Improved Bounds for rr-Identifying Codes of the Hex Grid

For any positive integer $r$, an $r$-identifying code on a graph $G$ is a set $C\subset V(G)$ such that for every vertex in $V(G)$, the intersection of the radius-$r$ closed neighborhood with $C$ is nonempty and pairwise distinct. For a finite graph, the density of a code is $|C|/|V(G)|$, which naturally extends to a definition of density in certain infinite graphs which are locally finite. We find a code of density less than $5/(6r)$, which is sparser than the prior best construction which has density approximately $8/(9r)$.Comment: 12p

Characterizing extremal digraphs for identifying codes and extremal cases of Bondy's theorem on induced subsets

An identifying code of a (di)graph $G$ is a dominating subset $C$ of the vertices of $G$ such that all distinct vertices of $G$ have distinct (in)neighbourhoods within $C$. In this paper, we classify all finite digraphs which only admit their whole vertex set in any identifying code. We also classify all such infinite oriented graphs. Furthermore, by relating this concept to a well known theorem of A. Bondy on set systems we classify the extremal cases for this theorem

An improved lower bound for (1,<=2)-identifying codes in the king grid

We call a subset $C$ of vertices of a graph $G$ a $(1,\leq \ell)$-identifying code if for all subsets $X$ of vertices with size at most $\ell$, the sets $\{c\in C |\exists u \in X, d(u,c)\leq 1\}$ are distinct. The concept of identifying codes was introduced in 1998 by Karpovsky, Chakrabarty and Levitin. Identifying codes have been studied in various grids. In particular, it has been shown that there exists a $(1,\leq 2)$-identifying code in the king grid with density 3/7 and that there are no such identifying codes with density smaller than 5/12. Using a suitable frame and a discharging procedure, we improve the lower bound by showing that any $(1,\leq 2)$-identifying code of the king grid has density at least 47/111

Communication and trust in the bounded confidence model

The communication process in a situation of emergency is discussed within the Scheff theory of shame and pride. The communication involves messages from media and from other persons. Three strategies are considered: selfish (to contact friends), collective (to join other people) and passive (to do nothing). We show that the pure selfish strategy cannot be evolutionarily stable. The main result is that the community structure is statistically meaningful only if the interpersonal communication is weak.Comment: 6 pages, 5 figures, RevTeX, for ICCCI-201

A Model for the Development of the Rhizobial and Arbuscular Mycorrhizal Symbioses in Legumes and Its Use to Understand the Roles of Ethylene in the Establishment of these two Symbioses

We propose a model depicting the development of nodulation and arbuscular mycorrhizae. Both processes are dissected into many steps, using Pisum sativum L. nodulation mutants as a guideline. For nodulation, we distinguish two main developmental programs, one epidermal and one cortical. Whereas Nod factors alone affect the cortical program, bacteria are required to trigger the epidermal events. We propose that the two programs of the rhizobial symbiosis evolved separately and that, over time, they came to function together. The distinction between these two programs does not exist for arbuscular mycorrhizae development despite events occurring in both root tissues. Mutations that affect both symbioses are restricted to the epidermal program. We propose here sites of action and potential roles for ethylene during the formation of the two symbioses with a specific hypothesis for nodule organogenesis. Assuming the epidermis does not make ethylene, the microsymbionts probably first encounter a regulatory level of ethylene at the epidermis–outermost cortical cell layer interface. Depending on the hormone concentrations there, infection will either progress or be blocked. In the former case, ethylene affects the cortex cytoskeleton, allowing reorganization that facilitates infection; in the latter case, ethylene acts on several enzymes that interfere with infection thread growth, causing it to abort. Throughout this review, the difficulty of generalizing the roles of ethylene is emphasized and numerous examples are given to demonstrate the diversity that exists in plants

Symbolic meanings and e-learning in the workplace: The case of an intranet-based training tool

This article contributes to the debate on work-based e-learning, by unpacking the notion of ‘the learning context’ in a case where the mediating tool for training also supports everyday work. Users’ engagement with the information and communication technology tool is shown to reflect dynamic interactions among the individual, peer group, organizational and institutional levels. Also influential are professionals’ values and identity work, alongside their interpretations of espoused and emerging symbolic meanings. Discussion draws on pedagogically informed studies of e-learning and the wider organizational learning literature. More centrally, this article highlights the instrumentality of symbolic interactionism for e-learning research and explores some of the framework’s conceptual resources as applied to organizational analysis and e-learning design. </jats:p

Clinical realism: a new literary genre and a potential tool for encouraging empathy in medical students

Background: Empathy has been re-discovered as a desirable quality in doctors. A number of approaches using the medical humanities have been advocated to teach empathy to medical students. This paper describes a new approach using the medium of creative writing and a new narrative genre: clinical realism. Methods: Third year students were offered a four week long Student Selected Component (SSC) in Narrative Medicine and Creative Writing. The creative writing element included researching and creating a character with a life-changing physical disorder without making the disorder the focus of the writing. The age, gender, social circumstances and physical disorder of a character were randomly allocated to each student. The students wrote repeated assignments in the first person, writing as their character and including details of living with the disorder in all of their narratives. This article is based on the work produced by the 2013 cohort of students taking the course, and on their reflections on the process of creating their characters. Their output was analysed thematically using a constructivist approach to meaning making. Results: This preliminary analysis suggests that the students created convincing and detailed narratives which included rich information about living with a chronic disorder. Although the writing assignments were generic, they introduced a number of themes relating to illness, including stigma, personal identity and narrative wreckage. Some students reported that they found it difficult to relate to “their” character initially, but their empathy for the character increased as the SSC progressed. Conclusion: Clinical realism combined with repeated writing exercises about the same character is a potential tool for helping to develop empathy in medical students and merits further investigation

Making space for empathy: supporting doctors in the emotional labour of clinical care

BACKGROUND: The academic and medical literature highlights the positive effects of empathy for patient care. Yet, very little attention has been given to the impact of the requirement for empathy on the physicians themselves and on their emotional wellbeing. DISCUSSION: The medical profession requires doctors to be both clinically competent and empathetic towards the patients. In practice, accommodating both requirements can be difficult for physicians. The image of the technically skilful, rational, and emotionally detached doctor dominates the profession, and inhibits physicians from engaging emotionally with their patients and their own feelings, which forms the basis for empathy. This inhibition has a negative impact not only on the patients but also on the physicians. The expression of emotions in medical practice is perceived as unprofessional and many doctors learn to supress and ignore their feelings. When facing stressful situations, these physicians are more likely to suffer from depression and burnout than those who engage with and reflect on their feelings. Physicians should be supported in their emotional work, which will help them develop empathy. Methods could include questionnaires that aid self-reflection, and discussion groups with peers and supervisors on emotional experiences. Yet, in order for these methods to work, the negative image associated with the expression of emotions should be questioned. Also, the work conditions of physicians should improve to allow them to make use of these tools. SUMMARY: Empathy should not only be expected from doctors but should be actively promoted, assisted and cultivated in the medical profession