7,543 research outputs found
Quantum Interference and Inelastic Scattering in a Model Which-Way Device
A which-way device is one which is designed to detect which of 2 paths is
taken by a quantum particle, whether Schr\"odinger's cat is dead or alive. One
possible such device is represented by an Aharonov-Bohm ring with a quantum dot
on one branch. A charged cantilever or spring is brought close to the dot as a
detector of the presence of an electron. The conventional view of such a device
is that any change in the state of the cantilever implies a change in the
electron state which will in turn destroy the interference effects. In this
paper we show that it is in fact possible to change the state of the oscillator
while preserving the quantum interference phenomenon.Comment: 5 pages, 7 figures, Localisation 2002 Toky
AEM of extraterrestrial materials
Modifications to and maintenance of the JEOL 100 CX electron microscope are discussed. Research activity involving extraterrestrial matter, cosmic dust, stratosphere dust, and meteorites is summarized
Devolution as process: institutional structures, state personnel and transport policy in the United Kingdom
Devolution has been described as a key ‘global trend’ over recent decades as governments have decentralised power and responsibilities to subordinate regional institutions (Rodriguez-Pose and Gill, 2003). UK devolution is characterised by its asymmetrical nature with different territories granted different institutional arrangements and powers. In this paper, we seek examine the role of state personnel in mobilising the new institutional machinery and managing the process of devolution, focusing on transport policy. Our research shows a clear contrast between London and Northern Ireland, on the one hand, and Scotland and Wales, on the other, in terms of the effectiveness of political leaders in creating clear policy priorities and momentum in transport
Comparative Analysis of Non-thermal Emissions and Study of Electron Transport in a Solar Flare
We study the non-thermal emissions in a solar flare occurring on 2003 May 29
by using RHESSI hard X-ray (HXR) and Nobeyama microwave observations. This
flare shows several typical behaviors of the HXR and microwave emissions: time
delay of microwave peaks relative to HXR peaks, loop-top microwave and
footpoint HXR sources, and a harder electron energy distribution inferred from
the microwave spectrum than from the HXR spectrum. In addition, we found that
the time profile of the spectral index of the higher-energy (\gsim 100 keV)
HXRs is similar to that of the microwaves, and is delayed from that of the
lower-energy (\lsim 100 keV) HXRs. We interpret these observations in terms
of an electron transport model called {\TPP}. We numerically solved the
spatially-homogeneous {\FP} equation to determine electron evolution in energy
and pitch-angle space. By comparing the behaviors of the HXR and microwave
emissions predicted by the model with the observations, we discuss the
pitch-angle distribution of the electrons injected into the flare site. We
found that the observed spectral variations can qualitatively be explained if
the injected electrons have a pitch-angle distribution concentrated
perpendicular to the magnetic field lines rather than isotropic distribution.Comment: 32 pages, 12 figures, accepted for publication in The Astronomical
Journa
Progress toward a cosmic dust collection facility on space station
Scientific and programmatic progress toward the development of a cosmic dust collection facility (CDCF) for the proposed space station is documented. Topics addressed include: trajectory sensor concepts; trajectory accuracy and orbital evolution; CDCF pointing direction; development of capture devices; analytical techniques; programmatic progress; flight opportunities; and facility development
Weiss oscillations in the electronic structure of modulated graphene
We present a theoretical study of the electronic structure of modulated
graphene in the presence of a perpendicular magnetic field. The density of
states and the bandwidth for the Dirac electrons in this system are determined.
The appearance of unusual Weiss oscillations in the bandwidth and density of
states is the main focus of this work.Comment: 8 pages, 2 figures, accepted in J. Phys.: Conden. mat
Predicting the outcome of Disability Living Allowance (DLA) adult claims
This working paper considers how well coded data from Disability Living Allowance (DLA) adult claim packs can predict the outcome of these claims. The probability of receiving a care or mobility award is estimated. A range of control variables are considered. First using items that reflect the entitlement criteria for care and mobility awards and then looking at whether additional evidence was required as part of the claim process. Predicted results from these estimates were then compared with real world decisions and those made by Decision Makers on the basis of the coded information from claim packs
Doing evolution in economic geography
Evolutionary approaches in economic geography face questions about the relationships between their concepts, theories, methods, politics, and policy implications. Amidst the growing but unsettled consensus that evolutionary approaches should employ plural methodologies, the aims here are, first, to identify some of the difficult issues confronting those working with different frameworks. The concerns comprise specifying and connecting research objects, subjects, and levels; handling agency and context; engaging and integrating the quantitative and the qualitative; comparing cases; and, considering politics, policy, and praxis. Second, the purpose is to articulate a distinctive geographical political economy approach, methods, and illustrative examples in addressing these issues. Bringing different views of evolution in economic geography into dialogue and disagreement renders methodological pluralism a means toward improved understanding and explanation rather than an end in itself. Confronting such thorny matters needs to be embedded in our research practices and supported by greater openness; more and better substantiation of our conceptual, theoretical, and empirical claims; enhanced critical reflection; and deeper engagement with politics, policy, and praxis
Give them time to think: more learning with less listening
There are many strategies for increasing student engagement. One method that is called think-pair-share , where students are invited to think about a problem (think), then discuss it with their neighbours (pair), and finally present their solution to the instructor and the rest of the class (share). We have adapted this strategy for use with large chemistry lectures (intro and organic), where the method is throughout the class lecture. Therefore, there is less listening to the course instructor and more time engaged in peer-learning. This presentation will describe this method for increasing engagement in large classes
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