792 resultados para memory reactivation


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The aim of this paper is to address some theoretical issues concerning the narrative practice in cyberspace. From a narratological perspective it intends to clarify the functioning of time and space in storytelling. For that purpose it traces the concept(s) of memory inherited from rhetoric; the use of memory as a narrative device in traditional accounts; the adaptations imposed by hyperfiction. Using practical examples (including two Portuguese case studies - InStory 2006, and Noon 2007) it will show how narrative memory strategies can be helpful in game literacy. The main purpose is to contribute to serious game research and (trans)literary studies.

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Dissertação para obtenção do Grau de Mestre em Engenharia Química e Bioquímica

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Shape memory alloys are characterized by the ability of recovering their initial shape after being deformed and by superelasticity. Since the discovery of these alloys, a new field of interest emerged not only for the scientific community but also to many industries. However, these alloys present poor machinability which constitute a constrain in the design of complex components for new applications. Thus, the demand for joining techniques able to join these alloys without compromising their properties became of great importance to enlarge the complexity of existing applications. Literature shows that these alloys are joined mainly using laser welding. In the present study, similar NiTi butt joints, were produced using TIG welding. The welds were performed in 1.5 mm thick plates across the rolling direction. A special fixture and gas assist device was designed and manufactured. Also a robot arm was adapted to accommodate the welding torch to assure the repeatability of the welding parameters. Welds were successfully achieved without macroscopic defects, such as pores and distortions. Very superficial oxidation was seen on the top surface due to insufficient shielding gas flow on the weld face. The welded joints were mechanically tested and structurally characterized. Testing methods were used to evaluate macro and microstructure, as well as the phase transformation temperatures, the mechanical single and cyclic behaviour and the shape recovery ability. Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), microhardness measurements were techniques also used to evaluate the welded joints. A depletion in Ni in the fusion zone was seen, as well as a shift in Ms temperature. For strain values of 4% the accumulated irrecoverable strain was of about 30% and increased with the strain imposed during cycling. Nevertheless, a complete recovery of initial shape was observed when testing the shape memory effect on a dedicated device that introduces a deformation of 6.7%. That is, the welding procedure does not remove the ability of the specimens to recover their initial shape.

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The project of writing to a fictional Portuguese-speaking Queen on the crises proceeding since 2008 builds on Letters to Queen Elizabeth written by the British Academy and was first published in 2013. This expanded edition signals greater awareness of the complementarity between economic potential and cultural legacy in the Community of Portuguese-speaking Countries (CPLP) insofar as its members, observers and their areas of economic integration encompass the globe. The edition is dedicated to the memory of Manuel Jacinto Nunes, who supported the project as dean of the economics section at the Lisbon Academy of Science. The cover shows a Crown with nine CPLP flags as jewels in the shape of a 7 rising from the waves. The waves of lusophonia appear far gentler than Poe’s maelstrom, reproduced in the back flap. This material, inserted in the proceedings published on IICT’s 130th anniversary, is used at NOVASBE through its Center for Globalization and Governance (CG&G).

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The next pages will describe my experience and results of making connections between cognitive sciences and art; the transformations of my memories being the object of study and motivation for this process of self-discovery. The human body reacts according to innumerable neural functions and external stimuli. Neurons respond to the evocation of experienced events, building virtual images, map-like constellations sometimes fulfilled by imagination, desires or knowledge promoting in this way their constant reshaping. This document offers an insight into my recollections as matter. As matter these recollections take on different states and I hope to give you a better sense of my personal voice using my experience with glass to explore this transformation and accompanying my journey with lectures and scientific readings about the mind functions.

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This paper studies the drivers of heuristic application in different decision types. The study compares differences in frequencies of heuristic classes' such as recognition, one-reason choice and trade-off applied in, respectively, memory-based and stimulus-based choices as well as in high and low involvement decisions. The study has been conducted online among 205 participants from 28 countries.

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ABSTRACT: Background. In India, prevalence rates of dementia and prodromal amnestic Mild Cognitive Impairment (MCI) are 3.1% and 4.3% respectively. Most Indians refer to the full spectrum of cognitive disorders simply as ‘memory loss.’ Barring prevention or cure, these conditions will rise rapidly with population aging. Evidence-based policies and practices can improve the lives of affected individuals and their caregivers, but will require timely and sustained uptake. Objectives. Framed by social cognitive theories of health behavior, this study explores the knowledge, attitudes and practices concerning cognitive impairment and related service use by older adults who screen positive for MCI, their primary caregivers, and health providers. Methods. I used the Montreal Cognitive Assessment to screen for cognitive impairment in memory camps in Mumbai. To achieve sampling diversity, I used maximum variation sampling. Ten adults aged 60+ who had no significant functional impairment but screened positive for MCI and their caregivers participated in separate focus groups. Four other such dyads and six doctors/ traditional healers completed in-depth interviews. Data were translated from Hindi or Marathi to English and analyzed in Atlas.ti using Framework Analysis. Findings. Knowledge and awareness of cognitive impairment and available resources were very low. Physicians attributed the condition to disease-induced pathology while lay persons blamed brain malfunction due to normal aging. Main attitudes were that this condition is not a disease, is not serious and/or is not treatable, and that it evokes stigma toward and among impaired persons, their families and providers. Low knowledge and poor attitudes impeded help-seeking. Conclusions. Cognitive disorders of aging will take a heavy toll on private lives and public resources in developing countries. Early detection, accurate diagnosis, systematic monitoring and quality care are needed to compress the period of morbidity and promote quality of life. Key stakeholders provide essential insights into how scientific and indigenous knowledge and sociocultural attitudes affect use and provision of resources.

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In this study in the field of Consumer Behavior, brand name memory of consumers with regard to verbal and visual incongruent and congruent information such as memory structure of brands was tested. Hence, four experimental groups with different constellations of verbal and visual congruity and incongruity were created to compare their brand name memory performance. The experiment was conducted in several classes with 128 students, each group with 32 participants. It was found that brands, which are presented in a congruent or moderately incongruent relation to their brand schema, result in a better brand recall than their incongruent counterparts. A difference between visual congruity and moderately incongruity could not be confirmed. In contrast to visual incongruent information, verbal incongruent information does not result in a worse brand recall performance.

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The aim of this study was to evaluated the efficacy of the Old Way/New Way methodology (Lyndon, 1989/2000) with regard to the permanent correction of a consolidated and automated technical error experienced by a tennis athlete (who is 18 years old and has been engaged in practice mode for about 6 years) in the execution of serves. Additionally, the study assessed the impact of intervention on the athlete’s psychological skills. An individualized intervention was designed using strategies that aimed to produce a) a detailed analysis of the error using video images; b) an increased kinaesthetic awareness; c) a reactivation of memory error; d) the discrimination and generalization of the correct motor action. The athlete’s psychological skills were measured with a Portuguese version of the Psychological Skills Inventory for Sports (Cruz & Viana, 1993). After the intervention, the technical error was corrected with great efficacy and an increase in the athlete’s psychological skills was verified. This study demonstrates the methodology’s efficacy, which is consistent with the effects of this type of intervention in different contexts.

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Mutable state can be useful in certain algorithms, to structure programs, or for efficiency purposes. However, when shared mutable state is used in non-local or nonobvious ways, the interactions that can occur via aliases to that shared memory can be a source of program errors. Undisciplined uses of shared state may unsafely interfere with local reasoning as other aliases may interleave their changes to the shared state in unexpected ways. We propose a novel technique, rely-guarantee protocols, that structures the interactions between aliases and ensures that only safe interference is possible. We present a linear type system outfitted with our novel sharing mechanism that enables controlled interference over shared mutable resources. Each alias is assigned separate, local roles encoded in a protocol abstraction that constrains how an alias can legally use that shared state. By following the spirit of rely-guarantee reasoning, our rely-guarantee protocols ensure that only safe interference can occur but still allow many interesting uses of shared state, such as going beyond invariant and monotonic usages. This thesis describes the three core mechanisms that enable our type-based technique to work: 1) we show how a protocol models an alias’s perspective on how the shared state evolves and constrains that alias’s interactions with the shared state; 2) we show how protocols can be used while enforcing the agreed interference contract; and finally, 3) we show how to check that all local protocols to some shared state can be safely composed to ensure globally safe interference over that shared memory. The interference caused by shared state is rooted at how the uses of di↵erent aliases to that state may be interleaved (perhaps even in non-deterministic ways) at run-time. Therefore, our technique is mostly agnostic as to whether this interference was the result of alias interleaving caused by sequential or concurrent semantics. We show implementations of our technique in both settings, and highlight their di↵erences. Because sharing is “first-class” (and not tied to a module), we show a polymorphic procedure that enables abstract compositions of protocols. Thus, protocols can be specialized or extended without requiring specific knowledge of the interference produce by other protocols to that state. We show that protocol composition can ensure safety even when considering abstracted protocols. We show that this core composition mechanism is sound, decidable (without the need for manual intervention), and provide an algorithm implementation.

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This work will discuss the use of different paper membranes as both the substrate and dielectric for field-effect memory transistors. Three different nanofibrillated cellulose membranes (NFC) were used as the dielectric layer of the memory transistors (NFC), one with no additives, one with an added polymer PAE and one with added HCl. Gallium indium zinc oxide (GIZO) was used as the device’s semiconductor and gallium aluminium zinc oxide (GAZO) was used as the gate electrode. Fourier transform infrared spectroscopy (FTIR) was used to access the water content of the paper membranes before and after vacuum. It was found that the devices recovered their water too quickly for a difference to be noticeable in FTIR. The transistor’s electrical performance tests yielded a maximum ION/IOFF ratio of around 3,52x105 and a maximum subthreshold swing of 0,804 V/decade. The retention time of the dielectric charge that grants the transistor its memory capabilities was accessed by the measurement of the drain current periodically during 144 days. During this period the mean drain current did not lower, leaving the retention time of the device indeterminate. These results were compared with similar devices revealing these devices to be at the top tier of the state-of-the-art.

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Current computer systems have evolved from featuring only a single processing unit and limited RAM, in the order of kilobytes or few megabytes, to include several multicore processors, o↵ering in the order of several tens of concurrent execution contexts, and have main memory in the order of several tens to hundreds of gigabytes. This allows to keep all data of many applications in the main memory, leading to the development of inmemory databases. Compared to disk-backed databases, in-memory databases (IMDBs) are expected to provide better performance by incurring in less I/O overhead. In this dissertation, we present a scalability study of two general purpose IMDBs on multicore systems. The results show that current general purpose IMDBs do not scale on multicores, due to contention among threads running concurrent transactions. In this work, we explore di↵erent direction to overcome the scalability issues of IMDBs in multicores, while enforcing strong isolation semantics. First, we present a solution that requires no modification to either database systems or to the applications, called MacroDB. MacroDB replicates the database among several engines, using a master-slave replication scheme, where update transactions execute on the master, while read-only transactions execute on slaves. This reduces contention, allowing MacroDB to o↵er scalable performance under read-only workloads, while updateintensive workloads su↵er from performance loss, when compared to the standalone engine. Second, we delve into the database engine and identify the concurrency control mechanism used by the storage sub-component as a scalability bottleneck. We then propose a new locking scheme that allows the removal of such mechanisms from the storage sub-component. This modification o↵ers performance improvement under all workloads, when compared to the standalone engine, while scalability is limited to read-only workloads. Next we addressed the scalability limitations for update-intensive workloads, and propose the reduction of locking granularity from the table level to the attribute level. This further improved performance for intensive and moderate update workloads, at a slight cost for read-only workloads. Scalability is limited to intensive-read and read-only workloads. Finally, we investigate the impact applications have on the performance of database systems, by studying how operation order inside transactions influences the database performance. We then propose a Read before Write (RbW) interaction pattern, under which transaction perform all read operations before executing write operations. The RbW pattern allowed TPC-C to achieve scalable performance on our modified engine for all workloads. Additionally, the RbW pattern allowed our modified engine to achieve scalable performance on multicores, almost up to the total number of cores, while enforcing strong isolation.

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Bioactive glass nanoparticles (BGNPs) promote an apatite surface layer in physiologic conditions that lead to a good interfacial bonding with bone.1 A strategy to induce bioactivity in non-bioactive polymeric biomaterials is to incorporate BGNPs in the polymer matrix. This combination creates a nanocomposite material with increased osteoconductive properties. Chitosan (CHT) is a polymer obtained by deacetylation of chitin and is biodegradable, non-toxic and biocompatible. The combination of CHT and the BGNPs aims at designing biocompatible spheres promoting the formation of a calcium phosphate layer at the nanocomposite surface, thus enhancing the osteoconductivity behaviour of the biomaterial. Shape memory polymers (SMP) are stimuli-responsive materials that offer mechanical and geometrical action triggered by an external stimulus.2 They can be deformed and fixed into a temporary shape which remains stable unless exposed to a proper stimulus that triggers recovery of their original shape. This advanced functionality makes such SMPs suitable to be implanted using minimally invasive surgery procedures. Regarding that, the inclusion of therapeutic molecules becomes attractive.  We propose the synthesis of shape memory bioactive nanocomposite spheres with drug release capability.3   1.  L. L. Hench, Am. Ceram. Soc. Bull., 1993, 72, 93-98. 2.  A. Lendlein and S. Kelch, Angew Chem Int Edit, 2002, 41, 2034-2057. 3.  Ã . J. Leite, S. G. Caridade and J. F. Mano, Journal of Non-Crystalline Solids (in Press)

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The free volume holes of a shape memory polymer have been analysed considering that the empty space between molecules is necessary for the molecular motion, and the shape memory response is based on polymer segments acting as molecular switches through variable flexibility with temperature or other stimuli. Therefore, thermomechanical analysis (TMA) and positron annihilation lifetime spectroscopy (PALS) have been applied to analyse shape recovery and free volume hole sizes in gamma irradiated polycyclooctene (PCO) samples, as a non-cytotoxic alternative to more conventional PCO crosslinked via peroxide for future applications in medicine. Thus, a first approach relating structure, free volume holes and shape memory properties in gamma irradiated PCO is presented. The results suggest that free volume holes caused by gamma irradiation in PCO samples facilitate the recovery process by improving movement of polymer chains and open t possibilities for the design and control of the macroscopic response.

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In this work, hafnium aluminum oxide (HfAlO) thin films were deposited by ion beam sputtering deposition technique on Si substrate. The presence of oxygen vacancies in the HfAlOx layer deposited in oxygen deficient environment is evidenced from the photoluminescence spectra. Furthermore, HfAlO(oxygen rich)/HfAlOx(oxygen poor) bilayer structures exhibit multilevel resistive switching (RS), and the switching ratio becomes more prominent with increasing the HfAlO layer thickness. The bilayer structure with HfAlO/HfAlOx thickness of 30/40 nm displays the enhanced multilevel resistive switching characteristics, where the high resistance state/ intermediate resistance state (IRS) and IRS/low resistance state resistance ratios are 102 and 5 105 , respectively. The switching mechanisms in the bilayer structures were investigated by the temperature dependence of the three resistance states. This study revealed that the multilevel RS is attributed to the coupling of ionic conduction and the metallic conduction, being the first associated to the formation and rupture of conductive filaments related to oxygen vacancies and the second with the formation of a metallic filament. Moreover, the bilayer structures exhibit good endurance and stability in time.