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The Wnts, a family of secreted glycoprotein ligands, act through the frizzled (Fz) receptor, a family of seven-transmembrane (7TM) receptor proteins, to mediate intracellular signaling pathways that regulate cell fate determination, cell migration, or both. Whereas many molecular components of the Wnt signal transduction cascade have been identified, it remains unclear how the signal is transduced from the Fz receptors to the cytoplasm. To address this important question, a membrane-based yeast two-hybrid (MbY2H) screen was performed to identify potential Fz-interacting proteins. For this screen, the Frizzled7 (Fz7) protein was used as the bait and a mouse brain library was used the prey. This screen identified resistance to inhibitors of cholinesterase 8 homolog A (Ric8A), a 542–amino acid cytoplasmic protein, along with other proteins as putative Fz7-binding proteins. Ric8A had been studied previously in C. elegans and D. melanogaster for its function in regulating asymmetric cell division as a receptor-independent guanine nucleotide exchange factor (GEF) for Gα proteins. Additional studies in M. musculus and X. laevis further uncovered a role for this protein during gastrulation and neurulation; however, the mechanisms by which Ric8A regulated these processes remained unclear. In this thesis, I show Ric8A to be a bona fide binding partner for both Fz7; that Ric8A can also bind to the phosphoprotein Dishevelled (Dvl); and that both its interaction with Fz7 and Dvl is Wnt-regulated. The spatial and temporal mRNA expression pattern of the Xenopus homologue of Ric8A suggests a potential role in regulating Wnt signaling. The Xenopus homologue of Ric8A was cloned and gain-of-function and loss-of-function approaches in Xenopus uncovered a role for Ric8A in gastrulation and neural tube closure. Additionally, we found inhibition of Ric8A function mechanistically prevents activation of Rac1 which is required downstream of Wnt/Fz signaling during gastrulation. Overall, this study uncovers a novel regulator of Wnt signaling during early development / Biology

With the spread of synchronous and asynchronous online teaching tools, it has become necessary to identify factors and challenges influencing faculty member adoption of online teaching into teaching practice at Saudi universities. The parallel convergent mixed method was used as the methodology for this study and was conducted in three Saudi universities; Imam Abdulrahman bin Faisal University, King Faisal University, and University of Bisha. The total number of responses from the study instrument was about 124; Imam Abdulrahman bin Faisal University 49, King Faisal University 41, and the University of Bisha 34. The theoretical framework for this study was the Decomposed Theory of Planned Behavior (DTPB) modal. The collection of quantitative and qualitative data as convergent parallel mixed methods was in one phase and concurrently included close-ended and open-ended questions. The data were separately analyzed quantitative and qualitative. The questionnaire instrument was constructed in four parts: (1) faculty demographic information, (2) technologies faculty use most with online teaching, (3) the use of online teaching and learning tools, and (4) utilization of online tools. The first and second sections of the survey instrument were focused on faculty demographics such as gender, age, academic rank, teaching experiences, department or college, nationality, type of contract, and years of experience teaching online courses. Additional information about faculty's most used technologies (such as possession of personal home technology tools, provision of a university office computer, connection to the Internet at a university, and connection to the Internet at home) for online teaching were also collected. Items pertaining to faculty perceptions of challenges associated with using online teaching tools in their teaching practice were also included in the second section of the survey. A 5-point Likert-scale was used for participant responses with 5=Always, 4=Mostly, 3=Moderate, 2=Seldom, and 1=Never. The findings of faculty demographic information and the type of technologies faculty uses most with online teaching that the quantitative findings of the ANOVA for the first part of the analysis, there were no significant differences identified for gender, faculty members' academic rank and experience, nationality, and contract types in relation to the use of university-provided resources for online teaching tools. However, significant differences were found among faculty members based on age, university departments or colleges, and the experience levels of faculty members for using university-provided resources for online teaching tools. In the second part of the ANOVA analysis, which involved comparisons of the variables, there were no significant differences found based on faculty members' age, university, academic rank or experience level, or gender to use a personal digital resource at home. However, the findings from the ANOVA analysis indicated that there were significant differences found for faculty and using personal digital resources. Differences were found between the three different university contract types. Specifically, faculty with non-renewable contracts were found to use personal resources more than those with renewable contracts. Additionally, differences were also found based on nationality, in that Saudi faculty use significantly more personal resources. For the use of online teaching and learning tool's part based on Decomposed Theory of Planned Behavior (DTPB) modal to the attitude, subjective norms, and perceived behavioral control. The attitude findings of the qualitative faculty members indicated that their choices to engage with online teaching tools were greatly influenced by the perceived usefulness of online teaching during COVID-19. This was related to their flexible and interactive nature. Additionally, the quantitative findings showed that the perceived usefulness was significantly impacted by faculty attitudes toward using online tools in their teaching practices. The findings that qualitative findings from this study revealed the individual intentions of faculty in terms of selecting online and digital tools for online instruction that was based on their assessments of expected difficulty toward the outcomes of intended behavior. However, the quantitative findings indicated that peer influence, student influence, and superior influence were significant factors affecting faculty members' subjective norms. Finally, the quantitative findings of perceived behavioral control indicated the significance of facilitating conditions, technology, and resources as factors that affect faculty members' behavioral control over online teaching in this study. The qualitative result indicated that faculty members were engaged in online teaching positively despite the difficulties and challenges and perceived significant usefulness in utilizing various online and digital teaching tools. / Doctor of Philosophy / This descriptive study investigated the factors and challenges influencing faculty member adoption of online teaching into teaching practice at Saudi universities. This study aims to (1) identify whether the differences that exist in Saudi faculty members' use of online tools can be associated with factors such as gender, age, academic rank, teaching experience, department or college, nationality, type of contract, possession of personal online and digital tools at home, provision of a university office with online and digital tools, connection to the Internet at a university, and connection to the Internet at home, (2) determine the perceived advantages and disadvantages for faculty members using online teaching in the instructional process, (3) determine perceived challenges for faculty members using online teaching in the instructional process. The parallel convergent mixed method was used as the methodology for this study and was conducted in three Saudi universities; Imam Abdulrahman bin Faisal University, King Faisal University, and University of Bisha. The total number of responses from the study instrument was about 124; Imam Abdulrahman bin Faisal University 49, King Faisal University 41, and the University of Bisha 34. The theoretical framework for this study was the Decomposed Theory of Planned Behavior (DTPB) modal. The collection of quantitative and qualitative data as convergent parallel mixed methods was in one phase and concurrently included close-ended and open-ended questions. However, both quantitative and qualitative findings indicated that their choices to engage with online teaching tools were greatly influenced by the perceived usefulness of online teaching during COVID-19 and the perceived usefulness was significantly impacted by faculty members' attitudes. The qualitative findings from this study revealed the individual intentions of faculty in terms of selecting online and digital tools for online instruction. This was based on their assessments of expected difficulty toward the outcomes of intended behavior (Yao et al., 2022). For example, faculty members indicated that they used online teaching tools because such tools were easy to operate and provided ample opportunity to interact with several students at the same time. However, faculty members also indicated perceived difficulty and complexity associated with online digital tools. On the other hand, quantitative findings indicated that peer influence, student influence, and superior influence were significant factors affecting faculty members' subjective norms. Finally, the findings from this study indicated that faculty members were engaged in online teaching positively despite the difficulties and challenges. However, they perceived significant usefulness in utilizing various online and digital teaching tools.

Thomas S. Kuhn claimed that the meanings of scientific terms change in theory changes or in scientific revolutions. In philosophy, meaning change has been taken as the source of a group of problems, such as untranslatability, incommensurability, and referential variance. For this reason, the majority of analytic philosophers have sought to deny that there can be meaning change by focusing on developing a theory of reference that would guarantee referential stability. A number of philosophers have also claimed that Kuhn’s view can be explained by the fact that he accepted and further developed many central tenets of logical empiricism. I maintain that the genesis of Kuhn’s meaning theorising lies in his historical approach and that his view of meaning change is justified. Later in his career he attempted to advance a theory of meaning and can be said to have had limited success in it. What is more, recent cognitive science has unexpectedly managed to shed light on Kuhn’s insights on the organisation of information in the mind, concept learning, and concept definition. Furthermore, although Kuhn’s critique of Putnam’s causal theory of reference has often been dismissed as irrelevant, he has a serious point to address. Kuhn thought that the causal theory that works so well with proper names cannot work with scientific terms. He held that conceptual categories are formed by similarity and dissimilarity relations; therefore, several features and not only one single property are needed for determination of extension. In addition, the causal theory requires universal substances as points of reference of scientific terms. Kuhn was a conceptualist, who held that universals do not exist as mind-independent entities and that mind-dependent family resemblance concepts serve the role of universals. Further, at the beginning of his career, Kuhn was interested in the question of what concepts or ideas are and how they change in their historical context. Although he did not develop his theorising on this issue, I demonstrate that this is a genuine problem in the philosophy of history. Finally, Kuhn argued that scientists cannot have access to truth in history because we cannot transcend our historical niche, and as a consequence, the truth of a belief cannot be a reason for theory choice. Instead of truth, we can rely on justification. I also discuss Kuhn’s idea that problem-solving is the main aim of science and show that this view can be incorporated into coherentist epistemology.

The semiconductor industry has decreased silicon-based device feature sizes dramatically over the last two decades for improved performance. However, current technology has approached the limit of achievable enhancement via this method. Therefore, other techniques, including introducing stress into the silicon structure, are being used to further advance device performance. While these methods produce successful results, there is not a proven reliable method for stress and strain measurements on the nanometer scale characteristic of these devices. The ability to correlate local strain values with processing parameters and device performance would allow for more rapid improvements and better process control. In this research, x-ray diffraction and convergent beam electron diffraction have been utilized to quantify the strain behavior of simple and complex strained silicon-based systems. While the stress relaxation caused by thinning of the strained structures to electron transparency complicates these measurements, it has been quantified and shows reasonable agreement with expected values. The relaxation values have been incorporated into the strain determination from relative shifts in the higher order Laue zone lines visible in convergent beam electron diffraction patterns. The local strain values determined using three incident electron beam directions with different degrees of tilt relative to the device structure have been compared and exhibit excellent agreement.

Unlike desert rodents from North America, Allenby’s gerbil (Gerbillus andersoni allenbyi) from the Negev Desert, Israel has evolved with snakes that do not have heat-sensitive sensory pits that enhance night vision. Does this history affect their ability to assess and respond to a snake that has this ability? As a test, we exposed gerbils to risk of predation from various predators, including snakes, owls, and foxes. The snakes included the Saharan horned viper (Cerastes cerastes) and the sidewinder rattlesnake (Crotalus cerastes). The former snake lacks sensory pits and shares a common evolutionary history with the gerbil. The latter snake, while convergent evolutionarily on the horned viper, has sensory pits and no prior history with the gerbil. The gerbils exploited depletable resource patches similarly, regardless of snake species and moon phase. While the gerbils did not respond to the novel snake as a greater threat than their familiar horned viper, the gerbils were cognizant that the novel predator was a threat. In response to both snakes, giving-up densities (GUDs; the amount of food left in a resource patch following exploitation) of the gerbils were higher in the bush than open microhabitat. In response to moonlight, GUDs were higher on full than on the new moon. Based on GUDs, the gerbils responded most to the risk of predation from the red fox, least from the two snake species, and intermediate for the barn owl. Keywords:

A ecomorfologia apresenta diferentes ramos, sendo a ecomorfologia comparada o ramo proposto neste trabalho, qual segue a análise das estruturas convergentes dos representantes das famílias africana Pantodontidae e neotropical Gasteropelecidae. Para tal, são analisadas e discutidas as pressões seletivas exercidas pelos ambientes muito similares encontrados nos pequenos córregos e igarapés localizados no interior da Floresta do Congo e Floresta Amazônica, onde vivem respectivamente as espécies africanas e neotropicais. Assim, foi possível identificar uma forte convergência adaptativa na musculatura das nadadeiras peitorais, uma vez que são adaptações aos saltos de longo alcance para fora dágua, característicos de todas as espécies analisadas, tratadas em conjunto por peixes-borboleta de água doce (Weist, 1995; Saidel et al., 2003). / The ecomorphology studies present different fields. The Comparative Ecomorphology, the field suggested at this work, follows the analyses of convergent structures found among Pantodontidae african families and Gasteropelecidae neotropical families. Due to that, we evaluated the selective pressures from similar aquatic environments, such as streams and small rivers. The analyses of african and neotropical species were done in relation to the Congo and Amazon Forest areas, respectively. In this context, we identified strong adaptive convergence in the musculature associated to the pectoral fins. These adaptations are related, in both studied cases, to the ability to jump long distandes out of the water (Weist, 1995; Saidel et al., 2003).

A necessidade constante de desenvolvimento de competências individuais e organizacionais atrelada a projetos de educação a distância (EAD) expande a possibilidade de acesso a programas de treinamento, formação e qualificação profissionais ofertados por instituições de ensino superior (IES) e outras organizações do sistema produtivo. Nota-se um grande progresso tecnológico cada vez mais disseminado no recente campo da EAD. Porém, essa modalidade de ensino é muito carente de estudos sistemáticos. Variáveis relacionadas ao perfil da clientela necessitam ser mais investigadas, como é o caso dos Estilos de Aprendizagem, que necessita de uma definição mais apurada, especialmente para garantir a qualidade dos instrumentos que se propõem a medir esse construto. Muitas vezes o seu conceito está relacionado com o conceito de Estratégias de Aprendizagem, sem grandes diferenciações entre eles. Além disso, a literatura indica que tais variáveis de características da clientela podem estar relacionadas com a Evasão em cursos na modalidade EAD. Nesse sentido, a presente pesquisa objetivou construir e verificar evidências de validade de um instrumento de medida de Estilos de Aprendizagem, bem como realizar a validade convergente com o instrumento de Estratégias de Aprendizagem, além de propor uma discussão conceitual acerca dos Estilos de Aprendizagem. Ao final desse estudo, o instrumento de Estilos de Aprendizagem foi construído, passou por validação semântica, por juízes e foram verificadas evidências de validade estatística. Foi demonstrado também que os alunos que fizeram mais uso das Estratégias de Aprendizagem Autorregulatórias, bem como das Estratégias Comportamentais e valorizam mais os aspectos do ambiente no quais realiza os seus estudos (ou seja, possuem mais Preferências Ambientais) tendem a não abandonar o curso. A validação convergente entre os instrumentos de Estilos de Aprendizagem e Estratégias de Aprendizagem demonstraram que os instrumentos refletem o histórico de relacionamento entre esses conceitos. Muitos fatores de Estratégias de Aprendizagem se relacionam com o instrumento de Estilos de Aprendizagem. Os resultados também possibilitaram uma definição operacional de Estilos de Aprendizagem no campo da Psicologia Organizacional e do Trabalho (POT). Para pesquisas futuras, recomenda-se o uso de técnicas estatísticas mais robustas, como o uso de Análise Fatorial Confirmatória, bem como a Modelagem de Equações Estruturais, que poderiam mensurar com maior exatidão o quanto os Estilos e as Estratégias de Aprendizagem influenciam a Evasão em Ações Educacionais Ofertadas a Distância em contexto de IES. / The constant need to develop individual and organizational competences linked to e-learning projects expands the possibility of access to professional training and qualification programs offered by higher education institutions (HEIs) and other organizations of the productive system. A great technological progress is becoming increasingly widespread in this recent e-learning field. However, this type of education is very lacking in systematic studies. Variables related to the customer profile needs to be further investigated, like the Learning Styles variable. This last requires a more precise definition, especially to ensure the quality of the instruments used to measure this construct. The Learning Styles concept is often related to the Strategy Styles concept without mentioning the proper differences between them. Besides that, the literature indicates that such costumers characteristics variables may be related to the Evasion in e-learning courses. This research aimed to carry out the conceptual analysis of Learning Styles through the construction and verification of validity evidence of a measuring instrument and the convergent validity with Learning Strategies. The Learning Styles instrument was built, underwent semantic validation by judges and evidence of statistical validity were verified. It was also shown that students who made more use of Self-Regulatory Learning Strategies, as well as Behavioral Strategies and value the aspects of the environment in which they realize its studies (ie, have more Environmental Preferences) tend not to leave the course. The convergent validity between Learning Styles and Learning Strategies instruments showed that the instruments reflect the historical relationship between these concepts. Many aspects of Learning Strategies are also related to the Learning Styles aspects. The results showed an adequate definition of Learning Styles in the field of Organizational and Work Psychology (OWP). For future research, it is recommending the use of more consistent statistical techniques such the Confirmatory Factor Analysis as well as Structural Equation Modeling, which could measure more accurately how the Styles and Learning Strategies influence the Evasion in e-learning in the higher education institutions context.