13 sonuçlar
Arama Sonuçları
Listeleniyor 1 - 10 / 13
Yayın A stochastic risk-averse framework for blood donation appointment scheduling under uncertain donor arrivals(Springer, 2020-12) Yalçındağ, Semih; Baş Güre, Seda; Carello, Giuliana; Lanzarone, EttoreBlood is a key resource in all health care systems, usually drawn from voluntary donors. We focus on the operations management in blood collection centers, which is a key step to guarantee an adequate blood supply and a good quality of service to donors, by addressing the so-called Blood Donation Appointment Scheduling problem. Its goal is to employ appointment scheduling to balance the production of blood units between days, in order to provide a reasonably constant supply to transfusion centers and hospitals, and reduce non-alignments between physicians' working times and donor arrivals at the collection center. We consider a two-phase solution framework taken from the literature, in which a deterministic linear programming model preallocates time slots to different blood types and a prioritization policy assigns the preallocated slots to the donors when they make a reservation. However, the problem is stochastic in nature and requires consideration of the uncertain arrivals of non-booked donors. In this work, to include the uncertain arrivals, we propose three stochastic counterparts of the preallocation model based on a risk-neutral objective and two risk-averse objectives, respectively, where the Conditional Value-at-Risk is considered as the risk measure in the last two methods. The resulting stochastic frameworks have been tested considering the historical data of one of the largest Italian collection centers, the Milan Department of the "Associazione Volontari Italiani Sangue" (AVIS). Results show the effectiveness of the stochastic models, especially the mean-risk one, and the need to include the uncertainty of arrivals in order to better balance the production of blood units.Yayın Imagined contact facilitates acculturation, sometimes: contradicting evidence from two sociocultural contexts(Educational Publishing Foundation-American Psychological Assoc, 2019-10) Bağcı Hemşinlioğlu, Sabahat Çiğdem; Piyale, Zeynep Ecem; Stathi, SofiaObjective: Imagined intergroup contact has been shown to be an effective tool to improve intergroup relationships in various settings, yet the application of the strategy among minority group members and across cultures has been scarce. The current research aimed to test imagined contact effects on minority group members' acculturation strategies (contact participation and culture maintenance), perceived discrimination, feelings of belongingness, and social acceptance across three studies conducted in the United Kingdom (Study 1) and Turkey (Studies 2 and 3). Method: The sample consisted of Eastern Europeans in Study 1 (N = 63) and Kurds in Study 2 and 3 (N = 66 and 210, respectively). Participants were randomly assigned to 1 of 2 conditions (control vs. imagined contact) and completed measures of acculturation, perceived discrimination, general belongingness, and social acceptance. Results: Findings showed that while imagined contact significantly reduced perceived discrimination and culture maintenance, and increased contact participation and social acceptance among Eastern Europeans (Study 1), it reduced social acceptance and contact participation among Kurds recruited from a conflict-ridden homogeneous setting (Study 2). With a larger and more heterogeneous sample of Kurds (Study 3), these effects occurred only among those with higher ingroup identification. Moreover, in all studies social acceptance mediated the effects of imagined contact on contact participation and perceived discrimination. Discussion. Findings offer important insights about the use of the imagined contact strategy among minority group members and imply the need to take into account the context-dependent nature of contact strategies.Yayın Investigating the role of E-contact and self-disclosure on improving Turkish-Kurdish interethnic relations(Wiley, 2021-06) Bağcı Hemşinlioğlu, Sabahat Çiğdem; Güvensoy, İpek; Turner, Rhiannon; White, Fiona Ann; Piyale, Zeynep EcemWhile recent research has started to pay more attention to the role of contact strategies on promoting intergroup harmony between Turkish and Kurdish communities, the effectiveness of a novel form of indirect contact strategy, E-contact—where participants engage in a cooperative and structured online interaction with an individual from the outgroup—has not yet been tested. Across two studies (NStudy 1 = 110, NStudy 2 = 176), we investigated the effects of E-contact among Turks on promoting positive attitudes and behavioral tendencies toward Kurds, testing outgroup trust and intergroup anxiety as mediators and incorporating a distinction between lower and higher self-disclosure conditions. As expected, E-contact led to more positive outgroup attitudes, as well as greater approach tendencies and decreased avoidance tendencies through increased outgroup trust (Studies 1 and 2) and reduced intergroup anxiety (Study 2). Study 2 also found that E-contact produced lower perceived interethnic conflict through increased outgroup trust. While both lower and higher personal disclosure conditions provided similar effects in the two studies, E-contact with heightened self-disclosure was especially effective at promoting more positive outgroup attitudes and reducing avoidance tendencies. Findings highlight potential benefits of using E-contact as a prejudice-reduction strategy in conflict settings.Yayın Collective victimhood beliefs among majority and minority groups: Links to ingroup and outgroup attitudes and attribution of responsibility for conflict(Pergamon-Elsevier Science Ltd, 2018-09) Bağcı Hemşinlioğlu, Sabahat Çiğdem; Piyale, Zeynep Ecem; Karaköse Çelik, Selin; Şen, EzgiWe examined perceived ingroup and outgroup victimhood beliefs across group status and how these were uniquely associated with ingroup and outgroup attitudes and attribution of responsibility among majority (Turkish, N = 141) and minority (Kurdish, N = 86) group members in Turkey. We further explored whether the extent to which collective victimhood beliefs were shared via ingroup and outgroup members predicted our dependent measures beyond the subjective perception of ingroup victimhood. Findings showed that both groups perceived higher ingroup victimhood compared to outgroup victimhood and this difference was more pronounced among the minority group. Perceived outgroup victimhood beliefs, compared to ingroup victimhood beliefs, were more closely related to intergroup outcomes, and led to more positive outgroup and more negative ingroup outcomes. Both groups shared collective victimhood beliefs more with their ingroup friends than their outgroup friends and ingroup sharing of collective victimhood was a stronger predictor of intergroup outcomes, relating to more positive ingroup and more negative outgroup outcomes. Outgroup sharing of collective victimhood was related to more positive outgroup attitudes and lower ingroup responsibility among the Turkish group, whereas it was not related to outgroup attitudes and negatively related to ingroup attribution of responsibility among the Kurdish group. Practical and theoretical implications of the findings were discussed.Yayın Pedestrian crossing behavior at midblock crosswalks(Elsevier Ltd, 2019-12) Tezcan, Hüseyin Onur; Elmorssy, Mahmoud; Aksoy, GökerIntroduction: This study investigated the pedestrian crossing behavior at midblock crosswalks, in Istanbul. Method: Data were compiled from field studies at four selected crosswalks that were on one-way streets. Three of the crosswalks were located on three-lane streets while the other one was on a two-lane street. By using two-hour video recordings at each crosswalk, information was collected about pedestrian crossing preferences, pedestrian platoons both at curbside and during the crossing, traffic characteristics including volume, crosswalk occupancy and illegal parking, and pedestrian characteristics comprising age, gender and distraction status. These data were stratified with respect to the number of lanes and two multinomial logit models for platooning and individual crossing behavior was estimated for each stratum. Results: The results showed that the likelihood of platooning increases as the traffic volume and platoon size increase. Moreover, pedestrians who waited for little or no at the curbside and started to cross when one or more lanes were occupied generally lost time during the crossing. In terms of policy, the formation of platoons should be prevented by enforcement or demand-responsive traffic signals with push-to-walk buttons, etc. Overall, the study revealed that the presence of midblock crosswalks is questionable.Yayın Group efficacy as a moderator on the associations between perceived discrimination, acculturation orientations, and psychological well-being(Wiley, 2020-01-01) Bağcı Hemşinlioğlu, Sabahat Çiğdem; Canpolat, EsraWe investigated whether associations between perceived discrimination (PD), acculturation orientations (desire for culture maintenance and desire for contact), and well-being (psychological well-being and life satisfaction) were moderated by group efficacy beliefs-the extent to which group members believe in their ability to achieve social change collectively. We recruited 163 Syrian refugees (M-age = 36.43, SD = 12.68; 88 females and 75 males) from a south-eastern city in Turkey. PD was negatively associated with desire for culture maintenance and positively associated with desire for contact, indicating an assimilation trend as a response to PD. Both acculturation orientations in turn predicted well-being positively. However, the ones with higher group efficacy did not experience the detrimental effects of PD on well-being and indicated a stronger desire for contacting mainstream society. Further conditional indirect effects demonstrated that only among the ones with lower group efficacy, PD was related to lower psychological well-being through reduced culture maintenance. Findings indicate the critical role of group efficacy beliefs in the understanding of disadvantaged group members' reactions to PD.Yayın Anti-tobacco control industry strategies in Turkey(BioMed Central Ltd, 2018-02-26) Keklik, Seda; Gültekin Karakas, DeryaBackground: Transnational tobacco companies (TTCs) penetrated the Turkish cigarette market due to trade and investment liberalization in the post-1980 period and eventually secured full control. Despite tobacco control policies put in place in reaction to accelerating consumption, TTCs reinforced their market power through a variety of strategies. This paper explores industry strategies that counteract tobacco control policies in Turkey. Methods: The study employs both qualitative and quantitative analyses to explore industry strategies in Turkey. Besides the content analyses of industry and market reports, descriptive analyses were conducted for the sub-periods of 1999-2015. The analyses focus on the market strategies of product innovation, advertisement-promotion, cost management and pricing. Results: Rising sales of low tar, ultra-low tar, slim, super-slim and flavoured cigarettes indicate that product innovation served to sustain consumption. Besides, the tobacco industry, using its strong distribution channels, the Internet, and CSR projects, were found to have promoted smoking indirectly. The industry also rationalized manufacturing facilities and reduced the cost of tobacco, making Turkey a cigarette-manufacturing base. Tobacco manufacturers, moreover, offered cigarettes in different price segments and adjusted net prices both up and down according to price categories and market conditions. In response to the successful effect of shifts in price margins, the market share of mid-priced cigarettes expanded while those within the economy category maintained the highest market share. As a result of pricing strategies, net sales revenues increased. Aside from official cigarette sales, the upward trends in the registered and unregistered sales of cigarette substitutes indicate that the demand-side tobacco control efforts remain inadequate. Conclusions: The Turkish case reveals that the resilience of the tobacco industry vis-a-vis mainstream tobacco control efforts necessitates a new policy perspective. Rising market concentration by TTCs and the global nature of industry strategies require that the highly profitable manufacturing and trade of tobacco products should be discouraged on a basis of international collaboration. To reduce and eventually eradicate tobacco consumption, supply-side tobacco control measures are needed along with demand-side policies.Yayın Imagined contact in high conflict settings: The role of ethnic group identification and the perspective of minority group members(Wiley, 2018-01) Bağcı Hemşinlioğlu, Sabahat Çiğdem; Piyale, Zeynep Ecem; Ebcim, EfsaneRecent contact literature has shown that imagining a positive intergroup encounter improves intergroup attitudes and behaviors, yet less is known about the effects of imagined contact in high conflict settings. We conducted three studies to understand the potential effects of imagined intergroup contact among ethnic Turks ( majority status) and ethnic Kurds ( minority status) in the Turkish-Kurdish interethnic conflict setting. Study 1 (N = 47, Turkish) tested standard imagined contact effects ( neutral vs. standard imagined contact condition) among majority Turks and showed that imagined contact was effective on outgroup attitudes, perceived threat, intergroup anxiety, and support for multiculturalism only among participants with higher ethnic identification. Study 2 (N = 107, Turkish) examined how ethnic identification of the contact partner would influence the effectiveness of the standard imagined contact scenario ( neutral vs. standard vs. ethnic identification condition) and demonstrated that imagined contact effects were more negative when the contact partner identified with his/her ethnic group during imagined contact. Study 3 (N = 55, Kurdish) investigated imagined contact effects ( neutral vs. standard imagined contact condition) among an ethnic minority group and showed that imagined contact did not improve minority group members' outgroup attitudes, but did decrease intergroup anxiety and perceived discrimination (marginally significantly) and increased perceived positive attitudes from the majority group. Practical implications of the use of imagined intergroup contact strategy in conflict-ridden settings were discussed.Yayın The use of Facebook by Turkish mothers: its reasons and outcomes(Springer, 2020-03-01) Ögel Balaban, Hale; Altan, ŞebnemObjectives: Parents use social network sites for reasons related to bridging and bonding social capital, and entertainment. The aim of the present study was to examine whether the use of Facebook by Turkish mothers and its reasons are related to mothers’ demographic characteristics, anxiety level and perceived social support. It also examined whether mothers’ Facebook use contributes to their perception of their parental role. Methods: Three hundred thirty-two middle-class Turkish mothers who reported to use Facebook completed the demographic information questionnaire, the use of social media questionnaire, the anxiety inventory, the perceived social support scale and the self-perception of parental role questionnaire. Results: Results indicated that Turkish mothers use Facebook more for reasons related to bridging social capital than reasons related to bonding social capital and entertainment. The frequency of using Facebook and the length of time having an account predicted the use of Facebook for reasons related to bridging and bonding social capital. Anxiety level predicted the use of Facebook for reasons related to entertainment. Mothers’ Facebook use was found not to be related to their self-perceived parental competence. Conclusions: The discussion of these findings in terms of Turkish culture implied the need for cross-cultural studies for a better understanding of parents’ use of social network sites.Yayın Cross-group friendships and psychological well-being: A dual pathway through social integration and empowerment(Wiley, 2018-10-01) Bağcı Hemşinlioğlu, Sabahat Çiğdem; Türnüklü, Abbas; Bekmezci, EyüpThis study investigated the associations between cross-group friendships and psychological well-being among a sample of physically disabled adults. A total of 269 disabled people (M-age=39.13, SD=13.80; 114 females, 152 males, 3 unknown) completed questionnaires including the quality of their friendships with non-disabled people, perceived majority group's attitudes towards the minority group, collective self-esteem, collective action tendencies, own outgroup attitudes, and psychological well-being. Findings demonstrated that disabled people's cross-group friendships were directly and indirectly associated with higher levels of psychological well-being via two routes: one by promoting perceived majority attitudes which consequently led to more positive own outgroup attitudes (well-being through social integration hypothesis) and the other by leading to higher levels of collective self-esteem which enhanced collective action tendencies (well-being through empowerment hypothesis). Findings offer important insights into the study of cross-group friendships in relation to the psychological well-being of stigmatized minority group members.
