On the fractionality of the path packing problem

Given an undirected graph G=(N,E), a subset T of its nodes and an undirected graph (T,S), G and (T,S) together are often called a network. A?collection of paths in G whose end-pairs lie in S is called an integer multiflow. When these paths are allowed to have fractional weight, under the constraint that the total weight of the paths traversing a single edge does not exceed 1, we have a fractional multiflow in G. The problems of finding the maximum weight of paths with end-pairs in S over all fractional multiflows in G is called the fractional path packing problem. In 1989, A. Karzanov had defined the fractionality of the fractional path packing problem for a class of networks {G,(T,S)} as the smallest natural D such that for any network from the class, the fractional path packing problem has a solution which becomes integer-valued when multiplied by D (see A.?Karzanov in Linear Algebra Appl. 114–115:293–328, 1989). He proved that the fractional path packing problem has infinite fractionality outside a very specific class of networks, and conjectured that within this class, the fractionality does not exceed 4. A.?Karzanov also proved that the fractionality of the path packing problem is at most 8 by studying the fractionality of the dual problem. Special cases of Karzanov’s conjecture were proved in or are implied by the works of L.R.?Ford and D.R.?Fulkerson, Y.?Dinitz, T.C.?Hu, B.V.?Cherkassky, L.?Lov?sz and H.?Hirai. We prove Karzanov’s conjecture by showing that the fractionality of the path packing problem is at most 4. Our proof is stand-alone and does not rely on Karzanov’s results.     

Feeling Social Movements: Theoretical Contributions to Social Movement Research on Emotions

Recent literature provides evidence that emotions are intrinsic to the constitution of social movements. The present review examines how scholars theorize emotions in their empirical studies and focuses on the following topics: emotion work, emotional framing, emotional cultures and emotional opportunity structures. The combination of several constructs in the analysis of emotions signals a shift toward integration of preexisting perspectives common in the field of social movements.     

Interorganizational Partnerships as a Strategy for Lobbying: Nonprofit Administrators’ Perspectives on Collaborating for Systems-Level Change

Participation in coalitions has been identified as a policy advocacy behavior for nonprofit organizations, although few studies have examined nonprofit leaders’ perceptions of coalition building as a strategy for lobbying. This study conducted focus groups and in-person interviews with nonprofit administrators to explore how interorganizational collaboration is utilized to address their organizations’ policy advocacy goals. The findings indicate that nonprofit administrators view their participation in coalitions as a means of achieving several policy advocacy goals, including increasing their capacity to lobby and protecting them from exposure as lobbyists. Implications for practice and research are provided.     

Translation sociology and social capital in rural development initiatives. A case study from the Italian Alps

This article analyses the results of a European ‘research and demonstration’ project promoting multifunctional and sustainable agriculture in Alpine regions through a participatory approach. It focuses in particular on initiatives undertaken by a local farmers group in the Italian Alpine area of Val di Sole, the purpose being to draw attention to the role of social dynamics in fostering sustainable rural development in a participatory context. In order to accomplish this objective, two key sociological approaches to the study of rural development, namely social capital and the sociology of translation, are considered. The former focuses on the relational capital available to a group of actors and which can be mobilised in a development initiative. The latter views change in social practices as resulting from a cycle of phases where the problem, its solution, and the identity of the actors are constantly transformed and negotiated. By contrasting the two theoretical approaches in relation to the outcomes of two specific actions implemented in the valley we suggest that the sociology of translation offers a more effective tool with which to capture the complexity of social dynamics involved in a rural development initiative.     

Risk taking on behalf of others: The role of social distance

Individuals take decisions on behalf of others in many different contexts. In this paper, we focus on lotteries with negative expected value and study if (and how) risky choices made on behalf of another person differ i) compared to decisions which do not affect anyone else, and ii) depending on the social distance between who makes the decision and who is affected by it. Our results show that social distance (i.e., whether the person affected by one’s decision is an unknown stranger or a friend) is an important determinant when people decide on behalf of others. Moreover, when deciding on behalf of a friend rather than only for themselves or a stranger, average individual behavior is closer to expected value maximization, exhibiting less risk taking. These findings suggest that responsibility for others’ outcome and the empathy gap affect the decision making process, particularly when the social distance is shortened. The results are robust to different feedback frequencies. Controlling for order effects shows that experiencing a decrease in social distance is crucial in activating this mechanism.     

Understanding the “Russian Mortality Paradox” in Central Asia: Evidence from Kyrgyzstan

In the former Soviet republics of central Asia, ethnic Russians have exhibited higher adult mortality than native ethnic groups (e.g., Kazakh, Kyrgyz, Uzbek) in spite of the higher socioeconomic status of ethnic Russians. The mortality disadvantage of ethnic Russians at adult ages appears to have even increased since the breakup of the Soviet Union. The most common explanation for this “Russian mortality paradox,” is that deaths are better reported among ethnic Russians. In this study, we use detailed mortality data from Kyrgyzstan between 1959 and 1999 to evaluate various explanations for the Russian mortality paradox: data artifacts, migration effects, and cultural effects. We find that the most plausible explanation is the cultural hypothesis because the personal behaviors that appear to generate a large part of the observed mortality differences (alcohol consumption, in particular) seem to be closely tied to cultural practices. We examine the implications of this finding for understanding the health crisis in post-Soviet states.     

The impact of response options ordering on respondents’ answers to rating questions: results of two experiments

This paper aims to explore the response-order effects for rating questions presented in item-by-item and grid formats. It was hypothesized that the primacy effect occurs for both formats of questions, and that this effect is dependent on age, education, and type of device used for responding to questions. Two randomized experiments were conducted in 28 pre-course surveys of massive open online course students (N = 22,910). Our findings suggest that the order of response options affects respondents’ perception of the option lists and their responding patterns. The primacy effect is found for the item-by-item question, while there is no evidence for the presence of such an effect for the grid question format. Primacy effect for the item-by-item layout is lower for respondents with higher education degree while there are no interaction effects between ordering and age, gender, and type of device. For a grid question, mixed results were observed.