358 research outputs found

    Complexiton Solutions of the Toda Lattice Equation

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    A set of coupled conditions consisting of differential-difference equations is presented for Casorati determinants to solve the Toda lattice equation. One class of the resulting conditions leads to an approach for constructing complexiton solutions to the Toda lattice equation through the Casoratian formulation. An analysis is made for solving the resulting system of differential-difference equations, thereby providing the general solution yielding eigenfunctions required for forming complexitons. Moreover, a feasible way is presented to compute the required eigenfunctions, along with examples of real complexitons of lower order.Comment: 21 pages, Latex, to appear in Physica

    Group studio cycling; an effective intervention to improve cardio-metabolic health in overweight physically inactive individuals

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    Introduction: Supervised, laboratory based studies of high intensity interval training (HIIT) is effective at improving health markers in groups at risk of cardiovascular and metabolic disease. Studio cycling, incorporating aerobic and high intensity exercise, may offer a platform for the implementation of HIIT within the wider community. Methods: Eight, overweight, physically inactive (<1.5 hr·wk-1) but otherwise healthy volunteers completed eight weeks of supervised studio cycling lasting 20-50 minutes 3 times per week. Participants underwent assessment for maximal oxygen uptake (VO2max) body composition, blood lipids, glucose tolerance and insulin resistance before and after the intervention. Results: Adherence to training was >95%. Mean and peak intensity were equivalent to 83% and 97% of HRmax·VO2max increased from 27.1 ± 4.7 mL·kg·min-1 to 30.3 ± 4.3 mL·kg·min-1 (p < 0.0001). Body fat percentage was reduced by 13.6% from 31.8 ± 2.4% to 27.5 ± 4.5% (p < 0.05). Total cholesterol (4.8 ± 1.1 mmol·L-1 to 4.2 ± 1.2 mmol·L-1) and low-density lipoprotein cholesterol (2.6 ± 0.9 mmol·L-1 to 2.0 ± 1.2 mmol·L-1) were reduced (both p < 0.05). There were no significant differences to glucose tolerance or insulin resistance. Discussion: Group exercise is effective at improving the cardio-metabolic health in previously physically inactive overweight individuals. Coupled with the high adherence rate, studio cycling offers an effective intervention improving cardiovascular health in physically inactive cohorts. Conclusions: Studio cycling can be implemented as a highly effective high intensity interval training intervention for improving health in overweight, inactive individuals and may promote improved exercise adherence

    Assessment and parameter identification of simplified models to describe the kinetics of semi continuous biomethane production from anaerobic digestion of green and food waste

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    Biochemical reactions occurring during anaerobic digestion have been modelled using reaction kinetic equations such as first-order, Contois and Monod which are then combined to form mechanistic models. This work considers models which include between one and three biochemical reactions to investigate if the choice of the reaction rate equation, complexity of the model structure as well as the inclusion of inhibition plays a key role in the ability of the model to describe the methane production from the semi-continuous anaerobic digestion of green waste (GW) and food waste (FW). A parameter estimation method was used to investigate the most important phenomena influencing the biogas production process. Experimental data were used to numerically estimate the model parameters and the quality of fit was quantified. Results obtained reveal that the model structure (i.e. number of reactions, inhibition) has a much stronger influence on the quality of fit compared with the choice of kinetic rate equations. In the case of GW there was only a marginal improvement when moving from a one to two reaction model, and none with inclusion of inhibition or three reactions. However, the behaviour of FW digestion was more complex and required either a two or three reaction model with inhibition functions for both ammonia and volatile fatty acids. Parameter values for the best fitting models are given for use by other authors

    Lower volume throughout the taper and higher intensity in the last interval session prior to a 1,500 m time trial improves performance

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    Eight highly-trained middle-distance runners (1,500 m personal best 4:01.4 ± 0:09.2 min) completed two 7-day tapers, separated by at least 3 weeks of regular training: (i) prescribed using prediction models from elite middle-distance runners, where continuous running volume was reduced by 30% and interval intensity was equal to 1,500 m race pace (RP); and (ii) continuous running volume was reduced by 60% and intensity of the final interval session was completed at 110% of 1,500 m race pace (HI). Performance was assessed using 1,500 m time trials on an indoor 200 m track one day before, and one day after each taper. Performance time was improved after HI by 5.2 ± 3.7 s (mean ± 90% confidence limits, p = 0.03) and by 3.2 ± 3.8 s after RP (p = 0.15). The first and second 300-m segments of the 1,500 m time trial were faster post-taper in RP (p = 0.012 and p = 0.017, respectively) and HI (both p = 0.012). Running faster than race pace late in a low-volume taper is recommended to improve 1,500 m track performance. A positive pacing strategy is adopted after tapering, although care should be taken to avoid an over-fast start. Novel Findings: A large reduction in volume during tapering and an increase in final interval session intensity improves running performance. Athletes adopt a negative pacing strategy before tapering and a positive-pacing strategy after tapering

    Darboux Transformations for a Lax Integrable System in 2n2n-Dimensions

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    A 2n2n-dimensional Lax integrable system is proposed by a set of specific spectral problems. It contains Takasaki equations, the self-dual Yang-Mills equations and its integrable hierarchy as examples. An explicit formulation of Darboux transformations is established for this Lax integrable system. The Vandermonde and generalized Cauchy determinant formulas lead to a description for deriving explicit solutions and thus some rational and analytic solutions are obtained.Comment: Latex, 14 pages, to be published in Lett. Math. Phy

    The effects of an increase in intensity during tapering on 1,500m running performance

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    We examined the effect of completing the final interval training session during a taper at either: i) race pace; or ii) faster than race pace, on 1,500 m running performance and neuromuscular performance. Ten trained runners (age 21.7 ± 3.0 years, height 182.9 ± 7.0 cm, body mass 73.4 ± 6.8 kg, personal best 1,500 m time 4:17.5 ± 0:26.9 min) completed two conditions, consisting of 7-d of regular training and a 7-d taper, separated by three weeks of training. In one condition, the taper was prescribed using prediction models based on the practices of elite British middle-distance runners, with the intensity of the final interval session being equal to 1,500 m race pace (RP). The taper was repeated in the HI condition, except the final interval session was completed at 115% of 1,500 m race pace. A 1,500 m treadmill time trial, measures of maximum voluntary isometric strength (MVC) and rate of force development (RFD) were completed before and after regular training and tapering. Performance was most likely improved after RP (mean ± 90% confidence limits, 10.1 ± 1.6 s), and possibly beneficial after HI (4.2 ± 12.0 s). Both MVC force (p = 0.002) and RFD (p = 0.02) were improved after tapering, without differences between conditions. A race-pace taper based on the practices of elite middle-distance runners is recommended to improve performance in young, sub-elite runners. The effect of this strategy with an increase in interval intensity is highly variable and should be implemented with caution

    OxyCAP UK: Oxyfuel Combustion - academic Programme for the UK

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    The OxyCAP-UK (Oxyfuel Combustion - Academic Programme for the UK) programme was a ÂŁ2 M collaboration involving researchers from seven UK universities, supported by E.On and the Engineering and Physical Sciences Research Council. The programme, which ran from November 2009 to July 2014, has successfully completed a broad range of activities related to development of oxyfuel power plants. This paper provides an overview of key findings arising from the programme. It covers development of UK research pilot test facilities for oxyfuel applications; 2-D and 3-D flame imaging systems for monitoring, analysis and diagnostics; fuel characterisation of biomass and coal for oxyfuel combustion applications; ash transformation/deposition in oxyfuel combustion systems; materials and corrosion in oxyfuel combustion systems; and development of advanced simulation based on CFD modelling

    The Main Belt Comets and ice in the Solar System

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    We review the evidence for buried ice in the asteroid belt; specifically the questions around the so-called Main Belt Comets (MBCs). We summarise the evidence for water throughout the Solar System, and describe the various methods for detecting it, including remote sensing from ultraviolet to radio wavelengths. We review progress in the first decade of study of MBCs, including observations, modelling of ice survival, and discussion on their origins. We then look at which methods will likely be most effective for further progress, including the key challenge of direct detection of (escaping) water in these bodies
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