4,143 research outputs found

    Characterization of an in-vacuum PILATUS 1M detector

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    A dedicated in-vacuum X-ray detector based on the hybrid pixel PILATUS 1M detector has been installed at the four-crystal monochromator beamline of PTB at the electron storage ring BESSY II in Berlin. Due to its windowless operation, the detector can be used in the entire photon energy range of the beamline from 10 keV down to 1.75 keV for small-angle X-ray scattering (SAXS) experiments and anomalous SAXS (ASAXS) at absorption edges of light elements. The radiometric and geometric properties of the detector like quantum efficiency, pixel pitch and module alignment have been determined with low uncertainties. The first grazing incidence SAXS (GISAXS) results demonstrate the superior resolution in momentum transfer achievable at low photon energies.Comment: accepted by Journal of Synchrotron Radiatio

    Diversität epiphytischer Moose eines westandinen Bergregenwaldes in Ecuador

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    In einem Bergregenwald 110 km SW Quito in etwa 2000 m Höhe wurden die epiphytischen Moose des Stamm- und Kronenbereichs untersucht. Insgesamt wurden an 10 Bäumen 65 Arten (24 Laubmoos-, 41 Lebermoosarten) festgestellt. Die Moosflora der Stammbereiche zeigt bei 14 Arten insgesamt Übereinstimmungen bis zu 80% in der Artenzusammensetzung. Die Moosflora der Äste besteht aus 58 Arten. Bis auf die Äste derselben Bäume weisen die Äste unterschiedlicher Bäume nur eine Übereinstimmung von < 40% auf. Bei den untersuchten Zweigen ist die Übereinstimmung noch geringer. Auf ihnen wurden 24 Arten gefunden. Korrelationsanalysen zwischen Standortfaktoren und der Artenzahl wiesen keine signifikanten Beziehungen zwischen der Artenzahl und der Astdicke, der Astinklination und der Meereshöhe auf. Dagegen besteht eine Korrelation zwischen abnehmender Artenzahl und zunehmendem pH-Wert der Borke. Das durchschnittliche Trockengewicht der epiphytischen Moose beträgt im Stammbereich 80g/m2, im Astbereich 1873 g/m2 und im Zweigbereich 1230 g/m2. Die durchschnittliche Wasserspeicherkapazität epiphytischer Moose beträgt im Stammbereich 0,57 l/m2, im Astbereich 19,5 l/m2 und im Zweigbereich 4,16 l/m2, d.h. im Astbereich das Zehnfache des Trockengewichtes, im Zweigbereich das Dreifache. Ein mittlerer 27 m hoher Baum trägt im Durchschnitt 65,4 kg Trockengewicht epiphytischer Moose, die 669 l Wasser speichern können. Die Phytomasse pro Hektar wird auf 10600 kg geschätzt.The epiphytic bryophytes on tree trunks as well on branches and twigs of the canopy were studied in a montane rain forest in the Andes 110 km SW of Quito at about 2000 m elevation. Ten trees were examined on which 65 species (24 mooses and 41 liverworts) were found. The bryophyte flora of the stems consists of 14 species and is related on a level of up to 80%. The branches are inhabited by 58 species. The composition of species on branches of different trees (except those from the same trees) have a correspondence of less than 40%. The correspondence of the bryophytes on twigs of different trees is even lower. Twigs are inhabited by 24 species. Correlation analysis between species numbers and ecological factors revealed no significant correlation between species number and branch diameter, branch exposition and elevation. However, a correlation was found between increasing pH of the bark and decreasing species numbers. The average dry weight of epiphytic bryophytes was 80g/m2 on trunks, 1873 g/m2 on branches and 1230 g/m2 on twigs. The average water storing capacity of epiphytic bryophytes is 0.57 l/m2 on trunks, 19,5l/m2 on branches and 4.16 l/m2 on twigs and is thus ten times of the dry weight on branches but three times of dry weight on twigs. A representative tree of 27 m height has an average 65,4 kg dry weight of epiphytic bryophytes, which can store 669 liters of water. 10600 kg phytomass per hectare are estimated

    ifo Investitionstest im Baugewerbe: 2001 deutlich reduzierte Investitionsbudgets - in West und Ost

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    Die vom ifo Institut bei den Unternehmen des Baugewerbes schwerpunktmäßig noch im letzten Jahr durchgeführte Umfrage umfasste die realisierten Investitionen der Baubetriebe in selbstgenutzte Ausrüstungen und Bauten im Jahr 1999, vorläufige Zahlen zur Investitionstätigkeit im Jahr 2000 und Einschätzungen der Firmen zu ihren Investitionen im Jahr 2001 und darüber hinaus Angaben zur Struktur bzw. Zielsetzung der Investitionen. Für die Bauwirtschaft war 2000 ein Jahr enttäuschter Hoffnungen: Die Produktion des deutschen Baugewerbes schrumpfte um 2½%; dabei lag sie im Westen um ½%, im Osten um real 8 % unter den Werten von 1999. Auch in diesem Jahr ist keine zufriedenstellende Entwicklung in Sicht. Für das gesamte Bauvolumen wird für 2001 ein Rückgang von 2¼% prognostiziert. Die ersten Vorausschätzungen für 2002 lassen jedoch leichten Optimismus erkennen.Bauinvestition; Deutschland; Betriebliche Investionspolitik; Alte Bundesländer; Neue Bundesländer; Bauwirtschaft

    Using Geolocated Text to Quantify Location in Real Estate Appraisal

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    Accurate real estate appraisal is essential in decision making processes of financial institutions, governments, and trending real estate platforms like Zillow. One of the most important factors of a property’s value is its location. However, creating accurate quantifications of location remains a challenge. While traditional approaches rely on Geographical Information Systems (GIS), recently unstructured data in form of images was incorporated in the appraisal process, but text data remains an untapped reservoir. Our study shows that using text data in form of geolocated Wikipedia articles can increase predictive performance over traditional GIS-based methods by 8.2% in spatial out-of-sample validation. A framework to automatically extract geographically weighted vector representations for text is established and used alongside traditional structural housing features to make predictions and to uncover local patterns on sale price for real estate transactions between 2015 and 2020 in Allegheny County, Pennsylvania

    MRI-based quantification of adipose tissue distribution in healthy adult cats during body weight gain

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    The incidence of obesity in pet population increased over the last decades. Cats have been suggested as model for human obesity because of similar co-morbidities as diabetes and dyslipidaemia. Aim of this study were to quantify the distribution of visceral and subcutaneous adipose tissue (VAT, SAT respectively) in healthy adult cats during feeding-induced body weight (BW) gain by MRI, and to correlate it to the increased hepatic fat fraction (HFF). Cats received a commercial dry food ad libitum for 40 weeks and were longitudinally scanned three times. VAT and SAT were determined from Dixon MRI data by a dedicated software solution (ATLAS, established in human and rodents). HFF was quantified from a commercially available sequence. At both individual and group level, normalized adipose tissue volumes significantly increased longitudinally, with median VAT/SAT ratio always &lt; 1. With increased BW, more than proportional increased total adipose tissue was observed together with more than proportional increased HFF. HFF is disproportionately high in overweight cats compared to SAT and VAT accumulation in the 40 weeks observation period. Quantitative unbiased MRI examination of different body fat components is useful in longitudinal monitoring of obesity in cats

    Membrane Interaction of Ibuprofen with Cholesterol-Containing Lipid Membranes

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    Deciphering the membrane interaction of drug molecules is important for improving drug delivery, cellular uptake, and the understanding of side effects of a given drug molecule. For the anti-inflammatory drug ibuprofen, several studies reported contradictory results regarding the impact of ibuprofen on cholesterol-containing lipid membranes. Here, we investigated membrane localization and orientation as well as the influence of ibuprofen on membrane properties in POPC/cholesterol bilayers using solid-state NMR spectroscopy and other biophysical assays. The presence of ibuprofen disturbs the molecular order of phospholipids as shown by alterations of the 2H and 31P-NMR spectra of the lipids, but does not lead to an increased membrane permeability or changes of the phase state of the bilayer. 1H MAS NOESY NMR results demonstrate that ibuprofen adopts a mean position in the upper chain/glycerol region of the POPC membrane, oriented with its polar carbonyl group towards the aqueous phase. This membrane position is only marginally altered in the presence of cholesterol. A previously reported result that ibuprofen is expelled from the membrane interface in cholesterol-containing DMPC bilayers could not be confirmed.Deutsche ForschungsgemeinschaftPeer Reviewe
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