49 research outputs found
Precision-Machine Learning for the Matrix Element Method
The matrix element method is the LHC inference method of choice for limited
statistics. We present a dedicated machine learning framework, based on
efficient phase-space integration, a learned acceptance and transfer function.
It is based on a choice of INN and diffusion networks, and a transformer to
solve jet combinatorics. We showcase this setup for the CP-phase of the top
Yukawa coupling in associated Higgs and single-top production.Comment: 24 pages, 11 figures, v2: update reference
Jet Diffusion versus JetGPT -- Modern Networks for the LHC
We introduce two diffusion models and an autoregressive transformer for LHC
physics simulations. Bayesian versions allow us to control the networks and
capture training uncertainties. After illustrating their different density
estimation methods for simple toy models, we discuss their advantages for Z
plus jets event generation. While diffusion networks excel through their
precision, the transformer scales best with the phase space dimensionality.
Given the different training and evaluation speed, we expect LHC physics to
benefit from dedicated use cases for normalizing flows, diffusion models, and
autoregressive transformers.Comment: 37 pages, 17 figure
Cast aluminium single crystals cross the threshold from bulk to size-dependent stochastic plasticity
Metals are known to exhibit mechanical behaviour at the nanoscale different to bulk samples. This transition typically initiates at the micrometre scale, yet existing techniques to produce micrometre-sized samples often introduce artefacts that can influence deformation mechanisms. Here, we demonstrate the casting of micrometre-scale aluminium single-crystal wires by infiltration of a salt mould. Samples have millimetre lengths, smooth surfaces, a range of crystallographic orientations, and a diameter D as small as 6 μm. The wires deform in bursts, at a stress that increases with decreasing D. Bursts greater than 200 nm account for roughly 50% of wire deformation and have exponentially distributed intensities. Dislocation dynamics simulations show that single-arm sources that produce large displacement bursts halted by stochastic cross-slip and lock formation explain microcast wire behaviour. This microcasting technique may be extended to several other metals or alloys and offers the possibility of exploring mechanical behaviour spanning the micrometre scale
Fig 2B-C.pzfx
Effect of ET-1 on resting pH and NHE activity in HEPES-buffered solution in rat PASMC
Regulation of Smooth Muscle Cell Proliferation by NADPH Oxidases in Pulmonary Hypertension
Hyperproliferation of pulmonary arterial smooth muscle cells is a key component of vascular remodeling in the setting of pulmonary hypertension (PH). Numerous studies have explored factors governing the changes in smooth muscle cell phenotype that lead to the increased wall thickness, and have identified various potential candidates. A role for reactive oxygen species (ROS) has been well documented in PH. ROS can be generated from a variety of sources, including mitochondria, uncoupled nitric oxide synthase, xanthine oxidase, and reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. In this article, we will review recent data supporting a role for ROS generated from NADPH oxidases in promoting pulmonary arterial smooth muscle cell proliferation during PH