1,124 research outputs found
Surface Localization of Buried III–V Semiconductor Nanostructures
In this work, we study the top surface localization of InAs quantum dots once capped by a GaAs layer grown by molecular beam epitaxy. At the used growth conditions, the underneath nanostructures are revealed at the top surface as mounding features that match their density with independence of the cap layer thickness explored (from 25 to 100 nm). The correspondence between these mounds and the buried nanostructures is confirmed by posterior selective strain-driven formation of new nanostructures on top of them, when the distance between the buried and the superficial nanostructures is short enough (d = 25 nm)
Weather Files for the Calibration of Building Energy Models
In the fight against climate change, energy modeling is a key tool used to analyze the performance of proposed energy conservation measures for buildings. Studies on the integration of photovoltaic energy in buildings must use calibrated building energy models, as only with them is the demand curve real, and the savings obtained at the self-consumption level, energy storage in the building, or feed into the grid are accurate. The adjustment process of a calibrated model depends on aspects inherent to the building properties (envelope parameters, internal loads, use schedules) as well as external to them (weather, ground properties, etc.). Naturally, the uncertainty of each is essential to obtaining good results. As for the meteorological data, it is preferable to use data from a weather station located in the building or its surroundings, although this is not always possible due to the cost of the initial investment and its maintenance. As a result, weather stations with public access to their data, such as those located at airports or specific locations in cities, are largely used to perform calibrations of building energy models, making it challenging to converge the simulated model with measured data. This research sheds light on how this obstacle can be overcome by using weather data provided by a third-party company, bridging the gap between reality and energy models. For this purpose, calibrations of the two buildings proposed in Annex 58 were performed with different weather configurations, using the mean absolute error (MAE) uncertainty index and Spearman’s rank correlation coefficient (rho) as comparative measures. An optimal and cost-effective solution was found as an alternative to an on-site weather station, based on the use of a single outdoor temperature sensor in combination with third-party weather data, achieving a robust and reliable building energy model
Body composition, nutritional profile and muscular fitness affect bone health in a sample of schoolchildren from Colombia: The Fuprecol Study
This is the final version of the article. Available from the publisher via the DOI in this record.The objective of the present study is to investigate the relationships between body
composition, nutritional profile, muscular fitness (MF) and bone health in a sample of children
and adolescents from Colombia. Participants included 1118 children and adolescents (54.6% girls).
Calcaneal broadband ultrasound attenuation (c-BUA) was obtained as a marker of bone health.
Body composition (fat mass and lean mass) was assessed using bioelectrical impedance analysis.
Furthermore height, weight, waist circumference and Tanner stage were measured and body mass
index (BMI) was calculated. Standing long-jump (SLJ) and isometric handgrip dynamometry were
used respectively as indicators of lower and upper body muscular fitness. A muscular index score
was also computed by summing up the standardised values of both SLJ and handgrip strength.
Dietary intake and degree of adherence to the Mediterranean diet were assessed by a 7-day recall
questionnaire for food frequency and the Kidmed questionnaire. Poor bone health was considered
using a z-score cut off of ≤−1.5 standard deviation. Once the results were adjusted for age and
Tanner stage, the predisposing factors of having a c-BUA z-score ≤−1.5 standard deviation included
being underweight or obese, having an unhealthy lean mass, having an unhealthy fat mass, SLJ
performance, handgrip performance, and unhealthy muscular index score. In conclusion, body
composition (fat mass and lean body mass) and MF both influenced bone health in a sample of
children and adolescents from Colombia. Thus promoting strength adaptation and preservation in
Colombian youth will help to improve bone health, an important protective factor against osteoporosis
in later life.: We would like to acknowledge to Bogota District Education Department for supporting data
collection for this study. The authors also thank the participating Bogota District students, teachers, schools, and
staff. The “FUPRECOL Study” was possible given the financial support provided by the Instituto Colombiano
para el Desarrollo de la Ciencia y la Tecnología “Francisco José de Caldas” COLCIENCIAS (Contract Number
671-2014 Code 122265743978). Also, during the completion of this paper, AG-H was visiting researchers at
the University of Rosario (CEMA, Bogotá, Colombia), supported with grants awarded by Proyectos Basales y
Vicerrectoría de Investigación, Desarrollo e Innovación” (Universidad de Santiago de Chile, USACH)
Enhanced error estimator based on a nearly equilibrated moving least squares recovery technique for FEM and XFEM
In this paper a new technique aimed to obtain accurate estimates of the error
in energy norm using a moving least squares (MLS) recovery-based procedure is
presented. We explore the capabilities of a recovery technique based on an
enhanced MLS fitting, which directly provides continuous interpolated fields,
to obtain estimates of the error in energy norm as an alternative to the
superconvergent patch recovery (SPR). Boundary equilibrium is enforced using a
nearest point approach that modifies the MLS functional. Lagrange multipliers
are used to impose a nearly exact satisfaction of the internal equilibrium
equation. The numerical results show the high accuracy of the proposed error
estimator
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How do markets manage water resources? An experiment
We experimentally test how a private monopoly, a duopoly and a public utility allocate water of differing qualities to households and farmers. Most of our results are in line with the theoretical predictions. Overexploitation of the resources is observed independently of the market structure. Stock depletion for the public utility is the fastest, followed by the private duopoly and private monopoly. On the positive aspects of centralized public management, we find that the average quality to price ratio offered by the public monopoly is substantially higher than that offered by the private monopoly or duopoly
Loss of slc39a14 causes simultaneous manganese hypersensitivity and deficiency in zebrafish
Manganese neurotoxicity is a hallmark of Hypermanganesemia with Dystonia 2, an inherited manganese transporter defect caused by mutations in SLC39A14. To identify novel potential targets of manganese neurotoxicity we performed transcriptome analysis of slc39a14-/- mutant zebrafish unexposed and exposed to MnCl2. Differentially expressed genes mapped to the central nervous system and eye, and pathway analysis suggested that calcium dyshomeostasis and activation of the unfolded protein response are key features of manganese neurotoxicity. Consistent with this interpretation, MnCl2 exposure led to decreased whole animal calcium levels, locomotor defects and changes in neuronal activity within the telencephalon and optic tectum. In accordance with reduced tectal activity, slc39a14-/- zebrafish showed changes in visual phototransduction gene expression, absence of visual background adaptation and a diminished optokinetic reflex. Finally, numerous differentially expressed genes in mutant larvae normalised upon MnCl2 treatment indicating that, in addition to neurotoxicity, manganese deficiency is present either subcellularly or in specific cells or tissues. Overall, we assembled a comprehensive set of genes that mediate manganese-systemic responses and found a highly correlated and modulated network associated with calcium dyshomeostasis and cellular stress
Classical kinetic energy, quantum fluctuation terms and kinetic-energy functionals
We employ a recently formulated dequantization procedure to obtain an exact
expression for the kinetic energy which is applicable to all kinetic-energy
functionals. We express the kinetic energy of an N-electron system as the sum
of an N-electron classical kinetic energy and an N-electron purely quantum
kinetic energy arising from the quantum fluctuations that turn the classical
momentum into the quantum momentum. This leads to an interesting analogy with
Nelson's stochastic approach to quantum mechanics, which we use to conceptually
clarify the physical nature of part of the kinetic-energy functional in terms
of statistical fluctuations and in direct correspondence with Fisher
Information Theory. We show that the N-electron purely quantum kinetic energy
can be written as the sum of the (one-electron) Weizsacker term and an
(N-1)-electron kinetic correlation term. We further show that the Weizsacker
term results from local fluctuations while the kinetic correlation term results
from the nonlocal fluctuations. For one-electron orbitals (where kinetic
correlation is neglected) we obtain an exact (albeit impractical) expression
for the noninteracting kinetic energy as the sum of the classical kinetic
energy and the Weizsacker term. The classical kinetic energy is seen to be
explicitly dependent on the electron phase and this has implications for the
development of accurate orbital-free kinetic-energy functionals. Also, there is
a direct connection between the classical kinetic energy and the angular
momentum and, across a row of the periodic table, the classical kinetic energy
component of the noninteracting kinetic energy generally increases as Z
increases.Comment: 10 pages, 1 figure. To appear in Theor Chem Ac
A 1.3 mm SMA Survey of 29 Variable Young Stellar Objects
Young stellar objects (YSOs) may undergo periods of active accretion (outbursts), during which the protostellar accretion rate is temporarily enhanced by a few orders of magnitude. Whether or not these accretion outburst YSOs possess similar dust/gas reservoirs to each other, and whether or not their dust/gas reservoirs are similar as quiescent YSOs, are issues not yet clarified. The aim of this work is to characterize the millimeter thermal dust emission properties of a statistically significant sample of long and short duration accretion outburst YSOs (i.e., FUors and EXors) and the spectroscopically identified candidates of accretion outbursting YSOs (i.e., FUor-like objects). We have carried out extensive Submillimeter Array (SMA) observations mostly at 225 GHz (1.33 mm) and 272 GHz (1.10 mm), from 2008 to 2017. We covered accretion outburst YSOs located at 3- significance. Detected sources except for the two cases of V883 Ori and NGC 2071 MM3 were observed with 1 angular resolution. Overall our observed targets show a systematically higher millimeter luminosity distribution than those of the 0.3 Class II YSOs in the nearby (400 pc) low-mass star-forming molecular clouds (e.g., Taurus, Lupus, Upp Scorpio, and Chameleon I). In addition, at 1 mm our observed confirmed binaries or triple-system sources are systematically fainter than the rest of the sources even though their 1 mm fluxes are broadly distributed. We may have detected 30-60\% millimeter flux variability from V2494 Cyg and V2495 Cyg, from the observations separated by 1 year
Incretins in patients with rheumatoid arthritis
Background: The precise mechanism linking systemic inflammation with insulin resistance (IR) in rheumatoid arthritis (RA) remains elusive. In the present study, we determined whether the incretin-insulin axis and incretin effect are disrupted in patients with RA and if they are related to the IR found in these patients. Methods: We conducted a cross-sectional study that encompassed 361 subjects without diabetes, 151 patients with RA, and 210 sex-matched control subjects. Insulin, C-peptide, glucagon-like peptide-1 (GLP-1), gastric inhibitory polypeptide (GIP), dipeptidyl peptidase 4 (DPP-4) soluble form, and IR indexes by homeostatic model assessment (HOMA2) were assessed. A multivariable analysis adjusted for IR-related factors was performed. Additionally, ten patients and ten control subjects underwent a 566-kcal meal test so that we could further study the postprandial differences of these molecules between patients and control subjects. Results: Insulin, C-peptide, and HOMA2-IR indexes were higher in patients than in control subjects. This was also the case for GLP-1 (0.49 ± 1.28 vs. 0.71 ± 0.22 ng/ml, p = 0.000) and GIP (0.37 ± 0.40 vs. 1.78 ± 0.51 ng/ml, p = 0.000). These differences remained significant after multivariable adjustment including glucocorticoid intake. Disease Activity Score in 28 joints with erythrocyte sedimentation rate (? coefficient 46, 95% CI 6?87, p = 0.026) and Clinical Disease Activity Index (? coefficient 7.74, 95% CI 1.29?14.20, p = 0.019) were associated with DPP-4 serum levels. GLP-1 positively correlated with ?-cell function (HOMA2 of ?-cell production calculated with C-peptide) in patients but not in control subjects (interaction p = 0.003). The meal test in patients with RA revealed a higher total and late response AUC for glucose response, a later maximal response of C-peptide, and a flatter curve in GIP response. Conclusions: The incretin-insulin axis, both during fasting and postprandial, is impaired in patients with RA.This work was supported by grants from the Spanish Ministry of Health,
Subdirección General de Evaluación y Fomento de la Investigación, Plan
Estatal de Investigación Científica y Técnica y de Innovación 2013–2016
Instituto de Salud Carlos III [ISCIII] PI14/00394) and by the Fondo Europeo de
Desarrollo Regional (FEDER) (to IFA). The research of MAGG was supported
by European Union FEDER funds and by the “Fondo de Investigación
Sanitaria” (grants PI06/0024, PS09/00748, PI12/00060, and PI15/00525) of the
Instituto de Salud Carlos III (ISCIII; Spanish Health Ministry). The research of
MAGG was also partially supported by RETICS Programs RD12/0009 (RIER)
and RD12/0009/0013 from the ISCIII (Spanish Health Ministry)
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