A small universe after all?

The cosmic microwave background radiation allows us to measure both the geometry and topology of the universe. It has been argued that the COBE-DMR data already rule out models that are multiply connected on scales smaller than the particle horizon. Here we show the opposite is true: compact (small) hyperbolic universes are favoured over their infinite counterparts. For a density parameter of Omega_o=0.3, the compact models are a better fit to COBE-DMR (relative likelihood ~20) and the large-scale structure data (sigma_8 increases by ~25%).Comment: 4 pages, RevTeX, 7 Figure

Detection of relic gravitational waves in the CMB: Prospects for CMBPol mission

Detection of relic gravitational waves, through their imprint in the cosmic microwave background radiation, is one of the most important tasks for the planned CMBPol mission. In the simplest viable theoretical models the gravitational wave background is characterized by two parameters, the tensor-to-scalar ratio $r$ and the tensor spectral index $n_t$. In this paper, we analyze the potential joint constraints on these two parameters, $r$ and $n_t$, using the potential observations of the CMBPol mission, which is expected to detect the relic gravitational waves if $r\gtrsim0.001$. The influence of the contaminations, including cosmic weak lensing, various foreground emissions, and systematical errors, is discussed.Comment: 26 pages, 19 figures, 4 tables; JCAP in pres

Description of the inelastic collision of two solitary waves for the BBM equation

We prove that the collision of two solitary waves of the BBM equation is inelastic but almost elastic in the case where one solitary wave is small in the energy space. We show precise estimates of the nonzero residue due to the collision. Moreover, we give a precise description of the collision phenomenon (change of size of the solitary waves).Comment: submitted for publication. Corrected typo in Theorem 1.

The impact of nature of onset of pain and posttraumatic stress on adjustment to chronic pain and treatment outcome

Despite the demonstrated efficacy of cognitive-behavioural therapy for chronic pain, recent research has attempted to identify predictors of treatment outcome in order to improve the effectiveness of such treatments. This research has indicated that variables such as the nature of the onset of the pain and psychopathology are associated with poor adjustment to chronic pain. Accordingly, these variables might also be predictive of poor response to treatment. Individuals who experience a sudden onset of pain following an injury or accident, particularly when the instigating event is experienced as psychologically traumatic, may present for treatment with high levels of distress, including symptoms consistent with a posttraumatic stress response. The impact of this type of onset of pain and posttraumatic stress symptoms on adjustment to chronic pain and treatment outcome is the focus of this thesis. Three studies were conducted to clarify and extend earlier research findings in this area. Using 536 patients referred for treatment in a tertiary referral pain management centre, the first study examined the psychometric properties of a widely used self-report measure of posttraumatic stress symptoms (the PTSD Checklist, or PCL), modified for use in a chronic pain sample. This study provided preliminary support for the suitability of the PCL as a self-report measure of Posttraumatic Stress Disorder (PTSD) symptoms in chronic pain patients. However, the study also highlighted a number of issues with the use of self-report measures of posttraumatic stress symptoms in chronic pain patient samples. In particular, PCL items enquiring about symptoms which are a common aspect of the chronic pain experience (e.g. irritability, sleep problems) appeared to contribute to high mean scores on the PCL Avoidance and Arousal subscales. Furthermore, application of diagnostic cut-off scores and an algorithm recommended for the PCL in other trauma groups suggested that a much larger proportion of the sample was identified as potentially meeting diagnostic criteria for PTSD than would have been expected from previous research. The second study utilised the modified PCL to investigate the impact of different types of onset of pain (e.g. traumatic onset) and posttraumatic stress symptoms on adjustment to chronic pain in a sample of 196 chronic pain patients referred to the same centre. For patients who experienced the onset of pain related to a specific event, two independent experts in the field of PTSD determined whether these events satisfied the definition of a traumatic event according to DSM-IV diagnostic criteria. Adjustment was assessed through a number of validated measures of mood, disability, pain experience, and pain-related cognitions. Contrary to expectations, comparisons between patients who had experienced different types of onset of pain revealed few significant differences between them. That is, analyses comparing patients presenting with accident-related pain, or pain related to other specific events, to patients who had experienced spontaneous or insidious onset of pain revealed no significant differences between the groups on measures of pain severity, pain-related disability, and symptoms of affective distress after adjustment for age, pain duration, and compensation status. Similarly, comparisons between patients who had experienced a potentially traumatic onset of pain with those who had experienced a non-traumatic or spontaneous or insidious onset of pain also revealed no significant differences on the aforementioned variables. In contrast, compensation status, age, and a number of cognitive variables were significant predictors of pain severity, pain-related disability, and depression. The final study investigated the impact of type of pain onset and posttraumatic stress symptoms on response to a multidisciplinary cognitive-behavioural pain management program. Unlike the previous study, this treatment outcome study revealed a number of differences between onset groups. Most notably, patients who had experienced an insidious or spontaneous onset of pain reported greater improvements in pain severity and maintained these improvements more effectively over a one month period than patients who had experienced pain in the context of an accident or other specific incident. There was also limited evidence that improvements in depression favoured patients who had experienced an insidious or spontaneous and non-traumatic onset of pain. Consistent with this, posttraumatic stress symptoms were a significant predictor of treatment outcome, with higher levels of symptoms being associated with smaller improvements in pain-related disability and distress. Notably, this study also revealed that certain cognitive variables (i.e. catastrophising, self-efficacy, and fear-avoidance beliefs) were also significant predictors of treatment outcome, consistent with previous findings in the pain literature. This provided some perspective on the relative roles of both PTSD symptoms and cognitive variables in adjustment to persisting pain and treatment response. These findings were all consistent with expectations and with previous research. Implications for future research and for the assessment and treatment of chronic pain patients who present with posttraumatic stress symptoms are discussed

The luminosities of protostars in the spitzer c2d and gould belt legacy clouds

Journal ArticlePublished version available online at the Astronomical Journal, Volume 145, Number 4, Article 94; doi: doi: 10.1088/0004-6256/145/4/94Motivated by the long-standing "luminosity problem" in low-mass star formation whereby protostars are underluminous compared to theoretical expectations, we identify 230 protostars in 18 molecular clouds observed by two Spitzer Space Telescope Legacy surveys of nearby star-forming regions. We compile complete spectral energy distributions, calculate L bol for each source, and study the protostellar luminosity distribution. This distribution extends over three orders of magnitude, from 0.01 L ȯ to 69 L ȯ, and has a mean and median of 4.3 L ȯ and 1.3 L ȯ, respectively. The distributions are very similar for Class 0 and Class I sources except for an excess of low luminosity (L bol ≲ 0.5 L) Class I sources compared to Class 0. 100 out of the 230 protostars (43%) lack any available data in the far-infrared and submillimeter (70 μm <λ < 850 μm) and have L bol underestimated by factors of 2.5 on average, and up to factors of 8-10 in extreme cases. Correcting these underestimates for each source individually once additional data becomes available will likely increase both the mean and median of the sample by 35%-40%. We discuss and compare our results to several recent theoretical studies of protostellar luminosities and show that our new results do not invalidate the conclusions of any of these studies. As these studies demonstrate that there is more than one plausible accretion scenario that can match observations, future attention is clearly needed. The better statistics provided by our increased data set should aid such future work. © 2013. The American Astronomical Society. All rights reserved..National Science FoundationNational Aeronautics and Space AdministrationJet Propulsion Laboratory, California Institute of Technolog

Prevalence of parental supply of alcohol to minors: a systematic review

Parental supply of alcohol to minors (i.e. those under the legal drinking age) is often perceived by parents as protective against harms from drinking, despite evidence linking it with adverse alcohol-related outcomes. This systematic review describes the prevalence of parental supply of alcohol, as reported in the international literature. The review was registered with PROSPERO (CRD42020218754). We searched seven online databases (Medline, Embase, PsycINFO, CINAHL, Scopus, Web of Science and Public Health Database) and grey literature from January 2011 to December 2022 and assessed the risk of bias with the JBI Critical Appraisal Checklist. Among 58 articles included in narrative synthesis from 29 unique datasets, there was substantial variation in the definition and measurement of parental supply of alcohol. Overall prevalence rates ranged from 7.0 to 60.0% for minor-report samples, and from 24.0 to 8.0% for parent-report samples. Data indicate that parental supply prevalence is generally proportionately higher for older minors or later-stage students, for girls, and has increased over time among minors who report drinking. Literature on the prevalence of parental supply of alcohol is robust in quantity but inconsistent in quality and reported prevalence. Greater consistency in defining and measuring parental supply is needed to better inform health promotion initiatives aimed at increasing parents' awareness.Shannen van der Kruk, Nathan J. Harrison, Ashlea Bartram, Skye Newton, Caroline Miller, Robin Room, Ian Olver, and Jacqueline Bowde

States and transitions in black-hole binaries

With the availability of the large database of black-hole transients from the Rossi X-Ray Timing Explorer, the observed phenomenology has become very complex. The original classification of the properties of these systems in a series of static states sorted by mass accretion rate proved not to be able to encompass the new picture. I outline here a summary of the current situation and show that a coherent picture emerges when simple properties such as X-ray spectral hardness and fractional variability are considered. In particular, fast transition in the properties of the fast time variability appear to be crucial to describe the evolution of black-hole transients. Based on this picture, I present a state-classification which takes into account the observed transitions. I show that, in addition to transients systems, other black-hole binaries and Active Galactic Nuclei can be interpreted within this framework. The association between these states and the physics of the accretion flow around black holes will be possible only through modeling of the full time evolution of galactic transient systems.Comment: 30 pages, 11 figures, To appear in Belloni, T. (ed.): The Jet Paradigm - From Microquasars to Quasars, Lect. Notes Phys. 794 (2009

Accuracy and Stability of Computing High-Order Derivatives of Analytic Functions by Cauchy Integrals

High-order derivatives of analytic functions are expressible as Cauchy integrals over circular contours, which can very effectively be approximated, e.g., by trapezoidal sums. Whereas analytically each radius r up to the radius of convergence is equal, numerical stability strongly depends on r. We give a comprehensive study of this effect; in particular we show that there is a unique radius that minimizes the loss of accuracy caused by round-off errors. For large classes of functions, though not for all, this radius actually gives about full accuracy; a remarkable fact that we explain by the theory of Hardy spaces, by the Wiman-Valiron and Levin-Pfluger theory of entire functions, and by the saddle-point method of asymptotic analysis. Many examples and non-trivial applications are discussed in detail.Comment: Version 4 has some references and a discussion of other quadrature rules added; 57 pages, 7 figures, 6 tables; to appear in Found. Comput. Mat

Fast variability from black-hole binaries

Currently available information on fast variability of the X-ray emission from accreting collapsed objects constitutes a complex phenomenology which is difficult to interpret. We review the current observational standpoint for black-hole binaries and survey models that have been proposed to interpret it. Despite the complex structure of the accretion flow, key observational diagnostics have been identified which can provide direct access to the dynamics of matter motions in the close vicinity of black holes and thus to the some of fundamental properties of curved spacetimes, where strong-field general relativistic effects can be observed.Comment: 20 pages, 11 figures. Accepted for publication in Space Science Reviews. Also to appear in hard cover in the Space Sciences Series of ISSI "The Physics of Accretion onto Black Holes" (Springer Publisher