1,059 research outputs found
Machining properties of Melia dubia wood
In this paper result of working quality of Melia dubia was reported after testing them under six major wood working operations namely – planning, sanding, turning, shaping, boring and mortising based on Indian Standard IS 8292. The wood performed extremely well under planning. In shaping, the performance was good enough. Though all the other operations yielded poor results, the composite rating factor which is an overall performance indicator was 35 % more than that of Tectona grandis. The ease of working is only 93 % compared to teak. The working quality index which was based on the composite rating factor and ease of working worked out to 107 taking Tectona grandis as 100 mainly because of the high performance under planning and shaping and good performance under sanding
Tight-binding g-Factor Calculations of CdSe Nanostructures
The Lande g-factors for CdSe quantum dots and rods are investigated within
the framework of the semiempirical tight-binding method. We describe methods
for treating both the n-doped and neutral nanostructures, and then apply these
to a selection of nanocrystals of variable size and shape, focusing on
approximately spherical dots and rods of differing aspect ratio. For the
negatively charged n-doped systems, we observe that the g-factors for
near-spherical CdSe dots are approximately independent of size, but show strong
shape dependence as one axis of the quantum dot is extended to form rod-like
structures. In particular, there is a discontinuity in the magnitude of
g-factor and a transition from anisotropic to isotropic g-factor tensor at
aspect ratio ~1.3. For the neutral systems, we analyze the electron g-factor of
both the conduction and valence band electrons. We find that the behavior of
the electron g-factor in the neutral nanocrystals is generally similar to that
in the n-doped case, showing the same strong shape dependence and discontinuity
in magnitude and anisotropy. In smaller systems the g-factor value is dependent
on the details of the surface model. Comparison with recent measurements of
g-factors for CdSe nanocrystals suggests that the shape dependent transition
may be responsible for the observations of anomalous numbers of g-factors at
certain nanocrystal sizes.Comment: 15 pages, 6 figures. Fixed typos to match published versio
Shear Viscosity to Entropy Density Ratio in Six Derivative Gravity
We calculate shear viscosity to entropy density ratio in presence of four
derivative (with coefficient ) and six derivative (with coefficient
) terms in bulk action. In general, there can be three possible four
derivative terms and ten possible six derivative terms in the Lagrangian. Among
them two four derivative and eight six derivative terms are ambiguous, i.e.,
these terms can be removed from the action by suitable field redefinitions.
Rest are unambiguous. According to the AdS/CFT correspondence all the
unambiguous coefficients (coefficients of unambiguous terms) can be fixed in
terms of field theory parameters. Therefore, any measurable quantities of
boundary theory, for example shear viscosity to entropy density ratio, when
calculated holographically can be expressed in terms of unambiguous
coefficients in the bulk theory (or equivalently in terms of boundary
parameters). We calculate for generic six derivative gravity and find
that apparently it depends on few ambiguous coefficients at order .
We calculate six derivative corrections to central charges and and
express in terms of these central charges and unambiguous coefficients
in the bulk theory.Comment: 29 pages, no figure, V2, results and typos correcte
Vortex dynamics and upper critical fields in ultrathin Bi films
Current-voltage (I-V) characteristics of quench condensed, superconducting,
ultrathin films in a magnetic field are reported. These I-V's show
hysteresis for all films, grown both with and without thin underlayers.
Films on Ge underlayers, close to superconductor-insulator transition (SIT),
show a peak in the critical current, indicating a structural transformation of
the vortex solid (VS). These underlayers, used to make the films more
homogeneous, are found to be more effective in pinning the vortices. The upper
critical fields (B) of these films are determined from the resistive
transitions in perpendicular magnetic field. The temperature dependence of the
upper critical field is found to differ significantly from Ginzburg-Landau
theory, after modifications for disorder.Comment: Phys Rev B, to be published Figure 6 replaced with correct figur
Higher Derivative Corrections to Shear Viscosity from Graviton's Effective Coupling
The shear viscosity coefficient of strongly coupled boundary gauge theory
plasma depends on the horizon value of the effective coupling of transverse
graviton moving in black hole background. The proof for the above statement is
based on the canonical form of graviton's action. But in presence of generic
higher derivative terms in the bulk Lagrangian the action is no longer
canonical. We give a procedure to find an effective action for graviton (to
first order in coefficient of higher derivative term) in canonical form in
presence of any arbitrary higher derivative terms in the bulk. From that
effective action we find the effective coupling constant for transverse
graviton which in general depends on the radial coordinate . We also argue
that horizon value of this effective coupling is related to the shear viscosity
coefficient of the boundary fluid in higher derivative gravity. We explicitly
check this procedure for two specific examples: (1) four derivative action and
(2) eight derivative action ( term). For both cases we show that our
results for shear viscosity coefficient (up to first order in coefficient of
higher derivative term) completely agree with the existing results in the
literature.Comment: 0 + 23 page
Towards a Reference Model for a Productivity-Optimized Delivery of Technology Mediated Learning Services
Competition between two high- and low-affinity protein-binding sites in myosin VI controls its cellular function.
Myosin VI is involved in many cellular processes ranging from endocytosis to transcription. This multifunctional potential is achieved through alternative isoform splicing and through interactions of myosin VI with a diverse network of binding partners. However, the interplay between these two modes of regulation remains unexplored. To this end, we compared two different binding partners and their interactions with myosin VI by exploring the kinetic properties of recombinant proteins and their distribution in mammalian cells using fluorescence imaging. We found that selectivity for these binding partners is achieved through a high-affinity and a low-affinity motif within myosin VI. These two motifs allowed competition among partners for myosin VI. Exploring how this competition affects the activity of nuclear myosin VI, we demonstrate the impact of a concentration-driven interaction with the low-affinity binding partner DAB2, finding that this interaction blocks the ability of nuclear myosin VI to bind DNA and its transcriptional activity in vitro. We conclude that loss of DAB2, a tumor suppressor, may enhance myosin VI–mediated transcription. We propose that the frequent loss of specific myosin VI partner proteins during the onset of cancer leads to a higher level of nuclear myosin VI activity
The dynamics of quark-gluon plasma and AdS/CFT
In these pedagogical lectures, we present the techniques of the AdS/CFT
correspondence which can be applied to the study of real time dynamics of a
strongly coupled plasma system. These methods are based on solving
gravitational Einstein's equations on the string/gravity side of the AdS/CFT
correspondence. We illustrate these techniques with applications to the
boost-invariant expansion of a plasma system. We emphasize the common
underlying AdS/CFT description both in the large proper time regime where
hydrodynamic dynamics dominates, and in the small proper time regime where the
dynamics is far from equilibrium. These AdS/CFT methods provide a fascinating
arena interrelating General Relativity phenomenae with strongly coupled gauge
theory physics.Comment: 35 pages, 3 figures. Lectures at the 5th Aegean summer school, `From
gravity to thermal gauge theories: the AdS/CFT correspondence'. To appear in
the proceedings in `Lecture Notes in Physics
Reappraisal of the management of Vogt-Koyanagi-Harada disease: sunset glow fundus is no more a fatality.
Vogt-Koyanagi-Harada (VKH) disease is a primary autoimmune stromal choroiditis. Aim of the study was to gather a body of evidence from the literature and from experts that systemic corticosteroid combined with non-steroidal immunosuppressive therapy should become the standard of care in initial-onset VKH disease.
Literature was reviewed and leading experts in VKH were consulted in different parts of the world in order to put forward a consensus attitude in the management of initial-onset VKH disease.
There was a substantial body of evidence in the literature that early aggressive and sustained corticosteroid and non-steroidal immunosuppressive therapy in initial-onset VKH disease allows to achieve full control of choroidal inflammation, eliminating any subclinical choroidal inflammation, and substantially reduces recurrences with improvement of anatomical and functional outcomes. This was in agreement with experts' opinion and practice. ICGA was the method of choice to monitor disease evolution.
Since the choroidal space is easily accessible to systemic therapy and because inflammation in VKH disease is exclusively originating from the choroidal stroma, early and sustained treatment right at the onset of the disease process with dual corticosteroid and non-steroidal immunosuppressive therapy can result in full "healing" in many cases preventing sunset glow fundus which results from depigmentation from chronic uncontrolled inflammation
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