312 research outputs found
The Association Between Dental Coverage and Self-reported Health in Older Adults jGPHA
Background: For the older population of the United States, lack of dental insurance coverage is a substantial health problem. The purpose of the present study was to examine the longitudinal relationship between dental coverage and self-reported health among older adults.
Methods: The Health and Retirement Study (HRS), a nationally representative biennial cohort study of community-dwelling individuals, includes 19,595 adults (aged 50 and older) living in the United States. For the 2010, 2012, and 2014 waves, the independent variable of dental coverage and the outcome of self-reported health were examined.
Results: At each time point, dental coverage for older adults had a positive association with self-reported health (parameter estimate, β=0.340, standard error (SE)=0.039, p\u3c0.0001), controlling for sociodemographic variables of age, sex, race/ethnicity, education, and the status of edentulism. There were no significant longitudinal effects for dental coverage associated with selfreported health.
Conclusions: At each time point, the results show a positive association between having dental coverage and better self-reported health of older adults. This is relevant, because, in the United States, there is an increasing population of older people
Comparison of Reproductive Performance of Crossbred Ewes Bred for Either Fall or Spring Lambing at Two Different Locations: Progress Report
The objective of the current study was to measure the performance of crossbred ewes lambing in the fall compared to similar ewes lambing in the spring at two different locations
Mapping coherence in measurement via full quantum tomography of a hybrid optical detector
Quantum states and measurements exhibit wave-like --- continuous, or
particle-like --- discrete, character. Hybrid discrete-continuous photonic
systems are key to investigating fundamental quantum phenomena, generating
superpositions of macroscopic states, and form essential resources for
quantum-enhanced applications, e.g. entanglement distillation and quantum
computation, as well as highly efficient optical telecommunications. Realizing
the full potential of these hybrid systems requires quantum-optical
measurements sensitive to complementary observables such as field quadrature
amplitude and photon number. However, a thorough understanding of the practical
performance of an optical detector interpolating between these two regions is
absent. Here, we report the implementation of full quantum detector tomography,
enabling the characterization of the simultaneous wave and photon-number
sensitivities of quantum-optical detectors. This yields the largest
parametrization to-date in quantum tomography experiments, requiring the
development of novel theoretical tools. Our results reveal the role of
coherence in quantum measurements and demonstrate the tunability of hybrid
quantum-optical detectors.Comment: 7 pages, 3 figure
Higher-order binding corrections to the Lamb shift of 2P states
We present an improved calculation of higher-order corrections to the
one-loop self energy of 2P states in hydrogen-like systems with small nuclear
charge Z. The method is based on a division of the integration with respect to
the photon energy into a high- and a low-energy part. The high-energy part is
calculated by an expansion of the electron propagator in powers of the Coulomb
field. The low-energy part is simplified by the application of a
Foldy-Wouthuysen transformation. This transformation leads to a clear
separation of the leading contribution from the relativistic corrections and
removes higher order terms. The method is applied to the 2P_{1/2} and 2P_{3/2}
states in atomic hydrogen. The results lead to new theoretical values for the
Lamb shifts and the fine structure splitting.Comment: 18 pages, LaTeX. In comparison to the journal version, it contains an
added note (2000) which reflects the current status of Lamb shift
calculation
Proton Pump Inhibitors in the Management of Tachypnoea following Panproctocolectomy: A Case of High Output Ileostomy
High output ileostomies are important complications of stoma formation following bowel surgery. Adequate management of such stomas might prevent severe morbidity and mortality when this potentially fatal complication develops. In this case report, we describe a female patient with a recent ileostomy formation following panproctocolectomy for ulcerative colitis who presented with progressively increasing shortness of breath. The patient was found to have a hypochloraemic metabolic acidosis on arterial blood gases. She rapidly improved with adequate sodium and fluid replacement and with the use of a course of proton pump inhibitors. This case highlights the importance of recognising high output ileostomies early and important management issues in their regard
Rank-based model selection for multiple ions quantum tomography
The statistical analysis of measurement data has become a key component of
many quantum engineering experiments. As standard full state tomography becomes
unfeasible for large dimensional quantum systems, one needs to exploit prior
information and the "sparsity" properties of the experimental state in order to
reduce the dimensionality of the estimation problem. In this paper we propose
model selection as a general principle for finding the simplest, or most
parsimonious explanation of the data, by fitting different models and choosing
the estimator with the best trade-off between likelihood fit and model
complexity. We apply two well established model selection methods -- the Akaike
information criterion (AIC) and the Bayesian information criterion (BIC) -- to
models consising of states of fixed rank and datasets such as are currently
produced in multiple ions experiments. We test the performance of AIC and BIC
on randomly chosen low rank states of 4 ions, and study the dependence of the
selected rank with the number of measurement repetitions for one ion states. We
then apply the methods to real data from a 4 ions experiment aimed at creating
a Smolin state of rank 4. The two methods indicate that the optimal model for
describing the data lies between ranks 6 and 9, and the Pearson test
is applied to validate this conclusion. Additionally we find that the mean
square error of the maximum likelihood estimator for pure states is close to
that of the optimal over all possible measurements.Comment: 24 pages, 6 figures, 3 table
Measuring measurement
Measurement connects the world of quantum phenomena to the world of classical
events. It plays both a passive role, observing quantum systems, and an active
one, preparing quantum states and controlling them. Surprisingly - in the light
of the central status of measurement in quantum mechanics - there is no general
recipe for designing a detector that measures a given observable. Compounding
this, the characterization of existing detectors is typically based on partial
calibrations or elaborate models. Thus, experimental specification (i.e.
tomography) of a detector is of fundamental and practical importance. Here, we
present the realization of quantum detector tomography: we identify the optimal
positive-operator-valued measure describing the detector, with no ancillary
assumptions. This result completes the triad, state, process, and detector
tomography, required to fully specify an experiment. We characterize an
avalanche photodiode and a photon number resolving detector capable of
detecting up to eight photons. This creates a new set of tools for accurately
detecting and preparing non-classical light.Comment: 6 pages, 4 figures,see video abstract at
http://www.quantiki.org/video_abstracts/0807244
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