860 resultados para collective excitations in multilayers


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Thesis (Ph.D.)--University of Washington, 2016-06

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'Social capital' refers to the relationships of trust, communication, and cooperation that facilitate collective action in a community. It is particularly relevant to soil conservation in developing countries, which requires collective efforts to raise awareness of soil degradation, provide effective training in soil conservation practices, and implement soil conservation measures on individual farms. The Landcare Program in the Southern Philippines promotes simple conservation practices in upland environments through establishing and supporting community landcare groups and municipal landcare associations, thus augmenting the social capital of farmers in these locations. An evaluation of the Landcare Program in Barangay Ned, South Cotabato, based on a survey of 313 farm households and case studies of nine landcare groups, shows that, despite extreme isolation and difficult working conditions, farmers responded by rapidly forming landcare groups and a landcare association, and adopting contour barriers on their maize farms. They utilized the bonding social capital inhering in their local communities to build stocks of bridging social capital, linking them to information, training and resources from outside their immediate locality. A logistic regression model of the factors affecting adoption of contour barriers shows that farmers who had undergone the practical, farmer-based training provided by the Landcare Program, and who were members of a landcare group, were significantly more likely to adopt conservation measures. These results confirm the value of investing in social capital to promote soil conservation. Copyright (c) 2005 John Wiley & Sons, Ltd.

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This article examines how the Ukrainian state has used, and continues to use, history to forge collective identities in Ukraine. It assesses how history textbooks are utilised by the state as ‘tools’ to introduce schoolchildren to key historical episodes around which a modern Ukrainian national identity can be shaped. Attempts to ‘historicise’ Ukrainian national identity must answer fundamental questions such as: Who are we? Where have we come from? Where are we going? Who are we not? The final question is vital in understanding ‘who we are’ in comparison to the ‘other’. Thus, emphasis is placed on how the Ukrainian state is attempting to form an all-encompassing Ukrainian identity by distancing itself from Russia. The article argues that while a ‘national’ history is being espoused, a ‘regional politics of the textbook’ is subtly being allowed by the state to develop. This stands at odds with state attempts to create one universal, all-encompassing Ukrainian history.

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The fundamental problem faced by noninvasive neuroimaging techniques such as EEG/MEG1 is to elucidate functionally important aspects of the microscopic neuronal network dynamics from macroscopic aggregate measurements. Due to the mixing of the activities of large neuronal populations in the observed macroscopic aggregate, recovering the underlying network that generates the signal in the absence of any additional information represents a considerable challenge. Recent MEG studies have shown that macroscopic measurements contain sufficient information to allow the differentiation between patterns of activity, which are likely to represent different stimulus-specific collective modes in the underlying network (Hadjipapas, A., Adjamian, P., Swettenham, J.B., Holliday, I.E., Barnes, G.R., 2007. Stimuli of varying spatial scale induce gamma activity with distinct temporal characteristics in human visual cortex. NeuroImage 35, 518–530). The next question arising in this context is whether aspects of collective network activity can be recovered from a macroscopic aggregate signal. We propose that this issue is most appropriately addressed if MEG/EEG signals are to be viewed as macroscopic aggregates arising from networks of coupled systems as opposed to aggregates across a mass of largely independent neural systems. We show that collective modes arising in a network of simulated coupled systems can be indeed recovered from the macroscopic aggregate. Moreover, we show that nonlinear state space methods yield a good approximation of the number of effective degrees of freedom in the network. Importantly, information about hidden variables, which do not directly contribute to the aggregate signal, can also be recovered. Finally, this theoretical framework can be applied to experimental MEG/EEG data in the future, enabling the inference of state dependent changes in the degree of local synchrony in the underlying network.

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The following research project investigated the mediating effects of individual trust in the relationships between eight leadership dimensions and follower motivation and efficacy. The research comprised of a total of three studies of which two are individual level analyses investigating the above relationship for individual followers, while the final study established the relationship between the eight dimensions and collective efficacy and group cohesion. A new measure of trust — collective vertical trust — was developed and tested and formed the mediator for the final study. The findings showed that leadership is indeed mediated through trust on both individual and collective level in the majority of relationships. In addition it was shown that individual and collective vertical trust are significantly related. Finally, the final study showed an absence of a significant relationship between trust on both the individual and collective level and organizational performance. The findings contributed to existing research in various ways: 1) the mediating effect of individual trust was established for eight separate leadership dimensions; 2) the studies established that while the indirect effects of leadership on follower motivation are similar amongst all age groups and levels of work experience, more work experienced individuals draw their beliefs in their abilities (i.e., self-efficacy) from alternative sources than leadership or trust in the leader; 3) a new measure of collective trust —collective vertical trust was established; 4) the mediating effect of collective trust was shown to be crucial in leadership effects on collective efficacy and group cohesion; and finally 5) a leadership measure initially designed for executive leaders was refined and tested for non-executive leaders.

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Background. The secondary structure of folded RNA sequences is a good model to map phenotype onto genotype, as represented by the RNA sequence. Computational studies of the evolution of ensembles of RNA molecules towards target secondary structures yield valuable clues to the mechanisms behind adaptation of complex populations. The relationship between the space of sequences and structures, the organization of RNA ensembles at mutation-selection equilibrium, the time of adaptation as a function of the population parameters, the presence of collective effects in quasispecies, or the optimal mutation rates to promote adaptation all are issues that can be explored within this framework. Results. We investigate the effect of microscopic mutations on the phenotype of RNA molecules during their in silico evolution and adaptation. We calculate the distribution of the effects of mutations on fitness, the relative fractions of beneficial and deleterious mutations and the corresponding selection coefficients for populations evolving under different mutation rates. Three different situations are explored: the mutation-selection equilibrium (optimized population) in three different fitness landscapes, the dynamics during adaptation towards a goal structure (adapting population), and the behavior under periodic population bottlenecks (perturbed population). Conclusions. The ratio between the number of beneficial and deleterious mutations experienced by a population of RNA sequences increases with the value of the mutation rate µ at which evolution proceeds. In contrast, the selective value of mutations remains almost constant, independent of µ, indicating that adaptation occurs through an increase in the amount of beneficial mutations, with little variations in the average effect they have on fitness. Statistical analyses of the distribution of fitness effects reveal that small effects, either beneficial or deleterious, are well described by a Pareto distribution. These results are robust under changes in the fitness landscape, remarkably when, in addition to selecting a target secondary structure, specific subsequences or low-energy folds are required. A population perturbed by bottlenecks behaves similarly to an adapting population, struggling to return to the optimized state. Whether it can survive in the long run or whether it goes extinct depends critically on the length of the time interval between bottlenecks. © 2010 Stich et al; licensee BioMed Central Ltd.

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Concha Meléndez opened up a venue for the discussion of a Latin American identity in works of literature when she implied that the great Latin American novel would gestate in the cities, the space where the typical Latin American would achieve an ideal state of consciousness and intellectual capabilities. ^ Her point of view mirrored nineteenth-century debate on a Latin American identity. Similar to her viewpoint, intellectuals of this period viewed the cities and their inhabitants of European extraction, as the ideal spaces and people on which an identity could be defined. However, the present state of urban and rural areas in Latin America demonstrates that there is no such clear-cut division of city and countryside or of their inhabitants. The dynamics of movement, from rural to urban areas, of people of diverse ethnic, and socioeconomic backgrounds, make it difficult to uphold descriptors of space, race, or culture, as sole descriptors of an identity. ^ A study of five twentieth-century novels from North and South America, La muerte de Artemio Cruz (1962), Hasta no verte Jesús mío (1969), Los ríos profundos (1981), La casa de los espíritus (1982), and Los años con Laura Díaz (1999) reveal that the dynamism of movement, between countryside, and cities of peoples of distinct races and social backgrounds, hamper the definition of a collective identity in specific spaces. As characters move, they are constantly reconfiguring their identities and creating tensions and conflicts that intensify social, racial and economic divisions in society. This makes it difficult to ascribe permanent identity descriptors, much less define a collective identity. ^ However, as writers of fiction address the malaise in Latin American societies, they have unearthed descriptors such as history, economy, land, and movement that advance a collective definition of self in these societies. Additionally, female characters have been granted a new identity. The overwhelming evidence in this study points to ‘land’ as the prime factor in the identity dilemma and suggests that a definition will not be possible until the vast landless populace is granted a space they can call home. Only then, perhaps, will Meléndez novel surface. ^

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Background Cell-to-cell communication (quorum sensing (QS)) co-ordinates bacterial behaviour at a population level. Consequently the behaviour of a natural multi-species community is likely to depend at least in part on co-existing QS and quorum quenching (QQ) activities. Here we sought to discover novelN-acylhomoserine lactone (AHL)-dependent QS and QQ strains by investigating a bacterial community associated with the rhizosphere of ginger (Zingiber officinale) growing in the Malaysian rainforest. Results By using a basal growth medium containing N-(3-oxohexanoyl)homoserine lactone (3-oxo-C6-HSL) as the sole source of carbon and nitrogen, the ginger rhizosphere associated bacteria were enriched for strains with AHL-degrading capabilities. Three isolates belonging to the generaAcinetobacter (GG2), Burkholderia (GG4) and Klebsiella (Se14) were identified and selected for further study. Strains GG2 and Se14 exhibited the broadest spectrum of AHL-degrading activities via lactonolysis while GG4 reduced 3-oxo-AHLs to the corresponding 3-hydroxy compounds. In GG2 and GG4, QQ was found to co-exist with AHL-dependent QS and GG2 was shown to inactivate both self-generated and exogenously supplied AHLs. GG2, GG4 and Se14 were each able to attenuate virulence factor production in both human and plant pathogens. Conclusions Collectively our data show that ginger rhizosphere bacteria which make and degrade a wide range of AHLs are likely to play a collective role in determining the QS-dependent phenotype of a polymicrobial community.

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This dissertation analyzes six twenty-first century novels that reflect Spain's current intellectual trends on the Spanish Civil War, Francoism and the transition to a democratic system. These novels deal with the complex correlation between memory and amnesia caused by the traumatic events of the Civil War. Despite the abundance of literature on this topic, these writers insist on the need for the recovery of historical and collective memory in order to halt the negative historical revisionism of recent years. Beginning with the death of Francisco Franco, this work focuses on the historical-theoretical framework that leads to the development of this mnemonic narrative and outlines the politics of memory effectuated during the transitional period, a lieu de mémoire frequently revisited and examined by new generations of writers. The novels analyzed also call for the retelling of history from the perspective of everyday people and address the need to pay overdue homage to victims of the post-war era.^ This work concludes that, while the texts may be considered settings for posthumous tributes, they could likewise advocate for a national reconciliation. Thus, as this narrative reveals, by focusing more on the need for a work on memory than on political and ideological polarizations, the memory of restitution does not interfere with the memory of reconciliation. The writers in question are nonetheless aware that reconciliation cannot be based on a spurious amnesia. The first step, therefore, towards reconciliation is to achieve a legitimate dialogue with regard to the traumatic past, and literary works may offer a tenable path. ^

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Trade unions in India find themselves excluded from the political process and marginalized in collective bargaining in the post economic reforms period since 1991. Influential policy analysts and academics alike have called upon Indian trade unions to engage in social partnership with employers as a route to regain influence and protect workers’ interests. Using survey and interview data from two large national trade union federations in Maharashtra India, this article examines whether social partnership is a viable option for Indian trade unions as an industrial relations approach. Findings indicate that despite a supportive labour regulatory framework which in theory should facilitate cooperative industrial relations, the ground realities of workplace employment relations coupled with state indifference and judicial interventions weakens labour’s prospects for meaningful social partnership.

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This practice-led research looks at the ways in which the colonial archive, and the colonial photographic archive in particular, can be reconstructed to produce new critical histories. The research argues for the potential of the moving image as a tool for re-staging colonial archives, as a means of generating responsible ways of looking at, and of engaging with our troubled collective pasts. In my practice I mix the photographic archive of the Anglo-Iranian Oil Company(which became BP) with my family’s photographs from Iran, and with the documentation and narrativization of my encounter with both of these sets of materials, within the moving image. Through this process I address questions about the nature of the photographic archive and the search for historical meaning within it; the question of the researcher’s position within the archive and within the history she produces; and I investigate the affective power of colonial photographs within film and the experience of untimeliness which they produce. While addressing problems associated with the failure of photographic archives to offer access to any stable, transparent meaning, I show how engaging with slippages of meaning can produce other kinds of historical knowledge. But I also argue that attending to the impression of the ‘real’ produced by the colonial photograph as it appears within film, makes the past felt in the present tense, in ways that draw attention to the responsibility of being an onlooker in a situation of injustice. In addition I show how registering the place and time of the researcher within the new filmic archive in motion produces an effective means of imaginative time travel and a lively experience of history.

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This paper is a constructivist attempt to understand a global political space where states as actors (the traditional domain of international relations theory and international law) are joined by international organizations, firms, NGOs, and others. Today we know that many supposedly private or international orders (meaning sources of order other than the central institutions of the territorial state) are engaged in the regulation of large domains of collective life in a world where the sources of power are multiple, sovereignties are overlapping, and anarchy is meaningless. The paper begins with an attempt, discussed in the first section, to sort out what the rule of law might mean in the context of the WTO, where we soon see that it can only be understood by also considering the meaning of Administrative Law. Much of the debate about rule of law depends on positivist and centralist theories of “law,” whose inadequacy for my purposes leads, in the second section, to a discussion of legal pluralism and implicit law in legal theory. These approaches offer an alternative theoretical framework that respects the role of the state while not seeing it as the only source of normativity. The third section looks directly at WTO law and dispute settlement. I tr y to show that the sources and interpretations of law in the WTO and the trading system cannot be reduced to the Dispute Settlement Body. I conclude in the fourth section with some suggestions on how a WTO rule of law could be understood as democratic.

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The article examines developments in the marketisation and privatisation of the English National Health Service, primarily since 1997. It explores the use of competition and contracting out in ancillary services and the levering into public services of private finance for capital developments through the Private Finance Initiative. A substantial part of the article examines the repeated restructuring of the health service as a market in clinical services, initially as an internal market but subsequently as a market increasing opened up to private sector involvement. Some of the implications of market processes for NHS staff and for increased privatisation are discussed. The article examines one episode of popular resistance to these developments, namely the movement of opposition to the 2011 health and social care legislative proposals. The article concludes with a discussion of the implications of these system reforms for the founding principles of the NHS and the sustainability of the service.

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The concept of ontological security has a remarkable echo in the current sociology to describe emotional status of men of late modernity. However, the concept created by Giddens in the eighties has been little used in empirical research covering various sources of risk or uncertainty. In this paper, a scale for ontological security is proposed. To do this, we start from the results of a research focused on the relationship between risk, uncertainty and vulnerability in the context of the economic crisis in Spain. These results were produced through nine focus groups and a telephone survey with standardized questionnaire applied to a national sample of 2,408 individuals over 18 years. This work is divided into three main sections. In the fi rst, a scale has been built from the results of the application of different items present in the questionnaire used. The second part explores the relationships of the scale obtained with the variables further approximate the emotional dimensions of individuals. The third part observes the variables that contribute to changes in the scale: These variables show the structural feature of the ontological security.