Effets du vieillissement sur les index électrophysiologiques de l’évaluation des relations spatiales en mémoire de travail visuelle

Le processus de vieillissement humain est un processus complexe qui varie grandement d’une personne à l’autre. Malgré l’ampleur des recherches faites sur le sujet, il reste encore beaucoup à explorer et à comprendre. Cette thèse propose trois expériences qui nous permettent d’améliorer notre compréhension des changements qui s’opèrent dans la mémoire de travail visuelle et l’attention visuospatiale avec la prise en âge. La première expérience propose d’examiner les changements dans les capacités de mémoire de travail visuelle entre des jeunes adultes, des adultes âgés sains et des personnes atteintes de trouble cognitif léger (TCL). De plus, grâce à un suivi fait avec les personnes ayant un TCL, nous avons pu examiner si des différences existaient au niveau comportemental entre les âgés qui ont déclinés vers un type de démence et ceux dont l’état est resté stable. Plusieurs techniques peuvent être utilisées pour étudier les effets du vieillissement sur le cerveau. Les tests neuropsychologiques et les tâches comportementales présentées dans la première expérience en sont un exemple. La neuroimagerie peut aussi s’avérer particulièrement utile. En effet, certaines mesures électrophysiologiques, aussi appelées potentiels reliés aux évènements (PRE), sont associées à des fonctions cognitives précises. Ces composantes nous permettent de suivre ces processus et d’observer les modulations causées par les caractéristiques des stimuli ou l’âge par exemple. C’est le cas de la N2pc (négativité 2 postérieure controlatérale) et de la SPCN (sustained posterior contralateral negativity), des composantes électrophysiologiques liées respectivement à l’attention visuospatiale et la mémoire de travail visuelle. On connait bien ces deux composantes ainsi que les facteurs qui les modulent, or elles sont peu utilisées pour les changements qui occurrent dans l’attention et la mémoire de travail visuelle dans le cadre du processus de vieillissement. Les deuxième et troisième expériences proposent d’utiliser une tâche de recherche visuelle (nombre d’items de couleur et identification d’une relation spatiale entre deux items de couleur) afin d’explorer les changements observables sur ces composantes électrophysiologiques. La deuxième expérience examine l’efficacité d’un paradigme à présentations multiples (‘multiple frame’) afin de mesurer la N2pc et la SPCN chez de jeunes adultes. La troisième expérience a pour but d’examiner les effets du vieillissement normal sur l’amplitude et la latence de la N2pc et la SPCN en utilisant le même type de tâche de recherche visuelle.

Structure–activity relations (SARs) for gas-phase reactions of NO3, OH and O3 with alkenes: an update

We present updated structure-activity relations (SARs) for the prediction of rate coefficients for gas-phase reactions with alkenes of the major atmospheric oxidants NO3, OH and O-3. Such SARs provide one way of incorporating essential information about reactivity into atmospheric models. Rate coefficients obtained from correlations relating the logarithms of the rate coefficients to the energies of the highest occupied molecular orbitals (HOMOs) of the alkenes were used to refine the SARs. SARs have an advantage for the user over the direct application of the correlations in that knowledge of the structure of the alkene of interest is sufficient to estimate rate coefficients, and no quantum-mechanical calculations need to be performed. A comparison of the values predicted by the SARs with experimental data where they exist allowed us to assess the reliability of our method.

Gas-phase rate coefficients for the reactions of O(3P), S(3P), Se(3P), and Te(3P) with alkenes: application of perturbation frontier molecular orbital theory, correlations, and structure-activity relations (SARs)

The kinetics of the reactions of the atoms O(P-3), S(P-3), Se(P-3), and Te((3)p) with a series of alkenes are examined for correlations relating the logarithms of the rate coefficients to the energies of the highest occupied molecular orbitals (HOMOs) of the alkenes. These correlations may be employed to predict rate coefficients from the calculated HOMO energy of any other alkene of interest. The rate coefficients obtained from the correlations were used to formulate structure-activity relations (SARs) for reactions of O((3)p), S(P-3), Se (P-3), and Te((3)p) with alkenes. A comparison of the values predicted by both the correlations and the SARs with experimental data where they exist allowed us to assess the reliability of our method. We demonstrate the applicability of perturbation frontier molecular orbital theory to gas-phase reactions of these atoms with alkenes. The correlations are apparently not applicable to reactions of C(P-3), Si(P-3), N(S-4), and Al(P-2) atoms with alkenes, a conclusion that could be explained in terms of a different mechanism for reaction of these atoms.

Effect of soil waterlogging on below-ground biomass allometric relations in Norway spruce

An increasing importance is assigned to the estimation and verification of carbon stocks in forests. Forestry practice has several long-established and reliable methods for the assessment of aboveground biomass; however we still miss accurate predictors of belowground biomass. A major windthrow event exposing the coarse root systems of Norway spruce trees allowed us to assess the effects of contrasting soil stone and water content on belowground allocation. Increasing stone content decreases root/shoot ratio, while soil waterlogging leads to an increase in this ratio. We constructed allometric relationships for belowground biomass prediction and were able to show that only soil waterlogging significantly impacts model parameters. We showed that diameter at breast height is a reliable predictor of belowground biomass and, once site-specific parameters have been developed, it is possible to accurately estimate belowground biomass in Norway spruce.

Institutional legacies and capabilities: work practices and employment relations in Portugal and Mozambique

This is a study of institutional change and continuity, comparing the trajectories followed by Mozambique and its formal colonial power Portugal in HRM, based on two surveys of firm level practices. The colonial power sought to extend the institutions of the metropole in the closing years of its rule, and despite all the adjustments and shocks that have accompanied Mozambique’s post-independence years, the country continues to retain institutional features and associated practices from the past. This suggests that there is a post-colonial impact on human resource management. The implications for HRM theory are that ambitious attempts at institutional substitution may have less dramatic effects than is commonly assumed. Indeed, we encountered remarkable similarities between the two countries in HRM practices, implying that features of supposedly fluid or less mature institutional frameworks (whether in Africa or the Mediterranean world) may be sustained for protracted periods of time, pressures to reform notwithstanding. This highlights the complexities of continuities which transcend formal rules; as post-colonial theories alert us, informal conventions and embedded discourse may result in the persistence of informal power and subordination, despite political and legal changes.

The exclusionary policies of 'us and them' in the IPA and psychoanalytic institutes

This article will explore the issues of otherness in the IPA and also consider the local institute level using the example of the British Psychoanalytic Society. According to the IPA it is 'The world's primary psychoanalytic accrediting and regulatory body, with 10,500 members in over forty-five countries. The IPA works in partnership with its Component Organizations to train, support and network psychoanalysts, developing clinical, educational and research programmes'. It is well-known that the history of psychoanalysis is replete with organizational schisms and primary issues of 'inclusion-exclusion'. Who is a real psychoanalyst? "That are the necessary acceptable professional 'standards'? 'While standards' should be derived from knowledge, they are often derived from power and are often really a mask for power-plays. The others' have included those from both outside and within the psychoanalytic movement. Outsiders include medicine and the universities, psychotherapists, other psychoanalysts and other disciplines. Deviationists ,.vithin the IPA include other schools vvithin the'broad church' of psychoanalysis or even just those who don't fit with the proclivities of those in power sometimes rationalized into issues of standards

Misuse of the term 'stakeholder' in public relations

This article queries the relatively recent adoption of the term 'stakeholder', borrowed from the UK political and the US business management spheres, in public relations academic writing. The article concludes that these spheres use the term in a normative or ideological manner that has worrying implications. The term frames people as having a pre-existing relationship with the governments or business organisations which name them as such. This process of incorporation prejudges and potentially obscures the real relations of groups of people vis-à-vis governments and business organisations which they may wish to have nothing to do with. An argument is mounted for the defence of the term 'publics'. It is pointed out that a key originator of stakeholder theory opposes the notion of 'publics' as closer to a notion of an uncontrolled audience. The article argues that the notion of 'publics' is more fitting than the notion of 'stakeholders' if public relations is about acknowledging this uncontrollability, and to do with advising organisations about their positioning in the democratic milieu. On the other hand, the notion 'stakeholders' may be the right one if public relations is simply aimed at immediately shaping people's behaviour, irrespective of longer term and wider political implications.

Theories of international relations

This collection of essays demonstrates the continuing importance of the work of Michael Polanyi for the understanding, not only of the great events of the 20th century, but also of the problems that face us in the 21st century. Polanyi moved liberalism away from a negative, sceptical and rationalist basis towards an acceptance of trust, tradition and faith in transcendent values. His conception of the free society is not one merely of doing as one pleases nor vacuously 'open', but one of individual and communal self-dedication to those values and ideals.These essays, authored by a distinguished international and interdisciplinary panel of invited contributors, examine Polanyi's specific insights in the theory of knowledge, the nature and source of social order and the philosophy of economics and science and draw relevant comparisons between Polanyi and related thinkers such as Popper, Hayek and Mises. This book shows the sources of Polanyi's ideas and his distinctive contribution to philosophy generally, to social and political thought and to economics.

Logistics: Our buildings are always particular to places, access, materials, skills and technologies. How do these limits provide us with architectural opportunities?

Presents a discussion on the relations between architecture and spirituality during the 2005 conference of the Royal Architecture Institute of Australia. Reason behind difficulty encountered by architects to associate architecture and spirituality; Inspiration of Jae Cha of architectural firm Light for designing the Bolivian church; View of Kevin O'Brien of Merrima Design on Aboriginal buildings.

Indo-US strategic ties on the upswing

Strategic ties based on converging national interests shared perceptions of the evolving Asia-Pacific security environment are strengthening between India and USA. The sanctions imposed in response to IndiaEs 1998 nuclear tests were relaxed and military-to-military links were stored with the joining of India in US-led war on terror.

Public relations, sophistry and the rhetoric of democracy

The intention of this paper is to explain the activities of public relations in terms of rhetorical theory and the history of sophistry. There is a burgeoning field of study in the US which is incorporating much cultural and communication theory into both historical and contemporary perspectives on these two ancient arts. Consequently, an examination of the purposive communication activities of public relations offers an opportunity to involve semiotics as a central concept for analysing the creation and maintenance of democratic thought and institutions. This paper highlights Peircean semiotics in this respect and suggests the relevance of Peirce's notion of the 'Pragmatic Maxim' and his use of the concept of 'habit' in terms of how public relations might be said to 'cast' the quality of the democracy which we experience.

Public relations and the rhetoric of civil society

The intention of this paper is to build on a book by Anne Surma (2005). It takes some of Surma’s ideas probably beyond what was originally intended in order to suggest their logical conclusions for the practice of public relations. Surma argues that writing and reading of every type enables or otherwise facilitates or restricts imagination. Further, this shaping or inflection of the imagination leads to the shaping or the inflection of the type of ‘ethic’ which we are able to hold in our heads about the world which surrounds us. If this is the case then public relations writing, which has the very raison d’etre of influencing thought, must lend itself to important analysis in this regard. This paper presumes the reader has a basic understanding of Charles Saunders Peirce’s notion of semiotics.

Mining characteristic relations bind to RNA secondary structures

The identification of RNA secondary structures has been among the most exciting recent developments in biology and medical science. It has been recognized that there is an abundance of functional structures with frameshifting, regulation of translation, and splicing functions. However, the inherent signal for secondary structures is weak and generally not straightforward due to complex interleaving substrings. This makes it difficult to explore their potential functions from various structure data. Our approach, based on a collection of predicted RNA secondary structures, allows us to efficiently capture interesting characteristic relations in RNA and bring out the top-ranked rules for specified association groups. Our results not only point to a number of interesting associations and include a brief biological interpretation to them. It assists biologists in sorting out the most significant characteristic structure patterns and predicting structurefunction relationships in RNA.

Pakistan-China bilateral relations 2001-2011 : a deepening but cautious partnership

Last year (2011) marked the sixtieth anniversary of the establishment of diplomatic relations between Pakistan and China. The bilateral relationship has deepened significantly since 1951, with both countries benefiting from this relationship. However, Pakistan would like to deepen it even further, while China is more pragmatic and cautious. There are irritants, notably the killing of Chinese citizens, the presence of Uighur militants in Pakistan and their different interests in Afghanistan, which could put some stress on the relationship. While the relationship will continue to grow, China is not about to displace the US as Pakistan’s major economic and military aid provider.

Public relations, activism, and social change: speaking up

Why are some voices louder in public debates than others? And why can’t all voices be equally heard? This book draws significant new meaning to the inter-relationships of public relations and social change through a number of activist case studies, and rebuilds knowledge around alternative communicative practices that are ethical, sustainable, and effective. Demetrious offers a powerful critical description of the dominant model of public relations used in the twentieth century, showing that ‘PR’ was arrogant, unethical and politically offensive in ways that have severely weakened democratic process and its public standing and professional credibility. The book argues that change within the field of public relations is imminent and urgent—for us all. As the effects of climate change intensify, and are magnified by high carbon dioxide emitting industries, vigorous public debate is vital in the exploration of new ideas and action and if alternative futures are to be imagined. In these conditions, articulate and persistent publics will appear in the form of grassroots activists, asking contentious questions about risks and tabling them for public discussion in bold, inventive, and effective ways. Yet the entrenched power relations in and through public relations in contemporary industrialized society provide no certainty these voices will be heard. Following this path, Demetrious theorises an alternative set of social relations to those used in the twentieth century: public communication. Constructed from communicative practices of grassroots activists and synthesis of diverse theoretical positions, public communication is a principled approach that avoids the deep contradictions and flawed coherences of essentialist public relations and instead represents an important ethical reorientation in the communicative fields. Lastly, she brings original new perspectives to understand current and emergent developments in activism and public relations brought about through the proliferation of Internet and digital cultures.