1,102 research outputs found
Reverse Carleson Embeddings for Model Spaces
The classical embedding theorem of Carleson deals with finite positive Borel
measures on the closed unit disk for which there exists a positive
constant such that for all ,
the Hardy space of the unit disk. Lef\'evre et al. examined measures for
which there exists a positive constant such that for all . The first type of inequality above was explored
with replaced by one of the model spaces by
Aleksandrov, Baranov, Cohn, Treil, and Volberg. In this paper we discuss the
second type of inequality in .Comment: 33 page
Delivery System Reform Tracking: A Framework for Understanding Change
Proposes a framework for tracking progress on delivery system reforms such as patient-centered medical homes and accountable care organizations by assessing structures, capabilities, incentives, and outcomes. Outlines challenges for data collection
Representation in Systems Development and Implementation: A Healthcare Enterprise System Implementation
Today’s information systems are often large and complex, affecting many people within and beyond the organization. Participation in this context is increasingly challenging because of the complexity of involving all who might be affected by a new information system. As a result, systems of representation, in which individuals are chosen to represent others, are often put in place to manage the participation process.
Research has considered particular challenges of “representative participation” (Mumford, 1983); however, there is little empirical research comprehensively examining these systems of representation. Who participates in these systems, how are they structured and how is this representative work undertaken? Most importantly, what are the impacts of these decisions on the representation systems that are built and on the participation that flows from them?
The purpose of our research is to explore the structuring of systems of representation in IS development and implementation. Building on the work of Land and Hirschheim (1983) and Mumford (1983), and drawing on Habermas’ deliberative democracy (1998), this research explores the system of representation employed in a large Electronic Health Record implementation as empirical evidence. Healthcare is a critical context for studying information systems implementation because of its uniqueness and complexity (Chiasson and Davidson, 2004; LeRouge et al., 2007), and therefore serves as an important environment for this research.
Our contributions, drawn from this Electronic Health Record project, include an understanding of three fundamental tasks for developing systems of representation: defining the constituency, selecting representatives, and determining how the representation relationship will be carried out. We demonstrate that systems of representation can be classified by different meanings of “represent.” These types – “represent as spokesperson,” “represent as example” and “represent as symbol” – differ in the purpose of representation, in who is involved and in how representation is undertaken. Most importantly, these types of systems differ in their participatory potential. The findings highlight the opportunities and challenges inherent in the construction and implementation of systems of representation.
The paper concludes by exploring the implications of these findings for practitioners and researchers, suggesting that representation should be more than simply appointing representatives, and offering mechanisms for participation and influence. We call on researchers to view these systems of representation in more fine-grained ways to better understand what their complexities mean for contemporary system development and implementation
Convergence of the Generalized Volume Averaging Method on a Convection-Diffusion Problem: A Spectral Perspective
A mixed formulation is proposed and analyzed mathematically for coupled convection-diffusion in heterogeneous medias. Transfer in solid parts driven by pure diffusion is coupled
with convection-diffusion transfer in fluid parts. This study is carried out for translation-invariant geometries (general infinite cylinders) and unidirectional flows. This formulation brings to the fore a new convection-diffusion operator, the properties of which are mathematically studied: its symmetry is first shown using a suitable scalar product. It is proved to be self-adjoint with compact
resolvent on a simple Hilbert space. Its spectrum is characterized as being composed of a double set of eigenvalues: one converging towards −∞ and the other towards +∞, thus resulting in a nonsectorial operator. The decomposition of the convection-diffusion problem into a generalized eigenvalue problem permits the reduction of the original three-dimensional problem into a two-dimensional one. Despite the operator being nonsectorial, a complete solution on the infinite cylinder, associated to a step change of the wall temperature at the origin, is exhibited with the help of the operator’s two sets of eigenvalues/eigenfunctions. On the computational point of view, a mixed variational formulation is naturally associated to the eigenvalue problem. Numerical illustrations are provided for axisymmetrical situations, the convergence of which is found to be consistent with the numerical discretization
Análisis y simulación de redes de dos puertos circuitos cuadripolos.
Este proyecto se basa en el estudio y simulación de los circuitos cuadripolos, los cuales se suelen denominar como una red o malla general que cuenta con dos pares de bornes, uno denominado “borne de entrada” y el otro “borne de salida”, estos circuitos son un bloque constitutivo muy importante de los sistemas electrónicos, ya sean estos de comunicación, de control automático, de transmisión y distribución u otros sistemas en los que la señal o la energía (ambas eléctricas) ingresan por los bornes de entrada, donde la red actúa sobre ellos y surge por bornes de salida.
El par de terminales o bornes de salida se deberían conectar perfectamente con el par de bornes de entrada de otra red. Cuando se estudia conceptos de las redes equivalentes de Thévenin y Norton, se exhibe la idea de que no siempre es necesario conocer las funciones detalladas de una parte de un circuito. Este tema amplía conceptos de este tipo a situaciones en las que incluso no se conocen los detalles de las funciones internas del circuito, suministrados solo con el conocimiento de que el circuito es lineal, y con la capacidad de medir tensiones y corrientes, se percibirá dentro de poco que es posible determinar las características de redes de esta clase con un grupo de parámetros que permitan predecir como interactuará la red con otras redes.This project is based on the study and simulation of quadrupole circuits, which are usually referred to as a network or general mesh that has two pair of terminals, one called “input terminal” and the other “terminal output”, these circuits are a very important constituent block of electronic systems, whether they are communication, automatic control, transmission and distribution or other systems in which the signal or energy (both electric) enter through the input terminals, where the network acts on them and emerges by output terminals.
The pair of terminals or output terminals should be perfectly connected to the input terminal pair of another network. When you study concepts from Thévenin and Norton´s equivalent networks, the idea is exhibited that it is not always necessary to know the detailed functions of a part of a circuit. This topic expands concepts of this type to situations in which the details of the internal functions of the circuit are not even know, provided only with the knowledge that the circuit is linear, and with the aptitude to measure tensions and currents, one will see soon that is possible to determine the characteristics of networks of this class with a set of parameters that it allows to predict since the network will interact with other networks
Direct and Reverse Carleson Measure for Hb spaces
In this paper we discuss direct and reverse Carleson measures for the de Branges-Rovnyak spaces H(b), mainly when b is a non-extreme point of the unit ball of H∞
Biological Markers of Auditory Gap Detection in Young, Middle-Aged, and Older Adults
The capability of processing rapid fluctuations in the temporal envelope of sound declines with age and this contributes to older adults' difficulties in understanding speech. Although, changes in central auditory processing during aging have been proposed as cause for communication deficits, an open question remains which stage of processing is mostly affected by age related changes. We investigated auditory temporal resolution in young, middle-aged, and older listeners with neuromagnetic evoked responses to gap stimuli with different leading marker and gap durations. Signal components specific for processing the physical details of sound stimuli as well as the auditory objects as a whole were derived from the evoked activity and served as biological markers for temporal processing at different cortical levels. Early oscillatory 40-Hz responses were elicited by the onsets of leading and lagging markers and indicated central registration of the gap with similar amplitude in all three age groups. High-gamma responses were predominantly related to the duration of no-gap stimuli or to the duration of gaps when present, and decreased in amplitude and phase locking with increasing age. Correspondingly, low-frequency activity around 200 ms and later was reduced in middle aged and older participants. High-gamma band, and long-latency low-frequency responses were interpreted as reflecting higher order processes related to the grouping of sound items into auditory objects and updating of memory for these objects. The observed effects indicate that age-related changes in auditory acuity have more to do with higher-order brain functions than previously thought
A Universal Action Formula
A universal formula for an action associated with a noncommutative geometry,
defined by a spectal triple (\Ac ,\Hc ,D), is proposed. It is based on the
spectrum of the Dirac operator and is a geometric invariant. The new symmetry
principle is the automorphism of the algebra \Ac which combines both
diffeomorphisms and internal symmetries. Applying this to the geometry defined
by the spectrum of the standard model gives an action that unifies gravity with
the standard model at a very high energy scale.Comment: This is a short non technical letter based on the longer version,
hep-th/9606001. Tex file, 10 page
Modelling the Epidemiological Impact of Intermittent Preventive Treatment against Malaria in Infants
BACKGROUND: Trials of intermittent preventive treatment against malaria in infants (IPTi) using sulphadoxine-pyrimethamine (SP) have shown a positive, albeit variable, protective efficacy against clinical malaria episodes. The impact of IPTi in different epidemiological settings and over time is unknown and predictions are hampered by the lack of knowledge about how IPTi works. We investigated mechanisms proposed for the action of IPTi and made predictions of the likely impact on morbidity and mortality. METHODS/PRINCIPAL FINDINGS: We used a comprehensive, individual-based, stochastic model of malaria epidemiology to simulate recently published trials of IPTi using SP with site-specific characteristics as inputs. This baseline model was then modified to represent hypotheses concerning the duration of action of SP, the temporal pattern of fevers caused by individual infections, potential benefits of avoiding fevers on immunity and the effect of sub-therapeutic levels of SP on parasite dynamics. The baseline model reproduced the pattern of results reasonably well. None of the models based on alternative hypotheses improved the fit between the model predictions and observed data. Predictions suggest that IPTi would have a beneficial effect across a range of transmission intensities. IPTi was predicted to avert a greater number of episodes where IPTi coverage was higher, the health system treatment coverage lower, and for drugs which were more efficacious and had longer prophylactic periods. The predicted cumulative benefits were proportionately slightly greater for severe malaria episodes and malaria-attributable mortality than for acute episodes in the settings modelled. Modest increased susceptibility was predicted between doses and following the last dose, but these were outweighed by the cumulative benefits. The impact on transmission intensity was negligible. CONCLUSIONS: The pattern of trial results can be accounted for by differences between the trial sites together with known features of malaria epidemiology and the action of SP. Predictions suggest that IPTi would have a beneficial impact across a variety of epidemiological settings
Evaluation of the WMO Solid Precipitation Intercomparison Experiment (SPICE) transfer functions for adjusting the wind bias in solid precipitation measurements
The World Meteorological Organization (WMO) Solid Precipitation Intercomparison Experiment (SPICE) involved extensive field intercomparisons of automated instruments for measuring snow during the 2013/2014 and 2014/2015 winter seasons. A key outcome of SPICE was the development of transfer functions for the wind bias adjustment of solid precipitation measurements using various precipitation gauge and wind shield configurations. Due to the short intercomparison period, the data set was not sufficiently large to develop and evaluate transfer functions using independent precipitation measurements, although on average the adjustments were effective at reducing the bias in unshielded gauges from −33.4 % to 1.1 %. The present analysis uses data collected at eight SPICE sites over the 2015/2016 and 2016/2017 winter periods, comparing 30 min adjusted and unadjusted measurements from Geonor T-200B3 and OTT Pluvio2 precipitation gauges in different shield configurations to the WMO Double Fence Automated Reference (DFAR) for the evaluation of the transfer function. Performance is assessed in terms of relative total catch (RTC), root mean square error (RMSE), Pearson correlation (r), and percentage of events (PEs) within 0.1 mm of the DFAR. Metrics are reported for combined precipitation types and for snow only. The evaluation shows that the performance varies substantially by site. Adjusted RTC varies from 54 % to 123 %, RMSE from 0.07 to 0.38 mm, r from 0.28 to 0.94, and PEs from 37 % to 84 %, depending on precipitation phase, site, and gauge configuration (gauge and wind screen type). Generally, windier sites, such as Haukeliseter (Norway) and Bratt's Lake (Canada), exhibit a net under-adjustment (RTC of 54 % to 83 %), while the less windy sites, such as Sodankylä (Finland) and Caribou Creek (Canada), exhibit a net over-adjustment (RTC of 102 % to 123 %). Although the application of transfer functions is necessary to mitigate wind bias in solid precipitation measurements, especially at windy sites and for unshielded gauges, the variability in the performance metrics among sites suggests that the functions be applied with caution
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