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Sökning: FÖRF:(Helena Andersson) > Doktorsavhandling

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1.
  • Andersson, Helena, 1961- (författare)
  • Möten där vi blir sedda : en studie om elevers engagemang i skolan
  • 2017
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • AbstractThis thesis concerns students’ engagement with school. In Sweden there are as many as 17,5 % of the students, who after year nine do not get the grades in order to be admitted to the national program at the upper secondary school. In this thesis, Students’ experiences are focused in order to understand engagement with school. The study is grounded in a socio cultural perspective on learning where learning is considered to originate from social actions, as well as theoretical perspectives on engagement. In the thesis learning is seen as development not as a process within the child but rather as development that takes place when the child participates in practices within their cultural community and in relations with others. Learning is looked upon as a perspective where the context of our lived experience of participation in the world is important.  Learning should be seen as social participation. This kind of participation does not only shape what we do but also who we are and who we can become. In this thesis the concept of engagement is considered as both the wanting to do something, and what the student actual do, the agency of the student.  An exploratory sequential mixed method has been used in the data collection, mainly with a student perspective. This means that both quantitative and qualitative methods of collecting and analyzing data has been used to be able to answer the research questions. The overall aim of the thesis is to contribute with knowledge about students’ engagement in school by identifying aspects that influence the engagement.The thesis consists of three different studies. One quantitative study, where 1298 student participated in a survey concerning student engagement with school, which was followed by two qualitative studies, where the descriptive analysis was broadened with interviews, one with students and teachers in two different classes and one with students from eight different schools. Apart from that, students have written reflections on how they experience their learning environments in school.  The discussion concerns whether students in year seven are engaged with their school, both according to the psychological and according to the cognitive engagement. The discussion also concerns what aspects of engagement students and their teachers in two highly engaged classes have experienced. In the study students with different socioeconomically and cultural backgrounds take part. The concepts of students’ participation and influence in their schoolwork is also discussed.
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2.
  • Andersson, Helena (författare)
  • Möten där vi blir sedda : en studie om elevers engagemang i skolan
  • 2017
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • This thesis concerns students’ engagement with school. In Sweden there are as many as 17,5 % of the students, who after year nine do not get the grades in order to be admitted to the national program at the upper secondary school. In this thesis, Students’ experiences are focused in order to understand engagement with school. The study is grounded in a socio cultural perspective on learning where learning is considered to originate from social actions, as well as theoretical perspectives on engagement. In the thesis learning is seen as development not as a process within the child but rather as development that takes place when the child participates in practices within their cultural community and in relations with others. Learning is looked upon as a perspective where the context of our lived experience of participation in the world is important. Learning should be seen as social participation. This kind of participation does not only shape what we do but also who we are and who we can become. In this thesis the concept of engagement is considered as both the wanting to do something, and what the student actual do, the agency of the student. An exploratory sequential mixed method has been used in the data collection, mainly with a student perspective. This means that both quantitative and qualitative methods of collecting and analyzing data has been used to be able to answer the research questions. The overall aim of the thesis is to contribute with knowledge about students’ engagement in school by identifying aspects that influence the engagement. The thesis consists of three different studies. One quantitative study, where 1298 student participated in a survey concerning student engagement with school, which was followed by two qualitative studies, where the descriptive analysis was broadened with interviews, one with students and teachers in two different classes and one with students from eight different schools. Apart from that, students have written reflections on how they experience their learning environments in school. The discussion concerns whether students in year seven are engaged with their school, both according to the psychological and according to the cognitive engagement. The discussion also concerns what aspects of engagement students and their teachers in two highly engaged classes have experienced. In the study students with different socioeconomically and cultural backgrounds take part. The concepts of students’ participation and influence in their schoolwork is also discussed.
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3.
  • Andersson, Helena, 1976- (författare)
  • Gotländska stenåldersstudier : Människor och djur, platser och landskap
  • 2016
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • This thesis deals mainly with the Middle Neolithic period (ca. 3200-2300 BC) on the island of Gotland in the Baltic Sea. The aim is to deepen the understanding of how the islanders related to their surroundings, to the landscape, to places, to objects, to animals and to humans, both living and dead. The archaeological material is studied downwards and up with a focus on practices, especially the handling and deposition of materials and objects in graves, within sites and in the landscape. The study is comparative and the Middle Neolithic is described in relation to the Early Neolithic and the Mesolithic period on the island.From a long term perspective the island is presented as a region where strong continuity can be identified, regarding both way of life and economy. In contrast, substantial changes did occur through time regarding the islander’s conceptions of the world and of social relations. This in turn affected the way they looked upon the landscape, different sites and animals, as well as other human beings. During the Mesolithic, the islanders first saw it as possible to create their world, their micro-cosmos, wherever they were, and they saw themselves as living in symbiosis with seals. With time, though, they started to relate, to connect and to identify themselves with the island, its landscape and its material, with axe sites and a growing group identity as results. The growing group identity culminated during the Early Neolithic with a dualistic conception of the world and with ritualised depositions in border zones.The Middle Neolithic is presented as a period when earlier boundaries were dissolved. This concerned, for example, boundaries towards the world around the islanders and they were no longer keeping themselves to their own sphere. At the same time individuals became socially important. It became accepted and also vital to give expression to personal identity, which was done through objects, materials and animals. Despite this, group identity continued to be an important part in their lives. This is most evident through the specific Pitted Ware sites, where the dead were also treated and buried. These places were sites for ritual and social practices, situated in visible, central and easy accessible locations, like gates in and out of the islands’ different areas. The dead were very important for the islanders. In the beginning of MN B they started to adopt aspects from the Battle Axe culture, but they never embraced Battle Axe grave customs. Instead they held on to the Pitted Ware way of dealing with the dead and buried, and to the Pitted Ware sites, through the whole period, with large burial grounds as a result.
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4.
  • Andersson, Helena (författare)
  • The role of subsoil properties for phosphorus leaching in agricultural soils
  • 2016
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Phosphorus (P) leaching from agricultural land is a large contributor to eutrophication of many surface waters and the Baltic Sea. Better knowledge of P sorption and release in the subsoil could enable the development of effective mitigation strategies for P leaching. This thesis examined the impact of soil properties on P leaching from four Swedish agricultural soils (two clays, two sands), using intact soil columns extracted with (length 1.05 m) and without (length 0.77 m) topsoil. The role of the subsoil as a source or sink for P leaching was also investigated, and placement of quicklime (CaO) on top of the subsoil as a mitigation strategy for P leaching was evaluated. Leaching of dissolved reactive P (DRP) from subsoil lysimeters was 94% of that from full-length lysimeters in one of the clay soils, and 70% in the other. The higher contribution of the former clay subsoil was probably due to high P content deeper in the soil. Leaching of DRP was low from full-length and subsoil lysimeters (0.12 and 0.08 kg ha-1 yr-1, respectively) in one of the sandy soils, despite high topsoil P content, due to high P sorption capacity and low degree of P saturation in the subsoil. However, leaching of DRP was very high from full-length and subsoil lysimeters (3.33 and 3.29 kg ha-1 yr-1, respectively) from the other sandy soil with moderate topsoil P content, due to high P content and low P sorption capacity in the subsoil. These results indicate that the subsoil can function as both a source and sink for P leaching. Phosphorus leaching increased with increasing P content and DPS in subsoil and decreasing P sorption capacity in topsoil and subsoil, indicating that these parameters could be used for P leaching risk assessments. However, on soils with preferential flow in the subsoil, P leaching may be high despite high subsoil P sorption capacity. Hence, both chemical and physical properties of topsoil and subsoil must be considered in implementation of appropriate, cost-effective mitigation strategies for P loss reductions. Application of lime on top of the subsoil significantly reduced leaching of particulate P (PP) in both clay subsoils by 49 and 51%, respectively, compared with unlimed controls. This suggests that subsoil liming might be an appropriate method to reduce P leaching from clay soils.
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5.
  • Andersson, Helena M., 1973- (författare)
  • The physiological impact of soccer on elite female players and the effects of active recovery training
  • 2010
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Female soccer is becoming more popular and professional in the world. There are, however, limited scientific data available on how elite female players respond to physical stress during soccer games. An effective recovery strategy following a game is important, because there are few recovery days between the games in international tournaments. The present thesis, which was designed to mirror a competitive situation, aimed to investigate changes in several physiological systems occurring in female elite players in response to two soccer games. It also aimed to investigate the effects of active recovery training on the recovery of several physiological systems. METHODS: Two elite female soccer teams played two 90-min games separated by 72 h active or passive recovery. The active recovery training (cycling at 60% HRpeak, resistance training at <50% 1RM) lasted one hour and was performed 22 and 46 h after the first game. Countermovement jump (CMJ), 20-m sprint time and isokinetic knee strength were measured before, immediately, 5, 21, 45, 51, and 69 h after the first game, and immediately after the second game. The physical stress markers (CK, urea), oxidative stress markers (e.g., GSSG, lipid peroxidation), endogenous (e.g., UA, thiols) and dietary antioxidants (e.g., tocopherols, carotenoids) and a large battery of cytokines (e.g., IL-6, TNF-α) were analysed in blood. RESULTS: No significant differences were observed in the performance parameters, oxidative stress and antioxidant levels or inflammatory response between the active and passive recovery groups. Sprint and isokinetic knee strength were reduced by the same extent after both games. CMJ decreased after the first game and remained reduced throughout the study period. Blood physical stress markers, GSSG and endogenous antioxidants increased with similar amplitude after both games together with unchanged lipid peroxidation. The dietary antioxidants showed either a rapid and persistent change (e.g., tocopherols) or a delayed rise (carotenoids) after the first game. A transient increase occurred in several pro- (e.g., IL-12, TNF-a, MCP-1), anti-inflammatory (e.g., IL-4, IL-10, INF-a) and mixed (IL-6) cytokines after the first game. Fewer cytokines increased in response to the second game. CONCLUSION: Two repeated elite female soccer games separated by 72 h induced similar acute changes in several physiological parameters. After the first game, differences in the recovery pattern of the neuromuscular parameters occurred. In particular, the slow recovery of CMJ indicates that special attention should be devoted to the training of explosive force. Furthermore, the recruitment of antioxidants in response to the transient increase in GSSG resulted in the maintenance of the redox-balance in female players. Similarly, a strong and balanced pro- and anti-inflammatory cytokine response occurred after one single female soccer game. The consequences of the dampened cytokine response during repeated soccer games are, however, unknown. In general, the majority of the parameters had recovered prior to the second game and the physiological alterations induced by the first game did not affect the performance of players in the second game. Finally, active recovery training conducted after a soccer game does not accelerate the recovery time for neuromuscular, oxidative stress, antioxidant and inflammatory responses in elite female players.
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6.
  • Andersson, Helena, 1969- (författare)
  • Interkulturell kommunikation på ett svenskt sjukhus : Fallstudier av andraspråkstalare i arbetslivet
  • 2009
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • This dissertation investigates the communication of immigrants employed at a Swedish hospital. The overall aim is to find factors that have a positive effect on their integration into the workplace. The data comprise observations, field notes and approximately 80 hours of audio recordings with five second language speakers made during their everyday activities at work. Since entire workdays have been recorded the data include both professional and social interaction, such as meetings, interaction with patients and small talk between colleagues. In preparation for the case studies a number of interviews were conducted at the hospital and they gave valuable knowledge about the hospital routines and how second language speakers experience their communicative situation.The five participants in the case studies are one male cleaner from Tanzania, two female nurses, one from Iran and one from Lebanon, and two female physicians, one from Hungary and one from Lithuania. The number of years spent in Sweden varies from 4 to 18.The analyses focus on communication strategies, humor and medical case rounds. The results show that lack of language skills is not a hindrance since the participants make use of different strategies to solve language problems. The dissertation also shows that, despite the difficulties and risks involved in the use of humor, the participants do so as a way of showing collegiality. The analysis of case rounds show that the participants are treated as equal interlocutors and contribute as much to the conversation as the first language speakers do. The results indicate, with a few exceptions, successful integration of the participants.Finally, the dissertation argues that a multicultural and multilingual staff is a positive feature since their skills in other languages can be used in ways that both save time and are of economic benefit to the employer. It also argues that Swedish teaching should focus more on interactional skills, for example so that the second language speakers are better prepared to face the communicative challenges they encounter in a workplace.
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7.
  • Andersson, Helena, 1966 (författare)
  • Crosslinking of Polymers. Molecular Structure and Properties of Sol and Network
  • 2004
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Crosslinking is a well-known procedure for improving a variety of features of polymers, particularly the dimension stability at elevated temperatures. Crosslinking implies the formation of a network, the gel, but there is always a certain portion of the material, the sol, that remains non-crosslinked within the network. Both fractions contribute to the properties of the crosslinked polymer, and the relative importance of the respective fraction depends on the type of polymer and the field of application. In this thesis, the significance of the molecular structure and property of a sol was illustrated by investigating the ability of crosslinked silicone elastomers to contaminate nearby structures, while analyses of the molecular structure of crosslinked polyethylene elucidated the behaviour of the network. The silicone study showed that the non-crosslinked fraction of a cured silicone elastomer consists mainly of non-volatile, low molecular weight siloxanes with a potential capacity of causing silicone contamination through migration. Gel-content determinations together with molecular weight determinations of the sol clearly showed that the most effective way to minimise migration is to remove the low molecular weight fraction prior to crosslinking. Thermal analyses demonstrated the pronounced temperature sensitivity of the crosslinking process, something which must be considered, as a too low temperature could lead to unnecessary low gel-contents, whereas an elevated temperature can be used as a tool to increase the final curing level. Analyses of crosslinked polyethylene demonstrated an extensive impact of the molecular weight on the gel-content formed upon crosslinking. Bimodal polyethylene, which always contains a substantial amount of low molecular weight chains, can thereby be prevented from developing high gel-contents upon crosslinking. A polymer network is to a large extent affected by the presence of long chain branches on the polymer chain. The amount and length of the branches influence the network performance mainly by affecting disentanglement of the branches. Coil volume and intramolecular crosslinking are other factors that are governed by the presence of long chain branches.
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8.
  • Andersson, Helena (författare)
  • Heavy metal neurotoxicity : on trimethyltin-, methylmercury- and cadmium-induced disturbances of neurotransmitter systems and neurotrophins
  • 1996
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Organic and inorganic metal compounds produced by human activities often reach the environment where they are associated with a plethora of potential health hazards. Of particular concern is the risk for CNS disturbances during development or in the adult. While considerable documentation exists concerning lead compounds, methodology needs to be developed to better understand the mechanisms of actions of many other heavy metal compounds. The present work studies the effects of tin, mercury and cadmium compounds inthe developing and adult rat. Trimethyltin (TMT) was chosen as a model organic metal compound with a specific neurotoxic profile in adult rats. Its actions were characterized using histological, histochemical, in situ hybridization, receptor binding and biochemical methods. A single injection causes neurodegenerative changes in the limbic system including a severe transient gliosis, neuronal degeneration, selective losses of NMDA and kainate receptors, an early transient decrease of BDNF followed by an up-regulation of BDNF and the immediate-early gene c-fos and hsp70 concomitant with a decrease in the BDNF trkB receptor mRNA. Astrocytes also show increased GABA immunoreactivity and an increase of the glial glutamate transporter mRNA, perhaps reflecting enhanced glial glutamate uptake. TMT also caused decreases of serotonin and noradrenalin levels in several brain regions while dopamine appeared not to be affected. Reduced levels of 5-HT were paralleled by reduced 5-HT nerve terminal densities in hippocampus and cortex. Attempting to block and/or counteract TMT toxicity, it was found that the non-NMDA antagonist DNQX was able to protect selected animals, and that PBN, a spin-trapping agent, offered partial protection, while the NMDA antagonist MK-801 and the GABA function enhancer chlormethiazole were without effects. Subtoxic doses of methylmercury (MeHg) caused specific decreases of hippocampal BDNF mRNA levels within hours, recovering after three days. The related neurotrophin NT-3 and trkB did not show mRNA changes. C-fos mRNA increased in a specific hippocampal cell population and in cerebral cortex and cerebellum even after very low doses of MeHg. The changes of BDNF mRNA expression were unlike those caused by many other CNS perturbations in which BDNF is up-regulated, and were not associated with major neuronal or glial damage at the chosen doses. Finally, long-term low-level exposure to mercury and cadmium during development was studied. MeHg exposure via the dams and the diet leading to brain concentrations of <1.5 mg Hg/kg caused no general toxic effects in neurons and no changes of GFAP-immunoreactive astrocytes. However, significant changes of cerebellar noradrenaline were found, underlining the importance of detailed and multifaceted biochemical and morphological analysis to detect possible negative effects of long-term low dosage exposure. Exposure to 5 ppm cadmium chloride in the drinking water during development led to significant changes of serotonin and noradrenalin levels in the cerebral cortex. BDNF mRNA was increased in cerebral cortex, while trkB mRNA was decreased in hippo-campus. Hence, chronic exposure to very low levels of cadmium chloride during development led to complex neurochemical disturbances of neurotransmitters as well as neurotrophins. It is concluded that morphological and biochemical analyses of brain tissue using markers of neurons and glial cells including transmitter systems, neurotrophic systems and immediate-early genes, together constitute a sensitive battery of techniques able to detect brain disturbances caused by very low level exposure of animals to heavy metals in cases where the use of a single technique is likely to miss the neurotoxic damage. Applying these and similar methods to rodents constitutes a general system capable of generating early warnings about the potential neurotoxic hazards of xenobiotics.
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