1,244 research outputs found
Collapse of an Instanton
We construct a two parameter family of collapsing solutions to the 4+1
Yang-Mills equations and derive the dynamical law of the collapse. Our
arguments indicate that this family of solutions is stable. The latter fact is
also supported by numerical simulations.Comment: 17 pages, 1 figur
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Comprehensive Immune Monitoring of Clinical Trials to Advance Human Immunotherapy.
The success of immunotherapy has led to a myriad of clinical trials accompanied by efforts to gain mechanistic insight and identify predictive signatures for personalization. However, many immune monitoring technologies face investigator bias, missing unanticipated cellular responses in limited clinical material. We present here a mass cytometry (CyTOF) workflow for standardized, systems-level biomarker discovery in immunotherapy trials. To broadly enumerate immune cell identity and activity, we established and extensively assessed a reference panel of 33 antibodies to cover major cell subsets, simultaneously quantifying activation and immune checkpoint molecules in a single assay. This assay enumerates ≥98% of peripheral immune cells with ≥4 positively identifying antigens. Robustness and reproducibility are demonstrated on multiple samples types, across two research centers and by orthogonal measurements. Using automated analysis, we identify stratifying immune signatures in bone marrow transplantation-associated graft-versus-host disease. Together, this validated workflow ensures comprehensive immunophenotypic analysis and data comparability and will accelerate biomarker discovery
Resonances Width in Crossed Electric and Magnetic Fields
We study the spectral properties of a charged particle confined to a
two-dimensional plane and submitted to homogeneous magnetic and electric fields
and an impurity potential. We use the method of complex translations to prove
that the life-times of resonances induced by the presence of electric field are
at least Gaussian long as the electric field tends to zero.Comment: 3 figure
Similar antibody responses against SARS-CoV-2 in HIV uninfected and infected individuals on antiretroviral therapy during the first South African infection wave
Keep it SMPL: Automatic Estimation of 3D Human Pose and Shape from a Single Image
We describe the first method to automatically estimate the 3D pose of the
human body as well as its 3D shape from a single unconstrained image. We
estimate a full 3D mesh and show that 2D joints alone carry a surprising amount
of information about body shape. The problem is challenging because of the
complexity of the human body, articulation, occlusion, clothing, lighting, and
the inherent ambiguity in inferring 3D from 2D. To solve this, we first use a
recently published CNN-based method, DeepCut, to predict (bottom-up) the 2D
body joint locations. We then fit (top-down) a recently published statistical
body shape model, called SMPL, to the 2D joints. We do so by minimizing an
objective function that penalizes the error between the projected 3D model
joints and detected 2D joints. Because SMPL captures correlations in human
shape across the population, we are able to robustly fit it to very little
data. We further leverage the 3D model to prevent solutions that cause
interpenetration. We evaluate our method, SMPLify, on the Leeds Sports,
HumanEva, and Human3.6M datasets, showing superior pose accuracy with respect
to the state of the art.Comment: To appear in ECCV 201
The SARS-CoV-2 Delta variant induces an antibody response largely focused on class 1 and 2 antibody epitopes
Short-term mucosal disruption enables colibactin-producing E. coli to cause long-term perturbation of colonic homeostasis
Colibactin, a bacterial genotoxin produced by E. coli strains harboring the pks genomic island, induces cytopathic effects, such as DNA breaks, cell cycle arrest, and apoptosis. Patients with inflammatory bowel diseases, such as ulcerative colitis, display changes in their microbiota with the expansion of E. coli. Whether and how colibactin affects the integrity of the colonic mucosa and whether pks+ E. coli contributes to the pathogenesis of colitis is not clear. Using a gnotobiotic mouse model, we show that under homeostatic conditions, pks+ E. coli do not directly interact with the epithelium or affect colonic integrity. However, upon short-term chemical disruption of mucosal integrity, pks+ E. coli gain direct access to the epithelium, causing epithelial injury and chronic colitis, while mice colonized with an isogenic ΔclbR mutant incapable of producing colibactin show a rapid recovery. pks+ E. coli colonized mice are unable to reestablish a functional barrier. In turn, pks+ E. coli remains in direct contact with the epithelium, perpetuating the process and triggering chronic mucosal inflammation that morphologically and transcriptionally resembles human ulcerative colitis. This state is characterized by impaired epithelial differentiation and high proliferative activity, which is associated with high levels of stromal R-spondin 3. Genetic overexpression of R-spondin 3 in colon myofibroblasts is sufficient to mimic barrier disruption and expansion of E. coli. Together, our data reveal that pks+ E. coli are pathobionts that promote severe injury and initiate a proinflammatory trajectory upon contact with the colonic epithelium, resulting in a chronic impairment of tissue integrity
High-Dimensional Feature Selection by Feature-Wise Kernelized Lasso
The goal of supervised feature selection is to find a subset of input
features that are responsible for predicting output values. The least absolute
shrinkage and selection operator (Lasso) allows computationally efficient
feature selection based on linear dependency between input features and output
values. In this paper, we consider a feature-wise kernelized Lasso for
capturing non-linear input-output dependency. We first show that, with
particular choices of kernel functions, non-redundant features with strong
statistical dependence on output values can be found in terms of kernel-based
independence measures. We then show that the globally optimal solution can be
efficiently computed; this makes the approach scalable to high-dimensional
problems. The effectiveness of the proposed method is demonstrated through
feature selection experiments with thousands of features.Comment: 18 page
Monocular Expressive Body Regression through Body-Driven Attention
To understand how people look, interact, or perform tasks, we need to quickly
and accurately capture their 3D body, face, and hands together from an RGB
image. Most existing methods focus only on parts of the body. A few recent
approaches reconstruct full expressive 3D humans from images using 3D body
models that include the face and hands. These methods are optimization-based
and thus slow, prone to local optima, and require 2D keypoints as input. We
address these limitations by introducing ExPose (EXpressive POse and Shape
rEgression), which directly regresses the body, face, and hands, in SMPL-X
format, from an RGB image. This is a hard problem due to the high
dimensionality of the body and the lack of expressive training data.
Additionally, hands and faces are much smaller than the body, occupying very
few image pixels. This makes hand and face estimation hard when body images are
downscaled for neural networks. We make three main contributions. First, we
account for the lack of training data by curating a dataset of SMPL-X fits on
in-the-wild images. Second, we observe that body estimation localizes the face
and hands reasonably well. We introduce body-driven attention for face and hand
regions in the original image to extract higher-resolution crops that are fed
to dedicated refinement modules. Third, these modules exploit part-specific
knowledge from existing face- and hand-only datasets. ExPose estimates
expressive 3D humans more accurately than existing optimization methods at a
small fraction of the computational cost. Our data, model and code are
available for research at https://expose.is.tue.mpg.de .Comment: Accepted in ECCV'20. Project page: http://expose.is.tue.mpg.d
Local energy decay of massive Dirac fields in the 5D Myers-Perry metric
We consider massive Dirac fields evolving in the exterior region of a
5-dimensional Myers-Perry black hole and study their propagation properties.
Our main result states that the local energy of such fields decays in a weak
sense at late times. We obtain this result in two steps: first, using the
separability of the Dirac equation, we prove the absence of a pure point
spectrum for the corresponding Dirac operator; second, using a new form of the
equation adapted to the local rotations of the black hole, we show by a Mourre
theory argument that the spectrum is absolutely continuous. This leads directly
to our main result.Comment: 40 page
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