231 research outputs found
Early Science with the Large Millimetre Telescope: Molecules in the Extreme Outflow of a proto-Planetary Nebula
Extremely high velocity emission likely related to jets is known to occur in
some proto-Planetary Nebulae. However, the molecular complexity of this
kinematic component is largely unknown. We observed the known extreme outflow
from the proto-Planetary Nebula IRAS 16342-3814, a prototype water fountain, in
the full frequency range from 73 to 111 GHz with the RSR receiver on the Large
Millimetre Telescope. We detected the molecules SiO, HCN, SO, and CO.
All molecular transitions, with the exception of the latter are detected for
the first time in this source, and all present emission with velocities up to a
few hundred km s. IRAS 16342-3814 is therefore the only source of this
kind presenting extreme outflow activity simultaneously in all these molecules,
with SO and SiO emission showing the highest velocities found of these species
in proto-Planetary Nebulae. To be confirmed is a tentative weak SO component
with a FWHM 700 km s. The extreme outflow gas consists of dense
gas (n 10--10 cm), with a mass larger than
0.02--0.15 M. The relatively high abundances of SiO and SO may
be an indication of an oxygen-rich extreme high velocity gas.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical
Society Letter
Dynamics and Thermodynamics of Systems with Long Range Interactions: an Introduction
We review theoretical results obtained recently in the framework of
statistical mechanics to study systems with long range forces. This fundamental
and methodological study leads us to consider the different domains of
applications in a trans-disciplinary perspective (astrophysics, nuclear
physics, plasmas physics, metallic clusters, hydrodynamics,...) with a special
emphasis on Bose-Einstein condensates.Comment: Chapter of the forthcoming "Lecture Notes in Physics" volume:
``Dynamics and Thermodynamics of Systems with Long Range Interactions'', T.
Dauxois, S. Ruffo, E. Arimondo, M. Wilkens Eds., Lecture Notes in Physics
Vol. 602, Springer (2002). (see http://link.springer.de/series/lnpp/
The clumpy structure of Eridani's debris disc revisited by ALMA
Eridani is the closest star to our Sun known to host a debris
disc. Prior observations in the (sub-)millimetre regime have potentially
detected clumpy structure in the disc and attributed this to interactions with
an (as yet) undetected planet. However, the prior observations were unable to
distinguish between structure in the disc and background confusion. Here we
present the first ALMA image of the entire disc, which has a resolution of
1.6"1.2". We clearly detect the star, the main belt and two point
sources. The resolution and sensitivity of this data allow us to clearly
distinguish background galaxies (that show up as point sources) from the disc
emission. We show that the two point sources are consistent with background
galaxies. After taking account of these, we find that resolved residuals are
still present in the main belt, including two clumps with a
significance -- one to the east of the star and the other to the northwest. We
perform -body simulations to demonstrate that a migrating planet can form
structures similar to those observed by trapping planetesimals in resonances.
We find that the observed features can be reproduced by a migrating planet
trapping planetesimals in the 2:1 mean motion resonance and the symmetry of the
most prominent clumps means that the planet should have a position angle of
either or . Observations over multiple epochs
are necessary to test whether the observed features rotate around the star.Comment: 16 pages, 10 figures, accepted for publication in MNRA
MAPlex: A massively parallel sequencing ancestry analysis multiplex for Asia-Pacific populations
© 2019 The Authors Current forensic ancestry-informative panels are limited in their ability to differentiate populations in the Asia-Pacific region. MAPlex (Multiplex for the Asia-Pacific), a massively parallel sequencing (MPS) assay, was developed to improve differentiation of East Asian, South Asian and Near Oceanian populations found in the extensive cross-continental Asian region that shows complex patterns of admixture at its margins. This study reports the development of MAPlex; the selection of SNPs in combination with microhaplotype markers; assay design considerations for reducing the lengths of microhaplotypes while preserving their ancestry-informativeness; adoption of new population-informative multiple-allele SNPs; compilation of South Asian-informative SNPs suitable for forensic AIMs panels; and the compilation of extensive reference and test population genotypes from online whole-genome-sequence data for MAPlex markers. STRUCTURE genetic clustering software was used to gauge the ability of MAPlex to differentiate a broad set of populations from South and East Asia, the West Pacific regions of Near Oceania, as well as the other globally distributed population groups. Preliminary assessment of MAPlex indicates enhanced South Asian differentiation with increased divergence between West Eurasian, South Asian and East Asian populations, compared to previous forensic SNP panels of comparable scale. In addition, MAPlex shows efficient differentiation of Middle Eastern individuals from Europeans. MAPlex is the first forensic AIM assay to combine binary and multiple-allele SNPs with microhaplotypes, adding the potential to detect and analyze mixed source forensic DNA
Search for galactic axions with a high-Q dielectric cavity
A haloscope of the QUAX-- experiment, composed of an high-Q resonant
cavity immersed in a 8 T magnet and cooled to ~K is operated to
search for galactic axion with mass . The design of
the cavity with hollow dielectric cylinders concentrically inserted in a OFHC
Cu cavity, allowed us to maintain a loaded quality-factor Q
during the measurements in presence of magnetic field. Through the cavity
tuning mechanism it was possible to modulate the resonance frequency of the
haloscope in the region ~GHz and thus acquire different
dataset at different resonance frequencies. Acquiring each dataset for about 50
minutes, combining them and correcting for the axion's signal
estimation-efficiency we set a limit on the axion-photon coupling
GeV with the confidence level
set at
The NIKA2 large-field-of-view millimetre continuum camera for the 30 m IRAM telescope
Context. Millimetre-wave continuum astronomy is today an indispensable tool for both general astrophysics studies (e.g. star formation, nearby galaxies) and cosmology (e.g. cosmic microwave background and high-redshift galaxies). General purpose, large-field-of-view instruments are needed to map the sky at intermediate angular scales not accessible by the high-resolution interferometers (e.g. ALMA in Chile, NOEMA in the French Alps) and by the coarse angular resolution space-borne or ground-based surveys (e.g. Planck, ACT, SPT). These instruments have to be installed at the focal plane of the largest single-dish telescopes, which are placed at high altitude on selected dry observing sites. In this context, we have constructed and deployed a three-thousand-pixel dual-band (150 GHz and 260 GHz, respectively 2 mm and 1.15 mm wavelengths) camera to image an instantaneous circular field-of-view of 6.5 arcmin in diameter, and configurable to map the linear polarisation at 260 GHz.
Aims. First, we are providing a detailed description of this instrument, named NIKA2 (New IRAM KID Arrays 2), in particular focussing on the cryogenics, optics, focal plane arrays based on Kinetic Inductance Detectors, and the readout electronics. The focal planes and part of the optics are cooled down to the nominal 150 mK operating temperature by means of an adhoc dilution refrigerator. Secondly, we are presenting the performance measured on the sky during the commissioning runs that took place between October 2015 and April 2017 at the 30-m IRAM telescope at Pico Veleta, near Granada (Spain).
Methods. We have targeted a number of astronomical sources. Starting from beam-maps on primary and secondary calibrators we have then gone to extended sources and faint objects. Both internal (electronic) and on-the-sky calibrations are applied. The general methods are described in the present paper.
Results. NIKA2 has been successfully deployed and commissioned, performing in-line with expectations. In particular, NIKA2 exhibits full width at half maximum angular resolutions of around 11 and 17.5 arcsec at respectively 260 and 150 GHz. The noise equivalent flux densities are, at these two respective frequencies, 33±2 and 8±1 mJy s1/2. A first successful science verification run was achieved in April 2017. The instrument is currently offered to the astronomy community and will remain available for at least the following ten years
The relationship between the fishermen and the American crocodile (Crocodylus acutus) in the Mexican central western Pacific: a narrative analysis
Objective: Analyze fisherman-American crocodile relationship in western central Pacific Mexico, with emphasis on the conflict.
Design/methodology: Participatory workshops included 22 fishermen from the Cuyutlán and Alcuzahue lagoons in the state of Colima, to explore the positive and negative aspects of the relationship, the perception and knowledge about the ecosystem functions of the crocodile, the management practices and actions associated with these relationships, and to learn about the actors and natural factors that influence them. The information was recorded, followed by a narrative analysis and synthesis.
Results: Harmonious relationships are reported, such as creating bonds with crocodiles, and recognizing them as beneficial for fishing and their eco-systemic function. Conflicting relationships identified were related to fishing gear, reduction of fishing resources, and accidents. The strategies used to avoid conflicts are related to danger zones, crocodile behavior, and eliminating them to reduce their presence. They also consider compensatory schemes, co-collective management of fishery resources, and the substitution of fishing for the extractive exploitation of crocodiles.
Limitations on study/implications: It´s necessary to know the vision of other actors involved, besides fishermen.
Findings: The relationship between fishermen and crocodiles presents contradictory situations: harmonic where either are benefited, and other conflictive situations, where fishermen suffer economic, operational, and lifestyle impacts, producing scenarios that are not very favorable for the conservation of the reptile.Objective: To analyze the relationship between the fishermen of central western Mexico and the river crocodiles (Crocodylus acutus), emphasizing the resulting conflict.
Design/Methodology/Approach: The work was carried out with 22 fishermen from the Cuyutlán and Alcuzahue lagoons in Colima, Mexico. Four participative workshops were organized per community, in order to explore the positive and negative aspects of the relationship, the perception and knowledge about the ecosystem functions of the crocodile, and the management practices and actions associated with this relationship, as well as to determine the natural participants and factors that influence the said relationship. The workshops were recorded and the resulting data was subjected to a narrative analysis and a summary.
Results: Harmonious relationships are recorded, including the creation of bonds between humans and crocodiles and recognizing the benefits to fishing and the ecosystem function of the crocodile. The conflictive relationships identified were related to fishing, the reduction of fishing resources, and accidents. The strategies used to prevent conflicts are related to the dangerous zones, the behavior of the crocodiles, and the killing of the animals to reduce their presence. Additionally, compensation schemes, a collective management of fishing resources, and the replacement of fishing by the exploitation and capture of the crocodile were taken into consideration.
Study Limitations: Besides the fishermen’s, the point of view of other participants should be determined.
Conclusions: The relationship between fishermen and crocodiles is both harmonious and conflictive. On the one hand, both receive benefits; on the other hand, fishermen suffer economic, operative, and life style impacts, which create inauspicious scenarios for the conservation of the reptile
Replication of fifteen loci involved in human plasma protein N-glycosylation in 4,802 samples from four cohorts
Human protein glycosylation is a complex process, and its in vivo regulation is poorly understood. Changes in glycosylation patterns are associated with many human diseases and conditions. Understanding the biological determinants of protein glycome provides a basis for future diagnostic and therapeutic applications. Genome-wide association studies (GWAS) allow to study biology via a hypothesis-free search of loci and genetic variants associated with a trait of interest. Sixteen loci were identified by three previous GWAS of human plasma proteome N-glycosylation. However, the possibility that some of these loci are false positives needs to be eliminated by replication studies, which have been limited so far. Here, we use the largest set of samples so far (4,802 individuals) to replicate the previously identified loci. For all but one locus, the expected replication power exceeded 95%. Of the sixteen loci reported previously, fifteen were replicated in our study. For the remaining locus (near the KREMEN1 gene) the replication power was low, and hence replication results were inconclusive. The very high replication rate highlights the general robustness of the GWAS findings as well as the high standards adopted by the community that studies genetic regulation of protein glycosylation. The fifteen replicated loci present a good target for further functional studies. Among these, eight genes encode glycosyltransferases: MGAT5, B3GAT1, FUT8, FUT6, ST6GAL1, B4GALT1, ST3GAL4, and MGAT3. The remaining seven loci offer starting points for further functional follow-up investigation into molecules and mechanisms that regulate human protein N-glycosylation in vivo
Lo glocal y el turismo. Nuevos paradigmas de interpretación.
El estudio del turismo se realiza desde múltiples escalas y enfoques, este libro aborda muchos temas que es necesario discutir desde diversas perspectivas; es el caso de la reflexión sobre la propia disciplina y sus conceptos, así como los asuntos específicos referidos al impacto territorial, los tipos de turismo, las cuestiones ambientales, el tema de la pobreza, la competitividad, las políticas públicas, el papel de las universidades, las áreas naturales protegidas, la sustentabilidad, la cultura, el desarrollo, la seguridad, todos temas centrales documentados y expuestos con originalidad y dominio del asunto. Lo multiescalar es básico para la comprensión del sistema turístico, sistema formado de procesos globales, regionales y locales. El eje de discusión del libro es lo glocal, esa interacción entre lo nacional y local con lo global
Early science with the Large Millimetre Telescope: Deep LMT/AzTEC millimetre observations of ϵ Eridani and its surroundings
ϵ Eridani is a nearby, young Sun-like star that hosts a ring of cool debris analogous to the Solar system's Edgeworth-Kuiper belt. Early observations at (sub-)mm wavelengths gave tentative evidence of the presence of inhomogeneities in the ring, which have been ascribed to the effect of a putative low eccentricity planet, orbiting close to the ring. The existence of these structures has been recently challenged by high-resolution interferometric millimetre observations. Here, we present the deepest single-dish image of ϵ Eridani at millimetre wavelengths, obtained with the Large Millimetre Telescope Alfonso Serrano (LMT). The main goal of these LMT observations is to confirm (or refute) the presence of non-axisymmetric structure in the disc. The dusty ring is detected for the first time along its full projected elliptical shape. The radial extent of the ring is not spatially resolved and shows no evidence, to within the uncertainties, of dust density enhancements. Additional features of the 1.1 mm map are: (i) the presence of significant flux in the gap between the ring and the star, probably providing the first exo-solar evidence of Poynting-Robertson drag, (ii) an unambiguous detection of emission at the stellar positionwith a flux significantly above that expected from ϵ Eridani's photosphere, and (iii) the identification of numerous unresolved sources which could correspond to background dusty star-forming galaxies.This work would have not been possible without the long-term financial support from the Mexican Science and Technology Funding Agency, CONACyT (Consejo Nacional de Ciencia y Tecnología) during the construction and operational phase of the Large Millimetre Telescope Alfonso Serrano, as well as support from the US National Science Foundation via the University Radio Observatory program, the Instituto Nacional de Astrofísica, Optica y Electrónica (INAOE) and the University of Massachusetts, Amherst (UMass). MC, EB, FCSM, MO and RLV work was supported by CONACyT research grants SEP-2009-134985 and SEP-2011-169554. GMK is supported by the Royal Society as a Royal Society University Research Fellow. CE is partly supported by Spanish grant AYA2014-55840-P. JPM is supported by a UNSW Vice Chancellor's Postdoctoral Fellowship. SL acknowledges support from CONACyT through grant 238631
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