83,567 research outputs found
Transport from the Recycler Ring to the Antiproton Source Beamlines
In the post-Nova era, the protons are directly transported from the Booster
ring to the Recycler ring rather than the Main Injector. For Mu2e and g-2
project, the Debuncher ring will be modified into a Delivery ring to deliver
the protons to both Mu2e and g-2 experiemnts. Therefore, It requires the
transport of protons from the Recycler Ring to the Delivery ring. A new
transfer line from the Recycler ring to the P1 beamline will be constructed to
transport proton beam from the Recycler Ring to existing Antiproton Source
beamlines. This new beamline provides a way to deliver 8 GeV kinetic energy
protons from the Booster to the Delivery ring, via the Recycler, using existing
beam transport lines, and without the need for new civil construction. This
paper presents the Conceptual Design of this new beamline.Comment: 3 pp. 3rd International Particle Accelerator Conference (IPAC 2012)
20-25 May 2012. New Orleans, Louisian
Exact Algorithms for Maximum Independent Set
We show that the maximum independent set problem (MIS) on an -vertex graph
can be solved in time and polynomial space, which even is
faster than Robson's -time exponential-space algorithm
published in 1986. We also obtain improved algorithms for MIS in graphs with
maximum degree 6 and 7, which run in time of and
, respectively. Our algorithms are obtained by using fast
algorithms for MIS in low-degree graphs in a hierarchical way and making a
careful analyses on the structure of bounded-degree graphs
Fuck revisited.
This paper is a follow up to the investigation of McEnery, Baker and Hardie (2000) into the use of the word fuck in spoken British English. Both that paper and this are based on the British National Corpus. However, at the time of writing in 2000, the analysis of fuck in the written BNC had not been completed, hence the 2000 paper focussed on spoken English alone. In doing so, it explored the way fuck varied with respect to a range of meta-data encoded in the spoken BNC, principally age, sex and social class. We have now explored the written section of the BNC, and have explored the distribution of fuck with respect to a subset of the metadata encoded in the written BNC, namely domain, author gender, author age, audience gender, audience age, audience level, reception status, medium of text and date of creation. As some of these features have clear analogues in the spoken BNC (most clearly age and sex) comparisons between the work presented here and the earlier work on spoken English will be presented wherever possible. Throughout, unless otherwise stated, references to the frequency of usage of features in spoken language are taken from McEnery, Baker and Hardie (ibid)
Generic Wavefunction Description of Fractional Quantum Anomalous Hall States and Fractional Topological Insulators
We propose a systematical approach to construct generic fractional quantum
anomalous Hall (FQAH) states, which are generalizations of the fractional
quantum Hall states to lattice models with zero net magnetic field and full
lattice translation symmetry. Local and translationally invariant Hamiltonians
can also be constructed, for which the proposed states are unique ground
states. Our result demonstrates that generic chiral topologically ordered
states can be realized in lattice models, without requiring magnetic
translation symmetry and Landau level structure. We further generalize our
approach to the time-reversal invariant analog of fractional quantum Hall
states--fractional topological insulators, and provide the first explicit
wavefunction description of fractional topological insulators in the absence of
spin conservation.Comment: 4.5 pages, 2 figure
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A Deep Learning Approach to Examine Ischemic ST Changes in Ambulatory ECG Recordings.
Patients with suspected acute coronary syndrome (ACS) are at risk of transient myocardial ischemia (TMI), which could lead to serious morbidity or even mortality. Early detection of myocardial ischemia can reduce damage to heart tissues and improve patient condition. Significant ST change in the electrocardiogram (ECG) is an important marker for detecting myocardial ischemia during the rule-out phase of potential ACS. However, current ECG monitoring software is vastly underused due to excessive false alarms. The present study aims to tackle this problem by combining a novel image-based approach with deep learning techniques to improve the detection accuracy of significant ST depression change. The obtained convolutional neural network (CNN) model yields an average area under the curve (AUC) at 89.6% from an independent testing set. At selected optimal cutoff thresholds, the proposed model yields a mean sensitivity at 84.4% while maintaining specificity at 84.9%
Optimization of electron microscopy for human brains with long-term fixation and fixed-frozen sections.
BackgroundAbnormal connectivity across brain regions underlies many neurological disorders including multiple sclerosis, schizophrenia and autism, possibly due to atypical axonal organization within white matter. Attempts at investigating axonal organization on post-mortem human brains have been hindered by the availability of high-quality, morphologically preserved tissue, particularly for neurodevelopmental disorders such as autism. Brains are generally stored in a fixative for long periods of time (often greater than 10 years) and in many cases, already frozen and sectioned on a microtome for histology and immunohistochemistry. Here we present a method to assess the quality and quantity of axons from long-term fixed and frozen-sectioned human brain samples to demonstrate their use for electron microscopy (EM) measures of axonal ultrastructure.ResultsSix samples were collected from white matter below the superior temporal cortex of three typically developing human brains and prepared for EM analyses. Five samples were stored in fixative for over 10 years, two of which were also flash frozen and sectioned on a freezing microtome, and one additional case was fixed for 3 years and sectioned on a freezing microtome. In all six samples, ultrastructural qualitative and quantitative analyses demonstrate that myelinated axons can be identified and counted on the EM images. Although axon density differed between brains, axonal ultrastructure and density was well preserved and did not differ within cases for fixed and frozen tissue. There was no significant difference between cases in axon myelin sheath thickness (g-ratio) or axon diameter; approximately 70% of axons were in the small (0.25 μm) to medium (0.75 μm) range. Axon diameter and g-ratio were positively correlated, indicating that larger axons may have thinner myelin sheaths.ConclusionThe current study demonstrates that long term formalin fixed and frozen-sectioned human brain tissue can be used for ultrastructural analyses. Axon integrity is well preserved and can be quantified using the methods presented here. The ability to carry out EM on frozen sections allows for investigation of axonal organization in conjunction with other cellular and histological methods, such as immunohistochemistry and stereology, within the same brain and even within the same frozen cut section
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