2,929 research outputs found
Lightning Detection and Ranging system LDAR system description and performance objectives
The instruments used at the six remote stations to measure both the time-of-arrival of the envelope of the pulsed 60 MHz to 80 MHz portion of the RF signal emitted by lightning, and the electric field waveforms are described as well as the two methods of transmitting the signal to the central station. Other topics discussed include data processing, recording, and reduction techniques and the software used for the 2100S, 2114, and 2116 computers
Conformity Through Fear: A Multimodal Critical Discourse Analysis of COVID-19 Information Adverts
The UK Government has produced an array of televised information adverts or ‘campaigns’ to increase public awareness of COVID-19 and promote compliance with its subsequent policy. Research has shown that compliance with public health policy is influenced by fearful visual-verbal campaign messaging strategies, and that emotive representations of ‘risk’ are generally perceived to be more effective than non-emotive discourse. However, how the Government has semiotically constructed and utilised fear within their COVID-19 campaigns to nudge public compliance remains unexplored. Preliminary analysis of seventeen COVID-19 adverts revealed four sequential phases to the Government’s pandemic response: responsibility, management, mitigation, and reflection. An in-depth Multimodal Critical Discourse Analysis of four selected adverts (one screenshot per advert, per phase), revealed that fear was constructed using less conventional meaning potentials in favour of more implicit multimodal semiotic interactions. By portraying a ‘good’ pandemic subject as one who makes ‘moral’ and ‘rational’ decisions to comply with COVID-19 policy, pre-existing societal inequalities which might hinder compliance, particularly for the socioeconomically disadvantaged groups of society, were reduced and problematised. This raises ethical concerns over notions of ‘expertise’ and the ‘rationalising’ of ‘irrational’ lifestyles. Future research should further explore multimodal nudges in public health campaigns to hold producers accountable
Associations between fibrin D-dimer, markers of inflammation, incident self-reported mobility limitation, and all-cause mortality in older men
Objectives<p></p>
To examine the independent relationships between fibrin D-dimer, interleukin 6 (IL-6), C-reactive protein (CRP), and fibrinogen and incident mobility limitation and mortality.<p></p>
Design<p></p>
Prospective.<p></p>
Setting<p></p>
General practice in 24 British towns.<p></p>
Participants<p></p>
Men aged 60 to 79 without prevalent heart failure followed up for an average of 11.5 years (N = 3,925).<p></p>
Measurements<p></p>
All-cause mortality (n = 1,286) and self-reported mobility disability obtained at examination in 1998 to 2000 and in a postal questionnaire 3 to 5 years later in 2003.<p></p>
Results<p></p>
High D-dimer (top vs lowest tertile: adjusted odds ratio (aOR) = 1.46, 95% confidence interval = 1.02–2.05) and IL-6 (aOR = 1.43, 95% CI = 1.01–2.02) levels (but not CRP or fibrinogen) were associated with greater incident mobility limitation after adjustment for confounders and prevalent disease status. IL-6, CRP, fibrinogen, and D-dimer were significantly associated with total mortality after adjustment for confounders. Only D-dimer and IL-6 predicted total mortality independent of each other and the other biomarkers. The adjusted hazard ratio (aHR) was 1.16 (95% CI = 1.10–1.22) for a standard deviation increase in log D-dimer and 1.10 (95% CI = 1.04–1.18) for a standard deviation increase in log IL-6. D-dimer was independently related to vascular and nonvascular mortality, and IL-6 was independently related to vascular mortality. Risks of mobility limitation and mortality were greatest in those with a combination of high D-dimer and IL-6 levels.<p></p>
Conclusion<p></p>
D-dimer and IL-6 are associated with risk of mobility limitation and mortality in older men without heart failure. The findings suggest that coagulation leads to functional decline and mortality s that inflammation does not explain
Scientific Machine Learning for Modeling and Simulating Complex Fluids
The formulation of rheological constitutive equations -- models that relate
internal stresses and deformations in complex fluids -- is a critical step in
the engineering of systems involving soft materials. While data-driven models
provide accessible alternatives to expensive first-principles models and less
accurate empirical models in many engineering disciplines, the development of
similar models for complex fluids has lagged. The diversity of techniques for
characterizing non-Newtonian fluid dynamics creates a challenge for classical
machine learning approaches, which require uniformly structured training data.
Consequently, early machine learning constitutive equations have not been
portable between different deformation protocols or mechanical observables.
Here, we present a data-driven framework that resolves such issues, allowing
rheologists to construct learnable models that incorporate essential physical
information, while remaining agnostic to details regarding particular
experimental protocols or flow kinematics. These scientific machine learning
models incorporate a universal approximator within a materially objective
tensorial constitutive framework. By construction, these models respect
physical constraints, such as frame-invariance and tensor symmetry, required by
continuum mechanics. We demonstrate that this framework facilitates the rapid
discovery of accurate constitutive equations from limited data, and that the
learned models may be used to describe more kinematically complex flows. This
inherent flexibility admits the application of these 'digital fluid twins' to a
range of material systems and engineering problems. We illustrate this
flexibility by deploying a trained model within a multidimensional
computational fluid dynamics simulation -- a task that is not achievable using
any previously developed data-driven rheological equation of state.Comment: 13 pages, 4 figure
The Medium Amplitude Response of Nonlinear Maxwell-Oldroyd Type Models in Simple Shear
A general framework for Maxwell-Oldroyd type differential constitutive models
is examined, in which an unspecified nonlinear function of the stress and
rate-of-deformation tensors is incorporated into the well-known corotational
version of the Jeffreys model discussed by Oldroyd. For medium amplitude simple
shear deformations, the recently developed mathematical framework of medium
amplitude parallel superposition (MAPS) rheology reveals that this generalized
nonlinear Maxwell model can produce only a limited number of distinct
signatures, which combine linearly in a well-posed basis expansion for the
third order complex viscosity. This basis expansion represents a library of
MAPS signatures for distinct constitutive models that are contained within the
generalized nonlinear Maxwell model. We describe a framework for quantitative
model identification using this basis expansion, and discuss its limitations in
distinguishing distinct nonlinear features of the underlying constitutive
models from medium amplitude shear stress data. The leading order contributions
to the normal stress differences are also considered, revealing that only the
second normal stress difference provides distinct information about the weakly
nonlinear response space of the model. After briefly considering the conditions
for time-strain separability within the generalized nonlinear Maxwell model, we
apply the basis expansion of the third order complex viscosity to derive the
medium amplitude signatures of the model in specific shear deformation
protocols. Finally, we use these signatures for estimation of model parameters
from rheological data obtained by these different deformation protocols,
revealing that three-tone oscillatory shear deformations produce data that is
readily able to distinguish all features of the medium amplitude, simple shear
response space of this generalized class of constitutive models.Comment: 26 pages, 11 figure
Resolved Kinematics of Runaway and Field OB Stars in the Small Magellanic Cloud
We use GAIA DR2 proper motions of the RIOTS4 field OB stars in the Small
Magellanic Cloud (SMC) to study the kinematics of runaway stars. The data
reveal that the SMC Wing has a systemic peculiar motion relative to the SMC Bar
of (v_RA, v_Dec) = (62 +/-7, -18+/-5) km/s and relative radial velocity +4.5
+/- 5.0 km/s. This unambiguously demonstrates that these two regions are
kinematically distinct: the Wing is moving away from the Bar, and towards the
Large Magellanic Cloud with a 3-D velocity of 64 +/- 10 km/s. This is
consistent with models for a recent, direct collision between the Clouds. We
present transverse velocity distributions for our field OB stars, confirming
that unbound runaways comprise on the order of half our sample, possibly more.
Using eclipsing binaries and double-lined spectroscopic binaries as tracers of
dynamically ejected runaways, and high-mass X-ray binaries (HMXBs) as tracers
of runaways accelerated by supernova kicks, we find significant contributions
from both populations. The data suggest that HMXBs have lower velocity
dispersion relative to dynamically ejected binaries, consistent with the former
corresponding to less energetic supernova kicks that failed to unbind the
components. Evidence suggests that our fast runaways are dominated by
dynamical, rather than supernova, ejections.Comment: Accepted to ApJ Letters. 10 pages, 4 figure
Trajectories of objectively measured physical activity in free-living older men.
BACKGROUND: The steep decline in physical activity (PA) among the oldest old is not well understood; there is little information about the patterns of change in PA and sedentary behaviour (SB) in older people. Longitudinal data on objectively measured PA data can give insights about how PA and SB change with age.
METHODS: Men age 70-90 yr, from a United Kingdom population-based cohort wore a GT3X accelerometer over the hip annually on up to three occasions (56%, 50%, and 51% response rates) spanning 2 yr. Multilevel models were used to estimate change in activity. Men were grouped according to achieving ≥150 min·wk of MVPA in bouts of ≥10 min (current guidelines) at two or three time points.
RESULTS: A total of 1419 ambulatory men had ≥600 min wear time on ≥3 d at ≥2 time points. At baseline, men took 4806 steps per day and spent 72.5% of their day in SB, 23.1% in light PA, and 4.1% in moderate-to-vigorous PA (MVPA). Mean change per year was -341 steps, +1.1% SB, -0.7% light PA, and -0.4% MVPA each day (all P 30 min increased from 5.1 by 0.1 per year (P = 0.02).
CONCLUSIONS: Among older adults, the steep decline in total PA occurred because of reductions in MVPA, while light PA is relatively spared and sedentary time and long sedentary bouts increase
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