On the Shapley-like Payoff Mechanisms in Peer-Assisted Services with Multiple Content Providers

This paper studies an incentive structure for cooperation and its stability in peer-assisted services when there exist multiple content providers, using a coalition game theoretic approach. We first consider a generalized coalition structure consisting of multiple providers with many assisting peers, where peers assist providers to reduce the operational cost in content distribution. To distribute the profit from cost reduction to players (i.e., providers and peers), we then establish a generalized formula for individual payoffs when a "Shapley-like" payoff mechanism is adopted. We show that the grand coalition is unstable, even when the operational cost functions are concave, which is in sharp contrast to the recently studied case of a single provider where the grand coalition is stable. We also show that irrespective of stability of the grand coalition, there always exist coalition structures which are not convergent to the grand coalition. Our results give us an important insight that a provider does not tend to cooperate with other providers in peer-assisted services, and be separated from them. To further study the case of the separated providers, three examples are presented; (i) underpaid peers, (ii) service monopoly, and (iii) oscillatory coalition structure. Our study opens many new questions such as realistic and efficient incentive structures and the tradeoffs between fairness and individual providers' competition in peer-assisted services.Comment: 13 pages, 4 figures, an extended version of the paper to be presented in ICST GameNets 2011, Shanghai, China, April 201

Pulmonary Kaposi's sarcoma after heart transplantation: a case report

ABSTRACT: INTRODUCTION: Kaposi's sarcomas have been associated with different conditions of immunosuppression and are also known to be a typical complication of solid organ transplantations. CASE PRESENTATION: We report of a 65 year old man of Turkish origin with a history of heart transplantation 10 months ago who presented for clarification of his dyspnoea. The patient had a known history of chronic obstructive pulmonary disease and a smoking history of 40 pack years. Radiologically, three progressively growing intrapulmonary nodules were detected. The histology was diagnostic for a Kaposi's sarcoma. Visceral and especially primary intrapulmonary Kaposi's sarcomas are very rare and have been described to have a rather unfavourable prognosis. CONCLUSION: Even with a history suggestive for conventional lung cancer, Kaposi's sarcomas should be considered in patients after transplantation of solid organs. It should be noticed that in a minority of cases this tumour exists in the absence of the typical cutaneous lesions

The role of educational diversity in investor relations

Purpose: The purpose of this paper is to show the role of educational diversity in improving investor relations (IR) quality and examine how this impacts the number of shareholder activism incidents a firm encounters. Design/methodology/approach: The paper reviews literature on marketing, finance, and corporate communications to develop a conceptual framework which is tested using a combination of secondary data and primary data collected through a survey amongst IR professionals working at companies in the Euronext 100 stock index. Findings: The empirical results support the conceptual framework, showing higher IR quality levels and lower shareholder activism intensity for companies with educationally diverse IR teams. In particular, the presence of marketing and communication experts in IR teams contributes to higher IR quality and lower shareholder activism. Research limitations/implications: Future research may investigate the robustness of the results with larger and internationally diversified samples and examine how, besides educational diversity, other organizational arrangements through which finance professionals work together with marketing and communication professionals impact IR quality. Practical implications: The results suggest that to improve their IR quality and minimize shareholder activism, companies should check and when necessary increase the educational diversity of their IR teams. Originality/value: This is the first paper investigating the role of educational diversity on IR quality and the impact on shareholder activism, developing and testing an innovative conceptual framework that integrates marketing, finance, and corporate communication theory.Arvid O.I. Hoffmann, Aida Tutic and Simone Wie

Volumetry - an alternative to assess therapy response for malignant pleural mesothelioma?

The purpose of this study was to assess robustness of volumetric measurement of malignant pleural mesothelioma (MPM) before and after chemotherapy to modified RECIST. Thirty patients with digitally available chest CT scan before and after 3 cycles of chemotherapy were included. Three readers assessed independently tumour response using two different methods: Modified RECIST criteria and tumour volumetric approach using dedicated software (Myrian, Intrasense, France). Inter-rater reliability of uni-dimensional and volumetric measurements was assessed using intraclass correlation. tumour response classification for modified RECIST was compared to volumetric approach applying uni-dimensional RECIST volumetric equivalent criteria. The determination of uni-dimensional tumour measurement (RECIST) revealed a low inter-rater reliability (0.55) and a low interobserver agreement for tumour response classification (general kappa 0.33). Only 14 patients were classified equally. A high inter-rater reliability (0.99) and interobserver agreement (general kappa 0.9)) was found for absolute tumour volumes (volumetric measurements). 27 cases were classified equally. The number of cases classified as "stable disease" was higher for volumetric approach using tumour equivalent criteria compared to modified RECIST. Volumetric measurement of MPM on CT-scan using Myrian software is a reliable, reproducible and sensitive method to measure tumour volume and hence therapy response after induction chemotherapy

Induction of senescence markers after neo-adjuvant chemotherapy of malignant pleural mesothelioma and association with clinical outcome: an exploratory analysis

The aim of this study was to assess the induction of senescence markers versus apoptosis pathways in malignant pleural mesothelioma (MPM) tumour samples before and after neo-adjuvant platinum-based chemotherapy and to investigate their relationship with clinical outcome. Specific senescence pathways were assessed by quantifying the expression of p21 and plasminogen activator inhibitor-1 (PAI-1) for the p21-p53 pathway, IGFBP7 for the IGF pathway and ALDH1A3 for the IFN pathway. p21 and PAI-1 expression were also assessed by immunohistochemistry. In addition, beta-galactosidase activity staining at pH 6.0 was performed. Apoptosis was determined by TUNEL assay. Clinical outcome was assessed by modified RECIST criteria, progression-free and overall survival. In a training set (n=9 patients) paired comparison demonstrated a significant increase in p21 (p<0.05), PAI-1 (p<0.01) and apoptosis (p<0.01) after neo-adjuvant chemotherapy. The patients with the highest increase in PAI-1 had stable disease, whilst patients with little change in senescence markers accompanied by a high increase in apoptosis had an objective response after chemotherapy. The hypothesis that stable disease might be associated with an increase in senescence markers was confirmed in a tissue microarray (n=26 patients) using p21 and PAI-1 immunohistochemistry as readouts. For patients where survival and time to progression data were available, increased PAI-1 levels were significantly associated with a worst outcome. Our results demonstrate induction of senescence markers by neo-adjuvant chemotherapy in a proportion of patients with MPM and its potential association with a poor outcome

Repeated lung volume reduction surgery is successful in selected patients

OBJECTIVES Lung volume reduction surgery (LVRS) improves dyspnoea, quality of life and may even prolong survival in carefully selected patients with end-stage emphysema. The benefit may be sustained for several years and vanishes with the natural progression of the disease. Data on repeated surgical treatment of emphysema are scarce. The aim of this study was to evaluate the safety, effects and outcomes of repeated LVRS (Re-LVRS) in patients no longer benefiting from their initial LVRS. METHODS Between June 2002 and December 2013, 22 patients (9 females) with advanced emphysema underwent Re-LVRS at a median of 60 months (25–196) after their initial LVRS. While initial LVRS was performed thoracoscopically as a bilateral procedure, Re-LVRS was performed unilaterally by a video-assisted thoracoscopic technique in 19 patients and, due to adhesions, by thoracotomy in 3 patients. Pulmonary function test (PFT) was performed at 3 and 12 months postoperatively. RESULTS Lung function at Re-LVRS was similar to that prior to the first LVRS. The 90-day mortality rate was 0%. The first patient died 15 months postoperatively. The median hospitalization time after Re-LVRS was significantly longer compared with the initial LVRS [14 days, interquartile range (IQR): 11–19, vs 9 days, IQR: 8–14; P = 0.017]. The most frequent complication was prolonged air leak with a median drainage time of 11 days (IQR: 6–13); reoperations due to persistent air leak were necessary in 7 patients (32%). Five patients (23%) had no complications. Lung function and Medical Research Council (MRC) score improved significantly for up to 12 months after Re-LVRS, with results similar to those after initial bilateral LVRS. The average increase in the forced expiratory volume in 1 s (FEV1) was 25% (a 7% increase over the predicted value or 0.18 l) at 3 months, and the mean reduction in hyperinflation, assessed by relative decrease in RV/TLC (residual volume/total lung capacity), was 12% at 3 months (a decrease of 8% in absolute ratios). The mean MRC breathlessness score decreased significantly after 3 months (from 3.7 to 2.2). CONCLUSIONS Re-LVRS can be performed successfully in carefully selected patients as a palliative treatment. It may be performed as a bridge to transplantation or in patients with newly diagnosed intrapulmonary nodules or during elective cardiac surgery. Morbidity is acceptable and outcomes may be satisfactory with significantly improved lung function and reduced dyspnoea for at least 12 months postoperatively

Induction of senescence markers after neo-adjuvant chemotherapy of malignant pleural mesothelioma and association with clinical outcome: An exploratory analysis

The aim of this study was to assess the induction of senescence markers versus apoptosis pathways in malignant pleural mesothelioma (MPM) tumour samples before and after neo-adjuvant platinum-based chemotherapy and to investigate their relationship with clinical outcome. Specific senescence pathways were assessed by quantifying the expression of p21 and plasminogen activator inhibitor-1 (PAI-1) for the p21-p53 pathway, IGFBP7 for the IGF pathway and ALDH1A3 for the IFN pathway. p21 and PAI-1 expression were also assessed by immunohistochemistry. In addition, beta-galactosidase activity staining at pH 6.0 was performed. Apoptosis was determined by TUNEL assay. Clinical outcome was assessed by modified RECIST criteria, progression-free and overall survival. In a training set (n = 9 patients) paired comparison demonstrated a significant increase in p21 (p < 0.05), PAI-1 (p < 0.01) and apoptosis (p < 0.01) after neo-adjuvant chemotherapy. The patients with the highest increase in PAI-1 had stable disease, whilst patients with little change in senescence markers accompanied by a high increase in apoptosis had an objective response after chemotherapy. The hypothesis that stable disease might be associated with an increase in senescence markers was confirmed in a tissue microarray (n = 26 patients) using p21 and PAI-1 immunohistochemistry as readouts. For patients where survival and time to progression data were available, increased PAI-1 levels were significantly associated with a worst outcome. Our results demonstrate induction of senescence markers by neo-adjuvant chemotherapy in a proportion of patients with MPM and its potential association with a poor outcome. © 2010 Elsevier Ltd. All rights reserved

Etiology of solitary extrapulmonary positron emission tomography and computed tomography findings in patients with lung cancer

PURPOSE: The aim of this prospective study was to assess the incidence and the nature of solitary extrapulmonary [18F] fluorodeoxyglucose (FDG) accumulations in patients with non-small-cell lung cancer (NSCLC) staged with integrated positron emission tomography and computed tomography (PET/CT) and to evaluate the impact on management. PATIENTS AND METHODS: A total of 350 patients with NSCLC underwent whole-body PET/CT imaging. All solitary extrapulmonary FDG accumulations were evaluated by histopathology, further imaging, or clinical follow-up. RESULTS: PET/CT imaging revealed extrapulmonary lesions in 110 patients. In 72 patients (21%), solitary lesions were present. A diagnosis was obtained in 69 of these patients, including 37 (54%) with solitary metastases and 32 (46%) with lesions unrelated to the lung primary. Histopathologic examinations of these 32 lesions revealed a second clinically unsuspected malignancy or a recurrence of a previous diagnosed carcinoma in six patients (19%) and a benign tumor or inflammatory lesion in 26 patients (81%). The six malignancies consisted of carcinoma of the breast in two patients, and carcinoma of the orbit, esophagus, prostate, and non-Hodgkin's lymphoma in one patient each. Benign tumors and inflammatory lesions included eight colon adenomas, four Warthin's tumors, one granuloma of the lower jaw, one adenoma of the thyroid gland, one compensatory muscle activity due to vocal chord palsy, two occurrences of arthritis, three occurrences of reflux esophagitis, two occurrences of pancreatitis, two occurrences of diverticulitis, one hemorrhoidal inflammation, and one rib fracture. CONCLUSION: Solitary extrapulmonary FDG accumulations in patients with newly diagnosed lung cancer should be analyzed critically for correct staging and optimal therapy, given that up to half of the lesions may represent unrelated malignancies or benign disease