86 research outputs found

    Projector - a partially typed language for querying XML

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    We describe Projector, a language that can be used to perform a mixture of typed and untyped computation against data represented in XML. For some problems, notably when the data is unstructured or semistructured, the most desirable programming model is against the tree structure underlying the document. When this tree structure has been used to model regular data structures, then these regular structures themselves are a more desirable programming model. The language Projector, described here in outline, gives both models within a single partially typed algebra and is well suited for hybrid applications, for example when fragments of a known structure are embedded in a document whose overall structure is unknown. Projector is an extension of ECMA-262 (aka JavaScript), and therefore inherits an untyped DOM interface. To this has been added some static typing and a dynamic projection primitive, which can be used to assert the presence of a regular structure modelled within the XML. If this structure does exist, the data is extracted and presented as a typed value within the programming language

    Evaluating rudimentary prehistoric stone artifacts from the American southwest and Mexico

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    The goals and background of this study are presented. A sample of rudimentary artifacts, recovered through survey and excavation from contexts in the American Southwest and southern Mexico, were physically examined to verify or reject their assumed validity as tools and their use in agricultural activities. Macroscopic and microscopic examinations were undertaken on these often overlooked and misidentified artifacts to ascertain evidence of human manufacture and use-wear. The results of the study indicate the specimens represent three general form categories of tools that have uses related to excavation and earth moving. To augment this evidence, information was gathered regarding find contexts, historic records, and from relevant literature. The geographic find locations and contexts of the artifacts, as well as their temporal placement, and likely group affiliations, are then discussed. Evidence indicates that, although probably used for other purposes, these minimally-retouched, hand-held, digging and earth moving tools were used in the preparation and maintenance of agricultural fields and irrigation canals, and functioned to support the subsistence system from ca. 400-1450 CE. These implements evidently also held social and ceremonial values and functions. The rudimentary nature of these tools is often found not to be commensurate with the sophisticated complexity of the associated agricultural infrastructure. Initial, very tentative, hypotheses are presented for this incongruity

    Aquilegia, Vol. 11 No. 1, January 1987: Newsletter of the Colorado Native Plant Society

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    The Colorado Native Plant Society Newsletter will be published on a bimonthly basis. The contents will consist primarily of a calendar of events, notes of interest, editorials, listings of new members and conservation news. Until there is a Society journal, the Newsletter will include short articles also. The deadline for the Newsletter is one month prior to its release.https://epublications.regis.edu/aquilegia/1032/thumbnail.jp

    Measuring Servitization Progress and Outcome:The Case of ‘Advanced Services’

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    The purpose of this paper is to establish a framework for assessing the progress and outcome of a manufacturer’s transformation towards becoming a provider of ‘advanced services’ – a complex bundling of products and services, whereby manufacturers offer capabilities and outcomes instead of products alone. ‘Advanced services’ represent the most complex offering in the current servitization trend among manufacturers. However, current performance measures lack the breadth and focus to assess progress or outcomes, and so support research and practice of organisational transformation efforts required. To address this gap the paper investigates how a manufacturer’s efforts to become an ‘advanced services’ provider can be comprehensively measured, and develops a framework for assessing the transformation journey towards becoming an ‘advanced services’ provider. The research method is based on (1) a systematic literature review process to create a comprehensive set of service-related performance measures that are available to assess a manufacturer’s servitization efforts, followed by (2) an engagement with an expert panel to synthesise the identified measures and create a set of ‘advanced services’ performance measures. The proposed framework is presented as a scorecard that can be used in practice to assess the progress and outcome of a manufacturer’s transformation towards becoming a provider of ‘advanced services’

    Radiation pressure-driven plasma surface dynamics in ultra-intense laser pulse interactions with ultra-thin foils

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    The dynamics of the plasma critical density surface in an ultra-thin foil target irradiated by an ultra-intense ( ∼ 6 × 1020 Wcm−2 ) laser pulse is investigated experimentally and via 2D particle-in- cell simulations. Changes to the surface motion are diagnosed as a function of foil thickness. The experimental and numerical results are compared with hole-boring and light-sail models of radi- ation pressure acceleration, to identify the foil thickness range for which each model accounts for the measured surface motion. Both the experimental and numerical results show that the onset of relativistic self-induced transparency, in the thinnest targets investigated, limits the velocity of the critical surface, and thus the e ff ectiveness of radiation pressure acceleration

    Influence of laser polarization on collective electron dynamics in ultraintense laser-foil interactions

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    The collective response of electrons in an ultrathin foil target irradiated by an ultraintense laser pulse is investigated experimentally and via 3D particle-in-cell simulations. It is shown that if the target is sufficiently thin that the laser induces significant radiation pressure, but not thin enough to become relativistically transparent to the laser light, the resulting relativistic electron beam is elliptical, with the major axis of the ellipse directed along the laser polarization axis. When the target thickness is decreased such that it becomes relativistically transparent early in the interaction with the laser pulse, diffraction of the transmitted laser light occurs through a so called 'relativistic plasma aperture', inducing structure in the spatial-intensity profile of the beam of energetic electrons. It is shown that the electron beam profile can be modified by variation of the target thickness and degree of ellipticity in the laser polarization

    Towards optical polarization control of laser-driven proton acceleration in foils undergoing relativistic transparency

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    Control of the collective response of plasma particles to intense laser light is intrinsic to relativistic optics, the development of compact laser-driven particle and radiation sources, as well as investigations of some laboratory astrophysics phenomena. We recently demonstrated that a relativistic plasma aperture produced in an ultra-thin foil at the focus of intense laser radiation can induce diffraction, enabling polarization-based control of the collective motion of plasma electrons. Here we show that under these conditions the electron dynamics are mapped into the beam of protons accelerated via strong charge-separation-induced electrostatic fields. It is demonstrated experimentally and numerically via 3D particle-in-cell simulations that the degree of ellipticity of the laser polarization strongly influences the spatial-intensity distribution of the beam of multi-MeV protons. The influence on both sheath accelerated and radiation pressure accelerated protons is investigated. This approach opens up new routes to control laser-driven ion sources

    A history of high-power laser research and development in the United Kingdom

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    The first demonstration of laser action in ruby was made in 1960 by T. H. Maiman of Hughes Research Laboratories, USA. Many laboratories worldwide began the search for lasers using different materials, operating at different wavelengths. In the UK, academia, industry and the central laboratories took up the challenge from the earliest days to develop these systems for a broad range of applications. This historical review looks at the contribution the UK has made to the advancement of the technology, the development of systems and components and their exploitation over the last 60 years

    Vitamin A and Retinoid Derivatives for Lung Cancer: A Systematic Review and Meta Analysis

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    Despite reported antiproliferative activity of vitamin A and its common use for cancer, there is no comprehensive synthesis of its safety and efficacy in lung cancers. To address this issue we conducted a systematic review of the safety and efficacy of vitamin A for the treatment and prevention of lung cancers.Two independent reviewers searched six electronic databases from inception to July 2009 for clinical, observational, and preclinical evidence pertaining to the safety and efficacy of vitamin A and related retinoids for lung cancers. 248 studies were included for full review and analysis. Five RCTs assessed treatment of lung cancers, three assessed primary prevention, and three looked at secondary prevention of lung cancers. Five surrogate studies, 26 phase I/II, 32 observational, and 67 preclinical studies were also included. 107 studies were included for interactions between vitamin A and chemo- or radiation-therapy. Although some studies demonstrated benefits, there was insufficient evidence overall to support the use of vitamin A or related retinoids for the treatment or prevention of lung cancers. Retinyl palmitate combined with beta carotene increased risk of lung cancer in smokers in the large CARET trial. Pooling of three studies pertaining to treatment and three studies on secondary prevention revealed no significant effects on response rate, second primary tumor, recurrence, 5-year survival, and mortality. There was a small improvement in event free survival associated with vitamin A compared to controls, RR 1.24 (95% CI 1.13-1.35). The synthetic rexinoid bexarotene increased survival significantly among a subset of patients in two RCTs (p<0.014, <0.087).There is a lack of evidence to support the use of naturally occurring retinoids for the treatment and prevention of lung cancers. The rexinoid bexarotene may hold promise for use among a subset of patients, and deserves further study

    Improving the efficiency and effectiveness of an industrial SARS-CoV-2 diagnostic facility.

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    On 11th March 2020, the UK government announced plans for the scaling of COVID-19 testing, and on 27th March 2020 it was announced that a new alliance of private sector and academic collaborative laboratories were being created to generate the testing capacity required. The Cambridge COVID-19 Testing Centre (CCTC) was established during April 2020 through collaboration between AstraZeneca, GlaxoSmithKline, and the University of Cambridge, with Charles River Laboratories joining the collaboration at the end of July 2020. The CCTC lab operation focussed on the optimised use of automation, introduction of novel technologies and process modelling to enable a testing capacity of 22,000 tests per day. Here we describe the optimisation of the laboratory process through the continued exploitation of internal performance metrics, while introducing new technologies including the Heat Inactivation of clinical samples upon receipt into the laboratory and a Direct to PCR protocol that removed the requirement for the RNA extraction step. We anticipate that these methods will have value in driving continued efficiency and effectiveness within all large scale viral diagnostic testing laboratories
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