840 research outputs found
Closure of two dimensional turbulence: the role of pressure gradients
Inverse energy cascade regime of two dimensional turbulence is investigated
by means of high resolution numerical simulations. Numerical computations of
conditional averages of transverse pressure gradient increments are found to be
compatible with a recently proposed self-consistent Gaussian model. An
analogous low order closure model for the longitudinal pressure gradient is
proposed and its validity is numerically examined. In this case numerical
evidence for the presence of higher order terms in the closure is found. The
fundamental role of conditional statistics between longitudinal and transverse
components is highlighted.Comment: 4 pages, 2 figures, in press on PR
Generalized Analysis of Weakly-Interacting Massive Particle Searches
We perform a generalized analysis of data from WIMP search experiments for
point-like WIMPs of arbitrary spin and general Lorenz-invariant WIMP-nucleus
interaction. We show that in the non-relativistic limit only spin-independent
(SI) and spin-dependent (SD) WIMP-nucleon interactions survive, which can be
parameterized by only five independent parameters. We explore this
five-dimensional parameter space to determine whether the annual modulation
observed in the DAMA experiment can be consistent with all other experiments.
The pure SI interaction is ruled out except for very small region of parameter
space with the WIMP mass close to 50 GeV and the ratio of the WIMP-neutron to
WIMP-proton SI couplings . For the predominantly SD
interaction, we find an upper limit to the WIMP mass of about 18 GeV, which can
only be weakened if the constraint stemming from null searches for energetic
neutrinos from WIMP annihilation the Sun is evaded. None of the regions of the
parameter space that can reconcile all WIMP search results can be easily
accommodated in the minimal supersymmetric extension of the standard model.Comment: 27 pages, 3 figure
AKAP-Lbc mobilizes a cardiac hypertrophy signaling pathway.
Elevated catecholamines in the heart evoke transcriptional activation of the Myocyte Enhancer Factor (MEF) pathway to induce a cellular response known as pathological myocardial hypertrophy. We have discovered that the A-Kinase Anchoring Protein (AKAP)-Lbc is upregulated in hypertrophic cardiomyocytes. It coordinates activation and movement of signaling proteins that initiate MEF2-mediated transcriptional reprogramming events. Live-cell imaging, fluorescent kinase activity reporters, and RNA interference techniques show that AKAP-Lbc couples activation of protein kinase D (PKD) with the phosphorylation-dependent nuclear export of the class II histone deacetylase HDAC5. These studies uncover a role for AKAP-Lbc in which increased expression of the anchoring protein selectively amplifies a signaling pathway that drives cardiac myocytes toward a pathophysiological outcome
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Reframing physically active learning as movement-centred pedagogy: a European priority action framework
YesPhysically active learning (PAL) has emerged as a promising way of eliciting health and education-based outcomes for pupils. Concurrently, research suggests large variability in how PAL is perceived, operationalized, and prioritized in practice across Europe. Therefore, this study aimed to co-develop a framework for action to support the adoption and implementation of PAL.
Adopting a design thinking approach, 40 international stakeholders representing 13 countries engaged in an idea generation workshop during a two-day PAL international conference. Participants included professionals from research (n = 20), practice (n = 4) and policy (n = 1) or a combination (n = 15). Their experience with PAL ranged from none to 19 years (with an average of 3.9 years). Participants were allocated into one of six heterogeneous and multidisciplinary groups and led through interactive tasks to identify: the landscape for PAL across Europe, barriers to the adoption and implementation of PAL, and key objectives for research, policy and practice to improve the adoption and implementation of PAL. All discussions were audio recorded and prioritized objectives were transcribed verbatim and analysed using inductive qualitative content analysis.
Five interlinked and mutually reinforcing themes were identified: (1) Integration of the health and education paradigms (2) Coherent national policy and decision making (3) Building confident and competent teachers (4) Adopting a whole school approach for PAL (5) Strengthening the evidence base for PAL.
The priority action framework identifies five key areas for action to facilitate PAL adoption and implementation across Europe. Central to the success of border uptake of PAL is the integration of the health and education paradigms. To achieve this aim, reframing PAL as movement-centered pedagogy would provide a more holistic and inclusive perspective.The authors of this manuscript were supported and funded by the European Union ERASMUS + Strategic Partnership Fund as part of the Activating Classroom Teachers project, ACTivate (Grant no 2019-1-N001-KA203-063024)
Performance Analysis of Signaling Delay for Wireless Cellular Networks
In wireless cellular networks, signaling traffic such as location update, paging and handoff due to the user\u27s mobility takes a considerable portion of the total traffic load. In addition, the maximum allowable delays may be different among the signaling packets. In this paper, we present an analytical model for evaluating a total processing delay of signaling packets of wireless cellular networks, which integrates the delays of the radio channel and the processing delay at the wired portion. Through numerical examples, we show that priority processing is effective for reducing the handoff processing delays. We also evaluate the delay difference among cells according to their position within the location area, and the influence of number of terminals upon the processing delays
Leading Order Textures for Lepton Mass Matrices
In theories with three light neutrinos, certain simplicity assumptions allow
the construction of a complete list of leading order lepton mass matrices.
These matrices are consistent with m_{tau} \neq 0, Delta m^2_{12} \ll Delta
m^2_{23}, theta_{23} approx 1, and theta_{13} = 0, as suggested by measurements
of atmospheric and solar neutrino fluxes. The list contains twelve generic
cases: two have three degenerate neutrinos, eight have two neutrinos forming a
Dirac state, and in only two cases is one neutrino much heavier than the other
two. For each of these twelve generic cases the possible forms for the
perturbations which yield m_{mu} are given. Ten special textures are also
found.Comment: 17 pages, added reference
Teachers' Perspectives on the Acceptability and Feasibility of Wearable Technology to Inform School-Based Physical Activity Practices
YesBackground: Many children are not engaging in sufficient physical activity and there are substantial between-children physical activity inequalities. In addition to their primary role as educators, teachers are often regarded as being well-placed to make vital contributions to inclusive visions of physical activity promotion. With the dramatic increase in popularity of wearable technologies for physical activity promotion in recent years, there is a need to better understand teachers' perspectives about using such devices, and the data they produce, to support physical activity promotion in schools. Method: Semi-structured interviews were conducted with 26 UK-based primary school teachers, exploring their responses to children's physical activity data and their views about using wearable technologies during the school day. Interview discussions were facilitated by an elicitation technique whereby participants were presented with graphs illustrating children's in-school physical activity obtained from secondary wearable technology data. Interview transcripts were thematically analyzed. Results: Most teachers spoke positively about the use of wearable technologies specifically designed for school use, highlighting potential benefits and considerations. Many teachers were able to understand and critically interpret data showing unequal physical activity patterns both within-and between-schools. Being presented with the data prompted teachers to provide explanations about observable patterns, emotional reactions-particularly about inequalities-and express motivations to change the current situations in schools. Conclusion: These findings suggest that primary school teachers in the UK are open to integrating wearable technology for measuring children's physical activity into their practices and can interpret the data produced by such devices. Visual representations of physical activity elicited strong responses and thus could be used when working with teachers as an effective trigger to inform school practices and policies seeking to address in-school physical inactivity and inequalities
Observations of quasi-periodic solar X-ray emission as a result of MHD oscillations in a system of multiple flare loops
We investigate the solar flare of 20 October 2002. The flare was accompanied
by quasi-periodic pulsations (QPP) of both thermal and nonthermal hard X-ray
emissions (HXR) observed by RHESSI in the 3-50 keV energy range. Analysis of
the HXR time profiles in different energy channels made with the Lomb
periodogram indicates two statistically significant time periods of about 16
and 36 seconds. The 36-second QPP were observed only in the nonthermal HXR
emission in the impulsive phase of the flare. The 16-second QPP were more
pronounced in the thermal HXR emission and were observed both in the impulsive
and in the decay phases of the flare. Imaging analysis of the flare region, the
determined time periods of the QPP and the estimated physical parameters of
magnetic loops in the flare region allow us to interpret the observations as
follows. 1) In the impulsive phase energy was released and electrons were
accelerated by successive acts with the average time period of about 36 seconds
in different parts of two spatially separated, but interacting loop systems of
the flare region. 2) The 36-second periodicity of energy release could be
caused by the action of fast MHD oscillations in the loops connecting these
flaring sites. 3) During the first explosive acts of energy release the MHD
oscillations (most probably the sausage mode) with time period of 16 seconds
were excited in one system of the flare loops. 4) These oscillations were
maintained by the subsequent explosive acts of energy release in the impulsive
phase and were completely damped in the decay phase of the flare.Comment: 14 pages, 4 figure
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