378 research outputs found
System and Method for Generating Psuedo-Noise Sequences
Disclosed is a method for generating psuedo-noise (PN) sequences utilizing a system comprised of a quantizer, and N directly quantized output/input map containing chaotic map cells, each in functional combination with combiner means and an m-bit shift register
ALMA Long Baseline Observations of the Strongly Lensed Submillimeter Galaxy HATLAS J090311.6+003906 at z=3.042
We present initial results of very high resolution Atacama Large
Millimeter/submillimeter Array (ALMA) observations of the =3.042
gravitationally lensed galaxy HATLAS J090311.6+003906 (SDP.81). These
observations were carried out using a very extended configuration as part of
Science Verification for the 2014 ALMA Long Baseline Campaign, with baselines
of up to 15 km. We present continuum imaging at 151, 236 and 290 GHz, at
unprecedented angular resolutions as fine as 23 milliarcseconds (mas),
corresponding to an un-magnified spatial scale of ~180 pc at z=3.042. The ALMA
images clearly show two main gravitational arc components of an Einstein ring,
with emission tracing a radius of ~1.5". We also present imaging of CO(10-9),
CO(8-7), CO(5-4) and H2O line emission. The CO emission, at an angular
resolution of ~170 mas, is found to broadly trace the gravitational arc
structures but with differing morphologies between the CO transitions and
compared to the dust continuum. Our detection of H2O line emission, using only
the shortest baselines, provides the most resolved detection to date of thermal
H2O emission in an extragalactic source. The ALMA continuum and spectral line
fluxes are consistent with previous Plateau de Bure Interferometer and
Submillimeter Array observations despite the impressive increase in angular
resolution. Finally, we detect weak unresolved continuum emission from a
position that is spatially coincident with the center of the lens, with a
spectral index that is consistent with emission from the core of the foreground
lensing galaxy.Comment: 9 pages, 5 figures and 3 tables, accepted for publication in the
Astrophysical Journal Letter
Informal rental housing in Colombia: an essential option for low-income households
Around the world, rental housing is frequently seen as secondary to home ownership; yet it plays a crucial role in many countries. In particular, rental housing in urban informal neighbourhoods has a critical but consistently overlooked role in housing the most vulnerable households in the Global South. If better policy and practice are to be pursued, there is a need for improved data on rental housing in urban informal settlements, and in particular, better understanding of ‘the lived experiences of the poor’. This paper responds to these empirical gaps in debates on informality and rental housing with qualitative research on residents’ experiences of informal rented housing in two Colombian cities, Bogotá and Cali. The paper frames informal rental housing as an essential option for diverse low-income households for whom ownership is not accessible or attractive. In this way, it also contributes to policy and theoretical debates calling for a better understanding of the dynamics, possibilities and potential of informal housing
Multidrug resistant pulmonary tuberculosis treatment regimens and patient outcomes: an individual patient data meta-analysis of 9,153 patients.
Treatment of multidrug resistant tuberculosis (MDR-TB) is lengthy, toxic, expensive, and has generally poor outcomes. We undertook an individual patient data meta-analysis to assess the impact on outcomes of the type, number, and duration of drugs used to treat MDR-TB
Catalytic pyrolysis of used tires on noble-metal-based catalysts to obtain high-value chemicals: Reaction pathways
A systematic study on the use of noble metals (Pd, Pt, Au) supported on titanate nanotubes (NT-Ti) for selectively producing BTX and p-cymene from waste tire pyrolysis is provided here. All the materials were characterized for chemical, textural and structural properties using a range of analytical techniques. The M/NT-Ti (M: Pd, Pt, or Au) catalysts exhibit low nanoparticle sizes (1.8 Pt ≈ Au > support > non-catalyst. The Py-GC/MS suggest that the catalysts participate in the secondary reactions of dealkylation, dehydrogenation, isomerization, aromatization, and cyclization leading to a higher formation of BTX than the uncatalyzed reaction. Finally, a comprehensive reaction pathway describing the catalytic pyrolysis of WT over Pd/NT-Ti was proposed by studying the catalytic pyrolysis of individual polymers constituting the waste tires, and D,L-Limonene.Puede accederse a los datos primarios de este trabajo haciendo clic en "Documentos relacionados".Centro de Investigación y Desarrollo en Ciencias Aplicada
Oleic acid variation and marker-assisted detection of Pervenets mutation in high- and low-oleic sunflower cross
High-oleic sunflower oil is in high demand on the market due to its heart-healthy properties and richness in monounsaturated fatty acids that makes it more stable in processing than standard sunflower oil. Consequently, one of sunflower breeder's tasks is to develop stable high-oleic sunflower genotypes that will produce high quality oil. We analyzed variability and inheritance of oleic acid content (OAC) in sunflower, developed at the Institute of Field and Vegetable Crops, by analyzing F-1 and F-2 progeny obtained by crossing a standard linoleic and high-oleic inbred line. F-2 individuals were classified in two groups: low-oleic with OAC of 15.24-31.28% and high-oleic with OAC of 62.49-93.82%. Monogenic dominant inheritance was observed. Additionally, several molecular markers were tested for the use in marker-assisted selection in order to shorten the period of detecting high-oleic genotypes. Marker F4-R1 was proven to be the most efficient in detection of genotypes with Pervenets (high-oleic acid) mutation
An Overview of the 2014 ALMA Long Baseline Campaign
A major goal of the Atacama Large Millimeter/submillimeter Array (ALMA) is to
make accurate images with resolutions of tens of milliarcseconds, which at
submillimeter (submm) wavelengths requires baselines up to ~15 km. To develop
and test this capability, a Long Baseline Campaign (LBC) was carried out from
September to late November 2014, culminating in end-to-end observations,
calibrations, and imaging of selected Science Verification (SV) targets. This
paper presents an overview of the campaign and its main results, including an
investigation of the short-term coherence properties and systematic phase
errors over the long baselines at the ALMA site, a summary of the SV targets
and observations, and recommendations for science observing strategies at long
baselines. Deep ALMA images of the quasar 3C138 at 97 and 241 GHz are also
compared to VLA 43 GHz results, demonstrating an agreement at a level of a few
percent. As a result of the extensive program of LBC testing, the highly
successful SV imaging at long baselines achieved angular resolutions as fine as
19 mas at ~350 GHz. Observing with ALMA on baselines of up to 15 km is now
possible, and opens up new parameter space for submm astronomy.Comment: 11 pages, 7 figures, 2 tables; accepted for publication in the
Astrophysical Journal Letters; this version with small changes to
affiliation
Optical and infrared flares from a transient Galactic soft gamma-ray repeater
Soft gamma-ray repeaters (SGRs) are a rare type of gamma-ray transient
sources that are ocasionally detected as bursts in the high-energy sky. They
are thought to be produced by magnetars, young neutron stars with very strong
magnetic fields of the order of 10^(14-15) G. Only three such objects are known
in our Galaxy, and a fourth one is associated with the supernova remnant N49 in
the Large Magellanic Cloud. In none of these cases has an optical counterpart
to either the gamma-ray flares or the quiescent source been identified. Here we
present multi-wavelength observations of a puzzling source, SWIFT
J195509+261406, for which we detected more than 40 flaring episodes in the
optical band over a time span of 3 days, plus a faint infrared flare 11 days
later, after which it returned to quiescence. We propose that SWIFT
J195509+261406 is a member of a subgroup of SGRs for which the long-term X-ray
emission is transient in nature. Furthermore, it is the first SGR for which
bursts have been detected in the optical and near-infrared bands and maybe the
link between the "persistent" SGRs and the dim isolated neutron stars.Comment: Version submitted to Nature on 31 Jan 2008. A substantially revised
version of this work has been published in Nature, vol. 455 issue 7212 pp
506-509 under the title "Flares from a Galactic magnetar suggest a missing
link to dim isolated neutron stars
Evaluation of diastolic function by three-dimensional volume tracking of the mitral annulus with cardiovascular magnetic resonance: comparison with tissue Doppler imaging
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