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Many optimisation problems arise in managing the Blood Donation (BD) supply chain. Most of them have been addressed in the literature, while other problems, e.g. donation scheduling, have not been sufficiently addressed so far. However, blood collection from donors may have a disruptive impact on the entire BD supply chain if not properly managed. For example, scheduling donation appointments based on some system metrics may improve the flow of blood units through the BD supply chain and increase the quality of service perceived by donors. In this short communication, we present the donation scheduling problem and highlight the lack of work in the literature that deals with this problem. Then, we analyse the impact of an unbalanced flow of blood units on the BD system and the benefits that may derive from a suitable appointment scheduling. Finally, we propose suggestions for future research in BD collection scheduling that may improve the BD process. 相似文献
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Demographic ageing is a challenge for many countries. Even though Turkey has a relatively younger demographic composition, the proportion of the older people (65+) within the population is rapidly increasing. Within this framework, older people are becoming more important clients for both social work students and social workers in Turkey. This study aims to reveal the attitudes of social work students towards older people and determine the various factors that affect their views on older persons. In the scope of the project, Kogan's Attitude Towards Old People Scale was applied to 419 social work undergraduate students at a university located in Central Anatolia. The findings showed that social work students scored a mean of 130.96 and they generally had positive attitudes towards older people. The correlation between year of study, gender and age was not statistically significant. However, having lived mostly in urban areas was positively correlated with the mean Kogan scores and this finding was found to be statistically significant. Exposure to personal contact with older people at both the personal and professional levels was influential in shaping attitudes about the older people. 相似文献
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Merve Kandemir Çetinkaya Selahattin Kaçıranlar 《Journal of Statistical Computation and Simulation》2019,89(14):2645-2660
Negative binomial regression (NBR) and Poisson regression (PR) applications have become very popular in the analysis of count data in recent years. However, if there is a high degree of relationship between the independent variables, the problem of multicollinearity arises in these models. We introduce new two-parameter estimators (TPEs) for the NBR and the PR models by unifying the two-parameter estimator (TPE) of Özkale and Kaç?ranlar [The restricted and unrestricted two-parameter estimators. Commun Stat Theory Methods. 2007;36:2707–2725]. These new estimators are general estimators which include maximum likelihood (ML) estimator, ridge estimator (RE), Liu estimator (LE) and contraction estimator (CE) as special cases. Furthermore, biasing parameters of these estimators are given and a Monte Carlo simulation is done to evaluate the performance of these estimators using mean square error (MSE) criterion. The benefits of the new TPEs are also illustrated in an empirical application. The results show that the new proposed TPEs for the NBR and the PR models are better than the ML estimator, the RE and the LE. 相似文献
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This paper aims to contribute to the existing studies on the young women’s transition to adulthood in the case of Turkish women’s exclusion from the labour market. The issue is discussed largely within the boundaries of traditional gender restrictions that keep women out of employment. Herein, we argue that the gender-based control of young women, perceived as the reason for their exclusion from the labour market, may be used by disadvantaged women as a way of avoiding difficult and unfavourable employment situations. Similarly, the gender roles imposed on men could also not be fulfilled due to the same restrictive labour market conditions. Furthermore, we suggest that the poverty simultaneously strengthens and erodes the very base of the traditional gender structure for both young women and young men, while forcing the young women out of employment and the young men to the unstable working conditions. This argument is based on a study conducted in Alt?nda?, Ankara with a sample of 279 females and 340 males aged between 15 and 24. A mixed methodology, comprising a survey questionnaire followed by 60 in-depth interviews and 4 focus group discussions, was employed for this study. 相似文献
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Contemporary managers are developing alternative ways to sustain their competitive advantages. Motivation-enhancing features such as high-quality meal service provided by organizations can be thought of as one of these methods. The effect of the perceived quality of meal service provided by organizations on the job performance of employees and the mediating role of organizational identification during this process is studied. Private security-sector employees working in Turkey (N?=?597) are being focused in this study. As a result of analyses (correlation and regression analyses, structural equation model), the authors find that the perceived quality of meal service provided by organizations improves employees’ job performance significantly and organizational identification has a partial mediating role on this association. The findings of this study will be of interest to key stakeholders such as public or private organizations, labor unions and the media. 相似文献
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Gül Çalışkan 《International Review of Sociology》2014,24(3):450-470
This paper examines the discursive messages conveyed through everyday encounters among German-born Turkish Ausländer (foreigners) and ethnic Germans in Berlin. Using narrative analysis, I explore how these messages operate to maintain a series of separate and unequal social relations based on gender, ethnicity, religion, and skin colour. The personal experiences of local residents illustrate how these discourses serve to mark some Ausländer as less threatening than others, some as preferable, and others as undesirable. Some Ausländer are also considered more valuable than others, and the status of one often depends on the superior or subordinate status of the other. Through exploring these complexities as experienced by local informants, this paper shows the importance of certain interactive processes that construct Ausländerness in varying ways, while still defining people's identities in relation to norms that privilege the dominant subjects. 相似文献
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Aycan Çelikaksoy Helena Skyt Nielsen Mette Verner 《Review of Economics of the Household》2006,4(3):253-275
It is a stylized fact that marriage formation involves positive assortative matching on education. We also find this in the
case of immigrants, even when they tend to “import” their spouses and potentially trade off education for other favorable
characteristics. For Pakistanis, we find positive compensating differentials in terms of high education to youth having adopted
host country norms, when marrying a marriage migrant. This indicates that Pakistani marriage migrants pay a premium to be
able to marry and live in Denmark. For Turks, individuals having source country norms pay a premium in order to import a partner,
indicating that unspoiled traditional norms are traded off for education.
相似文献
Mette Verner (Corresponding author)Email: |
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The mixture distribution models are more useful than pure distributions in modeling of heterogeneous data sets. The aim of this paper is to propose mixture of Weibull–Poisson (WP) distributions to model heterogeneous data sets for the first time. So, a powerful alternative mixture distribution is created for modeling of the heterogeneous data sets. In the study, many features of the proposed mixture of WP distributions are examined. Also, the expectation maximization (EM) algorithm is used to determine the maximum-likelihood estimates of the parameters, and the simulation study is conducted for evaluating the performance of the proposed EM scheme. Applications for two real heterogeneous data sets are given to show the flexibility and potentiality of the new mixture distribution. 相似文献
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AK Thompson 《Social movement studies》2020,19(5-6):537-555
ABSTRACT Although rarely considered within the existing scholarship on social movements, even a cursory analysis of protest activity suggests that movements regularly invoke historical citations (whether consciously or not) while working to clarify aims and mobilize constituencies. In order to make sense of this process, and to account for the variations that arise among the different citation modalities favored by movements on opposite ends of the political spectrum, I draw upon the theoretical contributions of Marxist cultural critic Walter Benjamin and, in particular, on his exploration of ‘wish images’ and ‘dialectical images,’ their attributes, and their interrelationship. According to Benjamin, such images summoned the past either to project visions of future happiness (as with the wish image) or to deposit the witness before a moment of decisive, present-tense reckoning. After outlining the role of historical citation in social movements and in the broader cultural field through which these movements find expression, I analyze two recent protest events – the ‘Unite the Right’ rally in Charlottesville, VA, in which wish images were actively deployed, and the 2017 Women’s Strike in New York City, where a dialectical image arose from the constellated nodes of the march’s route – to consider the relationship between citation modality and protest outcome. Following from this analysis, and in keeping with the unapologetically partisan nature of my investigation, I conclude by advancing some strategic recommendations for movements seeking – as Benjamin once enjoined – to ‘improve our position in the struggle against Fascism.’ 相似文献