1,390 research outputs found
Quantum and string shape fluctuations in the dual Monopole Nambu-Jona-Lasinio model with dual Dirac strings
The magnetic monopole condensate is calculated in the dual Monopole
Nambu-Jona-Lasinio model with dual Dirac strings suggested in Refs.[1,2] as a
functional of the dual Dirac string shape. The calculation is carried out in
the tree approximation in the scalar monopole-antimonopole collective
excitation field. The integration over quantum fluctuations of the dual-vector
monopole-antimonopole collective excitation field around the Abrikosov flux
line and string shape fluctuations are performed explicitly. We claim that
there are important contributions of quantum and string shape fluctuations to
the magnetic monopole condensate.Comment: 19 pages, Latex, 2 figure
Confinement potential in dual Monopole Nambu-Jona-Lasinio model with dual Dirac strings
Interquark confinement potential is calculated in the dual Monopole
Nambu-Jona-Lasinio model with dual Dirac strings as a functional of a dual
Dirac string length. The calculation is carried out by the explicit integration
over quantum fluctuations of a dual-vector field (monopole-antimonopole
collective excitation) around the Abrikosov flux line and string shape
fluctuations. The contribution of the scalar field (monopole-antimonopole
collective excitation) exchange is taken into account in the tree approximation
due to the London limit regime.Comment: 10 pages, Latex, no figure
Successful Cessation Programs that Reduce Comorbidity May Explain Surprisingly Low Smoking Rates Among Hospitalized COVID-19 Patients
A recent, non-peer-reviewed meta-analysis suggests that smoking may reduce the risk of hospitalization with COVID-19 because the prevalence of smoking among hospitalized COVID-19 is less than that of the general population. However, there are alternative explanations for this phenomena based on (1) the failure to report, or accurately record, smoking history during emergency hospital admissions and (2) a pre-disposition to avoid smoking among COVID-19 patients with tobacco-related comorbidities (a type of “reverse” causation). For example, urine testing of hospitalized patients in Australia for cotinine showed that smokers were under-counted by 37% because incoming patients failed to inform staff about their smoking behavior. Face-to-face interviews can introduce bias into the responses to attitudinal and behavioral questions not present in the self-completion interviews typically used to measure smoking prevalence in the general population. Subjects in face-to-face interviews may be unwilling to admit socially undesirable behavior and attitudes under direct questioning. Reverse causation may also contribute to the difference between smoking prevalence in the COVID-19 and general population. Patients hospitalized with COVID-19 may be simply less prone to use tobacco than the general population. A potentially robust “reverse causation” hypothesis for reduced prevalence of smokers in the COVID-19 population is the enrichment of patients in that population with serious comorbidities that motivates them to quit smoking. We judge that this “smoking cessation” mechanism may account for a significant fraction of the reduced prevalence of smokers in the COVID-19 population. Testing this hypothesis will require a focused research program
Verwey transition in FeO at high pressure: quantum critical behavior at the onset of metallization
We provide evidence for the existence of a {\em quantum critical point} at
the metallization of magnetite FeO at an applied pressure of GPa. We show that the present ac magnetic susceptibility data
support earlier resistivity data. The Verwey temperature scales with pressure
, with . The resistivity data shows a
temperature dependence , with above and
2.5 at the critical pressure, respectively. This difference in with
pressure is a sign of critical behavior at . The magnetic susceptibility
is smooth near the critical pressure, both at the Verwey transition and near
the ferroelectric anomaly. A comparison with the critical behavior observed in
the Mott-Hubbard and related systems is made.Comment: 5 pages, 5 figure
Riding against the wind: a review of competition cycling aerodynamics
Aerodynamics has such a profound impact on cycling performance at the elite level that it has infiltrated almost every aspect of the sport from riding position and styles, equipment design and selection, race tactics and training regimes, governing rules and regulations to even the design of new velodromes. This paper presents a review of the aspects of aerodynamics that are critical to understanding flows around cyclists under racing conditions, and the methods used to evaluate and improve aerodynamic performance at the elite level. The fundamental flow physics of bluff body aerodynamics and the mechanisms by which the aerodynamic forces are imparted on cyclists are described. Both experimental and numerical techniques used to investigate cycling aerodynamic performance and the constraints on implementing aerodynamic saving measures at the elite level are also discussed. The review reveals that the nature of cycling flow fields are complex and multi-faceted as a result of the highly three-dimensional and variable geometry of the human form, the unsteady racing environment flow field, and the non-linear interactions that are inherent to all cycling flows. Current findings in this field have and will continue to evolve the sport of elite cycling while also posing a multitude of potentially fruitful areas of research for further gains in cycling performance
BIOVERSE: enhancements to the framework for structural, functional and contextual modeling of proteins and proteomes
We have made a number of enhancements to the previously described Bioverse web server and computational biology framework (). In this update, we provide an overview of the new features available that include: (i) expansion of the number of organisms represented in the Bioverse and addition of new data sources and novel prediction techniques not available elsewhere, including network-based annotation; (ii) reengineering the database backend and supporting code resulting in significant speed, search and ease-of use improvements; and (iii) creation of a stateful and dynamic web application frontend to improve interface speed and usability. Integrated Java-based applications also allow dynamic visualization of real and predicted protein interaction networks
Social brain energetics: ergonomic efficiency, neurometabolic scaling, and metabolic polyphenism in ants
Metabolism, a metric of the energy cost of behavior, plays a significant role in social evolution. Body size and metabolic scaling are coupled, and a socioecological pattern of increased body size is associated with dietary change and the formation of larger and more complex groups. These consequences of the adaptive radiation of animal societies beg questions concerning energy expenses, a substantial portion of which may involve the metabolic rates of brains that process social information. Brain size scales with body size, but little is understood about brain metabolic scaling. Social insects such as ants show wide variation in worker body size and morphology that correlates with brain size, structure, and worker task performance, which is dependent on sensory inputs and information-processing ability to generate behavior. Elevated production and maintenance costs in workers may impose energetic constraints on body size and brain size that are reflected in patterns of metabolic scaling. Models of brain evolution do not clearly predict patterns of brain metabolic scaling, nor do they specify its relationship to task performance and worker ergonomic efficiency, two key elements of social evolution in ants. Brain metabolic rate is rarely recorded and, therefore, the conditions under which brain metabolism influences the evolution of brain size are unclear. We propose that studies of morphological evolution, colony social organization, and worker ergonomic efficiency should be integrated with analyses of species-specific patterns of brain metabolic scaling to advance our understanding of brain evolution in ants.Published versio
Bypass Enhancement RGB Stream Model for Pedestrian Action Recognition of Autonomous Vehicles
Pedestrian action recognition and intention prediction is one of the core
issues in the field of autonomous driving. In this research field, action
recognition is one of the key technologies. A large number of scholars have
done a lot of work to im-prove the accuracy of the algorithm for the task.
However, there are relatively few studies and improvements in the computational
complexity of algorithms and sys-tem real-time. In the autonomous driving
application scenario, the real-time per-formance and ultra-low latency of the
algorithm are extremely important evalua-tion indicators, which are directly
related to the availability and safety of the au-tonomous driving system. To
this end, we construct a bypass enhanced RGB flow model, which combines the
previous two-branch algorithm to extract RGB feature information and optical
flow feature information respectively. In the train-ing phase, the two branches
are merged by distillation method, and the bypass enhancement is combined in
the inference phase to ensure accuracy. The real-time behavior of the behavior
recognition algorithm is significantly improved on the premise that the
accuracy does not decrease. Experiments confirm the superiority and
effectiveness of our algorithm.Comment: Accepted to ACPR 2019 - Workshop on Computer Vision for Modern
Vehicle
An absolute calibration system for millimeter-accuracy APOLLO measurements
Lunar laser ranging provides a number of leading experimental tests of
gravitation -- important in our quest to unify General Relativity and the
Standard Model of physics. The Apache Point Observatory Lunar Laser-ranging
Operation (APOLLO) has for years achieved median range precision at the ~2 mm
level. Yet residuals in model-measurement comparisons are an order-of-magnitude
larger, raising the question of whether the ranging data are not nearly as
accurate as they are precise, or if the models are incomplete or
ill-conditioned. This paper describes a new absolute calibration system (ACS)
intended both as a tool for exposing and eliminating sources of systematic
error, and also as a means to directly calibrate ranging data in-situ. The
system consists of a high-repetition-rate (80 MHz) laser emitting short (< 10
ps) pulses that are locked to a cesium clock. In essence, the ACS delivers
photons to the APOLLO detector at exquisitely well-defined time intervals as a
"truth" input against which APOLLO's timing performance may be judged and
corrected. Preliminary analysis indicates no inaccuracies in APOLLO data beyond
the ~3 mm level, suggesting that historical APOLLO data are of high quality and
motivating continued work on model capabilities. The ACS provides the means to
deliver APOLLO data both accurate and precise below the 2 mm level.Comment: 21 pages, 10 figures, submitted to Classical and Quantum Gravit
The Kondo Dynamics of YbIn(1-x)AgxCu4
We present an infrared/optical study of the dynamics of the strongly
correlated electron system YbIn(1-x)AgxCu4 as a function of doping and
temperature for x ranging from 0 to 1, and T between 20 and 300 K. This study
reveals information about the unusual phase transition as well as the phases
themselves. Scaling relations emerge from the data and are investigated in
detail using a periodic Anderson model based calculation. We also provide a
picture in which to view both the low and high-energy x-dependent features of
the infrared data, including identification of high energy, temperature
dependent features.Comment: 12 pages, 11 figures, submitted Phys. Rev.
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