1,629 research outputs found
Jets and Jet Multiplicities in High Energy Photon-Nucleon Inetraction:
We discuss the theory of jet events in high-energy photon-proton interactions
using a model which gives a good description of the data available on total
inelastic cross sections up to =210 GeV. We show how to
calculate the jet cross sections and jet multiplicities and give predictions
for these quantities for energies appropriate for experiments at the HERA
collider and for very high energy cosmic ray observations.Comment: 12 pages + 4 figs, MAD/TH/92-8, submitted to Phys. Rev. D(Rapid
Communications), figs. available on request from [email protected]
Long-distance entanglement-based quantum key distribution over optical fiber
We report the first entanglement-based quantum key distribution (QKD) experiment over a 100-km optical fiber. We used superconducting single photon detectors based on NbN nanowires that provide high-speed single photon detection for the 1.5-µm telecom band, an efficient entangled photon pair source that consists of a fiber coupled periodically poled lithium niobate waveguide and ultra low loss filters, and planar lightwave circuit Mach-Zehnder interferometers (MZIs) with ultra stable operation. These characteristics enabled us to perform an entanglement-based QKD experiment over a 100-km optical fiber. In the experiment, which lasted approximately 8 hours, we successfully generated a 16 kbit sifted key with a quantum bit error rate of 6.9 % at a rate of 0.59 bits per second, from which we were able to distill a 3.9 kbit secure key
High-pressure study of X-ray diffuse scattering in ferroelectric perovskites
We present a high-pressure x-ray diffuse scattering study of the ABO
ferroelectric perovskites BaTiO_3 and KNbO_3. The well-known diffuse lines are
observed in all the phases studied. In KNbO_3, we show that the lines are
present up to 21.8 GPa, with constant width and a slightly decreasing
intensity. At variance, the intensity of the diffuse lines observed in the
cubic phase of BaTiO_3 linearly decreases to zero at GPa. These
results are discussed with respect to x-ray absorption measurements, which
leads to the conclusion that the diffuse lines are only observed when the B
atom is off the center of the oxygen tetrahedron. The role of such disorder on
the ferroelectric instability of perovskites is discussed.Comment: 4 pages, Accepted in PR
Megabits secure key rate quantum key distribution
Quantum cryptography (QC) can provide unconditional secure communication
between two authorized parties based on the basic principles of quantum
mechanics. However, imperfect practical conditions limit its transmission
distance and communication speed. Here we implemented the differential phase
shift (DPS) quantum key distribution (QKD) with up-conversion assisted hybrid
photon detector (HPD) and achieved 1.3 M bits per second secure key rate over a
10-km fiber, which is tolerant against the photon number splitting (PNS)
attack, general collective attacks on individual photons, and any other known
sequential unambiguous state discrimination (USD) attacks.Comment: 14 pages, 4 figure
Trends in health and health inequality during the Japanese economic stagnation: Implications for a healthy planet
Introduction: Human health and wellbeing may depend on economic growth, the implication being that policymakers need to choose between population health and the health of ecosystems. Over two decades of low economic growth, Japan's life expectancy grew. Here we assess the temporal changes of subjective health and health inequality during the long-term low economic growth period. Methods: Eight triennial cross-sectional nationally representative surveys in Japan over the period of economic stagnation from 1992 to 2013 were used (n = 625,262). Health is defined positively as wellbeing, and negatively as poor health, based on self-rated health. We used Slope and Relative Indices of Inequality to model inequalities in self-rated health based on household income. Temporal changes in health and health inequalities over time were examined separately for children/adolescents, working-age adults, young-old and old-old. Results: At the end of the period of economic stagnation (2013), compared to the beginning (1992), the overall prevalence of wellbeing declined slightly in all age groups. However, poor health was stable or declined in the young-old and old-old, respectively, and increased only in working-age adults (Prevalence ratio: 1.14, 95% CI 1.08, 1.20, <0.001). Over time, inequality in wellbeing and poor self-rated health were observed in adults but less consistently for children, but the inequalities did not widen in any age group between the start and end of the stagnation period. Conclusions: Although this study was a case study of one country, Japan, and inference to other countries cannot be made with certainty, the findings provide evidence that low economic growth over two decades did not inevitably translate to unfavourable population health. Japanese health inequalities according to income were stable during the study period. Therefore, this study highlighted the possibility that for high-income countries, low economic growth may be compatible with good population health
Relationship between production of acute-phase proteins and strength of inflammatory stimulation in rats
The relationship between intensity of inflammatory stimulation and production of α2-macroglobulin (α2M) and α1-acid glycoprotein (AAG) in rats was investigated. Sprague-Dawley rats were injected with turpentine oil at doses of 0.05, 0.2 or 0.4 mL/rat. Serum levels of α2M, interleukin (IL)-6 and cytokine-induced neutrophil chemoattractant-1 (CINC-1) were measured by enzyme-linked immunosorbent assay, and AAG was measured by single radial immunodiffusion. Peak serum levels of α2M and AAG in rats injected at 0.05 mL/rat were significantly lower than those at 0.2 or 0.4 mL/rat. However, no significant differences were observed for peak serum levels of these acute-phase proteins between 0.2 and 0.4 mL/rat. Furthermore, peak serum levels of IL-6 and CINC-1 in rats injected at 0.05 mL/rat were significantly lower than those at 0.2 or 0.4 mL/rat. Thus, the production of these acute-phase proteins has upper limits, even under increased strength of inflammatory stimulation in rats injected with turpentine oil
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