Showing papers by "Bielefeld University published in 1975"

Reexamination of the perfectness concept for equilibrium points in extensive games

Abstract: The concept of a perfect equilibrium point has been introduced in order to exclude the possibility that disequilibrium behavior is prescribed on unreached subgames [Selten 1965 and 1973]. Unfortunately this definition of perfectness does not remove all difficulties which may arise with respect to unreached parts of the game. It is necessary to reexamine the problem of defining a satisfactory non-cooperative equilibrium concept for games in extensive form. Therefore a new concept of a perfect equilibrium point will be introduced in this paper2).

Relative Entropy of States of von Neumann Algebras

Abstract: Relative entropy of two states of a von Neumann algebra is defined in terms of the relative modular operator. The strict positivity, lower semicontinuity, convexity and monotonicity of relative entropy are proved. The Wigner-Yanase-Dyson-Lieb concavity is also proved for general von Neumann algebra.

Interactions of heteroaromatic compounds with nucleic acids. 2. Influence of substituents on the base and sequence specificity of intercalating ligands.

Abstract: This paper presents the results of a systematic study on the effects of substituents on the base and sequence specificity of tricyclic heteroaromatic compounds interacting with DNA by intercalation. All the compounds tested are derived from proflavine and acridine orange analogs with different heteroatoms in the middle ring. Their base and sequence specificities were determined by differential dialysis of the ligand against DNA samples of differing G · C content. The main results indicate that (a) the introduction of a phenyl substituent into one of the two available positions of the middle ring increases or decreases the G · C specificity of the ligand depending on the position where the substitution takes place; (b) compounds of the substitution type of neutral red (2-methyl-3-amino-7-dimethyl-amino-phenazine) show unexpectedly high G · C specificities and (c) DNA ligands of pronounced sequence specificity for adjacent G · C pairs can be constructed by combining the structural elements of neutral red with an additional phenyl residue in the same molecule. The further study of compounds related to the phenylated neutral red revealed that the G · C specificity can be improved or destroyed by additional substituents. The comparison of the G · C specificity and the DNA-affinity data of the compounds studied leads to the suggestion that the specificity arises mainly from electronic factors which are strongly controlled through steric constraints on possible complex geometries. As a basis for the discussion a possible structure for the DNA complex of the phenylated neutral red is considered in which the extra phenyl ring at N-5 of the phenazinium system, protrudes into the large groove of the DNA helix while the tricyclic part of the ligand is inserted between the DNA base-pairs.

The tracing procedure: A Bayesian approach to defining a solution forn-person noncooperative games

Abstract: The paper proposes a Bayesian approach to selecting a particular equilibrium points * of any given finiten-person noncooperative game Γ as solution for Γ. It is assumed that each playeri starts his analysis of the game situation by assigning a subjective prior probability distributionp j to the set of all pure strategies available to each other playerj. (The prior distributionsp j used by all other playersi in assessing the likely strategy choice of any given playerj will be identical, because all these playersi will compute this prior distributionp j from the basic parameters of game Γ in the same way.) Then, the players are assumed to modify their subjective probability distributionsp j over each other's pure strategies systematically in a continuous manner until all of these probability distributions will converge, in an appropriate sense, to a specific equilibrium points * of Γ, which, then, will be accepted as solution. A mathematical procedure, to be called thetracing procedure, is proposed to provide a mathematical representation for this intellectual process of convergent expectations. Two variants of this procedure are described. One, to be called thelinear tracing procedure, is shown to define a unique solution in “almost all” cases but not quite in all cases. The other variant, to be called thelogarithmic tracing procedure, always defines a unique solution in all possible cases. Moreover, in all cases where the linear procedure yields a unique solution at all, both procedures always yield the same solution. For any given game Γ, the solution obtained in this way heavily depends on the prior probability distributionsp 1,...,p n used as a starting point for the tracing procedure. In the last section, the results of the tracing procedure are given for a simple class of two-person variable-sum games, in numerical detail.

Polarized Electron-Electron Scattering at GeV Energies

Abstract: The longitudinal polarization of the new Yale University-Stanford Linear Accelerator Center polarized-electron beam has been determined at laboratory energies between 6.47 and 19.40 GeV. Spin-dependent elastic electron-electron scattering (M\o{}ller scattering) has been found to be a practical technique for polarization measurements at high energies. The results are consistent with the energy and angular dependence predicted by quantum electrodynamics and with an energy-independent beam polarization of 0.76\ifmmode\pm\else\textpm\fi{}0.03.

Die keulenförmigen Sensillen auf den Cerci der Grille Gryllus bimaculatus als Schwererezeptoren

Abstract: 1. Die Sinneskeulen sind durch eine Sinneszelle innerviert, die phasischtonische Reizantworten zeigt. Die grosten Anderungen der Impulsfrequenzen entstehen bei Ablenkung der Keulen in ihrer mechanischen Vorzugsebene. Die kleinste Auslenkung, die noch Impulsfrequenzanderungen hervorruft, betragt 0,1°. Die Anstiegssteilheit des Reizes verandert die Hohe der phasischen Antwort. Auf Sinusreize antwortet der Rezeptor bis 300 Hz mit reizsynchronen Impulssalven. 2. Gemeinsam mit Impulsen des ableitenden Nerven konnten Impulse der an der Basis der Keulenbecher liegenden campaniformen Sensillen abgeleitet werden. Ihre Erregungsmuster sind phasisch, sie sprechen auf Bewegung des Bechers, nicht aber der Keulen allein an. 3. Keulenformige Sensillen konnen prinzipiell die Lage der Grille im Schwerefeld messen. Dies wird indirekt durch die Messung der Ablenkung der Keule im Schwerefeld und die Registrierung der Amplitudenkennlinie, und direkt durch die Ableitung der Nervenimpulse wahrend der Drehung des Tieres im Schwerefeld bewiesen.

Investigation of the repetitive sequences in calf DNA by cleavage with restriction nucleases.

Abstract: Calf thymus DNA was digested with the restriction nucleases from Escherichia coli carrying resistance transfer factor I, Haemophilus influenzae Rd and Bacillus subtilis X5 (EcoRI, Hind II, and Bsu, respectively) and submitted to polyacrylamide gel electrophoresis. About 10% of the DNA migrated as discrete fragments in 8, 16, and 30 bands, respectively, superimposed upon a continuous distribution of various size DNA fragments. The fragments within the bands are repeated 2000 to 160000 times in the haploid genome. Their sizes range from about 10 to a few thousand nucleotide pairs. About 5% of the DNA in EcorRI and Hind II digests migrated in a band at the position of undigested DNA, probably due to the resistance of long stretches of DNA against these nucleases. Calf DNA fragments obtained with EcoRI and Hind II were isolated by preparative gel electrophoresis. DNA from the bands showed the behaviour of repetitive DNA in renaturation experiments. An EcoRI fragment 1300-nucleotide-pairs long, which represents 6% of the calf genome and occurs 130000 times, is tandemly repeated (derived from the satellite of 1.714 g/cm3, see below). Another EcoRI fragment of 970 nucleotide paris, which represents 0.5% of the calf genome and is derived from the DNA of 1.710 g/cm3 seems to be structurally related to the foregoing fragment since it shows a similar Hind II and Bsu cleavage pattern. It alternates with a 1550-nucleotide-pairs-long EcoRI fragment. In another series of experiments total calf DNA was separated into main-band and satellite fractions by density-gradient centrifugation and chromatography in the presence of a base-specific dye. Purified fractions were characterized by analytical ultracentrifugation and by Hind II and EcorRI digestions. From the cleavage patterns of purified fractions an assignment of the bands found with total calf DNA to satellite fractions was possible. Most fragments were derived from the components of density 1.709 and 1.710 g/cm3. The 1.714-g/cm3 satellite was cleaved into a 1300-nucleotide-pairs-ling EcorRI fragment and two Hind II fragments of 1100 and 180 nucleotide pairs. The satellites of 1.723 g/cm3 and 1.705 g/cm3 were not cleaved by either Hind II or EcoRI DNAase. On digestion of main band DNA with Bsu a 160-nucleotide-pairs-long fragment was obtained which was also observed, at a frequency of about 160000, in the Bsu digest of EcoRI fractions from total calf DNA.

Resistenz und Rezeptivität der Wissenschaft - Zu den Entstehungsbedingungen neuer Disziplinen durch wissenschaftspolitische Steuerung

Abstract: Die Wissenschaftspolitik der Gegenwart ist 'produktwertorientiert'; sie versucht, wissenschaftliche Entwicklung auf die Losung spezifischer, politisch definierter Probleme hin zu orientieren (z. B. Krebsforschung, Fusionsforschung). In einer dimensionalen Analyse werden auf der Ebene der politischen Steuerungsintentionen der kognitiven und der institutionellen Strukturen der Wissenschaft Variablen entwickelt, mit deren Hilfe politisch induzierte Bildung von Spezialgebieten komparativ beschrieben werden kann. Es werden Abhangigkeitsbeziehungen zwischen politischen Steuerungsintentionen und kognitiven und sozialen Wissenschaftsstrukturen konstruiert. Die Gegenuberstellung von technischen Anspruchen verschiedener Komplexitat, die in den politischen Problemstellungen impliziert sind, und verschiedenen kognitiven Entwicklungsstufen wissenschaftlicher Disziplinen ergibt ein Modell erster Naherung fur die Bestimmung von Rezeptivitat bzw. Resistenz einer Wissenschaft gegenuber extern gesetzten Problemstellungen.

Characterization of particles by means of local observables

Abstract: We introduce the notion of singly localized states and use it to characterize the one-particle states as those states which are singly localized at all times. For theories which satisfy the Haag-Swieca compactness criterion, we show that a state has a discrete mass spectrum if and only if it is a "geo- metrical one-particle state". Using a mathematical description of coincidence arrangements of counters we show that in asymptoticall y complete theories the asymptotic particle number is the asymptotic number of localization centres.

Die Kristall- und Molekülstruktur von 2-Amino-2,4,4,6,6-pentafluor-1,3,5,2λ5,4λ5,6λ5-triazatriphosphorin

Abstract: Die Struktur der Titelverbindung 1 wurde aus Diffraktometer-Einkristalldaten nach direkten Methoden bestimmt und fur 1465 Reflexe zu einem R-Wert von 3.8% verfeinert. Die Verbindung kristallisiert monoklin in der Raumgruppe P21/c mit den Gitterkonstanten a = 7.958 A, b = 5.222 A, c = 19.297 A, β = 101.24° Z = 4. Der PN-Sechsring ist schwach gewellt. Die endocyclischen PN-Abstande weisen signifikante Unterschiede auf (Einzelwerte: 1.551 1.586 A, Mittelwert: 1.565 A). Der Mittelwert der PF-Bindungslangen betragt 1.521 A, die Lange der PNAmin-Bindung ist 1.601 A. Die Molekule sind schichtartig uber NH N-Wasserstoffbrucken verknupft. The Crystal and Molecular Structure of 2-Amino 2,4,4,6,6,-pentafluoro-1,3,5,2λ5, 4λ5, 6λ5- triazatriphosphorine The crystal structure of the title compound 1 has been determined by direct methods from single crystal X-ray data and has been refined to R = 0.038 for 1465 reflections. The compound crystallizes in the monoclinic space group P21/c. The molecule forms a slightly puckered six-membered (PN)3 ring. The endocyclic PN bond lengths are significantly different (mean: 1.565 A). The mean PF bond length is 1.521 A, the PNamine bond length is 1.601 A. The molecules are connected as layers through NH N hydrogen bonds.

In vitro development from sporozoites to first-generation merozoites in Eimeria contorta Haberkorn, 1971. A fine structural study.

Abstract: The asexual development of Eimeria contorta from sporozoites to first-generation merozoites in tissue culture was investigated with the electron microscope. Sporozoites with a three-layered pellicle, 26 subpellicular microtubules, a conoid, 4-7 rhoptries, and an abundance of micronemes actively entered host cells and showed direct contact to the host cell's cytoplasm. Shortly after penetration, small vacuoles surrounding the parasite merged into a parasitophorous vacuole. Inside this vacuole, sporozoites assumed a definite U-shape before transformation into schizonts took place. This process was characterised by the occurrence of subpellicular microtubules exclusively in the anterior half of the sporozoite, by a degeneration of the 2 inner pellicular membranes, by an outpocketing of the parasite's surface, and by the arrangement of microtubules in clusters. About 25 merozoites were formed at the surface of mature schizonts, to which they remained attached at their posterior pole. A polar ring was present at that area. Anterior and posterior refractile bodies were conspicuous in merozoites and showed close association with mitochondria. The significance of a fibrillar substructure in rhoptries and micronemes is discussed, and special attention is drawn to the pathway of nutrient transport from host cell mitochondria and dictyosomes through intravacuolar folds, parasitophorous vacuole and crescent body into the parasite's food vacuoles.

Gonadenentwicklung beim Wellensittich,Melopsittacus undulatus unter verschiedenen Lichtbedingungen

Abstract: Bei domestizierten Wellensittichen wurde die Keimdrusenreifung an jungen Mannchen unter Langtag- und Kurztagbedingungen (LD 16:8 bzw. 8:16) verfolgt. Im Alter von 3 1/2 bis 4 Monaten treten die ersten reifen Spermien auf. In der Kurztag-Gruppe scheint die Tendenz einer schwachen Entwicklungsverzogerung erkennbar. Mit zunehmendem Alter vergrosert sich die anfangs geringe individuelle Variabilitat erheblich. Eine grundsatzliche fotoperiodische Steuerung bei der Gonadenentwicklung der Mannchen kann nicht gefunden werden. Die Ergebnisse werden diskutiert und mit Befunden bei anderen Arten verglichen.

On a dynamical scheme of multiparticle processes

Abstract: Physical content is given to a multiparticle decay scheme of a fireball into pions and/or clusters of pions which was developed previously. Energy-momentum conservation coupled to the assumption of a sequential decay mode leads to a set of dynamical equations directly for physical quantities.

Hodenreife, Prachtkleid und Schnabelfärbung beim Oryxweber ( Euplectes orix )

Abstract: Die Hodenentwicklung des sudafrikanischen WebersEuplectes orix wurde histologisch untersucht und zur Entwicklung des Prachtkleides und zur Umfarbung des Schnabels in Beziehung gesetzt. Es zeigte sich, das alle drei Faktoren miteinander positiv korreliert sind, das jedoch die Schnabelfarbe am besten geeignet ist, als Indikator fur die Fortpflanzungsreife bei freilebenden Populationen dieser Art zu dienen.