Nearly Antiferromagnetic Fermi Liquids: A Progress Report

I describe recent theoretical and experimental progress in understanding the physical properties of the two dimensional nearly antiferromagnetic Fermi liquids (NAFL's) found in the normal state of the cuprate superconductors. In such NAFL's, the magnetic interaction between planar quasiparticles is strong and peaked at or near the commensurate wave vector, $Q \equiv (\pi,\pi)$. For the optimally doped and underdoped systems, the resulting strong antiferromagnetic correlations produce three distinct magnetic phases in the normal state: mean field above $T_{cr}$, pseudoscaling between $T_{cr}$ and $T_*$, and pseudogap below $T_*$. I present arguments which suggest that the physical origin of the pseudogap found in the quasiparticle spectrum below $T_{cr}$ is the formation of a precursor to a spin-density-wave-state, describe the calculations based on this scenario of the dynamical spin susceptibility, Fermi surface evolution, transport, and Hall effect, and summarize the experimental evidence in its support.Comment: LATEX + PS figures. To appear in the proceedings of the Euroconference on "Correlations in Unconventional Quantum Liquids," Evora, Portugal, October 199

Editorial for Special Edition, Digital Representations: Re-Using and Publishing Digital Qualitative Data

This collection of papers comprises five contributions with a social science or social historical perspective that present the current state of the art in the field of re-using and publishing digital qualitative data. The articles address the use of digital sources in qualitative research in both research and teaching, charting types of use over the past 10 years, and looking forward to emerging practices and methods, such as the promise and potential that technological innovations can bring to enable new ways of presenting and publishing qualitative research. Some of the papers make use of direct linking allowing the reader to explore ?live? data sources, offering an opportunity to see how research transparency might be operationalized in the presentation of qualitative findings and reporting. The papers reference major contributions to the literature and present stimulating debates on the topic and build on previously well-cited publications in which the editors have presented state-of- the-art articles on secondary analysis of qualitative data

Revisiting Qualitative Data Reuse

Secondary analysis of qualitative data entails reusing data created from previous research projects for new purposes. Reuse provides an opportunity to study the raw materials of past research projects to gain methodological and substantive insights. In the past decade, use of the approach has grown rapidly in the United Kingdom to become sufficiently accepted that it must now be regarded as mainstream. Several factors explain this growth: the open data movement, research funders’ and publishers’ policies supporting data sharing, and researchers seeing benefits from sharing resources, including data. Another factor enabling qualitative data reuse has been improved services and infrastructure that facilitate access to thousands of data collections. The UK Data Service is an example of a well-established facility; more recent has been the proliferation of repositories being established within universities. This article will provide evidence of the growth of data reuse in the United Kingdom and in Finland by presenting both data and case studies of reuse that illustrate the breadth and diversity of this maturing research method. We use two distinct data sources that quantify the scale, types, and trends of reuse of qualitative data: (a) downloads of archived data collections held at data repositories and (b) publication citations. Although the focus of this article is on the United Kingdom, some discussion of the international environment is provided, together with data and examples of reuse at the Finnish Social Science Data Archive. The conclusion summarizes the major findings, including some conjectures regarding what makes qualitative data attractive for reuse and sharing. </jats:p

Particles in non-Abelian gauge potentials - Landau problem and insertion of non-Abelian flux

We study charged spin-1/2 particles in two dimensions, subject to a perpendicular non-Abelian magnetic field. Specializing to a choice of vector potential that is spatially constant but non-Abelian, we investigate the Landau level spectrum in planar and spherical geometry, paying particular attention to the role of the total angular momentum J = L +S. After this we show that the adiabatic insertion of non-Abelian flux in a spin-polarized quantum Hall state leads to the formation of charged spin-textures, which in the simplest cases can be identified with quantum Hall Skyrmions.Comment: 24 pages, 10 figures (with corrected legends

Opportunities From the Digital Revolution: Implications for Researching, Publishing, and Consuming Qualitative Research

In the 1990s, the term 'online' research emerged as a new and vibrant suite of methods, focused on exploitation of sources not collected by traditional social science methods. Today, at least one part of the research life cycle is likely to be carried out 'online,' from data collection through to publishing. In this article, we seek to understand emergent modes of doing and reporting qualitative research 'online.' With a greater freedom now to term oneself a 'researcher,' what opportunities and problems do working with online data sources bring? We explore implications of emerging requirements to submit supporting data for social science journal articles and question whether these demands might disrupt the very nature of and identity of qualitative research. Finally, we examine more recent forms of publishing and communicating research that support outputs where data play an integral role in elucidating context and enhancing the reading experience

Fear expression is suppressed by tyrosine administration

Animal studies have demonstrated that catecholamines regulate several aspects of fear conditioning. In humans, however, pharmacological manipulations of the catecholaminergic system have been scarce, and their primary focus has been to interfering with catecholaminergic activity after fear acquisition or expression had taken place, using L-Dopa, primarily, as catecholaminergic precursor. Here, we sought to determine if putative increases in presynaptic dopamine and norepinephrine by tyrosine administered before conditioning could affect fear expression. Electrodermal activity (EDA) of 46 healthy participants (24 placebo, 22 tyrosine) was measured in a fear instructed task. Results showed that tyrosine abolished fear expression compared to placebo. Importantly, tyrosine did not affect EDA responses to the aversive stimulus (UCS) or alter participants' mood. Therefore, the effect of tyrosine on fear expression cannot be attributed to these factors. Taken together, these findings provide evidence that the catecholaminergic system influences fear expression in humans

INVESTIGATION ON THE CERVICAL SPINE MOTION

Several investigations on the problem of cervical spine motion describe the difficulties of measuring the movement exactly. Those models had to deal with the difficulties in fixation of the human head and to track the range of motion in degrees with respect to the three directions of movement; flexionlextension, lateral bending and rotation. The only objective method of measuring cervical spine movement and COlC1 or C11C2 displacements is the functional computer tomogram as described by Dvorak et al. The aim of our survey has been to identify differences between the "normaln and pathologic cervical spine (after whip leash injuries, disc diseases or spondylarthrosis in sport) as it relates to the range of movement and angular velocity. Two groups of 15 probants have been tested by a new computer-controlled setup. By using a three-dimensional motion-analysis-system special rigid-body software has been developed to calculate the cervical spine motion in all three coordinate directions. This represents the first time that it has been possible to obtain results about the movement and their time-derivations. These angles and the angular velocities were traced for 15 normal individuals and for 15 persons suffering with cervical spine problems. The setup for testing patients was no more than a small frame like sunglasses which gave exact information about the movement in space. This information gave accurate data which permitted calculation of the amount of motion concerning the patient's personal orientation in space and was additionally used to compute the coupled motions to the probants reference coordinate system. The present investigation demonstrated significant differences in the range of motion between normal individuals and patients with cervical spine problems in all defined direction. Our first conclusion so far is, that there are possibilities to measure those differences in cervical spine motion by the presented biomechanical measurement setup very easily. Furthermore, the setup is capable of providing accurate results about the range of motion, coupled motion and their time-derivations rapidly without the use of x-ray technology and x-ray exposition for the patient. These possibility and the good results are very important to judge problems after "ship leash injuries" and other cervical spine diseases in sport. The positive results raise the possibility that the technique may be employed to judge problems and other cervical spine injuries associated with sport. We conclude that the biomechanical measurement-setup presented here provides an easy method to measure differences in cervical spine motion

A theory of topological edges and domain walls

We investigate domain walls between topologically ordered phases in two spatial dimensions and present a simple but general framework from which their degrees of freedom can be understood. The approach we present exploits the results on topological symmetry breaking that we have introduced and presented elsewhere. After summarizing the method, we work out predictions for the spectrum of edge excitations and for the transport through edges in some representative examples. These include domain walls between the Abelian and non-Abelian topological phases of Kitaev's honeycomb lattice model in a magnetic field, as well as recently proposed domain walls between spin polarized and unpolarized non-Abelian fractional quantum Hall states at different filling fractions.Comment: 4 pages, 1 figure, late