3,134 research outputs found
Sensibilidad a la colocación de los marcadores en el modelo convencional de análisis cinemático de la marcha
La correcta evaluación del movimiento articular a través de sistemas de análisis del movimiento depende, entre otros factores, de la correcta colocación de los marcadores reflectantes sobre los sujetos analizados. En el modelo convencional de marcha, de los 15 marcadores de miembro inferior, la mayoría se localizan en puntos anatómicos fáciles de localizar y que tienen poca posibilidad de error. Sin embargo, hay dificultad en otros, como el de la articulación de la rodilla y, sobre todo, en los del muslo y pierna.
En el estudio, se empleó un sistema VICON 460, con el que se analizó la cinemática de miembro inferior de 5 sujetos adultos sanos (2 mujeres, 3 varones). Para evaluar los movimientos articulares se empleó el modelo convencional de marcha. Determinada la posición correcta de los marcadores en cada sujeto, se procedió a la variación por separado de los marcadores de la rodilla, el muslo y la pierna, moviendo cada uno 15 mm anterior y posteriormente con relación a la posición inicial.
Estos pequeños desplazamientos producen importantes variaciones en los resultados cinemáticos obtenidos. Entre ellas en el varo-valgo de rodilla, parámetro que es de gran utilidad a la hora de detectar errores en la colocación de los marcadores
Lesiones en el manguito rotador tras luxación anterior de hombro en pacientes mayores de 40 años.
Se ha realizado un estudio prospectivo de la evolución de 32 luxaciones anteriores de hombro en pacientes
de más de 40 años con el objetivo de establecer la incidencia, localización y tipo de rotura del manguito rotador
a causa de la luxación, conocer evolución clínica y establecer los criterios clínicos que nos permitan sospechar
una rotura del manguito rotador, sin necesidad de recurrir a resonancia magnética (RM) de entrada. Los pacientes fueron
sometidos a estudio mediante RM, clasificando las lesiones observadas en cinco grados en función de la extensión
de la rotura, siendo el grupo 1 la integridad del manguito. El 90% de los casos presentó una rotura del manguito
rotador asociada a la luxación. Tras un periodo de rehabilitación se demostró una diferencia significativa en la recuperación
de la abducción en los pacientes con manguito íntegro, siendo un signo clínico de importancia para valorar
el estado del manguito rotador.A prospective study of the evolution of 32 anterior dislocations of the shoulder in patients older than forty
years has been done with the objective of establishing the incidence, location and kind of tear caused by the
dislocation, to know the evolution and to establish the clinical parameters that allow us to suspect an injury of the
rotator cuff without the help of magnetic resonance (MR) in the beginning. All the patients were studied with MR,
doing a classification of the tears in five degrees, depending on the extension of the tears, being the group 1 the
integrity of the rotator cuff. In 90% of the cases a rotator cuff tear has been found to be associated with the dislocation.
After the rehabilitation, a significative difference in the recovery of the abduction has been demonstrated in the
patients with integrity of the rotator cuff, being an important clinical sign to know the state of the rotator cuff
Towards a more complete description of nucleon distortion in lepton-induced single-pion production at low-
Theoretical predictions for lepton-induced single-pion production (SPP) on
C are revisited in order to assess the effect of different treatments of
the current operator. On one hand we have the asymptotic approximation, which
consists in replacing the particle four-vectors that enter in the operator by
their asymptotic values, i.e., their values out of the nucleus. On the other
hand we have the full calculation, which is a more accurate approach to the
problem. We also compare with results in which the final nucleon is described
by a relativistic plane wave, to rate the effect of the nucleon distortion. The
study is performed for several lepton kinematics, reproducing inclusive and
semi-inclusive cross sections belonging to the low- region (between 0.05
and 1 GeV), which is of special interest in charged-current (CC)
neutrino-nucleus 1 production. Inclusive electron results are compared
with experimental data. We find non-trivial corrections comparable in size with
the effect of the nucleon distortion, namely, corrections up to 6\%, either
increasing or diminishing the asymptotic prediction, and a shift of the
distributions towards higher energy transfer. For the semi-inclusive cross
sections, we observe the correction to be prominent mainly at low values of the
outgoing nucleon kinetic energy. Finally, for CC neutrino-induced 1
production, we find a reduction at low- with respect to both the
plane-wave approach and the asymptotic case
Presencia de Linfocitos T Reguladores en Periodontitis Crónica
ResumenLa enfermedad periodontal requiere de un hospedero susceptible para su desarrollo y progresión. Dentro de las características del hospedero se encuentra la respuesta T reguladora, que otorga tolerancia frente a antígenos propios y participa durante las enfermedades infecciosas limitando el daño tisular, sin disminuir la respuesta antibacteriana. El presente estudio tiene por objetivo determinar la presencia, reclutamiento y función de Tregs en pacientes con periodontitis crónica. En 10 biopsias de tejido periodontal sano y con periodontits crónica se realizó inmunohistoquímica para marcadores (CD4, CD25, Foxp3), quimioquinas (CCL17, CCL22) y citoquinas (TGF-β, IL-10) de Tregs. Además de Western-Blot para detectar las citoquinas. Los resultados obtenidos sugieren una posible asociación entre células Tregs y la infección periodontal, ya que se confirma su reclutamiento y presencia. Sin embargo, son necesarios más estudios del posible desbalance con su contraparte pro-inflamatoria Th17, que expliquen en parte la compleja etiopatogenia de la enfermedad periodontal.AbstractPeriodontal disease requires a susceptible host to initiation, development and progression. T regulatory response is one of these inmunoregulatory characteristics of the susceptible host, which provide tolerance, tissular protection during infection without impairing the control of periodontopathogens. The aim of this study is to determinate the presence, homing and function of T regulatory cells (Tregs) in patients with chronic periodontitis. Ten biopsies were taken from pockets, the presence of Tregs markers (CD4, CD25, Foxp3), chemokines (CCL17, CCL22) and cytokines (TGF-β, IL-10) were determinate by immunohistochemistry. Cytokines also were detected with Western-Blot. Our results suggest a possible association between Tregs and periodontal infection, confirming homing and presence of Tregs. However, further studies are required to determine the possible imbalance with pro-inflammatory part Th17, that might explain the complex etiopathogenesis of periodontal disease
Long-term effectiveness of sustainable land management practices to control runoff, soil erosion, and nutrient loss and the role of rainfall intensity in Mediterranean rainfed agroecosystems
Mediterranean environments are especially susceptible to soil erosion and to inappropriate soil management, leading to accelerated soil loss. Sustainable Land Management (SLM) practices (such as reduced tillage, no-tillage, cover crops, etc.,) have the potential to reduce soil, organic carbon (OC), and nutrient losses by erosion. However, the effectivity of these practices is site-dependent and varies under different rainfall conditions. The objective of this paper was to evaluate the effects of SLM practices in two rainfed systems (a wheat field and an almond orchard) representative of a large area of the driest Mediterranean regions - on runoff, soil erosion, particle size distribution, and OC and nutrient (N and P) contents in sediments. The influence of the rainfall characteristics on the effectiveness of the SLM practices was also evaluated. The SLM implemented were: reduced tillage (RT) in the wheat field and almond orchard and reduced tillage combined with green manure (RTG) in the almond orchard; these were compared to conventional tillage, the usual practice in the area. Open erosion plots were set up to monitor the effects of SLM on soil carbon and nutrients and on soil erosion after each rainfall event over six years (2010 2016). The results show that the SLM practices evaluated resulted in increased organic carbon (OC) and nutrients (N and P) contents in the soil, and reduced runoff, erosion, and mobilization of organic carbon and nutrients in sediments. Reductions in runoff of 30% and 65% and decreases in erosion of 65 and 85% were found in the wheat field and almond orchards, respectively. In addition, the total OC, N, and P losses in the wheat field were reduced by 56%, 45%, and 64%, respectively, while in the almond field the OC, N, and P losses were reduced by 90% under RT and by 85% under RTG. The beneficial effect of the SLM practices on soil erosion was observed within 18 months of their implementation and continued throughout the six years of the study. Furthermore, the effectiveness of tillage reduction with respect to erosion control and carbon and nutrients mobilization was highest during the most intense rainfall events, which are responsible for the highest erosion rates in Mediterranean areas. Our results support the key role of SLM practices under semiarid conditions as useful tools for climate change mitigation and adaptation, given the expected increase in high-intensity rainfall events in semiarid areas. © 2019 The AuthorsThis study site has been funded by several national (CYCIT AGL201125069//CICYT AGL2010-20941//CGL2013-42009-R//CGL2014-55-405-R), Regional (Séneca Foundation: 08757/PI/08//19350/PI/14), and European Commission H2020 (F6 DG RTD 037046 and Grant 728003, DIVERFARMING projects). Joris de Vente acknowledges support from a Ramón y Cajal research grant (RYC-2012-10375) and María Almagro was supported by the Juan de la Cierva Program (IJCI-2015-23500)
Constraints on gamma-ray burst and supernova progenitors through circumstellar absorption lines. (II): Post-LBV Wolf-Rayet stars
Van Marle et al. (2005) showed that circumstellar absorption lines in early
Type Ib/c supernova and gamma-ray burst afterglow spectra may reveal the
progenitor evolution of the exploding Wolf-Rayet star. While the quoted paper
deals with Wolf-Rayet stars which evolved through a red supergiant stage, we
investigate here the initially more massive Wolf-Rayet stars which are thought
to evolve through a Luminous Blue Variable (LBV) stage. We perform hydrodynamic
simulations of the evolution of the circumstellar medium around a 60 Msol star,
from the main sequence through the LBV and Wolf-Rayet stages, up to core
collapse. We then compute the column density of the circumstellar matter as a
function of radial velocity, time and angle. This allows a comparison with the
number and blue-shifts, of absorption components in the spectra of LBVs,
Wolf-Rayet stars, Type Ib/c supernovae and gamma-ray burst afterglows. Our
simulation for the post-LBV stage shows the formation of various absorption
components, which are, however, rather short lived; they dissipate on time
scales shorter than 50,000yr. As the LBV stage is thought to occur at the
beginning of core helium burning, the remaining Wolf-Rayet life time is
expected to be one order of magnitude larger. When interpreting the absorption
components in the afterglow spectrum of GRB-021004 as circumstellar, it can be
concluded that the progenitor of this source did most likely not evolve through
an LBV stage. However, a close binary with late common-envelope phase (Case C)
may produce a circumstellar medium that closely resembles the LBV to Wolf-Rayet
evolution, but with a much shorter Wolf-Rayet period.Comment: accepted for publication by A&
Universal behavior for magnetic entropy change in magnetocaloric materials: An analysis on the nature of phase transitions
The magnetic field toward the young planetary nebula K~3-35
K 3-35 is a planetary nebula (PN) where H2O maser emission has been detected,
suggesting that it departed from the proto-PNe phase only some decades ago.
Interferometric VLA observations of the OH 18 cm transitions in K~3-35 are
presented.OH maser emission is detected in all four ground state lines (1612,
1665, 1667, and 1720 MHz). All the masers appear blueshifted with respect to
the systemic velocity of the nebula and they have different spatial and
kinematic distributions.The OH 1665 and 1720 MHz masers appear spatially
coincident with the core of the nebula, while the OH 1612 and 1667 MHz ones
exhibit a more extended distribution. We suggest that the 1665 and 1720 masers
arise from a region close to the central star, possibly in a torus, while the
1612 and 1667 lines originate mainly from the extended northern lobe of the
outflow. It is worth noting that the location and velocity of the OH 1720 MHz
maser emission are very similar to those of the H2O masers (coinciding within
0.1" and ~2 km/s, respectively). We suggest that the pumping mechanism in the
H2O masers could be produced by the same shock that is exciting the OH 1720 MHz
transition. A high degree of circular polarization (>50%) was found to be
present in some features of the 1612, 1665, and 1720 MHz emission.For the 1665
MHz transition at ~ +18 km/s the emission with left and right circular
polarizations (LCP and RCP) coincide spatially within a region of ~0.03" in
diameter.Assuming that these RCP and LCP 1665 features come from a Zeeman pair,
we estimate a magnetic field of ~0.9 mG within 150 AU from the 1.3 cm continuum
peak. This value is in agreement with a solar-type magnetic field associated
with evolved stars.Comment: 6 pages, 2 tables, 4 figures, ApJ accepte
- …