Water sources of urban trees in the Los Angeles metropolitan area

In semi-arid cities, urban trees are often irrigated, but may also utilize natural water sources such as groundwater. Consequently, the sources of water for urban tree transpiration may be uncertain, complicating efforts to efficiently manage water resources. We used a novel approach based on stable isotopes to determine tree water sources in the Los Angeles basin, where we hypothesized that trees would rely on irrigation water in the soil rather than develop deep roots to tap into groundwater. We evaluated the oxygen (δ¹⁸O) and hydrogen (δD) isotope ratios of xylem water, irrigation water, soil water, and groundwater in a study of temporal patterns in water sources at two urban sites, and a study of spatial patterns at nine urban sites and one “natural” riparian forest. Contrary to our hypothesis, we found that despite frequent irrigation, some trees tap into groundwater, although in most species this was a small water source. Some trees appeared to be using very shallow soil water at <30 cm depth, suggesting that these mature urban trees were quite shallowly rooted. In the natural site, trees appeared to be using urban runoff in addition to shallow soil water. We were able to identify tree uptake of precipitation at only 3 sites. The results show that some irrigated trees utilize groundwater and do not rely solely on irrigation water, which may make them able to withstand drought and/or water conservation measures. However, some irrigated trees may develop very shallow root systems, which may make them more susceptible.     

Infant Distress and Regulatory Behaviors Vary as a Function of Attachment Security Regardless of Emotion Context and Maternal Involvement

Differences in infant distress and regulatory behaviors based on the quality of attachment to mother, emotion context (frustration versus fear), and whether or not mothers were actively involved in the emotion-eliciting tasks were examined in a sample of 98 16-month-old infants and their mothers. Dyads participated in the Strange Situation, a limiting task designed to elicit infant frustration, and a novelty task designed to elicit infant fear. Mothers were asked to remain uninvolved during the first minute of each task, and then instructed to engage with their infants as they wished for the remaining three minutes. Independent of concurrent maternal sensitivity, resistant infants were significantly more distressed than secure and avoidant infants. Avoidant infants engaged in fewer active mother-oriented regulation behaviors than secure and resistant infants and engaged in more self-soothing in the mother involved condition than the mother uninvolved condition. Resistant infants engaged in more physical comfort with their mothers and more venting than both secure and avoidant infants, and exhibited a smaller variety of adaptive non-mother-oriented strategies than did secure infants. There were few differences in infant distress and regulatory behaviors as a function of emotion task and maternal involvement. Limitations and implications for future research are discussed.     

Child Obesity and the Interaction of Family and Neighborhood Socioeconomic Context

Population Research and Policy Review - The literature on neighborhoods and child obesity links contextual conditions to risk, assuming that if place matters, it matters in a similar way for...     

‘They were constantly on the losing side of things’: the pedagogical power of an African-American teacher candidate bearing witness in teacher education

The stories of students and teacher candidates of Color (Just as singular racial/ethnic identities are capitalized (i.e. African-American, Asian, Latina, Native American etc.), I capitalize Color to honor the various identities that many ‘non-white’ people hold near and dear. I recognize the nuances in doing so- such as the reality that the term ‘people of Color’ actually erases identity while the term also highlights a shared experience (though also nuanced) of being ‘non-white’ in a white supremacist society.) hold powerful lessons and insights for teacher education programs and educational reform efforts. Yet, rarely do educators and policy-makers solicit or critically engage the educational narratives of these stakeholders. In particular, research confirms that we know little about how students’ of Color educational experiences are impacted by race(ism) and culture and how those experiences subsequently inform their ideas about teaching. This study, framed by critical race theory (CRT), examines an African-American (African-American is used intentionally here as this is how Ariel identifies racially.) teacher candidate’s racialized K-12 and postsecondary school experiences to more fully understand the connection between lived experience and developing teacher identity. Ariel’s story reflects her own school experiences; her focus on her peers’ school experiences when asked about her own; and how those experiences, informed by race and culture, contribute to her development of pedagogy. Analytical considerations illustrate that memory and remembrance, witnessing and bearing witness, and testimony are deliberate and powerful acts in the development of pedagogy and should be central to teacher education curriculum.     

Improving Expatriation Success: The Roles of Regulatory Focus and Burnout

The study empirically and theoretically contributes to the human resource management discipline by developing and testing a cohesive model drawing on the pertinent literature from expatriate management, burnout and regulatory focus theory. Drawing on data from 233 expatriate managers, the study aims to examine the relationships between expatriate adjustment and the outcomes of job satisfaction and withdrawal cognitions via expatriate burnout. Specifically, the findings reveal that (a) higher levels of both work adjustment and interaction adjustment lead to reduced expatriate burnout, with the former having a greater effect on burnout than the latter; (b) burnout serves as a full mediator between work adjustment and withdrawal cognitions, and a partial mediator between work adjustment and job satisfaction; and (c) regulatory focus serves to moderate expatriate adjustment–outcome consequences, i.e. promotion‐focused (as opposed to prevention‐focused) expatriates demonstrate a stronger burnout–job satisfaction relationship. Several implications are extracted from the study for regulatory theory, burnout and expatriation management practices as well as suggested avenues for future research.     

An integrative model of leadership behavior

Decades of questionnaire and interview studies have revealed various leadership behaviors observed in successful leaders. However, little is known about the actual behaviors that cause those observations. Given that lay observers are prone to cognitive biases, such as the halo effect, the validity of theories that are exclusively based on observed behaviors is questionable. We thus follow the call of leading scientists in the field and derive a parsimonious model of leadership behavior that is informed by established psychological theories. Building on the taxonomy of Yukl (2012), we propose three task-oriented behavior categories (enhancing understanding, strengthening motivation and facilitating implementation) and three relation-oriented behavior categories (fostering coordination, promoting cooperation and activating resources), each of which is further specified by a number of distinct behaviors. While the task-oriented behaviors are directed towards the accomplishment of shared objectives, the relation-oriented behaviors support this process by increasing the coordinated engagement of the team members. Our model contributes to the advancement of leadership behavior theory by (1) consolidating current taxonomies, (2) sharpening behavioral concepts of leadership behavior, (3) specifying precise relationships between those categories and (4) spurring new hypotheses that can be derived from existing findings in the field of psychology. To test our model as well as the hypotheses derived from this model, we advocate the development of new measurements that overcome the limitations associated with questionnaire and interview studies.     

Maximum cardinality neighbourly sets in quadrilateral free graphs

Neighbourly set of a graph is a subset of edges which either share an end point or are joined by an edge of that graph. The maximum cardinality neighbourly set problem is known to be NP-complete for general graphs. Mahdian (Discret Appl Math 118:239–248, 2002) proved that it is in polynomial time for quadrilateral-free graphs and proposed an \(O(n^{11})\) algorithm for the same, here n is the number of vertices in the graph, (along with a note that by a straightforward but lengthy argument it can be proved to be solvable in \(O(n^5)\) running time). In this paper we propose an \(O(n^2)\) time algorithm for finding a maximum cardinality neighbourly set in a quadrilateral-free graph.     

Introducing the expatriate ‘Entry-Mode’: an exploratory qualitative study of a missing link in global mobility and expatriate management research

ABSTRACT

This article introduces the novel concepts of expatriate ‘entry-modes’, ‘comb-patriates’, and ‘Fourth-Country Nationals’ (FCNs), emerging from an exploratory qualitative investigation of 51 Scandinavian expatriates in Hong Kong. Global mobility research has traditionally been overly focused on the characteristics and background variables of expatriates or accumulated experiences after arrival, and has neglected the phase and mode of entering the new host country. Unveiling new global mobility patterns is significant for multinational enterprises’ (MNE) global talent recruitment, and has implications for training and development. This is due to directing the focus towards the increasing numbers of those individuals who are not expatriating in the conventional linear fashion, such as between an MNE’s headquarter (HQ) and its subsidiaries overseas. The critical stance taken in this article is articulated through a theoretical lens comprising a social constructionist epistemology. Theoretical contributions, future research avenues, as well as managerial relevance and policy implications are also discussed.