360 research outputs found
Problemática de los recubrimientos superficiales realizados con láser e influencia de los parámetros de proceso
Maritime antarctic lakes as sentinels of climate change
Remote lakes, such as lakes from the Maritime Antarctica, can be used as sentinels of climate change, because
they are mostly free of direct anthropogenic pressures, and they experience climate change as a main stressor
capable of modifying the ecosystem structure and function. In this paper, the content of a lecture that has been
presented at the First Conference of Lake Sustainability, which has been centred in our studies on lakes from
Byers Peninsula (Maritime Antarctica), are summarized. These included physical, chemical and biological
studies of these lakes and other freshwater ecosystems, which highlighted the relevance of biotic interactions
for these ecosystems and its sensibility to temperature variations and to biological invasions, which is of rel-
evance given the acute regional warming occurring during the last decades in the area, concomitant with the
enhancement of dispersion of alien species linked to the increased presence of humans
Vav3 Is Involved in GABAergic Axon Guidance Events Important for the Proper Function of Brainstem Neurons Controlling Cardiovascular, Respiratory, and Renal Parameters
Vav3 is a phosphorylation GDP/GTP exchange factor for Rho/Rac GTPases. Recently, it has been described that Vav3 knockout mice develop hypertension and sympathoexcitation. In this work, we report the neurological cause of this phenotype
Feedback and feeding in the context of galaxy evolution with SPICA: direct characterization of molecular outflows and inflows
A far-infrared observatory such as the {\it SPace Infrared telescope for
Cosmology and Astrophysics} ({\it SPICA}), with its unprecedented spectroscopic
sensitivity, would unveil the role of feedback in galaxy evolution during the
last Gyr of the Universe (), through the use of far- and
mid-infrared molecular and ionic fine structure lines that trace outflowing and
infalling gas. Outflowing gas is identified in the far-infrared through P-Cygni
line shapes and absorption blueshifted wings in molecular lines with high
dipolar moments, and through emission line wings of fine-structure lines of
ionized gas. We quantify the detectability of galaxy-scale massive molecular
and ionized outflows as a function of redshift in AGN-dominated,
starburst-dominated, and main-sequence galaxies, explore the detectability of
metal-rich inflows in the local Universe, and describe the most significant
synergies with other current and future observatories that will measure
feedback in galaxies via complementary tracers at other wavelengths.Comment: This paper belongs to the SPICA Special Issue on PASA. Accepted for
publication in PAS
Selecting promising classes from generated data for an efficient multi-class nearest neighbor classification
The nearest neighbor rule is one of the most considered algorithms for supervised learning because of its simplicity and fair performance in most cases. However, this technique has a number of disadvantages, being the low computational efficiency the most prominent one. This paper presents a strategy to overcome this obstacle in multi-class classification tasks. This strategy proposes the use of Prototype Reduction algorithms that are capable of generating a new training set from the original one to try to gather the same information with fewer samples. Over this reduced set, it is estimated which classes are the closest ones to the input sample. These classes are referred to as promising classes. Eventually, classification is performed using the original training set using the nearest neighbor rule but restricted to the promising classes. Our experiments with several datasets and significance tests show that a similar classification accuracy can be obtained compared to using the original training set, with a significantly higher efficiency.This work has been supported by the Vicerrectorado de Investigación, Desarrollo e Innovación de la Universidad de Alicante through the FPU programme (UAFPU2014–5883), the Spanish Ministerio de Educación, Cultura y Deporte through a FPU Fellowship (Ref. AP2012–0939) and the Spanish Ministerio de Economía y Competitividad through Project TIMuL (No. TIN2013-48152-C2-1-R, supported by UE FEDER funds)
Limits to dark matter annihilation cross-section from a combined analysis of MAGIC and Fermi-LAT observations of dwarf satellite galaxies
We present the first joint analysis of gamma-ray data from the MAGIC
Cherenkov telescopes and the Fermi Large Area Telescope (LAT) to search for
gamma-ray signals from dark matter annihilation in dwarf satellite galaxies. We
combine 158 hours of Segue 1 observations with MAGIC with 6-year observations
of 15 dwarf satellite galaxies by the Fermi-LAT. We obtain limits on the
annihilation cross-section for dark matter particle masses between 10 GeV and
100 TeV - the widest mass range ever explored by a single gamma-ray analysis.
These limits improve on previously published Fermi-LAT and MAGIC results by up
to a factor of two at certain masses. Our new inclusive analysis approach is
completely generic and can be used to perform a global, sensitivity-optimized
dark matter search by combining data from present and future gamma-ray and
neutrino detectors.Comment: 19 pages, 3 figures. V2: Few typos corrected and references added.
Matches published version JCAP 02 (2016) 03
Discovery of Very High Energy gamma-rays from 1ES 1011+496 at z=0.212
We report on the discovery of Very High Energy (VHE) gamma-ray emission from
the BL Lacertae object 1ES1011+496. The observation was triggered by an optical
outburst in March 2007 and the source was observed with the MAGIC telescope
from March to May 2007. Observing for 18.7 hr we find an excess of 6.2 sigma
with an integrated flux above 200 GeV of (1.58 photons
cm s. The VHE gamma-ray flux is >40% higher than in March-April
2006 (reported elsewhere), indicating that the VHE emission state may be
related to the optical emission state. We have also determined the redshift of
1ES1011+496 based on an optical spectrum that reveals the absorption lines of
the host galaxy. The redshift of z=0.212 makes 1ES1011+496 the most distant
source observed to emit VHE gamma-rays up to date.Comment: 4 pages, 6 figures, minor changes to fit the ApJ versio
MAGIC observations of very high energy gamma-rays from HESS J1813-178
Recently, the HESS collaboration has reported the detection of gamma-ray
emission above a few hundred GeV from eight new sources located close to the
Galactic Plane. The source HESS J1813-178 has sparked particular interest, as
subsequent radio observations imply an association with SNR G12.82-0.02.
Triggered by the detection in VHE gamma-rays, a positionally coincident source
has also been found in INTEGRAL and ASCA data. In this Letter we present MAGIC
observations of HESS J1813-178, resulting in the detection of a differential
gamma-ray flux consistent with a hard-slope power law, described as dN/(dA dt
dE) = (3.3+/-0.5)*10^{-12} (E/TeV)^{-2.1+/-0.2} cm^(-2)s^(-1)TeV^(-1). We
briefly discuss the observational technique used, the procedure implemented for
the data analysis, and put this detection in the perspective of multifrequency
observations.Comment: Accepted by ApJ Letter
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