Dark matter scenarios in the minimal SUSY B-L model

We perform a study of the dark matter candidates of a constrained version of the minimal R-parity-conserving supersymmetric model with a gauged $U(1)_{B-L}$. It turns out that there are four additional candidates for dark matter in comparison to the MSSM: two kinds of neutralino, which either correspond to the gaugino of the $U(1)_{B-L}$ or to a fermionic bilepton, as well as "right-handed" CP-even and -odd sneutrinos. The correct dark matter relic density of the neutralinos can be obtained due to different mechanisms including new co-annihilation regions and resonances. The large additional Yukawa couplings required to break the $U(1)_{B-L}$ radiatively often lead to large annihilation cross sections for the sneutrinos. The correct treatment of gauge kinetic mixing is crucial to the success of some scenarios. All candidates are consistent with the exclusion limits of Xenon100.Comment: 45 pages, 22 figures; v2: extended discussion of direct detection cross section, matches published versio

Psychosocial factors during the first year after a coronary heart disease event in cases and referents. Secondary Prevention in Uppsala Primary Health Care Project (SUPRIM)

<p>Abstract</p> <p>Background</p> <p>A large number of studies have reported on the psychosocial risk factor pattern prior to coronary heart disease events, but few have investigated the situation during the first year after an event, and none has been controlled. We therefore performed a case-referent study in which the prevalence of a number of psychosocial factors was evaluated.</p> <p>Methods</p> <p>Three hundred and forty-six coronary heart disease male and female cases no more than 75 years of age, discharged from hospital within the past 12 months, and 1038 referents from the general population, matched to the cases by age, sex and place of living, received a postal questionnaire in which information on lifestyle, psychosocial and quality of life measures were sought.</p> <p>Results</p> <p>The cases were, as expected, on sick leave to a larger extent than the referents, reported poorer fitness, poorer perceived health, fewer leisure time activities, but unexpectedly reported better social support, and more optimistic views of the future than the referents. There were no significant case-referent differences in everyday life stress, stressful life events, vital exhaustion, depressive mood, coping or life orientation test. However, women reported less favourable situations than men regarding stressful life events affecting others, vital exhaustion, depressive mood, coping, self-esteem, sleep, and symptom reporting, and female cases reported the most unfavourable situation of all groups.</p> <p>Conclusion</p> <p>In this first controlled study of the situation during the first year after a CHD event disease and gender status both appeared to be determinants of psychological well-being, with gender status apparently the strongest. This may have implications for cardiac rehabilitation programmes.</p

A method for comparing intra-tumoural radioactivity uptake heterogeneity in preclinical positron emission tomography studies

BACKGROUND: Non-uniformity influences the interpretation of nuclear medicine based images and consequently their use in treatment planning and monitoring. However, no standardised method for evaluating and ranking heterogeneity exists. Here, we have developed a general algorithm that provides a ranking and a visualisation of the heterogeneity in small animal positron emission tomography (PET) images. METHODS: The code of the algorithm was written using the Matrix Laboratory software (MATLAB). Parameters known to influence the heterogeneity (distances between deviating peaks, gradients and size compensations) were incorporated into the algorithm. All data matrices were mathematically constructed in the same format with the aim of maintaining overview and control. Histograms visualising the spread and frequency of contributions to the heterogeneity were also generated. The construction of the algorithm was tested using mathematically generated matrices and by varying post-processing parameters. It was subsequently applied in comparisons of radiotracer uptake in preclinical images in human head and neck carcinoma and endothelial and ovarian carcinoma xenografts. RESULTS: Using the developed algorithm, entire tissue volumes could be assessed and gradients could be handled in an indirect manner. Similar-sized volumes could be compared without modifying the algorithm. Analyses of the distribution of different tracers gave results that were generally in accordance with single plane preclinical images, indicating that it could appropriately handle comparisons of targeting vs. non-targeting tracers and also for different target levels. Altering the reconstruction algorithm, pixel size, tumour ROI volumes and lower cut-off limits affected the calculated heterogeneity factors in expected directions but did not reverse conclusions about which tumour was more or less heterogeneous. CONCLUSIONS: The algorithm constructed is an objective and potentially user-friendly tool for one-to-one comparisons of heterogeneity in whole similar-sized tumour volumes in PET imaging

IMPELLA COMPARED TO VENOARTERIAL EXTRACORPOREAL MEMBRANE OXYGENATION IN CARDIOGENIC SHOCK: A SYSTEMATIC REVIEW AND META-ANALYSIS OF PROPENSITY SCORE-MATCHED STUDIES

Background: Veno-arterial extracorporeal membrane oxygenation (VA ECMO) and Impella, a transluminal microaxial ventricular assist device, are well-established in the management of cardiogenic shock. No randomized controlled trials (RCTs) directly compare Impella versus VA ECMO to inform their safety and efficacy in cardiogenic shock. Purpose: This study aims to conduct a systematic review and meta-analysis of propensity score-matched/adjusted studies to compare the clinical outcomes of Impella versus VA ECMO in cardiogenic shock patients. Methods: A systematic review was undertaken to identify comparative studies of Impella and VA ECMO in cardiogenic shock, which in the absence of RCTs, was limited to observational trials with propensity-matched or adjusted outcomes to account for important confounding factors between populations. In-hospital/30-day survival and bleeding events requiring transfusion were meta-analyzed using the random effects method. Results: Five propensity score-matched/adjusted studies comparing short-term survival following treatment with Impella versus VA ECMO were included. A statistically significant difference in in-hospital/30-day mortality was detected between patients treated with Impella (39.6%) versus VA ECMO (53.8%) (odds ratio [95% confidence interval]: 0.57 [0.44, 0.74]; P < 0.0001). Impella was associated with significantly fewer bleeding events requiring transfusion compared with VA ECMO (19.9% vs. 28.8%, respectively) (OR [95% confidence interval]: 0.61 [0.46, 0.80]; P = 0.0004). Conclusion: In the absence of RCTs, this meta-analysis of propensity matched/adjusted observational trials represents the highest level of evidence available to date. Impella was associated with improved short-term survival and decreased bleeding events compared to VA ECMO in patients with cardiogenic shock

Distributed leadership in higher education: what does it accomplish?

Author's draft; final version published in Leadership. Available on http://online.sagepub.com/The term ‘distributed leadership’ has been prominent in research into educational management for some time. A number of articles have recently questioned the explanatory utility of the concept; in this essay we examine its rhetorical function in higher education institutions. We suggest that it has served to contain and to some extent ameliorate two contradictions in the experience of academics who take on managerial roles or who exert leadership of some sort. Firstly, it may help to make sense of a contrast between their experience of leadership and their sense of what it should be; secondly, it helps to mediate conflicts in the identity-work of being an academic and a manager. Also, placed in the wider context of changes in the cultures of universities, ‘distributed leadership’ may mask the concentration of influence with those who have control of budgets, threats to traditional means of upward communication, and the predominance of academic leadership. We conclude that the term ‘distributed leadership’ draws attention to the large number of actors involved in leadership, and the importance of organizational processes in shaping their engagements, but has limited use as an analytical heuristic. However it has a number of rhetorical functions that make a significant contribution to the ways in which leadership is accomplished in sectors such as Higher Education