793 research outputs found

    Wind farm capital cost regression model for accurate life cycle cost estimation

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    Various studies over the last decade have attempted to forecast capital cost of wind power. The main assumption underpinning these models is that cost reductions will accrue indefinitely from technological learning over time. In this paper a regression model is proposed for wind farm capital cost which is based on commodities price and water depth rather than technological learning. With greater simplicity and certainty in the theoretical foundations of such a model, it is possible to gain realistic estimates of wind turbine capital cost. Such pragmatic and well-reasoned output is needed so that wind farm developers can understand their future risk exposure to price fluctuations in capital cost of plant

    Continuous Leg Cycling Ergometry Prescribed at Identical Relative Power Output Elicits Different Physiological Responses Versus Arm Cycle Ergometry

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    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

    Virtual orthopaedic teaching during COVID-19 : Zooming around Scotland

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    ACKNOWLEDGEMENTS The authors would like to acknowledge the following SCORE collaborators: Peter SE Davies, Ninewells Hospital, Dundee; Matthew Howell, Queen Elizabeth Hospital, Glasgow; Stuart Goudie, Edinburgh Royal Infirmary; Sarah L Gill, Queen Elizabeth Hospital, Glasgow; Arpit Jariwala, Ninewells Hospital, Dundee and George P Ashcroft, University of Aberdeen.Peer reviewedPublisher PD

    Larva of the greater wax moth, Galleria mellonella, is a suitable alternative host for studying virulence of fish pathogenic Vibrio anguillarum

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    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

    Physiological responses to moderate intensity continuous and high-intensity interval exercise in persons with paraplegia

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    Randomized crossover. To test differences in the duration and magnitude of physiological response to isocaloric moderate intensity continuous (MICE) and high-intensity interval exercise (HIIE) sessions in persons with spinal cord injury (SCI). Academic medical center in Miami, FL, USA. Ten adult men (mean ± s.d.; 39 ± 10 year old) with chronic (13.2 ± 8.8 year) paraplegia (T2-T10) completed a graded exercise test. Then, in a randomized order, participants completed MICE and HIIE for a cost of 120 kcal. MICE was performed at 24.6% PO . During HIIE, exercise was completed in 2 min work and recovery phases at 70%:10% PO . MICE and HIIE were isocaloric (115.9 ± 21.8 and 116.6 ± 35.0 kcal, respectively; p = 0.903), but differed in duration (39.8 ± 4.6 vs 32.2 ± 6.2 min; p < 0.001) and average respiratory exchange ratio (RER; 0.90 ± 0.08 vs 1.01 ± 0.07; p = 0.002). During MICE, a workrate of 24.6 ± 6.7% PO elicited a V̇O of 53.1 ± 6.5% V̇O (10.1 ± 2.2 ml kg  min ). During HIIE, a workrate at 70% PO elicited 88.3 ± 6.7% V̇O (16.9 ± 4.2 ml kg  min ), and 29.4 ± 7.7% of the session was spent at or above 80% V̇O . During HIIE working phase, RER declined from the first to last interval (1.08 ± 0.07 vs 0.98 ± 0.09; p < 0.001), reflecting an initially high but declining glycolytic rate. Compared with MICE, HIIE imposed a greater physiological stimulus while requiring less time to achieve a target caloric expenditure. Thus, exercise intensity might be an important consideration in the tailoring of exercise prescription to address the cardiometabolic comorbidities of SCI

    Physiological responses to moderate intensity continuous and high-intensity interval exercise in persons with paraplegia

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    Study design: Randomized crossover. Objectives: To test differences in the duration and magnitude of physiological response to isocaloric moderate intensity continuous (MICE) and high-intensity interval exercise (HIIE) sessions in persons with spinal cord injury (SCI). Setting: Academic medical center in Miami, FL, USA. Methods: Ten adult men (mean ± s.d.; 39 ± 10 year old) with chronic (13.2 ± 8.8 year) paraplegia (T2–T10) completed a graded exercise test. Then, in a randomized order, participants completed MICE and HIIE for a cost of 120 kcal. MICE was performed at 24.6% PO peak. During HIIE, exercise was completed in 2 min work and recovery phases at 70%:10% PO peak. Results: MICE and HIIE were isocaloric (115.9 ± 21.8 and 116.6 ± 35.0 kcal, respectively; p = 0.903), but differed in duration (39.8 ± 4.6 vs 32.2 ± 6.2 min; p &lt; 0.001) and average respiratory exchange ratio (RER; 0.90 ± 0.08 vs 1.01 ± 0.07; p = 0.002). During MICE, a workrate of 24.6 ± 6.7% PO peak elicited a V̇O 2 of 53.1 ± 6.5% V̇O 2peak (10.1 ± 2.2 ml kg −1 min −1). During HIIE, a workrate at 70% PO peak elicited 88.3 ± 6.7% V̇O 2peak (16.9 ± 4.2 ml kg −1 min −1), and 29.4 ± 7.7% of the session was spent at or above 80% V̇O 2peak. During HIIE working phase, RER declined from the first to last interval (1.08 ± 0.07 vs 0.98 ± 0.09; p &lt; 0.001), reflecting an initially high but declining glycolytic rate. Conclusions: Compared with MICE, HIIE imposed a greater physiological stimulus while requiring less time to achieve a target caloric expenditure. Thus, exercise intensity might be an important consideration in the tailoring of exercise prescription to address the cardiometabolic comorbidities of SCI. </p

    Effects of exercise mode on postprandial metabolism in humans with chronic paraplegia:Exercise and postprandial metabolism in SCI

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    PURPOSE: The purpose of this study was to assess the acute effects of exercise mode and intensity on postprandial macronutrient metabolism.METHODS: Ten healthy men age 39 ± 10 yr with chronic paraplegia (13.2 ± 8.8 yr, ASIA A-C) completed three isocaloric bouts of upper-body exercise and a resting control. After an overnight fast, participants completed circuit resistance exercise (CRE) first and the following conditions in a randomized order, separated by >48 h: i) control (CON), ~45-min seated rest; ii) moderate-intensity continuous exercise (MICE), ~40-min arm cranking at a resistance equivalent to ~30% peak power output (PPO); and iii) high-intensity interval exercise (HIIE), ~30 min arm cranking with resistance alternating every 2 min between 10% PPO and 70% PPO. After each condition, participants completed a mixed-meal tolerance test consisting of a 2510-kJ liquid meal (35% fat, 50% carbohydrate, 15% protein). Blood and expired gas samples were collected at baseline and regular intervals for 150 min after a meal.RESULTS: An interaction (P < 0.001) was observed, with rates of lipid oxidation elevated above CON in HIIE until 60 min after a meal and in CRE at all postprandial time points up to 150 min after a meal. Postprandial blood glycerol was greater in MICE (P = 0.020) and CRE (P = 0.001) compared with CON. Furthermore, nonesterified fatty acid area under the curve had a moderate-to-strong effect in CRE versus MICE and HIIE (Cohen's d = -0.76 and -0.50, respectively).CONCLUSIONS: In persons with paraplegia, high-intensity exercise increased postprandial energy expenditure independent of the energy cost of exercise. Furthermore, exercise combining resistance and endurance modes (CRE) showed the greater effect on postprandial lipid oxidation

    Effects of exercise mode on postprandial metabolism in humans with chronic paraplegia:Exercise and postprandial metabolism in SCI

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    PURPOSE: The purpose of this study was to assess the acute effects of exercise mode and intensity on postprandial macronutrient metabolism.METHODS: Ten healthy men age 39 ± 10 yr with chronic paraplegia (13.2 ± 8.8 yr, ASIA A-C) completed three isocaloric bouts of upper-body exercise and a resting control. After an overnight fast, participants completed circuit resistance exercise (CRE) first and the following conditions in a randomized order, separated by &gt;48 h: i) control (CON), ~45-min seated rest; ii) moderate-intensity continuous exercise (MICE), ~40-min arm cranking at a resistance equivalent to ~30% peak power output (PPO); and iii) high-intensity interval exercise (HIIE), ~30 min arm cranking with resistance alternating every 2 min between 10% PPO and 70% PPO. After each condition, participants completed a mixed-meal tolerance test consisting of a 2510-kJ liquid meal (35% fat, 50% carbohydrate, 15% protein). Blood and expired gas samples were collected at baseline and regular intervals for 150 min after a meal.RESULTS: An interaction (P &lt; 0.001) was observed, with rates of lipid oxidation elevated above CON in HIIE until 60 min after a meal and in CRE at all postprandial time points up to 150 min after a meal. Postprandial blood glycerol was greater in MICE (P = 0.020) and CRE (P = 0.001) compared with CON. Furthermore, nonesterified fatty acid area under the curve had a moderate-to-strong effect in CRE versus MICE and HIIE (Cohen's d = -0.76 and -0.50, respectively).CONCLUSIONS: In persons with paraplegia, high-intensity exercise increased postprandial energy expenditure independent of the energy cost of exercise. Furthermore, exercise combining resistance and endurance modes (CRE) showed the greater effect on postprandial lipid oxidation.</p

    Mass Segregation in the Globular Cluster Palomar 5 and its Tidal Tails

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    We present the stellar main sequence luminosity function (LF) of the disrupted, low-mass, low-concentration globular cluster Palomar 5 and its well-defined tidal tails, which emanate from the cluster as a result of its tidal interaction with the Milky Way. The results of our deep (B ~ 24.5) wide-field photometry unequivocally indicate that preferentially fainter stars were removed from the cluster so that the LF of the cluster's main body exhibits a significant degree of flattening compared to other globular clusters. There is clear evidence of mass segregation, which is reflected in a radial variation of the LFs. The LF of the tidal tails is distinctly enhanced with faint, low-mass stars. Pal 5 exhibits a binary main sequence, and we estimate a photometric binary frequency of roughly 10%. Also the binaries show evidence of mass segregation with more massive binary systems being more strongly concentrated toward the cluster center.Comment: 14 pages, 12 figures, accepted for publication in the Astronomical Journa
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