Riesgo de hipertensión arterial por ruido laboral: revisión sistemática

Introducción: la pérdida auditiva inducida por ruido es el efecto nocivo del ruido más comúnmente estudiado, sin embargo, el ruido también produce trastornos digestivos y del sueño, cambios en los niveles de cortisol, efectos cardiovasculares e hipertensión arterial (HTA), entre otros. Objetivo: determinar si la exposición laboral a ruido induce hipertensión arterial. Materiales y métodos: se siguieron las recomendaciones del método PRISMA para revisiones sistemáticas. Se hizo una búsqueda de estudios en PUBMED utilizando los términos “occupational and noise and hypertension” y aplicando los filtros: 1) publicaciones incluidas entre 2005-2015; 2) estudios publicados en inglés; 3) revisión de títulos y resúmenes; 4) revisión completa de los textos para un total final de 32 estudios. Se hizo la revisión, análisis y resumen de todos los estudios. Resultados: los estudios concluyeron que aquellos portadores de los polimorfismos de la enzima convertidora de angiotensina expuestos a ruido, tuvieron una mayor susceptibilidad genética a tener HTA. Los estudios reportaron una asociación positiva entre ruido e HTA. Hay controversia acerca de la relación que existe entre HTA, ruido y coexposición a otros factores como calor, trabajo por turnos, presencia de solventes o plomo en el lugar de trabajo y carga física. Conclusiones: Se presume que solo los niveles de ruido ≥ 85 dBA tienen efectos negativos sobre la salud, pero se ha encontrado que los efectos no auditivos del ruido se producen por debajo de este parámetro. Recomendaciones: se sugiere el uso de la pérdida auditiva inducida por ruido entre población trabajadora como un método de tamizaje para detectar personas prehipertensas, con el fin prevenir la generación de HTA.

Eficacia de la estimulación magnética transcraneal en la disminución de severidad en el trastorno depresivo mayor en monoterapia y coadyuvante comparado con tratamientos farmacológicos. Revisión sistemática y meta-análisis

Resumen Introducción Una posible opción de tratamiento para el manejo del trastorno depresivo mayor (TDM) es la estimulación magnética transcraneal (EMT) que ha mostrado propiedades antidepresivas superiores al placebo con un buen perfil de seguridad. El objetivo del presente trabajo es determinar la reducción en la severidad del TDM y la proporción de eventos adversos (EA) en pacientes con TDM refractario y no refractario, posterior al uso de EMT administrada en monoterapia o tratamiento coadyuvante comparado con terapia farmacológica. Metodología Se planteó una pregunta PICOT de la cual se realizó una búsqueda sistemática de estudios clínicos en las bases de datos Medline, EMBASE y Cochrane. Dos investigadores en forma independiente realizaron la selección de artículos, evaluación de calidad con la herramienta de la colaboración Cochrane y extracción de datos. Se extrajeron datos de eficacia como tasa de respuesta, porcentaje de remisión, calidad de vida, diminución sintomática del trastorno depresivo mayor en la escala de Hamilton y capacidad funcional. Igualmente, proporción de pacientes con EA. Se realizó un meta-análisis de estas variables teniendo en cuenta la heterogeneidad. Resultados La presente revisión sistemática incluyó 26 estudios clínicos aleatorizados de baja calidad metodológica mostrando que la EMT presentó una eficacia superior cuando es usada como coadyuvante a las terapias con que venían siendo tratados los pacientes con TDM refractario y no refractario en los desenlaces de tasa de respuesta y porcentaje de remisión. En el caso de intervenciones farmacológicas específicas, la EMT presento eficacia similar, tanto en terapia coadyuvante como en monoterapia comparado con las intervenciones farmacológicas. En cuanto a seguridad, la EMT presenta un buen perfil de seguridad debido a que en todos los escenarios estudiados los EA fueron no serios y baja frecuencia Conclusiones La evidencia disponible sugiere que la EMT mostró ser efectivo y seguro para el manejo del TDM refractario y no refractario. Sin embargo, la evidencia es débil por lo tanto se necesita mayor investigación clínica que soporte su uso.

Eye movements of beginning and more skilled readers

The present study aimed to analyze and compare the eye movements of beginning (2nd grade) and more skilled (4th grade) readers, during reading words and pseudo-words aloud, that differ in frequency (just for words), regularity and length. In this way, one intends to analyze the process of visual information extraction, by both groups, and detect experience and practice-related changes in the ocular behavior. The eye movements of 34 children were monitored, while these were reading words/pseudo-words lists, and this was accomplished using eye-tracking technology. The results show statistically significant differences between the two groups, in mean and total fixations duration for high-frequency words, in mean fixation duration for regular words and in the mean saccade amplitude in irregular pseudo-words. However, no significant differences were found between the groups on the study of the other variables. Nevertheless, the results suggest that skilled readers tend to show more effective eye movements, what determined a lesser effect of words’ frequency, regularity and length on this group. Moreover, the pseudo-words processing was more difficult than that of words, in both groups.

Auditory speech-discrimination as a function of age and type of audiogram

This paper reviews a study to determine if loss of speech discrimination is related to age and patients with audiograms showing steep high-frequency losses.

Recognition of temporarily modified speech stimuli

This paper studies the relationship between consonant duration and recognition of these consanants by listeners with high frequency hearing loss.

Sociodemographic and nutritional correlates of neurobehavioral development: a study of young children in a rural region of Ecuador

To identify and describe the sociodemographic and nutritional characteristics associated with neurobehavioral development among young children living in three communities in the northeastern Andean region of Cayambe-Tabacundo, Ecuador. Women in the study communities who had a child 3 to 61 months of age completed a questionnaire about maternal and child health and sociodemographic characteristics. The Ages and Stages Questionnaire (ASQ) was directly administered to 283 children by two trained interviewers. Growth measurements and a hemoglobin finger-prick blood test were obtained in 2003–2004. Prevalence of developmental delay was calculated, and associations between child development and maternal, child, and household characteristics were explored. High frequencies of developmental delay were observed. Children 3 to 23 months old displayed delay in gross motor skills (30.1%), and children 48 to 61 months old displayed delay in problem-solving skills (73.4%) and fine motor skills (28.1%). A high frequency of both anemia (60.4%) and stunting (53.4%) was observed for all age groups. Maternal educational level was positively associated with communication and problem-solving skills, and monthly household income was positively associated with communication, gross motor, and problem-solving skills. The results suggest a high prevalence of developmental delay and poor child health in this population. Child health status and the child’s environment may contribute to developmental delay in this region of Ecuador, but sociodemographic factors affecting opportunities for stimulation may also play a role. Research is needed to identify what is causing high percentages of neurobehavioral developmental delay in this region of Ecuador.

Efficient evaluation of highly oscillatory acoustic scattering surface integrals

We consider the approximation of some highly oscillatory weakly singular surface integrals, arising from boundary integral methods with smooth global basis functions for solving problems of high frequency acoustic scattering by three-dimensional convex obstacles, described globally in spherical coordinates. As the frequency of the incident wave increases, the performance of standard quadrature schemes deteriorates. Naive application of asymptotic schemes also fails due to the weak singularity. We propose here a new scheme based on a combination of an asymptotic approach and exact treatment of singularities in an appropriate coordinate system. For the case of a spherical scatterer we demonstrate via error analysis and numerical results that, provided the observation point is sufficiently far from the shadow boundary, a high level of accuracy can be achieved with a minimal computational cost.

Analysis of convectively-generated gravity waves in mesoscale model simulations and wind profiler observations

The characteristics of convectively-generated gravity waves during an episode of deep convection near the coast of Wales are examined in both high resolution mesoscale simulations [with the (UK) Met Oce Unified Model] and in observations from a Mesosphere-Stratosphere-Troposphere (MST) wind profiling Doppler radar. Deep convection reached the tropopause and generated vertically propagating, high frequency waves in the lower stratosphere that produced vertical velocity perturbations O(1 m/s). Wavelet analysis is applied in order to determine the characteristic periods and wavelengths of the waves. In both the simulations and observations, the wavelet spectra contain several distinct preferred scales indicated by multiple spectral peaks. The peaks are most pronounced in the horizontal spectra at several wavelengths less than 50 km. Although these peaks are most clear and of largest amplitude in the highest resolution simulations (with 1 km horizontal grid length), they are also evident in coarser simulations (with 4 km horizontal grid length). Peaks also exist in the vertical and temporal spectra (between approximately 2.5 and 4.5 km, and 10 to 30 minutes, respectively) with good agreement between simulation and observation. Two-dimensional (wavenumber-frequency) spectra demonstrate that each of the selected horizontal scales contains peaks at each of preferred temporal scales revealed by the one- dimensional spectra alone.

Pleistocene geochronologies for fluvial sedimentary sequences: an archaeologist's perspective

Current models of Pleistocene fluvial system development and dynamics are assessed from the perspective of European Lower and Middle Palaeolithic stone tool assemblages recovered from fluvial secondary contexts. Fluvial activity is reviewed both in terms of Milankovitch-scale processes across the glacial/interglacial cycles of the Middle and Late Pleistocene, and in response to sub-Milankovitch scale, high-frequency, low-magnitude climatic oscillations. The chronological magnitude of individual phases of fluvial activity is explored in terms of radiocarbon-dated sequences from the Late Glacial and early Holocene periods. It is apparent that fluvial activity is associated with periods of climatic transition, both high and low magnitude, although system response is far more universal in the case of the high magnitude glacial/ interglacial transitions. Current geochronological tools do not permit the development of high-resolution sequences for Middle Pleistocene sediments, while localised erosion and variable system responses do not facilitate direct comparison with the ice core records. However, Late Glacial and early Holocene sequences indicate that individual fluvial activity phases are relatively brief in duration (e.g. 10(2) and 10(3) yr). From an archaeological perspective, secondary context assemblages can only be interpreted in terms of a floating geochronology, although the data also permit a reinvestigation of the problems of artefact reworking. Copyright (c) 2005 John Wiley I Sons, Ltd.

Doppler lidar measurements of oriented planar ice crystals falling from supercooled and glaciated layer clouds

The properties of planar ice crystals settling horizontally have been investigated using a vertically pointing Doppler lidar. Strong specular reflections were observed from their oriented basal facets, identified by comparison with a second lidar pointing 4° from zenith. Analysis of 17 months of continuous high-resolution observations reveals that these pristine crystals are frequently observed in ice falling from mid-level mixed-phase layer clouds (85% of the time for layers at −15 °C). Detailed analysis of a case study indicates that the crystals are nucleated and grow rapidly within the supercooled layer, then fall out, forming well-defined layers of specular reflection. From the lidar alone the fraction of oriented crystals cannot be quantified, but polarimetric radar measurements confirmed that a substantial fraction of the crystal population was well oriented. As the crystals fall into subsaturated air, specular reflection is observed to switch off as the crystal faces become rounded and lose their faceted structure. Specular reflection in ice falling from supercooled layers colder than −22 °C was also observed, but this was much less pronounced than at warmer temperatures: we suggest that in cold clouds it is the small droplets in the distribution that freeze into plates and produce specular reflection, whilst larger droplets freeze into complex polycrystals. The lidar Doppler measurements show that typical fall speeds for the oriented crystals are ≈ 0.3 m s−1, with a weak temperature correlation; the corresponding Reynolds number is Re ∼ 10, in agreement with light-pillar measurements. Coincident Doppler radar observations show no correlation between the specular enhancement and the eddy dissipation rate, indicating that turbulence does not control crystal orientation in these clouds. Copyright © 2010 Royal Meteorological Society

A double data rate (DDR) architecture for OFDM based wireless consumer devices

The creation of OFDM based Wireless Personal Area Networks (WPANs) has allowed the development of high bit-rate wireless communication devices suitable for streaming High Definition video between consumer products, as demonstrated in Wireless-USB and Wireless-HDMI. However, these devices need high frequency clock rates, particularly for the OFDM, FFT and symbol processing sections resulting in high silicon cost and high electrical power. The high clock rates make hardware prototyping difficult and verification is therefore very important but costly. Acknowledging that electrical power in wireless consumer devices is more critical than the number of implemented logic gates, this paper presents a Double Data Rate (DDR) architecture for implementation inside a OFDM baseband codec in order to reduce the high frequency clock rates by a complete factor of 2. The presented architecture has been implemented and tested for ECMA-368 (Wireless- USB context) resulting in a maximum clock rate of 264MHz instead of the expected 528MHz clock rate existing anywhere on the baseband codec die.

Risk factors for tick attachment to smallholder dairy cattle in Tanzania

A cross-sectional study was conducted in Tanga and Iringa regions of Tanzania, and a longitudinal study in Tanga, to investigate tick-control methods and other factors influencing tick attachment to the cattle of smallholder dairy farms. Most farmers reported applying acaricides at intervals of 1-2 weeks, most used acaricides that require on-farm dilution and most farmers incorrectly diluted the acaricides. Rhipicephalus appendiculatus and Boophilus spp. ticks were those most-frequently encountered on the cattle, but few cattle carried ticks of any species (only 13 and 4.6% of tick counts of the cattle yielded adult R. appendiculatus and Boophilus spp., respectively). Animals were more likely to carry one or more adult Boophilus spp. ticks if they also carried one or more R. appendiculatus adults (OR = 14.4, CI = 9.2, 22.5). The use of pour-on acaricides was associated with lower odds that animals carried a R. appendiculatus tick (OR = 0.29, CI = 0. 18, 0.49) but higher odds that they carried a Boophilus spp. tick (OR = 2.48, CI = 1.55, 3.97). Animals > 4 months old and those with a recent history of grazing had higher odds of carrying either a R. appendiculatus (ORs = 3.41 and 2.58, CIs = 2.34, 4.98 and 1.80, 3.71), or a Boophilus spp. tick (ORs = 5.70 and 2.18, CIs = 2.34, 4.98 and 1.49. 3.25), but zero-grazing management did not prevent ticks attaching to cattle even when combined with high-frequency acaricide treatments. The odds that animals carried ticks varied amongst the agro-ecological zones (AEZs) and administrative districts where the farms were situated-but there was still considerable residual variation in tick infestation at the farm level. (c) 2004 Elsevier B.V. All rights reserved.

Chemical characterisation of wild populations of Thymus from different climatic regions in southeast Spain

Thymus is taxonomically a very complex genus with a high frequency of hybridisation and introgression among sympatric species. The variation in accumulation of leaf-surface flavonoids was investigated in 71 wild populations of Thymus front different putative hybrid swarm areas in Andalucia, Spain. Twenty-two flavones, five flavanones, two dihydroflavonols, a flavonol and two unknowns were detected by HPLC-DAD combined with LC-APCI-MS analysis. The majority of compounds were flavones with a lutelin-type substitution of the B-ring, in contrast to previous reports on Macedonian taxa, which predominantly accumulate flavones with apigenin-type substitution of the B-ring. Anatomical and morphometric studies, supported by cluster analysis, identified pure Thymus hyemalis and Thymus baeticus populations, and a large number of putative hybrids. Flavonoid variation was closely related to morphological variation in all populations and is suspected to be a result of genetic polymorphism. Principal component analysis identified the presence of species-specific and geographically linked chemotypes and putative hybrids with mixed morphological and chemical characteristics. Qualitative and quantitative flavonoid accumulation appears to be genetically regulated, while external factors play a secondary role. Flavonoid profiles can thus provide diagnostic markers for the taxonomy of Thymus and are also useful in detecting hybridising taxa. (C) 2007 Elsevier Ltd. All rights reserved.

Transmission of cocoa swollen shoot virus by seeds

A study was undertaken to determine whether cocoa swollen shoot virus is transmitted by seeds, to improve the robustness of quarantine procedures for international exchange and long term conservation of cocoa germplasm. PCR/capillary electrophoresis, using cocoa swollen shoot virus primers designed from the most conserved regions of the six published cocoa genome sequences, allowed the detection of cocoa swollen shoot virus in all the component parts of cocoa seeds from cocoa swollen shoot virus-infected trees. PCR/capillary electrophoresis revealed the presence of cocoa swollen shoot virus in seedlings raised from seeds obtained from cocoa swollen shoot virus-infected trees. The high frequency with which the virus was transmitted through the seedlings suggested that cocoa swollen shoot virus is transmitted by seeds. This has serious implications for cocoa germplasm conservation and distribution. (C) 2008 Elsevier B.V. All rights reserved.

Stocking may increase mitochondrial DNA diversity but fails to halt the decline of endangered Atlantic salmon populations

Over the last 50 years, Spanish Atlantic salmon (Salmo salar) populations have been in decline. In order to bolster these populations, rivers were stocked with fish of northern European origin during the period 1974-1996, probably also introducing the furunculosis-inducing pathogen, Aeromonas salmonicida. Here we assess the relative importance of processes influencing mitochondrial (mt)DNA variability in these populations from 1948 to 2002. Genetic material collected over this period from four rivers in northern Spain (Cantabria) was used to detect variability at the mtDNA ND1 gene. Before stocking, a single haplotype was found at high frequency (0.980). Following stocking, haplotype diversity (h) increased in all rivers (mean h before stocking was 0.041, and 0.245 afterwards). These increases were due principally to the dramatic increase in frequency of a previously very low frequency haplotype, reported at higher frequencies in northern European populations proximate to those used to stock Cantabrian rivers. Genetic structuring increased after stocking: among-river differentiation was low before stocking (1950s/1960s Phi(ST) = -0.00296-0.00284), increasing considerably at the height of stocking (1980s Phi(ST) = 0.18932) and decreasing post-stocking (1990s/2002 Phi(ST) = 0.04934-0.03852). Gene flow from stocked fish therefore seems to have had a substantial role in increasing mtDNA variability. Additionally, we found significant differentiation between individuals that had probably died from infectious disease and apparently healthy, angled fish, suggesting a possible role for pathogen-driven selection of mtDNA variation. Our results suggest that stocking with non-native fish may increase genetic diversity in the short term, but may not reverse population declines.