4,217 research outputs found
Sedimentology and Mineralogy of Upper Proterozoic Playa-Lake Deposits in the Damara Orogen
No full textHome Intracontinental Fold Belts
Conference paper
Sedimentology and Mineralogy of Upper Proterozoic Playa-Lake Deposits in the Damara Orogen
H.-J. Behr, H. Ahrendt, H. Martin, H. Porada, J. Röhrs & K. Weber
Conference paper
264 Accesses
15 Citations
Abstract
A thick Proterozoic meta-playa sequence (Duruchaus Formation) is developed at the southern margin of the Damara Orogen. The meta-playa sediments exhibit a characteristic lithology and contain Palaeo-evaporitic minerals.
After hot nappes of metamorphic rocks had been thrust from the Damara Orogen onto the playa sequence, a mobilisation of evaporitic carbonate layers and a hydrothermal-metasomatic metamorphism took place. The deformation along the southern margin of the Damara Orogen is largely controlled by the diapiric activity of the mobilised evaporites.
The playa-sediments of the Duruchaus Formation correspond to similar rift deposits in other parts of Gondwana which all appear to be related to a phase of world-wide Proterozoic crustal stretching.
Stratiform copper deposits and specific hydrothermal mineral concentrations are related to the playa environment and the metamorphism of the playa sediments
Misleading and reliable markers to differentiate between primate testis-derived multipotent stromal cells and spermatogonia in culture
No full textGeologische Specialkarte von Preussen und den Thüringischen Staaten / 1947 Benkheim
No full textgeognost. und agronom. bearbeitet durch J. Behr, G. Fliegel und F. KaunhowenIndirektes handschriftliches Exlibris: "1912, 466", das ist K. geolog. Landesanstalt Berlin http://doi.org/10.24439/ethz-a-000006624 Exemplar der ETH-BI
Geologische Specialkarte von Preussen und den Thüringischen Staaten / 1953 Kerschken
No full textgeognost. und agronom. bearbeitet durch J. Behr u. H. Hess v. WichdorffIndirektes handschriftliches Exlibris: "1912, 466", das ist K. geolog. Landesanstalt Berlin http://doi.org/10.24439/ethz-a-000006624 Exemplar der ETH-BI
Germ cell dynamics in the testis of the postnatal common marmoset monkey (Callithrix jacchus)
No full textThe seminiferous epithelium in the nonhuman primate Callithrix jacchus is similarly organized to man. This monkey has therefore been used as a preclinical model for spermatogenesis and testicular stem cell physiology. However, little is known about the developmental dynamics of germ cells in the postnatal primate testis. In this study, we analyzed testes of newborn, 8-week-old, and adult marmosets employing immunohistochemistry using pluripotent stem cell and germ cell markers DDX4 (VASA), POU5F1 (OCT3/4), and TFAP2C (AP-2γ). Stereological and morphometric techniques were applied for quantitative analysis of germ cell populations and testicular histological changes. Quantitative RT-PCR (qRT-PCR) of testicular mRNA was applied using 16 marker genes establishing the corresponding profiles during postnatal testicular development. Testis size increased during the first 8 weeks of life with the main driver being longitudinal outgrowth of seminiferous cords. The number of DDX4-positive cells per testis doubled between birth and 8 weeks of age whereas TFAP2C- and POU5F1-positive cells remained unchanged. This increase in DDX4-expressing cells indicates dynamic growth of the differentiated A-spermatogonial population. The presence of cells expressing POU5F1 and TFAP2C after 8 weeks reveals the persistence of less differentiated germ cells. The mRNA and protein profiles determined by qRT-PCR and western blot in newborn, 8-week-old, and adult marmosets corroborated the immunohistochemical findings. In conclusion, we demonstrated the presence of distinct spermatogonial subpopulations in the primate testis exhibiting different dynamics during early testicular development. Our study demonstrates the suitability of the marmoset testis as a model for human testicular development.</jats:p
Durch die Sprachbrille – Etische und emische Forschungsperspektiven nach der Migration
No full textNatarajan R. Durch die Sprachbrille – Etische und emische Forschungsperspektiven nach der Migration. In: Behr J, Conrad F, Kornmesser S, Tschernig K, eds. Schnittstellen der Germanistik. Festschrift für Hans Bickes. Berlin: Peter Lang ; 2020: 261–284
Silurian-Devonian and Jurassic Thermal Events in the Or dos Basin, China: Indications from K-Ar Dating on Illites
No full textIn the Ordos basin, two distinct thermal events of different ages have been identified for the first time by means of K–Ar dating combined with illite crystallinity analysis. For the Late Triassic and Late Permian samples, the K–Ar ages of the < 0.2 µm fractions (159-173 Ma) refleet an unitization age related to the Yanshanian movement and indicate a short thermal event in the Middle Jurassic; the K–Ar ages of the < 2 µm fractions (210-308 Ma) are interpreted as mixed ages of detrital material and authigenic illites. The K–Ar ages of both < 0.2 µm and < 2 µm fractions of a Middle Cambrian sample (368 Ma and 419 Ma) correspond to the ages of the metamorphism and earliest granite intrusion in the northern Caledonian Qinling fold zone (380-420 Ma) and show a thermal event during Silurian–Devonian time
Enhanced Propagation of Epileptiform Activity Through the Kindled Dentate Gyrus
No full text Behr, J., K. J. Lyson, and I. Mody. Enhanced propagation of epileptiform activity through the kindled dentate gyrus. J. Neurophysiol. 79: 1726–1732, 1998. Extracellular recordings were performed in combined hippocampal-entorhinal cortex (HC-EC) slices obtained from control and commissural kindled rats to investigate the propagation of epileptiform activity from the entorhinal cortex (EC) to the hippocampus (HC) after chronic epilepsy. Lowering extracellular Mg2+ concentration in control slices induced epileptiform activity consisting of spontaneous epileptiform bursts in area CA3 and of electrographic seizures in the EC. In contrast, the CA3 region of HC-EC slices obtained from kindled rats displayed significantly longer lasting epileptiform bursts and electrographic seizures. The electrographic seizures that were absent in controls propagated from the EC because disconnecting the HC from the EC stopped their occurrence in the CA3, whereas epileptiform bursts persisted with an unaltered pattern and frequency. Thus the area CA3 is affected by kindling and contributes to the spread of epileptiform activity within the EC-HC complex. We developed a method to induce focal epileptiform activity in the EC by locally perfusing the γ-aminobutyric acid-A (GABA) antagonist bicuculline (50 mM) in 10 mM KCl containing artificial cerebrospinal fluid. This method enabled us to investigate the propagation of epileptiform discharges from the disinhibited EC to the DG without affecting the DG with the epileptogenic medium. We show here that kindling facilitates the propagation of epileptiform activity through the DG. These data are consistent with the normal function of the DG as a filter limiting the spread of epileptiform activity within the HC-EC complex. This gating mechanism breaks down after chronic epilepsy induced by kindling. </jats:p
Die deutschen Säculardichtungen an der Wende des 18. und 19. Jahrhunderts / hrsg. von August Sauer
No full textDIE DEUTSCHEN SÄCULARDICHTUNGEN AN DER WENDE DES 18. UND 19. JAHRHUNDERTS / HRSG. VON AUGUST SAUER
Die deutschen Säculardichtungen an der Wende des 18. und 19. Jahrhunderts / hrsg. von August Sauer (1)
Cover (1)
Titelseite (3)
Widmung (4)
Vorbemerkung (5)
Inhalt (10)
Einleitung (16)
I. Das Carmen saeculare von Horaz in drei dt. Übersetzungen (88)
II. Lyrisches. (92)
Gabriele von Baumberg - Karl Theodor Gutjahr (93)
Gerhard Anton von Halem - Johann August Kunze (119)
Johann Kaspar Lavater - W. G. R. Graf Purgstall (145)
Karl Georg von Raumer - Friedrich von Schiller (168)
Friedrich Schlegel - Franz von Sonnenberg (185)
A. Cornelius Stockmann - Anonym (205)
III. Epigrammatisches (235)
IV. Theaterprologe und -Epiloge (239)
V. Dramatisches (243)
K. Fr. Benkowitz - J. W. von Goethe (244)
J. G. von Herder - A. W. Schlegel (257)
Anonym (277)
VI. Geistliche Lieder und Gebete (293)
G. L. Brückner - Anonym (294)
VII. Satirisches und Humoristisches (307)
J. D. Falk - J. Chr. Gretschel (308)
Th. Hell (K. G. Th. Winkler) - Anonym (325)
Nachtrag (358)
Anmerkungen I. - II. (365)
Anmerkungen III. - V. (385)
Anmerkungen VI. - VII. (393)
Register (400
A New Spin on the Problem of Horizontal-Branch Gaps: Stellar Rotation along the Blue Horizontal Branch of Globular Cluster M13
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