790 research outputs found
Deriving analytic solutions for compact binary inspirals without recourse to adiabatic approximations
We utilize the dynamical renormalization group formalism to calculate the
real space trajectory of a compact binary inspiral for long times via a
systematic resummation of secularly growing terms. This method generates closed
form solutions without orbit averaging, and the accuracy can be systematically
improved. The expansion parameter is where is the
initial time, is the time elapsed, and and are the angular
orbital frequency and initial speed, respectively, and is the binary's
symmetric mass ratio. We demonstrate how to apply the renormalization group
method to resum solutions beyond leading order in two ways. First, we calculate
the second order corrections of the leading radiation reaction force, which
involves highly non-trivial checks of the formalism (i.e. its
renormalizability). Second, we show how to systematically include
post-Newtonian corrections to the radiation reaction force. By avoiding orbit
averaging we gain predictive power and eliminate ambiguities in the initial
conditions. Finally, we discuss how this methodology can be used to find
analytic solutions to the spin equations of motion that are valid over long
times.Comment: 18 pages, 2 figure
Reply to "Comment on 'Finite size corrections to the radiation reaction force in classical electrodynamics'"
We reply to P. Forg\'acs, T. Herpay, and P. Kov\'acs (arXiv: 1202.6289).Comment: 1 page. To be published in Physical Review Letter
Composition
When some objects are the parts of another object, they compose that object and
that object is composite. This article is intended as an introduction to the central questions
about composition and a highly selective overview of various answers to those questions.
In §1, we review some formal features of parthood that are important for understanding
the nature of composition. In §2, we consider some answers to the question: which
pluralities of objects together compose something? As we will see, the dominant answers
are all of them and none of them. In §§3-4, we examine one of the main arguments that
has driven philosophers to these extreme answers: the argument from vagueness. In §5,
we turn to the question of whether composition is unique: is it sometimes the case that
some things compose more than one thing? Finally, in §6, we turn from the question of
which composites exist to the question of which composites exist fundamentally
What Do the Folk Think about Composition and Does it Matter?
Rose and Schaffer (forthcoming) argue that teleological thinking has a substantial influence on folk intuitions about composition. They take this to show (i) that we should not rely on folk intuitions about composition and (ii) that we therefore should not reject theories of composition on the basis of intuitions about composition. We cast doubt on the teleological interpretation of folk judgments about composition; we show how their debunking argument can be resisted, even on the assumption that folk intuitions have a teleological source; and we argue that, even if folk intuitions about composition carry no weight, theories of composition can still be rejected on the basis of the intuitions of metaphysicians
Consumption of Sugar-Sweetened Beverages Associated With Increased Odds of Depression
Objective: To evaluate the association between depression and sugary drink intake using participant data from the Behavioral Risk Factor Surveillance Survey (BRFSS).
Design: Cross-sectional data from the 2012 and 2013 BRFSS were examined (N=44,603). Depression was based on self-report of symptoms within the past 30 days. Covariates included age, sex, race, employment status, body mass index (BMI), education level, and exercise in the past 30 days.
Setting: Data from a national telephone survey (BRFSS) were used to assess risk factors associated with health of the participants.
Subjects: Participants in the 2012 and 2013 BRFSS were included in this analysis (N=44,603). Results: Adjusting for confounders, the odds of depression increased by 5% for every sugary drink consumed (odds ratio (OR)=1.06, 95% confidence interval (CI)=1.02-1.10). Depression was also associated with race, with non-Hispanic blacks being 60% more likely to be depressed than non-Hispanic whites. Unemployment and having a high school or less education were independently associated with depression. The association of depression and consumption of sugar sweetened beverages was stronger among women than men.
Conclusion: This study indicates that consuming sugary drinks are associated with an increased odds of depression. These findings support advocacy efforts for an overall healthy lifestyle. In addition, future research should evaluate this association using a cohort design in order to establish the temporality of this association
Finite size corrections to the radiation reaction force in classical electrodynamics
We introduce an effective field theory approach that describes the motion of
finite size objects under the influence of electromagnetic fields. We prove
that leading order effects due to the finite radius of a spherically
symmetric charge is order rather than order in any physical model, as
widely claimed in the literature. This scaling arises as a consequence of
Poincar\'e and gauge symmetries, which can be shown to exclude linear
corrections. We use the formalism to calculate the leading order finite size
correction to the Abraham-Lorentz-Dirac force.Comment: 4 pages, 2 figure
Joint searches between gravitational-wave interferometers and high-energy neutrino telescopes: science reach and analysis strategies
Many of the astrophysical sources and violent phenomena observed in our
Universe are potential emitters of gravitational waves (GWs) and high-energy
neutrinos (HENs). A network of GW detectors such as LIGO and Virgo can
determine the direction/time of GW bursts while the IceCube and ANTARES
neutrino telescopes can also provide accurate directional information for HEN
events. Requiring the consistency between both, totally independent, detection
channels shall enable new searches for cosmic events arriving from potential
common sources, of which many extra-galactic objects.Comment: 4 pages. To appear in the Proceedings of the 2d Heidelberg Workshop:
"High-Energy Gamma-rays and Neutrinos from Extra-Galactic Sources",
Heidelberg (Germany), January 13-16, 200
Massively Parallel Sequencing of Human Urinary Exosome/Microvesicle RNA Reveals a Predominance of Non-Coding RNA
Intact RNA from exosomes/microvesicles (collectively referred to as microvesicles) has sparked much interest as potential biomarkers for the non-invasive analysis of disease. Here we use the Illumina Genome Analyzer to determine the comprehensive array of nucleic acid reads present in urinary microvesicles. Extraneous nucleic acids were digested using RNase and DNase treatment and the microvesicle inner nucleic acid cargo was analyzed with and without DNase digestion to examine both DNA and RNA sequences contained in microvesicles. Results revealed that a substantial proportion (∼87%) of reads aligned to ribosomal RNA. Of the non-ribosomal RNA sequences, ∼60% aligned to non-coding RNA and repeat sequences including LINE, SINE, satellite repeats, and RNA repeats (tRNA, snRNA, scRNA and srpRNA). The remaining ∼40% of non-ribosomal RNA reads aligned to protein coding genes and splice sites encompassing approximately 13,500 of the known 21,892 protein coding genes of the human genome. Analysis of protein coding genes specific to the renal and genitourinary tract revealed that complete segments of the renal nephron and collecting duct as well as genes indicative of the bladder and prostate could be identified. This study reveals that the entire genitourinary system may be mapped using microvesicle transcript analysis and that the majority of non-ribosomal RNA sequences contained in microvesicles is potentially functional non-coding RNA, which play an emerging role in cell regulation
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