Numerical simulation of soil-structure interaction experiments on shallow founded structures for different mass configurations

Soil-Structure Interaction (SSI) phenomena and foundation rocking can modify the structural response signifi- cantly with respect to the response predicted adopting the fixed-base assumption. The importance of SSI and rocking depends, among other factors, on the structural mass and the distribution of static stresses at the soil-foundation interface. Within this context, an experimental campaign was carried out aiming to investigate the SSI effects on the response of a 3m x 3m x 5m steel- framed structure. The prototype structure, called EUROPROTEAS, was founded on a shallow footing at the well-characterised Euroseistest site, while its mass was either 18Mgr or 9Mgr. The present study simulates free vibration experiments, placing particular emphasis on soil nonlinearity and soil-foundation interface. A novel approach to simulate gaps at the soil-foundation interface, foundation rocking and to manipulate interface stresses under static conditions is presented. The three aspects are shown to significantly affect the response, while they are found to be more important for the lighter structure

The Predation Game: Does dividing attention affect patterns of human foraging?

AbstractAttention is known to play an important role in shaping the behaviour of both human and animal foragers. Here, in three experiments, we built on previous interactive tasks to create an online foraging game for studying divided attention in human participants exposed to the (simulated) risk of predation. Participants used a “sheep” icon to collect items from different target categories randomly distributed across the display. Each trial also contained “wolf” objects, whose movement was inspired by classic studies of multiple object tracking. When participants needed to physically avoid the wolves, foraging patterns changed, with an increased tendency to switch between target categories and a decreased ability to prioritise high reward targets, relative to participants who could safely ignore them. However, when the wolves became dangerous by periodically changing form (briefly having big eyes) instead of by approaching the sheep, foraging patterns were unaffected. Spatial disruption caused by the need to rapidly shift position—rather the cost of reallocating attention—therefore appears to influence foraging in this context. These results thus confirm that participants can efficiently alternate between target selection and tracking moving objects, replicating earlier single-target search findings. Future studies may need to increase the perceived risk or potential costs associated with simulated danger, in order to elicit the extended run behaviour predicted by animal models of foraging, but absent in the current data

An Approach of Integrating Communication Services in Applications for Android-Based Digital TV Receivers

Digital TV receivers are becoming increasingly powerful devices allowing consumers to not only watch television broadcasts but also to access the Internet or communicate to other devices in the same local area network through either an Ethernet connection or by using a wireless connection. As the living room represents a meeting place for family and friends to gather and socialize in, the possibility of playing informal games using the television set as the interaction device is very attractive. This paper presents a developed application that integrates new communication capabilities of digital TV receivers running the Android OS. The application is a game showing its content overlaid on top of a television program whereas Android mobile devices are used as controllers. The performance of the application is tested by measuring the response times of the various communication services and by analyzing feedback from a selected group of users

Delayed Care and Mortality Among Women and Men with Myocardial Infarction

Background-Women with ST-segment-elevation myocardial infarction (STEMI) have higher mortality rates than men. We investigated whether sex-related differences in timely access to care among STEMI patients may be a factor associated with excess risk of early mortality in women. Methods and Results-We identified 6022 STEMI patients who had information on time of symptom onset to time of hospital presentation at 41 hospitals participating in the ISACS-TC (International Survey of Acute Coronary Syndromes in Transitional Countries) registry (NCT01218776) from October 2010 through April 2016. Patients were stratified into time-delay cohorts. We estimated the 30-day risk of all-cause mortality in each cohort. Despite similar delays in seeking care, the overall time from symptom onset to hospital presentation was longer for women than men (median: 270 minutes [range: 130-776] versus 240 minutes [range: 120-600]). After adjustment for baseline variables, female sex was independently associated with greater risk of 30-day mortality (odds ratio: 1.58; 95% confidence interval, 1.27-1.97). Sex differences in mortality following STEMI were no longer observed for patients having delays from symptom onset to hospital presentation of (odds ratio: 0.77; 95% confidence interval, 0.29-2.02). Conclusions-Sex difference in mortality following STEMI persists and appears to be driven by prehospital delays in hospital presentation. Women appear to be more vulnerable to prolonged untreated ischemia

Interaction Ruling Animal Collective Behaviour Depends on Topological rather than Metric Distance: Evidence from a Field Study

Numerical models indicate that collective animal behaviour may emerge from simple local rules of interaction among the individuals. However, very little is known about the nature of such interaction, so that models and theories mostly rely on aprioristic assumptions. By reconstructing the three-dimensional position of individual birds in airborne flocks of few thousands members, we prove that the interaction does not depend on the metric distance, as most current models and theories assume, but rather on the topological distance. In fact, we discover that each bird interacts on average with a fixed number of neighbours (six-seven), rather than with all neighbours within a fixed metric distance. We argue that a topological interaction is indispensable to maintain flock's cohesion against the large density changes caused by external perturbations, typically predation. We support this hypothesis by numerical simulations, showing that a topological interaction grants significantly higher cohesion of the aggregation compared to a standard metric one.Comment: To be submitted to PNAS - 25 page