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18,282 results on '"Smith, George"'

4. All-orders moduli for type II flux backgrounds

Author

Smith, George R., Tennyson, David, and Waldram, Daniel

Subjects
High Energy Physics - Theory, Mathematics - Differential Geometry
Abstract

We investigate the old problem of determining the exact bulk moduli of generic $\mathrm{SU}(3)$-structure flux backgrounds of type II string theory. Using techniques from generalised geometry, we show that the infinitesimal deformations are counted by a spectral sequence in which the vertical maps are either de Rham or Dolbeault differentials (depending on the type of the exceptional complex structure (ECS)) and the horizontal maps are linear maps constructed from the flux and intrinsic torsion. Our calculation is exact, covering all possible supergravity $\mathrm{SU}(3)$-structure flux backgrounds including those which are not conformally Calabi--Yau, and goes beyond the usual linear approximation in three important ways: (i) we allow for finite flux; (ii) we consider perturbative higher-derivative corrections to the supergravity action; and (iii) we consider obstructions arising from higher-order deformations. Despite these extensions we find that the spectral sequence reproduces the na\"ive expectations that come from considering the effective superpotential in the small-flux limit. In particular, by writing the moduli in a form that is independent of the K\"ahler potential on the space of ECSs, and arguing the superpotential does not receive higher-derivative corrections, we show that the spectral sequence is perturbatively exact. Further, preliminary results show that a Tian--Todorov-like lemma implies that all the obstructions vanish. This has implications for the tadpole conjecture, showing that such perturbative, higher-order effects do not provide a way of circumventing the bound., Comment: 56+19pp, 1 figure

Published
2024

6. Back Cover

Author

Smith, George W. and Stowell, Daniel

Published
2017

10. At the Debate

Author

Smith, George W. and Stowell, Daniel

Published
2017

12. Douglas Closes

Author

Smith, George W. and Stowell, Daniel

Published
2017

13. The Departure

Author

Smith, George W. and Stowell, Daniel

Published
2017

14. A Tragic Ending

Author

Smith, George W. and Stowell, Daniel

Published
2017

15. Lincoln Replies

Author

Smith, George W. and Stowell, Daniel

Published
2017

17. Lincoln En Route

Author

Smith, George W. and Stowell, Daniel

Published
2017

18. Douglas En Route

Author

Smith, George W. and Stowell, Daniel

Published
2017

20. Some Traditions

Author

Smith, George W. and Stowell, Daniel

Published
2017

22. Lincoln in Egypt

Author

Smith, George W. and Stowell, Daniel

Published
2017

32. Contents

Author

Smith, George W. and Stowell, Daniel

Published
2017

34. Introduction

Author

Smith, George W. and Stowell, Daniel

Published
2017

35. Foreword

Author

Smith, George W. and Stowell, Daniel

Published
2017

37. Author's Preface

Author

Smith, George W. and Stowell, Daniel

Published
2017

40. Bounds on Fluctuations of First Passage Times for Counting Observables in Classical and Quantum Markov Processes

Author

Bakewell-Smith, George, Girotti, Federico, Guţă, Mădălin, and Garrahan, Juan P.

Subjects
Condensed Matter - Statistical Mechanics, Quantum Physics
Abstract

We study the statistics of first passage times (FPTs) of trajectory observables in both classical and quantum Markov processes. We consider specifically the FPTs of counting observables, that is, the times to reach a certain threshold of a trajectory quantity which takes values in the positive integers and is non-decreasing in time. For classical continuous-time Markov chains we rigorously prove: (i) a large deviation principle (LDP) for FPTs, whose corollary is a strong law of large numbers; (ii) a concentration inequality for the FPT of the dynamical activity, which provides an upper bound to the probability of its fluctuations to all orders; and (iii) an upper bound to the probability of the tails for the FPT of an arbitrary counting observable. For quantum Markov processes we rigorously prove: (iv) the quantum version of the LDP, and subsequent strong law of large numbers, for the FPTs of generic counts of quantum jumps; (v) a concentration bound for the the FPT of total number of quantum jumps, which provides an upper bound to the probability of its fluctuations to all orders, together with a similar bound for the sub-class of quantum reset processes which requires less strict irreducibility conditions; and (vi) a tail bound for the FPT of arbitrary counts. Our results allow to extend to FPTs the so-called "inverse thermodynamic uncertainty relations" that upper bound the size of fluctuations in time-integrated quantities. We illustrate our results with simple examples.

Published
2024

42. Genomic analysis of intracranial and subcortical brain volumes yields polygenic scores accounting for variation across ancestries

Author

García-Marín, Luis M., Campos, Adrian I., Diaz-Torres, Santiago, Rabinowitz, Jill A., Ceja, Zuriel, Mitchell, Brittany L., Grasby, Katrina L., Thorp, Jackson G., Agartz, Ingrid, Alhusaini, Saud, Ames, David, Amouyel, Philippe, Andreassen, Ole A., Arfanakis, Konstantinos, Arias-Vasquez, Alejandro, Armstrong, Nicola J., Athanasiu, Lavinia, Bastin, Mark E., Beiser, Alexa S., Bennett, David A., Bis, Joshua C., Boks, Marco P. M., Boomsma, Dorret I., Brodaty, Henry, Brouwer, Rachel M., Buitelaar, Jan K., Burkhardt, Ralph, Cahn, Wiepke, Calhoun, Vince D., Carmichael, Owen T., Chakravarty, Mallar, Chen, Qiang, Ching, Christopher R. K., Cichon, Sven, Crespo-Facorro, Benedicto, Crivello, Fabrice, Dale, Anders M., Smith, George Davey, de Geus, Eco J. C., De Jager, Philip L., de Zubicaray, Greig I., Debette, Stéphanie, DeCarli, Charles, Depondt, Chantal, Desrivières, Sylvane, Djurovic, Srdjan, Ehrlich, Stefan, Erk, Susanne, Espeseth, Thomas, Fernández, Guillén, Filippi, Irina, Fisher, Simon E., Fleischman, Debra A., Fletcher, Evan, Fornage, Myriam, Forstner, Andreas J., Francks, Clyde, Franke, Barbara, Ge, Tian, Goldman, Aaron L., Grabe, Hans J., Green, Robert C., Grimm, Oliver, Groenewold, Nynke A., Gruber, Oliver, Gudnason, Vilmundur, Håberg, Asta K., Haukvik, Unn K., Heinz, Andreas, Hibar, Derrek P., Hilal, Saima, Himali, Jayandra J., Ho, Beng-Choon, Hoehn, David F., Hoekstra, Pieter J., Hofer, Edith, Hoffmann, Wolfgang, Holmes, Avram J., Homuth, Georg, Hosten, Norbert, Ikram, M. Kamran, Ipser, Jonathan C., Jack Jr, Clifford R., Jahanshad, Neda, Jönsson, Erik G., Kahn, Rene S., Kanai, Ryota, Klein, Marieke, Knol, Maria J., Launer, Lenore J., Lawrie, Stephen M., Hellard, Stephanie Le, Lee, Phil H., Lemaître, Hervé, Li, Shuo, Liewald, David C. M., Lin, Honghuang, Longstreth, Jr, W. T., Lopez, Oscar L., Luciano, Michelle, Maillard, Pauline, Marquand, Andre F., Martin, Nicholas G., Martinot, Jean-Luc, Mather, Karen A., Mattay, Venkata S., McMahon, Katie L., Mecocci, Patrizia, Melle, Ingrid, Meyer-Lindenberg, Andreas, Mirza-Schreiber, Nazanin, Milaneschi, Yuri, Mosley, Thomas H., Mühleisen, Thomas W., Müller-Myhsok, Bertram, Maniega, Susana Muñoz, Nauck, Matthias, Nho, Kwangsik, Niessen, Wiro J., Nöthen, Markus M., Nyquist, Paul A., Oosterlaan, Jaap, Pandolfo, Massimo, Paus, Tomas, Pausova, Zdenka, Penninx, Brenda W. J. H., Pike, G. Bruce, Psaty, Bruce M., Pütz, Benno, Reppermund, Simone, Rietschel, Marcella D., Risacher, Shannon L., Romanczuk-Seiferth, Nina, Romero-Garcia, Rafael, Roshchupkin, Gennady V., Rotter, Jerome I., Sachdev, Perminder S., Sämann, Philipp G., Saremi, Arvin, Sargurupremraj, Muralidharan, Saykin, Andrew J., Schmaal, Lianne, Schmidt, Helena, Schmidt, Reinhold, Schofield, Peter R., Scholz, Markus, Schumann, Gunter, Schwarz, Emanuel, Shen, Li, Shin, Jean, Sisodiya, Sanjay M., Smith, Albert V., Smoller, Jordan W., Soininen, Hilkka S., Steen, Vidar M., Stein, Dan J., Stein, Jason L., Thomopoulos, Sophia I., Toga, Arthur W., Tordesillas-Gutiérrez, Diana, Trollor, Julian N., Valdes-Hernandez, Maria C., van ′t Ent, Dennis, van Bokhoven, Hans, van der Meer, Dennis, van der Wee, Nic J. A., Vázquez-Bourgon, Javier, Veltman, Dick J., Vernooij, Meike W., Villringer, Arno, Vinke, Louis N., Völzke, Henry, Walter, Henrik, Wardlaw, Joanna M., Weinberger, Daniel R., Weiner, Michael W., Wen, Wei, Westlye, Lars T., Westman, Eric, White, Tonya, Witte, A. Veronica, Wolf, Christiane, Yang, Jingyun, Zwiers, Marcel P., Ikram, M. Arfan, Seshadri, Sudha, Thompson, Paul M., Satizabal, Claudia L., Medland, Sarah E., and Rentería, Miguel E.

Published
2024
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43. Empirically assessing the plausibility of unconfoundedness in observational studies

Author

Hartwig, Fernando Pires, Tilling, Kate, and Smith, George Davey

Subjects
Statistics - Methodology
Abstract

The possibility of unmeasured confounding is one of the main limitations for causal inference from observational studies. There are different methods for partially empirically assessing the plausibility of unconfoundedness. However, most currently available methods require (at least partial) assumptions about the confounding structure, which may be difficult to know in practice. In this paper we describe a simple strategy for empirically assessing the plausibility of conditional unconfoundedness (i.e., whether the candidate set of covariates suffices for confounding adjustment) which does not require any assumptions about the confounding structure, requiring instead assumptions related to temporal ordering between covariates, exposure and outcome (which can be guaranteed by design), measurement error and selection into the study. The proposed method essentially relies on testing the association between a subset of covariates (those associated with the exposure given all other covariates) and the outcome conditional on the remaining covariates and the exposure. We describe the assumptions underlying the method, provide proofs, use simulations to corroborate the theory and illustrate the method with an applied example assessing the causal effect of length-for-age measured in childhood and intelligence quotient measured in adulthood using data from the 1982 Pelotas (Brazil) birth cohort. We also discuss the implications of measurement error and some important limitations.

Published
2024

49. Impact of vaccination on the association of COVID-19 with cardiovascular diseases: An OpenSAFELY cohort study

Author

Cezard, Genevieve I., Denholm, Rachel E., Knight, Rochelle, Wei, Yinghui, Teece, Lucy, Toms, Renin, Forbes, Harriet J., Walker, Alex J., Fisher, Louis, Massey, Jon, Hopcroft, Lisa E. M., Horne, Elsie M. F., Taylor, Kurt, Palmer, Tom, Arab, Marwa Al, Cuitun Coronado, Jose Ignacio, Ip, Samantha H. Y., Davy, Simon, Dillingham, Iain, Bacon, Sebastian, Mehrkar, Amir, Morton, Caroline E., Greaves, Felix, Hyams, Catherine, Davey Smith, George, Macleod, John, Chaturvedi, Nishi, Goldacre, Ben, Whiteley, William N., Wood, Angela M., Sterne, Jonathan A. C., and Walker, Venexia

Published
2024
Full Text
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