Showing papers by "University of Nevada, Reno published in 1988"
TL;DR: Little is known at the biochemical level about the regulation of fatty acid metabolism, and it is suggested that work in this area represents another frontier in insect biochemistry.
Abstract: The composition, metabolism, and significance of fatty acids in insect biology are addressed. Fatty acids enter a number of metabolic pathways not directly related to energy storage and production; the unifying theme is that the fatty acids are not only structurally altered in these pathways, but that the alterations carry them from one area of biological significance into another. This theme is developed by offering a perspective on fatty acids in insects and then reviewing three major areas: 1) fatty acid composition, 2) biosynthesis of fatty acids (including polyunsaturated fatty acids and characteristics of certain biosynthetic enzymes), and 3) the biological significance of fatty acids. This last section includes discussions of the biochemistry of waxes, pheromones, and prostaglandins and the roles of fatty acids as components of defensive secretions. Little is known at the biochemical level about the regulation of fatty acid metabolism, and it is suggested that work in this area represents another frontier in insect biochemistry.
435 citations
TL;DR: Eight adult humans were taught conditional discriminations in a matching-to-sample format that led to the formation of two four-member equivalence classes, which may contribute to a behavior-analytic approach to semantics and generative grammar.
Abstract: Eight adult humans were taught conditional discriminations in a matching-to-sample format that led to the formation of two four-member equivalence classes. When subjects were taught to select one comparison stimulus from each class in a set order, they then ordered all other members of the equivalence classes without explicit training. When the ordering response itself was brought under conditional control, conditional sequencing also transferred to all other members of the two equivalence classes. When the conditional discriminations in the matching-to-sample task were brought under higher order conditional control, the eight stimulus members were arranged into four conditional equivalence classes. Both ordering and conditional ordering transferred to all members of the four conditional equivalence classes; for some subjects this occurred without a typical test for equivalence. One hundred twenty untrained sequences emerged from eight trained sequences for all subjects. Transfer of functions through equivalence classes may contribute to a behavior-analytic approach to semantics and generative grammar.
381 citations
TL;DR: To answer questions about the philosophy underlying behavior analysis compared to those of other perspectives, it is necessary to be clear about the assumptions and postulates of the position that are not deliberately and unambiguously laid down.
Abstract: Behavior analysis has always had significant conflicts with other psychological perspectives. At their most fundamental level, these conflicts are often philosophical, concerning such issues as the nature of the human and the purposes of science. Why are these the conflicts? What, if anything, can we do about them? Can we resolve them? Can we avoid them altogether by simply abandoning philosophy? To answer these questions, we must be clear about the philosophy underlying behavior analysis compared to those of other perspectives. To be clear is difficult, however, because the assumptions and postulates of the position are not deliberately and unambiguously laid down. Fundamental assumptions, specific theories, and historical accidents are too often discussed concurrently and without adequate differentiation in behavior-analytic expositions. Skinner's philosophical writings are especially prone to this difficulty, perhaps because he is so extensively involved with so many nonphilosophical aspects of the field. In 1942 Stephen C. Pepper, a philosopher and aestheticist, published World Hypotheses: A Study in Evidence. His central insight was that philosophical systems cluster around a few core models, or \"world hypotheses,\" drawn from common sense. His strategy was to ignore details and personalities, and instead to present the central tenets of each world view in a general way. He used his own terms to describe most of these tenets, avoiding excess or parochial meanings. He quoted and cited very little. His style permits an understanding of
266 citations
TL;DR: The study analyzes 16 magnet hospitals to ascertain to what extent they possess characteristics similar to the 'best run' companies in the corporate community and suggests that these magnet hospitals may be dealing effectively with the nursing shortage.
Abstract: The oft repeated charge today is "focus on those who are succeeding!" That's what this report does. Using the eight characteristics identified by Peters and Waterman in their book In Search of Excellence (New York: Harper & Row, 1982), the study analyzes 16 magnet hospitals to ascertain to what extent they possessed characteristics similar to the best run companies in the corporate community. Analysis indicates many areas of strong correspondence. The authors suggest that these magnet hospitals may be dealing effectively with the nursing shortage by creating organizational conditions conducive to eliminating internal nurse shortage.
221 citations
TL;DR: For a series of 3,5,7-trihydroxyflavones that differed by b-ring hydroxylation it was found that decreasing E 1/2 of the flavonoids was associated with decreasing I50 values towards succinoxidase, suggesting that the electrochemical properties of the Flavonoids may contribute to their biological activity.
213 citations
TL;DR: In this article, hundreds of non-cultural elephant bone sites have been studied in southern Africa, starting at or before the actual moments of death and continuing through bone burial or destruction.
141 citations
TL;DR: The findings indicate that prejunctional purinoceptors that mediate an inhibition of the release of noradrenaline from the adrenergic nerves of the caudal artery may not be adequately defined as either P1- or P2-receptors and thus appear to represent a unique receptor.
Abstract: The effects of a number of purinoceptor agents on the release of endogenous noradrenaline from the electrically stimulated rat caudal artery were determined. Noradrenaline was quantified by high performance liquid chromatography-electrochemical detection techniques. Both P1-receptor and P2-receptor agonists reduced the release of noradrenaline; the relative order of potency being 2-chloroadenosine greater than beta, gamma methylene ATP greater than ATP greater than or equal to adenosine. The adenosine uptake inhibitor S-p-nitro-benzyl-6-thioguanosine potentiated the effects of adenosine but not those of the adenine nucleotides. This suggests that the nucleotides do not need to be converted to adenosine to produce a prejunctional inhibition of the release of noradrenaline. The P1-receptor antagonist 8-(p-sulfophenyl) theophylline reduced the inhibitory effects of both P1- and P2-receptor agonists as did the photolysis of tissues with an intense light source. The findings indicate that prejunctional purinoceptors that mediate an inhibition of the release of noradrenaline from the adrenergic nerves of the caudal artery may not be adequately defined as either P1- or P2-receptors and thus appear to represent a unique receptor. We suggest referring to these receptors as P3-purinoceptors.
124 citations
TL;DR: A comparison of systems analysis techniques, the Data Flow Diagram (DFD) and part of the Integrated Definition Method (IDEFo) is done using a new developmental framework.
Abstract: A comparison of systems analysis techniques, the Data Flow Diagram (DFD) and part of the Integrated Definition Method (IDEFo), is done using a new developmental framework.
116 citations
TL;DR: Longitudinal studies of bone sites in Africa and Canada indicate that both mass death sites and sites of serial predation share many significant characteristics, such as dense bone deposits, representation of multiple taxa, presence of different degrees of gnaw-damage and different weathering stages, and concise spatial areas containing the bones.
113 citations
TL;DR: Responses to browsing by trees place constraints on the predictive value of standard energy-based optimal foraging models, and limitations on the use of such models are shown.
Abstract: At a newly occupied pond, beavers preferentially felled aspen smaller than 7.5 cm in diameter and selected against larger size classes. After one year of cutting, 10% of the aspen had been cut and 14% of the living aspen exhibited the juvenile growth form. A phenolic compound which may act as a deterrent to beavers was found in low concentrations in aspen bark, and there was no significant regression of relative concentration of this compound on tree diameter. At a pond which had been intermittently occupied by beavers for over 20 years, beavers selected against aspen smaller than 4.5 cm in diameter, and selected in favor of aspen larger than 19.5 cm in diameter. After more than 28 years of cutting at this site, 51% of the aspen had been cut and 49% of the living aspen were juvenileform. The phenolic compound was found in significantly higher concentrations in aspen bark than at the newly occupied site, and there was a significant negative regression of relative concentration on tree diameter. The results of this study show that responses to browsing by trees place constraints on the predictive value of standard energy-based optimal foraging models, and limitations on the use of such models. Future models should attempt to account for inducible responses of plants to damage and increases in concentrations of secondary metabolites through time.
105 citations
TL;DR: It is shown that incubation of encapsulated cryptococci in normal human serum leads to deposition of large amounts of C3 fragments at the surface of the yeast and lesser amounts of IgG within the capsule, and the capsule mediates two biologic activities with opposing effects.
Abstract: The capsule is closely associated with the virulence of Cryptococcus neoformans. The capsule inhibits phagocytosis by macrophages, monocytes, and neutrophils. Studies in our laboratory have shown that incubation of encapsulated cryptococci in normal human serum leads to deposition of large amounts of C3 fragments at the surface of the yeast and lesser amounts of IgG within the capsule. Thus, the capsule mediates two biologic activities with opposing effects. It is our current view that phagocytosis of the yeast is dependent on a balance between the antiphagocytic action of cryptococcal polysaccharide and the ability of the yeast to focus opsonically active complement fragments and the IgG at the capsular surface.
TL;DR: In this paper, height and time-dependent snow growth models were developed for unrimed stratiform snowfall, where moment conservation equations were parameterized and solved by constraining the size distribution to be of the form N(D)dD = N0 exp(−&lambdaD)D, yielding expressions for the slope parameter, λ, and the y-intercept parameters, NO, as functions of height or time.
Abstract: Based on the stochastic collection equation, height- and time-dependent snow growth models were developed for unrimed stratiform snowfall. Moment conservation equations were parameterized and solved by constraining the size distribution to be of the form N(D)dD = N0 exp(−&lambdaD)dD, yielding expressions for the slope parameter, λ, and the y-intercept parameters, NO, as functions of height or time. The processes of vapor deposition and aggregation were treated analytically without neglecting changes in ice crystal habits, while the ice particle breakup process was dealt with empirically. The models were compared against vertical profiles of snow-size spectra, obtained from aircraft measurements, for three case studies. The predicted spectra are in good agreement with the observed evolution of snow-size spectra in all three cases, indicating the proposed scheme for ice particle aggregation was successful. The temperature dependence of aggregation was assumed to result from differences in ice cryst...
TL;DR: The same-signed CD spectra shared by all the pigments of this work indicate selection at the protein binding site for a positive chirality conformer and suggest a common binding site, consistent with a binding model where one salt linkage plays a major role in the enantioselectivity of the right-handed folded conformation stabilized by inter- and intramolecular hydrogen bonds.
TL;DR: Four consistent and distinct cuticular hydrocarbon patterns, or chemical phenotypes, were identified from the three described species of Zootermopsis, and should alert systematists and others to a major concern.
Abstract: Colonies ofZootermopsis were collected from the central Sierra Nevada and the Monterey Penninsula in California, and from southern Arizona. Cuticular hydrocarbons were identified by gas chromatography-mass spectrometry (GC-MS) and quantified by gas-liquid chromatography (GLC) for each caste of all colonies. Four consistent and distinct cuticular hydrocarbon patterns, or chemical phenotypes, were identified. Unique and abundant monomethyl- and dimethylalkanes, and ann-alkene provided easy separation of the various phenotypes. Significant differences in the proportions of the various components were found among castes within a colony and colonies within phenotypes from California. Differences in the hydrocarbon proportions for castes were not consistent between colonies. The current taxonomy of the genusZootermopsis recognizes three species. Our identification of four consistent, unique cuticular hydrocarbon phenotypes from the three described species should alert systematists and others to a major concern. If there are truly only three extant species, then the hypothesis that cuticular hydrocarbon profiles in this genus are species specific is not acceptable. Conversely, if cuticular hydrocarbon profiles are truly species specific, then there is at least one new, undescribed species ofZootermopsis.
TL;DR: In this article, the ability of three internal markers to predict dry matter digestibility and two external markers to estimate faecal output was evaluated in a completely random design to evaluate the ability for the three internal marker estimates and external marker estimates.
Abstract: Twenty fine-wool, ruminally cannulated lambs (average weight 45–9 kg) were used in a completely random design to evaluate the ability of three internal markers to predict dry matter digestibility and two external markers to estimate faecal output. Lambs were allotted randomly to one of four diets: 100% prairie hay (PH), 100% lucerne hay (LH), 50% prairie hay:50% sorghum grain (PS) and 50% lucerne hay: 50% sorghum grain (LS). The trial consisted of a 14-day adaptation period followed by a 7-day total faecal collection period. Feed and faecal samples were subjected to 96 h ruminal fluid and 48 h acid-pepsin digestions, followed by extraction with acid detergent (IVADF) or neutral detergent (IVNDF) solution. Dry matter digestibility (DMD) calculated from feed:faeces ratios of IVADF, IVNDF and acid detergent lignin (ADL) was compared with in vivoapparent digestibility. Ytterbium-labelled forage (YLF) and dysprosium-labelled faeces (DLF) were pulse-dosed via ruminal cannulae, and faecal Yb and Dy excretion curves were fitted to a one-compartment, agedependent model for estimation of faecal output, paniculate passage rate (PPR) and mean gastrointestinal retention time. In vivoDMD in lambs fed PH was greater (P 005) from marker estimates. In vivoDMD for lambs fed PS did not differ from IVNDF or IVADF estimates but was greater than (P 005) were observed in recovery among the three internal markers for any of the diets. Faecal output for lambs fed PH did not differ {P >005) from marker estimates but was overestimated by 15 to 20% by YLF and DLF. Faecal output for lambs fed LH was similar to the estimate from YLF, but less than (P <0–05) the estimate with DLF. For lambs fed PS, faecal output did not differ from marker estimates, but YLF and DLF values were 16% lower and 17% higher, respectively. No significant differences were observed in actual and estimated faecal output for lambs fed the LS diet. Estimates of PPR with DLF were numerically greater than YLF estimates for all diets except LS. Correspondingly, mean gastrointestinal retention time was less (P <005) for DLF compared with YLF for all diets except LS.
TL;DR: The slow rate of activity loss by Rubisco in this species suggests a biochemical basis for the increased efficiency for CO(2) assimilation of successive lightfleck use by species such as A. macrorrhiza.
Abstract: The regulation of ribulose-1,5-bisphosphate (RuBP) carboxylase (Rubisco) activity and pool sizes of RuBP and P-glycerate were examined in the tropical understory species Alocasia macrorrhiza following step changes in photon flux density (PFD). Previous gas exchange analysis of this species following a step increase in PFD from 10 to 500 micromoles quanta per square meter per second suggested that the increase in photosynthetic rate was limited by the rate of increase of Rubisco activity for the first 5 to 10 minutes. We demonstrate here that the increase in photosynthetic rate was correlated with an increase in both the activation state of Rubisco and the total kcat (fully activated specific activity) of the enzyme. Evidence presented here suggests that a change in the pool size of the naturally occurring tight binding inhibitor of Rubisco activity, 2-carboxyarabinitol 1-phosphate, was responsible for the PFD-dependent change in the total kcat of the enzyme. RuBP pool size transiently increased after the increase in PFD, indicating that photosynthesis was limited by the capacity for carboxylation. After 5 to 10 minutes, RuBP pool size was again similar to the pool size at low PFD, presumably because of the increased activity of Rubisco. Following a step decrease in PFD from 500 to 10 micromoles quanta per square meter per second, Rubisco activity declined but at a much slower rate than it had increased in response to a step increase in PFD. This slower rate of activity decline than increase was apparently due to the slower rate of 2-carboxyarabinitol 1-phosphate synthesis than degradation and, to a lesser degree, to slower deactivation than activation. RuBP pool size initially declined following the decrease in PFD, indicating that RuBP regeneration was limiting photosynthesis. As Rubisco activity decreased, RuBP slowly increased to its original level at high PFD. The slow rate of activity loss by Rubisco in this species suggests a biochemical basis for the increased efficiency for CO2 assimilation of successive lightfleck use by species such as A. macrorrhiza.
TL;DR: Phagocytosis of Cryptococcus neoformans is markedly influenced by the presence of a polysaccharide capsule and activation of the complement cascade is necessary but not sufficient for phagocyTosis of the yeast cell.
Abstract: Phagocytosis of Cryptococcus neoformans is markedly influenced by the presence of a polysaccharide capsule. We examined activation and binding of C3 fragments to eight isolates of C. neoformans. All isolates were shown to have capsules by light and electron microscopy. These strains differed in susceptibility to phagocytosis by neutrophils. Yeast cells were opsonized by incubation in normal human serum. Five strains were resistant to ingestion, two strains showed intermediate levels of resistance to ingestion, and one strain was quite sensitive to phagocytosis. Yeast cells opsonized with heat-inactivated serum (56 degrees C for 30 min) neither attached nor were ingested by neutrophils. A quantitative estimate of the amount of C3 bound to the yeast cells was determined by use of normal human serum containing 125I-labeled C3. The results showed approximately 5 X 10(6) to 10 X 10(6) C3 molecules per yeast cell regardless of whether the yeast cells were sensitive or resistant to phagocytosis. Bound C3 was eluted from the yeast cells by treatment with 0.1 M NH2OH (pH 10), and the eluted fragments were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions. Results of this analysis showed that little of the C3 was in the form of C3b, and there was substantial decay to iC3b, the inactive decay product of C3b. This pattern of decay was similar with all strains. Immunoelectron microscopy was used to assess the ultrastructural location of the C3 fragments bound to the yeast cells. C3 fragments were bound to the perimeter of the capsule regardless of whether the isolate was sensitive or resistant to phagocytosis. Thus, phagocytosis-sensitive and phagocytosis-resistant isolates were similar with regard to the amount, molecular form, and ultrastructural location of C3 fragments bound to the cryptococcal capsule. These results further indicate that activation of the complement cascade is necessary but not sufficient for phagocytosis of the yeast cell.
TL;DR: Using enzyme preparations of mid-fifth instar larvae of the cabbage looper moth, Trichoplusia ni, the GSH-dependent peroxidase activity appears to conform to the peroxIDase activity analogous to the mammalian non-Se glutathione transferase.
TL;DR: Microanalyses of unstructured videotaped interactions of three mother-infant dyads revealed dramatic shifts in dyadic vocalization patterns from primarily overlapping to primarily alternating, linked to the concomitant development of multimodal sensory-sensory and sensory-motor integration.
Abstract: Microanalyses of unstructured videotaped interactions of three mother-infant dyads revealed dramatic shifts in dyadic vocalization patterns from primarily overlapping to primarily alternating. Maximal overlapping vocalization appeared between 7 and 13 weeks for the different dyads, and subsequent alternation predominance peaked between 12 and 18 weeks. The findings are compared with prior work which had not found alternation predominance and reasons for the difference are suggested. The early emergence of a sequence of predominantly overlapping vocalization followed by predominantly alternating vocalization may be linked to the concomitant development of multimodal sensory-sensory and sensory-motor integration. If so, then the emergent patterns reflect increased potential for co-ordination within the dyad, which may be capitalized upon by the mother and by the infant.
TL;DR: The studies point out the key role that the antioxidant enzymes play in insect defenses against plant prooxidants.
Abstract: The black swallowtail butterfly larvae, Papilio polyxenes, are specialist feeders that have adapted to feeding on plants containing high levels of prooxidant allelochemicals. Third, fourth, and fifth instar larvae were tested for their antioxidant enzyme activities, superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and glutathione peroxidase (GPOX), using 850-g supernatants from whole-body homogenates. The overall antioxidant enzyme profile for P. polyxenes was high compared to other insects, with activities ranging as follows: SOD, 1.1–7.5; CAT, 124–343; GR, 1.0–7.5; and GPOX, 0 units.
To determine whether these antioxidant enzymes were inducible, P. poly xenes larvae were given a prooxidant challenge by dipping parsley leaves (their diet in the initial studies) in solutions of quercetin, such that the leaves became coated with this prooxidant flavonoid. Mid-fifth instar larvae fed on quercetin-coated leaves were assayed for antioxidant enzyme activities as was previously done with the larvae fed the standard diet. Food consumption and quercetin intake were monitored. SOD activity was increased almost twofold at the highest quercetin concentration tested. CAT and GR activity, on the other hand, were inhibited by increased quercetin consumption, with GR activity completely inhibited at the highest quercetin concentration after 12 h of feeding. GPOX activity, not present in control insects, was also not inducible by a quercetin challenge. These studies point out the key role that the antioxidant enzymes play in insect defenses against plant prooxidants.
TL;DR: The results of these studies are consistent with the hypothesis that slow-wave propagation across the circular layer in canine proximal colon occurs passively, suggesting the latter are due to a different mechanism than depolarization.
Abstract: The effects of membrane potential on the waveforms and propagation of slow waves were tested using circular muscles of the canine colon. Studies were conducted with intracellular recording techniqu...
TL;DR: The results indicate that plant species may differ markedly in the mechanisms they use to regulate RbuP(2) carboxylase activity as PPFD changes, and suggest that tight binding inhibitors are a more widespread mechanism for regulation of this enzyme than previously thought.
Abstract: The mechanisms involved in the in vivo light-dependent regulation of ribulose-1,5-bisphosphate (RbuP2) carboxylase [3-phospho-D-glycerate carboxy-lyase (dimerizing), EC 4.1.1.39] activity in intact leaves were studied. In the three species examined, Phaseolus vulgaris, Beta vulgaris, and Spinacea oleracea, the regulated level of RbuP2 carboxylase activity (assayed in vitro with saturating substrate) was highly correlated (r = 0.96) with the rate of net CO2 uptake of the corresponding leaves measured over a wide range of photosynthetic photon flux density (PPFD). However, the mechanisms by which the enzyme was regulated differed between these species. In Phaseolus, the inhibitor 2-carboxyarabinitol 1-phosphate (CAP) accounted for all of the PPFD-dependent regulation of RbuP2 carboxylase activity. A similar compound was detected in Beta, and changes in its concentration accounted for about half of the PPFD-dependent regulation of enzyme activity in this species. No CAP was detected in Spinacea, but evidence we obtained suggests that a different inhibitor (possibly RbuP2) accounts for a significant portion of the PPFD-dependent regulation of enzyme activity in this species. Changes in the activation state of the enzyme were observed with Beta and Spinacea, while in Phaseolus the enzyme was apparently fully activated at all PPFD levels. These results indicate that plant species may differ markedly in the mechanisms they use to regulate RbuP2 carboxylase activity as PPFD changes. The results also suggest that tight binding inhibitors are a more widespread mechanism for regulation of this enzyme than previously thought. Furthermore, the results establish the importance of such inhibitors in regulating both the activity of RbuP2 carboxylase and whole leaf photosynthesis over a range of PPFD.
TL;DR: There were differences noted in the performance of the three groups, which included differences related to language maturity as well as differences specific to language condition.
Abstract: This study compared the conversational repair strategies employed by 8 language-impaired children (mean chronological age 9:2 years) and their linguistically normal age- and language-matched peers ...
TL;DR: In this article, the authors examined the readiness with which equivalence classes can be formed involving gustatory stimuli, as compared with visual stimuli, and found that equivalence class eventually formed for all subjects.
Abstract: The present study examines the readiness with which equivalence classes can be formed involving gustatory stimuli, as compared with visual stimuli. In Experiment 1, two groups of normal adults were taught either visual-visual conditional discriminations or gustatory-visual conditional discriminations and were then tested to determine if classes of equivalent stimuli had formed. Equivalence classes eventually formed for all subjects. Gustatory-visual conditional discriminations required fewer training trials and equivalence classes based on these discriminations emerged in testing with fewer errors than was the case with visual stimuli. These findings were replicated within subjects in Experiment 2.
TL;DR: A large body of evidence demonstrates that the results of operant conditioning appear regardless of and often in spite of response-contingent consequences, and there appears to be a fundamental logical defect in all contingency models of the learning process.
Abstract: The view that learning is governed by positive and negative consequences has dominated theory and application throughout this century. In some systems stimulus-response connections are stamped in or stamped out by the consequences of action, in others, cognitive expectancies are formed by experience with past consequences. The evidence from early experiments with rats and pigeons and the feedback principles of early servomechanisms seemed to offer both hard evidence and a plausible model for the law of effect in either its behaviorist or its cognitive form.A large body of evidence demonstrates that the results of operant conditioning appear regardless of and often in spite of response-contingent consequences. Experiments designed to measure a residual effect of consequences exhibit an inevitable ex post facto error that vitiates all possible versions of this experimental design. Experiments designed to measure the effect of predictive contingency in Pavlovian conditioning exhibit a corresponding error. There appears to be a fundamental logical defect in all contingency models of the learning process.Meanwhile, modern developments in ethology and computer science provide a unified feedforward model of the learning of adaptive and maladaptive behavior under both laboratory and field conditions. Because the feedforward model is more parsimonious, it is also more compatible with Darwinian principles of biological economy. Research on teaching new and challenging tasks to freeliving, well-fed subjects such as children and cross-fostered chimpanzees illustrates the wide applicability and practical effectiveness of feedforward.
TL;DR: This paper described the United States as a stream of controversies with little attention to the history or human side of the new, new, religions, and pointed out that "naws about "cults" in America are clearly information by outsiders for outsiders and, although not uniformly negative, can best be described as "a stream of controversy" with few attention to human side.
Abstract: Naws about “cults” in the United States is clearly information by outsiders for outsiders and, although not uniformly negative, can best be described as “a stream of controversies” with little attention to the history or human side of the new, religions
TL;DR: In this article, the author adds a second level to clarify the stages of forming, storming, norming, performing, and adjourning of group work, and this level is used to clarify Tuckman's theory of group development.
Abstract: Graduate students in group work find Tuckman's theory of the stages of group development too limiting. In this article the author adds a second level to clarify the stages of forming, storming, norming, performing, and adjourning.
TL;DR: The Guerrero digital accelerograph network has been operating, since spring of 1985, on rock sites along the coast of Mexico, above an active subduction zone, and the accelerograms collected through June 1987 include examples from events with magnitudes from 3 to 8, all recorded at nearly the same hypocentral distance as mentioned in this paper.
Abstract: The Guerrero digital accelerograph network has been operating, since spring of 1985, on rock sites along the coast of Mexico, above an active subduction zone. The accelerograms collected through June 1987 include examples from events with magnitudes from 3 to 8, all recorded at nearly the same hypocentral distance. Spectra from these accelerograms scale in a manner that is qualitatively consistent with earthquake source theory. Based on four selected events, peak accelerations attenuate more rapidly for small events than for large events.
TL;DR: It was demonstrated that both the respiratory bursts and the autoxidation result in the production of superoxide (O2‒) and hydrogen peroxide (H2O2) in isolated beef heart mitochondrial preparations.
Abstract: Catechols and other polyphenolic compounds have been shown to autoxidize and generate reactive oxygen species. A few examples of such compounds include epinephrine, 6-hydroxydopamine,2 and pyrogallol.3 We have previously reported that members of a class of polyphenolics, the flavonoids (Figure 1), behave in a similar manner. In particular four flavonoids, myricetin (3,5,7,3’,4’,5’-hexahydroxyflavone), quercetagetin (3,5,6,7,3’,4’-hexahydroxyflavone), delphinidin chloride (3,5,7,3’,4’,5’-hexahydroxyflavylium chloride) and quercetin 3,5,7,3’4’-pentahydroxy-flavone) induce cyanide-insensitive respiration in isolated beef heart mitochondrial preparations. Additionally, these compounds autoxidize in aqueous solutions at pH 7.5, as determined by measuring oxygen consumption and oxygen-dependent spectral changes. It was demonstrated that both the respiratory bursts and the autoxidation result in the production of superoxide (O2‒) and hydrogen peroxide (H2O2).4