1,178 research outputs found
Recommended from our members
Generic sequential sampling for metamodel approximations
Metamodels approximate complex multivariate data sets from simulations and experiments. These data sets often are not based on an explicitly defined function. The resulting metamodel represents a complex system's behavior for subsequent analysis or optimization. Often an exhaustive data search to obtain the data for the metalnodel is impossible, so an intelligent sampling strategy is necessary. While inultiple approaches have been advocated, the majority of these approaches were developed in support of a particular class of metamodel, known as a Kriging. A more generic, cotninonsense approach to this problem allows sequential sampling techniques to be applied to other types of metamodeis. This research compares recent search techniques for Kriging inetamodels with a generic, inulti-criteria approach combined with a new type of B-spline metamodel. This B-spline metamodel is competitive with prior results obtained with a Kriging metamodel. Furthermore, the results of this research highlight several important features necessary for these techniques to be extended to more complex domains
Cold N+NH Collisions in a Magnetic Trap
We present an experimental and theoretical study of atom-molecule collisions
in a mixture of cold, trapped atomic nitrogen and NH molecules at a temperature
of ~mK. We measure a small N+NH trap loss rate coefficient of
~cms.
Accurate quantum scattering calculations based on {\it ab initio} interaction
potentials are in agreement with experiment and indicate the magnetic dipole
interaction to be the dominant loss mechanism. Our theory further indicates the
ratio of N+NH elastic to inelastic collisions remains large () into the
mK regime
Recommended from our members
Magnetic Trapping of Atomic Nitrogen (N) and Cotrapping of NH ( -)
We observe magnetic trapping of atomic nitrogen (N) and cotrapping of ground state imidogen (NH, -). Both are loaded directly from a room temperature beam via buffer gas cooling. We trap approximately 1 x 10 N atoms at a peak density of 5 x 10 cm at 550 mK. The lifetime of atomic nitrogen in the trap is limited by elastic collisions with the helium buffer gas. Cotrapping of N and NH is accomplished, with 10 NH trapped molecules at a peak density of 10 cm.Physic
EXOGEN ultrasound bone healing system for long bone fractures with non-union or delayed healing: a NICE medical technology guidance
Open Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.This article has been made available through the Brunel Open Access Publishing Fund.A routine part of the process for developing National Institute for Health and Care Excellence (NICE) medical technologies guidance is a submission of clinical and economic evidence by the technology manufacturer. The Birmingham and Brunel Consortium External Assessment Centre (EAC; a consortium of the University of Birmingham and Brunel University) independently appraised the submission on the EXOGEN bone healing system for long bone fractures with non-union or delayed healing. This article is an overview of the original evidence submitted, the EAC’s findings, and the final NICE guidance issued.The Birmingham and Brunel Consortium is funded by NICE to act as an External Assessment Centre for the Medical Technologies Evaluation Programme
Cold and Slow Molecular Beam
Employing a two-stage cryogenic buffer gas cell, we produce a cold,
hydrodynamically extracted beam of calcium monohydride molecules with a near
effusive velocity distribution. Beam dynamics, thermalization and slowing are
studied using laser spectroscopy. The key to this hybrid, effusive-like beam
source is a "slowing cell" placed immediately after a hydrodynamic, cryogenic
source [Patterson et al., J. Chem. Phys., 2007, 126, 154307]. The resulting CaH
beams are created in two regimes. One modestly boosted beam has a forward
velocity of vf = 65 m/s, a narrow velocity spread, and a flux of 10^9 molecules
per pulse. The other has the slowest forward velocity of vf = 40 m/s, a
longitudinal temperature of 3.6 K, and a flux of 5x10^8 molecules per pulse
Improving mortality rate estimates for management of the Queensland saucer scallop fishery
This research was undertaken on the Queensland saucer scallop (Ylistrum balloti) fishery in southeast Queensland, which is an important component of the Queensland East Coast Otter Trawl Fishery (QECOTF). The research was undertaken by a collaborative team from the Queensland Department of Agriculture and Fisheries, James Cook University (JCU) and the Centre for Applications in Natural Resource Mathematics (CARM), University of Queensland and focused on 1) an annual fishery-independent trawl survey of scallop abundance, 2) relationships between scallop abundance and physical properties of the seafloor, and 3) deriving an updated estimate of the scallop’s natural mortality rate. The scallop fishery used to be one of the state’s most valuable commercially fished stocks with the annual catch peak at just under 2000 t (adductor muscle meat-weight) in 1993 valued at about $30 million, but in recent years the stock has declined and is currently considered to be overfished. Results from the study are used to improve monitoring, stock assessment and management advice for the fishery
Self-driving Multimodal Studies at User Facilities
Multimodal characterization is commonly required for understanding materials.
User facilities possess the infrastructure to perform these measurements,
albeit in serial over days to months. In this paper, we describe a unified
multimodal measurement of a single sample library at distant instruments,
driven by a concert of distributed agents that use analysis from each modality
to inform the direction of the other in real time. Powered by the Bluesky
project at the National Synchrotron Light Source II, this experiment is a
world's first for beamline science, and provides a blueprint for future
approaches to multimodal and multifidelity experiments at user facilities.Comment: 36th Conference on Neural Information Processing Systems (NeurIPS
2022). AI4Mat Worksho
Behavioral metabolution: the adaptive and evolutionary potential of metabolism-based chemotaxis
We use a minimal model of metabolism-based chemotaxis to show how a coupling between metabolism and behavior can affect evolutionary dynamics in a process we refer to as behavioral metabolution. This mutual influence can function as an in-the-moment, intrinsic evaluation of the adaptive value of a novel situation, such as an encounter with a compound that activates new metabolic pathways. Our model demonstrates how changes to metabolic pathways can lead to improvement of behavioral strategies, and conversely, how behavior can contribute to the exploration and fixation of new metabolic pathways. These examples indicate the potentially important role that the interplay between behavior and metabolism could have played in shaping adaptive evolution in early life and protolife. We argue that the processes illustrated by these models can be interpreted as an unorthodox instantiation of the principles of evolution by random variation and selective retention. We then discuss how the interaction between metabolism and behavior can facilitate evolution through (i) increasing exposure to environmental variation, (ii) making more likely the fixation of some beneficial metabolic pathways, (iii) providing a mechanism for in-the-moment adaptation to changes in the environment and to changes in the organization of the organism itself, and (iv) generating conditions that are conducive to speciatio
HDAC9 is implicated in atherosclerotic aortic calcification and affects vascular smooth muscle cell phenotype.
Aortic calcification is an important independent predictor of future cardiovascular events. We performed a genome-wide association meta-analysis to determine SNPs associated with the extent of abdominal aortic calcification (n = 9,417) or descending thoracic aortic calcification (n = 8,422). Two genetic loci, HDAC9 and RAP1GAP, were associated with abdominal aortic calcification at a genome-wide level (P < 5.0 × 10-8). No SNPs were associated with thoracic aortic calcification at the genome-wide threshold. Increased expression of HDAC9 in human aortic smooth muscle cells promoted calcification and reduced contractility, while inhibition of HDAC9 in human aortic smooth muscle cells inhibited calcification and enhanced cell contractility. In matrix Gla protein-deficient mice, a model of human vascular calcification, mice lacking HDAC9 had a 40% reduction in aortic calcification and improved survival. This translational genomic study identifies the first genetic risk locus associated with calcification of the abdominal aorta and describes a previously unknown role for HDAC9 in the development of vascular calcification
Bycatch weight, composition and preliminary estimates of the impact of bycatch reduction devices in Queensland's trawl fishery
This report provides quantitative information on the effects of turtle excluder devices (TEDs) and bycatch reduction devices (BRDs) on the catch rates of bycatch, prawns, scallops and byproduct species, such as Moreton Bay bugs and Balmain bugs, in Queensland’s major trawl fishing sectors. It also provides biological information on, and management advice for several species referred to in the Fishery Management Plan as the permitted species. Several recommendations are included for reducing bycatch in the trawl fishery and for sustaining stocks of the permitted species
- …