381 research outputs found
A Two Energy Gap Preformed-Pair Scenario For the Cuprates: Implications for Angle-Resolved Photoemission Spectroscopy
We show how, within a preformed pair scenario for the cuprate pseudogap, the
nodal and antinodal responses in angle resolved photoemission spectroscopy
necessarily have very different temperature dependences. We examine the
behavior and the contrasting dependences for a range of temperatures both
below and above . Our calculations are based on a fully microscopic
-matrix approach for addressing pairing correlations in a regime where the
attraction is stronger than BCS and the coherence length is anomalously short.
Previously, the distinct nodal and anti-nodal responses have provided strong
support for the "two-gap scenario" of the cuprates in which the pseudogap
competes with superconductivity. Instead, our theory supports a picture in
which the pseudogap derives from pairing correlations, identifying the two gap
components with non-condensed and condensed pairs. It leads to reasonably good
agreement with a range of different experiments in the moderately underdoped
regime and we emphasize that here there is no explicit curve fitting. Ours is a
microscopic rather than a phenomenological theory. We briefly address the more
heavily underdoped regime in which the behavior is more complex.Comment: 12 pages; 10 figure
Multi-Label Image Classification via Knowledge Distillation from Weakly-Supervised Detection
Multi-label image classification is a fundamental but challenging task
towards general visual understanding. Existing methods found the region-level
cues (e.g., features from RoIs) can facilitate multi-label classification.
Nevertheless, such methods usually require laborious object-level annotations
(i.e., object labels and bounding boxes) for effective learning of the
object-level visual features. In this paper, we propose a novel and efficient
deep framework to boost multi-label classification by distilling knowledge from
weakly-supervised detection task without bounding box annotations.
Specifically, given the image-level annotations, (1) we first develop a
weakly-supervised detection (WSD) model, and then (2) construct an end-to-end
multi-label image classification framework augmented by a knowledge
distillation module that guides the classification model by the WSD model
according to the class-level predictions for the whole image and the
object-level visual features for object RoIs. The WSD model is the teacher
model and the classification model is the student model. After this cross-task
knowledge distillation, the performance of the classification model is
significantly improved and the efficiency is maintained since the WSD model can
be safely discarded in the test phase. Extensive experiments on two large-scale
datasets (MS-COCO and NUS-WIDE) show that our framework achieves superior
performances over the state-of-the-art methods on both performance and
efficiency.Comment: accepted by ACM Multimedia 2018, 9 pages, 4 figures, 5 table
Theory of Radio Frequency Spectroscopy Experiments in Ultracold Fermi Gases and Their Relation to Photoemission Experiments in the Cuprates
In this paper we present an overview of radio frequency (RF) spectroscopy in
the atomic Fermi superfluids. An ultimate goal is to suggest new directions in
the cold gas research agenda from the condensed matter perspective.Our focus is
on the experimental and theoretical literature of cold gases and photoemission
spectroscopy of the cuprates particularly as it pertains to areas of overlap.
This paper contains a systematic overview of the theory of RF spectroscopy,
both momentum integrated and momentum resolved. We discuss the effects of
traps, population imbalance, final state interactions over the entire range of
temperatures and compare theory and experiment. We show that this broad range
of phenomena can be accomodated within the BCS-Leggett description of BCS-BEC
crossover and that this scheme also captures some of the central observations
in photoemission experiments in the cuprates. In this last context, we note
that the key themes which have emerged in cuprate photoemission studies involve
characterization of the fermionic self energy, of the pseudogap and of the
effects of superconducting coherence (in passing from above to below the
superfluid transition temperature, ).These issues have a counterpart in
the cold Fermi gases and it would be most useful in future to use these atomic
systems to address these and the more sweeping question of how to describe that
anomalous superfluid phase which forms in the presence of a normal state
excitation gap.Comment: 23 pages, 22 figure
Genetically-Engineered Pig-to-Baboon Liver Xenotransplantation: Histopathology of Xenografts and Native Organs
Orthotopic liver transplantation was carried out in baboons using wild-type (WT, n = 1) or genetically-engineered pigs (α1,3-galactosyltransferase gene-knockout, GTKO), n = 1; GTKO pigs transgenic for human CD46, n = 7) and a clinically-acceptable immunosuppressive regimen. Biopsies were obtained from the WT pig liver pre-Tx and at 30 min, 1, 2, 3, 4 and 5 h post-transplantation. Biopsies of genetically-engineered livers were obtained pre-Tx, 2 h after reperfusion and at necropsy (4–7 days after transplantation). Tissues were examined by light, confocal, and electron microscopy. All major native organs were also examined. The WT pig liver underwent hyperacute rejection. After genetically-engineered pig liver transplantation, hyperacute rejection did not occur. Survival was limited to 4–7 days due to repeated spontaneous bleeding in the liver and native organs (as a result of profound thrombocytopenia) which necessitated euthanasia. At 2 h, graft histology was largely normal. At necropsy, genetically-engineered pig livers showed hemorrhagic necrosis, platelet aggregation, platelet-fibrin thrombi, monocyte/macrophage margination mainly in liver sinusoids, and vascular endothelial cell hypertrophy, confirmed by confocal and electron microscopy. Immunohistochemistry showed minimal deposition of IgM, and almost absence of IgG, C3, C4d, C5b-9, and of a cellular infiltrate, suggesting that neither antibody- nor cell-mediated rejection played a major role
Enabling Cyber Physical Systems with Wireless Sensor Networking Technologies
[[abstract]]Over the last few years, we have witnessed a growing interest in Cyber Physical Systems (CPSs) that rely on a strong synergy between computational and physical components. CPSs are expected to have a tremendous impact on many critical sectors (such as energy, manufacturing, healthcare, transportation, aerospace, etc) of the economy. CPSs have the ability to transform the way human-to-human, human-toobject, and object-to-object interactions take place in the physical and virtual worlds. The increasing pervasiveness of Wireless Sensor Networking (WSN) technologies in many applications make them an important component of emerging CPS designs. We present some of the most important design requirements of CPS architectures. We discuss key sensor network characteristics that can be leveraged in CPS designs. In addition, we also review a few well-known CPS application domains that depend on WSNs in their design architectures and implementations. Finally, we present some of the challenges that still need to be addressed to enable seamless integration of WSN with CPS designs.[[incitationindex]]SCI[[booktype]]ç´™
Rare variants in ANO1, encoding a calcium-activated chloride channel, predispose to moyamoya disease
Moyamoya disease, a cerebrovascular disease leading to strokes in children and young adults, is characterized by progressive occlusion of the distal internal carotid arteries and the formation of collateral vessels. Altered genes play a prominent role in the aetiology of moyamoya disease, but a causative gene is not identified in the majority of cases. Exome sequencing data from 151 individuals from 84 unsolved families were analysed to identify further genes for moyamoya disease, then candidate genes assessed in additional cases (150 probands). Two families had the same rare variant in ANO1, which encodes a calcium-activated chloride channel, anoctamin-1. Haplotype analyses found the families were related, and ANO1 p.Met658Val segregated with moyamoya disease in the family with an LOD score of 3.3. Six additional ANO1 rare variants were identified in moyamoya disease families. The ANO1 rare variants were assessed using patch-clamp recordings, and the majority of variants, including ANO1 p.Met658Val, displayed increased sensitivity to intracellular Ca2+. Patients harbouring these gain-of-function ANO1 variants had classic features of moyamoya disease, but also had aneurysm, stenosis and/or occlusion in the posterior circulation. Our studies support that ANO1 gain-of-function pathogenic variants predispose to moyamoya disease and are associated with unique involvement of the posterior circulation
A mathematical model of the metabolic and perfusion effects on cortical spreading depression
Cortical spreading depression (CSD) is a slow-moving ionic and metabolic
disturbance that propagates in cortical brain tissue. In addition to massive
cellular depolarization, CSD also involves significant changes in perfusion and
metabolism -- aspects of CSD that had not been modeled and are important to
traumatic brain injury, subarachnoid hemorrhage, stroke, and migraine.
In this study, we develop a mathematical model for CSD where we focus on
modeling the features essential to understanding the implications of
neurovascular coupling during CSD. In our model, the sodium-potassium--ATPase,
mainly responsible for ionic homeostasis and active during CSD, operates at a
rate that is dependent on the supply of oxygen. The supply of oxygen is
determined by modeling blood flow through a lumped vascular tree with an
effective local vessel radius that is controlled by the extracellular potassium
concentration. We show that during CSD, the metabolic demands of the cortex
exceed the physiological limits placed on oxygen delivery, regardless of
vascular constriction or dilation. However, vasoconstriction and vasodilation
play important roles in the propagation of CSD and its recovery. Our model
replicates the qualitative and quantitative behavior of CSD --
vasoconstriction, oxygen depletion, extracellular potassium elevation,
prolonged depolarization -- found in experimental studies.
We predict faster, longer duration CSD in vivo than in vitro due to the
contribution of the vasculature. Our results also help explain some of the
variability of CSD between species and even within the same animal. These
results have clinical and translational implications, as they allow for more
precise in vitro, in vivo, and in silico exploration of a phenomenon broadly
relevant to neurological disease.Comment: 17 pages including 9 figures, accepted by PLoS On
Single Nucleotide Polymorphisms of 8 Inflammation-related Genes and their Associations with Smoking-related Cancers
Tobacco smoke and its metabolites are carcinogens that increase tissue oxidative stress and induce target tissue inflammation. We hypothesized that genetic variation of inflammatory pathway genes plays a role in tobacco-related carcinogenesis and is modified by tobacco smoking. We evaluated the association of 12 single nucleotide polymorphisms of 8 inflammation-related genes with tobacco-related cancers (lung, oropharynx, larynx, esophagus, stomach, liver, bladder, and kidney) using 3 case-control studies from: Los Angeles (population-based; 611 lung and 553 upper aero-digestive tract cancer cases and 1,040 controls), Taixing, China (population-based; 218 esophagus, 206 stomach, 204 liver cancer cases, and 415 controls), and Memorial Sloan-Kettering Cancer Center (hospital-based; 227 bladder cancer cases and 211 controls). After adjusting for age, education, ethnicity, gender, and tobacco smoking, IL10 rs1800871 was inversely associated with oropharyngeal cancer (CT+TT vs. CC adjusted odds ratio [aOR]: 0.69, 95% confidence interval [CI]: 0.50-0.95), and was positively associated with lung cancer among never smokers (TT vs. CT+CC aOR: 2.5, 95% CI: 1.3-5.1) and inversely with oropharyngeal cancer among ever smokers (CT+TT vs. CC aOR: 0.63, 95% CI: 0.41-0.95). Among all pooled never smokers (588 cases and 816 controls), TNF rs1799964 was inversely associated with smoking-related cancer (CC vs. CT+TT aOR: 0.36, 95% CI: 0.17-0.77). Bayesian correction for multiple comparisons suggests that chance is unlikely to explain our findings (although epigenetic mechanisms may be in effect), which support our hypotheses, suggesting that IL10 rs1800871 is a susceptibility marker for oropharyngeal and lung cancers, and that TNF rs1799964 is associated with smoking-related cancers among never smokers. © 2010 UICC
Note on Cyclic Sum and Combination Sum of Color-ordered Gluon Amplitudes
Continuing our previous study \cite{Du:2011se} of permutation sum of color
ordered tree amplitudes of gluons, in this note, we prove the large-
behavior of their cyclic sum and the combination of cyclic and permutation sums
under BCFW deformation. Unlike the permutation sum, the study of cyclic sum and
the combination of cyclic and permutation sums is much more difficult. By using
the generalized Bern-Carrasco-Johansson (BCJ) relation, we have proved the
boundary behavior of cyclic sum with nonadjacent BCFW deformation. The proof of
cyclic sum with adjacent BCFW deformation is a little bit simpler, where only
Kleiss-Kuijf (KK) relations are needed. Finally we have presented a new
observation for partial-ordered permutation sum and applied it to prove the
boundary behavior of combination sum with cyclic and permutation.Comment: 21 pages, improved versio
A Complete Developmental Sequence of a Drosophila Neuronal Lineage as Revealed by Twin-Spot MARCM
Labeling every neuron in a lineage in the fruit fly olfactory system reveals that every cell is born with a pre-determined cell fate that is invariant and dependent upon neuron birth orde
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