8,074 research outputs found
An collider based on proton-driven plasma wakefield acceleration
Recent simulations have shown that a high-energy proton bunch can excite
strong plasma wakefields and accelerate a bunch of electrons to the energy
frontier in a single stage of acceleration. This scheme could lead to a future
collider using the LHC for the proton beam and a compact electron
accelerator of length 170 m, producing electrons of energy up to 100 GeV. The
parameters of such a collider are discussed as well as conceptual layouts
within the CERN accelerator complex. The physics of plasma wakefield
acceleration will also be introduced, with the AWAKE experiment, a proof of
principle demonstration of proton-driven plasma wakefield acceleration, briefly
reviewed, as well as the physics possibilities of such an collider.Comment: 6 pages, 2 figures, to appear in the proceedings of the DIS 2014
Workshop, 28 April - 2 May, Warsaw, Polan
Collider design issues based on proton-driven plasma wakefield acceleration
Recent simulations have shown that a high-energy proton bunch can excite
strong plasma wakefields and accelerate a bunch of electrons to the energy
frontier in a single stage of acceleration. It therefore paves the way towards
a compact future collider design using the proton beams from existing
high-energy proton machines, e.g. Tevatron or the LHC. This paper addresses
some key issues in designing a compact electron-positron linear collider and an
electron-proton collider based on existing CERN accelerator infrastructure
Representation of Clients in Matters Relating to Hospital Bills
This article is designed to acquaint Legal Services attorneys with a range of government health programs for which their clients may be eligible, and a number of legal theories that may impose a duty to provide care on public or private medical care institutions. The primary objective is to provide background material to assist the attorney in getting medical bills paid or defending a collection action. The article also includes a discussion of legal duties to provide care that will be useful in advising clients and consumer groups of their rights and of the programs and services that should be available in the community
Representation of Clients in Matters Relating to Hospital Bills
This article is designed to acquaint Legal Services attorneys with a range of government health programs for which their clients may be eligible, and a number of legal theories that may impose a duty to provide care on public or private medical care institutions. The primary objective is to provide background material to assist the attorney in getting medical bills paid or defending a collection action. The article also includes a discussion of legal duties to provide care that will be useful in advising clients and consumer groups of their rights and of the programs and services that should be available in the community
Inferring the Origin Locations of Tweets with Quantitative Confidence
Social Internet content plays an increasingly critical role in many domains,
including public health, disaster management, and politics. However, its
utility is limited by missing geographic information; for example, fewer than
1.6% of Twitter messages (tweets) contain a geotag. We propose a scalable,
content-based approach to estimate the location of tweets using a novel yet
simple variant of gaussian mixture models. Further, because real-world
applications depend on quantified uncertainty for such estimates, we propose
novel metrics of accuracy, precision, and calibration, and we evaluate our
approach accordingly. Experiments on 13 million global, comprehensively
multi-lingual tweets show that our approach yields reliable, well-calibrated
results competitive with previous computationally intensive methods. We also
show that a relatively small number of training data are required for good
estimates (roughly 30,000 tweets) and models are quite time-invariant
(effective on tweets many weeks newer than the training set). Finally, we show
that toponyms and languages with small geographic footprint provide the most
useful location signals.Comment: 14 pages, 6 figures. Version 2: Move mathematics to appendix, 2 new
references, various other presentation improvements. Version 3: Various
presentation improvements, accepted at ACM CSCW 201
Dynamic Boundaries in Asymmetric Exclusion Processes
We investigate the dynamics of a one-dimensional asymmetric exclusion process
with Langmuir kinetics and a fluctuating wall. At the left boundary, particles
are injected onto the lattice; from there, the particles hop to the right.
Along the lattice, particles can adsorb or desorb, and the right boundary is
defined by a wall particle. The confining wall particle has intrinsic forward
and backward hopping, a net leftward drift, and cannot desorb. Performing Monte
Carlo simulations and using a moving-frame finite segment approach coupled to
mean field theory, we find the parameter regimes in which the wall acquires a
steady state position. In other regimes, the wall will either drift to the left
and fall off the lattice at the injection site, or drift indefinitely to the
right. Our results are discussed in the context of non-equilibrium phases of
the system, fluctuating boundary layers, and particle densities in the lab
frame versus the frame of the fluctuating wall.Comment: 13 page
Characterization of slow and fast phase nystagmus
A current literature review of the analog and digital process of vestibular and optical kinetic nystagmus reveals little agreement in the methods used by various labs. The strategies for detection of saccade (fast phase velocity component of nystagmus) vary between labs, and most of the process have not been evaluated and validated with a standard database. A survey was made of major vestibular labs in the U.S. that perform computer analyses of vestibular and optokinetic reflexes to stimuli, and a baseline was established from which to standardize data acquisition and analysis programs. The concept of an Error Index was employed as the criterium for evaluating the performance of the vestibular analysis software programs. The performance criterium is based on the detection of saccades and is the average of the percentages of missed detections and false detections. Evaluation of the programs produced results for lateral gaze with saccadic amplitude of one, two, three, five, and ten degrees with various signal-to-noise ratios. In addition, results were obtained for sinusoidal pursuit of 0.05, 0.10, and 0.50 Hz with saccades from one to ten degrees at various signal-to-noise ratios. Selection of the best program was made from the performance in the lateral gaze with three degrees of saccadic amplitude and in the 0.10 Hz sinusoid with three degrees of saccadic amplitude
Geographic and socioeconomic variation in the onset of decline of coronary heart disease mortality in white women.
BACKGROUND. Regional, metropolitan, and socioeconomic factors related to the onset of decline of coronary heart disease (CHD) mortality among White women are reported. Such studies are important for planning population-level interventions. METHODS. Mortality data for 1962 to 1978 were used, to estimate the year of onset of decline. Ecological analyses of socioeconomic data from the US census were used to emphasize structural and organizational aspects of changes in disease, rather than as a substitute for an individual-level design. RESULTS. Onset of decline of CHD mortality among White women was estimated to have occurred by 1962 in 53% of 507 state economic areas (SEAs), ranging from 79% in the Northeast to 39% in the South. Metropolitan areas experienced earlier onset of decline than did nonmetropolitan areas. Average income, education, and occupational levels were highest in early onset areas and declined across onset categories. CONCLUSIONS. The results provide additional evidence for previously observed geographic and social patterns of CHD decline. Emphasis on structural economic factors determining the shape of the CHD epidemic curve does not detract from the medical importance of risk factors, but underscores the importance of community development to public health improvements. The results are consistent with the idea that the course of the CHD epidemic in the United States has been strongly influenced by socio-economic development
Effect of sensory stimuli on dynamic loading induced by people bouncing
Prediction of dynamic loads induced by groups and crowds of people bouncing is a hot topic among designers of grandstands and floors in entertaining venues. Using motion capture technology transferred and adapted from biomedical research, this study aims to investigate effect of visual, auditory and tactile cues on the ability of people to coordinate or synchronise their bouncing movements in groups of two. The numerical results showed a great significance of such stimuli on people's mutual interaction during bouncing, signifying that their effect should be considered in developing much-needed models of crowd dynamic loading of structures due to coordinated rhythmic activities. © The Society for Experimental Mechanics, Inc. 2013
Detection of H2 pure rotational line emission from the GG~Tau binary system
We present the first detection of the low-lying pure rotational emission
lines of H2 from circumstellar disks around T~Tauri stars, using the Short
Wavelength Spectrometer on the Infrared Space Observatory. These lines provide
a direct measure of the total amount of warm molecular gas in disks. The J=2->0
S(0) line at 28.218 mum and the J=3->1 S(1) line at 17.035 mum have been
observed toward the double binary system GG Tau. Together with limits on the
J=5->3 S(3) and J=7->5 S(5) lines, the data suggest the presence of gas at
T_kin=110+-10 K with a mass of (3.6+-2.0)x10^-3 M_sol (3sigma). This amounts to
~3% of the total gas + dust mass of the circumbinary disk as imaged by
millimeter interferometry, but is larger than the estimated mass of the
circumstellar disk(s). Possible origins for the warm gas seen in H2 are
discussed in terms of photon and wind-shock heating mechanisms of the
circumbinary material, and comparisons with model calculations are made.Comment: 14 pages including 1 figure. To appear in Astrophysical Journal
Letter
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