8,619 research outputs found
»Failed« Migratory Adventures?
The effects of the intra-African and European deportation regimes brought about since the European Union's externalization of its migration and development policy by transferring it to countries of sub-Saharan Africa remain largely understudied - especially their effects on people's everyday life after forced returns. Based on extensive field research, Susanne U. Schultz's book analyses the supposedly "failed" migration of Malian men, the social situations in which they find themselves following deportation, and the implications of their "failure" for their social environment and broader society. This important ethnographic study creates empirical knowledge on key issues in migration research, policy, and practice in the context of a charged debate
"Failed" Migratory Adventures? Malian Men Facing Conditions Post Deportation in Southern Mali
The effects of the intra-African and European deportation regimes brought about since the European Union's externalization of its migration and development policy by transferring it to countries of sub-Saharan Africa remain largely understudied - especially their effects on people's everyday life after forced returns. Based on extensive field research, this book analyses the supposedly "failed" migration of Malian men, the social situations in which they find themselves following deportation, and the implications of their "failure" for their social environment and broader society. This important ethnographic study creates empirical knowledge on key issues in migration research, policy, and practice in the context of a charged debate
Synthesis of Plastoquinone-9, α-Tocopherol and Phylloquinone (Vitamine K1) and its integration in chloroplast carbon metabolism of higher plants
»Failed« Migratory Adventures?
The effects of the intra-African and European deportation regimes brought about since the European Union's externalization of its migration and development policy by transferring it to countries of sub-Saharan Africa remain largely understudied - especially their effects on people's everyday life after forced returns. Based on extensive field research, Susanne U. Schultz's book analyses the supposedly "failed" migration of Malian men, the social situations in which they find themselves following deportation, and the implications of their "failure" for their social environment and broader society. This important ethnographic study creates empirical knowledge on key issues in migration research, policy, and practice in the context of a charged debate
Measurements of greenhouse gases and related tracers at Bialystok tall tower station in Poland
Quasi-continuous, in-situ measurements of atmospheric CO2, O2/N2, CH4, CO, N2O, and SF6 have been performed since August 2005 at the tall tower station near Bialystok, in Eastern Poland, from five heights up to 300 m. Besides the in-situ measurements, flask samples are filled approximately weekly and measured at Max-Planck Institute for Biogeochemistry for the same species and, in addition, for H2, Ar/N2 and the stable isotopes 13C and 18O in CO2. The in-situ measurement system was built based on commercially available analysers: a LiCor 7000 for CO2, a Sable Systems "Oxzilla" FC-2 for O2, and an Agilent 6890 gas chromatograph for CH4, CO, N2O and SF6. The system was optimized to run continuously with very little maintenance and to fulfill the precision requirements of the CHIOTTO project. The O2/N2 measurements in particular required special attention in terms of technical setup and quality assurance. The evaluation of the performance after more than three years of operation gave overall satisfactory results, proving that this setup is suitable for long term remote operation with little maintenance. The precision achieved for all species is within or close to the project requirements. The comparison between the in-situ and flask sample results, used to verify the accuracy of the in-situ measurements, showed no significant difference for CO2, O2/N2, CH4 and N2O, and a very small difference for SF6. The same comparison however revealed a statistically significant difference for CO, of about 6.5 ppb, for which the cause could not be fully explained. From more than three years of data, the main features at Bialystok have been characterized in terms of variability, trends, and seasonal and diurnal variations. CO2 and O2/N2 show large short term variability, and large diurnal signals during the warm seasons, which attenuate with the increase of sampling height. The trends calculated from this dataset, over the period August 2005 to December 2008, are 2.02±0.46 ppm/year for CO2 and -23.2±2.5 per meg/year for O2/N2. CH4, CO and N2O show also higher variability at the lower sampling levels, which in the case of CO is strongly seasonal. Diurnal variations in CH4, CO and N2O mole fractions can be observed during the warm season, due to the periodicity of vertical mixing combined with the diurnal cycle of anthropogenic emissions. We calculated increase rates of 10.1±4.4 ppb/year for CH4, (-8.3)±5.3 ppb/year for CO and 0.67±0.08 ppb/year for N2O. SF6 shows only few events, and generally no vertical gradients, which suggests that there are no significant local sources. A weak SF6 seasonal cycle has been detected, which most probably is due to the seasonality of atmospheric circulation. SF6 increased during the time of our measurement at an average rate of 0.29±0.01 ppt/year
In-situ measurements of oxygen, carbon monoxide and greenhouse gases from Ochsenkopf tall tower in Germany
We present 2.5 years (from June 2006 to December 2008) of in-situ measurements of CO2, O2, CH4, CO, N2O and SF6 mixing ratios sampled from 23, 90 and 163m above ground on the Ochsenkopf tower in the Fichtelgebirge range, Germany (50?0104900 N, 11?4803000 E, 1022ma.s.l.). In addition to the in-situ measurements, flask samples are taken at Ochsenkopf at approximately weekly intervals and are subsequently analysed for the mixing ratios of the same species, as well as H2, and the stable isotopes, ?13C, ?18O in CO2. The in-situ measurements of CO2 and O2 from 23m show substantial diurnal variations that are modulated by biospheric fluxes, combustion of fossil fuels, and by diurnal changes in the planetary boundary layer height. Measurements from 163m exhibit only very weak diurnal variability, as this height (1185ma.s.l.) is generally above the nocturnal boundary layer. CH4, CO, N2O and SF6 show little diurnal variation even at 23m owing to the absence of any significant diurnal change in the fluxes and the absence of any strong local sources or sinks. From the in-situ record, the seasonal cycles of the gas species have been characterized and the multi-annual trends determined. Because the record is short, the calculation of the trend is sensitive to inter-annual variations in the amplitudes of the seasonal cycles. However, for CH4 a significant change in the growth-rate was detected for 2006.5–2008.5 as compared with the global mean from 1999 to 2006 and is consistent with other recent observations of a renewed increasing global growth rate in CH4 since the beginning of 2007
Results from the tall tower measurement station for atmospheric greenhouse gases at Białystok, Poland
High Rate Performance of Drift Tubes
This article describes calculations and measurements of space charge effects
due to high rate irradiation in high resolution drift tubes. Two main items are
studied: the reduction of the gas gain and changes of the drift time. Whereas
the gain reduction is similar for all gases and unavoidable, the drift time
changes depend on the kind of gas that is used. The loss in resolution due to
high particle rate can be minimized with a suitable gas. This behaviour is
calculable, allowing predictions for new gas mixtures.Comment: 20 pages, submitted to Nuclear Instruments and Methods
Supersymmetric geometries of IIA supergravity I
IIA supergravity backgrounds preserving one supersymmetry locally admit four
types of Killing spinors distinguished by the orbits of on the
space of spinors. We solve the Killing spinor equations of IIA supergravity
with and without cosmological constant for Killing spinors representing two of
these orbits, with isotropy groups and .
In both cases, we identify the geometry of spacetime and express the fluxes in
terms of the geometry. We find that the geometric constraints of backgrounds
with a invariant Killing spinor are identical to
those found for heterotic backgrounds preserving one supersymmetry.Comment: 21 page
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