2,110 research outputs found
Experimental demonstration of four-party quantum secret sharing
Secret sharing is a multiparty cryptographic task in which some secret
information is splitted into several pieces which are distributed among the
participants such that only an authorized set of participants can reconstruct
the original secret. Similar to quantum key distribution, in quantum secret
sharing, the secrecy of the shared information relies not on computational
assumptions, but on laws of quantum physics. Here, we present an experimental
demonstration of four-party quantum secret sharing via the resource of
four-photon entanglement
Reduction of Benzylidene Dibenzo[ a, d ]cycloheptenes: Over-Reduction of Antiaromatic Dianions to Aromatic Tetraanions
The antiaromaticity of a series of dianions of p-substituted benzylidene dibenzo[a,d]cycloheptenes was examined through calculated measures of antiaromaticity. The nucleus-independent chemical shifts (NICS) and magnetic susceptibility exaltation both showed substantial antiaromatic character in the benzannulated tropylium anion. When the antiaromaticity was normalized for the area of the ring, these tropylium anions were shown to be among the most antiaromatic anions in the chemical literature. Attempts to make the dianion through reduction with lithium or potassium gave the tetraanion as the only species observable in the (1)H NMR spectrum. Quench of the reaction mixture with trimethylsilyl chloride or D(2)O confirmed the presence of the tetraanion, but only as a small portion of the reaction mixture, with the major product being unreacted starting material. The failure to observe starting material was attributed to similarities in the structures of the starting material and anion radical (first reduction), allowing rapid electron transfer between them. The inability to see the dianion (second reduction) could be the result of the very small HOMO-LUMO gap anticipated for highly antiaromatic species, which would allow access to diradical species. The magnitude of the HOMO-LUMO gap was determined by the difference between the HOMO and LUMO energies from geometry optimization and the lowest energy transition from TD-DFT calculations. The HOMO-LUMO gap for the benzylidene dibenzocycloheptatriene dianions was shown to be much smaller than the HOMO-LUMO gap of species for which (1)H NMR spectra had been observed
Natural disaster preparation and response: a guide for state housing authorities
A natural disaster is a rapid onset event that threatens or causes death, injury or damage to property or the environment, requiring a coordinated multi-agency and community response. The most costly and significant impacts of natural disasters and other environmental emergencies are on buildings. Damage or total loss of residential dwellings and social infrastructure especially accentuate hardship, homelessness, displacement and psychological trauma. For this reason, State Housing Authorities (SHAs) are among the key stakeholders with significant roles in disaster management. The overall aim of the project is to provide guidance for SHAs and to assist them prepare for and respond to natural disasters and other environmental emergencies
Quantification of Plasma and Urine Thymidine and 2'-Deoxyuridine by LC-MS/MS for the Pharmacodynamic Evaluation of Erythrocyte Encapsulated Thymidine Phosphorylase in Patients with Mitochondrial Neurogastrointestinal Encephalomyopathy.
Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is an ultra-rare disorder caused by mutations in TYMP, leading to a deficiency in thymidine phosphorylase and a subsequent systemic accumulation of thymidine and 2'-deoxyuridine. Erythrocyte-encapsulated thymidine phosphorylase (EE-TP) is under clinical development as an enzyme replacement therapy for MNGIE. Bioanalytical methods were developed according to regulatory guidelines for the quantification of thymidine and 2'-deoxyuridine in plasma and urine using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for supporting the pharmacodynamic evaluation of EE-TP. Samples were deproteinized with 5% perchloric acid (v/v) and the supernatants analyzed using a Hypercarb column (30 × 2.1 mm, 3 µm), with mobile phases of 0.1% formic acid in methanol and 0.1% formic acid in deionized water. Detection was conducted using an ion-spray interface running in positive mode. Isotopically labelled thymidine and 2'-deoxyuridine were used as internal standards. Calibration curves for both metabolites showed linearity (r > 0.99) in the concentration ranges of 10-10,000 ng/mL for plasma, and 1-50 µg/mL for urine, with method analytical performances within the acceptable criteria for quality control samples. The plasma method was successfully applied to the diagnosis of two patients with MNGIE and the quantification of plasma metabolites in three patients treated with EE-TP
Kinetics of Surface Enrichment: A Molecular Dynamics Study
We use molecular dynamics (MD) to study the kinetics of surface enrichment
(SE) in a stable homogeneous mixture (AB), placed in contact with a surface
which preferentially attracts A. The SE profiles show a characteristic
double-exponential behavior with two length scales: \xi_-, which rapidly
saturates to its equilibrium value, and \xi_+, which diverges as a power-law
with time (\xi_+ \sim t^\theta). We find that hydrodynamic effects result in a
crossover of the growth exponent from \theta \simeq 0.5 to \theta \simeq 1.0.
There is also a corresponding crossover in the growth dynamics of the SE-layer
thickness.Comment: 20 pages, 6 figures, Published in J. Chem. Phys. (Research
Highlights
Single particle multipole expansions from Micromagnetic Tomography
Micromagnetic tomography aims at reconstructing large numbers of individual
magnetizations of magnetic particles from combining high-resolution magnetic
scanning techniques with micro X-ray computed tomography (microCT). Previous
work demonstrated that dipole moments can be robustly inferred, and
mathematical analysis showed that the potential field of each particle is
uniquely determined. Here, we describe a mathematical procedure to recover
higher orders of the magnetic potential of the individual magnetic particles in
terms of their spherical harmonic expansions (SHE). We test this approach on
data from scanning superconducting quantum interference device microscopy and
microCT of a reference sample. For particles with high signal-to-noise ratio of
the magnetic scan we demonstrate that SHE up to order can be robustly
recovered. This additional level of detail restricts the possible internal
magnetization structures of the particles and provides valuable rock magnetic
information with respect to their stability and reliability as paleomagnetic
remanence carriers. Micromagnetic tomography therefore enables a new approach
for detailed rock magnetic studies on large ensembles of individual particles.Comment: 21 pages, 4 Figures, 3 Tables. For Supplemental Material see
"Ancillary files" in this arxiv websit
Trends in absolute socioeconomic inequalities in mortality in Sweden and New Zealand. A 20-year gender perspective
BACKGROUND: Both trends in socioeconomic inequalities in mortality, and cross-country comparisons, may give more information about the causes of health inequalities. We analysed trends in socioeconomic differentials by mortality from early 1980s to late 1990s, comparing Sweden with New Zealand. METHODS: The New Zealand Census Mortality Study (NZCMS) consisting of over 2 million individuals and the Swedish Survey of Living Conditions (ULF) comprising over 100, 000 individuals were used for analyses. Education and household income were used as measures of socioeconomic position (SEP). The slope index of inequality (SII) was calculated to estimate absolute inequalities in mortality. Analyses were based on 3–5 year follow-up and limited to individuals aged 25–77 years. Age standardised mortality rates were calculated using the European population standard. RESULTS: Absolute inequalities in mortality on average over the 1980s and 1990s for both men and women by education were similar in Sweden and New Zealand, but by income were greater in Sweden. Comparing trends in absolute inequalities over the 1980s and 1990s, men's absolute inequalities by education decreased by 66% in Sweden and by 17% in New Zealand (p for trend <0.01 in both countries). Women's absolute inequalities by education decreased by 19% in Sweden (p = 0.03) and by 8% in New Zealand (p = 0.53). Men's absolute inequalities by income decreased by 51% in Sweden (p for trend = 0.06), but increased by 16% in New Zealand (p = 0.13). Women's absolute inequalities by income increased in both countries: 12% in Sweden (p = 0.03) and 21% in New Zealand (p = 0.04). CONCLUSION: Trends in socioeconomic inequalities in mortality were clearly most favourable for men in Sweden. Trends also seemed to be more favourable for men than women in New Zealand. Assuming the trends in male inequalities in Sweden were not a statistical chance finding, it is not clear what the substantive reason(s) was for the pronounced decrease. Further gender comparisons are required
X-Ray Synchrotron White Beam Excitation of Auger Electrons
Auger electron spectra have been measured at the Cornell High Energy Synchrotron Source (CHESS), using the full white beam x-ray spectrum as the excitation source. Ordinary Auger spectra obtained in the laboratory with an electron beam source must employ derivative techniques to distinguish the Auger structures from the large background due to the excitation beam. The synchrotron white beam eliminates this source of background and produces signal rates as high as 107 cps. Superior signal-to-background ratios are found for Auger peaks above a few hundred eV, and count rates are large enough to suggest microprobe applications. X-ray induced Auger satellite peaks were observed with intensities much greater than the electron-induced counterpart; this anomaly is not completely understood
Relationship between Lake Stages and Local Ground-water Levels at Horseshoe Lake, Alexander County, Illinois
published or submitted for publicationis peer reviewedOpe
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