1,380 research outputs found
Electronic Transport Properties of Pentacene Single Crystals upon Exposure to Air
We report the effect of air exposure on the electronic properties of
pentacene single crystals. Air can diffuse reversibly in and out of the
crystals and controls the physical properties. We discern two competing
mechanisms that modulate the electronic transport. The presence of oxygen
increases the hole conduction, as in dark four O2 molecules introduce one
charge carrier. This effect is enhanced by the presence of visible light.
Contrarily, water, present in ambient air, is incorporated in the crystal
lattice and forms trapping sites for injected charges.Comment: 16 pages, 3 figure
Between Censure and Liberalization: The Press and Publishing in Second Empire France
Napoleon III\u27s ambition to construct a paradoxical liberal empire encountered a major obstacle in the realm of the press, which chafed under censure and forced the Emperor to consider the ramifications that absolutism would have for his reign, given France\u27s revolutionary history. The article traces the history of censure under the Second Empire, to identify Napoleon III\u27s motivations for liberalization and its consequences for his regime
Positive surgical margins in nephron-sparing surgery; the great unknown
There is a currently a general trend towards organ-preserving surgery, and urology is no exception. Specifically, nephron-sparing surgery (NSS) has gained general acceptance for T1a renal cell carcinoma (guidelines recommendations). Moreover T1b, T2 and even T3 stage tumors have been included on the nephron sparing list at some centers. An unresolved issue is that of positive surgical margins (PSM), not only their detection but also the implications for follow up and treatment. This paper highlights data available on risk factors for PSM, their clinical relevance, and possible therapeutic consequences.
From the surgeon’s viewpoint, NSS is a daring and risky surgical procedure. Urological guidelines stress the importance of NSS, and thus the trend is moving in that direction. Unresolved, however, is the problem of PSM. Trifecta, MIC, and pentafecta are applicable concepts which attempt to define the optimal endpoint of NSS, but further elaboration is necessary. Specifically, research needs to focus less on the concept of definitive margins and more on their identification and avoidance. Although some studies suggest that PSMs do not influence overall survival rate, the basic idea of preserving tissue that is not cancerous leads to further medical, social, and psychological considerations
What Determines the Success of a Geographical Indication? A Price-based Meta-Analysis for GIs In Food Products
Food Consumption/Nutrition/Food Safety,
Quasi-coherent thermal emitter based on refractory plasmonic materials
The thermal emission of refractory plasmonic metamaterial - a titanium
nitride 1D grating - is studied at high operating temperature (540 {\deg}C). By
choosing a refractory material, we fabricate thermal gratings with high
brightness that are emitting mid-infrared radiation centered around 3 m.
We demonstrate experimentally that the thermal excitation of plasmon-polariton
on the surface of the grating produces a well-collimated beam with a spatial
coherence length of 32{\lambda} (angular divergence of 1.8{\deg}) which is
quasi-monochromatic with a full width at half maximum of 70 nm. These
experimental results show good agreement with a numerical model based on a
two-dimensional full-wave analysis in frequency domain.Comment: 10 pages, 5 figure
First-Class Approaches to Massive 2-Forms
Massive 2-forms are analyzed from the point of view of the Hamiltonian
quantization using the gauge-unfixing approach and respectively the
Batalin--Fradkin method. Both methods finally output the manifestly Lorentz
covariant path integral for 1- and 2-forms with Stueckelberg coupling.Comment: 14 page
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