70 resultados para Lack of memory property
Resumo:
BACKGROUND AND PURPOSE:
Amyloid-ß (Aß) aggregation into synaptotoxic, prefibrillar oligomers is a major pathogenic event underlying the neuropathology of Alzheimer's disease (AD). The pharmacological and neuroprotective properties of a novel Aß aggregation inhibitor, SEN1269, were investigated on aggregation and cell viability and in test systems relevant to synaptic function and memory, using both synthetic Aß(1-42) and cell-derived Aß oligomers.
EXPERIMENTAL APPROACH:
Surface plasmon resonance studies measured binding of SEN1269 to Aß(1-42) . Thioflavin-T fluorescence and MTT assays were used to measure its ability to block Aß(1-42) -induced aggregation and reduction in cell viability. In vitro and in vivo long-term potentiation (LTP) experiments measured the effect of SEN1269 on deficits induced by synthetic Aß(1-42) and cell-derived Aß oligomers. Following i.c.v. administration of the latter, a complex (alternating-lever cyclic ratio) schedule of operant responding measured effects on memory in freely moving rats.
KEY RESULTS:
SEN1269 demonstrated direct binding to monomeric Aß(1-42) , produced a concentration-related blockade of Aß(1-42) aggregation and protected neuronal cell lines exposed to Aß(1-42) . In vitro, SEN1269 alleviated deficits in hippocampal LTP induced by Aß(1-42) and cell-derived Aß oligomers. In vivo, SEN1269 reduced the deficits in LTP and memory induced by i.c.v. administration of cell-derived Aß oligomers.
CONCLUSIONS AND IMPLICATIONS:
SEN1269 protected cells exposed to Aß(1-42) , displayed central activity with respect to reducing Aß-induced neurotoxicity and was neuroprotective in electrophysiological and behavioural models of memory relevant to Aß-induced neurodegeneration. It represents a promising lead for designing inhibitors of Aß-mediated synaptic toxicity as potential neuroprotective agents for treating AD.
Resumo:
The eye and the brain are prototypical tissues manifesting immune privilege (IP) in which immune responses to foreign antigens, particularly alloantigens are suppressed, and even completely inhibited. Explanations for this phenomenon are numerous and mostly reflect our evolving understanding of the molecular and cellular processes underpinning immunological responses generally. IP is now viewed as a property of many tissues and the level of expression of IP varies not only with the tissue but with the nature of the foreign antigen and changes in the limited conditions under which privilege can operate as a mechanism of immunological tolerance. As a result, IP functions normally as a homeostatic mechanism preserving normal function in tissues, particularly those with highly specialized function and limited capacity for renewal such as the eye and brain. However, IP is relatively easily bypassed in the face of a sufficiently strong immunological response, and the privileged tissues may be at greater risk of collateral damage because its natural defenses are more easily breached than in a fully immunocompetent tissue which rapidly rejects foreign antigen and restores integrity. This two-edged sword cuts its swathe through the eye: under most circumstances, IP mechanisms such as blood-ocular barriers, intraocular immune modulators, induction of T regulatory cells, lack of lymphatics, and other properties maintain tissue integrity; however, when these are breached, various degrees of tissue damage occur from severe tissue destruction in retinal viral infections and other forms of uveoretinal inflammation, to less severe inflammatory responses in conditions such as macular degeneration. Conversely, ocular IP and tumor-related IP can combine to permit extensive tumor growth and increased risk of metastasis thus threatening the survival of the host.
Resumo:
Despite the growing use of apologies in post-conflict settings, cases of non-apology remain unaddressed and continue to puzzle scholars. This article focuses on the absence of apology by non-state and anti-state actors by examining the case of the Cypriot armed group EOKA, which has refused to offer an apology to the civilian victims of its ‘anti-colonial’ struggle (1955–1959). Using field data and parliamentary debates, and drawing on comparisons, this article analyses the factors that contributed to a lack of apology. It is argued that the inherited timelessness of Greek nationalism, and the impression of a perpetual need for defence, set up textbook conditions for the development of a hegemonic discourse and prevented an apology for human rights violations.
Resumo:
Non-Volatile Memory (NVM) technology holds promise to replace SRAM and DRAM at various levels of the memory hierarchy. The interest in NVM is motivated by the difficulty faced in scaling DRAM beyond 22 nm and, long-term, lower cost per bit. While offering higher density and negligible static power (leakage and refresh), NVM suffers increased latency and energy per memory access. This paper develops energy and performance models of memory systems and applies them to understand the energy-efficiency of replacing or complementing DRAM with NVM. Our analysis focusses on the application of NVM in main memory. We demonstrate that NVM such as STT-RAM and RRAM is energy-efficient for memory sizes commonly employed in servers and high-end workstations, but PCM is not. Furthermore, the model is well suited to quickly evaluate the impact of changes to the model parameters, which may be achieved through optimization of the memory architecture, and to determine the key parameters that impact system-level energy and performance.
Resumo:
Implementation of both design for durability and performance-based standards and specifications are limited by the lack of rapid, simple, science-based test methods for characterizing the transport properties and deterioration resistance of concrete. To this end, this paper presents the background rationale and current developments in the application of electrical property measurements - conductivity in this instance - as a testing methodology to evaluate the relative performance of a range of concrete mixes. The technique can not only be used on standard specimens (e.g. cubes), but also lends itself to in-situ monitoring thereby allowing measurements to be obtained on the as-placed concrete. It is the latter which forms the focus of the current work. Conductivity measurements are presented for concretes with and without supplementary cementitious materials (SCM's) from demoulding up to 400-days. It is shown that electrical conductivity measurements display a continual decrease over the entire test period and attributed to the pore structure refinement due to hydration and pozzolanic reaction in those concretes containing blast furnace slag or fly ash. The term Formation Factor is introduced to rank concrete performance in terms of is resistance to chloride penetration.
Resumo:
It is acknowledged that one of the consequences of the ageing process is cognitive decline, which leads to an increase in the incidence of illnesses such as dementia. This has become ever more relevant due to the projected increase in the ageing demographic. Dementia affects visuo-spatial perception, causing difficulty with wayfinding, even during the early stages of the disease. The literature widely recognises the physical environment’s role in alleviating symptoms of dementia and improving quality of life for residents. It also identifies the lack of available housing options for older people with dementia and consequently the current stock is ill-equipped to provide adequate support.
Recent statistics indicate that 80% of those residing in nursing or residential care homes have some form of dementia or severe memory problems. The shift towards institutional care settings, the need for specialist support and care, places a greater impetus on the need for a person-centred approach to tackle issues related to wayfinding and dementia.
This thesis therefore aims to improve design for dementia in nursing and residential care settings in the context of Northern Ireland. This will be undertaken in order to provide a better understanding of how people with dementia experience the physical environment and to highlight features of the design that assist with wayfinding. Currently there are limited guidelines on design for dementia, meaning that many of these are theoretical, anecdotal and not definitive. Hence a greater verification to address the less recognised design issues is required. This is intended to ultimately improve quality of life, wellbeing, independence and uphold the dignity of people with dementia living in nursing or residential care homes.
The research design uses a mixed methods approach. A thorough preparation and consideration of ethical issues informed the methodology. The various facets were also trialled and piloted to identify any ethical, technological, methodological, data collection and analysis issues. The protocol was then amended to improve or resolve any of the aforementioned issues. Initially a questionnaire based on leading design recommendations was conducted with home managers. Semi-structured interviews were developed from this and conducted with staff and resident’s next of kin. An evidence-based approach was used to design a study which used ethnographic methods, including a wayfinding task. This followed a repeated measures design which would be used to actively engage residents with dementia in the research. Complementary to the wayfinding task, conversational and semi-structured interviews were used to promote dialogue and direct responses with the person with dementia. In addition to this, Space Syntax methodologies were used to examine the physical properties of the architectural layout. This was then cross-examined with interview responses and data from the wayfinding tasks.
A number of plan typologies were identified and were determined as synonymous with decision point types which needed to be made during the walks. The empirical work enabled the synthesis of environmental features which support wayfinding.
Results indicate that particular environmental features are associated with improved performance on the wayfinding tasks. By enhancing design for dementia, through identifying the attributes, challenges with wayfinding may be overcome and the benefits of the physical environment can be seen to promote wellbeing.
The implications of this work mean that the environmental features which have been highlighted from the project can be used to inform guidelines, thus adding to existing knowledge. Future work would involve the dissemination of this information and the potential for it to be made into design standards or regulations which champion design for dementia. These would increase awareness for designers and stakeholders undertaking new projects, extensions or refurbishments.
A person-centred, evidence-based design was emphasised throughout the project which guaranteed an in-depth study. There were limitations due to the available resources, time and funding. Future research would involve testing the identified environmental features within a specific environment to enable measured observation of improvements.
Resumo:
This paper examines the position of planning practices operated under precise guidelines for displaying modernity. Cultivating the spatial qualities of Cairo since the 1970s has unveiled centralised ideologies and systems of governance and economic incentives. I present a discussion of the wounds that result from the inadequate upgrading ventures in Cairo, which I argue, created scars as enduring evidence of unattainable planning methods and processes that undermined its locales. In this process, the paper focuses on the consequences of eviction rather than the planning methods in one of the city’s traditional districts. Empirical work is based on interdisciplinary research, public media reports and archival maps that document actions and procedures put in place to alter the visual, urban, and demographic characteristics of Cairo’s older neighbourhoods against a backdrop of decay to shift towards a global spectacular. The paper builds a conversation about the power and fate these spaces were subject to during hostile transformations that ended with their being disused. Their existence became associated with sores on the souls of its ex-inhabitants, as outward signs of inward scars showcasing a lack of equality and social justice in a context where it was much needed.
Resumo:
The Northern Ireland peace process is often eulogized as a successful model of conflict transformation. Although the process exhibited many of the problems that beset other societies seeking to move from conflict to a negotiated peace (including disagreements over the functioning of institutions and the meanings of cultural symbols, unresolved issues relating to the effects of political violence on victims and survivors and society at large; and the residual presence of violent and political ‘spoiler’ groups), the resilience of political dialogue has proven remarkable.
This collection revisits the promise of ‘a truly historic opportunity for a new beginning’ a decade and a half on from the signing of the Belfast/Good Friday Agreement in 1998. The book will bring together academics from across a number of disciplines, including management and organizational behaviour, law, politics, sociology, archaeology and literature.
The different contributions aim to assess what impact it has made in the legal, policy, and institutional areas it specifically targeted: political reform, human rights and equality provision, working through legacies of the past (including police reform, prisoner release and victims' rights) and the building of new relationships within the island of Ireland and between Ireland and Britain. With the emergence of first-time voters who had no direct experience of the violence the book explores what the Agreement offers for future generations.
The book is the culmination of a 12-month research project sponsored by the British Academy and Leverhulme that addressed the following aspects of the peace process:
Peace walls: The euphemistically named peace walls remain one of the most visible reminders of Northern Ireland’s divisions and they are famously the only material manifestations of the conflict that have grown in number and extent since the 1998 Agreement. They were originally placed between antagonistic neighbouring communities – often at their request – at times of heightened tensions. Research under this theme explored the lack of ongoing engagement with their continuing presences, evolving meanings and impact on the communities that reside beside them needs to be overtly addressed.
Cultural division: Cultural differences have often been seen as lying at the heart of the ‘Irish problem’. Despite this, art and artists have increasingly been seen as having the potential to develop new discourses. Research explored the following questions: What role can the arts play in re-imagining the spaces opened up by the promises of the 1998 Agreement? What implication does the confrontation with the legacies of conflict have for artistic practices? What impact do the arts have on constructions of identity, on narratives of history, and on electoral politics?
Institutional transformation: This strand of research explored the significance of the process of organizational change which followed the establishment of the 1998 on political and other public policy institutions such as the police and prison services. It suggested that the experience and lessons learned from such periods of transition have much to contribute to how Northern Ireland begins to address political polarization in other areas of public service infrastructure, chiefly around the sectarian monoliths of education and housing.
Working through the past: ‘Legacy’ issues have gained increasing prominence since 1998: issues to do with public symbolism (particularly relating to the flying of flags and parading), defining victimhood, securing victims’ rights, recovery of the ‘disappeared’, reintegrating ex- prisoners back into society, and the possibilities for truth recovery and reconciliation have all acquired salient and emotive force. Although the 1998 Agreement promised to ‘honour the dead’ through a ‘new beginning’, it is increasingly unclear as to whether an agreed narrative about the past is possible – or even worthwhile pursuing. Research under this theme looked at the complex relationship between memory, commemoration and violence; how commemorative events are performed, organized, policed and represented. It also addressed the fraught issue of how to come to terms with Northern Ireland’s divided and bloodied past.
The editors are in the process of guiding contributors to adapt their papers, which were presented to a series of workshops on the above themes, to the purposes of the book. In particular, the contributors will be guided to focus on the related aims of assessing the extent of change that has occurred and providing an assessment of what remains to be done. To that end, contributors are asked to engage directly with the questions that close the ‘Introduction’, namely: To what extent has the ‘promise’ of the 1998 Agreement been fulfilled? To what extent has the 1998 Agreement given rise to forms of exclusion? To what extent has the 1998 Agreement shaped new forms of debate, dispute and engagement? In the absence of that guidance having been sent out yet, the outlines below are, for the time being, the abstracts of their original papers.
Resumo:
This article will discuss notions and concepts of remembering in the aftermath of the Charlie Hebdo attacks. Much has been written about the immediate response to the attacks, both commending the collective spirit of unity that defined the ‘marche républicaine’ of 11 January 2015, and criticising the alleged hypocrisy and cynicism of, most notably, the political figures that took to the streets that day, hand in hand. I will consider a selection of the memory practices that have emerged since then, notably on the anniversary of the event. This demonstration of memory provides key insights into the form and manner of remembering within a particular cultural group, but also reflects how the present moment is integral to our understanding of memory. The purpose of this article is to consider how official and non-official remembering of Charlie Hebdo can intertwine as well as pull in separate directions. A focus on the politics, the language, the aesthetics and the geography of commemorative activities in this article will enable an appreciation of the multidirectional character of remembering Charlie Hebdo.