It is estimated that 50,000 individuals become newly infected with human immunodeficiency virus (HIV) every year in the United States. HIV is a lentivirus that is primarily spread through sexual contact. If left untreated, this viral infection can lead to decreased CD4+ T cells, increased susceptibility to opportunistic infections, and eventually progression to acquired immunodeficiency syndrome (AIDS) and death. HIV viral loads can be decreased to undetectable levels with the use of combination antiretroviral therapy (cART). In 2012 the Food and Drug Administration approved cART therapy, Truvada (tenofovir/emtricitabine), for safe use as pre-exposure prophylaxis (PrEP). When detectable levels of drug are present in the blood stream of patients, there is up to a 92% relative risk reduction in HIV infection compared to placebo. The implementation of PrEP has the potential to decrease the incidence of new HIV infections in at-risk populations worldwide. Because PrEP treatment is relatively new (2012), there are many barriers to administration to patients. Increased risky sexual behavior, known as risk compensation, is one of the concerns providers cite as a reason against prescribing PrEP. Most publications on PrEP have described randomized controlled trials that focused on safety, efficacy, and to a lesser extent, risk compensation behaviors. Now that Truvada is widely available, researchers are starting to elucidate patients’ sexual habits while using PrEP in the outpatient settings. However, there is a need for more longitudinal research regarding the behaviors of individuals using PrEP, specifically to determine how often risk compensation occurs and under what conditions. This study will initiate a PrEP clinic at Boston Medical Center and run a 3 year, open-label randomized controlled trial of eligible men who have sex with men (MSM) patients, who either start PrEP immediately or are delayed by one year. It is hypothesized that condom usage will decrease among immediate PrEP participants compared to the delayed participants. The study aims to determine if risk compensation occurs in these patients by following condom usage, development of sexually transmitted infections, number of sexual partners, and number/type of sexual encounter. Secondary outcomes will include measurements of medication adherence and number of HIV-seroconverters. These data will be collected through surveys and laboratory testing. The resulting information will help medical professionals better understand the risks and benefits of PrEP and also how to implement it most effectively in the fight to reduce the worldwide HIV burden.

Abstract This study aims to show how the company management reasons when it comes to underpricing IPO´s. In the market climate of today more and more companies are listed on the stock exchange and the business press is constantly reporting about highly increasing stock values. This validates the current interest of the subject and the importance of finding the underlying reasons of the decisions made. Interviews have been conducted with three newly listed companies, who all had a high initial price increase, and with their underwriters. Thanks to the underwriters we have been able to triangulate the empirical data provided by the companies. Therefore we could also put the motives and reasoning’s of the company management into words. What the study has shown is that founders have the ambition to develop the company further, rather than to conduct the IPO in order to cash out from the business as suggested in the theories. The choices they make in the form of lock up agreements, pre-IPO call options and rights offerings will signal long-term commitment and market interest regarding the company. This can build an amount of trust towards the investors and the demand for risk compensation in the shape of underpricing will be lowered. Committed investors will establish consensus in the market and others will follow in their footsteps, creating an information cascade. As a consequence, IPOs rarely are moderately subscribed but rather very over- or undersubscribed. Small price changes can therefore make the difference between a successful and an unsuccessful IPO. Because of this, the company is forced to underprice in order to create more attractive circumstances even though the market climate is good. / Sammanfattning Studiens mål är att belysa hur företagsledningar strategiskt resonerar om underprissättning vid börsintroduktion. I rådande marknadsklimat noteras fler och fler bolag där branschpress ständigt rapporterar om kraftigt stigande initiala aktiekurser. Detta gör ämnet aktuellt och intressant att undersöka bakomliggande faktorer kring. Intervjuer har gjorts med tre nyligen börsintroducerade bolag som haft en kraftig initial kursstigning, samt deras finansiella rådgivare. Tack vare den finansiella rådgivaren har vi kunnat triangulera empirin från bolagen och därmed kunnat sätta ord på bakomliggande resonemang och motiv till underprissättningen. Det studien visat är att företagsledningen har ambitionen att driva bolaget vidare mot tillväxt snarare än att sälja ut till marknaden för snabb avkastnings skull, vilket hävdats i teorier. Besluten dessa fattar i form av lock up-avtal, teckningsoptioner och teckningsförbindelser kommer leda till signaler om långsiktighet och intresse kring bolaget. På så vis kan ett förtroendekapital byggas mot investerarna och kompensationskrav i form av underprissättning minskar från dessa. Engagerade investerare kommer skapa konsensus på marknaden och övriga kommer följa i deras steg vilket skapar en informationskaskad. På grund av detta blir sällan börsintroduktioner medeltecknade utan snarare mycket över- eller undertecknade. Marginella prisändringar kan därför göra skillnaden mellan en lyckad och misslyckad börsintroduktion. Detta gör att bolaget tvingas skapa mer attraktiva förhållanden för investerarna genom underprissättning trots ett gynnsamt börsklimat.

Problem Bicycle volumes are increasing in many regions worldwide leading to higher relevance of an in-depth understanding of bicyclist safety mechanisms. Detailed studies on bicyclist safety that consider exposure and distinguish by intersection category and crash types are missing for urban signalised intersections which are of particular relevance for bicyclist safety. Method Based on a comprehensive dataset of motorist and bicyclist volumes and infrastructure characteristics for a sample of 269 signalised intersections in two German cities, we analyse in a top-down approach first bicycle crashes of all types and second bicycle crashes by type including turning, right-of-way and loss-of-control. A combination of descriptive statistics and Accident Prediction Models (APM) are applied in terms of analysis methods. Results Bicycle volumes are relevant for all types of intersections and crashes whereas the effect of motor vehicle volumes differ between these different applications. The separation of bicyclists from motor vehicles in time and space increases their safety but also leads to behavioural adaption and risk compensation. The likelihood of right-ofway crashes even increases with more separation in the signalling scheme. The main predictor for loss-of-control crashes in terms of infrastructure are tram tracks. Summary This study provides insights on relevant determinants of bicycle crashes at urban signalised intersections at several levels of detail. Exposure variables as well as the physical separation of bicyclists from motor vehicles show consistent effects on bicycle crash numbers whereas the effects of signalling differ between crash types. Practical Applications The different types of intersections and crashes follow each specific mechanisms of bicyclist safety. The separation of bicyclists and motorists in time and space are paramount at intersections with high bicycle volumes. Risk compensation such as red light running becomes more important as intersections get smaller and motor vehicle volumes decrease.

The aim of this study was to investigate different standards of bidirectional bike lanes and investigate if they provide enough space for the needs of cyclists. A method was developed for evaluating cyclists’ behaviour using the theory of risk homeostasis and two risk-factors; speed and sideways position. An experimental design was also constructed and the results from the subsequent experiment implies that the two chosen risk markers could be useful in future studies relating to the design of bicycle infrastructure. A significant difference in the positioning of cyclists was found on different bike lane widths. The risk markers for sideways position show significant results at bidirectional bike lane widths below 2.4 meters. At such widths, cyclists seem to actively position themselves closer to the curb in the presence of oncoming cyclists. This is interpreted as a risk compensation which indicates that cyclists are not completely comfortable on that standard of bike lane. A conclusion would be to view bidirectional bike lanes at 2.4 meters width on flat surfaces, with adequate safety-zones beside the bike lanes, as a good standard for regular cyclists in many situations. More widening is not believed to provide major additional experienced safety or passability until the width allow for safe overtaking in the presence of oncoming cyclists. / Syftet med denna studie var att undersöka olika standarder av cykelbanor och se om de tillgodoser cyklisternas utrymmesbehov. En metod utvecklades för att utvärdera cyklisters beteende på olika standarder av dubbelriktade cykelbanor med hjälp av riskhomeostasteorin och två riskmarkörer; sidledsposition och hastighet. En experimentdesign utvecklades och experimentet genomfördes. Resultaten tyder på att metoden fungerar och kan vara till nytta i framtida studier gällande cyklisters behov, relaterat till designen av cykelinfrastruktur. Resultaten visar att cyklisterna placerar sig längre från kanten på cykelbanan ju bredare den är. En statistiskt signifikant skillnad i sidledsposition uppmättes också vid möten av andra cyklister när bredden på cykelbanan sjönk till under 2,4 meter. Vid dessa bredder placerade sig cyklisterna aktivt närmare kanten vid möten. Resultatet tolkas som en form av riskkompensation och indikerar att cyklisterna inte är helt trygga på cykelbanor av den bredden. Slutsatsen blir att vi kan betrakta 2,4 meter breda, dubbelriktade cykelbanor på horisontella ytor med tillräckliga säkerhetsavstånd till hinder vid sidan av cykelbanan som en god standard för många förhållanden. Ytterligare breddning tordes inte ge några större upplevda säkerhets- eller framkomlighetsfördelar förrän bredden tillåter säkra omkörningar även vid möten.

HIV infection is a significant public health concern, particularly among young men who have sex with men (YMSM). Pre-exposure prophylaxis (PrEP) is highly effective in preventing HIV infection among YMSM when taken as prescribed. However, there may be unintended behavioral consequences associated with PrEP initiation, with previous studies finding associations between PrEP use and increased sexual risk behaviors such as condomless anal sex (CAS). Further, problematic alcohol use, to which YMSM are particularly vulnerable, may also play a role in increasing sexual risk as engaging in sexual behaviors while under the influence of alcohol has been associated with CAS and other sexual risk behaviors. Previous literature has proposed risk compensation theory as a basis for this change in sexual risk behaviors following PrEP initiation. However, results have been mixed, and fewer studies have examined risk compensation specifically among YMSM or explored the role of alcohol-related sexual behaviors in this relationship. The present study aims to examine risk compensation theory as a mechanism for the relationship between PrEP initiation and alcohol-related sexual behaviors among YMSM. We hypothesized that the trajectory of PrEP initiation would be positively associated with alcohol-related sexual behaviors across 18 months. Consistent with hypothesis, a combined latent difference score and latent trajectory model revealed a positive association between PrEP initiation and alcohol-related sexual behaviors between baseline and 18-month follow-up in a sample of YMSM. These results are consistent with previous research identifying a high-risk period following PrEP initiation among an already vulnerable group (YMSM), with implications for risk assessment and interventions targeting alcohol-related sexual behaviors among YMSM. This study also highlights the role of alcohol use in increasing sexual risk following PrEP initiation. Findings may aid in reducing adverse sexual outcomes among YMSM who initiate PrEP and ultimately contribute to the minimization of sexual health disparities among YMSM.

On-the-job injuries that occur even after implementing safety interventions highlight the need for identifying the limitations in them and for making future safety interventions and technological advances more effective. One possible reason for this lower-than-expected-safety returns is the latent side-effect of safety interventions, known as risk compensation. This dissertation aimed to provide empirical evidence and theoretical considerations of risk compensation effect in the construction industry. Accordingly, a multi-sensor immersive mixed-reality environment consists of a virtual projection of the environment and passive haptics of a roof was developed to study risk compensation among residential roofers. Simulating height, environmental factors (wind and sound), passive haptic, and virtual falls stimulated sufficient Sense of Presence to trigger subjects' behavioral changes while installing shingles on a 27-degree sloped roof under three levels of safety interventions (i.e., with no fall-safety intervention, with an injury-reducing fall-safety intervention—i.e., fall-arrest system—and with an injury-preventing fall-safety intervention— i.e., a fall-arrest system and a guardrail). The baseline demographic, psychographic, and cognitive measures combined with real-time tracking and wearable sensors provided an opportunity to track the worker's motions, localize his/her position, obtain real-time musculoskeletal data, and monitor the his/her behavioral and physiological responses. The collected data is then translated into information about the risk perception and risk-taking behavior of the worker. The results yielded unequivocal evidence of risk compensation—the lower perceived risk associated with the situation (lower levels of stress) and the false sense of security among roofers when they were provided with safety interventions apparently encouraged them to be less cautious by leaning over the edge, stepping closer to the roof edge, spending more time exposing themselves to fall risk, over-relying on the safety equipment through different facing directions and choices of posture stability. As a result, they also experienced more near-misses (close calls). This behavioral adaptation was more pronounced when they were provided with an injury-preventing safety intervention (e.g., guardrail). The findings also suggested that the productivity and safety benefits of safety interventions can be negated due to risk compensation, which identifies vital information for the construction-safety community to consider during the design and implementation of more effective safety interventions and technological advances. Roofers with high risk tolerance and sensation seekers were identified as high-risk groups who are more likely to be involved in risk-compensatory behaviors; various behavioral interventions are suggested in this dissertation to counteract excessive risk-taking and to reduce risk compensation. The findings of this study shed light on the question of why injury rates have remained at worrisome levels despite advances in protective measures and interventions. In the long-term, a better understanding of risk compensation will translate into fundamental knowledge about how the construction industry should approach and maintain controls after safety interventions. / Doctor of Philosophy / While researchers have dispensed considerable efforts to reduce the risk of occupational injuries by implementing safety interventions, the large number of safety incidents occurring each year in the construction industry. It is hypothesized that the latent effect of safety interventions, known as risk compensation, might be a possible reason why many of the safety interventions and technological advances have not fully achieved their safety objectives. This dissertation aimed to empirically examine the changes in workers' productivity, risk perception, risk-taking behaviors as a function of different safety interventions in place. To study this within a risk-free setting, an immersive mixed-reality environment simulating roofing task was developed. Then, the reactionary behavioral responses of participants were monitored using real-time tracking sensors and qualitative sources of data while they were completing a roofing task under three counterbalanced levels of safety interventions (i.e., with no fall-safety intervention, with an injury-reducing fall-safety intervention—i.e., fall-arrest system—and with an injury-preventing fall-safety intervention— i.e., a fall-arrest system and a guardrail). The findings indicated that the reduced perceived risk and the desire for increased productivity may skew risk analysis and strongly bias workers toward presuming invulnerability when safety interventions are in place. According to risk compensation theory, workers' risk tolerance and perceptions of risk influence their risk-taking behavior—as the perceived risk associated with the situation decreases, individuals take more risks to achieve a level of risk they can comfortably tolerate. Therefore, the workers might become less cautious by leaning over the edge, stepping closer to the roof edge, spending more time exposing themselves to fall risk, over-relying on the safety equipment through different facing directions and choices of posture stability. This result does not necessarily imply the safety innovations are completely ineffective, but rather demonstrates dangers users face when they misperceive the effectiveness of a safety intervention. Furthermore, roofers with high risk tolerance and a high sensation-seeking disposition were identified as high-risk groups who are more likely to be involved in risk-compensatory behaviors. This research represented a substantive departure from the status quo by proposing novel pathways for proactive incident prevention due to risk compensation in the construction industry. The contribution of this study is especially significant because a better understanding of risk compensation will translate into fundamental knowledge about how the construction industry should approach and maintain controls after safety interventions.

Med fler än en miljon omkomna i trafikolyckor världen över varje år är trafiksäkerhet ett ständigt aktuellt område. Studier på deprimerade patienter har visat att negativ sinnesstämning medför försämrad körförmåga. Dessa effekter är i hög grad outforskade och det är därför viktigt att undersöka om de förekommer även vid en mildare grad av nedstämdhet, så kallad dysfori, vilket i så fall skulle innebära att negativ sinnesstämning i likhet med trötthet och alkoholpåverkan utgör en allvarlig trafikfara. För att bättre förstå hur sinnesstämning påverkar körförmåga är det dock också relevant att undersöka om dysfori kan bidra till riskkompensation, det fenomen som inträffar när människor kompenserar för säkerhetsförändringar genom ett förändrat riskbeteende. I denna uppsats beskrivs en del av en körsimulatorstudie kring dysfori och bilkörning, där syftet var att undersöka om dysfori kan vara en orsak till riskkompensation. 15 studenter vid Linköpings universitet delades upp i en testgrupp med dysforiska försöksdeltagare (N = 5) och en kontrollgrupp (N = 10) med hjälp av Major Depression Inventory, ett instrument för att diagnostisera depression. Dessa fick sedan genomföra en körning i simulatorn Desktop T&D där time headway, time to collision, genomsnittshastighet och antal omkörningar mättes för de olika grupperna för att undersöka förekomsten av riskkompensation. Resultatet visade att inga signifikanta skillnader kunde observeras för något av måtten. Riskkompensation har i många studier visat sig vara ett komplext fenomen att undersöka och ett flertal metodologiska problem förelåg, särskilt på grund av svårigheten att mäta risk i en simulator med god validitet. Det är dock viktigt att fortsatta undersökningar görs för att bättre förstå riskkompensation, samt att fenomenet beaktas som en tänkbar inverkande faktor i framtida studier av körförmåga.

Indiana University-Purdue University Indianapolis (IUPUI) / Human papillomavirus (HPV) infection results in serious health issues including cervical, anal, vulvar, penile and oropharyngeal cancers. There are three vaccines against HPV but vaccination rates in the United States remain low. One barrier to uptake is a concern that individuals who are vaccinated may increase their risky sexual behaviors or decrease their use of cervical cancer screenings, an adjustment in perceived level of risk for HPV that can be studied using risk compensation theory. Methods Three distinct studies examined risk compensation after HPV vaccination. A systematic review examined literature from January 1, 2008-June 30, 2015, using three databases. A qualitative study using semi-structured interviews of 22 healthcare providers that assessed their beliefs regarding sexual disinhibition and cervical cancer screening following vaccination. A cross-sectional survey that assessed cervical cancer screening practices, awareness and comfort with recommendations, and knowledge regarding the purpose of a Papanicolaou (Pap) test. Results Twenty articles were included in the systematic review. None of the studies of sexual behaviors and/or biological outcomes found evidence of riskier behaviors after HPV vaccination. Instead, the studies found vaccinated individuals were less likely to report risky sexual behaviors, sexually transmitted infections (STIs), and pregnancy. Qualitative interviews found no healthcare providers believed the HPV vaccine would result in increased risky sexual behavior or decreased cervical cancer screening, and these concerns would not influence their vaccination recommendations. The survey included 291 women 21-35 years old; 62% were non-Hispanic black, 84% had a Pap test in the last three years, and 33% had at least one HPV vaccine. Logistic regression showed that vaccinated women did not have greater odds of having a Pap test in the past three years (OR=1.32; 95% CI=0.66-2.65; p=0.427). However, this odds ratio was significant when controlling for age and race (AOR=3.06; 95% CI=1.37-6.83; p=0.006). Conclusion These studies found no evidence of increased risky sexual behaviors or decreased cervical cancer screening rates after HPV vaccination. Furthermore, vaccinated women showed less evidence of risk compensation. These results should alleviate concerns about administering the HPV vaccination among parents and providers.