Anelastic Versus Fully Compressible Turbulent Rayleigh-B\'enard Convection

Numerical simulations of turbulent Rayleigh-B\'enard convection in an ideal gas, using either the anelastic approximation or the fully compressible equations, are compared. Theoretically, the anelastic approximation is expected to hold in weakly superadiabatic systems with $\epsilon = \Delta T / T_r \ll 1$, where $\Delta T$ denotes the superadiabatic temperature drop over the convective layer and $T_r$ the bottom temperature. Using direct numerical simulations, a systematic comparison of anelastic and fully compressible convection is carried out. With decreasing superadiabaticity $\epsilon$, the fully compressible results are found to converge linearly to the anelastic solution with larger density contrasts generally improving the match. We conclude that in many solar and planetary applications, where the superadiabaticity is expected to be vanishingly small, results obtained with the anelastic approximation are in fact more accurate than fully compressible computations, which typically fail to reach small $\epsilon$ for numerical reasons. On the other hand, if the astrophysical system studied contains $\epsilon\sim O(1)$ regions, such as the solar photosphere, fully compressible simulations have the advantage of capturing the full physics. Interestingly, even in weakly superadiabatic regions, like the bulk of the solar convection zone, the errors introduced by using artificially large values for $\epsilon$ for efficiency reasons remain moderate. If quantitative errors of the order of $10\%$ are acceptable in such low $\epsilon$ regions, our work suggests that fully compressible simulations can indeed be computationally more efficient than their anelastic counterparts.Comment: 24 pages, 9 figure

Mani und Aristoteles. Das sechste Kapitel der koptischen Kephalaia, Textanalyse und Interpretation. Wiesbaden, Harrassowitz, 2002, VI-368 p., bibliogr. (Göttinger Orientforschungen. IV. Reihe : Ägypten 42).

Dans son examen détaillé du contenu et de la structure du sixième chapitre des « Kephalaia » coptes qui traite du mal en soi et de ses manifestations, l’A. a réussi à éclaircir les macro- et superstructures de ce texte « obscurci » et marqué par un langage symbolique très prononcé et elle a révélé son arrière-plan mythologique, philosophique et théologique. Le travail évoque non seulement les solutions manichéennes apportées aux problèmes de l’être, de la Pérennité et du Non-être, mais il dém..

NOURUZ IN PERSEPOLIS? EINE RESIDENZ, DAS NEUJAHRSFEST UND EINE THEORIE

NOURUZ IN PERSEPOLIS? EINE RESIDENZ,DAS NEUJAHRSFEST UND EINE THEORI

Alte Geschichte in Kiel (1863-1976)

In diesem Beitrag wird die Geschichte der Alten Geschichte an der Christian-Albrechts-Universität von der Einrichtung des ersten Lehrstuhls für Alte Geschichte im Jahre 1863 bis zum Tod des letzten verstorbenen Stelleninhabers im Jahre 1976 behandelt. Von 1863 bis 1945 war dieses Fach Bestandteil des Historischen Seminars, danach, zusammen mit der Klassischen Philologie (und neuerdings auch der Klassischen Archäologie) Teil des Instituts für Klassische Altertumskunde. In dem Beitrag werden neben biographischen Informationen auch solche geboten, die über die Forschungsschwerpunkte der Stelleninhaber unterrichten und ihr Wirken in Kiel vor dem Hintergrund der allgemeinen politischen, geistesgeschichtlichen, fachdisziplinären und forschungsrelevanten Entwicklungen beschreiben. Dabei zeigt sich zum einen, dass der universitäre Standort Kiel für viele Lehrstuhlinhaber Sprungbrett für eine akademische Karriere an prestigeträchtigeren Universitäten war. Zum anderen ergaben die Nachforschungen, dass, obgleich jeder Lehrstuhlinhaber eigene Akzente in Lehre und Forschung setzte, dennoch bestimmte Forschungsschwerpunkte immer wieder verfolgt wurden: die Beschäftigung mit epigraphischen, numismatischen und papyrologischen Zeugnissen (vgl. zum Beispiel Max Leberecht Strack, Paul Leberecht Strack, Herbert Nesselhauf, Horst Braunert et al.) und der Versuch, die Kulturen Griechenlands und Roms in größere kulturelle und politische Zusammenhänge einzubetten und die Welt Eurasiens als eine vielfach vernetzte Welt zu begreifen (vgl. Alfred von Gutschmid, Hugo Prinz). Beide Ansätze zeichnen das Fach im Übrigen bis heute aus.This article deals with the history of Ancient History at Kiel University from the establishment of the first chair of Ancient History in 1863 to the death of the last deceased incumbent in 1976. From 1863 to 1945, this discipline was part of the Department of History, and afterwards, together with Classical Philology (and more recently also Classical Archaeology), part of the Institute of Classics. In addition to biographical information, the text also reports on the research foci of the chair holders and describes their work in Kiel against the background of general political, intellectual-historical and disciplinary as well as research developments. On the one hand, it becomes apparent that Kiel served as a springboard for many chair holders to pursue an academic career at more prestigious universities. On the other hand, the research shows that, although each chair holder set his own accents in teaching and research, certain priorities were pursued repeatedly nontheless, namely the study of epigraphic, numismatic, and papyrological evidence (compare for instance Max Leberecht Strack, Paul Leberecht Strack, Herbert Nesselhauf, Horst Braunert et al.) and the attempt to embed the cultures of Greece and Rome within larger cultural and political contexts and to understand the world of Eurasia as a manyfold interconnected world (compare Alfred von Gutschmid, Hugo Prinz). Incidentally, both approaches characterize Ancient History in Kiel until today

Mani und Aristoteles. Das sechste Kapitel der koptischen Kephalaia, Textanalyse und Interpretation. Wiesbaden, Harrassowitz, 2002, VI-368 p., bibliogr. (Göttinger Orientforschungen. IV. Reihe : Ägypten 42).

Dans son examen détaillé du contenu et de la structure du sixième chapitre des « Kephalaia » coptes qui traite du mal en soi et de ses manifestations, l’A. a réussi à éclaircir les macro- et superstructures de ce texte « obscurci » et marqué par un langage symbolique très prononcé et elle a révélé son arrière-plan mythologique, philosophique et théologique. Le travail évoque non seulement les solutions manichéennes apportées aux problèmes de l’être, de la Pérennité et du Non-être, mais il dém..

Epiregulin expression and secretion is increased in castration-resistant prostate cancer.

INTRODUCTION In prostate cancer, long-term treatment directed against androgens often leads to the development of metastatic castration-resistant prostate cancer, which is more aggressive and not curatively treatable. Androgen deprivation results in elevated epiregulin expression in LNCaP cells which is a ligand of EGFR. This study aims to reveal the expression and regulation of epiregulin in different prostate cancer stages enabling a more specific molecular characterization of different prostate carcinoma types. METHODS Five different prostate carcinoma cell lines were used to characterize the epiregulin expression on the RNA and protein levels. Epiregulin expression and its correlation with different patient conditions were further analyzed using clinical prostate cancer tissue samples. Additionally, the regulation of epiregulin biosynthesis was examined at transcriptional, post-transcriptional and release level. RESULTS An increased epiregulin secretion is detected in castration-resistant prostate cancer cell lines and prostate cancer tissue samples indicating a correlation of epiregulin expression with tumor recurrence, metastasis and increased grading. Analysis regarding the activity of different transcription factors suggests the involvement of SMAD2/3 in the regulation of epiregulin expression. In addition, miR-19a, -19b, and -20b are involved in post-transcriptional epiregulin regulation. The release of mature epiregulin occurs via proteolytic cleavage by ADAM17, MMP2, and MMP9 which are increased in castration-resistant prostate cancer cells. DISCUSSION The results demonstrate epiregulin regulation by different mechanism and suggest a potential role as a diagnostic tool to detect molecular alterations in prostate cancer progression. Additionally, although EGFR inhibitors false in prostate cancer, epiregulin could be a therapeutic target for patients with castration-resistant prostate cancer

Stromal-epithelial interaction induces GALNT14 in prostate carcinoma cells

IntroductionCell-cell communication is an important process in healthy tissue but also gains enhanced attention regarding pathological tissue. To date, the tumor microenvironment is gradually brought into focus when studying tumorigenesis. In the prostate gland, stromal and epithelial cells greatly interact to maintain homeostasis or tissue integrity. This study focuses on an indirect communication via soluble factors.MethodsTo investigate the cell-cell interaction via soluble factors, the prostate carcinoma cell line LNCaP and the stromal primary cells p21 were co-cultured without direct contact and RNA was isolated at defined time points. Differences in gene expression were finally analyzed by RNA sequencing.ResultsRNA sequencing revealed a time-depending differential expression profile. Selected factors were subsequently characterized at molecular level and analyzed in human prostate tissue of different developmental stages as well as pathology. GALNT14 was one of the highest induced co-culture-specific genes in LNCaP cells. Detection in healthy tissue and BPH revealed an age-dependent decrease in GALNT14 expression. Moreover, in prostate carcinoma, GALNT14 expression heavily varied independent of the Gleason score.ConclusionOverall, this work provides a basis for further studies related to paracrine stromal-epithelial interaction in prostate carcinoma and highlights the importance of GALNT14

Faserverbund-Leichtbau mit Automatisierter Mikrowellenprozesstechnik hoher Energieeffizienz (FLAME) : Schlussbericht des BMBF-Verbundprojektes (KIT Scientific Reports ; 7701)

Faserverstärkte Kunststoffe finden Anwendung in Luft- und Raumfahrt, Automobil, Maschinenbau und Sport. Das Anwendungspotential ist jedoch noch lange nicht erschöpft, auch wegen zu hoher Bauteil- bzw. Herstellungskosten. Um dem existierenden Kostendruck Rechnung zu tragen, gewinnen die Aspekte der Automatisierung und Effizienzsteigerung immer mehr an Bedeutung. Die Ergebnisse des Verbundprojektes FLAME zeigen, dass durch Einsatz von Mikrowellen im Prozess hier deutliche Vorteile erreicht werden