960 resultados para Gibbs phenomenon
Resumo:
The field of epigenetics looks at changes in the chromosomal structure that affect gene expression without altering DNA sequence. A large-scale modelling project to better understand these mechanisms is gaining momentum. Early advances in genetics led to the all-genetic paradigm: phenotype (an organism's characteristics/behaviour) is determined by genotype (its genetic make-up). This was later amended and expressed by the well-known formula P = G + E, encompassing the notion that the visible characteristics of a living organism (the phenotype, P) is a combination of hereditary genetic factors (the genotype, G) and environmental factors (E). However, this method fails to explain why in diseases such as schizophrenia we still observe differences between identical twins. Furthermore, the identification of environmental factors (such as smoking and air quality for lung cancer) is relatively rare. The formula also fails to explain cell differentiation from a single fertilized cell. In the wake of early work by Waddington, more recent results have emphasized that the expression of the genotype can be altered without any change in the DNA sequence. This phenomenon has been tagged as epigenetics. To form the chromosome, DNA strands roll over nucleosomes, which are a cluster of nine proteins (histones), as detailed in Figure 1. Epigenetic mechanisms involve inherited alterations in these two structures, eg through attachment of a functional group to the amino acids (methyl, acetyl and phosphate). These 'stable alterations' arise during development and cell proliferation and persist through cell division. While information within the genetic material is not changed, instructions for its assembly and interpretation may be. Modelling this new paradigm, P = G + E + EpiG, is the object of our study.
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Dried plant food materials are one of the major contributors to the global food industry. Widening the fundamental understanding on different mechanisms of food material alterations during drying assists the development of novel dried food products and processing techniques. In this regard, case hardening is an important phenomenon, commonly observed during the drying processes of plant food materials, which significantly influences the product quality and process performance. In this work, a recent meshfree-based numerical model of the authors is further improved and used to simulate the influence of case hardening on shrinkage characteristics of plant tissues during drying. In order to model fluid and wall mechanisms in each cell, Smoothed Particle Hydrodynamics (SPH) and the Discrete Element Method (DEM) are used. The model is fundamentally more capable of simulating large deformation of multiphase materials, when compared with conventional grid-based modelling techniques such as Finite Element Methods (FEM) or Finite Difference Methods (FDM). Case hardening is implemented by maintaining distinct moisture levels in the different cell layers of a given tissue. In order to compare and investigate different factors influencing tissue deformations under case hardening, four different plant tissue varieties (apple, potato, carrot and grape) are studied. The simulation results indicate that the inner cells of any given tissue undergo limited shrinkage and cell wall wrinkling compared to the case hardened outer cell layers of the tissues. When comparing unique deformation characteristics of the different tissues, irrespective of the normalised moisture content, the cell size, cell fluid turgor pressure and cell wall characteristics influence the tissue response to case hardening.
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People typically evaluate their in-groups more favorably than out-groups and themselves more favorably than others. Research on infrahumanization also suggests a preferential attribution of the “human essence” to in-groups, independent of in-group favoritism. The authors propose a corresponding phenomenon in interpersonal comparisons: People attribute greater humanness to themselves than to others, independent of self-enhancement. Study 1 and a pilot study demonstrated 2 distinct understandings of humanness—traits representing human nature and those that are uniquely human—and showed that only the former traits are understood as inhering essences. In Study 2, participants rated themselves higher than their peers on human nature traits but not on uniquely human traits, independent of selfenhancement. Study 3 replicated this “self-humanization” effect and indicated that it is partially mediated by attribution of greater depth to self versus others. Study 4 replicated the effect experimentally. Thus, people perceive themselves to be more essentially human than others.
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What is ‘transmedia’? This chapter attempts to understand what this phenomenon is from a transhistorical perspective. The transhistorical nature of media combinations is interrogated in light of media specificity and in relation to the key phenomena of Intermedia. Transmedia is argued to be a transhistorical urge towards unifying that which has been artificially estranged.
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Discourses on in/security are often concerned with structures and meta-narratives of the state and other institutions; however, such attention misses the complexities of the everyday consequences of insecurity. In Colombia’s protracted conflict, children are disproportionately affected yet rarely consulted, rendering it difficult to account for their experiences in meaningful ways. This article draws on fieldwork conducted with conflict-affected children in an informal barrio community on the periphery of Colombia’s capital, Bogotá, to explore how children articulate experiences of insecurity. It examines how stereotypes of violence and delinquency reinforce insecurity; how multiple violences impact young people’s lives; and how children themselves conceive of responses to these negative experiences. These discussions are underpinned by a feminist commitment of attention to the margins and engage with those for whom insecurity is a daily phenomenon. The effects of deeply embedded insecurity, violence, and fear for young people in Colombia require a more nuanced theoretical engagement with notions of insecurity, as well as the complexities of connections and dissonances within everyday life.
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In this paper, Bree Hadley discusses The Ex/centric Fixations Project, a practice-led research project which explores the inadequacy of language as a technology for expressing human experiences of difference, discrimination or marginalisation within mainstream cultures. The project asks questions about the way experience, memory and the public discourses available to express them are bound together, about the silences, failures and falsehoods embedded in any effort to convey human experience via public discourses, and about how these failures might form the basis of a performative writing method. It has, to date, focused on developing a method that expresses experience through improvised, intertextual and discontinous collages of language drawn from a variety of public discourses. Aesthetically, this method works with what Hans Theis Lehmann (Postdramatic Theatre p. 17) calls a “textual variant” of the postdramatic “in which language appears not as the speech of characters – if there are still definable characters at all – but as an autonomous theatricality” (Ibid. 18). It is defined by what Lehmann, following Julia Kristeva, calls a “polylogue”, which presents experience as a conflicted, discontinuous and circular phenomenon, akin to a musical fugue, to break away from “an order centred on one logos” (Ibid. 32). The texts function simultaneously as a series of parts, and as wholes, interwoven voices seeming almost to connect, almost to respond to each other, and almost to tell – or challenging each other’s telling – of a story. In this paper, Hadley offers a performative demonstration, together with descriptions of the way spectators respond, including the way their playful, polyvocal texture impacts on engagement, and the way the presence or non-presence of performing bodies to which the experiences depicted can be attached impacts on engagement. She suggests that the improvised, intertextual and experimental enactments of self embodied in the texts encourage spectators to engage at an emotional level, and make-meaning based primarily on memories they recall in the moment, and thus has the potential to counter the risk that people may read depictions of experiences radically different from their own in reductive, essentialised ways.
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Pranks, hoaxes and practical jokes are co-creative cultural performance practices that appear across times, contexts and cultures. These practices include everyday play amongst families, friends and coworkers, entertainment programs such as Prank Patrol, Punked or Scare Tactics, and aesthetic and activist pranks perpetrated by situationist artists, guerrilla artists, and, most recently, culture ‘jammers’ or ‘hackers’ intent on turning capitalist systems back on themselves. Although it can, in common usage, describe almost any show off behaviour, a prank in the strictest definition of the term is a performance that deploys a very specific set of strategies. It is an act of trickery, mischief, or deceit, that must be taken as real, and momentarily cause real fear, anger or worry for an unwitting spectator-become-performer, who is meant to play along until the trick is revealed and their response can be represented back to the prankster, other spectators, or society as a whole, either for the sake of entertainment or for the sake of commentary on a cultural phenomenon. A prank, in this sense, deliberately blurs the boundaries between daily and dramatic performance. It creates a moment of uncertainty, in which both the prankster’s ability to be creative, clever, or culturally astute, and the prankee’s ability to play along, discern the trick, discern the point of the trick, and, in the end, be duped, be a good sport, or even play/pay the prankster back, are both put to the test. In this paper, I consider a number of pranking traditions popular where I am in Australia, from the community-building pranks of footballers, bucks parties and ‘drop bear’ tales told to tourists, to the more controversial pranks of radio shock jocks, activists and artists. I use performance, spectatorship and ethical theory to examine the engagement between prankster, pranked spectator, and other spectators, in this most distinctive sort of community-driven performance practice, and the way it builds and breaks status, social and other sorts of relationships within and between specific communities.
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This investigation for the removal of agricultural pollutants, imazaquin and atrazine was conducted using montmorillonite (MMT) exchanged with organic cations through ion exchange. The study found that the adsorption of the herbicides was affected by the degree of organic cation saturations, the size of organic cations and the different natures of the herbicides. The modified clays intercalated with the larger surfactant molecules at the higher concentrations tended to enhance the adsorption of imazaquin and atrazine. In particular, the organoclays were highly efficient for the removal of imazaquin while the adsorption of atrazine was minimal due to the different hydrophobicities. Both imazaquin and atrazine were influenced by the changes of pH. The amphoteric imazaquin exists as an anion at the pH 5–7 and the anionic imazaquin was protonated to a neutral and further a cationic form when the pH is lower. The weak base, atrazine was also protonated at lower pH values. The anionic imazaquin had a strong affinity to the organoclays on the external surface as well as in the interlayer space of the MMT through electrostatic and hydrophobic interactions. In this study, the electrostatic interaction can be the primary mechanism involved during the adsorption process. This study also investigated a comparative adsorption for the imazaquin and atrazine and the lower adsorption of atrazine was enhanced and this phenomenon was due to the synergetic effect. This work highlights a potential mechanism for the removal of specific persistence herbicides from the environment.
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This report, written for the Australian Film Commission (now Screen Australia) is the first major study of the development and role of studio complexes in the spread of film production around the world. The report is divided in to five chapters. First, it examines policy-making around studios, including government support for new facilities around the world. Second, it situates the phenomenon of the contemporary studio complex within the international production ecology. Third, it provides examples of the three types of studio complex: production precinct; cinema city; and media city. Fourth, it describes the networks of production that sustain studios. And fifth it explores the place of the studio in the relationship between 'local' and international production.
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Purpose The purpose of this research is to explore the idea of the participatory library in higher education settings. This research aims to address the question, what is a participatory university library? Design/methodology/approach Grounded theory approach was adopted. In-depth individual interviews were conducted with two diverse groups of participants including ten library staff members and six library users. Data collection and analysis were carried out simultaneously and complied with Straussian grounded theory principles and techniques. Findings Three core categories representing the participatory library were found including “community”, “empowerment”, and “experience”. Each category was thoroughly delineated via sub-categories, properties, and dimensions that all together create a foundation for the participatory library. A participatory library model was also developed together with an explanation of model building blocks that provide a deeper understanding of the participatory library phenomenon. Research limitations The research focuses on a specific library system, i.e., academic libraries. Therefore, the research results may not be very applicable to public, special, and school library contexts. Originality/value This is the first empirical study developing a participatory library model. It provides librarians, library managers, researchers, library students, and the library community with a holistic picture of the contemporary library.
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Enhancement of bone mineral acquisition during growth may be a useful preventive strategy against osteoporosis. The aim of this study was to explore the lean mass, strength, and bone mineral response to a 10-month, high-impact, strength-building exercise program in 71 premenarcheal girls, aged 9–10 years. Lean body mass, total body (TB), lumbar spine (LS), proximal femur (PF), and femoral neck (FN) bone mineral were measured using the Hologic QDR 2000+ bone densitometer. Strength was assessed using a grip dynamometer and the Cybex isokinetic dynamometer (Cybex II). At baseline, no significant difference in body composition, pubertal development, calcium intake, physical activity, strength, or bone mineral existed between groups. At completion, there were again no differences in height, total body mass, pubertal development, calcium intake, or external physical activity. In contrast, the exercise group gained significantly more lean mass, less body fat content, greater shoulder, knee and grip strength, and greater TB, LS, PF, and FN BMD (exercise: TB 3.5%, LS 4.8%, PF 4.5%, and FN 12.0%) compared with the controls (controls: TB 1.2%, LS 1.2%, PF 1.3%, and FN 1.7%). TB bone mineral content (BMC), LS BMC, PF BMC, FN BMC, LS bone mineral apparent density (BMAD), and FN bone area also increased at a significantly greater rate in the exercise group compared with the controls. In multiple regression analysis, change in lean mass was the primary determinant of TB, FN, PF, and LS BMD accrual. Although a large proportion of bone mineral accrual in the premenarcheal skeleton was related to growth, an osteogenic effect was associated with exercise. These results suggest that high-impact, strength building exercise is beneficial for premenarcheal strength, lean mass gains, and bone mineral acquisition.
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In this chapter we introduce and explore the notion of “intentionally enriched awareness”. Intentional enrichment refers to the process of actively engaging users in the awareness process by enabling them to express intentions. We initially look at the phenomenon if sharing intentional information in related collaborative systems. We then explore the concept of intentional enrichment through designing and evaluating the AnyBiff system which allows users to freely create, share and use a variety of biff applications. Biffs are simple representation of pre-defined activities. Users can select biffs to indicate that they are engaged in an activity. We summarise the results of a trial which allowed us to gain insights into the potential of the AnyBiff prototype and the underlying biff concept to implement intentionally enriched awareness. Our findings show that intentional disclosure mechanisms in the form of biffs were successfully used in a variety of contexts. Users actively engaged in the design of a large variety of biffs and explored many different uses of the concept. The study revealed a whole host of issues with regard to intentionally enriched awareness which give valuable insight into the conception and design of future applications in this area.
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Platinum chemotherapeutic agents such as cisplatin are currently used in the treatment of various malignancies such as lung cancer. However, their efficacy is significantly hindered by the development of resistance during treatment. While a number of factors have been reported that contribute to the onset of this resistance phenotype, alterations in the DNA repair capacity of damaged cells is now recognised as an important factor in mediating this phenomenon. The mode of action of cisplatin has been linked to its ability to crosslink purine bases on the DNA, thereby interfering with DNA repair mechanisms and inducing DNA damage. Following DNA damage, cells respond by activating a DNA-damage response that either leads to repair of the lesion by the cell thereby promoting resistance to the drug, or cell death via activation of the apoptotic response. Therefore, DNA repair is a vital target to improving cancer therapy and reduce the resistance of tumour cells to DNA damaging agents currently used in the treatment of cancer patients. To date, despite the numerous findings that differential expression of components of the various DNA repair pathways correlate with response to cisplatin, translation of such findings in the clinical setting are still warranted. The identification of alterations in specific proteins and pathways that contribute to these unique DNA repair pathways in cisplatin resistant cancer cells may potentially lead to a renewed interest in the development of rational novel therapies for cisplatin resistant cancers, in particular, lung cancer.
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Scope: Coffee is among the most frequently consumed beverages. Its consumption is inversely associated to the incidence of diseases related to reactive oxygen species; the phenomenon may be due to its antioxidant properties. Our primary objective was to investigate the impact of consumption of a coffee containing high levels of chlorogenic acids on the oxidation of proteins, DNA and membrane lipids; additionally, other redox biomarkers were monitored in an intervention trial. Methods and results: The treatment group (n=36) consumed instant coffee co-extracted from green and roasted beans, whereas the control consumed water (800 mL/P/day, 5 days). A global statistical analysis of four main biomarkers selected as primary outcomes showed that the overall changes are significant. 8-Isoprostaglandin F2α in urine declined by 15.3%, 3-nitrotyrosine was decreased by 16.1%, DNA migration due to oxidized purines and pyrimidines was (not significantly) reduced in lymphocytes by 12.5 and 14.1%. Other markers such as the total antioxidant capacity were moderately increased; e.g. LDL and malondialdehyde were shifted towards a non-significant reduction. Conclusion: The oxidation of DNA, lipids and proteins associated with the incidence of various diseases and the protection against their oxidative damage may be indicative for beneficial health effects of coffee.