21,474 research outputs found
Maxwell meets Korn: A New Coercive Inequality for Tensor Fields with Square-Integrable Exterior Derivative
Maxwell meets Korn: A New Coercive Inequality for Tensor Fields with
Square-Integrable Exterior DerivativeComment: Key Words: Korn's inequality, theory of generalized Maxwell
equations, Helmholtz decomposition, Poincare/Friedrichs-type estimates,
incompatible tensor
These Perilous Times
"These Perilous Times" presents metaphysical perspectives regarding humanity's current experiences
Clusters and halos in light nuclei
The fermionic molecular dynamics approach uses Gaussian wave packets as
single-particle basis states. Many-body basis states are Slater determinants
projected on parity, angular momentum and total linear momentum. The
wave-packet basis is very flexible - FMD contains harmonic oscillator shell
model and Brink-type cluster states as special cases. The parameters of the
wave packets are obtained by variation. A realistic effective interaction
derived from the Argonne V18 interaction by means of the unitary correlation
operator method is employed. We discuss the fully microscopic calculation of
the 3He(alpha,gamma)7Be capture reaction within the FMD approach. The model
space contains frozen cluster configurations at large distances and polarized
configurations in the interaction region. The polarized configurations are
essential for a successful description of the 7Be bound state properties and
for the S- and D-wave scattering states. The calculated cross section agrees
well with recent measurements regarding both the absolute normalization and the
energy dependence. We also discuss the structure of the cluster states,
including the famous Hoyle state, in 12C. From the two-body densities we
conclude that the Hoyle state has a spatially extended triangular alpha-cluster
structure, whereas the third 0+ state features a chain-like obtuse triangle
structure. We also calculate the N hbar Omega decomposition of our wave
functions to illuminate the challenges of no-core shell model calculations for
these cluster states.Comment: 7 pages, Proceedings of Horizons of Innovative Theories, Experiments,
and Supercomputing in Nuclear Physics (HITES 2012
Efficient computation of low-lying eigenmodes of non-Hermitian Wilson-Dirac type matrices
A polynomial transformation for non-Hermitian matrices is presented, which
provides access to wedge-shaped spectral windows. For Wilson-Dirac type
matrices this procedure not only allows the determination of the physically
interesting low-lying eigenmodes but also provides a substantial acceleration
of the eigenmode algorithm employed.Comment: Lattice2001(algorithms
The NGO Sector in Community Development: Emerging roles, strategies and identities
This community engaged thesis will articulate some of the identities, patterns, and dominant practices of NGOs related to community development in the hope of uncovering emerging trends. The literature review of this thesis will have a slight focus on NGOâs working in direct conjunction with the HIV/AIDS epidemic in sub-Saharan Africa. In addition, it will manifest the promise of social capital as necessary to an organizationâs success. Civic participation remains critical in enabling an NGO to be politically active, to continue building networks, and instilling positive social attitudes. After expounding on these issues, this thesis will then propose a solution- more specifically, a model- that attempts to relate field research findings to current grassroot initiatives that have succeeded in achieving community development through youth empowerment and education in Rhode Island. The strategy of youth empowerment and civic engagement is an effective model for community development and positive social change. By sharing insights and identifying best practices, the NGO sector can enhance coordination and partnerships for effective country-level implementation of youth development initiatives. The author hopes that the findings of this thesis and her field research will be employed and utilized in the development of progressive community-based organizations dedicated to combating the HIV/AIDS virus in Africa
Microscopic calculation of the 3He(alpha,gamma)7Be and 3H(alpha,gamma)7Li capture cross sections using realistic interactions
The radiative capture cross sections for the 3He(alpha,gamma)7Be and
3H(alpha,gamma)7Li reactions are calculated in the fully microscopic fermionic
molecular dynamics approach using a realistic effective interaction that
reproduces the nucleon-nucleon scattering data. At large distances bound and
scattering states are described by antisymmetrized products of 4He and 3He/3H
ground states. At short distances the many-body Hilbert space is extended with
additional many-body wave functions needed to represent polarized clusters and
shell-model-like configurations. Properties of the bound states are described
well, as are the scattering phase shifts. The calculated S factor for the
3He(alpha,gamma)7Be reaction agrees very well with recent experimental data
both in absolute normalization and energy dependence. In case of the
3H(alpha,gamma)7Li reaction the calculated S factor is larger than available
experimental data by about 15%.Comment: 4 pages, 5 figures, published versio
The HIV/AIDS Pandemic in African American MSM: Targets for Intervention
The Centers for Disease Control and Prevention estimated in 2005 that 46% of African American men who have sex with men (MSM) are HIV positive. This review explores the unique factors that contribute to risky sexual behavior and the spread of HIV within this population, suggesting that the disparate prevalence of HIV among African American MSM is rooted in experiences of stigmatization from multiple sources and lack of social support from society at large as well as from within the African American community. Beliefs in HIV conspiracy myths are also thought to hinder HIV education, awareness and prevention for African American MSM. Past interventions to reduce the spread of HIV among African American MSM are reviewed, and suggestions for future individual and community level interventions to reduce stigma, enhance social support, and de-emphasize beliefs in HIV myths are presented
- âŠ