Within the set of all vehicle crashes that occur annually, of intersection-related crashes are over-represented. The research conducted here uses an empirical approach to study driver behavior at intersections, in a naturalistic paradigm. A data-mining algorithm was used to aggregate the data from two different naturalistic databases to obtain instances of unprotected turns at the same intersection. Several dependent variables were analyzed which included visual entropy, mean-duration of glances to locations in the driver's view, gap-acceptance/rejection time. Kinematic dependent variables include peak/average speed, and peak longitudinal and lateral acceleration. Results indicated that visual entropy and peak speed differs amongst drivers of the three age-groups (older, middle-age, teens) in the presence of traffic in the intersecting streams while negotiating a left turn. Although not significant, but approaching significance, were differences in gap acceptance times, with the older driver accepting larger gaps compared to the younger teen drivers. Significant differences were observed for peak speed and average speed during a left turn, with younger drivers exhibiting higher values for both. Overall, this research has resulted in contribution towards two types of engineering application. Firstly, the analyses of traffic levels, gap acceptance, and gap non-acceptance represented exploratory efforts, ones that ventured into new areas of technical content, using newly available naturalistic driving data. Secondly, the findings from this thesis are among the few that can be used to inform the further development, refinement, and testing of technology (and training) solutions intended to assist drivers in making successful turns and avoiding crashes at intersections. / Master of Science

Magister Psychologiae - MPsych / HIV poses considerable social and health challenges in South Africa, particularly among young people aged 15-24. Research indicates a strong link between risky sexual behaviour and alcohol and illicit drugs. In the Western Cape drug-related behaviours is a growing concern among young people because of relatively high prevalence rates of drug abuse, particularly methamphetamine. Previous South African studies have tended to focused on the link between substance use and risky sexual behaviour among commercial sex workers. The theoretical approach of this study is the information motivation behavioural skills model. Participants were selected using non-probability sampling of 279 first year students registered for Psychology I at the University of the Western Cape. This study employed a quantitative research approach using a survey design. Results: Forty-six percent of students do not believe that the use of illicit drugs has an impact on a person's sexual behavior. However, the findings also showed that only 45% of students believed that there was a difference between illicit drug users correctly using condoms when compared to non-users. Data was analysed using descriptive and inferential statistics. Conclusion: Prevention is our best and most effective means of decreasing risk-taking behaviours associated with HIV infection. Information is the first line of intervention that is necessary to reduce risk-taking behaviours; however prevention strategies and interventions of risk-taking behaviours should aim to increase motivation and help young people integrate information in a way that it is personally relatable. This is vital to address the inconsistencies between perceptions of risk and the realities of risk-taking behaviour. / South Africa

The growing population and motorization generate more movements. In many cities, the increase of population and motorization is much greater than the development of the capacity of the transportation network. For unprotected road users, the risk of getting in a traffic accident increases and the risk of being more severely injured in an accident. In March 2020, a pandemic was declared because of a Coronavirus. More people started to work/study from home to prevent the virus from spreading by avoiding unnecessary trips, gatherings, and crowded areas. Therefore, travel behaviours have shifted during the pandemic compared to previous years. This project aims to get knowledge of how mobility and traffic accidents are affected by significant shifts of travel flow, predict the effect of traffic accidents based on mobility, and evaluate the risk of travelling on a particular road segment. / <p>Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet</p>

Traffic accidents is one of the major causes of fatalities and economic loss around the world. Thus, there is an urgent need for a better understanding about the factors that contribute to accidents so that the accidents can be prevented in the future. The research objective of this thesis is to analyze the traffic accidents between vehicles and unprotected road users (pedestrians and bicycles) in Stockholm, finding spatial distribution patterns, related attributes and examining relationships between accidents and a number of vehicle flows. The data is first analyzed with general statistical analysis to examine the basic characteristics. There is no apparent trend of change among the number of accidents per year, while the numbers of accidents happening from May to October is higher than the rest of the year except for July due to less traffic during holiday period. Most traffic accidents occur in overcast weather, on a dry road surface, or during the day. In the spatial analysis part of the thesis, Global Moran’s I is used to detect whether there is an attribute-related spatial distribution pattern. Hot spot analysis is then applied on the clustered attributes to find significant hot and cold spots over the study area. The conclusions are that road surface conditions and occurrence time during day/night are two related factors that influence traffic accidents while weather is not considered a related attribute since the accidents distribute randomly in terms of weather, of which it is difficult to obtain temporally-aligned, detailed local information for further analysis. Different parameters are selected and discussed during the process. When calculating the distance between two accidents in traffic accident analysis, Manhattan distance is more appropriate than Euclidean distance since traffic accidents are restricted to the road network. The distance band determines scales of analysis tools, with 50 meters on an intersection and 500 meters for a larger region in Stockholm. Most hot spots arise at intersections and roundabouts where different types of traffic flows meet each other. The result of the relationships between traffic accidents and different types of vehicle flows shows that the correlation coefficients between number of traffic accidents and traffic flows are low, meaning that there is no obvious correlation between them, which is also proved by the scatter plots. Poisson regression model is applied on the traffic accident data. As a result, high-risk and low-risk areas in Stockholm are pointed out. Some are consistent with the hot-spot analysis result.

Crashes categorized as running red light or left turning are most likely to occur at signalized intersections and resulted in substantial severe injuries and property damages. This dissertation mainly focused on these two types of vehicle crashes and the research methodology involved several perspectives. To examine the overall characteristics of red-light running and left-turning crashes, firstly, this study applied 1999-2001 Florida traffic crash data to investigate the accident propensity of three aspects of risk factors related to traffic environments, driver characteristics, and vehicle types. A quasi-induced exposure concept and statistical techniques including classification tree model and multiple logistic regression were used to perform this analysis. Secondly, the UCF driving simulator was applied to test the effect of a proposed new pavement marking countermeasure which purpose is to reduce the red-light running rate at signalized intersections. The simulation experiment results showed that the total red-light running rate with marking is significantly lower than that without marking. Moreover, deceleration rate of stopping drivers with marking for the higher speed limit are significantly less than those without marking. These findings are encouraging and suggesting that the pavement marking may result in safety enhancement as far as right-angle and rear-end traffic crashes at signalized intersections. Thirdly, geometric models to compute sight distances of unprotected left-turns were developed for different signalized intersection configurations including a straight approach leading to a straight one, a straight approach leading to a curved one, and a curved approach leading to a curved one. The models and related analyses can be used to layout intersection design or evaluate the sight distance problem of an existing intersection configuration to ensure safe left-turn maneuvers by drivers.

This study described sexual behaviours among adolescents living with the Human Immunodeficiency Virus (HIV) in Zimbabwe. This study utilised a quantitative descriptive design. Data was collected using structured questionnaires from 341 adolescents living with HIV. Findings revealed that some adolescents were sexually active and had early onset of sexual activity (before their sixteenth birthday). A good proportion of sexually active adolescents were noted not to practise safer sex and the main reason was condom inaccessibility and some had multiple sex partners. Factors independently associated with being sexually active included exposure to erotic content on television programmes, having a psychiatric diagnosis, discussions of sexuality with health worker and older age. Adolescents` behaviours living with HIV and the issue of availability of condoms may play a part in the spread of HIV. More discussions and research on sexuality of adolescents are recommended / Health Studies / M.A. (Public Health)

Im Rahmen der vorliegenden Dissertation wurden drei neue Zugangswege zu kettenverlängerten Kohlenhydraten aus ungeschützten Aldosen entwickelt. Dabei ermöglichen diese Protokolle die Synthese verschiedener Klassen von kettenverlängerten Strukturen. Neben der selektiven Darstellung von 2-Ketoaldonsäurederivaten konnten effiziente Zugangsstrategien zu hoch funktionalisierten bizyklischen C-Glycosiden und polyhydroxylierten Pseudopeptiden präsentiert werden. Dabei konnte gezeigt werden, dass ein breites Spektrum dieser verschiedenen Arten kettenverlängerter Kohlenhydrate aus ungeschützten natürlichen Hexose- und Pentose-Substraten zugänglich ist. Durch den Einbezug der natürlich vorhandenen Hydroxylgruppen der Aldosen ermöglichen die präsentierten Kaskadenreaktionen einen sehr effektiven Zugang zu hoch funktionalisierten Produkten, welche in Sequenzen unter Verwendung von Schützungsstrategien nur in aufwendigen, mehrstufigen Reaktionen zugänglich wären. Zudem konnte gezeigt werden, dass die natürlich vorkommende Chiralität in den verwendeten Substraten für ein stereoselektives Dirigieren der neu installierten Stereozentren nutzbar ist. Damit konnte eine bedeutende Erweiterung des bestehenden Repertoires von Methoden für die Verlängerung ungeschützter Kohlenhydrate erreicht werden.. Die entwickelten Transformationen bestechen durch ihre hohe Atomökonomie, wie auch durch ihre sehr gute ökologische und ökonomische Bilanz und erfüllen damit die Anforderungen an nachhaltige Synthesemethoden. / The scope of the presented work was the investigation of new organocatalysed synthesis strategies of carbon chain elongated carbohydrates. Here three new accesses to three different structure motifs of these biologically highly important and manifold compounds from unprotected carbohydrates were developed. Using naturally occurring, unprotected pentoses and hexoses, a wide variety of keto aldonic acids, bicyclic C-glycosides and glycosylated pseudopeptides are accessible in three different cascade reactions. All of the presented strategies enable the C-chain elongation by employment of the naturally occurring aldehyde motive without tedious protection ad deprotection protocols or synthetic modifications of the substrates. By utilisation of the chiral hydroxyl moieties of the carbohydrate chain, diastereoselective control of the installation of the stereocenters formed in the cascade reactions is achieved. The high regio- and diastereoselectivities, high yields as well as the convenient synthesis conditions of the presented protocols make the presented cascade reactions valuable tools among the already described accesses to the biological important compounds of chain elongated carbohydrates. The presented cascades enable the diastereoselective synthesis of a high variety of these motifs in only one synthetic step from readily available unprotected carbohydrates without additional modification steps. These advantages give rise to a very high atom economy of the transformations, which therefore fulfil the requirements to green chemistry and sustainable synthesis methods.

Este trabalho busca compreender as formas de relações de trabalho que estão à margem do assalariamento e suas consequências e perspectivas para a relação entre estado e sociedade no que se refere ao mundo do trabalho. A literatura tradicionalmente chamou os trabalhadores envolvidos nestas formas de relações laborais de informais ou atípicos. Neste sentido, foram tradicionalmente compreendidos, tanto academicamente como politicamente, na chave da falta e da impossibilidade da política. Contudo, se é verdade que do ponto de vista das instituições tradicionais relativas ao mundo do trabalho (sindicatos, estado e suas formas jurídicas de regulação do trabalho) elas de fato ainda são estranhas e não nomeáveis senão pela falta, no contexto das transformações econômicas e políticas ocorridas na últimas décadas, estas formas de relações laborais são constitutivos tanto do atual modelo de acumulação como também criam novos campos de conflitos, e a partir deles estão buscando se organizar politicamente, construir identidade e colocar sua agenda para o trabalho. Buscou-se assim, na primeira parte deste texto, compreender o significado teórico e político que as formas de trabalho não assalariadas tiveram e tem para o mundo do trabalho. Na segunda parte, a partir de uma discussão centrada na chamada economia solidária, se busca compreender a emergência desta nova realidade e a constituição de novos sujeitos políticos no mundo do trabalho, com identidade e agenda próprias. Contudo, se por um lado, neste processo de constituição de novos sujeitos políticos, estas formas de trabalho e seus trabalhadores ficam além da informalidade, por outro, ainda não conseguiram ser reconhecidos, em sua relação com o estado, como sujeitos portadores de direitos. / This work aims to examine the non-wage based labour relations and understand its implications for the State and Society. These kinds of labour relations have been referred to as \"informal\" or \"non typical\". In this sense, they have been viewed academically and politically as lacking or unviable. However, if it is true that from the perspective of the traditional labour institutions (Unions, State, and the juridical forms of labour regulation) these labour relations are aliens and cannot be characterized but for absence of the key attributes that traditionally have defined labour, in the context of political and economical changes that took place in the past decades, these labour relations are an important part of the accumulation model and have generated new fields of conflict and have been trying to get politically organized, building identity and pushing forward with their agenda. The first part of the work focus on understanding the theoretical and political implications of the non wage based relations for labour relations in general. On the second part, based on a discussion around \"solidary economy\', we try to understand the emergence of this new reality and the development of new political subjects with their own agendas and identities. However, although these labour relations and its workers are not informal, they still not recognized in their relation with the State as having rights.

Este trabalho busca compreender as formas de relações de trabalho que estão à margem do assalariamento e suas consequências e perspectivas para a relação entre estado e sociedade no que se refere ao mundo do trabalho. A literatura tradicionalmente chamou os trabalhadores envolvidos nestas formas de relações laborais de informais ou atípicos. Neste sentido, foram tradicionalmente compreendidos, tanto academicamente como politicamente, na chave da falta e da impossibilidade da política. Contudo, se é verdade que do ponto de vista das instituições tradicionais relativas ao mundo do trabalho (sindicatos, estado e suas formas jurídicas de regulação do trabalho) elas de fato ainda são estranhas e não nomeáveis senão pela falta, no contexto das transformações econômicas e políticas ocorridas na últimas décadas, estas formas de relações laborais são constitutivos tanto do atual modelo de acumulação como também criam novos campos de conflitos, e a partir deles estão buscando se organizar politicamente, construir identidade e colocar sua agenda para o trabalho. Buscou-se assim, na primeira parte deste texto, compreender o significado teórico e político que as formas de trabalho não assalariadas tiveram e tem para o mundo do trabalho. Na segunda parte, a partir de uma discussão centrada na chamada economia solidária, se busca compreender a emergência desta nova realidade e a constituição de novos sujeitos políticos no mundo do trabalho, com identidade e agenda próprias. Contudo, se por um lado, neste processo de constituição de novos sujeitos políticos, estas formas de trabalho e seus trabalhadores ficam além da informalidade, por outro, ainda não conseguiram ser reconhecidos, em sua relação com o estado, como sujeitos portadores de direitos. / This work aims to examine the non-wage based labour relations and understand its implications for the State and Society. These kinds of labour relations have been referred to as \"informal\" or \"non typical\". In this sense, they have been viewed academically and politically as lacking or unviable. However, if it is true that from the perspective of the traditional labour institutions (Unions, State, and the juridical forms of labour regulation) these labour relations are aliens and cannot be characterized but for absence of the key attributes that traditionally have defined labour, in the context of political and economical changes that took place in the past decades, these labour relations are an important part of the accumulation model and have generated new fields of conflict and have been trying to get politically organized, building identity and pushing forward with their agenda. The first part of the work focus on understanding the theoretical and political implications of the non wage based relations for labour relations in general. On the second part, based on a discussion around \"solidary economy\', we try to understand the emergence of this new reality and the development of new political subjects with their own agendas and identities. However, although these labour relations and its workers are not informal, they still not recognized in their relation with the State as having rights.

<p>HIV poses considerable social and health challenges in South Africa, particularly among young people aged 15-24. Research indicates a strong link between risky sexual behaviour and alcohol and illicit drugs. In the Western Cape drug-related behaviours is a growing concern among young people because of relatively high prevalence rates of drug abuse, particularly methamphetamine. Previous South African studies have tended to focused on the link between substance use and risky sexual behaviour among commercial sex workers. The theoretical approach of this study is the information motivation behavioural skills model. Participants were selected using non-probability sampling of 279 first year students registered for Psychology I at the University of the Western Cape. This study employed a quantitative research approach using a survey design. Results: Forty-six percent of students do not believe that the use of illicit drugs has an impact on a person&rsquo / s sexual behavior. However, the findings also showed that only 45% of students believed that there was a difference between illicit drug users correctly using condoms when compared to non-users. Data was analysed using descriptive and inferential statistics. Conclusion: Prevention is our best and most effective means of decreasing risk-taking behaviours associated with HIV infection. Information is the first line of intervention that is necessary to reduce risk-taking behaviours / however prevention strategies and interventions of risk-taking behaviours should aim to increase motivation and help young people integrate information in a way that it is personally relatable. This is vital to address the inconsistencies between perceptions of risk and the realities of risk-taking behaviour.</p>