413 research outputs found
Entanglement Scrambling in 2d Conformal Field Theory
We investigate how entanglement spreads in time-dependent states of a 1+1
dimensional conformal field theory (CFT). The results depend qualitatively on
the value of the central charge. In rational CFTs, which have central charge
below a critical value, entanglement entropy behaves as if correlations were
carried by free quasiparticles. This leads to long-term memory effects, such as
spikes in the mutual information of widely separated regions at late times.
When the central charge is above the critical value, the quasiparticle picture
fails. Assuming no extended symmetry algebra, any theory with has
diminished memory effects compared to the rational models. In holographic CFTs,
with , these memory effects are eliminated altogether at strong
coupling, but reappear after the scrambling time at
weak coupling.Comment: 52 pages, 7 figure; v2: references adde
Holographic Entanglement Entropy from 2d CFT: Heavy States and Local Quenches
We consider the entanglement entropy in 2d conformal field theory in a class
of excited states produced by the insertion of a heavy local operator. These
include both high-energy eigenstates of the Hamiltonian and time-dependent
local quenches. We compute the universal contribution from the stress tensor to
the single interval Renyi entropies and entanglement entropy, and conjecture
that this dominates the answer in theories with a large central charge and a
sparse spectrum of low-dimension operators. The resulting entanglement
entropies agree precisely with holographic calculations in three-dimensional
gravity. High-energy eigenstates are dual to microstates of the BTZ black hole,
so the corresponding holographic calculation is a geodesic length in the black
hole geometry; agreement between these two answers demonstrates that
entanglement entropy thermalizes in individual microstates of holographic CFTs.
For local quenches, the dual geometry is a highly boosted black hole or conical
defect. On the CFT side, the rise in entanglement entropy after a quench is
directly related to the monodromy of a Virasoro conformal block.Comment: 30 pages, 5 figures; v2: minor clarifications and references adde
Lung carcinoma with hypertrophic osteoarthropathy in a teenager
Hypertrophic osteoarthropathy (HOA) characterised by arthralgia, clubbing and periosteal proliferation of long bones, is rarely encountered in children and adolescents. Whereas in adults over 80% of cases are associated with malignancy, in children the majority of cases are due to non-neoplastic causes such as cystic fibrosis, bilary atresia and congenital heart disease. Up to 5% of adults with lung cancer demonstrate signs of HOA. However, lung cancer is extremely uncommon in children and young people. Here we report a case of lung adenocarcinoma in an 18 year old male associated with HOA present both at diagnosis and at subsequent disease progression
Fermi Large Area Telescope Gamma-Ray Detection of the Radio Galaxy M87
We report the Fermi-LAT discovery of high-energy (MeV/GeV) gamma-ray emission
positionally consistent with the center of the radio galaxy M87, at a source
significance of over 10 sigma in ten-months of all-sky survey data. Following
the detections of Cen A and Per A, this makes M87 the third radio galaxy seen
with the LAT. The faint point-like gamma-ray source has a >100 MeV flux of 2.45
(+/- 0.63) x 10^-8 ph cm^-2 s^-1 (photon index = 2.26 +/- 0.13) with no
significant variability detected within the LAT observation. This flux is
comparable with the previous EGRET upper limit (< 2.18 x 10^-8 ph cm^-2 s^-1, 2
sigma), thus there is no evidence for a significant MeV/GeV flare on decade
timescales. Contemporaneous Chandra and VLBA data indicate low activity in the
unresolved X-ray and radio core relative to previous observations, suggesting
M87 is in a quiescent overall level over the first year of Fermi-LAT
observations. The LAT gamma-ray spectrum is modeled as synchrotron self-Compton
(SSC) emission from the electron population producing the radio-to-X-ray
emission in the core. The resultant SSC spectrum extrapolates smoothly from the
LAT band to the historical-minimum TeV emission. Alternative models for the
core and possible contributions from the kiloparsec-scale jet in M87 are
considered, and can not be excluded.Comment: ApJ, accepted, 6 pages, 4 figures. Corresponding authors: C.C.
Cheung, W. McConvill
Crack growth: Does microstructure play a role?
The experimental data presented in this paper reveals that even if the growth of long cracks in two materials, with different microstructures, have different
da/dN
versus
ÎK
curves the corresponding small crack curves can be similar. We also see that long cracks in a large range of steels with different microstructures, chemical compositions, and yield stresses can have similar crack growth rates. The materials science community is challenged to explain these observations. The experimental data also suggests that the threshold term
ÎKthr
in the Hartman-Schijve variant of the NASGRO crack growth equation appears to have the potential to quantify the way in which small cracks interact with the local microstructure. In this context it is also noted that the variability in the life of operational aircraft is controlled by the probability distribution associated with the size and nature of the material discontinuities in the airframe rather than the probability distribution associated with the scatter in the growth of small cracks with a fixed initial size
Genome-wide association study of response to cognitive-behavioural therapy in children with anxiety disorders
Background
Anxiety disorders are common, and cognitiveâbehavioural therapy (CBT) is a first-line treatment. Candidate gene studies have suggested a genetic basis to treatment response, but findings have been inconsistent.
Aims
To perform the first genome-wide association study (GWAS) of psychological treatment response in children with anxiety disorders (n = 980).
Method
Presence and severity of anxiety was assessed using semi-structured interview at baseline, on completion of treatment (post-treatment), and 3 to 12 months after treatment completion (follow-up). DNA was genotyped using the Illumina Human Core Exome-12v1.0 array. Linear mixed models were used to test associations between genetic variants and response (change in symptom severity) immediately post-treatment and at 6-month follow-up.
Results
No variants passed a genome-wide significance threshold (P = 5Ă10â8) in either analysis. Four variants met criteria for suggestive significance (P<5Ă10â6) in association with response post-treatment, and three variants in the 6-month follow-up analysis.
Conclusions
This is the first genome-wide therapygenetic study. It suggests no common variants of very high effect underlie response to CBT. Future investigations should maximise power to detect single-variant and polygenic effects by using larger, more homogeneous cohorts
Four Design Criteria for Any Future Contractarian Theory of Business Ethics
This article assesses the quality of Integrative Social Contracts Theory (ISCT) as a social contract argument. For this purpose, it embarks on a comparative analysis of the use of the social contract model as a theory of political authority and as a theory of social justice. Building on this comparison, it then develops four criteria for any future contractarian theory of business ethics (CBE). To apply the social contract model properly to the domain of business ethics, it should be: (1) self-disciplined, i.e., not aspire results beyond what the contract model can realistically establish; (2) argumentative, i.e., it should seek to provide principles that are demonstrative results of the contractarian method; (3) task-directed, i.e., it should be clear what the social contract thought-experiment is intended to model; and (4) domain-specific, i.e., the contractarian choice situation should be tailored to the defining problems of business ethics
Thrive: Success Strategies for the Modern-Day Faculty Member
The THRIVE collection is intended to help faculty thrive in their roles as educators, scholars, researchers, and clinicians. Each section contains a variety of thought-provoking topics that are designed to be easily digested, guide personal reflection, and put into action. Please use the THRIVE collection to help: Individuals study topics on their own, whenever and wherever they want Peer-mentoring or other learning communities study topics in small groups Leaders and planners strategically insert faculty development into existing meetings
Faculty identify campus experts for additional learning, grand rounds, etc. If you have questions or want additional information on a topic, simply contact the article author or email [email protected]://digitalcommons.unmc.edu/facdev_books/1000/thumbnail.jp
- âŠ