3,655 research outputs found

    Nebular abundances of southern symbiotic stars

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    We have calculated relative elemental abundances for a sample of 43 symbiotic stars. Helium abundances and the relative elemental abundances N/O, Ne/O, Ar/O were derived from new spectra collected in the optical range through low dispersion spectroscopy. The He ionic abundances were derived taking into account self-absorption effects in Balmer lines. We found that the symbiotic stars in the galactic bulge have heavy element abundances showing the same wide distribution as other bulge objects. In the galactic disk, the symbiotic stars follow the abundance gradient as derived from different kinds of objects.Comment: 12 pages, 6 figures, A&A - accepte

    Contrast Enhancement of Optical Coherence Tomography Images Using Branched Gold Nanoparticles

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    We propose the use of branched gold nanoparticles (B-GNPs) as a contrast agent for optical coherence tomography (OCT) imaging. Our results show that even when the central source of our OCT (1325 nm) is too far from the maximum peak of the plasmon resonance, branched nanoparticles scatter light very efficiently at this wavelength. B-GNPs were tested as a contrast agent in water and agarose-TiO2 tissue phantoms; the estimated increments in contrast were 9.19 dB and 15.07 dB for branched nanoparticles in water with concentrations of 2.2×109 NPs/mL and 6.6×109 NPs/mL, respectively, while for agarose-TiO2 tissue phantoms the estimated value was 3.17 dB. These results show the promising application of B-GNPs as a contrast agent for tissue imaging using OCT, not only for sources at 1325 nm but also at other central wavelengths located between 800 and 1000 nm

    Estrategia y desarrollo del simulador de negocios Capsim

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    En este trabajo se recopila la experiencia en el simulador de negocios Capsim, en el cual se manejó una empresa de sensores electrónicos. Se supervisó desde su desarrollo hasta la puesta en el mercado y se tomaron decisiones para cada año operativo dentro del simulador. Se trabajó en la administración de las áreas de diseño, investigación, desarrollo, mercadotécnica, producción, recursos humanos y finanzas

    Economic Feasibility of Passive Strate gies for Energy Efficient Envelopes of Mass-Built Housing in Hot -Dry Climate

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    The authors thank the Autonomous University of Baja California and the Master and Doctorate program in Architecture, Urbanism and Design (MyDAUD) for the support provided to carry out this study, the National Council of Science and Technology (CONACyT) for the scholarship provided for the completion of master’s degree studies, as well as the RUBA construction company.The building and construction industry represents 36% of the world’s final energy use and 39% of carbon emissions, while the residential sector is responsible for 22% of total energy consumption and 17% of carbon emissions. Therefore, energy consumption reduction measures are required by this sector, without affecting the living conditions of its occupants. In Baja California, Mexico, the more commonly used construction systems in mass-built housing are concrete block walls and cast in place insulated reinforced concrete roof deck. These systems negatively affect comfort conditions, especially in hot summer periods, and therefore increase energy consumption, particularly in areas with an hot-dry climate, such as Mexicali, Baja California. The objective of this article is to determine the cost-benefit of two passive design strategies applied in the housing envelope, which are thermal insulation and ventilated facade. A commercial model of mass-built housing was taken as a benchmark case. Building energy simulations were carried out with the Design Builder® program, whereby the performance of the house was evaluated without passive design strategies (benchmark case) and with applied strategies, that is, variations in thickness and position of the materials that make up the layers of the walls and roof. Additionally, the net present value (NPV) criterion was used to obtain the costs and benefits of the design strategies. The results show the differences in cooling demand, indoor operative temperature, and the total costs, in Mexican pesos, of the application of the strategies; the results show that there are significant energy savings, which contribute to reducing carbon emissions to the environment and provide economic savings for the user

    A personalized intervention to prevent depression in primary care based on risk predictive algorithms and decision support systems: protocol of the e-predictD study

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    The predictD is an intervention implemented by general practitioners (GPs) to prevent depression, which reduced the incidence of depression-anxiety and was cost-effective. The e-predictD study aims to design, develop, and evaluate an evolved predictD intervention to prevent the onset of major depression in primary care based on Information and Communication Technologies, predictive risk algorithms, decision support systems (DSSs), and personalized prevention plans (PPPs). A multicenter cluster randomized trial with GPs randomly assigned to the e-predictD intervention + care-as-usual (CAU) group or the active-control + CAU group and 1-year follow-up is being conducted. The required sample size is 720 non-depressed patients (aged 18–55 years), with moderate-to-high depression risk, under the care of 72 GPs in six Spanish cities. The GPs assigned to the e-predictD-intervention group receive brief training, and those assigned to the control group do not. Recruited patients of the GPs allocated to the e-predictD group download the e-predictD app, which incorporates validated risk algorithms to predict depression, monitoring systems, and DSSs. Integrating all inputs, the DSS automatically proposes to the patients a PPP for depression based on eight intervention modules: physical exercise, social relationships, improving sleep, problem-solving, communication skills, decision-making, assertiveness, and working with thoughts. This PPP is discussed in a 15-min semi-structured GP-patient interview. Patients then choose one or more of the intervention modules proposed by the DSS to be self-implemented over the next 3 months. This process will be reformulated at 3, 6, and 9 months but without the GP–patient interview. Recruited patients of the GPs allocated to the control-group+CAU download another version of the e-predictD app, but the only intervention that they receive via the app is weekly brief psychoeducational messages (active-control group). The primary outcome is the cumulative incidence of major depression measured by the Composite International Diagnostic Interview at 6 and 12 months. Other outcomes include depressive symptoms (PHQ-9) and anxiety symptoms (GAD-7), depression risk (predictD risk algorithm), mental and physical quality of life (SF-12), and acceptability and satisfaction (‘e-Health Impact' questionnaire) with the intervention. Patients are evaluated at baseline and 3, 6, 9, and 12 months. An economic evaluation will also be performed (cost-effectiveness and cost-utility analysis) from two perspectives, societal and health systems.Trial registrationClinicalTrials.gov, identifier: NCT03990792

    Towards a new quality-controlled daily climate dataset for the Pyrenees, 1950-2015

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    Póster presentado en: EMS Annual Meeting: European Conference for Applied Meteorology and Climatology celebrado del 4 al 8 de septiembre de 2017 en Dublin, IrlandaPrevious works using lower-density datasets addressed warming rates with slight differences depending on the season and diffuse trends for precipitation. New and more accurate results in spatio-temporal variations of these climate variables are expected on behalf the development of the CLIM’PY project, which aims to: i) detect past trends with instrumental data and, ii) estimate future behaviours in climatic variables based on projected scenarios. Temperature, precipitation and snow cover in the Pyrenees will be analysed within the framework of the project. In this communication, we present the methodology we will follow to conduct the quality control analysis of daily temperature and precipitation, which will include 673 stations of Spain, France and Andorra, covering the period 1950-2015

    All-particle cosmic ray energy spectrum measured by the HAWC experiment from 10 to 500 TeV

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    We report on the measurement of the all-particle cosmic ray energy spectrum with the High Altitude Water Cherenkov (HAWC) Observatory in the energy range 10 to 500 TeV. HAWC is a ground based air-shower array deployed on the slopes of Volcan Sierra Negra in the state of Puebla, Mexico, and is sensitive to gamma rays and cosmic rays at TeV energies. The data used in this work were taken from 234 days between June 2016 to February 2017. The primary cosmic-ray energy is determined with a maximum likelihood approach using the particle density as a function of distance to the shower core. Introducing quality cuts to isolate events with shower cores landing on the array, the reconstructed energy distribution is unfolded iteratively. The measured all-particle spectrum is consistent with a broken power law with an index of 2.49±0.01-2.49\pm0.01 prior to a break at (45.7±0.1(45.7\pm0.1) TeV, followed by an index of 2.71±0.01-2.71\pm0.01. The spectrum also respresents a single measurement that spans the energy range between direct detection and ground based experiments. As a verification of the detector response, the energy scale and angular resolution are validated by observation of the cosmic ray Moon shadow's dependence on energy.Comment: 16 pages, 11 figures, 4 tables, submission to Physical Review

    Observation of the Crab Nebula with the HAWC Gamma-Ray Observatory

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    The Crab Nebula is the brightest TeV gamma-ray source in the sky and has been used for the past 25 years as a reference source in TeV astronomy, for calibration and verification of new TeV instruments. The High Altitude Water Cherenkov Observatory (HAWC), completed in early 2015, has been used to observe the Crab Nebula at high significance across nearly the full spectrum of energies to which HAWC is sensitive. HAWC is unique for its wide field-of-view, nearly 2 sr at any instant, and its high-energy reach, up to 100 TeV. HAWC's sensitivity improves with the gamma-ray energy. Above \sim1 TeV the sensitivity is driven by the best background rejection and angular resolution ever achieved for a wide-field ground array. We present a time-integrated analysis of the Crab using 507 live days of HAWC data from 2014 November to 2016 June. The spectrum of the Crab is fit to a function of the form ϕ(E)=ϕ0(E/E0)αβln(E/E0)\phi(E) = \phi_0 (E/E_{0})^{-\alpha -\beta\cdot{\rm{ln}}(E/E_{0})}. The data is well-fit with values of α=2.63±0.03\alpha=2.63\pm0.03, β=0.15±0.03\beta=0.15\pm0.03, and log10(ϕ0 cm2 s TeV)=12.60±0.02_{10}(\phi_0~{\rm{cm}^2}~{\rm{s}}~{\rm{TeV}})=-12.60\pm0.02 when E0E_{0} is fixed at 7 TeV and the fit applies between 1 and 37 TeV. Study of the systematic errors in this HAWC measurement is discussed and estimated to be ±\pm50\% in the photon flux between 1 and 37 TeV. Confirmation of the Crab flux serves to establish the HAWC instrument's sensitivity for surveys of the sky. The HAWC survey will exceed sensitivity of current-generation observatories and open a new view of 2/3 of the sky above 10 TeV.Comment: Submitted 2017/01/06 to the Astrophysical Journa
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