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  • 1.
    Alatalo, Juha
    Göteborgs Universitet.
    Gender lability in trioecious Silene acaulis (Caryophyllaceae)1997In: Nordic Journal of Botany, ISSN 0107-055X, E-ISSN 1756-1051, Vol. 17, no 2, p. 181-183Article in journal (Refereed)
    Abstract [en]

    Gender expression of individual cushions of Silene acaulis was shown to vary between years. Fifteen of thirty-nine (= 38%) cushions monitored changed gender expression between 1993 and 1995. Cushions dominated by female flowers were shown to be more stable in gender expression than cushions dominated by male or hermaphrodite flowers.

  • 2.
    Alatalo, Juha
    et al.
    Göteborgs Universitet.
    Molau, U
    Pollen viability and limitation of seed production in a population of the circumpolar cushion plant, Silene acaulis (Caryophyllaceae)2001In: Nordic Journal of Botany, ISSN 0107-055X, E-ISSN 1756-1051, Vol. 21, no 4, p. 365-372Article in journal (Refereed)
    Abstract [en]

    Pollen viability among genders and limitation of female seed production in a natural trioecious population of the circumpolar cushion plant Silene acaulis was examined. Pollen viability was estimated by an in vitro pollen germination experiment. Both male and hermaphrodite flowers displayed large variation in pollen viability (0-53% in hermaphrodite and 0-54% in male flowers). There was a significant difference between genders in pollen viability: male plants had on average higher pollen viability than hermaphrodite plants. Resource and pollen limitation of seed production was studied by an experiment consisting of three treatments; (I) hand-pollination and removal of all other flowers on the cushion, (II) harid-pollination without removal of other flowers, and (III) open pollination without removal of flowers, Hand-pollination increased seed production, whereas removal of flowers had no effect on seed production. Abortion of pollinated ovules during seed development and seed mass did not differ among treatments. To control for effect of fruit number on seed production, data from naturally pollinated individuals was used. There was a positive correlation between both total number of seeds and fruit number, mean seed number per fruit and fruit number, respectively. These results indicate that seed production of S. acaulis is mainly limited by pollen availability whereas resource competition between fruits is not important as a limiting factor. The possible role of male quality differences between genders and pollen limitation of seed production for maintenance of trioecious reproductive systems is discussed.

  • 3.
    Alatalo, Juha
    et al.
    Göteborgs Universitet.
    Totland, O
    Response to simulated climatic change in an alpine and subarctic pollen-risk strategist, Silene acaulis1997In: Global Change Biology, ISSN 1365-2486, Vol. 3, p. 74-79Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to test if early no overing species respond with increased seed production to climate warming as is predicted for late-flowering seed-risk strategists. Experimental climate warming of about 3 degrees C was applied to two populations of the cushion-forming plant Silene acaulis (L.) Jacq. The experiment was run at one subarctic site and one alpine site for 2 years and 1 year, respectively, using open-top chambers (OTC). The 2-year temperature enhancement at the subarctic site had a marked effect on the flowering phenology. Cushions inside the OTC started flowering substantially earlier than control cushions. Both the male and female phases developed faster in the OTCs, and maturation of capsules occurred earlier. The cushions also responded positively in reproductive terms and produced more mature seeds and had a higher seed/ovule ratio. After 1 year temperature enhancement at the alpine site there was a weak trend for earlier flowering, but there was no significant difference in seed production or seed/ovule ratio.

  • 4.
    Aldén, Anna
    et al.
    University of Kalmar, Sweden.
    Gonzalez, Lorena
    University of Kalmar, Sweden.
    Persson, Anna
    Ellco Food, Sweden.
    Christensson, Kerstin
    Mälardalen University, School of Health, Care and Social Welfare. Ellco Food, Sweden.
    Holmqvist, Olov
    ProLiff AB, Sweden.
    Ohlson, Sten
    University of Kalmar, Sweden.
    Porcine platelet lysate as a supplement for animal cell culture2007In: Cytotechnology (Dordrecht), ISSN 0920-9069, E-ISSN 1573-0778, Vol. 55, no 1, p. 3-8Article in journal (Refereed)
    Abstract [en]

    A novel supplementation of cell growth media based on a porcine platelet lysate was developed for culture of animal-derived cells. The platelet lysate was produced from porcine blood and contained lysate of platelets and plasma components. It showed satisfactory microbiological integrity and it carried only low amount of endotoxins (<10 EU/mL). The porcine platelet lysate supported well proliferation of Vero (African green monkey transformed kidney epithelial cells), Chinese hamster ovary (CHO) and hybridoma cells comparable to fetal bovine serum (FBS). Platelet lysate shows promise as a viable choice over FBS as it can be produced in large quantities, high lot-to-lot consistency and with an attractive price structure. Furthermore it is a strong alternative to FBS for ethical reasons. It is expected that it can be used as a general supplementation for most animal cells for research studies on the proliferation of cells and their expression of products.

  • 5.
    Altola, Juha
    et al.
    Göteborgs Universitet.
    MOLAU, U
    EFFECT OF ALTITUDE ON THE SEX-RATIO IN POPULATIONS OF SILENE ACAULIS (CARYOPHYLLACEAE)1995In: Nordic Journal of Botany, ISSN 0107-055X, E-ISSN 1756-1051, Vol. 15, no 3, p. 251-256Article in journal (Refereed)
    Abstract [en]

    Predicted increase of female frequencies in gynodioecious Silene acaulis was tested along an altitude gradient in northern Sweden. Average female frequencies for the four sites increased with altitude from 42% to 59% within a short geographical distance. This follows the outcrossing hypothesis, that female frequencies should be positively correlated with selfing rates of hermaphrodites in populations. More adverse environmental conditions should favour gynodioecy in areas where reproduction to a greater part relies on vegetative reproduction or selfing. Further, a significant difference in corolla width was found between females and the larger hermaphrodites, but not between sites. Cushion size and the number of flowers per cushion decreased with altitude.

  • 6.
    Arft, M
    et al.
    Univ Colorado.
    Walker, D
    Gurevitch, J
    Alatalo, Juha
    Göteborgs Universitet.
    Bret-Harte, S
    Dale, M
    Diemer, M
    Gugerli, F
    Henry, R
    Jones, H
    Hollister, D
    Jonsdottir, S
    Laine, K
    Levesque, E
    Marion, M
    Molau, U
    Molgaard, P
    Nordenhall, U
    Raszhivin, V
    Robinson, H
    Starr, G
    Stenstrom, A
    Stenstrom, M
    Totland, O
    Turner, L
    Walker, J
    Webber, J
    Welker, M
    Wookey, A
    Responses of tundra plants to experimental warming: Meta-analysis of the international tundra experiment1999In: Ecological Monographs, ISSN 0012-9615, Vol. 69, no 4, p. 491-511Article in journal (Refereed)
    Abstract [en]

    The International Tundra Experiment (ITEX) is a collaborative, multisite experiment using a common temperature manipulation to examine variability in species response across climatic and geographic gradients of tundra ecosystems. ITEX was designed specifically to examine variability in arctic and alpine species response to increased temperature. We compiled from one to four years of experimental data from 13 different ITEX sites and used meta-analysis to analyze responses of plant phenology, growth, and reproduction to experimental warming. Results indicate that key phenological events such as leaf bud burst and flowering occurred earlier in warmed plots throughout the study period; however, there was little impact on growth cessation at the end of the season. Quantitative measures of vegetative growth were greatest in warmed plots in the early years of the experiment, whereas reproductive effort and success increased in later years. A shift away from vegetative growth and toward reproductive effort and success in the fourth treatment year suggests a shift from the initial response to a secondary response. The change in vegetative response may be due to depletion of stored plant reserves, whereas the lag in reproductive response may be due to the formation of flower buds one to several seasons prior to flowering. Both vegetative and reproductive responses varied among life-forms; herbaceous forms had stronger and more consistent vegetative growth responses than did woody forms. The greater responsiveness of the herbaceous forms may be attributed to their more flexible morphology and to their relatively greater proportion of stored plant reserves. Finally, warmer, low arctic sites produced the strongest growth responses, but colder sites produced a greater reproductive response. Greater resource investment in vegetative growth may be a conservative strategy in the Low Arctic, where there is more competition for light, nutrients, or water, and there may be little opportunity for successful germination or seedling development. In contrast, in the High Arctic, heavy investment in producing seed under a higher temperature scenario may provide an opportunity for species to colonize patches of unvegetated ground. The observed differential response to warming suggests that the primary forces driving the response vary across climatic zones, functional groups, and through time.

  • 7.
    Backlund, Mari
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Fiskfaunan i Ekeby våtmark2008Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Fiskfaunan i Ekeby våtmark inventerades med hjälp av två metoder, fångst-återfångst och nätprovfiske, som i möjligaste mån använde metodiken vid standardiserat provfiske. Med fångst-återfångst metoden fångade jag sutare, abborre och småspigg, dock var fångsten av abborre och småspigg så liten att det inte kunde göras någon uppskattning av dessa populationsstorlekar. Uppskattningen av sutarnas populationsstorlek i damm 8 erhölls efter ett antal fångst och märkningstillfällen tills det fanns tillräckligt stor andel återfångst av sutare. De mjärdar som användes kunde bara fånga fisk av ett visst storleksintervall (35-120 mm) vilket troligtvis betyder att det enbart fångades 1- och 2-åriga sutare. Min uppskattning av antalet individer i populationen sutare (Lincoln Index) blev 1316 +/- 1127. Det insamlade materialet från nätprovfisket jämfördes med Fiskeriverkets referensmaterial. Den infångade fisken vägdes och mättes enligt den standardiserade metoden för provfiske. Fiskarnas kondition kalkylerades som Fultons konditionsindex. Konditionen hos abborre och mört var signifikant högre i Ekeby våtmark jämfört med referensvärdena. Hos abborre fanns signifikanta skillnader i längd och vikt, som var högre i damm 8 än i damm 6, men ingen signifikant skillnad i kondition mellan dammarna. Hos mört fanns det liknande signifikanta skillnader mellan dammarna, där längd och vikt var högre i damm 8 än i damm 6, men här är även skillnaden i kondition signifikant, då den var högre i damm 8 än i damm 6. Uppgifter från referensmaterialet användes för att bedöma åldersklasser i mitt material. Vid nätfångsten påträffades en anmärkningsvärt rik förekomst av en typ av parasit som observerades som svarta fläckar på mört och sarv. Parasiteringsgrad, d v s antal svarta fläckar, var korrelerad med fiskens vikt och totallängd, vilket var signifikant hos mört (p<0.01)

  • 8.
    Bannoura, Jeries
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Identifiering av insektsöverförda organismer i blod hos klövvilt.: Undersökning, bestämning och identifiering av Rickettsia och Trypanosoma i blod hos vilda klövdjur i Södermanlan, Sverige.2010Independent thesis Basic level (university diploma), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    Med hjälp av molekylärbiologiska tekniker, bland annat nested PCR tekniken, bestämdes och identifierades parasit- och bakteriearter i blodprover från rådjur, älg, dovhjort, kronhjort och vildsvin i Södermanland, Sverige.Total-DNA extraherades ur blodprover, vilka fanns insamlade från jakt i centrala Södermanland. Med hjälp av specifikt designerade primers kördes nested PCR.

    Jag koncentrerade mig på den protista paratisen Trypanosoma theileri samt på intracellulära Rickettsia bakterier. PCR reaktionerna analyserades med hjälp av gel elektrofores. Negativa kontroller inkluderades i alla PCR försök för att undvika falska positiva resultat, något som är viktigt vid arbete med nested PCR. Positiva kontroller användes också för att vara säker på att storleker av PCR produkter är rätta.

     För att bestämma protist och bakterie till artnivå krävs att man DNA- sekvenserar de PCR positiva produkterna, det vill säga de DNA-fragment som amplifierats.PCR positiva produkter renades för att bli av med komponenter som till exempel primers eller ospecifika amplifikat som kan störa sekvens reaktionen.

     Sekvenseringsreaktion enligt Sanger utfördes med hjälp av ”cykel-sekvensering”. Därefter precipiterades DNA fragmenten med Etanol/EDTA/natriumacetat och torkades.

    Proverna skickades sedan till Karolinska institutet för sekvensbestämning.De erhållna sekvenserna alignerades med programmet ”BLAST”, i NCBI (National Center for Biotechnology Information) därmed kunde de sökta parasit- och bakteriearterna identifieras.

     

  • 9.
    Bech, Linda
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Genetic and phenotypic characterization of trypanosomas2009Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

     

    Trypanosoma theileri, of the subgenus Megatrypanum, a non-pathogenic cosmopolitan blood dwelling parasite of bovine. T. theileri can be cultured at room temperature in several culture media.

    Blood samples were collected from deer's. To see if the blood was infected with trypanosomes it was cultivated in 2 ml sheep blood or cell cultivation medium DMEM with antibiotics.

    Growth was detected by microscopy to see if there were any trypanosomes.

    To determine the species of trypanosomes that was in the deer blood a DNA-preparation was done before a Polymerase Chain Reaction (PCR) could be done. With sequencing the trypanosomes where determined to be Trypanosoma theileri.

    Different tests were made to see in what way the trypanosomes best were caught to the objective slides.

    Forty samples of borrelia positive serum from forty different patients were tested with the fluorescent microscopy. Forty different samples from blood donors were tested the same way.

    Blood samples from 16 different fissiped were taken and to see if they were infected with trypanosomes. Three different PCR's were done on the 16 blood samples.

    A small test on human blood was also performed.

    Protein identification by immunoblot with western blot and silver staining was done.

    With the electron microscopy tests were done in the ordinary way and Critical Dry Point to see if both of the techniques worked.

    Enzyme-Linked Immuno Sorbent Assay (ELISA) test were accomplished on two 96 well plates. The wells on the plates were diluted in different ways before they were processed.

     

     

  • 10.
    Berna, Nathalie
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Berna, P
    Uppsala University, Sweden.
    Oscarsson, Sven
    Mälardalen University, Department of Biology and Chemical Engineering.
    Cosolvent-induced adsorption and desorption of serum proteins on an amphiphilic mercaptomethylene pyridine-derivatized agarose gel1996In: Arch Biochem Biophys, ISSN 0003-9861, Vol. 330, no 1, p. 188-192Article in journal (Refereed)
    Abstract [en]

    We studied the effects of the following cosolvents on the adsorption and desorption of serum proteins from an amphiphilic mercaptomethylene pyridine-derivatized agarose gel: glucose, sucrose, polyethylene glycol (PEG), 2-methyl-2,4-pentanediol (MFD), sorbitol, pentaerythritol, glycerol, and Na2SO4. The water-structuring salt 0.4 M Na2SO4 was the most potent promoter of protein adsorption, followed by 5 M sorbitol and, to a lesser extent, 0.2 M PEG 1000 and 2.25 M MPD. The other cosolvents (4 M glucose, 1.5 M sucrose, 0.3 M pentaerythritol, and 7.6 M glycerol) were unable to promote protein adsorption to the gel. Attempts to modulate the salt-promotion effect of Na2SO4 with different cosolvents demonstrated the occurrence of synergistic effects for pentaerythritol, sorbitol, and glucose and antagonistic effects for the other cosolvents. Sorbitol and glycerol were found to be the most interesting co-solvents studied, as the first promoted protein adsorption, whereas the other disrupted protein interaction. As a consequence of these novel findings we propose sorbitol and glycerol, both well-known protein stabilizers, as possible alternatives to water-structuring salts during the adsorption phase and to deleterious organic solvents during the desorption phase on amphiphilic gels.

  • 11.
    Buijs, J
    et al.
    Biacore AB, Sweden.
    Franklin, C.G.
    Biacore AB, Sweden.
    SPR-MS in Functional Proteomics2005In: Briefings in Functional Genomics and Proteomics, ISSN 1473-9550, Vol. 4, no 1, p. 39-47Article in journal (Refereed)
    Abstract [en]

    The mapping of protein networks and the establishment of the functional relationships between expressed proteins and their effects on cellular processes represents a great challenge for functional or interaction proteomics. The combination of surface plasmon resonance (SPR)-based technology with mass spectrometry (MS) has created a unique analytical tool for functional proteomics investigations. Proteins are affinity purified, quantified and characterised in terms of their interactions, while the mass spectrometer identifies and structurally characterises the biomolecules. Recent developments have led to a closer integration of these key technologies, providing a combined approach which enables identification of proteins selected on the basis of their functional binding criteria. In addition to a historical overview of this field, some recent detailed examples of combined SPR-MS approaches will be reviewed in a number of key application areas, including ligand fishing, peptide sequence and post-translational modification analysis by SPR-MS/MS and enzyme inhibitor screening.

  • 12.
    Buijs, Jos
    et al.
    Uppsala University, Sweden.
    Ramström, Margareta
    Uppsala University, Sweden.
    Danfelter, Mikael
    Uppsala University, Sweden.
    Larsericsdotter, Helén
    Mälardalen University, Department of Biology and Chemical Engineering.
    Håkansson, Per
    Mälardalen University, Department of Biology and Chemical Engineering.
    Oscarsson, Sven
    Mälardalen University, Department of Biology and Chemical Engineering.
    Localized changes in the structural stability of myoglobin upon adsorption onto silica particles, as studied with hydrogen/deuterium exchange mass spectrometry2003In: Journal of Colloid and Interface Science, ISSN 0021-9797, Vol. 263, no 2, p. 441-448Article in journal (Refereed)
    Abstract [en]

    A new method is presented for monitoring the conformational stability of various parts of a protein that is physically adsorbed onto nanometer-sized silica particles. The method employs hydrogen/deuterium (H/D) exchange of amide hydrogens, a process that is extremely sensitive to structural features of proteins. The resulting mass increase is analyzed with Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. Higher structural specificity is obtained by enzymatically cleaving the adsorbed proteins prior to mass spectrometric analysis. The mass increases of four peptic fragments of myoglobin are followed as a function of the H/D exchange time. The four peptic fragments cover 90% of the myoglobin structure. Two of the peptic fragments, located in the middle of the myoglobin sequence and close to the heme group, do not show any adsorption-induced changes in their structural stability, whereas the more stable C- and N-terminal fragments are destabilized. Interestingly, for the N-terminal fragment, comprising residues 1–29, two distinct and equally large conformational populations are observed. One of these populations has a stability similar to that in solution (−23 kJ/mol), whereas the other population is highly destabilized upon adsorption (−11 kJ/mol).

  • 13.
    Bystricka, Marketa
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Nattaktivitet hos Dvärgflodhästar (Hexaprotondon liberiensis) på Parken Zoo i Eskilstuna våren 2010.2010Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Dvärgflodhästen (Hexaprotondon liberiensis) lever i Västafrika där den upptäcktes på 1800-talet, men det var inte förrän på 1900- talen som de introducerades första gången i djurpark. Studier på vilda dvärgflodhästen har visat sig vara svåra att genomföra, därför har de flesta studier gjorts på dvärgflodhästar i fångenskap. Dvärgflodhästen är ett mycket skyggt djur som lever i regnskogarna runt floder, träsk och sumpmarker. Den är ett nattlevande djur som ofta lever solitärt.

     

    I den här studien studeras tre utvalda dvärgflodhästar på parken zoo i Eskilstuna, vad de har för nattaktivitet och hur de använder sig utav miljöberikningen. Leah, Anton och Krakunia var de tre observerade dvärgflodhästarna.

       

    Videokameror sattes upp för att filma fyra nätter för varje individ från kl. 16.00- 03.00. Ett protokoll fördes vart tionde minut och deras aktivitet antecknades. Dessa resultat sammanställdes i beskrivande text och jämfördes sedan med varandra i diagram. Diagram visade bland annat att Leah använde sin pool mest av alla, Anton var den mest aktiva och nyfikna medan Krakunia knappt rörde sin miljöberikning.

     

    Varför finns dessa skillnader? Har deras ålder, kön eller utseende på rummet någon betydelse? Hur skulle man kunna förbättra miljöberikningen i dvärgflodhästarnas rum? Eftersom de är utrotningshotade är det viktigt att man gör några åtgärder och försöker bevara deras naturliga miljö i den mån det är möjligt. Kan man med hjälp av djurparken återinföra dvärgflodhästar i naturen? Enligt en artikel skulle det kunna vara möjligt.

     

  • 14.
    Carlsson, Linett
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Activity and enclosure use of a sand cat in Parken Zoo, Eskilstuna2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The escalating extinction of wildlife puts a high pressure on the standard of ex situ conservation. Some animals may spend several generations in captivity which may affect their natural behaviors and also a future reintroduction into the wild. Observations of animal behavior among captive animals are crucial for the understanding of ex situ conservation effects on behavior and in order to introduce and improve environmental enrichment. This study investigates activity and enclosure use of a sand cat (Felis margarita) at Parken zoo in Eskilstuna Sweden. Direct observations of behavior and movements were carried out and audience impact was also analyzed. The sand cat in the present study showed no behavioural response to the audience but it had some effect on his location in the enclosure. I also found that he was more active during late afternoon after feeding time and that he slept most during the forenoon. He used the whole enclosure to some extent but he spent most of his time in the cave, the front and the middle of the enclosure. Although he did not show any typical stereotypic behavior he had some odd habits that could probably be prevented through environmental enrichment.

  • 15.
    Chaudhary, Ramjee
    et al.
    Indian Inst Technol, Ctr Environm Sci & Engn, Mumbai 400076, Maharashtra, India.;Natl Univ Singapore, Dept Chem & Biomol Engn, Singapore 117576, Singapore..
    Dikshit, Anil Kumar
    Mälardalen University. Indian Inst Technol, Ctr Environm Sci & Engn, Mumbai 400076, Maharashtra, India.;Malardalen Univ, Sch Business Environm & Soc, Vasteras, Sweden.;Asian Inst Technol, Sch Environm Resources & Dev, Urban Environm Management, Pathum Thani 12120, Thailand..
    Tong, Yen Wah
    Natl Univ Singapore, Dept Chem & Biomol Engn, Singapore 117576, Singapore.;Natl Univ Singapore, Environm Res Inst, Singapore, Singapore..
    Carbon-dioxide biofixation and phycoremediation of municipal wastewater using Chlorella vulgaris and Scenedesmus obliquus2018In: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 25, no 21, p. 20399-20406Article in journal (Refereed)
    Abstract [en]

    The pure cultures of microalgae Chlorella vulgaris ATCC 13482 and Scenedesmus obliquus FACHB 417 were grown in municipal wastewater in 7-L airlift bubble column photobioreactor supplied with 5% CO2/air (v/v). Batch experiments were conducted at 25 A degrees C with 14-h light/10-h dark cycle for a period of 10 days. The CO2 capture efficiencies for both the microalgae were monitored in terms of their respective biomass productivities, carbon contents, and CO2 consumption rates. In the present study, the initial concentration of ammonia (43.7 mg L-1) was decreased to 2.9 and 3.7 mg L-1 by C. vulgaris and S. obliquus, respectively. And, the initial concentration of phosphate (18.5 mg L-1) was decreased to 1.1 and 1.6 mg L-1 by C. vulgaris and S. obliquus, respectively. CO2 biofixation rates by C. vulgaris and S. obliquus, cultivated in municipal wastewater, were calculated to be 140.91 and 129.82 mg L-1 day(-1), respectively. The findings from the present study highlight the use of microalgae for wastewater treatment along with CO2 uptake and biomass utilization for pilot scale production of biodiesel, biogas, feed supplements for animals, etc., thus minimizing the production costs.

  • 16.
    Cornelissen, C
    et al.
    Vrije Univ Amsterdam.
    Callaghan, V
    Alatalo, Juha
    Göteborgs Universitet.
    Michelsen, A
    Graglia, E
    Hartley, E
    Hik, S
    Hobbie, E
    Press, C
    Robinson, H
    Henry, R
    Shaver, R
    Phoenix, K
    Jones, G
    Jonasson, S
    Chapin, S
    Molau, U
    Neill, C
    Lee, A
    Melillo, M
    Sveinbjornsson, B
    Aerts, R
    Global change and arctic ecosystems: is lichen decline a function of increases in vascular plant biomass?2001In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 89, no 6, p. 984-994Article in journal (Refereed)
    Abstract [en]

    1 Macrolichens are important for the functioning and biodiversity of cold northern ecosystems and their reindeer-based cultures and economics. 2 We hypothesized that, in climatically milder parts of the Arctic, where ecosystems have relatively dense plant canopies, climate warming and/or increased nutrient availability leads to decline in macrolichen abundance as a function of increased abundance of vascular plants. In more open high-arctic or arctic-alpine plant communities such a relationship should be absent. To test this, we synthesized cross-continental arctic vegetation data from ecosystem manipulation experiments simulating mostly warming and increased nutrient availability, and compared these with similar data from natural environmental gradients. 3 Regressions between abundance or biomass of macrolichens and vascular plants were consistently negative across the subarctic and mid-arctic experimental studies. Such a pattern did not emerge in the coldest high-arctic or arctic-alpine sites. The slopes of the negative regressions increased across 10 sites as the climate became milder (as indicated by a simple climatic index) or the vegetation denser (greater site above-ground biomass). 4 Seven natural vegetation gradients in the lower-altitude sub- and mid-arctic zone confirmed the patterns seen in the experimental studies, showing consistent negative relationships between abundance of macrolichens and vascular plants. 5 We conclude that the data supported the hypothesis. Macrolichens in climatically milder arctic ecosystems may decline if and where global changes cause vascular plants to increase in abundance. 6 However, a refining of our findings is needed, for instance by integrating other abiotic and biotic effects such as reindeer grazing feedback on the balance between vascular plants and lichens.

  • 17.
    Ehn, Micael
    Mälardalen University, School of Education, Culture and Communication.
    Specialization leads to feedback cycles in cultural evolutionManuscript (preprint) (Other academic)
    Abstract [en]

    This paper studies the interaction between specialization and cul-tural evolution. Four key components are identified from publishedempirical studies: Culture, Specialization, Production and Popula-tion. Mathematical models are used to investigate the interactionsbetween the components and the behavior of the entire system. Theresults show that specialization is both a cause and an outcome of cul-tural cumulation, which creates feedback cycles in cultural evolution.The feedback cycles can explain the drastic increase in innovation ratewe have observed throughout human history. Specialization is there-fore argued to be an integral part in understanding cultural evolution.

  • 18.
    Ehn, Micael
    Mälardalen University, School of Education, Culture and Communication.
    Under what circumstances can copying lead to increased cultural diversity?Manuscript (preprint) (Other academic)
    Abstract [en]

    In many models of cultural evolution, agents learn cultural elements either by individual learning (innovation) or social learning (copying). This paper investigates what kind of learning, or combination of the two kinds, maximizes the total number of cultural elements known in the population. In a model where both kinds of learning are equally efficient, we find that this maximum is achieved when only individual learning is used. Analysis and simulation is used to investigate how much more efficient social learning has to be for a mixed solution to appear. Two possible reasons for social learning being more efficient than innovation are identified.

  • 19.
    Ehn, Micael
    et al.
    Mälardalen University, School of Education, Culture and Communication.
    Laland, Kevin
    University of St Andrews.
    Adaptive Strategies for Cumulative Cultural LearningManuscript (preprint) (Other academic)
    Abstract [en]

    The demographic and ecological success of our species is frequently attributed to our capacity for cumulative culture. However, it is not yet known how humans combine social and asocial learning to generate effective strategies for learning in a cumulative cultural context. Here we explore how cumulative culture influences therelative merits of various pure and conditional learning strategies, including pure asocial and social learning, critical social learning, conditional social learning and individual refiner strategies. We replicate the Rogers’ paradox in the cumulative setting. However, our analysis suggests that strategies that resolved Rogers’ Paradoxin a non-cumulative setting may not necessarily evolve in a cumulative setting, thus different strategies will optimize cumulative and non-cumulative cultural learning.

  • 20.
    Ehn, Micael
    et al.
    Mälardalen University, School of Education, Culture and Communication. Stockholms universitet, Centrum för evolutionär kulturforskning.
    Laland, Kevin
    Stockholm University.
    Adaptive strategies for cumulative cultural learning2012In: Journal of Theoretical Biology, ISSN 0022-5193, E-ISSN 1095-8541, Vol. 301, p. 103-111Article in journal (Refereed)
    Abstract [en]

    The demographic and ecological success of our species is frequently attributed to our capacity for cumulative culture. However, it is not yet known how humans combine social and asocial learning to generate effective strategies for learning in a cumulative cultural context. Here we explore how cumulative culture influences the relative merits of various pure and conditional learning strategies, including pure asocial and social learning, critical social learning, conditional social learning and individual refiner strategies. We replicate the Rogers' paradox in the cumulative setting. However, our analysis suggests that strategies that resolved Rogers' paradox in a non-cumulative setting may not necessarily evolve in a cumulative setting, thus different strategies will optimize cumulative and non-cumulative cultural learning.

  • 21.
    Ekaterina, van der Haagen
    Mälardalen University, Department of Biology and Chemical Engineering.
    ”Processutveckling av metod f?r tillverkning av en funktionell tibetansk mejeriprodukt”2009Independent thesis Advanced level (professional degree), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    Probiotics is a special group of health products on the market. The most common type of  these is live cultures of lactic acid fermenting bacteria from raw milk . These include, among others, yogurt and various trademarks such as Hälsofil ®, Acidophilus ®, Dofilus ® and Kefir ®. Such products are often used by patients who are treated with antibiotics to combat the intestinal flora eliminated, thus causing digestive problems. The present work deals with yet another type of health product, viz. kefir of Tibetan type. A literature review of mainly Russian sources has been made to identify the nutrients and potential health benefits of kefir consumption in humans. The study sought to find data on the nutritional values of this very particular culture of a certain fungus, Zoogloea ramigera and some species of the genus Lactobacillus. However, this has not been found other than the data on the product, which is on the Swedish market under the brand Kefir, which is a product of a different nature than the Tibetan form of kefir. One source indicates, however, that among other things, it contains vitamin D, which would otherwise break down in this type of product. Part of the work is a study of the characteristics of the kefir culture for an intended technological process of production. The study shows that culture can be stored while maintaining viability by freezing to -70 ⁰ C. The culture is not affected by Gentamycin, which is a common antibiotic. Kefir culture tends to grow in the form of granules or lumps, which may be separated and reused for production. It is sensitive to metal ions, so that process equipment, intended for contact with kefir must be manufactured from other materials such as enamel or polymer-coated steel sheets. A study of cultural interaction with three different strains of intestinal bacteria showed very little impact on the cultivation on agar plate. In batch fermentation the pH of the kefir culture decreases to 3.4, which is slightly higher than the pKa of lactic acid. This pH is unfavorable for disease-causing bacteria and can be expected to limit growth of those in the human gastrointestinal tract upon ingestion.

  • 22.
    Enquist, Magnus
    et al.
    Stockholm University.
    Strimling, Pontus
    Stockholm University.
    Eriksson, Kimmo
    Mälardalen University, School of Education, Culture and Communication.
    Laland, Kevin
    University of St Andrews.
    Sjöstrand, Jonas
    Stockholm University.
    One cultural parent makes no culture2010In: Animal Behaviour, ISSN 0003-3472, E-ISSN 1095-8282, Vol. 79, no 6, p. 1353-1362Article in journal (Refereed)
    Abstract [en]

    The ability to acquire knowledge and skills from others is widespread in animals and is commonly thought to be responsible for the behavioural traditions observed in many species. However, in spite of the extensive literature on theoretical analyses and empirical studies of social learning, little attention has been given to whether individuals acquire knowledge from a single individual or multiple models. Researchers commonly refer to instances of sons learning from fathers, or daughters from mothers, while theoreticians have constructed models of uniparental transmission, with little consideration of whether such restricted modes of transmission are actually feasible. We used mathematical models to demonstrate that the conditions under which learning from a single cultural parent can lead to stable culture are surprisingly restricted ( the same reasoning applies to a single social-learning event). Conversely, we demonstrate how learning from more than one cultural parent can establish culture, and find that cultural traits will reach a nonzero equilibrium in the population provided the product of the fidelity of social learning and the number of cultural parents exceeds 1. We discuss the implications of the analysis for interpreting various findings in the animal social-learning literature, as well as the unique features of human culture.

  • 23.
    Eriksson, Kimmo
    Mälardalen University, Department of Mathematics and Physics.
    Ethnographic stories of cooperation and algebraic stories of evolution2007In: Journal of Evolutionary Psychology, ISSN 0737-4828, Vol. 5, no 1-4, p. 245-250Article, book review (Other (popular science, discussion, etc.))
  • 24.
    Eriksson, Kimmo
    et al.
    Mälardalen University, School of Education, Culture and Communication, Educational Sciences and Mathematics. Stockholm Univ, Stockholm, Sweden.
    Cownden, Daniel
    Stockholm Univ, Stockholm, Sweden.
    Strimling, Pontus
    Stockholm Univ, Stockholm, Sweden.
    Social learning may lead to population level conformity without individual level frequency bias2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 17341Article in journal (Refereed)
    Abstract [en]

    A requirement of culture, whether animal or human, is some degree of conformity of behavior within populations. Researchers of gene-culture coevolution have suggested that population level conformity may result from frequency-biased social learning: individuals sampling multiple role models and preferentially adopting the majority behavior in the sample. When learning from a single role model, frequency-bias is not possible. We show why a population-level trend, either conformist or anticonformist, may nonetheless be almost inevitable in a population of individuals that learn through social enhancement, that is, using observations of others' behavior to update their own probability of using a behavior in the future. The exact specification of individuals' updating rule determines the direction of the trend. These results offer a new interpretation of previous findings from simulations of social enhancement in combination with reinforcement learning, and demonstrate how results of dynamical models may strongly depend on seemingly innocuous choices of model specifications, and how important it is to obtain empirical data on which to base such choices.

  • 25.
    Fischer, Torkel
    Mälardalen University. Mälardalen University, School of Sustainable Development of Society and Technology. Mälardalen University, Department of Biology and Chemical Engineering.
    Boplatsval hos solitära getingar, bin och rovsteklar2009Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Denna undersökning gjordes för att studera solitära steklars boplatsval speciellt med avseende på spatiala mönster. Aggregat av lämpliga bohål (bibatterier) tillverkades och gjordes tillgängliga förfrilevande steklar. Resultatet visade att steklar tenderar att anlägga bon i närheten av andra stekelbon. Ingen tendens fanns att anlägga bon i centralt belägna positioner. Steklarna verkar också föredra att anlägga bon till vänster om en tänkt mittllinje på bibatterierna. Aggregation kan vara ett sätt att undgå parasitering och predation vid boplatsen. Om detta orsakade aggregationstendensen var det dock något oväntat att inte också en central tendens kunde påvisas. Att steklarna föredrog bohål i bibatteriernas vänstra del är svårt att förklara.

  • 26.
    Gajardo Gunnarsson, Tania
    Mälardalen University, Department of Biology and Chemical Engineering.
    identifiering av genetisk markör för könsbestämning av Gasterousteus aculeatus2008Independent thesis Advanced level (degree of Magister), 20 points / 30 hpStudent thesis
    Abstract [sv]

    Arbetets uppgift var att identifiera en DNA-sekvens som skulle kunna finnas hos storspiggens könsbestämningsregion. Avsikten med detta arbete är att utveckla en enkel PCR-baserad metod för att kunna könsbestämma storspiggar genetiskt. Tidigare genetiska studier har visat en skillnad mellan honor och hanar vid jämförelse av deras RAPD-3 PCR produkter. Skillnaden består i att endast hanarna har ett fragment som är runt 250 bp stort. Detta fragment ska isoleras, renas, klonas och sekvenseras med hjälp av olika metoder. Sekvensen ska användas för att beställa designerade primer som testades för att vara specifika för hanar.

    I detta arbete kunde endast en sekvens användas för detta syfte och två egendesignerade primers beställdes, dessa visade sig dock icke vara specifika för hanar.

  • 27.
    Ghalali, Aram
    Mälardalen University, Department of Biology and Chemical Engineering. Mälardalen University, School of Sustainable Development of Society and Technology.
    STATINS AND INCREASED EFFICACY OF CANCER TREATMENT2008Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Abstract

    Activation of the PI3K/Akt signaling cascade is often associated with advanced forms of prostate cancer cells, DU145. This is likely explained by the common loss of the PTEN gene in majority of cancer cells. This study have documented that low concentration of atorvastatin, a drug inhibiting HMG-CoA reductase and cholesterol metabolism, decreased the level of insulin-induced phosphorylated Akt in the nucleus.

    The statins effect on Akt/protein kinase B signaling and the sensitizing effect of cytostatic drugs have been investigated in this study and it were found that cytostatic drugs induced Akt phosphorylation and nuclear translocation was inhibited by atorvastatin in A549 and DU145 cells. Inhibition of PI3K with LY294002 was observed by MTT assay, and it were noticed that atorvastatin increased the effect of LY294002.

    The main point of the study was the localization of the tumor suppressor PTEN. This gene acts as a plasma-membrane lipid-phosphatase antagonizing the phosphoinositide 3-kinase/Akt cell survival pathway. The nuclear localization of PTEN is a central for its activity. The insulin-induced A549 cells were treated with atorvastatin, thereafter very rapid change in PTEN localization was observed.

    The study is preformed in view of good laboratory practice, GLP. In this study GLP applies to non-clinical experiment conducted for the assessment of the safety of chemicals (the concentration of the atorvastatin) to man and the environment.

     

  • 28.
    Gustafsson, Emelie
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Blomqvist, Susanne
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Naturpedagogiskt läromedelFörskoleklass - År 3: Filip upptäcker Rex, Inifrån!2013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Syftet med arbetet var att skapa en naturvetenskaplig faktabaserad sagobok  för barn.

    Vi ville göra detta eftersom vi ansåg att det behövs mer naturvetenskapliga läromedel anpassade för barn i yngr åldrar. Med denna bok var vår förhopp

  • 29.
    Gusén, Anna
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Lillån: Statusbedömning enligt EU:s ramdirektiv för vatten2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In Sweden, the County Administration board is responsible for improving the water quality in lakes and watercourses according to the European Union Water Framework Directive. In Västmanland county, where river Lillån is situated, the County Administration of Västmanland have the main responsibility for the aquatic environment in that area. The knowledge about the different watercourses in the chatchment of river Lillån is today limited. The aim with this study was to evaluate the ecological quality of River Lillån based on water chemistry analyses and benthic fauna investigations. The aim was also for the benthic fauna to compere different samplingsites and sampling methods with each other in order to see how the species composition changes in the river, and to see the advantages and disadvantages with different sampling tecniques. The methods used for the assessment was presented in a handbook composed by the Swedish Environmental Protection Agency. The results of the study showed that Lillån have good quality concerning acidity and the general ecological status. The benthic fauna investigations indicated high levels of nutrients and thereby resulted in poor status concerning that parameter. The conclusion of the study was that river Lillån does not fulfill the criteria of good status according to the Water Framework Direcive composed by the European Union.

     

    Keywords: Water directive, water quality evaulation, benthic fauna, acidification, nutrients, methods for sample-taking.

    Nyckelord: Vattendirektiv, statusbedömning, bottenfauna, försurning, näringsämnen, provtagningsmetoder.

     

  • 30.
    Hamidi, Helaleh
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Effekter av vanadin föreningar på fosfatas i olika celler2006Independent thesis Advanced level (degree of Magister), 10 points / 15 hpStudent thesis
    Abstract [sv]

     

    Enligt tidigare undersökningar har vanadinföreningar visat sig ha insulinliknande effekter både in vitro och in vivo. Syftet med detta examensarbete var att prova ut en teknik för att testa effekten av vanadinföreningar på två olika celltyper: adherenta celler (AA-celler) och suspensionsceller (K562-celler). När insulinet binder till sin receptor på cellytan är det starten på en biologisk respons. Insulinreceptorn är ett tyrosinkinas som transporterar fosfatgrupper från ATP till tyrosin på sin egen peptidkedja. De aktiverade tyrosinkinasreceptorn kan aktivera ett antal signalmolekyler, bland annat proteinkinas B. Tyrosin som är fosfolyserat, defosfolyseras senare av proteinet tyrosinfosfatas (PTP). Insulinets signaleringsvägar är kontrollerade av omvändbar fosforylerings reaktioner. Patogenesis av insulinresistens i typ 2-diabetes och övervikt är sammanlänkade av den normala signaleringens responsen till insulin. I denna studie undersöktes effekten av vanadat och ett antal ligander som bildar komplex med vanadat. Den största vikten lades vid att undersöka vilka koncentrationer av ämnena som var icke-toxiska vid cellodling och därmed inte leder cellerna till apoptos. Först testades att föreningarna inte gav ändring i pH . Därefter testades deras effekter på celler. Med endast vanadat observerades celltoxina effekter vid koncentrationer över 1µM. I nästa steg behandlades AA-cellerna med fyra olika koncentrationer av vanadat tillsammans med olika ligander. K562-celler behandlades bara med vanadat och ligand 2. Resultaten visar att koncentrationer upp till och med 1µM vanadat inte hade några negativa effekter på cellerna. Varken apoptos eller onormal minskning i antal celler observerades. Slutligen testades effekter av vanadatföreningarna på PTP aktiviteten i odlade celler. I kitet som användes fanns detektorn ”Green Reagent” som kan identifiera fritt fosfat genom färgändring från gul till grön. Cellerna behandlades med vanadat och efter 24 timmar gjordes en cellextraktion. Cellextrakten späddas 10 gånger, sedan tillsattes detektorn Green Reagent efter 15 min. Analys gjordes med hjälp av en Elisa-läsare. Resultaten visar att med ökande koncentration av vanadat påverkades cellerna så att PTP 1B aktiviteten ökades. Detta är ett intressant resultat i ljuset av att vanadat rapporterats ha insulinliknande effekt. En tänkbar förklaring är att defosforyleringen av insulinreceptorn krävs för att aktivera insulin responsen i celler.

  • 31.
    Helena, Stärner
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Påhlsson, Carl
    Mälardalen University, Department of Biology and Chemical Engineering.
    Lindén, Mats
    Mälardalen University, Department of Biology and Chemical Engineering.
    Tandem repeat polymorphism and heteroplasmy in the mitochondrial DNA control region of threespine stickleback (Gasterosteus aculeatus)2004In: Behaviour: An International Journal of Behavioural Biology, ISSN 0005-7959, Vol. 141, no 11-12, p. 1357-1369Article in journal (Refereed)
    Abstract [en]

    Length polymorphism and heteroplasmy (multiple forms within a single individual) in the mitochondrial DNA (mtDNA) control region have been reported for several species of fish. In this report we demonstrate its existence in the threespine stickleback (Gasterosteus aculeatus). The repeat region, responsible for the length variation and heteroplasmy is located near the 5´ end of the control region and consists of slightly imperfect palindromic sequences. The repeat sequences vary in copy number from 1.5 to 16.5 and are capable of forming secondary structures. All individuals examined were heteroplasmic for 4 or more different copy number of repeats. Our results indicate that the repeats are a result of frequent competitive misalignment in the repeat region prior to replication and support the “illegitimate elongation model” as an explanation of the origin and maintenance of length heteroplasmy in the 5´ end of the control region.

  • 32.
    Jacobson, Henrik
    et al.
    Mälardalen University, Department of Public Technology.
    Forsberg, Åke
    Mälardalen University, Department of Public Technology.
    Odelström, Tommy
    Mälardalen University, Department of Public Technology.
    Dagvattenkvaliteten i anslutning till Hamnområdet i Västerås2006In: Vatten: Tidskrift för vattenvård, ISSN 0042-2886, Vol. 62, no 2, p. 149-159Article in journal (Other (popular science, discussion, etc.))
    Abstract [en]

    Dagvattenkvaliteten i hamnområden är ofta svår att definiera på grund av att hamnen ofta ligger inom industriområden med flera angränsande verksamheter och aktörer sammankopplade i samma avlopp och dagvattensystemet. Eftersom hamnen ligger närmast recipienten påverkas mätresultatet i hamnens provtagningspunkt av samtliga i avlopps- och dagvattensystemets tillförda föroreningar, vilket utgör svårigheter att få en tydlig bild av enbart hamnverksamhetens miljöpåverkan av vattnet. Bedömningsgrunder för vattenkvalitet i dagvatten och avloppsvatten är svårdefinierbara. De bedömningsgrunder som finns bygger på ett statistiskt material som utgår från olika provtagningar gjord i dag- och avloppsvatten system runt om i Sverige.

    Däremot i naturvatten finns goda underlag till vattenkvalitetsbedömningar i form av gränsvärden och normer vilka är vedertagna i litteraturen.

    I Västerås har hamnbolaget under några års tid haft hela ansvaret för mätning av förorenat vattnet i områdets dagvattensystem. Detta gäller även de föroreningar som inte härstammar från hamnens egen verksamhet, utan även från den omkringliggande. Juridiskt sett strider detta mot de allmänna hänsynsreglerna om att förorenaren betalar som beskrivs i miljöbalken. Kostnaderna har lagts på en enskild aktör för ett helt avlopps och dagvattensystem, där flera aktörer bidrar till miljöbelastningen. Detta har skett med förevändningen att hamnen är enskilt största verksamhet som bidrar med de största utsläppen av föroreningar till vattnet, vilket denna studie visar vara det motsatta förhållandet.

  • 33.
    Krustok, Ivo
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Odlare, Monica
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Truu, Marika
    University of Tartu, Estonia.
    Truu, Jaak
    University of Tartu, Estonia.
    Ligi, Teele
    University of Tartu, Estonia.
    Tiirik, Kertu
    University of Tartu, Estonia.
    Nehrenheim, Emma
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Effect of lake water on algal biomass and microbial community structure in municipal wastewater based lab-scale photobioreactors2015In: Applied Microbiology and Biotechnology, ISSN 0175-7598, E-ISSN 1432-0614, Vol. 99, no 21, p. 6537-6549Article in journal (Refereed)
    Abstract [en]

    Photobioreactors are a novel environmental technology that can produce biofuels with the simultaneous removal of nutrients and pollutants from wastewaters. The aim of this study was to evaluate the effect of the lake water addition to the production of algal biomass, and phylogenetic and functional structure of the algal and bacterial communities in the lab-scale bioreactors treating municipal wastewater.

    The lake water addition has significant benefit to the overall algal biomass growth and nutrient reduction in the reactors with wastewater and lake water (ratio 70/30 v/v). The metagenome based survey showed that the most abundant algal phylum in these reactors was Chlorophyta with Scenedesmus being the most prominent genus. The most abundant bacterial phyla were Proteobacteria and Bacteroidetes with most dominant families being Sphingobacteriaceae, Cytophagaceae, Flavobacteriaceae, Comamonadaceae, Planctomycetaceae, Nocardiaceae and Nostocaceae. These photobioreactors were also effective in reducing the overall amount of pathogens in wastewater compared to reactors with wastewater/tap water mixture. Functional analysis of the photobioreactor metagenomes revealed an increase in relative abundance genes related to photosynthesis, synthesis of vitamins important for auxotrophic algae, and decrease in virulence and nitrogen metabolism subsystems in lake water reactors.

  • 34.
    Larseriksdotter, Helén
    et al.
    Mälardalen University, Department of Biology and Chemical Engineering.
    Jansson, Östen
    Biacore AB, Sweden.
    Zhukov, Andrei
    Biacore AB, Sweden.
    Areskoug, Daphne
    Biacore AB, Sweden.
    Oscarsson, S
    Mälardalen University, Department of Biology and Chemical Engineering.
    Buijs, J
    Biacore AB, Sweden.
    Optimizing the surface plasmon resonance/mass spectrometry interface for functional proteomics applications2006In: Proteomics, ISSN 1615-9853, Vol. 6, no 8, p. 2355-2364Article in journal (Refereed)
    Abstract [en]

    A great challenge in functional or interaction proteomics is to map protein networks and establish a functional relationship between expressed proteins and their effects on cellular processes. These cellular processes can be studied by characterizing binding partners to a "bait" protein against a complex background of other molecules present in cells, tissues, or biological fluids. This so-called ligand fishing process can be performed by combining surface plasmon resonance biosensors with MS. This combination generates a unique and automated method to quantify and characterize biomolecular interactions, and identify the interaction partners. A general problem in chip-based affinity separation systems is the large surface-to-volume ratio of the fluidic system. Extreme care, therefore, is required to avoid nonspecific adsorption, resulting in losses of the target protein and carry-over during the affinity purification process, which may lead to unwanted signals in the final MS analysis and a reduction in sensitivity. In this study, carry-over of protein and low-molecular weight substances has been investigated systematically and cleaning strategies are presented. Furthermore, it is demonstrated that by the introduction of colloidal particles as a capturing and transporting agent, the recovery yield of the affinity-purified ligand could be improved nearly twofold.

  • 35.
    Lindenfors, Patrik
    et al.
    Stockholms universitet.
    Jansson, Fredrik
    Mälardalen University, School of Education, Culture and Communication.
    Sandberg, Mikael
    Stockholms universitet.
    The Cultural Evolution of Democracy: Saltational Changes in a Political Regime Landscape2011In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 6, no 11, p. e28270-Article in journal (Refereed)
    Abstract [en]

    Transitions to democracy are most often considered the outcome of historical modernization processes. Socio-economic changes, such as increases in per capita GNP, education levels, urbanization and communication, have traditionally been found to be correlates or 'requisites' of democratic reform. However, transition times and the number of reform steps have not been studied comprehensively. Here we show that historically, transitions to democracy have mainly occurred through rapid leaps rather than slow and incremental transition steps, with a median time from autocracy to democracy of 2.4 years, and overnight in the reverse direction. Our results show that autocracy and democracy have acted as peaks in an evolutionary landscape of possible modes of institutional arrangements. Only scarcely have there been slow incremental transitions. We discuss our results in relation to the application of phylogenetic comparative methods in cultural evolution and point out that the evolving unit in this system is the institutional arrangement, not the individual country which is instead better regarded as the 'host' for the political system.

  • 36.
    Lindenfors, Patrik
    et al.
    Stockholms universitet.
    Sandberg, Mikael
    Högskolan i Halmstad.
    Jansson, Fredrik
    Mälardalen University, School of Education, Culture and Communication.
    Demokratins evolution2012In: Gaudeamus, ISSN 0016-5247, no 1, p. 14-15Article in journal (Other (popular science, discussion, etc.))
  • 37. Morgan, T. J. H.
    et al.
    Rendell, L. E.
    Ehn, Micael
    Stockholms universitet, Centrum för evolutionär kulturforskning.
    Hoppitt, W.
    Laland, K. N.
    The evolutionary basis of human social learning2012In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 279, no 1729, p. 653-662Article in journal (Refereed)
    Abstract [en]

    Humans are characterized by an extreme dependence on culturally transmitted information. Such dependence requires the complex integration of social and asocial information to generate effective learning and decision making. Recent formal theory predicts that natural selection should favour adaptive learning strategies, but relevant empirical work is scarce and rarely examines multiple strategies or tasks. We tested nine hypotheses derived from theoretical models, running a series of experiments investigating factors affecting when and how humans use social information, and whether such behaviour is adaptive, across several computer-based tasks. The number of demonstrators, consensus among demonstrators, confidence of subjects, task difficulty, number of sessions, cost of asocial learning, subject performance and demonstrator performance all influenced subjects' use of social information, and did so adaptively. Our analysis provides strong support for the hypothesis that human social learning is regulated by adaptive learning rules.

  • 38.
    Norström Paananen, Marcus
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Boström, Magnus
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Ahlgren, Christian
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Power Lines - Wasteland or Biodiversity Hotspots?2008Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As a consequence of the intensification of various forms of human resource utilization rural Sweden has changed radically over the past 200 years from offering a varied and diverse landscape to a more monotonous, homogenised type of environment. This has led to fragmentation of habitats for many of the species occurring. Power line corridors might harbour habitats that resemble some of the now lost or fragmented habitats (e.g. grazed forest land and certain types of meadow), and could have important functions as refuge habitats and / or distribution corridors for these species.

    In a pitfall trap study in Köping and Strängnäs municipalities in Mälardalen, the occurrence and abundance of ground-living invertebrates were investigated in power line corridors, adjoining forest and pastures. Comparisons were made between these habitat types, and between positions within the power line corridor (central and distal parts) and the nearby forested area. The comparisons included analysis of number of species (or rather the number of taxa) and several biodiversity indexes, as well as analysis of the similarity of the occurrence of certain species and individual numbers by use of "similarity index". Separate tests were made in different taxonomic groups (e.g. all taxa, only within insects, only within spiders). The number of replicates allowed statistical testing of patterns in the number of taxa and biodiversity index.

    No significant differences were documented, neither between the different habitat types, nor between positions in the power line corridors and nearby forest. There was also no consistent (non-significant) pattern indicating that this would be the case. We suggest these results to indicate that power line corridors at least are not (significantly) poorer quality habitats than are forest or pasture land with regard to number of taxa and biodiversity. Number of taxa and biodiversity indices take no account of the species or taxa included in the analysis. Thus the same weight is assigned to an unwanted species (e.g. an invasive pest species or parasite) as to a red-listed, highly valued species. Similarity index takes more heed to the species involved. Although similarity indices do not consider the exact identity of involved species (or their possible value or desirability), a high index value indicates that the same species occur in the compared habitats. In this study, where an index that takes into account the abundance of species was used, a high similarity index value also indicates that the numbers of individuals are similar.

    Overall, the results showed high similarity between habitat types. This would suggest that, to a large extent, power lines, forest and pasture land had the same composition of taxa, and that the taxa had similar abundances. Power lines and forest seemed to exhibit particularly high similarities, whereas the similarity between power lines and pasture land was less pronounced. Thus, this study indicates, in contrast to several previous suggestions, that power line corridors do not seem to be low quality habitats. We also suggest that power line corridors with well designed management routines could play an important role creating edges and habitats resembling meadow or low intensity grazed pasture land.

  • 39.
    Oscarsson, Sven
    Mälardalen University, Department of Biology and Chemical Engineering.
    Influence of salts on protein interactions at interfaces of amphiphilic polymers and adsorbents1995In: J Chromatogr B Biomed Appl, ISSN 0378-4347, Vol. 666, no 1, p. 21-31Article in journal (Refereed)
    Abstract [en]

    The protein-binding capacity of two different amphiphilic adsorbents was investigated to determine the effect of solvent additives on the binding of proteins in hydrophobic-interaction chromatography. There was no simple correlation between binding capacity and the lyotropic series such as those suggested by the two different theories proposed by Arakawa and Narhi and Melander and Horvath. Proteins are known to be dynamic flexible objects which continuously undergo changes in conformation and which may well be influenced by chaotropic salts. Are conformational changes of proteins at interfaces an important parameter involved in protein interactions with amphiphilic polymers and adsorbents? In an attempt to answer this question, the reactivity of the thiol group in human serum albumin (HSA) toward N-ethyl-3-(2-pyridyldisulfanyl)propionamide dextran was used as a model system to evaluate its correlation with the lyotropic series. The results indicate that the thiol-disulfide exchange reaction at interfaces of amphiphilic polymers is influenced by the type of salt used.

  • 40.
    Paulsson, Henrik
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Spridningsmönster och potentiella spridningsytor hos invasionsarten stor bockrot (Pimpinella major) i Tullgarns naturvårdsområde: ett framtida problem för områdets diversitet?2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    An organism that is transferred from one place to another, causing major problems to the native species is termed invasive. Its natural dispersal across barriers may have been prevented but as man has turned able to rapidly travel all over the world organisms are brought to sites where they were never before observed. Adding the increasing global warming organisms may find it necessary to move around even further. This might cause major disturbance to the biological diversity, and hybridization and homogenization is one of many scenarios that could disturb the native diversity. In Sweden more that 2/3 of all alien plant species have been introduced to disturbed areas and the major introduction mechanism is gardening. The object of study in this presentation, Pimpinella major (Apiaceae) was introduced in Sweden alongside garden grasses during the 19th century but has so far spread only marginally from the areas of introduction. The aim of the study was to quantify the appearance of Pimpinella major in different types of vegetation apart from road verges, where it has been noted systematically for over a decade. The investigation area covers most of the Tullgarn nature reserve. The result shows an astonishing tendency of P. major to remain growing only along the roads in the area. The very few findings besides next to roads are from deciduous and coniferous forests and fields. It seems that Pimpinella major almost without exception prefers heavily disturbed areas and access to large amounts of nitrogen fertilizer from exhaust fumes

  • 41.
    Petersson, Johanna
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Sex- och samlevnadsundervisning i grundskolans senare år2010Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I den samhälle som ungdomar idag lever i finns sexualiteten ständigt närvarande genom olika media. Undervisning i sexualkunskap har funnits i skolan sedan början av 1900-talet och varit obligatorisk sedan 1955. Idag benämns sex och samlevnad som ett ämnesövergripande arbetsområde i läroplanen, och anges vara en del av rektors ansvar.

    Syftet med denna undersökning var att studera sex- och samlevnads-undervisning på grundskolorna i en kommun i Mellansverige. Undervisningens upplägg och innehåll studerades och jämfördes mellan skolorna och med tidigare forskning. Undersökningen genomfördes i form av ett frågeformulär som skickades ut till de arbetslag som valde att delta. Resultatet visade att sex- och samlevnads-undervisning är ett arbetsområde som främst bedrivs inom biologiämnet och genomförs under ett antal veckor i årskurs åtta. Rektors ansvar att ge arbetet en ämnesövergripande karaktär framgår inte på de deltagande skolorna. Innehålls-mässigt inkluderar undervisningen vanligtvis pubertet, fortplantning, onani, sexuellt överförbara infektioner, preventivmedel, relationer och kärlek.

    Slutsatserna från undersökningen var att sex- och samlevnadsundervisningen behöver bli mer ämnesövergripande och återkomma i fler årskurser, fler män behöver leda undervisning inom området, kompetens-utveckling behöver erbjudas personalen, undervisningsmetoderna, samt kontakten mellan hem och skola inom arbetsområdet, behöver utvecklas.

  • 42.
    Ribé, Veronica
    et al.
    Mälardalen University, School of Business, Society and Engineering.
    Aulenius, Elisabet
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Nehrenheim, Emma
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Martell, Ulrika
    Structor Environmental Engineering.
    Odlare, Monica
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Applying the Triad method in a risk assessment of a former surface treatment and metal industry site2012In: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 207, no SI, p. 15-20Article in journal (Refereed)
    Abstract [en]

    With a greater focus on soil protection in the EU, the need for ecological risk assessment tools for cost-effective characterization of site contamination is increasing. One of the challenges in assessing the risk of soil contaminants is to accurately account for changes in mobility of contaminants over time, as a result of ageing. Improved tools for measuring the bioavailable and mobile fraction of contaminants is therefore highly desirable. In this study the Triad method was used to perform a risk characterization of a former surface treatment and metal industry in Eskilstuna, Sweden. The risk assessment confirmed the environmental risk of the most heavily contaminated sample and showed that the toxic effect was most likely caused by high metal concentrations. The assessment of the two soil samples with low to moderate metal contamination levels was more complex, as there was a higher deviation between the results from the three lines of evidence; chemistry, (eco)toxicology and ecology. For the slightly less contaminated sample of the two, a weighting of the results from the ecotoxicological LoE would be recommended in order to accurately determine the risk of the metal contamination at the sampling site as the toxic effect detected in the Microtox® test and Ostracodtoxkit™ test was more likely to be due to oil contamination. The soil sample with higher total metal concentrations requires further ecotoxicological testing, as the integrated risk value indicated an environmental risk from metal contamination. The applied methodology, the Triad method, is considered appropriate for conducting improved environmental risk assessments in order to achieve sustainable remediation processes.

  • 43.
    Ribé, Veronica
    et al.
    Mälardalen University, School of Business, Society and Engineering.
    Nehrenheim, Emma
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Odlare, Monica
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Berglind, Rune
    FOI CBRN Defence and Security, Swedish Defence Research Agency.
    Forsberg, Åke
    Mälardalen University, School of Sustainable Development of Society and Technology.
    EVALUATION OF THE PERFORMANCE AND SAFETY OF A PINE BARK FILTER FOR LANDFILL LEACHATE AND STORMWATER TREATMENT: TOXICITY TESTING AND CHEMICAL ANALYSIS2011In: Sardinia 2011 Symposium, Thirteenth International Waste Management and Landfill Symposium, Proceedings / [ed] R. Cossu, CISA Publisher , 2011, p. 1143-Conference paper (Refereed)
    Abstract [en]

    The industrial by-product pine bark has been used successfully as a low-cost sorbent for removing heavy metals from wastewaters such as stormwaters and landfill leachates. Although the water treatment efficiency of pine bark is high, one reported drawback with using the filter material for water treatment is the potential leaching of organic compounds, e.g. tannines and other polyphenols. This phenomenon is likely to be particularly pronounced during the initial start-up phase of filtration with unused pine bark. The results from preliminary serial leaching tests with the filter material, has shown that the toxicity of the pine bark leachates to Daphnia magna (48 hr) decreases after each successive round of leaching. The aim of this study was to further investigate the leaching properties and stability of pine bark filter. In this study, parallel serial batch leaching experiments were performed with either doubly deionised or U.S. EPA moderately hard reconstituted water as leachant to determine the duration and extent of the initial desorption of organic material, analysed as DOC (Dissolved Organic Carbon), from the filter material. To further investigate the changes in toxicity of the pine bark leachates from each successive round of leaching, a more extensive toxicity assessment was performed with an aquatic ecotoxicity test battery consisting of an acute luminescent bacteria test (ROTAS) and a genotoxicity test (the Umu assay using Salmonella typhimurium TA1535/pSK1002). 

  • 44.
    Richardsson, Kristin
    Mälardalen University, School of Business, Society and Engineering.
    Miljöberikning av vithandad gibbonapa, Hylobates lar, Parken Zoo, Eskilstuna2013Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
  • 45.
    Rioldi, Emmanuela
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Innovative environmental enrichment method for Pallas cat (Felis manul)2010Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Due to the expansion of the human population we are an increasing threat to all wild animals. They are driven to exist in smaller areas and in the worst case scenario extinction. Zoos are being encouraged to improve the animal’s physical and social surroundings. Environmental enrichment is a term used for such improvements. In this behavioural study, the enrichment introduced to two Pallas cats (Felis manul) at Parken Zoo in Eskilstuna, Sweden, consisted of a fishing rod and a clothes peg with a dead mouse or chick attached. The intention was to see if the feeding enrichment could increase activity levels and how the cats were using their enclosure. The enclosure was divided into seven zones which have a varying degree of opportunities for the animals to climb, hide and rest above ground level. The environmental enrichment effects on the Pallas cats´ behaviour, activity levels and use of the enclosure were measured and recorded using instantaneous scan sampling, and the mean value was calculated for each individual. The behavioural and enclosure results proved that enrichment benefits the cats activity levels. The behaviours that showed a variation when presented with enrichment were: walking, climbing, grooming, aggressive behaviour, out of sight behaviour, crouching position, sitting and standing still.  The results showed that the cats preferred the zones in the enclosure that offered a larger view of the nearby enclosures. This study shows that providing captive felids with inexpensive, easy to administer enrichment objects can have profound effects on activity behaviours and their enclosure.

     

  • 46.
    Rosengren, Agneta
    et al.
    Mälardalen University.
    Oscarsson, Sven O.
    Mälardalen University.
    The influence of plasma proteins on bone cell adhesion2008In: Cellular Response to Biomaterials, Elsevier Ltd. , 2008, p. 538-559Chapter in book (Other academic)
    Abstract [en]

    This chapter gives an introduction to the tools and the background knowledge for further studies of cell-substrate interactions. A cell adhesion test is presented by which it is possible to study the functional behavior of specific proteins after adsorption. The test used model surfaces, cycloheximide treatment, fluorescence microscopy and divalent cations (Mg2+/Ca2+) for cell quantification, cell morphological studies and monitoring of specific/non-specific cell-substrate interactions.Four plasma proteins, ceruloplasmin, prothrombin, 2-HS-glycoprotein and 1-antichymotrypsin, have been investigated. The goal was to monitor their orientation and (if possible) conformational changes after adsorption and to study their influence on bone cell adhesion as a result of the adsorption process.The study was performed on ultraflat model surfaces (silicon wafers with a natural layer of silicon oxide/silica) to be able to characterize the adsorbed proteins with atomic force microscopy (AFM) and ellipsometry, and to single out the protein-induced effect on the cell activity by reducing interfering surface properties (e.g., topography, variations in surface chemistry). The dimensions of the adsorbed proteins on silicon wafers were measured with the AFM and the values were compared with available X-ray data. The molecules appeared to be oriented with their long axis parallel to the surface or, as in the case of ceruloplasmin, with one of its larger sides towards the surface.

  • 47.
    Rönnegård, Lars
    et al.
    Uppsala University, Sweden .
    Mishchenko, Kateryna
    Mälardalen University, Department of Mathematics and Physics. Uppsala University, Sweden .
    Holmgren, Sverker
    Uppsala University, Sweden .
    Carlborg, Örjan
    Uppsala University, Sweden .
    Increasing the Efficiency of Variance Component Quantitative Trait Loci Analysis by Using Reduced-Rank Identity-by-Descent Matrices2007In: Genetics, ISSN 0016-6731, Vol. 176, no 3, p. 1935-1938Article in journal (Refereed)
    Abstract [en]

    Recent technological development in genetics has made large-scale marker genotyping fast and practicable, facilitating studies for detection of QTL in large general pedigrees. We developed a method that speeds up restricted maximum-likelihood (REML) algorithms for QTL analysis bysimplifying the inversion of the variance-covariance matrix of the trait vector. The method was tested in an experimental chicken pedigree including 767 phenotyped individuals and 14 genotyped markers on chicken chromosome 1. The computation time in a chromosome scan covering 475 cM was reduced by 43% when the analysis was based on linkage only and by 72% when linkage disequilibrium information was included. The relative advantage of using our method increases with pedigree size, marker density, and linkage disequilibrium, indicating even greater improvements in the future. 

  • 48.
    Salmijärvi, Sari
    Mälardalen University, Department of Biology and Chemical Engineering. Mälardalen University, School of Sustainable Development of Society and Technology.
    Genetisk artbestämning och karaktärisering av Trypanosoma theileri2008Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
  • 49.
    Soderbaum, Peter
    Mälardalen University, School of Sustainable Development of Society and Technology.
    The Plundered Planet, Why We Must - and How We Can - Manage Nature for Global Prosperity2011In: Ecological Economics, ISSN 0921-8009, E-ISSN 1873-6106, Vol. 70, no 6, p. 1240-1240Article, book review (Other academic)
  • 50.
    Stone, L.
    et al.
    Yigal Allon Kinneret Limnological Laboratory, Israel Oceanographic & Limnological Research, Israel.
    Bonner, R.
    Griffith University, Queensland, Australia .
    Berman, T.
    Yigal Allon Kinneret Limnological Laboratory, Israel Oceanographic & Limnological Research, Israel.
    Barry, S.
    Griffith University, Queensland, Australia .
    Weeks, S.
    Griffith University, Queensland, Australia .
    Lake Kinneret: A seasonal model for carbon flux through planktonic biota1993In: Limnology and Oceanography, ISSN 0024-3590, Vol. 38, no 8, p. 1680-1695Article in journal (Refereed)
12 1 - 50 of 58
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