7,772 research outputs found
On central tendency and dispersion measures for intervals and hypercubes
The uncertainty or the variability of the data may be treated by considering,
rather than a single value for each data, the interval of values in which it
may fall. This paper studies the derivation of basic description statistics for
interval-valued datasets. We propose a geometrical approach in the
determination of summary statistics (central tendency and dispersion measures)
for interval-valued variables
Chiral Gauge Theory on Lattice with Domain Wall Fermions
We investigate a U(1) lattice chiral gauge theory with domain wall fermions
and compact gauge fixing. In the reduced model limit, our perturbative and
numerical investigations show that there exist no extra mirror chiral modes.
The longitudinal gauge degrees of freedom have no effect on the free domain
wall fermion spectrum consisting of opposite chiral modes at the domain wall
and at the anti-domain wall which have an exponentially damped overlap.Comment: 16 pages revtex, 5 postscript figures, PRD versio
Computing Inferences for Large-Scale Continuous-Time Markov Chains by Combining Lumping with Imprecision
If the state space of a homogeneous continuous-time Markov chain is too
large, making inferences - here limited to determining marginal or limit
expectations - becomes computationally infeasible. Fortunately, the state space
of such a chain is usually too detailed for the inferences we are interested
in, in the sense that a less detailed - smaller - state space suffices to
unambiguously formalise the inference. However, in general this so-called
lumped state space inhibits computing exact inferences because the
corresponding dynamics are unknown and/or intractable to obtain. We address
this issue by considering an imprecise continuous-time Markov chain. In this
way, we are able to provide guaranteed lower and upper bounds for the
inferences of interest, without suffering from the curse of dimensionality.Comment: 9th International Conference on Soft Methods in Probability and
Statistics (SMPS 2018
Observations of [C II] 158 micron Line and Far-infrared Continuum Emission toward the High-latitude Molecular Clouds in Ursa Major
We report the results of a rocket-borne observation of [C II] 158\micron line
and far-infrared continuum emission at 152.5\micron toward the high latitude
molecular clouds in Ursa Major. We also present the results of a follow-up
observation of the millimeter ^{12}CO J=1-0 line over a selected region
observed by the rocket-borne experiment. We have discovered three small CO
cloudlets from the follow-up ^{12}CO observations. We show that these molecular
cloudlets, as well as the MBM clouds(MBM 27/28/29/30), are not gravitationally
bound. Magnetic pressure and turbulent pressure dominate the dynamic balance of
the clouds. After removing the HI-correlated and background contributions, we
find that the [C II] emission peak is displaced from the 152.5\micron and CO
peaks, while the 152.5\micron continuum emission is spatially correlated with
the CO emission. We interpret this behavior by attributing the origin of [C II]
emission to the photodissociation regions around the molecular clouds
illuminated by the local UV radiation field. We also find that the ratio of the
molecular hydrogen column density to velocity-integrated CO intensity is
1.19+-0.29x10^{20} cm^{-2} (K kms^{-1})^{-1} from the FIR continuum and the CO
data. The average [C II] /FIR intensity ratio over the MBM clouds is 0.0071,
which is close to the all sky average of 0.0082 reported by the FIRAS on the
COBE satellite. The average [C II]/CO ratio over the same regions is 420, which
is significantly lower than that of molecular clouds in the Galactic plane.Comment: 15 pages, LaTeX (aaspp4.sty) + 2 tables(apjpt4.sty) + 6 postscript
figures; accepted for publication in the Astrophysical Journal; Astrophys. J.
in press (Vol. 490, December 1, 1997 issue
Spontaneous symmetry breaking on the lattice generated by Yukawa interaction
We study by numerical simulation a lattice Yukawa model with naive fermions
at intermediate values of the Yukawa coupling when the nearest neighbour
coupling \kp of the scalar field is very weakly ferromagnetic (\kp
\approx 0) or even antiferromagnetic () and the nonvanishing value
of \vev is generated by the Yukawa interaction. The renormalized Yukawa
coupling achieves here its maximal value and this -region is thus of
particular importance for lattice investigations of strong Yukawa interaction.
However, here the scalar field propagators have a very complex structure caused
by fermion loop corrections and by the proximity of phases with
antiferromagnetic properties. We develop methods for analyzing these
propagators and for extracting the physical observables. We find that going
into the negative \kp region, the scalar field renormalization constant
becomes small and does not seem to exceed the unitarity bound, making the
existence of a nontrivial fixed point in the investigated Yukawa model quite
unlikely.Comment: 22 pages plus 13 figure
Lattice Chiral Fermions
I review the ongoing attempts to define chiral gauge theories using the
lattice regularization.Comment: Plenary talk at Lattice'95, Melbourne, Australia. LaTeX, 16 page
MAXIPOL: Cosmic Microwave Background Polarimetry Using a Rotating Half-Wave Plate
We discuss MAXIPOL, a bolometric balloon-borne experiment designed to measure
the E-mode polarization of the cosmic microwave background radiation (CMB).
MAXIPOL is the first bolometric CMB experiment to observe the sky using rapid
polarization modulation. To build MAXIPOL, the CMB temperature anisotropy
experiment MAXIMA was retrofitted with a rotating half-wave plate and a
stationary analyzer. We describe the instrument, the observations, the
calibration and the reduction of data collected with twelve polarimeters
operating at 140 GHz and with a FWHM beam size of 10 arcmin. We present maps of
the Q and U Stokes parameters of an 8 deg^2 region of the sky near the star
Beta Ursae Minoris. The power spectra computed from these maps give weak
evidence for an EE signal. The maximum-likelihood amplitude of
l(l+1)C^{EE}_{l}/(2 pi) is 55_{-45}^{+51} uK^2 (68%), and the likelihood
function is asymmetric and skewed positive such that with a uniform prior the
probability that the amplitude is positive is 96%. This result is consistent
with the expected concordance LCDM amplitude of 14 uK^2. The maximum likelihood
amplitudes for l(l+1)C^{BB}_{l}/(2 pi) and are
-31_{-19}^{+31} and 18_{-34}^{+27} uK^2 (68%), respectively, which are
consistent with zero. All of the results are for one bin in the range 151 < l <
693. Tests revealed no residual systematic errors in the time or map domain. A
comprehensive discussion of the analysis of the data is presented in a
companion paper.Comment: 19 pages, 11 figures, 2 tables, submitted to Ap
Liquid state properties from first principles DFT calculations: Static properties
In order to test the Vibration-Transit (V-T) theory of liquid dynamics, ab
initio density functional theory (DFT) calculations of thermodynamic properties
of Na and Cu are performed and compared with experimental data. The
calculations are done for the crystal at T = 0 and T_m, and for the liquid at
T_m. The key theoretical quantities for crystal and liquid are the structural
potential and the dynamical matrix, both as function of volume. The theoretical
equations are presented, as well as details of the DFT computations. The
properties compared with experiment are the equilibrium volume, the isothermal
bulk modulus, the internal energy and the entropy. The agreement of theory with
experiment is uniformly good. Our primary conclusion is that the application of
DFT to V-T theory is feasible, and the resulting liquid calculations achieve
the same level of accuracy as does ab initio lattice dynamics for crystals.
Moreover, given the well established reliability of DFT, the present results
provide a significant confirmation of V-T theory itself.Comment: 9 pages, 3 figures, 5 tables, edited to more closely match published
versio
Feasibility of Perioperative eHealth Interventions for Older Surgical Patients:A Systematic Review
OBJECTIVES: EHealth interventions are increasingly being applied in perioperative care but have not been adequately studied for older surgical patients who could potentially benefit from them. Therefore, we evaluated the feasibility of perioperative eHealth interventions for this population. DESIGN: A systematic review of prospective observational and interventional studies was conducted. Three electronic databases (PubMed, EMBASE, CINAHL) were searched between January 1999 and July 2019. Study quality was assessed by Methodological Index for Non-Randomized Studies (MINORS) with and without control group. SETTING AND PARTICIPANTS: Studies of surgical patients with an average age â„65 years undergoing any perioperative eHealth intervention with active patient participation (with the exception of telerehabilitation following orthopedic surgery) were included. MEASURES: The main outcome measure was feasibility, defined as a patient's perceptions of usability, satisfaction, and/or acceptability of the intervention. Other outcomes included compliance and study completion rate. RESULTS: Screening of 1569 titles and abstracts yielded 7 single-center prospective studies with 223 patients (range n = 9-69 per study, average age 66-74 years) undergoing oncological, cardiovascular, or orthopedic surgery. The median MINORS scores were 13.5 of 16 for 6 studies without control group, and 14 of 24 for 1 study with a control group. Telemonitoring interventions were rated as "easy to use" by 89% to 95% of participants in 3 studies. Patients in 3 studies were satisfied with the eHealth intervention and would recommend it to others. Acceptability (derived from consent rate) ranged from 71% to 89%, compliance from 53% to 86%, and completion of study follow-up from 54% to 95%. CONCLUSIONS AND IMPLICATIONS: Results of 7 studies involving perioperative eHealth interventions suggest their feasibility and encourage further development of technologies for older surgical patients. Future feasibility studies require clear definitions of appropriate feasibility outcome measures and a comprehensive description of patient characteristics such as functional performance, level of education, and socioeconomic status
- âŠ