190 research outputs found

    Testing for rational bubbles in the presence of structural breaks: Evidence from nonstationary panels

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    This is the post-print version of the final paper published in Journal of Banking & Finance. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2011 Elsevier B.V.This paper presents new results on the rational bubbles hypothesis for a panel of 18 OECD countries using the model developed by Campbell (2000). We provide an analysis of international data that exploits increased power deriving from the panel unit root and cointegration methodology, together with the flexibility of allowing explicitly for multiple endogenous structural breaks in the individual series. Differently from the time series methodology, the panel data approach allows for a global analysis of the financial crashes that are related to rational bubbles. We find strong evidence in favor of bubbles phenomena

    Fear and Courage in Children: Two Sides of the Same Coin?

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    This study further investigated the construct of courage in children. Children aged 8–13 years (n = 51) were interviewed about the most courageous action that they had ever performed during their life, and to retrospectively rate their level of fear and courage experienced during that event. On a separate occasion, children also completed the Courage Measure for Children (CM-C) as an index of children’s general level of personal courage, as well as scales for assessing anxiety symptoms and sensation seeking. Results indicated that almost all children (i.e., 94%) indicated that they had carried out a courageous action at some point during their life, although the levels of fear and courage associated with these acts varied considerably. Further, there was no relation between fear and courage reported for the courageous action, but these variables were significantly correlated with respectively anxiety symptoms and personal courage as indexed by the CM-C. Finally, a significant positive correlation was observed between sensation seeking and personal courage, indicating that children who are more thrill and adventure seeking are generally also more courageous. It is concluded that fear and courage in children are largely unrelated and not just two sides of the same coin. The implications of these results for the etiology and treatment of childhood anxiety problems are discussed

    “You Might Belong in Gryffindor”: Children’s Courage and Its Relationships to Anxiety Symptoms, Big Five Personality Traits, and Sex Roles

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    This study describes a first exploration of the construct of courage in youths. Children aged 8–13 years were invited to report on the most courageous action that they had ever performed during their life. In addition, the Courage Measure for Children (CM-C) was construed as an index of children’s level of personal courage, and this scale was administered in two samples of school children (Ns being 168 and 159) along with a number of other questionnaires. Results indicated that children were familiar with the concept of courage as more than 70% reported to have carried out a courageous action during their life. In addition, self-reported courage as indexed by the CM-C was positively correlated with scores on a vignette measure of courage, parent ratings of children’s courage, extraversion, openness/intellect, and a masculine sex role, whereas a negative correlation was observed with anxiety symptoms. The implications of these findings and potential directions for future research are briefly discussed

    Subglacial lake drainage detected beneath the Greenland ice sheet

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    The contribution of the Greenland ice sheet to sea-level rise has accelerated in recent decades. Subglacial lake drainage events can induce an ice sheet dynamic response—a process that has been observed in Antarctica, but not yet in Greenland, where the presence of subglacial lakes has only recently been discovered. Here we investigate the water flow paths from a subglacial lake, which drained beneath the Greenland ice sheet in 2011. Our observations suggest that the lake was fed by surface meltwater flowing down a nearby moulin, and that the draining water reached the ice margin via a subglacial tunnel. Interferometric synthetic aperture radar-derived measurements of ice surface motion acquired in 1995 suggest that a similar event may have occurred 16 years earlier, and we propose that, as the climate warms, increasing volumes of surface meltwater routed to the bed will cause such events to become more common in the future

    The Sloan Digital Sky Survey-II Supernova Survey: Search Algorithm and Follow-up Observations

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    The Sloan Digital Sky Survey-II Supernova Survey has identified a large number of new transient sources in a 300 sq. deg. region along the celestial equator during its first two seasons of a three-season campaign. Multi-band (ugriz) light curves were measured for most of the sources, which include solar system objects, Galactic variable stars, active galactic nuclei, supernovae (SNe), and other astronomical transients. The imaging survey is augmented by an extensive spectroscopic follow-up program to identify SNe, measure their redshifts, and study the physical conditions of the explosions and their environment through spectroscopic diagnostics. During the survey, light curves are rapidly evaluated to provide an initial photometric type of the SNe, and a selected sample of sources are targeted for spectroscopic observations. In the first two seasons, 476 sources were selected for spectroscopic observations, of which 403 were identified as SNe. For the Type Ia SNe, the main driver for the Survey, our photometric typing and targeting efficiency is 90%. Only 6% of the photometric SN Ia candidates were spectroscopically classified as non-SN Ia instead, and the remaining 4% resulted in low signal-to-noise, unclassified spectra. This paper describes the search algorithm and the software, and the real-time processing of the SDSS imaging data. We also present the details of the supernova candidate selection procedures and strategies for follow-up spectroscopic and imaging observations of the discovered sources.Comment: Accepted for publication in The Astronomical Journal (66 pages, 13 figures); typos correcte

    First-Year Spectroscopy for the SDSS-II Supernova Survey

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    This paper presents spectroscopy of supernovae discovered in the first season of the Sloan Digital Sky Survey-II Supernova Survey. This program searches for and measures multi-band light curves of supernovae in the redshift range z = 0.05 - 0.4, complementing existing surveys at lower and higher redshifts. Our goal is to better characterize the supernova population, with a particular focus on SNe Ia, improving their utility as cosmological distance indicators and as probes of dark energy. Our supernova spectroscopy program features rapid-response observations using telescopes of a range of apertures, and provides confirmation of the supernova and host-galaxy types as well as precise redshifts. We describe here the target identification and prioritization, data reduction, redshift measurement, and classification of 129 SNe Ia, 16 spectroscopically probable SNe Ia, 7 SNe Ib/c, and 11 SNe II from the first season. We also describe our efforts to measure and remove the substantial host galaxy contamination existing in the majority of our SN spectra.Comment: Accepted for publication in The Astronomical Journal(47pages, 9 figures

    Lysyl hydroxylase 3 localizes to epidermal basement membrane and Is reduced in patients with Recessive Dystrophic Epidermolysis Bullosa

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    Recessive dystrophic epidermolysis bullosa (RDEB) is caused by mutations in COL7A1 resulting in reduced or absent type VII collagen, aberrant anchoring fibril formation and subsequent dermal-epidermal fragility. Here, we identify a significant decrease in PLOD3 expression and its encoded protein, the collagen modifying enzyme lysyl hydroxylase 3 (LH3), in RDEB. We show abundant LH3 localising to the basement membrane in normal skin which is severely depleted in RDEB patient skin. We demonstrate expression is in-part regulated by endogenous type VII collagen and that, in agreement with previous studies, even small reductions in LH3 expression lead to significantly less secreted LH3 protein. Exogenous type VII collagen did not alter LH3 expression in cultured RDEB keratinocytes and we show that RDEB patients receiving bone marrow transplantation who demonstrate significant increase in type VII collagen do not show increased levels of LH3 at the basement membrane. Our data report a direct link between LH3 and endogenous type VII collagen expression concluding that reduction of LH3 at the basement membrane in patients with RDEB will likely have significant implications for disease progression and therapeutic intervention

    The Relationship Between Therapist Effects and Therapy Delivery Factors: Therapy Modality, Dosage, and Non-completion.

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    To consider the relationships between, therapist variability, therapy modality, therapeutic dose and therapy ending type and assess their effects on the variability of patient outcomes. Multilevel modeling was used to analyse a large sample of routinely collected data. Model residuals identified more and less effective therapists, controlling for case-mix. After controlling for case mix, 5.8 % of the variance in outcome was due to therapists. More sessions generally improved outcomes, by about half a point on the PHQ-9 for each additional session, while non-completion of therapy reduced the amount of pre-post change by six points. Therapy modality had little effect on outcome. Patient and service outcomes may be improved by greater focus on the variability between therapists and in keeping patients in therapy to completion
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