What does a motorcyclist look at while driving at urban arterials?

To design adequate measures for enhancing riders' safety, a necessary first step is to understand the riders' visual scanning strategies under different traffic conditions. This paper presents the preliminary analysis of eye tracking data collected by three riders in the Athens metropolitan area, riding along urban arterial motorways and along an undivided urban road. Apart from the fixation duration and location, the fixated road elements and specific objects were annotated and analysed. The mean duration of fixations was found to be higher on urban roads than on motorways for all traffic densities. Riding in the condition of restricted flow seems to be more demanding for the riders, since the mean duration of fixations was higher in restricted flow than in free or congested flow on motorway and also higher than in free flow on urban road. The riders' fixation locations differed between motorway and urban road, especially in the vertical plane. The analysis of fixated road elements and specific objects indicates the specific points of interest of riders in each case. Although results should be validated with data from more riders, they provide hints on direction of future research efforts to enhance riders' safety in urban environments.     

Naturalistic observation of drivers' interactions while overtaking on an undivided road

Current models of driving behavior and designs of driver support systems are not taking adequately into account the interactions between drivers. Although a driver's intended maneuver may not be physically possible at a specific time point, it may still be safely executed if the driver's intention is successfully communicated to and interpreted by another driver, who alters the own future trajectory so as to enable the maneuver execution. This paper presents some empirical findings relevant to communicative and cooperative interactions between drivers along naturalistic overtaking maneuvers on an undivided road. The cues used by drivers to interpret other drivers' intention and the drivers' interactions were extracted through video observations of the maneuvers together with the frequency of such interactions per level of traffic risk. The findings show that drivers use formal and informal cues to anticipate other drivers' intention. A significant percentage of maneuvers were performed after facilitation by other drivers. Future studies should focus on this phenomenon while future models of driving behavior should incorporate communicative and cooperative interactions among drivers, so as to design adequate cooperative support systems to enhance road safety.     

Educational needs of inpatients with severe & persistent mental illness: a partial replication

Although a great deal has been written about the importance of patient education, few replications of past research have been conducted to increase clinicians' confidence in the conclusions of previous studies. This is especially true of studies conducted in clinical settings where findings may or may not be generalizable to other institutions. This partial replication study tested whether previous findings about patient education in an outpatient setting were applicable to an inpatient setting using a modified version of the instrument. A 1998 study published in this journal suggested that differences may exist between the perceived health education needs of outpatients and their health care providers. In this partial replication, we examined the differences between the educational needs of inpatients and those perceived by their attending nurses. As in the original study, we found discrepancies between patients' actual needs and nurses' perceptions of those needs, supporting the importance of assessing patients' health educational needs in the treatment planning process.     

Two Population-Environment Regimes in the Great Plains of the United States, 1930–1990

This paper analyzes factors that affect net migration rates in counties in the U.S. Great Plains between 1930 and 1990, emphasizing the roles of weather (especially drought), environmental amenities, employment, and population, making use of a rich county-level data set. Using a pooled time series model the paper shows that environment is important in population processes, with weather and agricultural change more important in the 1930s and 1940s, and environmental amenities more important in later time periods. The paper provides important insights into how environmental impacts on migration might change over time, and how those changes might be measured.     

The concept of contradiction in ergonomics practice

The present communication deals with the methodology of the ergonomics field intervention process. It proposes an operationalized version of work analysis in terms of contradictions. The aim is to demonstrate that such a dialectic tool and method of representation may assist the ergonomist to frame the essence of a work activity in practical terms, swiftly and in a manner that preserves its multifaceted unity. The proposed method is inspired by two theoretical constructs (i) contradiction as used in Cultural Historical Activity Theory and (ii) regulation, as developed and used by the francophone tradition of ergonomics of activity. Two brief examples of its use are presented and a discussion is made on further developments and possible pitfalls.     

Efficient Computation of Reduced Regression Models

We consider settings where it is of interest to fit and assess regression submodels that arise as various explanatory variables are excluded from a larger regression model. The larger model is referred to as the full model; the submodels are the reduced models. We show that a computationally efficient approximation to the regression estimates under any reduced model can be obtained from a simple weighted least squares (WLS) approach based on the estimated regression parameters and covariance matrix from the full model. This WLS approach can be considered an extension to unbiased estimating equations of a first-order Taylor series approach proposed by Lawless and Singhal. Using data from the 2010 Nationwide Inpatient Sample (NIS), a 20% weighted, stratified, cluster sample of approximately 8 million hospital stays from approximately 1000 hospitals, we illustrate the WLS approach when fitting interval censored regression models to estimate the effect of type of surgery (robotic versus nonrobotic surgery) on hospital length-of-stay while adjusting for three sets of covariates: patient-level characteristics, hospital characteristics, and zip-code level characteristics. Ordinarily, standard fitting of the reduced models to the NIS data takes approximately 10 hours; using the proposed WLS approach, the reduced models take seconds to fit.     

Better Homes and Families: Housing Markets and Young Couple Stability in Sweden

I model the relationship between aspects of the housing market influenced by housing policy and couple stability for cohabiting couples in Sweden. Using data on 3,851 cohabiting couples obtained from the Swedish Family Survey of 1992, I examine the effects of housing market characteristics on couple outcomes. I focus on three housing variables, including the affordability of housing, the availability of detached housing, and the profitability of ownership. I link these variables to the transitions from cohabitation to marriage or separation in Sweden. Policy relevant aspects of the housing market are shown to have significant effects on the stability of couples in Sweden. Greater affordability increases couple stability. Intriguingly, greater availability of detached housing significantly weakens couple stability.     

Risk aversion and religion

We use a dataset for a demographically representative sample of the Dutch population that contains a revealed preference risk attitude measure, as well as detailed information about participants’ religious background, to study three issues. First, we find strong confirmatory evidence that more religious people, as measured by church membership or attendance, are more risk averse with regard to financial risks. Second, we obtain some evidence that Protestants are more risk averse than Catholics in such tasks. Third, our data suggest that the link between risk aversion and religion is driven by social aspects of church membership, rather than by religious beliefs themselves.     

Local Economic Opportunity and the Competing Risks of Internal and U.S. Migration in Zacatecas,Mexico1

This article uses a competing risks model to examine the effects of origin economic conditions on the probability of temporary U.S. and internal labor migration in the Mexican state of Zacatecas. We measure origin economic conditions with municipal‐level indices of employment and small‐scale investment opportunities that we constructed from population and economic census data. The results of our analysis demonstrate the important influence of local employment and investment opportunities on migration outcomes. Controlling for the prior municipal rate of U.S. return migration and other factors, positive opportunities for small‐scale investment are associated with a higher risk of temporary migration to the United States. This result is consistent with investment oriented migration predicted by the new economics of labor migration theory. We also find comparable social network effects for both internal and U.S. migration. Having social ties to active migrants of one type (U.S. or internal), encourages migration of the same type and discourages migration of the other type.     

A room of one’s own or room enough for two? Access to housing and new household formation in Sweden, 1968–1992

Familistic and individualistic theories both provide explanations for recent declines in family household formation. Securing access to housing plays a key role in new household formation for both these theories. Familistic theories hypothesize a positive relationship between access to housing and new family household formation. Individualistic theories hypothesize a positive relationship between access to housing and nonfamily household formation. Here I test these hypotheses in Sweden by modeling leaving home for family and nonfamily household formation using the Swedish Family Survey and supplemental housing data. I find significant support for the familistic notion that greater access to housing increases the likelihood of family household formation. I fail to find support for the individualistic theory.