726 research outputs found
Quantum Computer Using Coupled Quantum Dot Molecules
We propose a method for implementation of a quantum computer using artificial
molecules. The artificial molecule consists of two coupled quantum dots stacked
along z direction and one single electron. One-qubit and two-qubit gates are
constructed by one molecule and two coupled molecules, respectively.The ground
state and the first excited state of the molecule are used to encode the |0>
and |1> states of a qubit. The qubit is manipulated by a resonant
electromagnetic wave that is applied directly to the qubit through a microstrip
line. The coupling between two qubits in a quantum controlled NOT gate is
switched on (off) by floating (grounding) the metal film electrodes. We study
the operations of the gates by using a box-shaped quantum dot model and
numerically solving a time-dependent Schridinger equation, and demonstrate that
the quantum gates can perform the quantum computation. The operating speed of
the gates is about one operation per 4ps. The reading operation of the output
of the quantum computer can be performed by detecting the polarization of the
qubits.Comment: 18 pages, 7 figures, submitted to Jpn. J. Appl. Phys, please send
your e-mail to Nan-Jian Wu <[email protected]
Recombination kinetics of a dense electron-hole plasma in strontium titanate
We investigated the nanosecond-scale time decay of the blue-green light
emitted by nominally pure SrTiO following the absorption of an intense
picosecond laser pulse generating a high density of electron-hole pairs. Two
independent components are identified in the fluorescence signal that show a
different dynamics with varying excitation intensity, and which can be
respectively modeled as a bimolecular and unimolecolar process. An
interpretation of the observed recombination kinetics in terms of interacting
electron and hole polarons is proposed
Uncertainty Orientation: A Theory of Self-Regulation Within and Across Cultures as Related to Cognition
Erich Fromm once said âthe quest for certainty blocks the search for meaning. Uncertainty is the very condition to impel man to unfold his powers.â For some, this quote is unmistakably true, impelling them to great discoveries of nature and the mind. For others, uncertainty is the very essence of confusion and ambiguity, offering nothing more than reason to retreat to more predictable and certain times. In this chapter, we explore the theory of uncertainty orientation as related to cognition and cognitive processes, including research that was conducted in Canada, Japan, and China. First, we discuss the characteristic uncertainty selfregulation styles that distinguish uncertainty-oriented individuals from certainty-oriented individuals. Next, we discuss the uncertainty orientation framework which integrates oneâs uncertainty self-regulation style, the uncertainty present in the situation, and oneâs characteristic motivations (e.g., achievement motivations) to predict performance outcomes in the related motivation domain. After discussing these basic tenants of our framework, we examine some of the cross-cultural research that has directly tested the predictions of the theory of uncertainty orientation. Concluding, we contrast our conceptualization of culture with how culture is commonly conceived in cross-cultural research
Photogenerated Carriers in SrTiO3 Probed by Mid-Infrared Absorption
Infrared absorption spectra of SrTiO have been measured under
above-band-gap photoexcitations to study the properties of photogenerated
carriers, which should play important roles in previously reported photoinduced
phenomena in SrTiO. A broad absorption band appears over the entire
mid-infrared region under photoexcitation. Detailed energy, temperature, and
excitation power dependences of the photoinduced absorption are reported. This
photo-induced absorption is attributed to the intragap excitations of the
photogenerated carriers. The data show the existence of a high density of
in-gap states for the photocarriers, which extends over a wide energy range
starting from the conduction and valence band edges.Comment: 5 pages, 5 figures, submitted to J. Phys. Soc. Jp
Optically tuned dimensionality crossover in photocarrier-doped SrTiO: onset of weak localization
We report magnetotransport properties of photogenerated electrons in undoped
SrTiO single crystals under ultraviolet illumination down to 2 K. By tuning
the light intensity, the steady state carrier density can be controlled, while
tuning the wavelength controls the effective electronic thickness by modulating
the optical penetration depth. At short wavelengths, when the sheet conductance
is close to the two-dimensional Mott minimum conductivity we have observed
critical behavior characteristic of weak localization. Negative
magnetoresistance at low magnetic field is highly anisotropic, indicating
quasi-two-dimensional electronic transport. The high mobility of photogenerated
electrons in SrTiO allows continuous tuning of the effective electronic
dimensionality by photoexcitation.Comment: 7 pages, 7 figure
Willingness to pay for municipality hospital services in rural Japan: a contingent valuation study
<p>Abstract</p> <p>Background</p> <p>The Japanese healthcare system has undergone reforms to address the struggles that municipality hospitals face. Reform guidelines clearly define criteria for administrative improvement. However, criteria to evaluate the demand for healthcare provisions in rural Japan, including the needs of rural residents for municipality hospitals in particular have not been specified. The purpose of this paper is to measure residents' willingness to pay (WTP) for municipality hospital services using the contingent valuation method, and to evaluate municipality hospital valuation on the basis of WTP. K town, located in the Hokkaido prefecture of Japan, was selected as the location for this study. Participants were recruited by a town hall healthcare administrator, hospital and clinic staff, and a local dentist. Participants were asked what amount they would be willing to pay as taxes to continue accessing the services of the municipality hospital for one year by using open-ended questions in face-to-face interviews.</p> <p>Findings</p> <p>Forty-eight residents were initially recruited, and 40 participants were selected for the study (response rate 83%). As compared to K town's population, this data slanted toward the elderly, although there was no significant difference in frequency among the characteristics. The median WTP was estimated at 39,484 yen (308.95-615.96). Logistic regression revealed no significant factors affecting WTP.</p> <p>Conclusions</p> <p>If the total amount of residents' WTP for the municipality hospital were to be estimated by this result, it would calculate with 129,586,000 yen ($1,439,844). This is approximately equal to the amount of money to be transferred from the general account of the government of K town, more than one-half of the town tax of K town, and about two-fold in comparison to Japan as a whole. This showed that K town's residents placed a high valuation on the municipality hospital, which nearly equalled the amount that the K town government provided to the municipality hospital to cover its annual deficit. K town residents had come to expect not only general clinical practice, but also emergency medical services and night practice provided by their own town's municipality hospital. WTP can be used as a measure of hospital evaluation because it reflects the importance of the hospital to the residents in its region.</p
Virus Recognition by Toll-7 Activates Antiviral Autophagy in Drosophila
SummaryInnate immunity is highly conserved and relies on pattern recognition receptors (PRRs) such as Toll-like receptors (identified through their homology to Drosophila Toll) for pathogen recognition. Although Drosophila Toll is vital for immune recognition and defense, roles for the other eight Drosophila Tolls in immunity have remained elusive. Here we have shown that Toll-7 is a PRR both in vitro and in adult flies; loss of Toll-7 led to increased vesicular stomatitis virus (VSV) replication and mortality. Toll-7, along with additional uncharacterized Drosophila Tolls, was transcriptionally induced by VSV infection. Furthermore, Toll-7 interacted with VSV at the plasma membrane and induced antiviral autophagy independently of the canonical Toll signaling pathway. These data uncover an evolutionarily conserved role for a second Drosophila Toll receptor that links viral recognition to autophagy and defense and suggest that other Drosophila Tolls may restrict specific as yet untested pathogens, perhaps via noncanonical signaling pathways
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