5,740 research outputs found
StuckâŠin This Place: Shrinking Policy Space in New Brunswick
After New Brunswickâs 2010 provincial election, a new policy environment took shape, characterized by an awareness of, among other things, ballooning public debt, economic dysfunction, soaring health costs, and demographic decline. Employing institutionalist analysis, this essay canvasses these problems and examines the obstacles standing in the way of effective, concerted action to deal with them. New Brunswick manifests several factors making institutional change to address these policy challenges difficult.RĂ©sumĂ©AprĂšs les Ă©lections du Nouveau-Brunswick de 2010, un nouvel environnement politique a pris forme. Cet environnement a Ă©tĂ© caractĂ©risĂ© par une prise de conscience, entres autres, dâune dette publique astronomique, dâune Ă©conomie dysfonctionnelle, de coĂ»ts de soins de santĂ© qui montent en flĂšche et dâun dĂ©clin de la dĂ©mographie. En sâappuyant sur une analyse institutionnaliste, cet article sonde ces problĂšmes et examine les obstacles qui freinent les actions efficaces et concertĂ©es nĂ©cessaires afin de les surmonter. Le Nouveau-Brunswick prĂ©sente plusieurs facteurs qui contribuent aux changements institutionnels afin de traiter de ces dĂ©fis politiques difficiles
Evaluation of wood pretreatments on oak and cedar
In a separate study, we conducted a series of high-precision radiocarbon measurements using wood from Britain and New Zealand to investigate interhemispheric offsets and possible temporal variations. To minimize variability associated with different species, the pretreatment of the oak (Quercus patraea) and cedar (Librocedrus bidwilli) was to acellulose for both. This study investigates the thoroughness of a range of pretreatment processes by the stable isotope analysis of the products
Surface flashover of oil-immersed dielectric materials in uniform and non-uniform fields
The applied electrical fields required to initiate surface flashover of different types of dielectric material immersed in insulating oil have been investigated, by applying impulses of increasing peak voltage until surface flashover occurred. The behavior of the materials in repeatedly over-volted gaps was also analyzed in terms of breakdown mode (some bulk sample breakdown behaviour was witnessed in this regime), time to breakdown, and breakdown voltage. Cylindrical samples of polypropylene, low-density polyethylene, ultra-high molecular weight polyethylene, and Rexolite, were held between two electrodes immersed in insulating oil, and subjected to average applied electrical fields up to 870 kV/cm. Tests were performed in both uniform- and non-uniform-fields, and with different sample topologies. In applied field measurements, polypropylene required the highest levels of average applied field to initiate flashover in all electrode configurations tested, settling at similar to 600 kV/cm in uniform fields, and similar to 325 kV/cm in non-uniform fields. In over-volted point-plane gaps, ultra-high molecular weight polyethylene exhibited the longest pre-breakdown delay times. The results will provide comparative data for system designers for the appropriate choice of dielectric materials to act as insulators for high-voltage, pulsed-power machines
The suitability of N2 to replace SF6 in a triggered spark-gap switch for pulsed power applications
The high dielectric strength of sulphur hexafluoride (SF6) when compared with other gases, coupled with safety benefits such as non-flammability and non-toxicity, has seen the widespread use of SF6 for the insulation of switching components. However, SF6 is now widely recognised as a highly damaging greenhouse gas, and investigations of the switching properties of alternative gases to replace SF6 within the bounds of existing system topologies are required. In the present paper, a comparative study has been carried out on a triggered spark-gap of type presently deployed in industrial pulsed-power machines, to determine the suitability of nitrogen (N2) to replace SF6 as the switching medium, without compromising on functionality. Experiments were performed with fast-rising trigger pulses to minimise the delay time to breakdown and jitter, and three distinct operational regimes have been identified for both gases as the pressure inside the switch is increased. The static breakdown characteristics and upper pressure boundaries of operation have been determined for both gases at a range of dc charging voltages. Measurements of the time to breakdown have shown jitters as low as 1.3 ns when operating in N2, highlighting the potential of N2 to replace SF6 without the need for re-design or replacement of the presently used switch
Effective sigma models and lattice Ward identities
We perform a lattice analysis of the Faddeev-Niemi effective action
conjectured to describe the low-energy sector of SU(2) Yang-Mills theory. To
this end we generate an ensemble of unit vector fields ("color spins") n from
the Wilson action. The ensemble does not show long-range order but exhibits a
mass gap of the order of 1 GeV. From the distribution of color spins we
reconstruct approximate effective actions by means of exact lattice
Schwinger-Dyson and Ward identities ("inverse Monte Carlo"). We show that the
generated ensemble cannot be recovered from a Faddeev-Niemi action, modified in
a minimal way by adding an explicit symmetry-breaking term to avoid the
appearance of Goldstone modes.Comment: 25 pages, 17 figures, JHEP styl
Dating placentalia: Morphological clocks fail to close the molecular fossil gap
Dating the origin of Placentalia has been a contentious issue for biologists and paleontologists. Although it is likely that crowngroup
placentals originated in the Late Cretaceous, nearly all molecular clock estimates point to a deeper Cretaceous origin. An
approach with the potential to reconcile this discrepancy could be the application of a morphological clock. This would permit
the direct incorporation of fossil data in node dating, and would break long internal branches of the tree, so leading to improved
estimates of node ages. Here, we use a large morphological dataset and the tip-calibration approach of MrBayes. We find that the
estimated date for the origin of crown mammals is much older, 130â145 million years ago (Ma), than fossil and molecular clock
data (80â90 Ma). Our results suggest that tip calibration may result in estimated dates that are more ancient than those obtained
from other sources of data. This can be partially overcome by constraining the ages of internal nodes on the tree; however, when
this was applied to our dataset, the estimated dates were still substantially more ancient than expected. We recommend that
results obtained using tip calibration, and possibly morphological dating more generally, should be treated with caution
Land Use Changes in Europe. Processes of Change, Environmental Transformations and Future Patterns
Patterns of land use in Europe owe much to the boundaries set by the natural environment. The alterations imposed by man are still ultimately constrained by natural limitations of which climate pays a major role. Possible global climatic change, therefore, is likely to have a major effect on land use patterns and this is the first volume to describe the potential changes against the background of historical land use changes in Europe, the likely future land use patterns and the policy implications that are becoming evident in relation to feasible land use management strategies.
This book covers a wide spectrum of issues: How will the characteristics of the land resource change? What are the implications of these changes on the environment? What policies need to be introduced to encourage sensitivity to environmental supply limitations? What is the scale of response that is needed to address these issues?
The workshop that addressed these topics was sponsored by IIASA in association with the Institute of Geography and Spatial Organization of the Polish Academy of Sciences. The Stockholm Environment Institute collaborated in this and took on the main responsibility of producing this volume from the range of contributions at the workshop
Transportation and Urban Performance: Accessibility, Daily Mobility and Location of Households and Facilities
This chapter presents a conceptual framework for studying
urban performance from a transportation perspective in effort to
identify and define research issues and concepts related to urban
performance. A key concept in this framework is accessibility, which
is defined and analysed in section 'Infrastructure, Accessibility and
Reach'. In general, accessibility refers to the ability to visit activity
places (shops, work places, services etc.) by using a particular
transport system at an acceptable cost in terms of time or mone
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