1,177 research outputs found
Flavour Democracy in Strong Unification
We show that the fermion mass spectrum may naturally be understood in terms
of flavour democratic fixed points in supersymmetric theories which have a
large domain of attraction in the presence of "strong unification". Our
approach provides an alternative to the approximate Yukawa texture zeroes of
the Froggatt-Nielsen mechanism. We discuss a particular model based on a broken
gauged family symmetry which illustrates our approach.Comment: 21 Pages plain latex; includes 5 eps figure
Increased dissolution rates of tranilast solid dispersions extruded with inorganic excipients
The purpose of this study was to evaluate the performance of NeusilinÂź (NEU) a synthetic magnesium aluminometasilicate as inorganic drug carrier co-processed with the hydrophilic surfactants Labrasol and Labrafil to develop Tranilast (TLT) based solid dispersions using continuous melt extrusion (HME) processing. Twin â screw extrusion was optimized to develop various TLT/excipient/surfactant formulations followed by continuous capsule filling in the absence of any downstream equipment. Physicochemical characterisation showed the existence of TLT in partially crystalline state in the porous network of inorganic NEU for all extruded formulations. Furthermore, the in line NIR studies revealed a possible intermolecular Hâbonding formation between the drug and carrier resulting in the increase of dissolution of TLT. The capsules containing TLT extruded solid dispersions showed enhanced dissolution rates and compared with the marketed RizabenÂź product
Virtopsy: ZukunftstrÀchtige Forschung in der Rechtsmedizin
Computed tomography techniques have been developed over the last 10 years and have found various applications in the forensic field. The most recent development is multislice computed tomography combined with photogrammetry-based surface optical scanning and image rendering techniques. This combination of techniques can be used to produce 3-dimensional images of injury patterns for comparison with suspect weapons and also to screen for pathological conditions in the living or deceased. This technology provides a minimally invasive procedure for capturing forensically relevant images which can be produced in the courtroom. The rapid developments in imaging techniques could provide an alternative to conventional autopsy procedures in the futur
Real time response on dS_3: the Topological AdS Black Hole and the Bubble
We study real time correlators in strongly coupled N=4 supersymmetric
Yang-Mills theory on dS_3 x S^1, with antiperiodic boundary conditions for
fermions on the circle. When the circle radius is larger than a critical value,
the dual geometry is the so-called "topological AdS_5 black hole". Applying the
Son- Starinets recipe in this background we compute retarded glueball
propagators which exhibit an infinite set of poles yielding the quasinormal
frequencies of the topological black hole. The imaginary parts of the
propagators exhibit thermal effects associated with the Gibbons-Hawking
temperature due to the cosmological horizon of the de Sitter boundary. We also
obtain R-current correlators and find that after accounting for a small
subtlety, the Son-Starinets prescription yields the retarded Green's functions.
The correlators do not display diffusive behaviour at late times. Below the
critical value of the circle radius, the topological black hole decays to the
AdS_5 "bubble of nothing". Using a high frequency WKB approximation, we show
that glueball correlators in this phase exhibit poles on the real axis. The
tunnelling from the black hole to the bubble is interpreted as a hadronization
transition.Comment: 52 pages, 11 figures, typos corrected, references adde
Incorporating Structural Analysis in a Quantum Dot Monte-Carlo Model
We simulate the shape of the density of states (DoS) of the quantum dot (QD) ensemble based upon size information provided by high angle annular dark field scanning transmission electron microscopy (HAADF STEM). We discuss how the capability to determined the QD DoS from micro-structural data allows a MonteCarlo model to be developed to accurately describe the QD gain and spontaneous emission spectra. The QD DoS shape is then studied, with recommendations made via the effect of removing, and enhancing this size inhomogeneity on various QD based devices is explored
High-precision calculations of van der Waals coefficients for heteronuclear alkali-metal dimers
Van der Waals coefficients for the heteronuclear alkali-metal dimers of Li,
Na, K, Rb, Cs, and Fr are calculated using relativistic ab initio methods
augmented by high-precision experimental data. We argue that the uncertainties
in the coefficients are unlikely to exceed about 1%.Comment: 11 pages, 2 figs, graphicx.st
A new approach to constructing models of electron diffusion by EMIC waves in the radiation belts
Electromagnetic Ion Cyclotron (EMIC) waves play an important role in relativistic electron losses in the radiation belts through diffusion via resonant waveâparticle interactions. We present a new approach for calculating bounce and driftâaveraged EMIC electron diffusion coefficients. We calculate bounceâaveraged diffusion coefficients, using quasiâlinear theory, for each individual CRRES EMIC wave observation using fitted wave properties, the plasma density and the background magnetic field. These calculations are then combined into bounceâaveraged diffusion coefficients. The resulting coefficients therefore capture the combined effects of individual spectra and plasma properties as opposed to previous approaches that use average spectral and plasma properties, resulting in diffusion over a wider range of energies and pitchâangles. These calculations, and their role in radiation belt simulations, are then compared against existing diffusion models. The new diffusion coefficients are found to significantly improve the agreement between the calculated decay of relativistic electrons and Van Allen Probes data
A Lifshitz Black Hole in Four Dimensional R^2 Gravity
We consider a higher derivative gravity theory in four dimensions with a
negative cosmological constant and show that vacuum solutions of both Lifshitz
type and Schr\"{o}dinger type with arbitrary dynamical exponent z exist in this
system. Then we find an analytic black hole solution which asymptotes to the
vacuum Lifshitz solution with z=3/2 at a specific value of the coupling
constant. We analyze the thermodynamic behavior of this black hole and find
that the black hole has zero entropy while non-zero temperature, which is very
similar to the case of BTZ black holes in new massive gravity at a specific
coupling. In addition, we find that the three dimensional Lifshitz black hole
recently found by E. Ayon-Beato et al. has a negative entropy and mass when the
Newton constant is taken to be positive.Comment: 11 pages, no figure; v2, a minor error correcte
Some No-go Theorems for String Duals of Non-relativistic Lifshitz-like Theories
We study possibilities of string theory embeddings of the gravity duals for
non-relativistic Lifshitz-like theories with anisotropic scale invariance. We
search classical solutions in type IIA and eleven-dimensional supergravities
which are expected to be dual to (2+1)-dimensional Lifshitz-like theories.
Under reasonable ansaetze, we prove that such gravity duals in the
supergravities are not possible. We also discuss a possible physical reason
behind this.Comment: 18 pages, Latex, flux conditions clarified (v2), brief summary of
results added (v3
Characterizing RadiationâBelt Energetic Electron Precipitation Spectra: A Comparison of QuasiâLinear Diffusion Theory With In Situ Measurements
High energy electron precipitation from the Earth's radiation belts is important for loss from the radiation belts and atmospheric chemistry. We follow up investigations presented in Reidy et al. (2021, https://doi.org/10.1029/2020ja028410) where precipitating flux is calculated inside the field of view of the POES T0 detector using quasi-linear theory and pitch angle diffusion coefficients (Dαα) from the British Antarctic Survey (BAS). These results showed good agreements at >30 keV for L* >5 on the dawnside but the flux were too low at higher energies. We have investigated the effect of changing parameters in the calculation of the precipitating flux to improve the results for the higher energies using comparisons of in situ flux and cold plasma measurements from GOES-15 and RBSP. We find that the strength of the diffusion coefficients rather than the shape of the source spectrum has the biggest effect on the calculated precipitation. In particular we find decreasing the cold plasma density used in the calculation of Dαα increases the diffusion and hence the precipitation at the loss cone for the higher energies, improving our results. The method of calculating Dαα is also examined, comparing co-located rather than averaged RBSP measurements. We find that the method itself has minimal effect but using RBSP derived Dαα improved our results over using Dαα calculated using the entire BAS wave data base; this is potentially due to better measurements of the cold plasma density from RBSP than the other spacecraft included in the BAS wave data base (e.g., THEMIS)
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