Games With General Coalitional Structure

Abstract: This paper introduces a new solution concept for cooperative games with general coalitional structure in which only certain sets of players, including the set of all players, are able to form feasible coalitions. The solution concept takes into account the marginal contribution of players. This marginal contribution can be a joint contribution of several players and is equally divided among those players. Any set system representing a coalitional structure induces a collection of coalitional trees, whose nodes may consist of subsets of players. As solution we take the average of the marginal contribution vectors that correspond to all coalitional trees. The solution is ecient and several other properties are studied and some special cases are considered.

The Average Covering Tree Value for Directed Graph Games

We introduce a single-valued solution concept, the so-called average covering tree value, for the class of transferable utility games with limited communication structure represented by a directed graph. The solution is the average of the marginal contribution vectors corresponding to all covering trees of the directed graph. The covering trees of a directed graph are those (rooted) trees on the set of players that preserve the dominance relations between the players prescribed by the directed graph. The average covering tree value is component efficient and under a particular convexity-type condition is stable. For transferable utility games with complete communication structure the average covering tree value equals to the Shapley value of the game. If the graph is the directed analog of an undirected graph the average covering tree value coincides with the gravity center solution

ERKEN UYARI SISTEMLERÝ YOLUYLA TURKIYE’DEKI EKONOMIK KRIZLERIN ANALIZI

It is observed that the interest rate-exchange rate nexus in the Turkish economy appeared in the process of financial liberalization has formed a fragile structure and that this situation has triggered the economic crises along with the rising of the country’s risk premium. In this context, the attentions have been drawn up on the crises which were led by the artificial welfare increases created by the gap between interest rate and exchange rate, and up on the unsustainability of artificially appreciated national currency with high interest rates in the economy.Economic crises, Currency-balance of payment crises, Financial-banking crises, Early warning systems, exchange rate pressure index, Turkish economy, Logit model, Probit model

Impact of SARS-CoV-2 on training and mental well-being of surgical gynecological oncology trainees

Introduction: The SARS-CoV-2 global pandemic has caused a crisis disrupting health systems worldwide. While efforts are being made to determine the extent of the disruption, the impact on gynecological oncology trainees/training has not been explored. We conducted an international survey of the impact of SARS-CoV-2 on clinical practice, medical education, and mental well-being of surgical gynecological oncology trainees. Methods: In our cross-sectional study, a customized web-based survey was circulated to surgical gynecological oncology trainees from national/international organizations from May to November 2020. Validated questionnaires assessed mental well-being. The Wilcoxon rank-sum test and Fisher's exact test were used to analyse differences in means and proportions. Multiple linear regression was used to evaluate the effect of variables on psychological/mental well-being outcomes. Outcomes included clinical practice, medical education, anxiety and depression, distress, and mental well-being. Results: A total of 127 trainees from 34 countries responded. Of these, 52% (66/127) were from countries with national training programs (UK/USA/Netherlands/Canada/Australia) and 48% (61/127) from countries with no national training programs. Altogether, 28% (35/125) had suspected/confirmed COVID-19, 28% (35/125) experienced a fall in household income, 20% (18/90) were self-isolated from households, 45% (57/126) had to re-use personal protective equipment, and 22% (28/126) purchased their own. In total, 32.3% (41/127) of trainees (16.6% (11/66) from countries with a national training program vs 49.1% (30/61) from countries with no national training program, p=0.02) perceived they would require additional time to complete their training fellowship. The additional training time anticipated did not differ between trainees from countries with or without national training programs (p=0.11) or trainees at the beginning or end of their fellowship (p=0.12). Surgical exposure was reduced for 50% of trainees. Departmental teaching continued throughout the pandemic for 69% (87/126) of trainees, although at reduced frequency for 16.1% (14/87), and virtually for 88.5% (77/87). Trainees reporting adequate pastoral support (defined as allocation of a dedicated mentor/access to occupational health support services) had better mental well-being with lower levels of anxiety/depression (p=0.02) and distress (p<0.001). Trainees from countries with a national training program experienced higher levels of distress (p=0.01). Mean (SD) pre-pandemic mental well-being scores were significantly higher than post-pandemic scores (8.3 (1.6) vs 7 (1.8); p<0.01). Conclusion: SARS-CoV-2 has negatively impacted the surgical training, household income, and psychological/mental well-being of surgical gynecological oncology trainees. The overall clinical impact was worse for trainees in countries with no national training program than for those in countries with a national training program, although national training program trainees reported greater distress. COVID-19 sickness increased anxiety/depression. The recovery phase must focus on improving mental well-being and addressing lost training opportunities

Selective manipulation of ICT and PET processes in styryl-bodipy derivatives: Applications in molecular logic and fluorescence sensing of metal ions

Remarkably versatile chemistry of Bodipy dyes allows the design and straightforward synthesis of multivalent-multitopic derivatives, which, with judicious selection of metal ion-ligand pairs based on known affinities, affords control and manipulation of photoinduced electron transfer and internal charge transfer processes as desired. We have demonstrated that metal ions acting as modulators (or inputs, in digital design parlance) can generate absorbance changes in accordance with the operation of a half-adder. In addition, an AND logic gate in the emission mode was delivered using a different binucleating arrangement of ligands. A molecular equivalent of a three-input AND logic gate was also obtained exploiting differential binding affinities of metal ions for different ligands. The results suggest that different metal ions can be used as nonannihilating inputs, selectively targeting various ligands incorporated within a single fluorophore, and with careful design, diverse photophysical processes can be selectively modulated, resulting in a range of signals, useful in molecular logic design, and offering an enticing potential for multianalyte chemosensors. © 2010 American Chemical Society

Feelings of burden among family caregivers of people with spinal cord injury in Turkey

Study design: The study was designed as a cross-sectional survey. Objectives: The purpose of the study was to examine the level of feelings of burden in family caregivers of people with spinal cord injury (SCI) in Turkey, and to explore its predictors. Setting: Turkey. Methods: One hundred family caregivers of people with SCI completed measures of burden of caregiving, depression, social support and physical health. The SCI participants completed a measure of functional independence. Multivariate statistics and structural equation modeling (SEM) were conducted to identify significant predictors of caregiver burden. Results: Caregiver burden was significantly related to caregivers’ feelings of depression. SEM analysis showed that social support from family and from friends predicted caregiver burden via depression. Caregivers’ age, sex, educational level, physical health and household income did not significantly predict their feelings of depression or burden. Conclusions: Our findings revealed that support received from both families and friends is an important source for alleviating the depressive feelings of caregivers and, in return, their burden in the caregiving. In Turkey, high support from family members is expected and is important for psychological well-being, yet the current study showed that the support received from friends also has unique contribution to the well-being of the caregivers of persons with SCI. Overall, our findings highlight the importance of supportive relationships between family as well as friends for the caregivers who may have to provide lifetime care for their family member with special needs.WOS:000407265700012Scopus - Affiliation ID: 60105072PMID: 28169295Science Citation Index Expanded - Social Sciences Citation IndexQ2 - Q3ArticleUluslararası işbirliği ile yapılan - EVETAğustos2017YÖK - 2016-1

Dose dependent effect of statins on postoperative atrial fibrillation after cardiac surgery among patients treated with beta blockers

<p>Abstract</p> <p>Background</p> <p>Previous studies on the effects of Statins in preventing atrial fibrillation (AF) after cardiac surgery have shown conflicting results. Whether statins prevent AF in patients treated with postoperative beta blockers and whether the statin-effect is dose related are unknown.</p> <p>Methods</p> <p>We retrospectively studied 1936 consecutive patients who underwent coronary artery bypass graft (CABG) (n = 1493) or valve surgery (n = 443) at the Minneapolis Veterans Affairs Medical Center. All patients were in sinus rhythm before the surgery. Postoperative beta blockers were administered routinely (92% within 24 hours postoperatively).</p> <p>Results</p> <p>Mean age was 66+10 years and 68% of the patients were taking Statins. Postoperative AF occurred in 588 (30%) patients and led to longer length of stay in the intensive care unit versus those without AF (5.1+7.6 days versus 2.5+2.3 days, p < 0.0001). Patients with a past history of AF had a 5 times higher risk of postoperative AF (odds ratio 5.1; 95% confidence interval 3.4 to 7.7; p < 0.0001). AF occurred in 31% of patients taking statins versus 29% of the others (p = 0.49). In multivariable analysis, statins were not associated with AF (odds ratio (OR) 0.93, 95% confidence interval (CI) 0.7 to 1.2; p = 0.59). However, in a subgroup analysis, the patients treated with Simvastatin >20 mg daily had a 36% reduction in the risk of postoperative AF (OR 0.64, 95% CI 0.43 to 0.6; p = 0.03) in comparison to those taking lower dosages.</p> <p>Conclusion</p> <p>Among cardiac surgery patients treated with postoperative beta blockers Statin treatment reduces the incidence of postoperative AF when used at higher dosages</p