15 resultados para Non-line-of-sight

em Aston University Research Archive


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The elaboration of curli fimbriae by Escherichia coli is associated with the development of a lacy colony morphology when grown on colonisation factor antigen agar at 25 degrees C. Avian colisepticaemia E. coli isolates screened for curliation by this culture technique showed lacy and smooth colonial morphologies and the genetic basis of the non-curliated smooth colonial phenotype was analysed. Two smooth E. coli O78:K80 isolates possessed about 40 copies of the IS1 element within their respective genomes of which one copy insertionally inactivated the csgB gene, the nucleator gene for curli fibril formation. One of these two isolates also possessed a defective rpoS gene which is a known regulator of curli expression. In the day-old chick model, both smooth isolates were as invasive as a known virulent O78:K80 isolate as determined by extent of liver and spleen colonisation post oral inoculation but were less persistent in terms of caecal colonisation.

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The slope of the two-interval, forced-choice psychometric function (e.g. the Weibull parameter, ß) provides valuable information about the relationship between contrast sensitivity and signal strength. However, little is known about how or whether ß varies with stimulus parameters such as spatiotemporal frequency and stimulus size and shape. A second unresolved issue concerns the best way to estimate the slope of the psychometric function. For example, if an observer is non-stationary (e.g. their threshold drifts between experimental sessions), ß will be underestimated if curve fitting is performed after collapsing the data across experimental sessions. We measured psychometric functions for 2 experienced observers for 14 different spatiotemporal configurations of pulsed or flickering grating patches and bars on each of 8 days. We found ß ˜ 3 to be fairly constant across almost all conditions, consistent with a fixed nonlinear contrast transducer and/or a constant level of intrinsic stimulus uncertainty (e.g. a square law transducer and a low level of intrinsic uncertainty). Our analysis showed that estimating a single ß from results averaged over several experimental sessions was slightly more accurate than averaging multiple estimates from several experimental sessions. However, the small levels of non-stationarity (SD ˜ 0.8 dB) meant that the difference between the estimates was, in practice, negligible.

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This paper investigates whether the non-normality typically observed in daily stock-market returns could arise because of the joint existence of breaks and GARCH effects. It proposes a data-driven procedure to credibly identify the number and timing of breaks and applies it on the benchmark stock-market indices of 27 OECD countries. The findings suggest that a substantial element of the observed deviations from normality might indeed be due to the co-existence of breaks and GARCH effects. However, the presence of structural changes is found to be the primary reason for the non-normality and not the GARCH effects. Also, there is still some remaining excess kurtosis that is unlikely to be linked to the specification of the conditional volatility or the presence of breaks. Finally, an interesting sideline result implies that GARCH models have limited capacity in forecasting stock-market volatility.

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We set out to distinguish level 1 (VPT-1) and level 2 (VPT-2) perspective taking with respect to the embodied nature of the underlying processes as well as to investigate their dependence or independence of response modality (motor vs. verbal). While VPT-1 reflects understanding of what lies within someone else’s line of sight, VPT-2 involves mentally adopting someone else’s spatial point of view. Perspective taking is a high-level conscious and deliberate mental transformation that is crucially placed at the convergence of perception, mental imagery, communication, and even theory of mind in the case of VPT-2. The differences between VPT-1 and VPT-2 mark a qualitative boundary between humans and apes, with the latter being capable of VPT-1 but not of VPT-2. However, our recent data showed that VPT-2 is best conceptualized as the deliberate simulation or emulation of a movement, thus underpinning its embodied origins. In the work presented here we compared VPT-2 to VPT-1 and found that VPT-1 is not at all, or very differently embodied. In a second experiment we replicated the qualitatively different patterns for VPT-1 and VPT-2 with verbal responses that employed spatial prepositions. We conclude that VPT-1 is the cognitive process that subserves verbal localizations using “in front” and “behind,” while VPT-2 subserves “left” and “right” from a perspective other than the egocentric. We further conclude that both processes are grounded and situated, but only VPT-2 is embodied in the form of a deliberate movement simulation that increases in mental effort with distance and incongruent proprioception. The differences in cognitive effort predict differences in the use of the associated prepositions. Our findings, therefore, shed light on the situated, grounded and embodied basis of spatial localizations and on the psychology of their use.

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Being able to judge another person's visuo-spatial perspective is an essential social skill, hence we investigated the generalizability of the involved mechanisms across cultures and genders. Developmental, cross-species, and our own previous research suggest that two different forms of perspective taking can be distinguished, which are subserved by two distinct mechanisms. The simpler form relies on inferring another's line-of-sight, whereas the more complex form depends on embodied transformation into the other's orientation in form of a simulated body rotation. Our current results suggest that, in principle, the same basic mechanisms are employed by males and females in both, East-Asian (EA; Chinese) and Western culture. However, we also confirmed the hypothesis that Westerners show an egocentric bias, whereas EAs reveal an other-oriented bias. Furthermore, Westerners were slower overall than EAs and showed stronger gender differences in speed and depth of embodied processing. Our findings substantiate differences and communalities in social cognition mechanisms across genders and two cultures and suggest that cultural evolution or transmission should take gender as a modulating variable into account.

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The logic of ‘time’ in modern capitalist society appears to be a fixed concept. Time dictates human activity with a regularity, which as long ago as 1944, George Woodcock referred to as The Tyranny of the Clock. Seventy years on, Hartmut Rosa suggests humans no longer maintain speed to achieve something new, but simply to preserve the status quo, in a ‘social acceleration’ that is lethal to democracy. Political engagement takes time we no longer have, as we rush between our virtual spaces and ‘non-places’ of higher education. I suggest it’s time to confront the conspirators that, in partnership with the clock, accelerate our social engagements with technology in the context of learning. Through Critical Discourse Analysis (CDA) I reveal an alarming situation if we don’t. With reference to Bauman’s Liquid Modernity, I observe a ‘lightness’ in policy texts where humans have been ‘liquified’ Separating people from their own labour with technology in policy maintains the flow of speed a neoliberal economy demands. I suggest a new ‘solidity’ of human presence is required as we write about networked learning. ‘Writing ourselves back in’ requires a commitment to ‘be there’ in policy and provide arguments that decelerate the tyranny of time. I am though ever-mindful that social acceleration is also of our own making, and there is every possibility that we actually enjoy it.

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If love is a social as well as a personal reality, it could be fruitful to compare Von Hildebrand’s understanding of love and desire with that of cultural anthropologist René Girard. Girard depicts love and desire as a triangular process which arises from imitation, rather than the result of auto-generative affection. In this sense, Girardian theory would seem to convict Von Hildebrand of what is called the romantic lie wherein desire is thought to arise through the mutual appreciation of two subjects. However, in The Nature of Love Von Hildebrand shows his awareness of the possibility that love can be awakened by imitation. Moreover, the lack of a sufficient reason in Girardian theory for avoiding violence can be answered by turning to Von Hildebrand’s appreciation of the ontological basis for desire.

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Our work investigating managerial practices in UK manufacturing organisations has shown that people management practices play an important role in promoting innovation. Having developed an instrument to analyse innovation (defined by West and Farr in 1990 as “the intentional introduction and application in a job, work team or organisation of ideas, processes, products or procedures which are new, and designed to benefit the job, the work team or the organisation”), we were able to give each of the 30 organisations in our sample a score of between one and seven to capture innovation in a range of domains. This instrument took into account the magnitude of the innovation in terms of the number of people involved in its implementation, and how new and different it was. We found that much innovation involves relatively minor, ongoing improvements, rather than major change. To achieve sustained innovation, organisations must be able to draw upon the skills and knowledge of employees at all levels of the business. So which HRM practices are most likely to promote a positive learning environment? We developed a scale to take into account three facets of HRM that shape the learning environment and predict the extent to which individuals can gain the skills to promote innovation. First, organisations should have a vision statement capturing their approach to learning and development and communicating to staff the importance that they attach to these processes. Second, they must implement and endorse mentoring schemes. Last, they should consider offering staff the opportunity to have regular career development meetings. Where a positive learning climate exists, organisations tend to be more innovative. The results also show that organisations that make explicit the link between appraisal and remuneration perform relatively less well in innovation terms than those whose appraisal systems have no relationship with pay. Many have argued (for example, Lawler,1995) that pay-for-performance schemes provide a “line of sight” between performance and reward, thereby enabling individuals to make appropriate decisions about where best to direct the effort. Our findings do not imply that performance-related pay is ill advised in all circumstances, but we suggest that organisations should exercise caution before introducing such schemes. People are central to innovation, and this study suggests that high innovation can be achieved when people are empowered to make changes at local levels. HRM has an important, perhaps crucial, role to play in creating an environment that enables people to develop the skills and confidence necessary to affect change. Key points: Organisational innovation is an important determinant of competitive performance and advancement, enabling organisations to anticipate and respond to the challenges of globalisation. HRM has an important, perhaps crucial, role to play in promoting organisational innovation – to the extent that it creates a positive environment for learning and removes barriers that may inhibit creative performance (for example, linking appraisal to remuneration).

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Adopting another’s visual perspective is exceedingly common and may underlie successful social interaction and empathizing with others. The individual differences responsible for success in perspective-taking, however, remain relatively undiscovered. We assessed whether gender and autistic personality traits in normal college student adults predict the ability to adopt another’s visual perspective. In a task differentially recruiting VPT-1 which involves following another’s line of sight, and VPT-2 which involves determining how another may perceive an object differently given their unique perspective (VPT-2), we found effects of both gender and autistic personality traits. Specifically, we demonstrate slowed VPT-2 but not VPT-1 performance in males and females with relatively high ASD-characteristic personality traits; this effect, however was markedly stronger in males than females. Results contribute to knowledge regarding ASD-related personality traits in the general population and the individual differences modulating perspective-taking abilities.

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What is the role of pragmatics in the evolution of grammatical paradigms? It is to maintain marked candidates that may come to be the default expression. This perspective is validated by the Jespersen cycle, where the standard expression of sentential negation is renewed as pragmatically marked negatives achieve default status. How status changes are effected, however, remains to be documented. This is what is achieved in this paper that looks at the evolution of preverbal negative non in Old and Middle French. The negative, which categorically marks pragmatic activation (Dryer 1996) with finite verbs in Old French, loses this value when used with non-finite verbs in Middle French. This process is accompanied by competing semantic reanalyses of the distribution of infinitives negated in this way, and by the co-occurrence with a greater lexical variety of verbs. The absence of pragmatic contribution should lead the marker to take on the role of default, which is already fulfilled by a well-established ne ... pas, pushing non to decline. Hard empirical evidence is thus provided that validates the assumed role of pragmatics in the Jespersen cycle, supporting the general view of pragmatics as supporting alternative candidates that may or may not achieve default status in the evolution of a grammatical paradigm.

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Purpose – This paper attempts to seek answers to four questions. Two of these questions have been borrowed (but adapted) from the work of Defee et al.: RQ1. To what extent is theory used in purchasing and supply chain management (P&SCM) research? RQ2. What are the prevalent theories to be found in P&SCM research? Following on from these questions an additional question is posed: RQ3. Are theory-based papers more highly cited than papers with no theoretical foundation? Finally, drawing on the work of Harland et al., the authors have added a fourth question: RQ4. To what extent does P&SCM meet the tests of coherence, breadth and depth, and quality necessary to make it a scientific discipline? Design/methodology/approach – A systematic literature review was conducted in accordance with the model outlined by Tranfield et al. for three journals within the field of “purchasing and supply chain management”. In total 1,113 articles were reviewed. In addition a citation analysis was completed covering 806 articles in total. Findings – The headline features from the results suggest that nearly a decade-and-a-half on from its development, the field still lacks coherence. There is the absence of theory in much of the work and although theory-based articles achieved on average a higher number of citations than non-theoretical papers, there is no obvious contender as an emergent paradigm for the discipline. Furthermore, it is evident that P&SCM does not meet Fabian's test necessary to make it a scientific discipline and is still some way from being a normal science. Research limitations/implications – This study would have benefited from the analysis of further journals, however the analysis of 1,113 articles from three leading journals in the field of P&SCM was deemed sufficient in scope. In addition, a further significant line of enquiry to follow is the rigour vs relevance debate. Practical implications – This article is of interest to both an academic and practitioner audience as it highlights the use theories in P&SCM. Furthermore, this article raises a number of important questions. Should research in this area draw more heavily on theory and if so which theories are appropriate? Social implications – The broader social implications relate to the discussion of how a scientific discipline develops and builds on the work of Fabian and Amundson. Originality/value – The data set for this study is significant and builds on a number of previous literature reviews. This review is both greater in scope than previous reviews and is broader in its subject focus. In addition, the citation analysis (not previously conducted in any of the reviews) and statistical test highlights that theory-based articles are more highly cited than non-theoretically based papers. This could indicate that researchers are attempting to build on one another's work.

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The present research represents a coherent approach to understanding the root causes of ethnic group differences in ability test performance. Two studies were conducted, each of which was designed to address a key knowledge gap in the ethnic bias literature. In Study 1, both the LR Method of Differential Item Functioning (DIF) detection and Mixture Latent Variable Modelling were used to investigate the degree to which Differential Test Functioning (DTF) could explain ethnic group test performance differences in a large, previously unpublished dataset. Though mean test score differences were observed between a number of ethnic groups, neither technique was able to identify ethnic DTF. This calls into question the practical application of DTF to understanding these group differences. Study 2 investigated whether a number of non-cognitive factors might explain ethnic group test performance differences on a variety of ability tests. Two factors – test familiarity and trait optimism – were able to explain a large proportion of ethnic group test score differences. Furthermore, test familiarity was found to mediate the relationship between socio-economic factors – particularly participant educational level and familial social status – and test performance, suggesting that test familiarity develops over time through the mechanism of exposure to ability testing in other contexts. These findings represent a substantial contribution to the field’s understanding of two key issues surrounding ethnic test performance differences. The author calls for a new line of research into these performance facilitating and debilitating factors, before recommendations are offered for practitioners to ensure fairer deployment of ability testing in high-stakes selection processes.