56,606 research outputs found
Thermonuclear burst oscillations
Burst oscillations, a phenomenon observed in a significant fraction of Type I
(thermonuclear) X-ray bursts, involve the development of highly asymmetric
brightness patches in the burning surface layers of accreting neutron stars.
Intrinsically interesting as nuclear phenomena, they are also important as
probes of dense matter physics and the strong gravity, high magnetic field
environment of the neutron star surface. Burst oscillation frequency is also
used to measure stellar spin, and doubles the sample of rapidly rotating (above
10 Hz) accreting neutron stars with known spins. Although the mechanism remains
mysterious, burst oscillation models must take into account thermonuclear flame
spread, nuclear processes, rapid rotation, and the dynamical role of the
magnetic field. This review provides a comprehensive summary of the
observational properties of burst oscillations, an assessment of the status of
the theoretical models that are being developed to explain them, and an
overview of how they can be used to constrain neutron star properties such as
spin, mass and radius.Comment: Preprint of article submitted to Annual Reviews of Astronomy and
Astrophysics (2012). 35 page
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Goodbye to Projects? A livelihoods-grounded audit of Community-Based Planning Project in South Africa
Approaches to projects and development have undergone considerable change in the last decade with significant policy shifts on governance, gender, poverty eradication, and environmental issues. Most recently this has led to the adoption and promotion of the sustainable livelihood (SL) approach. The adoption of the SL approach presents challenges to development interventions including: the future of projects and programmes, and sector wide approaches (SWAPs) and direct budgetary support. This paper `A livelihoods-grounded audit of the Community-Based Planning (CBP) Project in South Africa¿ is the sixth in the series of project working papers.Department for International Developmen
Constraining the neutron star equation of state using Pulse Profile Modeling
One very promising technique for measuring the dense matter Equation of State
exploits hotspots that form on the neutron star surface due to the pulsar
mechanism, accretion streams, or during thermonuclear explosions in the neutron
star ocean. This article explains how Pulse Profile Modeling of hotspots is
being used by the Neutron Star Interior Composition Explorer (NICER), an X-ray
telescope installed on the International Space Station in 2017 - and why the
technique is a mission driver for the next, larger-area generation of
telescopes including the enhanced X-ray Timing and Polarimetry (eXTP) mission
and the Spectroscopic Time-Resolving Observatory for Broadband Energy X-rays
(STROBE-X).Comment: To appear in the AIP Conference Proceedings of the Xiamen-CUSTIPEN
Workshop on the EOS of Dense Neutron-Rich Matter in the Era of Gravitational
Wave Astronomy (January 3 - 7, 2019, Xiamen, China
The “Kaleidoscope of Life”: Story as Vital for Values Education
Educators and the general American public continue to favor character education programs in public schools, but many are unsure how best to teach values. Currently, and in the past, literature-based approaches to character education have received advocacy because of the values stories contain and because of the nature of story itself. Story is universal and uniquely character-molding and is a time-honored method to fostering understanding. This fact can be gleamed in religious and secular traditions alike, having been used and advocated by as wide array of individuals as Jesus Christ and N. Scott Momaday. Numerous bases—spiritual, historical, psychological, and philosophical—exist for using story. Stories are powerful, emotionally provocative, and effective not only in exploring the meaning of various values, but also in providing particular benefits, such as organizing ideas or enhancing awareness. For these reasons, literature-based approaches to character education can become the ideal foundation for imparting an understanding of universally esteemed values and building character traits
Foreground removal for Square Kilometre Array observations of the Epoch of Reionization with the Correlated Component Analysis
We apply the Correlated Component Analysis (CCA) method on simulated data of
the Square Kilometre Array, with the aim of accurately cleaning the 21 cm
reionization signal from diffuse foreground contamination. The CCA has been
developed for the Cosmic Microwave Background, but the application of the
Fourier-domain implementation of this method to the reionization signal is
straightforward.
The CCA is a parametric method to estimate the frequency behaviour of the
foregrounds from the data by using second-order statistics. We test its
performance on foreground simulations of increasing complexity, designed to
challenge the parametric models adopted. We also drop the assumption of
spectral smoothness that most of the methods rely upon. We are able to clean
effectively the simulated data across the explored frequency range (100-200
MHz) for all the foreground simulations. This shows that the CCA method is very
promising for EoR component separation.Comment: 12 pages, 15 figures, accepted by MNRA
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Designing persuasive games through competition
This case study describes a game design competition that was influenced by participatory design. We consider how successful our approach was and discuss the tensions that arose during the design and evaluation process
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Goodbye to Projects? - Review of development interventions in Tanzania: From projects to livelihoods approaches
Approaches to projects and development have undergone considerable change in the last decade with significant policy shifts on governance, gender, poverty eradication, and environmental issues. Most recently this has led to the adoption and promotion of the sustainable livelihood (SL) approach. The adoption of the SL approach presents challenges to development interventions including: the future of projects and programmes, and sector wide approaches (SWAPs) and direct budgetary support. This paper `A Review of Approaches to Development Interventions in Tanzania: From Projects to Livelihood Approaches¿ is the third in the series of the project working papers. This is the output of a literature review and semi-structured interviewing in Tanzania.Department for International Developmen
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Goodbye to Projects? Working paper 1: Annotated bibliography on livelihood approaches and development interventions.
YesThis paper is one in a series of working papers prepared under a research project on Goodbye to Projects? The Institutional Impacts of a Livelihood Approach on Projects and Project Cycle Management.
This is a collaborative project between the Bradford Centre for International Centre for Development (BCID) with the Economic and Policy Research Centre (EPRC), Uganda; Khanya ¿ managing rural change, South Africa; and, the Institute for Development Management (IDM), Tanzania. The project is supported by the UK Department for International Development (DFID) under their Economic and Social Research Programme (ESCOR).Department for International Developmen
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