337 research outputs found

    Maunakea Spectroscopic Explorer (MSE) - The Prime Focus Subsystems: Requirements and Interfaces

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    MSE will be a massively multiplexed survey telescope, including a segmented primary mirror which feeds fibers at the prime focus, including an array of approximately four thousand fibers, positioned precisely to feed banks of spectrographs several tens of meters away. We describe the process of mapping top-level requirements on MSE to technical specifications for subsystems located at the MSE prime focus. This includes the overall top-level requirements based on knowledge of similar systems at other telescopes and how those requirements were converted into specifications so that the subsystems could begin working on their Conceptual Design Phases. We then discuss the verification of the engineering specifications and the compiling of lower-level requirements and specifications into higher level performance budgets (e.g. Image Quality). We also briefly discuss the interface specifications, their effect on the performance of the system and the plan to manage them going forward. We also discuss the opto-mechanical design of the telescope top end assembly and refer readers to more details for instrumentation located at the top end.Comment: 14 pages; Proceedings of SPIE Astronomical Telescopes + Instrumentation 2018; Modeling, Systems Engineering, and Project Management for Astronomy VII

    A Comparison of the NZTM and FPS Models of the New Zealand Economy

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    This paper investigates and compares the dynamic properties of the New Zealand Treasury model (NZTM) and the current version of the Reserve Bank’s Forecasting and Policy System model (FPS). The main use of both two models is to produce macroeconomic forecasts. The NZTM model produces forecasts that are used as an input into the final forecast numbers presented in the Economic and Fiscal Updates. The FPS model is used to produce the published forecasts in the Reserve Bank’s quarterly Monetary Policy Statement. Both models contain a number of judgements around the structure of the economy, the key shocks that impact on the economy, and how the economy evolves in response to these shocks. The paper concludes that one of the main differences between the two models occurs in the impact of a world price shock on the real exchange rate and subsequently on exports and imports. Another key difference is the mechanism through which the net foreign asset position returns towards equilibrium. In FPS, the external balance is partly attained by forward-looking consumers who adjust spending to reach desired wealth positions. In contrast, the real exchange rate is the key mechanism in NZTM for re-establishing equilibrium.New Zealand; NZTM; FPS; Macroeconomic forecasts; Net foreign asset position; forwarding-looking consumers; Real exchange rate

    The Evidence for the Economic Value of eHealth in the United States Today: A Systematic Review

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    The United States healthcare system continues to face increasing costs, with year-over-year projected cost increases that now exceed the rate of increase of the gross domestic product. The rapid expansion and integration of eHealth within the United States healthcare system is driven primarily by a perceived ability to increase access in a cost-efficient manner. However, there is little economic research that addresses the large diversity of eHealth products being integrated into this healthcare landscape. The goal of this study is to evaluate the published economic evidence for eHealth in the United States, analyse how well it supports the growth of the current eHealth environment, and suggest what evidence is needed. This systematic literature review, conducted through the PubMed and The Cochrane Library databases, found that few studies addressed today’s eHealth environment. The current landscape is broader and less tailored to the traditional telemedicine initiatives represented by existing studies. We suggest more rigour in the design and scope of economic studies and that current eHealth technologies be identified for analysis. These studies must be comprehensive from the healthcare system’s perspective and conducted for relevant initiatives and patient groups to allow for evidence-based discussions on the cost-effectiveness of eHealth

    A method to assess demand growth vulnerability of travel times on road network links

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    Many national governments around the world have turned their recent focus to monitoring the actual reliability of their road networks. In parallel there have been major research efforts aimed at developing modelling approaches for predicting the potential vulnerability of such networks, and in forecasting the future impact of any mitigating actions. In practice-whether monitoring the past or planning for the future-a confounding factor may arise, namely the potential for systematic growth in demand over a period of years. As this growth occurs the networks will operate in a regime closer to capacity, in which they are more sensitive to any variation in flow or capacity. Such growth will be partially an explanation for trends observed in historic data, and it will have an impact in forecasting too, where we can interpret this as implying that the networks are vulnerable to demand growth. This fact is not reflected in current vulnerability methods which focus almost exclusively on vulnerability to loss in capacity. In the paper, a simple, moment-based method is developed to separate out this effect of demand growth on the distribution of travel times on a network link, the aim being to develop a simple, tractable, analytic method for medium-term planning applications. Thus the impact of demand growth on the mean, variance and skewness in travel times may be isolated. For given critical changes in these summary measures, we are thus able to identify what (location-specific) level of demand growth would cause these critical values to be exceeded, and this level is referred to as Demand Growth Reliability Vulnerability (DGRV). Computing the DGRV index for each link of a network also allows the planner to identify the most vulnerable locations, in terms of their ability to accommodate growth in demand. Numerical examples are used to illustrate the principles and computation of the DGRV measure

    (5,5′-Dimethyl-2,2′-bipyridine)­iodido­trimethyl­platinum(IV)

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    In the title compound, [Pt(CH3)3I(C12H12N2)], the PtIV atom is six-coordinated in a slightly distorted octa­hedral configuration with one CH3 group and the I atom forming a near perpendicular axis relative to the square plane formed by the bipyridine ligand and the two remaining CH3 groups. The CH3 group trans to the I atom has a slightly elongated bond to Pt compared to the other CH3 groups, indicating a difference in trans influence between iodine and the bipyridine ligand

    Dynamic traffic assignment approximating the kinematic wave model: system optimum, marginal costs, externalities and tolls

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    System marginal costs, externalities and optimal congestion tolls for traffic networks are generally derived from system optimizing (SO) traffic assignment models and when these are treated as varying over time they are all referred to as dynamic. In dynamic SO network models the link flows and travel times or costs are generally modelled using so-called ‘whole link’ models. Here we instead develop an SO model that more closely reflects traffic flow theory and derive the marginal costs and externalities from that. The most widely accepted traffic flow model appears to be the LWR (Lighthill, Whitham and Richards) model and a tractable discrete implementation or approximation to that is provided by the cell transmission model (CTM) or a finite difference approximation (FDA). These handles spillbacks, traffic controls and moving queues in a way that is consistent with the LWR model (hence with the kinematic wave model and fluid flow model). An SO formulation using the CTM is already available, assuming a single destination and a trapezoidal flow-density function. We extend the formulation to allow more general nonlinear flow density functions and derive and interpret system marginal costs and externalities. We show that if tolls computed from the DSO solution are imposed on users then the DSO solution would also satisfy the criteria for a dynamic user equilibrium (DUE). We introduce constraints on the link outflow proportions at merges and inflow proportions at diverges. We also extend the model to elastic demands and establish links with previous dynamic traffic assignment (DTA) models

    Lineage-Restricted OLIG2-RTK Signaling Governs the Molecular Subtype of Glioma Stem-like Cells

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    SummaryThe basic helix-loop-helix (bHLH) transcription factor OLIG2 is a master regulator of oligodendroglial fate decisions and tumorigenic competence of glioma stem-like cells (GSCs). However, the molecular mechanisms underlying dysregulation of OLIG2 function during gliomagenesis remains poorly understood. Here, we show that OLIG2 modulates growth factor signaling in two distinct populations of GSCs, characterized by expression of either the epidermal growth factor receptor (EGFR) or platelet-derived growth factor receptor alpha (PDGFRα). Biochemical analyses of OLIG2 function in normal and malignant neural progenitors reveal a positive feedforward loop between OLIG2 and EGFR to sustain co-expression. Furthermore, loss of OLIG2 function results in mesenchymal transformation in PDGFRαHIGH GSCs, a phenomenon that appears to be circumscribed in EGFRHIGH GSCs. Exploitation of OLIG2′s dual and antithetical, pro-mitotic (EGFR-driven), and lineage-specifying (PDGFRα-driven) functions by glioma cells appears to be critical for sustaining growth factor signaling and GSC molecular subtype

    NFIRAOS First Facility AO System for the Thirty Meter Telescope

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    NFIRAOS, the Thirty Meter Telescope's first adaptive optics system is an order 60x60 Multi-Conjugate AO system with two deformable mirrors. Although most observing will use 6 laser guide stars, it also has an NGS-only mode. Uniquely, NFIRAOS is cooled to -30 C to reduce thermal background. NFIRAOS delivers a 2-arcminute beam to three client instruments, and relies on up to three IR WFSs in each instrument. We present recent work including: robust automated acquisition on these IR WFSs; trade-off studies for a common-size of deformable mirror; real-time computing architectures; simplified designs for high-order NGS-mode wavefront sensing; modest upgrade concepts for high-contrast imaging.Comment: ..submitted to SPIE 9148 Astronomical Telescopes and Instrumentation - Adaptive Optics Systems IV (2014

    A Pilot Study Comparing HPV-Positive and HPV-Negative Head and Neck Squamous Cell Carcinomas by Whole Exome Sequencing.

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    Background. Next-generation sequencing of cancers has identified important therapeutic targets and biomarkers. The goal of this pilot study was to compare the genetic changes in a human papillomavirus- (HPV-)positive and an HPV-negative head and neck tumor. Methods. DNA was extracted from the blood and primary tumor of a patient with an HPV-positive tonsillar cancer and those of a patient with an HPV-negative oral tongue tumor. Exome enrichment was performed using the Agilent SureSelect All Exon Kit, followed by sequencing on the ABI SOLiD platform. Results. Exome sequencing revealed slightly more mutations in the HPV-negative tumor (73) in contrast to the HPV-positive tumor (58). Multiple mutations were noted in zinc finger genes (ZNF3, 10, 229, 470, 543, 616, 664, 638, 716, and 799) and mucin genes (MUC4, 6, 12, and 16). Mutations were noted in MUC12 in both tumors. Conclusions. HPV-positive HNSCC is distinct from HPV-negative disease in terms of evidence of viral infection, p16 status, and frequency of mutations. Next-generation sequencing has the potential to identify novel therapeutic targets and biomarkers in HNSCC
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