1,289 research outputs found

    Gravity Field Modeling Using Tesseroids with Variable Density in the Vertical Direction

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    We present an accurate method for the calculation of gravitational potential (GP), vector (GV), and gradient tensor (GGT) of a tesseroid, considering a density model in the form of a polynomial up to cubic order along the vertical direction. The method solves volume integral equations for the gravitational effects due to a tesseroid by the Gauss–Legendre quadrature rule. A two-dimensional adaptive subdivision technique, which automatically divides the tesseroids near the computation point into smaller elements, is applied to improve the computational accuracy. For those tesseroids having small vertical dimensions, an extension technique is additionally utilized to ensure acceptable accuracy, in particular for the evaluation of GV and GGT. Numerical experiments based on spherical shell models, for which analytical solutions exist, are implemented to test the accuracy of the method. The results demonstrate that the new method is capable of computing the gravitational effects of the tesseroids with various horizontal and vertical dimensions as well as density models, while the evaluation point can be on the surface of, near the surface of, outside the tesseroid, or even inside it (only suited for GP and GV). Thus, the method is attractive for many geodetic and geophysical applications on regional and global scales, including the computation of atmospheric effects for terrestrial and satellite usage. Finally, we apply this method for computing the topographic effects in the Himalaya region based on a given digital terrain model and the global atmospheric effects on the Earth’s surface by using three polynomial density models which are derived from the US Standard Atmosphere 1976

    Correction to: Gravity Field Modeling Using Tesseroids with Variable Density in the Vertical Direction

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    The article: “Gravity Field Modeling Using Tesseroids with Variable Density in the Vertical Direction”, written by Miao Lin, Heiner Denker and Jürgen Müller, was originally published electronically on the publisher’s internet portal on 26 March 2020 without open access

    Umweltberichterstattung von Unternehmen im Internet. Der aktuelle Stand fĂĽr Deutschland

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    Von den Umweltberichten deutscher Unternehmen werden bisher erst unter 3% im Internet veröffentlicht. Die Tendenz ist steigend. Hier werden die im Internet verfügbaren Umweltberichte ausgewertet und Gründe für die Nutzung des Internet für die Umweltberichterstattung vorgetragen. Der Beitrag ist in fünf Abschnitte gegliedert: Zur thematischen Einführung werden betriebliche Umweltberichte durch eine Morphologie charakterisiert (Abschnitt 2). Es schließen sich die IKT-spezifischen Herausforderungen an umweltberichterstattende Unternehmen als Ansatzpunkte für Umweltberichte im Internet an (Abschnitt 3). Damit ist die Basis für eine Systematisierung der internetbasierten Unterstützungspotenziale zur Umweltberichterstattung gelegt (Abschnitt 4). Der Systematik folgt eine detaillierte Bestandsaufnahme der Umweltberichte deutscher Unternehmen im Internet in fünffacher Hinsicht (Abschnitt 5): Die zugrunde gelegte Untersuchungsmethodik zur Bestandsaufnahme wird erläutert (Abschnitt 5.1). Die ergänzend herangezogenen empirischen Studien zu Umweltberichten im Internet werden ausgewertet (Abschnitt 5.2). Die Ergebnisse bzgl. Inhalt und Darstellung von Umweltberichten im Internet werden ausführlicher beschrieben (Abschnitt 5.3) und durch Erklärungsansätze interpretiert (Abschnitt 5.4). Abschließend werden auf der Grundlage der konzeptionell erschließbaren Unterstützungspotenziale einerseits und der empirischen Studien andererseits zentrale Tendenzen zur zukünftigen Entwicklung von Umweltberichten im Internet vorgetragen (Abschnitt 5.5)

    3D Tunnel Inspection with Photogrammetric and Hybrid Systems

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    The trend in tunnel assessment is towards comprehensive 3D measurement, either based on high quality digital imagery (photogrammetric systems) or the combination of laser and photo systems (hybrid systems). With digital 3D data, quantification and categorization of damage to the tunnel surface as well as the determination of thickness or volumes of layers (e.g. shotcrete) can performed in a comprehensive, fast and economic way. The faster such tunnel assessment can be executed on site, the lower are the tunnel block times and environmental impairments related to the building measures. The costs for the operating companies can be significantly reduced as well as the personnel efforts and risks of accidents. Furthermore, tunnel safety is increased due to faster test cycles which result in a more comprehensive overall monitoring. Please click Additional Files below to see the full abstract

    Strong gametocytocidal effect of methylene blue-based combination therapy against falciparum malaria

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    With the availability of new preventive and curative interventions, global malaria control has been strengthened significantly in recent years. Drugs effective in reducing malaria gametocytaemia might contribute to local elimination and possible long-term eradication. We here report on the effects of methylene blue (MB)-based malaria combination therapy on gametocytaemia during a randomised-controlled trial in Burkina Faso. An open-label randomised controlled phase II study in 180 children aged 6-10 years with uncomplicated falciparum malaria was conducted in Nouna, north-western Burkina Faso. Children were randomised to MB-artesunate (AS), MB-amodiaquine (AQ), and AS-AQ (local standard of care). Overall follow-up was for 28 days, follow-up for gametocytaemia was for 14 days. The treatment groups were similar in baseline characteristics and there was only one loss to follow-up. Compared to AS-AQ, both MB-containing regimens were associated with significantly reduced gametocyte carrier rates during follow-up days 3, 7, and 14. This effect was seen both in patients with and without P. falciparum gametocytaemia at baseline. MB reveals pronounced gametocytocidal activity which appears to act against both existing and developing P. falciparum gametocytes. MB-based combination therapy thus has the potential to reduce transmission of P. falciparum malaria in endemic regions, which has important implications for future elimination and eradication strategies

    Paediatric rehabilitation treatment standards: a method for quality assurance in Germany

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    Over the last few years, the German Pension Insurance has implemented a new method of quality assurance for inpatient rehabilitation of children and adolescents diagnosed with bronchial asthma, obesity, or atopic dermatitis: the so-called rehabilitation treatment standards (RTS). They aim at promoting a comprehensive and evidence-based care in rehabilitation. Furthermore, they are intended to make the therapeutic processes in medical rehabilitation as well as potential deficits more transparent. The development of RTS was composed of five phases during which current scientific evidence, expert knowledge, and patient expectations were included. Their core element is the specification of evidence-based treatment modules that describe a good rehabilitation standard for children diagnosed with bronchial asthma, obesity, or atopic dermatitis. Opportunities and limitations of the RTS as a tool for quality assurance are discussed

    Phase Field Modeling of Fast Crack Propagation

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    We present a continuum theory which predicts the steady state propagation of cracks. The theory overcomes the usual problem of a finite time cusp singularity of the Grinfeld instability by the inclusion of elastodynamic effects which restore selection of the steady state tip radius and velocity. We developed a phase field model for elastically induced phase transitions; in the limit of small or vanishing elastic coefficients in the new phase, fracture can be studied. The simulations confirm analytical predictions for fast crack propagation.Comment: 5 pages, 11 figure

    Content validity, interpretability, and internal consistency of the “Quality First” assessment to evaluate movement quality in hop tests following ACL rehabilitation. A cross-sectional study

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    Introduction: Current approaches fail to adequately identify sport readiness after anterior cruciate ligament (ACL) rehabilitation. Altered landing biomechanics after ACL reconstruction are associated with increased risk of a noncontact ACL reinjury. There is a lack of objective factors to screen for deficient movement patterns. Therefore, the aim of this study was to investigate content validity, interpretability, and internal consistency for the newly developed "Quality First" assessment to evaluate movement quality during hop tests in patients after ACL rehabilitation. Method: Participants in this cross-sectional study were recruited in collaboration with the Altius Swiss Sportmed Center in Rheinfelden, Switzerland. After a successful ACL reconstruction, the movement quality of 50 hop test batteries was evaluated between 6 and 24 months postoperatively with the "Quality First" assessment. Content validity was assessed from the perspective of professionals. To check the interpretability, classical test theory was employed. Cronbach's α was calculated to evaluate internal consistency. Results: Content validity resulted in the inclusion of three different hop tests (single-leg hop for distance, vertical hop, and side hop). The "Quality First" assessment is enabled to evaluate movement quality in the sagittal, vertical, and the transversal plane. After the exclusion process, the "Quality First" assessment was free from floor and ceiling effects and obtained a sufficient Cronbach's α. The final version consists of 15 items, rated on a 4-point scale. Discussion: By means of further validations, the "Quality First" assessment could offer a possibility to evaluate movement quality after ACL rehabilitation during hop tests

    Tumour Fas ligand:Fas ratio greater than 1 is an independent marker of relative resistance to tamoxifen therapy in hormone receptor positive breast cancer

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    BACKGROUND: The objective of the present study was to examine the prognostic and predictive significance of the apoptosis-related marker Fas ligand (FasL):Fas ratio in breast cancer. METHODS: Tumour biopsies from 215 primary invasive breast cancer patients were examined for the expression of FasL and Fas mRNA transcripts by quantitative real-time RT-PCR. Their prognostic and predictive impact on patient survival was determined in univariate and multivariate survival analyses. RESULTS: Using a cutoff value of 1, a FasL:Fas ratio greater than 1 was found to have significant prognostic value for disease-free survival among the total population (median follow up 54 months). It was associated with a significantly decreased disease-free survival (P = 0.022) and with a tendency toward increased mortality (P = 0.14) in univariate analysis. Hormone receptor positive women exclusively treated with tamoxifen (n = 86) and with a FasL:Fas ratio greater than 1 had a significantly decreased disease-free survival (P = 0.008) and overall survival (P = 0.03) in univariate Kaplan–Meier analysis. Furthermore, tumour size and FasL:Fas ratio were of independent predictive significance in the multivariate model for disease-free and overall survival in that subgroup. Among postmenopausal patients (n = 148) both of those factors retained independent prognostic significance in the multivariate model for disease-free survival. In contrast, FasL:Fas ratio had no significant predictive value in patients exclusively treated with chemotherapy. CONCLUSION: The data presented indicate that FasL:Fas ratio may be useful not only as a prognostic factor but also as a predictive factor for projecting response to the antioestrogen tamoxifen. The results strongly support a correlation between FasL:Fas ratio greater than 1 and lack of efficacy of tamoxifen in hormone receptor positive patients
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