1,688 research outputs found
Optically pumped resonance magnetometer for determining vectoral components in a spatial coordinate system Patent
Design and development of optically pumped resonance magnetometer for determining vectoral components in spatial coordinate syste
Route to hyperchaos in Rayleigh-Benard convection
Transition to hyperchaotic regimes in Rayleigh-Benard convection in a square
periodicity cell is studied by three-dimensional numerical simulations. By
fixing the Prandtl number at P=0.3 and varying the Rayleigh number as a control
parameter, a bifurcation diagram is constructed where a route to hyperchaos
involving quasiperiodic regimes with two and three incommensurate frequencies,
multistability, chaotic intermittent attractors and a sequence of boundary and
interior crises is shown. The three largest Lyapunov exponents exhibit a linear
scaling with the Rayleigh number and are positive in the final hyperchaotic
attractor. Thus, a route to weak turbulence is found
Transport of toroidal magnetic field by the meridional flow at the base of the solar convection zone
In this paper we discuss the transport of toroidal magnetic field by a weak
meridional flow at the base of the convection zone. We utilize the differential
rotation and meridional flow model developed by Rempel and incorporate feedback
of a purely toroidal magnetic field in two ways: directly through the Lorentz
force (magnetic tension) and indirectly through quenching of the turbulent
viscosity, which affects the parametrized turbulent angular momentum transport
in the model. In the case of direct Lorentz force feedback we find that a
meridional flow with an amplitude of around 2 m/s can transport a magnetic
field with a strength of 20 to 30 kG. Quenching of turbulent viscosity leads to
deflection of the meridional flow from the magnetized region and a significant
reduction of the transport velocity if the magnetic field is above
equipartition strength.Comment: 8 pages, 6 figure
Penumbral structure and outflows in simulated sunspots
Sunspots are concentrations of magnetic field on the visible solar surface
that strongly affect the convective energy transport in their interior and
surroundings. The filamentary outer regions (penumbrae) of sunspots show
systematic radial outward flows along channels of nearly horizontal magnetic
field. These flows were discovered 100 years ago and are present in all fully
developed sunspots. Using a comprehensive numerical simulation of a sunspot
pair, we show that penumbral structures with such outflows form when the
average magnetic field inclination to the vertical exceeds about 45 degrees.
The systematic outflows are a component of the convective flows that provide
the upward energy transport and result from anisotropy introduced by the
presence of the inclined magnetic field.Comment: 19 pages, 8 figures, main Science article + supporting online
material combined into one fil
Edge of Chaos and Genesis of Turbulence
The edge of chaos is analyzed in a spatially extended system, modeled by the
regularized long-wave equation, prior to the transition to permanent
spatiotemporal chaos. In the presence of coexisting attractors, a chaotic
saddle is born at the basin boundary due to a smooth-fractal metamorphosis. As
a control parameter is varied, the chaotic transient evolves to well-developed
transient turbulence via a cascade of fractal-fractal metamorphoses. The edge
state responsible for the edge of chaos and the genesis of turbulence is an
unstable travelling wave in the laboratory frame, corresponding to a saddle
point lying at the basin boundary in the Fourier space
Gerotranscendence and Successful Aging: The Lived Experience
With the impending explosion in the number of older adults in this country, new ways of understanding and serving this population are vital to success in clinical social work practice. This study explored the lived aging experience from the perspective of older adults in the context of gerotranscendence and successful aging. Nine older adults over the age of 80 were interviewed by the researcher. The findings of the study indicate the presence of gerotranscendence, and confirmed that it coincided with the concept of successful aging in all nine participants. Implications include the need for a more holistic understanding of older adults, policy development to support older adults in the community, agency policies that acknowledge and foster the development of gerotranscendence, further research on gerotranscendence and the economics of aging, assessments of providers currently using the principles of gerotranscendence in practice, needs assessments for future program development, and the development of educated and skilled professionals to address the diverse needs of older adults
Predicting Career Success In Classically Trained Musicians
The present study examined several factors (performance anxiety, anxiety sensitivity, vocational decidedness, and amount of time in the profession) that are believed to contribute to success in music performance professions. Existing literature highlights the unique role that some of these variables play in career success, however no research has examined the combined impact of these four factors or has attempted to identify the relative weight each predictor holds.
The present study recruited participants through various professional music organizations that require a minimum and standardized level of music training. Participants were invited to complete an on-line survey that consisted of measures of music performance anxiety (Kenny Music Performance Anxiety Inventory), anxiety sensitivity (Anxiety Sensitivity Index-Revised), vocational indecision (5-item likert-like scale developed for this study), amount of time in the profession, and additional demographic questions. A total of 256 usable questionnaires were collected for the data analysis and reflected a largely Caucasian sample (89.5%) ranging in age from 19 to 82.
The study findings showed vocational indecision to have the highest predictive ability (i.e. higher vocational indecision predicted lower level of career success) followed by amount of time in the profession (longer amount of time in the profession predicted lower level of career success), music performance anxiety and anxiety sensitivity (higher levels of both predicting lower levels of career success)
Properties of Umbral Dots as Measured from the New Solar Telescope Data and MHD Simulations
We studied bright umbral dots (UDs) detected in a moderate size sunspot and
compared their statistical properties to recent MHD models. The study is based
on high resolution data recorded by the New Solar Telescope at the Big Bear
Solar Observatory and 3D MHD simulations of sunspots. Observed UDs, living
longer than 150 s, were detected and tracked in a 46 min long data set, using
an automatic detection code. Total 1553 (620) UDs were detected in the
photospheric (low chromospheric) data. Our main findings are: i) none of the
analyzed UDs is precisely circular, ii) the diameter-intensity relationship
only holds in bright umbral areas, and iii) UD velocities are inversely related
to their lifetime. While nearly all photospheric UDs can be identified in the
low chromospheric images, some small closely spaced UDs appear in the low
chromosphere as a single cluster. Slow moving and long living UDs seem to exist
in both the low chromosphere and photosphere, while fast moving and short
living UDs are mainly detected in the photospheric images. Comparison to the 3D
MHD simulations showed that both types of UDs display, on average, very similar
statistical characteristics. However, i) the average number of observed UDs per
unit area is smaller than that of the model UDs, and ii) on average, the
diameter of model UDs is slightly larger than that of observed ones.Comment: Accepted by the AP
Gerotranscendence and Successful Aging: The Lived Experience
With the impending explosion in the number of older adults in this country, new ways of understanding and serving this population are vital to success in clinical social work practice. This study explored the lived aging experience from the perspective of older adults in the context of gerotranscendence and successful aging. Nine older adults over the age of 80 were interviewed by the researcher. The findings of the study indicate the presence of gerotranscendence, and confirmed that it coincided with the concept of successful aging in all nine participants. Implications include the need for a more holistic understanding of older adults, policy development to support older adults in the community, agency policies that acknowledge and foster the development of gerotranscendence, further research on gerotranscendence and the economics of aging, assessments of providers currently using the principles of gerotranscendence in practice, needs assessments for future program development, and the development of educated and skilled professionals to address the diverse needs of older adults
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