Charm nonleptonic decays and final state interactions

A global previous analysis of two-body nonleptonic decays of $D$ mesons has been extended to the decays involving light scalar mesons. The allowance for final state interaction also in nonresonant channels provides a fit of much improved quality and with less symmetry breaking in the axial charges. We give predictions for about 50 decay branching ratios yet to be measured. We also discuss long distance contributions to the difference $\Delta \Gamma$ between the $D_S$ and $D_L$ widths.Comment: 14 pages, no figures, plain TeX, uses harvmac.tex and tables.te

Asymptotic behavior of a metapopulation model

We study the behavior of an infinite system of ordinary differential equations modeling the dynamics of a metapopulation, a set of (discrete) populations subject to local catastrophes and connected via migration under a mean field rule; the local population dynamics follow a generalized logistic law. We find a threshold below which all the solutions tend to total extinction of the metapopulation, which is then the only equilibrium; above the threshold, there exists a unique equilibrium with positive population, which, under an additional assumption, is globally attractive. The proofs employ tools from the theories of Markov processes and of dynamical systems.Comment: Published at http://dx.doi.org/10.1214/105051605000000070 in the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

Estimating transmission probability in schools for the 2009 H1N1 influenza pandemic in Italy

BACKGROUND: Epidemic models are being extensively used to understand the main pathways of spread of infectious diseases, and thus to assess control methods. Schools are well known to represent hot spots for epidemic spread; hence, understanding typical patterns of infection transmission within schools is crucial for designing adequate control strategies. The attention that was given to the 2009 A/H1N1pdm09 flu pandemic has made it possible to collect detailed data on the occurrence of influenza-like illness (ILI) symptoms in two primary schools of Trento, Italy. RESULTS: The data collected in the two schools were used to calibrate a discrete-time SIR model, which was designed to estimate the probabilities of influenza transmission within the classes, grades and schools using Markov Chain Monte Carlo (MCMC) methods. We found that the virus was mainly transmitted within class, with lower levels of transmission between students in the same grade and even lower, though not significantly so, among different grades within the schools. We estimated median values of R 0 from the epidemic curves in the two schools of 1.16 and 1.40; on the other hand, we estimated the average number of students infected by the first school case to be 0.85 and 1.09 in the two schools. CONCLUSIONS: The discrepancy between the values of R 0 estimated from the epidemic curve or from the within-school transmission probabilities suggests that household and community transmission played an important role in sustaining the school epidemics. The high probability of infection between students in the same class confirms that targeting within-class transmission is key to controlling the spread of influenza in school settings and, as a consequence, in the general population

The course of cancer related fatigue up to ten years in early breast cancer patients. What impact in clinical practice?

Little is known about the cancer related fatigue (CRF) along cancer course and risk factors that could predict CRF development and persistence in breast cancer (BC) survivors. This prospective study detected incidence, timing of onset, duration of CRF, impact on QoL and psychological distress. Seventy-eight early BC patients, undergoing chemotherapy (CT) followed or not by hormonal therapy were assessed for QoL and psychological distress by EORTC QLQC30 and HADs questionnaires. Fatigue was investigated with mix methods, structured interview and psychometric measures. A qualitative analysis was added to assess the behavioral pattern of CRF. Low fatigue levels were identified after surgery (9%), increasing during (49%) and at the end of CT (47%), maintaining after 1 year (31%) and declining up to ten years of follow-up. Prevalence of CRF was higher at the end of CT and lower at follow-up. At the end and after 1 and 2 years from CT, persistence of CRF was associated to anxiety in 20%, 11% and 5% and to depression in 15%, 10% and 5% respectively. A relationship between CRF and psychological distress was observed; patients presenting depression and anxiety before CT were at higher risk for fatigue onset at a later period. A relationship between fatigue and QoL was noted at the end of CT. Our study shows the fatigue timely trend in early BC patients from surgery, CT and follow-up. Identification of biological, psychological, social predictor factors related to fatigue could be helpful for early interventions in patients at higher risk of developing fatigue

Boards of Directors’ Contribution to Strategy: A Literature Review and Research Agenda

Manuscript Type: Literature review.Research Question/Issue: Over the last four decades, research on the relationship between boards of directors and strategy has proliferated. Yet to date there is little theoretical and empirical agreement regarding the question of how boards of directors contribute to strategy. This review assesses the extant literature by highlighting emerging trends and identifying several avenues for future research.Research Findings/Insights: Using a content-analysis of 150 articles published in 23 manage-ment journals until 2007, we describe and analyze how research on boards of directors and strategy has evolved over time. We illustrate how topics, theories, settings and sources of data interact and influence insights about board-strategy relationships during three specific periods.Theoretical/Academic Implications: Our study illustrates that research on boards of directors and strategy evolved from normative and structural approaches to behavioral and cognitive approaches. Our results encourage future studies (i) to examine the impact of institutional and context-specific factors on the (expected) contribution of boards to strategy, and (ii) to apply alternative methods to fully capture the impact of board processes and dynamics on strategy-making.Practical/Policy Implications: The increasing interest in boards of directors’ contribution to strategy echoes a movement towards more strategic involvement of boards of directors. However, best governance practices and the emphasis on board independence and control may hinder the board contribution to the strategic decision-making. Our study invites investors and policy-makers to consider the requirements for an effective strategic task when they nominee board members and develop new regulations.boards of directors;contribution to strategy;literature review