573 research outputs found
Examining psychosocial influences on speeding in Australian and Chinese contexts : a social learning approach
Speeding remains a significant contributing factor to road trauma internationally, despite increasingly sophisticated speed management strategies being adopted around the world. Increases in travel speed are associated with increases in crash risk and crash severity. As speed choice is a voluntary behaviour, driver perceptions are important to our understanding of speeding and, importantly, to designing effective behavioural countermeasures. The four studies conducted in this program of research represent a comprehensive approach to examining psychosocial influences on driving speeds in two countries that are at very different levels of road safety development: Australia and China. Akers’ social learning theory (SLT) was selected as the theoretical framework underpinning this research and guided the development of key research hypotheses. This theory was chosen because of its ability to encompass psychological, sociological, and criminological perspectives in understanding behaviour, each of which has relevance to speeding. A mixed-method design was used to explore the personal, social, and legal influences on speeding among car drivers in Queensland (Australia) and Beijing (China).
Study 1 was a qualitative exploration, via focus group interviews, of speeding among 67 car drivers recruited from south east Queensland. Participants were assigned to groups based on their age and gender, and additionally, according to whether they self-identified as speeding excessively or rarely. This study aimed to elicit information about how drivers conceptualise speeding as well as the social and legal influences on driving speeds. The findings revealed a wide variety of reasons and circumstances that appear to be used as personal justifications for exceeding speed limits. Driver perceptions of speeding as personally and socially acceptable, as well as safe and necessary were common. Perceptions of an absence of danger associated with faster driving speeds were evident, particularly with respect to driving alone. An important distinction between the speed-based groups related to the attention given to the driving task. Rare speeders expressed strong beliefs about the need to be mindful of safety (self and others) while excessive speeders referred to the driving task as automatic, an absent-minded endeavour, and to speeding as a necessity in order to remain alert and reduce boredom. For many drivers in this study, compliance with speed limits was expressed as discretionary rather than mandatory.
Social factors, such as peer and parental influence were widely discussed in Study 1 and perceptions of widespread community acceptance of speeding were noted. In some instances, the perception that ‘everybody speeds’ appeared to act as one rationale for the need to raise speed limits. Self-presentation, or wanting to project a positive image of self was noted, particularly with respect to concealing speeding infringements from others to protect one’s image as a trustworthy and safe driver. The influence of legal factors was also evident. Legal sanctions do not appear to influence all drivers to the same extent. For instance, fear of apprehension appeared to play a role in reducing speeding for many, although previous experiences of detection and legal sanctions seemed to have had limited influence on reducing speeding among some drivers. Disregard for sanctions (e.g., driving while suspended), fraudulent demerit point use, and other strategies to avoid detection and punishment were widely and openly discussed.
In Study 2, 833 drivers were recruited from roadside service stations in metropolitan and regional locations in Queensland. A quantitative research strategy assessed the relative contribution of personal, social, and legal factors to recent and future self-reported speeding (i.e., frequency of speeding and intentions to speed in the future). Multivariate analyses examining a range of factors drawn from SLT revealed that factors including self-identity (i.e., identifying as someone who speeds), favourable definitions (attitudes) towards speeding, personal experiences of avoiding detection and punishment for speeding, and perceptions of family and friends as accepting of speeding were all significantly associated with greater self-reported speeding.
Study 3 was an exploratory, qualitative investigation of psychosocial factors associated with speeding among 35 Chinese drivers who were recruited from the membership of a motoring organisation and a university in Beijing. Six focus groups were conducted to explore similar issues to those examined in Study 1. The findings of Study 3 revealed many similarities with respect to the themes that arose in Australia. For example, there were similarities regarding personal justifications for speeding, such as the perception that posted limits are unreasonably low, the belief that individual drivers are able to determine safe travel speeds according to personal comfort with driving fast, and the belief that drivers possess adequate skills to control a vehicle at high speed. Strategies to avoid detection and punishment were also noted, though they appeared more widespread in China and also appeared, in some cases, to involve the use of a third party, a topic that was not reported by Australian drivers. Additionally, higher perceived enforcement tolerance thresholds were discussed by Chinese participants. Overall, the findings indicated perceptions of a high degree of community acceptance of speeding and a perceived lack of risk associated with speeds that were well above posted speed limits.
Study 4 extended the exploratory research phase in China with a quantitative investigation involving 299 car drivers recruited from car washes in Beijing. Results revealed a relatively inexperienced sample with less than 5 years driving experience, on average. One third of participants perceived that the certainty of penalties when apprehended was low and a similar proportion of Chinese participants reported having previously avoided legal penalties when apprehended for speeding. Approximately half of the sample reported that legal penalties for speeding were ‘minimally to not at all’ severe. Multivariate analyses revealed that past experiences of avoiding detection and punishment for speeding, as well as favourable attitudes towards speeding, and perceptions of strong community acceptance of speeding were most strongly associated with greater self-reported speeding in the Chinese sample.
Overall, the results of this research make several important theoretical contributions to the road safety literature. Akers’ social learning theory was found to be robust across cultural contexts with respect to speeding; similar amounts of variance were explained in self-reported speeding in the quantitative studies conducted in Australia and China. Historically, SLT was devised as a theory of deviance and posits that deviance and conformity are learned in the same way, with the balance of influence stemming from the ways in which behaviour is rewarded and punished (Akers, 1998). This perspective suggests that those who speed and those who do not are influenced by the same mechanisms. The inclusion of drivers from both ends of the ‘speeding spectrum’ in Study 1 provided an opportunity to examine the wider utility of SLT across the full range of the behaviour. One may question the use of a theory of deviance to investigate speeding, a behaviour that could, arguably, be described as socially acceptable and prevalent. However, SLT seemed particularly relevant to investigating speeding because of its inclusion of association, imitation, and reinforcement variables which reflect the breadth of factors already found to be potentially influential on driving speeds. In addition, driving is a learned behaviour requiring observation, guidance, and practice. Thus, the reinforcement and imitation concepts are particularly relevant to this behaviour. Finally, current speed management practices are largely enforcement-based and rely on the principles of behavioural reinforcement captured within the reinforcement component of SLT. Thus, the application of SLT to a behaviour such as speeding offers promise in advancing our understanding of the factors that influence speeding, as well as extending our knowledge of the application of SLT. Moreover, SLT could act as a valuable theoretical framework with which to examine other illegal driving behaviours that may not necessarily be seen as deviant by the community (e.g., mobile phone use while driving).
This research also made unique contributions to advancing our understanding of the key components and the overall structure of Akers’ social learning theory. The broader SLT literature is lacking in terms of a thorough structural understanding of the component parts of the theory. For instance, debate exists regarding the relevance of, and necessity for including broader social influences in the model as captured by differential association. In the current research, two alternative SLT models were specified and tested in order to better understand the nature and extent of the influence of differential association on behaviour. Importantly, the results indicated that differential association was able to make a unique contribution to explaining self-reported speeding, thereby negating the call to exclude it from the model. The results also demonstrated that imitation was a discrete theoretical concept that should also be retained in the model. The results suggest a need to further explore and specify mechanisms of social influence in the SLT model.
In addition, a novel approach was used to operationalise SLT variables by including concepts drawn from contemporary social psychological and deterrence-based research to enhance and extend the way that SLT variables have traditionally been examined. Differential reinforcement was conceptualised according to behavioural reinforcement principles (i.e., positive and negative reinforcement and punishment) and incorporated concepts of affective beliefs, anticipated regret, and deterrence-related concepts. Although implicit in descriptions of SLT, little research has, to date, made use of the broad range of reinforcement principles to understand the factors that encourage or inhibit behaviour. This approach has particular significance to road user behaviours in general because of the deterrence-based nature of many road safety countermeasures. The concept of self-identity was also included in the model and was found to be consistent with the definitions component of SLT.
A final theoretical contribution was the specification and testing of a full measurement model prior to model testing using structural equation modelling. This process is recommended in order to reduce measurement error by providing an examination of the psychometric properties of the data prior to full model testing. Despite calls for such work for a number of decades, the current work appears to be the only example of a full measurement model of SLT.
There were also a number of important practical implications that emerged from this program of research. Firstly, perceptions regarding speed enforcement tolerance thresholds were highlighted as a salient influence on driving speeds in both countries. The issue of enforcement tolerance levels generated considerable discussion among drivers in both countries, with Australian drivers reporting lower perceived tolerance levels than Chinese drivers. It was clear that many drivers used the concept of an enforcement tolerance in determining their driving speed, primarily with the desire to drive faster than the posted speed limit, yet remaining within a speed range that would preclude apprehension by police. The quantitative results from Studies 2 and 4 added support to these qualitative findings. Together, the findings supported previous research and suggested that a travel speed may not be seen as illegal until that speed reaches a level over the prescribed enforcement tolerance threshold. In other words, the enforcement tolerance appears to act as a ‘de facto’ speed limit, replacing the posted limit in the minds of some drivers.
The findings from the two studies conducted in China (Studies 2 and 4) further highlighted the link between perceived enforcement tolerances and a ‘de facto’ speed limit. Drivers openly discussed driving at speeds that were well above posted speed limits and some participants noted their preference for driving at speeds close to ‘50% above’ the posted limit. This preference appeared to be shaped by the perception that the same penalty would be imposed if apprehended, irrespective of what speed they travelling (at least up to 50% above the limit). Further research is required to determine whether the perceptions of Chinese drivers are mainly influenced by the Law of the People’s Republic of China or by operational practices. Together, the findings from both studies in China indicate that there may be scope to refine enforcement tolerance levels, as has happened in other jurisdictions internationally over time, in order to reduce speeding. Any attempts to do so would likely be assisted by the provision of information about the legitimacy and purpose of speed limits as well as risk factors associated with speeding because these issues were raised by Chinese participants in the qualitative research phase.
Another important practical implication of this research for speed management in China is the way in which penalties are determined. Chinese drivers described perceptions of unfairness and a lack of transparency in the enforcement system because they were unsure of the penalty that they would receive if apprehended. Steps to enhance the perceived certainty and consistency of the system to promote a more equitable approach to detection and punishment would appear to be welcomed by the general driving public and would be more consistent with the intended theoretical (deterrence) basis that underpins the current speed enforcement approach. The use of mandatory, fixed penalties may assist in this regard. In many countries, speeding attracts penalties that are dependent on the severity of the offence. In China, there may be safety benefits gained from the introduction of a similar graduated scale of speeding penalties and fixed penalties might also help to address the issue of uncertainty about penalties and related perceptions of unfairness. Such advancements would be in keeping with the principles of best practice for speed management as identified by the World Health Organisation.
Another practical implication relating to legal penalties, and applicable to both cultural contexts, relates to the issues of detection and punishment avoidance. These two concepts appeared to strongly influence speeding in the current samples. In Australia, detection avoidance strategies reported by participants generally involved activities that are not illegal (e.g., site learning and remaining watchful for police vehicles). The results from China were similar, although a greater range of strategies were reported. The most common strategy reported in both countries for avoiding detection when speeding was site learning, or familiarisation with speed camera locations. However, a range of illegal practices were also described by Chinese drivers (e.g., tampering with or removing vehicle registration plates so as to render the vehicle unidentifiable on camera and use of in-vehicle radar detectors). With regard to avoiding punishment when apprehended, a range of strategies were reported by drivers from both countries, although a greater range of strategies were reported by Chinese drivers. As the results of the current research indicated that detection avoidance was strongly associated with greater self-reported speeding in both samples, efforts to reduce avoidance opportunities are strongly recommended. The practice of randomly scheduling speed camera locations, as is current practice in Queensland, offers one way to minimise site learning. The findings of this research indicated that this practice should continue. However, they also indicated that additional strategies are needed to reduce opportunities to evade detection. The use of point-to-point speed detection (also known as secti
Social influences on drivers in China
China is one of Asia’s many rapidly-motorising nations and recent increases in private-vehicle ownership have been coupled with an escalation in novice drivers. Several pieces of road safety legislation have been introduced in recent decades in China. While managing the legal aspects of road use is important, social influences on driver behaviour may offer alternative avenues to alter behaviour, particularly in a culture where such factors carry high importance. This paper reports qualitative research with Beijing drivers to investigate social influence factors that have, to date, received little attention in the literature. Findings indicated that family members, friends, and driving instructors appear influential on driver behaviour and that some newly licensed drivers seek additional assistance to facilitate the transition from learning to drive in a controlled environment to driving on the road in complex conditions. Strategies to avoid detection and penalties for inappropriate road use were described, many of which involved the use of a third person. These findings indicate potential barriers to implementing effective traffic enforcement and highlight the importance of understanding culturally-specific social factors relating to driver behaviour
Evaluation of the Transfer of Heat from the Coil of the LHC Dipole Magnet to Helium II
During operation of the Large Hadron Collider at CERN, heat will be generated inside the coils of its superconducting magnets as a consequence of ramping of magnetic field, and of the interaction of lost beam particles with the magnet mass. Heat has to be transferred from the conductor into the He II coolant and removed from the magnet environment. During the LHC R&D stage, this transfer has been extensively studied on simulated coil segments at CEA/Saclay, and by analyzing dynamic behavior of short model magnets at CERN. Owing to the importance of efficient cooling for the design of future superconducting accelerator magnets, study of heat transfer has been restored at CERN and in frame of the Next European Dipole Collaboration. The article features two recently performed works: 1. Attempt to analyze archived high ramp rate quench data of 1-m-long LHC model dipole magnets of the 2nd generation. 2. Development of a method for direct measurement of heat transfer on segments of production LHC dipole magnet coils
Magnetresonanztomographie-gestützte Ablation von Vorhofflattern
Die Katheterablation ist ein etabliertes, kuratives Verfahren zur Behandlung von Patienten mit tachykarden Herzrhythmusstörungen und wird in der täglichen Routine der interventionellen Elektrophysiologen mit Hilfe von Durchleuchtungstechnik sowie nicht-fluororskopischen Navigationsverfahren durchgeführt. Hierbei erfahren Fluoroskopie-gestützte Verfahren insbesondere Limitierungen in der Darstellbarkeit arrhythmogener Zielgewebe und induzierter Gewebedefekte (Ablationsläsionen) und gehen teilweise mit einer sehr hohen Strahlenexposition für Patient und Untersucher einher. Die Magnetresonanztomographie (MRT) erlaubt die Darstellung von Gewebeveränderungen in einer röntgenstrahlenfreien Umgebung. Ziel der vorliegenden experimentellen und klinischen Untersuchungen war es, die Möglichkeiten der MRT-gestützten Ablationsbehandlung zu evaluieren.
In Teil 1 (experimentelle Untersuchung) dieser Arbeit wurden Verfahren zur Kathetervisualisierung, Elektrogrammableitung und Ablationsbehandlung bei neun Schweinen durchgeführt. Die Untersuchungsergebnisse zeigen, dass eine exakte und zuverlässige Kathetervisualisierung, die Ableitung von Elektrogrammen sowie die effektive und sichere Induktion von Ablationsläsionen innerhalb des MR-Tomographen umsetzbar sind. In Teil 2 (klinische Untersuchung) dieser Arbeit wurde die Durchführbarkeit und Behandlungssicherheit der MRT-gestützten Katheterablation von typischem, rechtsatrialem Vorhofflattern bei acht Patienten untersucht. Bei drei von acht Patienten konnte eine erfolgreiche Behandlung allein im MR-Tomographen erzielt werden. Bei vier Patienten war eine kombinierte Behandlung im MR-Tomographen und fluoroskopischen Elektrophysiologe-Labor (konventionelles EP-Labor) notwendig, um einen kompletten rechtsatrialen Isthmusblock zu induzieren. Bei einem Patienten trat innerhalb des MR-Tomographen eine bedeutsame Prozedur-assoziierte Komplikation auf (Katheterentrapment). Diese Komplikation konnte innerhalb eines konventionellen EP-Labors behoben werden.
Die Ergebnisse der vorliegenden experimentellen und klinischen Untersuchungen zeigen, dass MRT-gestützte Ablationsbehandlungen möglich und umsetzbar sind, es jedoch weiterer methodischer Verbesserungen und zusätzlicher Untersuchungen bedarf, um die klinische Anwendung der MRT-gestützten Katheterablation zu etablieren.:Inhaltsverzeichnis
Bibliographische Beschreibung 4
Abkürzungsverzeichnis 5
Abbildungsverzeichnis 7
Tabellenverzeichnis 7
1. Einführung 9
1.1. Katheterablation von Herzrhythmusstörungen 10
1.2. Vorhofflattern 12
1.2.1. Epidemiologie 13
1.2.2. Klinik und Komplikationen 14
1.2.3. Diagnostik und EKG-Kriterien 14
1.2.4. Behandlungsstrategien 16
1.1. Konventionelle Durchführung der Katheterablation mittels Fluoroskopie 18
1.1.1. Strahlenexposition 20
1.3. Bildgebung in der Elektrophysiologie 22
1.2. Magnetresonanztomographie 23
1.2.1. Grundlagen 23
1.2.2. Einsatz in der Kardiologie 24
1.3. Tracking 26
1.3.1. Passive Imaging 26
1.3.2. Active Tracking 27
1.4. Herausforderungen für interventionelles Arbeiten innerhalb der MRT-Umgebung 28
2. Aufgabenstellung 30
2.1. Teil 1: Experimentelle Untersuchung (Tiermodell) 31
2.2. Teil 2: Klinische Untersuchung (Humanstudie) 31
3. Material und Methoden 32
3.1. MRT-interventionelle Technologien 32
3.1.1. Elektrophysiologie-Arbeitsplatz und Katheter 32
3.1.2. Ablationskatheter und Verbindungskabel 33
3.1.3. Elektrophysiologischer Messplatz 34
3.1.4. Interventional MRI Suite (iSuite) 35
3.1.5. MRT-Scanner und Sequenzen 36
3.2. Teil 1: Experimentelle Untersuchung (Tiermodell) 38
3.2.1. Experimentelles Setting 38
3.3. Teil 2: Klinische Untersuchung (Humanstudie) 39
3.3.1. Patientendaten 39
3.4. Statistische Betrachtung 39
4. Ergebnisse 40
4.1. Teil 1: Experimentelle Untersuchung (Tiermodell) 40
4.1.1. Vorbereitung und prozedurale Parameter 40
4.1.2. Segmentierung der kardialen Anatomie und Rekonstruktion der 3D-Geometrie 41
4.1.3. Intubation des CS, Ableitung von Elektrogrammen und Durchführung von Stimulationsmanövern 43
4.1.4. Generierung einer Aktivierungsmap des rechten Vorhofs 46
4.1.5. Ablation des AV-Knotens 48
4.1.6. Postmortale Entnahme der Herzen und makroskopische Beurteilung der Ablationsläsionen..49
4.2. Teil 2: Klinische Untersuchung (Humanstudie) 50
4.2.1. Untersuchungsvorbereitungen 50
4.2.2. Segmentierung der kardialen Anatomie und Rekonstruktion der 3D-Geometrie 50
4.2.3. Katheterplatzierung, intrakardiale Elektrogramme und Stimulation 52
4.2.4. Ablation des rechtsatrialen Isthmus 53
4.2.5. Visualisierung der Ablationsläsion 55
4.2.6. Prozedurale Daten und Komplikationen 55
5. Diskussion 57
5.1. Zusammenfassung und kritische Würdigung der wesentlichen Untersuchungsergebnisse 57
5.2. Experimentelle und klinische Befunde zum Einsatz von MRT-Technologie in der Elektrophysiologie 59
5.3. 3D-Rekonstruktion und Katheternavigation 61
5.4. Katheterablation im MR-Tomographen 61
5.5. Interventions-MRT in der Elektrophysiologie: ein Ausblick 62
6. Zusammenfassung der Arbeit 63
7. Literaturverzeichnis 66
8. Anlagen 72
8.1. Erklärung über die eigenständige Abfassung der Arbeit 73
8.2. Lebenslauf 74
8.3. Publikationen 75
8.4. Danksagung 7
Kontrastmittelinduziertes Nierenversagen nach Koronarangiographie:eine prospektive kontrollierte klinische Studie an 213 Patienten
Das Thema des kontrastmittelinduzierten Nierenversagens (KIN) besitzt eine große Relevanz. In einer prospektiven, randomisierten Studie mit 213 Patienten mit Nierenfunktionseinschränkung untersuchten wir drei verschiedene Präventionsmöglichkeiten des KIN. Verglichen wurden erstens eine alleinige forcierte Diurese mit 500 ml 0,9%NaCl-Lösung + 500 ml einer 5%igen Glucoselösung jeweils vor und nach der Untersuchung, zweitens eine forcierte Diurese + einmalige Hämodialyse und drittens eine forcierte Diurese + tägliche Gabe von jeweils 2x600mg des Antioxidants Acetylcystein über 2 Tage. Insgesamt entwickelten 33 von 213 Patienten (15,5%) ein KIN, 11 von 76 (14,5%) in der Diurese-Gruppe, 15 von 71 (21,1%) in der Dialyse-Gruppe und 7 von 66 (10,6%) in der Acetylcystein-Gruppe. Alle Unterschiede zwischen den Therapiegruppen waren statistisch nicht signifikant
20% by 2020? Economy-wide impacts of energy efficiency improvement in Germany
The paper presents results of the implementation of an efficiency strategy in Germany until 2020 which is focused on cost-effective measures. The efficiency measures are calculated in bottom-up models and translated into a top-down macro-economic model. The comparison to a business as usual simulation shows some economy-wide rebound effects of about 17% of the overall energy savings. The analysis is limited to 2020. Given that an efficiency strategy is a long-term strategy, this puts the results on the rather conservative side. The results clearly show that improved energy efficiency results in a variety of positive effects on the economy and the environment. These range from reduced greenhouse gas emissions to improved competitiveness of firms and budget savings for consumers to economy wide impacts like additional employment and economic growth. Even the consideration of rebound effects did not change this picture significantly. Thus, exploiting the huge potential stemming from cost-effective efficiency measures should have high priority for the design of energy and climate policies.energy efficiency, bottom up scenario analysis, climate policy
Support and compliance with 20 mph speed limits in Great Britain
© 2015 Elsevier Ltd. All rights reserved. There are a number of challenges relating to both the support of and compliance with speed limits. The introduction of 20 mph limits in Great Britain is no exception: the recent rise in the deployment of these limits in urban settings has created a need to understand these issues in more depth. This paper reports a study undertaken by the authors that used a population wide survey of GB drivers to explore how support and compliance were interlinked. Whilst as expected many supporters said they would comply with the limits, and many opponents might not comply, more surprisingly it was also found that some supporters claimed not to comply, while some opponents of 20 mph limits were compliers. Explanations included the strong likelihood of strong moral adherence to not breaking laws amongst opponent-compliers, and self-enhancement bias amongst supporter-non-compliers. This paper explores the incidence of these effects and their implications in detail
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