2,353 research outputs found

    On explicit results at the intersection of the Z_2 and Z_4 orbifold subvarieties in K3 moduli space

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    We examine the recently found point of intersection between the Z_2 and Z_4 orbifold subvarieties in the K3 moduli space more closely. First we give an explicit identification of the coordinates of the respective Z_2 and Z_4 orbifold theories at this point. Secondly we construct the explicit identification of conformal field theories at this point and show the orthogonality of the two subvarieties.Comment: Latex, 23 page

    Laser Doppler velocimeter aerial spray measurements

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    An experimental research program for measuring the location, spatial extent, and relative concentration of airborne spray clouds generated by agricultural aircraft is described. The measurements were conducted with a ground-based laser Doppler velocimeter. The remote sensing instrumentation, experimental tests, and the results of the flight tests are discussed. The cross section of the aerial spray cloud and the observed location, extent, and relative concentration of the airborne particulates are presented. It is feasible to use a mobile laser Doppler velocimeter to track and monitor the transport and dispersion of aerial spray generated by an agricultural aircraft

    Ultrasound mapping of lymph node and subcutaneous metastases in patients with cutaneous melanoma: Results of a prospective multicenter study

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    Background: Ultrasound (sonography, B-mode sonography, ultrasonography) examination improves the sensitivity in more than 25% compared to the clinical palpation, especially after surgery on the regional lymph node area. Objective: To evaluate the distribution of metastases during follow-up in the draining lymph node areas from the scar of primary to regional lymph nodes ( head and neck, supraclavicular, axilla, infraclavicular, groin) in patients with cutaneous melanoma with or without sentinel lymph node biopsy (SLNB) or former elective or consecutive complete lymph node dissection in case of positive sentinel lymph node (CLND). Methods: Prospective multicenter study of the Departments of Dermatology of the Universities of Homburg/Saar, Tubingen and Munich (Germany) in which the distribution of lymph node and subcutaneous metastases were mapped from the scar of primary to the lymphatic drainage region in 53 melanoma patients ( 23 women, 30 men; median age: 64 years; median tumor thickness: 1.99 mm) with known primary, visible lymph nodes or subcutaneous metastases proven by ultrasound and histopathology during the follow-up. Results: Especially in the axilla, infraclavicular region and groin the metastases were not limited to the anatomic lymph node regions. In 5 patients (9.4%) ( 4 of them were in stage IV) lymph node metastases were not located in the corresponding lymph node area. 32 patients without former SLNB had a time range between melanoma excision and lymph node metastases of 31 months ( median), 21 patients with SLNB had 18 months ( p < 0.005). In 11 patients with positive SLNB the time range was 17 months, in 10 patients with negative SLNB 21 months ( p < 0.005); in 32 patients with CLND the time range was 31 m< 0.005). In thinner melanomas lymph node metastases occurred later ( p < 0.05). Conclusions: After surgery of cutaneous melanoma, SLNB and CLND the lymphatic drainage can show significant changes which should be considered in clinical and ultrasound follow-up examinations. Especially for high-risk melanoma patients follow-up examinations should be performed at intervals of 3 months in the first years. Patients at stage IV should be examined in all regional lymph node areas clinically and by ultrasound. Copyright (c) 2006 S. Karger AG, Basel

    A Dynamic Ion-Atom Hybrid Trap for High-Resolution Cold-Collision Studies

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    We present a dynamic ion-atom hybrid trap for studies of cold ion-neutral collisions and reactions with a significantly improved energy resolution compared with previous experiments. Our approach is based on pushing a cloud of laser-cooled Rb atoms through a stationary Coulomb crystal of cold ions by using precisely controlled, tunable radiation pressure forces. We demonstrate the tuning of the atom kinetic energies over an interval ranging from 30 mK up to 350 mK with energy spreads as low as 24 mK, inferred from the comparison of experimental time-of-flight measurements with Monte Carlo trajectory simulations. We also demonstrate the first applications of our method to the investigation of chemical reactions. Our development opens up perspectives for accurate studies of the energy dependence of the reaction rates, the dynamics, and the reaction-product ratios of the ion-neutral processes in the cold regime. It also paves the way for the realization of fully energy- and state-controlled cold-collision experiments

    Die Behandlungspraxis bei Patienten mit isolierter stumpfer Milzverletzung: Eine Befragung der Schweizer Traumatologen

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    Zusammenfassung: Hintergrund: Das nicht-operative Management (NOM) des stumpfen Milztraumas hat sich in den vergangenen Jahren als Therapiekonzept etabliert. Es bestehen jedoch zahlreiche Kontroversen bezüglich der Überwachung und Nachsorge dieser Patienten. Ziel dieser Studie war es, mittels einer Umfrage bei Mitgliedern der Schweizerischen Gesellschaft für Allgemeine und Unfallchirurgie (SGAUC) die aktuelle Praxis bezüglich NOM beim isolierten Milztrauma zu erfassen und mögliche Diskrepanzen zur aktuellen Literatur zu eruieren. Studiendesign und Untersuchungsmethode: Sämtliche praktizierende Mitglieder der SGAUC wurden mittels schriftlichem Umfragebogen adressiert. Dieser enthielt Fragen zu Person und Klinik des Chirurgen, Fragen zu Diagnostik und Management während der Hospitalisation sowie zu radiologischen Verlaufskontrollen und zur stufenweisen Wiederaufnahme von Alltagsaktivitäten. Ergebnisse: An der Umfrage nahmen 52 von 165 (31,5%) praktizierenden Mitgliedern der SGAUC teil. Diese deckten 62,8% aller Schweizer Traumazentren ab. Vierzehn Befragte (26,9%) verfügen an ihrer Klinik über ein Protokoll zur Behandlung des Milztraumas. Als initiale Bildgebung beim hämodynamisch stabilen Patienten mit stumpfem Abdomaninaltrauma gaben 82,7% der Befragten die Sonographie an. Bei sonographischem Verdacht auf Milztrauma verzichteten allerdings 19,2% der Befragten auf eine weitergehende Diagnostik. Die Hälfte der Chirurgen gab außerdem an, bei sichtbarem Kontrastmittelextravasat aus der Milz keine weiteren therapeutischen Maßnahmen einzuleiten. 86,5% der Befragten würden Patienten mit niedriggradigem Milztrauma für durchschnittlich 1,6 (0-4Tage) in einem kontinuierlich-monitorisierten Bett überwachen. Keine Unterschiede wurden hinsichtlich der Aktivitätsrestriktion zwischen mittel- und hochgradigen Milztraumata gemacht. Schlussfolgerung: Aufgrund eines Mangels an evidenzbasierten Richtlinien zum NOM des Milztraumas gibt es eine beträchtliche Variabilität in der klinischen Praxis selbst unter erfahrenen Chirurgen. Die größten Diskrepanzen zu den Empfehlungen in der aktuellen Literatur waren zum einen der Verzicht auf eine Computertomographie bei Verdacht auf Milztrauma, zum anderen das konservative Vorgehen trotz nachgewiesenem Kontrastmittelaustrit

    Physical Electronics and Surface Physics

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    Contains research objectives and reports on four research projects.National Aeronautics and Space Administration (Grant NGR-22-009-091)M. I. T. Cabot Solar Energy FundJoint Services Electronics Programs (U. S. Army, U.S. Navy, and U.S. Air Force) under Contract DA 36-039-AMC-03200(E

    Using Rheo-Small-Angle Neutron Scattering to Understand How Functionalised Dipeptides Form Gels

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    We explore the use of rheo-small-angle neutron scattering as a method to collect structural information from neutron scattering simultaneously with rheology to understand how low-molecular-weight hydrogels form and behave under shear. We examine three different gelling hydrogel systems to assess what structures are formed and how these influence the rheology. Furthermore, we probe what is happening to the network during syneresis and why the gels do not recover after an applied strain. All this information is vital when considering gels for applications such as 3D-printing and injection

    Dietary soy and meat proteins induce distinct physiological and gene expression changes in rats

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    This study reports on a comprehensive comparison of the effects of soy and meat proteins given at the recommended level on physiological markers of metabolic syndrome and the hepatic transcriptome. Male rats were fed semi-synthetic diets for 1 wk that differed only regarding protein source, with casein serving as reference. Body weight gain and adipose tissue mass were significantly reduced by soy but not meat proteins. The insulin resistance index was improved by soy, and to a lesser extent by meat proteins. Liver triacylglycerol contents were reduced by both protein sources, which coincided with increased plasma triacylglycerol concentrations. Both soy and meat proteins changed plasma amino acid patterns. The expression of 1571 and 1369 genes were altered by soy and meat proteins respectively. Functional classification revealed that lipid, energy and amino acid metabolic pathways, as well as insulin signaling pathways were regulated differently by soy and meat proteins. Several transcriptional regulators, including NFE2L2, ATF4, Srebf1 and Rictor were identified as potential key upstream regulators. These results suggest that soy and meat proteins induce distinct physiological and gene expression responses in rats and provide novel evidence and suggestions for the health effects of different protein sources in human diets

    Quantum-sl(2) action on a divided-power quantum plane at even roots of unity

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    We describe a nonstandard version of the quantum plane, the one in the basis of divided powers at an even root of unity q=eiπ/pq=e^{i\pi/p}. It can be regarded as an extension of the "nearly commutative" algebra C[X,Y]C[X,Y] with XY=(1)pYXX Y =(-1)^p Y X by nilpotents. For this quantum plane, we construct a Wess--Zumino-type de Rham complex and find its decomposition into representations of the 2p32p^3-dimensional quantum group Uqsl(2)U_q sl(2) and its Lusztig extension; the quantum group action is also defined on the algebra of quantum differential operators on the quantum plane.Comment: 18 pages, amsart++, xy, times. V2: a reference and related comments adde
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