The calibration of photographic and spectroscopic films: Reciprocity failure and thermal responses of IIaO film at liquid nitrogen temperatures

Reciprocity failure was examined for IIaO spectroscopic film. The results indicate reciprocity failure occurs at three distinct minimum points in time; 15 min, 30 min and 90 min. The results are unique because theory suggests only one minimum reciprocity failure point should occur. When incubating 70mm IIaO film for 15 and 30 min at temperatures of 30, 40, 50, and 60 C and then placing in a liquid nitrogen bath at a temperature of -190 C the film demonstrated an increase of the optical density when developed at a warm-up time of 30 min. Longer warm-up periods of 1, 2 and 3 hrs yield a decrease in optical density of the darker wedge patterns; whereas, shorter warm-up times yield an overall increase in the optical densities

Classical Stabilization of Homogeneous Extra Dimensions

If spacetime possesses extra dimensions of size and curvature radii much larger than the Planck or string scales, the dynamics of these extra dimensions should be governed by classical general relativity. We argue that in general relativity, it is highly nontrivial to obtain solutions where the extra dimensions are static and are dynamically stable to small perturbations. We also illustrate that intuition on equilibrium and stability built up from non-gravitational physics can be highly misleading. For all static, homogeneous solutions satisfying the null energy condition, we show that the Ricci curvature of space must be nonnegative in all directions. Much of our analysis focuses on a class of spacetime models where space consists of a product of homogeneous and isotropic geometries. A dimensional reduction of these models is performed, and their stability to perturbations that preserve the spatial symmetries is analyzed. We conclude that the only physically realistic examples of classically stabilized large extra dimensions are those in which the extra-dimensional manifold is positively curved.Comment: 25 pages; minor changes, improved reference

Flux Compactifications: Stability and Implications for Cosmology

We study the dynamics of the size of an extra-dimensional manifold stabilised by fluxes. Inspecting the potential for the 4D field associated with this size (the radion), we obtain the conditions under which it can be stabilised and show that stable compactifications on hyperbolic manifolds necessarily have a negative four-dimensional cosmological constant, in contradiction with experimental observations. Assuming compactification on a positively curved (spherical) manifold we find that the radion has a mass of the order of the compactification scale, M_c, and Planck suppressed couplings. We also show that the model becomes unstable and the extra dimensions decompactify when the four-dimensional curvature is higher than a maximum value. This in particular sets an upper bound on the scale of inflation in these models: V_max \sim M_c^2 M_P^2, independently of whether the radion or other field is responsible for inflation. We comment on other possible contributions to the radion potential as well as finite temperature effects and their impact on the bounds obtained.Comment: 16 pages, 1 figure, LaTeX; v2: typos fixed and references adde

Cosmology of codimension-two braneworlds

We present a comprehensive study of the cosmological solutions of 6D braneworld models with azimuthal symmetry in the extra dimensions, moduli stabilization by flux or a bulk scalar field, and which contain at least one 3-brane that could be identified with our world. We emphasize an unusual property of these models: their expansion rate depends on the 3-brane tension either not at all, or in a nonstandard way, at odds with the naive expected dimensional reduction of these systems to 4D general relativity at low energies. Unlike other braneworld attempts to find a self-tuning solution to the cosmological constant problem, the apparent failure of decoupling in these models is not associated with the presence of unstabilized moduli; rather it is due to automatic cancellation of the brane tension by the curvature induced by the brane. This provides some corroboration for the hope that these models provide a distinctive step toward understanding the smallness of the observed cosmological constant. However, we point out some challenges for obtaining realistic cosmology within this framework.Comment: 30 pages, 4 figures; generalized result for nonconventional Friedmann equation, added referenc

Population Frequencies Determined by Next-generation Sequencing Provide Strategies for Prospective HLA Epitope Matching for Transplantation

Compatibility for human leukocyte antigen (HLA) genes between transplant donors and recipients improves graft survival but prospective matching is rarely performed due to the vast heterogeneity of this gene complex. To reduce complexity, we have combined next-generation sequencing and in silico mapping to determine population frequencies and matching probabilities of 150 antibody-binding eplets across all 11 classical HLA genes in 2000 ethnically heterogeneous renal patients and donors. We show that eplets are more common and more uniformly distributed between donors and recipients than the respective HLA isoforms. Simulation of targeted eplet matching shows that a high degree of overall compatibility, and perfect identity at the clinically important HLA class II loci, can be obtained within a patient waiting list of approximately 250 subjects. Internal epitope-based allocation is thus feasible for most major renal transplant programs, while regional or national sharing may be required for other solid organs

Work and heat fluctuations in two-state systems: a trajectory thermodynamics formalism

Two-state models provide phenomenological descriptions of many different systems, ranging from physics to chemistry and biology. We investigate work fluctuations in an ensemble of two-state systems driven out of equilibrium under the action of an external perturbation. We calculate the probability density P(W) that a work equal to W is exerted upon the system along a given non-equilibrium trajectory and introduce a trajectory thermodynamics formalism to quantify work fluctuations in the large-size limit. We then define a trajectory entropy S(W) that counts the number of non-equilibrium trajectories P(W)=exp(S(W)/kT) with work equal to W. A trajectory free-energy F(W) can also be defined, which has a minimum at a value of the work that has to be efficiently sampled to quantitatively test the Jarzynski equality. Within this formalism a Lagrange multiplier is also introduced, the inverse of which plays the role of a trajectory temperature. Our solution for P(W) exactly satisfies the fluctuation theorem by Crooks and allows us to investigate heat-fluctuations for a protocol that is invariant under time reversal. The heat distribution is then characterized by a Gaussian component (describing small and frequent heat exchange events) and exponential tails (describing the statistics of large deviations and rare events). For the latter, the width of the exponential tails is related to the aforementioned trajectory temperature. Finite-size effects to the large-N theory and the recovery of work distributions for finite N are also discussed. Finally, we pay particular attention to the case of magnetic nanoparticle systems under the action of a magnetic field H where work and heat fluctuations are predicted to be observable in ramping experiments in micro-SQUIDs.Comment: 28 pages, 14 figures (Latex

Crossover from thermal hopping to quantum tunneling in Mn_{12}Ac

The crossover from thermal hopping to quantum tunneling is studied. We show that the decay rate $\Gamma$ with dissipation can accurately be determined near the crossover temperature. Besides considering the Wentzel-Kramers-Brillouin (WKB) exponent, we also calculate contribution of the fluctuation modes around the saddle point and give an extended account of a previous study of crossover region. We deal with two dangerous fluctuation modes whose contribution can't be calculated by the steepest descent method and show that higher order couplings between the two dangerous modes need to be taken into considerations. At last the crossover from thermal hopping to quantum tunneling in the molecular magnet Mn_{12}Ac is studied.Comment: 10 pages, 3 figure

Demonstration of Enhanced Radiation Drive in Hohlraums Made with High-Z Mixture "Cocktail" Wall Material

We present results from experiments, numerical simulations and analytic modeling, demonstrating enhanced hohlraum performance. Care in the fabrication and handling of hohlraums with walls consisting of high-Z mixtures (cocktails) has led to our demonstration, for the first time, of a significant increase in radiation temperature compared to a pure Au hohlraum that is in agreement with predictions and is ascribable to reduced wall losses. This data suggests that a NIF ignition hohlraum made of a U:Au:Dy cocktail should have {approx}17% reduction in wall losses compared to a similar gold hohlraum

High sensitivity GEM experiment on double beta decay of 76-Ge

The GEM project is designed for the next generation 2 beta decay experiments with 76-Ge. One ton of ''naked'' HP Ge detectors (natural at the first GEM-I phase and enriched in 76-Ge to 86% at the second GEM-II stage) are operating in super-high purity liquid nitrogen contained in the Cu vacuum cryostat (sphere with diameter 5 m). The latest is placed in the water shield. Monte Carlo simulation evidently shows that sensitivity of the experiment (in terms of the T1/2 limit for neutrinoless 2 beta decay) is 10^27 yr with natural HP Ge crystals and 10^28 yr with enriched ones. These bounds corresponds to the restrictions on the neutrino mass less than 0.05 eV and 0.015 eV with natural and enriched detectors, respectively. Besides, the GEM-I set up could advance the current best limits on the existence of neutralinos - as dark matter candidates - by three order of magnitudes, and at the same time would be able to identify unambiguously the dark matter signal by detection of its seasonal modulation.Comment: LaTeX, 20 pages, 4 figure

Enchanced hohlraum radiation drive through reduction of wall losses with high-Z mixture "cocktail" wall materials

We present results from experiments, numerical simulations and analytic modeling, demonstrating enhanced hohlraum performance. Care in the fabrication and handling of hohlraums with walls consisting of high-Z mixtures (cocktails) has led to our demonstration, for the first time, of a significant increase in radiation temperature (up to +7eV at 300 eV) compared to a pure Au hohlraum, in agreement with predictions and ascribable to reduced wall losses. The data extrapolated to full NIF suggest we can expect an 18% reduction in wall loss for the current ignition design by switching to cocktail hohlraums, consistent with requirements for ignition with 1MJ laser energy