Four bugs on a rectangle

The problem of four bugs in cyclic pursuit starting from a 2-by-1 rectangle is considered, and asymptotic formulas are derived to describe the motion. In contrast to the famous case of four bugs on a square, here the trajectories quickly freeze to essentially one dimension. After the first rotation about the centre point, the scale of the configuration has shrunk by a factor of 10^427907250, and this number is then exponentiated four more times with each successive cycle. Relations to Knuth’s double-arrow notation and level-index arithmetic are discussed

A computational approach to the study of the stability of pier riprap at the Middle Fork Feather River

This paper discusses the use of various technologies and advanced computational modeling techniques that were combined for monitoring the performance of pier riprap on the basis of a field case study – Pier 3 of a bridge over the Middle Fork Feather River – in northern California, USA. The first phase involved capturing the field condition of the bridge site using sonar instrumentation technology in order to obtain high resolution bathymetry data. The second phase entailed enhancement and transformation of the scanned bathymetric data into a 3D CAD model to be used as the initial geometry for numerical modeling. A Fluid Structure Interaction (FSI) numerical approach was applied to simulate the rock incipient motion i.e. shear failure by coupling Computational Fluid Dynamics (CFD) software STAR-CCM+ and a Computational Structural Mechanics (CSM) software LS-DYNA. Several coupled simulations have been performed with varying flow conditions to identify shear failure conditions for the riprap apron

Fatigue strength of common tibial intramedullary nail distal locking screws

Premature failure of either the nail and/or locking screws with unstable fracture patterns may lead to angulation, shortening, malunion, and IM nail migration. Up to thirty percent of all unreamed nail locking screws can break after initial weight bearing is allowed at 8–10 weeks if union has not occurred. The primary problem this presents is hardware removal during revision surgery. The purposes of our study was to evaluate the relative fatigue resistance of distal locking screws and bolts from representative manufacturers of tibial IM nail systems, and develop a relative risk assessment of screws and materials used. Evaluations included quantitative and qualitative measures of the relative performance of these screws

Building an Aerial-Ground Robotics System for Precision Farming: An Adaptable Solution

[No abstract available

Male and female physical intimate partner violence and socioeconomic position: a cross-sectional international multicentre study in Europe

Objectives: This work explores the association between socioeconomic position (SEP) and intimate partner violence (IPV) considering the perspectives of men and women as victims, perpetrators and as both (bidirectional). Study Design: Cross-sectional international multicentre study. Methods: A sample of 3496 men and women, (aged 18-64 years), randomly selected from the general population of residents from six European cities was assessed: Athens, Budapest, London, Östersund, Porto and Stuttgart. Their education (primary, secondary and university), occupation (upper white-collar, lower white-collar and blue collar) and unemployment duration (never, ≤12 months and >12 months) were considered as SEP indicators and physical IPV was measured with the Revised Conflict Tactics Scales. Results: Past year physical IPV was declared by 17.7% of women (3.5% victims, 4.2% perpetrators and 10.0% bidirectional) and 19.8% of men (4.1% victims, 3.8% perpetrators and 11.9% bidirectional). Low educational level (primary vs. university) was associated with female victimization (adjusted Odds Ratio, 95% confidence interval: 3.2, 1.3-8.0) and with female bidirectional IPV (4.1, 2.4-7.1). Blue collar occupation (vs. upper white) was associated with female victimization (2.1, 1.1-4.0), female perpetration (3.0, 1.3-6.8) and female bidirectional IPV (4.0, 2.3-7.0). Unemployment duration was associated with male perpetration (> 12 months of unemployment vs. never unemployed: 3.8, 1.7-8.7) and with bidirectional IPV in both sex (women: 1.8, 1.2-2.7; men: 1.7, 1.0-2.8). Conclusions: In these European centers, physical IPV was associated with a disadvantaged socioeconomic position. A consistent socioeconomic gradient was observed in female bidirectional involvement, but victims or perpetrators-only presented gender specificities according to levels of education, occupation differentiation and unemployment duration potentially useful for designing interventions

Perspectives of Portuguese People with Physical Disabilities Regarding Their Sexual Health: A Focus Group Study

The World Health Organization has considered sexual health as a major dimension of global health and a sexual right. However, the sexual health of people with physical disabilities is still poorly addressed by health and social care professionals, and it is very stigmatized by society. This study aimed to assess the perspectives of Portuguese people living with physical disabilities regarding issues affecting their sexual health. Nine women and 17 men with different physical disabilities participated in the study. Participants were recruited from a professional rehabilitation facility located in the North of Portugal and were assigned to four groups in one-hour sessions. Three main categories emerged from the content analysis: (1) meanings and beliefs regarding sexuality; (2) experiences of sexuality; (3) necessary changes. Despite the positive social changes towards sexuality, participants expressed that their sexual rights are still unfulfilled, as they live in a context that perpetuates their dependency. They pointed out low self-esteem, prejudice and social isolation, poor architectural accessibility and scarcity of financial support as some of the barriers to their lives and their sexual health. Finally, participants identified the main needs regarding their sexual health, such as: access to specialized information; training for health professionals. This study gives voice to people with physical disabilities and sheds light into both individual and contextual factors affecting their sexual health. Of utmost importance, this study draws attention to the need for reinforcing sexuality of people with disabilities in the social agenda and brings implications for future research and practice.This study was supported by a Grant attributed to the first author by the Portuguese Foundation for Science and Technology (SFRH/BD/112168/2015)info:eu-repo/semantics/publishedVersio

Mesozoic Alpine facies deposition as a result of past latitudinal plate motion

The fragmentation of Pangaea as a consequence of the opening of the Atlantic Ocean is documented in the Alpine-Mediterranean region by the onset of widespread pelagic sedimentation1. Shallow-water sediments were replaced by mainly pelagic limestones in the Early Jurassic period, radiolarian cherts in the Middle-Late Jurassic period, and again pelagic limestones in the Late Jurassic-Cretaceous period. During initial extension, basin subsidence below the carbonate compensation depth (CCD) is thought to have triggered the transition from Early Jurassic limestones to Middle-Late Jurassic radiolarites. It has been proposed that the transition from radiolarites to limestones in the Late Jurassic period was due to an increase in calcareous nannoplankton abundance when the CCD was depressed below the ocean floor. But in modern oceans, sediments below the CCD are not necessarily radiolaritic. Here we present palaeomagnetic samples from the Jurassic-Cretaceous pelagic succession exposed in the Lombardian basin, Italy. On the basis of an analysis of our palaeolatitudinal data in a broader palaeogeographic context, we propose an alternative explanation for the above facies tripartition. We suggest that the Lombardian basin drifted initially towards, and subsequently away from, a near-equatorial upwelling zone of high biosiliceous productivity. Our tectonic model for the genesis of radiolarites adds an essential horizontal plate motion component to explanations involving only vertical variations of CCD relative to the ocean floor. It may explain the deposition of radiolarites throughout the Mediterranean and Middle Eastern region during the Jurassic period