Stabilizing Power Sharing

Power sharing is modeled as a duel over some prize. Each of two players may either share the prize in some ratio or fire at the other player—either in sequence or simultaneously—and eliminate it with a specified probability. If one player eliminates the other without being eliminated itself, it captures the entire prize, but the prize is damaged over time when there is shooting. Simultaneous shooting, which is more damaging than sequential shooting, tends to induce the players to share the prize and expand their opportunities for sharing it. It was effectively implemented by the superpowers with the doctrine of “launch on warning” during the Cold War, and it was strengthened by the development of second-strike capability. Deterring terrorism has proved a different matter, because terrorists are difficult to detect and present few targets that can be damaged.power sharing, game, duel, deterrence, terrorism

What is Power Sharing? Consociationalism, Centripetalism, and Hybrid Power Sharing

In this article, the author analyzes the term "power-sharing" in the context of power exercised within a state. He first examines the term in the very general sense, in which it can be applied to all types and dimensions of sharing of power between various groups and institutional entities. Second, the author examines the meaning of the term in the narrow sense, that is, the phenomenon of systemic sharing of power by groups (segments) whose membership is based on ascribed criteria such as common ancestors, relatives, or racial background, and/or cultural ones such as a common language, religion, or celebrations. The basic segmental units in this sense are nations (understood in the sociological sense), ethnic groups, or religious and denominational communities that form part of divided societies. Third, the article shows the differences between the principal models (types) of power-sharing in the narrow sense: consociationalism, centripetalism, and hybrid power-sharing

Revising Trimbur's Dichotomy: Tutors and Client's Sharing Knowledge, Sharing Power

In the twenty-five years since John Trimbur’s 1987 article, “Peer Tutoring: A Contradiction in Terms?” was published, writing center personnel have found it necessary to emphasize the dichotomy in the term “peer tutor.” Trimbur’s influential article has continually appeared in the literature used to train tutors and introduce them to writing center theory. For example, The Harcourt Brace Guide to Peer Tutoring (1998) and The Longman Guide to Writing Center Theory and Praxis (2008) both include Trimbur’s article. It is also cited in three essays collected in The St. Martin’s Sourcebook for Writing Tutors: Cynthia Haynes-Burton’s “‘Thirty-something’ Students: Concerning Transitions in the Writing Center,” originally published in 1990, Jay Jacoby’s “‘The Use of Force’: Medical Ethics and Center Practice,” and Julie Bokser’s “Peer Tutoring and Gorgias: Acknowledging Aggression in the Writing Center,” originally published in 2001. Each of the articles within The St. Martin’s Sourcebook takes Trimbur’s assertion of the peer-tutor dichotomy as fundamentally true. Training, then, has focused on the task of switching deftly between peer and tutor during a session because it is believed that tutors cannot inhabit both roles simultaneously. Trimbur points out that many tutors feel a loyalty to both the institution that has awarded them the label of “writing expert” as well as to their own peers who share their concerns as students (290-291). Beginning tutors especially will feel pressure from both sides, wanting to please the institution (by passing down knowledge) and their clients (by being co-learners). His solution is to help tutors learn to negotiate conflicting social allegiances through a sequential training module. Toward the end of his article, he worries that “the conception of tutoring as an apprenticeship treats students as extensions of our profession and can reinforce their dependence on faculty authority ” (295). To avoid this situation, Trimbur advocates a developmental tutor training program that would begin by emphasizing the tutor’s role as co-learner in order to de-emphasize the tutor’s belief in the traditional academic paradigm of passing down knowledge from expert to novice.University Writing Cente

The Instability of Power Sharing

Three models are presented in which two players agree to share power in a particular ratio, but either player may subsequently “fire” at the other, as in a duel, to try to eliminate it. The players have positive probabilities of eliminating each other by firing. If neither is successful, the agreement stays in place; if one is successful, that player obtains all the power; if each eliminates the other, both players get nothing. In Model I, the game is played once, and in Model II it is repeated, with discounting of future payoffs. Although there are conditions under which each player would prefer not to shoot, satisfying these conditions for one player precludes satisfying them for the other, so at least one player will always have an incentive to shoot. In anticipation, its rival would prefer to shoot, too, so there will be a race to preempt. In Model III, a damage factor caused by shooting, whether successful or not, is introduced into Model II. This mitigates the incentive to shoot but does not eliminate it entirely. The application of the models to conflicts, especially civil wars, is discussed.power sharing, repeated game, duel, civil wars

Achievable and Crystallized Rate Regions of the Interference Channel with Interference as Noise

The interference channel achievable rate region is presented when the interference is treated as noise. The formulation starts with the 2-user channel, and then extends the results to the n-user case. The rate region is found to be the convex hull of the union of n power control rate regions, where each power control rate region is upperbounded by a (n-1)-dimensional hyper-surface characterized by having one of the transmitters transmitting at full power. The convex hull operation lends itself to a time-sharing operation depending on the convexity behavior of those hyper-surfaces. In order to know when to use time-sharing rather than power control, the paper studies the hyper-surfaces convexity behavior in details for the 2-user channel with specific results pertaining to the symmetric channel. It is observed that most of the achievable rate region can be covered by using simple On/Off binary power control in conjunction with time-sharing. The binary power control creates several corner points in the n-dimensional space. The crystallized rate region, named after its resulting crystal shape, is hence presented as the time-sharing convex hull imposed onto those corner points; thereby offering a viable new perspective of looking at the achievable rate region of the interference channel.Comment: 28 pages, 12 figures, to appear in IEEE Transactions of Wireless Communicatio

The variance of identity-by-descent sharing in the Wright-Fisher model

Widespread sharing of long, identical-by-descent (IBD) genetic segments is a hallmark of populations that have experienced recent genetic drift. Detection of these IBD segments has recently become feasible, enabling a wide range of applications from phasing and imputation to demographic inference. Here, we study the distribution of IBD sharing in the Wright-Fisher model. Specifically, using coalescent theory, we calculate the variance of the total sharing between random pairs of individuals. We then investigate the cohort-averaged sharing: the average total sharing between one individual and the rest of the cohort. We find that for large cohorts, the cohort-averaged sharing is distributed approximately normally. Surprisingly, the variance of this distribution does not vanish even for large cohorts, implying the existence of "hyper-sharing" individuals. The presence of such individuals has consequences for the design of sequencing studies, since, if they are selected for whole-genome sequencing, a larger fraction of the cohort can be subsequently imputed. We calculate the expected gain in power of imputation by IBD, and subsequently, in power to detect an association, when individuals are either randomly selected or specifically chosen to be the hyper-sharing individuals. Using our framework, we also compute the variance of an estimator of the population size that is based on the mean IBD sharing and the variance in the sharing between inbred siblings. Finally, we study IBD sharing in an admixture pulse model, and show that in the Ashkenazi Jewish population the admixture fraction is correlated with the cohort-averaged sharing.Comment: Includes Supplementary Materia

Whakapapa sharing in the context of therapy

Maori experience disproportionately negative outcomes in mental health in New Zealand. The adaptation of therapeutic assessments and interventions to allow more culturally appropriate work with Maori occurs, however, little research promoting an understanding of client’s experience of these adaptations exists. One such adaptation is the sharing of whakapapa (genealogy) between therapist and client. Whakapapa sharing involves a level of therapist self disclosure not yet investigated in psychological literature. This Maori centred analogue study investigates the client’s experience of whakapapa sharing during the first session of therapy. A mixed, between and within subjects design was used, both quantitative and qualitative data were collected and analysed. 30 Maori women between the ages of 18 and 40 participated in two sessions of Acceptance and Commitment Therapy, participants were allocated to either a Whakapapa Sharing group or a Therapist Non-Disclosure group. All participants completed questionnaires measuring the therapeutic alliance, therapy expectancy, outcome of therapy and a cultural questionnaire measuring participant knowledge of their own whakapapa. Participants from the Whakapapa Sharing group also reported on their experience of the sharing. Quantitative analyses revealed no group differences in either the therapeutic relationship measure or the outcome measure. All participants from the Whakapapa Sharing group, regardless of their level of knowledge of their own whakapapa, reported the whakapapa sharing as a positive experience. Further analysis of the qualitative data revealed five main themes; the whakapapa sharing process reported to promote engagement, was perceived as important for Maori, allowed the establishment of connections between therapist and client, provided clients with information with which to form judgements about the therapist and the sharing was seen to be an equitible experience. These themes were arranged into a theoretical model, in which, all five were hypothesised to have a relationship with the power imbalance inherent between therapist and client. Whereby four of the themes were hypothesised to contribute to a decrease in the imbalance of power and the final theme was seen as a result of the decrease in the power imbalance. These tentative findings suggest that the exchange of whakapapa between a therapist and client may serve to decrease the power imbalance in the therapeutic relationship, and as such, it is an appropriate process of engagement in a therapeutic setting with Maori clients, who often experience marginalisation