31,176 research outputs found

    Comparison of different objective functions for parameterization of simple respiration models

    Get PDF
    The eddy covariance measurements of carbon dioxide fluxes collected around the world offer a rich source for detailed data analysis. Simple, aggregated models are attractive tools for gap filling, budget calculation, and upscaling in space and time. Key in the application of these models is their parameterization and a robust estimate of the uncertainty and reliability of their predictions. In this study we compared the use of ordinary least squares (OLS) and weighted absolute deviations (WAD, which is the objective function yielding maximum likelihood parameter estimates with a double exponential error distribution) as objective functions within the annual parameterization of two respiration models: the Q10 model and the Lloyd and Taylor model. We introduce a new parameterization method based on two nonparametric tests in which model deviation (Wilcoxon test) and residual trend analyses (Spearman test) are combined. A data set of 9 years of flux measurements was used for this study. The analysis showed that the choice of the objective function is crucial, resulting in differences in the estimated annual respiration budget of up to 40%. The objective function should be tested thoroughly to determine whether it is appropriate for the application for which the model will be used. If simple models are used to estimate a respiration budget, a trend test is essential to achieve unbiased estimates over the year. The analyses also showed that the parameters of the Lloyd and Taylor model are highly correlated and difficult to determine precisely, thereby limiting the physiological interpretability of the parameter

    A Comparison of Methodologies for Valuing Decreased Health Effects from Wildfire Smoke

    Get PDF
    Wildfire seasons are becoming longer and more intense throughout the world, making it increasingly important to monetize the full damages caused by wildfires when analyzing various fire management policies. We estimate the economic costs of the health effects associated with exposure to wildfire smoke using a simple cost of illness approach and for the first time to our knowledge we estimate willingness-to-pay (WTP) for a decrease in symptom days from wildfire smoke using the contingent valuation method and the averting behavior method. Comparing estimates across all three common approaches for estimating the economic cost of exposure to an air pollutant is an important contribution to the literature. This study uses data from the largest wildfire in Los Angeles County’s modern history, the Station Fire of 2009. Our results show that a simple cost of illness estimate is about 3perdayofsymptoms,theavertingbehaviormethodresultsinaWTPvalueof3 per day of symptoms, the averting behavior method results in a WTP value of 43 or 94toavoidonedayofwildfiresmokeinducedsymptomdays,dependingonthemodelused,andthecontingentvaluationmethodresultsinaWTPestimateof94 to avoid one day of wildfire-smoke induced symptom days, depending on the model used, and the contingent valuation method results in a WTP estimate of 74 - $98 to avoid one day of wildfire-smoke induced symptom days, depending on model specification.averting behavior method, contingent valuation method, cost of illness, wildfire smoke, health, morbidity, Environmental Economics and Policy, Health Economics and Policy, Q,

    Discrimination techniques employing both reflective and thermal multispectral signals

    Get PDF
    Recent improvements in remote sensor technology carry implications for data processing. Multispectral line scanners now exist that can collect data simultaneously and in registration in multiple channels at both reflective and thermal (emissive) wavelengths. Progress in dealing with two resultant recognition processing problems is discussed: (1) More channels mean higher processing costs; to combat these costs, a new and faster procedure for selecting subsets of channels has been developed. (2) Differences between thermal and reflective characteristics influence recognition processing; to illustrate the magnitude of these differences, some explanatory calculations are presented. Also introduced, is a different way to process multispectral scanner data, namely, radiation balance mapping and related procedures. Techniques and potentials are discussed and examples presented

    Do student nurses feel a lack of comfort in providing support for Lesbian, Gay, Bisexual or Questioning adolescents: what factors influence their comfort level?

    Get PDF
    Aim: The aim of this study was to find out if student nurses feel comfortable in caring by providing support for Lesbian, Gay, Bisexual or Questioning adolescents and what factors influence their level of comfort. Background: Research indicates that nurses and nursing students experience varying levels of comfort when caring for adults who are Lesbian, Gay, Bisexual or Questioning: adult patients feel that nurse’s attitudes change towards them once they disclose their sexuality. There has been minimal research to date on nursing attitudes to working with adolescents who are Lesbian, Gay, Bisexual or Questioning. Design Both quantitative and qualitative methods were used in this descriptive study. Questionnaires were completed by 152 nursing students and 9 took part in semi-structured focus groups. Method: A two way ANOVA was used to analyse the questionnaires. Thematic analysis was used to identify the themes arising from the focus groups. Data was collected between August 2013 and July 2014. Results/Findings: The results and findings of the study were that student nurse’s felt discomfort in providing support; due to a lack of knowledge of Lesbian, Gay or Bisexual sexuality, personal and religious beliefs and the perceptions of others. However, all students indicated they had a positive attitude towards Lesbian, Gay, Bisexual and Questioning adolescents. Conclusion: More needs to be done to raise self-awareness and improve the level of knowledge in relation to Lesbian, Gay and Bisexual issues amongst student nurses. Educational institutions and practice areas need to recognize this fact and reflect this in their educational programmes

    Sensitivity of orbiting JEM-EUSO to large-scale cosmic-ray anisotropies

    Full text link
    The two main advantages of space-based observation of extreme-energy (1019\gtrsim 10^{19}~eV) cosmic-rays (EECRs) over ground-based observatories are the increased field of view, and the all-sky coverage with nearly uniform systematics of an orbiting observatory. The former guarantees increased statistics, whereas the latter enables a partitioning of the sky into spherical harmonics. We have begun an investigation, using the spherical harmonic technique, of the reach of \J\ into potential anisotropies in the extreme-energy cosmic-ray sky-map. The technique is explained here, and simulations are presented. The discovery of anisotropies would help to identify the long-sought origin of EECRs.Comment: 7 pages, 6 figures. To appear in the proceedings of the Cosmic Ray Anisotropy Workshop, Madison Wisconsin, September 201

    On the analytic solution of the pairing problem: one pair in many levels

    Get PDF
    We search for approximate, but analytic solutions of the pairing problem for one pair of nucleons in many levels of a potential well. For the collective energy a general formula, independent of the details of the single particle spectrum, is given in both the strong and weak coupling regimes. Next the displacements of the solutions trapped in between the single particle levels with respect to the unperturbed energies are explored: their dependence upon a suitably defined quantum number is found to undergo a transition between two different regimes.Comment: 30 pages, AMS Latex, 8 figures. Submitted to Phys. Rev.

    Nano-scale analysis of titanium dioxide fingerprint-development powders

    Get PDF
    Titanium dioxide based powders are regularly used in the development of latent fingerprints on dark surfaces. For analysis of prints on adhesive tapes, the titanium dioxide is suspended in a surfactant and used in the form of a small particle reagent (SPR). Analysis of commercially available products shows varying levels of effectiveness of print development, with some powders adhering to the background as well as the print. Scanning electron microscopy (SEM) images of prints developed with different powders show a range of levels of aggregation of particles. Analytical transmission electron microscopy (TEM) of the fingerprint powder shows TiO2 particles with a surrounding coating, tens of nanometres thick, consisting of Al and Si rich material. X ray photoelectron spectroscopy (XPS) is used to determine the composition and chemical state of the surface of the powders; with a penetration depth of approximately 10nm, this technique demonstrates differing Ti: Al: Si ratios and oxidation states between the surfaces of different powders. Levels of titanium detected with this technique demonstrate variation in the integrity of the surface coating. The thickness, integrity and composition of the Al/Si-based coating is related to the level of aggregation of TiO2 particles and efficacy of print development

    The many levels pairing Hamiltonian for two pairs

    Full text link
    We address the problem of two pairs of fermions living on an arbitrary number of single particle levels of a potential well (mean field) and interacting through a pairing force. The associated solutions of the Richardson's equations are classified in terms of a number vlv_l, which reduces to the seniority vv in the limit of large values of the pairing strength GG and yields the number of pairs not developing a collective behaviour, their energy remaining finite in the GG\to\infty limit. We express analytically, through the moments of the single particle levels distribution, the collective mode energy and the two critical values Gcr+G_{\rm cr}^{+} and GcrG_{\rm cr}^{-} of the coupling which can exist on a single particle level with no pair degeneracy. Notably Gcr+G_{\rm cr}^{+} and GcrG_{\rm cr}^{-} merge when the number of single particle levels goes to infinity, where they coincide with the GcrG_{\rm cr} (when it exists) of a one pair system, not envisioned by the Richardson theory. In correspondence of GcrG_{\rm cr} the system undergoes a transition from a mean field to a pairing dominated regime. We finally explore the behaviour of the excitation energies, wave functions and pair transfer amplitudes finding out that the former, for G>GcrG>G_{\rm cr}^{-}, come close to the BCS predictions, whereas the latter display a divergence at GcrG_{\rm cr}, signaling the onset of a long range off-diagonal order in the system.Comment: 35 pages, 6 figures, 2 tables, to be published in EPJ

    Body mass index and age affect Three-Factor Eating Questionnaire scores in male subjects

    Get PDF
    This cross-sectional analysis evaluated the effect of age and body mass index (BMI) on Three-Factor Eating Questionnaire scores in males. Subjects (n = 60) were recruited according to BMI status. Each completed the 51-item Three-Factor Eating Questionnaire. The group was split at the median age to produce a "younger" and "older" group for statistical analysis. A 2-way between-groups analysis of variance revealed a significant main effect of BMI on disinhibition (P = .003) and hunger (P = .041) with higher levels found in overweight males compared to healthy-weight counterparts. A significant main effect of age on hunger (P = .046) demonstrated older males were less susceptible to hunger than younger males. These insights provide a better understanding of eating behavior across the male life cycle and may assist health professionals to better guide men in weight management in the light of rising overweight/obesity. (c) 2009 Elsevier Inc. All rights reserved
    corecore