Technische Möglichkeiten und Akzeptanz mobiler Anwendungen

Mobile data communication applications, referred to in this paper as mobile applications, were one of the technological innovation and investment targets in recent years. From the past it became obvious that mono-disciplinary approaches to investigate mobile applications have shortcomings when it comes to successful innovation and investment decisions as interdependencies are insufficiently addressed. The paper therefore aims at structuring the scientific contributions of computer science, business economics and sociology in the context of mobile applications to approximate a holistic understanding comprising technological feasibility, economic opportunities and human needs.     

Determination ofN-nitrosodiethanolamine in cosmetics and in alkanolamines: results of collaborative studies

Summary Results of collaborative studies on methods for determination ofN-Nitrosodiethanolamine (NDELA), in cosmetics and in alkanolamines are reported. Participants from eleven laboratories in each study examined two freshly prepared model cosmetics, one emulsion and one shower gel and also one sample of triethanolamine. Samples were analyzed unspiked and after fortification with 50 g/kg NDELA. Distribution of unspiked and spiked samples and amounts of NDELA added were not known to the participants. In spiked samples overall mean values (±standard deviation) found for NDELA were 50 ± 9 gg/kg for the emulsion, 53 ± 8 gg/kg for the shower gel and 47 ± 10 g/kg for triethanolamine. With few exceptions, NDELA was not found in unspiked samples at concentrations exceeding the determination limit (10 gg/kg).

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Ergebnisse von Ringversuchen zur Bestimmung vonN-Nitrosodiethanolamin in Cosmetica und in Alkanolaminen

Zusammenfassung Ergebnisse von Ringversuchen zur Bestimmung vonN-Nitrosodiethanolamin (NDELA) in kosmetischen Mitteln and in Alkanolaminen werden beschrieben. Teilnehmer aus jeweils elf Laboratorien analysierten zwei kosmetische Mittel, die für diese Studie frisch hergestellt wurden, eine Emulsion und ein Duschbad Bowie eine Probe Triethanolamin. Die Proben wurden undotiert Bowie nach Zusatz von jeweils 50 g/kg NDELA untersucht, wobei die Verteilung und Höhe der Dotierung den Teilnehmern nicht bekannt wares. Die Gesamtmittelwerte betrugen für die dotierte Emulsion 50 g/kg NDELA±9 g/kg SD (Standardabweichung), für das dotierte Duschbad 53 g/kg NDELA±8 g/kg SD and fur das dotierte Triethanolamin 47 g/kg NDELA ± 10 g/kg SD. Mit wenigen Ausnahmen wurden in den undotierten Proben keine NDELA-Gehalte gefunden, die die Bestimmungsgrenze von 10 g/kg überschritten.

     

A method for the determination of N-nitrosoalkanolamines in cosmetics

Summary A method für the determination of N-nitrosoalkanolamines in cosmetics and toiletries is described. The ingredients used in their manufacture N-nitroso-bis-(2-hydroxyethyl)amine (N-nitrosodiethanolamine, NDELA) and N-nitroso-bis-(2-hydroxypropyl)amine (NBHPA) are almost exclusively the contaminants. The method has therefore been modified for their determination. N-Nitroso-(2-hydroxyethyl)-(2-hydroxypropyl)amine is used as the internal standard. After dilution with water, the cosmetic is adsorbed onto a kieselguhr column and extracted with n-butanol. The extract is brought to dryness, re-dissolved in chloroform/acetone (5 + 1) and transferred to a silica gel column. The column is washed and eluted with acetone. The eluate is dried and the residue is treated with N-methyl-N-trimethylsilyl-heptafluorobutyramide. Trimethylsilyl (TMS)derivatives of N-nitrosoalkanolamines are determined by gas-chromatography with a thermal energy analyzer (TEA). Recovery of the internal standard is 95% and the determination limit is 5 g/kg, Repeated analyses of a foam bath, spiked with 30 g/kg NDELA, gave an average content of 32 g/kg NDELA (variation coefficient 8.8%;n=10). In order to avoid artefact formation during the clean-up process, kieselguhr containing 50% sodium ascorbate has to be used when cosmetics containing free dialkanolamines are analyzed.

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Ein Bestimmungsverfahren für N-Nitrosoalkanolamine in kosmetischen Mitteln

Zusammenfassung Ein Verfahren zur Bestimmung von N-Nitrosoalkanolaminen in kosmetischen Mitteln wird beschrieben. Da die technisch eingesetzten Grundstoffe praktisch ausschließlich zu Kontamination mit N-Nitroso-bis-(2-hydroxyethyl)amin (N-Nitrosodiethanolamin, NDELA) und N-Nitroso-bis-(2-hydroxypropyl)amin (NBHPA) führen, ist das Verfahren auf die Erfassung dieser Nitrosamine optimiert. Die mit Wasser verdünnte Probe wird nach Aufgabe auf eine Kieselgursäule mit n-Butanol extrahiert. Das Lösungsmittel wird abgedampft, der Rückstand in Chloroform/Aceton (5 + 1) aufgenommen und auf eine Kieselgelsäule gegeben. Nach Waschen wird mit Aceton eluiert. Das Eluat wird von Aceton befreit, der Rückstand trimethylsilyliert. Trimethylsilyl (TMS)-Derivate der N-Nitrosoalkanolamine werden gaschromatographisch mit dem Thermal Energy Analyzer (TEA) erfaßt. Die Wiederfindung des internen Standards N-Nitroso-(2-hydroxyethyl)-(2-hydroxypropyl)amin (NBHPA) liegt bei 95%, die Bestimmungsgrenze für NDELA bei 5 g/kg. Wiederholte Analysen eines mit 30 g/kg dotierten Schaumbades ergaben einen mittleren Gehalt von 32 g/kg NDELA (Variationskoeffizient = 8,8%,n=10). Zur Vermeidung der Artefaktbildung während der Aufarbeitung muß bei Analysen von kosmetischen Mitteln mit Gehalt an freien Dialkanolaminen Kieselgur mit Zusatz von 50% Natriumascorbat zur Festphasenextraktion verwendet werden.

     

Validation of the collection 5 MODIS FPAR product in a heterogeneous agricultural landscape in arid Uzbekistan using multitemporal RapidEye imagery

The fraction of photosynthetically active radiation (FPAR) absorbed by a vegetation canopy is an important variable for global vegetation modelling and is operationally available from data of the Terra Moderate Resolution Imaging Spectroradiometer (MODIS) satellite sensor starting from the year 2000. Product validation is ongoing and important for constant product improvement, but few studies have investigated the specific accuracy of MODIS FPAR using in situ measurements and none have focused on agricultural areas. This study therefore presents a validation of the collection 5 MODIS FPAR product in a heterogeneous agricultural landscape in western Uzbekistan. High-resolution FPAR maps were compiled via linear regression between in situ FPAR measurements and the RapidEye normalized difference vegetation index (NDVI) for the 2009 season. The data were aggregated to the MODIS scale for comparison. Data on the percentage cover of agricultural crops per MODIS pixel allowed investigation of the impact of spatial heterogeneity on MODIS FPAR accuracy. Overall, the collection 5 MODIS FPAR overestimated RapidEye FPAR between approximately 6% and 15%. MODIS quality flags, the underlying biome classification and spatial heterogeneity were investigated as potential sources of error. MODIS data quality was very good in all cases. A comparison of the MODIS land-cover product with high-resolution land-use classification revealed a significant misclassification by MODIS. Yet, we found that the overestimation of MODIS FPAR is independent of classification accuracy. The results indicate that the amount of background information, present even in the most homogeneous pixels (～70% crop cover), is most likely the reason for the overestimation. The behaviour of pure pixels could not be investigated due to a lack of appropriate pixels.     

Elevated social anxiety among early maturing girls.

Adolescence is a key period in terms of the development of anxiety psychopathology. An emerging literature suggests that early pubertal maturation is associated with enhanced vulnerability for anxiety symptomatology, although few studies have examined this association with regard to social anxiety. Accordingly, the current study was designed to further elucidate the relation between pubertal timing and social anxiety, with a focus on clarifying the role of gender. Participants were 138 adolescents (ages 12–17 years) recruited from the general community. Level of social anxiety was examined as a function of gender and within-sample pubertal timing. As expected, early maturing girls evidenced significantly higher social anxiety, compared with on-time girls and early maturing boys, and no other differences were found as a function of gender or developmental timing. Findings and future directions are discussed in terms of forwarding developmentally sensitive models of social anxiety etiology and prevention. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Impact of ozonation on ecotoxicity and endocrine activity of tertiary treated wastewater effluent

Tertiary wastewater treatment plant effluent before and after ozonation (0.6-1.1 g O₃/g DOC) was tested for aquatic ecotoxicity in a battery of standardised microbioassays with green algae, daphnids, and zebrafish eggs. In addition, unconjugated estrogen and 17β-hydroxyandrogen immunoreactive substances were quantified by means of enzyme immunoassays, and endocrine effects were analysed in a 21-day fish screening assay with adult male and female medaka (Oryzias latipes). Ozonation decreased estrogen-immunoreactivity by 97.7 ± 1.2% and, to a lesser extent, androgen-immunoreactivity by 56.3 ± 16.5%. None of the short-term exposure ecotoxicity tests revealed any adverse effects of the tertiary effluent, neither before nor after the ozonation step. Similarly in the fish screening assay, reproductive fitness parameters showed no effects attributed to micropollutants, and no detrimental effects of the effluents were observed. Based on the presented screening, ozonation effectively reduced steroid hormone levels in the wastewater treatment plant effluent without increasing the effluent's ecotoxicity.     

Einflüsse von Mo,V, Nb,Ti, Zr und deren Karbiden auf die Korrosion und Wasserstoffaufnahme des Eisens in Schwefelsäure

Effects of Mo, V, Nb, Ti, Zr and their carbides on the corrosion and hydrogen uptake of iron in sulphuric acid The effects of Mo, V, Nb, Ti, Zr and their carbides on the corrosion and hydrogen uptake of iron in 1 M H₂SO₄/N₂/25°C were investigated by electrochemical and surface analytical methods using binary and ternary Fe-Me alloys with about 0.2 at.-%Me. Due to the experimental conditions, no protective surface layers formed. The transition metals were enriched at the iron surface only as a carbide or oxicarbide. Mo or Zr were not markedly enriched. The corrosion current density and the hydrogen activity were decreased only by Mo or Zr. Hydrogen permeation measurements were analysed in terms of the trapping theory. The average binding energy of shallow traps for hydrogen increases with increasing atomic radius of the substituted alloying elements in the order V, Mo, Ti, Nb and Zr. Correspondingly, the hydrogen diffusion coefficient (after saturation of the deep traps) decreases and the hydrogen solubility increases. The steadystate hydrogen permeation rate remains almost unaffected. The total hydrogen content is determined by the density of deep traps and thus mostly independent of the external hydrogen activity. The trapping effect of iron is strongly increased by dissolved Zr or Nb or in the presence of fine dispersed carbides as VC_x. The effect of coarse carbide particles at a lower density is small.     

Using earth observation-based dry season NDVI trends for assessment of changes in tree cover in the Sahel

The co-existence of trees and grasses is a defining feature of savannah ecosystems and landscapes. During recent decades, the combined effect of climate change and increased demographic pressure has led to complex vegetation changes in these ecosystems. A number of recent Earth observation (EO)-based studies reported positive changes in biological productivity in the Sahelian region in relation to increased precipitation, triggering an increased amount of herbaceous vegetation during the rainy season. However, this ‘greening of the Sahel’ may mask changes in the tree–grass composition, with a potential reduction in tree cover having important implications for the Sahelian population. Large-scale EO-based evaluation of changes in Sahelian tree cover is assessed by analysing long-term trends in dry season minimum normalized difference vegetation index (NDVI_min) derived from three different satellite sensors: Système Pour l’Observation de la Terre (SPOT)-VEGETATION (VGT), Terra Moderate Resolution Imaging Spectroradiometer (MODIS), and the Advanced Very High Resolution Radiometer (AVHRR) Global Inventory Modeling and Mapping Studies (GIMMS) dataset. To evaluate the reliability of using NDVI_min as a proxy for tree cover in the Sahel, two factors that could potentially influence dry season NDVI_min estimates were analysed: the total biomass accumulated during the preceding growing season and the percentage of burned area observed during the dry season. Time series of dry season NDVI_min derived from low-resolution satellite time series were found to be uncorrelated to dry grass residues from the preceding growing season and to seasonal fire frequency and timing over most of the Sahel (88%), suggesting that NDVI_min can serve as a proxy for assessing changes in tree cover. Good agreement (R² = 0.79) between significant NDVI_min trends (p < 0.05) derived from VGT and MODIS was found. Significant positive trends in NDVI_min were registered by both MODIS and VGT dry season NDVI_min time series over the Western Sahel, whereas trends based on GIMMS data were negative for the greater part of the Sahel. EO-based trends were generally not confirmed at the local scale based on selected study cases, partly caused by a temporal mismatch between data sets (i.e. different periods of analysis). Analysis of desert area NDVI_min trends indicates less stable values for VGT and GIMMS data as compared with MODIS. This suggests that trends in dry season NDVI_min derived from VGT and GIMMS should be used with caution as an indicator for changes in tree cover, whereas the MODIS data stream shows a better potential for tree-cover change analysis in the Sahel.