7,493 research outputs found
Temperature measurements in a multiphase fluid hammer
Papers presented to the 11th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 20-23 July 2015.Any satellite propulsion system is inactive at launching, having the liquid propellant confined into tanks and the propellant lines vacuum pumped or filled with a noncondensable gas (NCG) at low pressure. Once in orbit, the propulsion system performs the so-called priming maneuver that consists in filling these lines with the pressurized liquid propellant (hydrazine), by opening a fast isolation valve. The opening of this valve subsequently induces a fluid hammer,
together with various multiphase phenomena, such as cavitation
and gas desorption. On top of that, the adiabatic compression that the liquid propellant may experience can induce the explosive decomposition of hydrazine.
Nowadays, the propulsion systems are certify with CFD simulations, but the numerical models still need to be extended and validated to work with multiphase fluids. The aim of this paper is to study experimentally the pressure and temperature evolution in the propellant lines during water hammer occurrence. The creation of an experimental database is a requirement to validate the numerical tools modeling the propulsion systems.The present research activity was initiated and promoted by the European Space Research and Technology Centre of the European Space Agency (ESTEC/ESA). It has been also
founded by the Xunta de Galicia and European Regional Development Funds under grant GRC 2013-050.am201
PileLineGUI: a desktop environment for handling genome position files in next-generation sequencing studies
Next-generation sequencing (NGS) technologies are making sequence data available on an unprecedented scale. In this context, new catalogs of Single Nucleotide Polymorphism and mutations generated by resequencing studies are usually stored in genome position files (e.g. Variant Call Format, SAMTools pileup, BED, GFF) comprising of large lists of genomic positions, which are difficult to handle by researchers. Here, we present PileLineGUI, a novel desktop application primarily designed for manipulating, browsing and analysing genome position files (GPF), with specific support to somatic mutation finding studies. The developed tool also integrates a new genome browser module specially designed for inspecting GPFs. PileLineGUI is free, multiplatform and designed to be intuitively used by biomedical researchers. PileLineGUI is available at: http://sing.ei.uvigo.es/pileline/pilelinegui.html
Jets, knots and tails in planetary nebulae: NGC 3918, K 1-2 and Wray 17-1
We analyze optical images and high-resolution, long-slit spectra of three
planetary nebulae which possess collimated, low-ionization features. NGC 3918
is composed of an inner, spindle-shaped shell mildly inclined with respect to
the plane of the sky. Departing from the polar regions of this shell, we find a
two-sided jet expanding with velocities which increase linearly with distance
from 50 to 100 km/s. The jet is probably coeval with the inner shell (with the
age of approximately 1000 D yr, where D is the distance in kpc), suggesting
that its formation should be ascribed to the same dynamical processes which
also shaped the main nebula, and not to a more recent mass loss episode. We
discuss the formation of the aspherical shell and jet in the light of current
hydrodynamical and magnetohydrodynamical theories. K 1-2 is a planetary nebula
with a close binary nucleus which shows a collimated string of knots embedded
in a diffuse, elliptical shell. The knots expand with a velocity similar to
that of the elliptical nebula (25 km/s), except for an extended tail located
out of the main nebula, which linearly accelerates up to 45 km/s. We estimate
an inclination on the line of the sight of 40 degres for the string of knots;
once the orientation of the orbit is also determined, this information will
allow us to test the prediction of current theories of the occurrence of polar
jets from close binary systems. Wray 17-1 has a complex morphology, showing two
pairs of low-ionization structures located in almost perpendicular directions
from the central star, and embedded in a large, diffuse nebula. The two pairs
show notable similarities and differences, and their origin is very puzzling.Comment: 20 pages plus 10 figures. ApJ recently published (ApJ 523, 721
(1999)
The enigmatic central star of the planetary nebula PRTM 1
The central star of the planetary nebula PRTM 1 (PN G243.8-37.1) was
previously found to be variable by M. Pena and colleagues. As part of a larger
programme aimed towards finding post common-envelope binary central stars we
have monitored the central star of PRTM 1 spectroscopically and photometrically
for signs of variability. Over a period of ~3 months we find minimal radial
velocity (<10 km/s) and photometric (< 0.2 mag) variability. The data suggest a
close binary nucleus can be ruled out at all but the lowest orbital
inclinations, especially considering the spherical morphology of the nebula
which we reveal for the first time. Although the current data strongly support
the single star hypothesis, the true nature of the central star of PRTM 1
remains enigmatic and will require further radial velocity monitoring at higher
resolution to rule out a close binary. If in the odd case that it is a close
binary, it would be the first such case in a spherical planetary nebula, in
contradiction to current thinking.Comment: A&A, in pres
Cuticular wax composition in Cocos nucifera L.: physicochemical analysis of wax components and mapping of their QTLs onto the coconut molecular linkage map
Impacto de las llamadas telefónicas en una unidad de hospitalización a domicilio
The Home Hospitalization Units (HAD) perform complex care at the hospital level to patients who are at home. One of the essential criteria for being admitted to this service is the ability to contact the HAD team by telephone so that the patient and the caregiver can be in permanent contact with the healthcare team. This inclusion criterion, however, involves an impact in the organization of the HAD, that respond to these demands since it can represent, sometimes, changes in the organization of the circuits, extraordinary emergency visits ... etc.
The telephone advice facilitates information and training for the empowerment of the patient and caregiver.
This study aims to collect and examine prospectively the impact that these calls have on the development of the work of the HAD team, as well as to evaluate the reasons that generate them to work in line with the continuous improvement.Las unidades de hospitalización a domicilio (HAD) realizan cuidados complejos de nivel hospitalario a los pacientes que están en casa. Uno de los criterios esenciales para ser admitido en este servicio es tener la posibilidad de comunicarse con el equipo de HAD por teléfono para que el paciente y el cuidador puedan estar en contacto permanente con dicho equipo de atención multidisciplinar domiciliaria. Este criterio de inclusión, sin embargo, implica un impacto en la organización de las Unidades de HAD que responden a estas demandas ya que puede representar, a veces, cambios en la organización de los circuitos, visitas extraordinarias de urgencia ... etc.
El asesoramiento telefónico facilita información y capacitación para el empoderamiento del paciente y del cuidador.
Este estudio tiene como objetivo recopilar y examinar prospectivamente el impacto que estas llamadas tienen en el desarrollo del trabajo del equipo HAD, así como evaluar las razones que los generan para trabajar en la línea de la mejora continua
Ultrafast Dynamics of Nitro−Nitrite Rearrangement and Dissociation in Nitromethane Cation
We report new insights into the ultrafast rearrange- ment and dissociation dynamics of nitromethane cation (NM+) using pump−probe measurements, electronic structure calculations, and ab initio molecular dynamics simulations. The “roaming” nitro−nitrite rearrangement (NNR) pathway involving large- amplitude atomic motion, which has been previously described for neutral nitromethane, is demonstrated for NM+. Excess energy resulting from initial population of the electronically excited D2 state of NM+ upon strong-field ionization provides the necessary energy to initiate NNR and subsequent dissociation into NO+. Both pump−probe measurements and molecular dynamics simulations are consistent with the completion of NNR within 500 fs of ionization with dissociation into NO+ and OCH3 occurring ∼30 fs later. Pump−probe measurements indicate that NO+ formation is in competition with the direct dissociation of NM+ to CH3+ and NO2. Electronic structure calculations indicate that a strong D0 → D1 transition can be excited at 650 nm when the C−N bond is stretched from its equilibrium value (1.48 Å) to 1.88 Å. On the other hand, relaxation of the NM+ cation after ionization into D0 occurs in less than 50 fs and results in observation of intact NM+. Direct dissociation of the equilibrium NM+ to produce NO2+ and CH3 can be induced with 650 nm excitation via a weakly allowed D0 → D2 transition
Micro and nano-patterning of single-crystal diamond by swift heavy ion irradiation
This paper presents experimental data and analysis of the structural damage caused by swift-heavy ion irradiation of single-crystal diamond. The patterned buried structural damage is shown to generate, via swelling, a mirror- pattern on the sample surface, which remains largely damage-free. While extensive results are available for light ion implantations, this effect is reported here for the first time in the heavy ion regime,where a completely different range of input parameters (in terms of ion species, energy, stopping power, etc.) is available for customized irradiation. The chosen ion species are Au and Br, in the energy range 10–40 MeV. The observed patterns, as characterized by profilometry and atomic force microscopy, are reported in a series ofmodel experiments,which show swelling patterns ranging from a few nm to above 200 nm. Moreover, a systematic phenomenological modeling is presented, inwhich surface swelling measurements are correlated to buried crystal damage. A comparison ismade with data for light ion implantations, showing good compatibilitywith the proposedmodels. The modeling presented in thiswork can be useful for the design and realization of micropatterned surfaces in single crystal diamond, allowing generating highly customized structures by combining appropriately chosen irradiation parameters and masks
Clinical Risk Score to Predict Pathogenic Genotypes in Patients With Dilated Cardiomyopathy
Background: Although genotyping allows family screening and influences risk-stratification in patients with nonischemic dilated cardiomyopathy (DCM) or isolated left ventricular systolic dysfunction (LVSD), its result is negative in a significant number of patients, limiting its widespread adoption.
Objectives: This study sought to develop and externally validate a score that predicts the probability for a positive genetic test result (G+) in DCM/LVSD.
Methods: Clinical, electrocardiogram, and echocardiographic variables were collected in 1,015 genotyped patients from Spain with DCM/LVSD. Multivariable logistic regression analysis was used to identify variables independently predicting G+, which were summed to create the Madrid Genotype Score. The external validation sample comprised 1,097 genotyped patients from the Maastricht and Trieste registries.
Results: A G+ result was found in 377 (37%) and 289 (26%) patients from the derivation and validation cohorts, respectively. Independent predictors of a G+ result in the derivation cohort were: family history of DCM (OR: 2.29; 95% CI: 1.73-3.04; P < 0.001), low electrocardiogram voltage in peripheral leads (OR: 3.61; 95% CI: 2.38-5.49; P < 0.001), skeletal myopathy (OR: 3.42; 95% CI: 1.60-7.31; P = 0.001), absence of hypertension (OR: 2.28; 95% CI: 1.67-3.13; P < 0.001), and absence of left bundle branch block (OR: 3.58; 95% CI: 2.57-5.01; P < 0.001). A score containing these factors predicted a G+ result, ranging from 3% when all predictors were absent to 79% when ≥4 predictors were present. Internal validation provided a C-statistic of 0.74 (95% CI: 0.71-0.77) and a calibration slope of 0.94 (95% CI: 0.80-1.10). The C-statistic in the external validation cohort was 0.74 (95% CI: 0.71-0.78).
Conclusions: The Madrid Genotype Score is an accurate tool to predict a G+ result in DCM/LVSD
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