showing 36 of ~574560 from 574555 documents
Different strategies in optical recognition of polychromatic images.
1992
We treat two different problems in the recognition of polychromatic images: (1) recognition of an object with a given shape and color combination; (2) recognition of an object regardless of its color combination. To solve each problem we propose different strategies. The number of filters and the objects to which the filters are matched vary with the strategy. Phase-only filters have been used to achieve recognition of both problems. Computer results are given for different targets and scenes to show the behavior of the proposed strategies.
A SIMULTANEOUS ANALYSIS FOR THE ΔI = 1/2 RULE, DIRECT CP VIOLATION, $K^0 -\bar K^0$ AND $B^0 -\bar B^0$ MIXINGS
1992
To have a consistent picture, a simultaneous analysis for the K → ππ isospin amplitudes A0 and A2, the ΔI = 1/2 rule, CP-violating ε′/ε, and [Formula: see text] and [Formula: see text] mixings within the standard model is made by employing the recent reanalyzed values of the parameters and relating the penguin matrix elements involved in the K → ππ decays to the known matrix elements of the ΔI = 1/2 operator (Q2 − Q1) and ΔI = 3/2 operator (Q2 + 2Q1). The allowed values for all the relevant quantities are calculated in detail. A general bound for top quark mass mt, CP phase δ and ε′/ε is found: for δ in the second quadrant, 84 GeV ≤ mt ≤ 250 GeV , δ ≤ 173° and 1 × 10−4 < ε′/ε ≤ 1 × 10−2…
On the Multifractal Character of the Lorenz Attractor
1992
A detailed analysis of the Lorenz attractor in connection with generalized dimensions is presented in this work. Different methods have been employed to estimate these dimensions. Two of them are of standard type. A new method, based on the minimal spanning tree of the point distribution, is extensively tested in this work. It turns out that the Lorenz attractor is very appropriate for being analyzed through this technique, which produces a very clean estimate of the extrema scaling indices α min and α max . The different methods give qualitatively the same result: The Lorenz attractor has a multifractal character
On the lattice of J-subnormal subgroups
1992
The effect of age on mitogen responsive T cell precursors in human beings is completely restored by interleukin-2.
1992
Abstract It is well known that the function of T lymphocytes is significantly impaired by advancing age. In the present study, attempts have been made to further characterize the T cell impairment of elderly subjects. Thus, we have performed limiting dilution microculture analysis to evaluate the precursor frequency of T lymphocytes responding to a mitogenic stimulus in old and young subjects. Furthermore we have evaluated the activity of recombinant interleukin-2 (rIL-2) on these cells. The results demonstrate that in older subjects the frequency of these precursors is significantly decreased. The in vitro treatment with rIL-2 increased the frequency of mitogen responsive T lymphocyte prec…
Application of DNA techniques for identification using human dental pulp as a source of DNA
1992
Dental pulp tissue could be obtained in most cases from materials obtained under experimental conditions and from forensic casework (air accidents, burned and putrefied bodies). Teeth extracted during dental treatment (n = 30) were stored for 6 weeks and 4 years at room temperature. In addition teeth (n = 10) extracted from jaw fragments that had been stored for 15 years at room temperature, and teeth extracted post mortem from actual identification cases (n = 8) were investigated. Following extraction from dental pulp tissue the DNA concentration was measured by fluorometry. The amount of DNA obtained from the dental pulp tissue of a single tooth varied from 6 micrograms to 50 micrograms D…
Luminescence of Eu3+-doped lanthanum titanate (La2TiO5), a system with one-dimensional energy migration
1992
Abstract The titanate and Eu 3+ luminescence of a composition La 2 TiO 5 -Eu are reported as a function of temperature. At 4.2 K the quantum efficiency is very high, because the titanate excitation energy is localized. At 300 K there is delocalization and quenching centres are easily reached, so that the quantum efficiency becomes low. This is discussed in terms of the crystal structure, as are the peculiarities of the Eu 3+ spectra.
Geocronologia da província alcalina central, Paraguai Oriental: considerações preliminares
1992
Ultrasonography and gastric emptying: evaluation in infants with gastroesophageal reflux.
1992
We have applied ultrasonography to the evaluation of gastric emptying in children. Two different populations have been investigated: normal children and children with gastroesophageal reflux. All the patients were less than 6 months of age. The diagnosis of gastroesophageal reflux was defined by 24-h pH measurement. The technique, used to measure gastric emptying, is the one described by Bolondi et al. In this research we used the simplified method. All children had been submitted to the examination after 4-h fasting. The standard meal was the usual milk formula, 300 ml/m2 body surface area (BSA). A cross-section area of the gastric antrum was determined before a meal and every 15 min for 2…
Correlations of the nonexponentiality and state dependence of mechanical relaxations with bond connectivity in Ge-As-Se supercooled liquids
1992
We have studied the mechanical responses of supercooled Ge-As-Se liquids to flexural strains and temperature steps. The departures from exponential relaxation correlate well with the variations in connectivity. The structural state dependence of the mechanical relaxation, detected in pure and weakly cross-linked Se, is suppressed completely at the rigidity percolation threshold {l angle}{ital r}{sub {ital c}}{r angle}, where the liquid fragility is a minimum. The shapes of the decay functions of samples with the same {l angle}{ital r}{sub {ital c}}{r angle} but different compositions are not universal at {ital T}{sub {ital g}} probably because of chemical effects near the binary edges of th…
Ultrasonography for the diagnosis of Lyme disease in cases of acute facial paralysis.
1992
Ultrasonography of the parotid gland was introduced in 1989 as part of the diagnostic protocol of every patient treated in our clinics with acute facial paralysis. Ten of 50 patients so tested were found to have unilateral nonpalpable enlarged lymph nodes in the caudal portion of the parotid gland around the stylomastoid foramen. All 10 patients were eventually diagnosed as having Lyme disease. It is suggested that in patients with acute facial paralysis, ultrasonography is an inexpensive tool to improve diagnosis of Lyme disease and may have a more useful purpose in monitoring therapy.
Separation of T-cell-stimulating activity from streptococcal M protein
1992
The superantigenic properties of M protein type 5 of Streptococcus pyogenes have been implicated as an important pathogenicity factor in streptococcal autoimmune diseases. Here we show that after a single purification step by affinity chromatography on immobilized albumin or fibrinogen, M protein has no mitogenic activity for T cells. We demonstrate that the superantigenicity of M proteins of type 5 and type 1 is due to contamination with the highly potent pyrogenic exotoxins of S. pyogenes in the range of 0.1 to 0.01%. These results raise a general caveat for work with these extremely active T-cell mitogens, because the mitogenicity of other streptococcal or staphylococcal proteins could b…
Some observations on the automation by flow injection analysis of the spectrophotometric determination of amino acids and proteins witho-phthalaldehy…
1992
Automation by flow injection analysis with Spectrophotometric detection of the determination of total amino acids and proteins witho-phthalaldehyde is not straightforward. The use of spectrophotometry, instead of spectrofluorimetry, and of N-acetyl-L-cysteine, instead of the conventional mercaptoethanol is advantageous because of the lower variability of absorptivities with respect to fluorescence yields, and the larger stability of the derivatives. Under adequate working conditions and with leucine as reference, the procedure can be used for the evaluation of total amino acids. A similar procedure is proposed for the analysis of proteins in a sample. Limits of detection are ≈ 1 × 10−5M for…
Zur Frage der Darmkontrastierung in der abdominellen Computertomographie
1992
In 56 patients undergoing abdominal CT the gastrointestinal tract was defined by negative contrast instead of the conventional positive contrast from an iodine containing contrast medium. The contrast material was a 2 1/2% mannitol solution and was used for filling the rectum. Filling of the gastrointestinal tract was of similar quality to that obtained with positive contrast media. The number of artifacts due to high contrast boundaries was slightly greater with the negative contrast than it would have been with positive contrast. Differentiation of the gastrointestinal tract from other abdominal organs was equally good for both methods. The negative contrast method was poor in diagnosing …
Nuclear tests for the strange charge from factor of the nucleon
1992
Abstract It is shown that the measurements of elastic and inelastic scattering of neutrinos and parity-violating asymmetry of longitudinally polarized electrons on spin-isospin zero nuclei would yield model independent information about the strangeness charge form factor. Nunerical estimates of the contribution of this form factor are presented for 4 He, 12 C and 16 O nuclei in impulse approximation using strangeness vector from factors of the nucleon recently suggested in the literature. A general relation between the P -odd asymmetry in electron scattering and the cross sections of neutrino and unpolarized electron scattering on spin zero nuclei is obtained.
Two-loop calculation of the anomalous dimension of the axial current with static heavy quarks
1992
Abstract A method to perform two-loop calculations in Eichten's effective field theory for heavy quarks is developed. The anomalous dimension of the axial current for static heavy quarks is calculated at two loops. For N = 3, we get γ A (2) = − 1 36 [ 127 2 +28ξ(2)−5N f ] . This result is very important to understand completely the physical significance of the lattice measurement of the decay constant of the B meson. The two-loop correction generated by γ A (2) turns out to be small, less than 1% for four quark flavours, so that the value of the decay constant of the B meson does not need in practice renormalization group improvement. As extra results, the self-energy renormalization consta…
A natural and rigid model of quantum groups
1992
We introduce a natural (Frechet-Hopf) algebra A containing all generic Jimbo algebras U t (sl(2)) (as dense subalgebras). The Hopf structures on A extend (in a continuous way) the Hopf structures of generic U t (sl(2)). The Universal R-matrices converge in A\(\hat \otimes \)A. Using the (topological) dual of A, we recover the formalism of functions of noncommutative arguments. In addition, we show that all these Hopf structures on A are isomorphic (as bialgebras), and rigid in the category of bialgebras.
Book Review: Protective Groups in Organic Synthesis. 2nd Edition. Edited by T. W. Greene and P. G. M. Wuts
1992
LA SINDROME DI PRUNE-BELLY: Considerazioni cliniche e terapeutiche
1992
La Sindrome di Prune-Belly si può manifestare con una ampia varietà di quadri clinici,a prognosi variabile anche in rapporto al grado di compromissione renale. Gli Autori presentano uno studio retrospettivo su 6 casi osservati dal 1980 al 1991 e discutono l'importanza di un corretto inquadramento diagnostico e terapeutico
Tryptophan Fortification of Adapted Formula Increases Plasma Tryptophan Concentrations to Levels Not Different from Those Found in Breast-Fed Infants
1992
Several recent studies have demonstrated significantly lower plasma total tryptophan concentrations in formula-fed than in breast-fed infants. We have measured preprandial plasma amino acid concentrations in infants breast-fed or fed a formula with a protein concentration of 1.57 g/dl and with a whey/casein ratio of 60:40 or a formula with a protein concentration of 1.37 g/dl and a whey/casein ratio of 40:60 and fortified with 10 mg/dl (15 mg/100 kcal) of tryptophan. Healthy term infants (10 per group) were either breast-fed from birth or randomly assigned to one of the two study formulas. At 4 and 12 weeks of age, anthropometric measurements were performed and blood samples were obtained. …
Nonlinear optical susceptibilities of polysilanes: exciton effect
1992
Abstract Third-order nonlinear optical susceptibilities of σ-conjugated one-dimensional polymers have been calculated in a tight-binding model by taking account of the formation of excitons due to long-range Coulomb interactions. The spectrum of third-harmonic generation (THG) exhibits peaks due to excitons as well as unbound electron—hole states, in contrast to the linear absorption spectrum which is dominated by the lowest exciton state. The results are in excellent agreement with recent experiments in polysilanes not only for THG but also for linear absorption, two-photon absorption, and electroabsorption in a mutually consistent way.
Palaeogeographical relationships between Alpine and Jura glaciers during the two last Pleistocene glaciations
1992
Abstract Two main moraine complexes are usually defined in the northwestern Alpine piedmont: the External Moraine Complex (EMC) dated to the penultimate glaciation (“Riss” sensu lato) and the Internal Moraine Complex (IMC) dated to the last glaciation (“Wurm”). Until recently the prevalent concept was that these two complexes had been built by glaciers originating in the central Alpine zone. This paper presents a new palaeogeographical diagram, based on mapping and petrographical studies of these two moraine complexes, and especially on the relationships between Alpine and Jura tills. We reach the following conclusions. 1. (1) The Jura glaciers were independent of the Alpine glaciers during…
Iterative continuous maximum-likelihood reconstruction method
1992
Die präoperative Vorbehandlung von Stoffwechsel und endokrinologischen Erkrankungen zur Vermeidung postoperativer Komplikationen
1992
Unter 2280 Patienten, deren perioperatives Risiko nach abdominalchirurgischen Eingriffen prospektive erfast wurde, war der Diabetes mellitus mit 9,1% die haufigste Stoffwechselstorung. Diabetiker mit Notfalleingriffen hatten eine signifikant hohere perioperative Morbiditat und Mortalitat. Die praoperative Therapie bei Diabetes mellitus umfast neben der Blutzukkereinstellung die Kompensation von kardial-pulmonalen und renalen Funktionsstorungen, die Blutdruckeinstellung und Infektbekampfung. Auch bei Leberzirrhose ist das perioperative Risiko erhoht. Ansatzpunkte zu einer Senkung sind die Vermeidung einer Hypoxie und Hypotonie, die Durchfuhrung des kleinstmoglichen Eingriffes ohne Blutverlus…
Fluorometric determination of diphenhydramine by flow-injection analysis
1992
A sensitive, rapid and simple flow injection procedure for the determination of diphenhydramine has been designed based on a fluorometric approach. An aqueous solution of diphenhydramine is injected into a carrierreagent stream containing Ce(IV) in dilute sulphuric acid and the fluorescence intensity of the Ce(III) produced is monitored. Chemical, FIA and instrumental variables were optimized. Analytical features of the method are: linear range 0.2–2 ppm, precision 0.7%, sample throughput 80/h. The influence of some foreign substances which can be found in typical pharmaceutical samples containing diphenhydramine was also investigated. The diphenhydramine content of a pharmaceutical prepara…
Holomorphic mappings of bounded type
1992
Abstract For a Banach space E, we prove that the Frechet space H b(E) is the strong dual of an (LB)-space, B b(E), which leads to a linearization of the holomorphic mappings of bounded type. It is also shown that the holomorphic functions defined on (DFC)-spaces are of uniformly bounded type.
Inhibition of human immunodeficiency virus-1 infection by human conglutinin-like protein: in vitro studies.
1992
The lectin-like protein analogous to bovine conglutinin was purified from human serum. The carbohydrate-binding ability of conglutinin-like protein was inhibited by D-mannose, N-acetylglucosamine and L-fucose as well as by mannan-containing oligosaccharides. By applying a lectin-based ELISA system it was demonstrated that conglutinin-like protein binds to human immunodeficiency virus-1 (HIV-1) glycoprotein 120 (gp120) via its carbohydrate binding site. In vitro experiments with T-lymphoblastoid CEM cells revealed that conglutinin-like protein abolishes infection by HIV-1; a 50% cytoprotective concentration of 23.9 micrograms/ml was measured. These findings demonstrate that human conglutinin…
In vivo formation of aflatoxin B1-DNA adducts in parenchymal and non-parenchymal cells of rat liver
1992
The induction of hepatocellular carcinoma from liver parenchymal cells in laboratory animals by aflatoxin B1 (AFB1) is well documented. In contrast no tumours arising from the sinusoidal cell population have been reported after exposure to AFB1. The apparent resistance of the latter cell type was investigated at the level of DNA adduct formation in vivo in male Sprague-Dawley rats. Liver parenchymal and non-parenchymal cell populations were isolated from rats at 20 min and 1, 24 and 72 h after administration of 240 microCi (0.6 mg) [G-3H]AFB1/kg. AFB1-DNA binding was observed in both liver cell subpopulations and was 3- to 5-fold higher in parenchymal cells than in non-parenchymal cells. Th…
Center differences and cross-national invariance in help-seeking for panic disorder. A report from the cross-national collaborative panic study.
1992
Help-seeking behaviour for treatment of panic disorder was investigated in the sample of the Cross-National Collaborative Panic Study Second Phase. A total of 1168 patients were entered into this trial in 14 countries. Although there were significant center differences in prior treatment and utilization of health services there were also similarities. Treatment had been provided mainly by general practitioners. Drug treatment consisted mostly of prescription of classical tranquilizers and had a longer duration than treatment by psychotherapy. Patients with agoraphobic avoidance, past major depression and longer duration of illness used medical and psychiatric treatment facilities more inten…
Recoilles and resonant production of double-pion atoms
1992
Abstract We exploit two ideas found successful in the direct production of pionic atoms: recoilless condition and resonance production, in order to produce atomic systems with two bound π − . As an example of recoilless reaction we study π − + A X → p ( A−1 X , π − , π − ) , and as an example of resonant reaction we study π − X → ( π − π − X′) → π − X. In both cases the signals are found to be only a small fraction of the background indicating the big experimental difficulties that one is facing in producing these states.
Synthèse de chalcones à base de tétrathiafulvalène: RC(O)CHC(CH3)TTF, TTFC(O)CHC(CH3)R (R TTF: C6H3S4; Bct: C6H5Cr(CO)3; Fc: C5H4FeC5H5). Propr…
1992
Abstract Novel chalcones that contain tetrathiafulvalene (TTF) and/or metallocene (ferrocenyl or benchrotrenyl) moieties: RC(O)CHC(CH 3 )R′ (R and/or R′ TTF: C 6 H 3 S 4 ; Fc: C 5 H 4 FeC 5 H 5 ; Bct: C 6 H 5 Cr(CO) 3 ) were prepared using TiCl 3 /Et 3 N as the condensation reagent. The 1-1 charge transfer complex with TCNQ (tetracyanoquinodimethane was obtained for the ditetrathiafulvalenic derivative (R R′ TTF). This complex exhibits the semiconducting behaviour.
false
1992
A series of liquid-crystalline copolymers 1 with a chiral azobenzene moiety as photoreactive mesogenic unit was prepared. The polymers were fractionated and the mesophase behaviour of the high- and low-molecular weight fractions was examined. The copolymers display smectic A and cholesteric phases. For the cholesteric phases the pitch of the helix was determined, which ranges from 3 to 20 μm. Stable monolayers at the air-water interface were obtained from two monomers and one of the homopolymers. Multilayer assemblies of the azobenzene-containing polymers can be used to study photo-induced order/disorder transitions.
A Tracking and Timing (t-and-t) Front-end Electronics For Rpc Detectors
1992
Abstract The availability of a detector such as an RPC (resistive plate counter) opens new possibility on the future experiments for accelerator and non-accelerator physics. The main advantage consists on the possibility to obtain accurate tracking and timing with a low-cost detector and electronics. We report results on time resolution, signal transmission on long strips, efficiency and maintenance. A possible front-end electronics able to give tracking and timing information on each input channel operating in free-running mode will be illustrated toghether to the preliminary tests performed.
Evidence of magmatic activity related to Middle Jurassic and Lower Cretaceous rifting from northeastern Brazil (Ceará-Mirim): K/Ar age, palaeomagneti…
1992
The Mesozoic magmatic activity in the easternmost part of NE Brazil (Ceara-Mirim) is mainly represented by two-pyroxene tholeiitic dykes; only few dykes have alkaline character. K/Ar ages and palaeomagnetism data indicate that Ceara-Mirim dykes are of Middle Jurassic (175-160 Ma) and Early Cretaceous (140-130 Ma) age. Both Middle Jurassic and Lower Cretaceous dykes have high incompatible-element concentrations and TiO2 with the lower contents generally confined to the Middle Jurassic dykes; rare tholeiitic dykes low in TiO2 and incompatible elements are present. Sr/1bNd isotopic and other chemical data do not support appreciable crustal contamination and in a 87Sr86Sr vs. 143Nd144Nd diagram…
PERSISTENCE OF SOME PESTICIDES IN THE AQUATIC ENVIRONMENT
1992
Amylase release from streptolysin O-permeabilized pancreatic acinar cells. Effects of Ca2+, guanosine 5'-[gamma-thio]triphosphate, cyclic AMP, tetanu…
1992
The molecular requirements for amylase release and the intracellular effects of botulinum A toxin and tetanus toxin on amylase release were investigated using rat pancreatic acinar cells permeabilized with streptolysin O. Micromolar concentrations of free Ca2+ evoked amylase release from these cells. Maximal release was observed in the presence of 30 microM free Ca2+. Ca(2+)-stimulated, but not basal, amylase release was enhanced by guanosine 5′-[gamma-thio]triphosphate (GTP[S]) (3-4 fold) or cyclic AMP (1.5-2 fold). Neither the two-chain forms of botulinum A toxin and tetanus toxin, under reducing conditions, nor the light chains of tetanus toxin, inhibited amylase release triggered by Ca2…