403 research outputs found

    Creation of pure non-crystalline diamond nanostructures via room-temperature ion irradiation and subsequent thermal annealing

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    Carbon exhibits a remarkable range of structural forms, due to the availability of sp3, sp2 and sp1 chemical bonds. Contrarily to other group IV elements such as silicon and germanium, the formation of an amorphous phase based exclusively on sp3 bonds is extremely challenging due to the strongly favored formation of graphitic-like structures at room 19 temperature and pressure. As such, the formation of a fully sp3-bonded carbon phase requires 20 an extremely careful (and largely unexplored) definition of the pressure and temperature across the phase diagram. Here, we report on the possibility of creating full-sp3 amorphous nanostructures within the bulk crystal of diamond with room-temperature ion-beam irradiation, followed by an annealing process that does not involve the application of any external mechanical pressure. As confirmed by numerical simulations, the (previously unreported) radiation-damage-induced formation of an amorphous sp2-free phase in diamond is determined by the buildup of extremely high internal stresses from the surrounding lattice, which (in the case of nanometer-scale regions) fully prevent the graphitization process. Besides the relevance of understanding the formation of exotic carbon phases, the use of focused/collimated ion beams discloses appealing perspectives for the direct fabrication of such nanostructures in complex three-dimensional geometries

    Inter-individual differences in vicarious tactile perception: A view across the lifespan in typical and atypical populations

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    Touch is our most interpersonal sense, and so it stands to reason that we represent not only our own bodily experiences, but also those felt by others. This review will summarise brain and behavioural research on vicarious tactile perception (mirror touch). Specifically, we will focus on vicarious touch across the lifespan in typical and atypical groups, and will identify the knowledge gaps that are in urgent need of filling by examining what is known about how individuals differ within and between typical and atypical groups

    A new study of 25^{25}Mg(α\alpha,n)28^{28}Si angular distributions at EαE_\alpha = 3 - 5 MeV

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    The observation of 26^{26}Al gives us the proof of active nucleosynthesis in the Milky Way. However the identification of the main producers of 26^{26}Al is still a matter of debate. Many sites have been proposed, but our poor knowledge of the nuclear processes involved introduces high uncertainties. In particular, the limited accuracy on the 25^{25}Mg(α\alpha,n)28^{28}Si reaction cross section has been identified as the main source of nuclear uncertainty in the production of 26^{26}Al in C/Ne explosive burning in massive stars, which has been suggested to be the main source of 26^{26}Al in the Galaxy. We studied this reaction through neutron spectroscopy at the CN Van de Graaff accelerator of the Legnaro National Laboratories. Thanks to this technique we are able to discriminate the (α\alpha,n) events from possible contamination arising from parasitic reactions. In particular, we measured the neutron angular distributions at 5 different beam energies (between 3 and 5 MeV) in the \ang{17.5}-\ang{106} laboratory system angular range. The presented results disagree with the assumptions introduced in the analysis of a previous experiment.Comment: 9 pages, 9 figures - accepted by EPJ

    In-doped Sb nanowires grown by MOCVD for high speed phase change memories

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    We investigated the Phase Change Memory (PCM) capabilities of In-doped Sb nanowires (NWs) with diameters of (20-40) nm, which were self-assembled by Metalorganic Chemical Vapor Deposition (MOCVD) via the vapor-liquid-solid (VLS) mechanism. The PCM behavior of the NWs was proved, and it was shown to have relatively low reset power consumption (~ 400 μW) and fast switching capabilities with respect to standard Ge-Sb-Te based devices. In particular, reversible set and reset switches by voltage pulses as short as 25 ns were demonstrated. The obtained results are useful for understanding the effects of downscaling in PCM devices and for the exploration of innovative PCM architectures and materials

    Cultural modulation of face and gaze scanning in young children

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    Previous research has demonstrated that the way human adults look at others’ faces is modulated by their cultural background, but very little is known about how such a culture-specific pattern of face gaze develops. The current study investigated the role of cultural background on the development of face scanning in young children between the ages of 1 and 7 years, and its modulation by the eye gaze direction of the face. British and Japanese participants’ eye movements were recorded while they observed faces moving their eyes towards or away from the participants. British children fixated more on the mouth whereas Japanese children fixated more on the eyes, replicating the results with adult participants. No cultural differences were observed in the differential responses to direct and averted gaze. The results suggest that different patterns of face scanning exist between different cultures from the first years of life, but differential scanning of direct and averted gaze associated with different cultural norms develop later in life

    In-doped Sb nanowires grown by MOCVD for high speed phase change memories

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    We investigated the Phase Change Memory (PCM) capabilities of In-doped Sb nanowires (NWs) with diameters of (20-40) nm, which were self-assembled by Metalorganic Chemical Vapor Deposition (MOCVD) via the vapor-liquid-solid (VLS) mechanism. The PCM behavior of the NWs was proved, and it was shown to have relatively low reset power consumption (~ 400 μW) and fast switching capabilities with respect to standard Ge-Sb-Te based devices. In particular, reversible set and reset switches by voltage pulses as short as 25 ns were demonstrated. The obtained results are useful for understanding the effects of downscaling in PCM devices and for the exploration of innovative PCM architectures and materials. Keywords: Phase change memories, Nanowires, MOCVD, In-Sb, TEM, XR

    The Ontology of Intentional Agency in Light of Neurobiological Determinism: Philosophy Meets Folk Psychology

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    The moot point of the Western philosophical rhetoric about free will consists in examining whether the claim of authorship to intentional, deliberative actions fits into or is undermined by a one-way causal framework of determinism. Philosophers who think that reconciliation between the two is possible are known as metaphysical compatibilists. However, there are philosophers populating the other end of the spectrum, known as the metaphysical libertarians, who maintain that claim to intentional agency cannot be sustained unless it is assumed that indeterministic causal processes pervade the action-implementation apparatus employed by the agent. The metaphysical libertarians differ among themselves on the question of whether the indeterministic causal relation exists between the series of intentional states and processes, both conscious and unconscious, and the action, making claim for what has come to be known as the event-causal view, or between the agent and the action, arguing that a sort of agent causation is at work. In this paper, I have tried to propose that certain features of both event-causal and agent-causal libertarian views need to be combined in order to provide a more defendable compatibilist account accommodating deliberative actions with deterministic causation. The ‘‘agent-executed-eventcausal libertarianism’’, the account of agency I have tried to develop here, integrates certain plausible features of the two competing accounts of libertarianism turning them into a consistent whole. I hope to show in the process that the integration of these two variants of libertarianism does not challenge what some accounts of metaphysical compatibilism propose—that there exists a broader deterministic relation between the web of mental and extra-mental components constituting the agent’s dispositional system—the agent’s beliefs, desires, short-term and long-term goals based on them, the acquired social, cultural and religious beliefs, the general and immediate and situational environment in which the agent is placed, etc. on the one hand and the decisions she makes over her lifetime on the basis of these factors. While in the ‘‘Introduction’’ the philosophically assumed anomaly between deterministic causation and the intentional act of deciding has been briefly surveyed, the second section is devoted to the task of bridging the gap between compatibilism and libertarianism. The next section of the paper turns to an analysis of folk-psychological concepts and intuitions about the effects of neurochemical processes and prior mental events on the freedom of making choices. How philosophical insights can be beneficially informed by taking into consideration folk-psychological intuitions has also been discussed, thus setting up the background for such analysis. It has been suggested in the end that support for the proposed theory of intentional agency can be found in the folk-psychological intuitions, when they are taken in the right perspective
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