3,167 research outputs found
Trajectory planning of a quadrotor to monitor dependent people
This article introduces a framework for assisting dependent people at home through a vision-based autonomous unmanned aerial vehicle (UAV). Such an aircraft equipped with onboard cameras can be useful for monitoring and recognizing a dependent's activity. This work is focused on the problem of planning the flight path of a quadrotor to perform monitoring tasks. The objective is to design a trajectory planning algorithm that allows the UAV to position itself for the sake of capturing images of the dependent person's face. These images will be later treated by a base station to evaluate the persons emotional state, together with his/her behavior, this way determining the assistance needed in each situation. Numerical simulations have been carried out to validate the proposed algorithms. The results show the effectiveness of the trajectory planner to generate smooth references to our previously designed GPI (generalized proportional integral) controller. This demonstrates that a quadrotor is able to perform monitoring flights with a high motion precision.- This work has been partially supported by Spanish Ministerio de Ciencia, Innovacion y Universidades, Agencia Estatal de Investigacion (AEI)/European Regional Development Fund (FEDER, UE) under DPI2016-80894-R grant. Lidia M. Belmonte holds FPU014/05283 scholarship from Spanish Ministerio de Educacion y Formacion Profesional
Fijación de materiales biológicos mediante suturas y adhesivos biológicos
Las suturas son los elementos usados para fijar implantes o velos valvulares de las bioprótesis
cardiacas. Tienen gran resistencia, su escasa elasticidad genera tensiones internas en los elementos
que fijan. Se han comenzado a utilizar con fines médicos en la cirugía adherentes biológicos
como elementos de fijación aunque no hay experiencia en bioprótesis.
El objetivo de este trabajo era conocer si las muestras suturadas y pegadas eran capaces de
proporcionar resistencia y elasticidad suficiente como para aportar un beneficio a la sutura, en la
fijación de implantes o en la construcción de bioprótesis cardiacas. Para ello, hemos diseñado un
ensayo de resistencia a tracción de 60 muestras de pericardio de ternera, material que se utiliza
para fabricar velos valvulares de bioprótesis, comparando el comportamiento mecánico de 24
muestras suturadas con sutura continua borde a borde, prolene 5/0, a 45º y 90º del eje principal de
la carga y otras 24 muestras similares, en las que el ojal del hilo de sutura (o parte del tejido que
atraviesa la aguja de sutura) había sido reforzado con un adhesivo de fibrina. Como grupo de
control se emplearon doce muestras sin sutura ni adhesivo.
Los resultados obtenidos confirman la pérdida de resistencia al esfuerzo de tracción de las
muestras suturadas, borde a borde, independientemente de la dirección de la sutura en relación
con el eje principal de la carga. Esta forma de sutura no debe ser utilizada.
La pérdida de resistencia se manifiesta tras pequeñas deformaciones de las muestras de pericardio.
Para un 15% de deformación el estrés medio necesario para el grupo de control fue de 3.15 MPa
frente a 0.92 MPa y 1.98 MPa, valores extremos de las series suturadas (p<0.01).
Por otra parte, el uso de adherentes de fibrina no mejoró ni la resistencia ni la elasticidad de las
muestras, aunque homogenizó el comportamiento mecánico de aquellas muestras suturadas que
reforzaron con adherente de fibrina los ojales de paso de los hilos de sutura.Peer Reviewe
Unexplored outflows in nearby low luminosity AGNs: the case of NGC 1052
Outflows play a central role in galaxy evolution shaping the properties of
galaxies. Understanding outflows and their effects in low luminosity AGNs, such
as LINERs, is essential (e.g. they are a numerous AGN population in the local
Universe). We obtained VLT/MUSE and GTC/MEGARA optical IFS-data for NGC1052,
the prototypical LINER. The stars are distributed in a dynamically hot disc,
with a centrally peaked velocity dispersion map and large observed velocity
amplitudes. The ionised gas, probed by the primary component is detected up to
30arcsec (3.3 kpc) mostly in the polar direction with blue and red
velocities (V250 km/s). The velocity dispersion map shows a
notable enhancement (90 km/s) crossing the galaxy along the major
axis of rotation in the central 10arcsec. The secondary component has a bipolar
morphology, velocity dispersion larger than 150 km/s and velocities up to 660
km/s. A third component is detected but not spatially resolved. The maps of the
NaD absorption indicate optically thick neutral gas with a velocity field
consistent with a slow rotating disc (V = 7712 km/s) but the
velocity dispersion map is off-centred without any counterpart in the flux map.
We found evidence of an ionised gas outflow with mass of 1.60.6
10 Msun, and mass rate of 0.40.2 Msun/yr. The outflow is propagating
in a cocoon of gas with enhanced turbulence and might be triggering the onset
of kpc-scale buoyant bubbles (polar emission). Taking into account the energy
and kinetic power of the outflow (1.30.9 10 erg and
8.83.5 10 erg/s, respectively) as well as its alignment
with both the jet and the cocoon, and that the gas is collisionally ionised, we
consider that the outflow is jet-powered, although some contribution from the
AGN is possible.Comment: A&A accepted 04/04/2022, 31 pages, 12 figures and 3 appendixe
Elastic Image Registration of 2-D Gels for Differential and Repeatability Studies
One of the main applications of electrophoretic 2-D gels is the analysis of differential responses between different conditions. For this reason, specific spots are present in one of the images, but not in the other. In some other occasions, the same experiment is repeated between 2 and 12 times in order to increase statistical significance. In both situations, one of the major difficulties of these analysis is that 2-D gels are affected by spatial distortions due to run-time differences and dye-front deformations, resulting in images that are significantly dissimilar not only because of their content, but also because of their geometry. In this technical brief, we show how to use free, state-of-the-art image registration and fusion algorithms developed by us for solving the problem of comparing differential expression profiles, or computing an "average" image from a series of virtually identical gels
The cluster gas mass fraction as a cosmological probe: a revised study
(Abriged) We present the analysis of the baryonic content of 52 X-ray
luminous galaxy clusters observed with Chandra in the redshift range 0.3-1.273.
We use the deprojected X-ray surface brightness profiles and the measured
values of the gas temperature to recover the gas and total mass profiles. By
assuming that galaxy clusters are representative of the cosmic baryon budget,
the distribution of the cluster baryon fraction in the hottest (T> 4 keV)
systems as a function of redshift is used to constrain the cosmological
parameters. We discuss how our constraints are affected by several systematics,
namely the isothermality, the assumed baryon fraction in stars, the depletion
parameter and the sample selection. By using only the cluster baryon fraction
as a proxy for the cosmological parameters, we obtain that Omega is very well
constrained at the value of 0.35 with a relative statistical uncertainty of 11%
(1 sigma level; w=-1) and a further systematic error of about (-6,+7)%. On the
other hand, constraints on Lambda (without the prior of flat geometry) and w
(using the prior of flat geometry) are definitely weaker due to the presence of
larger statistical and systematic uncertainties (of the order of 40 per cent on
Lambda and larger than 50 per cent on w). If the WMAP 5-year best-fit results
are assumed to fix the cosmological parameters, we limit the contributions
expected from non-thermal pressure support and ICM clumpiness to be lower than
about 10 per cent, leaving also room to accommodate baryons not accounted for
either in the X-ray emitting plasma or in stars of the order of 18 per cent of
the total cluster baryon budget.Comment: A&A in press. Accepted on March 28, 2009. Revised to match version in
prin
Modular reorganization of the global network of gene regulatory interactions during perinatal human brain development.
BACKGROUND
During early development of the nervous system, gene expression patterns are known to vary widely depending on the specific developmental trajectories of different structures. Observable changes in gene expression profiles throughout development are determined by an underlying network of precise regulatory interactions between individual genes. Elucidating the organizing principles that shape this gene regulatory network is one of the central goals of developmental biology. Whether the developmental programme is the result of a dynamic driven by a fixed architecture of regulatory interactions, or alternatively, the result of waves of regulatory reorganization is not known.
RESULTS
Here we contrast these two alternative models by examining existing expression data derived from the developing human brain in prenatal and postnatal stages. We reveal a sharp change in gene expression profiles at birth across brain areas. This sharp division between foetal and postnatal profiles is not the result of pronounced changes in level of expression of existing gene networks. Instead we demonstrate that the perinatal transition is marked by the widespread regulatory rearrangement within and across existing gene clusters, leading to the emergence of new functional groups. This rearrangement is itself organized into discrete blocks of genes, each targeted by a distinct set of transcriptional regulators and associated to specific biological functions.
CONCLUSIONS
Our results provide evidence of an acute modular reorganization of the regulatory architecture of the brain transcriptome occurring at birth, reflecting the reassembly of new functional associations required for the normal transition from prenatal to postnatal brain development
Empirical leucine-to-carbon conversion factors for estimating heterothrophic bacterial production in surface waters of the world oceans
Comunicación oralBacterial biomass production is a key parameter for evaluating the role of bacterioplankton in ocean carbon cycling. However, bacterial production cannot be directly measured and is typically estimated from the incorporation rates of radiolabelled leucine. The conversion of leucine uptake rates into bacterial carbon production rates requires the use of conversion factors (CFs) which must be empirically determined. Despite the empirical leucine-to-carbon CFs vary widely across environments very little is known about its potential controlling factors. We conducted a set of 10 surface seawater cultures experiments where the growth of the natural bacterial assemblage was promoted by filtration (removal of grazers) or by both filtration and dilution. Sampling stations were located between 30 ºN and 30 ºS, including the Atlantic, Pacific and Indian oceans. CFs varied from 0.13 to 1.47 Kg C mol Leu-1, being higher in the filtrated than in the filtrated and diluted treatment. The abundance of picocyanobacteria explained 60% of the observed variability. Our results further suggest that the composition of bacterioplankton, as assessed by ARISA fingerprinting, may partially explain the observed variation in CFs
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