1,500 research outputs found
Derivation of a multilayer approach to model suspended sediment transport: application to hyperpycnal and hypopycnal plumes
We propose a multi-layer approach to simulate hyperpycnal and hypopycnal
plumes in flows with free surface. The model allows to compute the vertical
profile of the horizontal and the vertical components of the velocity of the
fluid flow. The model can describe as well the vertical profile of the sediment
concentration and the velocity components of each one of the sediment species
that form the turbidity current. To do so, it takes into account the settling
velocity of the particles and their interaction with the fluid. This allows to
better describe the phenomena than a single layer approach. It is in better
agreement with the physics of the problem and gives promising results. The
numerical simulation is carried out by rewriting the multi-layer approach in a
compact formulation, which corresponds to a system with non-conservative
products, and using path-conservative numerical scheme. Numerical results are
presented in order to show the potential of the model
The IACOB project. VI. On the elusive detection of massive O-type stars close to the ZAMS
The apparent lack of massive O-type stars near the zero-age main sequence (at
ages < 2 Myr) is a topic widely discussed. Different explanations for this
elusive detection have been proposed, but no firm conclusions have been reached
yet. We reassess this empirical result benefiting from the high-quality
spectroscopic observations of >400 Galactic O-type stars gathered by the IACOB
and OWN surveys. We used temperatures and gravities from a iacob-gbat/fastwind
spectroscopic analysis to locate our sample in the Kiel and spectroscopic HR
diagrams. We evaluated the completeness of our sample of stars, observational
biases using information from the Galactic O star catalog (GOSC), systematics
of our methodology, and compare with other recent studies using smaller samples
of Galactic O-type stars. We base our discussion on the spectroscopic HR
diagram to avoid the use of uncertain distances. We performed a detailed study
of the young cluster Trumpler-14 as an example of how Gaia cluster distances
can help to construct the associated classical HR diagram. The apparent lack of
massive O-type stars near the ZAMS with masses between 30 and 70 Msol persist
even when spectroscopic results from a large, non-biased sample of stars are
used. We do not find correlation between the dearth of stars and observational
biases, limitations of our methodology, or the use of spectroscopic HR diagram
instead of the classical one. Investigating the efficiency of mass accretion
during the formation process we conclude that an adjustment of the accretion
rate towards lower values could reconcile the hotter boundary of detected
O-type stars and the theoretical birthline. Last, we discuss that the presence
of a small sample of O2-O3.5 stars found closer to the ZAMS might be explained
taking into account non-standard star evolution (e.g. binary interaction,
mergers, or homogeneous evolution).Comment: 20 pages, 15 figures, accepted for publication in Astronomy &
Astrophysic
Evaluation of two toothbrushes prescriptions on the removal of plaque in patients with fixed orthodontic appliances
Indexación: Web of Science; ScieloLa aparatología empleada en los tratamientos de ortodoncia, favorece la retención de placa bacteriana y dificulta su eliminación por parte del paciente, aumentando el riesgo de desarrollar caries, manchas blancas y enfermedad periodontal. Diferentes cepillos dentales se han desarrollado para facilitar la mantención de una adecuada higiene oral en estos pacientes, sin embargo, se ha observado que los cepillos comunmente indicados (cepillo ortodóncico mas cepillo unipenacho), no siempre son bien manejados y difícilmente se usan ambos. El cepillo Cross Action Pro-Salud®, se ha presentado como una alternativa simple de usar y de transportar, por ser un único cepillo que combina las caracteristicas de los dos cepillos comunmente recomendados. Para evaluar la efectividad de este cepillo, en comparación con la prescripción convencional, se evaluaron 2 grupos, de 23 pacientes cada uno, portadores de aparatología fija. Un grupo utilizó la prescripción habitual y un segundo grupo utilizó cepillo Cross Action Pro-Salud®, por un período de 45 días. Los indices de higiene de O`leary, de placa en brackets y gingival modificado fueron registrados al inicio y 45 días después del uso diario de los cepillos antes mencionados. Se utilizó test-t para comparar los resultados obtenidos y se determinó que se produjo una disminución significativa en los tres indices de higiene, no existiendo diferencias en los resultados obtenidos entre ambas prescripciones. El cepillo Oral-B Cross-Action Pro-Salud® es una alternativa recomendable, ya que permite eliminar efectivamente la placa bacteriana en pacientes ortodónticos, y al ser un único cepillo, facilita y acorta el tiempo de cepillado.Orthodontic fixed appliances include elements that allow the accumulation of bacterial plaque, making tooth brushing more difficult and increasing the risk of developing caries, white spot lesions, and periodontal disease. Several toothbrushes designs have been developed to facilitate oral hygiene in orthodontic patients; however, it has been observed that most patients do not take enough time to brush using adequately both commonly prescribed toothbrushes (Oral-B End-Tufted® and Oral-B Orthodontic® brushes). Oral B Cross Action Pro-Health® has been presented as an alternative, easier to use and to transport. To assess the effectiveness of Cross Action Pro-Health® versus commonly prescribed toothbrushes, two randomly assigned groups of 23 orthodontic patients each, were evaluated. One group of patients used commonly prescribed toothbrushes and the second group used Cross Action Pro-Health®. O`Leary, modified gingival and Bracket plaque index were measured before and 45 days after the daily use of the two mentioned toothbrushes prescriptions. T-test was used to detect statistically significant differences among the brushes for each index. The results demonstrated a significant reduction of the three indexes with the daily use of Cross Action Pro-Health® and no differences were found versus commonly used prescription. Orthodontic patients may benefit from the use of a single brush prescription (Cross Action Pro-Health®), because effective plaque removal can be achieved easier and faster.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0719-01072012000300002&nrm=is
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Cold temperature tolerance of the alien Indo-Pacific damselfish Neopomacentrus cyanomos from the Southern Gulf of Mexico
The abundance of the alien, Indo-Pacific damselfish Neopomacentrus cyanomos on an oil-loading platform in the southwest Gulf of Mexico indicates that widely distributed platforms could facilitate the expansion of its geo- graphic range across the western and northern fringes of the Gulf. From there it likely will spread to other areas of the Greater Caribbean. The lionfish example demonstrates that it eventually happens, and can do so rapidly. Reduced temperature effects on the physiology of this species were examined to better predict its survivability in the northern Gulf during winter, when sea surface temperatures fall as low as 15 °C along the coast. Overall, our results show that when the degree of experimental temperature decline was large and rapid, no compensation occurred and the stress response observed mostly reflected cellular processes that minimized damage. Integrated biomarker response values were significantly different between fish rapidly exposed to colder vs. warmer temperatures (declines of −4 °C each day, from 26 to 14 °C), reflected in higher values of blood metabolites and routine metabolic rates observed in fish exposed to 14 and 18 °C respectively, and lower activity of all enzymes, lower protein carbonylation, and higher oxidative damage to lipids in fish exposed to 14 °C. While the phy- siological proxies responded to minimize damage during the rapid-decrease experiment, the same proxies re- flected the consequences of compensation when fish were thermally challenged after a 45 days acclimation at 18 °C. In this case, lower values of blood metabolites and high antioxidant levels and indicators of damages underpinned its pejus lower range. Based on the results of the present work, it seems clear that low winter SSTs in the northern Gulf will slow down the colonization of the inshore area of N. cyanomos. We suggest that the use of physiological cellular stress markers on specimens acquired at the beginning of an invasion should be im- plemented in new standardized experimental protocols, including both rapid increases/decreases of temperature and post-acclimation temperature challenges, to assess the invasiveness potential of aquatic species such as this
Trends on epidemiological, virological, and clinical features among newly diagnosed HIV-1 persons in Northwest Spain over the last 10 years
[Abstract] To describe temporal trend and characteristics of newly HIV-diagnosed patients in a medical care area in Northwest Spain over the last 10 years. All newly diagnosed patients for HIV-infection from 2004 to 2013 at a reference medical care area in Northwest of Spain were identified. Epidemiological, virological, immunological, and clinical data, as well as HIV genotype and drug resistance information were recorded. A total of 565 newly HIV-diagnosed patients were identified. The number of new cases increased in the last 5 years (66 cases/year). Overall, 53.1% had a median CD4 counts < 350 cells/µl and 33.6% had an AIDS defining criteria. Non-B variants were found in 34.4% of patients being subtype F (25.8%) the most common non-B subtype. The rate of transmitted drug resistance (TDR) over the study period was 3.7%, but a decreased to 2.6% was observed in the last 5 years. The most prevalent TDR mutations were: T215 revertants (1.5%), K219QENR (1.2%), for NRTIs; K103N (1.9%), for NNRTIs; L90M (0.3%), for PIs. Overall, 73.2% of patients started antiretroviral treatment and 9.9% of patients died during follow-up. The number of newly HIV diagnosed patients increased since year 2009. There is a high prevalence of late diagnosis (53%) and 33% had an AIDS defining criteria. Interestingly, the most prevalent non-B subtype in our population was F (25.8%). These findings support the need to facilitate the access for HIV testing to reduce the rate of late HIV diagnosis, improve the clinical outcome and prevent HIV transmission.Instituto de Salud Carlos III; CP08/00214Instituto de Salud Carlos III; PI10/02166Instituto de Salud Carlos III; CM13/00328Instituto de Salud Carlos III; PI13/0226
Incidentaloma suprarrenal: ¿cuándo mantener la sospecha, aunque haya un buen lavado?
Se presenta a un hombre de 58 años, con hallazgo de masa incidental en la glándula suprarrenal izquierda. La tomografía computarizada de abdomen con protocolo para suprarrenales calculó un lavado absoluto del contraste de 72 %. La imagen de resonancia magnética de abdomen mostró intensidad de señal intermedia en T2 y baja en T1, sin presencia de grasa microscópica en secuencias eco gradiente fuera de fase. La bioquímica inicial fue normal, excepto por niveles de cortisol post dexametasona mayores de 1,8 ?g/dL y una 17-hidroxiprogesterona elevada. Se discute el enfoque diagnóstico y el abordaje de las lesiones suprarrenales
Tendencia de las hospitalizaciones, reingresos y mortalidad intrahospitalaria en los pacientes infectados por VIH entre 1993-2013: impacto de la coinfección por el virus de la hepatitis C
[Abstract] Background. New patterns in epidemiological characteristics of people living with HIV infection (PLWH) and the introduction of Highly Active Antiretroviral Therapy (HAART) have changed the profile of hospital admissions in this population. The aim of this study was to evaluate trends in hospital admissions, re-admissions, and mortality rates in HIV patients and to analyze the role of HCV co-infection.
Methods. A retrospective cohort study conducted on all hospital admissions of HIV patients between 1993 and 2013. The study time was divided in two periods (1993–2002 and 2003–2013) to be compared by conducting a comparative cross-sectional analysis.
Results. A total of 22,901 patient-years were included in the analysis, with 6917 hospital admissions, corresponding to 1937 subjects (75% male, mean age 36 ± 11 years, 37% HIV/HCV co-infected patients). The median length of hospital stay was 8 days (5–16), and the 30-day hospital re-admission rate was 20.1%. A significant decrease in hospital admissions related with infectious and psychiatric diseases was observed in the last period (2003–2013), but there was an increase in those related with malignancies, cardiovascular, gastrointestinal, and chronic respiratory diseases. In-hospital mortality remained high (6.8% in the first period vs. 6.3% in the second one), with a progressive increase of non-AIDS-defining illness deaths (37.9% vs. 68.3%, P < .001). The admission rate significantly dropped after 1996 (4.9% yearly), but it was less pronounced in HCV co-infected patients (1.7% yearly).
Conclusions. Hospital admissions due to infectious and psychiatric disorders have decreased, with a significant increase in non-AIDS-defining malignancies, cardiovascular, and chronic respiratory diseases. In-hospital mortality is currently still high, but mainly because of non-AIDS-defining illnesses. HCV co-infection increased the hospital stay and re-admissions during the study period.[Resumen] Introducción. Los cambios en las características epidemiológicas de los pacientes con infección por el VIH, y la introducción del tratamiento antirretroviral de alta eficacia, han modificado el perfil de las hospitalizaciones en esta población. El objetivo del estudio fue evaluar las tendencias en hospitalización, reingreso y mortalidad en pacientes VIH, y analizar el papel de la coinfección por el VHC.
Métodos. Estudio de cohortes retrospectivo, que incluyó todas las hospitalizaciones de pacientes VIH entre 1993-2013. El estudio fue dividido en 2 periodos (1993-2002 y 2003-2013) para ser comparados mediante un análisis transversal.
Resultados. Se analizaron 22.901 pacientes/años, que presentaron 6.917 hospitalizaciones que correspondieron a 1.937 pacientes (75% varones, edad media 36 ± 11 años, 37% coinfectados VIH/VHC). La mediana de estancia hospitalaria fue de 8 días (5-16), y la tasa de reingreso a los 30 días del 20,1%. Se observó un descenso significativo en el segundo periodo (2003-2013) de las hospitalizaciones motivadas por enfermedades infecciosas y trastornos psiquiátricos, y un incremento de aquellas relacionadas con neoplasias, enfermedad cardiovascular, gastrointestinal y enfermedades respiratorias crónicas. La mortalidad intrahospitalaria permanece elevada (6,8% en el primer periodo vs. 6,3% en el segundo), con un aumento progresivo de las muertes por enfermedades no definitorias de sida (37,9 vs. 68,3%; p < 0,001). La tasa de hospitalización disminuyó de manera significativa después de 1996 (4,9% anual), pero este descenso fue menos acusado en los pacientes coinfectados VIH/VHC (1,7% anual).
Conclusiones. Las hospitalizaciones motivadas por enfermedades infecciosas y trastornos psiquiátricos han descendido; por el contrario, se observó un aumento significativo de aquellas relacionadas con neoplasias no definitorias de sida, enfermedad cardiovascular y enfermedades respiratorias crónicas. La mortalidad intrahospitalaria permanece a día de hoy elevada, pero a expensas fundamentalmente de enfermedades no definitorias de sida. La coinfección VIH/VHC incrementó los días de hospitalización y los reingresos durante el periodo de estudio.Instituto de Salud Carlos III; CPII14/00014Instituto de Salud Carlos III; PI10/02166Instituto de Salud Carlos III; PI13/02266Instituto de Salud Carlos III; CM13/0032
Electronic Developments for the Hades RPC Wall: Overview and Progress
This contribution presents the current status and progress of the electronics developed for the Resistive Plate Chamber detector of HADES. This new detector for the time-of-flight detection system will contain more than 1000 RPC modules, covering a total active area of around 7 m2. The Front-End electronics consist of custom-made boards that exploit the benefit of the use of commercial components to achieve time resolutions below 100 ps. The Readout electronics, also custom-made, is a multipurpose board providing a 128- channel Time to Digital Converter (TDC) based on the HPTDC chip
Iberian acid peatlands: types, origin and general trends of development.
ABSTRACT: In the present study we reviewed the genesis, development and classification of peatlands in the Iberian 1. The region has a wide variety of peatlands which are classified according to their biogeochemical, geomorphological and ecological characteristics into different types of bogs and fens. 2. Most of the peatlands occur in the Atlantic region followed by the Mediterranean and Alpine regions. Fens are more widely distributed than bogs, and blanket and raised bogs are mainly found in the Eurosiberian biogeographical region. 3. In many of the fens, the last active peat-forming cycle occurred during the Late Holocene (43 %). In most of the bogs, the peat-forming cycle occurred in the Middle Holocene (70 %), although in a substantial proportion of blanket bogs these processes occurred in the Early Holocene (30 %). 4. The peat formed in the last active cycle is, on average, thicker in raised bogs (322 cm) than in blanket bogs (257 cm) and fens (156 cm). 5. Vertical peat accumulation rates varied between 16 and 30 yr cm-1 in more than 40 % of the peatlands. The accumulation rates differed significantly between the different types of peatlands and were highest in the raised bogs. The accumulation rates were very variable in the fens. 6. The genesis, evolution and types of Iberian peatlands are similar to those observed in peatlands in northern latitudes in Europe and North America.Our research has been made possible by the following project grants: INCITE09-200-019-PR (Xunta de Galicia Government); DESIRÈ-HAR2013-43701-P (Spanish Ministry of Economy and Competitiveness); and Relictflora-P11-RNM-7033 (Excellence Research Projects Program from the Andalusian Government)
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