99 research outputs found

    Anforderungen an den Anzeigenverkauf in der aktuellen Wirtschaftssituation unter besonderer BerĂĽcksichtigung einer regionalen Wochenkaufzeitung

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    Ziel der Bachelorarbeit ist es, den Beruf und die Aufgabenbereiche eines Anzeigenverkäufers genauer zu definieren und Lösungsansätze für die Optimierung der Tätigkeitsfelder des Anzeigenverkaufs zu finden. Erfolgreicher Anzeigenverkauf in Zeiten der Krise, welche Kunden- und Geschäftsbereiche bieten noch Ressourcen, welche Voraussetzungen sind dazu nötig? Gibt es Möglichkeiten und Maßnahmen, Überforderungen und Stressfaktoren, die bei den Mitarbeitern in dieser Branche immer mehr zunehmen, zu vermindern

    Development and testing of the 3U+ CubeSat PCDU for SOURCE

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    SOURCE (Stuttgart Operated University CubeSat for Evaluation and Education) is a 3U+ re-search CubeSat that is being developed by students at the University of Stuttgart in coopera-tion with the Institute for Space Systems and the Small Satellite Student Society KSat e.V.. The objectives include technology demonstrations, atmospheric research and the investigation of satellite demise while also serving as an educational program. SOURCE was selected by ESA's "Fly your Satellite" program and is currently in Phase D. The electrical power supply system combines commercial off-the-shelf parts with self-devel-oped units to meet the requirements of the payloads. The solar array configuration and Power Conditioning and Distribution Unit (PCDU) are self-developed, while the battery is a commer-cial product. A total of 56 solar cells provides up to 32W under ideal conditions, which can be stored in a 75Wh space-qualified lithium-ion battery. To maximise the power output of the solar cells, maximum power point tracking is performed by the PCDU. This is controlled by a radiation hardened microcontroller. The PCDU provides regulated 3.3V, 5V and unregulated battery voltage to the subsystems with 32 switchable outputs, 27 of which are latch-up current protected. The microcontroller controls these individual output channels and the switching between the various CubeSat modes as commanded by the on-board computer. Additionally, every output channel power consumption is monitored for overcurrents. The PCDU functions as a watchdog by checking the health of the on-board computer, rebooting it in case of a failure. High priority commands can be sent directly to the PCDU from the ground via the communication system, bypassing the on-board computer. These can reset either the communication subsystem, the on-board computer or the entire satellite. Four hybrid inhibits, using a combination of mechanical switches and FETs are integrated in the PCDU, replacing the usual fully mechanical design. Three are used to deactivate the satellite in the deployer configuration and the fourth is a remove-before-flight inhibit. An engineering model was manufactured during phase C and is being tested functionally, en-vironmentally and for performance. This paper presents the detailed design of the PCDU, the acquired test results and outlines issues encountered during the test

    Shrubland primary production and soil respiration diverge along European climate gradient

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    imbalance p paper contact with: Marc Estiarte, [email protected] and belowground carbon (C) stores of terrestrial ecosystems are vulnerable to environmental change. Ecosystem C balances in response to environmental changes have been quantified at individual sites, but the magnitudes and directions of these responses along environmental gradients remain uncertain. Here we show the responses of ecosystem C to 8-12 years of experimental drought and night-time warming across an aridity gradient spanning seven European shrublands using indices of C assimilation (aboveground net primary production: aNPP) and soil C efflux (soil respiration: Rs). The changes of aNPP and Rs in response to drought indicated that wet systems had an overall risk of increased loss of C but drier systems did not. Warming had no consistent effect on aNPP across the climate gradient, but suppressed Rs more at the drier sites. Our findings suggest that above- and belowground C fluxes can decouple, and provide no evidence of acclimation to environmental change at a decadal timescale. aNPP and Rs especially differed in their sensitivity to drought and warming, with belowground processes being more sensitive to environmental change

    Comparison of the Low-Cost Sun Sensors of the SOURCE and EIVE CubeSats

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    Sun sensors are commonly used attitude determination equipment which measure a spacecraft’s attitude relative to the sun. Multiple types of low-cost sun sensors were developed for the SOURCE and EIVE CubeSats. The SOURCE sun sensors consist of single photodiodes which are placed in a one-sensor-per-face as well as a pyramid arrangement. EIVE employs digital vector sun sensors based on quad-pin photodiodes. The SOURCE sun sensors in the one-sensor-per-face arrangement archive an accuracy of \u3c10° while the pyramid arrangement accomplishes an accuracy of \u3c7.5° without and \u3c5° with calibration. EIVE’s vector sun sensors offer an raw accuracy of 3°±5°. Multiple calibration approaches are presented with the best results leading to an accuracy of 0.7±3°. A direct comparison between the SOURCE and EIVE sensor types and configurations can be drawn since the same test bench was used to measure all sensors. The objective of this paper is to present and compare the different sun sensor concepts and their results

    The EIVE CubeSat - Developing a Satellite Bus for a 71-76 GHz E-Band Transmitter Payload

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    A high-speed data downlink system provides many challenges for a CubeSat design. Two major aspect are an adequate power management as well as the thermal implications of the dissipated power. The goal of the 6U CubeSat EIVE is to prove the feasibility of an E-band link at 71-76 GHz and explore the influence of different atmospheric conditions on the link quality. The requirements of the E-band transmitter in terms of mass, volume, power and pointing accuracy outline the specific constraints imposed on the design of the satellite bus. The major design drivers of the system are the peak power demand of 60 W for the payload itself and the required pointing accuracy of less than 1â—¦. To cope with these demands, general design considerations, the choice of the orbit and the operation of the satellite are discussed. A special focus is the power generation and consumptions by means of a dynamic attitude and power simulation. The thermal simulation is verified by building a detailed structural and thermal replica of the satellite to investigate the heat dissipation. An overview of the current EIVE CubeSat platform design concludes this paper

    Mitochondrial Haplogroups, Control Region Polymorphisms and Malignant Melanoma: A Study in Middle European Caucasians

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    Because mitochondria play an essential role in energy metabolism, generation of reactive oxygen species (ROS), and apoptosis, sequence variation in the mitochondrial genome has been postulated to be a contributing factor to the etiology of multifactorial age-related diseases, including cancer. The aim of the present study was to compare the frequencies of mitochondrial DNA (mtDNA) haplogroups as well as control region (CR) polymorphisms of patients with malignant melanoma (n = 351) versus those of healthy controls (n = 1598) in Middle Europe.Using primer extension analysis and DNA sequencing, we identified all nine major European mitochondrial haplogroups and known CR polymorphisms. The frequencies of the major mitochondrial haplogroups did not differ significantly between patients and control subjects, whereas the frequencies of the one another linked CR polymorphisms A16183C, T16189C, C16192T, C16270T and T195C were significantly higher in patients with melanoma compared to the controls. Regarding clinical characteristics of the patient cohort, none of the nine major European haplogroups was associated with either Breslow thickness or distant metastasis. The CR polymorphisms A302CC-insertion and T310C-insertion were significantly associated with mean Breslow thickness, whereas the CR polymorphism T16519C was associated with metastasis.Our results suggest that mtDNA variations could be involved in melanoma etiology and pathogenesis, although the functional consequence of CR polymorphisms remains to be elucidated

    Building in China - Study trip of the faculty of Civil Engineering of the HTWG Konstanz 2008

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    Im März 2008 führte die Fakultät Bauingenieurwesen der HTWG Konstanz eine studentische Exkursion nach China durch. Auf dem Programm standen interessante Baustellen Shanghai, Nanjing, Zhenjiang und Beijing sowie der Besuch von Hochschulen. Der Exkursionsbericht beschreibt die besuchten Bauvorhaben und gibt persönliche Eindrücke der Exkursionsteilnehmer wieder.In March 2008 the faculty of civil engineering of the University of Applied Sciences Konstanz, Germany, conducted a study trip for students of civil engineering to China. Construction sites and universities in Shanghai, Nanjing, Zhenjiang and Beijing have been visited. The report describes the places seen and reflects the personal impressions of the participants

    Shrubland primary production and soil respiration diverge along European climate gradient

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    Above- and belowground carbon (C) stores of terrestrial ecosystems are vulnerable to environmental change. Ecosystem C balances in response to environmental changes have been quantified at individual sites, but the magnitudes and directions of these responses along environmental gradients remain uncertain. Here we show the responses of ecosystem C to 8–12 years of experimental drought and night-time warming across an aridity gradient spanning seven European shrublands using indices of C assimilation (aboveground net primary production: aNPP) and soil C efflux (soil respiration: Rs). The changes of aNPP and Rs in response to drought indicated that wet systems had an overall risk of increased loss of C but drier systems did not. Warming had no consistent effect on aNPP across the climate gradient, but suppressed Rs more at the drier sites. Our findings suggest that above- and belowground C fluxes can decouple, and provide no evidence of acclimation to environmental change at a decadal timescale. aNPP and Rs especially differed in their sensitivity to drought and warming, with belowground processes being more sensitive to environmental change
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