Generating a smallest binary tree by proper selection of the longest edges to bisect in a unit simplex refinement

In several areas like global optimization using branch-and-bound methods for mixture design, the unit n-simplex is refined by longest edge bisection (LEB). This process provides a binary search tree. For \(n>2\), simplices appearing during the refinement process can have more than one longest edge (LE). The size of the resulting binary tree depends on the specific sequence of bisected longest edges. The questions are how to calculate the size of one of the smallest binary trees generated by LEB and how to find the corresponding sequence of LEs to bisect, which can be represented by a set of LE indices. Algorithms answering these questions are presented here. We focus on sets of LE indices that are repeated at a level of the binary tree. A set of LEs was presented in Aparicio et al. (Informatica 26(1):17–32, 2015), for \(n=3\). An additional question is whether this set is the best one under the so-called \(m_k\)-valid condition.     

Determinants of microbat communities in urban forest remnants: a rapid landscape scale assessment

Urban Ecosystems - Urbanisation affects fauna in many ways; with some species persisting and going on to dominate urban habitats, while other species decline over time due to habitat disturbance...     

Stereoscopic visions: reading colonial and contemporary African photography

This piece argues for the importance of critical engagements with photographs in order to explore and rethink the past, to reflect on the present and to imagine the future. It provides a brief overview of the articles that constitute the first part of the Social Dynamics special issue on photography in Africa, a collection that contributes to the growing body of scholarship that deepens our understandings of the significance of photography on the continent.     

Sexual practices and the duration of last heterosexual encounter: findings from the Australian longitudinal study of health and relationships

This study investigated the association between sexual practices and duration of a sexual encounter. Using data from a population-based computer-assisted telephone survey of 8,656 Australians aged 16 to 64 years, four distinct patterns of sexual practices among respondents were found: "basic sexual encounter" (involving mainly kissing, cuddling, stroking one's partner and being stroked, and vaginal intercourse), "basic sexual encounter plus oral sex," "all assessed sexual practices" (all sexual behaviors included in the survey), and "mainly vaginal intercourse" (characterized by lower levels of kissing, cuddling, and stroking). For both men and women, respondents classified in the basic sexual encounter plus oral sex, and all assessed sexual practices clusters reported significantly longer durations than those in the basic sexual encounter group, whereas respondents in the mainly vaginal intercourse cluster reported shorter durations. These differences were found even after allowing for demographic differences in sexual duration-specifically, age and partner type of the most recent opposite-sex partner. These findings add to the understanding of what typically happens in a sexual encounter. Overall, longer sexual encounters appear to be associated with the inclusion of the least common sexual practices-namely, oral sex and self-stimulation.     

Improving wheelchair prescription: an analysis of user needs and existing tools

Wheelchair users experience many situations that affect the stability and associated performance of their wheelchair. Stability is affected by user characteristics and abilities, environmental features and conditions, and wheelchair modification and accessories. Wheelchair prescribers need effective tools and methods to provide quantitative evaluation and prediction of the behavior of the user-wheelchair system in a variety of static and dynamic situations. Such information is very important to guide efficient management of associated risks and adjust chairs accordingly. This project involves a user-centered approach for design and evaluation of a load cell based wheelchair stability assessment system (Wheel-SAS). Here, the current methods for assessing stability are described, and their shortcomings explained. The user-centered design approach being applied to the development of the associated Wheel-SAS hardware and software is described. Future work including semi-structured interviews and an online survey with wheelchair prescribers and associated healthcare professionals for deriving user requirements and a design specification for a load cell system for measuring dynamic wheelchair stability are detailed.     

Changing Trends of Mothers’ Active and Passive Childcare Times

This paper explores how mothers’ allocation of types of time with children and the determinants of this allocation have changed during 1981–1997 in the United States, using Time Use Longitudinal Panel Study and Family Interaction, Social Capital and Trends in Time Use. Data reveal that active time with children has increased for the case of educated working mothers with young children. Estimations also provide evidence that although different uses of time are substitutes; active time is less sensitive than passive. Moreover, the relationship between active and passive time with children has changed over time.     

Climate change and population migration in Brazil’s Northeast: scenarios for 2025–2050

This research contributes to an understanding of the relationship between climate change, economic impacts and migration. We model the long-term relationship (up to 45 years of projection) between demographic dynamics—particularly migration—driven by changes in the performance of the economy due to climate changes in the Northeast region of Brazil. The region is of particular relevance to the study of climate change impacts given its large human population (28% of Brazil’s population) and high levels of impoverishment, having an extensive semi-dry area which will be severely impacted by growing temperatures. Ultimately, the integrated model generates state- and municipal-level migration scenarios based on climate change impacts on the primary economic sectors and their articulations with other sectors. Results suggest that the predicted climate changes will impact severely the agriculture sector in the region, acting as a potential migration push factor to other regions in the country. Finally, we discuss how the increased vulnerability of some groups, particularly migrants, can be factored into Brazilian public policy and planning.