• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 51
  • 13
  • 10
  • 9
  • 6
  • 6
  • 4
  • 3
  • 1
  • 1
  • 1
  • Tagged with
  • 124
  • 18
  • 13
  • 12
  • 12
  • 11
  • 11
  • 10
  • 9
  • 9
  • 9
  • 8
  • 8
  • 8
  • 7
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Purificação de anticorpos monoclonais utilizando IMAC em membranas de fibra oca de PEVA : c : omparação dos agentes quelantes IDA, CM-Asp e TREN / Purification on monoclonal antibodies using IMAC in PEVA hollow fiber membranes: comparison of chelating agents IDA, CM-Asp and TREN

Bresolin, Igor Tadeu Lazzarotto 07 November 2006 (has links)
Orientador: Sonia Maria Alves Bueno / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-06T20:08:56Z (GMT). No. of bitstreams: 1 Bresolin_IgorTadeuLazzarotto_M.pdf: 4686617 bytes, checksum: ed7a688421b5d854024279523878c12a (MD5) Previous issue date: 2006 / Resumo: Anticorpos monoclonais são imunoglobulinas secretadas por clones de linfócitos B, normais, tumorais ou obtidos pela tecnologia de hibridomas. Os anticorpos monoclonais têm sido utilizados nas áreas analítica e terapêutica, o que implica na necessidade de sua obtenção com pureza superior a 95%. Muitos estudos têm sido realizados visando à purificação de anticorpos monoclonais, destacando-se as técnicas de adsorção seletiva, como as cromatografias de troca iônica, hidrofóbica e de afinidade. Neste trabalho aplicou-se a cromatografia de afinidade em membranas de álcool polietileno-vinílico (PEVA), comparando o desempenho dos agentes quelantes (AQ) ácido iminodiacético (IDA), ácido aspártico carboximetilado (CM-Asp) e tris-2(aminoetil)amina (TREN) com íons metálicos imobilizados na purificação de anticorpos monoclonais anti-TNP, isotipo IgG1 a partir de sobrenadante de cultura celular precipitado e dialisado. Para determinar as melhores condições de adsorção e eluição na presença de diferentes sistemas tamponantes, foram testados os quelatos AQ-Ni2+, AQ-Zn2+ e AQ-Co2+, bem como os agentes quelantes sem metal imobilizado como grupos ionogênicos. De acordo com eletroforeses SDS-PAGE e análises ELlSA das frações dos picos de proteína obtidos, as melhores condições utilizadas para a purificação foi o uso de membranas PEVA-IDA-sem metal e PEVA-CM-Asp-Zn2+, em presença de tampão Tris-HCI 50 mM a pH 7,0 e eluição por aumento de concentração de Tris, atingindo fatores de purificação de 138,9 e 103,8 e pureza de 92,3% e 68,1%, respectivamente. A partir das isotermas de adsorção, determinou-se a capacidade máxima de adsorção e a constante de dissociação dos complexos IDA-lgG1 e CM-Asp-Zn2+ -lgG1 que, de acordo com o ajuste dos parâmetros pelo modelo de Langmuir, mostraram alta capacidade de adsorção e constantes de dissociação características de sistemas de afinidade média. Com o módulo de fibras ocas, construído em nosso laboratório, determinaram-se as curvas de ruptura por meio de experimentos de filtração para os processos propostos, e os resultados obtidos demonstraram que os sistemas de fibras ocas PEVA-IDA e PEVA-GM-Asp-Zn2+ são factíveis para a purificação de anticorpos monoclonais do isotipo IgG1 / Abstract: Monoclonal antibodies are immunoglobulins produced by normal, tumoral or hybrids Iymphocytes 8 obtained by hibridoma technology. Hybridomas are resulted from the fusion of Iymphocytes B with malignant myeloma cells which express both the Iymphocyte's property of specific-antibody production and the immortal characteristic of the myeloma cells. Monoclonal antibodies have been used in analytic and therapeutic areas. This application needs highly pure antibodies. Many techniques have been studied focusing monoclonal antibodies purification. These techniques include ion exchange, hydrophobic and affinity chromatography. In this study, we applied polyethylenevinyl alcohol (PEVA) membranes in the purification of monoclonal antibody from cel! culture supematant comparing the chelating agents Iminodiacetic Acid (IDA), Carboxy-methyl Aspartic Acid (CM-Asp) and Tris-2(aminoethyl)amine) (TREN) with different immobilized metal ios, Ni2+, Zn2+ and C02+, and with different buffers. We also evaluated the adsorption and purification of monoclonal antibodies using the chelating agents as ionogenic groups. According to SDS-PAGE electrophoresis and ELlSA analysis, the higher selectivity was obtained in the presence of 50 mM Tris-HCI buffer, pH 7,0 and with elution by increasing Tris concentration, with CM-Asp-Zn2+ and IDA as ionogenic group, which provided the purification of IgG with traces of albumin, reaching purification factors of 138.9 and 103.8 and purities of 92.3% and 68.1, respectively. The adsorbent capacity and the dissociation constant of the complexes IDA-lgG1 e CM-Asp-Zn2+ -lgG1 were determinate from adsorption isotherms. According to Langmuir model, the results indicated that the matrix presents high adsorption capacity and a dissociation constant characteristic for intermediate affinity systems. We also evaluated the breaktrough curves for the proposed processes. These breaktrough curves are important to scale up procedure / Mestrado / Desenvolvimento de Processos Biotecnologicos / Mestre em Engenharia Química
82

Continuous Auditing : Internal Audit at a Crossroads?

Andersson Skantze, Joel January 2017 (has links)
Purpose – It is argued that traditional audit methods are becoming outdated in terms of delivering sufficient assurance on business objectives, whereby, a paradigm shift towards continuous auditing (CA) is proposed and perceived as necessary both by academia, standard-setting groups, and business society. However, the practical prevalence of CA is insignificant in relation to the expectations depicted. Therefore, the purpose of this paper is to examine why this is the case by means of investigating what factors that motivate an adoption of CA amongst various internal audit functions (IAFs). Design/methodology/approach – The study draws on the Technology Acceptance Model (TAM), and data are obtained through semi-structured interviews capturing internal auditors’ attitude towards CA, and what factors that influence an adoption. Findings – There is a shattered view on CA amongst IAFs, where the proponents embrace it as a set of value-adding methodologies whilst the opponents argue that it falls outside their responsibility and threaten the independence of the function. Thus, why CA has not been leveraged to its full potential is, in contrast to previous research, not solely attributable to practical factors but also due to the IAFs’ vast differences in approach to CA as a concept. Practical implications – The study has brought attention to the distinguished disparity found in internal auditors’ attitude towards CA. Ultimately, doubts, whether CA should be leveraged by IAFs has come to light. These are hurdles that need to be considered, both by academia, standard-setting groups, and business society if the leap for CA ought to continue. Originality/value – The use of semi-structured interviews contributes to in-depth understandings and insights of the internal auditors’ attitudes towards CA. Moreover, such an approach is more likely to capture the stance towards CA in greater detail than that possible of previous large-scale surveys.
83

Novel Characteristic-Mode-Based Synthesis and Analysis Method for Reflectarray Antennas

Maalik, Abdul 13 November 2020 (has links)
No description available.
84

Demonstrační úlohy s KNX/EIB / Demonstration examples with KNX/EIB

Křivka, Martin January 2012 (has links)
This diploma thesis was created as a support for Building automation course, at the Institute of Automation and Computer Science of the Faculty of Mechanical Engineering at Brno University of Technology. The aim of this diploma thesis is to get acquainted with elements of intelligent electrical ABB i-bus® KNX/EIB and create tasks suitable for laboratory teaching. Subsequently, use the communication module DataLab IF/EIB to connect KNX/EIB with Control Web system and create in this environment visualization of the status of these devices. Furthermore, using the communication module CM EIB/KNX to connect KNX/EIB with the programmable controller LOGO! and create additional laboratory task.
85

Mechanism of mesenchymal stromal cells secretome-mediated trabecular meshwork regeneration for glaucoma therapy

Tebid, Christian Tebid 10 1900 (has links)
In open angle glaucoma, dysfunction of the trabecular meshwork (TM) results in impaired aqueous humour outflow leading to an elevated intraocular pressure (IOP) that underlies optic nerve damage and irreversible blindness. Currently, no curative treatment is available for the disease. Indeed, most pharmacological and surgical interventions usually provide only temporary relief from elevated IOP while little progress has been made in targeting the root cause of this disease: correcting the dysfunctional TM. In this context, we hypothesized that regeneration/refunctionalization of the TM may represent an effective therapeutic option to halt disease progression or even reverse the pathologic process. We previously demonstrated in a rat model of glaucoma that the injection of mesenchymal stromal cells (MSCs) cultured under hypoxic conditions or their conditioned media (MSC-CM) into laser-damaged TM area results in tissue regeneration. Injection of MSC or conditioned media in our glaucoma model led to activation and proliferation of ocular progenitor cells culminating in TM regeneration and a decrease in IOP. However, the mechanistic basis for this regenerative process remained elusive. Thus, the aim of this thesis is to elucidate the mechanistic basis of MSC secretome-mediated TM regeneration and the subsequent decrease in IOP. We now demonstrate that injection of hypoxic MSC-CM into laser-induced glaucomatous eyes resulted in massive immune cell recruitment. We also demonstrate that these hypoxic MSC-CM conditioned cells produced pro-regenerative factors in vitro and in vivo. Next, employing a proteomic approach, we identified and verified the pro-regenerative effect of several factors secreted by hypoxic MSC-CM recruited cells, which in turn induced the activation/proliferation of ocular progenitor cells leading to TM regeneration and decreased IOP. Upon individual injection of the purified factors into glaucomatous rat eyes, we observed a partial and delayed but significant decrease in IOP that correlated with an increase in the activation and proliferation of neuronal progenitor cells in the TM area. The co-injection of these factors resulted in a significant decrease in IOP compared with individual factor injection. Importantly, this drop in IOP was associated with restoration of retinal functionality, thus demonstrating the importance of these factors in the TM regeneration process and disease control. The findings presented in this thesis provide a novel acellular therapeutic approach for glaucoma treatment via in situ TM regeneration. Moreover, the knowledge gained here could have a lasting impact on how we induce tissue regeneration in other degenerative diseases and lead to novel therapeutic advances in regenerative medicine. / Dans le glaucome à angle ouvert, le dysfonctionnement du trabéculum (TM), un tissu nécessaire à la filtration de l'humeur aqueuse, entraîne une élévation de la pression intraoculaire (PIO). Ceci cause des lésions au niveau du nerf optique et une cécité irréversible. Présentement, aucun traitement curatif n'a été développé pour cette maladie. Nous émettons l'hypothèse que la régénération et re-fonctionnalisation du trabéculum peut représenter une option thérapeutique efficace pour arrêter ou inverser la progression de la maladie dans de nombreux cas de glaucome. Nous avons précédemment démontré les effets régénérateurs des cellules mésenchymateuses (MSCs) et de leurs milieux conditionnés par l'hypoxie (MSC-CM) dans la régénération du TM suite à un dommage par laser. Ce processus a conduit à l'activation et à la prolifération des cellules progénitrices oculaires résultant en une diminution de la PIO dans un modèle de glaucome induit par laser chez le rat. Cependant, la base mécanistique de ce processus de régénération reste encore inconnue. Ainsi, le but de cette thèse de recherche est d'élucider cette base mécanistique de la régénération du TM médiée par le sécrétome des MSC et la diminution subséquente de la PIO. À cette fin, l'injection de MSC-CM hypoxique dans les yeux glaucomateux induits par laser a entraîné un important recrutement de cellules immunitaires. Sous l’action du MSC-CM, ces cellules produisent des facteurs pro-régénératifs in vitro et in vivo. Ensuite, nous avons utilisé une approche protéomique et vérifié l'effet pro-régénératif des facteurs sécrétés par ces cellules exposées au MSC-CM hypoxique, sur l'activation et la prolifération des cellules progénitrices oculaires et la PIO. Lors de l'injection de ces facteurs chez le rat glaucomateux, nous avons observé une augmentation significative de l'activation et de la prolifération des cellules progénitrices neuronales présentes dans la zone du TM, résultant en une diminution de la PIO. De plus, l’injection combinée de ces facteurs résulte en une diminution synergique importante de la PIO. Cette baisse de la PIO était associée à une restauration de la fonction rétinienne, démontrant ainsi l'importance de ces facteurs dans le processus de régénération du TM et de contrôle de la maladie. Les résultats présentés dans cette thèse pourraient amener à une nouvelle approche thérapeutique acellulaire pour le traitement du glaucome via la régénération du TM. De plus, les connaissances acquises au cours de cette thèse pourraient avoir un impact durable sur la manière d’aborder la régénération tissulaire dans d'autres maladies dégénératives et amener des avancées thérapeutiques nouvelles en médecine régénératrice
86

Modular Approach for Characterizing and Modeling Conducted EMI Emissions in Power Converters

Liu, Qian 22 November 2005 (has links)
With the development of power electronics, electromagnetic interference (EMI) and electromagnetic compatibility (EMC) issues have become more and more important for both power converter designers and customers. This dissertation studies EMI noise emission characterization and modeling in power converters. A modular-terminal-behavioral (MTB) equivalent EMI noise source modeling approach is proposed. This work is the first to systematically develop a 3-terminal EMI noise source model for a switching phase-leg device module. Each module is modeled as pairs of equivalent noise current sources and source impedances. Although the proposed MTB modeling approach applies the linear circuit theory to a semiconductor switching device, which exhibits nonlinear behavior during switching transients, the analysis and experiments show that the nonlinearity has negligible practical effect on the modeling methodology. The validation range of the modeling methodology has been analyzed. One of the differences between the proposed MTB model and the other state-of-the-art models is that the MTB model characterizes and predicts the CM and DM noise simultaneously. The inseparable high-frequency CM and DM noise characteristics contributed by the source impedance and propagation path are analyzed. A comprehensive evaluation of different EMI noise source modeling approaches according to the criteria of accuracy, feasibility and generality has been presented. Results show that the MTB modeling approach is more accurate, feasible and general than other approaches. The modular and terminal characteristics of the MTB noise source model are verified in two more complicated cases. One example is the application of the MTB equivalent source model in a half-bridge AC converter with variable switching conditions. Although the MTB model is derived under a certain operating condition, the models under different conditions can be combined together to predict the EMI noise for the converter with variable switching conditions. Another example is the application of the MTB equivalent source model in multi-phase-leg converters. The EMI noise of a full-bridge converter is predicted based on the MTB equivalent source model of one phase-leg module. The implementation procedures and results for both applications are verified by the experiment. The applicability of the MTB model in different type of converters is discussed. Based on the MTB model, EMI noise management is explored. The parametric study based on the MTB model is demonstrated by selecting DC-link decoupling capacitors for voltage source converter (VSC). The EMI effect of a decoupling capacitor for a device s safe operation is analyzed, and this analysis shows the terminal characteristics of the MTB model. Both the EMI and voltage overshoot are predicted by the MTB model. A completed converter-level EMI model can be derived based on the noise source model and propagation path model. This model makes it possible to optimize the EMI filter design and study the EMI noise interactions between converters in a power conversion system. / Ph. D.
87

Modeling and Characterization of Power Electronic Converters with an Integrated Transmission-Line Filter

Baisden, Andrew Carson 24 July 2006 (has links)
In this work, a modeling approach is delineated and described in detail; predominantly done in the time domain from low frequency, DC, to high frequencies, 100 MHz. Commercially available computer aided design tools will be used to determine the propagation path in a given structure. Next, an integrated transmission-line filter — fabricated using planar processing technologies — is modeled to accurately predict the EMI characteristics of the system. A method was derived to model the filter's performance in the time-domain while accurately depicting the highly frequency dependant transmission-line properties. A system model of a power factor correction (PFC) boost converter was completed by using active device models for diodes, MOSFETs, and the gate driver. In addition, equivalent circuits were used to characterize high frequency impedances of the passive components. A PFC boost converter was built and used to validate the model. The PFC operated at a peak output power of 1 kW, switching at 400 kHz, with a universal input ranging from 90-270 VRMS with unity power factor. The time-domain and EMI frequency spectrum waveforms are experimentally measured and agree very well with the simulated values; within 5 dB for EMI. The transmission-line filter was also manufactured for model verification, and it is tested for the first time with an operating converter: a PFC at 50 W output and 50 VDC input. The small signal characteristics match the model very well. In addition, impedance interactions between the filter, the converter, and the EMI measurement set-up are discussed, evaluated, measured, and improved to minimize undesired resonances and increase low-frequency EMI attenuation. Experimentally measured attenuation provided by the filter in the range from 100 kHz to 100 MHz was 20-50 dBμV. The simulation also shows a similar attenuation, with the exception of one key resonance not seen in the simulation. / Master of Science
88

Speededness in Achievement Testing: Relevance, Consequences, and Control

Becker, Benjamin 05 December 2023 (has links)
Da Prüfungen und Tests häufig dazu dienen, den Zugang zu Bildungsprogrammen zu steuern und die Grundlage zur Abschlussvergabe am Ende von Bildungsprogrammen bilden, ist ihre Fairness und Validität von größter Bedeutung. Ein kontrovers diskutierter Aspekt standardisierter Tests ist die Verwendung von Zeitlimits. Unabhängig davon ob eine Testadministration Zeitdruck hervorrufen soll oder nicht, sollten Testentwickler:innen in die Lage versetzt werden, den Zeitdruck einer Testadministrationen explizit gestalten zu können. Zu diesem Zweck schlägt van der Linden (2011a, 2011b) einen Ansatz zur Kontrolle des Zeitdrucks von Tests in der automatisierten Testhefterstellung (ATA) unter Verwendung von Mixed Integer Linear Programming und eines lognormalen Antwortzeitmodells vor. Dabei hat der Ansatz von van der Linden jedoch eine zentrale Limitation: Er ist auf das zwei-parametrische lognormale Antwortzeitmodell beschränkt, das gleiche Geschwindigkeits-Sensitivitäten (d.h. Faktorladungen) für alle Items annimmt. Diese Arbeit zeigt, dass ansonsten parallele Testhefte mit unterschiedlichen Geschwindigkeits-Sensitivitäten für bestimmte Testteilnehmende unfair sind. Darüber hinaus wird eine Erweiterung des van der Linden-Ansatzes vorgestellt, die unterschiedliche Geschwindigkeits-Sensitivitäten von Items in ATA berücksichtigt. Weiter wird diskutiert, wie Testhefte mit identischen, aber unterschiedlich angeordneten Items zu Fairness-Problemen aufgrund von Item-Positionseffekten führen können und wie dies verhindert werden kann. Die vorliegende Arbeit enthält zusätzlich Anleitungen zur Verwendung des R-Pakets eatATA für ATA und zur Verwendung von Stan und rstan für Bayesianische hierarchische Antwortzeitmodellierung. Abschließend werden Alternativen, praktische Implikationen und Grenzen der vorgeschlagenen Ansätze diskutiert und Vorschläge für zukünftige Forschungsthemen gemacht. / As examinations and assessments are often used to control access to educational programs and to assess successful participation in an educational program, their fairness and validity is of great importance. A controversially discussed aspect of standardized tests is setting time limits on tests and how this practice can result in test speededness. Regardless of whether a test should be speeded or not, being able to deliberately control the speededness of tests is desirable. For this purpose, van der Linden (2011a, 2011b) proposed an approach to control the speededness of tests in automated test assembly (ATA) using mixed integer linear programming and a lognormal response time model. However, the approach by van der Linden (2011a, 2011b) has an important limitation, in that it is restricted to the two-parameter lognormal response time model which assumes equal speed sensitivities (i.e., factor loadings) across items. This thesis demonstrates that otherwise parallel test forms with differential speed sensitivities are indeed unfair for specific test-takers. Furthermore, an extension of the van der Linden approach is introduced, which incorporates speed sensitivities in ATA. Additionally, test speededness can undermine the fairness of a test if identical but differently ordered test forms are used. To prevent that the score of test-takers depends on whether easy or difficult items are located at the end of a test form, it is proposed that the same, most time intensive items should be placed at the end of all test forms. The thesis also provides introductions and tutorials on using the R package eatATA for ATA and using Stan and rstan for Bayesian hierarchical response time modeling. Finally, the thesis discusses alternatives, practical implications, and limitations of the proposed approaches and provides an outlook on future related research topics.
89

Biomedical Madness / A History of Schizophrenia Research and Biological Psychiatry in Postwar Britain, 1970-1994

Freeborn, Alfred 22 January 2025 (has links)
In den 1980er Jahren erlangte ein biomedizinisches Modell der Schizophrenie, das von Forschern des Clinical Research Centre im Nordwesten Londons entwickelt wurde, internationale Bedeutung auf dem Gebiet der biologischen Psychiatrie. Es konnte jedoch nicht validiert werden, und die am häufigsten wiederholten Beweise, die zu seiner Stützung herangezogen wurden, erwiesen sich als diagnostisch unbedeutend. Trotz der überwältigenden Popularität pharmazeutischer Behandlungen und biologischer Theorien in der heutigen Psychiatrie ist die Geschichte der biologischen Psychiatrie der Nachkriegszeit voll von Enttäuschungen und unerfüllten Erwartungen. Um die Bedeutung von Fortschritt und Scheitern in der biologischen Psychiatrie der Nachkriegszeit zu beurteilen, bietet das biomedizinische Modell der Schizophrenie des CRC eine nützliche Fallstudie. Indem die Entstehung einer biomedizinischen Tatsache nachgezeichnet und dieses biomedizinische Modell in seinen historisch-epistemologischen Kontext gestellt wird, ergibt sich ein subtileres und komplexeres Bild davon, wie biomedizinisches Wissen produziert wird. Es wird argumentiert, dass die Umwandlung der Schizophrenie von einer funktionellen Psychose zu einer rein biologischen Störung in der Nachkriegszeit sinnbildlich für eine umfassendere Verschiebung der erkenntnistheoretischen Schwelle der Psychiatrie ist. / In the 1980s a biomedical model of schizophrenia developed by researchers at the Clinical Research Centre in north-west London gained international ascendancy in the field of biological psychiatry. It failed, however, to be validated and the most replicated piece of evidence used in its support proved to have no diagnostic significance. Despite the overwhelming popularity of pharmaceutical treatments and biological theories in contemporary psychiatry, the history of postwar biological psychiatry is replete with disappointment and unfulfilled expectations. In order to assess the meaning of progress and failure in postwar biological psychiatry, the CRC biomedical model of schizophrenia offers a useful case study. By tracing the genesis of a biomedical fact and placing this biomedical model in its historical-epistemological context, a more subtle and complex picture of how biomedical knowledge is produced is presented. It is argued that the postwar transformation of schizophrenia from a functional psychosis to a purely biological disorder is emblematic of a wider shift in the epistemological threshold of psychiatry.
90

Risks, rewards and rationality / How knowing that you probably won't hit the jackpot affects your judgments and decisions

Leuker, Christina 30 November 2018 (has links)
“Wer nicht wagt, der nicht gewinnt!” —hohe Gewinne sind oft unwahrscheinlich. Theorien der “Adaptiven Kognition” sagen voraus, dass ein solcher statistischer Zusammenhang aus der Welt kognitive Prozesse systematisch beeinflussen kann (u.A. Anderson, 1991; Brunswik, 1944; Gibson, 1979). Im 1. Kapitel gebe ich einen breit gefächerten Überblick warum dies der Fall sein kann. Im 2. Kapitel zeige ich experimentell, dass eine Korrelation zwischen Gewinnhöhe und Gewinnwahrscheinlichkeit Entscheidungen unter Unsicherheit (keine Gewinnwahrschenlichkeit gegeben) beeinflusst. Versuchspersonen schätzten die Gewinnwahrscheinlichkeit gemäß der Gewinnhöhe ein. Im 3. Kapitel zeige ich experimentell, dass Versuchspersonen durch die Korrelation zwischen Gewinnhöhe und Gewinnwahrscheinlichkeit Erwartungen aufbauten: War eine Option “überraschend”, z.B. da sie einen hohen Gewinn mit einer hohen Wahrscheinlichkeit verspricht, wurde eine solch überraschend gute Optionen länger evaluiert. Im 4. Kapitel beschäftige ich mich mit Entscheidungen unter Risiko. Mithilfe eines kognitiven Modells zeige ich, dass eine Struktur, in der hohe Gewinne sich als unwahrscheinlich erweisen, zu einer schnelleren, einfacheren Entscheidungsstrategie führen, als eine unkorrelierte Struktur. Im 5. Kapitel zeige ich, wie das von vielen Menschen angenommene “No free Lunch” Prinzip sich auf die Beurteilung von Risiken im Bereich klinischer Studien auswirkt: Hohe Vergütungen für klinische Studien können dazu führen, dass die Studie als riskanter und schlussendlich unethischer wahrgenommen wird. Zusammengefasst ergänzt die Arbeit ergänzt vorherige Forschung, indem sie zeigt, dass Gewinne und Wahrscheinlichkeiten nicht nur in der Welt systematisch miteinander verbunden sind, sondern auch in der menschlichen Kognition. Dies wirft ein neues Licht auf eine alte Frage: Wer entscheidet wann “rational”, und warum? / The large rewards that people desire are typically unlikely. Theories of adaptive cognition predict that such a regularity can systematically affect how the mind operates (e.g. Anderson, 1991; Brunswik, 1944; Gibson, 1979). In this dissertation, I theoretically and empirically examined how the link between risks and rewards affects judgments and decisions. In Chapter 1, I provide a broad theoretical overview. In Chapter 2, I show how people exploit risk–reward structures in decisions under uncertainty; that is, decisions in which probabilities are unavailable to the decision maker or difficult to ascertain. In these situations, people can infer the probabilities of events directly from the payoffs when risks and rewards are found to be correlated. Chapter 3 shows that risk–reward shapes how people evaluate options in decisions under risk. Surprising options that did not fit surrounding risk–reward structures were linked to longer response times and an increase in pupil size, particularly when options were “surprisingly good”—i.e., when they offered a high payoff and a high probability. Chapter 4 addresses how risk–reward structures affect decisions under risk in general. A computational model showed that risk–reward structures do not change (subjective) preferences in choices. Instead, risk–reward structures affect how people accumulate evidence in risky choice. Specifically, inversely related risks and rewards promote satisficing whereas uncorrelated risks and rewards promote maximizing. In Chapter 5, I provide an example of how risk–reward structures affect decision making in the wild. Specifically, I show that some individuals use very high pay as a cue to infer the potential risks a clinical trial poses. Taken together, this work suggests that people’s risk–reward priors should not be blindly assumed away, and challenges assumptions on who is considered rational and why.

Page generated in 0.2198 seconds