John D. Chodera
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
A Closure Scheme for Chemical Master Equations
A closure scheme for chemical master equations Patrick Smadbeck and Yiannis N. Kaznessis1 Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455 Edited by Wing Hung Wong, Stanford University, Stanford, CA, and approved July 16, 2013 (received for review April 8, 2013) Probability reigns in biology, with random molecular events dictating equation governs the evolution of the probability, PðX; tÞ,thatthe the fate of individual organisms, and propelling populations of system is at state X at time t: species through evolution. In principle, the master probability À Á equation provides the most complete model of probabilistic behavior ∂P X; t X À Á À Á À Á À Á = T X X′ P X′; t − T X′ X P X; t : [1] in biomolecular networks. In practice, master equations describing ∂t complex reaction networks have remained unsolved for over 70 X′ years. This practical challenge is a reason why master equations, for À Á all their potential, have not inspired biological discovery. Herein, we This is a probability conservation equation, where T X X′ is present a closure scheme that solves the master probability equation the transition propensity from any possible state X′ to state X of networks of chemical or biochemical reactions. We cast the master per unit time. In a network of chemical or biochemical reactions, equation in terms of ordinary differential equations that describe the the transition probabilities are defined by the reaction-rate laws time evolution of probability distribution moments. We postulate as a set of Poisson-distributed reaction propensities; these simply that a finite number of moments capture all of the necessary dictate how many reaction events take place per unit time. -
Fluctuations of Spacetime and Holographic Noise in Atomic Interferometry
General Relativity and Gravitation (2011) DOI 10.1007/s10714-010-1137-7 RESEARCHARTICLE Ertan Gokl¨ u¨ · Claus Lammerzahl¨ Fluctuations of spacetime and holographic noise in atomic interferometry Received: 10 December 2009 / Accepted: 12 December 2010 c Springer Science+Business Media, LLC 2010 Abstract On small scales spacetime can be understood as some kind of space- time foam of fluctuating bubbles or loops which are expected to be an outcome of a theory of quantum gravity. One recently discussed model for this kind of space- time fluctuations is the holographic principle which allows to deduce the structure of these fluctuations. We review and discuss two scenarios which rely on the holo- graphic principle leading to holographic noise. One scenario leads to fluctuations of the spacetime metric affecting the dynamics of quantum systems: (i) an appar- ent violation of the equivalence principle, (ii) a modification of the spreading of wave packets, and (iii) a loss of quantum coherence. All these effects can be tested with cold atoms. Keywords Quantum gravity phenomenology, Holographic principle, Spacetime fluctuations, UFF, Decoherence, Wavepacket dynamics 1 Introduction The unification of quantum mechanics and General Relativity is one of the most outstanding problems of contemporary physics. Though yet there is no theory of quantum gravity. There are a lot of reasons why gravity must be quantized [33]. For example, (i) because of the fact that all matter fields are quantized the interactions, generated by theses fields, must also be quantized. (ii) In quantum mechanics and General Relativity the notion of time is completely different. (iii) Generally, in General Relativity singularities necessarily appear where physical laws are not valid anymore. -
Ontology-Based Methods for Analyzing Life Science Data
Habilitation a` Diriger des Recherches pr´esent´ee par Olivier Dameron Ontology-based methods for analyzing life science data Soutenue publiquement le 11 janvier 2016 devant le jury compos´ede Anita Burgun Professeur, Universit´eRen´eDescartes Paris Examinatrice Marie-Dominique Devignes Charg´eede recherches CNRS, LORIA Nancy Examinatrice Michel Dumontier Associate professor, Stanford University USA Rapporteur Christine Froidevaux Professeur, Universit´eParis Sud Rapporteure Fabien Gandon Directeur de recherches, Inria Sophia-Antipolis Rapporteur Anne Siegel Directrice de recherches CNRS, IRISA Rennes Examinatrice Alexandre Termier Professeur, Universit´ede Rennes 1 Examinateur 2 Contents 1 Introduction 9 1.1 Context ......................................... 10 1.2 Challenges . 11 1.3 Summary of the contributions . 14 1.4 Organization of the manuscript . 18 2 Reasoning based on hierarchies 21 2.1 Principle......................................... 21 2.1.1 RDF for describing data . 21 2.1.2 RDFS for describing types . 24 2.1.3 RDFS entailments . 26 2.1.4 Typical uses of RDFS entailments in life science . 26 2.1.5 Synthesis . 30 2.2 Case study: integrating diseases and pathways . 31 2.2.1 Context . 31 2.2.2 Objective . 32 2.2.3 Linking pathways and diseases using GO, KO and SNOMED-CT . 32 2.2.4 Querying associated diseases and pathways . 33 2.3 Methodology: Web services composition . 39 2.3.1 Context . 39 2.3.2 Objective . 40 2.3.3 Semantic compatibility of services parameters . 40 2.3.4 Algorithm for pairing services parameters . 40 2.4 Application: ontology-based query expansion with GO2PUB . 43 2.4.1 Context . 43 2.4.2 Objective . -
Ploidetect Enables Pan-Cancer Analysis of the Causes and Impacts of Chromosomal Instability
bioRxiv preprint doi: https://doi.org/10.1101/2021.08.06.455329; this version posted August 8, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Ploidetect enables pan-cancer analysis of the causes and impacts of chromosomal instability Luka Culibrk1,2, Jasleen K. Grewal1,2, Erin D. Pleasance1, Laura Williamson1, Karen Mungall1, Janessa Laskin3, Marco A. Marra1,4, and Steven J.M. Jones1,4, 1Canada’s Michael Smith Genome Sciences Center at BC Cancer, Vancouver, British Columbia, Canada 2Bioinformatics training program, University of British Columbia, Vancouver, British Columbia, Canada 3Department of Medical Oncology, BC Cancer, Vancouver, British Columbia, Canada 4Department of Medical Genetics, Faculty of Medicine, Vancouver, British Columbia, Canada Cancers routinely exhibit chromosomal instability, resulting in tumors mutate, these variants are considerably more difficult the accumulation of changes in the abundance of genomic ma- to detect accurately compared to other types of mutations terial, known as copy number variants (CNVs). Unfortunately, and consequently they may represent an under-explored the detection of these variants in cancer genomes is difficult. We facet of tumor biology. 20 developed Ploidetect, a software package that effectively iden- While small mutations can be determined through base tifies CNVs within whole-genome sequenced tumors. Ploidetect changes embedded within aligned sequence reads, CNVs was more sensitive to CNVs in cancer related genes within ad- are variations in DNA quantity and are typically determined vanced, pre-treated metastatic cancers than other tools, while also segmenting the most contiguously. -
BIOINFORMATICS APPLICATIONS NOTE Pages 380-381
Vol. 14 no. 4 1998 BIOINFORMATICS APPLICATIONS NOTE Pages 380-381 MView: a web-compatible database search or multiple alignment viewer NigelP. Brown, ChristopheLeroy and Chris Sander European Bioinformatics Institute (EMBLĆEBI), Wellcome Genome Campus, CambridgeCB10 1SD, UK Received on December 10, 1997; revised and accepted on January 15, 1998 Abstract may be hyperlinked to the SRS system (Etzold et al., 1996), a text field, a field of scoring information from searches, and Summary: MView is a tool for converting the results of a a field reporting the per cent identity of each sequence with sequence database search into the form of a coloured multiple respect to a preferred sequence in the alignment, usually the alignment of hits stacked against the query. Alternatively, an query in the case of a search. existing multiple alignment can be processed. In either case, Multiple alignments require minimal parsing and are the output is simply HTML, so the result is platform independent and does not require a separate application or subjected only to formatting stages. Search hits are first applet to be loaded. stacked against the ungapped query sequence and require Availability: Free from http://www.sander.ebi.ac.uk/mview/ special processing. Ungapped search (e.g. BLAST) hit subject to copyright restrictions. fragments are assembled into a single string by overlaying Contact: [email protected] them preferentially by score onto a template string, while gapped search (e.g. FASTA) hits have columns corresponding Often when running FASTA (Pearson, 1990) or BLAST to query gaps excised. Consequently, the stacked alignment is (Altschul et al., 1990), it is desired to visualize the database a patchwork of reconstituted sequences that nevertheless is hits stacked against the query sequence. -
Are You an Invited Speaker? a Bibliometric Analysis of Elite Groups for Scholarly Events in Bioinformatics
Are You an Invited Speaker? A Bibliometric Analysis of Elite Groups for Scholarly Events in Bioinformatics Senator Jeong, Sungin Lee, and Hong-Gee Kim Biomedical Knowledge Engineering Laboratory, Seoul National University, 28–22 YeonGeon Dong, Jongno Gu, Seoul 110–749, Korea. E-mail: {senator, sunginlee, hgkim}@snu.ac.kr Participating in scholarly events (e.g., conferences, work- evaluation, but it would be hard to claim that they have pro- shops, etc.) as an elite-group member such as an orga- vided comprehensive lists of evaluation measurements. This nizing committee chair or member, program committee article aims not to provide such lists but to add to the current chair or member, session chair, invited speaker, or award winner is beneficial to a researcher’s career develop- practices an alternative metric that complements existing per- ment.The objective of this study is to investigate whether formance measures to give a more comprehensive picture of elite-group membership for scholarly events is represen- scholars’ performance. tative of scholars’ prominence, and which elite group is By one definition (Jeong, 2008), a scholarly event is the most prestigious. We collected data about 15 global “a sequentially and spatially organized collection of schol- (excluding regional) bioinformatics scholarly events held in 2007. We sampled (via stratified random sampling) ars’ interactions with the intention of delivering and shar- participants from elite groups in each event. Then, bib- ing knowledge, exchanging research ideas, and performing liometric indicators (total citations and h index) of seven related activities.” As such, scholarly events are communica- elite groups and a non-elite group, consisting of authors tion channels from which our new evaluation tool can draw who submitted at least one paper to an event but were its supporting evidence. -
Semi-Classical Lindblad Master Equation for Spin Dynamics
Journal of Physics A: Mathematical and Theoretical J. Phys. A: Math. Theor. 54 (2021) 235201 (13pp) https://doi.org/10.1088/1751-8121/abf79b Semi-classical Lindblad master equation for spin dynamics Jonathan Dubois∗ ,UlfSaalmann and Jan M Rost Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187 Dresden, Germany E-mail: [email protected], [email protected] and [email protected] Received 25 January 2021, revised 18 March 2021 Accepted for publication 13 April 2021 Published 7 May 2021 Abstract We derive the semi-classical Lindblad master equation in phase space for both canonical and non-canonicalPoisson brackets using the Wigner–Moyal formal- ism and the Moyal star-product. The semi-classical limit for canonical dynam- ical variables, i.e. canonical Poisson brackets, is the Fokker–Planck equation, as derived before. We generalize this limit and show that it holds also for non- canonical Poisson brackets. Examples are gyro-Poisson brackets, which occur in spin ensembles, systems of recent interest in atomic physics and quantum optics. We show that the equations of motion for the collective spin variables are given by the Bloch equations of nuclear magnetization with relaxation. The Bloch and relaxation vectors are expressed in terms of the microscopic operators: the Hamiltonian and the Lindblad functions in the Wigner–Moyal formalism. Keywords: Lindblad master equations,non-canonicalvariables,Hamiltonian systems, spin systems, classical and semi-classical limit, thermodynamical limit (Some fgures may appear in colour only in the online journal) 1. Lindblad quantum master equation Since perfect isolation of a system is an idealization [1, 2], open microscopic systems, which interact with an environment, are prevalent in nature as well as in experiments. -
Full List of PCAWG Consortium Working Groups and Writing
Supplementary information to: Genomics: data sharing needs an international code of conduct To accompany a Comment published in Nature 578, 31–33 (2020) https://www.nature.com/articles/d41586-020-00082-9 By Mark Phillips, Fruzsina Molnár-Gábor, Jan O. Korbel, Adrian Thorogood, Yann Joly, Don Chalmers, David Townend & Bartha M. Knoppers for the PCAWG Consortium. SUPPLEMENTARY INFORMATION | NATURE | 1 The ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium Working Groups PCAWG Steering committee 1,2 3,4,5,6 7,8 9,10 Peter J Campbell# , Gad Getz# , Jan O Korbel# , Lincoln D Stein# and Joshua M Stuart#11,12 PCAWG Head of project management Jennifer L Jennings13 PCAWG Executive committee 14 15 16 17 18 Sultan T Al-Sedairy , Axel Aretz , Cindy Bell , Miguel Betancourt , Christiane Buchholz , 19 20 21 22 23 Fabien Calvo , Christine Chomienne , Michael Dunn , Stuart Edmonds , Eric Green , Shailja 24 23 25 13 26 Gupta , Carolyn M Hutter , Karine Jegalian , Jennifer L Jennings , Nic Jones , Hyung-Lae 27 28,29,30 31 32 32 26 Kim , Youyong Lu , Hitoshi Nakagama , Gerd Nettekoven , Laura Planko , David Scott , 3 3,34 35 9,10 1 35 Tatsuhiro Shibata , Kiyo Shimizu , Lincoln D Stein# , Michael R Stratton , Takashi Yugawa , 36,37 24 38 39 Giampaolo Tortora , K VijayRaghavan , Huanming Yang and Jean C Zenklusen PCAWG Ethics and Legal Working Group 40 41 41 42 41 Don Chalmers# , Yann Joly , Bartha M Knoppers# , Fruzsina -
The Master Equation
The Master Equation Johanne Hizanidis November 2002 Contents 1 Stochastic Processes 1 1.1 Why and how do stochastic processes enter into physics? . 1 1.2 Brownian Motion: a stochastic process . 2 2 Markov processes 2 2.1 The conditional probability . 2 2.2 Markov property . 2 3 The Chapman-Kolmogorov (C-K) equation 3 3.1 The C-K equation for stationary and homogeneous processes . 3 4 The Master equation 4 4.1 Derivation of the Master equation from the C-K equation . 4 4.2 Detailed balance . 5 5 The mean-field equation 5 6 One-step processes: examples 7 6.1 The Poisson process . 8 6.2 The decay process . 8 6.3 A Chemical reaction . 9 A Appendix 11 1 STOCHASTIC PROCESSES 1 Stochastic Processes A stochastic process is the time evolution of a stochastic variable. So if Y is the stochastic variable, the stochastic process is Y (t). A stochastic variable is defined by specifying the set of possible values called 'range' or 'set of states' and the probability distribution over this set. The set can be discrete (e.g. number of molecules of a component in a reacting mixture),continuous (e.g. the velocity of a Brownian particle) or multidimensional. In the latter case, the stochastic variable is a vector (e.g. the three velocity components of a Brownian particle). The figure below helps to get a more intuitive idea of a (discrete) stochastic process. At successive times, the most probable values of Y have been drawn as heavy dots. We may select a most probable trajectory from such a picture. -
Master Equation: Biological Applications and Thermodynamic Description
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by AMS Tesi di Dottorato Alma Mater Studiorum · Universita` di Bologna FACOLTA` DI SCIENZE MATEMATICHE, FISICHE E NATURALI Dottorato in Fisica SETTORE CONCORSUALE: 02/B3-FISICA APPLICATA SETTORE SCIENTIFICO-DISCIPLINARE:FIS/07-FISICA APPLICATA Master Equation: Biological Applications and Thermodynamic Description Thesis Advisor: Presented by: Chiar.mo Prof. LUCIANA RENATA DE GASTONE CASTELLANI OLIVEIRA PhD coordinator: Chiar.mo Prof. FABIO ORTOLANI aa 2013/2014 January 10, 2014 I dedicate this thesis to my parents. Introduction It is well known that many realistic mathematical models of biological systems, such as cell growth, cellular development and differentiation, gene expression, gene regulatory networks, enzyme cascades, synaptic plasticity, aging and population growth need to include stochasticity. These systems are not isolated, but rather subject to intrinsic and extrinsic fluctuations, which leads to a quasi equilibrium state (homeostasis). Any bio-system is the result of a combined action of genetics and environment where the pres- ence of fluctuations and noise cannot be neglected. Dealing with population dynamics of individuals (or cells) of one single species (or of different species) the deterministic description is usually not adequate unless the populations are very large. Indeed the number of individuals varies randomly around a mean value, which obeys deterministic laws, but the relative size of fluctu- ations increases as the size of the population becomes smaller and smaller. As consequence, very large populations can be described by logistic type or chemical kinetics equations but as long as the size is below N = 103 ∼ 104 units a new framework needs to be introduced. -
Biological Pathways Exchange Language Level 3, Release Version 1 Documentation
BioPAX – Biological Pathways Exchange Language Level 3, Release Version 1 Documentation BioPAX Release, July 2010. The BioPAX data exchange format is the joint work of the BioPAX workgroup and Level 3 builds on the work of Level 2 and Level 1. BioPAX Level 3 input from: Mirit Aladjem, Ozgun Babur, Gary D. Bader, Michael Blinov, Burk Braun, Michelle Carrillo, Michael P. Cary, Kei-Hoi Cheung, Julio Collado-Vides, Dan Corwin, Emek Demir, Peter D'Eustachio, Ken Fukuda, Marc Gillespie, Li Gong, Gopal Gopinathrao, Nan Guo, Peter Hornbeck, Michael Hucka, Olivier Hubaut, Geeta Joshi- Tope, Peter Karp, Shiva Krupa, Christian Lemer, Joanne Luciano, Irma Martinez-Flores, Zheng Li, David Merberg, Huaiyu Mi, Ion Moraru, Nicolas Le Novere, Elgar Pichler, Suzanne Paley, Monica Penaloza- Spinola, Victoria Petri, Elgar Pichler, Alex Pico, Harsha Rajasimha, Ranjani Ramakrishnan, Dean Ravenscroft, Jonathan Rees, Liya Ren, Oliver Ruebenacker, Alan Ruttenberg, Matthias Samwald, Chris Sander, Frank Schacherer, Carl Schaefer, James Schaff, Nigam Shah, Andrea Splendiani, Paul Thomas, Imre Vastrik, Ryan Whaley, Edgar Wingender, Guanming Wu, Jeremy Zucker BioPAX Level 2 input from: Mirit Aladjem, Gary D. Bader, Ewan Birney, Michael P. Cary, Dan Corwin, Kam Dahlquist, Emek Demir, Peter D'Eustachio, Ken Fukuda, Frank Gibbons, Marc Gillespie, Michael Hucka, Geeta Joshi-Tope, David Kane, Peter Karp, Christian Lemer, Joanne Luciano, Elgar Pichler, Eric Neumann, Suzanne Paley, Harsha Rajasimha, Jonathan Rees, Alan Ruttenberg, Andrey Rzhetsky, Chris Sander, Frank Schacherer, -
2. Kinetic Theory
2. Kinetic Theory The purpose of this section is to lay down the foundations of kinetic theory, starting from the Hamiltonian description of 1023 particles, and ending with the Navier-Stokes equation of fluid dynamics. Our main tool in this task will be the Boltzmann equation. This will allow us to provide derivations of the transport properties that we sketched in the previous section, but without the more egregious inconsistencies that crept into our previous derivaion. But, perhaps more importantly, the Boltzmann equation will also shed light on the deep issue of how irreversibility arises from time-reversible classical mechanics. 2.1 From Liouville to BBGKY Our starting point is simply the Hamiltonian dynamics for N identical point particles. Of course, as usual in statistical mechanics, here is N ridiculously large: N ∼ O(1023) or something similar. We will take the Hamiltonian to be of the form 1 N N H = !p 2 + V (!r )+ U(!r − !r ) (2.1) 2m i i i j i=1 i=1 i<j ! ! ! The Hamiltonian contains an external force F! = −∇V that acts equally on all parti- cles. There are also two-body interactions between particles, captured by the potential energy U(!ri − !rj). At some point in our analysis (around Section 2.2.3) we will need to assume that this potential is short-ranged, meaning that U(r) ≈ 0forr % d where, as in the last Section, d is the atomic distance scale. Hamilton’s equations are ∂!p ∂H ∂!r ∂H i = − , i = (2.2) ∂t ∂!ri ∂t ∂!pi Our interest in this section will be in the evolution of a probability distribution, f(!ri, p!i; t)overthe2N dimensional phase space.