Gamma-Rays from Large Scale Structure Formation and the Warm-Hot Intergalactic Medium: Cosmic Baryometry with Gamma-Rays

It is shown that inverse Compton gamma-rays from electrons accelerated in large scale structure formation shocks can be crucially affected by non-gravitational effects such as radiative cooling and galaxy formation, with corresponding uncertainties by an order of magnitude in either the gamma-ray source counts or the extragalactic background contribution. However, this also implies that such gamma-rays may in the near future provide us with valuable information about the fraction of cosmic baryons in different forms, particularly the warm-hot intergalactic medium where the majority of the baryons in the universe are believed to reside. We address this problem in a simple way through semi-analytic modeling of structure formation shocks which self-consistently treats merger and accretion shocks.Comment: 7 pages, 2 figures; slightly modified version of article to appear in Proc. of the "International Symposium on High Energy Gamma-Ray Astronomy" Heidelberg (2004), eds. F.A. Aharonian, H.J. Voelk and D. Horns (AIP, NY

Arailability and Limitation of Multiplicity Measurements in the NM-64 Neutron Monitor at Syowa Station, Antarctica

Multiplicity measurements using the NM-64 neutron monitor have been carried out continuously at Syowa Station, Antarctica, and concurrently once a year along a definite sea-level route between Japan and Syowa Station. The Syowa data obtained during the period from March 1967 to February 1969 are analyzed, together with those from the first two of the latitude surveys which are in progress since 1966. The barometric coefficient and the rigidity response function of the cosmic-ray neutron component are derived as a function of multiplicities from m=1 to m≥6. The multiplicity spectrum is investigated in the cases of the cosmic modulation phenomena such as solar proton event, Forbush decrease and diurnal variation. It is shown that the barometric coefficients and the magnitudes of intensity variations as observed in the solar proton and Forbush decrease events are decreasing with increasing multiplicity, while no significant multiplicity effect is recognized in the diurnal variation. A possibility of distinguishing the various modulation spectra of the primary cosmic radiation on the basis of the multiplicity measurements is examined quantitatively. By taking into account the behavior of higher multiplicities and the accuracy in low rigidity part of the differential response functions, the limitation of the NM-64 neutron monitor in the multiplicity work is discussed

Abnormality of apico–basal polarity in adenocarcinoma

Apico–basal polarity is a fundamental property of the epithelium that functions as a barrier, holds cells together, and determines the directions of absorption and secretion. Apico–basal polarity is regulated by extracellular matrix-integrin binding and downstream signaling pathways, including focal adhesion kinase, rouse-sarcoma oncogene (SRC), and RHO/RHO-associated kinase (ROCK). Loss of epithelial cell polarity plays a critical role in the progression of cancer cells. However, in differentiated carcinomas, polarity is not completely lost but dysregulated. Recent progress with a three-dimensional culture of primary cancer cells allowed for studies of the mechanism underlying the abnormality of polarity in differentiated cancers, including flexible switching of polarity status in response to the microenvironment. Invasive micropapillary carcinoma (MPC) is one of the histopathological phenotypes of adenocarcinoma, which is characterized by inverted polarity. Aberrant activation of RHO–ROCK signaling plays a critical role in the MPC phenotype. Establishing in vitro models will contribute to future drug targeting of the abnormal polarity status in cancer

Analytic Approach to the Cloud-in-cloud Problem for Non-Gaussian Density Fluctuations

We revisit the cloud-in-cloud problem for non-Gaussian density fluctuations. We show that the extended Press-Schechter (EPS) formalism for non-Gaussian fluctuations has a flaw in describing mass functions regardless of type of filtering. As an example, we consider non-Gaussian models in which density fluctuations at a point obeys a \chi^2 distribution with \nu degrees of freedom. We find that mass functions predicted by using an integral formula proposed by Jedamzik, and Yano, Nagashima and Gouda, properly taking into account correlation between objects at different scales, deviate from those predicted by using the EPS formalism, especially for strongly non-Gaussian fluctuations. Our results for the mass function at large mass scales are consistent with those by Avelino and Viana obtained from numerical simulations.Comment: 10 pages, 7 EPS files, submitted to Ap

Study on the Production of Flaky Amorphous Alloy Powders by Impact Flattening of Atomized Liquid Droplets on a Rapidly Rotating Wheel

A two-stage quenching technique consisting of impact flattening of atomized supercooled liquid droplets caused the production of flaky amorphous powders with a thickness of 1 to 3μm and an aspect ratio of 20 to 300 in Co-, Fe- and Al-based systems. The flaky powders consist of an amorphous phase over the entire particle size range even in the alloy systems where no amorphous phase is formed in the particle size below 25μm by high-pressure gas atomization. The improvement of the production ratio of the amorphous powders is due to the following three factors; (1) the second-stage cooling of supercooled liquid droplets, (2) the reduction of powder thickness to 1 to 3μm, and (3) the high thermal conductive state between rotator and powder resulting from the high-energy collision. The flaky powders also have smooth surface and edge combined with a uniform thickness, leading to good luster, high reflection ratio against light, high corrosion resistance, high mechanical strength and anisotropic magnetic properties. Furthermore, the unique morphology causes a high laminating tendency in a resin. By utilizing these advantages, the flaky amorphous powders are expected to be used as magnetic filler and corrosion-resistant coating materials

Methane Concentration at Heading Faces With Auxiliary Ventilation

Three-dimensional airflow velocities at a heading face by a forcing or exhausting auxiliary ventilation system were measured in an actual size model gallery and in an actual mine. There were several stagnated regions near the roof comer, which might have danger of methane accumulation. Airflow velocities by an exhausting system were much smaller than that by a forcing system. The airflow and methane concentrations by a forcing, exhausting, or combined system were examined using a visualization technique by laser light in a reduced scale model. Water was used instead of air and very fine bubbles generated by electrolysis were employed as tracer. The behavior of the bubbles in water is similar to that of methane in the air. Accumulation of bubbles was observed at the roof comer of the face which corresponds to the region that the airflow stagnation was observed in the previous actual size model experiment. The optimal airflow rate through a forcing and exhaust duct and duct end locations to reduce hazard of methane accumulation were investigated for the combined system of ventilation. Experiments on methane accumulation using real methane in the air were also conducted in other reduced scale model

Enhanced Raman scattering by dielectric spheres

Abstract -A phenomenon of local field enhancement by dielectric spheres is reviewed. Interaction with surface plasmon polariton of metal substrate is discussed. Especially, a system of a two-dimensional array of spheres placed on a flat substrate is discussed in detail. The obtained features of the resonance modes are shown to be quite general and various possibilities for the application in non-linear optics are suggested