Showing papers by "University of Georgia published in 1983"

Job satisfaction: are all the parts there?

Abstract: Empirical data indicate that global measures of job satisfaction are not equivalent to the sum of the facet satisfactions. The purposes of this study were to explore the usefulness of single-item global measures of job satisfaction for job satisfaction research and also to explore whether global assessments of job satisfaction include consideration of variables typically not measured by job satisfaction instruments. Subjects are 185 employees working within two research and development units of two multinational corporations. The short-form Minnesota Satisfaction Questionnaire was used to obtain the sum of the facet satisfactions. Two single-item global questions of overall satisfaction were also used. One required a yes-no response and the second, a 1–5 rating response. Information about perceived determinants of job satisfaction, overall satisfaction with the job, satisfaction with occupational choice, career progress, and overall satisfaction with non-job related events was obtained through semi-structured interviews. Results indicate that defining overall job satisfaction as the sum of the evaluations of the discrete elements of which the job is composed, may lead to neglect of major determinants of job satisfaction. The “whole” appears to be more complex than the sum of the presently measured parts. Results also suggest that the 1–5 global rating of overall job satisfaction may be a more inclusive measure of overall job satisfaction than summation of many facet responses.

Evaluation of the water potentials of solutions of polyethylene glycol 8000 both in the absence and presence of other solutes.

Abstract: Published and additional data for polyethylene glycol 8000 (PEG), formerly PEG 6000, solution water potentials (Ψ) are compared. Actual bars Ψ over the concentration range of 0 to 0.8 gram PEG per gram H2O and temperature (T) range of 5 to 40°C are best predicted (probably within ± 5%) by this equation: Ψ = 1.29[PEG]2T − 140[PEG]2 − 4.0[PEG]. Although transformable through division by [PEG] to virial equation form, results indicate that the coefficients are not virial. Mannitol (MAN) interacts with PEG to produce Ψ significantly lower than additive. Vapor pressure osmometer (VPO) data for MAN-PEG synergism compared favorably with those from thermocouple hygrometry; and VPO data showing the interactions between PEG and four salts are presented. The synergism of MAN-PEG and of NaCl-PEG are related linearly to the concentration of solute added with PEG.

The Constructivist Researcher as Teacher and Model Builder

Abstract: The constructivist teaching experiment is used in formulating explanations of children’s mathematical behavior. Essentially, a teaching experiment consists of a series of teaching episodes and individual interviews that covers an extended period of time—anywhere from 6 weeks to 2 years. The explanations we formulate consist of models—constellations of theoretical constructs—that represent our understanding of children’s mathematical realities. However, the models must be distinguished from what might go on in children’s heads. They are formulated in the context of intensive interactions with children. Our emphasis on the researcher as teacher stems from our view that children’s construction of mathematical knowledge is greatly influenced by the experience they gain through interaction with their teacher. Although some of the researchers might not teach, all must act as model builders to ensure that the models reflect the teacher’s understanding of the children.

On a problem of Oppenheim concerning “factorisatio numerorum”

Abstract: Saccharomyces uvarum, Geotrichum candidum, Endomycopsis burtonii and Hansemula canadensis have been isolated from deteriorated silages and/or spoiled lactic acid fermented foods. All yeasts could grow in relatively high (100 mmol/l) concentrations of acetate or lactate in Wickerham's assimilation broth but were inhibited by increasing concentrations of these acids. Propionate was much more inhibitory than acetate or lactate. Growth rate, but not final cell yield, was adversely affected by increasing concentrations of these acids. The three acids used in combination were synergistically inhibitory to H. canadensis and G. candidum. Saccharomyces uvarum was inhibited by synergistic mixtures of acetate/propionate. Endomycopsis burtonii and H. canadensis were inhibited by synergistic mixtures of acetate/lactate, acetate/propionate and lactate/propionate. Lactate and propionate had a synergistic inhibitory effect on G. candidum. The mechanism of inhibition of growth of S. uvarum by acetate and propionate was further investigated. Acetate and propionate each caused a reduction in cellular efficiency (Y, μg cells/μmole glucose consumed). Mixtures caused a drastic reduction in growth rate and Y. These results suggest that the cells may expend energy in reducing intracellular concentrations of acetate while propionate probably acts in a different manner.

Inhibition of the growth of acid tolerant yeasts by acetate, lactate and propionate and their synergistic mixtures

Abstract: Saccharomyces uvarum, Geotrichum candidum, Endomycopsis burtonii and Hansemula canadensis have been isolated from deteriorated silages and/or spoiled lactic acid fermented foods. All yeasts could grow in relatively high (100 mmol/l) concentrations of acetate or lactate in Wickerham's assimilation broth but were inhibited by increasing concentrations of these acids. Propionate was much more inhibitory than acetate or lactate. Growth rate, but not final cell yield, was adversely affected by increasing concentrations of these acids. The three acids used in combination were synergistically inhibitory to H. canadensis and G. candidum. Saccharomyces uvarum was inhibited by synergistic mixtures of acetate/propionate. Endomycopsis burtonii and H. canadensis were inhibited by synergistic mixtures of acetate/lactate, acetate/propionate and lactate/propionate. Lactate and propionate had a synergistic inhibitory effect on G. candidum. The mechanism of inhibition of growth of S. uvarum by acetate and propionate was further investigated. Acetate and propionate each caused a reduction in cellular efficiency (Y, μg cells/μmole glucose consumed). Mixtures caused a drastic reduction in growth rate and Y. These results suggest that the cells may expend energy in reducing intracellular concentrations of acetate while propionate probably acts in a different manner.

A world model of soil carbon dioxide

Abstract: Mean growing season soil PCO2 data were obtained for 19 regions of the world in nine countries. Bivariate and multiple linear regression analysis with soil log(PCO2) as the dependent variable and TEMP, PRECIP, log(AET), and log(PET) as the four climatic independent variables demonstrated that AET was the best independent predictor of soil PCO2. An improved soil PCO2-AET model was developed by assuming (1) that as AET approaches zero, soil PCO2 approaches the atmospheric value and (2) that there is an upper limit to soil PCO2 at very high AET. This model has the form log(PCO2) = −3·47 + 2·09 (1 −e−0·0172 AET) where AET is in mm. It explains 67 per cent of the initial variation in the soil PCO2 data, predicts a soil log(PCO2) of − 3·47 at AET = 0, and an upper limit of 3·5 per cent (log(PCO2) = − 1·45) for mean growing season soil PCO2 at AET values of 2000 mm and above. The results of this study suggest that soil PCO2 levels in tropical areas are, on average, higher than those in temperate, alpine, and arctic regions.

The role of calcium and phosphorus in the etiology of tibial dyschondroplasia in young chicks.

Abstract: By means of a central composite rotatable design with dietary calcium levels of 0.63, 0.70, 1.10, 1.50 and 1.67% and total phosphorus levels of 0.53, 0.61, 0.81, 1.01 and 1.09%, practical-type rations were fed for 2 weeks to commercial broiler-type chickens. The design involved three replicates for each rotatable point and 15 replicates for the central point with 10 cockerels per replicate or a total of 390 birds. When the experiment was terminated, the chickens were weighted and killed; one tibia was used to determine bone ash and the other tibia for scoring the incidence and severity of tibial dyschondroplasia. The incidence of tibial dyschondroplasia in chickens fed the various diets ranged from 0 to 37%. A high incidence of tibial dyschondroplasia was associated with diets containing high phosphorus and low calcium levels. Tibial dyschondroplasia score and percentage of bone ash were not correlated. No obvious relationships existed between tibial dyschondroplasia incidence and percentage retention of calcium and phosphorus. A second experiment confirmed the finding that increased dietary calcium levels would reduce the incidence of tibial dyschondroplasia when chickens were fed diets high in phosphorus.

Mitochondrial DNA differentiation during the speciation process in Peromyscus.

Abstract: We address the problem of the possible significance of biological speciation to the magnitude and pattern of divergence of asexually transmitted characters in bisexual species. The empirical data for this report consist of restriction endonuclease site variability in maternally transmitted mitochondrial DNA (mtDNA) isolated from 82 samples of Peromyscus polionotus and P. leucopus collected from major portions of the respective species' ranges. Data are analyzed together with previously published information on P. maniculatus, a sibling species to polionotus. Maps of restriction sites indicate that all of the variation observed can be reasonably attributed to base substitutions leading to loss or gain of particular recognition sites. Magnitude of mtDNA sequence divergence within polionotus (maximum approximately equal to 2%) is roughly comparable to that observed within any of five previously identified mtDNA assemblages in maniculatus. Sequence divergence within leucopus (maximum approximately equal to 4%) is somewhat greater than that within polionotus. Consideration of probable evolutionary links among mtDNA restriction site maps allowed estimation of matriarchal phylogenies within polionotus and leucopus. Clustering algorithms and qualitative Wagner procedures were used to generate phenograms and parsimony networks, respectively, for the between-species comparisons. Three simple graphical models are presented to illustrate some conceivable relationships of mtDNA differentiation to speciation. In theoretical case I, each of two reproductively defined species (A and B) is monophyletic in matriarchal genealogy; the common female ancestor of either species can either predate or postdate the speciation. In case II, neither species is monophyletic in matriarchal genotype. In case III, species B is monophyletic but forms a subclade within A which is thus paraphyletic with respect to B. The empirical results for mtDNA in maniculatus and polionotus appear to conform closely to case III. These theoretical and empirical considerations raise a number of questions about the general relationship of the speciation process to the evolution of uniparentally transmitted traits. Some of these considerations are presented, and it is suggested that the distribution patterns of mtDNA sequence variation within and among extant species should be of considerable relevance to the particular demographies of speciation.

The Effects of Watershed Disturbance on Dissolved Organic Carbon Dynamics of a Stream

Abstract: The response of a stream ecosystem to disturbance in its watershed was investigated by comparing mass balances of dissolved organic carbon (DOC) for a stream draining an undisturbed watershed with a stream draining a watershed that was clear-cut 2 yr before the study began. These second-order streams are in the Coweeta Hydrologic Laboratory, North Carolina. Both streams had similar, elevated DOC concentrations (from <1 to 5 mg/L) during storms. Rising and falling limbs of the hydrograph also had similar DOC concentrations. During the growing season DOC concentration increased from headwater seep to the weir in the undisturbed stream under baseflow conditions. No significant longitudinal change was observed in the stream draining the clear-cut watershed. Hence concentration was consistently lower in baseflow samples during the growing season in the stream draining the clear-cut watershed. As a result annual DOC export from the clear-cut watershed was less (9.8-11.5 kg/ha) than from the reference watershed (14.6-15.1 kg/ha). The lower DOC export was partly due to reduced DOC inputs from throughfall and leaching of fresh litter, but most impor- tantly to lower DOC inputs in subsurface water and probably also less in-stream generation of DOC. The rate of recovery of this stream from disturbance is therefore dependent on the rate at which the terrestrial system recovers.

Fish Schools: An Asset to Corals

Abstract: Schools of juvenile haemulid fish feed in sea grass beds at night. By day they rest over coral heads, where they excrete substantial quantities of ammonium and particulate nitrogen and phosphorus into the nutrient-poor waters. The percentages of these nutrients contributed by the fish were comparable to those from other sources. Coral heads with resident fish schools grew faster than those without resident schools, indicating that fish may be more beneficial to the corals than has been assumed.

Rapid Degradation of Unassembled Ribulose 1,5-bisphosphate Carboxylase Small Subunits in Chloroplasts

Abstract: We have detected a proteolytic mechanism in chloroplasts that selectively and rapidly degrades the imported small subunit of ribulose 1,5-bisphosphate carboxylase when pools of the chloroplast-synthesized large subunit are depleted. This degradation system is constitutively present and appears to be responsible for precise stoichiometric accumulation of the two subunits of the enzyme. We believe similar proteolytic mechanisms participate in regulating the accumulation of other photosynthetic proteins during chloroplast biogenesis.

Phases of Progressive Burnout and Their Work Site Covariants: Critical Issues in OD Research and Praxis:

Abstract: The term "burnout" represents a significant perspective on how people respond to their work, but the attention paid to this phenomenon has largely been clinical and often anecdotal In this article, the authors seek to expand the analysis of burnout in ways that permit comparative analysis, especially in large populations This study specifically addresses three questions First, does a paper-and-pencil instrument isolate domains of burnout that are relatively consistent between people-intensive work and the broader range of activities found in a commercial enterprise? Second, can we develop phases of progressive burnout? Third, can we test the efficacy of the burnout phases by searching for regularities in a panel of 22 variables commonly thought to tap the important facets of the work site? The author's analysis shows that we can answer these three central questions affirmatively, though occasionally with complex and potentially significant qualifications The results of the analysis provide further evidence of the usefulness of a convenient instrument for measuring burnout and also suggest that behavioral scientists will find valuable a phase model that distinguishes regular and robust covariation by using a panel of variables thought to tap the important aspects of organizational life

Stability of Stream Ecosystems

Abstract: The ability of ecosystems to recover from external disturbances, that is, their stability, is a fundamental property of these systems. Quantification of the ability for various ecosystems to recover and understanding of the mechanisms behind stability are currently areas of major ecological research. In this paper we present an overview of how the stability concept has been used in ecology and a more specific discussion of the application of these ideas to stream ecosystems. This is followed by a case study in which we have been observing the stability of small streams in response to watershed logging and comparing stream stability to stability of the adjacent forest ecosystem.

A meta-analysis of the effects of various science teaching strategies on achievement

Abstract: This study is a meta-analysis of the question “What are the effects on achievement of different teaching techniques?” Twelve categories of teaching techniques were specified. Among these are questioning, wait-time, testing, focusing, manipulative, presentation approach, inquiry or discovery, audio-visual, and teacher direction. A coding form was then developed to allow for the uniform examination and recording of 76 variables from each study. One or more effect sizes were calculated and coded for each study. Over 300 microfilmed dissertations covering the past 30 years were examined. Some 2000 ERIC science abstracts were reviewed and suitable studies obtained. Finally, journal articles were reviewed. A total of 400 effect sizes representing 160 studies were produced. The main effect size overall was 0.34. Thus, for all samples considered the experimental science teaching techniques on the average resulted in one-third of a standard deviation improvement over traditional techniques. Mean effect sizes also were calculated for each technique. More than 20 other variables such as class size, community type, and science subject area were cross-tabulated with effect size.

Developmental cell interactions in Myxococcus xanthus and the spoC locus.

Abstract: The product(s) of the Myxococcus xanthus spoC locus is required for two multicellular activities in fruiting body development, rippling and sporulation. Ripples, which are formed early in development, are spatially separated ridges of cells that move synchronously. Myxospores are heat-resistant resting cells that are formed near the end of the developmental process. To investigate the function of spoC, it was cloned in an Escherichia coli plasmid, then transferred to M. xanthus by specialized transduction with coliphage P1. The plasmid, which cannot replicate in M. xanthus, integrated into the M. xanthus chromosome, producing two copies of the spoC locus in tandem. Cells containing one copy of a mutant allele and one copy of the wild-type allele displayed the wild-type phenotype. Cells containing two different mutant alleles failed to ripple or sporulate, implying that all four independent spoC mutations are in the same gene or unit of transcription. Homozygous mutant duplications arose from constructions in which DNA from a spo+ donor was transduced into a spoC recipient, or vice versa, at an average frequency of 14%, indicating that gene conversion was a frequent event.

Effects of Sounds on Preferences for Outdoor Settings

Abstract: Three methods were used to assess the influence of a number of realistic sound stimuli on esthetic evaluations of outdoor settings. We reproduced 18 sounds-including those of children, songbirds, construction equipment, automobiles, aircraft, and wind-for college students serving as evaluators at field sites ranging from a forest to a downtown street. In two other procedures, settings and sounds were described in a questionnaire, or were presented using photographs and tape recordings. All.three procedures produced similar results; natural and animal sounds had enhancing effects on evaluations of the heavily wooded natural and residential sites, and other sounds had detracting effects on the same sites. The sounds were relatively neutral in effect at two downtown streets, where traffic sounds were found to be most enhancing. The results show that the interaction of a setting's visual and acoustic characteristics significantly influences evaluations of that setting, and that appropriateness of sounds only ...

The influence of elevated nitrate concentration on rate of leaf decomposition in a stream

Abstract: SUMMARY. 1 Leaf decomposition was compared in two streams at the Coweeta Hydrologic Laboratory, North Carolina. U.S.A. One stream drains an undisturbed hardwood watershed, while the other drains a successional watershed subject to an insect outbreak. The successional watershed has elevated nitrate concentrations in the streamwater. 2 Both black locust (Robinia pseudo-acacia) and sweet birch (Betula lenta) leaf litter decomposed 2.8 times more rapidly in the stream with high nitrate concentrations. 3 The more rapid decay rates appeared to be partly due to accelerated microbial processing in response to nitrate enrichment, because microbial biomass (as ATP) was higher in the nitrate-enriched stream. 4 At each point in time, nitrogen and phosphorus content of the litter was lower in the high nitrate stream; however, there was no significant difference in nitrogen or phosphorus content at the same state of leaf decay in the two streams.

Extensive genetic variation in mitochondrial dna's among geographic populations of the deer mouse, peromyscus maniculatus.

Abstract: Restriction endonucleases have recently permitted the detection of extensive intraspecific mitochondrial DNA (mtDNA) sequence heterogeneity in a number of mammalian species (e.g., Potter et al., 1975; Upholt and Dawid, 1977; Avise et al., 1979b; Brown, 1980; Brown and Simpson, 1981; Ferris et al., 1981). Because mtDNA appears to evolve very rapidly (Brown et al., 1979), and because mtDNA seems to be strictly maternally inherited (Hutchison et al., 1974; Lansman et al., 1983), the molecule has been advocated as a potentially useful marker for estimating matriarchal phylogenies within and among conspecific populations and closely related species (Lansman et al., 1981). To date, however, only a small handful of studies have begun to exploit this potential for natural population analysis (Avise et al., 1979b; Brown and Wright, 1979; Brown, 1980; Brown and Simpson, 1981; Ferris et al., 1981a, 1981b). In the first paper of this series, we included a description of mtDNA restriction fragment divergence among three geographically distant samples of the deer mouse, Peromyscus maniculatus (Avise et al., 1979a). Of particular interest was the observation that samples from Colorado and southern Michigan were very similar in mtDNA sequence (estimated nucleotide divergence, P .005), while a sample from North Carolina was very distinct from these (P .040). Here we greatly extend our survey of the deer mouse by analyzing mtDNA sequence variation in 135 animals collected across much of the vast range of the species in North America. Our procedure has been to map restriction sites recognized by eight endonucleases. The restriction maps permit comparisons of the pattern and character of changes in the mtDNA molecule that have occurred during its evolutionary history in P. maniculatus. Thus the data presented in this paper are of considerable significance to two different but closely interrelated aspects of mtDNA evolution: (1) the ' Number IV in the series, "The use of restriction endonucleases to measure mitochondrial DNA sequence relatedness in natural populations." 2 Current address: Laboratory of Genetics, National Institute of Environmental Health Sciences, Research Triangle Park; North Carolina 27709.

Morphology, flow regimes, and filtering rates of Daphnia, Ceriodaphnia, and Bosmina fed natural bacteria.

Abstract: Body size is the best overall indicator of the abilities of the cladocerans Daphnia magna, D. parvula, Ceriodaphnia lacustris and Bosmina longirostris to filter natural bacteria (<1.0 μm). However, species differences exist which cannot be inferred from differences in size, behavior, or morphology alone. The relationship between filtering rate (FR in ml animal-1h-1) and body length (L in mm) for the cladocerans studied can be described by the power function: [Formula: see text] In D. parvula, algal filtering rates are higher and increase more rapidly with increasing body size than do bacterial filtering rates which are 26 to 33% of algal rates. This suggests that different processes may be involved in the capture of these ultrafine particles and that ultrafine particle capture efficiency decreases with increasing body size within a species. Weight specific filtering rates (in μl μg dry wt-1h-1) have a strong negative relationship to body size and show species specific differences. Appendage beat rates intersetular distances, setule diameter, appendage, area, % open space on the filtering appendage, Reynolds number, and boundary layer thickness do not provide simple predictions of bacterial filtering rates for the cladocerans studied. Filtering rates on cultured laboratory bacteria and algae may not indicate filtering rates on natural bacterioplankton because of differences in bacterial size, motility, and surface properties. Uptake of ultrafine particles may be enhanced by the presence of larger, more readily filtered particles through a "piggybacking" phenomenon.

Motivational interpretations of hindsight bias: An individual difference analysis

Abstract: When individuals learn the outcome of an event or the correct answer to a question, they overestimate its prior predictability: that is, they tend to believe they “knew it all along.” Cognitive and motivational interpretations of hindsight bias are briefly reviewed and a study designed to test the motivational interpretation is reported. Specifically, it was hypothesized that individual differences in the strengths of two motives, a need for predictability and a self-presentation motive, should be positively related to individual differences in the magnitude of hindsight bias. Sixty-eight subjects completed a Dogmatism Scale and an Intolerance for Ambiguity Scale (the predictability motive) and the Marlowe-Crowne Social Desirability Scale (the self-presentation motive) before participating in a standard hindsight-bias paradigm. Measures of both motives, as well as a self-reported ego-involvement measure, were positively associated with the amount of hindsight bias exhibited. Implications of this result for interpretations of hindsight and other conceptually related phenomena are discussed.

Diel vertical migration by zooplankton: Constant and fluctuating temperature effects on life history parameters of Daphnia1

Abstract: Abstruct The thermal demographic advantage of vertical migration was tested using life-table studies of Daphnia parvula cohorts fed on Chlamydomonas reinhurdi. At a high food level, lifespan and body size at death were relatively insensitive to temperature differences. Fecundity parameters (brood size, brood number, total number of young per reproductive female, and net reproduction rate) were highest at an optimal midrange temperature (15°C). However, age at onset of reproduction, instar at first reproduction and brood duration decreased with increasing temperature, resulting in an overall increase in the realized rate of increase (r) with increasing temperature. Realized rates of increase were higher in fluctuating temperatures than at comparable average constant temperatures but were always lower than those at the highest constant temperature in each range. A low food level reduced the effect of temperature on some growth and fitness parameters from those at a high food level, but T was still greater at the higher temperatures. Therefore, there is no apparent thermal demographic advantage to vertical migration at either a high or low food level within the natural range experienced by D. purvulu. Maximum fitness is achieved by remaining in the warmest surface waters at all times.

Phosphofructokinase activities in photosynthetic organisms : the occurrence of pyrophosphate-dependent 6-phosphofructokinase in plants and algae.

Abstract: A pyrophosphate-dependent phosphofructokinase (PPi-PFK) activity is detectable in extracts of a wide variety of primitive and advanced plants, the Charalean algae, and in the photosynthetic bacterium, Rhodospirillum rubrum. Angiosperms with extractable PPi-PFK activities 4- to 70-fold higher than the respective ATP-PFK activities tend to be succulent and to exhibit CAM. Even though PPi-PFK activity is not detected in crude extracts of some well known CAM plants, e.g. plants in the Crassulaceae, gel filtration of the extract and/or inclusion of the PPi-PFK activator, fructose 2,6-bisphosphate, in the assay reveals that a PPi-PFK activity is present in these species. Fructose 2,6-bisphosphate likewise activates PPi-PFK activities in extracts of C3 and C4 plants. C3 and C4 plant PPi-PFK activities are roughly equivalent to ATP-PFK activities in the same species. PPi-PFK activity is also detected in some bryophytes, lower vascular plants, ferns, and gymnosperms. The Charophytes, advanced algae presumed to be similar to species ancestral to vascular plants, exhibit at least 4-fold higher PPi-PFK than ATP-PFK activities. R. rubrum also exhibits a much higher PPi-PFK activity than ATP-PFK activity. These data indicate that PPi-PFK may serve as an alternate enzyme to ATP-PFK in glycolysis in a wide range of photosynthetic organisms.

Critical and multicritical behavior in a triangular-lattice-gas Ising model: Repulsive nearest-neighbor and attractive next-nearest-neighbor coupling

Abstract: Monte Carlo simulations have been used to study a triangular lattice-gas (Ising) model with repulsive nearest-neighbor interactions and attractive next-nearest-neighbor coupling. We find two ordered ($\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3}$) phases (one with $\frac{1}{3}$ of the sites occupied and one with $\frac{2}{3}$ of the sites filled). These ordered phases are separated from the disordered state by a phase boundary which is second order at high temperatures and which has tricritical points and first-order transitions at low temperatures. The critical and tricritical exponents are consistent with those predicted for the three-state Potts model. At 50% coverage we find a low-temperature ordered phase which is separated from the disordered state by an $\mathrm{XY}$-like line of critical points which exist between upper and lower temperatures ${T}_{1}$ and ${T}_{2}$, respectively. Along this line between ${T}_{1}$ and ${T}_{2}$ we find nonuniversal critical behavior and identify topological (vortexlike) excitations.