38 results match your criteria: "Isaac Newton Institute for Mathematical Sciences[Affiliation]"

Controlling wall-particle interactions with activity.

Soft Matter

October 2024

School of Mathematics, University of Bristol, Fry Building, Bristol BS8 1UG, UK.

We theoretically determine the effective forces on hard disks near walls embedded inside active nematic liquid crystals. When the disks are sufficiently close to the wall and the flows are sufficiently slow, we can obtain exact expressions for the effective forces. We find these forces and the dynamics of disks near the wall depend both on the properties of the active nematic and on the anchoring conditions on the disks and the wall.

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Article Synopsis
  • Wound healing involves a process called re-epithelialisation where cells help to close up a cut in the skin.
  • Scientists studied this process in fruit flies (Drosophila), using videos and deep learning technology to see how different cell behaviors like moving, changing shape, and dividing help with healing.
  • They found that certain signals in the cells, like Ca2+ and JNK, play specific roles in how cells behave during healing, showing that deep learning can help us understand how wounds heal better.
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Field Theory for Mechanical Criticality in Disordered Fiber Networks.

Phys Rev Lett

July 2024

Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA.

Strain-controlled criticality governs the elasticity of jamming and fiber networks. While the upper critical dimension of jamming is believed to be d_{u}=2, non-mean-field exponents are observed in numerical studies of 2D and 3D fiber networks. The origins of this remains unclear.

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Spatial transcriptomics measures in situ gene expression at millions of locations within a tissue, hitherto with some trade-off between transcriptome depth, spatial resolution and sample size. Although integration of image-based segmentation has enabled impactful work in this context, it is limited by imaging quality and tissue heterogeneity. By contrast, recent array-based technologies offer the ability to measure the entire transcriptome at subcellular resolution across large samples.

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Elliptic PDE learning is provably data-efficient.

Proc Natl Acad Sci U S A

September 2023

Mathematics Department, Cornell University, Ithaca, NY 14853-4201.

Partial differential equations (PDE) learning is an emerging field that combines physics and machine learning to recover unknown physical systems from experimental data. While deep learning models traditionally require copious amounts of training data, recent PDE learning techniques achieve spectacular results with limited data availability. Still, these results are empirical.

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The purpose of this review was to identify the effectiveness of environmental control (EC) non-pharmaceutical interventions (NPIs) in reducing transmission of SARS-CoV-2 through conducting a systematic review. EC NPIs considered in this review are room ventilation, air filtration/cleaning, room occupancy, surface disinfection, barrier devices, [Formula: see text] monitoring and one-way-systems. Systematic searches of databases from Web of Science, Medline, EMBASE, preprint servers MedRxiv and BioRxiv were conducted in order to identify studies reported between 1 January 2020 and 1 December 2022.

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Quantification and classification of protein structures, such as knotted proteins, often requires noise-free and complete data. Here, we develop a mathematical pipeline that systematically analyses protein structures. We showcase this geometric framework on proteins forming open-ended trefoil knots, and we demonstrate that the mathematical tool, persistent homology, faithfully represents their structural homology.

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Preface: Challenges for future pandemics.

Epidemics

September 2022

Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, UK. Electronic address:

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COVID-19 has shown that the consequences of a pandemic are wider-reaching than cases and deaths. Morbidity and mortality are important direct costs, but infectious diseases generate other direct and indirect benefits and costs as the economy responds to these shocks: some people lose, others gain and people modify their behaviours in ways that redistribute these benefits and costs. These additional effects feedback on health outcomes to create a complicated interdependent system of health and non-health outcomes.

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This paper reviews the modern state of the Wiener-Hopf factorization method and its generalizations. The main constructive results for matrix Wiener-Hopf problems are presented, approximate methods are outlined and the main areas of applications are mentioned. The aim of the paper is to offer an overview of the development of this method, and demonstrate the importance of bringing together pure and applied analysis to effectively employ the Wiener-Hopf technique.

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A proof that multiple waves propagate in ensemble-averaged particulate materials.

Proc Math Phys Eng Sci

September 2019

School of Mathematics, University of Manchester, Oxford Road, Manchester M13 9PL, UK.

Effective medium theory aims to describe a complex inhomogeneous material in terms of a few important macroscopic parameters. To characterize wave propagation through an inhomogeneous material, the most crucial parameter is the . For this reason, there are many published studies on how to calculate a single effective wavenumber.

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We combine state-of-the art synthesis, simulations, and physical experiments to explore the tunable, responsive character of telechelic star polymers as models for soft patchy particles. We focus on the simplest possible system: a star comprising three asymmetric block copolymer arms with solvophilic inner and solvophobic outer blocks. Our dilute solution studies reveal the onset of a second slow mode in the intermediate scattering functions as the temperature decreases below the θ-point of the outer block, as well as the size reduction of single stars upon further decreasing temperature.

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Many biological molecules exist in multiple variants, such as proteins with different posttranslational modifications, DNAs with different sequences, and phospholipids with different chain lengths. Representing these variants as distinct species, as most biochemical simulators do, leads to the problem that the number of species, and chemical reactions that interconvert them, typically increase combinatorially with the number of ways that the molecules can vary. This can be alleviated by "rule-based modeling methods," in which software generates the chemical reaction network from relatively simple "rules.

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We formally deduce closed-form expressions for the transmitted effective wavenumber of a material comprising multiple types of inclusions or particles (multi-species), dispersed in a uniform background medium. The expressions, derived here for the first time, are valid for moderate volume fractions and without restriction on the frequency. We show that the multi-species effective wavenumber is not a straightforward extension of expressions for a single species.

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Avoiding overstating the strength of forensic evidence: Shrunk likelihood ratios/Bayes factors.

Sci Justice

May 2018

Department of Computer Science, University of Surrey, Guildford, England, United Kingdom; QuintilesIMS, London, England, United Kingdom.

When strength of forensic evidence is quantified using sample data and statistical models, a concern may be raised as to whether the output of a model overestimates the strength of evidence. This is particularly the case when the amount of sample data is small, and hence sampling variability is high. This concern is related to concern about precision.

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Score based procedures for the calculation of forensic likelihood ratios are popular across different branches of forensic science. They have two stages, first a function or model which takes measured features from known-source and questioned-source pairs as input and calculates scores as output, then a subsequent model which converts scores to likelihood ratios. We demonstrate that scores which are purely measures of similarity are not appropriate for calculating forensically interpretable likelihood ratios.

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What should a forensic practitioner's likelihood ratio be? II.

Sci Justice

November 2017

Forensic Speech Science Laboratory, Centre for Forensic Linguistics, Aston University, Birmingham, England, United Kingdom; Department of Linguistics, University of Alberta, Edmonton, Alberta, Canada; Isaac Newton Institute for Mathematical Sciences, Cambridge, England, United Kingdom. Electronic address:

In the debate as to whether forensic practitioners should assess and report the precision of the strength of evidence statements that they report to the courts, I remain unconvinced by proponents of the position that only a subjectivist concept of probability is legitimate. I consider this position counterproductive for the goal of having forensic practitioners implement, and courts not only accept but demand, logically correct and scientifically valid evaluation of forensic evidence. In considering what would be the best approach for evaluating strength of evidence, I suggest that the desiderata be (1) to maximise empirically demonstrable performance; (2) to maximise objectivity in the sense of maximising transparency and replicability, and minimising the potential for cognitive bias; and (3) to constrain and make overt the forensic practitioner's subjective-judgement based decisions so that the appropriateness of those decisions can be debated before the judge in an admissibility hearing and/or before the trier of fact at trial.

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Motivation: Smoldyn is a spatial and stochastic biochemical simulator. It treats each molecule of interest as an individual particle in continuous space, simulating molecular diffusion, molecule-membrane interactions and chemical reactions, all with good accuracy. This article presents several new features.

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Structure-based engineering of a pectate lyase with improved specific activity for ramie degumming.

Appl Microbiol Biotechnol

April 2017

National Engineering Laboratory for Industrial Enzymes and Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.

Biotechnological applications of microbial pectate lyases (Pels) in plant fiber processing are promising, eco-friendly substitutes for conventional chemical degumming processes. However, to potentiate the enzymes' use for industrial applications, resolving the molecular structure to elucidate catalytic mechanisms becomes necessary. In this manuscript, we report the high resolution (1.

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The interaction dynamics of signaling complexes is emerging as a key determinant that regulates the specificity of cellular responses. We present a combined experimental and computational study that quantifies the consequences of plasma membrane microcompartmentalization for the dynamics of type I interferon receptor complexes. By using long-term dual-color quantum dot (QD) tracking, we found that the lifetime of individual ligand-induced receptor heterodimers depends on the integrity of the membrane skeleton (MSK), which also proved important for efficient downstream signaling.

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A comment on the PCAST report: Skip the "match"/"non-match" stage.

Forensic Sci Int

March 2017

Forensic Statistician, Institute of Medical Informatics and Statistics, Kiel University, Kiel, Germany.

This letter comments on the report "Forensic science in criminal courts: Ensuring scientific validity of feature-comparison methods" recently released by the President's Council of Advisors on Science and Technology (PCAST). The report advocates a procedure for evaluation of forensic evidence that is a two-stage procedure in which the first stage is "match"/"non-match" and the second stage is empirical assessment of sensitivity (correct acceptance) and false alarm (false acceptance) rates. Almost always, quantitative data from feature-comparison methods are continuously-valued and have within-source variability.

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Synchronization and liquid crystalline order in soft active fluids.

Phys Rev Lett

April 2014

School of Mathematics, University of Bristol, Clifton, Bristol BS8 1TW, United Kingdom and Isaac Newton Institute for Mathematical Sciences, Cambridge CB3 0EH, United Kingdom.

We introduce a phenomenological theory for a new class of soft active fluids with the ability to synchronize. Our theoretical framework describes the macroscopic behavior of a collection of interacting anisotropic elements with cyclic internal dynamics and a periodic phase variable. This system can (i) spontaneously undergo a transition to a state with macroscopic orientational order, with the elements aligned, a liquid crystal, (ii) attain another broken symmetry state characterized by synchronization of their phase variables, or (iii) a combination of both types of order.

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Possible resonance effect of axionic dark matter in Josephson junctions.

Phys Rev Lett

December 2013

Isaac Newton Institute for Mathematical Sciences, University of Cambridge, 20 Clarkson Road, Cambridge CB3 0EH, United Kingdom and School of Mathematical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom.

We provide theoretical arguments that dark-matter axions from the galactic halo that pass through Earth may generate a small observable signal in resonant S/N/S Josephson junctions. The corresponding interaction process is based on the uniqueness of the gauge-invariant axion Josephson phase angle modulo 2π and is predicted to produce a small Shapiro steplike feature without externally applied microwave radiation when the Josephson frequency resonates with the axion mass. A resonance signal of so far unknown origin observed by C.

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Inertial effects in the response of viscous and viscoelastic fluids.

Phys Rev Lett

November 2005

Isaac Newton Institute for Mathematical Sciences, University of Cambridge, Cambridge, CB3 0EH, United Kingdom.

We consider the effect of inertia on the high frequency response of a general linear viscoelastic material to local deformations. We calculate the displacement response and correlation functions for points separated by a distance r. The effects of inertia and incompressibility lead to anticorrelations in the correlation or response functions, which become more pronounced for more elastic materials.

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