A common practice in multi-national enterprises is to staff important managerial roles in overseas operations with personnel from the company’s country of origin: expatriate managers. Homecoming expatriates often experience that the competence they have acquired abroad is not recognized when returning home. The purpose of this thesis is to explore how expatriates experience that international assignments affect their careers. The theoretical framework used includes sociological theories from neo-Marxist theory, Bourdieuan career theory and expectancy theory. This thesis uses qualitative methodology and a phenomenological approach to investigate the purpose and the research questions. The empirical part of the thesis has been conducted in two phases where five international mobility managers have been interviewed in the first phase. In the second phase interviews where held at a multi-national Swedish headquartered company where five interviews were conducted. The results indicate that there is a discrepancy between how company representatives (managers) and employees consider international assignments and expatriation in relation to employee careers. There seems to be a lack of clear understanding of the impact of expatriation on employee careers and also of the career value of an international assignment for an employee.

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Falling, an epidemic most prevalently seen in the elderly population, accounts for the majority of injury-related cases seen by emergency departments across the United States. Unfortunately, with no large-scale institutionalization of a solution, the problem is only expected to exacerbate as our planet’s population approaches the 7 billion mark. In the wake of the recent surge of falls among the elderly, Japan has implemented a program to include unicycling in the physical education curriculum for elementary schools across the country. The goal for this program is to encourage children to establish strong fundamental balancing skills, which could potentially alleviate the pain—physical, emotional, and financial—incurred from falls in the elderly. This senior thesis study builds off Japan’s unicycling program by investigating ways to improve wobble board balancing, a more practical alternative to unicycling. In previous research, the skill of stick balancing, a motor task that has been shown to behave with the same power laws as wobble board balancing, has been improved with the use of vibrations. Here, we show that learning to wobble board balance is not expedited and wobble board balancing skill is not improved with the employment of vibrations, unlike stick balancing. Nonetheless, those who learned to wobble board balance with background vibrations went on to later outperform those who learned to wobble board balance without vibrations. These results suggest that vibrations (50 Hz, 0.18 mm amplitude) have a beneficial effect on the development of skill for wobble board balancing that is not related to the direct physical effects of the vibration. The observations also suggest that in the presence of vibrations, the nervous system develops more robust strategies for controlling balance.

Children with disabilities in school settings often display problem behavior. These challenging behaviors can be inattention, disruptions in class, difficulties with transitions between tasks, and low task motivation. These types of behaviors can lead to problems for the students with their peers, teachers, and school staff. One way to decrease problem behavior is to implement antecedent manipulations to prevent problem behavior from ever occurring. One type of antecedent manipulation is using alternative seating in the classroom, such as stability balls or stabili-t stools. However, little research has been conducted to evaluate different types of alternative seating, therefore this study used an alternating treatments design to evaluate the effects of stability balls versus stabili-t stools on in-seat and on-task behavior in an academic setting. Results indicated increases in both in-seat and on-task behavior with the use of both alternative types of seating. In-seat behavior increased more substantially then on-task behavior with alternative seating. Social validity results indicated that stability balls were not well liked by teachers and therapists, however the stabili-t stools were found to be acceptable. Both types of alternative seating were chosen by participants in the choice phase, however the stabili-t stool was chosen more often.

In human impacts involving high peak accelerations, the wobbling mass (skin, muscle, fat, and connective tissue) of the body will accelerate independently of the rigid mass (bone) . The purpose of this study was to quantify the effect that below knee wobbling mass has, if any, on the attenuation of peak forces transmitted through the leg to the knee joint, following impacts with the ground. Fifteen healthy subjects dropped vertically from heights of 5 and 10 cm, onto a force platform, with the ankle and knee joints of the support leg held rigidly. A uni-axial accelerometer was fixed, with skin bond cement, to the skin overlying the anterior upper tibia, and another to the posterior wobbling tissue of the support limb. Vertical ground reaction forces and accelerations were used in rigid only and rigid and wobbling link segment models of the leg, which resulted in estimates of vertical knee joint reaction forces (VKJRF). Mean peak VKJRFs resulting from rigid only calculations were 2.66±.55 x body weight (bw) and 3.53±.68 x bw, and from rigid and wobbling calculations were 2.64±.55 x bw and 3.52±.68 x bw, for the 5 and 10 cm heights, respectively. A two-way, repeated measures ANOVA revealed that there was no main effect for calculation method. Validation of the subject results was attempted indirectly by comparing them to the actual forces (load cell) at the knee of a manufactured model. The model was constructed in proportion to a human subject of mass 75 kg. When the model was dropped from the same heights as the subjects, the mean peak VKJRFs (22. 9 x bw) greatly overestimated the actual load cell values (8.2 x bw), and were unrealistic relative to subject values (approximately 3.0 x bw). Although mean peak VKJRFs were also overestimated when the wobbling mass accelerations were included, they were much closer to the actual values (9.9 x bw vs. 8.2 x bw). / Thesis / Master of Science (MS)

<p>A mechanical model of an axial piston-type machine with a so-called wobble plate and Z-shaft mechanism is presented. The overall aim is to design and construct an oil-free piston expander demonstrator as a first step to realizing an advanced and compact small-scale steam engine system. The benefits of a small steam engine are negligible NOx emissions (due to continuous, low-temperature combustion), no gearbox needed, fuel flexibility (e.g., can run on biofuel and solar), high part-load efficiency, and low noise. Piston expanders, compared with turbines or clearance-sealed rotary displacement machines, have higher mechanical losses but lower leakage losses, much better part-load efficiency, and for many applications a more favourable (i.e., lower) speed. A piston expander is thus feasible for directly propelling small systems in the vehicular power range. An axial piston machine with minimized contact pressures and sliding velocities, and with properly selected construction materials for steam/water lubrication, should enable completely oil-free operation. An oil-free piston machine also has potential for other applications, for example, as a refrigerant (e.g., CO₂) expander in a low-temperature Rankine cycle or as a refrigerant compressor.</p><p> </p><p>An analytical rigid-body kinematics and inverse dynamics model of the machine is presented. The kinematical analysis generates the resulting motion of the integral parts of the machine, fully parameterized. Inverse dynamics is applied when the system motion is completely known, and the method yields required external and internal forces and torques. The analytical model made use of the “Sophia” plug-in developed by Lesser for the simple derivation of rotational matrices relating different coordinate systems and for vector differentiation. Numerical solutions were computed in MATLAB. The results indicate a large load bearing in the conical contact surface between the mechanism’s wobble plate and engine block. The lateral force between piston and cylinder is small compared with that of a comparable machine with a conventional crank mechanism.</p><p> </p><p>This study aims to predict contact loads and sliding velocities in the component interfaces. Such data are needed for bearing and component dimensioning and for selecting materials and coatings. Predicted contact loads together with contact geometries can also be used as input for tribological rig testing. Results from the model have been used to dimension the integral parts, bearings and materials of a physical demonstrator of the super-critical steam expander application as well as in component design and concept studies.</p>

Mutations found in genes encoding human Elongator complex subunits have been linked to neurodevelopmental disorders such as familial dysautonomia (FD), rolandic epilepsy and amyotrophic lateral sclerosis. In addition, loss-of-function mutations in genes encoding Elongator complex subunits cause defects in neurodevelopment and reduced neuronal function in both mice and nematodes. The Elongator complex is a conserved protein complex comprising six subunits (Elp1p-Elp6p) found in eukaryotes. The primary function of this complex in yeast is formation of the 5-methoxycarbonylmethyl (mcm5) and 5-carbamoylmethyl (ncm5) side chains found on wobble uridines (U34) in tRNAs. The aim of this thesis is to investigate the physiological consequences of Elongator complex inactivation in humans and in the yeast Saccharomyces cerevisiae. Inactivation of the Elongator complex causes widespread defects in a multitude of different cellular processes in S. cerevisiae. Thus, we investigated metabolic alterations resulting from Elongator complex inactivation. We show that deletion of the S. cerevisiae ELP3 gene leads to widespread metabolic alterations. Moreover, all global metabolic alterations observed in the elp3Δ strain are not restored in the presence of elevated levels of hypomodified tRNAs that normally have the modified nucleoside mcm5s2U. Collectively, we show that modified wobble nucleosides in tRNAs are required for metabolic homeostasis. Elongator mutants display sensitivity to DNA damage agents, but the underlying mechanism explaining this sensitivity remains elusive. We demonstrate that deletion of the S. cerevisiae ELP3 gene results in post-transcriptional reduction of Ixr1p levels. Further, we show that the reduced Ixr1p levels prevent adequate Rnr1p levels upon treatment with DNA damage agents. These findings suggest that reduced Ixr1p levels could in part explain why Elongator mutants are sensitive to DNA damage agents. Depletion of Elongator complex subunits results in loss of wobble uridine modifications in plants, nematodes, mice and yeast. Therefore, we investigated whether patients with the neurodegenerative disease familial dysautonomia (FD), who have lower levels of the ELP1 protein, display reduced amounts of modified wobble uridine nucleosides. We show that tRNA isolated from brain tissue and fibroblast cell lines derived from FD patients have 64–71% of the mcm5s2U nucleoside levels observed in total tRNA from non-FD brain tissue and non-FD fibroblasts. Overall, these results suggest that the cause for the neurodegenerative nature of FD could be translation impairment caused by reduced levels of modified wobble uridine nucleosides in tRNAs. Thus, our results give new insight on the importance of modified wobble uridine nucleosides for neurodevelopment.

Transfer RNAs (tRNAs) act as adaptor molecules in decoding messenger RNA into protein. Frequently found in tRNAs are different modified nucleosides, which are derivatives of the four normal nucleosides, adenosine (A), guanosine (G), cytidine (C), and uridine (U). Although modified nucleosides are present at many positions in tRNAs, two positions in the anticodon region, position 34 (wobble position) and position 37, show the largest variety of modified nucleosides. In Saccharomyces cerevisiae, the xm5U type of modified uridines found at position 34 are 5-carbamoylmethyluridine (ncm5U), 5-carbamoylmethyl-2´-O-methyluridine, (ncm5Um), 5-methoxycarbonylmethyluridine (mcm5U), and 5-methoxycarbonyl-methyl-2-thiouridine (mcm5s2U). Based on the complex structure of these nucleosides, it is likely that their formation requires several synthesis steps. The Elongator complex consisting of proteins Elp1p - Elp6p, and the proteins Kti11p - Kti14p, Sit4p, Sap185p, and Sap190p were shown to be involved in 5-carbamoylmethyl (ncm5) and 5-methoxycarbonylmethyl (mcm5) side-chain synthesis at position 34 in eleven tRNA species. The proteins Urm1p, Uba4p, Ncs2p, Ncs6p, and Yor251cp were also identified to be required for the 2-thio (s2) group formation of the modified nucleoside mcm5s2U at wobble position. Modified nucleosides in the anticodon region of tRNA influence the efficiency and fidelity of translation. The identification of mutants lacking ncm5-, mcm5-, or s2-group at the wobble position allowed the investigation of the in vivo role of these nucleosides in the tRNA decoding process. It was revealed that the presence of ncm5-, mcm5- or s2-group promotes reading of G-ending codons. The concurrent presence of the mcm5- and the s2-groups in the wobble nucleoside mcm5s2U improves reading of A- and G-ending codons, whereas absence of both groups is lethal to the yeast cell. The Elongator complex was previously proposed to regulate polarized exocytosis and to participate in elongation of RNA polymerase II transcription. The pleiotropic phenotypes observed in Elongator mutants were therefore suggested to be caused by defects in exocytosis and transcription of many genes. Here it is shown that elevated levels of hypomodified tRNALys [mcm5s2UUU] and tRNAGln[mcm5s2UUG] can efficiently suppress these pleiotropic phenotypes, suggesting that the defects in transcription and exocytosis are indirectly caused by inefficient translation of mRNAs encoding proteins important in these processes.

Transfer RNA from all organisms has modified nucleosides and position 34 (the wobble position) is one of the most extensively modified positions. Some wobble nucleoside modifications restrict codon choice (e.g. 5-methylaminomethyl-2-thiouridine, mnm5s2U) while some extend the decoding capacity (e.g. uridine-5-oxyacetic acid, cmo5U). In this thesis the influence of wobble nucleoside modification on cell physiology and translation efficiency and accuracy is described. A mutant proL tRNA (proL207) was isolated that had an unmodified adenosine in the wobble position. Surprisingly, the proL207 mutant grows normally and is efficiently selected at the non-complementary CCC codon. The explanation of how an A34 containing tRNA can read CCC codon could be that a protonated A can form a base pair with C. cmo5U (uridine-5-oxyacetic acid) is present in the wobble position of five tRNA species in S.enterica. Two genes (cmoA and cmoB) have been identified that are involved in the synthetic pathway of cmo5U. Mutants were constructed in alanine, valine, proline, and threonine codon boxes which left only a cmo5U containing tRNA present in the cell. The influence of cmo5U on growth or on A site selection rates of the ternary complex was found to be tRNA dependent. During the study of the frameshift suppressor sufY of the hisC3737 frameshift mutation, a dominant mutation was found in YbbB protein, a selenouridine synthetase. The frameshifting occurs at CCC-CAA codon contexts and is specific for CAA codons, which are read by tRNAGlncmnm5s2UUG . The sufY204 mutation is a dominant mutation resulting in a change from Gly67 to Glu67 in the YbbB protein, and mediates the synthesis of several novel modified nucleosides/nucleotides (UKs) with unknown structure. The synthesis of these UKs is connected to the synthesis of cmnm5s2U34. The presence of UK on tRNAGlnU*UG reduced aminoacylation and therefore might account for the slow entry at CAA codons which could result in +1 frameshifting by P site tRNA. The selenourdine synthetase activity is not required for the synthesis of UKs. We hypothesize that an intrinsic activity that is low in the wild type protein has been elevated by the single amino acid substitution and results in the synthesis of UKs.

A mechanical model of an axial piston-type machine with a so-called wobble plate and Z-shaft mechanism is presented. The overall aim is to design and construct an oil-free piston expander demonstrator as a first step to realizing an advanced and compact small-scale steam engine system. The benefits of a small steam engine are negligible NOx emissions (due to continuous, low-temperature combustion), no gearbox needed, fuel flexibility (e.g., can run on biofuel and solar), high part-load efficiency, and low noise. Piston expanders, compared with turbines or clearance-sealed rotary displacement machines, have higher mechanical losses but lower leakage losses, much better part-load efficiency, and for many applications a more favourable (i.e., lower) speed. A piston expander is thus feasible for directly propelling small systems in the vehicular power range. An axial piston machine with minimized contact pressures and sliding velocities, and with properly selected construction materials for steam/water lubrication, should enable completely oil-free operation. An oil-free piston machine also has potential for other applications, for example, as a refrigerant (e.g., CO2) expander in a low-temperature Rankine cycle or as a refrigerant compressor.   An analytical rigid-body kinematics and inverse dynamics model of the machine is presented. The kinematical analysis generates the resulting motion of the integral parts of the machine, fully parameterized. Inverse dynamics is applied when the system motion is completely known, and the method yields required external and internal forces and torques. The analytical model made use of the “Sophia” plug-in developed by Lesser for the simple derivation of rotational matrices relating different coordinate systems and for vector differentiation. Numerical solutions were computed in MATLAB. The results indicate a large load bearing in the conical contact surface between the mechanism’s wobble plate and engine block. The lateral force between piston and cylinder is small compared with that of a comparable machine with a conventional crank mechanism.   This study aims to predict contact loads and sliding velocities in the component interfaces. Such data are needed for bearing and component dimensioning and for selecting materials and coatings. Predicted contact loads together with contact geometries can also be used as input for tribological rig testing. Results from the model have been used to dimension the integral parts, bearings and materials of a physical demonstrator of the super-critical steam expander application as well as in component design and concept studies.