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Evaluation of a wearable computer system for telemonitoring in a critical environment
This paper reports on the evaluation of a wearable computer system designed for use in a critical environment, namely the intensive care unit of a hospital. The nature of the application raised ethical issues for testing in a clinical environment and standard evaluation techniques could not easily be applied. The system was therefore evaluated by clinicians in a multi-tasking environment with a simulated set of patient scenarios. Measures of suitability and wearability were applied. The results were encouraging and the system was deemed suitable for further evaluation in the clinical setting, subject to ethical approval
The hyperfine Paschen-Back Faraday effect
We investigate experimentally and theoretically the Faraday effect in an atomic medium in the hyperfine Paschen–Back regime, where the Zeeman interaction is larger than the hyperfine splitting. We use a small permanent magnet and a micro-fabricated vapour cell, giving magnetic fields of the order of a tesla. We show that for low absorption and small rotation angles, the refractive index is well approximated by the Faraday rotation signal, giving a simple way to measure the atomic refractive index. Fitting to the atomic spectra, we achieve magnetic field sensitivity at the 10−4 level. Finally we note that the Faraday signal shows zero crossings which can be used as temperature insensitive error signals for laser frequency stabilization at large detuning. The theoretical sensitivity for 87Rb is found to be ~40 kHz °C−1
Covariance of dark energy parameters and sound speed constraints from large HI surveys
An interesting probe of the nature of dark energy is the measure of its sound
speed, . We review the significance for constraining sound speed models of
dark energy using large neutral hydrogen (HI) surveys with the Square Kilometre
Array (SKA). Our analysis considers the effect on the sound speed measurement
that arises from the covariance of with the dark energy density,
\Omega_\LLambda, and a time-varying equation of state, .
We find that the approximate degeneracy between dark energy parameters that
arises in power spectrum observations is lifted through redshift tomography of
the HI-galaxy angular power spectrum, resulting in sound speed constraints that
are not severely degraded. The cross-correlation of the galaxy and the
integrated Sachs-Wolfe (ISW) effect spectra contributes approximately 10
percent of the information that is needed to distinguish variations in the dark
energy parameters, and most of the discriminating signal comes from the galaxy
auto-correlation spectrum. We also find that the sound speed constraints are
weakly sensitive to the HI bias model. These constraints do not improve
substantially for a significantly deeper HI survey since most of the clustering
sensitivity to sound speed variations arises from z \lsim 1.5. A detection of
models with sound speeds close to zero, c_s \lsim 0.01, is possible for dark
energy models with w\gsim -0.9.Comment: submitted to MNRA
Number counts in homogeneous and inhomogeneous dark energy models
In the simple case of a constant equation of state, redshift distribution of
collapsed structures may constrain dark energy models. Different dark energy
models having the same energy density today but different equations of state
give quite different number counts. Moreover, we show that introducing the
possibility that dark energy collapses with dark matter (``inhomogeneous'' dark
energy) significantly complicates the picture. We illustrate our results by
comparing four dark energy models to the standard -model. We
investigate a model with a constant equation of state equal to -0.8, a phantom
energy model and two scalar potentials (built out of a combination of two
exponential terms). Although their equations of state at present are almost
indistinguishable from a -model, both scalar potentials undergo quite
different evolutions at higher redshifts and give different number counts. We
show that phantom dark energy induces opposite departures from the
-model as compared with the other models considered here. Finally, we
find that inhomogeneous dark energy enhances departures from the
-model with maximum deviations of about 15% for both number counts and
integrated number counts. Larger departures from the -model are
obtained for massive structures which are rare objects making it difficult to
statistically distinguish between models.Comment: 10 pages, 11 figures. Version accepted for publication in A&
Constraining dynamical dark energy with a divergence-free parametrization in the presence of spatial curvature and massive neutrinos
In this paper, we report the results of constraining the dynamical dark
energy with a divergence-free parameterization, , in the presence of spatial curvature and
massive neutrinos, with the 7-yr WMAP temperature and polarization data, the
power spectrum of LRGs derived from SDSS DR7, the Type Ia supernova data from
Union2 sample, and the new measurements of from HST, by using a MCMC
global fit method. Our focus is on the determinations of the spatial curvature,
, and the total mass of neutrinos, , in such a
dynamical dark energy scenario, and the influence of these factors to the
constraints on the dark energy parameters, and . We show that
and can be well constrained in this model; the 95% CL
limits are: and eV. Comparing to
the case in a flat universe, we find that the error in is amplified by
25.51%, and the error in is amplified by 0.14%; comparing to the case
with a zero neutrino mass, we find that the error in is amplified by
12.24%, and the error in is amplified by 1.63%.Comment: 5 pages, 2 figures; discussions added; accepted for publication in
Physics Letters
Phase transitions in Ising magnetic films and superlattices
Within the framework of mean field theory, we examine the phase transitions
in Ising magnetic films and superlattices. By transfer matrix method, we derive
two general nonlinear equations for phase transition temperatures of Ising
magnetic films and superlattices, respectively. The equations can be applied to
the films and superlattices with arbitrary exchange interaction constants and
arbitrary layer number. Numerical results for phase transition temperatures as
a function of exchange interaction constants are presented.Comment: 10 pages, 3 figures, accepted by Solid State Communication
You Watch, You Give, and You Engage: A Study of Live Streaming Practices in China
Despite gaining traction in North America, live streaming has not reached the
popularity it has in China, where livestreaming has a tremendous impact on the
social behaviors of users. To better understand this socio-technological
phenomenon, we conducted a mixed methods study of live streaming practices in
China. We present the results of an online survey of 527 live streaming users,
focusing on their broadcasting or viewing practices and the experiences they
find most engaging. We also interviewed 14 active users to explore their
motivations and experiences. Our data revealed the different categories of
content that was broadcasted and how varying aspects of this content engaged
viewers. We also gained insight into the role reward systems and fan group-chat
play in engaging users, while also finding evidence that both viewers and
streamers desire deeper channels and mechanisms for interaction in addition to
the commenting, gifting, and fan groups that are available today.Comment: Published at ACM CHI Conference on Human Factors in Computing Systems
(CHI 2018). Please cite the CHI versio
Structure and Function of a Mycobacterial NHEJ DNA Repair Polymerase
Non homologous end-joining (NHEJ)-mediated repair of DNA double-strand breaks in prokaryotes requires Ku and a specific multidomain DNA ligase (LigD). We present crystal structures of the primase/polymerisation domain (PolDom) of Mycobacterium tuberculosis LigD, alone and complexed with nucleotides. The PolDom structure combines the general fold of the archaeo-eukaryotic primase (AEP) superfamily with additional loops and domains that together form a deep cleft on the surface, likely used for DNA binding. Enzymatic analysis indicates that the PolDom of LigD, even in the absence of accessory domains and Ku proteins, has the potential to recognise DNA end-joining intermediates. Strikingly, one of the main signals for the specific and efficient binding of PolDom to DNA is the presence of a 5'-phosphate group, located at the single/double-stranded junction at both gapped and 3'-protruding DNA molecules. Although structurally unrelated, Pol lambda and Pol mu, the two eukaryotic DNA polymerases involved in NHEJ, are endowed with a similar capacity to bind a 5'-phosphate group. Other properties that are beneficial for NHEJ, such as the ability to generate template distortions and realignments of the primer, displayed by Pol lambda and Pol mu, are shared by the PolDom of bacterial LigD. In addition, PolDom can perform non-mutagenic translesion synthesis on termini containing modified bases. Significantly, ribonucleotide insertion appears to be a recurrent theme associated with NHEJ, maximised in this case by the deployment of a dedicated primase, although its in vivo relevance is unknown
The effects of neuromuscular electrical stimulation for dysphagia in opercular syndrome: a case study
A 76-year-old man with opercular syndrome characterized by complete bilateral loss of voluntary control of facial, lingual, pharyngeal and masticatory muscles is presented with focus on the severe dysphagia. Three years earlier the patient had experienced two strokes resulting in opercular syndrome with severe dysphagia. Despite initial logopedic dysphagia treatment, swallowing did not improve. A new treatment for dysphagia, consisting of neuromuscular electrical stimulation was applied on the patient. He returned to oral feeding. Clinical and treatment observations are reported
Constraining warm dark matter with cosmic shear power spectra
We investigate potential constraints from cosmic shear on the dark matter
particle mass, assuming all dark matter is made up of light thermal relic
particles. Given the theoretical uncertainties involved in making cosmological
predictions in such warm dark matter scenarios we use analytical fits to linear
warm dark matter power spectra and compare (i) the halo model using a mass
function evaluated from these linear power spectra and (ii) an analytical fit
to the non-linear evolution of the linear power spectra. We optimistically
ignore the competing effect of baryons for this work. We find approach (ii) to
be conservative compared to approach (i). We evaluate cosmological constraints
using these methods, marginalising over four other cosmological parameters.
Using the more conservative method we find that a Euclid-like weak lensing
survey together with constraints from the Planck cosmic microwave background
mission primary anisotropies could achieve a lower limit on the particle mass
of 2.5 keV.Comment: 26 pages, 9 figures, minor changes to match the version accepted for
publication in JCA
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