2,712 research outputs found

    How do elderly pedestrians perceive hazards in the street? - An initial investigation towards development of a pedestrian simulation that incorporates reaction of various pedestrians to environments

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    In order to evaluate the accessibility of street and transport environments, such as railway stations, we are now developing a pedestrian simulation that incorporates elderly and disable pedestrians and their interaction with various environments including hazards on the street. For this development, it is necessary to understand how elderly and disabled pedestrians perceive hazards in the street and transport environments. Many elderly people suffer from some visual impairment. A study in the UK suggested 12% of people aged 65 or over have binocular acuity of 6/18 or less (Van der Pols et al, 2000). It should be noted that a quarter of the UK population will be aged 65 or over by 2031 (The Government Actuary's Department, 2004). Because of age-related changes of visual perception organs, elderly people suffer not only visual acuity problems but also other forms of visual disabilities, such as visual field loss and less contrast sensitivity. Lighting is considered to be an effective solution to let elderly and disable pedestrians perceive possible hazards in the street. Interestingly, British Standards for residential street lighting have not considered lighting needs of elderly pedestrians or pedestrians with visual disabilities (e.g. Fujiyama et al, 2005). In order to design street lighting that incorporates elderly and visually disabled pedestrians, it would be useful to understand how lighting improves the perception of hazards by elderly and disable pedestrians. The aim of this paper is to understand how elderly pedestrians perceive different hazards and to address issues to be investigated in future research. This paper focuses on fixation patterns of elderly pedestrians on different hazards in the street under different lighting conditions. Analysing fixation patterns helps us understand how pedestrians perceive environments or hazards (Fujiyama, 2006). This paper presents the initial results of our analysis of the eye tracker data of an ordinary elderly participant

    A high-Reynolds-number seal test facility: Facility description and preliminary test data

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    A facility has been developed for testing the leakage and rotordynamic characteristics of interstage-seal configurations for the HPFTP (High Pressure Fuel Turbopump) of the SSME (Space Shuttle Main Engine). Axial Reynolds numbers on the order of 400,000 are realized in the test facility by using a Dupont freon fluid called Halon (CBrF3). The kinematic viscosity of Halon is of the same order as the liquid hydrogen used in the HPFTP. Initial testing has focused on the current flight configurations (a three-segment, stepped unit) and a convergent-taper candidate

    Insight into the role of phosphatidylserine in complement-mediated synapse loss in Alzheimer's disease.

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    The innate immune system plays an integral role in the brain. Synaptic pruning, a fundamental process in developmental circuit refinement, is partially mediated by neuroimmune signalling at the synapse. In particular, microglia, the major tissue-resident macrophages of the brain, and the classical complement cascade, an innate immune pathway that aids in the clearance of unwanted material, have been implicated in mediating synapse elimination. Emerging data suggest that improper signalling of the innate immune pathway at the synapse leads to pathological synapse loss in age-related neurodegenerative diseases, including Alzheimer's disease. Now the key questions are whether synapses are targeted by complement and, if so, which synapses are vulnerable to elimination. Here, we review recent work implicating C1q, the initiator of the classical complement cascade, and surrounding glia as mediators of synapse loss. We examine how synapses could undergo apoptosis-like pathways in the Alzheimer brain, which may lead to the externalisation of phosphatidylserine on synapses. Finally, we discuss potential roles for microglia and astrocytes in this 'synaptic apoptosis'. Critical insight into neuroimmune regulatory pathways on synapses will be key to developing effective targets against pathological synapse loss in dementia

    GaAs-based Self-Aligned Stripe Superluminescent Diodes Processed Normal to the Cleaved Facet

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    We demonstrate GaAs-based superluminescent diodes (SLDs) incorporating a window-like back facet in a self-aligned stripe. SLDs are realised with low spectral modulation depth (SMD) at high power spectral density, without application of anti-reflection coatings. Such application of a window-like facet reduces effective facet reflectivity in a broadband manner. We demonstrate 30mW output power in a narrow bandwidth with only 5% SMD, outline the design criteria for high power and low SMD, and describe the deviation from a linear dependence of SMD on output power as a result of Joule heating in SLDs under continuous wave current injection. Furthermore, SLDs processed normal to the facet demonstrate output powers as high as 20mW, offering improvements in beam quality, ease of packaging and use of real estate. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

    Attributes Preferred and Premiums Offered for Naturally Produced Beef Cattle

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    A growing number of beef cattle producers in the US are using limited information to determine whether or not it would be economical for them to grow naturally produced cattle. The objective was to discover the attributes that marketing companies prefer for the naturally produced cattle they purchase, and to elicit the price premiums being offered for cattle that possess these attributes. Results of a phone survey of companies that purchase natural cattle show that 27 out of 32 companies report their willingness to pay a premium of $5.95/cwt for cattle that have never received antibiotics, ionophores, hormones or animal by-products.Key words: attributes, beef, cattle, naturally produced, premiums, Agribusiness, Food Consumption/Nutrition/Food Safety, Livestock Production/Industries, Marketing,

    The quantum to classical transition for random walks

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    We look at two possible routes to classical behavior for the discrete quantum random walk on the line: decoherence in the quantum ``coin'' which drives the walk, or the use of higher-dimensional coins to dilute the effects of interference. We use the position variance as an indicator of classical behavior, and find analytical expressions for this in the long-time limit; we see that the multicoin walk retains the ``quantum'' quadratic growth of the variance except in the limit of a new coin for every step, while the walk with decoherence exhibits ``classical'' linear growth of the variance even for weak decoherence.Comment: 4 pages RevTeX 4.0 + 2 figures (encapsulated Postscript). Trimmed for length. Minor corrections + one new referenc

    Flow Ambiguity: A Path Towards Classically Driven Blind Quantum Computation

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    Blind quantum computation protocols allow a user to delegate a computation to a remote quantum computer in such a way that the privacy of their computation is preserved, even from the device implementing the computation. To date, such protocols are only known for settings involving at least two quantum devices: either a user with some quantum capabilities and a remote quantum server or two or more entangled but noncommunicating servers. In this work, we take the first step towards the construction of a blind quantum computing protocol with a completely classical client and single quantum server. Specifically, we show how a classical client can exploit the ambiguity in the flow of information in measurement-based quantum computing to construct a protocol for hiding critical aspects of a computation delegated to a remote quantum computer. This ambiguity arises due to the fact that, for a fixed graph, there exist multiple choices of the input and output vertex sets that result in deterministic measurement patterns consistent with the same fixed total ordering of vertices. This allows a classical user, computing only measurement angles, to drive a measurement-based computation performed on a remote device while hiding critical aspects of the computation.Comment: (v3) 14 pages, 6 figures. expands introduction and definition of flow, corrects typos to increase readability; contains a new figure to illustrate example run of CDBQC protocol; minor changes to match the published version.(v2) 12 pages, 5 figures. Corrects motivation for quantities used in blindness analysi

    Facilitators and Barriers to Person-centred Care in Child and Young People Mental Health Services: A Systematic Review

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    Implementation of person-centred care has been widely advocated across various health settings and patient populations, including recent policy for child and family services. Nonetheless, evidence suggests that service users are rarely involved in decision-making, whilst their preferences and goals may be often unheard. The aim of the present research was to systematically review factors influencing person-centred care in mental health services for children, young people and families examining perspectives from professionals, service users and carers. This was conducted according to best practice guidelines, and seven academic databases were searched. Overall, 23 qualitative studies were included. Findings from the narrative synthesis of the facilitators and barriers are discussed in light of a recently published systematic review examining person-centred care in mental health services for adults. Facilitators and barriers were broadly similar across both settings. Training professionals in person-centred care, supporting them to use it flexibly to meet the unique needs of service users whilst also being responsive to times when it may be less appropriate and improving both the quantity and quality of information for service users and carers are key recommendations to facilitate person-centred care in mental health services with children, young people and families
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