12,744 research outputs found
Edge Electron Gas
The uniform electron gas, the traditional starting point for density-based
many-body theories of inhomogeneous systems, is inappropriate near electronic
edges. In its place we put forward the appropriate concept of the edge electron
gas.Comment: 4 pages RevTex with 7 ps-figures included. Minor changes in
title,text and figure
Successful Treatment of Pneumothorax in a Dog With Sterile Pleural Fibrosis Caused by Chylothorax
A 2-year-old, 12 kg, intact male crossbreed dog was presented with respiratory distress, exercise intolerance, and gagging. Plain thoracic radiographs revealed severe pleural effusion. Although bilateral needle thoracocentesis and chest tube placement were performed, no re-expansion of the lung lobes occurred. Pleural effusion was of chylous quality and led to lung entrapment. Computer tomography revealed a highly atrophic and atelectatic right middle lung lobe. The remaining lung lobes were only expanded to ~40%. Visceral pleura and pericardium showed a heterogeneous thickening consistent with pleural fibrosis. Partial pericardiectomy with resection of the middle lung lobe through a right lateral thoracotomy was performed. Ligation of the thoracic duct and ablation of the cisterna chyli was achieved through a single paracostal approach. Histopathology revealed chronic-active proliferative beginning granulomatous pleuritis, fibrotic pericarditis, and partial coagulative necrosis with incomplete granulomatous sequestration in the resected middle lung lobe. Chylothorax resolved after surgical intervention. Active pleural effusion resolved, and lung entrapment changed to trapped lung disease. The remaining lung lobes re-expanded to ~80% over the following 6 days. The dog was discharged 10 days later. Mild to moderate pleural effusion of non-chylic quality was present during the following 4 months. Meloxicam was administered for 4 months because of its anti-fibrotic and anti-inflammatory properties. Fifteen months later, thoracic radiographs revealed full radiologic expansion of the lungs with persistent mild pleural fibrosis. To the authors' knowledge, this is the first case report of pneumothorax due pleural fibrosis caused by chylothorax in a dog with an excellent clinical outcome
Lattice deformations at martensite-martensite interfaces in Ni-Al
The atomic configurations at macrotwin interfaces between microtwinned martensite plates in material are investigated using high resolution transmission electron microscopy (HRTEM). The observed structures are interpreted in view of possible formation mechanisms of these interfaces. A distinction is made between cases in which the microtwins, originating from mutually perpendicular \{110\} austenite planes, enclose a final angle larger or smaller than , measured over the boundary. Two different configurations, one with crossing microtwins and the other with ending microtwins producing a step configuration are described. The latter is related with the existence of microtwin sequences with changing variant widths. Although both features appear irrespective of the material’s preparation technique, rapid solidification seems to prefer the step configuration. Depending on the actual case, tapering, bending and tip splitting of the small microtwin variants is observed. Sever lattice deformations and reorientations occur in a region of 5 – 10 nm around the interface while sequences of single plane ledges gradually bending the microtwins are found up to 50 nm away form the interface. These structures and deformations are interpreted in view of the need to accommodate any remaining stresses
Precision laser range finder system design for Advanced Technology Laboratory applications
Preliminary system design of a pulsed precision ruby laser rangefinder system is presented which has a potential range resolution of 0.4 cm when atmospheric effects are negligible. The system being proposed for flight testing on the advanced technology laboratory (ATL) consists of a modelocked ruby laser transmitter, course and vernier rangefinder receivers, optical beacon retroreflector tracking system, and a network of ATL tracking retroreflectors. Performance calculations indicate that spacecraft to ground ranging accuracies of 1 to 2 cm are possible
Thermal analysis of submicron nanocrystalline diamond films
The thermal properties of sub-μm nanocrystalline diamond films in the range of 0.37–1.1 μm grown by hot filament CVD, initiated by bias enhanced nucleation on a nm-thin Si-nucleation layer on various substrates, have been characterized by scanning thermal microscopy. After coalescence, the films have been outgrown with a columnar grain structure. The results indicate that even in the sub-μm range, the average thermal conductivity of these NCD films approaches 400 W m− 1 K− 1. By patterning the films into membranes and step-like mesas, the lateral component and the vertical component of the thermal conductivity, k<sub>lateral</sub> and k<sub>vertical</sub>, have been isolated showing an anisotropy between vertical conduction along the columns, with k<sub>vertical</sub> ≈ 1000 W m− 1 K− 1, and a weaker lateral conduction across the columns, with k<sub>lateral</sub> ≈ 300 W m− 1 K− 1
Spin hydrodynamics in the S = 1/2 anisotropic Heisenberg chain
We study the finite-temperature dynamical spin susceptibility of the
one-dimensional (generalized) anisotropic Heisenberg model within the
hydrodynamic regime of small wave vectors and frequencies. Numerical results
are analyzed using the memory function formalism with the central quantity
being the spin-current decay rate gamma(q,omega). It is shown that in a generic
nonintegrable model the decay rate is finite in the hydrodynamic limit,
consistent with normal spin diffusion modes. On the other hand, in the gapless
integrable model within the XY regime of anisotropy Delta < 1 the behavior is
anomalous with vanishing gamma(q,omega=0) proportional to |q|, in agreement
with dissipationless uniform transport. Furthermore, in the integrable system
the finite-temperature q = 0 dynamical conductivity sigma(q=0,omega) reveals
besides the dissipationless component a regular part with vanishing
sigma_{reg}(q=0,omega to 0) to 0
Popular Conceptions of Nationhood in Old and New European Member States: Partial Support for the Ethnic-Civic Framework
One of the most influential theories in the study of nationalism has been the ethnic-East/civic-West framework developed by Hans Kohn. Using the 2002 Eurobarometer survey on national identity and building on earlier survey studies, this article examines whether the Kohn framework is valid at the level of popular understandings of nationhood. It scrutinizes the framework both conceptually - do people define nationhood in civic or ethnic terms? - and regionally - is the East indeed more ethnic than the West and the West more civic than the East? It will show that identity markers cluster in a political, a cultural and an ethnic dimension. Respondents do not see these dimensions as competing sources of nationhood, however. The article further lends some support for the regional component of the framework. Lastly, it argues that it is the intensity of national identifications rather than their qualitative nature (ethnic-civic) that correlates with xenophobia. © 2006 Taylor & Francis
Impulse oscillometry identifies peripheral airway dysfunction in children with adenosine deaminase deficiency.
Adenosine deaminase-deficient severe combined immunodeficiency (ADA-SCID) is characterized by impaired T-, B- and NK-cell function. Affected children, in addition to early onset of infections, manifest non-immunologic symptoms including pulmonary dysfunction likely attributable to elevated systemic adenosine levels. Lung disease assessment has primarily employed repetitive radiography and effort-dependent functional studies. Through impulse oscillometry (IOS), which is effort-independent, we prospectively obtained objective measures of lung dysfunction in 10 children with ADA-SCID. These results support the use of IOS in the identification and monitoring of lung function abnormalities in children with primary immunodeficiencies
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