7,292 research outputs found
Three path interference using nuclear magnetic resonance: a test of the consistency of Born's rule
The Born rule is at the foundation of quantum mechanics and transforms our
classical way of understanding probabilities by predicting that interference
occurs between pairs of independent paths of a single object. One consequence
of the Born rule is that three way (or three paths) quantum interference does
not exist. In order to test the consistency of the Born rule, we examine
detection probabilities in three path intereference using an ensemble of
spin-1/2 quantum registers in liquid state nuclear magnetic resonance (LSNMR).
As a measure of the consistency, we evaluate the ratio of three way
interference to two way interference. Our experiment bounded the ratio to the
order of , and hence it is consistent with Born's rule.Comment: 11 pages, 4 figures; Improved presentation of figures 1 and 4,
changes made in section 2 to better describe the experiment, minor changes
throughout, and added several reference
Musical Robots For Children With ASD Using A Client-Server Architecture
Presented at the 22nd International Conference on Auditory Display (ICAD-2016)People with Autistic Spectrum Disorders (ASD) are known to have difficulty recognizing and expressing emotions, which affects their social integration. Leveraging the recent advances in interactive robot and music therapy approaches, and integrating both, we have designed musical robots that can facilitate social and emotional interactions of children with ASD. Robots communicate with children with ASD while detecting their emotional states and physical activities and then, make real-time sonification based on the interaction data. Given that we envision the use of multiple robots with children, we have adopted a client-server architecture. Each robot and sensing device plays a role as a terminal, while the sonification server processes all the data and generates harmonized sonification. After describing our goals for the use of sonification, we detail the system architecture and on-going research scenarios. We believe that the present paper offers a new perspective on the sonification application for assistive technologies
Quantum simulation costs for Suzuki-Trotter decomposition of quantum many-body lattice models
Quantum computers offer the potential to efficiently simulate the dynamics of
quantum systems, a task whose difficulty scales exponentially with system size
on classical devices. To assess the potential for near-term quantum computers
to simulate many-body systems we develop a formalism to straightforwardly
compute bounds on the number of Trotter steps needed to accurately simulate the
time evolution of fermionic lattice models based on the first-order commutator
scaling. We apply this formalism to two closely related many-body models
prominent in condensed matter physics, the Hubbard and t-J models. We find
that, while a naive comparison of the Trotter depth first seems to favor the
Hubbard model, careful consideration of the model parameters and the allowable
error for accurate simulation leads to a substantial advantage in favor of the
t-J model. These results and formalism set the stage for significant
improvements in quantum simulation costs.Comment: 20 pages, 10 figure
Reverberation Mapping of PG 0934+013 with the Southern African Large Telescope
We present the variability and time lag measurements of PG 0934+013 based on
a photometric and spectroscopic monitoring campaign over a two year period. We
obtained 46 epochs of data from the spectroscopic campaign, which was carried
out using the Southern African Large Telescope with 1 week cadence over
two sets of 4 month-long observing period, while we obtained 80 epochs of
\textit{B}-band imaging data using a few 1-m class telescopes. Due to the seven
month gap between the two observing periods, we separately measured the time
lags of broad emission lines including H, by comparing the emission line
light curve with the \textit{B}-band continuum light curve using the
cross-correlation function techniques. We determined the H lag,
days in the observed-frame based on
Year 2 data, while the time lag from Year 1 data was not reliably determined.
Using the rms spectrum of Year 2 data, we measured the \Hb\ line dispersion
\sigmaline = 668 44 \kms\ after correcting for the spectral resolution.
Adopting a virial factor f = 4.47 from Woo et al. 2015, we determined the black
hole mass M = \msun based on the
\Hb\ time lag and velocity.Comment: 13 pages, 10 figures, ApJ in pres
Real-time spatio-temporal coherence estimation for autonomous mode identification and invariance tracking
A general method of anomaly detection from time-correlated sensor data is disclosed. Multiple time-correlated signals are received. Their cross-signal behavior is compared against a fixed library of invariants. The library is constructed during a training process, which is itself data-driven using the same time-correlated signals. The method is applicable to a broad class of problems and is designed to respond to any departure from normal operation, including faults or events that lie outside the training envelope
Precession of Mercury’s Perihelion from Ranging to the MESSENGER Spacecraft
The perihelion of Mercury's orbit precesses due to perturbations from other solar system bodies, solar quadrupole moment (J [subscript 2]), and relativistic gravitational effects that are proportional to linear combinations of the parametrized post-Newtonian parameters β and γ. The orbits and masses of the solar system bodies are quite well known, and thus the uncertainty in recovering the precession rate of Mercury's perihelion is dominated by the uncertainties in the parameters J [subscript 2], β, and γ. Separating the effects due to these parameters is challenging since the secular precession rate has a linear dependence on each parameter. Here we use an analysis of radiometric range measurements to the MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft in orbit about Mercury to estimate the precession of Mercury's perihelion. We show that the MESSENGER ranging data allow us to measure not only the secular precession rate of Mercury's perihelion with substantially improved accuracy, but also the periodic perturbation in the argument of perihelion sensitive to β and γ. When combined with the γ estimate from a Shapiro delay experiment from the Cassini mission, we can decouple the effects due to β and J [subscript 2] and estimate both parameters, yielding (β -1)=(-2.7 ± 3.9) x 10[superscript -5] and J [subscript 2] = (2.25 ± 0.09) × 10[superscript −7]. We also estimate the total precession rate of Mercury's perihelion as 575.3100 ± 0.0015''/century and provide estimated contributions and uncertainties due to various perturbing effects
Applications of Fluorescent Quantum Dots for Reproductive Medicine and Disease Detection
Understanding the mechanisms associated with fertility and disease management in animals remains challenging. Continuing advances in nanotechnology provide new tools and alternative approaches for the investigation of these mechanisms. Fluorescent quantum dot nanoparticles, for example, have unique physicochemical properties, which allow for in vivo and in vitro imaging in various areas of life sciences. Traditional quantum dots contain heavy metal semiconductor cores, which have raised concern over their potential for toxicity. The majority of available quantum dots today prevent heavy metal release with additional chemical and polymer layers for safe water solubility. In this chapter, the most widely used quantum dots made of cadmium selenide, which possess great potential for real-time imaging in disease detection and reproductive medicine, are discussed
Puberty Timing and Markers of Cardiovascular Structure and Function at 25 Years:A Prospective Cohort Study
BACKGROUND: Whether earlier onset of puberty is associated with higher cardiovascular risk in early adulthood is not well understood. Our objective was to examine the association between puberty timing and markers of cardiovascular structure and function at age 25 years. METHODS: We conducted a prospective birth cohort study using data from the Avon Longitudinal Study of Parents and Children (ALSPAC). Participants were born between April 1, 1991, and December 31, 1992. Exposure of interest was age at peak height velocity (aPHV), an objective and validated growth-based measure of puberty onset. Outcome measures included cardiovascular structure and function at age 25 years: carotid intima-media thickness (CIMT), left ventricular mass index (LVMI) and relative wall thickness (RWT), pulse wave velocity (PWV) and systolic blood pressure (SBP). Multiple imputation was used to impute missing data on covariates and outcomes. Linear regression was used to examine the association between aPHV and each measure of cardiac structure and function, adjusting for maternal age, gestational age, household social class, maternal education, mother’s partner’s education, breastfeeding, parity, birthweight, maternal body mass index, maternal marital status, maternal prenatal smoking status and height and fat mass at age 9. All analyses were stratified by sex. RESULTS: A total of 2752–4571 participants were included in the imputed analyses. A 1-year older aPHV was not strongly associated with markers of cardiac structure and function in males and females at 25 years and most results spanned the null value. In adjusted analyses, a 1-year older aPHV was associated with 0.003 mm (95% confidence interval (CI) 0.00001, 0.006) and 0.0008 mm (95% CI − 0.002, 0.003) higher CIMT; 0.02 m/s (95% CI − 0.05, 0.09) and 0.02 m/s (95% CI − 0.04, 0.09) higher PWV; and 0.003 mmHg (95% CI − 0.60, 0.60) and 0.13 mmHg (95% CI − 0.44, 0.70) higher SBP, among males and females, respectively. A 1-year older aPHV was associated with − 0.55 g/m2.7 (95% CI − 0.03, − 1.08) and − 0.89 g/m^{2.7} (95% CI − 0.45, − 1.34) lower LVMI and − 0.001 (95% CI − 0.006, 0.002) and − 0.002 (95% CI − 0.006, 0.002) lower RWT among males and females. CONCLUSIONS: Earlier puberty is unlikely to have a major impact on pre-clinical cardiovascular risk in early adulthood
Salt restriction lowers blood pressure at rest and during exercise without altering peripheral hemodynamics in hypertensive individuals
Dietary salt restriction is a well-established approach to lower blood pressure and reduce cardiovascular disease risk in hypertensive individuals. However, little is currently known regarding the effects of salt restriction on central and peripheral hemodynamic responses to exercise in those with hypertension. Therefore, this study sought to determine the impact of salt restriction on the central and peripheral hemodynamic responses to static-intermittent handgrip (HG) and dynamic single-leg knee extension (KE) exercise in individuals with hypertension. Twenty-two subjects (14 men and 8 women, 51 ± 10 yr, 173 ± 11 cm, 99 ± 23 kg) forewent their antihypertensive medication use for at least 2 wk before embarking on a 5-day liberal salt (LS: 200 mmol/day) diet followed by a 5-day restricted salt (RS: 10 mmol/day) diet. Subjects were studied at rest and during static intermittent HG exercise at 15, 30, and 45% of maximal voluntary contraction and KE exercise at 40, 60, and 80% of maximum KE work rate. Salt restriction lowered resting systolic blood pressure (supine: −12 ± 12 mmHg, seated: −17 ± 12 mmHg) and diastolic blood pressure (supine: −3 ± 9 mmHg, seated: −5 ± 7 mmHg, P \u3c 0.05). Despite an ~8 mmHg lower mean arterial blood pressure during both HG and KE exercise following salt restriction, neither central nor peripheral hemodynamics were altered. Therefore, salt restriction can lower blood pressure during exercise in subjects with hypertension, reducing the risk of cardiovascular events, without impacting central and peripheral hemodynamics during either arm or leg exercise
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