48 research outputs found
Accelerating model evaluations in uncertainty propagation on tensor grids using computational graph transformations
Methods such as non-intrusive polynomial chaos (NIPC), and stochastic
collocation are frequently used for uncertainty propagation problems.
Particularly for low-dimensional problems, these methods often use a
tensor-product grid for sampling the space of uncertain inputs. A limitation of
this approach is that it encounters a significant challenge: the number of
sample points grows exponentially with the increase of uncertain inputs.
Current strategies to mitigate computational costs abandon the tensor structure
of sampling points, with the aim of reducing their overall count.
Contrastingly, our investigation reveals that preserving the tensor structure
of sample points can offer distinct advantages in specific scenarios. Notably,
by manipulating the computational graph of the targeted model, it is feasible
to avoid redundant evaluations at the operation level to significantly reduce
the model evaluation cost on tensor-grid inputs. This paper presents a
pioneering method: Accelerated Model Evaluations on Tensor grids using
Computational graph transformations (AMTC). The core premise of AMTC lies in
the strategic modification of the computational graph of the target model to
algorithmically remove the repeated evaluations on the operation level. We
implemented the AMTC method within the compiler of a new modeling language
called the Computational System Design Language (CSDL). We demonstrate the
effectiveness of AMTC by using it with the full-grid NIPC method to solve three
low-dimensional UQ problems involving an analytical piston model, a
multidisciplinary unmanned aerial vehicle design model, and a multi-point air
taxi mission analysis model, respectively. For all of the test problems, AMTC
reduces the model evaluation cost by between 50% and 90%, making the full-grid
NIPC the most efficacious method to use among the UQ methods implemented
The Human Phenotype Ontology in 2024: phenotypes around the world.
The Human Phenotype Ontology (HPO) is a widely used resource that comprehensively organizes and defines the phenotypic features of human disease, enabling computational inference and supporting genomic and phenotypic analyses through semantic similarity and machine learning algorithms. The HPO has widespread applications in clinical diagnostics and translational research, including genomic diagnostics, gene-disease discovery, and cohort analytics. In recent years, groups around the world have developed translations of the HPO from English to other languages, and the HPO browser has been internationalized, allowing users to view HPO term labels and in many cases synonyms and definitions in ten languages in addition to English. Since our last report, a total of 2239 new HPO terms and 49235 new HPO annotations were developed, many in collaboration with external groups in the fields of psychiatry, arthrogryposis, immunology and cardiology. The Medical Action Ontology (MAxO) is a new effort to model treatments and other measures taken for clinical management. Finally, the HPO consortium is contributing to efforts to integrate the HPO and the GA4GH Phenopacket Schema into electronic health records (EHRs) with the goal of more standardized and computable integration of rare disease data in EHRs
COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study
Background:
The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms.
Methods:
International, prospective observational study of 60â109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms.
Results:
âTypicalâ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (â€â18 years: 69, 48, 23; 85%), older adults (â„â70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each Pâ<â0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country.
Interpretation:
This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men
Recommended from our members
An SQP algorithm based on a hybrid architecture for accelerating optimization of large-scale systems
Detecting Bacillus cereus spores on a mail sorting system using Raman spectroscopy
The ability of Raman spectroscopy to detect anthrax-causing spores as they pass through a mail sorting system was investigated. A pump was connected to an existing vacuum manifold on a commercial sorter, and a filter designed to capture 0.5-3 Όm particles was placed in-line. A standard business letter containing 0.23 g of Bacillus cereus spores, a Bacillus anthracis surrogate, was placed in a stack of 20 letters and passed through the system. Raman spectra of the filter positively identified the captured material as bacterial spores by the dominant calcium dipicolinate Raman spectral bands associated with the spore core. A limit of detection, using 400 mW of 785 nm laser excitation for a 1-s acquisition, is estimated at 4.5 mg. The ability of a Raman spectroscopy based system to detect and prevent the distribution of a letter containing gram levels of anthrax spores is discussed. © 2004 John Wiley & Sons, Ltd
Carbon Limitation and Drought Sensitivity at Contrasting Elevation and Competition of Abies pinsapo Forests. Does Experimental Thinning Enhance Water Supply and Carbohydrates?
Quantitative characterization of the mechanism of action and impact of a âproteolysis-permittingâ anti-PCSK9 antibody
New Alkaloids from the Mediterranean Sponge Hamigera hamigera
Abstract: The Mediterranean sponge Hamigera hamigera (family Anchinoideae) was studied since its total extract showed deterrent activity in a fish feeding assay. Eight compounds were isolated from the biologically active fractions and four of these proved to be new natural products, hamigeroxalamic acid (1), hamigeramine (2), hamigeramide (3) and hamiguanosinol (5). The structures of the new compounds were elucidated by 1D and 2D NMR spectroscopy and mass spectrometry