2,995 research outputs found

    Island of Stability for Consistent Deformations of Einstein's Gravity

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    We construct explicitly deformations of Einstein's theory of gravity that are consistent and phenomenologically viable since they respect, in particular, cosmological backgrounds. We show that these deformations have unique symmetries in accordance with unitarity requirements, and give rise to a curvature induced self-stabilizing mechanism. As a consequence, any nonlinear completed deformation must incorporate self-stabilization on generic spacetimes already at lowest order in perturbation theory. Furthermore, our findings include the possibility of consistent and phenomenologically viable deformations of general relativity that are solely operative on curved spacetime geometries, reducing to Einstein's theory on the Minkowski background.Comment: 4 pages, 3 figures, v2: discussion of phenomenology and applications added, presentation optimize

    Preoperative CYFRA 21-1 and CEA as Prognostic Factors in Patients with Stage I Non-Small Cell Lung Cancer

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    Objective: To validate the prognostic value of preoperative levels of CYFRA 21-1, CEA and the corresponding tumor marker index (TMI) in patients with stage I non-small cell lung cancer (NSCLC). Methods: Two hundred forty stage I NSCLC patients (80 in pT1 and 160 in pT2; 100 squamous cell carcinomas, 91 adenocarcinomas, 32 large-cell carcinomas, 17 with other histologies; 171 males and 69 females) who had complete resection (R0) between 1986 and 2004 were included in the analysis. CYFRA 21-1 and CEA were measured using the Elecsys system (Roche) and AxSym-System (Abbott), respectively. Univariate analysis was performed using the Kaplan-Meier method to identify potential associations between survival and age, gender, CYFRA 21-1, CEA and TMI. Results: Overall 3- and 5-year survival rates were 74 and 64%, respectively. Male gender (p = 0.0009) and age 1 70 years (p = 0.0041) were associated with a worse prognosis; there were no differences between pT1 and pT2 nor between histological subtypes. Three- year survival was 72% for CYFRA 21-1 levels > 3.3 ng/ml versus 75% for levels 6.7 ng/ ml versus 75% for CEA 70 years were associated with a worse outcome, but elevated levels of CEA and CYFRA 21-1, and TMI risk were not. Copyright (C) 2008 S. Karger AG, Basel

    Morsels: Explicit Virtual Memory Objects

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    The tremendous growth of RAM capacity - now exceeding multiple terabytes - necessitates a reevaluation of traditional memory-management methods, which were developed when resources were scarce. Current virtual-memory subsystems handle address-space regions as sets of individual 4-KiB pages with demand paging and copy-on-write, resulting in significant management overhead. Although huge pages reduce the number of managed entities, they induce internal fragmentation and have a coarse copy granularity.To address these problems, we introduce Morsels, a novel virtual-memory-management paradigm that is purely based on hardware data structures and enables the efficient sharing of virtual-memory objects between processes and devices while being well suited for non-volatile memory. Our benchmarks show that Morsels reduce the mapping time for a 6.82-GiB machine-learning model by up to 99.8 percent compared to conventional memory mapping in Linux

    Vorrichtung zur lösbaren Verbindung eines Drahtes und Verfahren zum Ausbringen des Gerätes in ein Gewässer mit der Vorrichtung

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    Die Erfindung betrifft eine Vorrichtung zur lösbaren Verbindung eines Drahtes, insbesondere eines Tiefseedrahtes (1), mit einem Gerät, insbesondere Tiefseegerät (9), wobei eine Auslöseeinheit (11) zwischen dem Draht (1) und dem Gerät (9) vorgesehen ist, die zum bedarfsweisen Lösen der Verbindung des Drahts (1) mit dem Gerät (9) unter Wasser ausgebildet ist. Erfindungsgemäß sind zumindest ein erster und ein zweiter Transponder (4, 8) vorgesehen, die zwischen dem Draht (1) und der Auslöseeinheit (11) angeordnet sind, wobei der Draht (1) über eine Verbindung mit der Auslöseeinheit (11) verbunden ist und die Verbindung eine definierte Länge aufweist. Des Weiteren betrifft die Erfindung ein Verfahren zum Ausbringen des Gerätes (9) in ein Gewässer, insbesondere in Meerwasser, vorzugsweise in die Tiefsee, mit dieser Vorrichtung

    Comparison of radiation dose, workflow, patient comfort and financial break-even of standard digital radiography and a novel biplanar low-dose X-ray system for upright full-length lower limb and whole spine radiography

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    Objective: To compare the radiation dose, workflow, patient comfort, and financial break-even of a standard digital radiography and a biplanar low-dose X-ray system. Materials and methods: A standard digital radiography system (Ysio, Siemens Healthcare, Erlangen, Germany) was compared with a biplanar X-ray unit (EOS, EOS imaging, Paris, France) consisting of two X-ray tubes and slot-scanning detectors, arranged at an angle of 90° allowing simultaneous vertical biplanar linear scanning in the upright patient position. We compared data of standing full-length lower limb radiographs and whole spine radiographs of both X-ray systems. Results: Dose-area product was significantly lower for radiographs of the biplanar X-ray system than for the standard digital radiography system (e.g. whole spine radiographs; standard digital radiography system: 392.2 ± 231.7cGy*cm2 versus biplanar X-ray system: 158.4 ± 103.8cGy*cm2). The mean examination time was significantly shorter for biplanar radiographs compared with standard digital radiographs (e.g. whole spine radiographs: 449s vs 248s). Patients' comfort regarding noise was significantly higher for the standard digital radiography system. The financial break-even point was 2,602 radiographs/year for the standard digital radiography system compared with 4,077 radiographs/year for the biplanar X-ray unit. Conclusion: The biplanar X-ray unit reduces radiation exposure and increases subjective noise exposure to patients. The biplanar X-ray unit demands a higher number of examinations per year for the financial break-even point, despite the lower labour cost per examination due to the shorter examination tim

    Monitoring submarine fault deformation using direct-path ranging

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    The seafloor stores crucial information on sub-seafloor processes, including stress, elastic strain, and earthquakes. This information may be extracted through the nascent scientific field of seafloor geodesy. The GeoSEA (Geodetic Earthquake Observatory on the SEAfloor) array uses acoustic signals for direct-path ranging and relative positioning at mm-scale resolution for a period of up to 3.5 years. The transponders also include high-precision pressure sensors to monitor vertical movements and dual-axis inclinometers in order to measure their altitude as well as any change in submarine fault zones and characterizing their behavior (locked or aseismically creeping). A further component of the network is GeoSURF, a self-steering autonomous surface vehicle (Wave Glider), which monitors system health and is able to upload the seafloor data to the sea surface and to transfer it via satellite. Seafloor transponders are currently installed across a dextral strike-slip fault to measure the instability of the eastern flank of Mt Etna in Sicily, along the North Anatolian Fault offshore Istanbul to measure the strain build-up along the fault in a seismic gap. In addition, three arrays are currently deployed on the marine forearc and outer rise of the South American subduction system around 21°S. This segment of the Nazca-South American plate boundary has last ruptured in an earthquake in 1877 and was identified as a seismic gap prior to the 2014 Iquique earthquake (Mw 8.1). The southern portion of the segment remains unbroken by a recent earthquake. The first 12 month of all geodetic installations were analyzed and we discuss baselines with precision less 5 mm for ranges up to 2000 m of distance and compare them to synthetics baselines. The North Anatolian across-fault baseline changes remains within the resolution and preclude fault-displacement rates larger a few millimeters-per-year, which suggests a locked fault zone

    Differential Column Sensor Network in Munich and Low-Cost NOx Sensor Development

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