7,594 research outputs found
The Higgs Legacy of the LHC Run I
Based on Run I data we present a comprehensive analysis of Higgs couplings.
For the first time this SFitter analysis includes independent tests of the
Higgs-gluon and top Yukawa couplings, Higgs decays to invisible particles, and
off-shell Higgs measurements. The observed Higgs boson is fully consistent with
the Standard Model, both in terms of coupling modifications and effective field
theory. Based only on Higgs total rates the results using both approaches are
essentially equivalent, with the exception of strong correlations in the
parameter space induced by effective operators. These correlations can be
controlled through additional experimental input, namely kinematic
distributions. Including kinematic distributions the typical Run I reach for
weakly interacting new physics now reaches 300 to 500 GeV.Comment: 29 pages, 15 figure
Prejudice Reduction in Public Schools: A Dialogic Approach
Increasingly, students are facing hostility and violence as a result of one or more of their social group memberships. Such prejudicial attitudes and actions contribute to antagonistic intergroup relationships in public schools (i.e., K–12). This article examines dialogic approaches to prejudice reduction, with a specific emphasis on intergroup dialogue in public K–12 schools. Evidence-based steps and strategies that educators can use to develop intergroup dialogue competencies and cultivate a more dialogic environment in their schools and classrooms are also introduced
Theory of frequency-filtered and time-resolved N-photon correlations
A theory of correlations between N photons of given frequencies and detected
at given time delays is presented. These correlation functions are usually too
cumbersome to be computed explicitly. We show that they are obtained exactly
through intensity correlations between two-level sensors in the limit of their
vanishing coupling to the system. This allows the computation of correlation
functions hitherto unreachable. The uncertainties in time and frequency of the
detection, which are necessary variables to describe the system, are intrinsic
to the theory. We illustrate the formalism with the Jaynes--Cummings model,
showing how correlations of various peaks at zero or finite time delays bring
new insights into the dynamics of open quantum systems.Comment: 12 pages, 2 figure
GraphX: Unifying Data-Parallel and Graph-Parallel Analytics
From social networks to language modeling, the growing scale and importance
of graph data has driven the development of numerous new graph-parallel systems
(e.g., Pregel, GraphLab). By restricting the computation that can be expressed
and introducing new techniques to partition and distribute the graph, these
systems can efficiently execute iterative graph algorithms orders of magnitude
faster than more general data-parallel systems. However, the same restrictions
that enable the performance gains also make it difficult to express many of the
important stages in a typical graph-analytics pipeline: constructing the graph,
modifying its structure, or expressing computation that spans multiple graphs.
As a consequence, existing graph analytics pipelines compose graph-parallel and
data-parallel systems using external storage systems, leading to extensive data
movement and complicated programming model.
To address these challenges we introduce GraphX, a distributed graph
computation framework that unifies graph-parallel and data-parallel
computation. GraphX provides a small, core set of graph-parallel operators
expressive enough to implement the Pregel and PowerGraph abstractions, yet
simple enough to be cast in relational algebra. GraphX uses a collection of
query optimization techniques such as automatic join rewrites to efficiently
implement these graph-parallel operators. We evaluate GraphX on real-world
graphs and workloads and demonstrate that GraphX achieves comparable
performance as specialized graph computation systems, while outperforming them
in end-to-end graph pipelines. Moreover, GraphX achieves a balance between
expressiveness, performance, and ease of use
MLI: An API for Distributed Machine Learning
MLI is an Application Programming Interface designed to address the
challenges of building Machine Learn- ing algorithms in a distributed setting
based on data-centric computing. Its primary goal is to simplify the
development of high-performance, scalable, distributed algorithms. Our initial
results show that, relative to existing systems, this interface can be used to
build distributed implementations of a wide variety of common Machine Learning
algorithms with minimal complexity and highly competitive performance and
scalability
Point defect stability in a semicoherent metallic interface
We present a comprehensive density functional theory (DFT) -based study of different aspects of one vacancy and He impurity atom behavior at semicoherent interfaces between the low-solubility transition metals Cu and Nb. Such interfaces have not been previously modeled using DFT. A thorough analysis of the stability and mobility of the two types of defects at the interfaces and neighboring internal layers has been performed and the results have been compared to the equivalent cases in the pure metallic matrices. The different behavior of fcc and bcc metals on both sides of the interface has been specifically assessed. The modeling effort undertaken is the first attempt to study the stability and defect energetics of noncoherent Cu/Nb interfaces from first principles, in order to assess their potential use in radiation-resistant materials.Seventh Framework Programme (European Commission) (Project RAD-INTERFACES)Spain. Ministerio de Economia y Competividad (Project NANO-EXTREM, Ref. MAT2012-38541)United States. Dept. of Energy. Office of Basic Energy Sciences (Award 2008LANL1026
Brachial plexus injury mimicking a spinal-cord injury.
Objective High-energy impact to the head, neck, and shoulder can result in cervical spine as well as brachial plexus injuries. Because cervical spine injuries are more common, this tends to be the initial focus for management. We present a case in which the initial magnetic resonance imaging (MRI) was somewhat misleading and a detailed neurological exam lead to the correct diagnosis.Clinical presentation A 19-year-old man presented to the hospital following a shoulder injury during football practice. The patient immediately complained of significant pain in his neck, shoulder, and right arm and the inability to move his right arm. He was stabilized in the field for a presumed cervical-spine injury and transported to the emergency department.Intervention Initial radiographic assessment (C-spine CT, right shoulder x-ray) showed no bony abnormality. MRI of the cervical-spine showed T2 signal change and cord swelling thought to be consistent with a cord contusion. With adequate pain control, a detailed neurological examination was possible and was consistent with an upper brachial plexus avulsion injury that was confirmed by CT myelogram. The patient failed to make significant neurological recovery and he underwent spinal accessory nerve grafting to the suprascapular nerve to restore shoulder abduction and external rotation, while the phrenic nerve was grafted to the musculocutaneous nerve to restore elbow flexion.Conclusion Cervical spinal-cord injuries and brachial plexus injuries can occur by the same high energy mechanisms and can occur simultaneously. As in this case, MRI findings can be misleading and a detailed physical examination is the key to diagnosis. However, this can be difficult in polytrauma patients with upper extremity injuries, head injuries or concomitant spinal-cord injury. Finally, prompt diagnosis and early surgical renerveration have been associated with better long-term recovery with certain types of injury
- …