3,966 research outputs found
A PC parallel port button box provides millisecond response time accuracy under Linux
No full textFor psychologists, it is sometimes necessary to measure people's reaction times to the nearest millisecond. This article describes how to use the PC parallel port to receive signals from a button box to achieve millisecond response time accuracy. The workings of the parallel port, the corresponding port addresses, and a simple Linux program for controlling the port are described. A test of the speed and reliability of button box signal detection is reported. If the reader is moderately familiar with Linux, this article should provide sufficient instruction for him or her to build and test his or her own parallel port button box. This article also describes how the parallel port could be used to control an external apparatus
Millisecond accuracy video display using OpenGL under Linux
No full textTo measure people’s reaction times to the nearest millisecond, it is necessary to know exactly when
a stimulus is displayed. This article describes how to display stimuli with millisecond accuracy on a
normal CRT monitor, using a PC running Linux. A simple C program is presented to illustrate how this
may be done within X Windows using the OpenGL rendering system. A test of this system is reported
that demonstrates that stimuli may be consistently displayed with millisecond accuracy. An algorithm
is presented that allows the exact time of stimulus presentation to be deduced, even if there are relatively
large errors in measuring the display time
Frontmatter (Titlepage, Table of Contents, Author List, PC List, Reviewer List)
No full textFront matter including table of contents, author list, PC list, and reviewer list
High efficiency implementation of PC and PC stable algorithms yields three-dimensional graphs of information flow for the Earth' atmosphere
No full textSeptember 3, 2014.Causal discovery algorithms have recently been applied to several climate applications. In particular, in prior work we have developed methods to recover pathways of interaction in the global climate system, using the classic PC algorithm. However, standard implementations of the PC algorithm cannot handle the large number of variables and temporal models required for this application. This technical report shows that a more efficient implementation of the PC algorithm can provide speed gains of a factor of 1,000 or more. This in turn enables us to calculate graphs of information flow with much higher resolution grids. Furthermore, we can now - for the first time ever - calculate information flow graphs that extend over three dimensions, i.e. rather than just including one layer of the planet's atmosphere we can now capture interactions across several height layers
Estudo dos níveis de referência de diagnóstico para procedimentos de tomografia computadorizada no estado de Santa Catarina
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde, Programa de Pós-Graduação em Ciências Médicas, Florianópolis, 2014.A Radiação Ionizante (RI) é conhecida por causar danos aos tecidos humanos e seu uso é cada vez mais frequente. Nesse âmbito, a Tomografia Computadorizada (TC) se destaca por ser responsável por mais de 40% da dose de radiação coletiva mundial. Uma das maneiras conhecidas utilizadas para monitorar e indicar a boa prática do uso da RI na TC, por sua vez, são os Níveis de Referência em Diagnóstico (DRL). Com base nesse panorama, o presente estudo tem por objetivo conhecer os níveis de dose praticados em TC no Estado de Santa Catarina - Brasil e, a partir de tais valores, propor DRLs para os exames de tomografia de crânio, tórax, abdômen e pelve, comparando-os com valores publicados na literatura internacional. Para tanto, foram analisados 1050 exames de Crânio, 108 de Tórax, 98 de Abdômen e 98 de Pelve, totalizando 1354 exames, cedidos por 11 instituições ou aparelhos de TC das seis regiões geográficas de Santa Catarina. A aquisição de valores das variáveis CTDIvol (mGy), Produto Dose-Comprimento (mGy.cm) e Corrente Efetiva (mAs) se deu de duas formas: extração da informação escrita do arquivo DICOM utilizando software específico, ou por meio do Relatório de Dose, em forma de imagem. Uma quarta informação, o Comprimento da Estrutura Irradiada, foi deduzida a partir do CTDIvol e do Produto Dose-Comprimento. Foram realizadas estatísticas descritivas (média, mediana, desvio-padrão, coeficiente de variação e 75 percentil ou terceiro quartil - Q¾) e testes estatísticos teste-t de Student e ANOVA com Post Hoc, por meio da correlação de Bonferroni, para a comparação de variáveis. O Q¾ aplicado ao CTDIvol e DLP foi de 57,4 mGy e 910,4 mGy.cm para exames de TC de crânio, 14,4 mGy e 395 mGy.cm para tórax, 16,25 mGy e 566,9 mGy.cm para abdômen, e 20 mGy e 410 mGy.cm para pelve, frente ao que se propôs novos DRLs (CTDIvol e DLP): 60 mGy e 1000 mGy.cm para TC de crânio, 15 mGy e 400 mGy.cm para TC tórax, 15 mGy para TC de abdômen e 20 mGy com 450 mGy.cm para pelve. Como resultados secundários, estatisticamente, os equipamentos Siemens, os aparelhos de dois canais e a região sul do Estado apresentaram menores doses de radiação ionizante (pAbstract : The Ionizing Radiation (IR) is known to cause damage to human tissue and its use is becoming increasingly common. Computed tomography (CT) is responsible for over 40 % of the global collective dose of radiation. One of the known ways to monitor and indicate good practice in the use of IR in TC is the Diagnostic Reference Levels (DRL). This study aims to evaluate the dose levels in CT practiced in the State of Santa Catarina (SC) - Brazil, propose DRLs for CT scans of head, thorax, abdomen and pelvis, and compare them with values published in the literature in other countries. In this context, 1050 head, 108 Thorax, 98Abdomen and 98 of pelvis exams were analyzed, totaling 1352 scans. Eleven institutions and CT scanners from 5 geographic regions of Santa Catarina participated in this study. The acquisition of variables values of CTDIvol (mGy), Dose-Length Product (mGy.cm) and Effective Current (mAs) were obtained in two ways: written information extracted from DICOM files using a specific software or through Dose Report image form. A fourth information, the Length of Radiated Structure was deduced from the CTDIvol and Dose-Length Product. Descriptive statistics (mean, median, standard deviation, coefficient of variation and 75 percentile or third quartile - Q¾) and statistical tests such as Student's t test and ANOVA with Bonferroni post hoc testing was used. The Q¾ CTDIvol and DLP was 57.4 mGy and 910.4 mGy.cm for CT of the Head, 14.4 mGy and 395 mGy.cm for chest, 16.25 mGy and 566.9 mGy.cm for abdomen and 20 mGy and 410 mGy.cm for pelvis. Thus the DRLs (CTDIvol and DLP ) were proposed: 60 mGy and 1000 mGy for head CT, 15 mGy and 400 mGy.cm for chest CT, 15 mGy for CT of the abdomen and 20 mGy and 450 mGy.cm for pelvis. As a secondary data, statistically the Siemens equipment, TC with 2 channel and southern Region of Santa Catarina have lower radiation doses (p<0.001). In an overview of the practiced exams of CT, SC it is in accordance with what is practiced in the countries compared in this study such as France and Ireland, standing up only in a few studies like the Maltese one. There is great potential for dose reduction as approximately half of the equipment produces smaller doses of radiation than that Q¾ doses obtained in this study
State variable simulation package for IBM-PC
No full textThis thesis was scanned from the print manuscript for digital preservation and is copyright the author.
Researchers can access this thesis by asking their local university, institution or public library to
make a request on their behalf. Monash staff and postgraduate students can use the link in the References field
Degradation of bisphenol-a-polycarbonate (BPA-PC) optical lenses under simulated harsh environment conditions
No full textThis paper investigates degradation and failure mechanisms of BPA-PC lenses in simulated harsh environment conditions. Exposure of secondary optics in Light Emitting Diode LED-based systems or any other similar applications to environmental stresses can adversely effect the performance and lifetime of products. This paper simulates a harsh environment condition, using a salt bath oven. Salt spray exposure/ageing tests at 45° C were carried out up to four months. Fourier transform infrared-attenuated total reflection FTIR-ATR spectrometer and Lambda 950 Ultraviolet-Visible (UV-VIS) spectrophotometer were used to study the optical and chemical characteristics of aged plates. Results showed that salt bath exposure test resulted in the severe deterioration of optical characteristics BPA-PC samples. Degradation of optical properties of BPA-PC plates is attributable to the oxidation of samples.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic Components, Technology and Material
Heavy pentaquark states Pc(4380) and Pc(4450) in the J/ψ production induced by pion beams off the nucleon
No full textAbstractIn this study, we investigate the J/ψ production induced by pion beams off the nucleon, particularly the heavy pentaquarks Pc(4380) and Pc(4450) in intermediate states, based on a hybridized Regge model. The process involving ρ and π meson exchange in the t channel is considered as background, and the heavy pentaquark exchange is included in the s channel. The coupling constants such as the ρNN and πNN vertices are taken from the NN potentials, whereas those for the J/ψρπ and J/ψππ vertices are determined by using experimental data based on the branching ratios. In order to estimate the Pc(4380) and Pc(4450) coupling constants, we use the experimental upper limit on the total cross section as a guide for the πN→J/ψN reaction. The background total cross section is the order of 10−4–10−3 nb. In the vicinity of the heavy pentaquark masses, the total cross section reaches about 1 nb
Data Assimilation for Full 4D PC-MRI Measurements: Physics-Based Denoising and Interpolation
No full textPhase-Contrast Magnetic Resonance Imaging (PC-MRI) surpasses all other imaging methods in quality and completeness for measuring time-varying volumetric blood flows and has shown potential to improve both diagnosis and risk assessment of cardiovascular diseases. However, like any measurement of physical phenomena, the data are prone to noise, artefacts and has a limited resolution. Therefore, PC-MRI data itself do not fulfil physics fluid laws making it difficult to distinguish important flow features. For data analysis, physically plausible and high-resolution data are required. Computational fluid dynamics provides high-resolution physically plausible flows. However, the flow is inherently coupled to the underlying anatomy and boundary conditions, which are difficult or sometimes even impossible to adequately model with current techniques. We present a novel methodology using data assimilation techniques for PC-MRI noise and artefact removal, generating physically plausible flow close to the measured data. It also allows us to increase the spatial and temporal resolution. To avoid sensitivity to the anatomical model, we consider and update the full 3D velocity field. We demonstrate our approach using phantom data with various amounts of induced noise and show that we can improve the data while preserving important flow features, without the need of a highly detailed model of the anatomy.Computer Graphics and Visualisatio
Cardiac sympathetic neurons provide trophic signal to the heart via β2- adrenoceptor dependent regulation of proteolysis.
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