Superconducting and Quantum-Effect Devices

Contains reports on nine research projects and a list of publications.National Science Foundation Fellowship MIP 88-58764Advanced Research Projects Agency/Consortium for Superconducting Electronics Contract MDA972-90-C-0021National Science Foundation Grant DMR 91-08748National Science Foundation Fellowship ProgramU.S. Air Force - Office of Scientific Research Grant F49620-92-J-0064National Science Foundation Grant DMR 94-0202

Optics and Quantum Electronics

Contains reports on eleven research projects.National Science Foundation (Grant EET 87-00474)Joint Services Electronics Program (Contract DAALO03-86-K-O002)Charles Stark Draper Laboratory, Inc. (Grant DL-H-2854018)National Science Foundation (Grant DMR 84-18718)National Science Foundation (Grant EET 87-03404)National Science Foundation (ECS 85-52701)US Air Force - Office of Scientific Research (Contract AFOSR-85-0213)National Institutes of Health (Contract 5-RO1-GM35459)US Navy - Office of Naval Research (Contract N00014-86-K-0117

Tuning skyrmions in B20 compounds by 4d and 5d doping

Skyrmion stabilization in novel magnetic systems with the B20 crystal structure is reported here, primarily based on theoretical results. The focus is on the effect of alloying on the 3d sublattice of the B20 structure by substitution of heavier 4d and 5d elements, with the ambition to tune the spin-orbit coupling and its influence on magnetic interactions. State-of-the-art methods based on density functional theory are used to calculate both isotropic and anisotropic exchange interactions. Significant enhancement of the Dzyaloshinskii-Moriya interaction is reported for 5d-doped FeSi and CoSi, accompanied by a large modification of the spin stiffness and spiralization. Micromagnetic simulations coupled to atomistic spin-dynamics and ab initio magnetic interactions reveal a helical ground state and field-induced skyrmions for all these systems. Especially small skyrmions $\sim$50 nm are predicted for Co$_{0.75}$Os$_{0.25}$Si, compared to $\sim$148 nm for Fe$_{0.75}$Co$_{0.25}$Si. Convex-hull analysis suggests that all B20 compounds considered here are structurally stable at elevated temperatures and should be possible to synthesize. This prediction is confirmed experimentally by synthesis and structural analysis of the Ru-doped CoSi systems discussed here, both in powder and in single-crystal forms.Comment: 18 pages, 21 figures, 9 table

Increased Expression of Bcl11b Leads to Chemoresistance Accompanied by G1 Accumulation

BACKGROUND: The expression of BCL11B was reported in T-cells, neurons and keratinocytes. Aberrations of BCL11B locus leading to abnormal gene transcription were identified in human hematological disorders and corresponding animal models. Recently, the elevated levels of Bcl11b protein have been described in a subset of squameous cell carcinoma cases. Despite the rapidly accumulating knowledge concerning Bcl11b biology, the contribution of this protein to normal or transformed cell homeostasis remains open. METHODOLOGY/PRINCIPAL FINDINGS: Here, by employing an overexpression strategy we revealed formerly unidentified features of Bcl11b. Two different T-cell lines were forced to express BCL11B at levels similar to those observed in primary T-cell leukemias. This resulted in markedly increased resistance to radiomimetic drugs while no influence on death-receptor apoptotic pathway was observed. Apoptosis resistance triggered by BCL11B overexpression was accompanied by a cell cycle delay caused by accumulation of cells at G1. This cell cycle restriction was associated with upregulation of CDKN1C (p57) and CDKN2C (p18) cyclin dependent kinase inhibitors. Moreover, p27 and p130 proteins accumulated and the SKP2 gene encoding a protein of the ubiquitin-binding complex responsible for their degradation was repressed. Furthermore, the expression of the MYCN oncogene was silenced which resulted in significant depletion of the protein in cells expressing high BCL11B levels. Both cell cycle restriction and resistance to DNA-damage-induced apoptosis coincided and required the histone deacetylase binding N-terminal domain of Bcl11b. The sensitivity to genotoxic stress could be restored by the histone deacetylase inhibitor trichostatine A. CONCLUSIONS: The data presented here suggest a potential role of BCL11B in tumor survival and encourage developing Bcl11b-inhibitory approaches as a potential tool to specifically target chemoresistant tumor cells

Local Resistance in Early Medieval Chinese Historiography and the Problem of Religious Overinterpretation

Official Chinese historiography is a treasure trove of information on local resistance to the centralised empire in early medieval China (third to sixth century). Sinologists specialised in the study of Chinese religions commonly reconstruct the religious history of the era by interpreting some of these data. In the process, however, the primary purpose of the historiography of local resistance is often overlooked, and historical interpretation easily becomes ‘overinterpretation’—that is, ‘fabricating false intensity’ and ‘seeing intensity everywhere’, as French historian Paul Veyne proposed to define the term. Focusing on a cluster of historical anecdotes collected in the standard histories of the four centuries under consideration, this study discusses the supposedly ‘religious’ nature of some of the data they contain

Is (poly-) substance use associated with impaired inhibitory control? A mega-analysis controlling for confounders.

Many studies have reported that heavy substance use is associated with impaired response inhibition. Studies typically focused on associations with a single substance, while polysubstance use is common. Further, most studies compared heavy users with light/non-users, though substance use occurs along a continuum. The current mega-analysis accounted for these issues by aggregating individual data from 43 studies (3610 adult participants) that used the Go/No-Go (GNG) or Stop-signal task (SST) to assess inhibition among mostly "recreational" substance users (i.e., the rate of substance use disorders was low). Main and interaction effects of substance use, demographics, and task-characteristics were entered in a linear mixed model. Contrary to many studies and reviews in the field, we found that only lifetime cannabis use was associated with impaired response inhibition in the SST. An interaction effect was also observed: the relationship between tobacco use and response inhibition (in the SST) differed between cannabis users and non-users, with a negative association between tobacco use and inhibition in the cannabis non-users. In addition, participants' age, education level, and some task characteristics influenced inhibition outcomes. Overall, we found limited support for impaired inhibition among substance users when controlling for demographics and task-characteristics

Kan växtskyddsåtgärder minska kväveförlusterna vid odling av höstvete?

During a three-year period (2002-2004), studies were carried out on nitrogen dynamics and losses during cultivation of winter wheat as influenced by disease and insect attacks. Three treatments with different degrees of plant protection (fungicides and pesticides??) were tested in a field trial on a silty clay soil in south-western Sweden. The wheat crop was continually inspected for pests and diseases. Direct measurements of nitrogen leaching were performed in tile-drained field plots equipped with individual collectors for drainage water. Ammonia emissions from the wheat stands were measured in one replicate plot during the first two growing seasons. Nitrogen accumulation and distribution in plants were investigated by sampling the crop at different stages of development and analysing different plant parts for total nitrogen content. Soil mineral nitrogen was determined within the 0-90 cm soil layer in early spring, at yellow ripeness and in November. Grain yield and grain nitrogen efficiency were always significantly larger and mean residual soil mineral nitrogen levels (at maturity and in November) significantly lower in the treatments with crop protection. At maturity, total N concentration in the straw was significantly higher in the treatment without plant protection. Mean nitrogen leaching was greater in the treatment without crop protection but the differences were not statistically significant. Ammonia emissions tended to be somewhat smaller in fungicide-treated wheat stands, but were very small in all treatments. The better N use efficiency with crop protection was probably due to a combination of larger N amounts in above-ground plant parts and better N translocation to grain when diseases were reduced

Towards a Pattern Language Approach to Document Description

Pattern libraries, originating in architecture, are a common way to share design solutions in interaction design and software engineering. Our aim in this paper is to consider patterns as a way of describing commonly-occurring document design solutions to particular problems, from two points of view. First, we are interested in their use as exemplars for designers to follow, and second, we suggest them as a means of understanding linguistic and graphical data for their organization into corpora that will facilitate descriptive work. We discuss the use of patterns across a range of disciplines before suggesting the need to place patterns in the context of genres, with each potentially belonging to a “home genre” in which it originates and to which it makes an implicit intertextual reference intended to produce a particular reader response in the form of a reading strategy or interpretative stance. We consider some conceptual and technical issues involved in the descriptive study of patterns in naturally-occurring documents, including the challenges involved in building a document corpus