showing 36 of ~574560 from 574555 documents
Todavía unas palabras sobre las venas cefálica y basílica
1993
Ever since 1879, when Josef Hyrtl first formulated his thesis that the names of the cephalic and basilic veins, as applied to the arm veins, were of Arab origin, a discussion began between philologists and historians of medicine as the former defended the Greek source of such denominations whilst the latter shared the view of the Viennese anatomist. The author, after making a critical review of the -relevant works published hitherto, unearthes a text drawn from a Persian manuscript dating back to the 15th century that, in his view, confirms the rigthness of the Viennese anatomist's thesis.
Gravity, Non-Commutative Geometry and the Wodzicki Residue
1993
We derive an action for gravity in the framework of non-commutative geometry by using the Wodzicki residue. We prove that for a Dirac operator $D$ on an $n$ dimensional compact Riemannian manifold with $n\geq 4$, $n$ even, the Wodzicki residue Res$(D^{-n+2})$ is the integral of the second coefficient of the heat kernel expansion of $D^{2}$. We use this result to derive a gravity action for commutative geometry which is the usual Einstein Hilbert action and we also apply our results to a non-commutative extension which, is given by the tensor product of the algebra of smooth functions on a manifold and a finite dimensional matrix algebra. In this case we obtain gravity with a cosmological co…
Molecular dynamics near the glass transition
1993
Solid state 13C NMR spectroscopy has been applied to investigate the time scale and the geometry of rotational motions near the glass transition of the low-molar-mass van der Waals glass former 1,3,5-tri-α-naphthylbenzene (T g = 342 K). Two-dimensional 13C exchange spectra were taken between 347 and 372 K. With the principal values of the 13C chemical shift tensors determined from 13C CP/MAS spectra and static one-dimensional 13C spectra, the two-dimensional spectra are interpreted according to the isotropic rotational diffusional model to yield mean correlation times τ0 in the range 10 ms ˇ- τ0 ˇ- 50 s, and a log-Gaussian distribution of correlation times with a width of 1·5 decades. The m…
Symmetry of molecular properties
1993
The symmetry of coefficients in the expansion of a given molecular property are shown to be obtainable through well defined tensor methods. The analytical expansions required of various vibrational and rotational tensors are given up to the fourth degree in dynamical variables. To illustrate the method, some rovibrational properties of spherical tops are considered. The symmetry of the associated molecular constants is expressed, simultaneously, for XY4 and XY6 molecules, by algebraic relations involving the independent constants and the coupling symbols of the molecular symmetry group. To allow comparisons, some examples are given for which the symmetry of the constants has been published …
CP Violation
1993
An overview of the phenomenology of CP violation is presented. The Standard Model mechanism of CP violation and its main experimental tests, both in the kaon and bottom systems, are discussed. (Lectures given at the 1993 Trieste Summer School and at the Escuela Latinoamericana de Fisica, ELAF'93, Argentina).
Second-order NLO main-chain polymers by polymerization of poled monomers
1993
A new method of preparing oriented NLO main chain polymers is presented. We synthesized NLO-monomers that consist of donor acceptor substituted tolane molecules that can be poled in the low molar mass state. In the oriented polar state these monomers can be chemically linked using a thermally activated polyaddition reaction. This reaction links the donor head of one monomer to the acceptor tail of the next hibiting bulk noncentrosymmetry with the average direction of the molecular dipoles parallel to the aligning field.
EPR studies of Mn, Fe, Co, and Cu doped PLZT and PMN compositions
1993
Results of Mn, Fe, Co, and Cu admixture EPR spectra studies in PLZT and PMN ceramics are discussed. The spectra of Mn, Fe, and Co ions with dominating absorption at geff = 2.0 and 4.3 are proposed due to d5 (S = 5/2) configurations (Mn2+, Fe3+, Co4+). The latter can be used as probes disclosing specific features (glass-like behaviour) of the structures. The Jahn-Teller ions (Mn3+, Fe4+, Co5+, Cu2+) are responsible for the dopant effect, e.g., the shift of the e(T) maximum to higher temperatures. The microscopic nature of differences of the dopant effect in PLZT and PMN materials and in the Mn Fe Co sequence is analyzed. [Russian Text Ignored].
Statistical properties of the eigenvalue spectrum of the three-dimensional Anderson Hamiltonian
1993
A method to describe the metal-insulator transition (MIT) in disordered systems is presented. For this purpose the statistical properties of the eigenvalue spectrum of the Anderson Hamiltonian are considered. As the MIT corresponds to the transition between chaotic and nonchaotic behavior, it can be expected that the random matrix theory enables a qualitative description of the phase transition. We show that it is possible to determine the critical disorder in this way. In the thermodynamic limit the critical point behavior separates two different regimes: one for the metallic side and one for the insulating side.
Arbitrage international. Exequatur en France d'une sentence rendue à l'étranger, Décision étrangère ayant rejeté le recours en annulation contre cett…
1993
International audience; (Paris, 12 févr. 1993, Rev. arb. 1993. 259, note D. Hascher ; Paris, 19 déc. 1991, Rev. arb. 1993. 300 et Civ. 1re, 10 mars 1993, Rev. arb. 1993. 258, note D. Hascher)
Arbitrage interne. Convention d'arbitrage prévoyant la suspension du délai d'arbitrage jusqu'à la communication des résultats de l'expertise, détermi…
1993
International audience; (Civ. 2e, 5 avr. 1993)
Interdiction des inscriptions après le jugement d'ouverture. Inscription provisoire d'une hypothèque judiciaire avant le jugement d'ouverture, Substi…
1993
International audience; (Com. 17 nov. 1992, BNP c/ Guyot ès qual.)
Arbitrage interne. Constitution du tribunal arbitral, Recours devant le Président du tribunal de grande instance statuant comme en matière de référé,…
1993
International audience; (Paris, 16 avr. 1992, Rev. arb. 1993. 431, note A. Hory ; Civ. 2e, 10 mars 1993, Rev. arb. 1993, note A. Hory)
Prognostic value of DNA analysis in colorectal carcinoma.
1993
BACKGROUND Reported experiences regarding the prognostic significance of DNA content in colorectal carcinoma have been a matter of controversy. METHODS DNA analysis with image cytometry was performed in 137 patients with colorectal cancer. Only patients who had resection without tumor residual and who did not die postoperatively as a consequence of the operation were entered in the study. At the time of DNA analysis, neither the histomorphologic data nor the relapse-free survival time of the patients were known. RESULTS In this investigation the DNA content of tumor cells had no univariate or multivariate influence on the relapse-free survival time. The prognosis was dependent on the tumor …
Arbitrage international. Clause compromissoire, Référence à des conditions générales, Consentement, Appréciation souveraine des juges du fond, Formal…
1993
International audience; (Civ. 1re, 3 mars 1992, JDI 1993. 139, note B. Audit)
Egalité des créanciers chirographaires. Inscription hypothécaire nulle, Créancier admis à titre chirographaire, Paiement par le liquidateur, Répétiti…
1993
International audience; (Com. 17 nov. 1992, SA Diffazur c/ Darrousez, ès qual.)
Déclaration des créances. Déclaration faite pour le compte d'une personne morale, Pouvoir du représentant, Défaut, Extinction de la créance
1993
International audience; (Caen, 17 déc. 1992, SOFINABAIL c/ SELVMI et Me Poincheval ; Caen, 7 janv. 1993, Société européenne de location de véhicules et de matériels industriels et autre c/ Poincheval, ès qual. et autre, Demande d'avis n° 0930001 par le tribunal de commerce de Lille, séance du 14 juin 1993 de la Cour de cassation)
Configurational entropy of microemulsions : The fundamental length scale
1993
Phenomenological models have been quite successful in characterizing both the various complex phases and the corresponding phase diagrams of microemulsions. In some approaches, e.g., the random mixing model (RMM), the lattice parameter is of the order of the dimension of an oil or water domain and has been used as a length scale for computing a configurational entropy, the so‐called entropy of mixing, of the microemulsion. In the central and material section of this paper (Sec. III), we show that the fundamental length scale for the calculation of the entropy of mixing is of the order of the cube root of the volume per molecule—orders of magnitude smaller than the dimension of such a domain…
Arbitrage interne. Indépendance de l'arbitre, Composition du tribunal arbitral, Intervention du président du tribunal de commerce. Recours en annulat…
1993
International audience; (Paris, 4 juin 1992, Rev. arb. 1993. 448, Wattelet c/ Société Geteba et Lorquin)
Arbitrage interne. Sentence, Recours en annulation, Annulation de la sentence, Examen du fond du litige par la cour d'appel, Limites, Mission du trib…
1993
International audience; (Com. 11 mai 1993, inédit)
SINGLET NEUTRINOS AS HOT DARK MATTER
1993
A model is presented that generates mass and magnetic moment matrices for singlet neutrinos radiatively at one-loop level. It allows the singlet neutrinos to account for the hot dark matter and the anomalous ionization of interstellar hydrogen.
Tau physics prospects at the tau-charm factory and at other machines
1993
7 páginas, 3 tablas.-- Comunicación presentada al 3º Workshop On The Tau-Charm Factory celebrado en Marbella (España) del 1 al 6 de Junio de 1993.
Perspectives on tau-charm factory physics
1993
30 páginas, 2 figuras, 3 tablas.-- Comunicación presentada al 3rd Workshop on the Tau-Charm Factory celebrado en Marbella (España) del 1 al 6 de Junio de 1993.
Interactions of liposomes and hydrophobically-modified poly-(N-isopropylacrylamides): an attempt to model the cytoskeleton
1993
The interactions of small unilamellar vesicles (SUV) and water-soluble copolymers were studied by fluorescence spectroscopy, differential scanning calorimetry (DSC) and quasi-elastic light scattering (QELS). The anchoring onto liposomal bilayer membranes of copolymers of N-isopropylacrylamide, N-(2-(1-naphthyl)ethyl)-N-n-octadecylacrylamide and or N-[4-(1-pyrenyl)butyl]-N-n-octadecylacrylamide (0.5 mol% of the octadecylacrylamide comonomer) was monitored by non-radiative energy transfer between excited naphthalene and pyrene. The anchoring process occurred on zwitterionic lecithin liposomes and on negatively charged phosphatidic acid liposomes, whether the bilayer was in the crystalline or …
Release of choline from rat brain under hypoxia: contribution from phospholipase A2 but not from phospholipase D
1993
Moderate hypoxia induced in rats by inhalation of 10% oxygen led to an increase of the concentration of free choline in the brain and caused a large net-release of choline from the brain into the venous blood as determined by the measurement of the arterio-venous difference. In hippocampal slices from rat brain, hypoxia increased the release of choline into the superfusion medium. The activity of phospholipase D, as measured by the formation of phosphatidylpropanol in the presence of propanol, was not stimulated under these conditions. However, the mobilization of choline was completely depressed by lowering extracellular calcium and by 0.1 mM mepacrine. We conclude that hypoxia leads to a …
Ernesta Foldāta vēstule Edgaram Vimbam 1993. gada 10. decembrī
1993
Ernesta Foldāta vēstule Edgaram Vimbam, kurā viņš raksta par ceļojumu uz ASV, atteikšanos no vizītes Harvardas Universitātē, tikšanos ar draugiem un radiem, Ziemassvētku dāvanu pirkšanu, vieslekciju iespējām Latvijas Universitātes Bioloģijas fakultātē, konferencēm par orhidejām, aktualitātēm tropu augu kultivēšanā Pasaulē, savu ceļojumu uz Latviju 1993. gadā. Vēstules beigās apsveikums Ziemassvētkos un Jaunajā gadā, paraksts un ar roku rakstīta pateicība. Drukāts mašīnrakstā uz 3 lapām. Glabājas Latvijas Universitātes Muzeja Botānikas un mikoloģijas kolekciju krājumā.
Osmotic and cryoprotective effects of a mixture of DMSO and ethylene glycol on rabbit morulae.
1993
Abstract Comparisons were made of the osmotic and cryoprotective effects on rabbit embryos preserved by vitrification with 2 solutions and by conventional freezing. Embryos obtained from rabbits killed 70 to 72 h after mating were used in the study (n = 948). Initially, toxicity of the 3 cryoprotectants was studied in fresh (unfrozen) embryos (n = 135). Subsequently, embryos placed in ethylene glycol (EG, 40% v/v; n = 88) and ethylene glycol with dimethyl sulfoxide (EG+DMSO, 20% v/v each, respectively; n = 344) were loaded into straws and plunged directly into liquid nitrogen. Embryos placed in 1.5 M DMSO and 20% heat inactivated rabbit serum were subjected to conventional freezing in a pro…
REDUCTION OF CONSTRAINT SYSTEMS
1993
Geometric modeling by constraints leads to large systems of algebraic equations. This paper studies bipartite graphs underlaid by systems of equations. It shows how these graphs make possible to polynomially decompose these systems into well constrained, over-, and underconstrained subsystems. This paper also gives an efficient method to decompose well constrained systems into irreducible ones. These decompositions greatly speed up the resolution in case of reducible systems. They also allow debugging systems of constraints.
Recherche de systèmes de cultures à moindre risque de maladies du pied et des racines de blé - A : Influence de la succession culturale
1993
International audience
Recherche de systèmes de cultures à moindre risque de maladie (pied et racines du blé) - B : Influence de l'itinéraire technique
1993
National audience
Energy and water vapour transfers in a particular shrub-grass intercrop: the fallow savanna
1993
National audience
Nonlocal symmetry for QED
1993
We demonstrate that QED exhibits a previously unobserved noncovariant, nonlocal symmetry. Some consequences are discussed.
Quantum cosmological approach to 2d dilaton gravity
1993
We study the canonical quantization of the induced 2d-gravity and the pure gravity CGHS-model on a closed spatial section. The Wheeler-DeWitt equations are solved in (spatially homogeneous) choices of the internal time variable and the space of solutions is properly truncated to provide the physical Hilbert space. We establish the quantum equivalence of both models and relate the results with the covariant phase-space quantization. We also discuss the relation between the quantum wavefunctions and the classical space-time solutions and propose the wave function representing the ground state.
Standard Model CP-violation and Baryon asymmetry
1993
Simply based on CP arguments, we argue against a Standard Model explanation of the baryon asymmetry of the universe in the presence of a first order phase transition. A CP-asymmetry is found in the reflection coefficients of quarks hitting the phase boundary created during the electroweak transition. The problem is analyzed both in an academic zero temperature case and in the realistic finite temperature one. The building blocks are similar in both cases: Kobayashi-Maskawa CP-violation, CP-even phases in the reflection coefficients of quarks, and physical transitions due to fermion self-energies. In both cases an effect is present at order $\alpha_W^2$ in rate. A standard GIM behaviour is f…
Strain differences in the ratio of synaptic body types in photoreceptors of the rat retina.
1993
In the retinal outer plexiform layer of seven different rat strains, synaptic bodies (SB) were counted and, according to their morphology, characterized as synaptic ribbons (SR), synaptic spheres (SS) or intermediate structures. It was found that absolute SB numbers showed relatively small variations while SR/SS ratios differed considerably between the strains investigated. These results are discussed with respect to retinal pigmentation and to formation and degradation, respectively, of synaptic ribbons.
Quadrature effects on the accuracy of flux calculations in realistic atmospheres
1993
Abstract We have investigated the accuracy of five different quadrature methods—equal steps in θ, equal steps in cos θ, Gaussian, double Gaussian and Gauss-Lobatto—on the accuracy of fluxes in realistic aerosol atmospheres, using the Gauss-Seidel method. In addition, a range of Gaussian quadrature stream numbers from two to 32 were compared. The atmospheric models considered are those recently presented by Lenoble, with the exception that we have used Henyey-Greenstein phase functions in place of Mie. Our results should be easily reproduceable by any other workers interested in similar realistic atmospheres. A table of Gauss-Lobatto weights and points is provided as an appendix.
false
1993
4-(4-Carboxyphenyl)-3,5-dioxo-1,2,4-triazolidin-1-yl moieties resulting from 4-(3,5-dioxo-1,2,4-triazolin-4-yl)benzoic acid (U4A) randomly attached to 1,4-polybutadiene form supramolecular aggregates which act as effective junction zones in new thermoplastic elastomers. Deuteron nuclear magnetic resonance (2H NMR) spectroscopy was used to investigate the molecular dynamics of the polymer backbone and the junction zones in selectively labelled samples. The spectra show motional heterogeneity along the polymer chain as well as in the supramolecular domains. Polybutadiene segments which are adjacent to these polar clusters are restricted in their mobility, even at temperatures 100 K above the …