4,878 research outputs found

    The Effects of Beetroot Juice on VO2max and Blood Pressure During Submaximal Exercise

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    Supplementation with beetroot juice (BR) has been shown to reduce blood pressure (BP) at rest and improve several performance parameters during submaximal and maximal exercise. BR effects on BP during submaximal exercise have not been investigated. Furthermore, the effects of BR on VO2max are inconclusive. The purpose of this study was to investigate the effects of BR on VO2max and BP during submaximal exercise. 20 healthy, recreationally trained volunteers (age 21.8±2.35 years, weight 75.10±10.62 kg, height 177.4±6.39 cm) participated in this study, which had a double-blind placebo controlled randomized crossover design. Participants began supplementation with either 8 oz. servings of placebo (water with McCormick red food coloring FD&C reds 40 and 3) or 70 ml BR servings (Beet it, James White Drinks, Ipswich, UK, nitrate concentration of 6.4 mmol/day) for 7 days. Participants completed a modified ramp treadmill protocol for determination of VO2max. BP was taken at 70% of max heart rate calculated using the Karvonen method. There was no significant change in VO2max after BR supplementation (51.07±6.12 ml/kg/min) compared to placebo (50.46±6.06 ml/kg/min), t(19)=1.41, p=0.17. There was also no significant change in systolic blood pressure after beetroot juice supplementation (180.65±23.37 mm Hg) compared to placebo (177.65±22.07 mm Hg), t(19)=0.49, p=0.63, nor in diastolic blood pressure after beetroot juice supplementation (92.90±18.89 mm Hg) compared to placebo (90.75±17.73 mm Hg), t(19)=0.51, p=0.62. BR did not affect VO2max, nor did it affect blood pressure during submaximal exercise

    Quantum phase transitions of atom-molecule Bose mixtures in a double-well potential

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    The ground state and spectral properties of Bose gases in double-well potentials are studied in two different scenarios: i) an interacting atomic Bose gas, and ii) a mixture of an atomic gas interacting with diatomic molecules. A ground state second-order quantum phase transition (QPT) is observed in both scenarios. For large attractive values of the atom-atom interaction, the ground-state is degenerate. For repulsive and small attractive interaction, the ground-state is not degenerate and is well approximated by a boson coherent state. Both systems depict an excited state quantum phase transition (ESQPT). For the mixed atom-molecule system the critical point of the ESQPT displays a discontinuity in the first derivative of the density of states.Comment: 25 pages, 18 figures. RevTex 4.1 (version to appear in Phys. Rev. E

    Music Learning Tools for Android Devices

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    In this paper, a musical learning application for mobile devices is presented. The main objective is to design and develop an application capable of offering exercises to practice and improve a selection of music skills, to users interested in music learning and training. The selected music skills are rhythm, melodic dictation and singing. The application includes an audio signal analysis system implemented making use of the Goertzel algorithm which is employed in singing exercises to check if the user sings the right musical note. This application also includes a graphical interface to represent musical symbols. A set of tests were conducted to check the usefulness of the application as musical learning tool. A group of users with different music knowledge have tested the system and reported to have found it effective, easy and accessible.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Scanning Tunneling Microscopy Studies of Diamond Films and Optoelectronic Materials

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    We present a summary of the research, citations of publications resulting from the research and abstracts of such publications. We have made no inventions in the performance of the work in this project. The main goals of the project were to set up a Chemical Vapor Deposition (CVD) diamond growth system attached to an UltraHigh Vacuum (UHV) atomic resolution Scanning Tunneling Microscopy (STM) system and carry out experiments aimed at studying the properties and growth of diamond films using atomic resolution UHV STM. We successfully achieved these goals. We observed, for the first time, the atomic structure of the surface of CVD grown epitaxial diamond (100) films using UHV STM. We studied the effects of atomic hydrogen on the CVD diamond growth process. We studied the electronic properties of the diamond (100) (2x1) surface, and the effect of alkali metal adsorbates such as Cs on the work function of this surface using UHV STM spectroscopy techniques. We also studied, using STM, new electronic materials such as carbon nanotubes and gold nanostructures. This work resulted in four publications in refereed scientific journals and five publications in refereed conference proceedings

    Scanning tunneling microscopy studies of diamond films and optoelectronic materials

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    In this report, we report on progress achieved from 12/1/92 to 10/1/93 under the grant entitled 'Scanning Tunneling Microscopy Studies of Diamond Films and Optoelectronic Materials'. We have set-up a chemical vapor deposition (CVD) diamond film growth system and a Raman spectroscopy system to study the nucleation and growth of diamond films with atomic resolution using scanning tunneling microscopy (STM). A unique feature of the diamond film growth system is that diamond films can be transferred directly to the ultrahigh vacuum (UHV) chamber of a scanning tunneling microscope without contaminating the films by exposure to air. The University of North Texas (UNT) provided 20,000thisyearasmatchingfundsfortheNASAgranttopurchasethediamondgrowthsystem.Inaddition,UNTprovidedaCoherentInnova90SArgonionlaser,aSpex1404doublespectrometer,andaNewportopticaltablecosting20,000 this year as matching funds for the NASA grant to purchase the diamond growth system. In addition, UNT provided a Coherent Innova 90S Argon ion laser, a Spex 1404 double spectrometer, and a Newport optical table costing 90,000 to set-up the Raman spectroscopy system. The CVD diamond growth system and Raman spectroscopy system will be used to grow and characterize diamond films with atomic resolution using STM as described in our proposal. One full-time graduate student and one full-time undergraduate student are supported under this grant. In addition, several graduate and undergraduate students were supported during the summer to assist in setting-up the diamond growth and Raman spectroscopy systems. We have obtained research results concerning STM of the structural and electronic properties of CVD grown diamond films, and STM and scanning tunneling spectroscopy of carbon nanotubes. In collaboration with the transmission electron microscopy (TEM) group at UNT, we have also obtained results concerning the optoelectronic material siloxene. These results were published in refereed scientific journals, submitted for publication, and presented as invited and contributed talks at scientific conferences

    OPTIMAL RAILWAY INFRASTRUCTURE MAINTENANCE AND REPAIR POLICIES TO MANAGE RISK UNDER UNCERTAINTY WITH ADAPTIVE CONTROL

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    The aim of this paper is to apply two adaptive control formulations under uncertainty, say open-loop and closed-loop, to the process of developing maintenance and repair policies for railway infrastructures. To establish the optimal maintenance and repair policies for railway lines, we use a previous design of risk model based on two factors: the criticality and the deterioration ratios of the facilities. Thus, our theory benefits from the Reliability Centered Management methodology application, but it also explicitly models uncertainty in characterizing a facility deterioration rate to decide the optimal policy to maintain the railway infrastructures. This may be the major contribution of this work. To verify the models presented, a computation study has been developed and tested for a real scenario: the railway line Villalba-Cercedilla in Madrid (Spain). Our results demonstrate again that applying any adaptive formulation, the cost of the railway lines maintenance shown is decreased. Moreover applying a Closed Loop Formulation the cost associated to the risk takes smaller values (40% less cost for the same risk than the deterministic approach), but with an Open Loop formulation the generated risk in the railway line is also smaller.
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