Subset sum problems with digraph constraints

We introduce and study optimization problems which are related to the well-known Subset Sum problem. In each new problem, a node-weighted digraph is given and one has to select a subset of vertices whose total weight does not exceed a given budget. Some additional constraints called digraph constraints and maximality need to be satisfied. The digraph constraint imposes that a node must belong to the solution if at least one of its predecessors is in the solution. An alternative of this constraint says that a node must belong to the solution if all its predecessors are in the solution. The maximality constraint ensures that no superset of a feasible solution is also feasible. The combination of these constraints provides four problems. We study their complexity and present some approximation results according to the type of input digraph, such as directed acyclic graphs and oriented trees.     

Reclaiming the future: (In)visible dirt borders in Sammy Baloji’s mining photomontages

ABSTRACT

This paper analyses how Baloji’s photographic work Essay on Urban Planning and Mémoire/Kolwezi rely on the dialectic of visibility/invisibility of mining dirt to reveal similarities as well as discrepancies between past and present in capital and labour flows. Conflating archives of humans on display and photographs of abandoned mining sites, Baloji’s figurations of mining dirt unravel how perceptions of dirt were used by the colonial system to impose geographies of exclusion that have become invisible. While they expose how postindependence Congo has failed to appropriate its resources, Baloji’s images of artisanal miners working with mining dirt further epitomise how the disposable objects (often dematerialised via the web) consumed in rich nations involve the disposable lives of workers in the Congo within material dirt borders one can no longer see.     

The Residential Mobility of Seniors Among Different Residential Forms: Analysis of Metropolitan and Rural Issues for Six Contrasted Regions in Québec,Canada

The purpose of this research is to describe and analyze the residential mobility of senior citizens, between 2006 and 2011, among different residential forms in rural and metropolitan areas in the province of Quebec (Canada). A systematic analysis of residential form variability in territories that include both metropolitan and rural areas is performed. First, a typology of residential forms is proposed using a principal component analysis and a hierarchical cluster analysis on environment-related and housing variables. Second, the residential mobility of seniors among these different residential forms is analyzed. The results reveal a certain amount of residential stability among seniors, except where specific conditions are met, such as the death of a spouse or the onset of health problems limiting day-to-day activities. For those who moved, high-rise habitat areas and mixed areas with older rental apartments held the greatest attraction. However, suburban areas attracted the largest number of seniors because these areas account for a sizeable portion of the real estate market.     

From Foster Care to Adoption and Guardianship: A Twenty-First Century Challenge

For nearly four decades, child welfare policy and practice have focused on the achievement of legal permanence for children in foster care. Although federal child welfare policy has resulted in the movement of children from state custody to legally permanent adoptive or guardianship families, little is known about the quality and enduring nature of these placements. A significant challenge of the twenty-first century child welfare system is how to ensure the well-being of children currently living with adoptive parents or guardians. This paper discusses child welfare policy and trends related to post-permanency well-being, including the decrease in Title IV-E foster care caseloads nationwide and the simultaneous increase in Title IV-E adoptive and guardianship caseloads. We highlight the needs of a twenty-first century child welfare system, including increased federal efforts to ensure child permanence and well-being after legal adoption or guardianship has been achieved, as well as more rigorous longitudinal and interdisciplinary research focused on the post-permanency adjustment of children and their families.     

Participatory Art as a Social Practice of Commoning to Reinvent the Right to the City

The right to the city is a concept that helps rethink spatial–social dynamics, which has recently reinvigorated the field of organization studies. Following Lefebvre and considering the failure of both the market and the state, other scholars pinpoint the need to rethink social–spatial and geographical–historical relations. They do so by theorizing the city as a host for urban commons. Collective and non-commodified, these spatial–social experiences need to be constantly reproduced and preserved through commoning practices in the struggle against spatial injustice. A case study shows that a civil society organization (CSO) uses participatory art to (re)produce urban commons at the level of a local community and to redress partially spatial injustice. We theorize participatory art-making as a social practice of commoning, i.e., a process of organizing for the commons—collective art-based activities to serve a community—and of the common—to (re)produce a community while performing them. Such commoning practices are not only about sharing urban resources but also about using and experiencing differently urban spaces. By making participatory artworks in public spaces and co-designing street furniture with residents of poor areas, TDA helps to better cope with the tensions between residents and local authorities and between amateurs and professional artists. By negotiating the long-term implementation of these creative artworks in the public space with public authorities, TDA has fostered the empowerment of inhabitants as they have experienced citizens’ reappropriation of some public spaces in Marseille.     

‘Are we to become a gender university?’ Facets of resistance to a gender equality project

Gender equality (GE) is something ‘we cannot not want’. Indeed, the pursuit of equal rights, responsibilities and opportunities for all women and men throughout a society freed from gendered oppression is widely visible in recent organizational GE initiatives. In practice, however, GE initiatives often fail in challenging gendered norms and at effecting deep‐seated change. In fact, GE measures tend to encounter resistance, with a gap between saying and doing. Using a GE project at a Swedish university, we examined the changing nature of reactions to GE objectives seeking to understand why gender inequality persists in academia. We used ‘resistance’ to identify multiple, complex reactions to the project, focusing on the discursive practices of GE. Focusing our contextual analysis on change and changes in reactions enabled a process‐oriented analysis that revealed gaps where change is possible. Thus, we argue that studying change makes it possible to identify points in time where gendered discriminatory norms are more likely to occur. However, analysing discursive practices does not itself lead to change nor to action. Rather, demands for change must start with answering, in a collaborative way, what problem we are trying to solve when we start a new GE project, in order to be relevant to the specific context. Otherwise, GE risks being the captive of consensus politics and gender inequality will persist.     

Activism among older women in Quebec, Canada: changing the world after age 65

The aim of this article is to examine senior women's involvement experience in Quebec, Canada. Study results are based on a qualitative methodology, and shed light on family history and continuity in the involvement trajectory, diversity in terms of group type and involvement practices, and gender differences in involvement. The meaning that older women attribute to their involvement is also addressed, including attitudes toward feminism. The discussion highlights the extent to which older women's involvement has been marked by their life trajectories, above and beyond their age. In sum, their involvement in the private and public spheres is quite impressive.     

Evaluating school and parent reports of the national student achievement testing system (SIMCE) in Chile: Access,comprehension, and use

This evaluation examined school and parent reports of the national student achievement testing system (SIMCE) in Chile regarding three dimensions: access, comprehension, and use. We conducted phone surveys with a representative sample of directors (N = 375), teachers (N = 1145) and parents (N = 625), and we collected more in-depth data through interviews and focus groups in 16 of these schools. The results indicate that access to the reports is not an obstacle to use for school actors, but it is for parents. While summative ratings of the reports in terms of their clarity and utility were generally very positive, the actual recall and interpretation of even basic information (assessed through case scenarios) was incorrect for a majority of teachers and parents, and reported uses of the information were both intended and unintended in nature. We also found some statistically significant differences regarding comprehension and use among subgroups of our sample. Our findings are especially relevant given the expectations attached to the use of the reports for school improvement on the one hand, and parents’ behavior as critical consumers of education on the other hand.     

Children’s Strategies for Agency in Preschool

This article is based on an ethnographic study of children’s everyday life in Swedish preschools. The ethnography is used to explore children’s strategies for influencing, defending and constructing the social order of a preschool institution. The focus of our concern is on how the children, in their interactions with each other and with the preschool teachers, manage the collective regulation and how they negotiate their participation in collective activities. There is an inherent tension between free play and the high degree of routinised and collective activities within the preschool institution. The study shows that children are active in playing at the border, acting as if the institution is the children’s place. It also shows how they draw on different strategies as resources for managing the regulations, accounting for personal autonomy and negotiating the social order. In taking a child perspective and acknowledging children as active agents, it is possible to see how they influence and shape their everyday life in a preschool context. In addition, the article illustrates individual children’s strategic and pragmatic use of resources and in doing so contribute to their own childhood and thereby become part of a social and cultural construction process.     

Number of children and later-life mortality among Finns born 1938–50

We investigated the association between number of offspring and later-life mortality of Finnish men and women born 1938–50, and whether the association was explained by living conditions in own childhood and adulthood, chronic conditions, fertility timing, and unobserved characteristics common to siblings. We used a longitudinal 1950 census sample to estimate mortality at ages 50–72. Relative to parents of two children, all-cause mortality is highest among childless men and women, and elevated among those with one child, independently of observed confounders. Fixed-effect models, which control for unobserved characteristics shared by siblings, clearly support these findings among men. Cardiovascular mortality is higher among men with no, one, or at least four children than among those with two. Living conditions in adulthood contribute to the association between the number of children and mortality to a greater extent than childhood background, and chronic conditions contribute to the excess mortality of the childless.