We propose to search for light U(1) dark photons, A^{'}, produced via kinetically mixing with ordinary photons via the Compton-like process, γe^{-}→A^{'}e^{-}, in a nuclear reactor and detected by ...their interactions with the material in the active volumes of reactor neutrino experiments. We derive 95% confidence-level upper limits on ε, the A^{'}-γ mixing parameter, ε, for dark-photon masses below 1 MeV of ε<1.3×10^{-5} and ε<2.1×10^{-5}, from NEOS and TEXONO experimental data, respectively. This study demonstrates the applicability of nuclear reactors as potential sources of intense fluxes of low-mass dark photons.
Asymptomatic hemorrhagic transformation (HT) is not associated with immediate deterioration of patients with acute ischemic stroke. However, it is unclear whether it is clinically innocuous with ...respect to long-term outcome. The aim of this study was to determine the impact of asymptomatic HT on 3-month outcome.
A consecutive series of 1,618 patients, hospitalized between January 2004 and August 2007 for ischemic stroke within 7 days from symptom onset were identified in a prospective stroke registry database. Those who had no evidence of acute cerebral ischemia on diffusion-weighted MRI, who did not undergo T2-weighted gradient echo MRI, whose modified Rankin Scale (mRS) score at 3 months after stroke onset was not available, or who had symptomatic HT were excluded. The odds ratio (OR) of asymptomatic HT was calculated for the full distribution of mRS score and adjusted for variables with p < 0.25 with respect to their associations with asymptomatic HT or functional outcome.
Of 1,412 patients eligible for the study, 100 (7.1%) had asymptomatic HT. Patients who experienced asymptomatic HT were more likely to have cardioembolic stroke, to receive thrombolytic therapy, to receive anticoagulation with heparin, and to have a higher initial NIH Stroke Scale score. The crude and adjusted ORs of asymptomatic HT for an increment of mRS score at 3 months were 2.94 (95% confidence interval 2.05-4.24) and 1.90 (1.27-2.82), respectively.
Our study shows that the odds of a worse outcome are increased by a factor of 2 in patients with asymptomatic HT compared with those without HT after acute ischemic stroke.
Primary cosmic-ray elemental spectra have been measured with the balloon-borne Cosmic Ray Energetics And Mass (CREAM) experiment since 2004. The third CREAM payload (CREAM-III) flew for 29 days ...during the 2007-2008 Antarctic season. Energies of incident particles above 1 TeV are measured with a calorimeter. Individual elements are clearly separated with a charge resolution of ∼0.12 e (in charge units) and ∼0.14 e for protons and helium nuclei, respectively, using two layers of silicon charge detectors. The measured proton and helium energy spectra at the top of the atmosphere are harder than other existing measurements at a few tens of GeV. The relative abundance of protons to helium nuclei is 9.53 0.03 for the range of 1 TeV/n to 63 TeV/n. This ratio is considerably smaller than other measurements at a few tens of GeV/n. The spectra become softer above ∼20 TeV. However, our statistical uncertainties are large at these energies and more data are needed.
Efficient interfaces between photons and quantum emitters form the basis for quantum networks and enable optical nonlinearities at the single-photon level. We demonstrate an integrated platform for ...scalable quantum nanophotonics based on silicon-vacancy (SiV) color centers coupled to diamond nanodevices. By placing SiV centers inside diamond photonic crystal cavities, we realize a quantum-optical switch controlled by a single color center. We control the switch using SiV metastable states and observe optical switching at the singlephoton level. Raman transitions are used to realize a single-photon source with a tunable frequency and bandwidth in a diamond waveguide. By measuring intensity correlations of indistinguishable Raman photons emitted into a single waveguide, we observe a quantum interference effect resulting from the superradiant emission of two entangled SiV centers.
In the quest to increase the critical temperature Tc of cuprate superconductors, it is essential to identify the factors that limit the strength of superconductivity. The upper critical field Hc2 is ...a fundamental measure of that strength, yet there is no agreement on its magnitude and doping dependence in cuprate superconductors. Here we show that the thermal conductivity can be used to directly detect Hc2 in the cuprates YBa2Cu3Oy, YBa2Cu4O8 and Tl2Ba2CuO6+δ, allowing us to map out Hc2 across the doping phase diagram. It exhibits two peaks, each located at a critical point where the Fermi surface of YBa2Cu3Oy is known to undergo a transformation. Below the higher critical point, the condensation energy, obtained directly from Hc2, suffers a sudden 20-fold collapse. This reveals that phase competition-associated with Fermi-surface reconstruction and charge-density-wave order-is a key limiting factor in the superconductivity of cuprates.
Abstract ABO-incompatible (ABOi) adult living donor liver transplantation (ALDLT) is a feasible therapeutic option for countries with a scarcity of deceased donors. This report presents our initial ...experiences in ABOi ALDLT in 10 patients between December 2008 and September 2009. The mean age of recipients was 48.5 ± 5.7 years (range, 40–54 years). The mean Model for End-stage Liver-Disease score was 13.9 ± 4.0 (range, 9–22). All patients were administered preoperative rituximab once and plasma exchanges according to the hemagglutinin titer. The spleen was preserved in all cases. For local infusion therapy, hepatic arterial infusion was performed in 9 patients and portal vein infusion in 1 subject. The 10 patients experienced no in-hospital mortality. At a mean follow-up period of 31.8 ± 2.9 months (range, 4.1–34.9 months), 1 patient has died (postoperative month 4 due to sepsis following a biliary stricture. The 3-month patient and graft survivals were 100%, and 1- and 2-year survivals, 90.0%. There was no episode of antibody-mediated rejection. The promising results of our initial experience may have been due to the use of preoperative rituximab and the good preoperative conditions of the patients.
Volatile organic compounds (VOCs) are reported to cause adverse effects on pulmonary function in occupationally exposed workers. However, evidence is lacking on the effect in the general population. ...We hypothesised that VOCs impair pulmonary function through enhancing oxidative stress, especially in the elderly population. A longitudinal panel study of 154 elderly people was performed in South Korea. Repeated spirometric tests were performed up to eight times on different days for each subject. We also measured urinary concentrations of metabolites of the VOC and markers of oxidative stress (malondialdehyde and 8-oxo-2'-deoxyguanosine) on the same day of spirometric tests. A mixed linear regression model was used to evaluate the association among the VOC metabolites, oxidative stress markers and spirometric tests. We found that the urinary levels of hippuric acid and methylhippuric acid, which are metabolites of toluene and xylene, respectively, were significantly associated with reduction of forced expiratory volume in 1 s (FEV₁), FEV₁/forced vital capacity (FVC), and forced expiratory flow at 25-75% of FVC. We also found significant associations between the metabolites of VOCs and the markers of oxidative stress. In addition, the oxidative stress markers were associated with pulmonary function parameters. This study suggests that exposure to toluene and xylene exert a harmful effect on pulmonary function by exacerbating oxidative stress in elderly people.
We present a background model for dark matter searches using an array of NaI(Tl) crystals in the COSINE-100 experiment that is located in the Yangyang underground laboratory. The model includes ...background contributions from both internal and external sources, including cosmogenic radionuclides and surface
210
Pb contamination. To build the model in the low energy region, with a threshold of 1 keV, we used a depth profile of
210
Pb contamination in the surface of the NaI(Tl) crystals determined in a comparison between measured and simulated spectra. We also considered the effect of the energy scale errors propagated from the statistical uncertainties and the nonlinear detector response at low energies. The 1.7 years COSINE-100 data taken between October 21, 2016 and July 18, 2018 were used for this analysis. Our Monte Carlo simulation provides a non-Gaussian peak around 50 keV originating from beta decays of bulk
210
Pb in a good agreement with the measured background. This model estimates that the activities of bulk
210
Pb and
3
H are dominating the background rate that amounts to an average level of
2.85
±
0.15
counts/day/keV/kg in the energy region of (1–6) keV, using COSINE-100 data with a total exposure of 97.7 kg
·
years.
PDF
