1,332 research outputs found
Relating outdoor play to sedentary behavior and physical activity in youth - results from a cohort study
Background
Outdoor play, sedentary behavior (SB), and moderate-to-vigorous physical activity (MVPA) are related to youthās health, however, there are research gaps regarding 1) associations between outdoor play, SB, and MVPA across a broad pediatric age range (6ā17āyears), and 2) longitudinal associations between outdoor play, SB, and MVPA across childhood and adolescence. Two studies were conducted to address those research gaps: Study 1 aimed to investigate relationships between outdoor play and accelerometer-assessed SB and MVPA in a cross-sectional nationwide sample of children and adolescents in Germany. Study 2 aimed to investigate prospective associations between outdoor play and self-reported screen-time SB and MVPA and in a sample of children with three measurement timepoints across 11āyears.
Methods
Data were obtained of the German national representative Motorik-Modul (MoMo) Study and the German Health Interview and Examination Survey for Children and Adolescents (KiGGS). In Study 1, Nā=ā2278 participants (6ā17āyears) were included with self-reported outdoor play and accelerometer-assessed SB and MVPA. Associations were examined via multiple linear regressions. In Study 2, Nā=ā570 participants (baseline: 4ā7āyears) were included in the longitudinal analysis with follow-ups six and 11āyears later. Screen-time SB (TV watching and PC/Gaming), MVPA, and outdoor play were self-reported. Associations were investigated through a path prediction model.
Results
Study 1 showed that compared to <1āh outdoor play, higher engagement in daily outdoor play was related to lower SB (1-2āh: āā9.75āmin/day, Pā=ā0.017; ā„2āh: āā17.78āmin/day, Pā<ā0.001) and higher MVPA (ā„2āh: +ā3.87āmin/day, Pā=ā0.001). The cross-sectional relationship between MVPA and outdoor play was moderated by sex (in favor of males) and age (in favor of younger children). Study 2 showed that outdoor play in early childhood negatively predicted PC use/Gaming in later childhood, but was unrelated to MVPA.
Conclusion
In Study 1, outdoor play was negatively related to SB cross-sectionally. In Study 2, outdoor play in early childhood was negatively related to PC and Gaming time in later childhood. Thus, providing outdoor play opportunities, especially during early childhood, has potential to prevent SB. Future research should investigate longitudinal relationships using device-based assessments for SB and MVPA
The Influence of Foot Positioning on Ankle Sprains
The goal of this study was to examine the influence of changes in foot positioning at touch-down on ankle sprain occurrence. Muscle model driven computer simulations of 10 subjects performing the landing phase of a side-shuffle movement were performed. The relative subtalar joint and talocural joint angles at touchdown were varied, and each subject-specific simulation was exposed to a set of perturbed floor conditions. The touchdown subtalar joint angle was not found to have a considerable influence on sprain occurrence, while increased touchdown plantar flexion caused increased ankle sprain occurrences. Increased touchdown plantar flexion may be the mechanism which causes ankles with a history of ankle sprains to have an increased susceptibility to subsequent sprains. This finding may also reveal a mechanism by which taping of a sprained ankle or the application of an ankle brace leads to decreased ankle sprain susceptibility
Real-time dynamics of lattice gauge theories with a few-qubit quantum computer
Gauge theories are fundamental to our understanding of interactions between
the elementary constituents of matter as mediated by gauge bosons. However,
computing the real-time dynamics in gauge theories is a notorious challenge for
classical computational methods. In the spirit of Feynman's vision of a quantum
simulator, this has recently stimulated theoretical effort to devise schemes
for simulating such theories on engineered quantum-mechanical devices, with the
difficulty that gauge invariance and the associated local conservation laws
(Gauss laws) need to be implemented. Here we report the first experimental
demonstration of a digital quantum simulation of a lattice gauge theory, by
realising 1+1-dimensional quantum electrodynamics (Schwinger model) on a
few-qubit trapped-ion quantum computer. We are interested in the real-time
evolution of the Schwinger mechanism, describing the instability of the bare
vacuum due to quantum fluctuations, which manifests itself in the spontaneous
creation of electron-positron pairs. To make efficient use of our quantum
resources, we map the original problem to a spin model by eliminating the gauge
fields in favour of exotic long-range interactions, which have a direct and
efficient implementation on an ion trap architecture. We explore the Schwinger
mechanism of particle-antiparticle generation by monitoring the mass production
and the vacuum persistence amplitude. Moreover, we track the real-time
evolution of entanglement in the system, which illustrates how particle
creation and entanglement generation are directly related. Our work represents
a first step towards quantum simulating high-energy theories with atomic
physics experiments, the long-term vision being the extension to real-time
quantum simulations of non-Abelian lattice gauge theories
Implementing and characterizing precise multi-qubit measurements
There are two general requirements to harness the computational power of
quantum mechanics: the ability to manipulate the evolution of an isolated
system and the ability to faithfully extract information from it. Quantum error
correction and simulation often make a more exacting demand: the ability to
perform non-destructive measurements of specific correlations within that
system. We realize such measurements by employing a protocol adapted from [S.
Nigg and S. M. Girvin, Phys. Rev. Lett. 110, 243604 (2013)], enabling real-time
selection of arbitrary register-wide Pauli operators. Our implementation
consists of a simple circuit quantum electrodynamics (cQED) module of four
highly-coherent 3D transmon qubits, collectively coupled to a high-Q
superconducting microwave cavity. As a demonstration, we enact all seven
nontrivial subset-parity measurements on our three-qubit register. For each we
fully characterize the realized measurement by analyzing the detector
(observable operators) via quantum detector tomography and by analyzing the
quantum back-action via conditioned process tomography. No single quantity
completely encapsulates the performance of a measurement, and standard figures
of merit have not yet emerged. Accordingly, we consider several new fidelity
measures for both the detector and the complete measurement process. We measure
all of these quantities and report high fidelities, indicating that we are
measuring the desired quantities precisely and that the measurements are highly
non-demolition. We further show that both results are improved significantly by
an additional error-heralding measurement. The analyses presented here form a
useful basis for the future characterization and validation of quantum
measurements, anticipating the demands of emerging quantum technologies.Comment: 10 pages, 5 figures, plus supplemen
Trends in alcohol use among Hawaiāi adolescents
It is important to review trends in youth alcohol use over time in order to effectively tailor prevention programs to address those trends. This article reviews data on alcohol use behaviors from the Centers for Disease Control and Prevention\u27s Youth Risk Behavior Survey in Hawaiāi from 1993 to 2007. Five alcohol use indicators were examined and stratified by grade level, from 9th grade through 12th grade. Significant drops in nearly all indicators are seen among 9th through 11th graders, but not among 12th graders. This suggests that Hawaiāi youth are responding well to anti-alcohol messaging as young teens, but a different approach may be needed to target older teens
Predictors of Change in Physical Activity and Fruit and Vegetable Intake in a Multiethnic Population in Hawaii at 6 and 12 Months Follow-up
Health-promoting behaviors have been shown to co-exist, but it is unknown if decisional balance with regards to one health behavior may predict change in another behavior. The objective of this study was to examine the relationship between benefits (pros) and costs (cons) of fruit and vegetable (FV) intake and physical activity (PA) and behavior over time, both within behaviors and transbehaviorally. This longitudinal study was conducted in multiethnic adults in Hawaii (n = 700; 63% female; mean age = 47 years; mean BMI = 25.9; mean education = 14.5 years, average household income = $45,000/year). Questionnaires assessed PA and FV pros/cons on a 5-point Likert Scale, PA (MET-min/wk), and FV intake (servings/day). Multiple regression was used to examine the relationship between pros/cons for PA and FV intake and behavior at 6- and 12-month follow-up. At baseline, average FV pros were 4.08 (.91), and average FV cons were 1.88 (.90). Average baseline PA pros were 4.07 (.89), and average PA cons were 1.71 (.77). Multiple regressions revealed that baseline FV pros and cons predicted FV intake, FV cons also predicted PA, and PA pros and cons were not predictive of PA or of FV intake. Study findings provide some support for decisional balance as a useful core construct used in leading theories of behavior change. Improving decisional balance for FV intake may have a beneficial effect on FV intake and potentially PA, indicating a potential gateway effect of decisional balance for FV intake on other behaviors
Which executive functioning deficits are associated with AD/HD, ODD/CD and comorbid AD/HD+ODD/CD?
Item does not contain fulltextThis study investigated (1) whether attention deficit/hyperactivity disorder (AD/HD) is associated with executive functioning (EF) deficits while controlling for oppositional defiant disorder/conduct disorder (ODD/CD), (2) whether ODD/CD is associated with EF deficits while controlling for AD/HD, and (3)~whether a combination of AD/HD and ODD/CD is associated with EF deficits (and the possibility that there is no association between EF deficits and AD/HD or ODD/CD in isolation). Subjects were 99~children ages 6ā12 years. Three putative domains of EF were investigated using well-validated tests: verbal fluency, working memory, and planning. Independent of ODD/CD, AD/HD was associated with deficits in planning and working memory, but not in verbal fluency. Only teacher rated AD/HD, but not parent rated AD/HD, significantly contributed to the prediction of EF task performance. No EF deficits were associated with ODD/CD. The presence of comorbid AD/HD accounts for the EF deficits in children with comorbid AD/HD+ODD/CD. These results suggest that EF deficits are unique to AD/HD and support the model proposed by R. A. Barkley (1997).17 p
Impact testing to determine the mechanical properties of articular cartilage in isolation and on bone
The original publication is available at www.springerlink.comNon peer reviewedPostprin
The fates of chicken nuclear lamin proteins during mitosis: evidence for a reversible redistribution of lamin B2 between inner nuclear membrane and elements of the endoplasmic reticulum.
Universal Resistances of the Quantum RC circuit
We examine the concept of universal quantized resistance in the AC regime
through the fully coherent quantum RC circuit comprising a cavity (dot)
capacitively coupled to a gate and connected via a single spin-polarized
channel to a reservoir lead. As a result of quantum effects such as the Coulomb
interaction in the cavity and global phase coherence, we show that the charge
relaxation resistance is identical for weak and large transmissions and
it changes from to when the frequency (times ) exceeds
the level spacing of the cavity; is the Planck constant and the
electron charge. For large cavities, we formulate a correspondence between the
charge relaxation resistance and the Korringa-Shiba relation of the
Kondo model. Furthermore, we introduce a general class of models, for which the
charge relaxation resistance is universal. Our results emphasize that the
charge relaxation resistance is a key observable to understand the dynamics of
strongly correlated systems.Comment: 12 pages, 3 figure
- ā¦