Direct determination of lead in cola beverages by electrothermal atomic absorption spectrophotometry

1992

Ring size control in diorganotin sulphides by intramolecular SnN coordination

1992

Abstract The synthesis of intramolecularly coordinated organotin sulphides, [(Me2N CH2CH2CH2)2SnS]n (1) and [Me2NCH2CH2CH2Sn(Ph)S]n (2), is described. Compounds 1 and 2 are dimers in chloroform solution (n = 2). Compound 1 forms a centrosymmetric dimer with a planar rectangular Sn2S2 four-membered ring in its centre. The tin atoms show a distorted trans-cis-cis octahedral coordination by 2C, 2N and 2S. The tin-nitrogen distances are 2.810(3) and 3.158(5) A. Compound 1 can be regarded as a model substance for nucleophilic attack at penta-coordinate tin centres. Although the degree of intramolecular coordination of nitrogen to tin is temperature dependent, the four-membered Sn2Sn2 ring remain…

A New Species of Palarus Latreille from Spain with a Comparative Study on Nesting Behavior and Larvae in the Genus (Hymenoptera: Sphecidae)

1992

Palarus almerienis n. sp. is described from Spain (including imago, larva, and nesting habits). P. confusus Turner, currently considered a subspecies of P. ambustus Klug, is raised to full species status. The most important differences among the three species involve sculpture of the mesopleuron. The geographical distribution of these three taxa is discussed. Females of P. almeriensis excavate unicellular nests and capture not only Hymenoptera (the usual prey of the genus), but also Diptera (Stratiomyiidae). They make temporary closures and store the prey in the gallery before transferring it to the cell, which they dig during provisioning. Several species of Diptera (Miltogramminae) are na…

A Study of Bose-Einstein Correlations In e+e- Annihilation At 91 Gev

1992

This paper describes a study of Bose-Einstein correlations made using the ALEPH detector at LEP. The correlations are found to enhance the two particle differential cross section for pairs of identical pions by a factor which can be roughly parametrized by R(Q) = 1 + lambda exp(-Q2-sigma(2)), where Q is the difference in the 3-momenta of the two pions in their centre of mass frame, lambda = 0.51 +/- 0.04 +/- 0.11 and sigma = 3.3 +/- 0.2 +/- 0.8 GeV-1, which corresponds to a source size of 0.65 +/- 0.04 +/- 0.16 fm. The large systematic errors on these results reflect their strong dependence on the choice of the reference sample used in the analysis. This problem is believed to occur primari…

Profesors Dmitrijs Ivļevs: biobibliogrāfiskais rādītājs

1992

Saturs: Priekšvārds. Filoloģijas zinātņu doktors profesors Dmitrijs Ivļevs ? Ļ. Sidjakovs. Profesora D. Ivļeva publicētie darbi. (1962.-1990.) Profesora D. Ivļeva rediģētie un recenzētie darbi un izdevumi, par kuriem atbildīgs profesors. Profesora D. Ivļeva vadītās disertācijas. Raksti par profesoru D. Ivļevu. Sarunas, intervijas. Profesora D. Ivļeva publicēto darbu alfabētiskais rādītājs. Personu rādītājs.

Alternativas al alargamiento de miembros inferiores en el tratamiento de las discrepancias de longitud

1992

Las discrepancias de longitud de miembros inferiores responden a muy diversas etiologías y diferentes patrones de desarrollo de las mismas. Ambos factores pueden condicionar seriamente el tratamiento de las discrepancias de longitud. Por ello, es interesante recoger en varias consultas diversos parámetros (edad ósea, edad cronológica, y diferencia absoluta o porcentajes de discrepancia de longitud de MM. II.) para pronosticar la diferencia de longitud final en la madurez esquelética. En base a estos datos se podrá planificar el tratamiento de las discrepancias de longitud dependiendo de la etiología, malformaciones asociadas y de la diferencia al final del crecimiento. Genéricamente se acep…

The production of resveratrol (3,5,4'‐trihydroxystilbene) by grapevinein vitrocultures, and its application to screening for grey mould resistance

1992

The ability of grapevine in vitro cultures to synthesise the phytoalexin precursor resveratrol in response to ultraviolet light irradiations is investigated in order to develop methods for screening for resistance to grey mould (Botrytis cinerea Pers.) in grapevines produced as a result of somatic embryogenesis. It is demonstrated that resveratrol formation can be reproducibly induced in leaves of in vitro plantlets. Differences in the production of resveratrol among the three varieties of Vitis vinifera tested (Pinot Noir, Chardonnay and Cabernet Sauvignon) were consistent with observations regarding their field susceptibility to grey mould. The use of phytoalexin induction and of in vitro…

Photon and Pion Nuclear Absorption Mechanisms

1992

Using a microscopical many body approach to pion and photonuclear reactions we study the mechanisms of pion and photon absorptions with emphasis on the number of nucleons involved in the genuine absorption process.

Spectral invariance, ellipticity, and the Fredholm property for pseudodifferential operators on weighted Sobolev spaces

1992

The pseudodifferential operators with symbols in the Grushin classes \~S inf0 supρ,δ , 0 ≤ δ < ρ ≤ 1, of slowly varying symbols are shown to form spectrally invariant unital Frecher-*-algebras (Ψ*-algebras) in L(L 2(R n )) and in L(H γ st ) for weighted Sobolev spaces H infγ sup defined via a weight d function γ. In all cases, the Fredholm property of an operator can be characterized by uniform ellipticity of the symbol. This gives a converse to theorems of Grushin and Kumano-Ta-Taniguchi. Both, the spectrum and the Fredholm spectrum of an operator turn out to be independent of the choices of s, t and γ. The characterization of the Fredholm property by uniform ellipticity leads to an index …

La scolarisation maternelle à deux ans : analyse des effets pédagogiques et sociaux

1992

International audience; Le système éducatif français fait actuellement l'objet de pressions pour que soit étendue la scolarisation maternelle à l'âge de deux ans. Ces pressions sont fondées notamment sur l'argument que le milieu scolaire pourrait être un substitut efficace au milieu familial, en particulier lorsque celui-ci n'appara\ⁱt pas procurer à l'enfant les stimulations suffisantes. Concernant le fonctionnement du système scolaire, les cas ont été nombreux dans lesquels il s'est révélé exister une divergence nette entre les opinions "communes" et les faits objectivement mesurés, pour qu'il appraisse souhaitable de ne pas s'en tenir aux opinions. Sur cette question des effets de la mat…

Effects of Crystal Field Splitting and Surface Faceting on the Electronic Shell Structure

1992

The shell structure of the valence electrons is clearly observed in all alkali and noble metal clusters containing up to hundreds of atoms[1 – 4]. It is seen in the abundances of the clusters, in the ionization potential and in the polarizability. The shell structure of the valence electrons is closely related to the shell model of nuclei, but is simpler owing to the negligibly small spin-orbit interaction. The ability to produce all sizes of metal clusters has made the metal clusters a test ground for the super-shell structure[5].

Effects of Ciprostene on Restenosis Rate during Therapeutic Transluminal Coronary Angioplasty

1992

Ciprostene, a chemically stable prostacyclin analog was studied for its effects on restenosis in patients with coronary artery disease undergoing therapeutic percutaneous transluminal coronary angioplasty (PTCA). In a double-blind, randomized trial 32 patients were randomized to receive either ciprostene or the respective placebo. The infusion started intracoronarily at a rate of 40 ng/kg/min 20 min before introduction of the balloon catheter into the coronary artery. Thereafter infusion was continued intravenously for 36 hours at a rate of 120 ng/kg/min and a tapering off period until 48 hours. The quantitative analyses of the degree of coronary artery stenoses on the angiographic films be…

El transporte óseo : una alternativa en el tratamiento de los defectos óseos segmentarios masivos

1992

Se presentan 3 casos de pseudoartrosis infectada de tibia y 2 de necrosis ósea s postraumáticas, en las que tras la resección radical del fragmento infectado o desvitalizado quedó un masiv o defecto óseo segmentario . Fueron tratadas mediant e transporte óseo según la técnica de Ilizarov. En todos los casos se consiguió la consolidación en el defecto óseo segmentario. Uno de los casos presentó una infección a nivel del regenerado óseo que se trató con drenaje del absceso, relleno de hues o esponjoso homólogo y posterior recubrimiento con un colgajo por rotación de gemelo interno e injerto de pie l libre. Se concluy e que e l transport e óseo e s un método seguro, con e l que se consigue un …

Algunas consideraciones sobre la tramitación parlamentaria de la LORTAD : Ley Orgánica de regulación del tratamiento automatizado de datos personales

1992

Analiza el procedimiento parlamentario seguido en relación con la Ley Orgánica de Protección de Datos personales

DSMIIIR personality disorders of the schizophrenic spectrum as evidenced by family studies

1992

Ultrastructural study of the retina in late infantile metachromatic leukodystrophy.

1992

The autopsy of a 2-year-old girl revealed a clinically unrecognized metachromatic leukodystrophy (MLD) due to an aryl-sulfatase A deficiency, characteristically affecting the central and peripheral nervous system by demyelination and by accumulation of metachromatic material. The retina though reported clinically as normal, showed the same demyelinating process in the optic nerve including the papilla but an additional intraneuronal storage of MLD-typical lysosomal residual bodies in ganglion cell perikarya of the retina. Cells of the bipolar and photoreceptor layers as well as pigment epithelial cells were not affected by MLD-specific lysosomal storage. Thus, sulfatides seem to play a part…

Histoire et criminalité de l'Antiquité au XXe siècle. Nouvelles approches

1992

El mosaico del centauro, un eco de la antigüedad clásica en el Museo de Bellas Artes de Valencia

1992

EN EL MUSEO DE BELLAS ARTES DE VALENCIA SE CONSERVA UN MOSAICO (57 X 59 CM.) EN EL QUE SE REPRESENTA LA LUCHA ENTRE UN CENTAURO Y UN TIGRE. PROCEDE DEL LEGADO QUE DON FRANCISCO MARTINEZ BLANCH HIZO A LA REAL ACADEMIA DE SAN CARLOS DE VALENCIA EN 1835. SE TRATA DE UNA IMITACION RENACENTISTA DE UN PAVIMENTO MOSAICO DE LA VILLA DE ADRIANO EN TIVOLI, ACTUALMENTE EN EL STAATLICHE MUSEUM DE BERLIN, SI BIEN LA VERSION DE VALENCIA ELIMINA TRES DE LAS FIGURAS DEL ORIGINAL. LA MITOLOGIA GRECORROMANA PRESENTA AL CENTAURO COMO UN SER PRIMITIVO Y SALVAJE; EL SIMBOLISMO CRISTIANO LO VINCULO A LAS PASIONES DESENFRENADAS, LA VENGANZA, LA FUERZA BRUTA Y EL ADULTERIO, SIENDO LOS BESTIARIOS MEDIEVALES LOS QUE…

Factores que afectan a la cromatografía de exclusión molecular de (bio)polielectrolitos

1992

Début etfin de la neige de Yves Bonnefoy: el camino de la nieve y la palabra

1992

evelio@uv.es

Desequilibrios demográficos espaciales en el Camp de Túria y la Hoya de Buñol-Chiva

1992

El espacio contiguo a la periferia occidental del Área Metropolitana de València, integrada por las comarcas del Camp de Túria y la Hoya de Buñol-Chiva, presenta un comportamiento demográfico heterogéneo tanto a nivel intercomarcal como municipal. El origen de estas desigualdades espaciales se halla en los diversos movimientos de población (migraciones) acontecidos en los últimos decenios, particularmente el éxodo rural de los años sesenta y setenta y el proceso de descongestión del A.M.V. de los ochenta.

Role of Disorder on the Dynamics of a Nonlinear Model for DNA Thermal Denaturation

1992

The dynamics of thermal denaturation of DNA is a good example in which nonlinearity coexits with disorder. The amplitude of the motions is so high that bonds break and the base sequence is inhomogeneous since it contains the genetic code. Using a simple nonlinear model, we study the role of local inhomogeneities or of extended disorder on the dynamics of the localized excitations and on the denaturation rate by numerical simulations at constrained temperature. Approximate analytical results are obtained for the trapping of the breatherlike excitations by isolated defects and the statistical mechanics of the disordered molecule.

Stimulator cell-dependent requirement for CD2- and LFA-1-mediated adhesions in T lymphocyte activation by superantigenic toxins.

1992

Abstract The staphylococcal enterotoxins and related microbial T cell mitogens stimulate T cells by cross-linking variable parts of the T cell receptor (TCR) with MHC class II molecules on accessory or target cells. We have used cloned human T cells and defined tumor cells as accessory cells (AC) to study the requirements for T cell activation by these toxins. On AC expressing high levels of CD54 (intercellular adhesion molecule-1, ICAM-1) and CD58 (lymphocyte function-associated antigen-3, LFA-3), mAb to CD2 were relatively ineffective in inhibiting the response to the toxins and antibodies to the lymphocyte function-associated antigen-1 (LFA-1) did not inhibit at all. If added together, h…

María grávida: la iconografía del dogma de la encarnación de Jesucristo en María

1992

SOBRE EL MOTIVO DE LA GESTACION DE LA VIRGEN EXISTEN MUCHAS REPRESENTACIONES FIGURATIVAS, ALGUNAS CONSIDERADAS DE MAL GUSTO. LAS FUENTES DE INSPIRACION DE ESTE TEMA FUERON LOS TEXTOS DEL EVANGELIO, LOS DE LOS EVANGELIOS APOCRIFOS, LOS DE LOS PADRES DE LA IGLESIA Y LA LEYENDA DORADA DE JACOBUS DE LA VORAGINE. EL ORIGEN DEL TEMA ICONOGRAFICO SE ENCUENTRA EN LA REPRESENTACION DE LA VIRGEN APOCALIPTICA, QUE FUE EVOLUCIONANDO, SOBRE TODO EN ESPAÑA, HACIA EL TIPO DE LA INMACULADA. MUY REPRESENTADAS EN EL ARTE SON LAS REPRESENTACIONES DE LA ANUNCIACION, LA ENCARNACION DEL VERBO, LA VIRGEN DE LA ESPERANZA Y LA VISITACION DE MARIA A ISABEL; POR OTRA PARTE, LOS EVANGELIOS APOCRIFOS HAN SIDO FUENTE DE…

Variations morphologiques de l'oursin irrégulier disasteroidea Collyrites (Pygomalus) Analis (Agassiz): Implications taxonomiques, paléoécologiques e…

1992

Resume Les variations morphologiques de la forme generale et de l'anatomie du test de Collyrites (Pygomalus) analis ( Agassiz ) sont abordees pour 17 populations du Bathonien superieur du Bassin de Paris (Nievre, Saone-et-Loire et Sarthe), parfaitement calees dans l'echelle chronostratigraphique standard des ammonites jurassiques (zones a Retrocostatum et Discus). La description de la morphologie s'appuie sur l'analyse biometrique de 8 variablest et 8 indices traites par des methodes statistiques. Les effectifs eleves et l'amplitude de taille des individus permettent un suivi des modifications morphologiques au cours de l'ontogenese. Dans chaque population, la forme du test presente une var…

Coronanden mit 1,2-Dithio-ethen-Einheiten. II. Kristallstrukturen der beiden Thiakronenether 8,9-Dicyan-8,9-didehydro-7,10-dithia[12]krone-4 und 11,1…

1992

Multi-elemental determination of heavy elements in plastics using X-ray fluorescence after destruction of the polymer by molten sodium hydroxide

1992

In this paper a method is proposed for the multielemental analysis of Sb(III), Ba, Cd, Cr(III), Hg, Pb and As(III) in plastics, using X-ray fluorescence after alkaline decomposition and preconcentration by (co)precipitation. The organic matrix is destroyed by decomposition with sodium hydroxide melted in a silver crucible by the open system technique, using sodium nitrate as auxiliary oxidant. The variables which influence preconcentration are optimized: digestion time, pH, salinity, carrier and sodium diethyldithiocarbamate (DDTC) and sodium rhodizonate (R) as precipitants. The calibration curves were linear up to 200 μg of the element present, except for lead (150 μg) antimony(III) (100 μ…

Algebraische Approximationen hoher Ordnung an die Exponentialfunktion

1992

Im Zusammenhang mit der numerischen Behandlung von Anfangswertproblemen bei gewohnlichen Differentialgleichungen fuhrt der Begriff der absoluten Stabilitat bei sogenannten einwertigen Verfahren auf gewisse rationale Approximationen der Exponentialfunktion, wie z. B. Pade-Approximationen. Aus der Untersuchung dieser rationalen Approximationen haben sich verschiedene Theorien entwickelt, als Beispiel sei die Theorie der Ordnungssterne von Wanner, Hairer und Norsett genannt. Im selben Zusammenhang ergeben sich bei der Anwendung von mehrwertigen Verfahren algebraische Approximationen der Exponentialfunktion. In der vorliegenden Arbeit wird fur Butchers verallgemeinerte implizite Runge-Kutta Met…

Reoperation and the centrifugal pump?

1992

Postperfusion syndrome is still a problem in long cardiac operations using extracorporeal circulation (ECC). To evaluate whether or not centrifugal blood pumping during open heart surgery is beneficial, a randomized, prospective study was undertaken of 50 consecutive patients undergoing elective coronary artery bypass grafting. The patients were divided into two groups of 25 each. In group 1 a centrifugal pump (Biomedicus) was used as arterial blood pump, while in group 2 a roller pump (Stockert) was used. The two groups did not differ significantly and the number of variables during surgery was kept low (identical perfusion set, two surgeons, minimal cardiotomy suction). The parameters stu…

L'enseignement de la Révolution Française dans les classes de Quatrième et de Seconde : enquête et débat. Commentaires à propos d'un sondage sur l'en…

1992

National audience

Análisis y distribución de los tipos climáticos aplicados al estudio de los suelos de la Provincia de Valencia

1992

En la provincia de Valencia y para cada mes del año, se ha establecido una correlación múltiple entre la latitud, longitud y altitud (variables independientes) con la precipitación y temperatura (variables dependientes). Los coeficientes de correlación múltiple son suficientemente altos como para admitir la fiabilidad de los resultados. Para la temperatura la significación es del 99.9% para todos los meses del año, lo mismo que para la precipitación en la mayor parte de los meses del año. Asimismo se observa para una variación de 100 m de altura, un incremento de 30 mm de precipitación y de -0.49 C de temperatura. Todos estos datos nos han permitido obtener los correspondientes tipos climát…

Simulataneous application of charge coupled device array-detected Raman spectroscopy and differential scanning calorimetry to in situ investigation o…

1992

The combination of differential scanning calorimetry (DSC) with charge coupled device (CCD) array-detected Raman spectroscopy for the in situ investigation of phase transition is illustrated using ammonium nitrate as an example. This method aids unambiguous characterization of different phases by providing a simultaneous probe of thermodynamic and vibrational data. The availability of real-time vibrational data, including both the internal and external mode regions, is unique to array-detected Raman spectroscopy. The intensity changes of the symmetric stretching mode ν1 of the nitrate ions and the lattice vibrations, that accompany the phase transition IV → II of ammonium nitrate, are ratio…

Sur la force d’adhésion entre un oxyde et un substrat métallique : conséquences dans le déroulement de l’oxydation

1992

Le travail porte d’une maniere generale sur les morphologies observees lors de l’oxydation des metaux IV et VA et permet de comparer les resultats obtenus pour Ti, Nb, et Zr. Une analyse est developpee dans le cas particulier du zirconium a partir des resultats cinetiques (ex : break-away) et morphologiques (effets de bords et ruptures aux aretes) obtenus lors de l’oxydation de plaques de zirconium de dimensions finies. Ces ruptures et decollements de la couche d’oxyde aux aretes sont analysees en generalisant la theorie d’Obreimov-Landau a partir des concepts d’adhesion et d’energie de surface de solides. Elle permet de comparer l’energie elastique accumulee dans l’oxyde au travail d’arrac…

Leptechioceras (Neomicroceras) Donovan, 1966 (Ammonitina, Echioceratidae, Sinémurien, Europe du Nord-Ouest): Taxon progénétique ou microconque?

1992

Resume Des faunes d'ammonites inedites collectees banc par banc dans des series epaisses a dominante argileuse duSinemurien terminal du Bassin parisien (Cher, France) sont decrites. Certains des peuplements etudies sont esentiellement constitues d'ammonites de petite taille attribuees au sous-genre Leptechioceras (Neomicroceras) ; le rattachement de ces formes aux Echioceratidae, alors qu'elles etaient initialement interpretees comme des Eoderoceratidae, est base sur des arguments cladistiques et est confirme par les observations stratigraphiques. Une nouvelle espece, la plus tardive du sous-genre, Leptechioceras (Neomicroceras) sparsicosta est decrite. L'originalite en termes d'heterochron…

Väliin lankeaa varjo : angloamerikkalaisen kaunokirjallisuuden välittyminen Suomeen 1890-1939

1992

Viime vuosikymmeniä pidetään angloamerikkalaisen kulttuurin valtakautena Suomessakin, mutta ennen toista maailmansotaa se oli suomalaisille nykynäkökulmasta katsoen yllättävänkin kaukainen ja vähän tunnettu kulttuuri. Tässä tutkimuksessa selvitetään välittäjien - erityisesti kustantajien, julkisen kritiikin ja tutkimuksen - vaikutusta siihen, millaiseksi angloamerikkalaisen kaunokirjallisuuden profiili Suomessa muodostui vuosina 1890-1939. Tutkimuksessa tarkastellaan, millainen kirjallisuus välittyi parhaiten suomalaisille lukijoille ja millainen taas jäi "varjoon". Siinä osoitetaan, että ulkomaisen kirjallisuuden välittyminen kytkeytyi tiiviisti yhtäältä suomalaisen yhteiskunnan yleisen ku…

Superparamagnetism in Ising Clusters

1992

Recent experiments on small ferromagnetic clusters have inspired introduction of a number of seemingly quite different theoretical models. We shall argue that all these models show superparamagnetic behaviour above the blocking temperature but below the Curie temperature. In particular, we shall show that Ising clusters display superparamagnetism and introduce a simple correction to the usual tank behaviour of magnetisation which has to be included for very small clusters. We also discuss the dependence of magnetisation on coordination number.