Conflicting evidence exists on whether physical activity (PA) levels of humans have changed over the last quarter-century. The main objective of this study was to determine if there is evidence of ...time trends in PA, from cross-sectional studies that assessed PA at different time points using wearable devices (e.g., pedometers and accelerometers). A secondary objective was to quantify the rate of change in PA.
A systematic literature review was conducted of English-language studies indexed in PubMed, SPORTDiscus, and Web of Science (1960-2020) using search terms (time OR temporal OR secular) AND trends AND (steps per day OR pedometer OR accelerometer OR MVPA). Subsequently, a meta-analytic approach was used to aggregate data from multiple studies and to examine specific factors (i.e., sex, age-group, sex and age-group, and PA metric).
Based on 16 peer-reviewed scientific studies conducted between 1995 and 2017, levels of ambulatory PA are trending downward in developed countries. Significant declines were seen in both males and females (P < 0.001) as well as in children (P = 0.020), adolescents (P < 0.001), and adults (P = 0.004). The average study duration was 9.4 yr (accelerometer studies, 5.3 yr; pedometer studies, 10.8 yr). For studies that assessed steps, the average change in PA was -1118 steps per day over the course of the study (P < 0.001), and adolescents had the greatest change in PA at -2278 steps per day (P < 0.001). Adolescents also had the steepest rate of change over time, expressed in steps per day per decade.
Evidence from studies conducted in eight developed nations over a 22-yr period indicates that PA levels have declined overall, especially in adolescents. This study emphasizes the need for continued research tracking time trends in PA using wearable devices.
A large scale scintillating fiber tracker using visible light photon counter (VLPC) readout was built as a prototype far the upgraded DO central tracker. This prototype has been under test at ...Fermilab for six months using cosmic rays. A description of the components of the tracker including the photodetector, fibers, lightguides, ribbons, and DAQ is given. Preliminary results on detected photon yield, position resolution, efficiency and VLPC performance are presented.< >
We present a measurement of the transverse momentum distribution of Z bosons produced in ppbar collisions at sqrt{s}=1.8 TeV using data collected by the D0 experiment at the Fermilab Tevatron ...Collider during 1994--1996. We find good agreement between our data and a current resummation calculation. We also use our data to extract values of the non-perturbative parameters for a particular version of the resummation formalism, obtaining significantly more precise values than previous determinations.
This Letter describes a measurement of the muon cross section originating from b quark decay in the forward rapidity range 2.4 y(mu) 3.2 in pbarp collisions at sqrt(s) = 1.8 TeV. The data used in ...this analysis were collected by the D0 experiment at the Fermilab Tevatron. We find that NLO QCD calculations underestimate b quark production by a factor of four in the forward rapidity region.
We report on a search for second generation leptoquarks (LQ) produced in $p\bar{p}$ collisions at sqrt{s} = 1.8 TeV using the D0 detector at Fermilab. Second generation leptoquarks are assumed to be ...produced in pairs and to decay to either \mu or \nu and either a strange or a charm quark (q). Limits are placed on \sigma(p-pbar -> LQ-LQbar -> \mu\nu + jets) as a function of the mass of the leptoquark. For equal branching ratios to \mu q and \nu q, second generation scalar leptoquarks with a mass below 160 GeV/c^2, vector leptoquarks with anomalous minimal vector couplings with a mass below 240 GeV/c^2, and vector leptoquarks with Yang-Mills couplings with a mass below 290 GeV/c^2, are excluded at the 95% confidence level.
We report the results of a study of color coherence effects in ppbar collisions based on data collected by the D0 detector during the 1994-1995 run of the Fermilab Tevatron Collider, at a center of ...mass energy sqrt(s) = 1.8 TeV. Initial-to-final state color interference effects are studied by examining particle distribution patterns in events with a W boson and at least one jet. The data are compared to Monte Carlo simulations with different color coherence implementations and to an analytic modified-leading-logarith m perturbative calculation based on the local parton-hadron duality hypothesis.
The ital WWgamma gauge boson couplings were measured using ital pbar pr arrowlnugamma+ital X (l=ital e,mu) events at radicalital s=1.8 TeV observed with the D0 detector at the Fermilab Tevatron ...Collider. The signal, obtained from the data corresponding to an integrated luminosity of 13.8pbsup minus1, agrees well with the standard model prediction. A fit to the photon transverse energy spectrum yields limits at the 95% confidence level on the ital CP-conserving anomalous coupling parameters of minus1.6ltDeltakappalt1.8 (lambda=0) and minus0.6ltlambdalt0.6 (Deltakappa=0). Similar limits are obtained for the ital CP-violating coupling parameters.
First experimental results are presented from a search for events with a rapidity gap between jets. The D0 detector was used to examine events produced by the Fermilab Tevatron ital pbar p collider ...at radicalital s =1.8 TeV. The fraction of events with an observed rapidity gap between the two highest transverse energy (ital Esub ital T) jets is measured as a function of the pseudorapidity separation between the jet edges (Deltaetasub ital c). An upper limit at the 95% confidence level of 1.1times10sup minus2 is obtained on the fraction of events with non particles between the jets, for events with Deltaetasub ital cgt3 and jet ital Esub ital T greater than 30 GeV.
We have searched for evidence of top quark production in ital pbar p collisions at radicalital s =1.8 TeV using the ital D0 detector at the Fermilab Tevatron collider. For an integrated luminosity of ...15 pbsup minus1, we report results of a search for ital tbar t pairs in the decay modes ital tbar tr arrowital emu+jets,ital ee+jets,ital e+jets, and mu+jets. From analyses of these modes we obtain a lower limit on the top quark mass of 131 GeV/ital csup 2 at the 95% confidence level, assuming standard model branching fractions and a predicted cross section for ital tbar t production. We discuss the properties of an event for which expected backgrounds are small.
We report on a search for first generation leptoquarks with the DO detector at the Fermilab Tevatron ital pbar p collider at radicalital s =1.8 TeV. This search is based on 15 pbsup minus1 of data. ...Leptoquarks are assumed to be produced in pairs and to decay into an electron + quark with branching ratio beta. No leptoquark candidates were found. We obtain cross section times branching ratio limits as a function of leptoquark mass. For pair production of scalar leptoquarks, we set a leptoquark mass limit of 133 GeV for beta=1 and 120 GeV for beta=0.5 at 95% confidence level.
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