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The brain undergoes structural changes in response to new experiences like learning a new skill. Skilled motor movements depend greatly on the primary motor cortex for their execution. Recent studies describe rat strain differences in motor performance related to differential synaptic efficacy in the motor cortex of rats. Previous studies identified differences in motor performance related to differential dendritic morphology and strain related differences in synaptic function in the motor cortex. Strain differences are one way of investigating anatomical organization and behaviour of the motor system. The object of this research was to examine strain related differences in dendritic morphology in layer II / III pyramidal cells of the forelimb area of the sensory motor cortex in both Long-Evans and Fischer 344 rats after reach training. This research also examined whether changes in reaching behaviour could be attributed to changes in dendritic morphology. Rats were trained once a day for 30 days to reach for a food pellet through a slot in a reaching box. Pyramidal cells in the motor sensory forelimb (MSF) cortex were stained with the Golgi Cox method. Subsequent analysis of Sholl and branch order data of cell drawings determined that there were no significant differences in any measure of dendritic length or dendritic length at branch order 3, 4, 5 of pyramidal cells in layer II/III of the MSF cortex between the Long Evans and Fischer 344 rat strain. The only significant strain related difference was that the Fischer 344 strain exhibited fewer reaches for each food pellet obtained, demonstrating greater reaching proficiency than similarly trained Long-Evans rats. These findings suggest that further research examining strain comparisons is required to understand the neural mechanisms underlying the differences in motor behaviour observed in these rat strains.

Cannabis är den mest använda drogen i världen och attityderna gentemot den blir allt mer liberala. Då många syntetiskt framställda cannabinoider ständigt dyker upp på marknaden visar studier på olika resultat angående utbredningen av drogen. Det är personer i de yngre åldrarna som i störst utsträckning använder cannabis. I dagens samhälle ställs det allt mer krav på unga vuxna, inte minst när det gäller att skaffa sig en utbildning. Syftet med denna studie var därför att undersöka om det fanns något samband mellan användningen av cannabis och upplevelser av studiesituationen bland studenter vid Linköpings universitet.Studiens teoretiska utgångspunkt utgjordes av Robert K. Mertons strainteori där fokus låg på huruvida studenterna upplevde sig ha förutsättningar och medel att uppnå sitt mål; att klara av en utbildning. Populationen för studien var alla studenter som var registrerade på ett program. En totalundersökning gjordes av de studenter som våren 2014 studerade på ett program i termin fyra. Det empiriska materialet samlades in via en onlineenkät som besvarades av 1 481 respondenter.Resultatet visade att 36,8 % av respondenterna någon gång hade testat cannabis, männen var signifikant överrepresenterade. De flesta hade testat cannabis första gången då de studerade på gymnasiet. Respondenterna var över lag nöjda med sin studiesituation. Det var inte möjligt att se något samband mellan användningen av cannabis och upplevelser av studiesituationen som helhet.

The brain undergoes structural changes in response to new experiences like learning a new skill. Skilled motor movements depend greatly on the primary motor cortex for their execution. Recent studies describe rat strain differences in motor performance related to differential synaptic efficacy in the motor cortex of rats. Previous studies identified differences in motor performance related to differential dendritic morphology and strain related differences in synaptic function in the motor cortex. Strain differences are one way of investigating anatomical organization and behaviour of the motor system. The object of this research was to examine strain related differences in dendritic morphology in layer II / III pyramidal cells of the forelimb area of the sensory motor cortex in both Long-Evans and Fischer 344 rats after reach training. This research also examined whether changes in reaching behaviour could be attributed to changes in dendritic morphology. Rats were trained once a day for 30 days to reach for a food pellet through a slot in a reaching box. Pyramidal cells in the motor sensory forelimb (MSF) cortex were stained with the Golgi Cox method. Subsequent analysis of Sholl and branch order data of cell drawings determined that there were no significant differences in any measure of dendritic length or dendritic length at branch order 3, 4, 5 of pyramidal cells in layer II/III of the MSF cortex between the Long Evans and Fischer 344 rat strain. The only significant strain related difference was that the Fischer 344 strain exhibited fewer reaches for each food pellet obtained, demonstrating greater reaching proficiency than similarly trained Long-Evans rats. These findings suggest that further research examining strain comparisons is required to understand the neural mechanisms underlying the differences in motor behaviour observed in these rat strains.

This thesis focuses on the high strain rate behavior of Maraging steel 300, High Hardness Armor (HHA) and Aluminum 5083 – H131 Alloy. These materials are used by the Department of National Defense (DND) of Canada as armor plate materials in military applications. The aim of the research is to investigate the dynamic shear-strain response of these armor materials at high strain rate loading to study the occurrence of Adiabatic Shear Bands and the subsequent failure. The effects of impact momentum and strain rates on the dynamic stress-strain curve and on the adiabatic shear failure of these armor materials under impact and torsion loading need to be investigated to evaluate their capability to withstand military conditions.

The objective of this thesis is to develop a nondestructive evaluation method that could accurately locate and size damage in structures. The method is to be based on pre-damage and post-damage strain energies of beam and column elements. The method should apply to 1-D as well as 2-D and 3-D structures with single or multiple damage locations. To achieve the objectives listed above, the following four tasks are addressed: (1) the development of the theoretical foundations of the nondestructive evaluation theory; (2) the validation of the accuracy of the theory using exact structural deformational data generated from the static analysis of F. E. models in SAP2000; (3) the validation of the practical feasibility of the theory using approximated structural deformational data generated from the modal analyses of F.E. models in SAP2000; and (4) the application of the methodology to an existing structure. The numerical simulations of damage indicate that the proposed NDE method can clearly locate damage in the structures and provide an accurate quantitative value of damage severities, even when only a few lower frequencies and mode shapes are known. The field data analysis results indicate that the developed NDE method can locate damage and provide conservative values for damage severity estimations.

This thesis examines the effects of reinforcement ductility on the strength and ductility of reinforced concrete slabs. An extensive experimental program examining the ultimate strength, ductility and failure mode of one-way and two-way reinforced concrete slabs is described and the results are presented and analysed. A numerical finite element model is developed and calibrated using the experimental data. The model is described and shown to accurately simulate the collapse load behaviour of reinforced concrete slabs containing reinforcement of any ductility class, including Class L welded wire fabric. Parametric studies using the numerical model to assess the effects of reinforcement ductility on structural behaviour are also presented and recommendations are made on the minimum reinforcement ductility levels appropriate for use in suspended slabs. The experimental and numerical tests investigated slabs with different types of boundary conditions (simply supported and continuous one-way slabs, corner-supported single panel two slabs and edge-supported two-way slabs), support settlement, steel reinforcement ratio, steel uniform elongation (su), steel ultimate to yield stress ratio (fsu/fsy) and rectangularity aspect ratio in the two-way slabs. In total, thirty one slabs were tested. The one-way slabs included four simply supported slabs, seven continuous slabs, and five continuous slabs with support settlement. The two-way slabs included eleven square and rectangular corner-supported slabs and four rectangular edge-supported slabs. The one-way simply-supported slabs were 850mm in width, 100mm in depth and 2,500mm in length. The continuous one-way slabs were 850mm in width, 100mm in depth and 4,350mm in length. The continuous one-way slabs and subjected to support settlement were 850mm in width, 120mm in depth and 6,300mm in length. The square two-way slabs had an edge length of 2,400mm and a depth of 100mm and the rectangular two-way slabs had width of 2,400mm, a length of 3,600mm and a depth of 100mm.

This thesis examines the effects of reinforcement ductility on the strength and ductility of reinforced concrete slabs. An extensive experimental program examining the ultimate strength, ductility and failure mode of one-way and two-way reinforced concrete slabs is described and the results are presented and analysed. A numerical finite element model is developed and calibrated using the experimental data. The model is described and shown to accurately simulate the collapse load behaviour of reinforced concrete slabs containing reinforcement of any ductility class, including Class L welded wire fabric. Parametric studies using the numerical model to assess the effects of reinforcement ductility on structural behaviour are also presented and recommendations are made on the minimum reinforcement ductility levels appropriate for use in suspended slabs. The experimental and numerical tests investigated slabs with different types of boundary conditions (simply supported and continuous one-way slabs, corner-supported single panel two slabs and edge-supported two-way slabs), support settlement, steel reinforcement ratio, steel uniform elongation (su), steel ultimate to yield stress ratio (fsu/fsy) and rectangularity aspect ratio in the two-way slabs. In total, thirty one slabs were tested. The one-way slabs included four simply supported slabs, seven continuous slabs, and five continuous slabs with support settlement. The two-way slabs included eleven square and rectangular corner-supported slabs and four rectangular edge-supported slabs. The one-way simply-supported slabs were 850mm in width, 100mm in depth and 2,500mm in length. The continuous one-way slabs were 850mm in width, 100mm in depth and 4,350mm in length. The continuous one-way slabs and subjected to support settlement were 850mm in width, 120mm in depth and 6,300mm in length. The square two-way slabs had an edge length of 2,400mm and a depth of 100mm and the rectangular two-way slabs had width of 2,400mm, a length of 3,600mm and a depth of 100mm.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 196-206). Also available via the Internet.

Thesis (PhD) - Swinburne University of Technology, School of Engineering and Science, 2006. / A thesis submitted for the degree of Doctor of Philosophy, School of Engineering and Science, Swinburne University of Technology, 2006. Typescript. Includes bibliographical references (p. 125-138).