92 research outputs found
No Changes in Appetite Stimulating Hormones Following Swimming and Cycling Exercise Interventions
Swimming is a favorable and ideal modality of exercise for individuals with obesity and arthritis as it encompasses a minimal weight-bearing stress and a reduced heat load. However, the available evidence indicates that regular swimming may not be effective in reducing body weight and body fatness. A current hypothesis is that exercise in cold water somehow stimulates appetite. PURPOSE: We determined the effect of swimming exercise training on fasting concentrations of ghrelin, insulin, leptin, and peptide YY in obese individuals with osteoarthritis. Cycling training was included as a non-weight bearing land-based comparison group. METHODS: Thirty-nine obese participants with osteoarthritis (age=59±1 years, BMI=33±1 kg/m2) were randomly assigned to 12 weeks of supervised swimming training (N=19) or cycling training (N=20). In the initial few weeks, participants exercised for 20-30 minutes/day, 3 days/week, at an exercise intensity of 40-50% of heart rate reserve (HRR). Subsequently, the intensity and duration of exercise were progressively increased to 40-45 minutes/day, 3 days/week, at an intensity of 60-70% of HRR. Fasting blood samples were analyzed for ghrelin, insulin, leptin, and peptide YY concentrations using ELISAs. RESULTS: There were no group differences in body weight, BMI, or appetite stimulating hormones prior to the exercise interventions. Fasting plasma concentrations of ghrelin (37±8 vs. 42±11 pg/ml), insulin (1,176±424 vs. 1,179±442 pg/ml), leptin (20,200±2,891 vs. 16,617±2,734 pg/ml), and peptide YY (51±6 vs. 54±7 pg/ml) did not change with the swimming exercise intervention (all p\u3e0.05). Similarly, cycling exercise had no effect on ghrelin (36±10 vs. 44±8 pg/ml), insulin (978±321 vs. 964±311 pg/ml), leptin (29,261±5,438 vs. 26,308±4,771 pg/ml), or peptide YY (58±15 vs. 63±16 pg/ml) concentrations (all p\u3e0.05). CONCLUSION: Our present results indicate that fasting levels of appetite stimulating hormones did not change with 12 weeks of swimming exercise intervention in obese participants with osteoarthritis and that there were no group differences in changes in these hormones between swimming and cycling exercise interventions
A Design and Analytic Strategy for Monitoring Disease Positivity and Case Characteristics in Accessible Closed Populations
We propose a monitoring strategy for efficient and robust estimation of
disease prevalence and case numbers within closed and enumerated populations
such as schools, workplaces, or retirement communities. The proposed design
relies largely on voluntary testing, notoriously biased (e.g., in the case of
COVID-19) due to non-representative sampling. The approach yields unbiased and
comparatively precise estimates with no assumptions about factors underlying
selection of individuals for voluntary testing, building on the strength of
what can be a small random sampling component. This component unlocks a
previously proposed "anchor stream" estimator, a well-calibrated alternative to
classical capture-recapture (CRC) estimators based on two data streams. We show
here that this estimator is equivalent to a direct standardization based on
"capture", i.e., selection (or not) by the voluntary testing program, made
possible by means of a key parameter identified by design. This equivalency
simultaneously allows for novel two-stream CRC-like estimation of general means
(e.g., of continuous variables such as antibody levels or biomarkers). For
inference, we propose adaptations of a Bayesian credible interval when
estimating case counts and bootstrapping when estimating means of continuous
variables. We use simulations to demonstrate significant precision benefits
relative to random sampling alone
Enhanced Inference for Finite Population Sampling-Based Prevalence Estimation with Misclassification Errors
Epidemiologic screening programs often make use of tests with small, but
non-zero probabilities of misdiagnosis. In this article, we assume the target
population is finite with a fixed number of true cases, and that we apply an
imperfect test with known sensitivity and specificity to a sample of
individuals from the population. In this setting, we propose an enhanced
inferential approach for use in conjunction with sampling-based bias-corrected
prevalence estimation. While ignoring the finite nature of the population can
yield markedly conservative estimates, direct application of a standard finite
population correction (FPC) conversely leads to underestimation of variance. We
uncover a way to leverage the typical FPC indirectly toward valid statistical
inference. In particular, we derive a readily estimable extra variance
component induced by misclassification in this specific but arguably common
diagnostic testing scenario. Our approach yields a standard error estimate that
properly captures the sampling variability of the usual bias-corrected maximum
likelihood estimator of disease prevalence. Finally, we develop an adapted
Bayesian credible interval for the true prevalence that offers improved
frequentist properties (i.e., coverage and width) relative to a Wald-type
confidence interval. We report the simulation results to demonstrate the
enhanced performance of the proposed inferential methods
Tailoring Capture-Recapture Methods to Estimate Registry-Based Case Counts Based on Error-Prone Diagnostic Signals
Surveillance research is of great importance for effective and efficient
epidemiological monitoring of case counts and disease prevalence. Taking
specific motivation from ongoing efforts to identify recurrent cases based on
the Georgia Cancer Registry, we extend recently proposed "anchor stream"
sampling design and estimation methodology. Our approach offers a more
efficient and defensible alternative to traditional capture-recapture (CRC)
methods by leveraging a relatively small random sample of participants whose
recurrence status is obtained through a principled application of medical
records abstraction. This sample is combined with one or more existing
signaling data streams, which may yield data based on arbitrarily
non-representative subsets of the full registry population. The key extension
developed here accounts for the common problem of false positive or negative
diagnostic signals from the existing data stream(s). In particular, we show
that the design only requires documentation of positive signals in these
non-anchor surveillance streams, and permits valid estimation of the true case
count based on an estimable positive predictive value (PPV) parameter. We
borrow ideas from the multiple imputation paradigm to provide accompanying
standard errors, and develop an adapted Bayesian credible interval approach
that yields favorable frequentist coverage properties. We demonstrate the
benefits of the proposed methods through simulation studies, and provide a data
example targeting estimation of the breast cancer recurrence case count among
Metro Atlanta area patients from the Georgia Cancer Registry-based Cancer
Recurrence Information and Surveillance Program (CRISP) database
Improving the Performance at Elevated Temperature of High Voltage Graphite/LiNi\u3csub\u3e0.5\u3c/sub\u3eMn\u3csub\u3e1.5\u3c/sub\u3eO\u3csub\u3e4\u3c/sub\u3e Cells with Added Lithium Catechol Dimethyl Borate
Performance of LiNi0.5Mn1.5O4/graphite cells cycled to 4.8 V at 55°C with the 1.2 M LiPF6 in EC/EMC (3/7, STD electrolyte) with and without added lithium catechol dimethyl borate (LiCDMB) has been investigated. The incorporation of 0.5 wt% LiCDMB to the STD electrolyte results in an improved capacity retention and coulombic efficiency upon cycling at 55°C. Ex-situ analysis of the electrode surfaces via a combination of SEM, TEM, and XPS reveals that oxidation of LiCDMB at high potential results in the deposition of a passivation layer on the electrode surface, preventing transition metal ion dissolution from the cathode and subsequent deposition on the anode. NMR investigations of the bulk electrolyte stored at 85°C reveals that added LiCDMB prevents the thermal decomposition of LiPF6
A Facile Synthesis of ZnCo\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e4\u3c/sub\u3e Nanocluster Particles and the Performance as Anode Materials for Lithium Ion Batteries
ZnCo2O4 nanocluster particles (NCPs) were prepared through a designed hydrothermal method, with the assistance of a surfactant, sodium dodecyl benzene sulfonate. The crystalline structure and surface morphology of ZnCo2O4 were investigated by XRD, XPS, SEM, TEM, and BET analyses. The results of SEM and TEM suggest a clear nanocluster particle structure of cubic ZnCo2O4 (~100 nm in diameter), which consists of aggregated primary nanoparticles (~10 nm in diameter), is achieved. The electrochemical behavior of synthesized ZnCo2O4 NCPs was investigated by galvanostatic discharge/charge measurements and cyclic voltammetry. The ZnCo2O4 NCPs exhibit a high reversible capacity of 700 mAh g−1 over 100 cycles under a current density of 100 mA g−1 with an excellent coulombic efficiency of 98.9% and a considerable cycling stability. This work demonstrates a facile technique designed to synthesize ZnCo2O4 NCPs which show great potential as anode materials for lithium ion batteries
Performance of the 1-ton Prototype Neutrino Detector at CJPL-I
China Jinping Underground Laboratory (CJPL) provides an ideal site for solar,
geo-, and supernova neutrino studies. With a prototype neutrino detector
running since 2017, containing 1-ton liquid scintillator (LS), we tested its
experimental hardware, performed the physics calibration, and measured its
radioactive backgrounds, as an early stage of the Jinping Neutrino Experiment
(JNE). We investigated the radon background and implemented the nitrogen
sealing technology to control it. This paper presents the details of these
studies and will serve as a key reference for the construction and optimization
of the future large detector at JNE
Mixed-Phoneme BERT: Improving BERT with Mixed Phoneme and Sup-Phoneme Representations for Text to Speech
Recently, leveraging BERT pre-training to improve the phoneme encoder in text
to speech (TTS) has drawn increasing attention. However, the works apply
pre-training with character-based units to enhance the TTS phoneme encoder,
which is inconsistent with the TTS fine-tuning that takes phonemes as input.
Pre-training only with phonemes as input can alleviate the input mismatch but
lack the ability to model rich representations and semantic information due to
limited phoneme vocabulary. In this paper, we propose MixedPhoneme BERT, a
novel variant of the BERT model that uses mixed phoneme and sup-phoneme
representations to enhance the learning capability. Specifically, we merge the
adjacent phonemes into sup-phonemes and combine the phoneme sequence and the
merged sup-phoneme sequence as the model input, which can enhance the model
capacity to learn rich contextual representations. Experiment results
demonstrate that our proposed Mixed-Phoneme BERT significantly improves the TTS
performance with 0.30 CMOS gain compared with the FastSpeech 2 baseline. The
Mixed-Phoneme BERT achieves 3x inference speedup and similar voice quality to
the previous TTS pre-trained model PnG BERTComment: submitted to interspeech 202
Optical and microstructural characterization of Er doped epitaxial cerium oxide on silicon
Rare-earth ion dopants in solid-state hosts are ideal candidates for quantum
communication technologies such as quantum memory, due to the intrinsic
spin-photon interface of the rare-earth ion combined with the integration
methods available in the solid-state. Erbium-doped cerium oxide (Er:CeO) is
a particularly promising platform for such a quantum memory, as it combines the
telecom-wavelength (~1.5 m) 4f-4f transition of erbium, a predicted long
electron spin coherence time supported by CeO, and is also near
lattice-matched to silicon for heteroepitaxial growth. In this work, we report
on the epitaxial growth of Er:CeO thin films on silicon using molecular
beam epitaxy (MBE), with controlled erbium concentration down to 2 parts per
million (ppm). We carry out a detailed microstructural study to verify the
CeO host structure, and characterize the spin and optical properties of the
embedded Er ions. In the 2-3 ppm Er regime, we identify EPR linewidths
of 245(1) MHz, optical inhomogeneous linewidths of 9.5(2) GHz, optical excited
state lifetimes of 3.5(1) ms, and spectral diffusion-limited homogenoeus
linewidths as narrow as 4.8(3) MHz in the as-grown material. We test annealing
of the Er:CeO films up to 900 deg C, which yields modest narrowing of the
inhomogeneous linewidth by 20% and extension of the excited state lifetime by
40%. We have also studied the variation of the optical properties as a function
of Er doping and find that the results are consistent with the trends expected
from inter-dopant charge interactions.Comment: 15 pages, 6 figures (including supplemental information
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