760 research outputs found
Kawasaki disease and ENSO-driven wind circulation
Kawasaki disease (KD) is the most common cause of acquired heart disease in children worldwide. Recently, a climatological study suggested that KD may be triggered by a windborne agent traveling across the north Pacific through the westerly wind flow prevailing at midlatitudes. Here we use KD records to describe the association between enhanced disease activity on opposite sides of the basin and different phases of the El Niño-Southern Oscillation (ENSO) phenomenon, via the linkage to these tropospheric winds. Results show that years with higher-than-normal KD cases in Japan preferentially occur during either El Niño Modoki or La Niña conditions, while in San Diego during the mature phase of El Niño or La Niña events. Given that ENSO offers a degree of predictability at lead times of 6 months, these modulations suggest that seasonal predictions of KD could be used to alert clinicians to periods of increased disease activity
Phosphorous Diffuser Diverged Blue Laser Diode for Indoor Lighting and Communication.
An advanced light-fidelity (Li-Fi) system based on the blue Gallium nitride (GaN) laser diode (LD) with a compact white-light phosphorous diffuser is demonstrated for fusing the indoor white-lighting and visible light communication (VLC). The phosphorous diffuser adhered blue GaN LD broadens luminescent spectrum and diverges beam spot to provide ample functionality including the completeness of Li-Fi feature and the quality of white-lighting. The phosphorous diffuser diverged white-light spot covers a radiant angle up to 120(o) with CIE coordinates of (0.34, 0.37). On the other hand, the degradation on throughput frequency response of the blue LD is mainly attributed to the self-feedback caused by the reflection from the phosphor-air interface. It represents the current state-of-the-art performance on carrying 5.2-Gbit/s orthogonal frequency-division multiplexed 16-quadrature-amplitude modulation (16-QAM OFDM) data with a bit error rate (BER) of 3.1 × 10(-3) over a 60-cm free-space link. This work aims to explore the plausibility of the phosphorous diffuser diverged blue GaN LD for future hybrid white-lighting and VLC systems
A Primary Study of Heavy Baryons Lambda_Q, Xi_Q, Sigma_Q and Omega_Q
We perform a preliminary study of the 1/2+ and 3/2+ ground-state baryons
containing a heavy quark in the framework of the chiral SU(3) quark model. By
using the calculus of variations, masses of Lambda_Q, Sigma_Q, Xi_Q, Omega_Q,
Sigma_Q^*, Xi_Q^* and Omega_Q^*, where Q means c or b quark, are calculated.
With taking reasonable model parameters, the numerical results of established
heavy baryons are generally in agreement with the available experimental data,
except that those of Xi_Q are somewhat heavier. For Omega_b with undetermined
experimental mass and nobserved Xi_b^*, Omega_b^*, reasonable theoretical
predictions are obtained. Interactions inside baryons are also discussed.Comment: 5 page
Erosion and Sedimentation During the September 2015 Flooding of the Kinu River, Central Japan
Erosional and sedimentary features associated with flooding have been documented in both modern and past cases. However, only a few studies have demonstrated the relationship between these features and the corresponding hydraulic conditions that produced them, making it difficult to evaluate the magnitude of paleo-flooding. This study describes the characteristics associated with inundation depth and flow direction, as well as the erosional and sedimentary features resulting from the disastrous flooding of the Kinu River, central Japan, in September 2015. Water levels rose rapidly due to heavy rainfall that eventually overtopped, and subsequently breached, a levee in Joso City, causing destructive flooding on the surrounding floodplain. Distinctive erosional features are found next to the breached levee, while depositional features, such as a sandy crevasse-splay deposit are found further away from the breach. The deposit can be divided into three units based on sedimentary facies. The vertical and lateral changes of these sedimentary facies may be the result of temporal and spatial changes associated with flow during the single flooding event. These observations and quantitative data provide information that can be used to reveal the paleohydrology of flood deposits in the stratigraphic record, leading to improved mitigation of future flooding disasters
Substitutional doping of Cu in diamond: Mott physics with orbitals
Discovery of superconductivity in the impurity band formed by heavy doping of
boron into diamond (C:B) as well as doping of boron into silicon (Si:B) has
provided a rout for the possibility of new families of superconducting
materials. Motivated by the special role played by copper atoms in high
temperature superconducting materials where essentially Cu orbitals are
responsible for a variety of correlation induced phases, in this paper we
investigate the effect of substitutional doping of Cu into diamond. Our
extensive first principle calculations averaged over various geometries based
on density functional theory, indicates the formation of a mid-gap band, which
mainly arises from the and states of Cu. For impurity
concentrations of more than 2pt_{2g}4p\sim 5%, completely closes the
spectral gap of the host diamond.Comment: 5 figure
Book Reviews
Book Reviews: Ha'ena: Through the Eyes of the Ancestors by Carlos Andrade ; Ben: A Memoir, From Street Kid to Governor by Benjamin J. Cayetano ; Asian Settler Colonialism: From Local Governance to the Habits of Everyday Life in Hawai'i edited by Candace Fujikane and Jonathan Y. Okamura ; Encyclopedia of Islands edited by Rosemary G. Gillespie and David A. Clague ; The Healthy Ancestor: Embodied Inequality and the Revitalization of Native Hawaiian Health by Juliet McMullin ; Alexander Cartwright: The Life Behind the Baseball Legend by Monica Nucciarone ; Island World: A History of Hawai'i and the United States by Gary Y. Okihiro ; A Japanese Robinson Crusoe by Jenichiro Oyabe and edited by Greg Robinson and Yujin Yaguchi ; A Tragedy of Democracy: Japanese Confinement in North America by Greg Robinso
Particle Physics Implications for CoGeNT, DAMA, and Fermi
Recent results from the CoGeNT collaboration (as well as the annual
modulation reported by DAMA/LIBRA) point toward dark matter with a light (5-10
GeV) mass and a relatively large elastic scattering cross section with nucleons
(\sigma ~ 10^{-40} cm^2). In order to possess this cross section, the dark
matter must communicate with the Standard Model through mediating particles
with small masses and/or large couplings. In this Letter, we explore with a
model independent approach the particle physics scenarios that could
potentially accommodate these signals. We also discuss how such models could
produce the gamma rays from the Galactic Center observed in the data of the
Fermi Gamma Ray Space Telescope. We find multiple particle physics scenarios in
which each of these signals can be accounted for, and in which the dark matter
can be produced thermally in the early Universe with an abundance equal to the
measured cosmological density.Comment: 4 pages, 2 figure
Numerical studies on supersonic spray combustion in high-temperature shear flows in a scramjet combustor
Numerical simulation is applied to detail the combustion characteristics of n-decane sprays in highly compressible vortices formed in a supersonic mixing layer. The multi-phase reacting flow is modeled, in which the shear flow is solved Eulerianly by means of direct numerical simulation, and the motions of individual sub-grid point-mass fuel droplets are tracked Lagrangianly. Spray combustion behaviors are studied under different ambient pressures. Results indicate that ignition kernels are formed at high-strain vortex braids, where the scalar dissipation rates are high. The flame kernels are then strongly strained, associated with the rotation of the shearing vortex, and propagate to envelop the local vortex. It is observed that the flammable mixtures entrained in the vortex are burned from the edge to the core of the vortex until the reactants are completely consumed. As the ambient pressure increases, the high-temperature region expands so that the behaviors of spray flames are strongly changed. An overall analysis of the combustion field indicates that the time-averaged temperature increases, and the fluctuating pressure decreases, resulting in a more stable spray combustion under higher pressures, primarily due to the acceleration of the chemical reaction
The SN 393 -- SNR RX J1713.7-3946 (G347.3-0.5) Connection
Although the connection of the Chinese "guest" star of 393 AD with the
Galactic supernova remnant RX J1713.7-3946 (G347.3-0.5) made by Wang et al. in
1997 is consistent with the remnant's relatively young properties and the guest
star's projected position within the `tail' of the constellation Scorpius,
there are difficulties with such an association. The brief Chinese texts
concerning the 393 AD guest star make no comment about its apparent brightness
stating only that it disappeared after 8 months. However, at the remnant's
current estimated 1 - 1.3 kpc distance and A_v ~ 3 mag, its supernova should
have been a visually bright object at maximum light (-3.5 to -5.0 mag) and
would have remained visible for over a year. The peak brightness ~ 0 magnitude
adopted by Wang et al. and others would require the RX J1713.7-3946 supernova
to have been a very subluminous supernova event similar to or fainter than
CCSNe like SN 2005cs. We also note problems connecting SN 393 with a European
record in which the Roman poet Claudian describes a visually brilliant star in
the heavens around 393 AD that could be readily seen even in midday. Although
several authors have suggested this account may be a reference to the Chinese
supernova of 393, Scorpius would not be visible near midday in March when the
Chinese first reported the 393 guest star. We review both the Chinese and Roman
accounts and calculate probable visual brightnesses for a range of supernova
subtypes and conclude that neither the Chinese nor the Roman descriptions are
easily reconciled with an expected RX J1713.7-3946 supernova brightness and
duration.Comment: 7 pages includes 2 tables. Accepted for publication in AJ. Revised
text regarding subluminous SN
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