1,096 research outputs found
Optimisation of the bidding strategy for wind power trading
The optimal bidding strategy for trading electricity from a wind farm is not always clear. This paper outlines a method for predicting whether the market will be long or short and uses this information to select the best quantile regression for the current market conditions. Results from a simulation with a 2.5MW turbine produced a savings of over £2,000 compared to using only a P50 forecaster
Psychometric Analysis of the JSPE Nursing Student Version R: Comparison of Senior BSN Students and Medical Students Attitudes toward Empathy in Patient Care
Background. Empathic communication skills are critical to providing high-quality nursing care to holistically understand the patient's perspective. A survey research design was used to address the research questions discussed in this study. Data consisted of responses from nursing students attending accredited programs in the southeastern United Sates using the Jefferson Scale of Physician Empathy Nursing Student Version R (JSPE-R).
Findings. Comparisons of the total scores from JSPE Versions S and R yielded similar means and standard deviations with 115 and 114.57, respectively, and standard deviations of 10 and 10.94, respectively. The results of a one-sample t-test failed to render statistical significance (t = −1.22, P = .224), indicating that the overall attitudes of nursing students and medical students are similar. The 25th, 50th, and 75th percentiles and overall instrument reliability were also comparable.
Conclusions. This paper supports the emergence of alternative factor analysis structures as applied to nursing students through statistical progression from exploratory factor analysis to confirmatory structures. Implications for practice explore the utility of empathy instruments in nurse education, such as empathy progression through curriculum. As nursing educators, the utility of development of instruments to measure effectiveness of teaching strategies and pedagogy for empathy enhancement in practice is important
Application of Cryopreserved Human Hepatocytes in Trichloroethylene Risk Assessment: Relative Disposition of Chloral Hydrate to Trichloroacetate and Trichloroethanol
BACKGROUND: Trichloroethylene (TCE) is a suspected human carcinogen and a common ground-water contaminant. Chloral hydrate (CH) is the major metabolite of TCE formed in the liver by cytochrome P450 2E1. CH is metabolized to the hepatocarcinogen trichloroacetate (TCA) by aldehyde dehydrogenase (ALDH) and to the noncarcinogenic metabolite trichloroethanol (TCOH) by alcohol dehydrogenase (ADH). ALDH and ADH are polymorphic in humans, and these polymorphisms are known to affect the elimination of ethanol. It is therefore possible that polymorphisms in CH metabolism will yield subpopulations with greater than expected TCA formation with associated enhanced risk of liver tumors after TCE exposure. METHODS: The present studies were undertaken to determine the feasibility of using commercially available, cryogenically preserved human hepatocytes to determine simultaneously the kinetics of CH metabolism and ALDH/ADH genotype. Thirteen human hepatocyte samples were examined. Linear reciprocal plots were obtained for 11 ADH and 12 ALDH determinations. RESULTS: There was large interindividual variation in the V(max) values for both TCOH and TCA formation. Within this limited sample size, no correlation with ADH/ALDH genotype was apparent. Despite the large variation in V(max) values among individuals, disposition of CH into the two competing pathways was relatively constant. CONCLUSIONS: These data support the use of cryopreserved human hepatocytes as an experimental system to generate metabolic and genomic information for incorporation into TCE cancer risk assessment models. The data are discussed with regard to cellular factors, other than genotype, that may contribute to the observed variability in metabolism of CH in human liver
Continuous Leg Cycling Ergometry Prescribed at Identical Relative Power Output Elicits Different Physiological Responses Versus Arm Cycle Ergometry
PURPOSE: The aim of this study was to compare physiological and perceptual responses to progressive moderate intensity continuous exercise (MICE) between leg (LCE) and arm cycle ergometry (ACE). METHODS: Seventeen active men and women (age and percent body fat = 26 ± 7 yr and 18 ± 3 %) initially performed graded exercise on each modality to assess maximal oxygen uptake (VO2max) and peak power output (PPO). Using a randomized crossover design, they subsequently performed 45 min of MICE consisting of three 15 min bouts at 20, 40, and 60 % PPO on each modality. Gas exchange data (VO2, VCO2, VE, and respiratory exchange ratio (RER), heart rate (HR), blood lactate concentration (BLa), affective valence, and rating of perceived exertion (RPE) were acquired during each bout. RESULTS: Compared to ACE, LCE revealed significantly higher (p \u3c 0.05) peak (94 ± 6 vs. 88 ± 9 %HRmax, d = 0.81) and mean HR (73 ± 6 vs. 66 ± 6 %HRmax, d = 1.20) and VO2 (54 ± 5 vs. 50 ± 7 %VO2max, d = 0.68). Time spent above 70 (22 ± 7 vs. 15 ± 8 min, d = 1.03) and 80 %HRmax (15 ± 6 vs. 9 ± 6 min, d = 1.04) was significantly greater with LCE versus ACE. LCE revealed significantly higher BLa versus ACE (5.5 ± 2.0 vs. 4.7 ± 1.5 mM, d = 0.48). CONCLUSIONS: These results exhibit that progressive leg cycling at identical intensities elicits a greater cardiometabolic stimulus than arm ergometry. Moreover, leg cycling leads to greater duration spent at intensities between 70 – 89 %VO2max which may have application to selecting specific exercise modes when prescribing MICE to increase cardiorespiratory fitness. Lastly, use of %PPO led to participants being classified in different intensity domains which merits prescribing MICE according to various threshold measures rather than relative intensities acquired from incremental exercise
Larva of the greater wax moth, Galleria mellonella, is a suitable alternative host for studying virulence of fish pathogenic Vibrio anguillarum
Background: Microbial diseases cause considerable economic losses in aquaculture and new infection control measures often rely on a better understanding of pathogenicity. However, disease studies performed in fish hosts often require specialist infrastructure (e.g., aquaria), adherence to strict legislation and do not permit high-throughput approaches; these reasons justify the development of alternative hosts. This study aimed to validate the use of larvae of the greater wax moth (Galleria mellonella) to investigate virulence of the important fish pathogen, Vibrio anguillarum. Results: Using 11 wild-type isolates of V. anguillarum, these bacteria killed larvae in a dose-dependent manner and replicated inside the haemolymph, but infected larvae were rescued by antibiotic therapy. Crucially, virulence correlated significantly and positively in larva and Atlantic salmon (Salmo salar) infection models. Challenge studies with mutants knocked out for single virulence determinants confirmed conserved roles in larva and fish infections in some cases (pJM1 plasmid, rtxA), but not all (empA, flaA, flaE). Conclusions: The G. mellonella model is simple, more ethically acceptable than experiments on vertebrates and, crucially, does not necessitate liquid systems, which reduces infrastructure requirements and biohazard risks associated with contaminated water. The G. mellonella model may aid our understanding of microbial pathogens in aquaculture and lead to the timely introduction of new effective remedies for infectious diseases, while adhering to the principles of replacement, reduction and refinement (3Rs) and considerably reducing the number of vertebrates used in such studies
A prospective study of the sensitivity, specificity and diagnostic performance of soluble intercellular adhesion molecule 1, highly sensitive C-reactive protein, soluble E-selectin and serum amyloid A in the diagnosis of neonatal infection
<p>Abstract</p> <p>Background</p> <p>Diagnosis of neonatal infection is difficult, because of it's non-specific clinical presentation and the lack of reliable diagnostic tests. The purpose of this study was to examine the potential diagnostic value of serum soluble intercellular adhesion molecule-1 (sICAM-1), soluble E-selectin (sE-selectin), highly sensitive C-reactive protein (hsCRP) and serum amyloid A (SAA) measurements, both individually and in combination in the setting of a neonatal intensive care unit.</p> <p>Methods</p> <p>219 consecutive serum samples were taken from 149 infants undergoing sepsis work up in a neonatal intensive care unit. Clinical diagnosis was established in a prospective manner, blind to the results of the study measurements. Infants were classified by an experienced paediatrician as infected or not-infected, one week after presentation. Classification was based on clinical presentation, routine laboratory and radiological investigations and response to therapy. The infected group were sub-classified as (a) culture positive infection or (b) culture negative infection. sICAM-1, sE-selectin, hsCRP and SAA levels were determined from stored serum samples after diagnosis was established. Further sub-group analysis of results was undertaken according to early or late onset of infection and preterm or term status. Statistical analysis utilised Mann Whitney U test and ROC curve analysis.</p> <p>Results</p> <p>There were significantly increased serum levels of sICAM-1, hsCRP, E selectin (p < 0.001) and SAA (p = 0.004) in infected infants compared with non-infected. ROC curve analysis indicated area under the curve values of 0.79 (sICAM-1), 0.73 (hsCRP), 0.72 (sE-selectin) and 0.61 (SAA). ROC curve analysis also defined optimum diagnostic cut-off levels for each measurement. The performance characteristics of sICAM-1, hsCRP and sE-selectin included a high negative predictive value (NPV) for culture positive infection and this was enhanced by combination of all 4 measurements. Clinical subgroup analysis suggested particularly high NPV for early onset symptoms, however further studies are required to elucidate this finding.</p> <p>Conclusions</p> <p>All four study measurements demonstrated some diagnostic value for neonatal infection however sICAM-1, hsCRP and sE-selectin demonstrated the highest NPV individually. The optimum diagnostic cut off level for hsCRP measurement in this study was much lower than currently used in routine clinical practice. Use of a combination of measurements enhanced diagnostic performance, demonstrating sensitivity of 90.3% and NPV of 91.3%. This study suggests there may be value in use of several of these markers, individually and in combination to assist in excluding neonatal infection. Further work is needed to confirm a specific role in the exclusion of early onset infection.</p
Rational functions: an alternative approach to asset pricing
This paper shows that asset prices are linear polynomials of various underlying explanatory factors and asset returns being ratios of these polynomials, are rational functions that do not add linearly when averaging. Hence, average returns should be modeled based on stock prices. However, continuous returns may be treated as approximately linear across time and modeled directly. Our new Rational Function (RF) models, empirically outperform the traditional asset pricing models like the Capital Asset Pricing Model (CAPM) and the Fama–French three and five-factor models for both average and continuous returns. Moreover, the RF theory also provides a model to estimate the asset volumes. The average change in asset volumes together with average returns provide the estimates for average change in market values of assets. Thus, the RF model approach can be used to select assets that provide either highest returns for profit maximization or highest change in market values for wealth maximization for given levels of risk
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