Showing papers by "University of Valencia published in 1989"
TL;DR: In this paper, the structure of the effective couplings induced by vector and axial-vector exchange is model independent, provided consistency with QCD asymptotic behaviour is incorporated.
723 citations
TL;DR: The present paper reviews the active, natural principles and crude extracts of plants which have been experimentally studied for hypoglycemic activity in the last ten years.
474 citations
TL;DR: In this article, a simple extension of the standard theory where neutrinos decay dominantly into invisible modes involving a majoron associated with the spontaneous violation of B -L symmetry due to physics at or below the electroweak scale is presented.
330 citations
TL;DR: Arsenate proved to be competitive with the highand low-affinity phosphate uptake system and induced transient membrane potential changes of up to 120 mV which were similar to those induced by phosphate and indicated a cotransport mechanism with at least 2H+/H2As04.
Abstract: Interference of arsenate and vanadate with phosphate uptake in Lemna gibba L. was studied by measuring voltage changes and (32P)phosphate uptake. Arsenate proved to be competitive with the highand low-affinity phosphate uptake system. It induced transient membrane potential changes of up to 120 mV which were similar to those induced by phosphate and indicated a cotransport mechanism with at least 2H+/H2As04. The amplitude of the transient arsenate-induced membrane depolarization was strongly influenced by phosphate starvation. A permanent membrane depolarization to the diffusion potential was achieved within 2 to 6 h in P-starved plants. Thus, arsenate is indeed a strongly competitive physiological analogue of phosphate in higher plants. Vanadate was easily transported into L. gibba as concluded from transient Em changes of up to 110 mV. Vanadate interfered only slightly and non-specifically with the two phosphate transport mechanisms. Like phosphate, vanadate uptake seems to be an H+-cotransport mechanism, both with similar optima at pH 6 0. Unlike phosphate uptake, vanadate-linked membrane depolarization was not affected by high intracellular phosphate concentrations. P-starvation did not enhance the weak long-term effect on Em. Hence, vanadate, in contrast to arsenate, is not regarded as a physiological phosphate analogue. The distinct and rapid vanadate-induced and permanent membrane depolarization of Avena sativa, Triticum aestivum and Glycine max leaves was not seen in Lemna nor in leaves of Gossypium hirsutum and Nicotiana tabacum. Plasmalemma-enriched preparations of L. gibba revealed, however, a high vanadate-sensitive ATPase activity (87%). As a possible explanation for these differences it is suggested that the latter plant species have cytosolic vanadate-detoxifying properties, i.e. they can reduce vanadate to vanadyl ions, in contrast to the former group of plant species.
319 citations
01 Jan 1989
192 citations
TL;DR: It is shown that a single dose of 25 mg/kg of imipramine, administered before or immediately after training on Day 1, increases rat's mobility on Day 2, thus suggesting that imipramsine alters the consolidation process.
168 citations
TL;DR: In this paper, a significant transverse energy dependence of the yield of J Ψ's relative to muon pairs produced in the mass continuum was observed for the first time, in agreement with predictions from quark-gluon plasma formation.
158 citations
TL;DR: This paper reviews the literature on recent antimicrobial plant products and medicinal plants used for the treatment of infectious diseases and includes accounts of extracts, essential oils and other active principles isolated from plants that have been used in folk medicine as antimicrobial agents.
Abstract: This paper reviews the literature on recent antimicrobial plant products (1978–1988) and medicinal plants used for the treatment of infectious diseases. The review includes accounts of extracts, essential oils and other active principles isolated from plants that have been used in folk medicine as antimicrobial agents. The name and part of the plants studied, the spectrum of activity, type of active compounds and methods used are discussed, as are their mechanisms of action.
150 citations
TL;DR: In this paper, an alternative approach to atmospheric correction is proposed based on the idea that the atmospheric effects over two or more dates can be determined in a relative way, by using the apparent reflectance values of surfaces whose ground reflectance can be considered unchangeable with time.
Abstract: Studies that use multitemporal images require the conversion of original digital data into the corresponding physical magnitudes. Atmospheric correction is one of the most important steps in this process, which is usually undertaken using atmospheric radiative transfer models. The main difficulty in these models is the need of atmospheric input data which are not usually available. An alternative approach to atmospheric correction is proposed in this Letter. It is based on the idea that the atmospheric effects over two or more dates can be determined in a relative way, by using the apparent reflectance values of surfaces whose ground reflectance can be considered unchangeable with time. This method has been applied to correct Landsat-5 Thematic Mapper images and satisfactory results have been obtained in comparison with those obtained by a traditional model.
150 citations
TL;DR: The first measurements of the mass and width of the Z 0 at the DELPHI Collaboration at the LEP Collider were presented in this article, where the authors derived the measurements from the multihadronic final states produced in e + e − annihilations at several energies around the 0 mass.
147 citations
TL;DR: In this paper, the use of alternative thiols and ophthalaldehyde-like reagents is also reviewed, as well as their use in the formation and degradation of isoindoles.
TL;DR: In this paper, a theoretical model that permits knowing the relationship between the temperature of the radiative system (the orange grove) and the temperatures of each part (ground, orange tree side, and orange tree top) was developed.
TL;DR: The in vitro antimicrobial activity of chloroform and methanol plant extracts were assayed using the agar‐streak method and 38 of them showed activity against some of the microorganisms tested.
Abstract: The antimicrobial properties of 59 plants used in folk medicine to treat general infectious diseases were studied. The in vitro antimicrobial activity of chloroform and methanol plant extracts were assayed using the agar-streak method and 38 of them showed activity against some of the microorganisms tested. Bioautography established the probable active compounds. Inhibition bands were identified as containing terpenoids and polyphenolic compounds.
TL;DR: The expression for the plasmon{r arrow}{nu}{bar {nu}} decay rate is rederived and the dispersion relation of a massless neutrino propagating in matter in the presence of an external magnetic field is determined.
Abstract: Using covariant methods we calculate the neutrino electromagnetic vertex in a gas of electrons to lowest order in a loop expansion and to the lowest order in $\frac{1}{{M}_{W}^{2}}$. The new induced terms, while they are chirality preserving, yield additional contributions to the dipole moments in the nonrelativistic limit. These are identical for particles and antiparticles and so need not vanish for Majorana neutrinos. As applications of our formulas, the expression for the $\mathrm{plasmon}\ensuremath{\rightarrow}\ensuremath{
u}\overline{\ensuremath{
u}}$ decay rate is rederived and the dispersion relation of a massless neutrino propagating in matter in the presence of an external magnetic field is determined. The possible implications of these effects are considered.
TL;DR: This paper presents a branch-and-bound algorithm for the exact solution of the Tree QAP based on an integer programming formulation of the problem and the bounds are computed using a Lagrangian relaxation of this formulation.
Abstract: The Tree QAP is a special case of the Quadratic Assignment Problem QAP where the nonzero flows form a tree. No condition is required for the distance matrix. This problem is NP-complete and is also a generalization of the Traveling Salesman Problem. In this paper, we present a branch-and-bound algorithm for the exact solution of the Tree QAP based on an integer programming formulation of the problem. The bounds are computed using a Lagrangian relaxation of this formulation. To solve the relaxed problem, we present a Dynamic Programming algorithm which is polynomially bounded. The obtained lower bound is very sharp and equals the optimum in many cases. This fact allows us to employ a reduction method to decrease the number of variables and leads to search-trees with a small number of nodes compared to those usually encountered in problems of this type. Computational results are given for problems with size up to 25.
TL;DR: Differences in risk-perception among U.S., Spanish, West German, and Brazilian drivers are investigated to provide information concerning the desirable country- and age-specific emphasis in driver education, driver licensing, and public information campaigns.
TL;DR: Results of the clinical study of 760 first mandibular molars showed that 20 teeth had three canals in the mesial root, and 13 had an intermediate canal which joined the mesiobuccal canal in the apical third.
Abstract: Traditional teaching of the anatomy of root canals in different teeth can lead clinicians into the misguided belief that a predetermined number of root canals is always present in any given tooth. A new understanding of the root canal system has enabled the location of additional canals. Results of the clinical study of 760 first mandibular molars, showed that 20 (2.6 per cent) had three canals in the mesial root. Of these 20 teeth, 13 (65 per cent) had an intermediate canal which joined the mesiobuccal canal in the apical third. In six cases (30 per cent) it joined the mesiolingual canal in the same area. In only one case did the intermediate or third canal retain its individual nature and end in an independent foramen.
TL;DR: Theoretical scenarios include isosinglet neutral heavy leptons which are present in many extensions of the standard electroweak theory such as superstring inspired models as discussed by the authors, and it can occur in a two-generation model.
TL;DR: Ten new cases of peripheral neuroepithelioma of soft tissue are reported, based on their histologic, immunohistochemical, and electron microscopic findings, with an ominous outcome in nine cases.
TL;DR: In this article, it is shown that thermal stresses affect the thermal expansion, but they relax after some time of storage, and that the anisotropic thermal expansion is linear in the range from room temperature up to 800°C.
TL;DR: The anti-inflammatory activities of the n-hexane extract of Sideritis javalambrensis and several purified fractions were investigated using the carrageenan mouse paw edema test and isolation of the active principles ent-16-hydroxy-13-epimanoyl oxide and esters of tyrosol with palmitic, stearic, behenic, and lignoceric acids was led to.
Abstract: The anti-inflammatory activities of the n-hexane extract of Sideritis javalambrensis and several purified fractions were investigated using the carrageenan mouse paw edema test. Progressive fractionation led to the isolation of the active principles ent-16-hydroxy-13-epimanoyl oxide [1] and esters of tyrosol with palmitic, stearic, behenic, and lignoceric acids.
TL;DR: A majority of drivers in each country rated themselves positively on all driving-related scales studied, and significant effects of country, age group, and sex of the subjects were present for several of the scales.
TL;DR: The results show that the oral intake of GSH is a safe and efficient form of administration of its constituent amino acids in cases when GSH synthesis is required to replete hepatic GSH levels.
Abstract: Administration of oral glutathione (GSH) increases hepatic GSH levels in fasted rats, in mice treated with GSH depletors such as diethyl maleate and in mice treated with high doses of paracetamol. An increase in hepatic GSH levels after administration of oral GSH does not occur in animals treated with buthionine sulphoximine, an inhibitor of GSH synthesis. Administration of oral GSH leads to an increase in the concentration of L-cysteine, a precursor of GSH, in portal blood plasma. Oral administration of L-methionine produced a significant decrease of hepatic ATP in fasted rats, but not in fed rats. Administration of N-acetylcysteine or GSH did not affect the hepatic ATP levels. The results show that the oral intake of GSH is a safe and efficient form of administration of its constituent amino acids in cases when GSH synthesis is required to replete hepatic GSH levels.
TL;DR: Autoradiographically labelled cells were observed in the olfactory bulbs of perinatal, young and adult specimens of the lizard Podarcis hispanica following intraperitoneal injection of tritiated thymidine and found in the granular layer of both main and accessory bulbs.
TL;DR: In this article, a generalization of a previous group manifold quantization formalism is proposed, in which discrete transformations in the group are allowed, and a nonabelian group replaces the ordinary (central)U(1) subgroup of the Heisenberg-Weyl-like quantum group.
Abstract: A generalization of a previous group manifold quantization formalism is proposed. In the new version the differential structure is circumvented, so that discrete transformations in the group are allowed, and a nonabelian group replaces the ordinary (central)U(1) subgroup of the Heisenberg-Weyl-like quantum group. As an example of the former we obtain the wave functions associated with the system of two identical particles, and the latter modification is used to account for the Virasoro constraints in string theory.
TL;DR: In this article, a kinetic-spectrophotometric study is performed on the formation and degradation of the isoindole derivatives of amino acids with o-phthalaldehyde and N-acetyl-L-cysteine.
TL;DR: Qualitative and quantitative studies were performed on Vibrio species from seawater and mussel samples at a hatchery in Valencia harbour, and from market mussels, finding the most abundant species were V. harveyi and V. alginolyticus and the pathogenic species were recovered in very low numbers.
TL;DR: The results suggest that there are differences among countries in the target risk-level of performance, however, the present findings imply that within each country all subjects (regardless of age and sex) tended to have the same targetrisk-level.
TL;DR: In this paper, the stability of the oxalato complexes of bis(2-pyridylcarbonyl)amidocopper(II) have been determined in DMSO and water in the light of thermodynamic and structural parameters.
TL;DR: The dynamics of fungi, yeasts, and lactic acid bacteria during fermentation of four musts were studied and fungi disappeared quickly in the fermenting must and Yeasts grew quickly, reaching maximum populations at different times depending on the vinification treatment.
Abstract: The dynamics of fungi, yeasts, and lactic acid bacteria during fermentation of four musts were studied. Fungi disappeared quickly in the fermenting must. The lactic acid bacteria population diminished during alcoholic fermentation, then they increased and performed malolactic fermentation. Yeasts grew quickly, reaching maximum populations at different times depending on the vinification treatment.