Der Weg der Bünde: transethnische Forschung im Cross River-Gebiet

'In den letzten Jahrzehnten sind vermehrt ethnologische Studien ins Zentrum der Aufmerksamkeit gerückt, die nicht auf einem Zentrum-Peripherie-Modell oder auf einer ethnischen Gruppe als Untersuchungseinheit basieren, sondern zunehmend mobil und multilokal sind. Gleichzeitig haben Vorgänge der Verbreitung und der Mobilität von Menschen, Dingen, Ideen, Institutionen etc. an Bedeutung gewonnen. Dieser veränderte Fokus erfordert eine Erweiterung der ethnografischen Methoden. Dieser Aufsatz stellt einige der methodischen Implikationen eines Forschungsprojekts vor, dessen Ziel es war, die Verbreitungsgeschichten von Bünden im Cross River-Gebiet von Kamerun und Nigeria nachzuzeichnen. Die meisten Bünde werden dort als immaterielles Eigentum gehandelt und verbreiten sich durch Kauf und Verkauf von Dorf zu Dorf, ungeachtet sprachlicher Grenzen. Einige der Bünde schaffen auf diese Weise neue, imaginierte Gemeinschaften von Besitzern derselben Bünde. Die Synthese der Einzelgeschichten in den untersuchten Ortschaften ermöglichte die Rekonstruktion einer so entstandenen Bundlandschaft. Die Studie ging somit nicht von einem lokalen Standpunkt aus, sondern vom Untersuchungsgegenstand im Prozess seiner Verbreitung durch ihre jeweiligen Besitzer. Der Vergleich der Orte legte zudem eine enge Verknüpfung der ökonomischen und politischen Situation einer Dorfgemeinschaft mit ihrer Bereitschaft zur Erinnerung und der Tradierung ihrer spezifischen Geschichte nahe.' (Autorenreferat)'In recent years, ethnographic studies that were based on a centre-periphery model or on one ethnic group have largely been replaced by studies on the mobility of people, things, ideas, institutions etc. Multilocal research also calls for an elaboration of research methods. This paper presents some methodological implications of a research project which aimed at reconstructing the specific histories of the dissemination of associations in the Cross River region of Cameroon and Nigeria. The owners of the associations regard the latter as their intellectual property and trade them to interested parties. In this way, associations spread widely and some of them have created new (imagined) communities among owners of the same association. The landscape of associations represents the synthesis of local histories. The study's starting point was not specific localities but the associations and the dissemination process under the control of their owners. A comparison of the data collected in the localities under study points to a relation between a community's economic and political situation and its capacity to remember its history.' (author's abstract

Introduction: Young people working for better lives in West and Central Africa

After more than a decade of emphasizing African children’s and youth’s agencies, possibilities and creativities in more or less challenging social, political and economic environments (see Bordonaro & Carvalho, 2010; Christiansen, Utas, & Vigh, 2006; Honwana & de Boeck, 2005; Martin, Ungruhe, & Häberlein, 2016; Spittler & Bourdillon, 2012), other recent studies increasingly highlight the young people’s powerlessness, bleak presents and uncertain futures. Doing so, the image of an enduring soc..

An improved synthesis and some reactions of diethyl 4-oxo-4H-pyran-2,5- dicarboxylate

The reaction of ethyl 2-(dimethylamino)methylene-3-oxobutanoate with diethyl oxalate in the presence of sodium hydride in THF gave diethyl 4-oxo-4H-pyran-2,5-dicarboxylate, from which 4-oxo-4H-pyran-2,5-dicarboxylic and 4-oxo-1-phenyl-1,4-dihydropyridine-2,5-dicarboxylic acids and their derivatives were obtained in good yields. © 2013 Elsevier Ltd. All rights reserved

Synthesis of benzopyranopyrrolidines via 1,3-dipolar cycloaddition of nonstabilized azomethine ylides with 3-substituted coumarins

A three-component reaction of 3-substituted coumarins with N-alkyl-α-amino acids and aldehydes gave 1-benzopyrano[3,4-c]pyrrolidines as a result of a 1,3-dipolar cycloaddition of an intermediate nonstabilized azomethine ylide at the double bond of the coumarin system in moderate to good yields. In most cases, high regio- and stereo-selectivity of the [3+2] cycloaddition was observed. © 2013 Elsevier Ltd. All rights reserved

Introduction: Young people working for better lives in West and Central Africa

After more than a decade of emphasizing African children’s and youth’s agencies, possibilities and creativities in more or less challenging social, political and economic environments (see Bordonaro & Carvalho, 2010; Christiansen, Utas, & Vigh, 2006; Honwana & de Boeck, 2005; Martin, Ungruhe, & Häberlein, 2016; Spittler & Bourdillon, 2012), other recent studies increasingly highlight the young people’s powerlessness, bleak presents and uncertain futures. Doing so, the image of an enduring soc..

A new airborne broadband radiometer system and an efficient method to correct thermal offsets

The instrumentation of the High Altitude and Long Range (HALO) research aircraft is extended by the new Broadband AirCrAft RaDiometer Instrumentation (BACARDI) to quantify the radiative energy budget. Two sets of pyranometers and pyrgeometers are mounted to measure upward and downward solar (0.3&ndash;3 &mu;m) and thermal-infrared (3&ndash;100 &mu;m) irradiances. The radiometers are installed in a passively ventilated fairing to reduce the effects of the dynamic environment, e.g., fast changes of altitude and temperature. The remaining thermal effects range up to 20 W m-2 for the pyranometers and 10 W m-2 for the pyrgeometers; they are corrected using an new efficient method that is introduced in this paper. Using data collected by BACARDI during a night flight, the thermal offsets are parameterized by the rate of change of the radiometer sensor temperatures. Applying the sensor temperatures instead of ambient air temperature for the parameterization provides a linear correction function (200&ndash;600 W m-2 K-1 s), that depends on the mounting position of the radiometer on HALO. Furthermore, BACARDI measurements from the EUREC4A (Elucidating the role of clouds-circulation coupling in climate) field campaign are analyzed to characterize the performance of the radiometers and to evaluate all corrections applied in the data processing. Vertical profiles of irradiance measurements up to 10 km altitude show that the thermal offset correction limits the bias due to temperature changes to values below 10 W m-2. Measurements with BACARDI during horizontal, circular flight patterns in cloud-free conditions demonstrate that the common geometric attitude correction of the solar downward irradiance provides reliable measurements in this typical flight sections of EUREC4A, even without active stabilization of the radiometer.</p

VELOX - a new thermal infrared imager for airborne remote sensing of cloud and surface properties

The new airborne thermal infrared (TIR) imager VELOX (Video airbornE Longwave Observations within siX channels) is introduced. VELOX is a commercially available TIR camera system that has been adapted extensively for atmospheric applications, which are introduced in this paper. The system covers six spectral bands with centre wavelengths between 7.7 and 12 µm. Currently, VELOX is installed on board the German High Altitude and Long Range Research Aircraft (HALO) to observe cloud and surface properties. It provides observations of two-dimensional (2D) fields of upward terrestrial spectral radiance with a horizontal resolution of approximately 10 m×10 m at a target distance of 10 km. Atmospheric temperature values are rather low compared to the originally intended commercial applications of VELOX and range close to the detection limit of the sensor. This challenge requires additional calibration efforts to enable atmospheric applications of VELOX. Therefore, required sophisticated calibration and correction procedures, including radiometric calibrations, non-uniformity corrections, bad-pixel replacements, and window corrections, are presented. Furthermore, first observations of cloud properties acquired by VELOX during the EUREC4A (ElUcidating the RolE of Cloud-Circulation Coupling in ClimAte) campaign are discussed, including an analysis of the cloud top brightness temperature, cloud mask/fraction, and cloud top altitude data. The data reveal the potential of VELOX to resolve the cloud top temperature with a resolution of better than 0.1 K, which translates into a resolution of approximately 40 m in cloud top altitude

A tandem approach for collocated measurements of microphysical and radiative cirrus properties

Microphysical and radiation measurements were collected with the novel AIRcraft TOwed Sensor Shuttle (AIRTOSS) – Learjet tandem platform. The platform is a combination of an instrumented Learjet 35A research aircraft and an aerodynamic bird, which is detached from and retracted back to the aircraft during flight via a steel wire with a length of 4000 m. Both platforms are equipped with radiative, cloud microphysical, trace gas, and meteorological instruments. The purpose of the development of this tandem set-up is to study the inhomogeneity of cirrus as well as other stratiform clouds. Sophisticated numerical flow simulations were conducted in order to optimally integrate an axially asymmetric Cloud Combination Probe (CCP) inside AIRTOSS. The tandem platform was applied during measurements at altitudes up to 36 000 ft (10 970 m) in the framework of the AIRTOSS – Inhomogeneous Cirrus Experiment (AIRTOSS-ICE). Ten flights were performed above the North Sea and Baltic Sea to probe frontal and in situ formed cirrus, as well as anvil outflow cirrus. For one flight, cirrus microphysical and radiative properties displayed significant inhomogeneities resolved by both measurement platforms. The CCP data show that the maximum of the observed particle number size distributions shifts with decreasing altitude from 30 to 300 µm, which is typical for frontal, midlatitude cirrus. Theoretical considerations imply that cloud particle aggregation inside the studied cirrus is very unlikely. Consequently, diffusional growth was identified to be the dominant microphysical growth process. Measurements of solar downward and upward irradiances at 670 nm wavelength were conducted above, below, and in the cirrus on both the Learjet and AIRTOSS. The observed variability of the downward irradiance below the cirrus reflects the horizontal heterogeneity of the observed thin cirrus. Vertically resolved solar heating rates were derived by either using single-platform measurements at different altitudes or by making use of the collocated irradiance measurements at different altitudes of the tandem platform. Due to unavoidable biases of the measurements between the individual flight legs, the single-platform approach failed to provide a realistic solar heating rate profile, while the uncertainties of the tandem approach are reduced. Here, the solar heating rates range up to 6 K day−1 at top of the cirrus layer