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Showing papers by "Stockholm University published in 1990"


Book ChapterDOI
01 Jan 1990
TL;DR: In the H&H program the quest for phonetic invariance is replaced by another research task: Explicating the notion of sufficient discriminability and defining the class of speech signals that meet that criterion.
Abstract: The H&H theory is developed from evidence showing that speaking and listening are shaped by biologically general processes. Speech production is adaptive. Speakers can, and typically do, tune their performance according to communicative and situational demands, controlling the interplay between production-oriented factors on the one hand, and output-oriented constraints on the other. For the ideal speaker, H&H claims that such adaptations reflect his tacit awareness of the listener’s access to sources of information independent of the signal and his judgement of the short-term demands for explicit signal information. Hence speakers are expected to vary their output along a continuum of hyper- and hypospeech. The theory suggests that the lack of invariance that speech signals commonly exhibit (Perkell and Klatt 1986) is a direct consequence of this adaptive organization (cf MacNeilage 1970). Accordingly, in the H&H program the quest for phonetic invariance is replaced by another research task: Explicating the notion of sufficient discriminability and defining the class of speech signals that meet that criterion.

1,574 citations


Journal ArticleDOI
Gunnar Borg1
TL;DR: In this paper some of the basic concepts and methods of psychophysics have been described and a new category ratio scale, commonly referred to as the CR-10 scale, is presented together with new category rating scales.
Abstract: In studies on work it is important to assess various subjective symptoms, complaints, and annoyances. To measure such symptoms, psychophysical ratio scales may be used, as along with simpler category rating scales. In this paper some of the basic concepts and methods of psychophysics have been described. In the field of heavy physical work and the perception of effort and exertion, one of the most popular methods is the rating of perceived exertion. This scale has been presented together with a new category ratio scale, commonly referred to as the CR-10 scale. Some situations in which it is important to obtain measurements of perceived exertion have also been described in the paper.

1,555 citations


Journal ArticleDOI
TL;DR: This phenomenon, which involves employees “ganging up” on a target employee and subjecting him or her to psychological harassment, results in severe psychological and occupational consequences for the victim.
Abstract: In recent years, the existence of a significant problem in workplaces has been documented in Sweden and other countries. It involves employees "ganging up" on a target employee and subjecting him or her to psychological harassment. This "mobbing" behavior results in severe psychological and occupational consequences for the victim. This phenomenon is described, its stages and consequences analyzed. An ongoing program of research and intervention that is currently being supported by the Swedish government is then considered.

1,258 citations


Journal ArticleDOI
08 Jun 1990-Science
TL;DR: A rough analysis based on the use of currently accepted values shows that natural gas is preferable to other fossil fuels in consideration of the greenhouse effect as long as its leakage can be limited to 3 to 6 percent.
Abstract: The current concern about an anthropogenic impact on global climate has made it of interest to compare the potential effect of various human activities. A case in point is the comparison between the emission of greenhouse gases from the use of natural gas and that from other fossil fuels. This comparison requires an evaluation of the effect of methane emissions relative to that of carbon dioxide emissions. A rough analysis based on the use of currently accepted values shows that natural gas is preferable to other fossil fuels in consideration of the greenhouse effect as long as its leakage can be limited to 3 to 6 percent.

779 citations


Journal ArticleDOI
01 Aug 1990-Nature
TL;DR: This article used tree-ring data to reconstruct the mean summer (April-August) temperature of northern Fennoscandia for each year from AD 500 to the present, and showed that any summer warming induced by greenhouse gases may not be detectable in this region until after 2030.
Abstract: Tree-ring data have been used to reconstruct the mean summer (April-August) temperature of northern Fennoscandia for each year from AD 500 to the present. Summer temperatures have fluctuated markedly on annual, decadal and century timescales. There is little evidence for the existence of a Medieval Warm Epoch, and the Little Ice Age seems to be confined to the relatively short period between 1570 and 1650. This challenges the popular idea that these events were the major climate excursions of the first millennium, occurring synchronously throughout Europe in all seasons. An analysis of past warming trends suggests that any summer warming induced by greenhouse gases may not be detectable in this region until after 2030.

538 citations


Journal ArticleDOI
TL;DR: The hypothesis that erythrocyte rosetting contributes to the pathogenesis of cerebral malaria is supported and the suggestion that anti-rosetting antibodies protect against cerebral disease is suggested.

466 citations


Journal ArticleDOI
TL;DR: In this article, a broad trend in modern corporate life is portrayed and conceptualized as a development from a strong focusing on "substantive" issues to an increased emphasis on dealing with images as a critical aspect of organizational functioning and management.
Abstract: This paper discusses the increased theoretical and practical interest in the ideational dimensions of organizations, with particular emphasis on corporate images. The role of these internally in organizations, and not only for the regulation of external relations, in large parts of the modern economy is emphasized. The preconditions for the appearance of images as objects of systematic control and instrumental action in organizations are investigated. A broad trend in modern corporate life is portrayed and conceptualized as a development from a strong focusing on “Substantive” issues to an increased emphasis on dealing with images as a critical aspect of organizational functioning and management. This means, among other things, that pseudo-events, pseudo-actions and pseudo-structures, i.e. phenomena which has the purpose of producing effects on people’s impressions and definition of reality, are important features of modern management and organization.

377 citations


Journal ArticleDOI
TL;DR: A version of the sequential assessment game with several behavioural options has been developed, and here predictions from this model are tested using data from 102 staged fights between males of the cichlid fish Nannacara anomala.

368 citations


Journal ArticleDOI
TL;DR: In this paper, a sequential assessment game is developed in which a fight can end because a contestant either gives up or is killed, and it is shown that when the value of a contested resource is similar to or greater than the future, strategies will evolve that result in contestants being severely injured or killed during fights.

340 citations


Journal ArticleDOI
TL;DR: This study describes the population structure of Norway spruce (Picea abies) as revealed by protein polymorphisms and morphological variation.
Abstract: This study describes the population structure of Norway spruce (Picea abies) as revealed by protein polymorphisms and morphological variation. Electrophoretically detectable genetic variability was examined at 22 protein loci in 70 populations from the natural range of the species in Europe. Like other conifers, Norway spruce exhibits a relatively large amount of genetic vari- ability and little differentiation among populations. Sixteen polymorphic loci (73%) segregate for a total of 51 alleles, and average heterozygosity per population is 0.1 15. Approximately 5% of the total genetic diversity is explained by differences between populations (GsT = 0.052), and Nei's standard genetic distance is less than 0.04 in all cases. We suggest that the population structure largely reflects relatively recent historical events related to the last glaciation and that Norway spruce is still in a process of adaptation and differentiation. There is a clear geographic pattern in the variation of allele frequencies. A major part of the allele- frequency variation can be accounted for by a few synthetic variables (principal components), and 80% of the variation of the first principal component is "explained" by latitude and longitude. The central European populations are consistently depauperate of genetic variability, most likely as an effect of severe restrictions of population size during the last glaciation. The pattern of differentiation at protein loci is very similar to that observed for seven morphological traits ex- amined. This similarity suggests that the same evolutionary forces have acted upon both sets of characters.

336 citations


Journal ArticleDOI


Journal ArticleDOI
TL;DR: The bioaccumulation of 4-nonylphenol has been studied in shrimps, mussels and sticklebacks exposed to (14)C-NP in running seawater and the bioconcentration factor determined of NP in fish was 1300 and in mussels, 3400.

Journal ArticleDOI
TL;DR: The effect of phosphorylation on the functional activity of eukaryotic elongation factor 2 (eEF-2) was studied using a purified phosphorylated factor, and the modified factor was unable to stimulate protein synthesis in an e EF-2-dependent rabbit reticulocyte lysate.
Abstract: The effect of phosphorylation on the functional activity of eukaryotic elongation factor 2 (eEF-2) was studied using a purified phosphorylated factor. The modified factor was unable to stimulate protein synthesis in an eEF-2-dependent rabbit reticulocyte lysate. The functional alteration was further analyzed by measuring the effects of phosphorylation on the ability of the factor to catalyse the ribosome-dependent hydrolysis of GTP. Kinetic analysis showed that both phosphorylated and unmodified factor was able to hydrolyse GTP with approximately the same maximum rate, indicating that the rate of nucleotide exchange was not impaired by the modification. However, the phosphorylated factor showed a marked reduction in the second-order rate constant, suggesting that the phosphorylation interfered with ribosome · eEF-2 complex formation by reducing the affinity of eEF-2 for the ribosome. This assumption was confirmed by direct measurements of the dissociation constants for the ribosomal complexes containing unmodified and phosphorylated eEF-2.

Journal ArticleDOI
TL;DR: In this paper, isolated genomic clones that cover the cecropin locus in Drosophila melanogaster were found, and it was mapped cytologically to the chromosomal location 99E.
Abstract: Cecropins are antibacterial peptides that are synthesized in insects as a response to infection. As a first step towards a molecular study of the induction of this response, we have isolated genomic clones that cover the cecropin locus in Drosophila melanogaster. This locus was found to be unique, and it was mapped cytologically to the chromosomal location 99E. Sequence analysis showed it to be unusually compact, with three expressed genes and two pseudogenes within less than 4 kb of DNA, and with another homologous region less than 4 kb away. Two of the genes, A1 and A2, encode a product that is identical to the major cecropin from Sarcophaga peregrina, while the cecropin encoded by the B gene differs in five positions. Cecropin transcripts appear within an hour after bacteria have been injected into the hemocoel, reach a maximum after 2-6 h, and have almost disappeared again after 24 h. The B gene is induced in parallel with the A genes, but on a lower level. The cecropin genes were also induced when the flies were kept on food with the Drosophila pathogenic bacterium Serratia marcescens Db10 or its non-pathogenic derivative Db1140.

Journal ArticleDOI
21 Dec 1990-Science
TL;DR: Functional analyses indicate that hemolin is one of the first hemolymph components to bind to the bacterial surface, taking part in a protein complex formation that is likely to initiate the immune response.
Abstract: Insects have an efficient defense system against infections. Their antibacterial immune proteins have been well characterized. However, the molecular mechanisms by which insects recognize foreignness are not yet known. Data are presented showing that hemolin (previously named P4), a bacteria-inducible hemolymph protein of the giant silk moth Hyalophora cecropia, belongs to the immunoglobulin superfamily. Functional analyses indicate that hemolin is one of the first hemolymph components to bind to the bacterial surface, taking part in a protein complex formation that is likely to initiate the immune response.

Journal ArticleDOI
T. Sjøvold1
TL;DR: The weighted line of organic correlation (WOC) as discussed by the authors was proposed to estimate the proportion of a skeleton to a given set of individuals in a given population, and has been shown to be suitable for use not only for forensic purposes, but also for the estimation of stature based on skeletons or skeletal populations.
Abstract: Estimation of stature from skeletal measurements is of great interest in some studies, e.g. in forensic anthropology, where victims have to be identified. A problem occurring in practice is that the individual whose stature has to be assessed is in general from an unknown population. Alternatives to ordinary least squares regression are discussed. Application of available information about stature/long bone proportions leads to a general proposal called thethe weighted line of organic correlation, which is fitted to a wide range of populations. The effects of sex and race upon this line are practically negligible. These properties makes it suitable for use not only for forensic purposes, but also for the estimation of stature based on skeletons or skeletal populations from the past.

Journal ArticleDOI
TL;DR: The evidence available on gender differences in nutrition and health in Sub-Saharan Africa is scant as mentioned in this paper, and the most comprehensive quantitative information has been published by Schofield (1979, p. 87), who reported that adult males fulfilled 101 per cent of their estimated calorie requirement, while women only filled 96 per cent, but the difference was not statistically significant.
Abstract: In recent years, several empirical investigations have suggested that female children in South Asia are more frequently undernourished than male children (Chen et al., 1980; 1981; Sen and Sengupta, 1983; das Gupta, 1987; Behrman, 1988), although there are a few counter-indications (Harriss, 1987). Schofield (1979, pp. 82–3) stated that ‘analysis of data from 94 Latin American villages showed that females aged 0–4 years fulfilled 87 per cent of their expected weight/age measurements compared with the 90 per cent level achieved by boys of the same age. The differences, as measured by the t-paired test, were found to be significant at the 0.5 per cent level.’ The evidence available on gender differences in nutrition and health in Sub-Saharan Africa is scant. The most comprehensive quantitative information has been published by Schofield (1979, p. 87). Her analysis of data from 11 African villages showed that adult males fulfilled 101 per cent of their estimated calorie requirement, while women only filled 96 per cent, but the difference was not statistically significant.

Journal ArticleDOI
TL;DR: A useful in vitro system to study the immune response has been found in Schneider's line 2 cells which respond to lipopolysaccharide and laminarin by cecropin expression.
Abstract: Cecropins are antibacterial peptides, induced in Drosophila as part of the humoral immune response to a bacterial invasion We have used the cloned Drosophila cecropin genes CecA1, A2 and B as probes to study the developmental and tissue specific regulation of this response The genes are strongly expressed in fat body and hemocytes after injection of bacteria, the CecA genes being much more active than CecB in the fat body All parts of the fat body and 5-10% of the hemocytes are involved in this response CecA1 and A2 are most active in larvae and adults; CecB is preferentially active in early pupae A small peak of constitutive cecropin expression in early pupae appears to be caused by bacteria in the food Cecropin A, the common product of the CecA1 and A2 genes, was identified in the hemolymph of immunized flies at a concentration of 25-50 microM, enough to kill all tested bacteria except Serratia, a Drosophila pathogen A useful in vitro system to study the immune response has been found in Schneider's line 2 cells which respond to lipopolysaccharide and laminarin by cecropin expression

Journal ArticleDOI
TL;DR: It was concluded that it is possible to promote precursor cells isolated as undifferentiated precursors from the interscapular brown adipose tissue of young mice to advance to such a state of differentiation that they can demonstrate the selective feature of the brown fat cell, i.e. the ability to express UCP.

Journal ArticleDOI
TL;DR: The infant's early touch of the mother's areola and nipple seemed to have positively influenced the mother/infant relationship during the first four days after birth, and was associated with lower maternal gastrin levels which suggests that maternal neuroendocrine functions were also influenced.

Journal ArticleDOI
TL;DR: The Mn cluster in the oxygen evolving complex has been localized by using known and estimated distances from the tyrosine radicals and it is suggested that a binding region for the Mn cluster is constituted by the lumenal ends of helices A and B and the loop connecting them in the D1 protein.
Abstract: Thirty-one and eleven sequences for the photosystem II reaction centre proteins D1 and D2 respectively, were compared to identify conserved single amino acid residues and regions in the sequences. Both proteins are highly conserved. One important difference is that the lumenal parts of the D1 protein are more conserved than the corresponding parts in the D2 protein. The three-dimensional structures around the electron donors tyrosineZ and tyrosineD on the oxidizing side of photosystem II have been predicted by computer modelling using the photosynthetic reaction centre from purple bacteria as a framework. In the model the tyrosines occupy two cavities close to the lumenal surface of the membrane. They are symmetrically arranged around the primary donor P680 and the distances between the centre of the tyrosines and the closest Mg ion in P680 are around 14 A. Both tyrosineZ and tyrosineD are suggested to form a hydrogen bond with histidine 190 from the loop connecting helices C and D in the D1 and D2 proteins, respectively. The Mn cluster in the oxygen evolving complex has been localized by using known and estimated distances from the tyrosine radicals. It is suggested that a binding region for the Mn cluster is constituted by the lumenal ends of helices A and B and the loop connecting them in the D1 protein. This part of the D1 protein contains a large number of strictly conserved carboxylic acid residues and histidines which could participate in the Mn binding. There is little probability that the Mn cluster binds on the lumenal surface of the D2 protein.

Journal ArticleDOI
TL;DR: Chloroplast transit peptides from the green alga Chlamydomonas reinhardtii have been analyzed and compared with chloroplast Transit peptide from higher plants and mitochondrial targeting peptidesFrom yeast, Neurospora and higher eukaryotes.

Journal ArticleDOI
TL;DR: The results reveal that the Photosystem II electron transport per se is less sensitive to high light at low temperatures in contrast to the overall photosynthetic process, and D1-protein degradation is severely retarded below 7°C.


Book ChapterDOI
TL;DR: Bacterial polysaccharides may also become acidic by the substitution of sugar residues, for example, by etherification with lactic acid, acetalation with pyruvic acid, or phosphorylation; these possibilities are also discussed in the chapter.
Abstract: Publisher Summary This chapter explains all the known components of bacterial polysaccharides, except the amino acids in peptidoglycans that had been reported in the literature before 1989. Five pentoses—namely, D -ribose, D - and L -arabinose, and D - and L -xylose, have been found in the hydrolyzates of bacterial polysaccharides. Six of the 18 aldohexoses,—namely, D -glucose, D - and L -mannose, D -galactose, D -allose, and L -altrose have been found in bacterial polysaccharides. Three heptoses—namely, L - glycero - D - manno -heptose, D - glycero - D - manno -heptose, and D - glycero - D - galacto -heptose have been found in bacterial polysaccharides. The aminodeoxyaldoses, when present in bacterial polysaccharides, are known as “pyranosides.” Bacterial polysaccharides may also become acidic by the substitution of sugar residues, for example, by etherification with lactic acid, acetalation with pyruvic acid, or phosphorylation; these possibilities are also discussed in the chapter. The number of known sugar components of bacterial polysaccharides at the end of 1988 was approximately 85. . The figure refers to the parent sugars, independent of the eventual substitution by O-methyl, O-(1-carboxyethyl), or other groups.

Journal ArticleDOI
TL;DR: The relationship between the distribution of benthic foraminifera and sediment type and depositional environment in the Arabian Sea is discussed in this article, where geochemical properties were found to correspond well to the sediment type, and six different sediment/depositional environment types could be distinguished.

Journal ArticleDOI
TL;DR: The possible existence of radiation sensitive and resistant patient groups is consistent with known genetic deficiencies such as ataxia telangiectasia for the sensitive patients and the existence of repair efficient head and neck tumors that are unusually efficient in repairing double strand breaks.
Abstract: Almost 200 patients have been treated for head and neck tumors at two different dose levels. Based on the clinically observed probabilities for tumor control and fatal normal tissue complications at the two dose levels, the dose giving maximum uncomplicated control has retrospectively been calculated and compared with the clinical data. A Poisson statistical model for control and complications has been used including a correlation parameter, delta, to describe the fraction of patients where control and complications are statistically independent. The clinically observed probability of uncomplicated tumor control, P+, is consistent with only a small fraction of the patients treated being statistically independent (delta = 0.2 or 20%). Customarily, 100% of the patients are assumed to be statistically independent with regard to tumor control and normal tissue complications. More precisely, the clinical data are consistent, with almost 20% of the patients being significantly more sensitive to radiation since they gain local tumor control but simultaneously suffer fatal complications. An even larger fraction of the patients (almost 30%) seemed to be more resistant to radiation, showing neither serious treatment complications nor control of the local tumor growth. It is suggested that if these patient groups could be identified by a predictive assay for the radiation sensitivity of their normal tissues and preferably also for their tumors, the uncomplicated tumor control could be increased by about 20%. This figure is based on the actuarial survival of the patients and has been corrected for the inevitable uncertainty in dose delivery. It is also pointed out that about 20% of the patients can never be saved by a predictive assay because of the considerable statistical variance associated with the Poisson process and the eradication of the last clonogenic tumor cell. Finally, note that the possible existence of radiation sensitive and resistant patient groups is consistent with known genetic deficiencies such as ataxia telangiectasia for the sensitive patients and the existence of repair efficient head and neck tumors that are unusually efficient in repairing double strand breaks. If such sensitive and resistant patient groups do exist, it should be sufficient to perform a predictive assay on normal tissues alone avoiding the often impossible task of sampling the most radiation resistant tumor cell line.


Journal ArticleDOI
TL;DR: IL 2, IL 4 and IFN‐γ accumulated in the Golgi system, which resulted in a characteristic morphology of the staining, eliminating problems with evaluation of background signals.
Abstract: The production of interleukin 2 (IL 2), IL 4 and interferon-gamma (IFN-gamma) by in vitro activated unselected human blood mononuclear cells was studied at a single-cell level. Individual lymphokine-synthesizing cells were identified by intracellular immunofluorescent staining using cytokine-specific monoclonal or polyclonal antibodies. Cultures from adult blood donors revealed a biphasic kinetic production pattern for IL 2 and IFN-gamma with peaks occurring 4-6 and 24-30 h after initiation of the cultures. Approximately 20%-40% of the lymphocytes produced IL 2 and IFN-gamma. In contrast, only 1%-3% of the lymphocytes synthesized IL 4 with maximal frequency after 6 h of culture. CD4+ as well as CD8+ T cells contributed to the synthesis of all three lymphokines studied. CD4+CD45R- T cells were the major producers of IL 2 and IL 4, while CD8+CD45R- T cells were the most common phenotype of IFN-gamma-synthesizing cells. By performing two-color immunofluorescence studies we observed that among IL 4-producing cells every second one made simultaneously IL 2 and every fourth one made IFN-gamma. Mononuclear cells from umbilical cord blood could be stimulated to make IL 2 to the same extent as cells from adult blood donors. No IL 4 production and a strikingly reduced frequency of IFN-gamma producers were noted in cell cultures from neonates. IL 2, IL 4 and IFN-gamma accumulated in the Golgi system, which resulted in a characteristic morphology of the staining, eliminating problems with evaluation of background signals.