867 resultados para Limit of meaning of a Scientific Theory
Desorption isotherms and thermodynamics properties of anchovy in natura and enzymatic modified paste
Resumo:
The thermodynamic properties of anchovy fillets and enzymatic modified pastes in two hydrolysis degrees (3% HD and 14% HD), at 50, 60 and 70 C were evaluated. The GAB model was used to calculate the values of the monolayer moisture content and the thermodynamic properties of the samples. The enzymatic modification led to the increases of the superficial area and differential enthalpies, and decrease of the differential entropies in relation the samples in natura. The enthalpy–entropy compensation showed that the process was controlled by the enthalpy, it was only spontaneous for the samples in natura. Pore size decreased with enzymatic modification, and all samples were in the limit of region between micropores and mesopores (<2 nm) for moisture content of 15%, and mesopores (from 2 to 50 nm) to moisture content above 15%.
Resumo:
A detailed non-equilibrium state diagram of shape-anisotropic particle fluids is constructed. The effects of particle shape are explored using Naive Mode Coupling Theory (NMCT), and a single particle Non-linear Langevin Equation (NLE) theory. The dynamical behavior of non-ergodic fluids are discussed. We employ a rotationally frozen approach to NMCT in order to determine a transition to center of mass (translational) localization. Both ideal and kinetic glass transitions are found to be highly shape dependent, and uniformly increase with particle dimensionality. The glass transition volume fraction of quasi 1- and 2- dimensional particles fall monotonically with the number of sites (aspect ratio), while 3-dimensional particles display a non-monotonic dependence of glassy vitrification on the number of sites. Introducing interparticle attractions results in a far more complex state diagram. The ideal non-ergodic boundary shows a glass-fluid-gel re-entrance previously predicted for spherical particle fluids. The non-ergodic region of the state diagram presents qualitatively different dynamics in different regimes. They are qualified by the different behaviors of the NLE dynamic free energy. The caging dominated, repulsive glass regime is characterized by long localization lengths and barrier locations, dictated by repulsive hard core interactions, while the bonding dominated gel region has short localization lengths (commensurate with the attraction range), and barrier locations. There exists a small region of the state diagram which is qualified by both glassy and gel localization lengths in the dynamic free energy. A much larger (high volume fraction, and high attraction strength) region of phase space is characterized by short gel-like localization lengths, and long barrier locations. The region is called the attractive glass and represents a 2-step relaxation process whereby a particle first breaks attractive physical bonds, and then escapes its topological cage. The dynamic fragility of fluids are highly particle shape dependent. It increases with particle dimensionality and falls with aspect ratio for quasi 1- and 2- dimentional particles. An ultralocal limit analysis of the NLE theory predicts universalities in the behavior of relaxation times, and elastic moduli. The equlibrium phase diagram of chemically anisotropic Janus spheres and Janus rods are calculated employing a mean field Random Phase Approximation. The calculations for Janus rods are corroborated by the full liquid state Reference Interaction Site Model theory. The Janus particles consist of attractive and repulsive regions. Both rods and spheres display rich phase behavior. The phase diagrams of these systems display fluid, macrophase separated, attraction driven microphase separated, repulsion driven microphase separated and crystalline regimes. Macrophase separation is predicted in highly attractive low volume fraction systems. Attraction driven microphase separation is charaterized by long length scale divergences, where the ordering length scale determines the microphase ordered structures. The ordering length scale of repulsion driven microphase separation is determined by the repulsive range. At the high volume fractions, particles forgo the enthalpic considerations of attractions and repulsions to satisfy hard core constraints and maximize vibrational entropy. This results in site length scale ordering in rods, and the sphere length scale ordering in Janus spheres, i.e., crystallization. A change in the Janus balance of both rods and spheres results in quantitative changes in spinodal temperatures and the position of phase boundaries. However, a change in the block sequence of Janus rods causes qualitative changes in the type of microphase ordered state, and induces prominent features (such as the Lifshitz point) in the phase diagrams of these systems. A detailed study of the number of nearest neighbors in Janus rod systems reflect a deep connection between this local measure of structure, and the structure factor which represents the most global measure of order.
Resumo:
Tese de Doutoramento, Ciências do Ambiente (Ordenamento do Território), 5 de Abril de 2013, Universidade dos Açores.
Resumo:
Breast cancer is one of the most prevalent forms of cancer in women. Despite all recent advances in early diagnosis and therapy, mortality data is not decreasing. This is an outcome of the inexistence of validated serum biomarkers allowing an early prognosis, out coming from the limited understanding of the natural history of the disease. In this context, miRNAs have been attracting a special interest throughout the scientific community as promising biomarkers in the early diagnosis of cancer. In breast cancer, several miRNAs and their levels of expression are significantly different between normal tissue and tissue with neoplasia, as well as between different molecular subtypes of breast cancer, also associated with prognosis. Thus, this these presents a meta-analysis that allows identifying a reliable miRNA biomarker for the early detection of breast cancer. In this, miRNA-155 was identified as the best one and an electrochemical biosensor was developed for its detection in serum samples. The biosensor was assembled by following three button-up stages: (1) the complementary miRNA sequence thiol terminated (anti-miRNA-155) was immobilized on a commercial gold screen-printed electrode (Au-SPE), followed by (2) blocking non-specific binding with mercaptosuccinic acid and by (3) miRNA hybridization. The biosensor was able to detect miRNA concentrations lying in the 10-18 mol/L (aM) range, displaying a linear response from 10 aM to 1nM. The device showed a limit of detection of 5.7 aM in human serum samples and good selectivity against other biomolecules in serum, such as cancer antigen CA-15.3 and bovine serum albumin (BSA). Overall, this simple and sensitive strategy is a promising approach for the quantitative and/or simultaneous analysis of multiple miRNA in physiological fluids, aiming at further biomedical research devoted to biomarker monitoring and point-of-care diagnosis.
Resumo:
La notion de chez-soi est porteuse d’un imaginaire foisonnant et génère un grand intérêt dans notre culture et société. Bien qu’elle soit une considération importante pour la plupart d’entre nous, l’architecte occupe une position privilégiée qui lui permette d’agir sur le chez-soi de manière significative et tangible. La présente recherche explore le concept du chez-soi tel qu’étudié par les architectes et non-architectes de manière à comprendre son impact sur la création du lieu et sur la construction des environnements domestiques en Amérique du nord. Un regard porté sur les connotations entre espace et lieu, à travers la temporalité, les comportements et les perspectives sociales, supporte l’épistémologie du chez-soi comme un élément important des théories et pratiques de design contemporain. Le démantèlement hypothétique d’un espace en ses composantes suppose que les dispositifs architecturaux peuvent être modelés de manière à ce qu’ils opèrent un transfert depuis la maison, en tant qu’élément physique, vers le domaine psychologique du chez-soi. Afin d’élargir la maniabilité des éléments constitutifs du bâtiment et de son environnement, six thèmes sont appliqués à trois champs de données. Les six thèmes, qui incluent l’entre-deux, la limite, la voie, le nœud, le détail et la représentation, illustrent des moments architecturaux déterminants, potentiellement présents à l’intérieur et à l’extérieur du projet domestique et qui transforment les comportements physiques et psychiques. Depuis la pratique normalisée du logement social et abordable au Canada, une analyse de photographies de maisons abordables existantes, du discours critique sur cette typologie et de projets de recherche-création conduits par des étudiants en architecture, révèle le caractère opérationnel de la notion de chez-soi et consolide les valeurs de communauté et de frontière. L’objectif premier de la recherche est d’avancer la production de connaissances en architecture par l’exploration de la notion de chezsoi dans l’enseignement, la recherche et le design. L’approche fonctionnaliste vis-à-vis le < penser > en design, place l’usager au centre de l’environnement domestique, soutient la proposition que le chezsoi donne sens et utilité au logement, et renforce la responsabilité éthique de l’architecte à faire de cette notion une partie intégrante de la réalité quotidienne.
Resumo:
Race as a biological category has a long and troubling history as a central ordering concept in the life and human sciences. The mid-twentieth century has been marked as the point where biological concepts of race began to disappear from science. However, biological definitions of race continue to penetrate scientific understandings and uses of racial concepts. Using the theoretical frameworks of critical race theory and science and technology studies and an in-depth case study of the discipline of immunology, this dissertation explores the appearance of a mid-century decline of concepts of biological race in science. I argue that biological concepts of race did not disappear in the middle of the twentieth century but were reconfigured into genetic language. In this dissertation I offer a periodization of biological concepts of race. Focusing on continuities and the effects of contingent events, I compare how biological concepts of race articulate with racisms in each period. The discipline of immunology serves as a case study that demonstrates how biological concepts of race did not decline in the postwar era, but were translated into the language of genetics and populations. I argue that the appearance of a decline was due to events both internal and external to the science of immunology. By framing the mid-twentieth century disappearance of race in science as the triumph of an antiracist racial project of science, it allows us to more clearly see the more recent resurgence of race in science as a recycling of older themes and tactics from the racist science projects of the past.
Resumo:
320 p.
Resumo:
In knowledge technology work, as expressed by the scope of this conference, there are a number of communities, each uncovering new methods, theories, and practices. The Library and Information Science (LIS) community is one such community. This community, through tradition and innovation, theories and practice, organizes knowledge and develops knowledge technologies formed by iterative research hewn to the values of equal access and discovery for all. The Information Modeling community is another contributor to knowledge technologies. It concerns itself with the construction of symbolic models that capture the meaning of information and organize it in ways that are computer-based, but human understandable. A recent paper that examines certain assumptions in information modeling builds a bridge between these two communities, offering a forum for a discussion on common aims from a common perspective. In a June 2000 article, Parsons and Wand separate classes from instances in information modeling in order to free instances from what they call the “tyranny” of classes. They attribute a number of problems in information modeling to inherent classification – or the disregard for the fact that instances can be conceptualized independent of any class assignment. By faceting instances from classes, Parsons and Wand strike a sonorous chord with classification theory as understood in LIS. In the practice community and in the publications of LIS, faceted classification has shifted the paradigm of knowledge organization theory in the twentieth century. Here, with the proposal of inherent classification and the resulting layered information modeling, a clear line joins both the LIS classification theory community and the information modeling community. Both communities have their eyes turned toward networked resource discovery, and with this conceptual conjunction a new paradigmatic conversation can take place. Parsons and Wand propose that the layered information model can facilitate schema integration, schema evolution, and interoperability. These three spheres in information modeling have their own connotation, but are not distant from the aims of classification research in LIS. In this new conceptual conjunction, established by Parsons and Ward, information modeling through the layered information model, can expand the horizons of classification theory beyond LIS, promoting a cross-fertilization of ideas on the interoperability of subject access tools like classification schemes, thesauri, taxonomies, and ontologies. This paper examines the common ground between the layered information model and faceted classification, establishing a vocabulary and outlining some common principles. It then turns to the issue of schema and the horizons of conventional classification and the differences between Information Modeling and Library and Information Science. Finally, a framework is proposed that deploys an interpretation of the layered information modeling approach in a knowledge technologies context. In order to design subject access systems that will integrate, evolve and interoperate in a networked environment, knowledge organization specialists must consider a semantic class independence like Parsons and Wand propose for information modeling.
Resumo:
Describes four waves of Ranganathan’s dynamic theory of classification. Outlines components that distinguish each wave, and porposes ways in which this understanding can inform systems design in the contemporary environment, particularly with regard to interoperability and scheme versioning. Ends with an appeal to better understanding the relationship between structure and semantics in faceted classification schemes and similar indexing languages.
Resumo:
Metadata that is associated with either an information system or an information object for purposes of description, administration, legal requirements, technical functionality, use and usage, and preservation, plays a critical role in ensuring the creation, management, preservation and use and re-use of trustworthymaterials, including records. Recordkeeping1 metadata, of which one key type is archival description, plays a particularly important role in documenting the reliability and authenticity of records and recordkeeping systemsas well as the various contexts (legal-administrative, provenancial, procedural, documentary, and technical) within which records are created and kept as they move across space and time. In the digital environment, metadata is also the means by which it is possible to identify how record components – those constituent aspects of a digital record that may be managed, stored and used separately by the creator or the preserver – can be reassembled to generate an authentic copy of a record or reformulated per a user’s request as a customized output package.Issues relating to the creation, capture, management and preservation of adequate metadata are, therefore, integral to any research study addressing the reliability and authenticity of digital entities, regardless of the community, sector or institution within which they are being created. The InterPARES 2 Description Cross-Domain Group (DCD) examined the conceptualization, definitions, roles, and current functionality of metadata and archival description in terms of requirements generated by InterPARES 12. Because of the needs to communicate the work of InterPARES in a meaningful way across not only other disciplines, but also different archival traditions; to interface with, evaluate and inform existing standards, practices and other research projects; and to ensure interoperability across the three focus areas of InterPARES2, the Description Cross-Domain also addressed its research goals with reference to wider thinking about and developments in recordkeeping and metadata. InterPARES2 addressed not only records, however, but a range of digital information objects (referred to as “entities” by InterPARES 2, but not to be confused with the term “entities” as used in metadata and database applications) that are the products and by-products of government, scientific and artistic activities that are carried out using dynamic, interactive or experiential digital systems. The nature of these entities was determined through a diplomatic analysis undertaken as part of extensive case studies of digital systems that were conducted by the InterPARES 2 Focus Groups. This diplomatic analysis established whether the entities identified during the case studies were records, non-records that nevertheless raised important concerns relating to reliability and authenticity, or “potential records.” To be determined to be records, the entities had to meet the criteria outlined by archival theory – they had to have a fixed documentary format and stable content. It was not sufficient that they be considered to be or treated as records by the creator. “Potential records” is a new construct that indicates that a digital system has the potential to create records upon demand, but does not actually fix and set aside records in the normal course of business. The work of the Description Cross-Domain Group, therefore, addresses the metadata needs for all three categories of entities.Finally, since “metadata” as a term is used today so ubiquitously and in so many different ways by different communities, that it is in peril of losing any specificity, part of the work of the DCD sought to name and type categories of metadata. It also addressed incentives for creators to generate appropriate metadata, as well as issues associated with the retention, maintenance and eventual disposition of the metadata that aggregates around digital entities over time.
Resumo:
Introduction: The training of nursing students in the context of clinical practice, is characterized by educational experiences, subject to various emotional stress (stress, ambivalence, frustration, conflict), sometimes making it very vulnerable student.However not all students use the same strategies minimizing their meanings and negative effects on the level of your health and well-being Objetiv:To analyze the perception that nursing students have about the determinants of their health status and well-being in clinical practice Methods: Exploratory research Results:The results reveal the complexity of the teaching / learning process in clinical practice, identified determinants that limit and / or promote health and well-being of students, or not contributing to their motivation, self-confidence and learning. All students value the presence of the following dimensions: affective-emotional (humanization in learning experiences); relational dynamics (interactions developed with all stakeholders); methods used (professional competence of the clinical supervisor and teacher); school curriculum (adaptation of learning in theory); socialization to the profession (become nurse).Conclusions: The results indicate, that although all students evidencing the dimensions described as fundamental to learning in clinical practice, the study results are dichotomous and ambivalent. Students 2nd and 3ºanos refer a low perception in clinical practice, the indicated dimensions, and for these source of concern and uncertainty in learning, such as limiting their health condition and well-being. For students of the 4th year, these dimensions are percecionadas as gifts, and sources of motivation, learning and catalysts such as promoting their health and well-being.
Resumo:
In practical terms, conceptual modeling is at the core of systems analysis and design. The plurality of modeling methods available has however been regarded as detrimental, and as a strong indication that a common view or theoretical grounding of modeling is wanting. This theoretical foundation must universally address all potential matters to be represented in a model, which consequently suggested ontology as the point of departure for theory development. The Bunge–Wand–Weber (BWW) ontology has become a widely accepted modeling theory. Its application has simultaneously led to the recognition that, although suitable as a meta-model, the BWW ontology needs to be enhanced regarding its expressiveness in empirical domains. In this paper, a first step in this direction has been made by revisiting BUNGE’s ontology, and by proposing the integration of a “hierarchy of systems” in the BWW ontology for accommodating domain specific conceptualizations.
Resumo:
This paper explores how people communicate in reference to local interests and suggests information and communication technology (ICT) design for enhancement of local community networks. Qualitative data was gathered from participant observations of local community collective action and open interviews with active community members. Data analysis revealed concepts, leading to categories in relation to local interactions and interests. Design suggestions consider introducing people to local community private-strategic activity via public displays that indicate simple entry points to active participation, and creating information collections according to local community perspectives for long-term reference.
Resumo:
In the context of a multi-paper special issue of TVNM on the future of media studies, this paper traces the tradition of ‘active audience’ theory in TV scholarship, arguing that it has much to offer in the study of new digital media, especially an approach to user-created content and dynamics of change. The paper argues for a ‘cultural science’ approach to ‘active audiences’ in order to analyse and understand how non-professionals and consumers contribute to the growth of knowledge in complex open media systems.
Resumo:
This study explores teenager perceptions towards advertising in the online social networking environment. The future of online social networking sites is dependant upon the continued support of advertisers in this new medium, which is linked to the acceptance of advertising on these sites by their targeted audience. This exploratory study used the qualitative research methods of focus groups and in-depth personal interviews to gain insights from the teenager participants. The literature review in Chapter Two examined the previous research into advertising theories, consumer attitudes and issues such as advertising avoidance, advertising as a service and trust and privacy in the online social networking environment. The teenage consumer was also examined as were the influences of social identity theory. From this literature review eleven propositions were formed which provided a structure to the analysis of the research. Chapter Three outlined the multi-method research approach of using focus groups and in-depth interviews. The key findings were outlined in Chapter Four and Chapter Five provides discussion regarding these findings and the implications for theory and advertising practice. The main findings from this study suggest that teenagers have very high levels of advertising avoidance and are sceptical towards advertising on their online social networking sites. They have an inherent distrust of commercial messages in the online social networking environment; however they are extremely trusting with the information that they disclose online. They believe that if their site is classified as private, then the information disclosed on this site is not accessible to anyone. The study explores the reasons behind these views. This research has resulted in the identification of seven motivations behind online social networking use. A new model of advertising avoidance in the online social networking environment is also presented and discussed. This model makes a contribution towards filling the gap in available research on online social networking sites and advertising perception. The findings of this study have also resulted in the identification of the characteristics of online social networking sites as an advertising medium. The newness of online social networking sites coupled with the enthusiastic adoption of online social networking by the teenage demographic means that this exploratory study will be of interest to both academics and practitioners alike.