Testing the no-hair theorem with GW150914

We analyze gravitational-wave data from the first LIGO detection of a binary black-hole merger (GW150914) in search of the ringdown of the remnant black hole. Using observations beginning at the peak of the signal, we find evidence of the fundamental quasinormal mode and at least one overtone, both associated with the dominant angular mode ($\ell=m=2$), with $3.6\sigma$ confidence. A ringdown model including overtones allows us to measure the final mass and spin magnitude of the remnant exclusively from postinspiral data, obtaining an estimate in agreement with the values inferred from the full signal. The mass and spin values we measure from the ringdown agree with those obtained using solely the fundamental mode at a later time, but have smaller uncertainties. Agreement between the postinspiral measurements of mass and spin and those using the full waveform supports the hypothesis that the GW150914 merger produced a Kerr black hole, as predicted by general relativity, and provides a test of the no-hair theorem at the ${\sim}10\%$ level. An independent measurement of the frequency of the first overtone yields agreement with the no-hair hypothesis at the ${\sim 20}\%$ level. As the detector sensitivity improves and the detected population of black hole mergers grows, we can expect that using overtones will provide even stronger tests.Comment: v2: journal versio

Which Classes of Structures Are Both Pseudo-elementary and Definable by an Infinitary Sentence?

When classes of structures are not first-order definable, we might still try to find a nice description. There are two common ways for doing this. One is to expand the language, leading to notions of pseudo-elementary classes, and the other is to allow infinite conjuncts and disjuncts. In this paper we examine the intersection. Namely, we address the question: Which classes of structures are both pseudo-elementary and $\mathcal{L}_{\omega_1 \omega}$-elementary? We find that these are exactly the classes that can be defined by an infinitary formula that has no infinitary disjunctions

The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: RSD measurement from the power spectrum and bispectrum of the DR12 BOSS galaxies

We measure and analyse the bispectrum of the final, Data Release 12, galaxy sample provided by the Baryon Oscillation Spectroscopic Survey, splitting by selection algorithm into LOWZ and CMASS galaxies. The LOWZ sample contains 361\,762 galaxies with an effective redshift of $z_{\rm LOWZ}=0.32$, and the CMASS sample 777\,202 galaxies with an effective redshift of $z_{\rm CMASS}=0.57$. Combining the power spectrum, measured relative to the line-of-sight, with the spherically averaged bispectrum, we are able to constrain the product of the growth of structure parameter, $f$, and the amplitude of dark matter density fluctuations, $\sigma_8$, along with the geometric Alcock-Paczynski parameters, the product of the Hubble constant and the comoving sound horizon at the baryon drag epoch, $H(z)r_s(z_d)$, and the angular distance parameter divided by the sound horizon, $D_A(z)/r_s(z_d)$. After combining pre-reconstruction RSD analyses of the power spectrum monopole, quadrupole and bispectrum monopole; with post-reconstruction analysis of the BAO power spectrum monopole and quadrupole, we find $f(z_{\rm LOWZ})\sigma_8(z_{\rm LOWZ})=0.427\pm 0.056$, $D_A(z_{\rm LOWZ})/r_s(z_d)=6.60 \pm 0.13$, $H(z_{\rm LOWZ})r_s(z_d)=(11.55\pm 0.38)10^3\,{\rm kms}^{-1}$ for the LOWZ sample, and $f(z_{\rm CMASS})\sigma_8(z_{\rm CMASS})=0.426\pm 0.029$, $D_A(z_{\rm CMASS})/r_s(z_d)=9.39 \pm 0.10$, $H(z_{\rm CMASS})r_s(z_d)=(14.02\pm 0.22)10^3\,{\rm kms}^{-1}$ for the CMASS sample. We find general agreement with previous BOSS DR11 and DR12 measurements. Combining our dataset with {\it Planck15} we perform a null test of General Relativity (GR) through the $\gamma$-parametrisation finding $\gamma=0.733^{+0.068}_{-0.069}$, which is $\sim2.7\sigma$ away from the GR predictions.Comment: 34 pages, 22 figures, 8 tables. Accepted for publication in MNRAS. Data available at https://sdss3.org//science/boss_publications.ph

Book Reviews

Book reviews of: Behind the Big House: Reconciling Slavery, Race, and Heritage in the U.S. South. By Jodi Skipper (Iowa City: University of Iowa Press, 2022. Foreword, Acknowledgements, Introduction, Epilogue, Appendix A, Appendix B, Notes, Bibliography, Index. Pp. ix, 218. 27.50 paper. ISBN: 9781609388171.) Gin, Jesus, & Jim Crow: Prohibition and the Transformation of Racial and Religious Politics in the South. By Brendan J. J. Payne. (Baton Rouge: Louisiana State University Press, 2022. Pp. 304. 45 hardcover. ISBN: 0807171486.) The Women’s Fight: The Civil War’s Battles for Home, Freedom, and Nation. By Thavolia Glymph. (Chapel Hill: University of North Carolina Press, 2020. Acknowledgments, figures, notes, bibliography, index of names, index of subjects. Pp. 379. $37.50 cloth,$27.95 paper. ISBN: 9781469653631.) Until I Am Free: Fannie Lou Hamer’s Enduring Message to America. By Keisha N. Blain. (Boston: Beacon Press, 2021, Acknowledgements, notes, index, image credits, about the author. Pp ix, 181. $12.97 cloth,$24.95 paper. ISBN-13:9780807061503 Land of Milk and Money: The Creation of the Southern Dairy Industry. By Alan I. Marcus. (Baton Rouge: Louisiana State University Press, 2021. Acknowledgements, illustrations, notes, index. Pp. ix, 317. $50 cloth. ISBN: 0807176052.) Black Bodies in the River: Searching for Freedom Summer. By Davis W. Houck. (University Press of Mississippi, 2022. Preface, notes, index. Pp. ix, 153.$99 cloth, $25.00 paper. ISBN: 9781496840790.) Mississippi Zion: The Struggle for Liberation in Attala County, 1865–1915. By Evan Howard Ashford. (Jackson: University Press of Mississippi, 2022. Acknowledgements, illustrations, notes, index. Pp. ix, 233.$99 cloth, $25 paper. ISBN: 9781496839732

Hydrogen Peroxide Triggers a Dual Signaling Axis To Selectively Suppress Activated Human T Lymphocyte Migration

H2O2 is an early danger cue required for innate immune cell recruitment to wounds. To date, little is known about whether H2O2 is required for the migration of human adaptive immune cells to sites of inflammation. However, oxidative stress is known to impair T cell activity, induce actin stiffness, and inhibit cell polarization. In this study, we show that low oxidative concentrations of H2O2 also impede chemokinesis and chemotaxis of previously activated human T cells to CXCL11, but not CXCL10 or CXCL12. We show that this deficiency in migration is due to a reduction in inflammatory chemokine receptor CXCR3 surface expression and cellular activation of lipid phosphatase SHIP-1. We demonstrate that H2O2 acts through an Src kinase to activate a negative regulator of PI3K signaling, SHIP-1 via phosphorylation, providing a molecular mechanism for H2O2-induced chemotaxis deficiency. We hypothesize that although H2O2 serves as an early recruitment trigger for innate immune cells, it appears to operate as an inhibitor of T lymphocyte immune adaptive responses that are not required until later in the repair process

Assessing the impact of household participation on satisfaction and safe design in humanitarian shelter projects

Participation has long been considered important for post-disaster recovery. Establishing what constitutes participation in post-disaster shelter projects, however, has remained elusive, and the links between different types of participation and shelter programme outcomes are not well under-stood. Furthermore, recent case studies suggest that misguided participation strategies may beto blame for failures. This study analysed 19 shelter projects implemented in the Philippines following Typhoon Haiyan in November 2013 to identify the forms of participation employed.Using fuzzy-set qualitative comparative analysis, it assessed how household participation in the planning, design, and construction phases of shelter reconstruction led to outcomes of household satisfaction and safe shelter design. Participation was operationalised via eight central project tasks, revealing that the involvement of households in the early planning stages of projects and in construction activities were important for satisfaction and design outcomes, whereas engagement during the design phase of projects had little impact on the selected outcomes.</p

Which classes of structures are both pseudo-elementary and definable by an infinitary sentence?

When classes of structures are not first-order definable, we might still try to find a nice description. There are two common ways for doing this. One is to expand the language, leading to notions of pseudo-elementary classes, and the other is to allow infinite conjuncts and disjuncts. In this paper we examine the intersection. Namely, we address the question: Which classes of structures are both pseudo-elementary and Lω1,ω-elementary? We find that these are exactly the classes that can be defined by an infinitary formula that has no infinitary disjunctions.Natural Sciences and Engineering Research Council Discovery Grant 312501 || Natural Sciences and Engineering Research Council Banting Fellowshi

Which Classes of Structures are Both Pseudo-Elementary and Definable by an Infinitary Sentence

© The Author(s), 2023. Published by Cambridge University Press on behalf of The Association for Symbolic Logic.When classes of structures are not first-order definable, we might still try to find a nice description. There are two common ways for doing this. One is to expand the language, leading to notions of pseudo-elementary classes, and the other is to allow infinite conjuncts and disjuncts. In this paper we examine the intersection. Namely, we address the question: Which classes of structures are both pseudo elementary and Lω1,ω-elementary? We find that these are exactly the classes that can be defined by an infinitary formula that has no infinitary disjunctions