4,691 research outputs found

    Haze in the Klang Valley of Malaysia

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    Continuous measurements of dry aerosol light scattering (Bsp) were made at two sites in the Klang Valley of Malaysia between December 1998 and December 2000. In addition 24-h PM2.5 samples were collected on a one-day-in-six cycle and the chemical composition of the aerosol was determined. Periods of excessive haze were defined as 24-h average Bsp values greater than 150 Mm-1 and these occurred on a number of occasions, between May and September 1999, during May 2000, and between July and September 2000. The evidence for smoke being a significant contributor to aerosol during periods of excessive haze is discussed and includes features of the aerosol chemistry, the diurnal cycle of Bsp, and the coincidence of forest fires on Sumatra during the southwest (SW) monsoon period, as well as transport modelling for one week of the southwest Monsoon of 2000. The study highlights that whilst transboundary smoke is a major contributor to poor visibility in the Klang Valley, smoke from fires on Peninsular Malaysia is also a contributor, and at all times, the domestic source of secondary particle production is present

    Repeat-Until-Success quantum computing using stationary and flying qubits

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    We introduce an architecture for robust and scalable quantum computation using both stationary qubits (e.g. single photon sources made out of trapped atoms, molecules, ions, quantum dots, or defect centers in solids) and flying qubits (e.g. photons). Our scheme solves some of the most pressing problems in existing non-hybrid proposals, which include the difficulty of scaling conventional stationary qubit approaches, and the lack of practical means for storing single photons in linear optics setups. We combine elements of two previous proposals for distributed quantum computing, namely the efficient photon-loss tolerant build up of cluster states by Barrett and Kok [Phys. Rev. A 71, 060310(R) (2005)] with the idea of Repeat-Until-Success (RUS) quantum computing by Lim et al. [Phys. Rev. Lett. 95, 030505 (2005)]. This idea can be used to perform eventually deterministic two-qubit logic gates on spatially separated stationary qubits via photon pair measurements. Under non-ideal conditions, where photon loss is a possibility, the resulting gates can still be used to build graph states for one-way quantum computing. In this paper, we describe the RUS method, present possible experimental realizations, and analyse the generation of graph states.Comment: 14 pages, 7 figures, minor changes, references and a discussion on the effect of photon dark counts adde

    The Impact of Parenting on First-Time Mothers Mental Health and Sense of Competence: A Mixed-Method Study

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    Early adverse childhood experiences impact the psychosocial functioning of individuals when they become parents themselves including links to postnatal mental health problems. Previous research primarily focused broadly on attachments styles or the impact of abuse on parenting. This mixed-method study will look at both negative and positive day-to-day parenting interactions that mothers experienced with their own parents. A community sample of 212 first time mothers of infants under 12-months old completed questionnaires relating to perceptions of being parented, parenting stress, parenting sense of competence, postnatal depression and postnatal anxiety. 25 of these mothers were then interviewed 1:1 to explore at a deeper level the transition to motherhood and aspects of their own parenting that they draw upon. Quantitative data was analysed using PROCESS for moderating and mediating relationships and qualitative data was analysed using reflexive thematic analysis. Results showed that both positive and negative experiences of being parented affect mothers’ sense of competence and that this relationship is mediated by mental health disorders such as depression and anxiety. Stress moderated some of these relationships. Reflexive thematic analysis generated themes explaining how mothers’ made sense of and responded to their own experiences of being parented in order to manage their own mental health and develop their own parenting styles. These findings have implications for postnatal mental health services and parenting programs

    Disruption of a Yeast ADE6 Gene Homolog in Ustilago maydis

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    A putative homolog of the Sacharromyces cereviseae ADE6 and Escherichia coli purL genes is identified near a multigenic complex, which contains two genes, sid1 and sid2, involved in a siderophore biosynthetic pathway inUstilago maydis. The putative ADE6 homolog was mutated by targeted gene disruption. The resulting mutant strains demonstrated a requirement for exogenous adenine, indicating that the U. maydis ade6 homolog is required for purine biosynthesis

    A millimeter-wave antireflection coating for cryogenic silicon lenses

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    We have developed and tested an antireflection (AR) coating method for silicon lenses at cryogenic temperatures and millimeter wavelengths. Our particular application is a measurement of the cosmic microwave background. The coating consists of machined pieces of Cirlex glued to the silicon. The measured reflection from an AR coated flat piece is less than 1.5% at the design wavelength. The coating has been applied to flats and lenses and has survived multiple thermal cycles from 300 to 4 K. We present the manufacturing method, the material properties, the tests performed, and estimates of the loss that can be achieved in practical lenses

    Extending Feynman's Formalisms for Modelling Human Joint Action Coordination

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    The recently developed Life-Space-Foam approach to goal-directed human action deals with individual actor dynamics. This paper applies the model to characterize the dynamics of co-action by two or more actors. This dynamics is modelled by: (i) a two-term joint action (including cognitive/motivatonal potential and kinetic energy), and (ii) its associated adaptive path integral, representing an infinite--dimensional neural network. Its feedback adaptation loop has been derived from Bernstein's concepts of sensory corrections loop in human motor control and Brooks' subsumption architectures in robotics. Potential applications of the proposed model in human--robot interaction research are discussed. Keywords: Psycho--physics, human joint action, path integralsComment: 6 pages, Late

    Hypoalbuminaemia and its association with disease and clinical outcomes in cats

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    Objectives: To report the incidence of feline hypoalbuminaemia and characterise the distribution of presenting disease categories and pathoaetiologies of hypoalbuminaemia in cats. The secondary aim was to evaluate the relationship between hypoalbuminaemia and clinical outcomes. Materials and Methods: Medical records of cats with hypoalbuminaemia (&lt;28.0 g/L, reference interval: 28.0 to 39.0 g/L) presenting to a veterinary teaching hospital over 5 years were retrospectively reviewed. The severity of hypoalbuminaemia was further stratified into mild (24.0 to 27.9 g/L), moderate (20.0 to 23.9 g/L) and severe (≤19.9 g/L) groups. The median albumin and severity groups were compared between the determined disease categories, pathoaetiologies and clinical outcomes. Results: The incidence of hypoalbuminaemia was 32.7% (533/1632). Gastrointestinal disease was the most common disease category associated with hypoalbuminaemia [154/533 (28.9%)], of which, 49.4% (76/154) of cats had gastrointestinal neoplasia. Neoplastic [159/533 (29.8%)] and inflammatory conditions [158/533 (29.6%)] were common pathoaetiologies noted. Statistically significant differences in the serum albumin between individual disease and pathoaetiological categories were found. Cats with moderate to severe hypoalbuminaemia had a statistically significantly longer hospitalisation period, cost of treatment and increased odds of death (odds ratio 2.4, 95% confidence interval: 1.3 to 4.6 and odds ratio 3.2, 95% confidence interval: 1.5 to 6.6, respectively). Clinical Significance: The incidence of feline hypoalbuminaemia in our study surpasses previous canine reports. Our findings support albumin as a negative acute phase protein in cats, with hypoalbuminaemia frequently associated with inflammatory disease. Hypoalbuminaemia also features prominently in cats with gastrointestinal neoplasia, indicating careful appraisal of the presence of protein-losing enteropathy is required in these cases. Finally, albumin is found to be a prognostic indicator in this study.</p

    Network governance for large‐scale natural resource conservation and the challenge of capture

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    Large‐scale natural resource conservation initiatives are increasingly adopting a network governance framework to respond to the ecological, social, and political challenges of contemporary environmental governance. A network approach offers new modes of management that allow resource managers and others to transcend a single institution, organization, resource, or landscape and engage in conservation that is multi‐species and multi‐jurisdictional. However, there are challenges to network governance in large‐scale conservation efforts, which we address by focusing on how special interests can capture networks and shape the goals, objectives, and outcomes of initiatives. The term “network capture” is used here to describe an array of strategies that direct the processes and outcomes of large‐scale initiatives in ways that advance a group\u27s positions, concerns, or economic interests. We outline how new stakeholders emerge from these management processes, and how the ease of information sharing can blur stakeholder positions and lead to competing knowledge claims. We conclude by reasserting the benefits of network governance while acknowledging the unique challenges that networks present

    An experimental observation of geometric phases for mixed states using NMR interferometry

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    Examples of geometric phases abound in many areas of physics. They offer both fundamental insights into many physical phenomena and lead to interesting practical implementations. One of them, as indicated recently, might be an inherently fault-tolerant quantum computation. This, however, requires to deal with geometric phases in the presence of noise and interactions between different physical subsystems. Despite the wealth of literature on the subject of geometric phases very little is known about this very important case. Here we report the first experimental study of geometric phases for mixed quantum states. We show how different they are from the well understood, noiseless, pure-state case.Comment: 4 pages, 3 figure
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