4,966 research outputs found
A Strong Upper Limit on the Pulsed Radio Luminosity of the Compact Object 1RXS J141256.0+792204
The ROSAT X-ray source 1RXS J141256.0+792204 has recently been identified as
a likely compact object whose properties suggest it could be a very nearby
radio millisecond pulsar at d = 80 - 260pc. We investigated this hypothesis by
searching for radio pulsations using the Westerbork Synthesis Radio Telescope.
We observed 1RXS J141256.0+792204 at 385 and 1380MHz, recording at high time
and frequency resolution in order to maintain sensitivity to millisecond
pulsations. These data were searched both for dispersed single pulses and using
Fourier techniques sensitive to constant and orbitally modulated periodicities.
No radio pulsations were detected in these observations, resulting in pulsed
radio luminosity limits of L_400 ~ 0.3 (d/250pc)^2 mJy kpc^2 and L_1400 ~ 0.03
(d/250pc)^2 mJy kpc^2 at 400 and 1400MHz respectively. The lack of detectable
radio pulsations from 1RXS J141256.0+792204 brings into question its
identification as a nearby radio pulsar, though, because the pulsar could be
beamed away from us, this hypothesis cannot be strictly ruled out.Comment: To appear in A&A. 3 page
Public Participation Organizations and Open Policy:A Constitutional Moment for British Democracy?
This article builds on work in Science and Technology Studies and cognate disciplines concerning the institutionalization of public engagement and participation practices. It describes and analyses ethnographic qualitative research into one âorganization of participation,â the UK governmentâfunded Sciencewise program. Sciencewiseâs interactions with broader political developments are explored, including the emergence of âopen policyâ as a key policy object in the UK context. The article considers what the new imaginary of openness means for institutionalized forms of public participation in science policymaking, asking whether this is illustrative of a âconstitutional momentâ in relations between society and science policymaking
Scapegoat: John Dewey and the character education crisis
Many conservatives, including some conservative scholars, blame the ideas and influence of John Dewey for what has frequently been called a crisis of character, a catastrophic decline in moral behavior in the schools and society of North America. Deweyâs critics claim that he is responsible for the undermining of the kinds of instruction that could lead to the development of character and the strengthening of the will, and that his educational philosophy and example exert a ubiquitous and disastrous influence on studentsâ conceptions of moral behavior. This article sets forth the views of some of these critics and juxtaposes them with what Dewey actually believed and wrote regarding character education. The juxtaposition demonstrates that Dewey neither called for nor exemplified the kinds of character-eroding pedagogy his critics accuse him of championing; in addition, this paper highlights the ways in which Dewey argued consistently and convincingly that the pedagogical approaches advocated by his critics are the real culprits in the decline of character and moral education
It would be a Pleasure : Augmented Reality and Engagement in a Heritage Context
The interchangeability, confusion and conflict of what constitutes audience engagement has a long history, with much disagreement concerning boundaries and definitions. Dewey states that it is a mistake to see the artist as active and the audience as purely passive, and argues that âthe active engagement of the audience is required to fully realise any workâ (Dewey 1934). This predates the notions of âinteractiveâ or âparticipatoryâ as understood today, but highlights the longstanding appreciation of the role the audience plays in the consumption of artworks. A sentiment echoed by Duchamp (1957) stating that âthe spectator adds his contribution to the creative actâ.
The research project presented at EVA 2017 seeks to offer a model for engagement, that of pleasure, which explores methods to motivate active participation
Polymer Induced Bundling of F-actin and the Depletion Force
The inert polymer polyethylene glycol (PEG) induces a "bundling" phenomenon
in F-actin solutions when its concentration exceeds a critical onset value C_o.
Over a limited range of PEG molecular weight and ionic strength, C_o can be
expressed as a function of these two variables. The process is reversible, but
hysteresis is also observed in the dissolution of the bundles, with ionic
strength having a large influence. Additional actin filaments are able to join
previously formed bundles. Little, if any, polymer is associated with the
bundle structure.
Continuum estimates of the Asakura-Oosawa depletion force, Coulomb repulsion,
and van der Waals potential are combined for a partial explanation of the
bundling effect and hysteresis. Conjectures are presented concerning the
apparent limit in bundle size
Critical Micronutrients in Pregnancy, Lactation, and Infancy: Considerations on Vitamin D, Folic Acid, and Iron, and Priorities for Future Research
The Early Nutrition Academy and the European Commission-funded EURRECA Network of Excellence jointly sponsored a scientific workshop on critical micronutrients in pregnancy, lactation, and infancy. Current knowledge and unresolved questions on the supply of vitamin D, folic acid, and iron for pregnant women, lactating women, and infants, and their health effects were discussed. The question was addressed of whether, and under which circumstances, supplementation with these micronutrients in addition to usual dietary intakes is advisable. The workshop participants concluded that public health strategies for improving supplementation with these micronutrients in pregnancy, lactation, and infancy are required. Further research priorities should focus on adequately powered human intervention trials to obtain a stronger evidence base for the amounts of vitamin D, folic acid, and iron that have optimal effects on health. The conclusions of the workshop should help to inform the scientific community as well as public health policy strategies. Copyright (C) 2011 S. Karger AG, Base
Comprehension as social and intellectual practice: Rebuilding curriculum in low socioeconomic and cultural minority schools
This article reframes the concept of comprehension as a social and intellectual practice. It reviews current approaches to reading instruction for linguistically and culturally diverse and low socioeconomic students, noting an emphasis on comprehension as autonomous skills. The Four Resources model (Freebody & Luke, 1990) is used to make the case for the integration of comprehension instruction with an emphasis on student cultural and community knowledge, and substantive intellectual and sociocultural content in elementary school curricula. Illustrations are drawn from research underway on the teaching of literacy in primary schools in low SES communities
Decentring emotion regulation: from emotion regulation to relational emotion
YesThis article takes a critical approach to emotion regulation suggesting that the concept needs supplementing with a relational position on the generation and restraint of emotion. I chart the relational approach to emotion, challenging the âtwo-stepâ model of emotion regulation. From this, a more interdisciplinary approach to emotion is developed using concepts from social science to show the limits of instrumental, individualistic and cognitivist orientations in the psychology of emotion regulation, centred on appraisal theory. Using a social interactionist approach I develop an ontological position in which social relations form the fundamental contexts in which emotions are generated, toned, and restrained, so that regulation is decentred and seen as just one moment or aspect in the relational patterning of emotion
Age constraints in the double pulsar system J0737-3039
We investigate the age constraints that can be placed on the double pulsar
system using models for the spin-down of the first-born 22.7-ms pulsar A and
the 2.77-s pulsar B with characteristic ages of 210 and 50 Myr respectively.
Standard models assuming dipolar spin-down of both pulsars suggest that the
time since the formation of B is ~50 Myr, i.e. close to B's characteristic age.
However, adopting models which account for the impact of A's relativistic wind
on B's spin-down we find that the formation of B took place either 80 or 180
Myr ago, depending the interaction mechanism. Formation 80 Myr ago, closer to
B's characteristic age, would result in the contribution from J0737-3039 to the
inferred coalescence rates for double neutron star binaries increasing by 40%.
The 180 Myr age is closer to A's characteristic age and would be consistent
with the most recent estimates of the coalescence rate. The new age constraints
do not significantly impact recent estimates of the kick velocity, tilt angle
between pre and post-supernova orbital planes or pre-supernova mass of B's
progenitor.Comment: 5 pages, 2 figures, 1 table, accepted for publication by MNRA
A gamma- and X-ray detector for cryogenic, high magnetic field applications
As part of an experiment to measure the spectrum of photons emitted in
beta-decay of the free neutron, we developed and operated a detector consisting
of 12 bismuth germanate (BGO) crystals coupled to avalanche photodiodes (APDs).
The detector was operated near liquid nitrogen temperature in the bore of a
superconducting magnet and registered photons with energies from 5 keV to 1000
keV. To enlarge the detection range, we also directly detected soft X-rays with
energies between 0.2 keV and 20 keV with three large area APDs. The
construction and operation of the detector is presented, as well as information
on operation of APDs at cryogenic temperatures
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