Showing papers by "National Autonomous University of Mexico published in 1983"
TL;DR: In this paper, a simplified version of the experimentally determined Poincare map is proposed, and several features of the bifurcations of this map are described, including phase locking, period doubling and period chaotic dynamics at different values of the stimulation parameters.
174 citations
TL;DR: Salvia divinorum is a perennial labiate used for curing and divination by the Mazatec Indians of Oaxaca, Mexico as mentioned in this paper, and the psychotropic effects the plant produces are compared to those of the other hallucinogens employed by Mazatecs, the morning glory, Rivea corymbosa L., Hallier f. and the psilocybin-containing mushrooms.
148 citations
TL;DR: Although intervention focused primarily on drinking behavior, the majority of other life problems also showed improvement at all follow-up points andRemission of life problems was associated with decreased alcohol consumption and relapse to smoking coincided with unremitted drinking.
102 citations
TL;DR: The results showed that the auditory stimulus increased PGO spike density during REM sleep and produced a spectacular increase in the duration of REM, while decreasing the latency of its appearance from the first P GO spike.
84 citations
TL;DR: No clear relationship between mounting and other activities could be established and this pattern was better defined in group A than in group B where the bull was present, although all activities were observed at some stage during the observation period.
80 citations
TL;DR: In this article, a multiple tilted "packs of cards" model was proposed for normal faults in which rotational deformation within the major blocks is accommodated by normal faulting on previously formed tension fractures, thus defining smaller blocks of second and third generation.
Abstract: A characteristic pattern of normal faults that we have studied in several regions illustrates successive geometries relating to increasing amounts of extension from 10–50% (Gulf of Suez, Egypt) to 50–100% (Western Gulf of California, Mexico) up to 200% (Southern Basin and Range, USA). Tension fractures formed at an early stage of extension have an essential role. The resulting structure is described as a multiple tilted "packs of cards" model in which rotational deformation within the major blocks is accommodated by normal faulting on previously formed tension fractures, thus defining smaller blocks of second and third generation.
78 citations
TL;DR: In this paper, the (J,K) = (1,1) inversion transition of ammonia in 10 sources of bipolar outflow and detected and mapped the emission in seven of them.
Abstract: The phenomenon of bipolar mass outflow in regions of star formation is an important phase in the early stages of stellar evolution In this paper we address observationally the nature of the focusing agent We searched the (J,K) = (1,1) inversion transition of ammonia in 10 sources of bipolar outflow and detected and mapped the emission in seven of them Since ammonia is a tracer of high-density gas, n(H/sub 2/)> or approx =5 x 10/sup 3/ cm/sup -3/, we conclude that bipolar molecular outflows are commonly associated with dense condensations These condensations have internal velocity dispersions larger than those of dark clouds; however, they are in approximate virial equilibrium The ammonia data show the correlation between internal velocity dispersion and cloud size and mass previously obtained from carbon monoxide observations The molecular condensations associated with the bipolar outflows are generally elongated and engulf the compact object suspected to be the source of energy of the system For nine sources where clear orientations could be assigned to both the major axis of the condensation and the direction of the outflow, we found seven cases where these axes were nearly perpendicular This suggests that these elongted clouds may be toroid-shaped with dimensionsmore » of tenths of parsecs and may provide the focusing mechanism in bipolar outflows In this model, the stellar wind of the central object has created a bipolar cavity in an originally pancake-shaped cloud The wind, which could be isotropic near the star, is stopped in the plane of the dense toroid but escapes along the poles, accelerating the surrounding lower density molecular gas« less
74 citations
TL;DR: It is shown that FTG cells are not essential for REM sleep, but that in non-lesioned cats its cholinergic activation may form part of a complex REM generating system.
65 citations
TL;DR: This paper showed that these isotope ratios are negatively correlated and lie on the mantle array defined by MORB and oceanic island rocks; implying that Los Humeros magmas were generated in the upper mantle with very little, if any, contribution from the subducted oceanic crust, sediments or continental crust.
Abstract: The Mexican volcanic belt (MVB), a roughly east–west structure, consists of many late Tertiary and Quaternary cindercones, domes, calderas and stratovolcanoes1,2. Los Humeros caldera (approximately 19°40′ N latitude, 97°25′ W longitude) lies on the northeastern part of the MVB where the belt overlaps with another major volcanic province, the Eastern cordillera3 (Fig. 1). A compilation6 of the bulk chemical analyses of the two major volcanic provinces indicates that the MVB is characterized largely by calc-alkaline series whereas rocks of the alkaline series dominate the Eastern cordiliera (EC). Pleistocene to Recent basaltic to rhyolitic volcanism in Los Humeros caldera, one of the best known examples of a well-developed caldera in Mexico7–9, presumably associated with the subduction of Cocos plate along the Middle America trench, shows that the initial 87Sr/86Sr ratios range from 0.7039 to 0.7048 and the initial 143Nd/144Nd ratios from 0.5126 to 0.5129. We show here that these isotope ratios are negatively correlated and lie on the mantle array defined by MORB and oceanic island rocks; implying that Los Humeros magmas were generated in the upper mantle with very little, if any, contribution from the subducted oceanic crust, sediments or continental crust.
62 citations
62 citations
TL;DR: It appears that during the process of liver regeneration which follows partial hepatectomy there is a transition in the type of adrenergic receptor involved in the hepatic actions of catecholamines from β in the initial stages to later α 1, a similar transition seems to occur as the animal ages.
TL;DR: Administration of purified pertussis toxin to rats induced persistent tachycardia and markedly diminished the pressor effect of the alpha 2-adrenergic agonists clonidine and azepexole, suggesting a role of adenylate cyclase inhibition in the action of postsynaptic vascularalpha 2- adrenergic receptors.
TL;DR: Histopathological studies showed that more than 40% of larvae obtained from immunized hogs were completely destroyed and the others were seen in various stages of degeneration.
TL;DR: A methodology for the detection of emerging paradigms is developed through the analysis of implicit and explicit criticisms and reveals a set of systems frames at different stages of development.
Abstract: A methodology for the detection of emerging paradigms is developed through the analysis of implicit and explicit criticisms. The search for the systems' paradigm reveals a set of systems frames at different stages of development. Four basic assumptions that underlie most systems frames and limit their use in the research, design, planning, and management of social systems are identified. A set of frames that may advance the systems movement are proposed. They are enclosed under the name of systemic-netfields and provide a link between systems and networks, aggregates, and fields.
01 Jan 1983
TL;DR: A survey of pathogenic and free-living amoebae in swimming pool waters of Mexico City was performed and it was shown that the free residual chloride values of 0.50 to 1.5 mg/liter, ordinarily used in pool waters, are not adequate for elimination of amoEBae.
TL;DR: Tambourissa exhibits an unusual spectrum of floral diversity, tightly linked, however, by a common ground plan, and extraordinary evolutionary trends include the differentiation of a hyperstigma, the carpel group formation within a gynoecium, the increasing disorder in carpel orientation with increase of carpel number.
Abstract: Tambourissa exhibits an unusual spectrum of floral diversity, tightly linked, however, by a common ground plan. Divergent evolutionary trends have led to small, closed flowers and to secondarily open flowers, including the largest of theMonimiaceae. The myophilous and cantharophilous flowers attract pollinators by scent, colour, stigmatic nectar and pollen. Some species have attained monoecy with partial or complete self-incompatibility, others even dioecy. Extraordinary evolutionary trends include the differentiation of a hyperstigma, the carpel group formation within a gynoecium, the increasing disorder in carpel orientation with increase of carpel number, and the formation of a pseudoperianth by the sterile lobes of the floral cup.
TL;DR: The littoral lagoons of the Gulf of Mexico have been investigated to determine the amount of heavy metal pollution as discussed by the authors, and it was found that oysters are able to concentrate metals, mainly Cd and Pb above the maximum permissible limits for edible consumption.
Abstract: The littoral lagoons of the Gulf of Mexico have been investigated to determine the amount of heavy metal pollution. Some lagoons have been contaminated by liquid wastes mainly originating from sugar refining and petrochemical industries, as well as petroleum exploitation and refining. Since mollusks concentrate trace elements, determination of levels of Cd, Cr, Hg, and Pb in oysters (Crassostrea virginica) were measured in some of these lagoons. The results have shown that the concentrations of these metals in lagoon water were below the recommended levels to protect aquatic life, and it was found that oysters are able to concentrate metals, mainly Cd and Pb above the maximum permissible limits for edible consumption.
TL;DR: 4 amebicides and 6 anthelmintics tested for mutagenicity in the Salmonella typhimurium microsomal test system induced frameshift and base-pair substitution mutations with or without metabolic activation, and urine of mice treated with dehydroemetine or pyrvinium pamoate showed no mutagenic activity.
Abstract: 4 amebicides (chloroquine diphosphate, diiodohydroxyquin, iodochlorohydroxyquin and dehydroemetine) and 6 anthelmintics (bephenium hydroxynaphthoate, 4-hexylresorcinol, mebendazole, niclosamide, pyrantel pamoate and pyrvinium pamoate) were tested for mutagenicity in the Salmonella typhimurium microsomal test system. Frameshift mutations were induced by dehydroemetine and niclosamide following activation by microsomal enzymes, while pyrvinium pamoate induced both frameshift and base-pair substitution mutations with or without metabolic activation. The urine of mice treated with dehydroemetine or pyrvinium pamoate showed no mutagenic activity. However, urine obtained from mice treated with niclosamide was mutagenic in strains TA98 and TA1538. The fluctuation assay showed chloroquine diphosphate to be mutagenic in TA1537, a strain which detects frameshift mutations.
TL;DR: The visible wavelength optical properties of the ash from the 1982 El Chichon eruptions are measured using ash samples collected at three surface sites at distances between 12 and 80 km from the volcano as discussed by the authors.
Abstract: The visible wavelength optical properties of the ash from the 1982 El Chichon eruptions are measured using ash samples collected at three surface sites at distances between 12 and 80 km from the volcano. The most distant sample is assumed to be the most representative of the silicate ash injected into the stratosphere. The measured optical properties are presented as a complex refractive index n, while the aerosol absorption is expressed as the imaginary component of the refractive index, n sub IM. Results show that each of these samples exhibited low values of absorption, with n sub IM at 500 nm ranging from 0.0015 for the 12 km sample to 0.001 for the 80 km sample. Based on these measurements, it is estimated that n for the stratospheric silicate ash is given by n = 1.53 - 0.001i.
TL;DR: Turning induced by apomorphine in rats lesioned with 6-hydroxydopamine is inhibited by damage to the ipsilateral ventromedial area of thalamus which receives fibres from the substantia nigra.
Abstract: The Playa Azul earthquake broke the central part of the Michoacan gap along the Mexican subduction zone. The aftershock area estimated from field data for a 6-day period beginning 19 hr after the main shock is 40 km × 20 km. Preliminary focal mechanism of the main shock is consistent with a shallow-dipping thrust fault. Although there is some evidence of seismic quiescence for 5 1 2 yr followed by a foreshock about 3 months before the main shock and an above average microseismic activity in the western part of the epicentral region during the last 4 1 2 months or more, the data is not sufficient quality to assert this conclusion. The Michoacan gap was previously assigned category 3 (Singh et al. , 1981) based on the classification of McCann et al. (1979). The seismic potential of the unbroken segments of this gap (∼45 km to NW and ∼35 km to the SE of the Playa Azul aftershock area) remains uncertain. Corresponding to a rupture length of 40 km, each segment could generate an earthquake of similar magnitude to the Playa Azul earthquake. Unfortunately, the recurrence period of large earthquakes in the region is not known and great/major earthquakes cannot be ruled out.
01 Jan 1983
TL;DR: The results suggest that liver purine metabolism might participate in the maintenance and renewal of the blood purine pool and in the energy state of erythrocytes in vivo.
TL;DR: In this article, power spectral analysis has been applied to the Zurich sunspot series and the results indicate that the next 60 yr will be characterized by a relatively low sunspot activity.
Abstract: Application of the non-integer technique of power spectral analysis has yielded evidence for long-term periodicities in the Zurich sunspot series. Although the spectrum shows significant power in the wavelength range 9 to 12 yr, additional peaks corresponding to cycle lengths within the ranges 80–100 and 170–180 yr are also found to be significant. The reality of these peaks is tested extending the historical record into an independent future period. The results indicate that the next 60 yr will be characterized by a relatively low sunspot activity.
TL;DR: In this article, the authors show that the lower bound on a continuous energy spectrum suffices t⊙ mathematically preclude the construction of a hermitian time operator canonically conjugate to the Hamiltonian.
TL;DR: Quantitative immunoelectrophoresis established that, under all conditions, enzyme activity corresponded to enzyme concentration, and isotope incorporation studies demonstrated that the nitrogen source exerts its regulation at the level of de novo enzyme synthesis.
Abstract: Neurospora crassa glutamate dehydrogenase-NADP (EC 1.3.1.3) has a higher activity when mycelium is grown on ammonium or nitrate as nitrogen source than when grown on glutamate or glutamine. Quantitative immunoelectrophoresis established that, under all conditions, enzyme activity corresponded to enzyme concentration. Isotope incorporation studies demonstrated that the nitrogen source exerts its regulation at the level of de novo enzyme synthesis.
TL;DR: According to behavioral comparisons, the coastal population of the garter snake Thamnophis elegans has retained all the elements of its aquatic foraging repertoire, but its tendencies to perform them have diminished.
Abstract: Behavioral comparisons were made of two populations of the garter snake Thamnophis elegans: a typical population with semi-aquatic habits and diet (inland population), and a coastal population that has entered a terrestrial feeding niche. Laboratory-born snakes of both populations were compared for their tendency to eat fish and their aquatic foraging behavior.
TL;DR: The results suggest that internal Ca2+, by inducing a lowering of the internal concentration of adenine nucleotides, diminishes the rate of exchange ofadenineucleotides via the translocase, and in consequence of oxidative phosphorylation.
TL;DR: The absence of GSSG-reductase activity in organisms lacking GSH, confirms that glutathione metabolism is not universal and suggests that this enzyme might be useful as a marker in classifying organisms.
Abstract: The disulfide reducing activities of GSSG-and CoASSG-reductases were measured on partially purified extracts from a variety of prokaryotes and eukaryotes.