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Despite burgeoning evidence for the effectiveness of intergroup contact on prejudice reduction, relatively less is known about how much individuals’ internal control and active choice is involved in the formation of intergroup contact. Through four correlational studies (Ntotal = 1043, Study 1 in Cyprus and Studies 2‐4 in Turkey), we investigated the construct of ‘contact volition’ ‐ the extent to which one engages in intergroup contact deliberately. Studies 1‐3 showed that intergroup contact perceived as primarily intentional and pursued by the active choice of the self (volitional contact) was associated with greater intimacy and positivity and thereby more positive attitudes, compared to contact that is primarily based on external/situational conditions (contingent contact). Study 4 showed that contact quantity was associated with more positive attitudes and behavioral tendencies through greater intimacy and positivity, only when contact was volitional. Findings contribute to the recently emerging research literature on motivated contact behavior that can help maximize the effectiveness of contact.

Object of the study was the variability of social behavior and organization in female guinea pigs as a function of the presence of a male. Four groups of 8 females were observed. Two of these groups were without a male, the other two had a sexually experienced, sterilized male. All females were about 20 d old at the beginning of the study. In the groups without a male the females formed clear and stable dominance relationships resulting in a linear rank order. The frequency of agonistic behavior was higher compared to the other groups. Some of these females displayed male-like courtship behavior. Among the females in the groups with a male only the alpha and omega positions were stable, while the dominance relations between the other females remained unstable. These females directed about 40–50 % of their contact behavior towards the male. In relation to the presence or absence of a male the females differed in their social orientation: those who lived with a male were strongly orientated towards it, those living without a male were strongly oriented towards each other. The hypothesis is put forward, that the females in the two situations differed in their motivational states. For the females living with a male this animal was a stable point of social reference, while for the females living without a male their stable dominance structure — with more agonistic behavior — was the most important stabilizing factor.

A major function of contact calls in nonhuman primates is to maintain spatial cohesion among individuals in a group. The risks of spatial/visual separation from the group are likely to affect auditory contact behavior, in particular by increasing the call rate. We tested whether the risk of separation influences coo call emission by investigating the variation in call rate among behavioral contexts in two wild populations of Japanese macaques (Macaca fuscata). We focused on caller activity and the degree of visibility within the habitat as primary potential factors mediating call rate. We first estimated the habitat visibility of the two research sites at Yakushima Island (YK) and Kinkazan Island (KZ), Japan. The habitat visibility of YK was significantly more restricted than that of KZ. We then compared the call rate of 20 adult and 12 juvenile female macaques between the two wild populations to examine the potential effects of environmental differences. Both populations had a lower call rate during grooming than during feeding and moving, which are behaviors associated to higher interindividual distances. The call rate of YK adult females was significantly greater than that of both juveniles and KZ adult females, independently of activity. The call rate increased as macaques matured in the YK population, but not in the KZ population, suggesting that different developmental processes involved in contact calling of the two populations. Our findings suggest that separation risk influences call rate, and also imply a possibility of social influence that social structure change effects on the call rates. Am. J. Primatol. 70:1055–1063, 2008. © 2008 Wiley-Liss, Inc.

The Au/n-ZnO contact behavior was investigated as a function of hydrogen peroxide pre-treatment of the ZnO sample by current-voltage (IV) measurement. The change from non-rectifying to rectifying performance upon etching was discussed in connection with sample characterization by positron annihilation spectroscopy (PAS), Auger electron spectroscopy (AES) and scanning electron microscopy (SEM). It was concluded that the gain of the rectifying property was properly associated with the formation of a defective interfacial region at the Au/n-ZnO contact. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

A variety of signals are employed by animals to establish, mediate and advertise social bonds. Gentle contact behaviors, such as grooming in primates, are an important class of affiliative signals that may provide direct benefits (e.g. stress reduction, parasite removal) in addition to their signal information. Unlike other kinds of signals (e.g. male displays) examples of affiliative contact behaviors restricted to one sex are rare. Here we describe a strongly sex-biased affiliative behavior ‘contact swimming’, in female bottlenose dolphins in Shark Bay, Western Australia. Females were more likely to be observed contact swimming than males and the presence of males likely influenced this behavior. This is surprising given that female relationships have been characterized as weak. Female dolphins are sometimes herded and harassed by males and contact swimming occurs most often between females in malebiased groups. Contact swimming may serve as a signal of cooperation between females. Possible direct benefits include stress reduction and assisted locomotion.

In an effort to prevent degeneration of articular cartilage associated with meniscectomies, both meniscal allografts and synthetic replacements have been studied. A number of biomechanical criteria may be important for a meniscal replacement to restore normal tibiofemoral contact pressure in the knee joint and hence be clinically successful. One of these criteria is geometric similarity. The objectives of the current study were to: determine the sensitivity of the contact variables of the tibial plateau to the transverse depth and width of both the lateral and medial menisci; determine the sensitivity of the contact variables of the tibial plateau to the cross-sectional width and height of the lateral and medial menisci; and determine the tolerances on each of the four parameters for both menisci. To satisfy these objectives, a previously developed finite element model of the tibiofemoral joint was used to compute the contact pressure distribution on the tibial plateau. The effect of the above-mentioned geometric parameters on the contact behavior was studied by perturbing the finite element model. Results showed that the contact variables are similarly sensitive to both the transverse and cross-sectional parameters of the menisci. Additionally the medial meniscal parameters have a greater effect on the contact variables than do the lateral meniscal parameters. Finally, less than a 0.5 mm change in the medial meniscal height and greater than a 1 mm change in the lateral meniscal height could be tolerated before the relative difference in the contact variables from those for the original geometry exceeded 10%. Thus in the design or selection of meniscal replacements, each of the four parameters should be measured when sizing a replacement tissue. Also tighter tolerances should be placed on the medial meniscal parameters compared to the lateral meniscal parameters.

The fundamentals of cohesive powder consolidation and flow behavior are explained using a reasonable combination of particle and continuum mechanics. By the model stiff particles with soft contacts, universal models are presented which include the elastic-plastic and viscoplastic particle contact behavior with adhesion, load-unload hysteresis and thus energy dissipation, a history-dependent and a nonlinear adhesion force function. With this as the physical basis, incipient powder consolidation, yield and cohesive steady-state flow, consolidation and compression functions, compression and preshear works are explained. As an example, the flow properties of an ultrafine limestone powder are shown. These constitutive models are used to evaluate shear cell test results for apparatus design to ensure reliable powder flow. Finally, conclusions are drawn concerning particle stressing, powder handling behavior and product quality assessment in processing industries.

Calves (n = 106) on four dairy farms were observed for their approachability to humans. All calves experienced similar rearing conditions: Beginning individual pen, after birth until weaning at about 2 months, where they were housed individually and fed milk and a milk replacement; Late individual pen, after weaning until grouping at about 3.5 months, where they were housed individually and fed hay, silage and concentrate feed; Beginning group pen, after grouping until 5 months, where they were housed in groups of 2–5 animals and fed hay, silage and concentrate feed; later group pen, from 5 to 7 months. The number of calves that contacted an experimenter who stood in front of their pens for 10 min was recorded on 6 separate days over 3 months. Latency to touch and time spent in activities during touching such as sucking, licking, biting and rubbing were also measured. There were no significant differences in the latency to touch and the ratio of touch to non-touch calves between the rearing conditions and the farms. The time spent touching was significantly affected by the interaction between the rearing condition and the farm (P

The search for employment was examined as coping through engagement in motivated behavior. A model predicting social networking and employer contact behavior was tested with a sample of persons anticipating college graduation. Proposed relations among behavioral antecedents were primarily drawn from Ajzen's (1985) theory of planned behavior, with the addition of cognitively appraised challenge. Structural equations analysis revealed general support for hypothesized relations among attitude, norms, perceived behavioral control, intentions, and behaviors. Cognitively appraised challenge partially mediated the effects of perceived behavioral control on job search intentions. Significant variance in job search attitude was attributed to a valence by outcome expectancy interaction. Findings may be useful in promoting job search efforts, as well as furthering theoretical delineation of the search process.

Organic electrophotographic receptors have been enabled by the development of unique classes of high dielectric strength glassy polymer coatings which, through insulating are nevertheless capable of transporting injected charge with relatively high mobility and negligible loss to deep traps. Key features of electronic transport in these materials and the underlying physics are described. Additionally, it is demonstrated that these trap free transport polymers provide a unique venue for the exploration of contact behavior and the factors controlling injection efficiency in disordered organic solids.

To model the contact behavior including dynamical effects, a two dimensional mechanical model of elastic rough contact is developed. This model can simulate the contact behaviour between two rough surfaces depending on normal pressure, sliding speed and roughness profiles. The contact between two rough surfaces is reduced to a rough rigid and a rough elastic layer. The elastic layer is modeled by point masses connected by spring-damper elements. The total system is described by coupled ODEs. The number of ODEs and thus the degree of freedom of the model depends on the varying contact conditions. The contact conditions are monitored during the simulation and the simulation interrupts, in case the contact conditions change. The equations of motion are then adapted with respect to the contact constraints. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)

The flow of fine powders is strongly influenced by interparticle contact forces. Depending on the interparticle load force the contact behavior can be elastic, fully plastic or elasto-plastic. We propose a model for the elasto-plastic loading regime that yields a nonlinear dependence of the interparticle adhesion force on the interparticle load force. Interparticle forces are also obtained experimentally. Theoretical results are in reasonable agreement with experimental data.

Contact behavior of presumptive mesodermal cells taken from normal amphibian embryos, hybrid embryos, and hybrid embryos arrested at gastrulation was investigated. Normal cells have a high ability to flatten on a glass substratum and reaggregate. Cells from a viable hybrid which shows some abnormalities in invagination have an intermediate ability to flatten on a glass substratum and an undiminished ability to reaggregate. Cells from three different types of hybrid embryos arrested at gastrulation have a low ability to flatten on a glass substratum and reaggregate. The implications of these results for hypotheses concerning mechanisms of morphogenetic cell movements are discussed.