10,077 research outputs found
Adaptations in cardiac structure and function following high intensity interval training in a physically inactive population
Purpose:
Physical inactivity is associated with increased risk of cardiovascular disease and myocardial dysfunction. High intensity interval training (HIIT) has been shown to improve cardiovascular health; however, adaptations of cardiac structure and function are uncertain. Therefore, the aim of the present study was to analyse cardiac structural and functional adaptations to a HIIT protocol.
Methods:
Forty-one physically inactive individuals (males n=20 and females n=21) were randomised into either a 4-week HIIT intervention or control group. The HIIT consisted of 3 x 30-second maximal cycle ergometer sprints against a resistance of 7.5% body weight, separated by 2-minute active recovery periods. In total, 12-sessions were performed. All cardiac structural and functional parameters were measured by quantitative 2D transthoracic echocardiography, performed using a commercially available, portable ultrasound system (Vividâq, GE Healthcare, Milwaukee, Wisconsin) with a 1.5â3.6 MHz phased array transducer (M4SâRS Matrix cardiac ultrasound probe).
Results:
The HIIT intervention produced significant improvements in resting heart rate (65.59 ± 10.15 to 63.05 ± 13.42 b·min-1, P=0.013), stroke volume (55.48 ± 16.27 to 64.24 ± 20.62ml, P=0.015), left ventricular end diastolic volume (115.59 ± 28.34 to 131.94 ± 33.40ml, P=0.025), E/a ratio (1.98 ± 0.48 to 1.95 ± 0.55; P=0.027), average E/eâ ratio (5.41 ± 1.17 to 5.22 ± 0.89; P=0.002) and isovolumetric relaxation time (81.23 ± 12.85 to 77.83 ± 9.81 m·s-1; P=0.022) compared to the control group.
Conclusion:
HIIT produced significant improvements in resting haemodynamics and diastolic function. This time efficient exercise intervention produces important improvements in myocardial function in a physically inactive population, which may be of clinical importance in higher risk populations
Crustal fault reactivation facilitating lithospheric folding/buckling in the central Indian Ocean
High-quality, normal-incidence seismic reflection data confirm that tectonic deformation in the central Indian Ocean occurs at two spatial scales: whole lithosphere folding with wavelengths varying between 100 and 300 km, and compressional reactivation of crustal faults with a characteristic spacing of c. 5 km. Faults penetrate through the crust and probably into the upper mantle. Both types of deformation are driven by regional large intraplate stresses originating from the Indo-Eurasian collision. Numerical modelling of the spatial and temporal relationships between these two modes of deformations shows that, in agreement with geophysical observations, crustal faults are reactivated first with stick-slip behaviour. Subsequent lithospheric folding does not start until horizontal loading has significantly reduced the mechanical strength of the lithosphere, as predicted by elasto-plastic buckling theory. Modelling suggests that lithospheric folding does not develop in the absence of fault reactivation. Crustal fault reactivation, therefore, appears to be a key facilitating mechanism for oceanic lithospheric buckling in the central Indian Ocean
Current status of MCNP6 as a simulation tool useful for space and accelerator applications
For the past several years, a major effort has been undertaken at Los Alamos
National Laboratory (LANL) to develop the transport code MCNP6, the latest LANL
Monte-Carlo transport code representing a merger and improvement of MCNP5 and
MCNPX. We emphasize a description of the latest developments of MCNP6 at higher
energies to improve its reliability in calculating rare-isotope production,
high-energy cumulative particle production, and a gamut of reactions important
for space-radiation shielding, cosmic-ray propagation, and accelerator
applications. We present several examples of validation and verification of
MCNP6 compared to a wide variety of intermediate- and high-energy experimental
data on reactions induced by photons, mesons, nucleons, and nuclei at energies
from tens of MeV to about 1 TeV/nucleon, and compare to results from other
modern simulation tools.Comment: 4 pages, 3 figures, Proc. 11th Conference on the Intersections of
Particle and Nuclear Physics (CIPANP 2012), St. Petersburg, FL, May 28 - June
3, 201
Systems autonomy technology: Executive summary and program plan
The National Space Strategy approved by the President and Congress in 1984 sets for NASA a major goal of conducting effective and productive space applications and technology programs which contribute materially toward United States leadership and security. To contribute to this goal, OAST supports the Nation's civil and defense space programs and overall economic growth. OAST objectives are to ensure timely provision of new concepts and advanced technologies, to support both the development of NASA missions in space and the space activities of industry and other organizations, to utilize the strengths of universities in conducting the NASA space research and technology program, and to maintain the NASA centers in positions of strength in critical space technology areas. In line with these objectives, NASA has established a new program in space automation and robotics that will result in the development and transfer and automation technology to increase the capabilities, productivity, and safety of NASA space programs including the Space Station, automated space platforms, lunar bases, Mars missions, and other deep space ventures. The NASA/OAST Automation and Robotics program is divided into two parts. Ames Research Center has the lead role in developing and demonstrating System Autonomy capabilities for space systems that need to make their own decisions and do their own planning. The Jet Propulsion Laboratory has the lead role for Telerobotics (that portion of the program that has a strong human operator component in the control loop and some remote handling requirement in space). This program is intended to be a working document for NASA Headquarters, Program Offices, and implementing Project Management
Reciprocal Recommender System for Learners in Massive Open Online Courses (MOOCs)
Massive open online courses (MOOC) describe platforms where users with
completely different backgrounds subscribe to various courses on offer. MOOC
forums and discussion boards offer learners a medium to communicate with each
other and maximize their learning outcomes. However, oftentimes learners are
hesitant to approach each other for different reasons (being shy, don't know
the right match, etc.). In this paper, we propose a reciprocal recommender
system which matches learners who are mutually interested in, and likely to
communicate with each other based on their profile attributes like age,
location, gender, qualification, interests, etc. We test our algorithm on data
sampled using the publicly available MITx-Harvardx dataset and demonstrate that
both attribute importance and reciprocity play an important role in forming the
final recommendation list of learners. Our approach provides promising results
for such a system to be implemented within an actual MOOC.Comment: 10 pages, accepted as full paper @ ICWL 201
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