4,768 research outputs found

    On the photometric behaviour of the Pleiades K dwarf HII 1883

    Get PDF
    Photometric data from a variety of sources have been analysed to check if effects of differential rotation or evolutionary spin-down can be detected in HII 1883. Although the same light- curve form may be maintained for several years, shape changes and phase shifts do not allow sufficiently long time-bases for the required accuracy of period determination. One form of light-curve may have a tendency to recur with phase coherence. Using this observation allows determination of three potentially more accurate periods relative to the one previously established, but the choice of any revised value is subject to imprecise knowledge of the integer number of cycles over the time-base. The phase-locked tendency, if confirmed, requires some mechanism for spots to recur at a given longitude. A suggestion of the star being a magnetic oblique rotator is mooted but other observational and theoretical support would be required to promote this notion further. Evidence of small short-term changes occurring over just a few periods is explored. Comparison of the contemporaneous light- curve with the H α line emission RV variations reveals a phase difference of 90°, so making a connection that the disturbances producing the photometric signals have the same location as those generating at least some part of the H α emission. Finally a multi-spot model is presented to mimic the observed light-curves

    High-resolution Near-Infrared Images and Models of the Circumstellar Disk in HH 30

    Get PDF
    We present Hubble Space Telescope (HST) Near-Infrared Camera and Multi-object Spectrometer (NICMOS) observations of the reflection nebulosity associated with the T Tauri star HH 30. The images show the scattered light pattern characteristic of a highly inclined, optically thick disk with a prominent dustlane whose width decreases with increasing wavelength. The reflected nebulosity exhibits a lateral asymmetry in the upper lobe on the opposite side to that reported in previously published Wide Field Planetary Camera 2 (WFPC2) images. The radiation transfer model which most closely reproduces the data has a flared accretion disk with dust grains larger than standard interstellar medium grains by a factor of approximately 2.1. A single hotspot on the stellar surface provides the necessary asymmetry to fit the images and is consistent with previous modeling of the light curve and images. Photometric analysis results in an estimated extinction of Av>~80; however, since the photometry measures only scattered light rather than direct stellar flux, this a lower limit. The radiative transfer models require an extinction of Av = 7,900.Comment: Accepted for publication in Ap.

    On the functional anatomy of the urge-for-action

    Get PDF
    Several common neuropsychiatric disorders (e.g., obsessive-compulsive disorder, Tourette syndrome (TS), autistic spectrum disorder) are associated with unpleasant bodily sensations that are perceived as an urge for action. Similarly, many of our everyday behaviors are also characterized by bodily sensations that we experience as urges for action. Where do these urges originate? In this paper, we consider the nature and the functional anatomy of “urges-for-action,” both in the context of everyday behaviors such as yawning, swallowing, and micturition, and in relation to clinical disorders in which the urge-for-action is considered pathological and substantially interferes with activities of daily living (e.g., TS). We review previous frameworks for thinking about behavioral urges and demonstrate that there is considerable overlap between the functional anatomy of urges associated with everyday behaviors such as swallowing, yawning, and micturition, and those urges associated with the generation of tics in TS. Specifically, we show that the limbic sensory and motor regions—insula and mid-cingulate cortex—are common to all of these behaviors, and we argue that this “motivation-for-action” network should be considered distinct from an “intentional action” network, associated with regions of premotor and parietal cortex, which may be responsible for the perception of “willed intention” during the execution of goal-directed actions

    The EBLM Project I-Physical and orbital parameters, including spin-orbit angles, of two low-mass eclipsing binaries on opposite sides of the Brown Dwarf limit

    Get PDF
    This paper introduces a series of papers aiming to study the dozens of low mass eclipsing binaries (EBLM), with F, G, K primaries, that have been discovered in the course of the WASP survey. Our objects are mostly single-line binaries whose eclipses have been detected by WASP and were initially followed up as potential planetary transit candidates. These have bright primaries, which facilitates spectroscopic observations during transit and allows the study of the spin-orbit distribution of F, G, K+M eclipsing binaries through the Rossiter-McLaughlin effect. Here we report on the spin-orbit angle of WASP-30b, a transiting brown dwarf, and improve its orbital parameters. We also present the mass, radius, spin-orbit angle and orbital parameters of a new eclipsing binary, J1219-39b (1SWAPJ121921.03-395125.6, TYC 7760-484-1), which, with a mass of 95 +/- 2 Mjup, is close to the limit between brown dwarfs and stars. We find that both objects orbit in planes that appear aligned with their primaries' equatorial planes. Neither primaries are synchronous. J1219-39b has a modestly eccentric orbit and is in agreement with the theoretical mass--radius relationship, whereas WASP-30b lies above it.Comment: 12 pages, 7 figures, data in appendices, submitted to A&A (taking in account 1st referee report

    The United Kingdoms Eurosceptic political economy

    Get PDF
    This article explores how a political economy approach can explicate recent events in the United Kingdom’s relation to the European Union. The proposition is that neither critical nor comparative approaches do justice to the extent to which British elites have sought to differentiate the UK from the EU. The UK is here understood as a Eurosceptic political economy, constructed in opposition to European integration and, in particular, Economic and Monetary. The article explores how we have witnessed a hardening of this Eurosceptic political economy in the context of the Eurozone crisis. The most distinctive feature of which, as seen in the referendum campaign, is the extent to which the economic case for withdrawal has been established as part of the mainstream of British political debate

    The revitalised Fonofale as a research paradigm: A perspective on Pacific sexuality and reproduction research

    Get PDF
    Research into Pacific peoples’ sexuality and reproduction is often complex and conflicts with social tapu. Historically, Pacific sexuality and reproduction research had been approached using a deficits-based lens with minimal congruence of Pacific cultural values. We offer a revitalised Fonofale model (Pulotu-Endemann, 1995) as a research paradigm that centres tapu in all considerations and decisions surrounding the research. This revitalised model offers a strengths-based approach that can promote valuable collection of, and meaningful engagement with data. We offer a case study which utilised this research paradigm as an overarching strategy. Te Tīpani Project was a mixed methods investigation into eighty-two Pacific tertiary students’ understandings of sexuality and reproduction. Pacific research methods and methodologies, including the Kakala model and Talanoa method supported the integration of the paradigm into components of the study. We encourage researchers to utilise this strategy to fulfil their research obligations, as facilitators and guardians (mana tiaki) of the research environment. Pacific research methods, methodologies and epistemologies hold an important place in the field of sensitive Pacific well-being research by enabling cultural consideration and responsiveness

    Memorial meshwork: the making of the commemorative space of the Hyde Park 7/7 memorial

    Get PDF
    How do memorials act to transmit memory through the organization of space? In this paper we contrast a ‘preservation’ model of the endurance of encoded memory with a ‘meshwork’ model which treats memory as emergent on the perdurance of the memorial site. Developing a theoretical framework from Tim Ingold’s (2011; 2013) work, we describe how memorialization receives its spatial form through a collective work of braiding together multiple threads of activities and material flows. To illustrate, we examine the spatial and temporal organization of the Hyde Park 7/7 memorial from its initial designs, through to installation and contemporary use. We draw on interview data featuring various stakeholders in the 7/7 memorial project to analyse the relationship between memorial space and material relations. We develop an approach to organizational space as an unfinished meshwork that folds together wanted and unwanted memory, making the historical a matter of ongoing live concern but with the absence of a permanent guiding narrative

    Intercultural ethics: questions of methods in language and intercultural communication

    Get PDF
    This paper explores how questions of ethics and questions of method are intertwined and unavoidable in any serious study of language and intercultural communication. It argues that the focus on difference and solution orientations to intercultural conflict has been a fundamental driver for theory, data collection and methods in the field. These approaches, the paper argues, have created a considerable consciousness raising industry, with methods, trainings and ‘critical incidents’, which ultimately focus intellectual energy in areas which may be productive in terms of courses and publications but which have a problematic basis in their ethical terrain. Dieser Artikel untersucht wie ethische und methodische Fragen nicht nur ineinander greifen, sondern in keiner ernstzunehmenden Studie ueber Sprache und interkulturelle Kommunikation ausgelassen werden duerfen. Es wird hier argumentiert, dass der Schwerpunkt auf Verschiedenheit und Problemorientierung im interkulturellen Konflikt einen wesentlichen Einfluss auf theoretische Entwicklungen, Datenerhebung und Methoden in diesem Bereich hatte. Dieser Artikel legt auch dar, wie diese Ansaetze eine betraechtliche ‘Bewusstseinsbildungs – Branche' erzeugt haben, mit Methoden, Trainings, und ‘kritischen Interaktionssituationen’, welche letztendlich allen intellektuellen Arbeitseifer auf Bereiche konzentriert hat, die zwar ertragreich sind in Bezug auf Kurse und Publikationen, jedoch eine problematische Grundlage im ethischen Bereich aufweisen
    • 

    corecore