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Sipping Fuel and Saving Lives: Increasing Fuel Economy without Sacrificing Safety
Demonstrates how new fuel-efficiency technologies make it possible, and advisable, to significantly increase the fuel economy of motor vehicles without compromising their safety
Observation of Intensity Statistics of Light Transmitted Through 3D Random Media
We experimentally observe the spatial intensity statistics of light
transmitted through three-dimensional isotropic scattering media. The intensity
distributions measured through layers consisting of zinc oxide nanoparticles
differ significantly from the usual Rayleigh statistics associated with
speckle, and instead are in agreement with the predictions of mesoscopic
transport theory, taking into account the known material parameters of the
samples. Consistent with the measured spatial intensity fluctuations, the total
transmission fluctuates. The magnitude of the fluctuations in the total
transmission is smaller than expected on the basis of quasi-one-dimensional
(1D) transport theory, which indicates that quasi-1D theories cannot fully
describe these open three-dimensional media.Comment: 4 pages 3 figure
Probing the Cluster Mass Distribution using Subaru Weak Lensing Data
We present results from a weak lensing analysis of the galaxy cluster A1689
(z=0.183) based on deep wide-field imaging data taken with Suprime-Cam on
Subaru telescope. A maximum entropy method has been used to reconstruct
directly the projected mass distribution of A1689 from combined lensing
distortion and magnification measurements of red background galaxies.The
resulting mass distribution is clearly concentrated around the cD galaxy, and
mass and light in the cluster are similarly distributed in terms of shape and
orientation. The azimuthally-averaged mass profile from the two-dimensional
reconstruction is in good agreement with the earlier results from the Subaru
one-dimensional analysis of the weak lensing data, supporting the assumption of
quasi-circular symmetry in the projected mass distribution of the cluster.Comment: To appear in Mod. Phys. Lett. A, 8pages, 5 figures, minor typo errors
corrected, Fig.5 modifie
Radiative Transfer Effects during Photoheating of the Intergalactic Medium
The thermal history of the intergalactic medium (IGM) after reionization is
to a large extent determined by photoheating. Here we demonstrate that
calculations of the photoheating rate which neglect radiative transfer effects
substantially underestimate the energy input during and after reionization. The
neglect of radiative transfer effects results in temperatures of the IGM which
are too low by a factor of two after HeII reionization. We briefly discuss
implications for the absorption properties of the IGM and the distribution of
baryons in shallow potential wells.Comment: 4 pages, 2 figures, submitted to ApJ
Baryogenesis, Dark Matter and the Pentagon
We present a new mechanism for baryogenesis, which links the baryon asymmetry
of the universe to the dark matter density. The mechanism arises naturally in
the Pentagon model of TeV scale physics. In that context, it forces a
re-evaluation of some of the assumptions of the model, and we detail the
changes that are required in order to fit observations.Comment: JHEP3 LaTeX, 15 pages. New version corrects errors in the electroweak
baryon violating and matter radiation temperatures, which were pointed out by
the referee. Substantial quantitative but no qualitative change to our
conclusion
The Value of Online Information Privacy: An Empirical Investigation
Concern over online information privacy is widespread and rising. However, prior research is silent about the value of information privacy in the presence of potential benefits from sharing personally identifiable information. Analyzing individuals' trade-offs between the benefits and costs of providing personal information to websites revealed that benefits, monetary reward and future convenience, significantly affect individuals' preferences over websites with differing privacy policies. Quantifying the value of website privacy protection revealed that among U.S. subjects, protection against errors, improper access, and secondary use of personal information is worth US $30.49 - 44.62. Finally, three distinct segments of Internet consumers were determined: privacy guardians, information sellers and convenience seekers.
Numerical Simulations of High Redshift Star Formation in Dwarf Galaxies
We present first results from three-dimensional hydrodynamic simulations of
the high redshift formation of dwarf galaxies. The simulations use an Eulerian
adaptive mesh refinement technique to follow the non-equilibrium chemistry of
hydrogen and helium with cosmological initial conditions drawn from a popular
Lambda-dominated CDM model. We include the effects of reionization using a
uniform radiation field, a phenomenological description of the effect of star
formation and, in a separate simulation, the effects of stellar feedback. The
results highlight the effects of stellar feedback and photoionization on the
baryon content and star formation of galaxies with virial temperatures of
approximately 10^4K. Dwarf sized dark matter halos that assemble prior to
reionization are able to form stars. Most halos of similar mass that assemble
after reionization do not form stars by redshift of three. Dwarf galaxies that
form stars show large variations in their gas content because of stellar
feedback and photoionization effects. Baryon-to-dark matter mass ratios are
found to lie below the cosmic mean as a result of stellar feedback. The
supposed substructure problem of CDM is critically assessed on the basis of
these results. The star formation histories modulated by radiative and stellar
feedbacks are discussed. In addition, metallicities of individual objects are
shown to be naturally correlated with their mass-to-light ratios as is also
evident in the properties of local dwarf galaxies.Comment: 27 pages, 8 figures, accepted for publication in Ap
Systematic Review and Meta-analysis: Use of Statins Is Associated with a Reduced Incidence of Oesophageal Adenocarcinoma
Purpose: Laboratory studies have suggested that statins may have useful anti-cancer effects against Barrettâs epithelial cancer lines. A variety of effects have been reported in clinical studies. Methods: We performed a systematic review and meta-analysis of the association between statin use and the development of oesophageal cancer. Multiple databases were searched for studies reporting the association of statin use and oesophageal cancer. Meta-analysis on the relationship between statin use and cancer incidence was performed. Results: Twenty publications met eligibility criteria, yielding 22 datasets for meta-analysis. All were observational studies. Population-level studies included 372,206 cancer cases and 6,086,906 controls. Studies examining adenocarcinoma development in Barrettâs oesophagus included 1057 cancers and 17,741 controls. In patients with Barrettâs oesophagus, statin use was associated with a reduced incidence of adenocarcinoma (pooled adjusted odds ratio (OR) 0.59 (95% confidence intervals 0.50â0.68)), with no heterogeneity between 11 studies. Population-based studies demonstrated more heterogeneity but showed that statin use was associated with a lower incidence of both oesophageal adenocarcinoma (OR 0.57 (0.43â0.76)) and all oesophageal cancers (OR 0.82 (0.7â0.88)). Information on statin type, dose, and duration was reported too infrequently for statistical analysis but individual studies showed a tendency to a dose- and duration-dependant decrease in cancer incidence. Conclusions: Statin use is associated with a significantly lower incidence of oesophageal adenocarcinoma. This is seen in both Barrettâs cohorts and general populations. Further studies should focus on drug, dose, and duration and the interaction with other risk and preventative factors
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