Search Results - (Author, Cooperation:Böttner)

Böttner, Joachim

Unknown

202 S. : Ill., graph. Darst. + Demoversion Digitaler Unterrichtsassistent

1. Aufl., 1. Druck

9783127423518

German

Böttner, Joachim

Unknown

180 S. : Ill., graph. Darst.

1. Aufl., 1. Druck

9783127423877

German

Böttner, Joachim

Unknown

40 S. : graph. Darst.

1. Aufl.

9783127403589

German

2018-07-27

Auf der Basis einer Videografie an einer Kinderuniversität wird in dem vorliegenden Beitrag die Frage verfolgt, wie an einem außerschulischen Lernort generationale Ordnung hergestellt wird und welche Gestalt diese annimmt. Als heuristischer Rahmen dient das Modell der "Sozialisation als generationales Ordnen" (Bühler-Niederberger 2011; Bühler-Niederberger & Türkyilmaz 2014). Die Analyse der ersten Sitzungen von zwei kontrastiven Kursen an der Kinder- und Jugenduniversität zeigt erstens, wie Kinder struktursensitiv Regeln in dem unbekannten Kontext erspüren, erarbeiten und modifizieren, wie sie KomplizInnen in der Herstellung generationaler Ordnung sind. Zweitens wird die Dominanz der schulischen Ordnung und des SchülerInnenstatus für Kindheit deutlich. Die Kinder stellen "Schule" her - paradoxerweise auch in einem außerschulischen Kontext. Drittens wird im kontrastiven Vergleich der untersuchten Kurse eine Varianz dieser Ordnungen -in Bezug auf die Form des Wissens und Adressierung der Kinder- herausgearbeitet, die allerdings die Dominanz der schulischen Ordnung nicht bricht. (Autorenreferat)

Based on video data collected at a children's university we discuss how generational order is produced and shaped into different constellations. As a theoretical reference point we use the concept of "socialization as generational ordering" (Bühler-Niederberger, 2011; Bühler-Niederberger & Türkyilmaz, 2014). Analysis of the initial sessions of two different courses at this out-of-school learning facility shows three things: First, how children grasp, work out, and modify rules in such an unfamiliar context and how this makes them accomplices in the production of generational order. Second, how children paradoxically are "doing pupil" as well in this out-of-school setting, revealing the dominance of "school order". Third, by a contrastive analysis of courses, a certain variety of these ordering processes can be found. This variety concerns forms of knowledge and the ways children are addressed; however, the dominance of the "school order" is hardly challenged. (author's abstract)

Sociology & anthropology ; Soziologie, Anthropologie ; Kinderuniversität; Videografie; generationale Ordnung ; Jugendsoziologie, Soziologie der Kindheit ; Sociology of the Youth, Sociology of Childhood ; childhood ; generation ; video ; university ; pupil ; school ; learning ; child ; socialization at school ; Generation ; Universität ; Schule ; Kindheit ; Video ; schulische Sozialisation ; Kind ; Lernen ; Schüler

journal article, Zeitschriftenartikel

1089-7550

AIP Digital Archive

Physics

The results of an experimental study of photoelectrical and optical properties of molecular beam epitaxy grown Pb1−xEuxSe are presented. The data obtained are discussed with respect to band structure of the mixed crystal obtained by a linear interpolation between the relevant energy states in the binaries PbSe and EuSe.

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

The technique of H(D) atom photofragment translational spectroscopy has been applied to the photodissociation of H2S(D2S) following excitation at a number of wavelengths in its first absorption continuum. The respective bond dissociation energies were determined as D0(H–SH)=3.90±0.03 eV and D0(D–SD)=4.00±0.02 eV. The measured vibrational energy disposal in the partner ground state SH(SD) fragments and the product angular distributions support and extend the earlier results of van Veen et al. [Chem. Phys. 74, 261 (1983)], while the deduced rotational and spin–orbit state population distributions in these fragments appear to be generally consistent with the recent measurements of Weiner et al. [J. Chem. Phys. 90, 1403 (1989)]. We present a schematic adiabatic potential energy surface for the dissociative 1A‘ excited state via which it is possible to rationalize virtually all existing dynamical measurements relating to this fragmentation process.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract: Transforming growth factor-βs (TGF-βs) are amongthe most widespread and versatile cytokines. Here, we first provide a briefoverview of their molecular biology, biochemistry, and signaling. We thenreview distribution and functions of the three mammalian TGF-β isoforms,β1, β2, and β3, and their receptors in the developing and adultnervous system. Roles of TGF-βs in the regulation of radial glia,astroglia, oligodendroglia, and microglia are addressed. Finally, we reviewthe current state of knowledge concerning the roles of TGF-βs incontrolling neuronal performances, including the regulation of proliferationof neuronal precursors, survival/death decisions, and neuronaldifferentiation.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

A study of the threshold of stimulated emission for optically pumped PbSe and PbTe is presented. The influence of external parameters such as magnetic field and misfit strain on the threshold as well as the differential quantum efficiency of stimulated emission are analyzed. It is shown that effective energy gap shifts caused by the external parameters only weakly influence the threshold, whereas the main effect arises from the redistribution of the carriers in the multivalley band structure when the degeneracy of the carriers in the valleys at the L points of the Brillouin zone is lifted. A consistent qualitative theoretical explanation for the effects is given. © 1995 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Double-channel double-heterostructure (DCDH) lead chalcogenide lasers were made using a chemical etchant. The etching rate depends strongly on the europium content of the ternary compound PbxEu1−xSe. This technique allows the development of selective etching processes for advanced laser design. The DCDH lasers show low-threshold current densities of 60 A/cm2 at 20 K and suppression of lateral modes.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Infrared (IR) diode lasers have been made by growing heterostructures or graded structures of Pb1−xEuxSe. This IV-VI ternary has a small lattice variation within the IR band-gap range. Double-heterostructure lasers with PbSe active layers were operated up to T=174 K cw and 220 K pulsed mode; they reached the highest cw operation temperature reported for this type of laser in the mid IR. Their tuning range was 7.8–5.7 μm cw. Lasers with the ternary as the active layer were operated up to the shortest wavelength of 2.88 μm at 100 K cw. At present lasers made by molecular beam epitaxy of this material cover the widest wavelength region at T〉77 K around 5 μm in cw operation.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Double-Heterostructure lasers have been fabricated with an active layer of PbSe sandwiched between cladding layers of Pb1−x Srx Se. They were operated up to T=290 K (17 °C) in pulsed and T=169 K in cw mode. This is the highest operational temperature in pulsed mode reported for lead salt lasers in the mid-infrared. The emission wavelength tunes with temperature from 8.0 μm (T=20 K) to 4.4 μm (T=285 K).

Electronic Resource

1077-3118

AIP Digital Archive

Physics

IV-VI multiple-quantum-well lasers with seven wells made from molecular-beam-epitaxy grown PbSe/PbSrSe have been operated in pulsed mode up to 282 K at a wavelength of λ=4.2 μm. This is the highest midinfrared quantum well laser operation temperature observed to date. © 1995 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

We report on an enhanced thermoelectric figure of merit ZT=σS2T/λ (where σ is electrical conductivity, S is thermopower, T is absolute temperature, and λ is thermal conductivity) for PbTe/PbSe0.20Te0.80 superlattices (SLs) and PbTe doping SLs due to a reduction of the thermal conductivity λ parallel to the layer planes. Despite a small decrease of the power factors σS2 due to a reduction of σ in these superlattices, the figure of merit is higher as compared to the corresponding bulk materials and reaches maximum values in the temperature range between 400 and 570 K.© 2002 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

PbSrS/PbS double-heterostructure and multiple quantum well lasers were prepared by hot wall epitaxy, and the dependence of the properties on the cladding layer band gap and active layer thickness was investigated. Output photon energy of the double-heterostructure laser shifted to the high energy side owing to the strain between PbSrS cladding and the PbS active layers. The shift decreased by increasing the PbS active layer thickness. It was estimated that the lattice mismatch between cladding and the active layers is accommodated by the strain when the PbS active layer thickness is as thin as 0.5 μm.

Electronic Resource

1460-9568

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Bone morphogenetic proteins (BMPs) are members of the transforming growth factor β (TGF-β) superfamily that have been implicated in tissue growth and remodelling. Recent evidence suggests that several BMPs are expressed in the developing and adult brain. Specifically, we show that BMP 2 and BMP 6 are expressed in the developing midbrain floor of the rat. We studied potential neurotrophic effects of BMPs on the in vitro survival, transmitter uptake and protection against MPP+ toxicity of mesencephalic dopaminergic neurons cultured from the embryonic midbrain floor at embryonic day (E) 14. At 10 ng/ml and under serum-free conditions, most BMPs promoted the survival of dopaminergic neurons visualized by tyrosine hydroxylase immunocytochemistry during an 8-day culture period, but to varying extents (relative potencies: BMP 6 = 12 〉 2, 4, 7). BMPs 6 and 12 were as effective as fibroblast growth factor-2 (FGF-2) and glial cell line-derived neurotrophic factor, promoting survival 1.7-fold compared with controls. BMPs 9 and 11 were not effective. Dose-response curves revealed an EC50 for BMPs 2, 6 and 12 of 2 ng/ml. BMPs 2, 4, 6, 7, 9 and 12 also promoted DNA synthesis and astroglial cell differentiation, visualized by 5-bromodeoxyuridine (BrdU) incorporation and glial fibrillary acidic protein (GFAP) immunocytochemistry respectively. Suppression of cell proliferation and subsequent maturation of GFAP-positive cells by 5-fluorodeoxyuridine or aminoadipic acid abolished the neuron survival-promoting effect of BMP 2. This suggests that BMPs, like other non-TGF-β factors affecting dopaminergic neuron survival, act indirectly, probably by stimulating the synthesis and/or release of glial-derived trophic factors. BMP 6 and BMP 7 also increased the uptake of [3H]dopamine without affecting the uptake of [3H]5-hydroxytryptamine and [3H]GABA, underscoring the specificity of the trophic effect. We conclude that several BMPs share a neurotrophic capacity for dopaminergic midbrain neurons with other members of the TGF-β superfamily, but act indirectly, possibly through glial cells.

Electronic Resource

1460-9568

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Bone morphogenetic proteins (BMPs), growth and differentiation factor 5 (GDF5) and glial cell line-derived neurotrophic factor (GDNF) are members of the transforming growth factor-β superfamily that have been implicated in tissue growth and differentiation. Several BMPs are expressed in embryonic and adult brain. We show now that BMP-2, –6 and –7 and GDF5 are expressed in the embryonic rat hindbrain raphe. To start to define roles for BMPs in the regulation of serotonergic (5-HT) neuron development, we have generated serum-free cultures of 5-HT neurons isolated from the embryonic (E14) rat raphe. Addition of saturating concentrations (10 ng/mL) of BMP-6 and GDF5 augmented numbers of tryptophan hydroxylase (TpOH) -immunoreactive neurons and cells specifically taking up 5,7-dihydroxytryptamine (5,7-DHT) by about two-fold. Alterations in 5-HT neuron numbers were due to the induction of serotonergic markers rather than increased survival, as shown by the efficacy of short-term treatments. Importantly, BMP-7 selectively induced 5,7-DHT uptake without affecting TpOH immunoreactivity. BMP-6 and –7 also promoted DNA synthesis and increased numbers of cells immunoreactive for vimentin and glial fibrillary acidic protein (GFAP). Pharmacological suppression of cell proliferation or glial development abolished the induction of serotonergic markers by BMP-6 and –7, suggesting that BMPs act indirectly by stimulating synthesis or release of glial-derived serotonergic differentiation factors. Receptor bodies for the neurotrophin receptor trkB, but not trkC, abolished the BMP-mediated effects on serotonergic development, suggesting that the glia-derived factor is probably brain-derived neurotrophic factor (BDNF) or neurotrophin-4. In support of this notion, we detected increased levels of BDNF mRNA in BMP-treated cultures. Together, these data suggest both distinct and overlapping roles of several BMPs in regulating 5-HT neuron development.

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] To determine the acetone in blood, a 10-ml. oxalated sample is pipetted into a 40-ml. glass centrifuge tube fitted with a ground-glass stopper. 15 ml. of carbon disulphide is added, and the tube gently shaken for 10 min. on an automatic shaker. The tube is then centrifuged in a refrigerated ...

Electronic Resource

0022-2860

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Physics

Electronic Resource

0031-9422

Guttiferae ; Psorospermum febrifugum ; Vismieae ; cytotoxic and antitumour xanthones. ; xanthones

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Electronic Resource

0371-1951

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Physics

Electronic Resource