Dynamics of mean-field spin models from basic results in abstract differential equations

1992

The infinite-volume limit of the dynamics of (generalized) mean-field spin models is obtained through a direct analysis of the equations of motion, in a large class of representations of the spin algebra. The resulting dynamics fits into a general framework for systems with long-range interaction: variables at infinity appear in the time evolution of local variables and spontaneous symmetry breaking with an energy gap follows from this mechanism. The independence of the construction of the approximation scheme in finite volume is proven. © 1992 Plenum Publishing Corporation.

Development of the H-point standard additions method for coupled liquid chromatography and UV-visible spectrophotometry

1992

Abstract This work establishes the fundamentals of the H-point standard additions method for liquid chromatography for the simultaneous analysis of binary mixtures with overlapped chromatographic peaks. The method was compared with the deconvolution method of peak suppression and the second derivative of elution profiles. Different mixtures of diuretics were satisfactorily resolved.

Thermal diffusivity measurements for Mg-Mn ferrites

1992

Abstract The thermal diffusivity of Mg-Mn ferrites is studied through a modified scheme of the photothermal deflection method able to derive the diffusivity of low-diffusivity samples and to avoid any influence of the vertical offset parameter. The examined samples have been realized under different preparation conditions producing different grain dimensions, and a negligible influence of the grain dimensions is found on the thermal properties.

Systematic study of low-spin states in even Cd nuclei.

1992

Low-lying low-spin collective states in even $^{106\mathrm{\ensuremath{-}}112}\mathrm{Cd}$ and $^{116}\mathrm{Cd}$ were investigated using in-beam and off-beam \ensuremath{\gamma}-ray and conversion-electron spectroscopy. New spin assignments and decay branching ratios for the levels in $^{106}\mathrm{Cd}$, $^{108}\mathrm{Cd}$, $^{110}\mathrm{Cd}$, and $^{112}\mathrm{Cd}$ were obtained. The present results essentially complement the level systematics from $^{106}\mathrm{Cd}$ to $^{120}\mathrm{Cd}$. From the new data, it is inferred that two sets of low-lying ${0}^{+}$ states having different excitation characteristics cross between $^{114}\mathrm{Cd}$ and $^{116}\mathrm{Cd}$. No correspondi…

Phenolic Compounds from Lactuca viminea L.

1992

Abstract The aerial part of Lactuca viminea L. was examined for the presence of phenolic compounds. Six different flavonoids were isolated and identified by UV spectra, TLC, HPLCDAD , 1H NMR and 13C NMR. They were identified as apigenin, luteolin, quercetin, luteolin-7-O-glucoside, quercetin-3-O-glucoside and luteolin-7-O-glucuronide-6″methyl ester. Three phenolic acids were also detected: caffeic, ferulic and chlorogenic acid.

Preparative Polar Organometallic Chemistry 2. Von L. Brandsma. Springer, Berlin, 1990. XII, 227 S., Broschur DM 86.00. - ISBN 3-540-52749-4

1992

Dielectric relaxation in crystals and ceramics derived from BaTiO3

1992

Abstract A dielectric relaxation is reported in a crystal of BaTiO3 and in ceramics with composition (Ba1-yCay)TiO3 (0≤y≤0.2) in the frequency and temperature ranges 106 to 109 Hz and 350 to 450 K, respectively. A minimum of the relaxation frequency occurs close to the ferroelectric Curie temperature. The relaxation is of dipolar-type.

Segregation and co-occurrence of larval cestodes in freshwater fishes in the Bothnian Bay, Finland

1992

SUMMARYTwo autogenic (Triaenophorus crassus and T. nodulosus) and four allogenic (Diphyllobothrium latum, D. dendriticum, D. ditremum and Schistocephalus solidus) larval cestode species were found in 13 out of 31 fish species studied from the Bothnian Bay, NE Baltic. Gasterosteus aculeatus was the most heavily infected fish with 4 larval cestode species; for two of them (D. ditremum and S. solidus) the three-spined stickleback was found to be the required fish intermediate host. Among allogenic cestode species, those restricted to different definitive host species segregated their larval population in relation to the fish host, while, for example, D. ditremum and S. solidus, both maturing i…

Education in a New Europe

1992

International audience

Inelastic neutron scattering measurements on Nd2Fe14B and Y2Fe14B single crystals

1992

Abstract Inelastic neutron scattering measurements have been carried out on Nd 2 Fe 14 B and Y 2 Fe 14 B single crystals. Temperature dependent acoustic magnon dispersion curves have been found along the high-symmetry directions [0,0,1] and [1,0,0] with a gap at (0,0,2). Soft mode behaviour at spin wave vector q = 0 was observed for Nd 2 Fe 14 B near the spin reorientation temperature. The inelastic scattering intensity decreases steeply for larger q . Therefore, the dispersion curves could be measured until the middle of the Brillouin zone only. The experimental results are discussed in the frame of a classical spin wave model.

RHEOLOGICAL BEHAVIOUR OF MICROCRYSTALLINE CELLULOSE HYDROGELS

1992

ABSTRACT An extensive study was made of the rheological behaviour of microcrystal1ine cellulose-sodium carboxymethyl cellulose (MCC-NaCMC) gels at six different concentrations. The effect of agitation time, storage time, shear rate and temperature on the viscosity of these thixotropic gels was analysed, over 7200 resulting values of being available to this effect The pseudoplastic and thixotropic characteristics of the gels was established and a progressive decrease in gel viscosity with increasing storage time was observed, although retaining stability. On the other hand, constant agitation for five minutes was found to reduce gel viscosity by 40 to 50%, regardless of concentration.

Polyunsaturated fatty acids in cultured cardiomyocytes : effect on physiology and beta-adrenoceptor function

1992

This study was carried out to investigate the influence of the membrane fatty acid composition on the basal electrical and contractile activities and the response to beta-adrenergic stimulation of rat cardiac muscle cells in culture. Cells were grown for 3 days in a conventional serum culture medium and then incubated for 24 h in synthetic media containing either n-6 or n-3 as the sole source of polyunsaturated fatty acids (PUFA). The n-6/n-3 ratio in the phospholipids was 0.9 in the n-3 cells and 13.1 in the n-6 cells compared with 6.3 in controls cells. Such modifications did not alter action potentials and the main parameters related to contraction, although shortening was slightly acce…

Treatment of idiopathic oligozoospermia with tamoxifen--a randomized controlled study.

1992

There is no conclusive evidence of the usefulness of tamoxifen in the treatment of idiopathic oligozoospermia (OAT-syndrome), as it has been used mostly in uncontrolled studies. We herein report on the controlled treatment of OAT-syndrome with tamoxifen versus placebo following a randomized design. Seventy-six men with sperm counts of 2-20 x 10(6) ml-1, sperm motility of 20-50%, and sperm morphology (abnormal cells) between 50 and 80% were involved in the study. Patients with varicocele, a history of testicular maldescent or genital inflammation were excluded. Thirty-nine patients received tamoxifen (30 mg daily), 37 patients placebo. There was a statistically significant increase in the me…

General analysis of weak decay form factors in heavy to heavy and heavy to light baryon transitions

1992

We present a complete analysis of the heavy to heavy and heavy to light baryon semi-leptonic decays in the heavy quark effective theory within the framework of a Bethe-Salpeter (BS) approach and demonstrate the equivalence of this approach to other work in the field. We present in a compact form the baryon BS amplitudes which incorporate the symmetries manifest in the heavy quark limit and which also show clearly the light quark dynamics. A similar form of the BS amplitude is presented for light baryons. Using the BS amplitudes, the heavy to heavy and heavy to light semi-leptonic baryon decays are considered. As expected there is a dramatic reduction in the number of form factors. An advant…

Cerebral potentials elicited by mechanical stimuli to the human leg: influence of artifacts

1992

Mechanical stimulation with a reflex hammer was applied to the quadriceps muscle tendon of healthy volunteers and patients. The time-locked electrical signals were recorded from the scalp. In all cases, reproducible potentials could be recorded, with latencies in a range of 20 ms to 100 ms. The potentials recorded in patients under complete spinal anesthesia were similar to those derived before the anesthesia. In brain dead patients who showed absence of median nerve or posterior tibial nerve SEP, reproducible potentials after mechanical stimuli could be recorded as well. The results suggest that the hammer taps lead to mechanical shock waves which are propagated along the body producing ti…

Depression in the community: a comparison of treated and non-treated cases in two non-referred samples.

1992

Family studies in non-patient samples may help to clarify whether or not treatment-seeking behaviour is substantially determined by clinical features of depression. Life-time risks of depression were investigated by structured clinical interviews (SADS-LA) in both a high-risk sample of depressed patients' first-degree relatives and an unscreened control sample of the general population: 34.6% of the high-risk sample versus 23.1% of controls were cases of depression, with a female preponderance in both groups. The rates of treated depression were 17.0% versus 8.5%. Female sex, greater age, higher severity of episodes, manic or hypomanic episodes recurrent course, and introverted and anancast…

Altered desaturase activities and fatty acid composition in liver microsomes of spontaneously diabetic Wistar BB rat.

1992

We examined the activities of delta 9, delta 6 and delta 5 desaturases and fatty acid composition of liver microsomes in the insulin-dependent spontaneously diabetic adult female Wistar Bio-Breeding (BB) rat. The diabetic BB rats were subcutaneously injected with different doses of protamine zinc insulin in order to be killed in hyper-, normo- or hypo-glycemic states. Desaturase activities, which are partially inhibited by spontaneous diabetes during the normo- and hyper-glycemic periods, were similarly affected by the various insulin treatment; delta 9 desaturase activity being more depressed than the desaturase activities of either delta 6 of delta 5. Insulin treatment with 10 I.U./kg bod…

POLITICS CLOAKED IN WORSHIP STATE, CHURCH AND LOCAL POWER IN PIEDMONT 1570-1770

1992

Mass Determination of Francium and Radium Isotopes by a Penning Trap Mass Spectrometer

1992

Abstract A tandem Penning trap mass spectrometer is used for mass measurement of radioactive isotopes produced at the on-line isotope separator ISOLDE/CERN. The mass is determined directly and with high accuracy by measuring the cyclotron frequency of the stored ions. Measurements were performed on 209 210 211 212 221 222Fr and 226 230Ra. A resolving power of 5 × 105 was used and an accuracy of 1·8 × 10−7 has been achieved.

An ion channel-gated adenylyl cyclase

1992

A report of an international collaborative experiment to demonstrate the uniformity obtainable using DNA profiling techniques

1992

This paper describes a collaborative exercise intended to demonstrate whether uniformity of DNA profile results could be achieved between different European laboratories. It was shown that this goal can be obtained provided that a common protocol is followed (specifically the use of a common electrophoretic buffer as being the most important parameter). Generally, lower molecular weight loci (with lower molecular weight fragments) such as YNH24 perform better than higher molecular weight loci such as MS43a. The results of the exercise are discussed in relation to the objectives of the European DNA profiling group (EDNAP).

The rhetorical construction of law

1992

CLUSTER MONTE CARLO ALGORITHMS IN STATISTICAL MECHANICS

1992

The cluster Monte Carlo method, where variables are updated in groups, is very efficient at second order phase transitions. Much better results can be obtained with less computer time. This article reviews the method of Swendsen and Wang and some of its applications.

Prevalence of antibodies to hepatitis C virus among patients with cryptogenic chronic hepatitis and cirrhosis

1992

Many cases of chronic hepatitis and cirrhosis cannot be attributed to a known cause and are collectively referred to as cryptogenic chronic liver disease. We have evaluated the role of the hepatitis C virus in the pathogenesis of this condition in a retrospective serum analysis for antibody to hepatitis C virus in 129 patients with cryptogenic liver disease. Other causes of chronic hepatitis and cirrhosis were ruled out by clinical, serum biochemical and serological techniques. All 129 patients were HBsAg negative, but 28 (22%) had antibody to HBcAg. Sera were tested by radioimmunoassays using recombinant peptides for antibodies to nonstructural (C 100-3 and C33c) and structural regions (C2…

A note on saturated formations

1992

Structure formation in doped discotic polymers and low molar mass model systems

1992

Abstract Doping of low molar mass materials or polymers, possessing disc-like units, with electron acceptors leads to the stabilization of columnar discotic phases or even to the induction of such phases in compounds which either display a nematic discotic phase or only an amorphous phase in the absence of the electron acceptor. The induced columnar phase corresponds frequently to a hexagonally ordered one. We have observed, however, in addition the induction of new columnar phases such as the rectangularly ordered (Dro) and the columnar nematic phase (Nc). The enhancement of the tendency towards the formation of columnar phases is a consequence of electron acceptor—electron donor complex f…

Magnetic resonances in low-dimensional spin systems

1992

Abstract We present magnetic resonance experiments in the frequency range of 35 to 460 GHz at low temperatures (1.5 K) for the two compounds CsNiCl 3 and (CH 3 ) 4 NMnCl 3 (TMMC). In both cases the large frequency range enables us to make a precise determination of the various coupling constants (exchange interactions and anisotropy parameters). For CsNiCl 3 we found a larger interchain exchange than previously determined. These constants can then be used for a critical evaluation of other related experiments. In TMMC we found resonances which cannot be explained by existing models.

Common risk factors of three diseases.

1992

Thermal properties of the tetrahydrate series MtM(M'EDTA)2·4H2O {Mt, M, M' = Co(II), Ni(II), Zn(II)}

1992

Abstract We report on the specific heat data of the ordered bimetallic compounds CoCo(CoEDTA) 2 ·4H 2 O and CoCo(NiEDTA) 2 ·4H 2 O in the temperature range 1.5−15 K. The magnetic specific heat is analyzed from an Ising model that assumes three different magnetic sublattices exchange-coupled by two distinct magnetic interactions, as well as local anisotropies on tetrahedral Co and octahedral Ni sites.

Effect of aging on metabolic zonation in rat liver: acinar distribution of GSH metabolism.

1992

The effect of age on the glutathione antioxidant system and its acinar distribution in rat liver was studied. GSH/GSSG ratio in blood and liver was lower in old than in young rats. Hepatic glutathione peroxidase and glutathione S-transferase activities were higher in old than in young rats, whereas hepatic gamma-glutamyl transpeptidase activity was lower in old than in young rats. Glutathione reductase and glucose-6-phosphate dehydrogenase activities did not change with age in rat liver. Total glutathione levels and glutathione peroxidase activity were higher in periportal than in perivenous areas of young rats, but this heterogeneous distribution did not occur in old rats. No change with a…

Copolymerization of methacryloyl-terminated PMMA macromonomers with methyl methacrylate

1992

Methacryloyl-terminated macromonomers (MM) of polymethylmethacrylate (PMMA) of two different molecular weights were prepared by group transfer polymerization (GTP). They were copolymerized with methyl methacrylate (MMA) by radical polymerization using toluene as the solvent. The relative reactivity of the MM, 1/r1, decreases with increasing initial MM concentration. This is interpreted as a consequence of the increasing viscosity of the reaction medium leading to an increasing diffusion control of the MM addition. At a constant weight ratio of MMA to MM the reactivity of the longer macromonomer is higher than of the shorter one. Increasing the molar ratio [MMA]/[MM], i.e. increasing the ave…

Effect of sublethal diazinon concentrations on the demographic parameters of Brachionus calyciflorus Pallas (Rotifera)

1992

Episodic deposition of the Lias in the Medianes nappe (western Switzerland): a record from mineralized ammonite-bearing beds

1992

Abstract Sinemurian and Pliensbachian depositional sequences from the starved distal northern continental margin of the Tethys are preserved in the Medianes Nappe (Western Swiss Prealps). They contain mineralized beds which include a variety of facies. The northern continental margin of the Tethys was broken into blocks, less than 50 km wide, during an extensional phase. The Sinemurian and Pliensbachian sediments in the study are vary in thickness from less than 50 m in the north to more than 200 m in the south. Although the upper Sinemurian to Pliensbachian mineralized beds are thin, between 0.10 and 0.50 m thick, they commonly contain several distinct faunal horizons stacked one upon anot…

TRANSIENT SEMICONDUCTOR DEVICE SIMULATION INCLUDING ENERGY BALANCE EQUATION

1992

An efficient numerical method for the solution of hot‐carrier transport equations describing transient processes in submicrometer semiconductor devices is proposed. The calculations of transient processes in submicrometer MOS transistor were carried out and compared with the results obtained by conventional drift‐diffusion model.

Auditory brain stem responses in patients with human immunotropic virus infection of different stages.

1992

Thirty patients (26 men, 4 women) with human immunotropic virus infection of different stages were examined. Eleven patients had a history of i.v. drug abuse, nine patients had a history of treated lues infection, and one patient suffered from Kaposi's sarcoma. At the time of the examination, opportunistic infections or acute encephalitis were not apparent in any patient. All patients underwent otoneurological examinations, including pure-tone audiometry, caloric vestibular testing, and recording of the auditory brain stem responses (ABR). Six patients reported onset of hearing impairment during the last 3 yr. Two of them had flat sensorineural hearing loss; in the other cases, pure-tone au…

A solenoid retarding spectrometer with high resolution and transmission for keV electrons

1992

Abstract We have built an electrostatic electron spectrometer combining both high resolution and large luminosity. The instrument consists essentially of two superconducting solenoids separated by a system of ring electrodes of 4 m in length. Source and detector are placed in the high-field regions of the superconducting solenoids, whereas the repellent analyzing electrostatic potential of the ring electrodes peaks at the minimum of the magnetic field in between these solenoids. The magnetic guiding field provides (i) the acceptance of the full foreward solid angle of 2π, (ii) the transformation of the transverse cyclotron motion into longitudinal motion parallel to the magnetic field. The …