Oscillations of Short Periods in Neutron and Strange Stars

We present a model of a remnant of supernova, and we analyze the correlation with the observational data to short periods oscillations between a neutron star and a strange matter star. The results confirm previous conclusions.     

Local connectivity functions on arcwise connected spaces and certain continua

Types of spaces are given on which every local connectivity function is a connectivity function, a connected function, or a Darboux function. A complete determination such spaces is obtained when the spaces are assumed to be arc-like continua or circle-like continua. Results provide answers to a question asked by Stallings.     

Mean relaxation time approximation for dynamical correlation functions in stochastic systems near instabilities

The linewidth factor of the order parameter autocorrelation function for the mean fieldn-vector Ginzburg-Landau model is determined numerically forn>2. This generalizes results for the single mode laser (n=2) obtained in Part II [Nadler, W., Schulten, K.: Z. Phys. B—Condensed Matter].     

Minimal 2-Fold Coverings of E d

Let N(k, d) be the smallest positive integer such that given any finite collection of open halfspaces which k-fold coversE ^d , there exists a subcollection of cardinality less than or equal toN(k,d) which k-fold coversE ^d . A well-known corollary to Helly's theorem proves N(1,d) =d+1. This provides an inductive base from which we show N(k; d) exists for all positive integers k.Our main result is .     

Analysis of individual natural pyrethrins in indoor matrices by HRGC/ECD

An HRGC/ECD method is presented which permits the identification and quantitation of individual components of pyrethrins (cinerin I, jasmolin I, pyrethrin I, cinerin II, jasmolin II, pyrethrin II) in indoor matrices (airborne particles, house dust) after application of an agent containing pyrethrum. In order to prepare calibration standards for the individual components of the pyrethrum extract, the pyrethrins were isolated hy semi-preparative HPLC and their content and purity were determined by ¹H-NMR spectroscopy.     

THE MECHANISM OF THE 9,10-DIBROMOANTHRACENE MEDIATED TRIPLET-SINGLET ENERGY TRANSFER IN THE TETRAMETHYL-1,2-DIOXETANE ENERGIZED RUBRENE LUMINESCENCE*

Abstract— The ternary chemiluminescent system consisting of tetramethyl-dioxetane (TMD), 9 ,10-dibromoanthracene (DBA) and rubrene (Ru) has been investigated in benzene solution and in polystyrene matrices. DBA has been found to mediate the energy transfer between excited triplet acetone (³K), generated from TMD, and rubrene resulting in the enhancement of the Ru emission and reduction in the DBA emission. A detailed kinetic analysis confirms that ca. 50% of the enhanced chemilumines-cence involves triplet-singlet (TS) energy transfer from ³K to DBA, followed by singlet-singlet (SS) energy transfer from DBA to Ru, the remainder ca. 50% being due to reabsorption of DBA fluorescence by rubrene. It is concluded that the TS energy transfer is of the resonance type, occurring with a rate of k^TS_K.DBA= (1.4 ± 0.4) ± 10⁹M^-1s^-1 and an efficiency of ø^TS_K.DBA= 0.3 ± 0.1. As expected, the SS energy transfer is also of the resonance type, taking place at comparable rates in benzene solution and in polystyrene matrices, is. k^SS_DBARU= 1.5 ± 10¹⁰ M^-1 and (2.2 ± 0.2) ± 10¹⁰M^-1s^-1, respectively.     

Conformations of laulimalide in DMSO-d6

Laulimalide is one of the newest naturally occurring macrolides known to act as a microtubule stabilizing agent with properties similar to Taxol. It also stands as being one of the most flexible with 18 rotatable bonds. This large number of rotatable bonds allows for approximately 3(18) potential conformers. To examine the conformational energy surface of laulimalide, we have performed an NAMFIS deconvolution analysis for laulimalide in DMSO-d6. The latter has been supplemented with a post-NAMFIS energy analysis at the Becke3LYP/6-31G level that examines the opposing effects of internal hydrogen bonding and syn-pentane interactions. In this way, we have identified 15 laulimalide conformations that can be classified into 5 different families: Supine, Convex, Cobra, Stretch, and Concave motifs.     

Mikrogravimetrische Trennung von Zink und Uran

Zusammenfassung Im Zusammenhange mit der Bestimmung des Gehaltes schwach radioaktiver Mineralien an Blei, Thorium und Uran, dessen Ermittlung zur geologischen Zeitmessung nach der sog. Bleimethode erforderlich ist, wurde eine Trennung von Zink und Uran ausgearbeitet. Beide Elemente kommen in diesen Mineralien im Betrage von meist nur wenigen Hundertstelprozenten vor.Die Trennung wird in der Weise ausgeführt, daß das Zink nach dem Vorbild der makroanalytischen Arbeitsvorschrift vonC. Mayr in mit Monochloressigsäure und Natriumacetat gepufferter Lösung als Zinksulfid abgeschieden und nach Auflösen des Niederschlages in Salzsäure als Zinkammoniumphosphat bestimmt wird. Das uranhaltige Filtrat des Zinksulfids wird eingedampft und der Rückstand mit Salzsäure und Bromwasser abgeraucht, worauf man in essigsaurer ammonacetathaltiger Lösung das Uran in bekannter Weise als Uranyloxychinolat bestimmt.

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Summary In connection with the determination of the lead, thorium and uranium content of feebly radioactive minerals, a knowledge of which is necessary for the measurement of geological time by the so-called lead method, a separation of zinc from uranium has been worked out. Both these elements only occur to the extent of a few hundredths of one per cent in the minerals in question. The separation is carried out by precipitating the zinc according toC Mayr's macro procedure as zinc sulphide in a solution buffered with monochloracetic acid and sodium acetate; the precipitate is redissolved in hydrochloric acid, and the zinc determined as zinc ammonium phosphate. The filtrate containing the uranium is evaporated, and treated with hydrochloric acid and bromine water. The uranium is then determined by precipitation in the usual way with 8-hydroxyquinoline in acetic acid solution containing some ammonium acetate.

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Résumé Il a été établi une séparation du zinc et de l'uranium en connexion avec la détermination de la teneur en plomb, thorium et uranium de minéraux faiblement radio-actifs dont la mise au point était nécessaire à la détermination de l'âge géologique, d'après la méthode appelée Méthode au Plomb. Ces deux éléments se trouvent dans ces minéraux dans un rapport ne dépassant pas, pour la plupart du temps, quelques centièmes %.La séparation est conduite de telle manière que le zinc soit précipité sous forme de sulfure de zinc dans une solution tamponnée par de l'acide monochloracétique et le l'acétate de soude en se basant sur le mode de travail macroanalytique deC. Mayr. Après dissolution du précipité dans l'acide chlorhydrique, on détermine le zinc comme phosphate zinco-ammonique. Le filtrat contenant l'uranium est concentré et le résidu est évaporé à sec avec de l'acide chlorhydrique et de l'eau de Brome. Ensuite, on détermine l'uranium de la manière bien connue comme oxyquinoléate d'uranyle en solution acétique contenant de l'acétate d'ammonium.