bluuebunny/crossref_metadata_2025 huggingface dataset:
Wnt ligands from the embryonic surface ectoderm regulate ‘bimetallic strip’ optic cup morphogenesis in mouse
Authors: Carpenter April C. , Smith April N. , Wagner Heidi , Cohen-Tayar Yamit , Rao Sujata , Wallace Valerie , Ashery-Padan Ruth , Lang Richard A.
Published: February 2015

The Wnt/β-catenin response pathway is central to many developmental processes. Here, we assessed the role of Wnt signaling in early eye development using the mouse as a model system. We showed that the surface ectoderm region that includes the lens placode expressed 12 out of 19 possible Wnt ligands. When these activities were suppressed by conditional deletion of wntless (Le-cre; Wlsfl/fl) there were dramatic consequences that included a saucer-shaped optic cup, ventral coloboma, and a deficiency of periocular mesenchyme. This phenotype shared features with that produced when the Wnt/β-catenin pathway co-receptor Lrp6 is mutated or when retinoic acid (RA) signaling in the eye is compromised. Consistent with this, microarray and cell fate marker analysis identified a series of expression changes in genes known to be regulated by RA or by the Wnt/β-catenin pathway. Using pathway reporters, we showed that Wnt ligands from the surface ectoderm directly or indirectly elicit a Wnt/β-catenin response in retinal pigment epithelium (RPE) progenitors near the optic cup rim. In Le-cre; Wlsfl/fl mice, the numbers of RPE cells are reduced and this can explain, using the principle of the bimetallic strip, the curvature of the optic cup. These data thus establish a novel hypothesis to explain how differential cell numbers in a bilayered epithelium can lead to shape change.
Syntheses, Structures, and Properties of Biphosphinines Tethered Aromatic π-System
Authors: Nagahora Noriyoshi , Ogawa Tamaki , Honda Maki , Fujii Motomi , Tokumaru Hiroshi , Sasamori Takahiro , Shioji Kosei , Okuma Kentaro
Published: February 2015

The syntheses of a series of biphosphinine derivatives inserted an aromatic π-spacer have been achieved. Their absorption, emission properties, and electrochemical behavior are also disclosed.
The role of globalization in drug development and access to orphan drugs: orphan drug legislation in the US/EU and in Latin America
Authors: Arnold Renée J.G. , Bighash Lida , Bryón Nieto Alejandro , Tannus Branco de Araújo Gabriela , Gay-Molina Juan Gabriel , Augustovski Federico
Published: February 2015

Compared to a decade ago, nearly three times as many drugs for rare diseases are slated for development. This article addresses the market access issues associated with orphan drug status in Europe and the United States in contrast to the legislation in five Latin American (LA) countries that have made strides in this regard--Mexico, Brazil, Colombia, Chile and Argentina. Based on the success of orphan drug legislation in the EU and US, LA countries should strive to adopt similar strategies with regard to rare diseases and drug development. With the implementation of new targeted regulations, reimbursement strategies, and drug approvals, accessibility to treatment will be improved for people afflicted with rare diseases in these developing countries.
Mathematical Models of Project Portfolio Formation: Evolution, Typology, Future
Authors: ��������  , Petrenko Elena
Published: February 2015

The most used models of project portfolio formation have been considered in this work. Models are considered in the order of their emergence, and reasons related to modification of approaches are analyzed. Classification of existing models, allowing mark out existing approaches� advantages and shortcomings, has been offered in this work too.
Virtual Teams: How to Operate a Project at Distance?
Authors: ����������  , Kudryavtseva Ekaterina
Published: February 2015

Virtual project teams� features that affect a project success are considered

in this paper. Most of authors agree that the virtual team success depends

largely on human relationships, solidarity and trust, which construction is

virtual teams� main problem, than on team members technical skills. However,

there are studies which claim that a communications choice determines

the project success. This work purpose is to investigate what factors,

skills and qualities should prevail among virtual team members, in particular

at the team head, which lead to projects successful implementation. Virtual

team formation steps had been formulated based on literature review, interviews

and experiments; features of work, trust importance, and project

manager role had been defined.
Project Activity as a Method of Developing Self-Identification and Communicative Competencies of Pupils in the Information Environment of the Federal State Educational Standards
Authors: ����������  , Gorodilina Tatiana
Published: February 2015

This article presents results of project activity in the conditions of transition to the new structure of the educational standard based on the system-activity

approach. New educational standard makes project activity a compulsory subject � �Individual project�. In this situation different issues and potentials

of educational system, concerning creating space for development of students as actors, were examined. This space is a system for training and development

of personality in educational environment that is important given contemporary level of technical communication systems� penetration into

culture space. This influence the transformation of interpersonal interaction systems, which is commonly connected with cultural codes changings. The

article presents a stepped model of development of project thinking. This model promotes opening of student�s self-actualization and mastering the skill

of self-regulation, that are necessary in project activity.
Bundled Procurement for Technology Acquisition and Future Competition
Authors: Chu Leon Yang , Wang Yunzeng
Published: February 2015

Consider a buyer who would like to procure certain products for the current period and the underlying technologies so that he can become a supplier and compete with current suppliers in the future market. One potential procurement mechanism for such a buyer is to bundle the procurement project with technology acquisition. We propose a dynamic stochastic game-theoretic model that analyzes the optimal technology offer strategies of the asymmetric suppliers and highlights how the size of the current project, relative to the size of the future market, and supplier competition determine the effectiveness of the bundled procurement mechanism for the buyer. For the two-supplier case, we find that each supplier has a dominant technology offer strategy that is independent of the opponent’s strategy. When the relative size of the project is small, suppliers only offer obsolete technologies even if their technologies are perfect substitutes. While suppliers offer better technologies as the project size increases, their responses in technology offers are not continuous with respect to the project size—once the project size reaches some threshold, suppliers’ optimal responses jump to their best technologies. We also observe that the premium needed for technology acquisition under the bundled procurement mechanism can be negligible compared to the expected profit from the future market.
Always and already excessive: Theorizing diva performativity in a TAMU studio soprano
Authors: Adamy Hannah P.
Published: February 2015

There is no word that brings to mind simultaneous bodily, vocal and affect excess quite like ‘diva’. Contrary to popular belief, the opera diva’s behaviours both in and outside performance are results of her training and the Euro-classical repertoire. On the levels of the body, voice and affect, the student soprano studies and performs a particular kind of ‘divaness’. She inures herself into a particular tradition that teaches discipline through repertoire. Through an analysis of Euro-classical pedagogical discipline on a soprano’s body, voice and affective display, this article presents a theory of diva performativity using Judith Hamera’s definition of virtuosity, Roland Barthes’ ‘The grain of the voice’, Wayne Koestenbaum’s discussion of ‘divaness’, and Naomi Cumming’s illuminations of Richard Schechner’s ‘not me, not not me’. At these levels, a soprano’s vocal study teaches her to be always and already excessive.
California’s first year with local control finance and accountability
Authors: Menefee-Libey David , Kerchner Charles Taylor
Published: February 2015

In 2013, Governor Jerry Brown and the California legislature radically restructured the state’s school funding system and accountability systems with a weighted student formula and a mandated local planning process in each district. The new law substitutes local politics and grassroots agency for state-driven mandates and compliance reviews. While the Local Control Funding Formula has had immediate impact, early evaluations suggest that districts like the new system and are earnest in their implementation efforts, but it will take years to assess the effect of the multi-indicator Local Control Accountability Plans. Simultaneously, the state is implementing the Common Core State Standards and the associated Smarter Balanced Assessment Consortium tests, which make creating local accountability plans more complicated.
New accountability in California through local control funding reforms: The promise and the gaps
Authors: Affeldt John T.
Published: February 2015

California is in the midst of the nation’s most significant current overhaul of a state school funding and accountability system. This paper examines the state’s recent reforms enacted through the Local Control Funding Formula (LCFF) against the new accountability framework articulated by Linda Darling-Hammond, Gene Wilhoit, and Linda Pittenger in their August 2014 paper in this publication.  There the authors addressed the need for states to align their accountability systems with new college and career-ready learning standards through “a focus on [1] meaningful learning, enabled by [2] professionally skilled and committed educators, and supported by [3] adequate and appropriate resources” (Darling-Hammond, Wilhoit, & Pittenger, 2014). Many key aspects of LCFF align California with the vision of a new accountability that promises to prepare the state’s students with 21st century college and career ready skills; other key building blocks must yet be put in place if California and its students are to realize the promise of the new paradigm.
River-Crabbed Shitizens and Missing Knives: A Sociolinguistic Analysis of Trends in Chinese Language Use Online as a Result of Censorship
Authors: Wozniak Audrey M.
Published: February 2015

In today’s digital age, the online public domain, particularly social networking websites, is the new frontier for the battle between censors and dissidents. This paper examines linguistic trends in the ways in which Chinese web users exploit Chinese phonology, morphology, and orthography to avoid notice by online censors through the lenses of pragmatics and critical discourse analysis. The linguistic transformations can be divided into 1) phonologically derived transformations, e.g. the well known “river crab” (héxiè, 河蟹) in place of the word “harmony” (héxié, 和谐); 2a) character suggestion (phono-orthographical) e.g. referring to former Chinese Premier Wen Jiabao (Wēn Jiābǎo, 温家宝) as “Teletubby” (tiānxiàn bǎobǎo, 天线宝宝) because of the two names’ shared character 宝 (bǎo); and 2b) character suggestion (morpho-orthographical) e.g. the made-up word 目田 (mù tián, “eye field”) being substituted for 自由 (zìyóu, “freedom”). Consequently, introducing multiple linguistic transformations, in particular introducing elements of foreign languages and ideograms, drastically increases the level of encoding. This paper presents examples of combination methods, including Chinese-English compound words that connote disparate yet interdependent meanings in multiple languages meanings, as well as the youth culture phenomenon of Martian language, or 吙☆魰 (火星文, huǒxīng wén). In characterizing the ways in which web users manipulate Chinese language, this paper aims to demonstrate that these transformation techniques are inherent to the Chinese language as well as a byproduct of the relationship between web users and censors, reflected in the encoded subversive messages heavy reliance on political and cultural references. Thus, interpreting the output strings of subversive messages requires both linguistic knowledge and social context.
Minimal resolutions, Chow forms and Ulrich bundles on K3 surfaces
Authors: Aprodu Marian , Farkas Gavril , Ortega Angela
Published: February 2015

The Minimal Resolution Conjecture (MRC) for points on a projective variety X predicts that the Betti numbers of general sets of points in X are as small as the geometry (Hilbert function) of X allows. To a large extent, we settle this conjecture for a curve C with general moduli. We then proceed to find a full solution to the Ideal Generation Conjecture for curves with general moduli. In a different direction, we prove that

K
⁢
3

K3

surfaces admit Ulrich bundles of every rank. We apply this to describe a pfaffian equation for the Chow form of a

K
⁢
3

K3

surface.
Neurological disease or intellectual disability among sons of female Swedish dental personnel
Authors: Vähäsarja Niko , Montgomery Scott , Sandborgh-Englund Gunilla , Ekbom Anders , Ekstrand Jan , Näsman Peggy , Naimi-Akbar Aron
Published: February 2015

Prenatal exposure to elemental mercury may be a potential hazard for the offspring of female dental personnel working with dental amalgam. The aim of this study was to investigate whether potential

We used national Swedish registers to investigate risks for diseases potentially related to adverse effects on neurodevelopment. Sons of female dentists (n=1690) and dental nurses (n=10,420) were compared with cohorts consisting of sons of other female healthcare personnel. Due to changes in mercury exposure in dentistry during the study period, analyses were stratified by decade of birth. Hazard ratios (HRs) were calculated using Cox proportional hazard models.

We found no elevated risk for neurological disease, epilepsy or intellectual disability among the sons of dental personnel during any of the decades studied. HRs for neurological disease among the dental nurse cohort were even below 1.00 during the 1970s and 1980s. A low number of events resulted in uncertainty regarding results in the dentist cohort.

We did not find any support for the hypothesis that mercury exposure in Swedish dentistry during the 1960s, 1970s or 1980s had any effect on the incidence of neurological disease or intellectual disability among the sons of female dental personnel. Our results imply that current use of dental amalgam should not represent an elevated risk for neurological disease or intellectual disability among the offspring of dental personnel.
Suszeptibilitätsmessungen an Palladium/Wasserstoff
Authors: Brill P. , Voitländer J.
Published: February 2015

A magnetic balance using the Faraday method and quartz helical springs is described. The susceptibility of the Palladium hydrogen system is investigated within the temperature range from 50 °C to 100 °C. Hydrogen absorption and desorption of a Palladium black sample are caused by varying the hydrogen pressure. The susceptibility and the weight of the sample are observed con­tinuously and fairly near to the equilibrium PdHn/H2 as a function of pressure. The p (n) -isotherms show the well known hysteresis; on the other hand, the χ (n) -isotherms for absorption and desorp­tion coincide and there is no hysteresis. The χ- n relationship is independent of the a→β phase transition. Finally, the results of the susceptibility measurements are compared with the band struc­ture of Pd determined by Hoare and Yates.
Excimerenfluoreszenz oligomerer Assoziate von 3,4-Benzpyren in wäßrigen Lauryl-Sulfonat-Lösungen
Authors: Reske Günter
Published: February 2015

An Lösungen von 3,4-Benzpyren in wäßrigen Na-Laurylsulfonatlösungen wird etwa bei der dop­pelten kritischen Konzentration der Mizellbildung eine langwellige Fluoreszenz beobachtet, deren spektrale Zusammensetzung innerhalb der Toleranz der spektralen Zusammensetzung der Fluoreszenz des festen Kohlenwasserstoffs gleicht.

Wegen der eigenartigen Konzentrationsabhängigkeit wird diese Emission Excimeren zugeschrieben, die sich - in Analogie zum Excimeren-Mechanismus der Festkörperfluoreszenz von 3,4-Benz­ pyren - aus im Grundzustand vorliegenden Assoziaten bilden, die nach der Excimeren-Emission wieder zurückgebildet werden.
Elastische und inelastische Streuung schneller Neutronen am deformierten Kern U -238
Authors: Bühler F.
Published: February 2015

Die elastische Streuung und inelastische Direktprozesse schneller Neutronen an U-238 werden auf der Grundlage eines deformierten optischen Kernpotentials berechnet. Die Festlegung der Formfaktoren dieses Potentials erfolgt durch Verallgemeinerung des äquivalent lokalen Potentials von PEREY und BUCK1 unter Hinzufügung einer kugelsymmetrischen Spin-Bahn-Kopplung. Der Zielkern wird mit dem Kollektivmodell beschrieben, und das gekoppelte System von Schrödin­ gergleichungen für die radialen Wellenfunktionen mit dem verallgemeinerten äquivalent lokalen Potential integriert. Daneben erfolgt eine Übertragung der von FRAHN2 angegebener Schrödinger­ gleichung in effektiver Massennäherung auf deformierte Zielkerne und eine numerische Lösung dieses Gleichungssystems. Die aus diesen Systemen erhaltenen Wirkungsquerschnitte vergleichen wir mit der DWBA-Methode. Der Einfluß höherer Rotationszustände von U-238 auf die elastische und inelastische Streuung wird betrachtet, der Deformationsparameter aus Coulomb-Anregungs-experimenten abgeschätzt und seine endgültige Größe durch Vergleich der Theorie mit Streu­ experimenten ermittelt.
Zur Theorie des FA-Zentrums
Authors: Wille Hans
Published: February 2015

Im Anschluß an verschiedene Arbeiten*** über das F-Zentrum wird ein Modell des verwandten FA-Zentrums entworfen. Es geht von der Vorstellung aus, daß das Fremdion durch einen klassi­schen Polarisationsdipol beschrieben werden kann. Mit diesem Modell kann die Aufspaltung der Absorptionsbanden und der Dichroismus bei der Absorption quantitativ erklärt werden. Ebenfalls erhält man das Zusammenfallen der Emissionsbanden und eine qualitative Erklärung des leichten Dichroismus bei der Emission. Die Anpassung an das Experiment geschieht durch ein Yukawa -ähnliches Potential für die Lücke, das auf das F-Zentrum angewandt auch dort eine Anpassung erlaubt, die unmittelbare physikalische Bedeutung erhält. Durch Ankopplung des FA-Zentrums an Störschwingungen des Gitters gelingt es, die Halbwertsbreiten der Banden und dadurch diese selbst in guter Übereinstimmung mit dem Experiment zu berechnen.
Zur Kinetik der Ionenaustauscher. II. Die Film diffusion bei differentiellen Umbeladungen
Authors: Bunzl K . , Dickel G.
Published: February 2015

Im Konzentrationsbereich der Filmdiffusion wurde an Kunstharzionenaustauschern die Kinetik des Austausches für die Ionenpaare Wasserstoff- Kalium und Lithium -Kalium untersucht. Die theoretischen Betrachtungen mittels der Thermodynamik der irreversiblen Prozesse durch einen ternären Ansatz berücksichtigen sowohl das Diffusionspotential als auch die chemische Reaktion an der Austauscheroberfläche. Es wurden nur differentielle Umbeladungen durchgeführt, da dann Größen, wie der Gleichgewichtskoeffizient oder die Wasseradsorption, als konstant angesehen wer­ den können. Die Theorie erklärt alle experimentellen Ergebnisse quantitativ und die erhaltenen Diffusionskoeffizienten stimmen mit denjenigen, die man bei den entsprechenden ternären Elektrolytmischungen beobachtet, innerhalb der Fehlergrenze überein.
Si-Oberflächensperrschichtzähler in hohen Magnetfeldern bei 4,2 °K
Authors: Deimel P. , Rauch H.
Published: February 2015

A n-type silicon surface barrier detector was examined at 4,2 °K in longitudinal and transversal magnetic fields up to 60 kOe. Particularly in transversal magnetic fields and at low reverse bias a severe deterioration of resolution and an increase of pulse rise times is effected by the altered charge collection. The increased recombination probability results in a considerable loss of charge.
Nullstellenverteilung der großen kanonischen Verteilungsfunktion eines Gittergases in der Bethe-Approximation
Authors: Neumann H . P .
Published: February 2015

Es werden allgemeine Gleichungen zur Berechnung der Verteilung der Nullstellen von der großen kanonischen Verteilungsfunktion Ξ (y) eines Gittergases in der komplexen Ebene der Fugazität y in Bethescher Näherung angegeben, die nach einem graphischen Verfahren gelöst werden können. Für das zweidimensionale, quadratische Gitter und das dreidimensionale, kubische Gitter werden die Bestimmungsgleichungen für die Nullstellenverteilung mit Hilfe des graphischen Verfahrens explizit gelöst. Die Nullstellenverteilung von Ξ (y) des eindimensionalen Gittergases wird in ge­schlossener Form angegeben.
Zur Quantentheorie des elektrischen Restwiderstandes * I. Systeme kleiner Störstellendichte
Authors: Rauh A.
Published: February 2015

For the tensor of electrical conductivity of a crystal with static impurities a convergent series expansion is found in which the individual terms represent the multiple scattering of a quasi particle. The theory is suited to calculate quantum mechanically the residual resistance for both low and high concentration of impurities. For a small concentration and for free electrons the Boltzmann transport equation can be rigorously justified using the exact scattering cross section for the transition probability in the collision term rather than the cross section in the Born approximation.
The Thermal Content of Quantum States
Authors: Gilson J. G.
Published: February 2015

It is shown that the exact structure of Schrödinger Quantum Mechanics is a consequence of the assumption that there exist two subquantum fluids in local thermal equilibrium.
Statistical Foundations of Thermodynamics I. Asymptotic Form of the Frequency Functions
Authors: Still E. , Haubold K. , Münster A.
Published: February 2015

It is shown that, for all conceivable ensembles of statistical thermodynamics, at the thermodynamic limit, the frequency function of the fluctuations of macroscopic extensive parameters equals a Gaussian. The proof is based on a generalisation of Khinchin's method using the concept of "smoothed frequency functions."
Zahl und Auswahl der Lösungen der Kraftkonstantenmatrix unter Verwendung von Isotopenfrequenzen
Authors: Fadini A.
Published: February 2015

Für die Berechnung der Zahl z der Lösungen der Kraftkonstantenmatrix F sym aus den Schwingungsfrequenzen des Moleküls und aus j Isotopenfrequenzsätzen von j isotopen Molekülen unveränderter Symmetrie erhält man bei gegebener algebraischer Unabhängigkeit des Gleichungssystems der n(n + 1) /2 Gleichungen (u.a. bei Einhaltung der Produktregel) als untere Grenze der Lösungen

z(Fsym, Isot., n = 2 , 4 , 6 , . . . ) = n ! (n - 1 ) ! n/2 mit j = n/2 ,

z(Fsym, Isot., n = 3, 5, 7, .. .) = (n - 1) !3-(n - 2) ! (n-3)/2 mit j= ( n + 1)/2 ,

die für inverse Eigenwertprobleme bis zur Ordnung n = 10 in einer Tabelle zahlenmäßig dargestellt werden. Zur Aussonderung weniger Lösungen oder nur einer Lösung aus der für n≧ 4 praktisch nicht mehr berechenbaren Mannigfaltigkeit werden Auswahlregeln angegeben, die auf der Realität der Kraftkonstanten, der Heranziehung weiterer Isotopendaten, der Zuordnung zu den charakteristischen Frequenzen, einer mathematischen Grenzwertbeziehung, der Bevorzugung kleiner Kopplungsglieder und einer Reduktion des Eigenwertproblems beruhen.
Experimentelle Untersuchung der Entstehung und Beschleunigung der stromführenden Schicht in einer Z-Pinch-Entladung
Authors: Kleist G. , Bötticher W. , Dammann H. , Kogelschatz U.
Published: February 2015

The formation and acceleration of the luminescent current layer in a z pinch discharge (diameter 44 cm, electrode distance 9 cm) has been investigated. From observations of discharges in different gases with filling densities in the range 2.2·1O-7 ≦ ϱ0 ≦ 6.6 · 10 -6 g/cm3 a model has been developed for the different structures of the contracting layer. The essential discharge parameters are the density and the eletctron mean free path in the cold gas.
The Dissociation Constants of some Phosphorus(V) Acids
Authors: Peacock C.J. , Nickless G.
Published: February 2015

The dissociation constants of ortho-, monothio-, monoamido- and diamido-phosphoric acids have been measured at a series of temperatures using a potentiometric titration method involving com­puter fitting of the theoretical titration curve to the experimental one, the constants being used as adjustable parameters. Less accurate values for diamidothio- and tetrathio-phosphoric acids were also obtained.

The results are discussed with respect to the site of protonation. For the monothio acid only the first dissociation (K1) appears to involve the sulphur atom. The monoamido compound may be protonated first on nitrogen (K2). The diamido- and diamidothio-phosphoric acids show a remark­able effect in that, although monoanionic, two p Ka values may be measured, the first protonation (K2) being probably onto nitrogen, the second (K1) involving the oxygen atom more.
On some Properties of the Schrauben Functions in Connection with the Magnetic Operators
Authors: Jannussis A. D. , Tsilimigras P. I.
Published: February 2015

In this paper we introduce two new "magnetic" operators and we show that these are the creation and annihilation operators of the schrauben functions. The schrauben functions are the eigenfunctions of the Hamilton operator describing a free electron under the action of a uniform magnetic field. By transforming these two operators we obtain two other operators which we show to be of Harpers type, as was expected.
Untersuchung der Ionenumladung bei Gasentladungen in N2 — O2-Gemischen
Authors: Römling Horst
Published: February 2015

Abstract Ionic Charge Exchange in Gas Discharges in N2 - O2-Mixtures. - The charge exchange reaction N2
+ + O2→N2+O2
+ influences the ion current of pulsed Townsend discharges in N2 - O2-mixtures. This influence is investigated in mixtures with 1 . . . 20% oxygen at reduced electric fields from 100 to 500 V/cm Torr in a range of total pressure from 1 to 10 Torr. A least squares fit of the theoretical ion currents to the experimental ones allows to determine drift velocities of O2
+ -ions in the mixtures and rate constants of the charge exchange reaction.
On Non-Ideal Conditions in Plane Source Diffusion Experiments
Authors: Wallin Lars-Erik , Gustafsson Silas E .
Published: February 2015

The concentration in bottom layer diffusion experiments with non-ideal initial conditions is ex­ pressed as an infinite series, the first term of which represents the ideal distribution. It is shown that it is always possible to define the zero time in such a way that the approximation of the diffusion process to an ideal one is optimized.
Anwendung der von Straubel modifizierten Millikan-Anordnung zur Messung der Photo- Ionisationsschwellen von Kristallen
Authors: Gerischer H. , Ranke W.
Published: February 2015

An improved photoelectric method has been developed for determining the ionization potential of crystals. Results are reported for pyrene, perylene, 1,2-benz-anthracene and rhodamin-B.
Die Propagatormethode in der Gitterraumtheorie
Authors: Weidemann Erich G.
Published: February 2015

Keywords

The Feynman diagrams and rules of a field theory with local four fermion coupling are transformed into a theory of interacting fermions in a finite dimensional Hilbert space constructed on Z3 points of a cubic lattice. The propagator is derived for the lattice space theory and the formal similarity and the qualitative differences are discussed and compared with conventional field theories. The mass produced by the interaction is calculated by compensation of the first order self-energy diagrams (Hartree-Fock-approximation). The solution for coupling constant W > 0 violates the chiral symmetry, the solution for W < 0 the cubic symmetry of the theory. The second order corrections to the mass operator are calculated. They diverge in the limit Z→∞ like

if W is proportional to

which is necessary for a finite mass in the HFapproximation. Under the same assumption the maximum divergence is like

in any order of the perturbation theory. The mass operator is finite including second order contributions if W is proportional to

. In this case the higher order contributions decrease like

.
Non Radiative Electronic Transitions in Ionic Crystals I* Crystal model and calculation of states
Authors: Löffler Alf
Published: February 2015

The theory of non radiative electronic transitions is represented in two papers. In the first of these we calculate wavefunctions, energies, matrix-elements etc. In the second we discuss the general reaction mechanism and apply the theory to two examples. The wavefunction of a crystal volume containing one defect is calculated on the base of a microscopic theory. For our numerical discussion we used as an example an anion vacancy in MgO, LiF, NaCI, NaBr, KC1, KBr, KJ. The results are collected in Table 1 and 2. As far as experimental data have been available they agree completely with our results.
Non Radiative Electronic Transitions in Ionic Crystals II* Reaction Formalism and Results
Authors: Löffler Alf
Published: February 2015

A general formalism to describe radiationless electronic decay (RED) is developed. Two con­ditions are derived that must be fulfilled to make RED possible. Using the data derived in part I of this paper the general formulae are applied to a F-center in KCl and MgO. In KC1 th e con­ditions for RED are not fulfilled while in MgO RED proves to be more probable th an radiative decay. This is in complete agreem ent w ith experim ental knowledge.
Higher Harmonics Generation in Weakly Ionized Plasmas in Time-Varying Crossed Fields
Authors: Stiller Wolfgang , Vojta Günter
Published: February 2015

The linearized Boltzmann equation of kinetic theory for the electrons of a weakly ionized plasma under the action of an alternating electric field E = cos ω t {Ex, Ey, Ez} and a circularly polarized magnetic field BR = B {cos ωBt, sin ωbt, 0} is solved. The direction-dependent part f1 (r, v, t) of the distribution function contains especially higher harmonics with frequencies 2 ωB, ω± ωB , ω±2ωB. These overtone frequencies are generated - unlike the higher harmonics obtained by Margenau and Hartman - by a cross drift mechanism and are present even if the isotropic part f0 of the electron distribution function is assumed to be time-independent. The physical meaning of the various contributions to the distribution function f1 is discussed in detail.
Generalized Electron Cyclotron Resonance in Weakly Ionized Time-Varying Magnetoplasmas
Authors: Stiller Wolfgang , Vojta Günter
Published: February 2015

The electron distribution function is calculated explicitly for a weakly ionized plasma under the action of an alternating electric field E = {0 , 0 , Eoz cos ω t} and a circularly polarized magnetic field BR = Bc{cos ωB t, sin ωB t, 0} rotating perpendicular to the a.c. field. Furthermore, a constant magnetic field B0 = {0, 0, B0} is taken into account. The isotropic part f0 of the electron distribution function which contains, in special cases, well-known standard distributions (distributions of Druyvensteyn, Davydov, Margenau, Allis, Fain, Gurevic) shows a resonance behaviour if the frequencies ω, ωc = (q/m) Bc , ω0 = (q/m) B0 , and ωB satisfy the relation

ω=

This can be understood as a generalized cyclotron resonance phenomenon.
Magnetische Relaxation durch Translationsdiffusion in Flüssigkeiten
Authors: Krüger Gottfried J.
Published: February 2015

The general theory of Torrey for magnetic relaxation by isotropic translational diffusion has been applied to investigations of nuclear and electronic relaxation in liquids. The theory leads to a general correlation time

(d distance of closest approach of interacting spins,  mean square flight path. D diffusion constant).

It could be shown that the theoretical model fits the experimental data obtained in organic solutions of free radicals. The correlation times of dimethoxyethane and toluene exhibit activation energies of 3.0 and 3.1 keal/mole respectively at high temperature. Dimethoxyethane corresponds to the limiting case of the random flight theory where  « d2, whereas Tn toluene  ≈ d2 is obtained.
Quadrupoleffekte der magnetischen Kernresonanz an 11B in Bor-Stickstoffverbindungen
Authors: Wiedemann Klaus , Voitländer Jürgen
Published: February 2015

First and second-order quadrupole effects of the 11B nuclear magnetic resonance have been measured in polycrystalline samples of dimere dimethylaminoboranes and tetramethylboracene. With the theory of powder patterns for first and second-order quadrupole interaction the nuclear quadrupole coupling constants e2 q Q/h and asymmetry parameters η of 11B have been determined. For these measurements boron-free inserts had to be constructed for the probes of the Varian Wide Line Spectrometer DA 60.
Zerstörung der Fernordnung in festem Sauerstoff durch Fremdatome
Authors: Bostanjoglo O. , Goertz C.
Published: February 2015

The hexagonal lattice constants a, c of β-O2 and Ar/β-O2 mixtures were measured in the range 32 ... 4 °K by electron diffraction. A sharp maximum of c accompanied w ith a sudden decrease of the mean crystal size by more than an order of magnitude at 18 °K was found for im pure β-O2. The transform ation β-O2 → "am orphous" O2 which takes place on electronirradiation of β-O2 below 17 °K may therefore be simply a breaking up of the impure O2-crystals into tiny pure crystals caused by mechanical stress due to built in foreign molecules.
Photoinduzierte Stoßprozesse metastabiler Wasserstoffatome mit H2 im Energiebereich von 0,05 — 0,47 eV
Authors: Comes F. J. , Wenning U.
Published: February 2015

Molecular hydrogen was excited by selective absorption of ultraviolet radiation of appropriate wavelength into the vibrational levels ν′ 3, 4, and 5 of the electronic D (1IIu)-state. For the radiation bandwidth chosen the molecule was only formed in the rotational levels J = 1 and 2 of the R-branch. The excited molecules decay by predissociation into two hydrogen atoms of translational energy which is equal to one half of the difference between the excitation and dissociation energies. One of the atoms is formed in its first excited state. The formation of the excited species can be proven by its fluorescence (Lymanα-radiation).

As a result the measurements show, that the excited atoms are all in the metastable 2S-state and not in the short-lived 2P -state. Without electric fields these metastable atom s loose their excitation energy in collisions with the surrounding hydrogen molecules. One part (a) follows an induced transition to the electronic ground state by the emission of Lyα-radiation (1216 Å), the other part (b) is transformed to products or undergoes an energy transfer process without emitting Lyα-radiation.

If a quenching field is applied spontaneous emission will compete with collisional deactivation, which allows the deactivation cross sections to be calculated. These cross sections are between 50 and 100 Å2 (a) and about 50 Å2 in case (b). In case (a) the collision cross section increases with the velocity of the particles whereas in case (b) a constant value was found.
Magnetic Susceptibility Studies and Possible Ground State Crystal Field Splitting of Two Organometallic Neptunium(IV) Complexes
Authors: Fischer R. D. , Laubereac P.
Published: February 2015

Extensive paramagnetic susceptibility studies between liquid helium and room temperature have been carried out on polycrystalline samples of the two organometallic Np(IV)-complexes Np(C5H5)4 and (C5H5)3NpCl. From a combined interpretation of the corresponding 1/Xm-vs-T-and μ2
eff-vs-T-curves, respectively, is suggested that, in accordance with the tetrahedral molecular symmetry to be assumed for Xp(C5H5)4, a cubic Τ8 crystal field level should lie lowest in this compound. The zero field splitting is apparentlv smaller th an 5 cm-1.
Die elektrischen Transportgrößen von p-und n-Zn05Cd0,5Sb
Authors: Ahlgrimm H. -J. , Schneider G.
Published: February 2015

Es wurden Mischkristalle der Zusammensetzung Zn0.5Cd0.5Sb durch Zonenschmelzen hergestellt. Die so erhaltenen und durch In-Dotierung n-leitenden Proben erwiesen sich in den elektrischen Eigenschaften als wesentlich stabiler als polykristallines Material, was auf eine Beteili­gung von Korngrenzen bei den n-p-Umwandlungserscheinungen dieser Mischkristalle hindeutet. Nun möglich gewordene Messungen der elektrischen Transportgrößen (elektrische Leitfähigkeit, Hall-Effekt, Thermokraft, transversaler Nernst-Ettingshausen-Effekt) in Abhängigkeit von der Temperatur ergaben, daß bei Zimmertemperatur n-leitende Proben bei tiefen Temperaturen p-Leitung zeigen. Die Ergebnisse werden diskutiert.
Microwave Rotational Spectrum of Indium Monofluoride
Authors: Lovas F. J. , Törring T.
Published: February 2015

The rotational transitions J = 1 → 2 and 2 → 3 were measured in 115In19F. From these spectra the following molecular parameters have been determined: the Dunham-coefficients Y01, Y11 and Y02, the quadrupole coupling constants, eqQ, in the ν = 0 and v = 1 vibrational states as well as the spin-rotation coupling constant cIn.
Tentatively Standardized Symmetry Coordinates for Vibrations of Polyatomic Molecules Part III. Symmetrical X2Y4 Models, with some Related WX2Y4 and W2X2Y4
Authors: Cyvin B. N. , Cyvin S. J. , Hagen G. , Elvebredd I. , Brünvoll J.
Published: February 2015

A theoretic treatment is given for the planar ethylene-like (D2h) model, the corresponding twisted (right-angled) model (D2d), and the general case of D2 symmetry. The correlations between the various symmetry species which pertain to the molecular vibrations of the considered models are explained. Complete sets of symmetry coordinates are proposed. The G matrix is given for the general D2 model. Also the various types of Coriolis couplings are discussed, including the relationships between Cα elements involving the degenerate a and b species in the twisted (D0) model. Some of the most im portant Cα elements are listed.

Sets of symmetry coordinates are also given for the allene (D2d) and butatriene (D2h) type models.
Fallout aus chinesischen Kernwaffenversuchen
Authors: Fahland J.
Published: February 2015

Short-lived radionuclides have been measured in fallout of Chinese nuclear tests. The measured yield ratios of the nuclides 95Zr, 111Ag, 115Cd, 156Eu, 237U and 239Np have been corrected for fractionation effects and compared to calculated ratios. Free parameters of the calculation such as most frequent neutron energy, time integrated neutron flux, and fission material were ad­justed by means of a least square criterion. For the tests 2, 3, 5 and 7 the most frequent neutron energy was found to be 5 keV. The corresponding Maxwellian neutron fluxes were within 1021 and 1024 n/cm2. In addition, 14-MeV neutron fluxes within 1019 and 1022 n/cm2 had to be assumed. The analysis yields as average of the converted fission material a mixture of 235U and 238U with 7-99% of 235U. - The fractionation of 140Ba in surface bursts corresponded to that in air bursts.
Mathematische Modelle für reaktionskinetische Phänomene
Authors: Heckmann K. , Vollmerhaus W. , Kutschera J. , Vollmerhaus E.
Published: February 2015

The theoretical treatment of a number of stationary kinetic phenomena requires the solution of a system of linear equations. An algorithm is described which enables an algebraic solution to be found by means of a digital computer using probably a minimum length of calculation time. This algorithm is derived mainly from arguments based on the theory of graphs; its essential feature is the use of numerical operations on the indices of the coefficients of the equations. The algorithm is illustrated in terms of a special model of the membrane.
Theory of Creeping Waves in Acoustics and Their Experimental Demonstration
Authors: Neubauer W. G. , Uginčius P. , Überall H.
Published: February 2015

The theory of creeping waves is developed by applying the Sommerfeld-Watson transformation on the normal-mode solution for acoustic scattering from an infinite elastic cylinder. Two types of radiating, circumferential waves emerge: (1) highly attenuated ‘‘Franz-type” waves with subsonic speeds, and (2) supersonic ‘‘Rayleigh-type” waves which arc only slightly attenuated. The experimental study of these waves for an aluminium cylinder is accomplished by two in­dependent methods: (f) time measurements of sequential pulses, and (2) direct visualization by Schlieren techniques. Measured velocities, attenuations, critical angles, and scattering cross sections are compared with theoretical calculations.
On the Problem of Closure Conditions in Particular for Vlasov Turbulence
Authors: Max-Planck-Institut für Physik und Astrophysik, München Pitter
Published: February 2015

In turbulence-theory, the equations for the dynamics of statistical quantities usually form an infinite system. The coupled momentum equations are the best known example. Such relations can also be derived for the n-point-distribution functions which describe the stochastic state of a tur bulent medium at every instant. This will be shown for the case of Vlasov turbulence. In order to obtatin a solution, it is a common procedure, to terminate such infinite systems of equations by closure-conditions. Often this is considered as an approximation. In the case of Vlasov-turbulence it can be shown that a wide variety of closure conditions, all of which are exactly admissible, exists.
Über linear passive Transformationen stochastischer Prozesse. II.
Authors: Keller J.
Published: February 2015

In this paper some further results in the theory of Linear Passive Transformations (LPT) of stochastic Processes will be given, among them a theorem on the LPT of the characteristic functional of the input-process which allows one under certain conditions to get the probability -distributions of the output-process. The theory is generalized to vector-valued stochastic processes and to processes defined by means of distributions.
Höhere Bornsche Näherungen für die elastische Streuung von Elektronen an Atomen Higher Born Approximations for Elastic Electron Scattering from Atoms
Authors: Dudenhausen Wolf-Dieter
Published: February 2015

Higher Born Approximations for Elastic Electron Scattering from Atoms. A theorem analogous to the unitarity relation by Glauber and Schomaker is derived for Born’s approximations. For a given potential Φ (r) =μ (ħ2/2 m) V (r) of the scattering atom the n-th approximation fn for the scattering amplitude is defined as the function resulting from the n-th iterative step of Born’s approximation.| If | fn |2 is expanded into a series of powers of the parameter μ, this series up to terms in μn+1 is defined as the n-th approximation for the differential cross section dσn/dΩ, and not |fn|2 itself. In this case an extension of the optical theorem Im fn+1 (0) = (k/4π) σn can be derived.

For a potential Φ(r)=-(Z e2/4π ε0 r)·exp(-r/R) ∑ airi exact analytic expressions for the scattering amplitude fn and the differential cross section dσn/dΩ can be given in first and second Born approximations.

An important example is the hydrogen-like atomic potential in which, in contradistinction to Wentzel’s model, the electron density σ(r) is limited even for r → 0. For this model, the differential scattering cross section in second Born approximation exceeds the values of the first approximation for all scattering angles, while experimental data indicate a correction of the opposite sign. An estimate of the cross sections in third approximation shows that they are again below’ the first approximation. These results indicate that the Born’s first approximation is not only less complicated but even more accurate than the second one. The absolute values of the scattering amplitudes in first and second approximations diverge considerably even at high energies, mainly due to the imaginary part Im f2(ϑ) of /2(ϑ). Therefore, conclusions on the phase η(ϑ) from Im f2(ϑ) do not seem to be reliable.
Anreicherung der schweren Kohlenstoff-Isotope durch Gegenstromelektrolyse (IX. Mitt. über Gegenstromelektrolyse)
Authors: Thiemann W.
Published: February 2015

The isotope effect of C-14 on the electromigration properties of formate, oxalate, and methylammonium ions has been investigated, using a counter-current electromigration column as described in previous papers. The isotope effect depends on the composition and concentration of the electrolyte and varies between 0.001 and 0.009. Obviously, it is a superposition of kinetic and equilibrium isotope effects. Some consequences on the mechanism of isotope effects of molecular ions are discussed.
Notizen: Über die Ursache der Supraleitung; II
Authors: Krebs H.
Published: February 2015

The assumption that superconductivity can occur if the electrons can move without crossing atomic nodal surfaces is confirmed by some more examples. In compounds as CuRh2S4 (spinel structure) and CuS2 (pyrite structure) per formula unit one s electron is missing to a stabtle electron configura­ tion. The high pressure modifications of Se and Te possess one 5s resp. one 6s electron per atom.

InC8K, LiBi, and NaBi pz orbitals of C resp. Bi and s or­bitals of the alkali atoms form layers without nodal surfaces.

In the hexagonal and tetragonal tungsten bronzes there exist channels containing molecular orbitals without nodal surfaces. In the cases mentioned last the superconductivity is expected to be highly anisotropic.
Root Mean Square Charge Radii of 12C, 14N and 16O
Authors: Bentz Hans Alfred
Published: February 2015

From elastic electron scattering between 30 and 60 MeV, the following essentially model independent rms charge radii (fm) have been deduced: 2.395 + 0.028 (12C) ; 2.492 + 0.033 (14N) ;2.666± 0.033 (16O). An improved value for 9Be is (2.43 ±0.08) fm.
The Temperature Dependence of the Isotope Effect for Electromigration of Lithium Ions in Molten Lithium Nitrate
Authors: Lundén Arnold , Ekhed Alf
Published: February 2015

The relative difference (Δb/b) between the internal electromigration mobilities of 6Li and 7Li in molten LiNO3 has been measured over the range 313° to 488 0C. The mass effect,μ =(Δb/b) /(Δm/m), is found to be

μ = 0.0845+ (0.00002 ±0.00002) (t-300) where t is the temperature in °C and the quoted error is the standard deviation. There is thus in this case no significant influence of the temperature upon the mass effect. Some previous investiga­tions of molten LiNO3 gave smaller values for the mass effect. The reasons for these apparent dis­crepancies are discussed. A slight, but significant, anomalous enrichment of the light isotope is ob­tained in the middle of the cell, as has been previously observed in experiments with KNO3 .

The mass effects have now been measured for all five alkali ions in the pure molten nitrates. For a corresponding temperature chosen 5% above the melting point none of the experimental values differ more than 14% from the relation

μ+ =-0.0848 (1+m +/46) -1.

The obtained relations are interpreted in terms of cooperative motion of the ions in a molten salt.
Magnetische Widerstandsänderung von Kupfer-und Silber-Einkristallen
Authors: Neubert W. , Neubert W.
Published: February 2015

Magnetoresistance measurements of Copper and Silver single crystals in weak magnetic fields at 4.2 K are reported. In addition, the magnetosresistance has been calculated. The model used is based on ROAF's analytical representation of the Fermi surface. In view of the simplifying as­ sumptions made about bandstructure and scattering mechanism, the experimental data are found to agree reasonably well with the results of the numerical calculations.