On the algorithmic aspects of strong subcoloring

A partition of the vertex set V(G) of a graph G into \(V(G)=V_1\cup V_2\cup \cdots \cup V_k\) is called a k-strong subcoloring if \(d(x,y)\ne 2\) in G for every \(x,y\in V_i\), \(1\le i \le k\) where d(x, y) denotes the length of a shortest x-y path in G. The strong subchromatic number is defined as \(\chi _{sc}(G)=\text {min}\{ k:G \text { admits a }k\)-\(\text {strong subcoloring}\}\). In this paper, we explore the complexity status of the StrongSubcoloring problem: for a given graph G and a positive integer k, StrongSubcoloring is to decide whether G admits a k-strong subcoloring. We prove that StrongSubcoloring is NP-complete for subcubic bipartite graphs and the problem is polynomial time solvable for trees. In addition, we prove the following dichotomy results: (i) for the class of \(K_{1,r}\)-free split graphs, StrongSubcoloring is in P when \(r\le 3\) and NP-complete when \(r>3\) and (ii) for the class of H-free graphs, StrongSubcoloring is polynomial time solvable only if H is an induced subgraph of \(P_4\); otherwise the problem is NP-complete. Next, we consider a lower bound on the strong subchromatic number. A strong set is a set S of vertices of a graph G such that for every \(x,y\in S\), \(d(x,y)= 2\) in G and the cardinality of a maximum strong set in G is denoted by \(\alpha _{s}(G)\). Clearly, \(\alpha _{s}(G)\le \chi _{sc}(G)\). We consider the complexity status of the StrongSet problem: given a graph G and a positive integer k, StrongSet asks whether G contains a strong set of cardinality k. We prove that StrongSet is NP-complete for (i) bipartite graphs and (ii) \(K_{1,4}\)-free split graphs, and it is polynomial time solvable for (i) trees and (ii) \(P_4\)-free graphs.     

Knowledge ties among subsidiaries in MNCs: A multi-level conceptual model

While ties among subsidiaries—the key players of a MNC network—are a prerequisite for the formation of the network and the flow of knowledge within the organization, we know little about factors influencing the formation of such ties. By building on the literature on inter-firm networks and knowledge-based view of the firm, we develop a multi-level model consisting of subsidiary characteristics, dyadic dynamics, and salient contextual factors to explain the inter-subsidiary collaboration for knowledge development and exchange. We bring to the fore the importance of examining multiple dimensions in understanding what predicts tie formation and the efficacy of these ties in creating a knowledge advantage. This paper advances the notion of subsidiary knowledge networking capability—the ability to form, manage, and leverage a network for gaining and sharing knowledge—and suggests that such capability is critical for subsidiaries and by extension the MNC, to achieve a competitive advantage.     

Multiple Migration and Use of Ties: Bangladeshis in Italy and Beyond

This article analyses previous multiple migratory trajectories of Bangladeshi first generation migrants before their arrival in Italy and within Italy. It also uncovers the role of social networks and transnational ties in their multiple migrations. The findings show that their first international migration was mainly shaped by their family’s socio-economic condition and transnational kinship networks. They already had someone from their family or close relatives in the preferred country with whom they were connected. Their onward relocations until arriving in Italy, in most cases, was to achieve the socio-economic success and legal status that they had failed to attain in their first and subsequent destinations, but the transnational connections with friends or acquaintances are a key resource facilitating these remigrations. Bangladeshis who arrived in Italy from various countries mostly had networks, either with someone from their local district in Bangladesh or with their earlier fellow migrants who moved to Italy before them.     

On the meaning and implications of facial prominence

Archer et al. (1983) found that visual depictions (e.g., photographs) of men tend to show more face and less of the body (a characteristic that was termed high face-ism) than visual depictions of women. Furthermore, photographs (of both men and women) high in face-ism elicited more favorable impressions than photographs low in face-ism. The present studies examined possible reasons for sex differences in face-ism and their implications concerning the effects of high and low face-ism on interpersonal perception. Study 1 showed that the greater face-ism in photographs of men was less pronounced when the photographs were taken from periodicals that are oriented toward women's issues. Study 2 showed that photographs high in face-ism received higher ratings on dominance, a dimension related to masculinity, but not on positivity, a dimension related to femininity. This study also indicated that facial expressions provided more information about degrees of positivity while body cues provided more information about dominance and submission. Consistent with these latter results, Study 3 showed that amateur drawings portraying kind or hostile persons showed more of the face while drawings presenting dominant or weak persons showed more of the body. The two phenomena—the relationship of high face-ism with impressions of high dominance and the different types of information transmitted by the face and body—were considered in the discussion.The author would like to express his appreciation to Diana R. Satin and BiancaMaria (Mia) Penati for their assistance with this project.     

The Endowment Effect on Academic Chores Trade-Off (ACTO)

The present study aimed to investigate three questions concerning Kahneman’s Endowment Effect. (a) Does the Endowment Effect apply to negotiations on intangible items such as intellectual resources and time invested in academic chores? (b) Does the sequence in which proposals are presented to the negotiators influence the Endowment Effect and, if so, how? (c) Does the Endowment Effect have the same impact in on-going negotiations as in one-shot negotiations? The investigation focused on the trade-off made by students between advanced courses and seminars, which we term as Academic Chores Trade-Off (ACTO). The results indicated the existence of the Endowment Effect in negotiations on the above intangible items (ACTO) but could also be partially interpreted as reflecting the negotiators attempts to improve their positions. The results also supported the existence of a Sequence Effect combined with an intensification of the Endowment Effect. The Endowment Effect in on-going negotiations was not found to be significantly different from that in the one-shot format.     

The effect of nonverbal sensitivity on social interaction

This study examined the relation between decoding ability and quality of dyadic interaction of college roommate pairs. It was found that pairs with members who were both high in decoding (HH pairs) rated their interactions somewhat more positively than pairs in which one or both roommates were low (HL and LL pairs). This effect was more pronounced for ratings reflecting emotional sharing (e.g., gave and received support) than for ratings reflecting influence (e.g., initiated the interaction). For emotional sharing only, the difference between the HH pairs and the HL plus LL pairs was significant. The relative advantage of the HH pairs in emotional sharing and relative disadvantage in influence was more pronounced for males and less for females, suggesting a reversal of traditional sex-role behavior. When differences in decoding ability within roommate pairs were considered, the results showed that, in dyads with at least one good decoder (HH and HL pairs), the interaction was rated more positively by the roommate who was lower in decoding ability. The concept and measure of decoding ability and their implications for interaction and sex-role behavior were discussed.This research was supported in part by NIMH Grant # R01 MH 40498 to Miron Zuckerman.     

Nonverbal strategies for decoding deception

This study tested the hypothesis that judges who suspect deception would be less influenced by controllable channels (facial expresions) relative to leaky channels (voice and body) than judges who do not suspect deception. The Nonverbal Discrepancy Test, comprised of video (face or body) cues paired with audio cues, was administered to subjects with the information that the person shown in the test never lied, sometimes lied, or very often lied; in a fourth condition (control) there was no mention of deception. In some cases, the video and audio components of the discrepancy test depicted the same affect while in other cases they depicted different affects. Subjects who expected more deception were relatively less influenced by the facial component of the affectively discrepant video-audio pairings. These subjects were also less accurate at decoding affectively consistent videoaudio pairings, especially those involving facial cues. Finally, subjects who expected more deception became less accurate decoders of consistent video-audio pairings during the second half of the test but learned to recognize video-audio discrepancies better. The results suggest that suspicion of deception led subjects to discount facial cues. Results for the control group indicated that even in the absence of explicit information, discrepant messages create a suspicion of deception.Preparation of this paper was supported in part by the National Science Foundation.     

Collaboration outcomes in a public sector: impact of governance,leadership, interdependence and relational capital

Collaboration between public agencies is critical to address social issues effectively. The main objective of this research was to identify the factors that lead to successful achievement of desired collaboration outcomes that could eventually lead to societal outcomes. The factors identified were: transformational leadership, governance, interdependence, and relational capital. An integrated framework was developed based on collaboration governance framework (CGF) of Ansell and Gash (J Public Adm Res Theory 18:543–571, 2008). The CGF framework has integrated the following four broad variables that are responsible for achieving the desired collaboration outcomes: starting conditions, institutional design, leadership, and collaborative process. The study was conducted in Malaysia by sending questionnaires to 500 officers in various ministries who were involved in planning, formulating, and implementing public policies. The main findings of this study are: (1) transformational leadership influences governance, interdependence, relational capital, and collaboration outcomes; (2) governance has impact on relational capital, interdependence, and collaboration outcomes; (3) relational capital and interdependence result in positive collaboration outcomes; (4) dimensions of governance are inter-related; and (5) interdependence and relational capital are strongly correlated. This research adds significantly to the literature on collaborative governance. The implications and limitations of the study are discussed.     

Education for all – but not Hong Kong’s ethnic minority students

School participation rates in Hong Kong are acknowledged to be high but not always for the city’s ethnic minority students. Case study was used to portray the ‘out of school’ phenomenon for ethnic minority students at a secondary school in Hong Kong through the experiences of one such ethnic minority student. Morshed, a Pakistani student, participated with the researchers in an unstructured in-depth interview. In addition, interviews were also conducted with the principal, two teachers, and one support staff from the school. The study showed the complex interaction of school contexts and personal life issues that influenced Morshed’s dropping out of school. Implications are drawn for providing better school support that can facilitate more positive schooling experiences for Hong Kong’s ethnic minority students.     

Multiseason transmission for Rift Valley fever in North America

ABSTRACT

Rift Valley fever is a vector-borne disease, primarly found in West Africa, that is transmitted to humans and domestic livestock. Its similarities to the West Nile virus suggest that establishment in the developed world may be possible. Rift Valley fever has the potential to invade North America, where seasons play a role in disease persistence. The values for the basic reproductive number show that, in order to eradicate the disease, the survival time of mosquitoes must decrease below 8.67 days. Mechanisms such as aggressive spraying that decreases the mosquito population can contain an outbreak. Otherwise, Rift Valley fever is likely to establish itself as a recurring seasonal outbreak. Rift Valley fever poses a potential threat to North America that would require aggressive interventions in order to prevent a recurring seasonal outbreak.