578 research outputs found
Thermal Conductivity of the Pyrochlore Superconductor KOs2O6: Strong Electron Correlations and Fully Gapped Superconductivity
To elucidate the nature of the superconducting ground state of the
geometrically frustrated pyrochlore KOs2O6 (Tc=9.6K), the thermal conductivity
was measured down to low temperatures (~Tc/100). We found that the
quasiparticle mean free path is strikingly enhanced below a transition at
Tp=7.5K, indicating enormous electron inelastic scattering in the normal state.
In a magnetic field the conduction at T ->0K is nearly constant up to ~0.4Hc2,
in contrast with the rapid growth expected for superconductors with an
anisotropic gap. This unambiguously indicates a fully gapped superconductivity,
in contrast to the previous studies. These results highlight that KOs2O6 is
unique among superconductors with strong electron correlations.Comment: 5 pages, 4 figures, accepted for publication in Phys. Rev. Let
Mie-resonances, infrared emission and band gap of InN
Mie resonances due to scattering/absorption of light in InN containing
clusters of metallic In may have been erroneously interpreted as the infrared
band gap absorption in tens of papers. Here we show by direct thermally
detected optical absorption measurements that the true band gap of InN is
markedly wider than currently accepted 0.7 eV. Micro-cathodoluminescence
studies complemented by imaging of metallic In have shown that bright infrared
emission at 0.7-0.8 eV arises from In aggregates, and is likely associated with
surface states at the metal/InN interfaces.Comment: 4 pages, 5 figures, submitted to PR
Phonon Dynamics and Multipolar Isomorphic Transition in beta-pyrochlore KOs2O6
We investigate with a microscopic model anharmonic K-cation oscillation
observed by neutron experiments in beta-pyrochlore superconductor KOs2O6, which
also shows a mysterious first-order structural transition at Tp=7.5 K. We have
identified a set of microscopic model parameters that successfully reproduce
the observed temperature dependence and the superconducting transition
temperature. Considering changes in the parameters at Tp, we can explain
puzzling experimental results about electron-phonon coupling and neutron data.
Our analysis demonstrates that the first-order transition is multipolar
transition driven by the octupolar component of K-cation oscillations. The
octupole moment does not change the symmetry and is characteristic to
noncentrosymmetric K-cation potential.Comment: 5 pages, 4 figures, submitted to J. Phys. Soc. Jp
Prime Focus Spectrograph - Subaru's future -
The Prime Focus Spectrograph (PFS) of the Subaru Measurement of Images and
Redshifts (SuMIRe) project has been endorsed by Japanese community as one of
the main future instruments of the Subaru 8.2-meter telescope at Mauna Kea,
Hawaii. This optical/near-infrared multi-fiber spectrograph targets cosmology
with galaxy surveys, Galactic archaeology, and studies of galaxy/AGN evolution.
Taking advantage of Subaru's wide field of view, which is further extended with
the recently completed Wide Field Corrector, PFS will enable us to carry out
multi-fiber spectroscopy of 2400 targets within 1.3 degree diameter. A
microlens is attached at each fiber entrance for F-ratio transformation into a
larger one so that difficulties of spectrograph design are eased. Fibers are
accurately placed onto target positions by positioners, each of which consists
of two stages of piezo-electric rotary motors, through iterations by using
back-illuminated fiber position measurements with a wide-field metrology
camera. Fibers then carry light to a set of four identical fast-Schmidt
spectrographs with three color arms each: the wavelength ranges from 0.38
{\mu}m to 1.3 {\mu}m will be simultaneously observed with an average resolving
power of 3000. Before and during the era of extremely large telescopes, PFS
will provide the unique capability of obtaining spectra of 2400
cosmological/astrophysical targets simultaneously with an 8-10 meter class
telescope. The PFS collaboration, led by IPMU, consists of USP/LNA in Brazil,
Caltech/JPL, Princeton, & JHU in USA, LAM in France, ASIAA in Taiwan, and
NAOJ/Subaru.Comment: 13 pages, 11 figures, submitted to "Ground-based and Airborne
Instrumentation for Astronomy IV, Ian S. McLean, Suzanne K. Ramsay, Hideki
Takami, Editors, Proc. SPIE 8446 (2012)
Prelimbic and Infralimbic Prefrontal Cortex Interact during Fast Network Oscillations
Background: The medial prefrontal cortex has been implicated in a variety of cognitive and executive processes such as decision making and working memory. The medial prefrontal cortex of rodents consists of several areas including the prelimbic and infralimbic cortex that are thought to be involved in different aspects of cognitive performance. Despite the distinct roles in cognitive behavior that have been attributed to prelimbic and infralimbic cortex, little is known about neuronal network functioning of these areas, and whether these networks show any interaction during fast network oscillations. Methodology/Principal Findings: Here we show that fast network oscillations in rat infralimbic cortex slices occur at higher frequencies and with higher power than oscillations in prelimbic cortex. The difference in oscillation frequency disappeared when prelimbic and infralimbic cortex were disconnected. Conclusions/Significance: Our data indicate that neuronal networks of prelimbic and infralimbic cortex can sustain fast network oscillations independent of each other, but suggest that neuronal networks of prelimbic and infralimbic cortex ar
Evaluation of the Total Design Method in a survey of Japanese dentists
BACKGROUND: This study assessed the application of the Total Design Method (TDM) in a mail survey of Japanese dentists. The TDM was chosen because survey response rates in Japan are unacceptably low and the TDM had previously been used in a general population survey. METHODS: Four hundred and seventy eight dentist members of the Okayama Medical and Dental Practitioner's Association were surveyed. The nine-page, 27-item questionnaire covered dentist job satisfaction, physical practice, and dentist and patient characteristics. Respondents to the first mailing or the one-week follow-up postcard were defined as early responders; others who responded were late responders. Responder bias was assessed by examining age, gender and training. RESULTS: The overall response rate was 46.7% (223/478). The response rates by follow-up mailing were, 18% after the first mailing, 35.4% after the follow-up postcard, 42.3% after the second mailing, and 46.7% after the third mailing. Respondents did not differ from non-respondents in age or gender, nor were there differences between early and late responders. CONCLUSION: The application of TDM in this survey of Japanese dentists produced lower rates of response than expected from previous Japanese and US studies
SUBARU prime focus spectrograph: integration, testing and performance for the first spectrograph
The Prime Focus Spectrograph (PFS) of the Subaru Measurement of Images and
Redshifts (SuMIRe) project for Subaru telescope consists in four identical
spectrographs fed by 600 fibers each. Each spectrograph is composed by an
optical entrance unit that creates a collimated beam and distributes the light
to three channels, two visibles and one near infrared. This paper presents the
on-going effort for the tests & integration process for the first spectrograph
channel: we have developed a detailed Assembly Integration and Test (AIT) plan,
as well as the methods, detailed processes and I&T tools. We describe the tools
we designed to assemble the parts and to test the performance of the
spectrograph. We also report on the thermal acceptance tests we performed on
the first visible camera unit. We also report on and discuss the technical
difficulties that did appear during this integration phase. Finally, we detail
the important logistic process that is require to transport the components from
other country to Marseille
OsWRKY IIa Transcription Factors Modulate Rice Innate Immunity
WRKY transcription factors regulate diverse plant processes including responses to biotic stresses. Our previous studies indicate that OsWRKY62, an OsWRKY IIa subfamily member, functions as a negative regulator of the rice defense against Xanthomonas oryzae pv. oryzae. Here, we report that a large inverted repeat construct designed to knock down the expression of the four OsWRKY IIa subfamily members (OsWRKY62, OsWRKY28, OsWRKY71, and OsWRKY76) leads to overexpression of all four genes and disease resistance in some transgenic plants. These phenotypes are stably inherited as reflected by progeny analysis. A pathogenesis-related gene, PR10, is up-regulated in plants overexpressing the OsWRKY IIa genes. These results suggest that OsWRKY IIa proteins interact functionally to modulate plant innate immunity
Prime Focus Spectrograph (PFS) for the Subaru Telescope: Overview, recent progress, and future perspectives
PFS (Prime Focus Spectrograph), a next generation facility instrument on the
8.2-meter Subaru Telescope, is a very wide-field, massively multiplexed,
optical and near-infrared spectrograph. Exploiting the Subaru prime focus, 2394
reconfigurable fibers will be distributed over the 1.3 deg field of view. The
spectrograph has been designed with 3 arms of blue, red, and near-infrared
cameras to simultaneously observe spectra from 380nm to 1260nm in one exposure
at a resolution of ~1.6-2.7A. An international collaboration is developing this
instrument under the initiative of Kavli IPMU. The project is now going into
the construction phase aiming at undertaking system integration in 2017-2018
and subsequently carrying out engineering operations in 2018-2019. This article
gives an overview of the instrument, current project status and future paths
forward.Comment: 17 pages, 10 figures. Proceeding of SPIE Astronomical Telescopes and
Instrumentation 201
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