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| 2. |
- Hultmark, Dan, 1949-
(författare)
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Insect immunity : Inducible antibacterial proteins from Hyalophora cecropia
- 1982
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A powerful bactericidal activity can be induced in the hemolymph of many insects as a response to an injection of bacteria. The nature of the effector molecules of this immune response was investigated, using pupae of the Cecropia moth, Hyalophora cecropia. Three major types of antibacterial proteins were found: the cecropins, the P5 proteins, and lysozyme. They appear in the hemolymph as a result of de novo synthesis.Six different cecropins were purified and characterized. The full amino acid sequences of the three major cecropins A, B and D were determined, as well as partial sequences of the three minor cecropins C, E and F. The cecropins are all very small (Mr = 4,000) and basic (pI > 9.5) proteins, and they show extensive homology in their sequences. The three major cecropins are products of different genes. Their C-terminals are blocked by uncharged groups, which can be removed by mild acid hydrolysis. The minor cecropins are closely related to the major forms, and may be unblocked precursors or, in one case (cecropin F), a minor allelic form. The cecropins were shown to be lytic, and to be efficient against several Gram positive and Gram negative bacterial strains, but not against mammalian cells.The P5 proteins are bactericidal proteins, larger than the cecropins (Mr = 20,000 - 23,000). Six forms, differing in isoelectric point, were isolated. They form two closely related groups, the basic (P5 A-D) and the acidic forms (P5 E-F). Within each group, the different forms have almost identical amino acid compositions.The Cecropia lysozyme is similar to lysozymes isolated from other insects, as well as to that from hen egg white. It is lytic to a restricted number of Gram positive bacteria.The presence of cecropins and other antibacterial factors was demon-strated also in other lepidopterans, notably Galleria mellonella, and may explain earlier observations of antibacterial factors in the latter species.
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| 3. |
- Lundgren, Nils-Gustav, 1951-
(författare)
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Skog för export : skogsarbete, teknik och försörjning i Lule älvdal 1870-1970
- 1984
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The forestry industry played an important role in the industrialization of the Swedish economy in the late 19th century. The aim of this study is to deed with the determination of income and wages in the forestry regions where the sawmills and pulp industries found their raw material supplies.The formation of incomes and wages for lumberjacks and drivers is analysed in the Parish of Jokkmokk in the far north of Sweden for the period 1878 to 1938. The number of workers engaged in forestry is also estimated as is the total labour supply in the parish.Technological development and productivity in felling and transportation are analysed. This part of the study covers the period 1880 to the present, and includes log-driving activities on the Lule River from 1881 to 1977.Briefly, the findings of the study are that income, timber prices and wages in forestry in the parish fluctuated together with exports of forestry products, particularly pulp after the year 1910. Estimates also show that troughs were deeper and booms more marked in the study area than in the overall market for forestry products measured both in volume and in export value.Labour productivity in felling and transport showed a rising tendency in the last two decades of the 19th century, which reflects the replacement of the axe as the only instrument for felling by the two-man timber saw. Better horses, fodder and sledges also raised efficiency.However, during the first half of the 20th century, labour productivity was markedly stagnant. Improvements in equipment, such as better steel in the saws, even stronger horses and so on, could not compensate for circumstances such as longer transporting distances and more cutting in the forests with lower volume per tree.These latter tendencies reflect a growing shortage of raw materials which the Swedish forestry industries had to face from about the turn of the century. Not until about 1955, when tractors replaced horses and the power saw replaced the one-man timber saw, did productivity rise substantially. Over a period of fifteen to twenty years, forestry work became almost completely mechanized.The labour force in the Parish of Jokkmokk was over 2,000 men in the boom of the 1930s. Today, the labour force is a steady 250 or so. The technological change in the 1960s was, of course, an adjustment to the extremely high labour costs in the Swedish post-war economy.In industry, a continuous adjustment to the factor proportions in the economy had taken place. In forestry, adjustment took place over a very short period of time after decades of stagnation from the technological point of view. Institutional, social and technical obstacles had delayed adjustments earlier. A totally new organization within forestry work was required before new techniques could be introduced. These were not applicable to older organization forms based on part-time farmers, part-time foresters.
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| 4. |
- Olsson, Mats-Olov
(författare)
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Den offentliga sektorn i samhällsekonomin : En problemorienterande studie av ekonomin i Västerbotten
- 1984
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- This book was the outcome of a research project analyzing the impact of the public sector on the regional economy. The project was initiated in the spring of 1982 by the regional office of The Swedish Confederation of Professional Employees (TCO). The research was performed at the Department of Regional Economics of Umeå University. Professor Åke E. Andersson supervised the work. A reference group of twelve people was attached to the project. Members of the group represented regional trade unions, business, and the public sector.The report contains four parts. Part I gives an introductory background to the following analysis. Part II contains an investigation of public sector demand from the regional business sector. In Part III some important current issues in public economics are discussed. The final Part IV summarizes the results of the investigation and some conclusions are formulated. The main purpose of the report was to provide an overview of certain important problematic issues in public economics. The primary focus was on a specific aspect of the real activity of the public sector — public sector production.
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| 6. |
- Agnemo, Roland, 1944-
(författare)
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Ligniners reaktioner med alkalisk väteperoxid
- 1981
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Under alkaline conditions hydrogen peroxide can be used either as a 1ignin-degrading or a 1ignin-preserving bleaching agent. If heavy metal ions are present and/or silicate is absent in the reaction medium, hydrogen peroxide decomposes via hydroxyl radicals and superoxide ions to oxygen and water. These decomposition products are able to react for example with phenolic lignin structures and thereby cause a partial degradation of lignin. In such a system peroxide could act as a bleaching and delignifying agent at the same time and these properties can be utilized for the bleaching of chemical pulps.In order to elucidate the factors which influence the degradation of phenolic structures by oxidation with alkaline hydrogen peroxide the lignin model compounds-methylsyringyl alcohol was studied.By determining the first order reaction rate constants for the oxidation, the main results which were obtained indicate that phenolic lignin structures can be efficiently degraded especially if:A. The pH in the bleaching liquor is close to the pK -valueàfor hydrogen peroxide.B. The ionic strength in the bleaching medium is as high as possible.C. A fixed amount of heavy metal ions (manganese) is added to the bleaching liquor.In the presence of silicate and diethylentriaminepenta-acetic acid (DTPA) hydrogen peroxide is stabilized against decomposition. Under these conditions alkaline hydrogen peroxide is able to react only with lignin units containing conjugated carbonyl groups such as quinone, aryl-oe-carbonyl and cinnamaldehyd structures, leading to an elimination of the chromophoric structures without any substantial dissolution of lignin. In this part of work we have elucidated the kinetic behavior and the reaction products from lignin model compounds of the aryl-of- carbonyl and cinnamaldehyde types.1,2-Diarylpropan-1,3,-diol structures constitute an important building unit in native lignins. We have demonstrated that under hydrogen peroxide bleaching conditions the model compound 2,3--bis(4-hydroxy-3-methoxyphenyl)-3-ethoxy-propanol was converted to stilbenes, ûe. structures which when present in pulps may contribute to a rapid yellowing. The results obtained with model compounds under simulated lignin retaining bleaching conditions demonstrate that there are possibilities to improve the bleaching of mechanical pulps with hydrogen peroxide if:A. The remaining heavy metal ions complexed with DTPA are present in their lowest valence states.B. The concentration of hydroperoxy ions can be maintained at a high level at the lowest possible pH-value.
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| 8. |
- Allergren, Björn, et al.
(författare)
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Studiehandbok
- 1981
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Rapport (övrigt vetenskapligt/konstnärligt)
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| 10. |
- Alm, Håkan, 1948-
(författare)
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Learning of probabilistic inference tasks : effects of uncertainty and function form
- 1982
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is concerned with the problem of how people learn to use uncertain information for making judgments. The general framework for the thesis is Social Judgment Theory (SJT). First the S3T paradigm, and some research conducted within the paradigm, is briefly described, and a series of four empirical studies is summarized. The studies are concerned with two factors that have been found to have great effect on subjects achievement in cue probability learning (CPL) tasks: task predictability, and the form of the function relating cue and criterion. The effects of these two factors were studied in experiments employing cue-probability learning tasks. The studies concerned with task predictability addressed the following questions (a) Do subjects understand the probabilistic nature of CPL-tasks? (b) Are subjects able to detect that a random task is, in fact, random, a study undertaken to test an aspect of Seligmans "theory of helplessness". This was also an attempt to bring emotional factors more in foeus.(c) Do subjects use data from the task only to test hypotheses, or do they use data also to construct hypotheses?The results showed that (a) subjects do not seem to be able to cope with probabilistic tasks in an optimal statistical manner. Instead they seem to use a deterministic approach to the tasks, because they do not understand the probabilistic nature of the task, (b) Task predictability affecs subjects mood, but not in the way predicted by Seligman, (c) Subjects seem to use data frorn the task only to test their hypotheses. The results thus supported the hypotheses sampling model for the learning of CPL-tasks.As for the factor of function form, the following questions were addressed, (a) What hypotheses about relations between variables do subjects have? (b) Is the difficulties subjects have in learning complex rules in CPL-tasks due to a low availability of hypotheses about complex rules? The results showed that, (a) the hypothesis hierarchy as revealed in the present experiments was in general agreement with earlier results. However, few nonlinear hypotheses were observed, and other rules than functional rules were observed, (b) The difficulties subjects have to learn complex rules in CPL-tasks do not seem to be caused by low availability of rules.Finally, some suggestions are given for how the SJT-paradigm should be developed. Specifically, it is suggested that the effects of emotional factors should be given more attention, and that the paradigm should be turned into a more general hypothesis testing model
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