962 resultados para Ferroelectric memories


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"Christy Dena’s online-remix-narrative takes iconic images of popular culture and builds with them a strange world where the human fallibility is programmatically deleted. Both dystopic and playful, Dena’s work is an ironic reimagining of pleasure as a state of robotic flatlining, using tropes of science fiction to critique processes of social normalisation and increasing alienation from emotionality." This creative response began as a completely different story and form. What excited me in the end was the concept of deletion and how it could be an interesting mechanic: where the only thing you can do in the world is delete. I thought about deleting parts of robots to make them better. Healing comes from taking away, from removing things. Memories of Joseph Weizenbaum’s chatbot ELIZA came flooding back: where the (human) player is a patient talking to a Rogerian psychotherapist. But in this work I’m switching the roles and making the player the doctor, a doctor to robots…a doctor that can only prescribe deletions. I conceived of the work as a branching narrative, and started writing it in Twine. With every robot patient, the player chose one of many deletions. But when I realised I wouldn’t be able to arrange an artist and sound designer I looked for another option. I played with Zeega and felt that I could get the mood I was after with that platform. So the piece transformed into a work where the player/viewer is imprisoned in the decisions of the deleting protagonist…which has its own effect on the experience and meaning.

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Priceite is a calcium borate mineral and occurs as white crystals in the monoclinic pyramidal crystal system. We have used a combination of Raman spectroscopy with complimentary infrared spectroscopy and scanning electron microscopy with Energy-dispersive X-ray Spectroscopy (EDS) to study the mineral priceite. Chemical analysis shows a pure phase consisting of B and Ca only. Raman bands at 956, 974, 991, and 1019 cm−1 are assigned to the BO stretching vibration of the B10O19 units. Raman bands at 1071, 1100, 1127, 1169, and 1211 cm−1 are attributed to the BOH in-plane bending modes. The intense infrared band at 805 cm−1 is assigned to the trigonal borate stretching modes. The Raman band at 674 cm−1 together with bands at 689, 697, 736, and 602 cm−1 are assigned to the trigonal and tetrahedral borate bending modes. Raman spectroscopy in the hydroxyl stretching region shows a series of bands with intense Raman band at 3555 cm−1 with a distinct shoulder at 3568 cm−1. Other bands in this spectral region are found at 3221, 3385, 3404, 3496, and 3510 cm−1. All of these bands are assigned to water stretching vibrations. The observation of multiple bands supports the concept of water being in different molecular environments in the structure of priceite. The molecular structure of a natural priceite has been assessed using vibrational spectroscopy.

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Feminist research on girlhood has drawn extensively on Butler's conceptual work in order to theorise the normative forces of heterosexuality in the everyday construction of gender. This chapter explores girlhood by drawing on memories and artwork generated in a collective biography workshop held in Australian on the topic of girlhood and sexuality. We are interested in thinking through Butler's notion of the heterosexual matrix. Following Renold and Ringrose (2008) we do so with the help of Deleuze and Guattari, who invite us to think about difference as differenciation or continuous becoming, where difference is an evolutionary multiplicity.

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The mineral meliphanite (Ca,Na)2Be[(Si,Al)2O6(F,OH)] is a crystalline sodium calcium beryllium silicate which has the potential to be used as piezoelectric material and for other ferroelectric applications. The mineral has been characterized by a combination of scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) and vibrational spectroscopy. EDS analysis shows a material with high concentrations of Si and Ca and low amounts of Na, Al and F. Beryllium was not detected. Raman bands at 1016 and 1050 cm−1 are assigned to the SiO and AlOH stretching vibrations of three dimensional siloxane units. The infrared spectrum of meliphanite is very broad in comparison with the Raman spectrum. Raman bands at 472 and 510 cm−1 are assigned to OSiO bending modes. Raman spectroscopy identifies bands in the OH stretching region. Raman spectroscopy with complimentary infrared spectroscopy enables the characterization of the silicate mineral meliphanite.

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A home embodies a sensorial space that is layered with personal memories and traces of history. The success of a home in providing a strong sense of place depends on various factors such as geographical location, climatic conditions, and occupants’ world-views and perceptions. This paper explores Muslims’ perceptions of privacy, modesty and hospitality within their homes through their lived experiences. This case study focuses on three Muslim families living in Australian designed homes within the same suburb of Brisbane, Australia. The study provides prefatory insight into the ways in which these families perform their daily activities and entertain their guests without jeopardizing their privacy needs. The study examines the significance of modesty in the design of Muslim homes as a means by which family members are able to achieve optimum privacy while simultaneously extending hospitality to guests inside and outside their homes. The findings of this study provide opportunities too, for expanding research into culturally adaptable housing systems to help meet the changing needs of Australian multicultural society.

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National or International Significance Flows of cultural heritage in textual practices are vital to sustaining Indigenous communities - a national and international priority (Commonwealth of Australia, 2011). Indigenous heritage, whether passed on by oral tradition or ubiquitous social media, can be seen as a "conversation between the past and the future" (Fairclough, 2012, p. xv). Indigenous heritage involves appropriating memories within a cultural flow to pass on a spiritual legacy. This presentation reports ethnographic research of social media practices in a small independent Aboriginal school in Southeast Queensland, Australia that is resided over by the Yuggera elders and an Aboriginal principal. Quality of Research The purpose was to rupture existing notions of white literacies in schools, and to deterritorialize the uses of digital media by dominant cultures in the public sphere. Examples of learning experiences included the following: i. Integrating Indigenous language and knowledge into media text production; ii. Classroom visits from Indigenous elders; and iii. Publishing oral histories through digital scrapbooking. The program aligned with the Australian National Curriculum English (ACARA, 2014), which mandates the teaching of multimodal text creation. Data sources included a class set of digital scrapbooks collaboratively created in a preparatory-one primary classroom. The digital scrapbooks combined digitally encoded words, images of material artifacts, and digital music files. A key feature of the writing and digital design task was to retell and digitally display and archive a cultural narrative of significance to the Indigenous Australian community and its memories and material traces of the past for the future. Data analysis of the students' digital stories involved the application of key themes of negotiated, material, and digitally mediated forms of heritage practice. It drew on Australian Indigenous research by Keddie et al. (2013) to guard against the homogenizing of culture that can arise from a focus on a static view of culture. The interpretation of findings located Indigenous appropriation of social media within broader racialized politics that enables Indigenous literacy to be understood as a dynamic, negotiated, and transgenerational flows of practice. It demonstrates that Indigenous children's use of media production reflects "shifting and negotiated identities" in response to changing media environments that can function to sustain Indigenous cultural heritages (Appadurai, 1696, p. xv). Impact on practice, policy or theory The findings are important for teachers at a time when Aboriginal and Torres Strait Islander Histories and Cultures is a cross-curricular policy priority in the Australian Curriculum (ACARA, 2014). The findings show how curriculum policies can be applied to classroom practice in ways that are epistemologically consistent with Indigenous ways of knowing and being. Theoretically, it demonstrates how the children's experiences of culture are layered over time, as successive generations inherit, interweave, and hear others' cultural stories or maps. Practically, recommendations are provided for an approach to appropriating social media in schools that explicitly attends to the dynamic nature of Indigenous practices, negotiated through intercultural constructions and flows, and opening space for a critical anti-racist approach to multimodal text production. Timeliness The research is timely in the context of the accessibility and role of digital and multimodal forms of communication, including for Aboriginal and Torres Strait Islander communities.

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The hippocampus is an anatomically distinct region of the medial temporal lobe that plays a critical role in the formation of declarative memories. Here we show that a computer simulation of simple compartmental cells organized with basic hippocampal connectivity is capable of producing stimulus intensity sensitive wide-band fluctuations of spectral power similar to that seen in real EEG. While previous computational models have been designed to assess the viability of the putative mechanisms of memory storage and retrieval, they have generally been too abstract to allow comparison with empirical data. Furthermore, while the anatomical connectivity and organization of the hippocampus is well defined, many questions regarding the mechanisms that mediate large-scale synaptic integration remain unanswered. For this reason we focus less on the specifics of changing synaptic weights and more on the population dynamics. Spectral power in four distinct frequency bands were derived from simulated field potentials of the computational model and found to depend on the intensity of a random input. The majority of power occurred in the lowest frequency band (3-6 Hz) and was greatest to the lowest intensity stimulus condition (1% maximal stimulus). In contrast, higher frequency bands ranging from 7-45 Hz show an increase in power directly related with an increase in stimulus intensity. This trend continues up to a stimulus level of 15% to 20% of the maximal input, above which power falls dramatically. These results suggest that the relative power of intrinsic network oscillations are dependent upon the level of activation and that above threshold levels all frequencies are damped, perhaps due to over activation of inhibitory interneurons.

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A hippocampal-CA3 memory model was constructed with PGENESIS, a recently developed version of GENESIS that allows for distributed processing of a neural network simulation. A number of neural models of the human memory system have identified the CA3 region of the hippocampus as storing the declarative memory trace. However, computational models designed to assess the viability of the putative mechanisms of storage and retrieval have generally been too abstract to allow comparison with empirical data. Recent experimental evidence has shown that selective knock-out of NMDA receptors in the CA1 of mice leads to reduced stability of firing specificity in place cells. Here a similar reduction of stability of input specificity is demonstrated in a biologically plausible neural network model of the CA3 region, under conditions of Hebbian synaptic plasticity versus an absence of plasticity. The CA3 region is also commonly associated with seizure activity. Further simulations of the same model tested the response to continuously repeating versus randomized nonrepeating input patterns. Each paradigm delivered input of equal intensity and duration. Non-repeating input patterns elicited a greater pyramidal cell spike count. This suggests that repetitive versus non-repeating neocortical inpus has a quantitatively different effect on the hippocampus. This may be relevant to the production of independent epileptogenic zones and the process of encoding new memories.

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As the key neuron-to-neuron interface, the synapse is involved in learning and memory, including traumatic memories during times of stress. However, the signal transduction mechanisms by which stress mediates its lasting effects on synapse transmission and on memory are not fully understood. A key component of the stress response is the increased secretion of adrenal steroids. Adrenal steroids (e.g., cortisol) bind to genomic mineralocorticoid and glucocorticoid receptors (gMRs and gGRs) in the cytosol. In addition, they may act through membrane receptors (mMRs and mGRs), and signal transduction through these receptors may allow for rapid modulation of synaptic transmission as well as modulation of membrane ion currents. mMRs increase synaptic and neuronal excitability; mechanisms include the facilitation of glutamate release through extracellular signal-regulated kinase signal transduction. In contrast, mGRs decrease synaptic and neuronal excitability by reducing calcium currents through N-methyl-D-aspartate receptors and voltage-gated calcium channels by way of protein kinase A- and G protein-dependent mechanisms. This body of functional data complements anatomical evidence localizing GRs to the postsynaptic membrane. Finally, accumulating data also suggest the possibility that mMRs and mGRs may show an inverted U-shaped dose response, whereby glutamatergic synaptic transmission is increased by low doses of corticosterone acting at mMRs and decreased by higher doses acting at mGRs. Thus, synaptic transmission is regulated by mMRs and mGRs, and part of the stress signaling response is a direct and bidirectional modulation of the synapse itself by adrenal steroids.

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The lateral amygdala (LA) receives information from auditory and visual sensory modalities, and uses this information to encode lasting memories that predict threat. One unresolved question about the amygdala is how multiple memories, derived from different sensory modalities, are organized at the level of neuronal ensembles. We previously showed that fear conditioning using an auditory conditioned stimulus (CS) was spatially allocated to a stable topography of neurons within the dorsolateral amygdala (LAd) (Bergstrom et al, 2011). Here, we asked how fear conditioning using a visual CS is topographically organized within the amygdala. To induce a lasting fear memory trace we paired either an auditory (2 khz, 55 dB, 20 s) or visual (1 Hz, 0.5 s on/0.5 s off, 35 lux, 20 s) CS with a mild foot shock unconditioned stimulus (0.6 mA, 0.5 s). To detect learning-induced plasticity in amygdala neurons, we used immunohistochemistry with an antibody for phosphorylated mitogen-activated protein kinase (pMAPK). Using a principal components analysis-based approach to extract and visualize spatial patterns, we uncovered two unique spatial patterns of activated neurons in the LA that were associated with auditory and visual fear conditioning. The first spatial pattern was specific to auditory cued fear conditioning and consisted of activated neurons topographically organized throughout the LAd and ventrolateral nuclei (LAvl) of the LA. The second spatial pattern overlapped for auditory and visual fear conditioning and was comprised of activated neurons located mainly within the LAvl. Overall, the density of pMAPK labeled cells throughout the LA was greatest in the auditory CS group, even though freezing in response to the visual and auditory CS was equivalent. There were no differences detected in the number of pMAPK activated neurons within the basal amygdala nuclei. Together, these results provide the first basic knowledge about the organizational structure of two different fear engrams within the amygdala and suggest they are dissociable at the level of neuronal ensembles within the LA

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Post traumatic stress disorder (PTSD) is a serious medical condition effecting both military and civilian populations. While its etiology remains poorly understood it is characterized by high and prolonged levels of fear responding. One biological unknown is whether individuals expressing high or low conditioned fear memory encode the memory differently and if that difference underlies fear response. In this study we examined cellular mechanisms that underlie high and low conditioned fear behavior by using an advanced intercrossed mouse line (B6D2F1) selected for high and low Pavlovian fear response. A known requirement for consolidation of fear memory, phosphorylated mitogen activated protein kinase (p44/42 (ERK) MAPK (pMAPK)) in the lateral amygdala (LA) is a reliable marker of fear learning-related plasticity. In this study, we asked whether high and low conditioned fear behavior is associated with differential pMAPK expression in the LA and if so, is it due to an increase in neurons expressing pMAPK or increased pMAPK per neuron. To examine this, we quantified pMAPK-expressing neurons in the LA at baseline and following Pavlovian fear conditioning. Results indicate that high fear phenotype mice have more pMAPK-expressing neurons in the LA. This finding suggests that increased endogenous plasticity in the LA may be a component of higher conditioned fear responses and begins to explain at the cellular level how different fear responders encode fear memories. Understanding how high and low fear responders encode fear memory will help identify novel ways in which fear-related illness risk can be better predicted and treated.

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Emotionally significant memories, especially those induced in conjunction with physical and mental trauma, are frequently retained for an individual’s lifetime. How these memories are organized and encoded within neural networks is a fundamental question. The lateral amygdala (LA) is a key nucleus for acquisition and maintenance of associative emotional memories. We used Pavlovian fear conditioning to study how ‘weaker’ and ‘stronger’ memories are encoded in neural networks of the LA. In Pavlovian fear conditioning a neutral stimulus, in this case a tone, is temporally paired with an aversive unconditioned stimulus (US), such as a foot shock. The previously neutral stimulus becomes a conditioned stimulus (CS) capable of eliciting defensive responses. We used time spent freezing when the CS is presented in a neutral context as a dependent variable measure of memory ‘strength’.

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Narrating is simultaneously self-interpretation and self-construction. People make sense of their lives and create their identities through an active process of assembling and applying meaning to memories, experiences, thoughts, actions and passions. Such a process can usefully be described as a bricolage: life narratives are created as an assemblage of scattered experiences and events. Through the particular way in which they are arranged, the storyteller constructs what Paul Ricoeur (1992) calls a “narrative identity”; that is, an identity which is organised through and specific to the story told. Applying this notion of narrative as bricolage to ‘Heywire’ – an Australian youth life storytelling project – this paper discusses the unique affordances that the process of storytelling offers in terms of identity and the way new, digital technologies and the internet augment the features of life narratives. It argues that narrative, in addition to new media, offers important tools through which young people who participate in the Heywire project make sense of personal experiences and craft their own identities in powerful and purposeful ways.

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This study uses the concept of ‘place-making’ to consider political engagement on Sina Weibo, one of the most popular microblogging services in China. Besides articulating statepublic confrontation during major social controversies, Weibo has been used to recollect and renarrate the memories of a city, such as Guangzhou, where dramatic social and cultural changes took place during the economic reform era. The Chinese government’s ongoing project to create a culturally indifferent ‘national identity’ triggers a defensive response from local places. Through consuming news and information about leisure and entertainment in Guangzhou, the digital narration of the city becomes an important source for Guangzhou people to learn about their geo-identity, and the kind of rights and responsibility attaching to it.

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The lateral amygdala (LA) has been extensively implicated in the neurobiology of conditioned fear paradigms. Norepinepherine (NE), especially its beta receptors, has been implicated in consolidation, reconsolidation and extinction of fear memories, and has been proposed as a potential treatment for PTSD (Berlau and McGaugh, NLM, 2006; Debiec and LeDoux, N, 2005)...