Thirty-Element Active Antenna Array as a Prototype of a Huge Low-Frequency Radio Telescope

An effective wide-band (10 to 60 MHz) active antenna element has been developed. The cost of one short (3 m), thin dipole with built-in amplifier and metal construction is less than 45 euro. It was shown both theoretically and experimentally that the upper limiting frequency is at least 60 MHz, the dynamic range is 90 dB/V and the share of the amplifier noise to the background antenna temperature is about 10%. The developed active dipole was tested by building a 30-element antenna array and comparing its parameters with one of the subpart of the UTR-2 radio telescope having passive dipoles of 8.6 m in length and 1.8 m in diameter. The 3C461 ionospheric scintillation spectra observed in the experiments show that the sensitivities and noise-immunities of both antennas are close. This proves the availability using of a short cheap active dipole in new generation giant radio telescopes.     

Implications of Stratigraphic and Paleoclimatic Records of the Last Interglaciation from the Nordic Seas

Climatic reconstruction of glacial to interglacial episodes from oxygen isotopes in sediment cores from the Nordic seas is complicated by strong local meltwater contributions to the oxygen isotope changes. Combination of benthic and planktic foraminiferal isotope data with foraminiferal abundances and ice-rafted debris (IRD) allows separation of local and global effects and subdivision of the marine oxygen isotope events 6.2–5.4, which include the last interglaciation, into: (1) a meltwater phase after glacial stage 6, recorded by large amounts of IRD and low foraminiferal abundance, indicating surface water warming; (2) an IRD-free period with high deposition rates of subpolar foraminifera and other CaCO₃pelagic components, recognized here as the “full” interglaciation; and (3) a phase with the recurrence of IRD and the demise of subpolar species. Comparison of ice-core records and marine data implies that the global climate during the last full interglaciation and that during the postdeglacial Holocene were similar. The records show no significantly different variations in the proxy data. In contrast, the oxygen isotopes of planktic foraminifera and ice cores indicate significant differences during each of the deglacial transitions (Terminations I and II) that preceded these two interglaciations. These suggest that during Termination II the climatic evolution in the Nordic seas was less affected by abrupt changes in ocean–atmosphere circulation than during the last glacial to interglacial transition.     

Automatisches Grundwasserbilanzmodell Münchener Schotterebene

Zusammenfassung Das automatische Grundwasserbilanzmodell berechnet und stellt die Grundwasserverhältnisse und die Grundwasserbilanz des Großraumes München mit Hilfe der finiten Element-Methode dar. Es werden mit dem Modell genaue Angaben über die jetzige und zukünftige qualitative und quantitative Grundwassernutzung ermöglicht.

---

Using the finite element method, the automatic mathematical model enables a calculation of the water budget and prints automatically a map of the whole ground water bodies in the region of Munich (Germany).The model makes it possible to gain exact information regarding the quantitative and qualitative water supply conditions in the present as well as in future.

---

Résumé Le modèle automatique du bilans en eau souterraine calcule et fixe les rapports et bilans en eau souterraine de la région de Munich (Allemagne) par la méthode des éléments finis. Ce modèle permet de fournir des données précises concernant la qualité et la quantité de l'eau souterraine utilisable actuellement et dans l'avenir.

---

«finites Element» . .

     

Magma und magmatogene Lösungen

Zusammenfassung Es werden die mit den im Magma gelösten flüchtigen Komponenten zusammenhängenden Erscheinungen wie Intrusion der Magmen, Bildung von Pegmatiten, Abgabe der flüchtigen Komponenten aus dem Magma und Bildung von hydrothermalen Lösungen diskutiert.

---

Phenomena connected with the presence of volatile components of magmas are discussed: Magmatic intrusion, pegmatite-formation, loss of volatile agents from the melt and, formation of hydrothermal solutions.

---

Résumé L'auteur discute le rôle des composants volatils dans le magma, l'intrusion du magma, la formation des pegmatites et des solutions hydrothermales

---

, .: .