304 research outputs found

    Compact Totally Disconnected Moufang Buildings

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    Let Δ\Delta be a spherical building each of whose irreducible components is infinite, has rank at least 2 and satisfies the Moufang condition. We show that Δ\Delta can be given the structure of a topological building that is compact and totally disconnected precisely when Δ\Delta is the building at infinity of a locally finite affine building.Comment: To appear in Tohoku Math. Journa

    An open tool for creating battery-electric vehicle time series from empirical data -- emobpy

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    There is substantial research interest in how future fleets of battery-electric vehicles will interact with the power sector. To this end, various types of energy models depend on meaningful input parameters, in particular time series of vehicle mobility, driving electricity consumption, grid availability, or grid electricity demand. As the availability of such data is highly limited, we introduce the open-source tool emobpy. Based on mobility statistics, physical properties of vehicles, and other customizable assumptions, it derives time series data that can readily be used in a wide range of model applications. For an illustration, we create and characterize 200 battery-electric vehicle profiles for Germany. Depending on the hour of the day, a fleet of one million vehicles has a median grid availability between 5 and 7 gigawatts, as vehicles are parking most of the time. Four exemplary grid electricity demand time series illustrate the smoothing effect of balanced charging strategies

    Transport in the 3-dimensional Anderson model: an analysis of the dynamics on scales below the localization length

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    Single-particle transport in disordered potentials is investigated on scales below the localization length. The dynamics on those scales is concretely analyzed for the 3-dimensional Anderson model with Gaussian on-site disorder. This analysis particularly includes the dependence of characteristic transport quantities on the amount of disorder and the energy interval, e.g., the mean free path which separates ballistic and diffusive transport regimes. For these regimes mean velocities, respectively diffusion constants are quantitatively given. By the use of the Boltzmann equation in the limit of weak disorder we reveal the known energy-dependencies of transport quantities. By an application of the time-convolutionless (TCL) projection operator technique in the limit of strong disorder we find evidence for much less pronounced energy dependencies. All our results are partially confirmed by the numerically exact solution of the time-dependent Schroedinger equation or by approximative numerical integrators. A comparison with other findings in the literature is additionally provided.Comment: 23 pages, 10 figure

    Anwendungen des maschinellen Lernens in der Produktion aus Auftrags- und Produktsicht : Ein Überblick

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    Machine learning as a subfield of artificial intelligence can contribute to accelerating the design of processes in manufacturing, reducing cycle times, improving quality, and making better use of production capacities. This article provides a systematized overview of machine learning applications for product- and order-related processes and supports practitioners in identifying application areas in a focused manner and exploiting valueadded potential.Das maschinelle Lernen als Teilgebiet der Künstlichen Intelligenz kann in der Fertigung dazu beitragen, Prozesse beschleunigt auszulegen, Zykluszeiten und Ausschuss zu reduzieren und Produktionskapazitäten besser auszuschöpfen. Dieser Beitrag gibt einen systematisierten Überblick über Anwendungen des maschinellen Lernens für produkt- und auftragsbezogene Prozesse und unterstützt Praxisanwender dabei, Einsatzfelder gezielt zu identifizieren und Wertschöpfungspotenziale zu erschließen

    High-resolution nerve ultrasound abnormalities in POEMS syndrome: a comparative study

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    Background: High-resolution nerve ultrasound (HRUS) has been proven to be a valuable tool in the diagnosis of immune-mediated neuropathies, such as chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, M-protein, skin changes) is an important differential diagnosis of CIDP. Until now, there have been no studies that could identify specific HRUS abnormalities in POEMS syndrome patients. Thus, the aim of this study was to assess possible changes and compare findings with CIDP patients. Methods: We retrospectively analyzed HRUS findings in three POEMS syndrome and ten CIDP patients by evaluating cross-sectional nerve area (CSA), echogenicity and additionally calculating ultrasound pattern scores (UPSA, UPSB, UPSC and UPSS) and homogeneity scores (HS). Results: CIDP patients showed greater CSA enlargement and higher UPSS (median 14 vs. 11), UPSA (median 11.5 vs. 8) and HS (median 5 vs. 3) compared with POEMS syndrome patients. However, every POEMS syndrome patient illustrated enlarged nerves exceeding reference values, which were not restricted to entrapment sites. In CIDP and POEMS syndrome, heterogeneous enlargement patterns could be identified, such as inhomogeneous, homogeneous and regional nerve enlargement. HRUS in CIDP patients visualized both increased and decreased echointensity, while POEMS syndrome patients pictured hypoechoic nerves with hyperechoic intraneural connective tissue. Discussion: This is the first study to demonstrate HRUS abnormalities in POEMS syndrome outside of common entrapment sites. Although nerve enlargement was more prominent in CIDP, POEMS syndrome patients revealed distinct echogenicity patterns, which might aid in its differentiation from CIDP. Future studies should consider HRUS and its possible role in determining diagnosis, prognosis and treatment response in POEMS syndrome

    Parotid Gland Stem Cell Sparing Radiation Therapy for Patients With Head and Neck Cancer:A Double-Blind Randomized Controlled Trial

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    BACKGROUND: Radiotherapy for head and neck cancer (HNC) frequently leads to salivary gland damage and subsequent xerostomia. The radiation response of parotid glands of rats, mice, and patients critically depends on dose to its stem cells, mainly located in the gland's main ducts (stem cell rich (SCR) region). Therefore, this double-blind randomized controlled trial aimed to test the hypothesis that parotid gland stem cell sparing radiotherapy preserves parotid gland function better than currently-used whole parotid gland sparing radiotherapy. METHODS: HNC patients (n=102) treated with definitive radiotherapy were randomized between standard parotid sparing and stem cell sparing (SCS) techniques. The primary endpoint was >75% reduction in parotid gland saliva production compared to pretreatment production (FLOW12M). Secondary endpoints were several aspects of xerostomia 12 months after treatment. RESULTS: Fifty-four patients were assigned to the standard arm and 48 to the SCS arm. Only dose to the SCR regions (contralateral 16 and 11 Gy (p=0.004) and ipsilateral 26 and 16 Gy (p=0.001), standard and SCS arm respectively) and pretreatment patient-rated daytime xerostomia (35% and 13% (p=0.01), standard and SCS arm respectively) differed significantly between the arms. In the SCS arm, 1 patient (2.8%) experienced FLOW12M compared to 2 (4.9%) in the standard arm (p=1.00). However, a trend towards better relative parotid gland salivary function in favor of SCS radiotherapy was shown. Moreover, multivariable analysis showed that mean contralateral SCR region dose was the strongest dosimetric predictor for moderate-to-severe patient-rated daytime xerostomia and grade ≥2 physician-rated xerostomia, the latter including complaints of alteration in diet. CONCLUSIONS: No significant better parotid function was observed in SCS radiotherapy. However, additional multivariable analysis showed that dose to the SCR region was more predictive for development of parotid gland function related xerostomia endpoints, than dose to the entire parotid gland
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