4,190 research outputs found
Local authorities should be at the forefront of going green. This will see economic returns as well as environmental benefits
Paul O’Brien argues that councils should be leading the way with renewable energy schemes. They can reap important economic and social rewards as well as environmental benefits
Synthesis of CdS and CdSe nanoparticles by thermolysis of diethyldithio- or diethyldiseleno-carbamates of cadmium
Cadmium sulfide and cadmium selenide nanoparticles have been synthesised by a novel route involving the thermal
decomposition of the bisdiethyldithio- or bisdiethyldiseleno-carbamates of cadmium in refluxing 4-ethylpyridine solutions.
The nanodispersed materials were studied by electronic spectroscopy and bandgaps were blue shifted. Transmission electron
microscopy of the samples showed material to be in the nanosize range and crystalline
Lattice supersymmetry and order-disorder coexistence in the tricritical Ising model
We introduce and analyze a quantum spin/Majorana chain with a tricritical
Ising point separating a critical phase from a gapped phase with order-disorder
coexistence. We show that supersymmetry is not only an emergent property of the
scaling limit, but manifests itself on the lattice. Namely, we find explicit
lattice expressions for the supersymmetry generators and currents. Writing the
Hamiltonian in terms of these generators allows us to find the ground states
exactly at a frustration-free coupling. These confirm the coexistence between
two (topologically) ordered ground states and a disordered one in the gapped
phase. Deforming the model by including explicit chiral symmetry breaking, we
find the phases persist up to an unusual chiral phase transition where the
supersymmetry becomes exact even on the lattice.Comment: 5+3 pages. v2: added three short appendices, including numerics
comparing various four-fermi perturbation
Drivers of Choice: Parents, Transportation, and School Choice
Based on surveys of two districts, explores the extent to which distance, transportation time, and mode prevent low- and moderate-income families from choosing private, charter, or non-neighborhood schools. Calls for decentralized transportation policies
Surface Free Energies, Interfacial Tensions and Correlation Lengths of the ABF Models
The surface free energies, interfacial tensions and correlation lengths of
the Andrews-Baxter-Forrester models in regimes III and IV are calculated with
fixed boundary conditions. The interfacial tensions are calculated between
arbitrary phases and are shown to be additive. The associated critical
exponents are given by with in regime III
and with in regime IV. Our results are
obtained using general commuting transfer matrix and inversion relation methods
that may be applied to other solvable lattice models.Comment: 21 pages, LaTeX 2e, requires the amsmath packag
Developing a coordination chemistry of intact quantum dots: the preparation of novel nanocomposites of PbS with CdS or CdSe
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Deposit insurance, bank incentives, and the design of regulatory policy
This paper was presented at the conference "Financial services at the crossroads: capital regulation in the twenty-first century" as part of session 6, "The role of capital regulation in bank supervision." The conference, held at the Federal Reserve Bank of New York on February 26-27, 1998, was designed to encourage a consensus between the public and private sectors on an agenda for capital regulation in the new century.Deposit insurance ; Bank investments ; Bank supervision ; Bank capital
The Efficiency and the Conduct of European Banks: Developments after 1992
European Central Bank; economic integration; economic performance; EMU; Euro; financial markets
Introduction: Peasants, Pastoralists and Proletarians: Joining the Debates on Trajectories of Agrarian Change, Livelihoods and Land Use
Recent changes in the agrarian studies and geography literatures present differing views on the pace and trajectory of change in rural developing areas. In this special section of Human Geography, we contrast the theoretical and practice implications of these differing approaches, namely depeasantization, accumulation by dispossession and deproletarianization. Depeasantization refers to change in livelihood activities out of agriculture, long theorized as necessary for an area’s transition into capitalism. Accumulation by dispossession is a process of on-going capital accumulation where a give resource is privatized, seized, or in some other manner alienated from common ownership in order to provide a basis for continued capital accumulation. Deproletarianization occurs when workers are no longer able to freely commodify and recommodify their only commodity, their own labour. In this section, we explore these three theses with case studies that draw upon empirical data. The papers in this collection all speak to one aspect or another of these debates. We do not intend to try to determine a “best approach”, rather we explore strengths and weaknesses of each argument.
The production of nature, change in the mode of production and the political economy of nature are discussed in the first article by Brent McCusker. Phil O’Keefe and Geoff O’Brien examine the evolution of worked landscape under pre-capitalist modes of production in riverine ecologies. Through further case studies, Paul O’Keefe explores links between livelihoods and climate change in Mt. Kilimanjaro, Tanzania, while Franklin Graham explores the persistence of pastoralism in the Sahel. Finally, Naomi Shanguhyia and Brent McCusker examine the process of governance in dry land Kenya through the study of chronic food shortages
Can magnetar spin-down power extended emission in some short GRBs?
Extended emission gamma-ray bursts are a subset of the `short' class of burst
which exhibit an early time rebrightening of gamma emission in their light
curves. This extended emission arises just after the initial emission spike,
and can persist for up to hundreds of seconds after trigger. When their light
curves are overlaid, our sample of 14 extended emission bursts show a
remarkable uniformity in their evolution, strongly suggesting a common central
engine powering the emission. One potential central engine capable of this is a
highly magnetized, rapidly rotating neutron star, known as a magnetar.
Magnetars can be formed by two compact objects coallescing, a scenario which is
one of the leading progenitor models for short bursts in general. Assuming a
magnetar is formed, we gain a value for the magnetic field and late time spin
period for 9 of the extended emission bursts by fitting the magnetic dipole
spin-down model of Zhang & Meszaros (2001). Assuming the magnetic field is
constant, and the observed energy release during extended emission is entirely
due to the spin-down of this magnetar, we then derive the spin period at birth
for the sample. We find all birth spin periods are in good agreement with those
predicted for a newly born magnetar.Comment: 7 pages, 4 figures, 3 tables. Accepted for publication in MNRA
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