4,309 research outputs found
Market Developments on Chinese International Air Passenger Markets in Light of COVID-19 Policy Measures
The worldâs governments imposed a plethora of restrictions and quarantine rules to prevent the rapid spread of COVID-19. China was chosen for this study as it was the first market
to be impacted. The overall aim of this paper was to analyse international air travel to and from China since the start of COVID-19 and to assess the impact of policy initiatives on seat capacity during this time. The key findings are that implementation of the so called Five one policy in March
2020 was associated with an almost immediate reduction in seat capacity on China to the rest of the world, partially suppressing the more typical impact of underlying GDP and air fares on capacity. It was further found that Chinese international gateways, as airports with substantial proportions of international and connecting traffic, remain the most distressed. Long haul international traffic and revenues from European and North American destinations all experienced unprecedented and sharp reductions. Traffic and revenues from other Asian markets was even more sporadic. Alarmingly, the study extracted that revenues from premium classes were deteriorating much faster than economy
class, which is of imminent concern for long-haul carriers reliant on premium traffic coming into the pandemic
Charged-current neutrino-208Pb reactions
We present theoretical results on the non flux-averaged
and
reaction cross sections, obtained within the charge-exchange
Random-Phase-Approximation. A detailed knowledge of these cross sections is
important in different contexts. In particular, it is necessary to assess the
possibility of using lead as a detector in future experiments on supernova
neutrinos, such as OMNIS and LAND, and eventually detect neutrino oscillation
signals by exploiting the spectroscopic properties of . We discuss
the present status on the theoretical predictions of the reaction cross
sections.Comment: 5 pages, latex, 3 figures. added discussion on present status,
Submitted to Phys.Rev.
The angular distribution of the reaction
The reaction is very important for low-energy
( MeV) antineutrino experiments. In this paper we calculate
the positron angular distribution, which at low energies is slightly backward.
We show that weak magnetism and recoil corrections have a large effect on the
angular distribution, making it isotropic at about 15 MeV and slightly forward
at higher energies. We also show that the behavior of the cross section and the
angular distribution can be well-understood analytically for MeV by calculating to , where is the nucleon mass. The
correct angular distribution is useful for separating events from other reactions and detector backgrounds, as well as for
possible localization of the source (e.g., a supernova) direction. We comment
on how similar corrections appear for the lepton angular distributions in the
deuteron breakup reactions and . Finally, in the reaction , the
angular distribution of the outgoing neutrons is strongly forward-peaked,
leading to a measurable separation in positron and neutron detection points,
also potentially useful for rejecting backgrounds or locating the source
direction.Comment: 10 pages, including 5 figure
Surface Roughness and Effective Stick-Slip Motion
The effect of random surface roughness on hydrodynamics of viscous
incompressible liquid is discussed. Roughness-driven contributions to
hydrodynamic flows, energy dissipation, and friction force are calculated in a
wide range of parameters. When the hydrodynamic decay length (the viscous wave
penetration depth) is larger than the size of random surface inhomogeneities,
it is possible to replace a random rough surface by effective stick-slip
boundary conditions on a flat surface with two constants: the stick-slip length
and the renormalization of viscosity near the boundary. The stick-slip length
and the renormalization coefficient are expressed explicitly via the
correlation function of random surface inhomogeneities. The effective
stick-slip length is always negative signifying the effective slow-down of the
hydrodynamic flows by the rough surface (stick rather than slip motion). A
simple hydrodynamic model is presented as an illustration of these general
hydrodynamic results. The effective boundary parameters are analyzed
numerically for Gaussian, power-law and exponentially decaying correlators with
various indices. The maximum on the frequency dependence of the dissipation
allows one to extract the correlation radius (characteristic size) of the
surface inhomogeneities directly from, for example, experiments with torsional
quartz oscillators.Comment: RevTeX4, 14 pages, 3 figure
The influence of Îœh11/2 occupancy on the magnetic moments of collective 21+ states in AâŒ100 fission fragments
AbstractThe magnetic moments of IÏ=21+ states in evenâeven AâŒ100 fission fragments have been measured using the Gammasphere array, using the technique of time-integral perturbed angular correlations. The data are interpreted within the context of the interacting boson model (IBA2) leading to the suggestion of a strong Îœh11/2 component in the deformed 21+ states of this region
Application of Pulsed Field Gel Electrophoresis to Determine Îł-ray-induced Double-strand Breaks in Yeast Chromosomal Molecules
The frequency of DNA double-strand breaks (dsb) was determined in yeast cells exposed to Îł-rays under anoxic conditions. Genomic DNA of treated cells was separated by pulsed field gel electrophoresis, and two different approaches for the evaluation of the gels were employed: (1) The DNA mass distribution profile obtained by electrophoresis was compared to computed profiles, and the number of DSB per unit length was then derived in terms of a fitting procedure; (2) hybridization of selected chromosomes was performed, and a comparison of the hybridization signals in treated and untreated samples was then used to derive the frequency of dsb
Pharmacist insights into adolescent human papillomavirus vaccination provision in the United States
HPV vaccination coverage in the United States (US) falls short of the Healthy People 2020 goal of 80% coverage among 13â15 year-old adolescents. Pharmacies are a promising alternative vaccine delivery site that may increase access to HPV vaccination. Our objective was to assess pharmacistsâ insights into HPV vaccination provision to adolescents. We recruited 40 licensed pharmacists in eight states with different pharmacy vaccination laws: Alabama, California, Indiana, Kentucky, Maine, Tennessee, Texas, and Washington. Eligible pharmacists either previously provided or were currently providing HPV, tetanus-diphtheria-pertussis, or meningococcal vaccines to adolescents aged 9â17 years. Pharmacists were administered a semi-structured survey to explore insights into HPV vaccination provision. Forty-five percent of surveyed pharmacies offered HPV vaccination to adolescents. Pharmacistsâ reported challenges to providing HPV vaccination were parental consent (28%), tracking and patient recall (17%), perceived stigma of vaccination (17%), and education about or promotion of vaccination (17%). Pharmacists offering HPV vaccination sent patient reminders for vaccines with multiple doses (89%) and utilized telephone reminders (72%). Pharmacists informed patientsâ primary care providers of HPV vaccination doses most commonly through fax (72%) and updating electronic medical records (22%). One-third of pharmacists reported vaccination provision using the state immunization information system (IIS). Seventy-five percent reported vaccination rates could be increased at their respective pharmacy. Pharmacies are underutilized, although highly accessible, for HPV vaccination in the US. National efforts should expand educational programs to improve public awareness of in-pharmacy HPV vaccination, and improve the utilization of state IIS for reporting immunization coverage of adolescents by pharmacists
Modeling DNA Structure, Elasticity and Deformations at the Base-pair Level
We present a generic model for DNA at the base-pair level. We use a variant
of the Gay-Berne potential to represent the stacking energy between neighboring
base-pairs. The sugar-phosphate backbones are taken into account by semi-rigid
harmonic springs with a non-zero spring length. The competition of these two
interactions and the introduction of a simple geometrical constraint leads to a
stacked right-handed B-DNA-like conformation. The mapping of the presented
model to the Marko-Siggia and the Stack-of-Plates model enables us to optimize
the free model parameters so as to reproduce the experimentally known
observables such as persistence lengths, mean and mean squared base-pair step
parameters. For the optimized model parameters we measured the critical force
where the transition from B- to S-DNA occurs to be approximately . We
observe an overstretched S-DNA conformation with highly inclined bases that
partially preserves the stacking of successive base-pairs.Comment: 15 pages, 25 figures. submitted to PR
Fluctuating Filaments I: Statistical Mechanics of Helices
We examine the effects of thermal fluctuations on thin elastic filaments with
non-circular cross-section and arbitrary spontaneous curvature and torsion.
Analytical expressions for orientational correlation functions and for the
persistence length of helices are derived, and it is found that this length
varies non-monotonically with the strength of thermal fluctuations. In the weak
fluctuation regime, the local helical structure is preserved and the
statistical properties are dominated by long wavelength bending and torsion
modes. As the amplitude of fluctuations is increased, the helix ``melts'' and
all memory of intrinsic helical structure is lost. Spontaneous twist of the
cross--section leads to resonant dependence of the persistence length on the
twist rate.Comment: 5 figure
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