411 research outputs found
Quarkyonic Matter and Chiral Spirals
The nuclear matter, deconfined quark matter, and Quarkyonic matter in low
temperature region are classified based on the 1/Nc expansion. The chiral
symmetry in the Quarkyonic matter is investigated by taking into account
condensations of chiral particle-hole pairs. It is argued that the chiral
symmetry and parity are locally violated by the formation of chiral spirals, <
psibar exp(2 i mu z gamma^0 gamma^z) psi >. An extension to multiple chiral
spirals is also briefly discussed.Comment: Prepared for Hot Quark 2010, 4 page
Growth of high-quality GaAs/AlAs Bragg mirrors on patterned InP-based quantum well mesa structures
We have investigated the regrowth of GaAs/AlAs quarter-wave Bragg reflectors on patterned mesa InP-based quantum well heterostructures that can be fabricated into 1.55 μm vertical cavity surface emitting lasers. It is seen from transmission electron and scanning electron microscopy that the multiple layer GaAs-based mirrors can be grown on InP-based heterostructure mesas of diameters 10–40 μm without noticeable propagation of defects into the reflector layers or the quantum well region below. At the same time the photoluminescence from the quantum wells after regrowth indicates that lasers can be fabricated. © 1997 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70502/2/APPLAB-71-5-581-1.pd
From path dependence to policy mixes for Nordic electric mobility: lessons for accelerating future transport transitions?
We examine the problem of how to accelerate policies related to electric vehicles (EVs) in the Nordic countries Denmark, Finland, Norway and Sweden. These four Nordic countries represent an interesting collection of cases by virtue of having common decarbonization targets extending to the transport sector, interlinked electric energy systems and a joint electricity market largely based on low-carbon energy while they are open societies bent on innovation, making them well adaptable to a transition toward electric mobility. Our analytical framework drawing from transition research, lock-in and path dependency and institutionalism enables us to discern technological, institutional and behavioral mechanisms which can have both constraining and enabling effects vis-à-vis this transition by means of shaping national socio-technical systems and regimes. On this basis, we also discuss how to develop policies accelerating the transition. We find that the incumbent industries can shape policy choice through the lock-in into institutional inter-dependencies. The accumulation of social and material features, and vested interests of actors, for its part can maintain regime level inertia, impeding the transition. Yet, technological lock-in can also enable EVs, by means of learning effects from technologically interrelated wind energy projects and available infrastructure in buildings that support the EV charging needs. Overall, the complexity of path-dependent mechanisms embedded in the dominant regimes, together with the diversity of emerging policy mixes, demands attention both on the technologies and broader socio-technical systems in order to properly assess the prospects of transition toward electric mobility
Structural and luminescence characteristics of cycled submonolayer InAs/GaAs quantum dots with room-temperature emission at 1.3 μm
Quantum dots were grown by molecular beam epitaxy on GaAs substrates using a cycled submonolayer InAs/GaAs deposition technique. Their structural and luminescence characteristics have been compared with conventional self-organized dots. The room-temperature luminescence spectra are characterized by a ground state transition at 1.3 μm and additional transitions corresponding to excited states. Cross-sectional transmission electron microscopy indicates that no dislocations are formed if the total InAs thickness is less than 5–6 monolayers. Temperature dependence of the photoluminescence indicates that both types of quantum dots may have nonradiative defects, caused by segregation and related phenomena. © 1999 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70897/2/JAPIAU-86-11-6135-1.pd
Baryons in Holographic QCD
We study the baryon in holographic QCD with multi- brane
system. In holographic QCD, the baryon appears as a topologically non-trivial
chiral soliton in a four-dimensional effective theory of mesons. We call this
topological soliton as Brane-induced Skyrmion. Some review of
holographic QCD is presented from the viewpoints of recent hadron physics and
phenomenologies. Four-dimensional effective theory with pions and mesons
is uniquely derived from the non-abelian Dirac-Born-Infeld (DBI) action of
brane with supergravity background, without small amplitude expansion of
meson fields to discuss chiral solitons. For the hedgehog configuration of pion
and -meson fields, we derive the energy functional and the Euler-Lagrange
equation of Brane-induced Skyrmion from the meson effective action induced by
holographic QCD. Performing the numerical calculation, we obtain the pion
profile and the -meson profile of the Brane-induced
Skyrmion, and estimate its total energy, energy density distribution, and
root-mean-square radius. These results are compared with the experimental
quantities of baryons and also with the profiles of standard Skyrmion without
mesons. We analyze interaction terms of pions and mesons in
Brane-induced Skyrmion, and consider the role of -meson component
appearing in baryons.Comment: 28 pages, 11 figure
Increasing household toilet investments through CLUES: lessons from Ashaiman Municipal Assembly, Ghana
Community-Led Urban Environmental Sanitation (CLUES) is a planning approach piloted in Ghana as a sanitation demand creation and triggering method to increase household investment in toilet facilities. It is implemented by the Government of Ghana in Ashaiman Municipal Assembly with technical support from People’s Dialogue on Human Settlements and funding from UNICEF-Ghana. This paper provides results from the implementation process. Within a year of actual implementation, over 800 households in Ashaiman’s largely informal settlements expressed interest in sanitation investment with over 300 already with complete functional toilets
Brane-induced Skyrmion on S^3: baryonic matter in holographic QCD
We study baryonic matter in holographic QCD with D4/D8/\bar{D8} multi-D brane
system in type IIA superstring theory. The baryon is described as the
"brane-induced Skyrmion", which is a topologically non-trivial chiral soliton
in the four-dimensional meson effective action induced by holographic QCD. We
employ the "truncated-resonance model" approach for the baryon analysis,
including pion and \rho meson fields below the ultraviolet cutoff scale M_KK
\sim 1GeV, to keep the holographic duality with QCD. We describe the baryonic
matter in large N_c as single brane-induced Skyrmion on the three-dimensional
closed manifold S^3 with finite radius R. The interactions between baryons are
simulated by the curvature of the closed manifold S^3, and the decrease of the
size of S^3 represents the increase of the total baryon-number density in the
medium in this modeling. We investigate the energy density, the field
configuration, the mass and the root-mean-square radius of single baryon on S^3
as the function of its radius R. We find a new picture of "pion dominance" near
the critical density in the baryonic matter, where all the (axial) vector meson
fields disappear and only the pion field survive. We also find the "swelling"
phenomena of the baryons as the precursor of the deconfinement, and propose the
mechanism of the swelling in general context of QCD. The properties of the
deconfinement and the chiral symmetry restoration in the baryonic matter are
examined by taking the proper order parameters. We also compare our
truncated-resonance model with another "instanton" description of the baryon in
holographic QCD, considering the role of cutoff scale M_KK.Comment: 25 pages, 12 figure
Evaluation of serum iron overload, AST:ALT ratio and log10ferritin:AST ratio among schizophrenia patients in the Kumasi Metropolis, Ghana: A case-control study
Objective: The association between unbalanced iron indices and the conditions of schizophrenia are not well understood. Liver dysfunction which has been linked to iron metabolism might be a contributing factor. This case–control study evaluated serum iron indices and liver function in treatment-naïve schizophrenia patients and those already on treatment at the Psychiatric Department of the Komfo Anokye Teaching Hospital (KATH), Kumasi-Ghana.
Results: The mean age of the respondents was 39.6 ± 0.8 years. Increased levels of serum iron, TS, AST, ALT and AST:ALT ratio and lower levels of UIBC, TIBC, Transferrin, and log Ferritin:AST ratio levels were observed among the treatment-naïve group compared to the control. The treatment-naïve and treatment groups showed significantly higher serum AST:ALT ratio, and lower log10ferrtin:AST ratio than the healthy controls. There was a significant correlation between log10ferritin and AST, and log10ferritin and GGT in both treatments (r = 0.343; p = 0.003, and r = 0.502; p = 0.001 respectively) and treatment-naïve groups (r = 0.348; p = 0.002, and r = 0.614; p \u3c 0.001 respectively). Percentage transferrin saturation correlated significantly with GGT only, in the treatment-naïve group (r = 0.667; p \u3c 0.001), and ALT and GGT in the treatment group (r = 0.252; p = 0.030 and r = 0.646; p = 0.014 respectively)
Holographic chiral magnetic spiral
We study the ground state of baryonic/axial matter at zero temperature
chiral-symmetry broken phase under a large magnetic field, in the framework of
holographic QCD by Sakai-Sugimoto. Our study is motivated by a recent proposal
of chiral magnetic spiral phase that has been argued to be favored against
previously studied phase of homogeneous distribution of axial/baryonic currents
in terms of meson super-currents dictated by triangle anomalies in QCD. Our
results provide an existence proof of chiral magnetic spiral in strong coupling
regime via holography, at least for large axial chemical potentials, whereas we
don't find the phenomenon in the case of purely baryonic chemical potential.Comment: 24 pages, 15 figure
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