2,756 research outputs found

    Ein Reifegradmodell für Business-Intelligence-Lösungen

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    Zusammenfassung: Die steigende Bedeutung von Business Intelligence (BI) für die Steuerung und Wettbewerbsfähigkeit von Unternehmen erfordert eine kontinuierliche, transparente und detaillierte Bewertung der BI-Lösungen in den Organisationen. Zu diesem Zweck wurde das BI-spezifische Reifegradmodell biMM (Business Intelligence Maturity Model) entwickelt. Im Beitrag werden dessen fünf Reifegradstufen in den Dimensionen Fachlichkeit, Technik und Organisation beschrieben. Auswertungen einer Studie, basierend auf biMM, zeigen den State of the Art von BI-Lösungen im deutschsprachigen Raum. Die durchschnittliche Reife der Unternehmen ist der dritten Stufe zuzuordnen. Aus den geplanten BI-Aktivitäten und dem zukünftig prognostizierten Reifegrad lassen sich Trends und künftige Herausforderungen für Praxis und Wissenschaft gleichermaßen ableiten. Dazu zählen aufbauorganisatorische Maßnahmen, wie die Einrichtung eines BI-Competence-Centers, ein stärkerer Fokus auf die Wirtschaftlichkeit und ein verbesserter Wirkungsgrad der BI-Architektu

    Remote sensing of coccolithophore blooms in selected oceanic regions using the PhytoDOAS method applied to hyper-spectral satellite data

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    In this study temporal variations of coccolithophore blooms are investigated using satellite data. Eight years (from 2003 to 2010) of data of SCIAMACHY, a hyper-spectral satellite sensor on-board ENVISAT, were processed by the PhytoDOAS method to monitor the biomass of coccolithophores in three selected regions. These regions are characterized by frequent occurrence of large coccolithophore blooms. The retrieval results, shown as monthly mean time series, were compared to related satellite products, including the total surface phytoplankton, i.e. total chlorophyll a (from GlobColour merged data) and the particulate inorganic carbon (from MODIS-Aqua). The inter-annual variations of the phytoplankton bloom cycles and their maximum monthly mean values have been compared in the three selected regions to the variations of the geophysical parameters: sea-surface temperature (SST), mixed-layer depth (MLD) and surface wind-speed, which are known to affect phytoplankton dynamics. For each region, the anomalies and linear trends of the monitored parameters over the period of this study have been computed. The patterns of total phytoplankton biomass and specific dynamics of coccolithophore chlorophyll a in the selected regions are discussed in relation to other studies. The PhytoDOAS results are consistent with the two other ocean color products and support the reported dependencies of coccolithophore biomass dynamics on the compared geophysical variables. This suggests that PhytoDOAS is a valid method for retrieving coccolithophore biomass and for monitoring its bloom developments in the global oceans. Future applications of time series studies using the PhytoDOAS data set are proposed, also using the new upcoming generations of hyper-spectral satellite sensors with improved spatial resolution

    Application of Ewald's Method for Efficient Summation of Dyon Long-Range Potentials

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    We study a model of dyons for SU(2) Yang-Mills theory at finite temperature T < T_c, in particular its ability to generate a confining force between a static quark antiquark pair. The interaction between dyons corresponds to a long-range 1/r potential, which in naive treatments with a finite number of dyons typically gives rise to severe finite volume effects. To avoid such effects we apply the so-called Ewald method, which has its origin in solid state physics. The basic idea of Ewald's method is to consider a finite number of dyons inside a finite cubic volume and enforce periodicity of this volume. We explain the technicalities of Ewald's method and outline how the method can be applied to a wider class of 1/r^p long-range potentials.Comment: 8 pages, 4 figures, contribution to conference "Confinement X

    Carbohydrate receptor-mediated gene transfer to human T leukaemic cells

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    The mucin-type carbohydrate Tn cryptantigen (GalNAcα1-O-Ser/Thr, where GalNAc is N-acetyl-D-galactosamine) is expressed in many carcinomas, in haemopoietic disorders including the Tn syndrome, and on human immunodeficiency virus (HIV) coat glycoproteins, but is not expressed on normal, differentiated cells because of the expression of a Tn-processing galactosyltransferase. Using Jurkat T leukaemic cells which express high levels of Tn antigen due to deficient Tn galactosylation, we have established the Tn antigen-mediated gene transfer and demonstrate the considerable efficiency of this approach. We used poly(L-lysine) conjugates of the monoclonal antibody 1E3 directed against the Tn antigen to deliver the luciferase and β-galactosidase reporter genes to Jurkat cells by receptor-mediated endocytosis. Addition of unconjugated 1E3 reduced transfection efficiency in a concentration-dependent manner and incubation with free GalNAc abolished DNA transfer completely, indicating that gene delivery is indeed mediated by the Tn antigen. Pre-treatment of Jurkat cells with Vibrio cholerae sialidase, which uncovers additional Tn antigens, resulted in an improvement of gene transfection. Both human and chicken adenovirus particles attached to the DNA/polylysine complex strongly augmented transgene expression. When the β-galactosidase (lacZ) gene was delivered to Jurkat cells by Tn-mediated endocytosis, up to 60% of the cells were positive in the cytochemical stain using 5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside (X-gal) as a chromogenic substrate. The efficiency of the transferrin receptor-mediated DNA uptake into Jurkat cells was comparatively low, although these cells were shown to express considerable amounts of transferrin receptor. We show here that a mucin-type carbohydrate antigen mediates highly efficient DNA uptake by endocytosis into Jurkat T cells. This method represents a 50-fold improvement of Jurkat cell transfection efficiency over other physical gene transfer techniques. Specific gene delivery to primary cancer cells exhibiting Tn epitopes may especially be desirable in immunotherapy protocol

    Spectral studies of ocean water using DOAS

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    International audienceMethods enabling the retrieval of oceanic parameter from the space borne instrumentation Scanning Imaging Absorption Spectrometer for Atmospheric ChartographY (SCIAMACHY) using Differential Optical Absorption Spectroscopy (DOAS) are presented. SCIAMACHY onboard ENVISAT measures back scattered solar radiation at a spectral resolution (0.2 to 1.5 nm). The DOAS method was used for the first time to fit modelled Vibrational Raman Scattering (VRS) in liquid water and in situ measured phytoplankton absorption reference spectra to optical depths measured by SCIAMACHY. Spectral structures of VRS and phytoplankton absorption were clearly found in these optical depths. Both fitting approaches lead to consistent results. DOAS fits correlate with estimates of chlorophyll concentrations: low fit factors for VRS retrievals correspond to large chlorophyll concentrations and vice versa; large fit factors for phytoplankton absorption correspond with high chlorophyll concentrations and vice versa. From these results a simple retrieval technique taking advantage of both measurements is shown. First maps of global chlorophyll concentrations were compared to the corresponding MODIS measurements with very promising results. In addition, results from this study will be used to improve atmospheric trace gas DOAS-retrievals from visible wavelengths by including these oceanographic signatures

    Mechanisms of HIV Protein Degradation into Epitopes: Implications for Vaccine Design

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    The degradation of HIV-derived proteins into epitopes displayed by MHC-I or MHC-II are the first events leading to the priming of HIV-specific immune responses and to the recognition of infected cells. Despite a wealth of information about peptidases involved in protein degradation, our knowledge of epitope presentation during HIV infection remains limited. Here we review current data on HIV protein degradation linking epitope production and immunodominance, viral evolution and impaired epitope presentation. We propose that an in-depth understanding of HIV antigen processing and presentation in relevant primary cells could be exploited to identify signatures leading to efficient or inefficient epitope presentation in HIV proteomes, and to improve the design of immunogens eliciting immune responses efficiently recognizing all infected cells

    Моделі динаміки пружних збурень у неоднорідно деформованому континуумі

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    Розвинуто нелінійну теорію пружності стосовно задач томографії тензорних полів у неоднорідно деформованих твердих тілах. За визначальні параметри локального термодинамічного стану, що відповідають процесові деформування, прийнято тензорні характеристики, означені щодо актуальної (деформованої) конфігурації — тензор напружень Коші та міри деформації Альманзі або Фінґера. У рамках запропонованої нелінійної теорії побудовано декілька варіантів системи рівнянь динаміки малих пружних збурень у неоднорідно деформованому твердому континуумі, лінеаризованої стосовно деформації збурення. Коефіцієнти отриманих рівнянь залежать від локальних параметрів початкового напружено-деформованого стану, заданих в актуальній конфігурації. У такому вигляді їх зручно застосовувати для опису хвильових процесів, які збуджують у неоднорідно деформованих тілах, щоб отримати апостеріорну інформацію про актуальний напружено-деформований стан цих об’єктів.A nonlinear theory of elasticity as applied to problems of tensor fields tomography in non-uniformly strained solids has been developed. As constitutive thermodynamic parameters of the theory, corresponding the process of deformation, the tensor characteristics determinate in the actual configuration — tensors Almansi’s and Finger’s have been used. In the frame of the theory several variants of system equations for dynamics of small elastic disturbances in non-uniformly strained continuum, linearized with respect to the amplitude of the disturbance, have been built. These equations coefficients are depended on local parameters of the body stress-strained state, determined in local base of the actual configuration. In such a form they are convenient to use for describing of the wave processes in non-uniformly strained solids activated to obtain some a posteriori information about the actual stress-strained state of such objects.Развита нелинейная теория упругости применительно к задачам томографии тензорных полей в неоднородно деформированных твердых телах. В качестве определяющих параметров локального термодинамического состояния, соответствующих процессу деформирования, приняты тензорные характеристики, определяемые относительно актуальной (деформированной) конфигурации — тензор напряжений Коши и меры деформации Альманзи или Фингера. В рамках предложенной нелинейной теории построено несколько вариантов системы уравнений динамики малых упругих возмущений в неоднородно деформированном твердом континууме, линеаризированной относительно деформации возмущения. Коэффициенты полученных уравнений зависят от локальных параметров напряженно-деформированного состояния, заданных в актуальной конфигурации. В таком виде их удобно применять для описания волновых процессов, которые возбуждают в неоднородно деформированных телах для получения апостериорной информации об актуальном напряженно-деформированном состоянии этих объектов

    Cloud and surface classification using SCIAMACHY polarization measurement devices

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    International audienceA simple scheme has been developed to discriminate surface, sun glint and cloud properties in satellite based spectrometer data utilizing visible and near infrared information. It has been designed for the use with data measured by SCIAMACHY's (SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY) Polarization Measurement Devices but the applicability is not strictly limited to this instrument. The scheme is governed by a set of constraints and thresholds developed by using satellite imagery and meteorological data. Classification targets are ice, water and generic clouds, sun glint and surface parameters, such as water, snow/ice, desert and vegetation. The validation is done using MERIS (MEdium Resolution Imaging Spectrometer) and meteorological data from METAR (MÉTéorologique Aviation Régulière ? a network for the provision of meteorological data for aviation). Qualitative and quantitative validation using MERIS satellite imagery shows good agreement. The comparison with METAR data exhibits very good agreement

    Using empirical orthogonal functions derived from remote sensing reflectance for the prediction of concentrations of phytoplankton pigments.

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    The composition and abundance of algal pigments provide information on characteristics of a phytoplankton community in respect to its photoacclimation, overall biomass, and taxonomic composition. Particularly, these pigments play a major role in photoprotection and in the light-driven part of photosynthesis. Most phytoplankton pigments can be measured by High Performance Liquid Chromatography (HPLC) techniques to filtered water samples. This method, like others when water samples have to be analysed in the laboratory, is time consuming and therefore only a limited number of data points can be obtained. In order to receive information on phytoplankton pigment composition with a higher temporal and spatial resolution, we have developed a method to assess pigment concentrations from continuous optical measurements. The method applies an Empirical Orthogonal Function (EOF) analysis to remote sensing reflectance data derived from ship-based hyper-spectral underwater radiometric and from multispectral satellite data (using the MERIS Polymer product developed by Steinmetz et al., 2011) measured in the Eastern Tropical Atlantic. Subsequently we developed statistically linear models with measured (collocated) pigment concentrations as the response variable and EOF loadings as predictor variables. The model results, show that surface concentrations of a suite of pigments and pigment groups can be well predicted from the ship-based reflectance measurements, even when only a multi-spectral resolution is chosen (i.e. eight bands similar to those used by MERIS). Based on the MERIS reflectance data, concentrations of total and monovinyl chlorophyll a and the groups of photoprotective and photosynthetic carotenoids can be predicted with high quality. The fitted statistical model constructed on the satellite reflectance data as input was applied to one month of MERIS Polymer data to predict the concentration of those pigment groups for the whole Eastern Tropical Atlantic area. Bootstrapping explorations of cross-validation error indicate that the method can produce reliable predictions with relatively small data sets (e.g., < 50 collocated values of reflectance and pigment concentration). The method allows for the derivation of time series from continuous reflectance data of various pigment groups at various regions, which can be used to study variability and change of phytoplankton composition and photo-physiology
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