bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical Evaluation of the Supraosseous Gingivae Before and After Crown Lengthening
Authors: Perez José R. , Smukler Hyman , Nunn Martha E.
Published: May 2007

Background: Despite the broad use of crown‐lengthening surgery (CLS), there is no complete agreement as to the desired amount of exposed sound tooth structure needed to accommodate both the restorative needs and the reformation of the supraosseous gingiva (SOG). Classically, it has been proposed that ∼3 mm of SOG, the amount considered by most to be present before surgery, will be reformed after CLS. The purpose of this study was to test the viability of transsulcular probing (TSP) and to determine whether the SOG that forms after CLS is the same as that measured preoperatively.

Methods: Nineteen patients underwent CLS with the surgical tooth acting both as the control and the test site. The SOG dimension was measured by TSP before and 6 months after surgery. Stents were used as fixed reference points. Intraclass correlations were calculated to test for the reliability of TSP measurements versus direct‐bone‐level (DBL) measurements. A Wilcoxon signed‐rank test was used to compare the means for the mean buccal, mean lingual, and overall mean SOG dimensions at baseline to corresponding measurements at 6 months.

Results: Intraclass correlation coefficients for TSP measures of SOG to DBL measures of SOG ranged from 83.4% agreement to 91.9% agreement, with all correlations being highly significant (P <0.001), indicating a high degree of agreement between TSP and DBL. The differences in SOG dimensions, 6 months after surgery compared to baseline, were as follows: mean buccal, 0.51 mm; mean lingual/palatal, 0.61 mm; overall mean, 0.56 mm. These differences were significant for all three comparisons (P <0.001, P <0.004, and P <0.001, respectively).

Conclusions: TSP is an accurate alternative method to DBL in clinically determining SOG dimensions. Six months after CLS, the SOG dimension was reduced by 0.51 to 0.61 mm compared to the presurgical measurement, with these mean differences being statistically significant.
Marijuana Initiation in 2 American Indian Reservation Communities: Comparison With a National Sample
Authors: Whitesell Nancy Rumbaugh , Beals Janette , Mitchell Christina M. , Novins Douglas K. , Spicer Paul , O’Connell Joan , Manson Spero M.
Published: May 2007

Objectives. We examined disparities in age-related patterns of marijuana initiation in 2 culturally distinct American Indian reservation communities (from the Northern Plains and the Southwest) compared with a national sample.

Methods. We used discrete-time survival models to estimate age-related risk for initiation with data from 2 population-based studies: the American Indian Service Utilization, Psychiatric Epidemiology, Risk and Protective Factors Project and the baseline National Comorbidity Survey.

Results. Among respondents who were born before 1960, peak risk for marijuana initiation in all samples was at age 18 years, and risk was greatest in the national sample. Among those who were born later than 1960, risk peaked at age 16 years and was highest in the American Indian samples. Males were at increased risk compared with females, especially in the older cohort and the Southwest tribal sample.

Conclusions. Findings of disproportionate risk for marijuana initiation among younger members of the tribal samples raise concerns that American Indian reservation youths may be increasingly vulnerable to drug use and its concomitants, which suggests a need for more aggressive prevention efforts in these communities.
A Nationwide Study of Discrimination and Chronic Health Conditions Among Asian Americans
Authors: Gee Gilbert C. , Spencer Michael S. , Chen Juan , Takeuchi David
Published: May 2007

Objectives. We examined whether self-reported everyday discrimination was associated with chronic health conditions among a nationally representative sample of Asian Americans.

Methods. Data were from the Asian American subsample (n = 2095) of the National Latino and Asian American Study conducted in 2002 and 2003. Regression techniques (negative binomial and logistic) were used to examine the association between discrimination and chronic health conditions. Analyses were conducted for the entire sample and 3 Asian subgroups (Chinese, Vietnamese, and Filipino).

Results. Reports of everyday discrimination were associated with many chronic conditions, after we controlled for age, gender, region, per capita income, education, employment, and social desirability bias. Discrimination was also associated with indicators of heart disease, pain, and respiratory illnesses. There were some differences by Asian subgroup.

Conclusions. Everyday discrimination may contribute to stress experienced by racial/ethnic minorities and could lead to chronic illness.
Hispanic Paradox in Biological Risk Profiles
Authors: Crimmins Eileen M. , Kim Jung Ki , Alley Dawn E. , Karlamangla Arun , Seeman Teresa
Published: May 2007

Objectives. We examined biological risk profiles by race, ethnicity, and nativity to evaluate evidence for a Hispanic paradox in measured health indicators.

Methods. We used data on adults aged 40 years and older (n = 4206) from the National Health and Nutrition Examination Surveys (1999–2002) to compare blood pressure, metabolic, and inflammatory risk profiles for Whites, Blacks, US-born and foreign-born Hispanics, and Hispanics of Mexican origin. We controlled for age, gender, and socioeconomic status.

Results. Hispanics have more risk factors above clinical risk levels than do Whites but fewer than Blacks. Differences between Hispanics and Whites disappeared after we controlled for socioeconomic status, but results differed by nativity. After we controlled for socioeconomic status, the differences between foreign-born Hispanics and Whites were eliminated, but US-born Mexican Americans still had higher biological risk scores than did both Whites and foreign-born Mexican Americans.

Conclusions. There is no Hispanic paradox in biological risk profiles. However, our finding that foreign-born Hispanics and Whites had similar biological risk profiles, but US-born Mexican Americans had higher risk, was consistent with hypothesized effects of migrant health selectivity (healthy people in-migrating and unhealthy people out-migrating) as well as some differences in health behaviors between US-born and foreign-born Hispanics.
Persistent Clusters of Mortality in the United States
Authors: Cossman Jeralynn Sittig , Cossman Ronald E. , James Wesley L. , Campbell Carol R. , Blanchard Troy C. , Cosby Arthur G.
Published: May 2007

We explored how place shapes mortality by examining 35 consecutive years of US mortality data. Mapping age-adjusted county mortality rates showed both persistent temporal and spatial clustering of high and low mortality rates. Counties with high mortality rates and counties with low mortality rates both experienced younger population out-migration, had economic decline, and were predominantly rural. These mortality patterns have important implications for proper research model specification and for health resource allocation policies.
Mortality of Foreign-Born and US-Born Hispanic Adults at Younger Ages: A Reexamination of Recent Patterns
Authors: Eschbach Karl , Stimpson Jim P. , Kuo Yong-Fang , Goodwin James S.
Published: May 2007

Objectives. We sought to determine whether mortality rates among immigrant and US-born Hispanic young adults were higher or lower compared with non-Hispanic Whites. We also sought to identify which causes of death accounted for the differences in mortality rates between groups.

Measures. We used Texas and California vital registration data from 1999 to 2001 linked to 2000 census denominators. We calculated cause-specific, indirectly standardized rates and ratios and determined excess/deficit calculations comparing mortality rates among US- and foreign-born Hispanic men and women with rates among non-Hispanic White men and women.

Results. Mortality rates were substantially lower among Hispanic immigrant men (standardized mortality ratio [SMR]=0.79) and women (SMR=0.59) than among non-Hispanic White men and women. Most social and behavioral and chronic disease causes in Texas and California other than homicide were noteworthy contributors to this pattern. Mortality rates among US-born Hispanics were similar to or exceeded those among non-Hispanic Whites (male SMR=1.17, female SMR=0.91).

Conclusions. Mortality rates among younger Hispanic immigrants in Texas and California were lower than rates among non-Hispanic Whites. This pattern was not observed among US-born Hispanics, however.
Electromagnetic Interaction of Leptons in the Theory of United Space
Authors: Bich Nguyen Duc , van Phi Duong
Published: May 2007

In this paper we calculate some effective cross‐sections of leptons on the basis of S‐matrix constructed in 8‐dimensional united space [1]. The Lagrangian is chosen, within the framework of the 0 (71) group classification of elementary particles. Electromagnetic interaction does not change the internal structure of the participating particles. The results obtained agree well with experiments.
Eine nichtlineare lorentzinvariante Gravitationstheorie
Authors: Petry W.
Published: May 2007

Eine nichtlineare Lorentz‐invariante Gravitationstheorie und eine Lorentz‐invariante Hamilton‐Funktion für ein Teilchen mit Spin im Gravitationsfeld werden aufgestellt. Die Bewegungsgleichungen werden studiert. Die Theorie wird auf die drei bekannten Effekte der Allgemeinen Relativitätstheorie angewandt. Für die Rotverschiebung der Spektrallinien und die Lichtablenkung am Sonnenrand erhält man dieselben Resultate wie in der Allgemeinen Relativitätstheorie, während die Theorie für die Perihelbewegung des Merkur 40,3″ ergibt, was in guter Übereinstimmung mit den experimentellen Ergebnissen von DICKE ist.
Bemerkungen zur Teilchenerzeugung im expandierenden Universum
Authors: Kreisel E.
Published: May 2007

Es wird gezeigt, daß man spontane Teilchenerzeugung im leeren Minkowski‐Raum beschreiben kann, wenn man Teilchenzahloperator und Hilbertraum in ähnlicher Weise definiert, wie in Arbeiten über Teilchenerzeugung im expandierenden Universum [1–3].

Dementsprechend rührt diese spontane Teilchenerzeugung nicht vom Gravitationsfeld her, sondern hängt mit der Nichteindeutigkeit des Teilchenbegriffs und der Auswahl eines zeitabhängigen Teilchenzahloperators zusammen.
On the Gravitational Collapse in Relativistic Theories of Gravitation
Authors: v. Borzeszkowski H.‐H.
Published: May 2007

Following Einstein, we consider a simple model of a star, namely a spherically symmetric distribution of particles which are all moving along circular orbits around the center of the particle cluster. According to arguments given by Einstein, Laue, Treder and others, the existence of stationary circular motions for all values of r can be considered as a necessary condition for all collapse‐free relativistic (classical) theory o gravitation. The discussion shows that, assuming the validity of the weak principle of equivalence and the principle of causality, one has to consider theories with a g00‐function different from the Einstein‐Schwarzschild one. We discuss some g00 types and show that our point of view leads in the direction of gravitational equations with a cut‐off length.
Die Anwendung relativistisch bewegter Bezugssysteme in der Elektrodynamik
Authors: Guzunajew Z. I. , Kasatschkow W. D. , Terlezkij J. P.
Published: May 2007

In der Arbeit wird eine Methode des Übergangs vom Inertialbezugssystem zu relativistisch bewegten Systemen dargelegt. Die hergeleiteten Transformationsformeln werden zur Lösung einiger Aufgaben der Elektrodynamik benutzt.
Isobaric Analogue State of the 341 KeV Level of Mn56 and Fe56
Authors: El‐Kazzaz S. A. , El‐Nadi L. M.
Published: May 2007

When Mn55 is bombarded by protons, a proton capture resonance is detected at Ep = (1678 ± 4) KeV. The spectral and angular distribution studies of the (p, γ) and (p, p) reactions at this resonance have established Jπ = 3+, lp, = 1, Γp = (1 = 0.2) KeV and Γ = 17 KeV for the energy level at (11836 ± 4) KeV in the Fe56 nucleus. Comparison of the present results with those obtained by (n, γ) and (d, p) reactions on the Mn55 nucleus suggests that this resonance state is most probably the isobaric analogue of one member of the doublet at 341 KeV in the Mn56 nucleus.
Causality in Weisskopf‐Wigner Type Theories
Authors: Mühlstein J. , Ernst V.
Published: May 2007

It is shown that the essential requirements of causality are met already in the “lowest orders” of the systematic “Weisskopf‐Wigner approximation scheme” introduced recently.
Stoßbestimmte Relaxation des Elektronenensembles im Plasma bei zusätzlicher Aufheizung durch ein elektrisches Feld I. Die charakteristischen Zeiten für den Übergang in stationäre Zustände
Authors: Wilhelm J. , Winkler R.
Published: May 2007

Ausgehend von der zeitabhängigen Boltzmann‐Gleichung für die Elektronen wird die Zeitentwicklung der Isotropverteilung und der hieraus folgenden makroskopischen Größen, mittlere Energie, Beweglichkeit, Anregungsfrequenz und Energieübertragungsquotienten beim Übergang zwischen zwei stationären Plasmazuständen bestimmt. Dabei beziehen sich die Rechnungen auf ein schwach ionisiertes Neon‐Plasma im Parameterbereich typischer Nieder‐ und Mitteldruckentladungen.

Im Resultat dieser Untersuchungen werden Aussagen über die sich um Größenordnungen unterscheidenden charakteristischen Einstellzeiten im Relaxationsprozeß und über ihre Abhängigkeit von den energetischen Ausgleichsprozessen erhalten. Als geeignete Größen zur Charakterisierung der Einstellzeit unter gegebener Parametersituation erweisen sich hierbei die Energieübertragungsquotienten für den Energieverlust über die berücksichtigten Stoßprozesse.
Sea Level Muon Spectrum Derived from Bugaev Model
Authors: Bhattacharyya D. P.
Published: May 2007

The pion and kaon spectra in the atmosphere are derived from primary nucleon spectrum determined by GRIGOROV et al.; they satisfy the relations N(Eπ) dEπ = 0.187 EdEπ and N(Ek) dEk = 0.017 E dEk, respectively. By using the pion‐kaon atmospheric diffusion equation the sea level muon spectrum is calculated and the result compared with the magnetic spectrograph data of ALLKOFER et al. and AYRE et al.
Solitons in Stimulated Raman Scattering
Authors: Steudel H.
Published: May 2007

The semiclassical equations of SRS are derived by the following method: The many‐level molecule is described by the Schrödinger equation and subsequently all amplitudes but those of the essential two levels are eliminated by approximate integration.

Especially the case of equal group velocities for pump and Stokes wave is considered. Terms describing a frequency shift due to dynamical Stark effect and a change of refraction index by vibrational excitation can be removed by a suitable transformation.

Under various, physically different, assumptions the system of molecular and field equations is reduced to the equations describing a quasimonochromatic pulse propagating in a resonant two‐level system, and in this way we can find a rich manifold of solutions. E.g., the 2π‐pulse of self‐induced transparency can be transferred to SRS. By other assumptions we are led to equations defining the Bäcklund transformation for the sine‐Gordon equation. For this case also soliton type solutions can be constructed.
Renormalized Perturbation Expansion in Kinetic Theory
Authors: Der R.
Published: May 2007

Ladder summation techniques are applied to the recently developed c‐number diagram expansion for kinetic equations describing the relaxation of quantum fluids. By way of the resummation, the kinetic equations are reformulated in terms of a T‐matrix which describes the scattering of two particles influenced by the remaining particles of the system via the particle statistics (Bose or Fermi). At sufficiently high temperatures (Maxwell‐Boltzmann statistics), the T‐matrix introduced coincides with the usual T‐matrix of conventional two‐body scattering theory in free space. In low‐temperature Fermi systems, the T‐matrix differs from the reaction matrix of the Brueckner‐Goldstone theory because the “healing” property of the two‐body wave function does not obtain.
On Regularizations of the Dynamical Singularities by Crossing Terms in General Relativistic Gravitation Equations
Authors: Liebscher D.‐E. , Treder H.‐J.
Published: May 2007

An unified theory of gravitation and matter is tentatively described by adding phenomenological crossing terms to Einstein's equations. The impact on the singularity problem is discussed.
On the Gravitational Two‐Body Problem in Special Relativity
Authors: Afanasiev G. N. , Asanov R. A.
Published: May 2007

The method of POINCARÉ is applied to the consideration of the gravitational two‐body problem in the framework of Special Relativity. The formulation of the theory contains two arbitrary functions. A specific choice of these functions leads to the correct description of three crucial experiments, supporting General Relativity, and the time delay of radar signals. However, the gyroscope precession is three times less than that of GR (the realization of this experiment is planned this year). The expansion over the inverse powers of the light velocity being performed approximate Lorentz covariant two‐body equations without retardation effects are obtained. These equations are compared with the EIH two‐body equations.
Zum selektiven NMR‐Spinecho‐Verhalten bei Systemen mit I = 1 im Festkörper am Beispiel des Kaliumoxalatmonohydrats
Authors: Behrens H.‐J. , Schnabel B.
Published: May 2007

Es wird die Theorie des nichtselektiven Spinechoverhaltens im Festkörper für dipolar gekoppelte Spins I = 1 mit Quadrupolwechselwirkung nach BODEN u. Mitarb. [5] für den Fall der selektiven Einstrahlung auf nur eine Linie des NMR‐Spektrums modifiziert. Die theoretischen Ergebnisse werden mit 1H‐NMR‐Experimenten an den dipolar gekoppelten Protonenpaaren eines (KCOO)2 · H2O‐Einkristalls verglichen. Das ist möglich, weil die Interprotonpaarwechselwirkung in dieser Substanz wesentlich kleiner als die Intraprotonpaarwechselwirkung ist. Es ergibt sich ein Echoverhalten, das gewisse Ähnlichkeiten mit demjenigen heteronuklear gekoppelter Spinsysteme aufweist.
Heteronukleare Spinentkopplung unter dem Einfluß thermischer Bewegungen
Authors: Ernst H. , Fenzke D. , Pfeifer H.
Published: May 2007

Unter der Annahme magnetischer Dipol‐IS‐Wechselwirkung wird eine Theorie der heteronuklearen Spinentkopplung für “kurze” Korrelationszeiten entwickelt. Diese enthält als Spezialfälle die kernmagnetischen Relaxationsraten im rotierenden und im festen Koordinatensystem sowie die Kreuzpolarisation zwischen den Spins I und S. In Übereinstimmung mit dieser Theorie tritt für die protonenentkoppelte C‐13 Resonanz von Butanol, das in einem NaY‐Zeolith adsorbiert ist, ein Maximum der Linienbreite als Funktion der Temperatur zwischen − 150°C und + 90°C auf.
Moleküldynamische Berechnungen an einem zweidimensionalen Ensemble von Doppelzylindern ‐ ein Modell für die lamellare Phase von Phospholipiden
Authors: Frischleder H. , Werge C.
Published: May 2007

Mit der Methode der Moleküldynamik wurden die strukturellen und dynamischen Eigenschaften eines 2‐dimensionalen Systems von Doppelzylindern/Hanteln untersucht. Dieses System ist ein Modell für die lamellare Phase von Phospholipid/Wasser‐Systemen sowie der Biomembran‐Lipidkomponente. Die „herring‐bone”︁‐Struktur wurde als energetisch stabilste Anordnung der Hanteln in der Ebene gefunden, wobei sowohl die Molekülschwerpunkte als auch die Zylinderachsen pseudohexagonale Gitter bilden. Bei einer Teilchenzahldichte von 0,452 nm−2 und einer Temperatur von 310 K wurde ein lateraler Druck von (40‐60) dyn · cm−1 ermittelt, der mit experimentellen Werten von (30‐45) dyn · cm−1 sehr gut übereinstimmt. Die laterale Selbstdiffusionskonstante der Modellmoleküle ist im Vergleich zu experimentellen Werten um eine Größenordnung zu groß, die berechnete Rotationskorrelationszeit dagegen stimmt mit experimentellen Werten gut überein.
Darstellung temperaturabhängiger spektraler Eigenschaften des adsorptionsbedingten Emissionsrauschens durch Lorentzfunktionen
Authors: Kleint Ch.
Published: May 2007

Für eine erste Deutung der komplizierten Temperaturabhängigkeit der Spektraldichtefunktionen des Rauschens verschiedener Adsorptionssysteme wird eine Methode vorgeschlagen, die durch eine Darstellung der beobachteten Abhängigkeiten vermittels Lorentzfunktionen eine Zurückführung auf die hauptsächlich wirksamen Aktivierungsenergien (und Entropien) ermöglicht. Verschiedene Varianten werden begründet und einige Beispiele für die Anpassung an experimentelle Spektren gebracht.
Die Charakterisierung der Lösungen von Mastergleichungen, ein „inverses”︁ Problem
Authors: Alberti Peter M. , Uhlmann Armin
Published: May 2007

In einem endlich‐dimensionalen Parameterraum sei eine Kurve gegeben. Wir beantworten die Frage, wie diese Kurve beschaffen sein muß, um Lösung einer Mastergleichung zu sein.
Simultaneous Diffraction of Two Waves at a Transmission Volume Hologram
Authors: Kowarschik R.
Published: May 2007

On the basis of the theory of coupled waves the simultaneous diffraction of two waves at a plane dielelectric transmission volume hologram is described. The intensities of the output beams strongly depend on the phase shift between the incident waves and the phase shift of the holographic grating with respect to the interference pattern of the read‐out waves. This gives the possibility to transfer the energy from one beam into the other and can be used for the modulation and deflection of the reconstructed beams. The possibility of a separate determination of the different phase shifts by intensity or phase measurements is discussed.
On the Metric and Non‐metric Spaces for the Mechanics of Generalized Continua
Authors: Günther Helmut , Minagawa Sitiro
Published: May 2007

The paper is concerned with the description of structural defects of a mechanicof continuum in terms of geometry. It depends on the spacing of defects relatively to the spacing m the underlying discrete physical structure, if defects may be described separately by the continuup. picture; otherwise a microdistribution of defects is arising. It is shown, how the microrotations resni microdeformations of a micropolar resp. multipolar continuum give a phenomenological description for a remaining microdistribution of defects. Geometrically this is described by the Lemma of Riccl resp. the violation of this lemma.
On the Validity of Several Methods of Calculation of Vibronic Energy Relaxation Rates
Authors: Madzgalla I. , Paerschke H. , Süsse K.‐E. , Welsch D.‐G.
Published: May 2007

Different approximation methods of calculation of the rates of vibronic energy relaxation are studied and compared with an exact one. The molecular vibrations are described by harmonic oscillators, the positions of equilibrium of which are assumed to be different in different electronic states. The finite line widths of the vibronic states are taken into account. It is found that the approximation methods provide too small values of the relaxation rates, particularly as the coupling strength becomes weak.
Begründung einer Integralgleichung für die Bewegung eines strahlenden Elektrons II: Nicht‐lineare Näherung
Authors: Petzold J.
Published: May 2007

Die Strahlungsreaktion eines ausgedehnten, klassischen Teilchens wird in 3. Näherung analysiert. Das führt zu einer relativistischen Bewegungsgleichung, die eine ähnliche Form wie die in Teil I angegebene besitzt. Es bestehen jedoch Unterschiede im Zusammenhang zwischen der Ladungsverteilung und dem Kern der Integro‐Differentialgleichung.
Lifetimes of Excited Alkalilike Atoms Colliding by Van der Waals Forces with Inert Gas Atoms in the Groundstate
Authors: Siefart E.
Published: May 2007

The influence of Van der Waals forces on the lifetime of coherently excited hyperfine‐states |FimFi〉 and |FimFi〉 of alkalilike atoms i by collissions with inert gas atoms j in the groundstate |FjmFi〉 has been examined. To do this the timedependent Schrödinger equation has been solved on taking into account a static magnetic field, a radiation field and a Van der Waals force. Introducing an impact parameter model for the colliding atoms with small scattering angles which form a quasimolecule |μ〉 = |FimFiFjmFi 〉 an expression for the cross section σμμ has been derived which determines the halfwidth Γ μμ of the coherently excited states. On making use of the irreducible tensor representation the calculation of the cross‐section has been reduced to the calculation of multipole transitions. The result has been applied e. g. to the coherently excited 3d104p2P3/2‐states of Cu I colliding by dipole‐dipole interaction with inert gas atoms He I, and Ar I in the ground state. The values agree well with data which have been derived from zero‐level‐crossing experiments.
Damping of Quark‐Hadron Form Factors and Diffraction Scattering
Authors: Frenzel M. , Kallies W. , Lewin K.
Published: May 2007

Damping of hadron bound state wave functions in relative quark momentum as necessary to describe the beginning of power scaling at momentum transfer t ⋍2–3 GEV2 is obtained approximately from a corresponding behaviour of four‐and six‐quark Green's functions in which is required by diffraction scattering.
On Direct and Pair Correlation Functions of the Crystalline State and the Crystal‐Liquid Phase Boundary
Authors: Klupsch Th.
Published: May 2007

Assuming a non‐constant single particle density suitable to describe a bulk crystalline state and a crystal‐liquid phase boundary, the coupled ORNSTEIN‐ZERNIKE and PERCUS‐YEVICK equation to determine the direct and the pair correlation for a one‐component LENNARD‐JONES system are approximately solved. A hard core reference system is defined within a perturbation treatment; the corrections resulting from the true interaction can be calculated straighforward if the hard core solutions are known. The approximation involves a new class of exact solutions for the limiting case of strongly localized single particle densities.
On the Present Status of the Problem of Charge Dependence and Charge Asymmetry of the Nucleon‐Nucleon Force
Authors: Guratzsch H. , Kühn B. , Hahn K.
Published: May 2007

The charge dependence of the nucleon‐nucleon force can be derived from the low‐energy scattering parameters. The p‐p and n‐p parameters were measured in direct scattering experiments. The n‐n parameters ann = (‐16.70 ± 0.38) fm and rnn = (2.78 ± 0.13) fm have been determined from few particle reactions. The difference of the scattering lengths (ann ‐ ann) ≈ 7 fm demonstrates the violation of the charge independence. Information on the charge symmetry is still doubtful due to the inaccuracy of the charge correction for the p‐p parameters. Whereas the n‐n and the charge corrected p‐p parameters known at present yield a weaker n‐n force than the p‐p force, the opposite result follows from the binding energy difference for 3He and 3H and the meson theory of the nuclear forces.
On Treder‐Type Tetrad Theories of Gravitation I. Equivalence Principle and Invariance Properties
Authors: Bleyer U.
Published: May 2007

The Principle of relativity and the equivalence principle are the most important foundation of any theory of gravitation. We can formulate these principles by the help of the LORENTZ and the EINSTEIN groups. If we start with an action functional, the demand of invariance of this action with respect to these groups makes possible to get detailed conclusions about the general structure of theories of gravitation. EINSTEIN'S idea, to interpret gravitation as deformation of the local inertial systems of the special theory of relativity, leads to bi‐tetrad theories, which we call TREDER‐type tetrad theories. In this theories a sufficient number of gauge parameters is introduced in order to ensure the invariance of the action functional without limitations for the field variables.
Gravitational Field Equations with Cross‐terms and Static Equilibrium Configurations
Authors: Müller Volker
Published: May 2007

Considering Einstein's equations modified by additional cross‐terms we calculate spherically symmetric equilibrium configurations of cold degenerated matter. The effects of such modifications proposed by TREDER [5] to describe properties of a unitary field theory depend on the sign of the coupling and on some critical energy density. If this density is higher than the nuclear density, we do not find significantly larger equilibrium masses than in general relativity. However the modifications of the gravitional dynamics resulting from the cross‐terms become physically significant.
Auto‐Ionizing States in MgI
Authors: El‐Sherbini Th. M. , Rahman A. A.
Published: May 2007

Hartree‐Fock calculations have been performed for the auto‐ionizing levels of the 3pns, 3pnp, 4snp (n = 4 to 7) and 3pnd (n = 3 to 7) series in MgI. The calculated energies of the auto‐ionizing states are compared with the available results from photo‐absorption measurements and ejected‐electron experiments.
Thermodynamic Functions of Nonideal Hydrogen Plasmas
Authors: Ebeling W. , Richert W.
Published: May 2007

The contribution of the charged components to the thermodynamic functions is analysed on the basis of the present theoretical knowledge. In the high‐temperature low‐density limit the Debye formula with quantum corrections is used. In the low‐temperature high‐density limit the Gellman‐Brueckner formula for the electrons and a lattice‐energy formula for the protons is used. Padée‐approximants are constructed which contain these limiting situations as special cases and describe also the region between them in certain aproximation.
Elastic Scattering of Polarized Neutrons by 3He at Low Energy
Authors: Drigo L. , Tornielli G. , Zannoni G.
Published: May 2007

Elastic scattering by 3He for 1.67, 2.43, 3.0, 3.4 and 7.8 MeV neutron beams of known polarization was measured at seven angles from 25° to 155° using a high pressure gas scintillation counter. The geometrical and multiple scattering effects were accounted for by the Monte Carlo technique. The corrected results were compared with previous experimental data and with the existing predictions based on microscopic calculations and phenomenological analyses.
Quantenphysikalischer Ursprung der Eichidee
Authors: Bopp Fritz
Published: May 2007

Betrachtet man die Quantenphysik als Zusammenspiel von elementaren Erzeugungs‐ und Vernichtungsprozessen, so sind Eichfeldtheorien nicht nur möglich, sondern auch notwendig. Die komplex konjugierten Phasenfaktoren jedes Paares von Erzeugungs‐ und Vernichtungsoperatoren sind nämlich. willkürlich wählbar. Darum müssen Quantenfeldtheorien vollständig phaseninvariant sein. Das ist ohne Eichfelder nicht möglich.

Dem steht im Wege, daß die Diracgleichung nicht einmal global vollständig phaseninvariant ist. Multipliziert man nämlich die Komponenten der Erzeugungs‐ und Vernichtungsoperatoren mit verschiedenen konstanten Phasenfaktoren, so ändern sich die Diracmatrizen. Nur die Diracschen Vertauschungsrelationen bleiben invariant. Doch sind die Diracgleichungen vor und nach der Transformation physikalisch äquivalent. Man kann also sagen: Systeme freier Fermionen werden erst durch die Klasse aller äquivalenten Diracgleichungen vollständig dargestellt.

Da die Diracschen Vertauschungsrelationen gegen beliebige unitäre Transformationen invariant sind, ist die Klasse äquivalenter Diracgleichungen U 4‐invariant. Unitäre Diagonalmatrizen liefern willkürliche Phasentransformationen der Spinorkomponenten, so daß die zur Gruppe U 4 gehörigen Eichfelder zu eine allgemein phaseninvarianten Theorie führen. Sie ist so eng mit der QED verwandt, daß wir von einer „erweiterten Quantenelektrodynamik”︁, EQE, sprechen können.

Hier soll nur gezeigt werden, daß die EQE existiert. Dabei liefert die invariante Untergruppe U 1 von U 4 die QED. Die komplementäre Untergruppe SU 4 umschließt vier Untergruppen SU 3, drei Untergruppen O 4 und sechs Untergruppen SU 2. Letztere könnten den drei Paaren von Quarks und den drei Paaren von Leptonen entsprechen, wobei sich die Quarkpaare zu einer Gruppe SU 3 zusammenschließen. Mehr als zweimal drei Paare von elementaren Fermionen gibt es in der EQE nicht. Sie wird zwar kaum mit der vereinigten QED und QCD identisch sein. Doch sollte sie Vergleichbares leisten.

Tatsächlich folgt die EQE aus einer bereits vorhandenen, wenn auch wenig beachteten Symmetrie der empirisch bewährten Diractheorie. Sie ist darum einerseits im Sinne der Newtonschen Definition des Begriffs hypothesenfrei. Andererseits kann sie wegen der erforderlichen Phaseninvarianz kaum wegdiskutiert werden, was immer sie am Ende bedeuten mag. Die Erfindung neuer Symmetrien und die Anerkennung einer Unzahl unabhängiger Spinorkomponenten ist jedenfalls zunächst entbehrlich.
Gibt es Plancksche Sekunden des Kosmos?
Authors: Treder H.‐J.
Published: May 2007

Auf Grund der Planckschen Grenzen für die Energien der Quanten sind die minimalen Dimensionen des Kosmos nicht durch die Planckschen Einheiten, sondern durch die Heisenbergschen Abmessungen gegeben.
Über Volumendefekte und Krümmung in Riemannschen Mannigfaltigkeiten mit Anwendungen in der Relativitätstheorie
Authors: Gackstatter Fritz , Gackstatter Barbara
Published: May 2007

J. Bertrand und V. Puiseux haben gezeigt, wie man durch interne geodätische Messungen die Gaußsche Krümmung K einer Fläche bestimmen kann: Man konstruiert zu einem Punkt P den geodätischen Abstandskreis vom Radius r, mißt den Umfang L, dann kann K aus dem Defekt 2πr ‐ L berechnet werden. Ähnliche Relationen gibt es bei n‐dimensionalen Riemannschen Mannigfaltigkeiten mit positiv definiert Metrik, H. Vermeil hat gezeigt, daß man aus gewissen Volumendefekten die skalare Krümmung R bestimmen kann. In der vorliegenden Arbeit werden 4‐dimensionale Riemannsche Mannigfaltigkeiten mit Signatur (− + + +) studiert. Hier gibt es Zusammenhänge zwischen Volumendefekten, skalarer Krümmung R und physikalischen Größen der allgemeinen Relativitätstheorie.
Weshalb ist der Kosmos so groß?
Authors: Treder Hans‐Jürgen
Published: May 2007

Ausgehend von Eddingtons dimensionsloser Zahl ω ≈ 1040 und den Planckschen Fundamentalgrößen diskutieren wir eine Formel für die Massen M(n) im Universum. Für n = 0, 1, 2, 3, 4 ergeben sich Massenwerte, die im Kosmos realisiert sind. Die Formel wird auch für die negativen Zahlen n = −1, −2 diskutiert.
The Unified SU(2) × U(1) × U′(1)‐models of Electroweak Interaction of Leptons
Authors: Guliyev N. A. , Jafarov I. G. , Khalil‐Zade F. T. , Mehtiyev B. I. , Yakhyayev R. Sh.
Published: May 2007

The possible variants of the unified models of electroweak interaction of leptons in the framework of the broken gauge SU(2) × U(1) × U′(1)‐symmetry are constructed. In the first part analysis of SU(2) × U(1) × U′(1)‐symmetry breaking by the different combinations of two types of Goldstone‐Higgs fields: isodoublet φ and isosinglet Φ complex isovector ξ and Φ φ and ξ is considered. The second part is devoted to the construction of the feasible leptonic models in which the masses of the introduced leptons can be generated by symmetry breaking due to the fields considered in the first part. In the third part acceptability of these models from the point of view of available experimental data of cross‐sections of muonic neutrino and antineutrino scattering on electron has been investigated.
Optical Pumping of Metastable Argon Ions in a Hollow Cathode Discharge
Authors: Elbel M. , Quad R. , Simon M.
Published: May 2007

Metastable Argon ions which are produced by electron impact in a gas discharge, are optically pumped by irradiation with circularly polarized laser light in a magnetic field parallel to the laser beam. The pumping effect was made evident by monitoring the fluorescent light emitted after excitation. In particular, the polarization of the pumping light was alternately changed between circular and linear and synchronous changes of the fluorescent intensity were recorded. The obtained signal changed its sign, when the magnetic field was turned from parallel to perpendicular to the laser beam. From the intercept of the signal with the axis of the magnetic field the mean life of the metastable level could be inferred. It was shifted with rising pressure toward shorter values thus giving evidence of the dominating part played by collisions in the relaxation process. From the ratio of the signal and the total fluorescence the achieved orientation could be determined. It tells the ratio of the rates of pumping and relaxation. The relaxation time was found between 15 and 7 ns for Argon pressures ranging from 0.2 to 0.6 torr. The pumping time was two orders of magnitude larger than that.
Neutron Interference: Influence of the Mirror on the Spin
Authors: Audretsch J. , Lämmerzahl C.
Published: May 2007

Advanced neutron interferometry includes the spinor properties of the neutrons. This makes it necessary to consider the influence of the mirrors on the spinor propagation. It is shown how the effect of an arbitrary mirror can be uniquely decomposed into a known kinematical part which is necessarily present, and a dynamical part which goes back to an interaction the neutron experiences in its rest‐space. For any particular realization of a mirror this dynamical part can be determined experimentally. An argument is given as to why it vanishes for the usual perfect‐crystal interferometer. The first relativistic approximations of the spinor reflection formula are discussed.
Anharmonic Effects in Radiationless Vibronic Energy Relaxation
Authors: Madzgalla I. , Süsse K.‐E. , Welsch D.‐G.
Published: May 2007

A general expression for the vibronic energy relaxation rate, which includes the effect of coupling to external dissipative systems in a consistent way, is derived. In order to study the effect of anharmonic accepting modes of vibration on the internal conversion this rate expression is specified to the case of Morse‐type anharmonic displaced and distorted potential energy surfaces. Particularly, in the case of molecules such as bencene, the vibronic coupling of which is weak, the effect of strong enhancement of the decay rate due to anharmonicities as discussed in the literature could not been found.
On the Origin of Spacetime Distribution of Quasars I. The Simplest Model
Authors: Popić R. V.
Published: May 2007

The assumption that galaxies and massive black holes were both created in an early cosmological era, and allowing that quasars had to be made in their collisions, is tested comparing this theory with the observational data on the distribution of number of quasars N with respect to the cosmological redshift Z. The theoretical model is sensitive to Zc‐value of redshift at creational time, Zm‐value(s) of redshift at peak(s) of the distribution N(Z) and λ ‐ the decay constant of quasars. The peaks of distribution N(Z) are connected with the peaks in the mass spectrum of galaxies.
Streuung elektromagnetischer Wellen an rauhen Oberflächen mit anisotroper Autokorrelationsfunktion
Authors: Arnz M. , Ponath H.‐E.
Published: May 2007

Ausgehend von der in [1] gegebenen Streutheorie wird eine allgemeine Theorie der Streuung elektromagnetischer Wellen an einer rauhen Grenzfläche dargelegt. Für den allgemeinen Fall beliebig anisotroper Rauhigkeits‐Autokorrelationsfunktionen (AKF) werden die Spektraldichten aller Erreger‐ und Streulicht‐Polarisationsvarianten ermittelt.

Am Spezialfall einer elliptisch‐anisotropen Oberflächenrauhigkeits‐AKF wird die Messung der Lage der AKF‐Hauptachsen geschildert und die Auswertestrategie zur Ermittlung der AKF aus Streuindikatrix‐Messungen angegeben.
Power Asymptotes of Homogeneous Cosmological Models in Einstein's Theory of Gravitation
Authors: Müller V. , Schmidt H.‐J.
Published: May 2007

Completing the discussion of an earlier treatment (Borzeszkowski, Müller (1978)) homogeneous cosmological models of Bianchi‐types II, III, IV, VI and the models of Kantowski‐Sachs‐type are investigated. All asymptotes of the metric which have a power like dependence on the synchronized time near the cosmological singularity are listed. We assume an ideal fluid as source with the flow velocity orthogonal to the slices of homogeneity, and an equation of state π = βϱ 0 ⩽ β ⩽ 1. We utilize the fact that certain Bianchi types can be obtained by a limiting process from other ones. Special anisotropic matter‐dominated solutions have been found besides the well‐known Kasner asymptote.
A Study of the Thermal Hysteresis in AgNO3
Authors: El‐Kabbany F. , Badr Y. , Said G. , Taha S. , Mahrous S.
Published: May 2007

The reversible phase transformation of AgNO3 is studied. Dielectric constant, d.c. resistivity, differential thermal analysis (DTA) and dilatometric measurements show the occurrence of a reversible phase transition II→I at 160°C with heat of transformation H = 0.78 kcal/mol. The thermal hysteresis in this reversible transformation is examined, the magnitude of the temperature hysteresis does not exceed 12°C. An acceptable agreement is observed between the measured values of the transition temperature obtained by three different experimental techniques. The dilatometric analysis shows that this transition is accompanied by thermal shrinkage with relative shrinkage coefficient 8 × 10−4. Thermal analysis are also used to get thermodynamic and kinetic data of this phase transition. The temperature dependence of the dielectric constant and d.c. resistivity for single crystals as well as polycrystalline samples of AgNO3 have clearly located and confirm the phase transitions II→I→II with a strong support to its thermal hysteresis character. The conduction mechanism is found to be activated by energy 0.12 eV for phase I and 0.36 eV for phase II. The observed thermal behaviour of the various measured parameters is attributed to orientational disorder of the nitrate group leading to an order‐disorder phase transition which is reported here for first time in AgNO3.
Demokrit – Planck
Authors: Rompe Robert , Treder Hans‐Jürgen
Published: May 2007

Es gibt eine Physik, die an die Konstante h gebunden ist und die mit der Atomistik zusammenhängt. Diese h‐Physik geht eindeutig auf Planck zurück. Aber, aus dieser Physik folgt die Atomistik als Existenz lokalisierter geladener Teilchen unterschiedlichen Massen nicht, vor allem nicht die des Ladungsquants, so daß also Demokrit mehr behauptet hat, als die Quantenphysik zu beantworten kompetent ist.
Spin‐Phonon Interaction beyond the Limit of Spin‐wave Approximation
Authors: Chân Nguyẽñ Ngoc
Published: May 2007

By solving the system of equations for the doubletime Green functions, an expression for the energy spectrum of the spinsystem with the correction due to spin‐phonon interaction is derived. The utilized commutation relations for spin‐operators are more complicated than in the case of the spin‐wave approximation. In the lower temperature region, our expression becomes the one obtained by the spin‐wave approximation. The temperature dependence and the wave‐vector dependence of the broadening of the energy level are evaluated.
Photo‐ and Electro‐Production of a New Light Boson
Authors: Kim D. Y. , Zahir M. S. , Valluri S. R.
Published: May 2007

In GSI experiments, a light pseudoscalar boson of mass Φ 1.6 MeV may have been observed. In order to examine this possibility from a different aspect we propose to study the photo‐and electro‐production process of Φ‐particles. We calculate the cross section of neutral and charged Φ‐particles. We examine the possible role of these production mechanisms in the heavy ion collision processes.
Heisenberg's Cut and the Limitations of its Movability
Authors: v. Borzeszkowski Horst‐Heino , Wahsner Renate
Published: May 2007

It is shown that the Heisenberg cut cannot be arbitrarily far moved towards the observer
On the Combinatorial Foundations of Regge‐Calculus
Authors: Budach Lothar
Published: May 2007

Lipschitz‐Killing curvatures of piecewise flat spaces are combinatorial analogues of Lipschitz‐Killing curvatures of Riemannian manifolds. In the following paper rigorous combinatorial representations and proofs of all basic results for Lipschitz‐Killing curvatures not using analytic arguments are given. The principal tools for an elementary representation of Regge calculus can be developed by means of basic properties of dihedral angles.
Radiation damping in closed expanding universes
Authors: Bernui Armando
Published: May 2007

The dynamics of a coupled model (harmonic oscillator‐relativistic scalar field) in Conformal Robertson‐Walker (k = +1) spacetimes is investigated. The exact radiation‐reaction equation of the source‐including the retarded radiation terms due to the closed space geometry – is obtained and analyzed. A suitable family of Lyapunov functions is constructed to show that, if the spacetime expands monotonely, then the source's energy damps. A numerical simulation of this equation for expanding Universes, with and without Future Event Horizon, is performed.
A self‐consistent cluster study of the Emery model
Authors: Gros Claudius , Valentí Roser
Published: May 2007

We calculate Fermi‐surface properties of the Cuprate superconductors within the three band Hubbard model (also called the Emery model) using a cluster expansion for the proper selfenergy. The Fermi‐surface topology is in agreement with angular‐resolved photoemission data for dopings ∼ 20%. We discuss possible violations of the Luttinger sum‐rule for smaller dopings and the role of van‐Hove singularities in the density of states of the Zhang‐Rice singlets. We calculate the shift in the chemical potential upon doping and find quantitative agreement with recent experiments.
A finite size scaling study of the five‐dimensional Ising model
Authors: Rickwardt Ch. , Nielaba P. , Binder K.
Published: May 2007

For systems above the marginal dimension d*, where mean field theory starts to become valid, such as Ising models in d = 5 for which d* = 4, hyperscaling is invalid and hence it was suggested that finite size scaling is not ruled by the correlation length ξ (∝ |t| −1/2 in Landau theory, t being the distance from the critical point) but by a “thermodynamic length” l (∝ |t| −2/d). Early simulation work by Binder et al. using nearest neighbor hypercubic L5 lattices with L ⩽ 7 yielded some evidence for this prediction, but the renormalized coupling constant gL = −3 + 〈M4〉/〈M2〉2 at Tc was gL ≈ −1.0 instead of the prediction of Brézin and Zinn‐Justin, gL(Tc) = −3 + Γ4(1/4)/(8 π2) ≈ −0.812. In the present work, we try to shed light on this controversy obtaining much more precise Monte Carlo data using multihistogram techniques and lattices as large as L = 17 (i.e., 1419857 Ising spins). While our value of Tc agrees nicely with recent high temperature series work (KBTc/J ≈ 8.7774 ± 0.0035), the coupling at Tc {gL(Tc) ≈ −0.958 ± 0.050} confirms the work for small lattices and disagrees with the analytical prediction. Hence the data are better consistent with a shift of the effective critical temperature Tc(L) ‐ Tc(∝) ∝ L−d/2 rather than with L−(d−2) according to the analytical theory. If the latter behavior is correct, it can hence be seen for extremely large systems only.
Solutions for the T = 0 quantum spin glass transition in a metallic model with spin‐charge coupling
Authors: Oppermann R. , Binderberger M.
Published: May 2007

We solve several low temperature problems of an infinite range metallic spin glass model. A compensation problem of T 0 divergencies is solved for the free energy which helped to extract the quantum critical behaviour of the spin glass order parameters as a function of δJ = J – Jc (T = 0). The critical value Jc(T = 0) = 3/16pF−1 of the frustrated spin coupling J, which separates spin glass from nonmagnetic (spin liquid) phase, is determined exactly in the static saddle point solution for a semielliptic metallic band model in terms of the density of states at the Fermi level. In addition to the replica‐overlap order parameter 〈Qab〉, a ≠ b, the diagonal 〈Qaa〉 is confirmed as order parameter by the result 〈Qaa〉 SP ∼ (δJ)β, β = 1, and its susceptibility χaaaa ∼(‐δJ)−γ with γ = 1/2 at T = 0. The value for γ agrees with the one for the transverse field Ising spin glass. The low γ decay of 〈Qaa〉, ∼ T is obtained exactly in the whole quantum disordered phase including the critical value.