819 resultados para Nature study
Resumo:
To identify susceptibility loci for ankylosing spondylitis, we undertook a genome-wide association study in 2,053 unrelated ankylosing spondylitis cases among people of European descent and 5,140 ethnically matched controls, with replication in an independent cohort of 898 ankylosing spondylitis cases and 1,518 controls. Cases were genotyped with Illumina HumHap370 genotyping chips. In addition to strong association with the major histocompatibility complex (MHC; P 10 800), we found association with SNPs in two gene deserts at 2p15 (rs10865331; combined P = 1.9 × 10 19) and 21q22 (rs2242944; P = 8.3 × 10 20), as well as in the genes ANTXR2 (rs4333130; P = 9.3 × 10 8) and IL1R2 (rs2310173; P = 4.8 × 10 7). We also replicated previously reported associations at IL23R (rs11209026; P = 9.1 × 10 14) and ERAP1 (rs27434; P = 5.3 × 10 12). This study reports four genetic loci associated with ankylosing spondylitis risk and identifies a major role for the interleukin (IL)-23 and IL-1 cytokine pathways in disease susceptibility. © 2010 Nature America, Inc. All rights reserved.
Resumo:
Copy number variants (CNVs) account for a major proportion of human genetic polymorphism and have been predicted to have an important role in genetic susceptibility to common disease. To address this we undertook a large, direct genome-wide study of association between CNVs and eight common human diseases. Using a purpose-designed array we typed 19,000 individuals into distinct copy-number classes at 3,432 polymorphic CNVs, including an estimated 50% of all common CNVs larger than 500 base pairs. We identified several biological artefacts that lead to false-positive associations, including systematic CNV differences between DNAs derived from blood and cell lines. Association testing and follow-up replication analyses confirmed three loci where CNVs were associated with diseaseIRGM for Crohns disease, HLA for Crohns disease, rheumatoid arthritis and type 1 diabetes, and TSPAN8 for type 2 diabetesalthough in each case the locus had previously been identified in single nucleotide polymorphism (SNP)-based studies, reflecting our observation that most common CNVs that are well-typed on our array are well tagged by SNPs and so have been indirectly explored through SNP studies. We conclude that common CNVs that can be typed on existing platforms are unlikely to contribute greatly to the genetic basis of common human diseases. © 2010 Macmillan Publishers Limited. All rights reserved.
Resumo:
Elevated blood pressure is a common, heritable cause of cardiovascular disease worldwide. To date, identification of common genetic variants influencing blood pressure has proven challenging. We tested 2.5 million genotyped and imputed SNPs for association with systolic and diastolic blood pressure in 34,433 subjects of European ancestry from the Global BPgen consortium and followed up findings with direct genotyping (N 71,225 European ancestry, N 12,889 Indian Asian ancestry) and in silico comparison (CHARGE consortium, N = 29,136). We identified association between systolic or diastolic blood pressure and common variants in eight regions near the CYP17A1 (P = 7 × 10 24), CYP1A2 (P = 1 × 10 23), FGF5 (P = 1 × 10 21), SH2B3 (P = 3 × 10 18), MTHFR (P = 2 × 10 13), c10orf107 (P = 1 × 10 9), ZNF652 (P = 5 × 10 9) and PLCD3 (P = 1 × 10 8) genes. All variants associated with continuous blood pressure were associated with dichotomous hypertension. These associations between common variants and blood pressure and hypertension offer mechanistic insights into the regulation of blood pressure and may point to novel targets for interventions to prevent cardiovascular disease.
Resumo:
Ulcerative colitis is a common form of inflammatory bowel disease with a complex etiology. As part of the Wellcome Trust Case Control Consortium 2, we performed a genome-wide association scan for ulcerative colitis in 2,361 cases and 5,417 controls. Loci showing evidence of association at P 1 × 10 5 were followed up by genotyping in an independent set of 2,321 cases and 4,818 controls. We find genome-wide significant evidence of association at three new loci, each containing at least one biologically relevant candidate gene, on chromosomes 20q13 (HNF4A; P = 3.2 × 10 17), 16q22 (CDH1 and CDH3; P = 2.8 × 10 8) and 7q31 (LAMB1; P = 3.0 × 10 8). Of note, CDH1 has recently been associated with susceptibility to colorectal cancer, an established complication of longstanding ulcerative colitis. The new associations suggest that changes in the integrity of the intestinal epithelial barrier may contribute to the pathogenesis of ulcerative colitis. © 2009 Nature America, Inc. All rights reserved.
Resumo:
A detailed investigation of Y0.5Ca0.5MnO3 with a very small radius of the A-site cations ([r(A)] approximate to 1.13 Angstrom reveals the occurrence of a charge-ordering transition in the paramagnetic state, at a relatively high temperature of 260 K. The orthorhombic lattice distortion, as measured by the dimensionless index D, is large (similar to 1.75%) over the entire 300-100 K range, but the antiferromagnetic interactions become prominent only at low temperatures (< 160 K). The charge-ordering gap in Y0.5Ca0.5MnO3, measured by low-temperature vacuum tunnelling spectroscopy, is large (similar to 0.5 eV) and the charge-ordered state is unaffected by the application of a magnetic field of 6 T. The study indicates that the nature of charge-ordering in Y0.5Ca0.5MnO3 which is dominated by the cooperative Jahn-Teller effect and the associated lattice distortion is distinctly different from analogous manganates with larger [r(A)].
Resumo:
Background: Haemodialysis nurses form long term relationships with patients in a technologically complex work environment. Previous studies have highlighted that haemodialysis nurses face stressors related to the nature of their work and also their work environments leading to reported high levels of burnout. Using Kanters (1997) Structural Empowerment Theory as a guiding framework, the aim of this study was to explore the factors contributing to satisfaction with the work environment, job satisfaction, job stress and burnout in haemodialysis nurses. Methods: Using a sequential mixed-methods design, the first phase involved an on-line survey comprising demographic and work characteristics, Brisbane Practice Environment Measure (B-PEM), Index of Work Satisfaction(IWS), Nursing Stress Scale (NSS) and the Maslach Burnout Inventory (MBI). The second phase involved conducting eight semi-structured interviews with data thematically analyzed. Results: From the 417 nurses surveyed the majority were female (90.9 %), aged over 41 years of age (74.3 %), and 47.4 % had worked in haemodialysis for more than 10 years. Overall the work environment was perceived positively and there was a moderate level of job satisfaction. However levels of stress and emotional exhaustion (burnout) were high. Two themes, ability to care and feeling successful as a nurse, provided clarity to the level of job satisfaction found in phase 1. While two further themes, patients as quasi-family and intense working teams, explained why working as a haemodialysis nurse was both satisfying and stressful. Conclusions: Nurse managers can use these results to identify issues being experienced by haemodialysis nurses working in the unit they are supervising.
Resumo:
Findings from numerous quantitative studies suggest that spouses of patients undergoing Coronary Artery Bypass (CAB) surgery experience both physical and emotional stress before and after their partner's surgery. Such studies have contributed to our understanding of the spouses' experiences, however they have largely failed to capture the qualitative experience of what it is like to be a spouse of a partner who has undergone CAB surgery. The objective of this study was to describe the experience of spouses of patients who had recently undergone CAB surgery. This study was guided by Husserl's phenomenological approach to qualitative research. In accordance with the nature of phenomenological research the number of participants necessarily needs to be small because phenomenology values the unique experience of individuals. Therefore this study gathered data from four participants utilising open ended indepth interviews. The method of analysis was adapted from Amedeo Giorgi's five step empirical phenomenological process which brackets preconceived notions, reducing participants' accounts to the essential essence or meanings. Numerous themes common to each of the spouses emerged. These included: seeking information; the necessity for rapid decision making; playing guardian; a desire to debrief with their partner and lastly, uncertainty of their future role. This study has attempted to understand the phenomena of the spouse's experience and in doing so, believe that we now have a better understanding and insight into the needs of spouses of CAB surgery patients. This has added another dimension to our existing body of knowledge and further facilitates holistic patient care.
Resumo:
This paper deals with new results obtained in regard to the reconstruction properties of side-band Fresnel holograms (SBFH) of self-imaging type objects (for example, gratings) as compared with those of general objects. The major finding is that a distribution I2, which appears on the real-image plane along with the conventional real-image I1, remains a 2Z distribution (where 2Z is the axial distance between the object and its self-imaging plane) under a variety of situations, while its nature and focusing properties differ from one situation to another. It is demonstrated that the two distributions I1 and I2 can be used in the development of a novel technique for image subtraction.
Resumo:
The present study provides a usage-based account of how three grammatical structures, declarative content clauses, interrogative content clause and as-predicative constructions, are used in academic research articles. These structures may be used in both knowledge claims and citations, and they often express evaluative meanings. Using the methodology of quantitative corpus linguistics, I investigate how the culture of the academic discipline influences the way in which these constructions are used in research articles. The study compares the rates of occurrence of these grammatical structures and investigates their co-occurrence patterns in articles representing four different disciplines (medicine, physics, law, and literary criticism). The analysis is based on a purpose-built 2-million-word corpus, which has been part-of-speech tagged. The analysis demonstrates that the use of these grammatical structures varies between disciplines, and further shows that the differences observed in the corpus data are linked with differences in the nature of knowledge and the patterns of enquiry. The constructions in focus tend to be more frequently used in the soft disciplines, law and literary criticism, where their co-occurrence patterns are also more varied. This reflects both the greater variety of topics discussed in these disciplines, and the higher frequency of references to statements made by other researchers. Knowledge-building in the soft fields normally requires a careful contextualisation of the arguments, giving rise to statements reporting earlier research employing the constructions in focus. In contrast, knowledgebuilding in the hard fields is typically a cumulative process, based on agreed-upon methods of analysis. This characteristic is reflected in the structure and contents of research reports, which offer fewer opportunities for using these constructions.
Resumo:
E.S.R. investigations of γ-irradiated ferroelectric Sodium ammonium selenate, NaNH4SeO4•2H2O and its deuteriated analogue in powder and single crystal forms have led to a deeper understanding of the nature of the ferroelectric transition of 180 K. A number of paramagnetic species formed due to γ-irradiation have been identified on the basis of their g-factors and hyperfine features from 77Se. The radical SeO4 has been used as a microprobe in studying the phase transition.
Resumo:
In this study I consider what kind of perspective on the mind body problem is taken and can be taken by a philosophical position called non-reductive physicalism. Many positions fall under this label. The form of non-reductive physicalism which I discuss is in essential respects the position taken by Donald Davidson (1917-2003) and Georg Henrik von Wright (1916-2003). I defend their positions and discuss the unrecognized similarities between their views. Non-reductive physicalism combines two theses: (a) Everything that exists is physical; (b) Mental phenomena cannot be reduced to the states of the brain. This means that according to non-reductive physicalism the mental aspect of humans (be it a soul, mind, or spirit) is an irreducible part of the human condition. Also Davidson and von Wright claim that, in some important sense, the mental aspect of a human being does not reduce to the physical aspect, that there is a gap between these aspects that cannot be closed. I claim that their arguments for this conclusion are convincing. I also argue that whereas von Wright and Davidson give interesting arguments for the irreducibility of the mental, their physicalism is unwarranted. These philosophers do not give good reasons for believing that reality is thoroughly physical. Notwithstanding the materialistic consensus in the contemporary philosophy of mind the ontology of mind is still an uncharted territory where real breakthroughs are not to be expected until a radically new ontological position is developed. The third main claim of this work is that the problem of mental causation cannot be solved from the Davidsonian - von Wrightian perspective. The problem of mental causation is the problem of how mental phenomena like beliefs can cause physical movements of the body. As I see it, the essential point of non-reductive physicalism - the irreducibility of the mental - and the problem of mental causation are closely related. If mental phenomena do not reduce to causally effective states of the brain, then what justifies the belief that mental phenomena have causal powers? If mental causes do not reduce to physical causes, then how to tell when - or whether - the mental causes in terms of which human actions are explained are actually effective? I argue that this - how to decide when mental causes really are effective - is the real problem of mental causation. The motivation to explore and defend a non-reductive position stems from the belief that reductive physicalism leads to serious ethical problems. My claim is that Davidson's and von Wright's ultimate reason to defend a non-reductive view comes back to their belief that a reductive understanding of human nature would be a narrow and possibly harmful perspective. The final conclusion of my thesis is that von Wright's and Davidson's positions provide a starting point from which the current scientistic philosophy of mind can be critically further explored in the future.
Resumo:
It is now widely acknowledged that student mental well-being is a critical factor in the tertiary student learning experience and is important to student learning success. The issue of student mental well-being also has implications for effective student transition out of university and into the world of work. It is therefore vital that intentional strategies are adopted by universities both within the formal curriculum, and outside it, to promote student well-being and to work proactively and preventatively to avoid a decline in student psychological well-being. This paper describes how the Queensland University of Technology Law School is using animation to teach students about the importance for their learning success of the protection of their mental well-being. Mayer and Moreno (2002) define an animation as an external representation with three main characteristics: (1) it is a pictorial representation, (2) it depicts apparent movement, and (3) it consists of objects that are artificially created through drawing or some other modelling technique. Research into the effectiveness of animation as a tool for tertiary student learning engagement is relatively new and growing field of enquiry. Nash argues, for example, that animations provide a “rich, immersive environment [that] encourages action and interactivity, which overcome an often dehumanizing learning management system approach” (Nash, 2009, 25). Nicholas states that contemporary millennial students in universities today, have been immersed in animated multimedia since their birth and in fact need multimedia to learn and communicate effectively (2008). However, it has also been established, for example through the work of Lowe (2003, 2004, 2008) that animations can place additional perceptual, attentional, and cognitive demands on students that they are not always equipped to cope with. There are many different genres of animation. The dominant style of animation used in the university learning environment is expository animation. This approach is a useful tool for visualising dynamic processes and is used to support student understanding of subjects and themes that might otherwise be perceived as theoretically difficult and disengaging. It is also a form of animation that can be constructed to avoid any potential negative impact on cognitive load that the animated genre might have. However, the nature of expository animation has limitations for engaging students, and can present as clinical and static. For this reason, the project applied Kombartzky, Ploetzner, Schlag, and Metz’s (2010) cognitive strategy for effective student learning from expository animation, and developed a hybrid form of animation that takes advantage of the best elements of expository animation techniques along with more engaging short narrative techniques. First, the paper examines the existing literature on the use of animation in tertiary educational contexts. Second, the paper describes how animation was used at QUT Law School to teach students about the issue of mental well-being and its importance to their learning success. Finally, the paper analyses the potential of the use of animation, and of the cognitive strategy and animation approach trialled in the project, as a teaching tool for the promotion of student learning about the importance of mental well-being.
Resumo:
This is an ethnographic case study of the creation and emergence of a playworld – a pedagogical approach aimed at promoting children’s development and learning in early education settings through the use of play and drama. The data was collected in a Finnish experimental mixed-age elementary school classroom in the school year 2003-2004. In the playworld students and teachers explore different social and cultural phenomena through taking on the roles of characters from a story or a piece of literature and acting inside the frames of an improvised plot. The thesis takes under scrutiny the notion of agency in education. It produces theoretically grounded empirical knowledge of the ways in which children struggle to become recognized and agentive actors in early education settings and how their agency develops in their interaction with adults. The study builds on the activity theoretical and sociocultural tradition and develops a methodological framework called video-based narrative interaction analysis for studying student agency as developing over time but manifesting through the situational material and discursive local interactions. The research questions are: 1. What are the children’s ways of enacting their agency in the playworld? 2. How do the children’s agentive actions change and develop over the spring? 3. What are the potentials and challenges of the playworld for promoting student agency? 4. How do the teachers and the children deal with the contradiction between control and agency in the playworld? The study consists of a summary part and four empirical articles which each have a particular viewpoint. Articles I and II deal with individual students’ paths to agency. In Article I the focus is on the role of resistance and questioning in enabling important spaces for agency. Article II takes a critical gender perspective and analyzes how two girls struggled towards recognition in the playworld. It also illuminates the role of imagination in developing a sense of agency. Article III examines how the open-ended and improvisational nature of the playworld interaction provided experiences and a sense of ‘shared agency’ for the students and teachers in the class. Article IV turns the focus on the teachers and analyzes how their role actions in the playworld helped the children to enact agency. It also discusses the challenges that the teachers faced in this work and asks what makes the playworld activity sustainable in the class. The summary part provides a critical literature review on the concept of agency and argues that the inherently contradictory nature of the phenomenon of agency has not been sufficiently theorized. The summary part also locates the playworld intervention in a historical frame by discussing the changing conceptions of adulthood and childhood in the West. By focusing on the changing role of play and art in both adults’ and children’s contemporary lives, the thesis opens up an important but often neglected perspective on the problem of promoting student agency in education. The results illustrate how engaging in a collectively imagined and dramatized pretend play space together with the children enabled the teachers to momentarily put aside their “knower” positions in the classroom. The fictive roles and the narrative plot helped them to create a necessary incompleteness and open-endedness in the activity that stimulated the children’s initiatives. This meant that the children too could momentarily step out of their traditional classroom positions as pupils and initiate action to further the collective play. Engaging in this kind of unconventional activity and taking up and enacting agency was, however, very challenging for the participating children and teachers. It often contradicted the need to sustain control and order in the classroom. The study concludes that play- and drama-based pedagogies offer a unique but undeveloped potential for developing educational spaces that help teachers and children deal with the often contradictory requirements of schooling.
Influence of Solvent on Photoinduced Electron-Transfer Reaction: Time-Resolved Resonance Raman Study
Resumo:
Time-resolved resonance Raman spectroscopy (TR3) has been used to study the effect of solvent polarity on the mechanism and nature of intermediates formed in photoinduced electron-transfer reaction between triplet flouranil ((FL)-F-3) and tetramethylbenzene (TMB). Comparison of the TR3 spectra in polar, nonpolar, and medium polar media suggests that formation of radical anion due to electron-transfer reaction between (FL)-F-3 and TMB is favored in more polar solvents, whereas ketyl radical formation is more favored in less polar media. Compared to ketyl radical, the extent of radical anion formation is negligible in nonpolar solvents. Therefore, it is inferred that in nonpolar media ketyl radical is mainly generated by hydrogen-transfer reaction in the encounter complex between (FL)-F-3 and TMB. In solvents of medium polarity, the ion-pair decay leads to the formation of both ketyl radical and ketyl radical formed from the encounter between triplet state and the donor. Thus, competition between the formation of ketyl radical and ion pair is influenced by the solvent polarity. The nature of the ion pair in different solvent polarity has been investigated from the changes observed in the vibrational frequency of (fluoranil) FL part of the complex.
Resumo:
The anomeric effect in S---C---S and O---C---S systems was studied by using closed-shell Hartree-Fock theory. A comparison of the STO-3G level with the 4–31G and 6–31G* levels was performed for the O---C---O system, and the STO-3G level found adequate for study of the anomeric effect. Optimization of bond lengths and angles was conducted at the STO-3G level and limited studies were made at the 4–31G level. The nature of the torsional potential curves is compared for the O---C---O, O---C---S, and S---C---S systems. The possible reasons for the decreased anomeric effect in sulfur systems are discussed.