37 research outputs found
Elastic transport through dangling-bond silicon wires on H passivated Si(100)
We evaluate the electron transmission through a dangling-bond wire on
Si(100)-H (2x1). Finite wires are modelled by decoupling semi-infinite Si
electrodes from the dangling-bond wire with passivating H atoms. The
calculations are performed using density functional theory in a non-periodic
geometry along the conduction direction. We also use Wannier functions to
analyze our results and to build an effective tight-binding Hamiltonian that
gives us enhanced insight in the electron scattering processes. We evaluate the
transmission to the different solutions that are possible for the dangling-bond
wires: Jahn-Teller distorted ones, as well as antiferromagnetic and
ferromagnetic ones. The discretization of the electronic structure of the wires
due to their finite size leads to interesting transmission properties that are
fingerprints of the wire nature
Reversible 2D Phase Transition Driven by an Electric Field : Visualization and Control on the Atomic Scale
We report on a reversible structural phase transition of a two-dimensional system that can be locally induced by an external electric field. Two different structural configurations may coexist within a CO monolayer on Cu(111). The balance between the two phases can be shifted by an external electric field, causing the domain boundaries to move, increasing the area of the favored phase controllable both in location and size. If the field is further enhanced new domains nucleate. The arrangement of the CO molecules on the Cu surface is observed in real time and real space with atomic resolution while the electric field driving the phase transition is easily varied over a broad range. Together with the well-known molecular manipulation of CO adlayers, our findings open exciting prospects for combining spontaneous long-range order with man-made CO structures such as "molecule cascades" or "molecular graphene". Our new manipulation mode permits us to bridge the gap between fundamental concepts and the fabrication of arbitrary atomic patterns in large scale, by providing unprecedented insight into the physics of structural phase transitions on the atomic scale
SINBAD flight software, the on board software of NOMAD in ExoMars 2016
The Spacecraft INterface and control Board for NomAD (SINBAD) is an electronic interface designed by the Instituto de Astroffisica de Andalucfia (IAA-CSIC). It is part of the Nadir and Occultation for MArs Discovery instrument (NOMAD) on board in the ESAs ExoMars Trace Gas Orbiter mission. This mission was launched in March 2016. The SINBAD Flight Software (SFS) is the software embedded in SINBAD. It is in charge of managing the interfaces, devices, data, observing sequences, patching and contingencies of NOMAD. It is presented in this paper the most remarkable aspects of the SFS design, likewise the main problems and lessons learned during the software development process
SINBAD electronic models of the interface and control system for the NOMAD spectrometer on board of ESA ExoMars Trace Gas Orbiter mission
NOMAD is a spectrometer suite: UV-visible-IR spectral ranges. NOMAD is part of the payload of ESA ExoMars Trace Gas Orbiter Mission. SINBAD boards are in charge of the communication and management of the power and control between the spacecraft and the instrument channels. SINBAD development took four years, while the entire development and test required five years, a very short time to develop an instrument devoted to a space mission. The hardware of SINBAD is shown in the attached poster: developed boards, prototype boards and final models. The models were delivered to the ESA in order to testing and integration with the spacecraft
Risk factors for non-diabetic renal disease in diabetic patients
Background. Diabetic patients with kidney disease have a high prevalence of non-diabetic renal disease (NDRD). Renal and
patient survival regarding the diagnosis of diabetic nephropathy (DN) or NDRD have not been widely studied. The aim of
our study is to evaluate the prevalence of NDRD in patients with diabetes and to determine the capacity of clinical and
analytical data in the prediction of NDRD. In addition, we will study renal and patient prognosis according to the renal
biopsy findings in patients with diabetes.
Methods. Retrospective multicentre observational study of renal biopsies performed in patients with diabetes from 2002 to
2014.
Results. In total, 832 patients were included: 621 men (74.6%), mean age of 61.7 6 12.8 years, creatinine was 2.8 6 2.2 mg/dL
and proteinuria 2.7 (interquartile range: 1.2–5.4) g/24 h. About 39.5% (n ¼ 329) of patients had DN, 49.6% (n ¼ 413) NDRD and
10.8% (n ¼ 90) mixed forms. The most frequent NDRD was nephroangiosclerosis (NAS) (n ¼ 87, 9.3%). In the multivariate
logistic regression analysis, older age [odds ratio (OR) ¼ 1.03, 95% CI: 1.02–1.05, P < 0.001], microhaematuria (OR ¼ 1.51, 95%
CI: 1.03–2.21, P ¼ 0.033) and absence of diabetic retinopathy (DR) (OR ¼ 0.28, 95% CI: 0.19–0.42, P < 0.001) were independently
associated with NDRD. Kaplan–Meier analysis showed that patients with DN or mixed forms presented worse renal
prognosis than NDRD (P < 0.001) and higher mortality (P ¼ 0.029). In multivariate Cox analyses, older age (P < 0.001), higher
serum creatinine (P < 0.001), higher proteinuria (P < 0.001), DR (P ¼ 0.007) and DN (P < 0.001) were independent risk factors for
renal replacement therapy. In addition, older age (P < 0.001), peripheral vascular disease (P ¼ 0.002), higher creatinine
(P ¼ 0.01) and DN (P ¼ 0.015) were independent risk factors for mortality.
Conclusions. The most frequent cause of NDRD is NAS. Elderly patients with microhaematuria and the absence of DR are
the ones at risk for NDRD. Patients with DN presented worse renal prognosis and higher mortality than those with NDRD.
These results suggest that in some patients with diabetes, kidney biopsy may be useful for an accurate renal diagnosis and
subsequently treatment and prognosis
Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study
Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe
The PREDICTS database: a global database of how local terrestrial biodiversity responds to human impacts
Biodiversity continues to decline in the face of increasing anthropogenic pressures
such as habitat destruction, exploitation, pollution and introduction of
alien species. Existing global databases of species’ threat status or population
time series are dominated by charismatic species. The collation of datasets with
broad taxonomic and biogeographic extents, and that support computation of
a range of biodiversity indicators, is necessary to enable better understanding of
historical declines and to project – and avert – future declines. We describe and
assess a new database of more than 1.6 million samples from 78 countries representing
over 28,000 species, collated from existing spatial comparisons of
local-scale biodiversity exposed to different intensities and types of anthropogenic
pressures, from terrestrial sites around the world. The database contains
measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35)
biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains
more than 1% of the total number of all species described, and more than
1% of the described species within many taxonomic groups – including flowering
plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans
and hymenopterans. The dataset, which is still being added to, is
therefore already considerably larger and more representative than those used
by previous quantitative models of biodiversity trends and responses. The database
is being assembled as part of the PREDICTS project (Projecting Responses
of Ecological Diversity In Changing Terrestrial Systems – www.predicts.org.uk).
We make site-level summary data available alongside this article. The full database
will be publicly available in 2015
Prediciendo el número de docentes, médicos y enfermeros en América Latina y el Caribe
Utilizando los datos de diferentes fuentes de información desde 1960, las proyecciones de la población por edad de Naciones Unidas y modelos basados en los cambios observados tanto en los países de la región como en un grupo referencia de la OCDE, los autores estiman el número de empleos de docentes, médicos y enfermeros en 24 países hasta 2040. Asumen que los cambios observados en el pasado en los países de referencia proporcionan información útil sobre lo que se espera en el futuro en América Latina y el Caribe (ALC). Hallan que en el 2040 la región necesitará alrededor de 2.5 veces más médicos y enfermeros y 70% más docentes que en 2017