2,359 research outputs found
In search of phylogenetic congruence between molecular and morphological data in bryozoans with extreme adult skeletal heteromorphy
peerreview_statement: The publishing and review policy for this title is described in its Aims & Scope. aims_and_scope_url: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=tsab20© Crown Copyright 2015. This document is the author's final accepted/submitted version of the journal article. You are advised to consult the publisher's version if you wish to cite from it
Spin Star as Switch for Quantum Networks
Quantum state transfer is an important task in quantum information
processing. It is known that one can engineer the couplings of a
one-dimensional spin chain to achieve the goal of perfect state transfer. To
leverage the value of these spin chains, a spin star is potentially useful for
connecting different parts of a quantum network. In this work, we extend the
spin-chain engineering problem to the problems with a topology of a star
network. We show that a permanently coupled spin star can function as a network
switch for transferring quantum states selectively from one node to another by
varying the local potentials only. Together with one-dimensional chains, this
result allows applications of quantum state transfer be applied to more general
quantum networks.Comment: 10 pages, 2 figur
Tectonic motion site survey of the National Radio Astronomy Observatory, Green Bank, West Virginia
A geological and geophysical site survey was made of the area around the National Radio Astronomy Observatory (NRAO) to determine whether there are at present local tectonic movements that could introduce significant errors to Very Long Baseline Interferometry (VLBI) geodetic measurements. The site survey consisted of a literature search, photogeologic mapping with Landsat and Skylab photographs, a field reconnaissance, and installation of a seismometer at the NRAO. It is concluded that local tectonic movement will not contribute significantly to VLBI errors. It is recommended that similar site surveys be made of all locations used for VLBI or laser ranging
Photochemistry of Furyl- and Thienyldiazomethanes: Spectroscopic Characterization of Triplet 3-Thienylcarbene
Photolysis (λ \u3e 543 nm) of 3-thienyldiazomethane (1), matrix isolated in Ar or N2 at 10 K, yields triplet 3-thienylcarbene (13) and α-thial-methylenecyclopropene (9). Carbene 13 was characterized by IR, UV/vis, and EPR spectroscopy. The conformational isomers of 3-thienylcarbene (s-E and s-Z) exhibit an unusually large difference in zero-field splitting parameters in the triplet EPR spectrum (|D/hc| = 0.508 cm–1, |E/hc| = 0.0554 cm–1; |D/hc| = 0.579 cm–1, |E/hc| = 0.0315 cm–1). Natural Bond Orbital (NBO) calculations reveal substantially differing spin densities in the 3-thienyl ring at the positions adjacent to the carbene center, which is one factor contributing to the large difference in D values. NBO calculations also reveal a stabilizing interaction between the sp orbital of the carbene carbon in the s-Z rotamer of 13 and the antibonding σ orbital between sulfur and the neighboring carbon—an interaction that is not observed in the s-E rotamer of 13. In contrast to the EPR spectra, the electronic absorption spectra of the rotamers of triplet 3-thienylcarbene (13) are indistinguishable under our experimental conditions. The carbene exhibits a weak electronic absorption in the visible spectrum (λmax = 467 nm) that is characteristic of triplet arylcarbenes. Although studies of 2-thienyldiazomethane (2), 3-furyldiazomethane (3), or 2-furyldiazomethane (4) provided further insight into the photochemical interconversions among C5H4S or C5H4O isomers, these studies did not lead to the spectroscopic detection of the corresponding triplet carbenes (2-thienylcarbene (11), 3-furylcarbene (23), or 2-furylcarbene (22), respectively)
Non-Markovian dynamics in a spin star system: The failure of thermalization
In most cases, a small system weakly interacting with a thermal bath will
finally reach the thermal state with the temperature of the bath. We show that
this intuitive picture is not always true by a spin star model where non-Markov
effect predominates in the whole dynamical process. The spin star system
consists a central spin homogeneously interacting with an ensemble of identical
noninteracting spins. We find that the correlation time of the bath is
infinite, which implies that the bath has a perfect memory, and that the
dynamical evolution of the central spin must be non- Markovian. A direct
consequence is that the final state of the central spin is not the thermal
state equilibrium with the bath, but a steady state which depends on its
initial state.Comment: 8 page
Transgressing the moral economy: Wheelerism and management of the nationalised coal industry in Scotland
This article illuminates the links between managerial style and political economy in post-1945 Britain, and explores the origins of the 1984–1985 miners' strike, by examining in longer historical context the abrasive attitudes and policies of Albert Wheeler, Scottish Area Director of the National Coal Board (NCB). Wheeler built on an earlier emphasis on production and economic criteria, and his micro-management reflected pre-existing centralising tendencies in the industries. But he was innovative in one crucial aspect, transgressing the moral economy of the Scottish coalfield, which emphasised the value of economic security and changes by joint industrial agreement
The most creative organization in the world? The BBC, 'creativity' and managerial style
The managerial styles of two BBC directors-general, John Birt and Greg Dyke, have often been contrasted but not so far analysed from the perspective of their different views of 'creative management'. This article first addresses the orthodox reading of 'Birtism'; second, it locates Dyke's 'creative' turn in the wider context of fashionable neo-management theory and UK government creative industries policy; third, it details Dyke's drive to change the BBC's culture; and finally, it concludes with some reflections on the uncertainties inherent in managing a creative organisation
Affordances, constraints and information flows as ‘leverage points’ in design for sustainable behaviour
Copyright @ 2012 Social Science Electronic PublishingTwo of Donella Meadows' 'leverage points' for intervening in systems (1999) seem particularly pertinent to design for sustainable behaviour, in the sense that designers may have the scope to implement them in (re-)designing everyday products and services. The 'rules of the system' -- interpreted here to refer to affordances and constraints -- and the structure of information flows both offer a range of opportunities for design interventions to in fluence behaviour change, and in this paper, some of the implications and possibilities are discussed with reference to parallel concepts from within design, HCI and relevant areas of psychology
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