Incremental closure for systems of two variables per inequality

Subclasses of linear inequalities where each inequality has at most two vari- ables are popular in abstract interpretation and model checking, because they strike a balance between what can be described and what can be efficiently computed. This paper focuses on the TVPI class of inequalities, for which each coefficient of each two variable inequality is unrestricted. An implied TVPI in- equality can be generated from a pair of TVPI inequalities by eliminating a given common variable (echoing resolution on clauses). This operation, called result , can be applied to derive TVPI inequalities which are entailed (implied) by a given TVPI system. The key operation on TVPI is calculating closure: satisfiability can be observed from a closed system and a closed system also simplifies the calculation of other operations. A closed system can be derived by repeatedly applying the result operator. The process of adding a single TVPI inequality to an already closed input TVPI system and then finding the closure of this augmented system is called incremental closure. This too can be calcu- lated by the repeated application of the result operator. This paper studies the calculus defined by result , the structure of result derivations, and how deriva- tions can be combined and controlled. A series of lemmata on derivations are presented that, collectively, provide a pathway for synthesising an algorithm for incremental closure. The complexity of the incremental closure algorithm is analysed and found to be O (( n 2 + m 2 )lg( m )), where n is the number of variables and m the number of inequalities of the input TVPI system

A developmental investigation of the relationship between appraisals and peer self-esteem in children experiencing peer-aggression

Transactional models of stress and coping emphasize the role played by cognitive appraisals in determining psychological adjustment (Lazarus, 1999). This proposition has been supported by research examining young people's adjustment in relation to family conflict and break-up (Grych et al., 1992). Furthermore, this literature suggests that there is a change in the relationship between appraisals and adjustment at around 10 years of age: specificity of appraisal type (e.g. threat, blame) becomes relevant to outcome after 10 years, whereas before 10 there are either no effects of appraisal on adjustment or a diffuse effect of 'negative' appraisals more generally (Jouriles et al., 2000). However, it is currently unclear whether this developmental progression can be generalized from familial- to social-stressors experienced by children and young people. The current study therefore evaluates the model within the context of a commonly experienced social childhood stressor: peer-aggression

Juvenile polyposis syndrome affecting the stomach: A case report

<p>Abstract</p> <p>Introduction</p> <p>Juvenile polyposis syndrome(JPS) is a rare autosomal dominant inherited condition. Hamartomatous polyps can affect the entire gastrointestinal tract but usually predominate in the colon. In this case report we present an unusual case of JPS that presented with massive gastric polyposis requiring a total gastrectomy.</p> <p>Case presentation</p> <p>A 51-year-old man presented with symptoms of gastric outlet obstruction and upper gastrointestinal bleeding. Gastroscopy showed massive gastric polyposis with a large antral polyp that had prolapsed through the pylorus causing gastric outlet obstruction. Initially endoscopic polypectomy was performed, but due to progressive symptoms a total gastrectomy was then performed. Histology confirmed massive gastric juvenile polyposis.</p> <p>Conclusion</p> <p>Massive gastric polyposis is an uncommon manifestation of juvenile polyposis syndrome. This case illustrates important principles in managing this condition.</p

Age Is a Greater Influence on Small Saccades Than Target Size in Normal Subjects on the Horizontal Video Head Impulse Test

Objective: This study sought to investigate whether the size of the target used in the horizontal vHIT has an effect on the saccade profile of healthy subjects, and to expand upon previous work linking age to the existence of small vHIT saccades.Methods: Forty eight participants were recruited between 18 and 77 years of age, with no history of vestibular, oculomotor or neurological conditions and a visual acuity of at least 0.3 LogMAR. Participants underwent four consecutive horizontal vHIT trials using the standard target size and three smaller targets. VOR gain and metrics for saccadic incidence, peak eye velocity and latency were then extracted from results.Results: Target size was a statistically significant influence on saccade metrics. As target size increased, saccadic incidence decreased while peak eye velocity and latency increased. However, a potential order effect was also discovered, and once this was corrected for the remaining effect of target size was small and is likely clinically insignificant. The effect of age was much stronger than target size; increasing age was strongly positively correlated with saccadic incidence and showed a medium size correlation with peak velocity, though not with saccadic latency.Conclusion: While this study suggests that target size may have a statistically significant impact on the vHIT saccade profile of normal subjects, age has a greater influence on the incidence and size of small vHIT saccades

The Inclusion Conundrum: A Critical Account of Youth and Gender Issues Within and Beyond Sport for Development and Peace Interventions

The sport for development and peace (SDP) sector is made up of various development-focused policies and programs that seek to engage, stabilise, empower and create social and economic change. SDP projects, most often run by non-governmental organisations (NGOs), have been implemented in regions enduring physical conflicts, health pandemics, major gender divisions and other social crises that have a great impact on youth. In this context, sport has been accorded the difficult task of facilitating greater access for marginal, vulnerable or community groups whilst positively contributing to the attainment of diverse development objectives. While the ‘where’ and ‘why’ of SDP has been largely accounted for, the attention in this article is on the ‘who’ of SDP in relation to the notion of inclusion. Drawing on extensive research conducted in Jamaica, Kosovo, Rwanda and Sri Lanka, the idea of SDP as an inclusionary practice is critically investigated. While SDP may ‘give voice’ to participants, especially to individuals with athletic ability or sporting interests, the extent to which this creates social contexts that are fundamentally inclusive remains open to discussion. In this sense, while targeting populations, groups or individuals remains an attractive strategy to achieve specific goals, for example youth empowerment or gender equality, empirical assessments complicate the presumption that SDP programming leads to inclusion, particularly at a larger societal level. The article considers a matrix of inclusion criteria, potential outcomes, and the tensions arising between targeted SDP programming and the often-exclusionary dimensions of sport more broadly, with a focus on youth and gender issues

Changes in the characteristics of approved New Drug Applications for antihypertensives

Thesis (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2007.Includes bibliographical references (p. 83-86).In this thesis, the control of hypertension provides the backdrop for my effort to investigate how clinical trial design has evolved for antihypertensive drug submissions reviewed and approved by the Food and Drug Administration between 1988 and 2001. To do this, I have constructed and undertaken a preliminary analysis of a number of quantitative surrogate measures of complexity and scale, such as trial design, numbers of patients, treatment lengths, active drug comparators, number of indications pursued, number of indications approved, and approval times. In addition, I review how practice guidelines for the treatment of hypertension have changed with advancing clinical and biological knowledge. I attempt to investigate whether a link exists between the changing characteristics of clinical trials for antihypertensive therapies and the evolving guidelines for treating hypertension, promulgated by the Joint National Committee Report on the Detection, Evaluation, and Treatment of High Blood Pressure, (JNC), a committee assembled by the National Heart, Lung, and Blood Institute.(cont.) Although the number of New Drug Applications (NDAs) examined in the antihypertensive class is too small to permit rigorous statistical analyses, I am nonetheless able to observe a number of apparent trends within the set of NDA submissions for antihypertensives approved by the FDA. Specific trends I observe in support of increasing trial complexity include: 1) trial sizes increase over time as measured by patient enrollments per trial (p-value = 0.003); 2) clinical trial designs over time have included greater numbers of arms per trial (p-value = 0.022); and 3) the number of drug-drug interaction studies in antihypertensive NDAs has increased with time (p-value = 0.027). These trends offer preliminary support for the hypothesis that clinical trials associated with NDA applications for antihypertensives have become more complex over the last two decades. The mechanisms responsible for the observed increase in complexity are less clear. Based on available information, I cannot determine if FDA guidance documents or informal correspondence were responsible for making antihypertensive clinical trials more complicated, or whether pharmaceutical companies introduced greater complexity into the trial design for commercial reasons.(cont.) Furthermore, while I observe that FDA guidelines did not precisely track changes in JNC guidelines for treating hypertension, it is not clear whether the discrepancies are meaningful. Future research might attempt to identify more precisely the causes of increasing clinical trial complexity, and attempt to relate trial complexity to the cost of drug development more generally.by John Simon Howe MacNeil.S.M

Do coping variables mediate the effect of social identity on psychological wellbeing for bullied children?

Prsentation examining how coping variables mediate the effect of social identity on psychological wellbeing for bullied children. Demonstrates a need to understand how children interpret their situation, not just how they cope with it. This is independent of minority/majority ethnic status