Hand, foot and mouth disease in an immunocompetent adult due to Coxsackievirus A6

Hand, foot and mouth disease most commonly occurs in children less than 10 years old, but can occur in immunocompetent adults. We describe a 37-year-old immunocompetent man who presented with multiple painful papules and vesicles on his palms and feet together with vesicles inside the mouth. Real-time polymerase chain reaction revealed Coxsackievirus A6 in the vesicle fluid from the feet, throat swab, and rectal swab. Since the disease is highly contagious, to contain the infection it is prudent to recognise that hand, foot and mouth disease can occur in immunocompetent adults.published_or_final_versio

Formation of Globular Cluster Candidates in Merging Proto-galaxies at High Redshift: A View from the FIRE Cosmological Simulations

Using a state-of-the-art cosmological simulation of merging proto-galaxies at high redshift from the FIRE project, with explicit treatments of star formation and stellar feedback in the interstellar medium, we investigate the formation of star clusters and examine one of the formation hypothesis of present-day metal-poor globular clusters. We find that frequent mergers in high-redshift proto-galaxies could provide a fertile environment to produce long-lasting bound star clusters. The violent merger event disturbs the gravitational potential and pushes a large gas mass of ~> 1e5-6 Msun collectively to high density, at which point it rapidly turns into stars before stellar feedback can stop star formation. The high dynamic range of the reported simulation is critical in realizing such dense star-forming clouds with a small dynamical timescale, t_ff <~ 3 Myr, shorter than most stellar feedback timescales. Our simulation then allows us to trace how clusters could become virialized and tightly-bound to survive for up to ~420 Myr till the end of the simulation. Because the cluster's tightly-bound core was formed in one short burst, and the nearby older stars originally grouped with the cluster tend to be preferentially removed, at the end of the simulation the cluster has a small age spread.Comment: 14 pages, 14 figures, Accepted for publication in the Monthly Notices of the Royal Astronomical Society, High-resolution version of this article also available at http://www.jihoonkim.org/index/research.html#g

A Multicanonical Molecular Dynamics Study on a Simple Bead-Spring Model for Protein Folding

We have performed a multicanonical molecular dynamics simulation on a simple model protein.We have studied a model protein composed of charged, hydrophobic, and neutral spherical bead monomers.Since the hydrophobic interaction is considered to significantly affect protein folding, we particularly focus on the competition between effects of the Coulomb interaction and the hydrophobic interaction. We found that the transition which occurs upon decreasing the temperature is markedly affected by the change in both parameters and forms of the hydrophobic potential function, and the transition changes from first order to second order, when the Coulomb interaction becomes weaker.Comment: 7 pages, 6 postscript figures, To appear in J.Phys.Soc.Jpn. Vol.70 No.

Solar Neutron Events of October-November 2003

During the period when the Sun was intensely active on October-November 2003, two remarkable solar neutron events were observed by the ground-based neutron monitors. On October 28, 2003, in association with an X17.2 large flare, solar neutrons were detected with high statistical significance (6.4 sigma) by the neutron monitor at Tsumeb, Namibia. On November 4, 2003, in association with an X28 class flare, relativistic solar neutrons were observed by the neutron monitors at Haleakala in Hawaii and Mexico City, and by the solar neutron telescope at Mauna Kea in Hawaii simultaneously. Clear excesses were observed at the same time by these detectors, with the significance calculated as 7.5 sigma for Haleakala, and 5.2 sigma for Mexico City. The detector onboard the INTEGRAL satellite observed a high flux of hard X-rays and gamma-rays at the same time in these events. By using the time profiles of the gamma-ray lines, we can explain the time profile of the neutron monitor. It appears that neutrons were produced at the same time as the gamma-ray emission.Comment: 35 pages, 21 figures, accepted for publication in Ap

Critical Currents of Josephson-Coupled Wire Arrays

We calculate the current-voltage characteristics and critical current I_c^{array} of an array of Josephson-coupled superconducting wires. The array has two layers, each consisting of a set of parallel wires, arranged at right angles, such that an overdamped resistively-shunted junction forms wherever two wires cross. A uniform magnetic field equal to f flux quanta per plaquette is applied perpendicular to the layers. If f = p/q, where p and q are mutually prime integers, I_c^{array}(f) is found to have sharp peaks when q is a small integer. To an excellent approximation, it is found in a square array of n^2 plaquettes, that I_c^{array}(f) \propto (n/q)^{1/2} for sufficiently large n. This result is interpreted in terms of the commensurability between the array and the assumed q \times q unit cell of the ground state vortex lattice.Comment: 4 pages, 4 figure

Hydrogen atom in a spherical well: linear approximation

We discuss the boundary effects on a quantum system by examining the problem of a hydrogen atom in a spherical well. By using an approximation method which is linear in energy we calculate the boundary corrections to the ground-state energy and wave function. We obtain the asymptotic dependence of the ground-state energy on the radius of the well.Comment: Revised version to appear in European Journal of Physic