ORCID Profile
0000-0001-8037-3103
Current Organisations
National Cancer Institute
,
Friedrich-Alexander-Universität Erlangen-Nürnberg
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Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 11-2005
DOI: 10.1249/01.MSS.0000185674.09066.8A
Abstract: Accelerometers are recognized as a valid and objective tool to assess free-living physical activity. Despite the widespread use of accelerometers, there is no standardized way to process and summarize data from them, which limits our ability to compare results across studies. This paper a) reviews decision rules researchers have used in the past, b) compares the impact of using different decision rules on a common data set, and c) identifies issues to consider for accelerometer data reduction. The methods sections of studies published in 2003 and 2004 were reviewed to determine what decision rules previous researchers have used to identify wearing period, minimal wear requirement for a valid day, spurious data, number of days used to calculate the outcome variables, and extract bouts of moderate to vigorous physical activity (MVPA). For this study, four data reduction algorithms that employ different decision rules were used to analyze the same data set. The review showed that among studies that reported their decision rules, much variability was observed. Overall, the analyses suggested that using different algorithms impacted several important outcome variables. The most stringent algorithm yielded significantly lower wearing time, the lowest activity counts per minute and counts per day, and fewer minutes of MVPA per day. An exploratory sensitivity analysis revealed that the most stringent inclusion criterion had an impact on s le size and wearing time, which in turn affected many outcome variables. These findings suggest that the decision rules employed to process accelerometer data have a significant impact on important outcome variables. Until guidelines are developed, it will remain difficult to compare findings across studies.
Publisher: Stichting SciPost
Date: 10-10-2022
DOI: 10.21468/SCIPOSTPHYS.13.4.088
Abstract: The hyperscaling relation and standard finite-size scaling (FSS) are known to break down above the upper critical dimension due to dangerous irrelevant variables. We establish a coherent formalism for FSS at quantum phase transitions above the upper critical dimension following the recently introduced Q-FSS formalism for thermal phase transitions. Contrary to long-standing belief, the correlation sector is affected by dangerous irrelevant variables. The presented formalism recovers a generalized hyperscaling relation and FSS form. Using this new FSS formalism, we determine the full set of critical exponents for the long-range transverse-field Ising chain in all criticality regimes ranging from the nearest-neighbor to the long-range mean-field regime. For the same model, we also explicitly confirm the effect of dangerous irrelevant variables on the characteristic length scale.
Publisher: American Physical Society (APS)
Date: 07-10-2019
Publisher: Springer Science and Business Media LLC
Date: 04-09-2011
Publisher: American Physical Society (APS)
Date: 23-06-2021
Publisher: Elsevier BV
Date: 08-2011
Publisher: American Physical Society (APS)
Date: 12-11-2020
Publisher: Wiley
Date: 16-10-2019
DOI: 10.3322/CAAC.21579
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 07-2010
Publisher: Oxford University Press (OUP)
Date: 11-01-2011
Publisher: Stichting SciPost
Date: 30-05-2023
DOI: 10.21468/SCIPOSTPHYS.14.5.136
Abstract: We propose a general approach to analyse diagonal ordering patterns in bosonic lattice models with algebraically decaying density-density interactions on arbitrary lattices. The key idea is a systematic search for the energetically best order on all unit cells of the lattice up to a given extent. Using resummed couplings we evaluate the energy of the ordering patterns in the thermodynamic limit using finite unit cells. We apply the proposed approach to the atomic limit of the extended Bose-Hubbard model on the triangular lattice at fillings f=1/2 f = 1 / 2 and f=1 f = 1 . We investigate the ground-state properties of the antiferromagnetic long-range Ising model on the triangular lattice and determine a six-fold degenerate plain-stripe phase to be the ground state for finite decay exponents. We also probe the classical limit of the Fendley-Sengupta-Sachdev model describing Rydberg atom arrays. We focus on arrangements where the atoms are placed on the sites or links of the Kagome lattice. Our method provides a general framework to treat cristalline structures resulting from long-range interactions.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2011
Publisher: American Association for Cancer Research (AACR)
Date: 05-2014
DOI: 10.1158/1055-9965.EPI-13-0808
Abstract: Sedentary behavior (sitting time) has been proposed as an independent risk factor for some cancers however, its role in the development of prostate cancer has not been determined. We examined the prospective associations of self-reported daily sitting time and daily television/video viewing time with the risk of developing or dying from prostate cancer among 170,481 men in the NIH–AARP Diet and Health Study. We estimated HRs and 95% confidence intervals (CI) using Cox proportional hazards regression. Between 1996 and 2006, there were 13,751 incident (including 1,365 advanced) prostate cancer cases identified prostate cancer mortality (through 2008) was 669. No strong or significant association with prostate cancer risk was seen in fully adjusted models for either daily sitting or television/video time. There were some suggestions of effect modification by body mass index (BMI interaction for television/video time and BMI, P = 0.02). For total prostate cancer risk, television/video time was associated with a slightly elevated, but nonsignificant, increase amongst obese men (HR = 1.28 95% CI, 0.98–1.69) a null association was observed amongst overweight men (HR = 1.04 0.89–1.22) and, for men with a normal BMI, television/video time was associated with a nonsignificant risk decrease (HR = 0.82 95% CI, 0.66–1.01). Similar patterns were observed for total daily sitting and television/video time in advanced prostate cancer and prostate cancer mortality. Sedentary behavior seems to play a limited role in the development of prostate cancer however, we cannot rule out potential effect modification by BMI or the impact of measurement error on results. Cancer Epidemiol Biomarkers Prev 23(5) 882–9. ©2014 AACR.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 07-2010
Publisher: Elsevier BV
Date: 12-2010
Publisher: BMJ
Date: 18-04-2012
Publisher: Public Library of Science (PLoS)
Date: 13-11-2013
Location: United States of America
Location: United States of America
No related grants have been discovered for charles matthews.