1,758 research outputs found
The struggle for co-existence : communication policy by private technical standards making and its limits in unlicensed spectrum
Huge increase in the demand by the wireless sector to use the airwaves has trained focus on the classic policy problem of resource scarcity in the field. This article illuminates a
part of wireless communication – unlicensed spectrum – where a particularly fractious debate over the future usage of such space has developed between incumbent Wi-Fi interests and new entrants from the field of licensed mobile communication. The case
is novel in that private technical standards making has become a site aimed at resolving what is a contest for co-existence in unlicensed spectrum. In its conceptualisation of
private technical standards making processes as communication policy activity, the article illuminates both their affordances and limitations. It also shows the enduring utility of public regulatory steer in what are, in effect, private self-regulatory processes
aimed at creating solutions to problems with a complex socio-technical character
Heavy elements in Galactic and Magellanic Cloud HII regions: recombination-line versus forbidden-line abundances
We have obtained deep optical, long-slit spectrophotometry of the Galactic
HII regions M 17, NGC 3576 and of the Magellanic Cloud HII regions 30 Doradus,
LMC N11B and SMC N66, recording the optical recombination lines (ORLs) of CII,
NII and OII. Temperature-insensitive ORL C2+/O2+ and N2+/O2 ratios are obtained
for all nebulae except SMC N66. The ORL C2+/O2+ ratios show remarkable
agreement within each galactic system, while also being in agreement with the
corresponding CEL ratios. For all five nebulae, the O2+/H+ abundance derived
from multiple OII ORLs is found to be higher than the corresponding value
derived from the strong [OIII] 4959, 5007A CELs, by factors of 1.8--2.7 for
four of the nebulae. The LMC N11B nebula exhibits a more extreme discrepancy
factor for the O2+ ion, ~5. Thus these HII regions exhibit ORL/CEL abundance
discrepancy factors that are similar to those previously encountered amongst
planetary nebulae.
Our optical CEL O2+/H+ abundances agree to within 20-30 per cent with
published O2+/H+ abundances that were obtained from observations of infrared
fine-structure lines. Since the low excitation energies of the latter make them
insensitive to variations about typical nebular temperatures, fluctuations in
temperature are ruled out as the cause of the observed ORL/CEL O2+ abundance
discrepancies. We present evidence that the observed OII ORLs from these HII
regions originate from gas of very similar density (<3500 cm-3) to that
emitting the observed heavy-element optical and infrared CELs, ruling out
models that employ high-density ionized inclusions in order to explain the
abundance discrepancy. We consider a scenario whereby much of the heavy-element
ORL emission originates from cold (<=500 K) metal-rich ionized regions.Comment: 24 pages; 9 figures; accepted by Monthly Notices of the Royal
Astronomical Societ
Recycling bins, garbage cans or think tanks? Three myths regarding policy analysis institutes
The phrase 'think tank' has become ubiquitous – overworked and underspecified – in the political lexicon. It is entrenched in scholarly discussions of public policy as well as in the 'policy wonk' of journalists, lobbyists and spin-doctors. This does not mean that there is an agreed definition of think tank or consensual understanding of their roles and functions. Nevertheless, the majority of organizations with this label undertake policy research of some kind. The idea of think tanks as a research communication 'bridge' presupposes that there are discernible boundaries between (social) science and policy. This paper will investigate some of these boundaries. The frontiers are not only organizational and legal; they also exist in how the 'public interest' is conceived by these bodies and their financiers. Moreover, the social interactions and exchanges involved in 'bridging', themselves muddy the conception of 'boundary', allowing for analysis to go beyond the dualism imposed in seeing science on one side of the bridge, and the state on the other, to address the complex relations between experts and public policy
Delivering reform in English healthcare: an ideational perspective
A variety of perspectives has been put forward to understand reform across healthcare systems. Recently, some have called for these perspectives to give greater recognition to the role of ideational processes. The purpose of this article is to present an ideational approach to understanding the delivery of healthcare reform. It draws on a case of English healthcare reform – the Next Stage Review led by Lord Darzi – to show how the delivery of its reform proposals was associated with four ideational frames. These frames built on the idea of “progress” in responding to existing problems; the idea of “prevailing policy” in forming part of a bricolage of ideas within institutional contexts; the idea of “prescription” as top-down structural change at odds with local contexts; and the idea of “professional disputes” in challenging the notion of clinical engagement across professional groups. The article discusses the implications of these ideas in furthering our understanding of policy change, conflict and continuity across healthcare settings
Chemical evolution of the Small Magellanic Cloud based on planetary nebulae
We investigate the chemical evolution of the Small Magellanic Cloud (SMC)
based on abundance data of planetary nebulae (PNe). The main goal is to
investigate the time evolution of the oxygen abundance in this galaxy by
deriving an age-metallicity relation. Such a relation is of fundamental
importance as an observational constraint of chemical evolution models of the
SMC. We have used high quality PNe data in order to derive the properties of
the progenitor stars, so that the stellar ages could be estimated. We collected
a large number of measured spectral fluxes for each nebula, and derived
accurate physical parameters and nebular abundances. New spectral data for a
sample of SMC PNe obtained between 1999 and 2002 are also presented. These data
are used together with data available in the literature to improve the accuracy
of the fluxes for each spectral line. We obtained accurate chemical abundances
for PNe in the Small Magellanic Cloud, which can be useful as tools in the
study of the chemical evolution of this galaxy and of Local Group galaxies. We
present the resulting oxygen versus age diagram and a similar relation
involving the [Fe/H] metallicity based on a correlation with stellar data. We
discuss the implications of the derived age-metallicity relation for the SMC
formation, in particular by suggesting a star formation burst in the last 2-3
Gyr.Comment: 11 pages, 6 figures, accepted for publication in Astronomy and
Astrophysic
Preferences and skills of Indian public sector teachers
With a sample of 700 future public sector primary teachers in India, a Discrete Choice Experiment is used to measure job preferences, particularly regarding location. General skills are also tested. Urban origin teachers and women are more averse to remote locations than rural origin teachers and men respectively. Women would require a 26-73 percent increase in salary for moving to a remote location. The results suggest that existing caste and gender quotas can be detrimental for hiring skilled teachers willing to work in remote locations. The most preferred location is home, which supports decentralised hiring, although this could compromise skills
Public Managers, Media Influence, and Governance: Three Research Traditions Empirically Explored
Nowadays, media and media logic have become important and inherent elements in everyday practices of public administration and policy making. However, the logic of the media is often very different from, and conflicting with, the logic of political and administrative life. So the question of how public managers experience and deal with media attention is more relevant than ever. An analytical sketch of the literature on the relationship between public managers and media provides three main categories of literature (public relations, agenda, and mediatization tradition). These three categories are used to develop statements (so-called Q-sort statements) to capture the way public managers experience thei
Volunteering in the care of people with severe mental illness: a systematic review
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
Improving Predictions for Helium Emission Lines
We have combined the detailed He I recombination model of Smits with the
collisional transitions of Sawey & Berrington in order to produce new accurate
helium emissivities that include the effects of collisional excitation from
both the 2 (3)S and 2 (1) S levels. We present a grid of emissivities for a
range of temperature and densities along with analytical fits and error
estimates.
Fits accurate to within 1% are given for the emissivities of the brightest
lines over a restricted range for estimates of primordial helium abundance. We
characterize the analysis uncertainties associated with uncertainties in
temperature, density, fitting functions, and input atomic data. We estimate
that atomic data uncertainties alone may limit abundance estimates to an
accuracy of 1.5%; systematic errors may be greater than this. This analysis
uncertainty must be incorporated when attempting to make high accuracy
estimates of the helium abundance. For example, in recent determinations of the
primordial helium abundance, uncertainties in the input atomic data have been
neglected.Comment: ApJ, accepte
- …
