1,332 research outputs found
How Music Shapes Our Identities and why it Matters: Case studies of professional musicians
Brain research has demonstrated that music uniquely contributes to neural functioning, but little is known about how losing the ability to produce music, which may be inherent to personal identity for professional singers, impacts quality of life. This study explored identity and music in the lives of five well-known vocal music professionals selected because they have publicly talked about the role of music in their lives via books, televised interviews, and documentaries. The careers of three of the individuals were disrupted by neurogenic disease; one lost the ability to sing after treatment for vocal nodules; and the fifth individual remains unaffected as she continues to perform. There was no actual contact as only publicly available source material (audio and video interviews, news articles, books, and social media) were used. The procedure of the study selected a balanced corpus of material that provided insight about careers before, during, and after medical disruption. Line-by-line transcripts of video and audio material were completed and added to any text materials. Narrative analysis was used to identify themes related to the self-identity of each of the professional singers at three points in their career: early, established, and post diagnosis. Major and minor themes were abstracted from the transcriptions. Cross coding for inter-rater agreement completed on 10% of the total corpus reached 94%
Low-Latitude Coronal Holes at the Minimum of the 23rd Solar Cycle
Low and mid-latitude coronal holes (CHs) observed on the Sun during the
current solar activity minimum (from September 21, 2006, Carrington rotation
(CR) 2048, until June 26, 2009 (CR 2084)) were analyzed using {\it SOHO}/EIT
and STEREO-A SECCHI EUVI data. From both the observations and Potential Field
Source Surface (PFSS) modeling, we find that the area occupied by CHs inside a
belt of around the solar equator is larger in the current 2007
solar minimum relative to the similar phase of the previous 1996 solar minimum.
The enhanced CH area is related to a recurrent appearance of five persistent
CHs, which survived during 7-27 solar rotations. Three of the CHs are of
positive magnetic polarity and two are negative. The most long-lived CH was
being formed during 2 days and existed for 27 rotations. This CH was associated
with fast solar wind at 1 AU of approximately 620 km s. The 3D
MHD modeling for this time period shows an open field structure above this CH.
We conclude that the global magnetic field of the Sun possessed a multi-pole
structure during this time period. Calculation of the harmonic power spectrum
of the solar magnetic field demonstrates a greater prevalence of multi-pole
components over the dipole component in the 2007 solar minimum compared to the
1996 solar minimum. The unusual large separation between the dipole and
multi-pole components is due to the very low magnitude of the dipole component,
which is three times lower than that in the previous 1996 solar minimum.Comment: 14 pages, 7 figure
Coupling of Coronal and Heliospheric Magnetohydrodynamic Models: Solution Comparisons and Verification
Two well-established magnetohydrodynamic (MHD) codes are coupled to model the solar corona and the inner heliosphere. The corona is simulated using the MHD algorithm outside a sphere (MAS) model. The LyonâFedderâMobarry (LFM) model is used in the heliosphere. The interface between the models is placed in a spherical shell above the critical point and allows both models to work in either a rotating or an inertial frame. Numerical tests are presented examining the coupled model solutions from 20 to 50 solar radii. The heliospheric simulations are run with both LFM and the MAS extension into the heliosphere, and use the same polytropic coronal MAS solutions as the inner boundary condition. The coronal simulations are performed for idealized magnetic configurations, with an out-of-equilibrium flux rope inserted into an axisymmetric background, with and without including the solar rotation. The temporal evolution at the inner boundary of the LFM and MAS solutions is shown to be nearly identical, as are the steady-state background solutions, prior to the insertion of the flux rope. However, after the coronal mass ejection has propagated through the significant portion of the simulation domain, the heliospheric solutions diverge. Additional simulations with different resolution are then performed and show that the MAS heliospheric solutions approach those of LFM when run with progressively higher resolution. Following these detailed tests, a more realistic simulation driven by the thermodynamic coronal MAS is presented, which includes solar rotation and an azimuthally asymmetric background and extends to the Earthâs orbit
A Hot Helium Plasma in the Galactic Center Region
Recent X-ray observations by the space mission Chandra confirmed the
astonishing evidence for a diffuse, hot, thermal plasma at a temperature of 9.
K (8 keV) found by previous surveys to extend over a few hundred parsecs
in the Galactic Centre region. This plasma coexists with the usual components
of the interstellar medium such as cold molecular clouds and a soft (~0.8 keV)
component produced by supernova remnants, and its origin remains uncertain.
First, simple calculations using a mean sound speed for a hydrogen-dominated
plasma have suggested that it should not be gravitationally bound, and thus
requires a huge energy source to heat it in less than the escape time. Second,
an astrophysical mechanism must be found to generate such a high temperature.
No known source has been identified to fulfill both requirements. Here we
address the energetics problem and show that the hot component could actually
be a gravitationally confined helium plasma. We illustrate the new prospects
this opens by discussing the origin of this gas, and by suggesting possible
heating mechanisms.Comment: 9 pages, accepted for publication in APJ
Projections of Atmospheric Nitrogen Deposition to the Chesapeake Bay Watershed
Atmospheric deposition is among the largest pathways of nitrogen loading to the Chesapeake Bay Watershed (CBW). The interplay between future climate and emission changes in and around the CBW will likely shift the future nutrient deposition abundance and chemical regime (e.g., oxidized vs. reduced nitrogen). In this work, a Representative Concentration Pathway from the Community Earth System Model is dynamically downscaled using a recently updated Weather Research and Forecasting model that subsequently drives the Community Multiscale Air Quality model coupled to the agroeconomic Environmental Policy Integrated Climate model. The relative impacts of emission and climate changes on atmospheric nutrient deposition are explored for a recent historical period and a period centered on 2050. The projected regional emissions in Community Multiscale Air Quality reflect current federal and state regulations, which use baseline and projected emission years 2011 and 2040, respectively. The historical simulations of 2-m temperature (T2) and precipitation (PRECIP) have cool and dry biases, and temperature and PRECIP are projected to both increase. Ammonium wet deposition agrees well with observations, but nitrate wet deposition is underpredicted. Climate and deposition changes increase simulated future ammonium fertilizer application. In the CBW by 2050, these changes (along with widespread decreases in anthropogenic nitrogen oxide and sulfur oxide emissions, and relatively constant ammonia emissions) decrease total nitrogen deposition by 21%, decrease annual average oxidized nitrogen deposition by 44%, and increase reduced nitrogen deposition by 10%. These results emphasize the importance of decreased anthropogenic emissions on the control of future nitrogen loading to the Chesapeake Bay in a changing climate
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Metrics for solar wind prediction models: Comparison of empirical, hybrid, and physics-based schemes with 8 years of L1 observations
Space weather effects on technological systems originate with energy carried from the Sun to the terrestrial environment by the solar wind. In this study, we present results of modeling of solar corona-heliosphere processes to predict solar wind conditions at the L1 Lagrangian point upstream of Earth. In particular we calculate performance metrics for (1) empirical, (2) hybrid empirical/physics-based, and (3) full physics-based coupled corona-heliosphere models over an 8-year period (1995â2002). L1 measurements of the radial solar wind speed are the primary basis for validation of the coronal and heliosphere models studied, though other solar wind parameters are also considered. The models are from the Center for Integrated Space-Weather Modeling (CISM) which has developed a coupled model of the whole Sun-to-Earth system, from the solar photosphere to the terrestrial thermosphere. Simple point-by-point analysis techniques, such as mean-square-error and correlation coefficients, indicate that the empirical coronal-heliosphere model currently gives the best forecast of solar wind speed at 1 AU. A more detailed analysis shows that errors in the physics-based models are predominately the result of small timing offsets to solar wind structures and that the large-scale features of the solar wind are actually well modeled. We suggest that additional âtuningâ of the coupling between the coronal and heliosphere models could lead to a significant improvement of their accuracy. Furthermore, we note that the physics-based models accurately capture dynamic effects at solar wind stream interaction regions, such as magnetic field compression, flow deflection, and density buildup, which the empirical scheme cannot
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