871 resultados para stated preferences


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Preferences are present in many real life situations but it is often difficult to quantify them giving a precise value. Sometimes preference values may be missing because of privacy reasons or because they are expensive to obtain or to produce. In some other situations the user of an automated system may have a vague idea of whats he wants. In this thesis we considered the general formalism of soft constraints, where preferences play a crucial role and we extended such a framework to handle both incomplete and imprecise preferences. In particular we provided new theoretical frameworks to handle such kinds of preferences. By admitting missing or imprecise preferences, solving a soft constraint problem becomes a different task. In fact, the new goal is to find solutions which are the best ones independently of the precise value the each preference may have. With this in mind we defined two notions of optimality: the possibly optimal solutions and the necessary optimal solutions, which are optimal no matter we assign a precise value to a missing or imprecise preference. We provided several algorithms, bases on both systematic and local search approaches, to find such kind of solutions. Moreover, we also studied the impact of our techniques also in a specific class of problems (the stable marriage problems) where imprecision and incompleteness have a specific meaning and up to now have been tackled with different techniques. In the context of the classical stable marriage problem we developed a fair method to randomly generate stable marriages of a given problem instance. Furthermore, we adapted our techniques to solve stable marriage problems with ties and incomplete lists, which are known to be NP-hard, obtaining good results both in terms of size of the returned marriage and in terms of steps need to find a solution.

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Wie kann man Ergebnisse internationaler Umweltpolitik erklären? Wie hilfreich ist dabei die liberale Theorie der Internationalen Beziehungen (IB) von Andrew Moravcsik? Die vorliegende Arbeit versucht diese Fragen anhand eines Fallbeispiels internationaler Umweltpolitik – der Position der Bundesrepublik Deutschland bezüglich der einzelnen Streitfragen der EU-Verordnung 443/2009 über den CO2-Ausstoß von Automobilen – zu beantworten. Es wird eine theoriegeleitete Außenpolitikanalyse durchgeführt, deren Hauptaugenmerk auf der spezifischen nationalen Präferenzbildung in einem bestimmten Fall liegt. Hier weist Moravcsiks Theorie eine „Lücke“ auf. Wessen Interessen sich aus welchen Gründen in einer bestimmten Situation wie durchsetzen und damit Politik beeinflussen bleibt unklar. Deshalb erweitert die Arbeit Moravcsiks liberale Theorie der IB mithilfe von Annahmen und Erkenntnissen aus der Verbändeforschung nach innen. Auf diese Weise werden die situationsspezifischen Interessen und die situationsspezifische Durchsetzungsfähigkeit der betroffenen Akteure – nationale Interessengruppen – erhoben und untersucht, inwiefern man mit ihrer Hilfe die deutsche Position zur EU-Verordnung 443/2009 erklären kann. Empirisch erweist sich dabei, dass die Position der BRD zu acht von neun Streitfragen der EU-Verordnung 443/2009 den Interessen einer Koalition aus Industriegewerkschaft (IG) Metall und Verband der Automobilindustrie (VDA) entsprach, weil diese im vorliegenden Fall mit Abstand die größte Durchsetzungsfähigkeit aufwiesen. Lediglich bezüglich einer Streitfrage wich die Position der BRD von den Interessen von IG Metall und VDA ab. Damit lässt sich festhalten: Die Position der BRD zur EU-Verordnung 443/2009 kann weitgehend mithilfe der nach innen erweiterten liberalen Theorie nach Andrew Moravcsik erklärt werden. Trotz möglicher Schwierigkeiten bei der Übertragung erscheint daher eine Anwendung des nach innen erweiterten Liberalismus auf weitere erklärungsbedürftige Phänomene der internationalen Umweltpolitik und damit eine Überprüfung der Theorie insgesamt eine interessante und sinnvolle Aufgabe zu sein.

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Pharmacological cognitive enhancement (CE) is a topic of increasing public awareness. In the scientific literature on studentrnuse of CE as a study aid for academic performance enhancement, there are high prevalence rates regarding the use ofrncaffeinated substances (coffee, caffeinated drinks, caffeine tablets) but remarkably lower prevalence rates regarding the usernof illicit/prescription stimulants such as amphetamines or methylphenidate. While the literature considers the reasons andrnmechanisms for these different prevalence rates from a theoretical standpoint, it lacks empirical data to account for healthyrnstudents who use both, caffeine and illicit/prescription stimulants, exclusively for the purpose of CE. Therefore, wernextensively interviewed a sample of 18 healthy university students reporting non-medical use of caffeine as well as illicit/rnprescription stimulants for the purpose of CE in a face-to-face setting about their opinions regarding differences in generalrnand morally-relevant differences between caffeine and stimulant use for CE. 44% of all participants answered that there is arngeneral difference between the use of caffeine and illicit/prescription stimulants for CE, 28% did not differentiate, 28% couldrnnot decide. Furthermore, 39% stated that there is a moral difference, 56% answered that there is no moral difference andrnone participant was not able to comment on moral aspects. Participants came to their judgements by applying threerndimensions: medical, ethical and legal. Weighing the medical, ethical and legal aspects corresponded to the students’rnindividual preferences of substances used for CE. However, their views only partly depicted evidence-based medical aspectsrnand the ethical issues involved. This result shows the need for well-directed and differentiated information to prevent thernpotentially harmful use of illicit or prescription stimulants for CE.

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Rural tourism has been widely promoted in the European Union as an effective measure counteracting economic and social challenges facing rural areas especially those with declining agriculture economies. Particularly its role is seen in provision and maintenance of public goods which are more and more demanded by the public and considered in the policymaking. In Kosovo, rural tourism has been developed through the support of the international organizations and private sector initiatives, with primary aim to generate additional income for rural households and sustainable management of natural and cultural resources. Anyhow, it could be stated that the use of territorial capital to enhance the quality of the tourist offer and undertake promotion at wider circles of people has not been well explored so far, particularly possible links with agriculture that would satisfy visitors demand. In this regard this research study analyzes involvement of local stakeholders and use of territorial capital to develop tourist offer in rural areas of Kosovo. Beside, study applies comparative approach with other two areas of the European Union, Appennino Bolognese in Italy and Alpujara in Spain, to understand and compare the process of rural tourism development and demand characteristics between Kosovo and these areas. A survey has been conducted in all three study areas with rural tourism visitors to understand their preferences for public and private goods and services when visiting rural areas and the role of agriculture in sustaining rural tourism. Results show that there is a potential to link rural tourism with agriculture in Kosovo, which would help in sustaining agriculture and add additional value to local food products, which in return would enhance the tourist offer and make it more attractive for the visitors but also for the farmers as an additional revenue generating sector.

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Rapid speciation in Lake Victoria cichlid fish of the genus Pundamilia may be facilitated by sexual selection: female mate choice exerts sexual selection on male nuptial coloration within species and maintains reproductive isolation between species. However, declining water transparency coincides with increasingly dull coloration and increasing hybridization. In the present study, we investigated the mechanism underlying this pattern in Pundamilia nyererei, a species that interbreeds with a sister species in turbid but not in clear water. We compared measures of intraspecific sexual selection between two populations from locations that differ in water transparency. First, in laboratory mate-choice experiments, conducted in clear water and under broad-spectrum illumination, we found that females originating from turbid water have significantly weaker preferences for male coloration than females originating from clear water. Second, both the hue and body coverage of male coloration differ between populations, which is consistent with adaptation to different photic habitats. These findings suggest that the observed relationship between male coloration and water transparency is not mediated by environmental variation alone. Rather, female mating preferences are indicated to have changed in response to this variation, constituting the first evidence for intraspecific preference-trait co-evolution in cichlid fish. (C) 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 398-406.

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This study examines the links between human perceptions, cognitive biases and neural processing of symmetrical stimuli. While preferences for symmetry have largely been examined in the context of disorders such as obsessive-compulsive disorder and autism spectrum disorders, we examine various these phenomena in non-clinical subjects and suggest that such preferences are distributed throughout the typical population as part of our cognitive and neural architecture. In Experiment 1, 82 young adults reported on the frequency of their obsessive-compulsive spectrum behaviors. Subjects also performed an emotional Stroop or variant of an Implicit Association Task (the OC-CIT) developed to assess cognitive biases for symmetry. Data not only reveal that subjects evidence a cognitive conflict when asked to match images of positive affect with asymmetrical stimuli, and disgust with symmetry, but also that their slowed reaction times when asked to do so were predicted by reports of OC behavior, particularly checking behavior. In Experiment 2, 26 participants were administered an oddball Event-Related Potential task specifically designed to assess sensitivity to symmetry as well as the OC-CIT. These data revealed that reaction times on the OC-CIT were strongly predicted by frontal electrode sites indicating faster processing of an asymmetrical stimulus (unparallel lines) relative to a symmetrical stimulus (parallel lines). The results point to an overall cognitive bias linking disgust with asymmetry and suggest that such cognitive biases are reflected in neural responses to symmetrical/asymmetrical stimuli.

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Using survey methodology, a cross sectional study was undertaken to ascertain whether first and fourth year college women have different perceptions and behavior associated with short term mating preferences. It was hypothesized that after incurring significant negative or costly experiences associated with hooking up, fourth year women would prefer men who had qualities associated with a desired long term partner as opposed to characteristics associated with short term mating partners. The results were partially consistent with the hypothesis. Reported preferences in a desired partner and perspective on hooking up differ between first and fourth year groups. No difference was found between frequency and willingness to hookup between the two groups. The findings are explained in terms of evolutionary theory, social exchange theory, and sexual script concepts.

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To investigate how involvement preferences of patients with breast cancer change during the treatment decision-making process and determine the impact of meeting patients' expectations on decision-making outcomes.

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Using survey methodology, a cross sectional study was undertaken to ascertain whether first and fourth year college women have different perceptions and behavior associated with short term mating preferences. It was hypothesized that after incurring significant negative or costly experiences associated with hooking up, fourth year women would prefer men who had qualities associated with a desired long term partner as opposed to characteristics associated with short term mating partners. The results were partially consistent with the hypothesis. Reported preferences in a desired partner and perspective on hooking up differ between first and fourth year groups. No difference was found between frequency and willingness to hookup between the two groups. The findings are explained in terms of evolutionary theory, social exchange theory, and sexual script concepts.

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Rats learn to prefer flavors that are followed by postingestive effects of nutrients. This experiment investigated whether the timing of a flavor (specifically, in the first or second half of the meal) influences learning about that flavor. Stronger learning about earlier or later flavorswould indicate when the rewarding postingestive effects of nutrients are sensed. Ratswith intragastric (IG) catheters drank saccharin-sweetened, calorically-dilute solutions with distinct flavors added, accompanied by IG infusion of glucose (+sessions) or water (−sessions). In both types of sessions, an “Early” flavorwas provided for the first 8 min and a “Late” flavor for the last 8 min. Thus, rats were trained with Early(+) and Late(+) in high-caloriemeals, and Early(−) and Late(−) in low-calorie meals. Strength of the learned preference for Early(+) and Late(+) was then assessed in a series of two-bottle choice tests between Early(+) vs. Early(−), Late(+) vs. Late(−), Early(+) vs. Late(+), and Early(−) vs. Late(−). Rats preferred both Early(+) and Late(+) over the respective (−) flavors. But Early(+)was only preferredwhen rats were tested hungry. Late(+) was preferred when rats were tested hungry or recently satiated. This indicates qualitatively different associations learned about flavors at different points in themeal.While not supporting the idea that postingestive effects become most strongly associated with later-occurring (“dessert”) flavors, it does suggest a reason dessert flavors may remain attractive in the absence of hunger.

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The objective of this study was to explore the perception of the legal authorities regarding different report types and visualization techniques for post-mortem radiological findings.

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Present package information leaflets do not fulfil the needs of many patients. The objective of this study was to investigate patients' preferences towards content and presentation of drug information leaflets using prepared medication brochures in a discrete choice experiment.