa for the ternary system (water + 1-butanol + p-xylene)

The (vapor + liquid), (liquid + liquid) and (vapor + liquid + liquid) equilibria of the ternary system (water + 1-butanol + p-xylene) have been determined. (Water + 1-butanol + p-xylene) is a type 2 heterogeneous ternary system with partially miscible (water + 1-butanol) and (water + p-xylene) pairs. By contrast, (1-butanol + p-xylene) is totally miscible under atmospheric conditions. This paper examines the (vapor + liquid) equilibrium in both heterogeneous and homogeneous regions at 101.3 kPa of pressure. (Liquid + liquid) equilibrium data at T = 313.15 K have also been determined, and for comparison, the obtained experimental data have been calculated by means of several thermodynamic models: UNIQUAC, UNIFAC and NRTL. Some discrepancies were found between the (vapor + liquid + liquid) correlations; however, the models reproduced the (liquid + liquid) equilibrium data well. The obtained data reveal a ternary heterogeneous azeotrope with mole fraction composition: 0.686 water, 0.146 1-butanol and 0.168 p-xylene.

Detection and mapping of burnt areas from time series of MODIS-derived NDVI data in a Mediterranean region

Moderate resolution remote sensing data, as provided by MODIS, can be used to detect and map active or past wildfires from daily records of suitable combinations of reflectance bands. The objective of the present work was to develop and test simple algorithms and variations for automatic or semiautomatic detection of burnt areas from time series data of MODIS biweekly vegetation indices for a Mediterranean region. MODIS-derived NDVI 250m time series data for the Valencia region, East Spain, were subjected to a two-step process for the detection of candidate burnt areas, and the results compared with available fire event records from the Valencia Regional Government. For each pixel and date in the data series, a model was fitted to both the previous and posterior time series data. Combining drops between two consecutive points and 1-year average drops, we used discrepancies or jumps between the pre and post models to identify seed pixels, and then delimitated fire scars for each potential wildfire using an extension algorithm from the seed pixels. The resulting maps of the detected burnt areas showed a very good agreement with the perimeters registered in the database of fire records used as reference. Overall accuracies and indices of agreement were very high, and omission and commission errors were similar or lower than in previous studies that used automatic or semiautomatic fire scar detection based on remote sensing. This supports the effectiveness of the method for detecting and mapping burnt areas in the Mediterranean region.

Preliminary interpretation of shaking-table response of a full-scale 3-storey building composed of thin reinforced concrete sandwich walls

In the last few decades, the use of cast in situ reinforced concrete sandwich panels for the construction of low- to mid-rise buildings has become more and more widespread due to several interesting properties of this construction technique, such as fast construction and high thermal and acoustic performances. Nonetheless the level of knowledge of the structural behavior of systems made of squat reinforced concrete sandwich panels is still not so consolidated, especially with reference to the seismic response, due to the lack of experimental studies. In recent years, while various experimental tests have been conducted on single panels aimed at assessing their seismic capacity, only few tests have been carried out on more complex structural systems. In this paper, the experimental results of a series of shaking-table tests performed on a full-scale 3-storey building are presented in detail. The main goal is to give to the scientific community the possibility of develop independent interpretation of these experimental results. An in-depth interpretation of the discrepancies between the analytical predictions and the experimental results is beyond the objective of this paper and is still under development. Nonetheless, preliminary interpretations indicate that both the stiffness and the strength of the building under dynamic excitation appear quite superior with respect to those expected from the results of previous pseudo-static cyclic tests conducted on simple specimens.