102,597 research outputs found
The smallest strictly Neumaier graph and its generalisations
No full textA regular clique in a regular graph is a clique such that every vertex outside of the clique is adjacent to the same positive number of vertices inside the clique. We continue the study of regular cliques in edge-regular graphs initiated by A. Neumaier in the 1980s and attracting current interest. We thus define a Neumaier graph to be an non-complete edge-regular graph containing a regular clique, and a strictly Neumaier graph to be a non-strongly regular Neumaier graph. We first prove some general results on Neumaier graphs and their feasible parameter tuples. We then apply these results to determine the smallest strictly Neumaier graph, which has 16 vertices. Next we find the parameter tuples for all strictly Neumaier graphs having at most 24 vertices. Finally, we give two sequences of graphs, each with ith element a strictly Neumaier graph containing a 2i-regular clique (where i is a positive integer) and having parameters of an affine polar graph as an edge-regular graph. This answers questions recently posed by G. Greaves and J. Koolen
Bilayer Graphene Transistors for Analog Electronics
No full texthttp://www.gianlucafiori.org/articles/bilayer_electronics.pd
Velocity saturation in few-layer MoS2 transistor
No full texthttp://www.gianlucafiori.org/articles/fiori_MoS2.pd
Phase space reduction of star products on cotangent bundles
No full textIn this paper we construct star products on Marsden-Weinstein reduced
spaces in case both the original phase space and the reduced phase space are (symplectomorphic
to) cotangent bundles. Under the assumption that the original cotangent
bundle T∗Q carries a symplectic structure of form ωB0 = ω0 +π∗B0 with B0
a closed two-form on Q, is equipped by the cotangent lift of a proper and free Lie
group action on Q and by an invariant star product that admits a G-equivariant
quantum momentum map, we show that the reduced phase space inherits from
T∗Q a star product. Moreover, we provide a concrete description of the resulting
star product in terms of the initial star product on T∗Q and prove that our
reduction scheme is independent of the characteristic class of the initial star product.
Unlike other existing reduction schemes we are thus able to reduce not only
strongly invariant star products. Furthermore in this article, we establish a relation
between the characteristic class of the original star product and the characteristic
class of the reduced star product and provide a classification up to G-equivalence
of those star products on (T∗Q, ωB0 ), which are invariant with respect to a lifted
Lie group action. Finally, we investigate the question under which circumstances
‘quantization commutes with reduction’ and show that in our examples non-trivial
restrictions arise
Considerazioni sulle lacerazioni sottocutanee del tendine del quadricipite.
No full textThe Authors report a series of 7 patients operated for subcutaneous lesions of the quadriceps tendon using clinical, echotographic and isokinetic management
Color Doppler appearance of penile cavernosal-spongiosal communications in patientswith normal and impaired erection
No full textOur objective was to investigate prevalence and Doppler characteristics of penile cavernosal-spongiosal communications (CSC). These vessels are either anastomoses connecting the cavernosal arteries with the urethral arterial network or afferent vessels to the corpus spongiosum. Sixty-one consecutive patients underwent penile color Doppler US. Waveform changes in CSC were evaluated in comparison with changes in the cavernosal artery. Eighteen of 61 patients had normal erection, 17 of 61 had arterial insufficiency, and 26 of 61 had veno-occlusive dysfunction. Resistance index (RI) in CSC was significantly lower than in cavernosal arteries in all patients and increased during phases 1-2 (positive diastolic flow). Peak systolic velocity (PSV) in CSC was significantly higher in the patients with veno-occlusive dysfunction. During cavernosal phase 4 (diastolic flow reversal) CSC of patients with normal erection or with arterial insufficiency disappeared, underwent markedly reduced diastolic flow, or had systolic flow inversion. Conversely, low resistance flow was appreciable in CSC of patients with veno-occlusive dysfunction who reached phase 4. During phase 5 (systolic peak reduction) all CSC disappeared. Color Doppler US allows evaluation of CSC both in patients with normal and impaired erection
Bibliographie Hilarion G. Petzold 1958 – 2009 mit Anhang als Einführung
No full textDieses Archiv enthält die Gesamtbibliographie der Werke des Autors nebst einiger Texte „Über H. G. Petzold“ im Schlussteil der Bibliographie sowie einen Anhang mit einer Einführung in die Architektur des Werkes in seinem wissenslogischen Aufbau als Ausarbeitung seines „Tree of Science Modells“ (2007).This archive contains the complete bibliography of the author and some texts about H. G. Petzold, moreover an epilogue with an introduction to the architecture of the works in its epistemological structure and composition and as an elaborations of Petzold’s „Tree of Science Modell (2007).https://www.fpi-publikation.de/polyloge/01-2009-petzold-h-g-gesamtbibliographie-h-g-petzold-1958-2009-updating-november2009/peerReviewedpublishedVersio
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Flicker noise in graphene-based Hall sensors
No full textWe present an investigation of shot noise in graphene-based Hall sensors, with the purpose of evaluating their detection limit and of developing strategies to improve their characteristics. We perform measurements on two devices, one with a defective contact that could however be used as a gate to control the carrier density in the device and the other with all contacts working. We discuss the results in terms of the dependence of the noise power spectral density on the carrier density and on the DC bias current. Finally, we provide an estimate of the detection limit, pointing out that the approach commonly used in the literature for its evaluation is flawed
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