6,148 research outputs found
Regulatory Reform and the National Energy Board
Government regulation has been increasing rapidly for the past five decades. At present, boards, commissions, and other variously named administrative agencies pervade nearly every phrase of the nation\u27s economic and social activity. At the federal level, these groups are involved in formulating economic policy; they control the construction and operation of pipelines and other means of transport; they supervise most facets of the telecommunications and broadcasting industries; they regulate, in many ways, the exploration for and manufacturing and marketing of raw materials. At the provincial level, they are concerned with labour relations, education, and the use of property. In addition, an assortment of fire marshalls, engineers, inspectors, and registrars are among those who operate under municipal ordinances to maintain property according to certain guidelines, to regulate how and where structures will be built and maintained and, in many circumstances, to control how, when, and where individuals may operate businesses
Conformational Mechanics of Polymer Adsorption Transitions at Attractive Substrates
Conformational phases of a semiflexible off-lattice homopolymer model near an
attractive substrate are investigated by means of multicanonical computer
simulations. In our polymer-substrate model, nonbonded pairs of monomers as
well as monomers and the substrate interact via attractive van der Waals
forces. To characterize conformational phases of this hybrid system, we analyze
thermal fluctuations of energetic and structural quantities, as well as
adequate docking parameters. Introducing a solvent parameter related to the
strength of the surface attraction, we construct and discuss the
solubility-temperature phase diagram. Apart from the main phases of adsorbed
and desorbed conformations, we identify several other phase transitions such as
the freezing transition between energy-dominated crystalline low-temperature
structures and globular entropy-dominated conformations.Comment: 13 pages, 15 figure
Co-axial dual-core resonant leaky fibre for optical amplifiers
We present a co-axial dual-core resonant leaky optical fibre design, in which
the outer core is made highly leaky. A suitable choice of parameters can enable
us to resonantly couple power from the inner core to the outer core. In a
large-core fibre, such a resonant coupling can considerably increase the
differential leakage loss between the fundamental and the higher order modes
and can result in effective single-mode operation. In a small-core single-mode
fibre, such a coupling can lead to sharp increase in the wavelength dependent
leakage loss near the resonant wavelength and can be utilized for the
suppression of amplified spontaneous emission and thereby gain equalization of
an optical amplifier. We study the propagation characteristics of the fibre
using the transfer matrix method and present an example of each, the
large-mode-area design for high power amplifiers and the wavelength tunable
leakage loss design for inherent gain equalization of optical amplifiers.Comment: 6 page
Mismatch of corneal specialists' expectations and keratoconus knowledge in general ophthalmologists: A prospective observational study in Switzerland
Eruption of Shallow Crystal Cumulates during Explosive Phonolitic Eruptions on Tenerife, Canary Islands
The recent eruptive history on the island of Tenerife is characterized in part by the presence of zoned phonolitic ignimbrites, some of which prominently display two types of juvenile clasts (i.e. light-colored, aphyric pumices alongside darker, more crystal-rich pumices, here dubbed ‘crystal-poor' and ‘crystal-rich', respectively). Petrographic observation of the crystal-rich pumices reveals intensely resorbed and intergrown mineral textures, consistent with the system reaching a high crystallinity, followed by perturbation and remobilization prior to eruption. Some trace elements show anomalous concentrations in such crystal-rich pumices (e.g. bulk Ba > 2000 ppm alongside low Zr and a positive Eu anomaly) indicative of crystal accumulation (of feldspar ± biotite). Many biotite and feldspar crystals are reversely zoned, with rim concentrations that are high in Ba but low in Sr, implying crystallization from an ‘enriched' melt, potentially derived from remobilization by partial melting of the aforementioned cumulate zones. Given (1) the presence of cumulates in the eruptive record on Tenerife and a bimodality of pumice textures, (2) the presence of three dominant compositions (basanite, phonotephrite, phonolite, separated by compositional gaps) in the volcanic record, and (3) abundant support for crystal fractionation as the dominant drive for magmatic evolution in Tenerife, it is hypothesized that crystal-poor magmas are extracted from mushy reservoirs in both the lower and upper crust. The thermodynamic software MELTS is used to test a polybaric differentiation model whereby phonolites (sensu lato) are generated by extraction of residual liquids from an intermediate-crystallinity phonotephritic mush in the upper crust, which is in turn generated from the residual liquids of an intermediate-crystallinity basanitic mush at deeper levels. Latent heat spikes following crystallization of successive phases in the upper crustal reservoir provide a thermal buffering mechanism to slow down cooling and crystallization, permitting enhanced melt extraction at a particular crystallinity interval (mostly ∼40-60 vol. % crystals). MELTS modeling typically fits the observed chemical data adequately, although some major elements (mostly Al2O3) also indicate partial ‘cannibalization' of feldspar along with some magma mixing (and potentially minor crustal contamination
Time-ordering and a generalized Magnus expansion
Both the classical time-ordering and the Magnus expansion are well-known in
the context of linear initial value problems. Motivated by the noncommutativity
between time-ordering and time derivation, and related problems raised recently
in statistical physics, we introduce a generalization of the Magnus expansion.
Whereas the classical expansion computes the logarithm of the evolution
operator of a linear differential equation, our generalization addresses the
same problem, including however directly a non-trivial initial condition. As a
by-product we recover a variant of the time ordering operation, known as
T*-ordering. Eventually, placing our results in the general context of
Rota-Baxter algebras permits us to present them in a more natural algebraic
setting. It encompasses, for example, the case where one considers linear
difference equations instead of linear differential equations
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