Comparative advantage and the cross-section of business cycles

Business cycles are both less volatile and more synchronized with the world cycle in rich countries than in poor ones. We develop two alternative explanations based on the idea that comparative advantage causes rich countries to specialize in industries that use new technologies operated by skilled workers, while poor countries specialize in industries that use traditional technologies operated by unskilled workers. Since new technologies are difficult to imitate, the industries of rich countries enjoy more market power and face more inelastic product demands than those of poor countries. Since skilled workers are less likely to exit employment as a result of changes in economic conditions, industries in rich countries face more inelastic labour supplies than those of poor countries. We show that either asymmetry in industry characteristics can generate cross-country differences in business cycles that resemble those we observe in the data.Asymmetries, comparative advantage, labour skills, technology

Sensing and visualizing spatial relations of mobile devices

Location information can be used to enhance interaction with mobile devices. While many location systems require instrumentation of the environment, we present a system that allows devices to measure their spatial relations in a true peer-to-peer fashion. The system is based on custom sensor hardware implemented as USB dongle, and computes spatial relations in real-time. In extension of this system we propose a set of spatialized widgets for incorporation of spatial relations in the user interface. The use of these widgets is illustrated in a number of applications, showing how spatial relations can be employed to support and streamline interaction with mobile devices

A brief social-belonging intervention in the workplace: evidence from a field experiment

Brief interventions that strengthen an individual’s sense of social belonging have been shown to improve outcomes for members of underrepresented, marginalized groups in educational settings. This paper reports insights based on an attempt to apply this type of intervention in the technology sector. Adapting a social-belonging intervention from educational psychology, we implemented a quasi-random field experiment, spanning twelve months, with 506 newly hired engineers (24% female) in the R&D function of a west coast technology firm. We did not find a statistically significant effect of the treatment on a core attainment outcome—bonus relative to base salary—that exhibited a significant gender gap, with women receiving proportionally lower bonuses than men. We did not find anticipated gender gaps in promotion rates or social network centrality, and we also did not find a statistically significant effect of the treatment for women on these outcomes. Drawing on meaningful differences between educational versus workplace settings, we identify four theoretical moderators that might influence the efficacy of social-belonging interventions adapted from educational settings into the workplace. Finally, based on the limitations of our study design, we provide four recommendations that future researchers might adopt.Accepted manuscrip

Reading with Mobile Phone & Large Display

In this paper we compare performance and usability between three different device combinations: a) mobile phone b) touch screen c) mobile phone & screen. We show that mobile phone & screen has a better perform-ance than phone only. We also discuss some interaction issues when using a mobile phone with a large screen

Investigations on the flow over rotating smooth spheres and soccer balls

Die Wechselwirkung zwischen kugelförmigen Körpern und der sie umgebenden Strömung ist bei Ballsportarten von großer Bedeutung. Im Fußballsport werden Torschüsse und Freistöße häufig ohne oder mit wenig Rotation ausgeführt, um eine flatternde Flugbahn zu erhalten. In vielen Spielsituationen wird zudem der so genannte Magnuseffekt zur Erzeugung einer gekrümmten Flugkurve ausgenutzt. Ziel der vorliegenden Arbeit ist es, mit Hilfe einer Literaturstudie zunächst ein grundlegendes Verständnis der auftretenden Strömungsphänomene zu erhalten und aufzuzeigen, wo Forschungsbedarf besteht. Gleichzeitig wird herausgestellt, dass die verwendete Modellhalterung bei ein und demselben Experiment zur Kugelumströmung großen Einfluss auf die Ergebnisse ausübt. Bei der Konzeption der Windkanalversuchsstände dieser Arbeit lag das Hauptaugenmerk deshalb darauf, eine größtmögliche Reduktion der Interferenz zwischen der Umströmung der Modellhalterung und der Kugel- bzw. Ballumströmung mittels geeigneter konstruktiver Maßnahmen zu erreichen. Untersuchungen ohne Rotation zeigen, dass bei Fußbällen der kritische Reynolds-Zahl-Bereich verglichen mit glatten Kugeln zu deutlich niedrigeren Reynolds-Zahlen verschoben ist. Gleichzeitig treten in diesem kritischen Reynolds-Zahl-Bereich sehr hohe Auftriebs- und Seitenkräfte auf. Bei glatten Kugeln liegen im überkritischen Re- Bereich zeitlich gemittelte Auftriebs- und Seitenkräfte ungleich null vor, da der Nachlauf zu der strömungsparallelen Achse geneigt ist. Bei Fußbällen hängen im kritischen und überkritischen Re-Bereich Größe und Richtung der Kräfte quer zur Strömungsrichtung von der Ballausrichtung zur Anströmung ab. Die Untersuchungen mit Rotation zeigen: Die Messergebnisse der an den Polen angetriebenen glatten Kugeln und Modellfußbälle sind sehr stark durch den Einfluss der Aufhängung beeinflusst. Ergebnisse mit einer Aufhängung, welche die rotierenden Versuchskörper rückwärtig hält, weisen eine deutlich geringere Beeinflussung auf. Aerosol-Visualisierungen und Windkanalwaage-Messungen an der rotierenden Kugel zeigen, dass für Reynolds-Zahlen 125.000 < Re < 450.000 und Spinparameter basierend auf Drehfrequenzen f < 10 Hz überwiegend ein negativer Magnuseffekt vorliegt. Die gleichzeitig auftretenden hohen Seitenkräfte und Seitenkraft-Fluktuationen zeigen, dass der Magnuseffekt bei einer glatten Kugel im kritischen Re-Zahl-Bereich dreidimensional ausgeprägt ist. Bei einem Modellfußball zeigt sich eine generelle Verschiebung der Reynolds-Zahl-Bereiche zu geringeren Reynolds-Zahlen. Ein negativer Magnuseffekt tritt im Bereich 96.000 < Re < 248.000 auf, wobei die Seitenkräfte gering sind. Fußball-Flugkurvensimulationen ohne Rotation zeigen, dass Seiten- und Auftriebskräfte zwar zu kaum abweichenden Flugzeiten führen, jedoch eine große Streuung der Koordinatenpaare {y,z} in der Torebene verursachen. Der negative Magnuseffekt führt bei glatten Kugeln dazu, dass seitliche Abweichungen von einer geraden Flugbahn auftreten, die entgegengesetzt zu denjenigen bei Fußbällen sind.The interaction of spherical bodies with the flow surrounding them plays a very important role in ball aerodynamics. In soccer shots on goal and free kicks are often performed without or with little spin in order to generate a swerve from the expected trajectory, the so-called knuckling effect. A second strategy involves applying spin to the ball around an axis perpendicular to the flight direction, which generates a curved trajectory due to the Magnus force. In the present study a basic understanding of the flow phenomena observed is established. Furthermore it is pointed out where more research on sphere and ball aerodynamics is needed. Additionally it is made clear, that experimental results often vary to a great extent even if the boundary conditions are the same due to the experimental set-up. Thus, the conceptual design of the wind tunnel set-ups of the present work was to reduce the flow interference of the supporting device with the sphere or soccer ball. Investigations in the non-rotating state show that for soccer balls the critical Reynolds number range is shifted to considerably lower Reynolds numbers than for a smooth sphere. Simultaneously very high lateral forces are observed in this critical Reynolds number range. For a smooth sphere in the supercritical Reynolds number range, lateral forces are non-zero when averaged over an appropriate time interval. The reason is that the wake is inclined with respect to the flow axis. In the supercritical Reynolds number regime of a soccer ball the magnitude and direction of the lateral forces depend on the ball orientation relative to the approaching flow. The investigations in the rotating state show the following: The results obtained on a sphere driven by a shaft passed through the sphere center are influenced to a great extent by the flow interaction with the supporting device. When a rear mounted supporting device is used, the results are less affected. Aerosol visualizations and wind tunnel balance measurements show that for a rotating sphere mainly reverse Magnus effect occurs when the Reynolds number is in a range of 125.000 to 450.000 and the spin parameter is based on rotational frequencies lower than 10 [Hz]. Considerable lateral forces and lateral force fluctuations occurring simultaneously prove that the Magnus effect for a sphere in the critical Reynolds number range is three-dimensional. For a model of a soccer ball a general shift of the Reynolds number range to lower Reynolds numbers is observed. Reverse Magnus effect occurs in a Reynolds number range of 96.000 to 248.000 whereas lateral forces are low. Soccer ball trajectory simulations without spin show that lateral forces do not significantly change the flight time, but cause a scattering of the coordinates in the goal plane. The reverse Magnus effect obtained on smooth spheres leads to lateral deviations from a straight trajectory opposite to those observed for soccer balls

The Moderating Role of PBS in the Relationship Between Positive Expectancies and Alcohol-Related Negative Consequences

Hazardous drinking college students have become an increasingly focused upon group within alcohol research, especially considering the extent of negative consequences they experience. Recently, increased positive expectancies has been identified as an influential contributor to increased hazardous drinking and alcohol-related negative consequences. However, more comprehensive evaluation of the domains of positive expectancies (e.g., sociability, tension reduction, sexual enhancement, liquid courage) is warranted to ascertain which types are more salient in predicting hazardous drinking and alcohol-related negative consequences. Further, research has yet to explore how protective behavioral strategies (PBS) affect the strength of the associations between specific positive expectancies and alcohol-related negative consequences. Therefore, the goal of the present study was to investigate the moderating role of PBS in the relationship between the domains of positive expectancies and alcohol-related negative consequences in a sample of hazardous drinking college students. Using moderated multiple regression, significant positive associations were observed for liquid courage and sexual enhancement positive expectancies whereas an inverse association for PBS-Serious Harm Reduction (SHR) emerged. But, no moderating effects for PBS were found in any of the analyses. These results suggest that liquid courage and sexual enhancement positive expectancies may be more salient in predicting alcohol-related negative consequences. Clinical and empirical implication, limitations, and future research directions are discussed

The Mediating Effects of Drinking Refusal Self-Efficacy on the Associations between Alcohol Protective Behavioral Strategies and Alcohol Use Outcomes

Alcohol use continues to pose a serious public health problem at universities across the U.S., largely due to the extent of consumption and frequency of negative consequences experienced among college students. Alcohol protective behavioral strategies (PBS-A) are an empirically supported repertoire of safe drinking behaviors college students can use to monitor and control their alcohol consumption as well as limit harm while drinking. However, there remains a need to better understand how cognitive mechanisms, such as drinking refusal self-efficacy (DRSE), help explain college student safe alcohol use behaviors to enhance evidenced-based intervention and prevention efforts. Recently, studies that examined the moderating effect of DRSE on the associations among PBS and alcohol use outcomes demonstrated contradictory results. Therefore, the present study evaluated the mediating effects of DRSE broadly and its dimensions (i.e., social pressure DRSE, emotional relief DRSE, opportunistic relief DRSE) in the associations among PBS-A and its subtypes with alcohol use outcomes. Data were collected from a national sample of 380 traditional age (M = 22.50; SD = 1.82), full-time college students (51% male; 68% White, non-Hispanic) who completed an on-line survey about their safe and harmful alcohol use behaviors. Using path analysis, DRSE partially mediated all associations among PBS-A and all outcomes. Moreover, opportunistic relief DRSE mediated relationships between PBS-A and all three outcomes. Finally, all subtypes of DRSE fully mediated the relationship between serious harm reduction PBS-A and negative consequences. Altogether, these results suggest that DRSE may be an important cognitive variable to consider when evaluating PBS-A use and their relationships with alcohol outcomes among college students. Study limitations as well as clinical and research implications will be discussed

Enhancing Usability Evaluation of Web-Based Geographic Information Systems (WebGIS) with Visual Analytics

Many websites nowadays incorporate geospatial data that users interact with, for example, to filter search results or compare alternatives. These web-based geographic information systems (WebGIS) pose new challenges for usability evaluations as both the interaction with classic interface elements and with map-based visualizations have to be analyzed to understand user behavior. This paper proposes a new scalable approach that applies visual analytics to logged interaction data with WebGIS, which facilitates the interactive exploration and analysis of user behavior. In order to evaluate our approach, we implemented it as a toolkit that can be easily integrated into existing WebGIS. We then deployed the toolkit in a user study (N=60) with a realistic WebGIS and analyzed users\u27 interaction in a second study with usability experts (N=7). Our results indicate that the proposed approach is practically feasible, easy to integrate into existing systems, and facilitates insights into the usability of WebGIS

Clearing and Cultivating Carceral Space: A historical geography of Stewart Detention Center

Stewart Detention Center (SDC) is a private immigrant detention center in Lumpkin, Georgia, 150 miles southwest of Atlanta and is one of the largest immigrant detention centers in the country. I conduct a historical geography of the space in and around Stewart Detention Center to better understand SDC as a continuation of colonial and racial territorializations integral to the nation-state and extending from the 18th century to the present. I analyze archival documentation of the material manifestations of carceral territorialization, including a 19th century map and photographs of a series of erosion gullies fifteen miles from SDC. Finally, an intimate geography of the body in detention brings this analysis into the contemporary carceral space. Tracking the spatial practices of white supremacist land-body violence that accrue over time will flesh out contemporary understandings of prisons and detention centers as not timeless institutions but contemporary iterations within a historical constellation of carceral space