68,776 research outputs found

    It’s the Little Things that Count…

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    This paper will discuss the importance of detailed design decisions in the long term sustainability of any infrastructure system. It presents the concept of Universal Composition, first introduced by UCL’s new Universal Composition Laboratory (‘UCL-squared’) and emerging from the need to design in space and time for multiple senses towards the creation of more accessible, understandable and meaningful environments. It thus presents infrastructure design from the point of view of human perception, and argues the need to design for the senses in order to encourage sustainable behaviours concerning human mobility, transport and locational choice. After first explaining people-environment interactions, it discusses how the design of our urban infrastructure systems and environments can help stimulate our senses and thus behavioural change. Through two examples concerning bus stops implemented in London, it will explain how the role of both low and high tech technologies can help enhance interaction, improve accessibility and encourage usage. Thus, this paper aims to show that seemingly small details have a big role to play in the creation of infrastructure systems which enable, rather than inhibit, long term sustainable developmen

    Energy dependence of pion and kaon production in central Pb+Pb collisions

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    Measurements of charged pion and kaon production in central Pb+Pb collisions at 40, 80 and 158 AGeV are presented. These are compared with data at lower and higher energies as well as with results from p+p interactions. The mean pion multiplicity per wounded nucleon increases approximately linearly with s_NN^1/4 with a change of slope starting in the region 15-40 AGeV. The change from pion suppression with respect to p+p interactions, as observed at low collision energies, to pion enhancement at high energies occurs at about 40 AGeV. A non-monotonic energy dependence of the ratio of K^+ to pi^+ yields is observed, with a maximum close to 40 AGeV and an indication of a nearly constant value at higher energies.The measured dependences may be related to an increase of the entropy production and a decrease of the strangeness to entropy ratio in central Pb+Pb collisions in the low SPS energy range, which is consistent with the hypothesis that a transient state of deconfined matter is created above these energies. Other interpretations of the data are also discussed

    Trends and issues in the Medicaid 1915(c) waiver program.

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    Over the past 15 years, Medicaid 1915(c) home and community-based waivers have made a substantial contribution to States' efforts to transform their long-term care (LTC) systems from largely institutional to community-based systems. By 1997, every State had implemented a waiver program for at least some subgroups of individuals with disabilities, and expenditures increased from 3.8millionin1982tomorethan3.8 million in 1982 to more than 8.1 billion in 1997. Emerging, as well as long-standing, policy issues related to the waiver program include concerns with access, variation in availability by disability group, State decisions related to the provision of community-based LTC, and evidence on effectiveness

    Aspects of bovine caesarean section associated with calf mortality, dam survival and subsequent fertility.

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    Bovine caesarean section is a common surgery performed by cattle practitioners yet evidence for justifying many aspects of the surgical procedure is lacking. Between 2001 and 2007, questionnaires were used to gather information on 103 cases of caesarean section performed in one, predominantly dairy, veterinary practice. The results showed that the 14-day cow survival rate was 80.6%, and of those surviving beyond this period, 55.4% carried another calf to term, 27.7% were culled due to infertility and 16.9% were culled due to other reasons. Variables associated with reduced 14-day dam mortality included exteriorising the uterus during surgery (odds ratio [OR] 0.018, 95% confidence interval [CI] 0.0019-0.17, P<0.001), dystocia where fetomaternal disproportion was present (OR 0.090, 95% CI 0.097-0.83, P=0.033), a female calf (OR 0.036, 95% CI 0.0019-0.69, P=0.027), no retained fetal membranes at the first post-operative revisit (OR 0.095, 95% CI 0.013-0.69, P=0.020) and removing abdominal blood clots during surgery (OR 0.10, 95% CI 0.011-0.93, P=0.043). Using a Utrecht suture pattern on the uterus was associated with reduced culling due to infertility (OR 0.12, 95% CI 0.020-0.67, P=0.016). Incision infection was noted in 25.9% of cases where incision status was recorded but this was not associated with the type of local anaesthesia used. Overall calf survival up to the first post-operative visit (24-48 h) was 59.4%, and was associated with shorter duration of surgery, and dystocia due to fetomaternal disproportion. These results offer some evidence-based guidelines to optimise outcomes for this common surgery performed under field conditions

    Diquark Representations for Singly Heavy Baryons with Light Staggered Quarks

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    In the staggered fermion formulation of lattice QCD, we construct diquark operators which are to be embedded in singly heavy baryons. The group theoretical connections between continuum and lattice staggered diquark representations are established.Comment: v1, 13 pages with title "Staggered Diquarks for Singly Heavy Baryons"; v2, 4 pages in revtex, changed the title to be more specifi

    Can shared surfaces be safely negotiated by blind and partially sighted people?

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    ‘Shared Space’ schemes are designed to remove the physical distinction between pedestrian space and traffic space in the street environment to encourage more pedestrians to use the area. They may also make it easier for people with wheelchairs, prams or similar to negotiate the space. However, by removing the kerbs, blind and partially sighted people lose one of the key references that they normally use to know they are in a safe space away from vehicles and to navigate around the area. This study is intended to understand what people with visual impairments need from a surface to make it clearly detectable, given that it should not be a barrier to progress for people with other mobility limitations. With this information, some surfaces were tested to determine their suitability as a delineator. Approach and/or Methodology An experimental approach was adopted. People with mobility impairments and blind and partially sighted people were recruited. All participants used the normal street environment unaccompanied. The blind and partially sighted participants included people who use a guide dog, those who use a long cane and those who use no assistive device. The people with mobility impairments all used some form of mobility aid for example walking stick or wheelchair. The tests were run in the pedestrian testing facility PAMELA at UCL. The top surface of the test facility was predominantly concrete paving slab, but with test surfaces discretely located. The task for all participants was to travel from one designated place in the test area to another. For some of these trials the participant would encounter one of the test surfaces, but on other trials they would not. After each trial the participants were asked to rate how easy it was to detect a change in surface, or how easy it was to pass over the surface. The different surfaces included blister paving, corduroy paving, a central delineator, slopes, roughened surfaces, and traditional kerb upstands of different heights. Results or Expected Results None of the 400mm wide surfaces was detected by all participants. Changes in level through slopes were considered both positively and negatively, some people asking for steeper gradients and some less steep. Kerb heights below 60mm were not reliably detectable by blind or partially sighted people and are an obstacle to people in wheelchairs. Further tests on more surfaces are in process and the results will be incorporated into this paper. Conclusion Early suggestions for detectable surfaces – proposed in UK schemes - have been either a barrier to people with mobility impairments, or difficult to detect for blind and partially sighted people or both. The work presented in this paper shows the difficulty in finding a suitable dual purpose surface, yet clarifies the design requirements for shared space delineators for people with mobility impairments and blind or partially sighted people. This work has reinforced the point that 400mm width is insufficient to be used as a tactile surface. Further conclusions will be made after the additional surface tests. Topic Code: Ca C. Accessibility concerns and solutions for those with cognitive and sensory impairment a. Pedestrian safety at crossings and intersection

    Learning a local-variable model of aromatic and conjugated systems

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    A collection of new approaches to building and training neural networks, collectively referred to as deep learning, are attracting attention in theoretical chemistry. Several groups aim to replace computationally expensive <i>ab initio</i> quantum mechanics calculations with learned estimators. This raises questions about the representability of complex quantum chemical systems with neural networks. Can local-variable models efficiently approximate nonlocal quantum chemical features? Here, we find that convolutional architectures, those that only aggregate information locally, cannot efficiently represent aromaticity and conjugation in large systems. They cannot represent long-range nonlocality known to be important in quantum chemistry. This study uses aromatic and conjugated systems computed from molecule graphs, though reproducing quantum simulations is the ultimate goal. This task, by definition, is both computable and known to be important to chemistry. The failure of convolutional architectures on this focused task calls into question their use in modeling quantum mechanics. To remedy this heretofore unrecognized deficiency, we introduce a new architecture that propagates information back and forth in waves of nonlinear computation. This architecture is still a local-variable model, and it is both computationally and representationally efficient, processing molecules in sublinear time with far fewer parameters than convolutional networks. Wave-like propagation models aromatic and conjugated systems with high accuracy, and even models the impact of small structural changes on large molecules. This new architecture demonstrates that some nonlocal features of quantum chemistry can be efficiently represented in local variable models

    DK,lνD \rightarrow K, l \nu Semileptonic Decay Scalar Form Factor and Vcs|V_{cs}| from Lattice QCD

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    We present a new study of D semileptonic decays on the lattice which employs the Highly Improved Staggered Quark (HISQ) action for both the charm and the light valence quarks. We work with MILC unquenched Nf=2+1N_f = 2 + 1 lattices and determine the scalar form factor f0(q2)f_0(q^2) for DK,lνD \rightarrow K, l \nu semileptonic decays. The form factor is obtained from a scalar current matrix element that does not require any operator matching. We develop a new approach to carrying out chiral/continuum extrapolations of f0(q2)f_0(q^2). The method uses the kinematic "zz" variable instead of q2q^2 or the kaon energy EKE_K and is applicable over the entire physical q2q^2 range. We find f0DK(0)f+DK(0)=0.747(19)f^{D \rightarrow K}_0(0) \equiv f^{D \rightarrow K}_+(0) = 0.747(19) in the chiral plus continuum limit and hereby improve the theory error on this quantity by a factor of \sim4 compared to previous lattice determinations. Combining the new theory result with recent experimental measurements of the product f+DK(0)Vcsf^{D \rightarrow K}_+(0) * |V_{cs}| from BaBar and CLEO-c leads to the most precise direct determination of the CKM matrix element Vcs|V_{cs}| to date, Vcs=0.961(11)(24)|V_{cs}| = 0.961(11)(24), where the first error comes from experiment and the second is the lattice QCD theory error. We calculate the ratio f+DK(0)/fDsf^{D \rightarrow K}_+(0)/f_{D_s} and find 2.986±0.0872.986 \pm 0.087 GeV1^{-1} and show that this agrees with experiment.Comment: 23 pages, 31 figures, 11 tables. Added a paragraph in sction VII, and updated with PDG 2010 instead of PDG 200
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