791 resultados para Representations of algebras


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Background Recent research provides evidence for specific disturbance in feeding and growth in children of mothers with eating disorders. Aim To investigate the impact of maternal eating disorders during the post-natal year on the internal world of children, as expressed in children's representations of self and their mother in pretend mealtime play at 5 years of age. Methods Children of mothers with eating disorders (n = 33) and a comparison group (n = 24) were videotaped enacting a family mealtime in pretend play. Specific classes of children's play representations were coded blind to group membership. Univariate analyses compared the groups on representations of mother and self. Logistic regression explored factors predicting pretend play representations. Results Positive representations of the mother expressed as feeding, eating or body shape themes were more frequent in the index group. There were no other significant group differences in representations. In a logistic regression analysis, current maternal eating psychopathology was the principal predictor of these positive maternal representations. Marital criticism was associated with negative representations of the mother. Conclusions These findings suggest that maternal eating disorders may influence the development of a child's internal world, such that they are more preoccupied with maternal eating concerns. However, more extensive research on larger samples is required to replicate these preliminary findings.

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We examined the impact on adolescent socioemotional functioning of maternal postnatal depression (PND) and attachment style. We also investigated the role of earlier aspects of the child's development-attachment in infancy, and 5-year representations of family relationships. Ninety-one mother-child pairs, recruited in the postnatal period, were followed tip at 13 years. Adolescents were interviewed about their friendships, and their level of emotional sensitivity and maturity were rated. Emotional sensitivity was heightened in girls whose mothers experienced PND; notably, its occurrence was also linked to insecure attachment in infancy and raised awareness of emotional components of family relationships at 5 years. High emotional sensitivity was also associated with adolescent depressed mood. Raised social maturity was predicted by a secure maternal attachment style and, for girls, by exposure to maternal PND. Precursors of adolescent social maturity were evident in the narrative coherence of 5-year family representations. Higher social maturity in the friendship interview was also associated with overall good adjustment.

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This paper describes the impact of changing the current imposed ozone climatology upon the tropical Quasi-Biennial Oscillation (QBO) in a high top climate configuration of the Met Office U.K. general circulation model. The aim is to help distinguish between QBO changes in chemistry climate models that result from temperature-ozone feedbacks and those that might be forced by differences in climatology between previously fixed and newly interactive ozone distributions. Different representations of zonal mean ozone climatology under present-day conditions are taken to represent the level of change expected between acceptable model realizations of the global ozone distribution and thus indicate whether more detailed investigation of such climatology issues might be required when assessing ozone feedbacks. Tropical stratospheric ozone concentrations are enhanced relative to the control climatology between 20–30 km, reduced from 30–40 km and enhanced above, impacting the model profile of clear-sky radiative heating, in particular warming the tropical stratosphere between 15–35 km. The outcome is consistent with a localized equilibrium response in the tropical stratosphere that generates increased upwelling between 100 and 4 hPa, sufficient to account for a 12 month increase of modeled mean QBO period. This response has implications for analysis of the tropical circulation in models with interactive ozone chemistry because it highlights the possibility that plausible changes in the ozone climatology could have a sizable impact upon the tropical upwelling and QBO period that ought to be distinguished from other dynamical responses such as ozone-temperature feedbacks.

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Background: Children’s representations of mothers in doll-play are associated with child adjustment. Despite the importance of fathers for children’s adjustment, especially in the context of maternal psychopathology, few studies have considered children’s representations of their fathers. Method: We examined the portrayal of fathers by 5-year-old children of depressed (N = 55) and non-depressed (N = 39) mothers in a doll-play procedure concerning family experience. Results: Children gave equal prominence in their play to mothers and fathers. Representations of fathers were unrelated to maternal mood, but were associated with parental conflict. Representations of child care for the father that was unreciprocated predicted poor child adjustment in school, but only in children exposed to maternal postnatal depression. Conclusions: It may be clinically useful to consider children’s distinctive representations of their mother and father; but the concept of parentification in relation to risk and resilience effects requires refinement.

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Using a literature review, we argue that new models of peatland development are needed. Many existing models do not account for potentially important ecohydrological feedbacks, and/or ignore spatial structure and heterogeneity. Existing models, including those that simulate a near total loss of the northern peatland carbon store under a warming climate, may produce misleading results because they rely upon oversimplified representations of ecological and hydrological processes. In this, the first of a pair of papers, we present the conceptual framework for a model of peatland development, DigiBog, which considers peatlands as complex adaptive systems. DigiBog accounts for the interactions between the processes which govern litter production and peat decay, peat soil hydraulic properties, and peatland water-table behaviour, in a novel and genuinely ecohydrological manner. DigiBog consists of a number of interacting submodels, each representing a different aspect of peatland ecohydrology. Here we present in detail the mathematical and computational basis, as well as the implementation and testing, of the hydrological submodel. Remaining submodels are described and analysed in the accompanying paper. Tests of the hydrological submodel against analytical solutions for simple aquifers were highly successful: the greatest deviation between DigiBog and the analytical solutions was 2·83%. We also applied the hydrological submodel to irregularly shaped aquifers with heterogeneous hydraulic properties—situations for which no analytical solutions exist—and found the model's outputs to be plausible.

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This essay explores the ways in which the performance of Jewish identity (in the sense both of representing Jewish characters and of writing about those characters’ conscious and unconscious renditions of their Jewishness) is a particular concern (in both senses of the word) for Lorrie Moore. Tracing Moore's representations of Jewishness over the course of her career, from the early story “The Jewish Hunter” through to her most recent novel, A Gate at the Stairs, I argue that it is characterized by (borrowing a phrase from Moore herself) “performance anxiety,” an anxiety that manifests itself in awkward comedy and that can be read both in biographical terms and as an oblique commentary on, or reworking of, the passing narrative, which I call “anti-passing.” Just as passing narratives complicate conventional ethno-racial definitions so Moore's anti-passing narratives, by representing Jews who represent themselves as other to themselves, as well as to WASP America, destabilize the category of Jewishness and, by implication, deconstruct the very notion of ethnic categorization.

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The play Epic Sea Battle at Night was originally staged in 1967, to commemorate two of China’s People’s Liberation Army’s military triumphs over the Taiwanese navy two years previously. Produced at the height of the Chinese Cultural Revolution, the play is an example of the exploitation of the arts as an ideological instrument, celebrating military heroism and political conviction. Stills from the play were included in, China Pictorial 11, an English language propaganda pamphlet that was distributed to Western Imperialists in order to educate them in Maoist policy. Today, these images are clear representations of ideology. More than forty years after the Cultural Revolution, the ideology under which we live, neo-liberal late-capitalism, deliberately shirks from such blatant displays of propaganda. We have supposedly the freedom to believe whatever we like in a post-ideological age, and yet core beliefs about meritocracy, individualism and competitiveness frequently go unchallenged. By juxtaposing the visual language of ideology with the text of the capitalist manifesto, the re-enactment of a scene from Epic Sea Battle at Night harnesses the aesthetics of the past so as to allow us to reconsider the alleged neutrality of the present. The design of the stage, the positioning of the actors, costumes and props of the current production closely resembled those documented in China Pictorial 11, yet the actors’ monologues belong to a completely different context. No less heroic and utopian in tone than the speech given by the political instructor of gunboat 874 in the original play, the capitalist manifesto was an attempt to give a concrete language to the shapeless ideology of the present, and to force the invisible currents that govern life today, in China as in the West, to the surface. Neither a lecture on neo-liberal economics, nor a theatrical performance of a narrative, the piece appropriated the format of the propaganda play to re-evaluate the relationship between art and politics now.

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This paper analyses tendencies in debates about cultural representations of terrorism to assume that artists make critical interventions, while the mass media circulates stereotypes. Some recent feminist analyses of female terrorist acts have re-instituted essentialist arguments in which violence and terrorism is described as inherently masculine, while women are by nature pacifist, so that femininity is the antithesis of militarism. More progressive analyses mostly tend to expose the circulation of stereotypes and their gender bias, in order to protest the misrepresentation of women in violence. These analyses do not construct alternative accounts. Through an analysis of two works by artists Hito Steyerl and Sharon Hayes, the paper argues that some of the moves to re-image the question of women, violence and agency have already been made in contemporary art practices. Through analysing legacies of terrorism and feminism, it becomes possible to rethink the question of agency, militancy and the nature of political art. The paper appears in an edited interdiscplinary collection arising from a conference at Universität der Bundeswehr in Munich. It relates to wider projects involving collaborations with Birkbeck and Edinburgh on representations of terrorism and on violence and contemporary art.

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Software representations of scenes, i.e. the modelling of objects in space, are used in many application domains. Current modelling and scene description standards focus on visualisation dimensions, and are intrinsically limited by their dependence upon their semantic interpretation and contextual application by humans. In this paper we propose the need for an open, extensible and semantically rich modelling language, which facilitates a machine-readable semantic structure. We critically review existing standards and techniques, and highlight a need for a semantically focussed scene description language. Based on this defined need we propose a preliminary solution, based on hypergraph theory, and reflect on application domains.

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In the first part of this article, we introduced a new urban surface scheme, the Met Office – Reading Urban Surface Exchange Scheme (MORUSES), into the Met Office Unified Model (MetUM) and compared its impact on the surface fluxes with respect to the current urban scheme. In this second part, we aim to analyze further the reasons behind the differences. This analysis is conducted by a comparison of the performance of the two schemes against observations and against a third model, the Single Column Reading Urban model (SCRUM). The key differences between the three models lie in how each model incorporates the heat stored in the urban fabric and how the surface-energy balance is coupled to the underlying substrate. The comparison of the models with observations from Mexico City reveals that the performance of MORUSES is improved if roof insulation is included by minimizing the roof thickness. A comparison of MORUSES and SCRUM reveals that, once insulation is included within MORUSES, these two models perform equally well against the observations overall, but that there are differences in the details of the simulations at the roof and canyon level. These differences are attributed to the different representations of the heat-storage term, specifically differences in the dominant frequencies captured by the urban canopy and substrate, between the models. These results strongly suggest a need for an urban model intercomparison exercise. Copyright © 2010 Royal Meteorological Society and Crown Copyright

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The Egyptians mesmerized the ancient Greeks for scores of years. The Greek literature and art of the classical period are especially thick with representations of Egypt and Egyptians. Yet despite numerous firsthand contacts with Egypt, Greek writers constructed their own Egypt, one that differed in significant ways from actual Egyptian history, society, and culture. Informed by recent work on orientalism and colonialism, this book unravels the significance of these misrepresentations of Egypt in the Greek cultural imagination in the fifth and fourth centuries B.C.E. Looking in particular at issues of identity, otherness, and cultural anxiety, Phiroze Vasunia shows how Greek authors constructed an image of Egypt that reflected their own attitudes and prejudices about Greece itself. He focuses his discussion on Aeschylus Suppliants; Book 2 of Herodotus; Euripides' Helen; Plato's Phaedrus, Timaeus, and Critias; and Isocrates' Busiris. Reconstructing the history of the bias that informed these writings, Vasunia shows that Egypt in these works was shaped in relation to Greek institutions, values, and ideas on such subjects as gender and sexuality, death, writing, and political and ethnic identity. This study traces the tendentiousness of Greek representations by introducing comparative Egyptian material, thus interrogating the Greek texts and authors from a cross-cultural perspective. A final chapter also considers the invasion of Egypt by Alexander the Great and shows how he exploited and revised the discursive tradition in his conquest of the country. Firmly and knowledgeably rooted in classical studies and the ancient sources, this study takes a broad look at the issue of cross-cultural exchange in antiquity by framing it within the perspective of contemporary cultural studies. In addition, this provocative and original work shows how Greek writers made possible literary Europe's most persistent and adaptable obsession: the barbarian.

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Models of root system growth emerged in the early 1970s, and were based on mathematical representations of root length distribution in soil. The last decade has seen the development of more complex architectural models and the use of computer-intensive approaches to study developmental and environmental processes in greater detail. There is a pressing need for predictive technologies that can integrate root system knowledge, scaling from molecular to ensembles of plants. This paper makes the case for more widespread use of simpler models of root systems based on continuous descriptions of their structure. A new theoretical framework is presented that describes the dynamics of root density distributions as a function of individual root developmental parameters such as rates of lateral root initiation, elongation, mortality, and gravitropsm. The simulations resulting from such equations can be performed most efficiently in discretized domains that deform as a result of growth, and that can be used to model the growth of many interacting root systems. The modelling principles described help to bridge the gap between continuum and architectural approaches, and enhance our understanding of the spatial development of root systems. Our simulations suggest that root systems develop in travelling wave patterns of meristems, revealing order in otherwise spatially complex and heterogeneous systems. Such knowledge should assist physiologists and geneticists to appreciate how meristem dynamics contribute to the pattern of growth and functioning of root systems in the field.

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Although tactile representations of the two body sides are initially segregated into opposite hemispheres of the brain, behavioural interactions between body sides exist and can be revealed under conditions of tactile double simultaneous stimulation (DSS) at the hands. Here we examined to what extent vision can affect body side segregation in touch. To this aim, we changed hand-related visual input while participants performed a go/no-go task to detect a tactile stimulus delivered to one target finger (e.g., right index), stimulated alone or with a concurrent non-target finger either on the same hand (e.g., right middle finger) or on the other hand (e.g., left index finger = homologous; left middle finger = non-homologous). Across experiments, the two hands were visible or occluded from view (Experiment 1), images of the two hands were either merged using a morphing technique (Experiment 2), or were shown in a compatible vs incompatible position with respect to the actual posture (Experiment 3). Overall, the results showed reliable interference effects of DSS, as compared to target-only stimulation. This interference varied as a function of which non-target finger was stimulated, and emerged both within and between hands. These results imply that the competition between tactile events is not clearly segregated across body sides. Crucially, non-informative vision of the hand affected overall tactile performance only when a visual/proprioceptive conflict was present, while neither congruent nor morphed hand vision affected tactile DSS interference. This suggests that DSS operates at a tactile processing stage in which interactions between body sides can occur regardless of the available visual input from the body.

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We present the results of simulations carried out with the Met Office Unified Model at 12km, 4km and 1.5km resolution for a large region centred on West Africa using several different representations of the convection processes. These span the range of resolutions from much coarser than the size of the convection processes to the cloud-system resolving and thus encompass the intermediate "grey-zone". The diurnal cycle in the extent of convective regions in the models is tested against observations from the Geostationary Earth Radiation Budget instrument on Meteosat-8. By this measure, the two best-performing simulations are a 12km model without convective parametrization, using Smagorinsky style sub-grid scale mixing in all three dimensions and a 1.5km simulations with two-dimensional Smagorinsky mixing. Of these, the 12km model produces a better match to the magnitude of the total cloud fraction but the 1.5km results in better timing for its peak value. The results suggest that the previously-reported improvement in the representation of the diurnal cycle of convective organisation in the 4km model compared to the standard 12km configuration is principally a result of the convection scheme employed rather than the improved resolution per se. The details of and implications for high-resolution model simulations are discussed.

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The chapter focuses on attempts to change and improve the subjects of the colonial regime in what was the British Protectorate of Tanganyika, contemporary Tanzania. The colonial project in Africa was surrounded by technology, ideology, and representations of modernity based on the application of instrumental rationality. Through the example of colonial practices to control sleeping sickness, it examines how local forms of knowledge and livelihoods were negated and counter-tendencies people generated, offering explanations for the predicament of the human condition consequent upon the colonial experience.