SU-E-T-33: A Feasibility-Seeking Algorithm Applied to Planning of Intensity Modulated Proton Therapy: A Proof of Principle Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Penfold, S; Casiraghi, M; Dou, T

2015-06-15

Purpose: To investigate the applicability of feasibility-seeking cyclic orthogonal projections to the field of intensity modulated proton therapy (IMPT) inverse planning. Feasibility of constraints only, as opposed to optimization of a merit function, is less demanding algorithmically and holds a promise of parallel computations capability with non-cyclic orthogonal projections algorithms such as string-averaging or block-iterative strategies. Methods: A virtual 2D geometry was designed containing a C-shaped planning target volume (PTV) surrounding an organ at risk (OAR). The geometry was pixelized into 1 mm pixels. Four beams containing a subset of proton pencil beams were simulated in Geant4 to provide themore » system matrix A whose elements a-ij correspond to the dose delivered to pixel i by a unit intensity pencil beam j. A cyclic orthogonal projections algorithm was applied with the goal of finding a pencil beam intensity distribution that would meet the following dose requirements: D-OAR < 54 Gy and 57 Gy < D-PTV < 64.2 Gy. The cyclic algorithm was based on the concept of orthogonal projections onto half-spaces according to the Agmon-Motzkin-Schoenberg algorithm, also known as ‘ART for inequalities’. Results: The cyclic orthogonal projections algorithm resulted in less than 5% of the PTV pixels and less than 1% of OAR pixels violating their dose constraints, respectively. Because of the abutting OAR-PTV geometry and the realistic modelling of the pencil beam penumbra, complete satisfaction of the dose objectives was not achieved, although this would be a clinically acceptable plan for a meningioma abutting the brainstem, for example. Conclusion: The cyclic orthogonal projections algorithm was demonstrated to be an effective tool for inverse IMPT planning in the 2D test geometry described. We plan to further develop this linear algorithm to be capable of incorporating dose-volume constraints into the feasibility-seeking algorithm.« less

Simple Pencil-and-Paper Notation for Representing Electrical Charge States

ERIC Educational Resources Information Center

Morse, Robert A.

2017-01-01

In Benjamin Franklin's one fluid theory of electrification, ordinary unelectrified matter consisted of a matrix of matter suffused with a certain amount of "electrical fluid." Electrical effects were due to an excess or deficit of electrical fluid, hence the terms positive and negative. Before the development of a modern view of the…

Spot-scanning beam delivery with laterally- and longitudinally-mixed spot size pencil beams in heavy ion radiotherapy

NASA Astrophysics Data System (ADS)

Yan, Yuan-Lin; Liu, Xin-Guo; Dai, Zhong-Ying; Ma, Yuan-Yuan; He, Peng-Bo; Shen, Guo-Sheng; Ji, Teng-Fei; Zhang, Hui; Li, Qiang

2017-09-01

The three-dimensional (3D) spot-scanning method is one of the most commonly used irradiation methods in charged particle beam radiotherapy. Generally, spot-scanning beam delivery utilizes the same size pencil beam to irradiate the tumor targets. Here we propose a spot-scanning beam delivery method with laterally- and longitudinally-mixed size pencil beams for heavy ion radiotherapy. This uses pencil beams with a bigger spot size in the lateral direction and wider mini spread-out Bragg peak (mini-SOBP) to irradiate the inner part of a target volume, and pencil beams with a smaller spot size in the lateral direction and narrower mini-SOBP to irradiate the peripheral part of the target volume. Instead of being controlled by the accelerator, the lateral size of the pencil beam was adjusted by inserting Ta scatterers in the beam delivery line. The longitudinal size of the pencil beam (i.e. the width of the mini-SOBP) was adjusted by tilting mini ridge filters along the beam direction. The new spot-scanning beam delivery using carbon ions was investigated theoretically and compared with traditional spot-scanning beam delivery. Our results show that the new spot-scanning beam delivery has smaller lateral penumbra, steeper distal dose fall-off and the dose homogeneity (1-standard deviation/mean) in the target volume is better than 95%. Supported by Key Project of National Natural Science Foundation of China (U1232207), National Key Technology Support Program of the Ministry of Science and Technology of China (2015BAI01B11), National Key Research and Development Program of the Ministry of Science and Technology of China (2016YFC0904602) and National Natural Science Foundation of China (11075191, 11205217, 11475231, 11505249)

{ital R}-matrix theory, formal Casimirs and the periodic Toda lattice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morosi, C.; Pizzocchero, L.

The nonunitary {ital r}-matrix theory and the associated bi- and triHamiltonian schemes are considered. The language of Poisson pencils and of their formal Casimirs is applied in this framework to characterize the biHamiltonian chains of integrals of motion, pointing out the role of the Schur polynomials in these constructions. This formalism is subsequently applied to the periodic Toda lattice. Some different algebraic settings and Lax formulations proposed in the literature for this system are analyzed in detail, and their full equivalence is exploited. In particular, the equivalence between the loop algebra approach and the method of differential-difference operators is illustrated;more » moreover, two alternative Lax formulations are considered, and appropriate reduction algorithms are found in both cases, allowing us to derive the multiHamiltonian formalism from {ital r}-matrix theory. The systems of integrals for the periodic Toda lattice known after Flaschka and H{acute e}non, and their functional relations, are recovered through systematic application of the previously outlined schemes. {copyright} {ital 1996 American Institute of Physics.}« less

Examination of the Equivalence of Self-Report Survey-Based Paper-and-Pencil and Internet Data Collection Methods

ERIC Educational Resources Information Center

Weigold, Arne; Weigold, Ingrid K.; Russell, Elizabeth J.

2013-01-01

Self-report survey-based data collection is increasingly carried out using the Internet, as opposed to the traditional paper-and-pencil method. However, previous research on the equivalence of these methods has yielded inconsistent findings. This may be due to methodological and statistical issues present in much of the literature, such as…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Igarashi, Noriyuki, E-mail: noriyuki.igarashi@kek.jp; Nitani, Hiroaki; Takeichi, Yasuo

BL-15A is a new x-ray undulator beamline at the Photon Factory. It will be dedicated to two independent research activities, simultaneous XAFS/XRF/XRD experiments, and SAXS/WAXS/GI-SAXS studies. In order to supply a choice of micro-focus, low-divergence and collimated beams, a double surface bimorph mirror was recently developed. To achieve further mirror surface optimization, the pencil beam scanning method was applied for “in-situ” beam inspection and the Inverse Matrix method was used for determination of optimal voltages on the piezoelectric actuators. The corrected beam profiles at every focal spot gave good agreement with the theoretical values and the resultant beam performance ismore » promising for both techniques. Quick and stable switching between highly focused and intense collimated beams was established using this new mirror with the simple motorized stages.« less

Propagation of Flexural Mode AE Signals in GR/EP Composite Plates

NASA Technical Reports Server (NTRS)

Prosser, W. H.; Gorman, M. R.

1992-01-01

It has been documented that AE signals propagate in thin plates as extensional and flexural plate modes. This was demonstrated using simulated AE sources (pencil lead breaks) by Gorman on thin aluminum and gr/ep composite plates and by Gorman and Prosser on thin aluminum plates. A typical signal from a pencil lead break source which identifies these two modes is shown. AE signals from transverse matrix cracking sources in gr/ep composite plates were also shown to propagate as plate modes by Gorman and Ziola. Smith showed that crack growth events in thin aluminum plates under spectrum fatigue loading produced signals that propagated as plate modes. Additionally, Prosser et al. showed that AE signals propagated as plate modes in a thin walled composite tube.

A comparative trial of paper-and-pencil versus computer administration of the Quality of Life in Reflux and Dyspepsia (QOLRAD) questionnaire.

PubMed

Kleinman, L; Leidy, N K; Crawley, J; Bonomi, A; Schoenfeld, P

2001-02-01

Although most health-related quality of life questionnaires are self-administered by means of paper and pencil, new technologies for automated computer administration are becoming more readily available. Novel methods of instrument administration must be assessed for score equivalence in addition to consistency in reliability and validity. The present study compared the psychometric characteristics (score equivalence and structure, internal consistency, and reproducibility reliability and construct validity) of the Quality of Life in Reflux And Dyspepsia (QOLRAD) questionnaire when self-administered by means of paper and pencil versus touch-screen computer. The influence of age, education, and prior experience with computers on score equivalence was also examined. This crossover trial randomized 134 patients with gastroesophageal reflux disease to 1 of 2 groups: paper-and-pencil questionnaire administration followed by computer administration or computer administration followed by use of paper and pencil. To minimize learning effects and respondent fatigue, administrations were scheduled 3 days apart. A random sample of 32 patients participated in a 1-week reproducibility evaluation of the computer-administered QOLRAD. QOLRAD scores were equivalent across the 2 methods of administration regardless of subject age, education, and prior computer use. Internal consistency levels were very high (alpha = 0.93-0.99). Interscale correlations were strong and generally consistent across methods (r = 0.7-0.87). Correlations between the QOLRAD and Short Form 36 (SF-36) were high, with no significant differences by method. Test-retest reliability of the computer-administered QOLRAD was also very high (ICC = 0.93-0.96). Results of the present study suggest that the QOLRAD is reliable and valid when self-administered by means of computer touch-screen or paper and pencil.

Using Patterns of Summed Scores in Paper-and-Pencil Tests and Computer-Adaptive Tests to Detect Misfitting Item Score Patterns

ERIC Educational Resources Information Center

Meijer, Rob R.

2004-01-01

Two new methods have been proposed to determine unexpected sum scores on sub-tests (testlets) both for paper-and-pencil tests and computer adaptive tests. A method based on a conservative bound using the hypergeometric distribution, denoted p, was compared with a method where the probability for each score combination was calculated using a…

Two-dimensional grid-free compressive beamforming.

PubMed

Yang, Yang; Chu, Zhigang; Xu, Zhongming; Ping, Guoli

2017-08-01

Compressive beamforming realizes the direction-of-arrival (DOA) estimation and strength quantification of acoustic sources by solving an underdetermined system of equations relating microphone pressures to a source distribution via compressive sensing. The conventional method assumes DOAs of sources to lie on a grid. Its performance degrades due to basis mismatch when the assumption is not satisfied. To overcome this limitation for the measurement with plane microphone arrays, a two-dimensional grid-free compressive beamforming is developed. First, a continuum based atomic norm minimization is defined to denoise the measured pressure and thus obtain the pressure from sources. Next, a positive semidefinite programming is formulated to approximate the atomic norm minimization. Subsequently, a reasonably fast algorithm based on alternating direction method of multipliers is presented to solve the positive semidefinite programming. Finally, the matrix enhancement and matrix pencil method is introduced to process the obtained pressure and reconstruct the source distribution. Both simulations and experiments demonstrate that under certain conditions, the grid-free compressive beamforming can provide high-resolution and low-contamination imaging, allowing accurate and fast estimation of two-dimensional DOAs and quantification of source strengths, even with non-uniform arrays and noisy measurements.

Comparing In-Class and Out-of-Class Computer-Based Tests to Traditional Paper-and-Pencil Tests in Introductory Psychology Courses

ERIC Educational Resources Information Center

Frein, Scott T.

2011-01-01

This article describes three experiments comparing paper-and-pencil tests (PPTs) to computer-based tests (CBTs) in terms of test method preferences and student performance. In Experiment 1, students took tests using three methods: PPT in class, CBT in class, and CBT at the time and place of their choosing. Results indicate that test method did not…

Wood texture classification by fuzzy neural networks

NASA Astrophysics Data System (ADS)

Gonzaga, Adilson; de Franca, Celso A.; Frere, Annie F.

1999-03-01

The majority of scientific papers focusing on wood classification for pencil manufacturing take into account defects and visual appearance. Traditional methodologies are base don texture analysis by co-occurrence matrix, by image modeling, or by tonal measures over the plate surface. In this work, we propose to classify plates of wood without biological defects like insect holes, nodes, and cracks, by analyzing their texture. By this methodology we divide the plate image in several rectangular windows or local areas and reduce the number of gray levels. From each local area, we compute the histogram of difference sand extract texture features, given them as input to a Local Neuro-Fuzzy Network. Those features are from the histogram of differences instead of the image pixels due to their better performance and illumination independence. Among several features like media, contrast, second moment, entropy, and IDN, the last three ones have showed better results for network training. Each LNN output is taken as input to a Partial Neuro-Fuzzy Network (PNFN) classifying a pencil region on the plate. At last, the outputs from the PNFN are taken as input to a Global Fuzzy Logic doing the plate classification. Each pencil classification within the plate is done taking into account each quality index.

SU-F-T-147: An Alternative Parameterization of Scatter Behavior Allows Significant Reduction of Beam Characterization for Pencil Beam Proton Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van den Heuvel, F; Fiorini, F; George, B

2016-06-15

Purpose: 1) To describe the characteristics of pencil beam proton dose deposition kernels in a homogenous medium using a novel parameterization. 2) To propose a method utilizing this novel parametrization to reduce the measurements and pre-computation required in commissioning a pencil beam proton therapy system. Methods: Using beam data from a clinical, pencil beam proton therapy center, Monte Carlo simulations were performed to characterize the dose depositions at a range of energies from 100.32 to 226.08 MeV in 3.6MeV steps. At each energy, the beam is defined at the surface of the phantom by a two-dimensional Normal distribution. Using FLUKA,more » the in-medium dose distribution is calculated in 200×200×350 mm cube with 1 mm{sup 3} tally volumes. The calculated dose distribution in each 200×200 slice perpendicular to the beam axis is then characterized using a symmetric alpha-stable distribution centered on the beam axis. This results in two parameters, α and γ, that completely describe shape of the distribution. In addition, the total dose deposited on each slice is calculated. The alpha-stable parameters are plotted as function of the depth in-medium, providing a representation of dose deposition along the pencil beam. We observed that these graphs are isometric through a scaling of both abscissa and ordinate map the curves. Results: Using interpolation of the scaling factors of two source curves representative of different beam energies, we predicted the parameters of a third curve at an intermediate energy. The errors are quantified by the maximal difference and provide a fit better than previous methods. The maximal energy difference between the source curves generating identical curves was 21.14MeV. Conclusion: We have introduced a novel method to parameterize the in-phantom properties of pencil beam proton dose depositions. For the case of the Knoxville IBA system, no more than nine pencil beams have to be fully characterized.« less

Trace for Differential Pencils on a Star-Type Graph

NASA Astrophysics Data System (ADS)

Yang, Chuan-Fu

2013-07-01

In this work, we consider the spectral problem for differential pencils on a star-type graph with a Kirchhoff-type condition in the internal vertex. The regularized trace formula of this operator is established with the contour integration method in complex analysis.

Parallel Symmetric Eigenvalue Problem Solvers

DTIC Science & Technology

2015-05-01

tutoring, and mentoring experience as an undergraduate. Last but not least, I thank my family for their love and support. v TABLE OF CONTENTS Page LIST...34 4.6.2 Choice of the Ritz shifts . . . . . . . . . . . . . . . . . . . . 38 4.7 Relationship between TraceMin and...which are determined by the Ritz values of the matrix pencil. We conclude with a discussion of the relationship between TraceMin and simultaneous

Computer Availability and Principals' Perceptions of Online Surveys

ERIC Educational Resources Information Center

Eaton, Danice K.; Brener, Nancy D.; Kann, Laura; Roberts, Alice M.; Kyle, Tonja M.; Flint, Katherine H.; Ross, Alexander L. R.

2011-01-01

Background: School-based risk behavior surveys traditionally have been administered via paper-and-pencil. This study assessed the feasibility of conducting in-class online surveys in US high schools. Methods: A paper-and-pencil questionnaire assessing computer availability and perceptions of online surveys was mailed to a nationally representative…

Comparison of Paper-Pencil and Online Performances of Students with Learning Disabilities

ERIC Educational Resources Information Center

Taherbhai, Husein; Seo, Daeryong; Bowman, Trinell

2012-01-01

Literature in the United States provides many examples of no difference in student achievement when measured against the mode of test administration i.e., paper-pencil and online versions of the test. However, most of these researches centre on "regular" students who do not require differential teaching methods or different evaluation…

Double-Polymer-Modified Pencil Lead for Stripping Voltammetry of Perchlorate in Drinking Water

ERIC Educational Resources Information Center

Izadyar, Anahita; Kim, Yushin; Ward, Michelle M.; Amemiya, Shigeru

2012-01-01

The inexpensive and disposable electrode based on a double-polymer-modified pencil lead is proposed for upper-division undergraduate instrumental laboratories to enable the highly sensitive detection of perchlorate. Students fabricate and utilize their own electrodes in the 3-4 h laboratory session to learn important concepts and methods of…

Toxic Effect of Cadmium Assay in Contaminated Soil Earthworm Cell Using Modified Sensor

PubMed Central

Kyung, Lee; Kim, Chae Hwa; Seo, Roma; Lee, Soo Youn; Kim, Lina; Chae, Su min; Choi, Sung Wook; Kim, Ji Yoon

2015-01-01

A voltammetric toxic metal of cadmium detection was studied using a fluorine doped graphite pencil electrode (FPE) in a seawater electrolyte. In this study, square wave (SW) stripping and chronoamerometry were used for determination of Cd(II) in seawater. Affordable pencils and an auxiliary electrode were used as reference. All experiments in this study could be performed at reasonable cost by using graphite pencil. The application was performed on the tissue of contaminated soil earthworm. The results show that the method can be applicable for vegetables and in vivo fluid or medicinal diagnosis. PMID:26191388

Minimum Fisher regularization of image reconstruction for infrared imaging bolometer on HL-2A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, J. M.; Liu, Y.; Li, W.

2013-09-15

An infrared imaging bolometer diagnostic has been developed recently for the HL-2A tokamak to measure the temporal and spatial distribution of plasma radiation. The three-dimensional tomography, reduced to a two-dimensional problem by the assumption of plasma radiation toroidal symmetry, has been performed. A three-dimensional geometry matrix is calculated with the one-dimensional pencil beam approximation. The solid angles viewed by the detector elements are taken into account in defining the chord brightness. And the local plasma emission is obtained by inverting the measured brightness with the minimum Fisher regularization method. A typical HL-2A plasma radiation model was chosen to optimize amore » regularization parameter on the criterion of generalized cross validation. Finally, this method was applied to HL-2A experiments, demonstrating the plasma radiated power density distribution in limiter and divertor discharges.« less

An efficient quantum algorithm for spectral estimation

NASA Astrophysics Data System (ADS)

Steffens, Adrian; Rebentrost, Patrick; Marvian, Iman; Eisert, Jens; Lloyd, Seth

2017-03-01

We develop an efficient quantum implementation of an important signal processing algorithm for line spectral estimation: the matrix pencil method, which determines the frequencies and damping factors of signals consisting of finite sums of exponentially damped sinusoids. Our algorithm provides a quantum speedup in a natural regime where the sampling rate is much higher than the number of sinusoid components. Along the way, we develop techniques that are expected to be useful for other quantum algorithms as well—consecutive phase estimations to efficiently make products of asymmetric low rank matrices classically accessible and an alternative method to efficiently exponentiate non-Hermitian matrices. Our algorithm features an efficient quantum-classical division of labor: the time-critical steps are implemented in quantum superposition, while an interjacent step, requiring much fewer parameters, can operate classically. We show that frequencies and damping factors can be obtained in time logarithmic in the number of sampling points, exponentially faster than known classical algorithms.

Fabrication and characterization of a nanometer-sized optical fiber electrode based on selective chemical etching for scanning electrochemical/optical microscopy.

PubMed

Maruyama, Kenichi; Ohkawa, Hiroyuki; Ogawa, Sho; Ueda, Akio; Niwa, Osamu; Suzuki, Koji

2006-03-15

We have already reported a method for fabricating ultramicroelectrodes (Suzuki, K. JP Patent, 2004-45394, 2004). This method is based on the selective chemical etching of optical fibers. In this work, we undertake a detailed investigation involving a combination of etched optical fibers with various types of tapered tip (protruding-shape, double- (or pencil-) shape and triple-tapered electrode) and insulation with electrophoretic paint. Our goal is to establish a method for fabricating nanometer-sized optical fiber electrodes with high reproducibility. As a result, we realized pencil-shaped and triple-tapered electrodes that had radii in the nanometer range with high reproducibility. These nanometer-sized electrodes showed well-defined sigmoidal curves and stable diffusion-limited responses with cyclic voltammetry. The pencil-shaped optical fiber, which has a conical tip with a cone angle of 20 degrees , was effective for controlling the electrode radius. The pencil-shaped electrodes had higher reproducibility and smaller electrode radii (r(app) < 1.0 nm) than those of other etched optical fiber electrodes. By using a pencil-shaped electrode with a 105-nm radius as a probe, we obtained simultaneous electrochemical and optical images of an implantable interdigitated array electrode. We achieved nanometer-scale resolution with a combination of scanning electrochemical microscopy SECM and optical microscopy. The resolution of the electrochemical and optical images indicated sizes of 300 and 930 nm, respectively. The neurites of living PC12 cells were also successfully imaged on a 1.6-microm scale by using the negative feedback mode of an SECM.

Characterisation of mega-voltage electron pencil beam dose distributions: viability of a measurement-based approach.

PubMed

Barnes, M P; Ebert, M A

2008-03-01

The concept of electron pencil-beam dose distributions is central to pencil-beam algorithms used in electron beam radiotherapy treatment planning. The Hogstrom algorithm, which is a common algorithm for electron treatment planning, models large electron field dose distributions by the superposition of a series of pencil beam dose distributions. This means that the accurate characterisation of an electron pencil beam is essential for the accuracy of the dose algorithm. The aim of this study was to evaluate a measurement based approach for obtaining electron pencil-beam dose distributions. The primary incentive for the study was the accurate calculation of dose distributions for narrow fields as traditional electron algorithms are generally inaccurate for such geometries. Kodak X-Omat radiographic film was used in a solid water phantom to measure the dose distribution of circular 12 MeV beams from a Varian 21EX linear accelerator. Measurements were made for beams of diameter, 1.5, 2, 4, 8, 16 and 32 mm. A blocked-field technique was used to subtract photon contamination in the beam. The "error function" derived from Fermi-Eyges Multiple Coulomb Scattering (MCS) theory for corresponding square fields was used to fit resulting dose distributions so that extrapolation down to a pencil beam distribution could be made. The Monte Carlo codes, BEAM and EGSnrc were used to simulate the experimental arrangement. The 8 mm beam dose distribution was also measured with TLD-100 microcubes. Agreement between film, TLD and Monte Carlo simulation results were found to be consistent with the spatial resolution used. The study has shown that it is possible to extrapolate narrow electron beam dose distributions down to a pencil beam dose distribution using the error function. However, due to experimental uncertainties and measurement difficulties, Monte Carlo is recommended as the method of choice for characterising electron pencil-beam dose distributions.

Polarimetric imaging of turbid inhomogeneous slab media based on backscattering using a pencil beam for illumination: Monte Carlo simulation

NASA Astrophysics Data System (ADS)

Otsuki, Soichi

2018-04-01

Polarimetric imaging of absorbing, strongly scattering, or birefringent inclusions is investigated in a negligibly absorbing, moderately scattering, and isotropic slab medium. It was proved that the reduced effective scattering Mueller matrix is exactly calculated from experimental or simulated raw matrices even if the medium is anisotropic and/or heterogeneous, or the outgoing light beam exits obliquely to the normal of the slab surface. The calculation also gives a reasonable approximation of the reduced matrix using a light beam with a finite diameter for illumination. The reduced matrix was calculated using a Monte Carlo simulation and was factorized in two dimensions by the Lu-Chipman polar decomposition. The intensity of backscattered light shows clear and modestly clear differences for absorbing and strongly scattering inclusions, respectively, whereas it shows no difference for birefringent inclusions. Conversely, some polarization parameters, for example, the selective depolarization coefficients exhibit only a slight difference for the absorbing inclusions, whereas they showed clear difference for the strongly scattering or birefringent inclusions. Moreover, these quantities become larger with increasing the difference in the optical properties of the inclusions relative to the surrounding medium. However, it is difficult to recognize inclusions that buried at the depth deeper than 3 mm under the surface. Thus, the present technique can detect the approximate shape and size of these inclusions, and considering the depth where inclusions lie, estimate their optical properties. This study reveals the possibility of the polarization-sensitive imaging of turbid inhomogeneous media using a pencil beam for illumination.

Internet Administration of the Paper-and-Pencil Gifted Rating Scale: Assessing Psychometric Equivalence

ERIC Educational Resources Information Center

Yarnell, Jordy B.; Pfeiffer, Steven I.

2015-01-01

The present study examined the psychometric equivalence of administering a computer-based version of the Gifted Rating Scale (GRS) compared with the traditional paper-and-pencil GRS-School Form (GRS-S). The GRS-S is a teacher-completed rating scale used in gifted assessment. The GRS-Electronic Form provides an alternative method of administering…

Pencil Pressure and Anxiety in Drawings: A Techno-Projective Approach

ERIC Educational Resources Information Center

LaRoque, Sean Davis; Obrzut, John E.

2006-01-01

This study used a techno-projective assessment method to analyze the relationship between pencil pressure applied during drawing tasks and state anxiety (S-anxiety) and trait anxiety (T-anxiety) levels. A highly accurate and precise pressure-sensitive palette was used by participants (N = 50) between the ages of 6 and 11 to reliably and…

Investigation of colloidal graphite as a matrix for matrix-assisted laser desorption/ionisation mass spectrometry of low molecular weight analytes.

PubMed

Warren, Alexander D; Conway, Ulric; Arthur, Christopher J; Gates, Paul J

2016-07-01

The analysis of low molecular weight compounds by matrix-assisted laser desorption/ionisation mass spectrometry is problematic due to the interference and suppression of analyte ionisation by the matrices typically employed - which are themselves low molecular weight compounds. The application of colloidal graphite is demonstrated here as an easy to use matrix that can promote the ionisation of a wide range of analytes including low molecular weight organic compounds, complex natural products and inorganic complexes. Analyte ionisation with colloidal graphite is compared with traditional organic matrices along with various other sources of graphite (e.g. graphite rods and charcoal pencils). Factors such as ease of application, spectra reproducibility, spot longevity, spot-to-spot reproducibility and spot homogeneity (through single spot imaging) are explored. For some analytes, considerable matrix suppression effects are observed resulting in spectra completely devoid of matrix ions. We also report the observation of radical molecular ions [M(-●) ] in the negative ion mode, particularly with some aromatic analytes. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Calculation of normal modes of the closed waveguides in general vector case

NASA Astrophysics Data System (ADS)

Malykh, M. D.; Sevastianov, L. A.; Tiutiunnik, A. A.

2018-04-01

The article is devoted to the calculation of normal modes of the closed waveguides with an arbitrary filling ɛ, μ in the system of computer algebra Sage. Maxwell equations in the cylinder are reduced to the system of two bounded Helmholtz equations, the notion of weak solution of this system is given and then this system is investigated as a system of ordinary differential equations. The normal modes of this system are an eigenvectors of a matrix pencil. We suggest to calculate the matrix elements approximately and to truncate the matrix by usual way but further to solve the truncated eigenvalue problem exactly in the field of algebraic numbers. This approach allows to keep the symmetry of the initial problem and in particular the multiplicity of the eigenvalues. In the work would be presented some results of calculations.

Exploring the Effects of Employing Google Docs in Collaborative Concept Mapping on Achievement, Concept Representation, and Attitudes

ERIC Educational Resources Information Center

Lin, Yu-Tzu; Chang, Chia-Hu; Hou, Huei-Tse; Wu, Ke-Chou

2016-01-01

This study investigated the effectiveness of using Google Docs in collaborative concept mapping (CCM) by comparing it with a paper-and-pencil approach. A quasi-experimental study was conducted in a physics course. The control group drew concept maps using the paper-and-pencil method and face-to-face discussion, whereas the experimental group…

Students’ thinking preferences in solving mathematics problems based on learning styles: a comparison of paper-pencil and geogebra

NASA Astrophysics Data System (ADS)

Farihah, Umi

2018-04-01

The purpose of this study was to analyze students’ thinking preferences in solving mathematics problems using paper pencil comparing to geogebra based on their learning styles. This research employed a qualitative descriptive study. The subjects of this research was six of eighth grade students of Madrasah Tsanawiyah Negeri 2 Trenggalek, East Java Indonesia academic year 2015-2016 with their difference learning styles; two visual students, two auditory students, and two kinesthetic students.. During the interview, the students presented the Paper and Pencil-based Task (PBTs) and the Geogebra-based Task (GBTs). By investigating students’ solution methods and the representation in solving the problems, the researcher compared their visual and non-visual thinking preferences in solving mathematics problems while they were using Geogebra and without Geogebra. Based on the result of research analysis, it was shown that the comparison between students’ PBTs and GBTs solution either visual, auditory, or kinesthetic represented how Geogebra can influence their solution method. By using Geogebra, they prefer using visual method while presenting GBTs to using non-visual method.

Design of a QA method to characterize submillimeter-sized PBS beam properties using a 2D ionization chamber array

NASA Astrophysics Data System (ADS)

Lin, Yuting; Bentefour, Hassan; Flanz, Jacob; Kooy, Hanne; Clasie, Benjamin

2018-05-01

Pencil beam scanning (PBS) periodic quality assurance (QA) programs ensure the beam delivered to patients is within technical specifications. Two critical specifications for PBS delivery are the beam width and position. The aim of this study is to investigate whether a 2D ionization chamber array, such as the MatriXX detector (IBA Dosimetry, Schwarzenbruck, Germany), can be used to characterize submillimeter-sized PBS beam properties. The motivation is to use standard equipment, which may have pixel spacing coarser than the pencil beam size, and simplify QA workflow. The MatriXX pixels are cylindrical in shape with 4.5 mm diameter and are spaced 7.62 mm from center to center. Two major effects limit the ability of using the MatriXX to measure the spot position and width accurately. The first effect is that too few pixels sample the Gaussian shaped pencil beam profile and the second effect is volume averaging of the Gaussian profile over the pixel sensitive volumes. We designed a method that overcomes both limitations and hence enables the use of the MatriXX to characterize sub-millimeter-sized PBS beam properties. This method uses a cross-like irradiation pattern that is designed to increase the number of sampling data points and a modified Gaussian fitting technique to correct for volume averaging effects. Detector signals were calculated in this study and random noise and setup errors were added to simulate measured data. With the techniques developed in this work, the MatriXX detector can be used to characterize the position and width of sub-millimeter, σ  =  0.7 mm, sized pencil beams with uncertainty better than 3% relative to σ. With the irradiation only covering 60% of the MatriXX, the position and width of σ  =  0.9 mm sized pencil beams can be determined with uncertainty better than 3% relative to σ. If one were to not use a cross-like irradiation pattern, then the position and width of σ  =  3.6 mm sized pencil beams can be determined with uncertainty better than 3% relative to σ. If one were to not use a cross-like pattern nor volume averaging corrections, then the position and width of σ  =  5.0 mm sized pencil beams can be determined with uncertainty better than 3% relative to σ. This work helps to simplify periodic QA in proton therapy because more routinely used ionization chamber arrays can be used to characterize narrow pencil beam properties.

Design of a QA method to characterize submillimeter-sized PBS beam properties using a 2D ionization chamber array.

PubMed

Lin, Yuting; Bentefour, Hassan; Flanz, Jacob; Kooy, Hanne; Clasie, Benjamin

2018-05-15

Pencil beam scanning (PBS) periodic quality assurance (QA) programs ensure the beam delivered to patients is within technical specifications. Two critical specifications for PBS delivery are the beam width and position. The aim of this study is to investigate whether a 2D ionization chamber array, such as the MatriXX detector (IBA Dosimetry, Schwarzenbruck, Germany), can be used to characterize submillimeter-sized PBS beam properties. The motivation is to use standard equipment, which may have pixel spacing coarser than the pencil beam size, and simplify QA workflow. The MatriXX pixels are cylindrical in shape with 4.5 mm diameter and are spaced 7.62 mm from center to center. Two major effects limit the ability of using the MatriXX to measure the spot position and width accurately. The first effect is that too few pixels sample the Gaussian shaped pencil beam profile and the second effect is volume averaging of the Gaussian profile over the pixel sensitive volumes. We designed a method that overcomes both limitations and hence enables the use of the MatriXX to characterize sub-millimeter-sized PBS beam properties. This method uses a cross-like irradiation pattern that is designed to increase the number of sampling data points and a modified Gaussian fitting technique to correct for volume averaging effects. Detector signals were calculated in this study and random noise and setup errors were added to simulate measured data. With the techniques developed in this work, the MatriXX detector can be used to characterize the position and width of sub-millimeter, σ  =  0.7 mm, sized pencil beams with uncertainty better than 3% relative to σ. With the irradiation only covering 60% of the MatriXX, the position and width of σ  =  0.9 mm sized pencil beams can be determined with uncertainty better than 3% relative to σ. If one were to not use a cross-like irradiation pattern, then the position and width of σ  =  3.6 mm sized pencil beams can be determined with uncertainty better than 3% relative to σ. If one were to not use a cross-like pattern nor volume averaging corrections, then the position and width of σ  =  5.0 mm sized pencil beams can be determined with uncertainty better than 3% relative to σ. This work helps to simplify periodic QA in proton therapy because more routinely used ionization chamber arrays can be used to characterize narrow pencil beam properties.

Comparison of cutting and pencil-point spinal needle in spinal anesthesia regarding postdural puncture headache

PubMed Central

Xu, Hong; Liu, Yang; Song, WenYe; Kan, ShunLi; Liu, FeiFei; Zhang, Di; Ning, GuangZhi; Feng, ShiQing

2017-01-01

Abstract Background: Postdural puncture headache (PDPH), mainly resulting from the loss of cerebral spinal fluid (CSF), is a well-known iatrogenic complication of spinal anesthesia and diagnostic lumbar puncture. Spinal needles have been modified to minimize complications. Modifiable risk factors of PDPH mainly included needle size and needle shape. However, whether the incidence of PDPH is significantly different between cutting-point and pencil-point needles was controversial. Then we did a meta-analysis to assess the incidence of PDPH of cutting spinal needle and pencil-point spinal needle. Methods: We included all randomly designed trials, assessing the clinical outcomes in patients given elective spinal anesthesia or diagnostic lumbar puncture with either cutting or pencil-point spinal needle as eligible studies. All selected studies and the risk of bias of them were assessed by 2 investigators. Clinical outcomes including success rates, frequency of PDPH, reported severe PDPH, and the use of epidural blood patch (EBP) were recorded as primary results. Results were evaluated using risk ratio (RR) with 95% confidence interval (CI) for dichotomous variables. Rev Man software (version 5.3) was used to analyze all appropriate data. Results: Twenty-five randomized controlled trials (RCTs) were included in our study. The analysis result revealed that pencil-point spinal needle would result in lower rate of PDPH (RR 2.50; 95% CI [1.96, 3.19]; P < 0.00001) and severe PDPH (RR 3.27; 95% CI [2.15, 4.96]; P < 0.00001). Furthermore, EBP was less used in pencil-point spine needle group (RR 3.69; 95% CI [1.96, 6.95]; P < 0.0001). Conclusions: Current evidences suggest that pencil-point spinal needle was significantly superior compared with cutting spinal needle regarding the frequency of PDPH, PDPH severity, and the use of EBP. In view of this, we recommend the use of pencil-point spinal needle in spinal anesthesia and lumbar puncture. PMID:28383416

Comparison of Paper-and-Pencil versus Web Administration of the Youth Risk Behavior Survey (YRBS): Risk Behavior Prevalence Estimates

ERIC Educational Resources Information Center

Eaton, Danice K.; Brener, Nancy D.; Kann, Laura; Denniston, Maxine M.; McManus, Tim; Kyle, Tonja M.; Roberts, Alice M.; Flint, Katherine H.; Ross, James G.

2010-01-01

The authors examined whether paper-and-pencil and Web surveys administered in the school setting yield equivalent risk behavior prevalence estimates. Data were from a methods study conducted by the Centers for Disease Control and Prevention (CDC) in spring 2008. Intact classes of 9th- or 10th-grade students were assigned randomly to complete a…

A non-stochastic iterative computational method to model light propagation in turbid media

NASA Astrophysics Data System (ADS)

McIntyre, Thomas J.; Zemp, Roger J.

2015-03-01

Monte Carlo models are widely used to model light transport in turbid media, however their results implicitly contain stochastic variations. These fluctuations are not ideal, especially for inverse problems where Jacobian matrix errors can lead to large uncertainties upon matrix inversion. Yet Monte Carlo approaches are more computationally favorable than solving the full Radiative Transport Equation. Here, a non-stochastic computational method of estimating fluence distributions in turbid media is proposed, which is called the Non-Stochastic Propagation by Iterative Radiance Evaluation method (NSPIRE). Rather than using stochastic means to determine a random walk for each photon packet, the propagation of light from any element to all other elements in a grid is modelled simultaneously. For locally homogeneous anisotropic turbid media, the matrices used to represent scattering and projection are shown to be block Toeplitz, which leads to computational simplifications via convolution operators. To evaluate the accuracy of the algorithm, 2D simulations were done and compared against Monte Carlo models for the cases of an isotropic point source and a pencil beam incident on a semi-infinite turbid medium. The model was shown to have a mean percent error less than 2%. The algorithm represents a new paradigm in radiative transport modelling and may offer a non-stochastic alternative to modeling light transport in anisotropic scattering media for applications where the diffusion approximation is insufficient.

Does Assessment Type Matter? A Measurement Invariance Analysis of Online and Paper and Pencil Assessment of the Community Assessment of Psychic Experiences (CAPE)

PubMed Central

Vleeschouwer, Marloes; Schubart, Chris D.; Henquet, Cecile; Myin-Germeys, Inez; van Gastel, Willemijn A.; Hillegers, Manon H. J.; van Os, Jim J.; Boks, Marco P. M.; Derks, Eske M.

2014-01-01

Background The psychometric properties of an online test are not necessarily identical to its paper and pencil original. The aim of this study is to test whether the factor structure of the Community Assessment of Psychic Experiences (CAPE) is measurement invariant with respect to online vs. paper and pencil assessment. Method The factor structure of CAPE items assessed by paper and pencil (N = 796) was compared with the factor structure of CAPE items assessed by the Internet (N = 21,590) using formal tests for Measurement Invariance (MI). The effect size was calculated by estimating the Signed Item Difference in the Sample (SIDS) index and the Signed Test Difference in the Sample (STDS) for a hypothetical subject who scores 2 standard deviations above average on the latent dimensions. Results The more restricted Metric Invariance model showed a significantly worse fit compared to the less restricted Configural Invariance model (χ2(23) = 152.75, p<0.001). However, the SIDS indices appear to be small, with an average of −0.11. A STDS of −4.80 indicates that Internet sample members who score 2 standard deviations above average would be expected to score 4.80 points lower on the CAPE total scale (ranging from 42 to 114 points) than would members of the Paper sample with the same latent trait score. Conclusions Our findings did not support measurement invariance with respect to assessment method. Because of the small effect sizes, the measurement differences between the online assessed CAPE and its paper and pencil original can be neglected without major consequences for research purposes. However, a person with a high vulnerability for psychotic symptoms would score 4.80 points lower on the total scale if the CAPE is assessed online compared to paper and pencil assessment. Therefore, for clinical purposes, one should be cautious with online assessment of the CAPE. PMID:24465389

Bisimulation equivalence of differential-algebraic systems

NASA Astrophysics Data System (ADS)

Megawati, Noorma Yulia; Schaft, Arjan van der

2018-01-01

In this paper, the notion of bisimulation relation for linear input-state-output systems is extended to general linear differential-algebraic (DAE) systems. Geometric control theory is used to derive a linear-algebraic characterisation of bisimulation relations, and an algorithm for computing the maximal bisimulation relation between two linear DAE systems. The general definition is specialised to the case where the matrix pencil sE - A is regular. Furthermore, by developing a one-sided version of bisimulation, characterisations of simulation and abstraction are obtained.

A new adaptive algorithm for automated feature extraction in exponentially damped signals for health monitoring of smart structures

NASA Astrophysics Data System (ADS)

Qarib, Hossein; Adeli, Hojjat

2015-12-01

In this paper authors introduce a new adaptive signal processing technique for feature extraction and parameter estimation in noisy exponentially damped signals. The iterative 3-stage method is based on the adroit integration of the strengths of parametric and nonparametric methods such as multiple signal categorization, matrix pencil, and empirical mode decomposition algorithms. The first stage is a new adaptive filtration or noise removal scheme. The second stage is a hybrid parametric-nonparametric signal parameter estimation technique based on an output-only system identification technique. The third stage is optimization of estimated parameters using a combination of the primal-dual path-following interior point algorithm and genetic algorithm. The methodology is evaluated using a synthetic signal and a signal obtained experimentally from transverse vibrations of a steel cantilever beam. The method is successful in estimating the frequencies accurately. Further, it estimates the damping exponents. The proposed adaptive filtration method does not include any frequency domain manipulation. Consequently, the time domain signal is not affected as a result of frequency domain and inverse transformations.

Characterization of scatter in digital mammography from physical measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leon, Stephanie M., E-mail: Stephanie.Leon@uth.tmc.edu; Wagner, Louis K.; Brateman, Libby F.

2014-06-15

Purpose: That scattered radiation negatively impacts the quality of medical radiographic imaging is well known. In mammography, even slight amounts of scatter reduce the high contrast required for subtle soft-tissue imaging. In current clinical mammography, image contrast is partially improved by use of an antiscatter grid. This form of scatter rejection comes with a sizeable dose penalty related to the concomitant elimination of valuable primary radiation. Digital mammography allows the use of image processing as a method of scatter correction that might avoid effects that negatively impact primary radiation, while potentially providing more contrast improvement than is currently possible withmore » a grid. For this approach to be feasible, a detailed characterization of the scatter is needed. Previous research has modeled scatter as a constant background that serves as a DC bias across the imaging surface. The goal of this study was to provide a more substantive data set for characterizing the spatially-variant features of scatter radiation at the image detector of modern mammography units. Methods: This data set was acquired from a model of the radiation beam as a matrix of very narrow rays or pencil beams. As each pencil beam penetrates tissue, the pencil widens in a predictable manner due to the production of scatter. The resultant spreading of the pencil beam at the detector surface can be characterized by two parameters: mean radial extent (MRE) and scatter fraction (SF). The SF and MRE were calculated from measurements obtained using the beam stop method. Two digital mammography units were utilized, and the SF and MRE were found as functions of target, filter, tube potential, phantom thickness, and presence or absence of a grid. These values were then used to generate general equations allowing the SF and MRE to be calculated for any combination of the above parameters. Results: With a grid, the SF ranged from a minimum of about 0.05 to a maximum of about 0.16, and the MRE ranged from about 3 to 13 mm. Without a grid, the SF ranged from a minimum of 0.25 to a maximum of 0.52, and the MRE ranged from about 20 to 45 mm. The SF with a grid demonstrated a mild dependence on target/filter combination and kV, whereas the SF without a grid was independent of these factors. The MRE demonstrated a complex relationship as a function of kV, with notable difference among target/filter combinations. The primary source of change in both the SF and MRE was phantom thickness. Conclusions: Because breast tissue varies spatially in physical density and elemental content, the effective thickness of breast tissue varies spatially across the imaging field, resulting in a spatially-variant scatter distribution in the imaging field. The data generated in this study can be used to characterize the scatter contribution on a point-by-point basis, for a variety of different techniques.« less

Description of Primary Education 1st Grade Students' Forms of Holding a Pencil as well as Their Grip and Compression Strengths

ERIC Educational Resources Information Center

Temur, Turan

2011-01-01

This study aimed to examine how first grade students in primary education held and gripped a pencil and their compressive strength using a descriptive research method. The participants of the research comprises first grade students attending a private school in the city center of Ankara (n=79). All of the four different sections in this private…

Accurate Simulation of Acoustic Emission Sources in Composite Plates

NASA Technical Reports Server (NTRS)

Prosser, W. H.; Gorman, M. R.

1994-01-01

Acoustic emission (AE) signals propagate as the extensional and flexural plate modes in thin composite plates and plate-like geometries such as shells, pipes, and tubes. The relative amplitude of the two modes depends on the directionality of the source motion. For source motions with large out-of-plane components such as delaminations or particle impact, the flexural or bending plate mode dominates the AE signal with only a small extensional mode detected. A signal from such a source is well simulated with the standard pencil lead break (Hsu-Neilsen source) on the surface of the plate. For other sources such as matrix cracking or fiber breakage in which the source motion is primarily in-plane, the resulting AE signal has a large extensional mode component with little or no flexural mode observed. Signals from these type sources can also be simulated with pencil lead breaks. However, the lead must be fractured on the edge of the plate to generate an in-plane source motion rather than on the surface of the plate. In many applications such as testing of pressure vessels and piping or aircraft structures, a free edge is either not available or not in a desired location for simulation of in-plane type sources. In this research, a method was developed which allows the simulation of AE signals with a predominant extensional mode component in composite plates requiring access to only the surface of the plate.

Cyclic voltammetry deposition of copper nanostructure on MWCNTs modified pencil graphite electrode: An ultra-sensitive hydrazine sensor.

PubMed

Heydari, Hamid; Gholivand, Mohammad B; Abdolmaleki, Abbas

2016-09-01

In this study, Copper (Cu) nanostructures (CuNS) were electrochemically deposited on a film of multiwall carbon nanotubes (MWCNTs) modified pencil graphite electrode (MWCNTs/PGE) by cyclic voltammetry method to fabricate a CuNS-MWCNTs composite sensor (CuNS-MWCNT/PGE) for hydrazine detection. Scanning electron microscopy (SEM) and Energy-dispersive X-ray spectroscopy (EDX) were used for the characterization of CuNS on the MWCNTs matrix. The composite of CuNS-MWCNTs was characterized with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The preliminary studies showed that the proposed sensor have a synergistic electrocatalytic activity for the oxidation of hydrazine in phosphate buffer. The catalytic currents of square wave voltammetry had a linear correlation with the hydrazine concentration in the range of 0.1 to 800μM with a low detection limit of 70nM. Moreover, the amperometric oxidation current exhibited a linear correlation with hydrazine concentration in the concentration range of 50-800μM with the detection limit of 4.3μM. The proposed electrode was used for the determination of hydrazine in real samples and the results were promising. Empirical results also indicated that the sensor had good reproducibility, long-term stability, and the response of the sensor to hydrazine was free from interferences. Moreover, the proposed sensor benefits from simple preparation, low cost, outstanding sensitivity, selectivity, and reproducibility for hydrazine determination. Copyright © 2016. Published by Elsevier B.V.

Anodic Stripping Voltammetry with Pencil Graphite Electrode for Determination of Chromium (III)

NASA Astrophysics Data System (ADS)

Wyantuti, S.; Hafidza, R. A.; Ishmayana, S.; Hartati, Y. W.

2017-02-01

Chromium is required as micronutrient that has roles in insulin metabolism and blood glucose level regulation. Chromium (III) deficiency can cause hyperglycemia and glycosuria. However, a high amount of chromium in body can cause allergic reaction, organ damage, and even death because of its toxicity. Chromium is commonly used in steel industries. Simultaneously with the development of industry, the waste disposal that can endanger environment also increased. Therefore, a sensitive and specific analysis method for chromium detection is required. Stripping voltammetry is one of the voltammetric methods that is commonly used for heavy metal analysis due to the very low limit of detection (sub ppb). The present study was conducted to develop an analysis method for chromium (III) determination using pencil graphite electrode. Quantitative determination was performed for chromium (III) which measured at -0.8 to +1.0 V with deposition time for 60 s and 50 mV/s scan rate. Stripping voltammetric analysis of chromium (III) using pencil graphite electrode gave linear range at 12.5 to 75 ppm with limit of detection of 0.31 ppm.

Accounting for range uncertainties in the optimization of intensity modulated proton therapy.

PubMed

Unkelbach, Jan; Chan, Timothy C Y; Bortfeld, Thomas

2007-05-21

Treatment plans optimized for intensity modulated proton therapy (IMPT) may be sensitive to range variations. The dose distribution may deteriorate substantially when the actual range of a pencil beam does not match the assumed range. We present two treatment planning concepts for IMPT which incorporate range uncertainties into the optimization. The first method is a probabilistic approach. The range of a pencil beam is assumed to be a random variable, which makes the delivered dose and the value of the objective function a random variable too. We then propose to optimize the expectation value of the objective function. The second approach is a robust formulation that applies methods developed in the field of robust linear programming. This approach optimizes the worst case dose distribution that may occur, assuming that the ranges of the pencil beams may vary within some interval. Both methods yield treatment plans that are considerably less sensitive to range variations compared to conventional treatment plans optimized without accounting for range uncertainties. In addition, both approaches--although conceptually different--yield very similar results on a qualitative level.

SU-E-T-375: Passive Scattering to Pencil-Beam-Scanning Comparison for Medulloblastoma Proton Therapy: LET Distributions and Radiobiological Implications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giantsoudi, D; MacDonald, S; Paganetti, H

2014-06-01

Purpose: To compare the linear energy transfer (LET) distributions between passive scattering and pencil beam scanning proton radiation therapy techniques for medulloblastoma patients and study the potential radiobiological implications. Methods: A group of medulloblastoma patients, previously treated with passive scattering (PS) proton craniospinal irradiation followed by prosterior fossa or involved field boost, were selected from the patient database of our institution. Using the beam geometry and planning computed tomography (CT) image sets of the original treatment plans, pencil beam scanning (PBS) treatment plans were generated for the cranial treatment for each patient, with average beam spot size of 8mm (sigmamore » in air at isocenter). 3-dimensional dose and LET distributions were calculated by Monte Carlo methods (TOPAS) both for the original passive scattering and new pencil beam scanning treatment plans. LET volume histograms were calculated for the target and OARs and compared for the two delivery methods. Variable RBE weighted dose distributions and volume histograms were also calculated using a variable dose and LET-based model. Results: Better dose conformity was achieved with PBS planning compared to PS, leading to increased dose coverage for the boost target area and decreased average dose to the structures adjacent to it and critical structures outside the whole brain treatment field. LET values for the target were lower for PBS plans. Elevated LET values for OARs close to the boosted target areas were noticed, due to end of range of proton beams falling inside these structures, resulting in higher RBE weighted dose for these structures compared to the clinical RBE value of 1.1. Conclusion: Transitioning from passive scattering to pencil beam scanning proton radiation treatment can be dosimetrically beneficial for medulloblastoma patients. LET–guided treatment planning could contribute to better decision making for these cases, especially for critical structures at close proximity to the boosted target area.« less

Sensitive Voltammetric Determination of Natural Flavonoid Quercetin on a Disposable Graphite Lead

PubMed Central

Vu, Dai Long; Žabčíková, Simona; Ertek, Bensu; Dilgin, Yusuf

2015-01-01

Summary In this paper, a pencil graphite electrode was pretreated using chronoamperometry technique in phosphate buffer solution (pH=7.0) for sensitive determination of quercetin. Oxidation of quercetin was investigated using pretreated pencil graphite electrode and anodic stripping differential pulse voltammetry. Under optimal conditions, the anodic current of quercetin exhibited linear response to its concentration in the range from 0.001 to 1.5 µmol/L with the limit of detection of 0.3·10–3 µmol/L. The proposed method was successfully applied for the determination of quercetin in cranberry and blackcurrant juices with recovery rate from 93.2 to 94.7%. Solid-phase extraction was found to be necessary prior to voltammetric determination of quercetin in fruit juice samples using pretreated pencil graphite electrode. PMID:27904372

Optimization of pencil beam f-theta lens for high-accuracy metrology

NASA Astrophysics Data System (ADS)

Peng, Chuanqian; He, Yumei; Wang, Jie

2018-01-01

Pencil beam deflectometric profilers are common instruments for high-accuracy surface slope metrology of x-ray mirrors in synchrotron facilities. An f-theta optical system is a key optical component of the deflectometric profilers and is used to perform the linear angle-to-position conversion. Traditional optimization procedures of the f-theta systems are not directly related to the angle-to-position conversion relation and are performed with stops of large size and a fixed working distance, which means they may not be suitable for the design of f-theta systems working with a small-sized pencil beam within a working distance range for ultra-high-accuracy metrology. If an f-theta system is not well-designed, aberrations of the f-theta system will introduce many systematic errors into the measurement. A least-squares' fitting procedure was used to optimize the configuration parameters of an f-theta system. Simulations using ZEMAX software showed that the optimized f-theta system significantly suppressed the angle-to-position conversion errors caused by aberrations. Any pencil-beam f-theta optical system can be optimized with the help of this optimization method.

Do pencil-point spinal needles decrease the incidence of postdural puncture headache in reality? A comparative study between pencil-point 25G Whitacre and cutting-beveled 25G Quincke spinal needles in 320 obstetric patients

PubMed Central

Pal, Anirban; Acharya, Amita; Pal, Nidhi Dawar; Dawn, Satrajit; Biswas, Jhuma

2011-01-01

Background: Postdural puncture headache (PDPH) is a distressing complication of the subarachnoid block. The previous studies conducted, including the recent ones, do not conclusively prove that pencil-point spinal needles decrease the incidence of PDPH. In this study, we have tried to find out whether a pencil-point Whitacre needle is a better alternative than the classic cutting beveled, commonly used, Quincke spinal needle, in patients at risk of PDPH. Materials and Methods: Three hundred and twenty obstetric patients, 20-36 years of age, ASA I and II, posted for Cesarean section under subarachnoid block, were randomly assigned into two groups W and Q, where 25G Whitacre and 25G Quincke spinal needles were used, respectively. The primary objective of the study was to find out the difference in incidence of PDPH, if any, between the two groups, by using the t test and Chi square test. Results: The incidence of PDPH was 5% in group W and 28.12% in group Q, and the difference in incidence was statistically significant (P<0.001). Conclusion: The pencil-point 25G Whitacre spinal needle causes less incidence of PDPH compared to the classic 25G Quincke needle, and is recommended for use in patients at risk of PDPH. PMID:25885381

Pencil grips, legibility, and speed of fourth-graders' writing in cursive.

PubMed

Koziatek, Susan M; Powell, Nancy J

2003-01-01

The purpose of this research was to study how the speed and legibility of fourth-graders handwriting was affected by type of pencil grip on the Evaluation Tool of Children's Handwriting-Cursive. Ninety-five typically developing students and 6 students receiving special education services completed the Evaluation Tool of Children's Handwriting-Cursive (ETCH-C). Photographs were taken of their pencil grips while they wrote the alphabet. One-way ANOVAs were calculated to compare legibility rates and writing speeds by type of pencil grip. Ninety-nine of the students used one of four pencil grips including the dynamic tripod (38 students), the dynamic quadrupod (18), the lateral tripod (22), and the lateral quadrupod (21). One student used the four-finger pencil grip and one used the interdigital pencil grip. Mean cursive writing speeds were similar for all pencil grips except for the interdigital grasp. Speeds obtained were slower than recently published fourth-grade speeds ranging from a mean of 29.45 to 34.75 letters per minute. CONCLUSION. This study found the lateral quadrupod and four-finger pencil grips to be as functional as the dynamic tripod, lateral tripod, and dynamic quadrupod pencil grips. This study provides average handwriting speeds for fourth-grade students on the ETCH-C.

Beam angle selection incorporation of anatomical heterogeneities for pencil beam scanning charged-particle therapy

NASA Astrophysics Data System (ADS)

Toramatsu, Chie; Inaniwa, Taku

2016-12-01

In charged particle therapy with pencil beam scanning (PBS), localization of the dose in the Bragg peak makes dose distributions sensitive to lateral tissue heterogeneities. The sensitivity of a PBS plan to lateral tissue heterogeneities can be reduced by selecting appropriate beam angles. The purpose of this study is to develop a fast and accurate method of beam angle selection for PBS. The lateral tissue heterogeneity surrounding the path of the pencil beams at a given angle was quantified with the heterogeneity number representing the variation of the Bragg peak depth across the cross section of the beams using the stopping power ratio of body tissues with respect to water. To shorten the computation time, one-dimensional dose optimization was conducted along the central axis of the pencil beams as they were directed by the scanning magnets. The heterogeneity numbers were derived for all possible beam angles for treatment. The angles leading to the minimum mean heterogeneity number were selected as the optimal beam angle. Three clinical cases of head and neck cancer were used to evaluate the developed method. Dose distributions and their robustness to setup and range errors were evaluated for all tested angles, and their relation to the heterogeneity numbers was investigated. The mean heterogeneity number varied from 1.2 mm-10.6 mm in the evaluated cases. By selecting a field with a low mean heterogeneity number, target dose coverage and robustness against setup and range errors were improved. The developed method is simple, fast, accurate and applicable for beam angle selection in charged particle therapy with PBS.

A review of randomized controlled trials comparing the effectiveness of hand held computers with paper methods for data collection

PubMed Central

Lane, Shannon J; Heddle, Nancy M; Arnold, Emmy; Walker, Irwin

2006-01-01

Background Handheld computers are increasingly favoured over paper and pencil methods to capture data in clinical research. Methods This study systematically identified and reviewed randomized controlled trials (RCTs) that compared the two methods for self-recording and reporting data, and where at least one of the following outcomes was assessed: data accuracy; timeliness of data capture; and adherence to protocols for data collection. Results A comprehensive key word search of NLM Gateway's database yielded 9 studies fitting the criteria for inclusion. Data extraction was performed and checked by two of the authors. None of the studies included all outcomes. The results overall, favor handheld computers over paper and pencil for data collection among study participants but the data are not uniform for the different outcomes. Handheld computers appear superior in timeliness of receipt and data handling (four of four studies) and are preferred by most subjects (three of four studies). On the other hand, only one of the trials adequately compared adherence to instructions for recording and submission of data (handheld computers were superior), and comparisons of accuracy were inconsistent between five studies. Conclusion Handhelds are an effective alternative to paper and pencil modes of data collection; they are faster and were preferred by most users. PMID:16737535

Acceleration of FDTD mode solver by high-performance computing techniques.

PubMed

Han, Lin; Xi, Yanping; Huang, Wei-Ping

2010-06-21

A two-dimensional (2D) compact finite-difference time-domain (FDTD) mode solver is developed based on wave equation formalism in combination with the matrix pencil method (MPM). The method is validated for calculation of both real guided and complex leaky modes of typical optical waveguides against the bench-mark finite-difference (FD) eigen mode solver. By taking advantage of the inherent parallel nature of the FDTD algorithm, the mode solver is implemented on graphics processing units (GPUs) using the compute unified device architecture (CUDA). It is demonstrated that the high-performance computing technique leads to significant acceleration of the FDTD mode solver with more than 30 times improvement in computational efficiency in comparison with the conventional FDTD mode solver running on CPU of a standard desktop computer. The computational efficiency of the accelerated FDTD method is in the same order of magnitude of the standard finite-difference eigen mode solver and yet require much less memory (e.g., less than 10%). Therefore, the new method may serve as an efficient, accurate and robust tool for mode calculation of optical waveguides even when the conventional eigen value mode solvers are no longer applicable due to memory limitation.

Flow-guided sketch and accentuated-tone adjusting for pencil drawing generation

NASA Astrophysics Data System (ADS)

Li, Ruirui; Yang, Lei; Hu, Wei

2017-07-01

Pencil drawing is an important artistic style which is widely used in draft sketch and finished rendering. It is non-trivial if we can automatically generate the pencil drawing more precisely in order to ease the human efforts. In this paper, we propose flow-guided sketch and accentuated-tone adjusting techniques to transform the pencil drawing from natural images. This work is extended from the existing pencil drawing framework where authors combine sketch and tone together for penciling purpose. Through an edge tangent flow guided classification and convolution, we can obtain more coherent and smooth strokes, especially for portraits. In addition, we also introduce a hierarchical approach to generate strokes. According to saliency map, we can adjust the tone of images automatically. The experimental results indicate the generated toned pencil drawings by our approach are of fewer artifacts and could even solve the images with dark background

77 FR 53176 - Certain Cased Pencils From the People's Republic of China: Final Results of Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-31

... Determination To Revoke Order, in Part AGENCY: Import Administration, International Trade Administration... mechanical pencils, cosmetic pencils, pens, non-cased crayons (wax), pastels, charcoals, chalks, and pencils... turned wood encasing one-and-one half inches of sharpened lead on one end and a rubber eraser on the...

PRECISE ANGLE MONITOR BASED ON THE CONCEPT OF PENCIL-BEAM INTERFEROMETRY

DOE Office of Scientific and Technical Information (OSTI.GOV)

QIAN,S.; TAKACS,P.

2000-07-30

The precise angle monitoring is a very important metrology task for research, development and industrial applications. Autocollimator is one of the most powerful and widely applied instruments for small angle monitoring, which is based on the principle of geometric optics. In this paper the authors introduce a new precise angle monitoring system, Pencil-beam Angle Monitor (PAM), base on pencil beam interferometry. Its principle of operation is a combination of physical and geometrical optics. The angle calculation method is similar to the autocollimator. However, the autocollimator creates a cross image but the precise pencil-beam angle monitoring system produces an interference fringemore » on the focal plane. The advantages of the PAM are: high angular sensitivity, long-term stability character making angle monitoring over long time periods possible, high measurement accuracy in the order of sub-microradian, simultaneous measurement ability in two perpendicular directions or on two different objects, dynamic measurement possibility, insensitive to the vibration and air turbulence, automatic display, storage and analysis by use of the computer, small beam diameter making the alignment extremely easy and longer test distance. Some test examples are presented.« less

Refraction at a curved dielectric interface - Geometrical optics solution

NASA Technical Reports Server (NTRS)

Lee, S.-W.; Sheshadri, M. S.; Mittra, R.; Jamnejad, V.

1982-01-01

The transmission of a spherical or plane wave through an arbitrarily curved dielectric interface is solved by the geometrical optics theory. The transmitted field is proportional to the product of the conventional Fresnel's transmission coefficient and a divergence factor (DF), which describes the cross-sectional variation (convergence or divergence) of a ray pencil as the latter propagates in the transmitted region. The factor DF depends on the incident wavefront, the curvatures of the interface, and the relative indices of the two media. Explicit matrix formulas for calculating DF are given, and its physical significance is illustrated via examples.

Electronic versus paper-pencil methods for assessing chemotherapy-induced peripheral neuropathy.

PubMed

Knoerl, Robert; Gray, Evan; Stricker, Carrie; Mitchell, Sandra A; Kippe, Kelsey; Smith, Gloria; Dudley, William N; Lavoie Smith, Ellen M

2017-11-01

The aim of this study is to examine and compare with the validated, paper/pencil European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Chemotherapy-Induced Peripheral Neuropathy Scale (QLQ-CIPN20), the psychometric properties of three electronically administered patient reported outcome (PRO) measures of chemotherapy-induced peripheral neuropathy (CIPN): (1) the two neuropathy items from the National Cancer Institute's Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE), (2) the QLQ-CIPN20, and (3) the 0-10 Neuropathy Screening Question (NSQ). We employed a descriptive, cross-sectional design and recruited 25 women with breast cancer who were receiving neurotoxic chemotherapy at an academic hospital. Participants completed the paper/pencil QLQ-CIPN20 and electronic versions of the QLQ-CIPN20, PRO-CTCAE, and NSQ. Internal consistency reliability, intraclass correlation, and concurrent and discriminant validity analyses were conducted. The alpha coefficients for the electronic QLQ-CIPN20 sensory and motor subscales were 0.76 and 0.75. Comparison of the electronic and paper/pencil QLQ-CIPN20 subscales supported mode equivalence (intraclass correlation range >0.91). Participants who reported the presence of numbness/tingling via the single-item NSQ reported higher mean QLQ-CIPN20 sensory subscale scores (p < 0.001). PRO-CTCAE neuropathy severity and interference items correlated well with the QLQ-CIPN20 electronic and paper/pencil sensory (r = 0.76; r = 0.70) and motor (r = 0.55; r = 0.62) subscales, and with the NSQ (r = 0.72; r = 0.44). These data support the validity of the electronically administered PRO-CTCAE neuropathy items, NSQ, and QLQ-CIPN20 for neuropathy screening in clinical practice. The electronic and paper/pencil versions of the QLQ-CIPN can be used interchangeably based on evidence of mode equivalence.

Analytical linear energy transfer model including secondary particles: calculations along the central axis of the proton pencil beam

NASA Astrophysics Data System (ADS)

Marsolat, F.; De Marzi, L.; Pouzoulet, F.; Mazal, A.

2016-01-01

In proton therapy, the relative biological effectiveness (RBE) depends on various types of parameters such as linear energy transfer (LET). An analytical model for LET calculation exists (Wilkens’ model), but secondary particles are not included in this model. In the present study, we propose a correction factor, L sec, for Wilkens’ model in order to take into account the LET contributions of certain secondary particles. This study includes secondary protons and deuterons, since the effects of these two types of particles can be described by the same RBE-LET relationship. L sec was evaluated by Monte Carlo (MC) simulations using the GATE/GEANT4 platform and was defined by the ratio of the LET d distributions of all protons and deuterons and only primary protons. This method was applied to the innovative Pencil Beam Scanning (PBS) delivery systems and L sec was evaluated along the beam axis. This correction factor indicates the high contribution of secondary particles in the entrance region, with L sec values higher than 1.6 for a 220 MeV clinical pencil beam. MC simulations showed the impact of pencil beam parameters, such as mean initial energy, spot size, and depth in water, on L sec. The variation of L sec with these different parameters was integrated in a polynomial function of the L sec factor in order to obtain a model universally applicable to all PBS delivery systems. The validity of this correction factor applied to Wilkens’ model was verified along the beam axis of various pencil beams in comparison with MC simulations. A good agreement was obtained between the corrected analytical model and the MC calculations, with mean-LET deviations along the beam axis less than 0.05 keV μm-1. These results demonstrate the efficacy of our new correction of the existing LET model in order to take into account secondary protons and deuterons along the pencil beam axis.

On triangulations of the plane by pencils of conics. II

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lazareva, V B; Shelekhov, A M

2013-06-30

The present work continues our previous paper in which all possible triangulations of the plane using three pencils of circles were listed. In the present article we find all projectively distinct triangulations of the plane by pencils of conics that are obtained by projecting regular three-webs, cut out on a nondegenerate cubic surface by three pencils of planes, whose axes lie on this surface. Bibliography: 6 titles.

Pencil It in: Exploring the Feasibility of Hand-Drawn Pencil Electrochemical Sensors and Their Direct Comparison to Screen-Printed Electrodes

PubMed Central

Bernalte, Elena; Foster, Christopher W.; Brownson, Dale A.C.; Mosna, Morgane; Smith, Graham C.; Banks, Craig E.

2016-01-01

We explore the fabrication, physicochemical characterisation (SEM, Raman, EDX and XPS) and electrochemical application of hand-drawn pencil electrodes (PDEs) upon an ultra-flexible polyester substrate; investigating the number of draws (used for their fabrication), the pencil grade utilised (HB to 9B) and the electrochemical properties of an array of batches (i.e, pencil boxes). Electrochemical characterisation of the PDEs, using different batches of HB grade pencils, is undertaken using several inner- and outer-sphere redox probes and is critically compared to screen-printed electrodes (SPEs). Proof-of-concept is demonstrated for the electrochemical sensing of dopamine and acetaminophen using PDEs, which are found to exhibit competitive limits of detection (3σ) upon comparison to SPEs. Nonetheless, it is important to note that a clear lack of reproducibility was demonstrated when utilising these PDEs fabricated using the HB pencils from different batches. We also explore the suitability and feasibility of a pencil-drawn reference electrode compared to screen-printed alternatives, to see if one can draw the entire sensing platform. This article reports a critical assessment of these PDEs against that of its screen-printed competitors, questioning the overall feasibility of PDEs’ implementation as a sensing platform. PMID:27589815

Evaluating Tablet Computers as a Survey Tool in Rural Communities

PubMed Central

Newell, Steve M.; Logan, Henrietta L.; Guo, Yi; Marks, John G.; Shepperd, James A.

2015-01-01

Purpose Although tablet computers offer advantages in data collection over traditional paper-and-pencil methods, little research has examined whether the 2 formats yield similar responses, especially with underserved populations. We compared the 2 survey formats and tested whether participants’ responses to common health questionnaires or perceptions of usability differed by survey format. We also tested whether we could replicate established paper-and-pencil findings via tablet computer. Methods We recruited a sample of low-income community members living in the rural southern United States. Participants were 170 residents (black = 49%; white = 36%; other races and missing data = 15%) drawn from 2 counties meeting Florida’s state statutory definition of rural with 100 persons or fewer per square mile. We randomly assigned participants to complete scales (Center for Epidemiologic Studies Depression Inventory and Regulatory Focus Questionnaire) along with survey format usability ratings via paper-and-pencil or tablet computer. All participants rated a series of previously validated posters using a tablet computer. Finally, participants completed comparisons of the survey formats and reported survey format preferences. Findings Participants preferred using the tablet computer and showed no significant differences between formats in mean responses, scale reliabilities, or in participants’ usability ratings. Conclusions Overall, participants reported similar scales responses and usability ratings between formats. However, participants reported both preferring and enjoying responding via tablet computer more. Collectively, these findings are among the first data to show that tablet computers represent a suitable substitute among an underrepresented rural sample for paper-and-pencil methodology in survey research. PMID:25243953

Pencil drawn strain gauges and chemiresistors on paper.

PubMed

Lin, Cheng-Wei; Zhao, Zhibo; Kim, Jaemyung; Huang, Jiaxing

2014-01-22

Pencil traces drawn on print papers are shown to function as strain gauges and chemiresistors. Regular graphite/clay pencils can leave traces composed of percolated networks of fine graphite powders, which exhibit reversible resistance changes upon compressive or tensile deflections. Flexible toy pencils can leave traces that are essentially thin films of graphite/polymer composites, which show reversible changes in resistance upon exposure to volatile organic compounds due to absorption/desorption induced swelling/recovery of the polymer binders. Pencil-on-paper devices are low-cost, extremely simple and rapid to fabricate. They are light, flexible, portable, disposable, and do not generate potentially negative environmental impact during processing and device fabrication. One can envision many other types of pencil drawn paper electronic devices that can take on a great variety of form factors. Hand drawn devices could be useful in resource-limited or emergency situations. They could also lead to new applications integrating art and electronics.

SU-E-T-503: IMRT Optimization Using Monte Carlo Dose Engine: The Effect of Statistical Uncertainty.

PubMed

Tian, Z; Jia, X; Graves, Y; Uribe-Sanchez, A; Jiang, S

2012-06-01

With the development of ultra-fast GPU-based Monte Carlo (MC) dose engine, it becomes clinically realistic to compute the dose-deposition coefficients (DDC) for IMRT optimization using MC simulation. However, it is still time-consuming if we want to compute DDC with small statistical uncertainty. This work studies the effects of the statistical error in DDC matrix on IMRT optimization. The MC-computed DDC matrices are simulated here by adding statistical uncertainties at a desired level to the ones generated with a finite-size pencil beam algorithm. A statistical uncertainty model for MC dose calculation is employed. We adopt a penalty-based quadratic optimization model and gradient descent method to optimize fluence map and then recalculate the corresponding actual dose distribution using the noise-free DDC matrix. The impacts of DDC noise are assessed in terms of the deviation of the resulted dose distributions. We have also used a stochastic perturbation theory to theoretically estimate the statistical errors of dose distributions on a simplified optimization model. A head-and-neck case is used to investigate the perturbation to IMRT plan due to MC's statistical uncertainty. The relative errors of the final dose distributions of the optimized IMRT are found to be much smaller than those in the DDC matrix, which is consistent with our theoretical estimation. When history number is decreased from 108 to 106, the dose-volume-histograms are still very similar to the error-free DVHs while the error in DDC is about 3.8%. The results illustrate that the statistical errors in the DDC matrix have a relatively small effect on IMRT optimization in dose domain. This indicates we can use relatively small number of histories to obtain the DDC matrix with MC simulation within a reasonable amount of time, without considerably compromising the accuracy of the optimized treatment plan. This work is supported by Varian Medical Systems through a Master Research Agreement. © 2012 American Association of Physicists in Medicine.

An efficient method to determine double Gaussian fluence parameters in the eclipse™ proton pencil beam model.

PubMed

Shen, Jiajian; Liu, Wei; Stoker, Joshua; Ding, Xiaoning; Anand, Aman; Hu, Yanle; Herman, Michael G; Bues, Martin

2016-12-01

To find an efficient method to configure the proton fluence for a commercial proton pencil beam scanning (PBS) treatment planning system (TPS). An in-water dose kernel was developed to mimic the dose kernel of the pencil beam convolution superposition algorithm, which is part of the commercial proton beam therapy planning software, eclipse™ (Varian Medical Systems, Palo Alto, CA). The field size factor (FSF) was calculated based on the spot profile reconstructed by the in-house dose kernel. The workflow of using FSFs to find the desirable proton fluence is presented. The in-house derived spot profile and FSF were validated by a direct comparison with those calculated by the eclipse TPS. The validation included 420 comparisons of the FSFs from 14 proton energies, various field sizes from 2 to 20 cm and various depths from 20% to 80% of proton range. The relative in-water lateral profiles between the in-house calculation and the eclipse TPS agree very well even at the level of 10 -4 . The FSFs between the in-house calculation and the eclipse TPS also agree well. The maximum deviation is within 0.5%, and the standard deviation is less than 0.1%. The authors' method significantly reduced the time to find the desirable proton fluences of the clinical energies. The method is extensively validated and can be applied to any proton centers using PBS and the eclipse TPS.

Simultaneous quantification of arginine, alanine, methionine and cysteine amino acids in supplements using a novel bioelectro-nanosensor based on CdSe quantum dot/modified carbon nanotube hollow fiber pencil graphite electrode via Taguchi method.

PubMed

Hooshmand, Sara; Es'haghi, Zarrin

2017-11-30

A number of four amino acids have been simultaneously determined at CdSe quantum dot-modified/multi-walled carbon nanotube hollow fiber pencil graphite electrode in different bodybuilding supplements. CdSe quantum dots were synthesized and applied to construct a modified carbon nanotube hollow fiber pencil graphite electrode. FT-IR, TEM, XRD and EDAX methods were applied for characterization of the synthesized CdSe QDs. The electro-oxidation of arginine (Arg), alanine (Ala), methionine (Met) and cysteine (Cys) at the surface of the modified electrode was studied. Then the Taguchi's method was applied using MINITAB 17 software to find out the optimum conditions for the amino acids determination. Under the optimized conditions, the differential pulse (DP) voltammetric peak currents of Arg, Ala, Met and Cys increased linearly with their concentrations in the ranges of 0.287-33670μM and detection limits of 0.081, 0.158, 0.094 and 0.116μM were obtained for them, respectively. Satisfactory results were achieved for calibration and validation sets. The prepared modified electrode represents a very good resolution between the voltammetric peaks of the four amino acids which makes it suitable for the detection of each in presence of others in real samples. Copyright © 2017. Published by Elsevier B.V.

Near real-time automated dose restoration in IMPT to compensate for daily tissue density variations in prostate cancer

NASA Astrophysics Data System (ADS)

Jagt, Thyrza; Breedveld, Sebastiaan; van de Water, Steven; Heijmen, Ben; Hoogeman, Mischa

2017-06-01

Proton therapy is very sensitive to daily density changes along the pencil beam paths. The purpose of this study is to develop and evaluate an automated method for adaptation of IMPT plans to compensate for these daily tissue density variations. A two-step restoration method for ‘densities-of-the-day’ was created: (1) restoration of spot positions (Bragg peaks) by adapting the energy of each pencil beam to the new water equivalent path length; and (2) re-optimization of pencil beam weights by minimizing the dosimetric difference with the planned dose distribution, using a fast and exact quadratic solver. The method was developed and evaluated using 8-10 repeat CT scans of 10 prostate cancer patients. Experiments demonstrated that giving a high weight to the PTV in the re-optimization resulted in clinically acceptable restorations. For all scans we obtained V 95%  ⩾  98% and V 107%  ⩽  2%. For the bladder, the differences between the restored and the intended treatment plan were below  +2 Gy and  +2%-point. The rectum differences were below  +2 Gy and  +2%-point for 90% of the scans. In the remaining scans the rectum was filled with air, which partly overlapped with the PTV. The air cavity distorted the Bragg peak resulting in less favorable rectum doses.

A simple and sensitive methodology for voltammetric determination of valproic acid in human blood plasma samples using 3-aminopropyletriethoxy silane coated magnetic nanoparticles modified pencil graphite electrode.

PubMed

Zabardasti, Abedin; Afrouzi, Hossein; Talemi, Rasoul Pourtaghavi

2017-07-01

In this work, we have prepared a nano-material modified pencil graphite electrode for the sensing of valproic acid (VA) by immobilization 3-aminopropyletriethoxy silane coated magnetic nanoparticles (APTES-MNPs) on the pencil graphite surface (PGE). Electrochemical studies indicated that the APTES-MNPs efficiently increased the electron transfer kinetics between VA and the electrode and the free NH 2 groups of the APTES on the outer surface of magnetic nanoparticles can interact with carboxyl groups of VA. Based on this, we have proposed a sensitive, rapid and convenient electrochemical method for VA determination. Under the optimized conditions, the reduction peak current of VA is found to be proportional to its concentration in the range of 1.0 (±0.2) to 100.0 (±0.3) ppm with a detection limit of 0.4 (±0.1) ppm. The whole sensor fabrication process was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) methods with using [Fe(CN) 6 ] 3-/4- as an electrochemical redox indicator. The prepared modified electrode showed several advantages such as high sensitivity, selectivity, ease of preparation and good repeatability, reproducibility and stability. The proposed method was applied to determination of valproic acid in blood plasma samples and the obtained results were satisfactory accurate. Copyright © 2017. Published by Elsevier B.V.

Qualitative and quantitative outcomes of audience response systems as an educational tool in a plastic surgery residency program.

PubMed

Arneja, Jugpal S; Narasimhan, Kailash; Bouwman, David; Bridge, Patrick D

2009-12-01

In-training evaluations in graduate medical education have typically been challenging. Although the majority of standardized examination delivery methods have become computer-based, in-training examinations generally remain pencil-paper-based, if they are performed at all. Audience response systems present a novel way to stimulate and evaluate the resident-learner. The purpose of this study was to assess the outcomes of audience response systems testing as compared with traditional testing in a plastic surgery residency program. A prospective 1-year pilot study of 10 plastic surgery residents was performed using audience response systems-delivered testing for the first half of the academic year and traditional pencil-paper testing for the second half. Examination content was based on monthly "Core Quest" curriculum conferences. Quantitative outcome measures included comparison of pretest and posttest and cumulative test scores of both formats. Qualitative outcomes from the individual participants were obtained by questionnaire. When using the audience response systems format, pretest and posttest mean scores were 67.5 and 82.5 percent, respectively; using traditional pencil-paper format, scores were 56.5 percent and 79.5 percent. A comparison of the cumulative mean audience response systems score (85.0 percent) and traditional pencil-paper score (75.0 percent) revealed statistically significantly higher scores with audience response systems (p = 0.01). Qualitative outcomes revealed increased conference enthusiasm, greater enjoyment of testing, and no user difficulties with the audience response systems technology. The audience response systems modality of in-training evaluation captures participant interest and reinforces material more effectively than traditional pencil-paper testing does. The advantages include a more interactive learning environment, stimulation of class participation, immediate feedback to residents, and immediate tabulation of results for the educator. Disadvantages include start-up costs and lead-time preparation.

SU-E-T-188: Film Dosimetry Verification of Monte Carlo Generated Electron Treatment Plans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Enright, S; Asprinio, A; Lu, L

2014-06-01

Purpose: The purpose of this study was to compare dose distributions from film measurements to Monte Carlo generated electron treatment plans. Irradiation with electrons offers the advantages of dose uniformity in the target volume and of minimizing the dose to deeper healthy tissue. Using the Monte Carlo algorithm will improve dose accuracy in regions with heterogeneities and irregular surfaces. Methods: Dose distributions from GafChromic{sup ™} EBT3 films were compared to dose distributions from the Electron Monte Carlo algorithm in the Eclipse{sup ™} radiotherapy treatment planning system. These measurements were obtained for 6MeV, 9MeV and 12MeV electrons at two depths. Allmore » phantoms studied were imported into Eclipse by CT scan. A 1 cm thick solid water template with holes for bonelike and lung-like plugs was used. Different configurations were used with the different plugs inserted into the holes. Configurations with solid-water plugs stacked on top of one another were also used to create an irregular surface. Results: The dose distributions measured from the film agreed with those from the Electron Monte Carlo treatment plan. Accuracy of Electron Monte Carlo algorithm was also compared to that of Pencil Beam. Dose distributions from Monte Carlo had much higher pass rates than distributions from Pencil Beam when compared to the film. The pass rate for Monte Carlo was in the 80%–99% range, where the pass rate for Pencil Beam was as low as 10.76%. Conclusion: The dose distribution from Monte Carlo agreed with the measured dose from the film. When compared to the Pencil Beam algorithm, pass rates for Monte Carlo were much higher. Monte Carlo should be used over Pencil Beam for regions with heterogeneities and irregular surfaces.« less

A study of lateral fall-off (penumbra) optimisation for pencil beam scanning (PBS) proton therapy

NASA Astrophysics Data System (ADS)

Winterhalter, C.; Lomax, A.; Oxley, D.; Weber, D. C.; Safai, S.

2018-01-01

The lateral fall-off is crucial for sparing organs at risk in proton therapy. It is therefore of high importance to minimize the penumbra for pencil beam scanning (PBS). Three optimisation approaches are investigated: edge-collimated uniformly weighted spots (collimation), pencil beam optimisation of uncollimated pencil beams (edge-enhancement) and the optimisation of edge collimated pencil beams (collimated edge-enhancement). To deliver energies below 70 MeV, these strategies are evaluated in combination with the following pre-absorber methods: field specific fixed thickness pre-absorption (fixed), range specific, fixed thickness pre-absorption (automatic) and range specific, variable thickness pre-absorption (variable). All techniques are evaluated by Monte Carlo simulated square fields in a water tank. For a typical air gap of 10 cm, without pre-absorber collimation reduces the penumbra only for water equivalent ranges between 4-11 cm by up to 2.2 mm. The sharpest lateral fall-off is achieved through collimated edge-enhancement, which lowers the penumbra down to 2.8 mm. When using a pre-absorber, the sharpest fall-offs are obtained when combining collimated edge-enhancement with a variable pre-absorber. For edge-enhancement and large air gaps, it is crucial to minimize the amount of material in the beam. For small air gaps however, the superior phase space of higher energetic beams can be employed when more material is used. In conclusion, collimated edge-enhancement combined with the variable pre-absorber is the recommended setting to minimize the lateral penumbra for PBS. Without collimator, it would be favourable to use a variable pre-absorber for large air gaps and an automatic pre-absorber for small air gaps.

76 FR 11267 - Cased Pencils From China

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-01

... China AGENCY: United States International Trade Commission. ACTION: Scheduling of an expedited five-year review concerning the antidumping duty order on cased pencils from China. SUMMARY: The Commission hereby... cased pencils from China would be likely to lead to continuation or recurrence of material injury within...

Comparisons among tools, surface orientation, and pencil grasp for children 23 months of age.

PubMed

Yakimishyn, Janet E; Magill-Evans, Joyce

2002-01-01

The purpose of this study was to determine whether writing tool type and angle of writing surface affect grasp. Fifty-one children 23 to 24 months of age who were typically developing drew with a primary marker, colored pencil, and small piece of crayon on a table and an easel. The marker and pencil were presented pointing left, right, and toward the child. The order of writing tool presentation was counterbalanced. Grasps were scored with a 5-point rating system and analyzed with dependent t tests. Children used a more mature grasp when drawing with a piece of crayon than with a pencil. No difference in grasp maturity was found when using a pencil compared with a marker. A more mature grasp when drawing on the easel compared with the table was used with the crayon but not with the marker or pencil. Results imply that a short writing tool combined with a vertical surface can influence the grasp of young children.

A binder-free wet chemical synthesis approach to decorate nanoflowers of bismuth oxide on Ni-foam for fabricating laboratory scale potential pencil-type asymmetric supercapacitor device.

PubMed

Shinde, N M; Xia, Qi Xun; Yun, Je Moon; Singh, Saurabh; Mane, Rajaram S; Kim, Kwang-Ho

2017-05-23

The present study involves the synthesis of a bismuth oxide (Bi 2 O 3 ) electrode consisting of an arranged nano-platelets for evolving a flower-type surface appearance on nickel-foam (Bi 2 O 3 -Ni-F) by a simple, inexpensive, binder-free and one-step chemical bath deposition (CBD) method, popularly known as a wet chemical method. The as-prepared Bi 2 O 3 on Ni-foam, as an electrode material, demonstrates 557 F g -1 specific capacitance (SC, at 1 mA cm -2 ), of which 85% is retained even after 2000 cycles. With specific power density of 500 kW kg -1 , the Bi 2 O 3 -Ni-F electrode documents a specific energy density of 80 Wh kg -1 . Furthermore, a portable asymmetric supercapacitor device, i.e. a pencil-type cell consisting of Bi 2 O 3 -Ni-F as an anode and graphite as a cathode in 6 M KOH aqueous electrolyte solution, confirms 11 Wh kg -1 and 720 kW kg -1 specific energy and specific power densities, respectively. An easy and a simple synthesis approach for manufacturing a portable laboratory scale pencil-type supercapacitor device is a major outcome of this study, which can also be applied for ternary and quaternary metal oxides for recording an enhanced performance. In addition, we presented a demonstration of lighting a light emitting diode (LED) using a home-made pencil-type supercapacitor device which, finally, has confirmed the scaling and technical potentiality of Bi 2 O 3 -Ni-F in energy storage devices.

Experimental verification of gain drop due to general ion recombination for a carbon-ion pencil beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tansho, Ryohei, E-mail: r-tansho@nirs.go.jp; Furukawa, Takuji; Hara, Yousuke

Purpose: Accurate dose measurement in radiotherapy is critically dependent on correction for gain drop, which is the difference of the measured current from the ideal saturation current due to general ion recombination. Although a correction method based on the Boag theory has been employed, the theory assumes that ionized charge density in an ionization chamber (IC) is spatially uniform throughout the irradiation volume. For particle pencil beam scanning, however, the charge density is not uniform, because the fluence distribution of a pencil beam is not uniform. The aim of this study was to verify the effect of the nonuniformity ofmore » ionized charge density on the gain drop due to general ion recombination. Methods: The authors measured the saturation curve, namely, the applied voltage versus measured current, using a large plane-parallel IC and 24-channel parallel-plate IC with concentric electrodes. To verify the effect of the nonuniform ionized charge density on the measured saturation curve, the authors calculated the saturation curve using a method which takes into account the nonuniform ionized charge density and compared it with the measured saturation curves. Results: Measurement values of the different saturation curves in the different channels of the concentric electrodes differed and were consistent with the calculated values. The saturation curves measured by the large plane-parallel IC were also consistent with the calculation results, including the estimation error of beam size and of setup misalignment. Although the impact of the nonuniform ionized charge density on the gain drop was clinically negligible with the conventional beam intensity, it was expected that the impact would increase with higher ionized charge density. Conclusions: For pencil beam scanning, the assumption of the conventional Boag theory is not valid. Furthermore, the nonuniform ionized charge density affects the prediction accuracy of gain drop when the ionized charge density is increased by a higher dose rate and/or lower beam size.« less

SU-E-T-549: A Combinatorial Optimization Approach to Treatment Planning with Non-Uniform Fractions in Intensity Modulated Proton Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Papp, D; Unkelbach, J

2014-06-01

Purpose: Non-uniform fractionation, i.e. delivering distinct dose distributions in two subsequent fractions, can potentially improve outcomes by increasing biological dose to the target without increasing dose to healthy tissues. This is possible if both fractions deliver a similar dose to normal tissues (exploit the fractionation effect) but high single fraction doses to subvolumes of the target (hypofractionation). Optimization of such treatment plans can be formulated using biological equivalent dose (BED), but leads to intractable nonconvex optimization problems. We introduce a novel optimization approach to address this challenge. Methods: We first optimize a reference IMPT plan using standard techniques that deliversmore » a homogeneous target dose in both fractions. The method then divides the pencil beams into two sets, which are assigned to either fraction one or fraction two. The total intensity of each pencil beam, and therefore the physical dose, remains unchanged compared to the reference plan. The objectives are to maximize the mean BED in the target and to minimize the mean BED in normal tissues, which is a quadratic function of the pencil beam weights. The optimal reassignment of pencil beams to one of the two fractions is formulated as a binary quadratic optimization problem. A near-optimal solution to this problem can be obtained by convex relaxation and randomized rounding. Results: The method is demonstrated for a large arteriovenous malformation (AVM) case treated in two fractions. The algorithm yields a treatment plan, which delivers a high dose to parts of the AVM in one of the fractions, but similar doses in both fractions to the normal brain tissue adjacent to the AVM. Using the approach, the mean BED in the target was increased by approximately 10% compared to what would have been possible with a uniform reference plan for the same normal tissue mean BED.« less

No-cost manual method for preparation of tissue microarrays having high quality comparable to semiautomated methods.

PubMed

Foda, Abd Al-Rahman Mohammad

2013-05-01

Manual tissue microarray (TMA) construction had been introduced to avoid the high cost of automated and semiautomated techniques. The cheapest and simplest technique for constructing manual TMA was that of using mechanical pencil tips. This study was carried out to modify this method, aiming to raise its quality to reach that of expensive ones. Some modifications were introduced to Shebl's technique. Two conventional mechanical pencil tips of different diameters were used to construct the recipient blocks. A source of mild heat was used, and blocks were incubated at 38°C overnight. With our modifications, 3 high-density TMA blocks were constructed. We successfully performed immunostaining without substantial tissue loss. Our modifications increased the number of cores per block and improved the stability of the cores within the paraffin block. This new, modified technique is a good alternative for expensive machines in many laboratories.

The Art of Pencil Practice.

ERIC Educational Resources Information Center

Clowes, Robert F.

1997-01-01

Proposes that music teachers should have their students practice during those spare moments during the school day by using a pencil instead of their actual instrument. Explains that students can practice chromatic fingerings, memorize short pieces of music, or review scales. Gives instructions on how to "pencil practice." (CMK)

Automated Psychological Testing: Method of Administration, Need for Approval, and Measures of Anxiety.

ERIC Educational Resources Information Center

Davis, Caroline; Cowles, Michael

1989-01-01

Computerized and paper-and-pencil versions of four standard personality inventories administered to 147 undergraduates were compared for: (1) test-retest reliability; (2) scores; (3) trait anxiety; (4) interaction between method and social desirability; and (5) preferences concerning method of testing. Doubts concerning the efficacy of…

Comparing data collected by computerized and written surveys for adolescence health research.

PubMed

Wu, Ying; Newfield, Susan A

2007-01-01

This study assessed whether data-collection formats, computerized versus paper-and-pencil, affect response patterns and descriptive statistics for adolescent health assessment surveys. Youth were assessed as part of a health risk reduction program. Baseline data from 1131 youth were analyzed. Participants completed the questionnaire either by computer (n = 390) or by paper-and-pencil (n = 741). The rate of returned surveys meeting inclusion requirements was 90.6% and did not differ by methods. However, the computerized method resulted in significantly less incompleteness but more identical responses. Multiple regression indicated that the survey methods did not contribute to problematic responses. The two survey methods yielded similar scale internal reliability and descriptive statistics for behavioral and psychological outcomes, although the computerized method elicited higher reports of some risk items such as carrying a knife, beating up a person, selling drugs, and delivering drugs. Overall, the survey method did not produce a significant difference in outcomes. This provides support for program personnel selecting survey methods based on study goals with confidence that the method of administration will not have a significant impact on the outcome.

Use of Weighted Pencils to Improve Handwriting Legibility

ERIC Educational Resources Information Center

Brown, Michelle J.

2017-01-01

Several therapeutic strategies and approaches are used to facilitate handwriting skills in children with illegible writing. One strategy is weighted pencils; however, there is little empirical evidence of the strategy's efficacy. In case scenarios of three children who were unable to form letters, weighted pencils improved their handwriting, and a…

The International Pencil: Elementary Level Unit on Global Interdependence.

ERIC Educational Resources Information Center

Wolken, Lawrence C.

1984-01-01

The production of an American pencil is the result of complex interactions involving many people, places, and resources. Learning activities dealing with the making of a pencil that will help students learn about global interdependence are described. The activities can be adapted to fit any elementary grade level. (RM)

Life Cycle of a Pencil.

ERIC Educational Resources Information Center

Reeske, Mike

2000-01-01

Explains a project called "Life Cycle of a Pencil" which was developed by the National Science Teachers Association (NSTA) and the U.S. Environmental Protection Agency (USEPA). Describes the life cycle of a pencil in stages starting from the first stage of design to the sixth stage of product disposal. (YDS)

Radial secondary electron dose profiles and biological effects in light-ion beams based on analytical and Monte Carlo calculations using distorted wave cross sections.

PubMed

Wiklund, Kristin; Olivera, Gustavo H; Brahme, Anders; Lind, Bengt K

2008-07-01

To speed up dose calculation, an analytical pencil-beam method has been developed to calculate the mean radial dose distributions due to secondary electrons that are set in motion by light ions in water. For comparison, radial dose profiles calculated using a Monte Carlo technique have also been determined. An accurate comparison of the resulting radial dose profiles of the Bragg peak for (1)H(+), (4)He(2+) and (6)Li(3+) ions has been performed. The double differential cross sections for secondary electron production were calculated using the continuous distorted wave-eikonal initial state method (CDW-EIS). For the secondary electrons that are generated, the radial dose distribution for the analytical case is based on the generalized Gaussian pencil-beam method and the central axis depth-dose distributions are calculated using the Monte Carlo code PENELOPE. In the Monte Carlo case, the PENELOPE code was used to calculate the whole radial dose profile based on CDW data. The present pencil-beam and Monte Carlo calculations agree well at all radii. A radial dose profile that is shallower at small radii and steeper at large radii than the conventional 1/r(2) is clearly seen with both the Monte Carlo and pencil-beam methods. As expected, since the projectile velocities are the same, the dose profiles of Bragg-peak ions of 0.5 MeV (1)H(+), 2 MeV (4)He(2+) and 3 MeV (6)Li(3+) are almost the same, with about 30% more delta electrons in the sub keV range from (4)He(2+)and (6)Li(3+) compared to (1)H(+). A similar behavior is also seen for 1 MeV (1)H(+), 4 MeV (4)He(2+) and 6 MeV (6)Li(3+), all classically expected to have the same secondary electron cross sections. The results are promising and indicate a fast and accurate way of calculating the mean radial dose profile.

76 FR 2337 - Certain Cased Pencils From the People's Republic of China: Preliminary Results and Partial...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-13

... has autonomy from the government in making decisions regarding the selection of management; and (4... Financial Statistics. When relying on prices of imports into India as surrogate values, we have disregarded... the 2006-2007 financial statement of Triveni Pencils Ltd. (``Triveni''), an Indian producer of pencils...

All about the Pencil

ERIC Educational Resources Information Center

Stevens, Sue

2006-01-01

This article presents the history of pencils. Graphite, which is the main component that makes pencils write, was first discovered to be useful in marking the sheep of local farmers in Borrowdale, England in 1954. This graphite left a much darker mark than lead, which made it ideal for use by writers and artists. Around, 1795, Nicolas-Jacques…

Dry writing of highly conductive electrodes on papers by using silver nanoparticle-graphene hybrid pencils.

PubMed

Park, Jun-Ho; Park, Myung-Joo; Lee, Jang-Sik

2017-01-05

The development of paper electronics would enable realization of extremely cheap devices for portable, disposable, and environmentally-benign electronics. Here, we propose a simple dry-writing tool similar to a pencil, which can be used to draw electrically conducting lines on paper for use in paper-based electronic devices. The fabricated pencil is composed of silver nanoparticles decorated on graphene layers to construct layered hybrid nanostructures. This pencil can draw highly conductive lines that are flexible and foldable on conventional papers. Electrodes drawn using this pencil on conventional copy paper are stable during repetitive mechanical folding and highly resistant to moisture/chemicals. This pencil can draw a conductive line where its resistance can be tuned by changing the amount of nanoparticles. A nonvolatile memory device is realized on papers by hand written lines with different resistance. All memory elements are composed of carbons on papers, so complete data security can be achieved by burning the memory papers. This work will provide a new opportunity to fabricate electronic devices on real papers with good conductivity as well as robust mechanical/chemical stability.

The Analysis of Discourse as Evaluation of Productive Thinking.

ERIC Educational Resources Information Center

Tripp, D. H.

This paper provides a thorough description of a method of analyzing and scoring group discussions from a particular point of view. After discussing shortcomings of traditional methods of reporting data from group discussions and problems inherent in the use of paper-and-pencil creativity tests, the author describes a method which was developed as…

The Dynamics of DNA Sequencing.

ERIC Educational Resources Information Center

Morvillo, Nancy

1997-01-01

Describes a paper-and-pencil activity that helps students understand DNA sequencing and expands student understanding of DNA structure, replication, and gel electrophoresis. Appropriate for advanced biology students who are familiar with the Sanger method. (DDR)

Measuring Management Abilities and Motivation.

ERIC Educational Resources Information Center

Howard, Ann

1983-01-01

The complexity of managerial abilities and motivation is displayed in the assessment center method, where judgments depend on a comprehensive package of such techniques as paper-and-pencil tests, interviews, simulations, and projective tests. (Author)

76 FR 4285 - Certain Cased Pencils From the People's Republic of China: Notice of Court Decision Not in...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-25

... the People's Republic of China: Notice of Court Decision Not in Harmony With Final Results of... respondents China First Pencil Co., Ltd. (``China First'') and Shanghai Three Star Stationery Industry Corp.... (``SFTC'') pursuant to the CIT's remand order in China First Pencil Co., Ltd. v. United States, 721 F...

77 FR 42276 - Certain Cased Pencils From the People's Republic of China: Initiation and Preliminary Results of...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-18

... scope of the order are mechanical pencils, cosmetic pencils, pens, non-cased crayons (wax), pastels... circumference, composed of turned wood encasing one-and-one half inches of sharpened lead on one end and a... Circumstances Review and Determination to Revoke Order in Part, 74 FR 8506 (February 25, 2009) (retroactively...

Measuring Vitamin C Content of Commercial Orange Juice Using a Pencil Lead Electrode

ERIC Educational Resources Information Center

King, David; Friend, Jeffrey; Kariuki, James

2010-01-01

A pencil lead successfully served as an electrode for the determination of ascorbic acid in commercial orange juice. Cyclic voltammetry was used as an electrochemical probe to measure the current produced from the oxidation of ascorbic acid with a variety of electrodes. The data demonstrate that the less expensive pencil lead electrode gives…

78 FR 54452 - Certain Cased Pencils From the People's Republic of China: Rescission of Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-04

... the People's Republic of China: Rescission of Antidumping Duty Administrative Review; 2011-2012 AGENCY... certain cased pencils (pencils) from the People's Republic of China (PRC) for the period December 1, 2011, through November 30, 2012, based on the withdrawal of the review request by one company and on the...

Adaptation from Paper-Pencil to Web-Based Administration of a Parent-Completed Developmental Questionnaire for Young Children

ERIC Educational Resources Information Center

Yovanoff, Paul; Squires, Jane; McManus, Suzanne

2013-01-01

Adapting traditional paper-pencil instruments to computer-based environments has received considerable attention from the research community due to the possible administration mode effects on obtained measures. When differences due to mode of completion (i.e., paper-pencil, computer-based) are present, threats to measurement validity are posed. In…

DOE Office of Scientific and Technical Information (OSTI.GOV)

St James, S; Bloch, C; Saini, J

Purpose: Proton pencil beam scanning is used clinically across the United States. There are no current guidelines on tolerances for daily QA specific to pencil beam scanning, specifically related to the individual spot properties (spot width). Using a stochastic method to determine tolerances has the potential to optimize tolerances on individual spots and decrease the number of false positive failures in daily QA. Individual and global spot tolerances were evaluated. Methods: As part of daily QA for proton pencil beam scanning, a field of 16 spots (corresponding to 8 energies) is measured using an array of ion chambers (Matrixx, IBA).more » Each individual spot is fit to two Gaussian functions (x,y). The spot width (σ) in × and y are recorded (32 parameters). Results from the daily QA were retrospectively analyzed for 100 days of data. The deviations of the spot widths were histogrammed and fit to a Gaussian function. The stochastic spot tolerance was taken to be the mean ± 3σ. Using these results, tolerances were developed and tested against known deviations in spot width. Results: The individual spot tolerances derived with the stochastic method decreased in 30/32 instances. Using the previous tolerances (± 20% width), the daily QA would have detected 0/20 days of the deviation. Using a tolerance of any 6 spots failing the stochastic tolerance, 18/20 days of the deviation would have been detected. Conclusion: Using a stochastic method we have been able to decrease daily tolerances on the spot widths for 30/32 spot widths measured. The stochastic tolerances can lead to detection of deviations that previously would have been picked up on monthly QA and missed by daily QA. This method could be easily extended for evaluation of other QA parameters in proton spot scanning.« less

Solution-processed nanocrystalline PbS on paper substrate with pencil traced electrodes as visible photodetector

NASA Astrophysics Data System (ADS)

Vankhade, Dhaval; Chaudhuri, Tapas K.

2018-04-01

Paper-based PbS photodetector sensitive in the visible spectrum is reported. Nanocrystalline PbS-on-paper devices are fabricated by a spin coating method on white paper (300 GSM) from a methanolic precursor solution. Photodetector cells of gap 0.2 cm and length 0.5 cm are prepared by drawing contacts by monolithic cretacolor 8B pencil. X-ray diffractometer confirmed the deposition of nanocrystalline PbS films with 14 nm crystallites. The SEM illustrated the uniform coating of nanocrystalline PbS thin films on cellulose fibres of papers having an average thickness of fibres are 10 µm. The linear J-V characteristics in dark and under illumination of light using graphite trace on nanocrystalline PbS-on-paper shows good ohmic contact. The resistivity of pencil trace is 30 Ω.cm. Spectral response measurements of photodetector reveal the excellent sensitivity from 400 to 700 nm with a peak at 550 nm. The best responsivity anddetectivity are 0.7 A/W and 1.4 × 1012 Jones respectively. These paper-based low-cost photodetectors devices have fast photoresponse and recovery without baseline deviation.

Dynamic splitting of Gaussian pencil beams in heterogeneity-correction algorithms for radiotherapy with heavy charged particles.

PubMed

Kanematsu, Nobuyuki; Komori, Masataka; Yonai, Shunsuke; Ishizaki, Azusa

2009-04-07

The pencil-beam algorithm is valid only when elementary Gaussian beams are small enough compared to the lateral heterogeneity of a medium, which is not always true in actual radiotherapy with protons and ions. This work addresses a solution for the problem. We found approximate self-similarity of Gaussian distributions, with which Gaussian beams can split into narrower and deflecting daughter beams when their sizes have overreached lateral heterogeneity in the beam-transport calculation. The effectiveness was assessed in a carbon-ion beam experiment in the presence of steep range compensation, where the splitting calculation reproduced a detour effect amounting to about 10% in dose or as large as the lateral particle disequilibrium effect. The efficiency was analyzed in calculations for carbon-ion and proton radiations with a heterogeneous phantom model, where the beam splitting increased computing times by factors of 4.7 and 3.2. The present method generally improves the accuracy of the pencil-beam algorithm without severe inefficiency. It will therefore be useful for treatment planning and potentially other demanding applications.

Paper-and-Pencil Programming Strategy toward Computational Thinking for Non-Majors: Design Your Solution

ERIC Educational Resources Information Center

Kim, Byeongsu; Kim, Taehun; Kim, Jonghoon

2013-01-01

The paper-and-pencil programming strategy (PPS) is a way of representing an idea logically by any representation that can be created using paper and pencil. It was developed for non-computer majors to improve their understanding and use of computational thinking and increase interest in learning computer science. A total of 110 non-majors in their…

76 FR 12323 - Certain Cased Pencils From the People's Republic of China: Final Results of the Expedited Third...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-07

... duty order would be likely to lead to continuation or recurrence of dumping at the margins identified... of Amended Final Determination of Sales at Less Than Fair Value and Amended Antidumping Duty Order in...''). Specifically excluded from the scope of the order are mechanical pencils, cosmetic pencils, pens, non-cased...

Designing and Using Software Tools for Educational Purposes: FLAT, a Case Study

ERIC Educational Resources Information Center

Castro-Schez, J. J.; del Castillo, E.; Hortolano, J.; Rodriguez, A.

2009-01-01

Educational software tools are considered to enrich teaching strategies, providing a more compelling means of exploration and feedback than traditional blackboard methods. Moreover, software simulators provide a more motivating link between theory and practice than pencil-paper methods, encouraging active and discovery learning in the students.…

Beyond Pascal's Triangle

ERIC Educational Resources Information Center

Minor, Darrell P.

2005-01-01

In "Beyond Pascals Triangle" the author demonstrates ways of using "Pascallike" triangles to expand polynomials raised to powers in a fairly quick and easy fashion. The recursive method could easily be implemented within a spreadsheet, or simply by using paper and pencil. An explanation of why the method works follows the several examples that are…

Cognitive Changes among Institutionalized Elderly People

ERIC Educational Resources Information Center

Navarro, Jose I.; Menacho, Inmaculada; Alcalde, Concepcion; Marchena, Esperanza; Ruiz, Gonzalo; Aguilar, Manuel

2009-01-01

The efficiency of different cognitive training procedures in elderly people was studied. Two types of methods to train cognitive and memory functions were compared. One method was based on new technologies and the other one on pencil-and-paper activities. Thirty-six elderly institutionalized people aged 68-94 were trained. Quantitative and memory…

Problems with small area surveys: lensing covariance of supernova distance measurements.

PubMed

Cooray, Asantha; Huterer, Dragan; Holz, Daniel E

2006-01-20

While luminosity distances from type Ia supernovae (SNe) are a powerful probe of cosmology, the accuracy with which these distances can be measured is limited by cosmic magnification due to gravitational lensing by the intervening large-scale structure. Spatial clustering of foreground mass leads to correlated errors in SNe distances. By including the full covariance matrix of SNe, we show that future wide-field surveys will remain largely unaffected by lensing correlations. However, "pencil beam" surveys, and those with narrow (but possibly long) fields of view, can be strongly affected. For a survey with 30 arcmin mean separation between SNe, lensing covariance leads to a approximately 45% increase in the expected errors in dark energy parameters.

High-resolution simulation of deep pencil beam surveys - analysis of quasi-periodicity

NASA Astrophysics Data System (ADS)

Weiss, A. G.; Buchert, T.

1993-07-01

We carry out pencil beam constructions in a high-resolution simulation of the large-scale structure of galaxies. The initial density fluctuations are taken to have a truncated power spectrum. All the models have {OMEGA} = 1. As an example we present the results for the case of "Hot-Dark-Matter" (HDM) initial conditions with scale-free n = 1 power index on large scales as a representative of models with sufficient large-scale power. We use an analytic approximation for particle trajectories of a self-gravitating dust continuum and apply a local dynamical biasing of volume elements to identify luminous matter in the model. Using this method, we are able to resolve formally a simulation box of 1200h^-1^ Mpc (e.g. for HDM initial conditions) down to the scale of galactic halos using 2160^3^ particles. We consider this as the minimal resolution necessary for a sensible simulation of deep pencil beam data. Pencil beam probes are taken for a given epoch using the parameters of observed beams. In particular, our analysis concentrates on the detection of a quasi-periodicity in the beam probes using several different methods. The resulting beam ensembles are analyzed statistically using number distributions, pair-count histograms, unnormalized pair-counts, power spectrum analysis and trial-period folding. Periodicities are classified according to their significance level in the power spectrum of the beams. The simulation is designed for application to parameter studies which prepare future observational projects. We find that a large percentage of the beams show quasi- periodicities with periods which cluster at a certain length scale. The periods found range between one and eight times the cutoff length in the initial fluctuation spectrum. At significance levels similar to those of the data of Broadhurst et al. (1990), we find about 15% of the pencil beams to show periodicities, about 30% of which are around the mean separation of rich clusters, while the distribution of scales reaches values of more than 200h^-1^ Mpc. The detection of periodicities larger than the typical void size must not be due to missing of "walls" (like the so called "Great Wall" seen in the CfA catalogue of galaxies), but can be due to different clustering properties of galaxies along the beams.

WE-D-17A-02: Evaluation of a Two-Dimensional Optical Dosimeter On Measuring Lateral Profiles of Proton Pencil Beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsi, W; Lee, T; Schultz, T

Purpose: To evaluate the accuracy of a two-dimensional optical dosimeter on measuring lateral profiles for spots and scanned fields of proton pencil beams. Methods: A digital camera with a color image senor was utilized to image proton-induced scintillations on Gadolinium-oxysulfide phosphor reflected by a stainless-steel mirror. Intensities of three colors were summed for each pixel with proper spatial-resolution calibration. To benchmark this dosimeter, the field size and penumbra for 100mm square fields of singleenergy pencil-scan protons were measured and compared between this optical dosimeter and an ionization-chamber profiler. Sigma widths of proton spots in air were measured and compared betweenmore » this dosimeter and a commercial optical dosimeter. Clinical proton beams with ranges between 80 mm and 300 mm at CDH proton center were used for this benchmark. Results: Pixel resolutions vary 1.5% between two perpendicular axes. For a pencil-scan field with 302 mm range, measured field sizes and penumbras between two detection systems agreed to 0.5 mm and 0.3 mm, respectively. Sigma widths agree to 0.3 mm between two optical dosimeters for a proton spot with 158 mm range; having widths of 5.76 mm and 5.92 mm for X and Y axes, respectively. Similar agreements were obtained for others beam ranges. This dosimeter was successfully utilizing on mapping the shapes and sizes of proton spots at the technical acceptance of McLaren proton therapy system. Snow-flake spots seen on images indicated the image sensor having pixels damaged by radiations. Minor variations in intensity between different colors were observed. Conclusions: The accuracy of our dosimeter was in good agreement with other established devices in measuring lateral profiles of pencil-scan fields and proton spots. A precise docking mechanism for camera was designed to keep aligned optical path while replacing damaged image senor. Causes for minor variations between emitted color lights will be investigated.« less

Psychological Assessment via the Internet: A Reliability and Validity Study of Online (vs Paper-and-Pencil) Versions of the General Health Questionnaire-28 (GHQ-28) and the Symptoms Check-List-90-Revised (SCL-90-R)

PubMed Central

Jordán, Carlos M; Díaz, Marta I; Comeche, María I; Ortega, José

2007-01-01

Background Internet psychology services are rapidly increasing and that implies online assessment. To guarantee the results of these new online evaluation procedures, it is necessary to have reliable and valid assessment tools. Objective In this work we analyzed the online versions of two popular psychopathology screening questionnaires: the General Health Questionnaire-28 (GHQ-28) and the Symptoms Check-List-90-Revised (SCL-90-R). Methods A total of 185 psychology students were recruited from two universities in Madrid, Spain. All of them had Internet access at home. A test-retest situation and factorial analysis were used to generate reliability and validity data. Both paper-and-pencil questionnaires (test) and their online versions (retest) were completed by 100 participants (median gap = 17 days). Results Results suggest that both online questionnaires were fairly equivalent to their paper-and-pencil versions, with higher reliability values for the SCL-90-R. Factorial analysis tended to reproduce the structure shown in former investigations of both questionnaires, replicating the four-factor structure of the GHQ-28 but failing to do so with the nine-factor structure of the SCL-90-R. Instead, a large unrotated factor appeared. Conclusions Further research should be carried out to confirm these data, but our work supports the online use of both assessment tools. The psychometric properties of the online version of GHQ-28 is similar to the paper-and-pencil and we can recommend its utilization in a Web environment. In contrast, SCL-90-R can only be recommended as a global index for psychological distress, using the Global Severity Index (GSI), not necessarily its subscales; and it should be considered that the online scores were lower than the ones with the paper-and-pencil version. PMID:17478411

Iterated unscented Kalman filter for phase unwrapping of interferometric fringes.

PubMed

Xie, Xianming

2016-08-22

A fresh phase unwrapping algorithm based on iterated unscented Kalman filter is proposed to estimate unambiguous unwrapped phase of interferometric fringes. This method is the result of combining an iterated unscented Kalman filter with a robust phase gradient estimator based on amended matrix pencil model, and an efficient quality-guided strategy based on heap sort. The iterated unscented Kalman filter that is one of the most robust methods under the Bayesian theorem frame in non-linear signal processing so far, is applied to perform simultaneously noise suppression and phase unwrapping of interferometric fringes for the first time, which can simplify the complexity and the difficulty of pre-filtering procedure followed by phase unwrapping procedure, and even can remove the pre-filtering procedure. The robust phase gradient estimator is used to efficiently and accurately obtain phase gradient information from interferometric fringes, which is needed for the iterated unscented Kalman filtering phase unwrapping model. The efficient quality-guided strategy is able to ensure that the proposed method fast unwraps wrapped pixels along the path from the high-quality area to the low-quality area of wrapped phase images, which can greatly improve the efficiency of phase unwrapping. Results obtained from synthetic data and real data show that the proposed method can obtain better solutions with an acceptable time consumption, with respect to some of the most used algorithms.

Do Examinees Understand Score Reports for Alternate Methods of Scoring Computer Based Tests?

ERIC Educational Resources Information Center

Whittaker, Tiffany A.; Williams, Natasha J.; Dodd, Barbara G.

2011-01-01

This study assessed the interpretability of scaled scores based on either number correct (NC) scoring for a paper-and-pencil test or one of two methods of scoring computer-based tests: an item pattern (IP) scoring method and a method based on equated NC scoring. The equated NC scoring method for computer-based tests was proposed as an alternative…

Three-Dimensional Electron Beam Dose Calculations.

NASA Astrophysics Data System (ADS)

Shiu, Almon Sowchee

The MDAH pencil-beam algorithm developed by Hogstrom et al (1981) has been widely used in clinics for electron beam dose calculations for radiotherapy treatment planning. The primary objective of this research was to address several deficiencies of that algorithm and to develop an enhanced version. Two enhancements have been incorporated into the pencil-beam algorithm; one models fluence rather than planar fluence, and the other models the bremsstrahlung dose using measured beam data. Comparisons of the resulting calculated dose distributions with measured dose distributions for several test phantoms have been made. From these results it is concluded (1) that the fluence-based algorithm is more accurate to use for the dose calculation in an inhomogeneous slab phantom, and (2) the fluence-based calculation provides only a limited improvement to the accuracy the calculated dose in the region just downstream of the lateral edge of an inhomogeneity. The source of the latter inaccuracy is believed primarily due to assumptions made in the pencil beam's modeling of the complex phantom or patient geometry. A pencil-beam redefinition model was developed for the calculation of electron beam dose distributions in three dimensions. The primary aim of this redefinition model was to solve the dosimetry problem presented by deep inhomogeneities, which was the major deficiency of the enhanced version of the MDAH pencil-beam algorithm. The pencil-beam redefinition model is based on the theory of electron transport by redefining the pencil beams at each layer of the medium. The unique approach of this model is that all the physical parameters of a given pencil beam are characterized for multiple energy bins. Comparisons of the calculated dose distributions with measured dose distributions for a homogeneous water phantom and for phantoms with deep inhomogeneities have been made. From these results it is concluded that the redefinition algorithm is superior to the conventional, fluence-based, pencil-beam algorithm, especially in predicting the dose distribution downstream of a local inhomogeneity. The accuracy of this algorithm appears sufficient for clinical use, and the algorithm is structured for future expansion of the physical model if required for site specific treatment planning problems.

The Binary Representation of Rational Numbers.

ERIC Educational Resources Information Center

Schmalz, Rosemary

1987-01-01

Presented are the mathematical explanation of the algorithm for representing rational numbers in base two, paper-and-pencil methods for producing the representation, some patterns in these representations, and pseudocode for computer programs to explore these patterns. (MNS)

Assessment of penetrating thermal tissue damage/spread associated with PhotonBlade™, Valleylab™ Pencil, Valleylab™ EDGE™ Coated Pencil, PlasmaBlade® 3.0S and PlasmaBlade® 4.0 for intraoperative tissue dissection using the fresh extirpated porcine muscle model

NASA Astrophysics Data System (ADS)

Bennett, Haydon E.; Taylor, Scott D.; Fugett, James H.; Shrout, Joshua L.; Davison, Paul O.; Ryan, S. Eric; Coad, James E.

2017-02-01

Penetrating thermal tissue damage/spread is an important aspect of many electrosurgical devices and correlates with effective tissue cutting, hemostasis, preservation of adjacent critical structures and tissue healing. This study compared the thermal damage/spread associated with the PhotonBlade, Valleylab Pencil, Valleylab EDGE Coated Pencil, PlasmaBlade 3.0S and PlasmaBlade 4.0, when performing a single pass dynamic tissue cut in fresh extirpated porcine longissimus muscle. These devices were used in a fashion that emulated their use in the clinical setting. Each device's thermal damage/spread, at Minimum, Median and Maximum power input settings, was assessed with nitroblue tetrazolium viability staining in the WVU Pathology Laboratory for Translational Medicine. The thermal damage/spread associated with the PhotonBlade was compared with the other devices tested based on the individual treatment results (n=179 cuts combined). In summary, the PhotonBlade overall demonstrated the least penetrating thermal tissue damage/spread, followed by the PlasmaBlade 4.0, then Valleylab Pencil and PlasmaBlade 3.0S and then Valleylab EDGE Coated Pencil in order of increasing thermal damage/spread depths.

Dietary self-monitoring, but not dietary quality, improves with use of smartphone app technology in an 8-week weight loss trial.

PubMed

Wharton, Christopher M; Johnston, Carol S; Cunningham, Barbara K; Sterner, Danielle

2014-01-01

Dietary self-monitoring is linked to improved weight loss success. Mobile technologies, such as smartphone applications (apps), might allow for improved dietary tracking adherence. The authors assessed the use of a popular smartphone app for dietary self-monitoring and weight loss by comparing it with traditional diet counseling and entry methods. Diet tracking and weight loss were compared across participants during an 8-week weight loss trial. Participants tracked intake using 1 of 3 methods: the mobile app "Lose It!", the memo feature on a smartphone, or a traditional paper-and-pencil method. App users (n = 19) recorded dietary data more consistently compared with the paper-and-pencil group (n = 15; P = .042) but not the memo group (n = 13). All groups lost weight over the course of the study (P = .001), and no difference in weight loss was noted between groups. Smartphone apps could represent a novel and feasible dietary self-monitoring method for individuals. Copyright © 2014 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

Validation of a Paper and Pencil Test Battery for the Diagnosis of Minimal Hepatic Encephalopathy in Korea.

PubMed

Jeong, Jae Yoon; Jun, Dae Won; Bai, Daiseg; Kim, Ji Yean; Sohn, Joo Hyun; Ahn, Sang Bong; Kim, Sang Gyune; Kim, Tae Yeob; Kim, Hyoung Su; Jeong, Soung Won; Cho, Yong Kyun; Song, Do Seon; Kim, Hee Yeon; Jung, Young Kul; Yoon, Eileen L

2017-09-01

The aim of this study was to validate a new paper and pencil test battery to diagnose minimal hepatic encephalopathy (MHE) in Korea. A new paper and pencil test battery was composed of number connection test-A (NCT-A), number connection test-B (NCT-B), digit span test (DST), and symbol digit modality test (SDMT). The norm of the new test was based on 315 healthy individuals between the ages of 20 and 70 years old. Another 63 healthy subjects (n = 31) and cirrhosis patients (n = 32) were included as a validation cohort. All participants completed the new paper and pencil test, a critical flicker frequency (CFF) test and computerized cognitive function test (visual continuous performance test [CPT]). The scores on the NCT-A and NCT-B increased but those of DST and SDMT decreased according to age. Twelve of the cirrhotic patients (37.5%) were diagnosed with MHE based on the new paper and pencil test battery. The total score of the paper and pencil test battery showed good positive correlation with the CFF (r = 0.551, P < 0.001) and computerized cognitive function test. Also, this score was lower in patients with MHE compared to those without MHE (P < 0.001). Scores on the CFF (32.0 vs. 28.7 Hz, P = 0.028) and the computer base cognitive test decreased significantly in patients with MHE compared to those without MHE. Test-retest reliability was comparable. In conclusion, the new paper and pencil test battery including NCT-A, NCT-B, DST, and SDMT showed good correlation with neuropsychological tests. This new paper and pencil test battery could help to discriminate patients with impaired cognitive function in cirrhosis (registered at Clinical Research Information Service [CRIS], https://cris.nih.go.kr/cris, KCT0000955). © 2017 The Korean Academy of Medical Sciences.

Evaluating tablet computers as a survey tool in rural communities.

PubMed

Newell, Steve M; Logan, Henrietta L; Guo, Yi; Marks, John G; Shepperd, James A

2015-01-01

Although tablet computers offer advantages in data collection over traditional paper-and-pencil methods, little research has examined whether the 2 formats yield similar responses, especially with underserved populations. We compared the 2 survey formats and tested whether participants' responses to common health questionnaires or perceptions of usability differed by survey format. We also tested whether we could replicate established paper-and-pencil findings via tablet computer. We recruited a sample of low-income community members living in the rural southern United States. Participants were 170 residents (black = 49%; white = 36%; other races and missing data = 15%) drawn from 2 counties meeting Florida's state statutory definition of rural with 100 persons or fewer per square mile. We randomly assigned participants to complete scales (Center for Epidemiologic Studies Depression Inventory and Regulatory Focus Questionnaire) along with survey format usability ratings via paper-and-pencil or tablet computer. All participants rated a series of previously validated posters using a tablet computer. Finally, participants completed comparisons of the survey formats and reported survey format preferences. Participants preferred using the tablet computer and showed no significant differences between formats in mean responses, scale reliabilities, or in participants' usability ratings. Overall, participants reported similar scales responses and usability ratings between formats. However, participants reported both preferring and enjoying responding via tablet computer more. Collectively, these findings are among the first data to show that tablet computers represent a suitable substitute among an underrepresented rural sample for paper-and-pencil methodology in survey research. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Dosimetric assessment of the PRESAGE dosimeter for a proton pencil beam

NASA Astrophysics Data System (ADS)

Wuu, C.-S.; Xu, Y.; Qian, X.; Adamovics, J.; Cascio, E.; Lu, H.-M.

2013-06-01

The objective of this study is to assess the feasibility of using PRESAGE dosimeters for proton pencil beam dosimetry. Two different formulations of phantom materials were tested for their suitability in characterizing a single proton pencil beam. The dosimetric response of PRESAGE was found to be linear up to 4Gy. First-generation optical CT scanner, OCTOPUSTM was used to implement dose distributions for proton pencil beams since it provides most accurate readout. Percentage depth dose curves and beam profiles for two proton energy, 110 MeV, and 93 MeV, were used to evaluate the dosimetric performance of two PRESAGE phantom formulas. The findings from this study show that the dosimetric properties of the phantom materials match with basic physics of proton beams.

Paper-based potentiometric pH sensor using carbon electrode drawn by pencil

NASA Astrophysics Data System (ADS)

Kawahara, Ryotaro; Sahatiya, Parikshit; Badhulika, Sushmee; Uno, Shigeyasu

2018-04-01

A flexible and disposable paper-based pH sensor fabricated with a pencil-drawn working electrode and a Ag/AgCl paste reference electrode is demonstrated for the first time to show pH response by the potentiometric principle. The sensor substrate is made of chromatography paper with a wax-printed hydrophobic area, and various types of carbon pencils are tested as working electrodes. The pH sensitivities of the electrodes drawn by carbon pencils with different hardnesses range from 16.5 to 26.9 mV/pH. The proposed sensor is expected to be more robust against shape change in electrodes on a flexible substrate than other types of chemiresistive/amperometric pH sensors.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beltran, C; Kamal, H

Purpose: To provide a multicriteria optimization algorithm for intensity modulated radiation therapy using pencil proton beam scanning. Methods: Intensity modulated radiation therapy using pencil proton beam scanning requires efficient optimization algorithms to overcome the uncertainties in the Bragg peaks locations. This work is focused on optimization algorithms that are based on Monte Carlo simulation of the treatment planning and use the weights and the dose volume histogram (DVH) control points to steer toward desired plans. The proton beam treatment planning process based on single objective optimization (representing a weighted sum of multiple objectives) usually leads to time-consuming iterations involving treatmentmore » planning team members. We proved a time efficient multicriteria optimization algorithm that is developed to run on NVIDIA GPU (Graphical Processing Units) cluster. The multicriteria optimization algorithm running time benefits from up-sampling of the CT voxel size of the calculations without loss of fidelity. Results: We will present preliminary results of Multicriteria optimization for intensity modulated proton therapy based on DVH control points. The results will show optimization results of a phantom case and a brain tumor case. Conclusion: The multicriteria optimization of the intensity modulated radiation therapy using pencil proton beam scanning provides a novel tool for treatment planning. Work support by a grant from Varian Inc.« less

Differential pencil beam dose computation model for photons.

PubMed

Mohan, R; Chui, C; Lidofsky, L

1986-01-01

Differential pencil beam (DPB) is defined as the dose distribution relative to the position of the first collision, per unit collision density, for a monoenergetic pencil beam of photons in an infinite homogeneous medium of unit density. We have generated DPB dose distribution tables for a number of photon energies in water using the Monte Carlo method. The three-dimensional (3D) nature of the transport of photons and electrons is automatically incorporated in DPB dose distributions. Dose is computed by evaluating 3D integrals of DPB dose. The DPB dose computation model has been applied to calculate dose distributions for 60Co and accelerator beams. Calculations for the latter are performed using energy spectra generated with the Monte Carlo program. To predict dose distributions near the beam boundaries defined by the collimation system as well as blocks, we utilize the angular distribution of incident photons. Inhomogeneities are taken into account by attenuating the primary photon fluence exponentially utilizing the average total linear attenuation coefficient of intervening tissue, by multiplying photon fluence by the linear attenuation coefficient to yield the number of collisions in the scattering volume, and by scaling the path between the scattering volume element and the computation point by an effective density.

Automated Classification of Medical Percussion Signals for the Diagnosis of Pulmonary Injuries

NASA Astrophysics Data System (ADS)

Bhuiyan, Md Moinuddin

Used for centuries in the clinical practice, audible percussion is a method of eliciting sounds by areas of the human body either by finger tips or by a percussion hammer. Despite its advantages, pulmonary diagnostics by percussion is still highly subjective, depends on the physician's skills, and requires quiet surroundings. Automation of this well-established technique could help amplify its existing merits while removing the above drawbacks. In this study, an attempt is made to automatically decompose clinical percussion signals into a sum of Exponentially Damped Sinusoids (EDS) using Matrix Pencil Method, which in this case form a more natural basis than Fourier harmonics and thus allow for a more robust representation of the signal in the parametric space. It is found that some EDS represent transient oscillation modes of the thorax/abdomen excited by the percussion event, while others are associated with the noise. It is demonstrated that relatively few EDS are usually enough to accurately reconstruct the original signal. It is shown that combining the frequency and damping parameters of these most significant EDS allows for efficient classification of percussion signals into the two main types historically known as "resonant" and "tympanic". This classification ability can provide a basis for the automated objective diagnostics of various pulmonary pathologies including pneumothorax.

Highly sensitive and selective hyphenated technique (molecularly imprinted polymer solid-phase microextraction-molecularly imprinted polymer sensor) for ultra trace analysis of aspartic acid enantiomers.

PubMed

Prasad, Bhim Bali; Srivastava, Amrita; Tiwari, Mahavir Prasad

2013-03-29

The present work is related to combination of molecularly imprinted solid-phase microextraction and complementary molecularly imprinted polymer-sensor. The molecularly imprinted polymer grafted on titanium dioxide modified silica fiber was used for microextraction, while the same polymer immobilized on multiwalled carbon nanotubes/titanium dioxide modified pencil graphite electrode served as a detection tool. In both cases, the surface initiated polymerization was found to be advantageous to obtain a nanometer thin imprinted film. The modified silica fiber exhibited high adsorption capacity and enantioselective diffusion of aspartic acid isomers into respective molecular cavities. This combination enabled double preconcentrations of d- and l-aspartic acid that helped sensing both isomers in real samples, without any cross-selectivity and matrix complications. Taking into account 6×10(4)-fold dilution of serum and 2×10(3)-fold dilution of cerebrospinal fluid required by the proposed method, the limit of detection for l-aspartic acid is 0.031ngmL(-1). Also, taking into account 50-fold dilution required by the proposed method, the limit of detection for d-aspartic acid is 0.031ngmL(-1) in cerebrospinal fluid. Copyright © 2013 Elsevier B.V. All rights reserved.

Effect of pencil grasp on the speed and legibility of handwriting after a 10-minute copy task in Grade 4 children.

PubMed

Schwellnus, Heidi; Carnahan, Heather; Kushki, Azadeh; Polatajko, Helene; Missiuna, Cheryl; Chau, Tom

2012-06-01

To investigate the impact of common pencil grasp patterns on the speed and legibility of handwriting after a 10-minute copy task, intended to induce muscle fatigue, in typically developing children and in those non-proficient in handwriting. A total of 120 Grade 4 students completed a standardised handwriting assessment before and after a 10-minute copy task. The students indicated the perceived difficulty of the handwriting task at baseline and after 10 minutes. The students also completed a self-report questionnaire regarding their handwriting proficiency upon completion. The majority of the students rated higher effort after the 10-minute copy task than at baseline (rank sum: P = 0.00001). The effort ratings were similar for the different grasp patterns (multiple linear regression: F = 0.37, P = 0.895). For both typically developing children and those with handwriting issues, the legibility of the writing samples decreased after the 10-minute copy task but the speed of writing increased. CONCLUSIONS AND SIGNIFICANCE OF THE STUDY: The quality of the handwriting decreased after the 10-minute copy task; however, there was no difference in the quality or speed scores among the different pencil grasps before and after the copy task. The dynamic tripod pencil grasp did not offer any advantage over the lateral tripod or the dynamic or lateral quadrupod pencil grasps in terms of quality of handwriting after a 10-minute copy task. These four pencil grasp patterns performed equivalently. Our findings question the practice of having students adopt the dynamic tripod pencil grasp. © 2012 The Authors Australian Occupational Therapy Journal © 2012 Occupational Therapy Australia.

A comparison of paper-and-pencil and computerized forms of Line Orientation and Enhanced Cued Recall Tests.

PubMed

Aşkar, Petek; Altun, Arif; Cangöz, Banu; Cevik, Vildan; Kaya, Galip; Türksoy, Hasan

2012-04-01

The purpose of this study was to assess whether a computerized battery of neuropsychological tests could produce similar results as the conventional forms. Comparisons on 77 volunteer undergraduates were carried out with two neuropsychological tests: Line Orientation Test and Enhanced Cued Recall Test. Firstly, students were assigned randomly across the test medium (paper-and-pencil versus computerized). Secondly, the groups were given the same test in the other medium after a 30-day interval between tests. Results showed that the Enhanced Cued Recall Test-Computer-based did not correlate with the Enhanced Cued Recall Test-Paper-and-pencil results. Line Orientation Test-Computer-based scores, on the other hand, did correlate significantly with the Line Orientation Test-Paper-and-pencil version. In both tests, scores were higher on paper-and-pencil tests compared to computer-based tests. Total score difference between modalities was statistically significant for both Enhanced Cued Recall Tests and for the Line Orientation Test. In both computer-based tests, it took less time for participants to complete the tests.

Should We Trust Web-Based Studies? A Comparative Analysis of Six Preconceptions about Internet Questionnaires

ERIC Educational Resources Information Center

Gosling, Samuel D.; Vazire, Simine; Srivastava, Sanjay; Oliver, John

2004-01-01

The rapid growth of the Internet provides a wealth of new research opportunities for psychologists. Internet data collection methods, with a focus on self-report questionnaires from self-selected samples, are evaluated and compared with traditional paper-and-pencil methods. Six preconceptions about Internet samples and data quality are evaluated…

Optimum target sizes for a sequential sawing process

Treesearch

H. Dean Claxton

1972-01-01

A method for solving a class of problems in random sequential processes is presented. Sawing cedar pencil blocks is used to illustrate the method. Equations are developed for the function representing loss from improper sizing of blocks. A weighted over-all distribution for sawing and drying operations is developed and graphed. Loss minimizing changes in the control...

Getting Real: Implementing Assessment Alternatives in Mathematics.

ERIC Educational Resources Information Center

Hopkins, Martha H.

1997-01-01

Recounts experiences of a university professor who returned to the elementary classroom and attempted to implement the National Council of Teachers of Mathematics Standards and appropriate assessment methods, including nontraditional paper-and-pencil tasks, journal-like writing assignments, focused observations, and performance-based assessments…

SU-E-T-252: Developing a Pencil Beam Dose Calculation Algorithm for CyberKnife System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang, B; Duke University Medical Center, Durham, NC; Liu, B

2015-06-15

Purpose: Currently there are two dose calculation algorithms available in the Cyberknife planning system: ray-tracing and Monte Carlo, which is either not accurate or time-consuming for irregular field shaped by the MLC that was recently introduced. The purpose of this study is to develop a fast and accurate pencil beam dose calculation algorithm which can handle irregular field. Methods: A pencil beam dose calculation algorithm widely used in Linac system is modified. The algorithm models both primary (short range) and scatter (long range) components with a single input parameter: TPR{sub 20}/{sub 10}. The TPR{sub 20}/{sub 20}/{sub 10} value was firstmore » estimated to derive an initial set of pencil beam model parameters (PBMP). The agreement between predicted and measured TPRs for all cones were evaluated using the root mean square of the difference (RMSTPR), which was then minimized by adjusting PBMPs. PBMPs are further tuned to minimize OCR RMS (RMSocr) by focusing at the outfield region. Finally, an arbitrary intensity profile is optimized by minimizing RMSocr difference at infield region. To test model validity, the PBMPs were obtained by fitting to only a subset of cones (4) and applied to all cones (12) for evaluation. Results: With RMS values normalized to the dmax and all cones combined, the average RMSTPR at build-up and descending region is 2.3% and 0.4%, respectively. The RMSocr at infield, penumbra and outfield region is 1.5%, 7.8% and 0.6%, respectively. Average DTA in penumbra region is 0.5mm. There is no trend found in TPR or OCR agreement among cones or depths. Conclusion: We have developed a pencil beam algorithm for Cyberknife system. The prediction agrees well with commissioning data. Only a subset of measurements is needed to derive the model. Further improvements are needed for TPR buildup region and OCR penumbra. Experimental validations on MLC shaped irregular field needs to be performed. This work was partially supported by the National Natural Science Foundation of China (61171005) and the China Scholarship Council (CSC)« less

Differential expression of matrix metalloproteinase-13 in mucinous and nonmucinous colorectal carcinomas.

PubMed

Foda, Abd Al-Rahman Mohammad; El-Hawary, Amira K; Abdel-Aziz, Azza

2013-08-01

Colorectal carcinoma (CRC) is a major health problem all over the world. Mucinous CRCs are known to have a peculiar behavior and genetic derangements. This study aimed to investigate matrix metalloproteinase (MMP)-13 expression in mucinous and nonmucinous CRCs. We studied tumor tissue specimens from 150 patients with mucinous and nonmucinous CRC who underwent radical surgery from January 2007 to January 2012. High-density manual tissue microarrays were constructed using a modified mechanical pencil tip technique, and paraffin sections were submitted for immunohistochemistry using MMP-13. Statistical analysis was performed for clinical and pathological data of all studied cases together with MMP-13 expression in mucinous and nonmucinous groups. Mucinous carcinoma was significantly associated with young age, more depth of invasion, lymph node metastasis, and less peritumoral and intratumoral neutrophils. Nonmucinous carcinomas showed higher MMP-13 expression compared with mucinous carcinomas. Despite the negative or low expression of MMP-13, mucinous carcinomas had more depth of invasion and more frequency of lymph node metastasis than did nonmucinous carcinomas. Copyright © 2013 Elsevier Inc. All rights reserved.

String and Sticky Tape Experiments: Refractive Index of Liquids.

ERIC Educational Resources Information Center

Edge, R. D., Ed.

1979-01-01

Describes a simple method of measuring the refractive index of a liquid using a paper cup, a liquid, a pencil, and a ruler. Uses the ratio between the actual depth and the apparent depth of the cup to calculate the refractive index. (GA)

Technical Note: A direct ray-tracing method to compute integral depth dose in pencil beam proton radiography with a multilayer ionization chamber.

PubMed

Farace, Paolo; Righetto, Roberto; Deffet, Sylvain; Meijers, Arturs; Vander Stappen, Francois

2016-12-01

To introduce a fast ray-tracing algorithm in pencil proton radiography (PR) with a multilayer ionization chamber (MLIC) for in vivo range error mapping. Pencil beam PR was obtained by delivering spots uniformly positioned in a square (45 × 45 mm 2 field-of-view) of 9 × 9 spots capable of crossing the phantoms (210 MeV). The exit beam was collected by a MLIC to sample the integral depth dose (IDD MLIC ). PRs of an electron-density and of a head phantom were acquired by moving the couch to obtain multiple 45 × 45 mm 2 frames. To map the corresponding range errors, the two-dimensional set of IDD MLIC was compared with (i) the integral depth dose computed by the treatment planning system (TPS) by both analytic (IDD TPS ) and Monte Carlo (IDD MC ) algorithms in a volume of water simulating the MLIC at the CT, and (ii) the integral depth dose directly computed by a simple ray-tracing algorithm (IDD direct ) through the same CT data. The exact spatial position of the spot pattern was numerically adjusted testing different in-plane positions and selecting the one that minimized the range differences between IDD direct and IDD MLIC . Range error mapping was feasible by both the TPS and the ray-tracing methods, but very sensitive to even small misalignments. In homogeneous regions, the range errors computed by the direct ray-tracing algorithm matched the results obtained by both the analytic and the Monte Carlo algorithms. In both phantoms, lateral heterogeneities were better modeled by the ray-tracing and the Monte Carlo algorithms than by the analytic TPS computation. Accordingly, when the pencil beam crossed lateral heterogeneities, the range errors mapped by the direct algorithm matched better the Monte Carlo maps than those obtained by the analytic algorithm. Finally, the simplicity of the ray-tracing algorithm allowed to implement a prototype procedure for automated spatial alignment. The ray-tracing algorithm can reliably replace the TPS method in MLIC PR for in vivo range verification and it can be a key component to develop software tools for spatial alignment and correction of CT calibration.

11. Photographic copy of architect's rendering, from the pencil tracings ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

11. Photographic copy of architect's rendering, from the pencil tracings in the possession of Potter, Lawson and Pawlowsky, WISCONSIN AVENUE ELEVATION - Manchester's Department Store Building, 2 East Mifflin Street, Madison, Dane County, WI

10. Photographic copy of architect's rendering, from the pencil tracings ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. Photographic copy of architect's rendering, from the pencil tracings in the possession of Potter, Lawson and Pawlowsky, MIFFLIN STREET ELEVATION - Manchester's Department Store Building, 2 East Mifflin Street, Madison, Dane County, WI

12. Photographic copy of architect's rendering, from the pencil tracings ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. Photographic copy of architect's rendering, from the pencil tracings in the possession of Potter, Lawson and Pawlowsky, TYPICAL FLOOR PLAN - Manchester's Department Store Building, 2 East Mifflin Street, Madison, Dane County, WI

How to Simply Demonstrate Diamagnetic Levitation with Pencil Lead

ERIC Educational Resources Information Center

Koudelkova, Vera

2016-01-01

A new simple arrangement how to demonstrate diamagnetic levitation is presented. It uses pencil lead levitating in a track built from neodymium magnets. This arrangement can also be used as a classroom experiment.

The Relationship Between Computer Experience and Computerized Cognitive Test Performance Among Older Adults

PubMed Central

2013-01-01

Objective. This study compared the relationship between computer experience and performance on computerized cognitive tests and a traditional paper-and-pencil cognitive test in a sample of older adults (N = 634). Method. Participants completed computer experience and computer attitudes questionnaires, three computerized cognitive tests (Useful Field of View (UFOV) Test, Road Sign Test, and Stroop task) and a paper-and-pencil cognitive measure (Trail Making Test). Multivariate analysis of covariance was used to examine differences in cognitive performance across the four measures between those with and without computer experience after adjusting for confounding variables. Results. Although computer experience had a significant main effect across all cognitive measures, the effect sizes were similar. After controlling for computer attitudes, the relationship between computer experience and UFOV was fully attenuated. Discussion. Findings suggest that computer experience is not uniquely related to performance on computerized cognitive measures compared with paper-and-pencil measures. Because the relationship between computer experience and UFOV was fully attenuated by computer attitudes, this may imply that motivational factors are more influential to UFOV performance than computer experience. Our findings support the hypothesis that computer use is related to cognitive performance, and this relationship is not stronger for computerized cognitive measures. Implications and directions for future research are provided. PMID:22929395

SU-F-J-201: Validation Study of Proton Radiography Against CT Data for Quantitative Imaging of Anatomical Changes in Head and Neck Patients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hammi, A; Weber, D; Lomax, A

2016-06-15

Purpose: In clinical pencil-beam-scanned (PBS) proton therapy, the advantage of the characteristic sharp dose fall-off after the Bragg Peak (BP) becomes a disadvantage if the BP positions of a plan’s constituent pencil beams are shifted, eg.due to anatomical changes. Thus, for fractionated PBS proton therapy, accurate knowledge of the water equivalent path length (WEPL) of the traversed anatomy is critical. In this work we investigate the feasibility of using 2D proton range maps (proton radiography, PR) with the active-scanning gantry at PSI. Methods: We simulated our approach using Monte Carlo methods (MC) to simulate proton beam interactions in patients usingmore » clinical imaging data. We selected six head and neck cases having significant anatomical changes detected in per-treatment CTs.PRs (two at 0°/90°) were generated from MC simulations of low-dose pencil beams at 230MeV. Each beam’s residual depth-dose was propagated through the patient geometry (from CT) and detected on exiting the patient anatomy in an ideal depth-resolved detector (eg. range telescope). Firstly, to validate the technique, proton radiographs were compared to the ground truth, which was the WEPL from ray-tracing in the patient CT at the pencil beam location. Secondly, WEPL difference maps (per-treatment – planning imaging timepoints) were then generated to locate the anatomical changes, both in the CT (ground truth) and in the PRs. Binomial classification was performed to evaluate the efficacy of the technique relative to CT. Results: Over the projections simulated over all six patients, 70%, 79% and 95% of the grid points agreed with the ground truth proton range to within ±0.5%, ±1%, and ±3% respectively. The sensitivity, specificity, precision and accuracy were high (mean±1σ, 83±8%, 87±13%, 95±10%, 83±7% respectively). Conclusion: We show that proton-based radiographic images can accurately monitor patient positioning and in vivo range verification, while providing equivalent WEPL information to a CT scan, with the advantage of a much lower imaging dose.« less

Self-Referencing Hartmann Test for Large-Aperture Telescopes

NASA Technical Reports Server (NTRS)

Korechoff, Robert P.; Oseas, Jeffrey M.

2010-01-01

A method is proposed for end-to-end, full aperture testing of large-aperture telescopes using an innovative variation of a Hartmann mask. This technique is practical for telescopes with primary mirrors tens of meters in diameter and of any design. Furthermore, it is applicable to the entire optical band (near IR, visible, ultraviolet), relatively insensitive to environmental perturbations, and is suitable for ambient laboratory as well as thermal-vacuum environments. The only restriction is that the telescope optical axis must be parallel to the local gravity vector during testing. The standard Hartmann test utilizes an array of pencil beams that are cut out of a well-corrected wavefront using a mask. The pencil beam array is expanded to fill the full aperture of the telescope. The detector plane of the telescope is translated back and forth along the optical axis in the vicinity of the nominal focal plane, and the centroid of each pencil beam image is recorded. Standard analytical techniques are then used to reconstruct the telescope wavefront from the centroid data. The expansion of the array of pencil beams is usually accomplished by double passing the beams through the telescope under test. However, this requires a well-corrected, autocollimation flat, the diameter or which is approximately equal to that of the telescope aperture. Thus, the standard Hartmann method does not scale well because of the difficulty and expense of building and mounting a well-corrected, large aperture flat. The innovation in the testing method proposed here is to replace the large aperture, well-corrected, monolithic autocollimation flat with an array of small-aperture mirrors. In addition to eliminating the need for a large optic, the surface figure requirement for the small mirrors is relaxed compared to that required of the large autocollimation flat. The key point that allows this method to work is that the small mirrors need to operate as a monolithic flat only with regard to tip/tilt and not piston because in collimated space piston has no effect on the image centroids. The problem of aligning the small mirrors in tip/tilt requires a two-part solution. First, each mirror is suspended from a two-axis gimbal. The orientation of the gimbal is maintained by gravity. Second, the mirror is aligned such that the mirror normal is parallel to gravity vector. This is accomplished interferometrically in a test fixture. Of course, the test fixture itself needs to be calibrated with respect to gravity.

"Sack Time" pencil drawing on north wall of sack room, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

"Sack Time" pencil drawing on north wall of sack room, northeast corner, facing north. - Camp Tulelake, Shop-Storage Building, West Side of Hill Road, 2 miles South of State Highway 161, Tulelake, Siskiyou County, CA

9. Photographic copy of architect's rendering, from the pencil tracings ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. Photographic copy of architect's rendering, from the pencil tracings in the possession of Potter, Lawson and Pawlowsky, ELEVATIONS AND TWO SECTIONS - Manchester's Department Store Building, 2 East Mifflin Street, Madison, Dane County, WI

Reference dosimetry of proton pencil beams based on dose-area product: a proof of concept.

PubMed

Gomà, Carles; Safai, Sairos; Vörös, Sándor

2017-06-21

This paper describes a novel approach to the reference dosimetry of proton pencil beams based on dose-area product ([Formula: see text]). It depicts the calibration of a large-diameter plane-parallel ionization chamber in terms of dose-area product in a 60 Co beam, the Monte Carlo calculation of beam quality correction factors-in terms of dose-area product-in proton beams, the Monte Carlo calculation of nuclear halo correction factors, and the experimental determination of [Formula: see text] of a single proton pencil beam. This new approach to reference dosimetry proves to be feasible, as it yields [Formula: see text] values in agreement with the standard and well-established approach of determining the absorbed dose to water at the centre of a broad homogeneous field generated by the superposition of regularly-spaced proton pencil beams.

Effect of pencil grasp on the speed and legibility of handwriting in children.

PubMed

Schwellnus, Heidi; Carnahan, Heather; Kushki, Azadeh; Polatajko, Helene; Missiuna, Cheryl; Chau, Tom

2012-01-01

Pencil grasps other than the dynamic tripod may be functional for handwriting. This study examined the impact of grasp on handwriting speed and legibility. We videotaped 120 typically developing fourth-grade students while they performed a writing task. We categorized the grasps they used and evaluated their writing for speed and legibility using a handwriting assessment. Using linear regression analysis, we examined the relationship between grasp and handwriting. We documented six categories of pencil grasp: four mature grasp patterns, one immature grasp pattern, and one alternating grasp pattern. Multiple linear regression results revealed no significant effect for mature grasp on either legibility or speed. Pencil grasp patterns did not influence handwriting speed or legibility in this sample of typically developing children. This finding adds to the mounting body of evidence that alternative grasps may be acceptable for fast and legible handwriting. Copyright © 2012 by the American Occupational Therapy Association, Inc.

Evaluating the generalization of math fact fluency gains across paper and computer performance modalities.

PubMed

Duhon, Gary J; House, Sara H; Stinnett, Terry A

2012-06-01

Computer-based interventions are being used more in the classroom. Student responses to these interventions often contribute to decisions making regarding important outcomes. It is important to understand the effect of these interventions within the context of the intervention as well as across related context. The current study examined the generalization of math fact fluency gains resulting from a computer-based intervention to paper-and-pencil performance. A total of 31 second grade students completed fluency drills on the computer or with paper and pencil. Pretest-posttest performance on both computer and paper and pencil for all students was evaluated using a doubly multivariate repeated measure ANOVA. Results indicated that gains achieved on the computer did not generalize to paper-and-pencil performance. Copyright © 2012 Society for the Study of School Psychology. Published by Elsevier Ltd. All rights reserved.

Estimation of the peak entrance surface air kerma for patients undergoing computed tomography-guided procedures.

PubMed

Avilés Lucas, P; Dance, D R; Castellano, I A; Vañó, E

2005-01-01

The purpose of this work was to develop a method for estimating the patient peak entrance surface air kerma from measurements using a pencil ionisation chamber on dosimetry phantoms exposed in a computed tomography (CT) scanner. The method described is especially relevant for CT fluoroscopy and CT perfusion procedures where the peak entrance surface air kerma is the risk-related quantity of primary concern. Pencil ionisation chamber measurements include scattered radiation, which is outside the primary radiation field, and that must be subtracted in order to derive the peak entrance surface air kerma. A Monte Carlo computer model has therefore been used to calculate correction factors, which may be applied to measurements of the CT dose index obtained using a pencil ionisation chamber in order to estimate the peak entrance surface air kerma. The calculations were made for beam widths of 5, 7, 10 and 20 mm, for seven positions of the phantom, and for the geometry of a GE HiSpeed CT/i scanner. The program was validated by comparing measurements and calculations of CTDI for various vertical positions of the phantom and by directly estimating the peak ESAK using the program. Both validations showed agreement within statistical uncertainties (standard deviation of 2.3% or less). For the GE machine, the correction factors vary by approximately 10% with slice width for a fixed phantom position, being largest for the 20 mm beam width, and at that beam width range from 0.87 when the phantom surface is at the isocentre to 1.23 when it is displaced vertically by 24 cm.

A systematic linear space approach to solving partially described inverse eigenvalue problems

NASA Astrophysics Data System (ADS)

Hu, Sau-Lon James; Li, Haujun

2008-06-01

Most applications of the inverse eigenvalue problem (IEP), which concerns the reconstruction of a matrix from prescribed spectral data, are associated with special classes of structured matrices. Solving the IEP requires one to satisfy both the spectral constraint and the structural constraint. If the spectral constraint consists of only one or few prescribed eigenpairs, this kind of inverse problem has been referred to as the partially described inverse eigenvalue problem (PDIEP). This paper develops an efficient, general and systematic approach to solve the PDIEP. Basically, the approach, applicable to various structured matrices, converts the PDIEP into an ordinary inverse problem that is formulated as a set of simultaneous linear equations. While solving simultaneous linear equations for model parameters, the singular value decomposition method is applied. Because of the conversion to an ordinary inverse problem, other constraints associated with the model parameters can be easily incorporated into the solution procedure. The detailed derivation and numerical examples to implement the newly developed approach to symmetric Toeplitz and quadratic pencil (including mass, damping and stiffness matrices of a linear dynamic system) PDIEPs are presented. Excellent numerical results for both kinds of problem are achieved under the situations that have either unique or infinitely many solutions.

An Application of the Rasch Model to Computerized Adaptive Testing.

ERIC Educational Resources Information Center

Wisniewski, Dennis R.

Three questions concerning the Binary Search Method (BSM) of computerized adaptive testing were studied: (1) whether it provided a reliable and valid estimation of examinee ability; (2) its effect on examinee attitudes toward computerized adaptive testing and conventional paper-and-pencil testing; and (3) the relationship between item response…

Constructive Student Feedback: Online vs. Traditional Course Evaluations

ERIC Educational Resources Information Center

Donovan, Judy; Mader, Cynthia E.; Shinsky, John

2010-01-01

Substantial efforts have been made recently to compare the effectiveness of traditional course formats to alternative formats (most often, online delivery compared to traditional on-site delivery). This study examines, not the delivery format but rather the evaluation format. It compares traditional paper and pencil methods for course evaluation…

Comparing Data Collected by Computerized and Written Surveys for Adolescence Health Research

ERIC Educational Resources Information Center

Wu, Ying; Newfield, Susan A.

2007-01-01

Background: This study assessed whether data-collection formats, computerized versus paper-and-pencil, affect response patterns and descriptive statistics for adolescent health assessment surveys. Youth were assessed as part of a health risk reduction program. Methods: Baseline data from 1131 youth were analyzed. Participants completed the…

Differential Relationships between Religiosity, Cigarette Smoking, and Waterpipe Use: Implications for College Student Health

ERIC Educational Resources Information Center

Klassen, Brian J.; Smith, Kathryn Z.; Grekin, Emily R.

2013-01-01

Objective: Using a framework informed by problem behavior theory, the authors examined differential relationships between religiosity and the frequency of cigarette and waterpipe tobacco smoking. Participants: Six hundred fourteen individuals beginning their freshman year at a large, public, midwestern university. Methods: Paper-and-pencil surveys…

The Words in My Pencil: Considering Children's Writing.

ERIC Educational Resources Information Center

Martin, Anne

Methods of eliciting writing from children are explored in this monograph, which includes samples of nine- and ten-year-old students' writing. The monograph offers four recommendations for improving writing skills: make writing a daily activity; take children's writing seriously; maintain flexible standards of form and language; and identify group…

Implicit Attitudes toward Violence among Male Perpetrators of Intimate Partner Violence: A Preliminary Investigation

ERIC Educational Resources Information Center

Eckhardt, Christopher I.; Samper, Rita; Suhr, Laura; Holtzworth-Munroe, Amy

2012-01-01

Whereas cognitive variables are hypothesized to play an important role in intimate partner violence (IPV) etiology and intervention, cognitive assessment methods have largely targeted offenders' explicit, controlled cognitive processing using paper-and-pencil questionnaires prone to social desirability biases. Using an implicit measure of…

SU-E-T-207: Comparison of Integrated Tissue Air Ratio (ITAR) to Traditional TAR for Kilovoltage Pencil-Beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanlon, J; Koruga, I; Chell, E

2015-06-15

Purpose: Clinically viable depth dose determination in kilovoltage pencil-beams is a great challenge that resulted in a published dosimetry method called ITAR, which involves measurement of air kerma and attenuation with a detector in a low scatter environment coupled with MCNP scatter calculations. The objective of this work is to compare ITAR to traditional TAR using inherently water-proof microchambers that have only recently become commercially available. Methods: An Exradin A26 microchamber was centered 150 mm from a 100 kVp x-ray source with 2 mm aluminum HVL. Depth dose in water from 16 to 24 mm in 2 mm increments wasmore » determined by: (1) placing blocks of Plastic Water LR near the source to minimize scatter and using previously published conversion coefficients [ITAR method] and (2) submerging the detector in a water tank with 2 mm thick Plastic Water LR walls and jogging the tank with motor controllers while keeping the detector position fixed [traditional TAR method]. Each method was repeated four to five times. For each repetition, dose was measured free in-air to normalize the data for exponential regression. Results: Traditional TAR indicated higher depth dose than ITAR; differences ranged from 2.1% at 24 mm depth to 2.5% at 16 mm depth. However, the results of traditional TAR did not include a correction for Pq,cham because it is unknown for this detector type in these conditions. It is estimated that the component of Pq,cham due to the effect of water displacement alone is ∼0.94, but Pq,cham is likely several percent larger than 0.94 due to the energy dependency of the microchamber in the presence of low energy scatter that is not present during in-air calibration. Conclusion: The ITAR method remains preferable for clinical depth dose determination in kilovoltage pencil-beams due to Pq,cham being unknown for suitable detectors in relevant conditions. All four of the authors are either current full time employees, which include stock option grants, or consultants of Oraya Therapeutics Inc.« less

6. Photocopy of pencil drawing (on file at La Grande ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. Photocopy of pencil drawing (on file at La Grande District Office, La Grande, Oregon) USDA Forest Service, 1939 CIRCULATION PLAN - Union Ranger District Compound, Fronting State Highway 203, at West edge of Union, Union, Union County, OR

Complications after LP related to needle type: pencil-point versus Quincke.

PubMed

Aamodt, A; Vedeler, C

2001-06-01

We studied the incidence of complications after diagnostic lumbar puncture (LP) related to needle type. A 5 months' observational study of routine diagnostic LP in 83 patients was conducted. Significantly more headache was observed after LP using thicker cutting needles (20G Quincke) compared with thinner cutting or non-cutting needles (22G Quincke or pencil-point). No significant difference in complications after LP was found between the 22G Quincke and pencil-point needles. The size of the needle and not the needle shape seems to be the main determinant for post-dural puncture headache (PDPH).

Non-gaussian statistics of pencil beam surveys

NASA Technical Reports Server (NTRS)

Amendola, Luca

1994-01-01

We study the effect of the non-Gaussian clustering of galaxies on the statistics of pencil beam surveys. We derive the probability from the power spectrum peaks by means of Edgeworth expansion and find that the higher order moments of the galaxy distribution play a dominant role. The probability of obtaining the 128 Mpc/h periodicity found in pencil beam surveys is raised by more than one order of magnitude, up to 1%. Further data are needed to decide if non-Gaussian distribution alone is sufficient to explain the 128 Mpc/h periodicity, or if extra large-scale power is necessary.

The measurement of enhancement in mathematical abilities as a result of joint cognitive trainings in numerical and visual- spatial skills: A preliminary study

NASA Astrophysics Data System (ADS)

Agus, M.; Mascia, M. L.; Fastame, M. C.; Melis, V.; Pilloni, M. C.; Penna, M. P.

2015-02-01

A body of literature shows the significant role of visual-spatial skills played in the improvement of mathematical skills in the primary school. The main goal of the current study was to investigate the impact of a combined visuo-spatial and mathematical training on the improvement of mathematical skills in 146 second graders of several schools located in Italy. Participants were presented single pencil-and-paper visuo-spatial or mathematical trainings, computerised version of the above mentioned treatments, as well as a combined version of computer-assisted and pencil-and-paper visuo-spatial and mathematical trainings, respectively. Experimental groups were presented with training for 3 months, once a week. All children were treated collectively both in computer-assisted or pencil-and-paper modalities. At pre and post-test all our participants were presented with a battery of objective tests assessing numerical and visuo-spatial abilities. Our results suggest the positive effect of different types of training for the empowerment of visuo-spatial and numerical abilities. Specifically, the combination of computerised and pencil-and-paper versions of visuo-spatial and mathematical trainings are more effective than the single execution of the software or of the pencil-and-paper treatment.

Pencil graphite leads as simple amperometric sensors for microchip electrophoresis.

PubMed

Natiele Tiago da Silva, Eiva; Marques Petroni, Jacqueline; Gabriel Lucca, Bruno; Souza Ferreira, Valdir

2017-11-01

In this work we demonstrate, for the first time, the use of inexpensive commercial pencil graphite leads as simple amperometric sensors for microchip electrophoresis. A PDMS support containing one channel was fabricated through soft lithography and sanded pencil graphite leads were inserted into this channel to be used as working electrodes. The electrochemical and morphological characterization of the sensor was carried out. The graphite electrode was coupled to PDMS microchips in end-channel configuration and electrophoretic experiments were performed using nitrite and ascorbate as probe analytes. The analytes were successfully separated and detected in well-defined peaks with satisfactory resolution using the microfluidic platform proposed. The repeatability of the pencil graphite electrode was satisfactory (RSD values of 1.6% for nitrite and 12.3% for ascorbate, regarding the peak currents) and its lifetime was estimated to be ca. 700 electrophoretic runs over a cost of ca. $ 0.05 per electrode. The limits of detection achieved with this system were 2.8 μM for nitrite and 5.7 μM for ascorbate. For proof of principle, the pencil graphite electrode was employed for the real analysis of well water samples and nitrite was successfully quantified at levels below its maximum contaminant level established in Brazil and US. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Curls of My Dreams.

ERIC Educational Resources Information Center

Greenman, Geri

2001-01-01

Describes an art activity in which students draw ribbons (thin watercolor paper that, when torn, will stand up in a curling fashion). Explains in detail the assignment in which students used pencil rendering or charcoal pencil depending on the type of paper used for the assignment. (CMK)

Dose calculation algorithm of fast fine-heterogeneity correction for heavy charged particle radiotherapy.

PubMed

Kanematsu, Nobuyuki

2011-04-01

This work addresses computing techniques for dose calculations in treatment planning with proton and ion beams, based on an efficient kernel-convolution method referred to as grid-dose spreading (GDS) and accurate heterogeneity-correction method referred to as Gaussian beam splitting. The original GDS algorithm suffered from distortion of dose distribution for beams tilted with respect to the dose-grid axes. Use of intermediate grids normal to the beam field has solved the beam-tilting distortion. Interplay of arrangement between beams and grids was found as another intrinsic source of artifact. Inclusion of rectangular-kernel convolution in beam transport, to share the beam contribution among the nearest grids in a regulatory manner, has solved the interplay problem. This algorithmic framework was applied to a tilted proton pencil beam and a broad carbon-ion beam. In these cases, while the elementary pencil beams individually split into several tens, the calculation time increased only by several times with the GDS algorithm. The GDS and beam-splitting methods will complementarily enable accurate and efficient dose calculations for radiotherapy with protons and ions. Copyright © 2010 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Synthesis and characterization of a material derived from 4-mercaptobenzoic acid: A novel platform for oligonucleotide immobilization.

PubMed

Alves, Rafael da Fonseca; da Silva, Amanda Gonçalves; Ferreira, Lucas Franco; Franco, Diego Leoni

2017-04-01

This paper reports the electrochemical modification of pencil carbon graphite electrodes with a polymeric material derived from 4-mercaptobenzoic acid. Acidic solutions (pH 0 and 5.02) yielded an insulating polymeric film with anionic permselective properties. Scanning Electron Microscopy (SEM) analysis showed a complete coverage of the carbon graphite electrodes with a laminar-like polymeric structure. Different characterization studies indicate that the carboxyl group remained unchanged since the absorbance peak and oxidation potential did not change with the increase in pH at the pK a accounting for the carboxyl/carboxylate redox transition. The functionalized matrix was activated using carbodiimide, succinimide and an amine-modified oligonucleotide. The immobilization and hybridization processes were successfully verified using the redox electroactive indicator methylene blue, where better electrochemical signals were obtained when compared with the traditional self-assembled monolayer system. The selectivity of the system was verified using a noncomplementary target where no significant difference in electric current was observed when compared to the system containing only the probe. The method showed a good linear correlation coefficient (r 2 =0.9915), low limit of detection (1.17nmolL -1 ), and an acceptable precision (RSD=2.75%). The proposed method is suitable for further studies using different sequences of oligonucleotides. Copyright © 2016 Elsevier B.V. All rights reserved.

75 FR 54089 - Certain Cased Pencils From the People's Republic of China: Extension of Time Limit for...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-03

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-827] Certain Cased Pencils From... Duty Administrative Review AGENCY: Import Administration, International Trade Administration... (202) 482-0914; AD/CVD Operations, Office 1, Import Administration, International Trade Administration...

Differences in paper-and-pencil versus computerized line bisection according to ADHD subtype and hand-use.

PubMed

Rolfe, Mei Hsin Suzanne; Hamm, Jeff P; Waldie, Karen E

2008-03-01

Two versions of the line bisection task, paper-and-pencil and computerized, were administered to non-medicated children (5-12 years) with and without Attention-Deficit/Hyperactivity Disorder (ADHD). Fifteen children were classified with ADHD-Inattentive type (ADHD-I), 15 were classified with ADHD-Combined or Hyperactive-Impulsive type (ADHD-C), and 15 children served as controls. During the paper-and-pencil task, and irrespective of hand-use, participants with ADHD-C bisected lines with a right bias, whereas participants with ADHD-I showed a leftwards bias. Interestingly, during the computerized version, an opposite pattern of hemineglect was observed with a leftwards bias for participants with ADHD-C and a rightwards bias for participants with ADHD-I. These findings suggest that different task demands are associated with the paper-and-pencil and computerized tasks. The findings also suggest that the two subtypes differ according to their cognitive profile, and possibly differ as to their underlying neural impairment.

Pencil beam characteristics of the next-generation proton scanning gantry of PSI: design issues and initial commissioning results

NASA Astrophysics Data System (ADS)

Pedroni, E.; Meer, D.; Bula, C.; Safai, S.; Zenklusen, S.

2011-07-01

In this paper we report on the main design features, on the realization process and on selected first results of the initial commissioning of the new Gantry 2 of PSI for the delivery of proton therapy with new advanced pencil beam scanning techniques. We present briefly the characteristics of the new gantry system with main emphasis on the beam optics, on the characterization of the pencil beam used for scanning and on the performance of the scanning system. The idea is to give an overview of the major components of the whole system. The main long-term technical goal of the new equipment of Gantry 2 is to expand the use of pencil beam scanning to the whole spectrum of clinical indications including moving targets. We report here on the initial experience and problems encountered in the development of the system with selected preliminary results of the ongoing commissioning of Gantry 2.

Weight concerns scale applied to college students: comparison between pencil-and-paper and online formats.

PubMed

Dias, Juliana Chioda Ribeiro; Maroco, João; Campos, Juliana Alvares Duarte Bonini

2015-03-01

Online data collection is becoming increasingly common and has some advantages compared to traditional paper-and-pencil formats, such as reducing loss of data, increasing participants' privacy, and decreasing the effect of social desirability. However, the validity and reliability of this administration format must be established before results can be considered acceptable. The aim of this study was to evaluate the validity, reliability, and equivalence of paper-and-pencil and online versions of the Weight Concerns Scale (WCS) when applied to Brazilian university students. A crossover design was used, and the Portuguese version of the WCS (in both paper-and-pencil and online formats) was completed by 100 college students. The results indicated adequate fit in both formats. The simultaneous fit of data for both groups was excellent, with strong invariance between models. Adequate convergent validity, internal consistency, and mean score equivalence of the WCS in both formats were observed. Thus, the WCS presented adequate reliability and validity in both administration formats, with equivalence/stability between answers.

Modeling of beam customization devices in the pencil-beam splitting algorithm for heavy charged particle radiotherapy.

PubMed

Kanematsu, Nobuyuki

2011-03-07

A broad-beam-delivery system for radiotherapy with protons or ions often employs multiple collimators and a range-compensating filter, which offer complex and potentially useful beam customization. It is however difficult for conventional pencil-beam algorithms to deal with fine structures of these devices due to beam-size growth during transport. This study aims to avoid the difficulty with a novel computational model. The pencil beams are initially defined at the range-compensating filter with angular-acceptance correction for upstream collimation followed by stopping and scattering. They are individually transported with possible splitting near the aperture edge of a downstream collimator to form a sharp field edge. The dose distribution for a carbon-ion beam was calculated and compared with existing experimental data. The penumbra sizes of various collimator edges agreed between them to a submillimeter level. This beam-customization model will be used in the greater framework of the pencil-beam splitting algorithm for accurate and efficient patient dose calculation.

Computerized Testing of Level III Associate Degree Nursing Students versus Paper and Pencil Testing Methods

ERIC Educational Resources Information Center

Gullo, Shirna R.

2014-01-01

Computerized testing may be one solution to enhance performance on the curricular Health Education Systems Inc. (HESI) exam and the National Council Licensure Exam for Registered Nurses (NCLEX-RN). Due to the integration of improved technological processes and procedures in healthcare for computerized documentation and electronicmedical records,…

Ethnic-Racial Attitudes, Images, and Behavior by Verbal Associations. Technical Report.

ERIC Educational Resources Information Center

Szalay, Lorand B.; And Others

The investigations focused on two main subject areas. The first series of experiments explored the validity of verbal association based inferences as an attitude measure and predictor of behavior. When compared with paper-and-pencil methods, the association based attitude index (EDI) showed high positive correlation as a group measure and medium…

Computer Games Application within Alternative Classroom Goal Structures: Cognitive, Metacognitive, and Affective Evaluation

ERIC Educational Resources Information Center

Ke, Fengfeng

2008-01-01

This article reports findings on a study of educational computer games used within various classroom situations. Employing an across-stage, mixed method model, the study examined whether educational computer games, in comparison to traditional paper-and-pencil drills, would be more effective in facilitating comprehensive math learning outcomes,…

Examining Teachers' Behavioral Management Charts: A Comparison of Class Dojo and Paper-Pencil Methods

ERIC Educational Resources Information Center

Krach, S. Kathleen; McCreery, Michael P.; Rimel, Hillary

2017-01-01

Many teachers report using behavioral management charts in their classrooms as a means of managing student behaviors, but little is known about exactly what behaviors teachers are charting, or specifically how. Misunderstanding over how real-world teachers maintain behavioral charts may cause miscommunication between the teacher and the school…

A Comparison of Web-Based and Paper-and-Pencil Homework on Student Performance in College Algebra

ERIC Educational Resources Information Center

Hauk, Shandy; Powers, Robert A.; Segalla, Angelo

2015-01-01

College algebra fulfills general education requirements at many colleges in the United States. The study reported here investigated differences in mathematics achievement between undergraduates in college algebra classes using one of two homework methods: "WeBWorK," an open-source system for web-based homework, or traditional…

PC_Eyewitness and the sequential superiority effect: computer-based lineup administration.

PubMed

MacLin, Otto H; Zimmerman, Laura A; Malpass, Roy S

2005-06-01

Computer technology has become an increasingly important tool for conducting eyewitness identifications. In the area of lineup identifications, computerized administration offers several advantages for researchers and law enforcement. PC_Eyewitness is designed specifically to administer lineups. To assess this new lineup technology, two studies were conducted in order to replicate the results of previous studies comparing simultaneous and sequential lineups. One hundred twenty university students participated in each experiment. Experiment 1 used traditional paper-and-pencil lineup administration methods to compare simultaneous to sequential lineups. Experiment 2 used PC_Eyewitness to administer simultaneous and sequential lineups. The results of these studies were compared to the meta-analytic results reported by N. Steblay, J. Dysart, S. Fulero, and R. C. L. Lindsay (2001). No differences were found between paper-and-pencil and PC_Eyewitness lineup administration methods. The core findings of the N. Steblay et al. (2001) meta-analysis were replicated by both administration procedures. These results show that computerized lineup administration using PC_Eyewitness is an effective means for gathering eyewitness identification data.

Hexagonal pencil-like CdS nanorods: Facile synthesis and enhanced visible light photocatalytic performance

NASA Astrophysics Data System (ADS)

An, Liang; Wang, Guanghui; Zhao, Lei; Zhou, Yong; Gao, Fang; Cheng, Yang

2015-07-01

In the present study, hexagonal pencil-like CdS nanorods have been successfully synthesized through a typical facile and economical one-step hydrothermal method without using any surfactant or template. The product was characterized by X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and energy dispersive analysis of X-ray (EDX). The results revealed that the prepared CdS photocatalyst consisted of a large quantity of straight and smooth solid hexagonal nanorods and a few nanoparticles. The photocatalytic activities of CdS nanorods and commercial CdS powders were investigated by the photodegradation of Orange II (OII) in aqueous solution under visible light, and the CdS nanorods presented the highest photocatalytic activity. Its photocatalytic efficiency enhancement was attributed to the improved transmission of photogenerated electron-hole pairs in the CdS nanostructures. The present findings may provide a facile approach to synthesize high efficient CdS photocatalysts.

Writing Forces Associated With Four Pencil Grasp Patterns in Grade 4 Children

PubMed Central

Schwellnus, Heidi; Carnahan, Heather; Kushki, Azadeh; Polatajko, Helene; Missiuna, Cheryl

2013-01-01

OBJECTIVE. We investigated differences in handwriting kinetics, speed, and legibility among four pencil grasps after a 10-min copy task. METHOD. Seventy-four Grade 4 students completed a handwriting assessment before and after a copy task. Grip and axial forces were measured with an instrumented stylus and force-sensitive tablet. We used multiple linear regression to analyze the relationship between grasp pattern and grip and axial forces. RESULTS. We found no kinetic differences among grasps, whether considered individually or grouped by the number of fingers on the barrel. However, when grasps were grouped according to the thumb position, the adducted grasps exhibited higher mean grip and axial forces. CONCLUSION. Grip forces were generally similar across the different grasps. Kinetic differences resulting from thumb position seemed to have no bearing on speed and legibility. Interventions for handwriting difficulties should focus more on speed and letter formation than on grasp pattern. PMID:23433277

Internet Administration of Paper-and-Pencil Questionnaires Used in Couple Research: Assessing Psychometric Equivalence

ERIC Educational Resources Information Center

Brock, Rebecca L.; Barry, Robin A.; Lawrence, Erika; Dey, Jodi; Rolffs, Jaci

2012-01-01

This study examined the psychometric equivalence of paper-and-pencil and Internet formats of key questionnaires used in couple research. Self-report questionnaires assessing interpersonal constructs (relationship satisfaction, communication/conflict management, partner support, emotional intimacy) and intrapersonal constructs (individual traits,…

39. PENCIL SKETCH OF SELECTED DESIGN, DEPICTING OCEANGOING VESSEL (WHICH ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

39. PENCIL SKETCH OF SELECTED DESIGN, DEPICTING OCEAN-GOING VESSEL (WHICH WERE STILL NAVIGATING SACRAMENTO RIVER IN 1930s) APPROACHING LIFT SPAN Drawn by project architect Alfred Eichler, 1935 - Sacramento River Bridge, Spanning Sacramento River at California State Highway 275, Sacramento, Sacramento County, CA

Intranet Effectiveness: A Public Relations Paper-and-Pencil Checklist.

ERIC Educational Resources Information Center

Murgolo-Poore, Marie E.; Pitt, Leyland F.; Ewing, Michael T.

2002-01-01

Describes a process directed at developing a simple paper-and-pencil checklist to assess Intranet effectiveness. Discusses the checklist purification procedure, and attempts to establish reliability and validity for the list. Concludes by identifying managerial applications of the checklist, recognizing the limitations of the approach, and…

Do pencil-point spinal needles decrease the incidence of postdural puncture headache in reality? A comparative study between pencil-point 25G Whitacre and cutting-beveled 25G Quincke spinal needles in 320 obstetric patients.

PubMed

Pal, Anirban; Acharya, Amita; Pal, Nidhi Dawar; Dawn, Satrajit; Biswas, Jhuma

2011-01-01

Postdural puncture headache (PDPH) is a distressing complication of the subarachnoid block. The previous studies conducted, including the recent ones, do not conclusively prove that pencil-point spinal needles decrease the incidence of PDPH. In this study, we have tried to find out whether a pencil-point Whitacre needle is a better alternative than the classic cutting beveled, commonly used, Quincke spinal needle, in patients at risk of PDPH. Three hundred and twenty obstetric patients, 20-36 years of age, ASA I and II, posted for Cesarean section under subarachnoid block, were randomly assigned into two groups W and Q, where 25G Whitacre and 25G Quincke spinal needles were used, respectively. The primary objective of the study was to find out the difference in incidence of PDPH, if any, between the two groups, by using the t test and Chi square test. The incidence of PDPH was 5% in group W and 28.12% in group Q, and the difference in incidence was statistically significant (P<0.001). The pencil-point 25G Whitacre spinal needle causes less incidence of PDPH compared to the classic 25G Quincke needle, and is recommended for use in patients at risk of PDPH.

Robust infrared-shielding coating films prepared using perhydropolysilazane and hydrophobized indium tin oxide nanoparticles with tuned surface plasmon resonance.

PubMed

Katagiri, Kiyofumi; Takabatake, Ryuichi; Inumaru, Kei

2013-10-23

Robust infrared (IR)-shielding coating films were prepared by dispersing indium tin oxide (ITO) nanoparticles (NPs) in a silica matrix. Hydrophobized ITO NPs were synthesized via a liquid phase process. The surface plasmon resonance (SPR) absorption of the ITO NPs could be tuned by varying the concentration of Sn doping from 3 to 30 mol %. The shortest SPR wavelength and strongest SPR absorption were obtained for the ITO NPs doped with 10% Sn because they possessed the highest electron carrier density. Coating films composed of a continuous silica matrix homogeneously dispersed with ITO NPs were obtained using perhydropolysilazane (PHPS) as a precursor. PHPS was completely converted to silica by exposure to the vapor from aqueous ammonia at 50 °C. The prepared coating films can efficiently shield IR radiation even though they are more than 80% transparent in the visible range. The coating film with the greatest IR-shielding ability completely blocked IR light at wavelengths longer than 1400 nm. The pencil hardness of this coating film was 9H at a load of 750 g, which is sufficiently robust for applications such as automotive glass.

A dual-ion imprinted polymer embedded in sol-gel matrix for the ultra trace simultaneous analysis of cadmium and copper.

PubMed

Bali Prasad, Bhim; Jauhari, Darshika; Verma, Archana

2014-03-01

In simultaneous determination of group of elements, there are inter-metallic interactions which result in a non-linear relationship between the peak current and ionic concentration for each of the element, at bare (unmodified) electrode. To resolve this problem, we have resorted, for the first time, to develop a modified pencil graphite electrode using a typical ion imprinted polymer network (dual-ion imprinted polymer embedded in sol-gel matrix (inorganic-organic hybrid nano-material)) for the simultaneous analysis of a binary mixture of Cd(II) and Cu(II) ions, without any complication of inter-metallic interactions and competitive bindings, in real samples. The adequate resolution of differential pulse anodic stripping voltammetry peaks by 725 mV (cf, 615 mV with unmodified electrode), without any cross-reactivity and the stringent detection limits as low as, 0.050 and 0.034 ng mL(-1) (S/N=3) for Cd(II) and Cu(II) ions, respectively by the proposed sensor can be considered useful for the primitive diagnosis of several chronic diseases in clinical settings. Copyright © 2013 Elsevier B.V. All rights reserved.

A comparison of TPS and different measurement techniques in small-field electron beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donmez Kesen, Nazmiye, E-mail: nazo94@gmail.com; Cakir, Aydin; Okutan, Murat

In recent years, small-field electron beams have been used for the treatment of superficial lesions, which requires small circular fields. However, when using very small electron fields, some significant dosimetric problems may occur. In this study, dose distributions and outputs of circular fields with dimensions of 5 cm and smaller, for nominal energies of 6, 9, and 15 MeV from the Siemens ONCOR Linac, were measured and compared with data from a treatment planning system using the pencil-beam algorithm in electron beam calculations. All dose distribution measurements were performed using the Gafchromic EBT film; these measurements were compared with datamore » that were obtained from the Computerized Medical Systems (CMS) XiO treatment planning system (TPS), using the gamma-index method in the PTW VeriSoft software program. Output measurements were performed using the Gafchromic EBT film, an Advanced Markus ion chamber, and thermoluminescent dosimetry (TLD). Although the pencil-beam algorithm is used to model electron beams in many clinics, there is no substantial amount of detailed information in the literature about its use. As the field size decreased, the point of maximum dose moved closer to the surface. Output factors were consistent; differences from the values obtained from the TPS were, at maximum, 42% for 6 and 15 MeV and 32% for 9 MeV. When the dose distributions from the TPS were compared with the measurements from the Gafchromic EBT films, it was observed that the results were consistent for 2-cm diameter and larger fields, but the outputs for fields of 1-cm diameter and smaller were not consistent. In CMS XiO TPS, calculated using the pencil-beam algorithm, the dose distributions of electron treatment fields that were created with circular cutout of a 1-cm diameter were not appropriate for patient treatment and the pencil-beam algorithm is not convenient for monitor unit (MU) calculations in electron dosimetry.« less

MO-FG-CAMPUS-TeP3-03: Calculation of Proton Pencil Beam Properties with Full Beamline Model in TOPAS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wulff, J; Abel, E

2016-06-15

Purpose: Introducing Monte Carlo based dose calculation algorithms into proton therapy planning systems (TPS) leads to improved accuracy. However accurate modelling of the proton pencil beam impinging the patient is necessary. Current approaches rely on measurement-driven reconstruction of phase-space and spectrum properties, typically constrained to analytical model functions. In this study a detailed Monte Carlo model of the complete cyclotron-based delivery system was created with the aim of providing more representative beam properties at treatment position. Methods: A model of the Varian Probeam proton system from the cyclotron exit to isocenter was constructed in the TOPAS Monte Carlo framework. Themore » beam evolution through apertures and magnetic elements was validated using Transport/Turtle calculations and additionally against measurements from the Probeam™ system at Scripps Proton Therapy Center (SPTC) in San Diego, CA. A voxelized water phantom at isocenter allowed for comparison of the dose-depth curve from the Probeam model with that of a corresponding Gaussian beam over the entire energy range (70–240 MeV). Measurements of relative beam fluence cross-profiles and depth-dose curves at and around isocenter were also compared to the MC results. Results: The simulated TOPAS beam envelope was found to agree with both the Transport/Turtle and measurements to within 5% for most of the beamline. The MC predicted energy spectrum at isocenter was found to deviate increasingly from Gaussian at energies below 160 MeV. The corresponding effects on the depth dose curve agreed well with measurements. Conclusion: Given the flexibility of TOPAS and available details of the delivery system, an accurate characterization of a proton pencil beam at isocenter is possible. Incorporation of the MC derived properties of the proton pencil beam can eliminate analytical approximations and ultimately increase treatment plan accuracy and quality. Both authors are employees of Varian Medical Systems.« less

Robust Proton Pencil Beam Scanning Treatment Planning for Rectal Cancer Radiation Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blanco Kiely, Janid Patricia, E-mail: jkiely@sas.upenn.edu; White, Benjamin M.

2016-05-01

Purpose: To investigate, in a treatment plan design and robustness study, whether proton pencil beam scanning (PBS) has the potential to offer advantages, relative to interfraction uncertainties, over photon volumetric modulated arc therapy (VMAT) in a locally advanced rectal cancer patient population. Methods and Materials: Ten patients received a planning CT scan, followed by an average of 4 weekly offline CT verification CT scans, which were rigidly co-registered to the planning CT. Clinical PBS plans were generated on the planning CT, using a single-field uniform-dose technique with single-posterior and parallel-opposed (LAT) fields geometries. The VMAT plans were generated on the planningmore » CT using 2 6-MV, 220° coplanar arcs. Clinical plans were forward-calculated on verification CTs to assess robustness relative to anatomic changes. Setup errors were assessed by forward-calculating clinical plans with a ±5-mm (left–right, anterior–posterior, superior–inferior) isocenter shift on the planning CT. Differences in clinical target volume and organ at risk dose–volume histogram (DHV) indicators between plans were tested for significance using an appropriate Wilcoxon test (P<.05). Results: Dosimetrically, PBS plans were statistically different from VMAT plans, showing greater organ at risk sparing. However, the bladder was statistically identical among LAT and VMAT plans. The clinical target volume coverage was statistically identical among all plans. The robustness test found that all DVH indicators for PBS and VMAT plans were robust, except the LAT's genitalia (V5, V35). The verification CT plans showed that all DVH indicators were robust. Conclusions: Pencil beam scanning plans were found to be as robust as VMAT plans relative to interfractional changes during treatment when posterior beam angles and appropriate range margins are used. Pencil beam scanning dosimetric gains in the bowel (V15, V20) over VMAT suggest that using PBS to treat rectal cancer may reduce radiation treatment–related toxicity.« less

Pencil Size and Their Impact on Penmanship Legibility

ERIC Educational Resources Information Center

Sinclair, Becky; Szabo, Susan

2015-01-01

Legible penmanship is important. However, young students have difficulty producing legible handwriting (Marr, Windsor, & Cermak, 2001). As legible handwriting is a benefit for both the students and the teachers in the classroom setting, this study examined if pencil size had an impact on preschool and kindergarten students' handwriting. The…

76 FR 38697 - Cased Pencils From China

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-01

... China Determination On the basis of the record \\1\\ developed in the subject five-year review, the United... China would be likely to lead to continuation or recurrence of material injury to an industry in the... Publication 4239 (June 2011), entitled Cased Pencils from China: Investigation No. 731-TA-669 (Third Review...

41 CFR 101-25.107 - Guidelines for requisitioning and proper use of consumable or low cost items.

Code of Federal Regulations, 2011 CFR

2011-07-01

... needs. Attache cases, Ball point pens and refills, Brief cases, Binders, Carbon paper, Dictionaries, Felt tip markers, Felt tip pens and refills, File folders, Letterex, Letter openers, Pads (paper), Paper clips, Pencils, Pencil sharpeners, Portfolios (leather, plastic, and writing pads), Rubber bands...

41 CFR 101-25.107 - Guidelines for requisitioning and proper use of consumable or low cost items.

Code of Federal Regulations, 2012 CFR

2012-07-01

... needs. Attache cases, Ball point pens and refills, Brief cases, Binders, Carbon paper, Dictionaries, Felt tip markers, Felt tip pens and refills, File folders, Letterex, Letter openers, Pads (paper), Paper clips, Pencils, Pencil sharpeners, Portfolios (leather, plastic, and writing pads), Rubber bands...

41 CFR 101-25.107 - Guidelines for requisitioning and proper use of consumable or low cost items.

Code of Federal Regulations, 2014 CFR

2014-07-01

... needs. Attache cases, Ball point pens and refills, Brief cases, Binders, Carbon paper, Dictionaries, Felt tip markers, Felt tip pens and refills, File folders, Letterex, Letter openers, Pads (paper), Paper clips, Pencils, Pencil sharpeners, Portfolios (leather, plastic, and writing pads), Rubber bands...

41 CFR 101-25.107 - Guidelines for requisitioning and proper use of consumable or low cost items.

Code of Federal Regulations, 2013 CFR

2013-07-01

... needs. Attache cases, Ball point pens and refills, Brief cases, Binders, Carbon paper, Dictionaries, Felt tip markers, Felt tip pens and refills, File folders, Letterex, Letter openers, Pads (paper), Paper clips, Pencils, Pencil sharpeners, Portfolios (leather, plastic, and writing pads), Rubber bands...

Nursing students' perceptions of high- and low-fidelity simulation used as learning methods.

PubMed

Tosterud, Randi; Hedelin, Birgitta; Hall-Lord, Marie Louise

2013-07-01

Due to the increasing focus on simulation used in nursing education, there is a need to examine how the scenarios and different simulation methods used are perceived by students. The aim of this study was to examine nursing students' perceptions of scenarios played out in different simulation methods, and whether their educational level influenced their perception. The study had a quantitative, evaluative and comparative design. The sample consisted of baccalaureate nursing students (n = 86) within various educational levels. The students were randomly divided into groups. They solved a patient case adapted to their educational level by using a high-fidelity patient simulator, a static mannequin or a paper/pencil case study. Data were collected by three instruments developed by the National League for Nursing. The results showed that the nursing students reported satisfaction with the implementation of the scenarios regardless of the simulation methods used. The findings indicated that the students who used the paper/pencil case study were the most satisfied. Moreover, educational level did not seem to influence their perceptions. Independent of educational level, the findings indicated that simulation with various degrees of fidelity could be used in nursing education. There is a need for further research to examine more closely the rationale behind the students' perception of the simulation methods. Copyright © 2013 Elsevier Ltd. All rights reserved.

A Comparison of the Pencil-of-Function Method with Prony’s Method, Wiener Filters and Other Identification Techniques,

DTIC Science & Technology

1977-12-01

exponentials encountered are complex and zhey are approximately at harmonic frequencies. Moreover, the real parts of the complex exponencials are much...functions as a basis for expanding the current distribution on an antenna by the method of moments results in a regularized ill-posed problem with respect...to the current distribution on the antenna structure. However, the problem is not regularized with respect to chaoge because the chaPge distribution

Multidimensional CAT Item Selection Methods for Domain Scores and Composite Scores: Theory and Applications

ERIC Educational Resources Information Center

Yao, Lihua

2012-01-01

Multidimensional computer adaptive testing (MCAT) can provide higher precision and reliability or reduce test length when compared with unidimensional CAT or with the paper-and-pencil test. This study compared five item selection procedures in the MCAT framework for both domain scores and overall scores through simulation by varying the structure…

Parallel Symmetric Eigenvalue Problem Solvers

DTIC Science & Technology

2015-05-01

get research, tutoring, and mentoring experience as an undergraduate. Last but not least, I thank my family for their love and support. v TABLE OF...32 4.6.2 Choice of the Ritz shifts . . . . . . . . . . . . . . . . . . . . 37 4.7 Relationship between...pencil. I will conclude with a discussion of the relationship between Trace- Min and simultaneous iteration. If both methods solve the linear systems

Beyond Metaphor Drawings to Envisage Integration of HIV & AIDS Education: A Self-Study in Primary Mathematics Teacher Education

ERIC Educational Resources Information Center

van Laren, Linda

2014-01-01

Researchers using participatory methods that are engaging, purposeful and facilitate social change may need further pragmatic strategies to encourage the required change. Using pencil-and-paper drawings to introduce HIV & AIDS integration in a discipline such as Mathematics Education is an innovative participatory strategy to initiate change.…

The Neglected "R": Improving Writing Instruction through iPad Apps

ERIC Educational Resources Information Center

Sessions, Laird; Kang, Mi Ok; Womack, Sue

2016-01-01

In this study the authors investigated the effects of integrating iPad applications into writing instruction for fifth grade students. By comparing the writing of students taught with paper and pencil methods with that of students utilizing the iPad writing applications, two research questions guided the study: (1) Are there differences in student…

The Future Value of Serious Games for Assessment: Where Do We Go Now?

ERIC Educational Resources Information Center

de Klerk, Sebastiaan; Kato, Pamela M.

2017-01-01

Game-based assessments will most likely be an increasing part of testing programs in future generations because they provide promising possibilities for more valid and reliable measurement of students' skills as compared to the traditional methods of assessment like paper-and-pencil tests or performance-based assessments. The current status of…

D'Nealian Handwriting versus Circle-Stick Print.

ERIC Educational Resources Information Center

Thurber, Donald N.

This paper argues against teaching children to make letters using circle-stick writing. It contends that the circle-stick method requires continued pen/pencil lifts hindering rhythm or flow in the writing process and that there is little carry-over value into cursive writing as the two scripts are totally different. D'Nealian print, one type of…

76 FR 27988 - Certain Cased Pencils From the People's Republic of China: Final Results of the Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-13

... any fashion, and either sharpened or unsharpened. The pencils subject to the order are currently...'') of their responsibility concerning the return or destruction of proprietary information disclosed under the APO in accordance with 19 CFR 351.305. Timely written notification of the return or...

Equivalent Expressions Using CAS and Paper-and-Pencil Techniques

ERIC Educational Resources Information Center

Fonger, Nicole L.

2014-01-01

How can the key concept of equivalent expressions be addressed so that students strengthen their representational fluency with symbols, graphs, and numbers? How can research inform the synergistic use of both paper-and-pencil analysis and computer algebra systems (CAS) in a classroom learning environment? These and other related questions have…

Pencil-Free Homework: Worth Considering?

ERIC Educational Resources Information Center

Forster, Colin

2016-01-01

After spending most of the day in school, children are typically given additional assignments to be completed at home. The author and colleagues developed a series of science homework tasks for use in primary schools. The difference with these homework tasks, however, was that they were pencil-free: no blank spaces for the children to fill in and…

A "Rearrangement Procedure" for Scoring Adaptive Tests with Review Options.

ERIC Educational Resources Information Center

Papanastasiou, Elena C.

Due to the increased popularity of computerized adaptive testing (CAT), many admissions tests, as well as certification and licensure examinations, have been transformed from their paper-and-pencil versions to computerized adaptive versions. A major difference between paper-and-pencil tests and CAT, from an examinees point of view, is that in many…

A "Rearrangement Procedure" for Scoring Adaptive Tests with Review Options

ERIC Educational Resources Information Center

Papanastasiou, Elena C.; Reckase, Mark D.

2007-01-01

Because of the increased popularity of computerized adaptive testing (CAT), many admissions tests, as well as certification and licensure examinations, have been transformed from their paper-and-pencil versions to computerized adaptive versions. A major difference between paper-and-pencil tests and CAT from an examinee's point of view is that in…

Comparing Student Performance on Paper-and-Pencil and Computer-Based-Tests

ERIC Educational Resources Information Center

Hardcastle, Joseph; Herrmann-Abell, Cari F.; DeBoer, George E.

2017-01-01

Can student performance on computer-based tests (CBT) and paper-and-pencil tests (PPT) be considered equivalent measures of student knowledge? States and school districts are grappling with this question, and although studies addressing this question are growing, additional research is needed. We report on the performance of students who took…

My Pencils Have Names

ERIC Educational Resources Information Center

Block, Phillip

2011-01-01

As personal computers have evolved steadily into handhelds and teachers continue the march toward lining the walls of the classroom with flat screen work stations, many assume that the old-timey "number 2" lead yellow pencil is probably on the high road to extinction. Yet most classrooms still flow with them like miniature telephone poles fresh…

School-Supply Artists

ERIC Educational Resources Information Center

Szekely, George

2009-01-01

In school, the author sat next to Sandor the sculptor--when he was still undiscovered. He could take a pencil and, while seemingly listening in class, completely reshape the pencil by biting it. To detail his best pieces, Sandor would highlight the dents and gnashes with colored pens. Little did Sandor realize that his early efforts would be an…

Graphite Based Electrode for ECG Monitoring: Evaluation under Freshwater and Saltwater Conditions.

PubMed

Thap, Tharoeun; Yoon, Kwon-Ha; Lee, Jinseok

2016-04-15

We proposed new electrodes that are applicable for electrocardiogram (ECG) monitoring under freshwater- and saltwater-immersion conditions. Our proposed electrodes are made of graphite pencil lead (GPL), a general-purpose writing pencil. We have fabricated two types of electrode: a pencil lead solid type (PLS) electrode and a pencil lead powder type (PLP) electrode. In order to assess the qualities of the PLS and PLP electrodes, we compared their performance with that of a commercial Ag/AgCl electrode, under a total of seven different conditions: dry, freshwater immersion with/without movement, post-freshwater wet condition, saltwater immersion with/without movement, and post-saltwater wet condition. In both dry and post-freshwater wet conditions, all ECG-recorded PQRST waves were clearly discernible, with all types of electrodes, Ag/AgCl, PLS, and PLP. On the other hand, under the freshwater- and saltwater-immersion conditions with/without movement, as well as post-saltwater wet conditions, we found that the proposed PLS and PLP electrodes provided better ECG waveform quality, with significant statistical differences compared with the quality provided by Ag/AgCl electrodes.

Design, Development and Operational Experience of Demonstration Facility for Cs-137 Source Pencil Production at Trombay - 13283

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patil, S.B.; Srivastava, P.; Mishra, S.K.

2013-07-01

Radioactive waste management is a vital aspect of any nuclear program. The commercial feasibility of the nuclear program largely depends on the efficiency of the waste management techniques. One of such techniques is the separation of high yield radio-nuclides from the waste and making it suitable for medical and industrial applications. This will give societal benefit in addition to revenue generation. Co-60, the isotope presently being used for medical applications, needs frequent replacement because of its short half life. Cs-137, the major constituent of the nuclear waste, is a suitable substitute for Co-60 as a radioactive source because of itsmore » longer half life (28 years). Indian nuclear waste management program has given special emphasis on utilization of Cs-137 for such applications. In view of this a demonstration facility has been designed for vitrification of Cs-137 in borosilicate glass, cast in stainless steel pencils, to be used as source pencils of 300 Ci strength for blood irradiation. An induction heated metallic melter of suitable capacity has been custom designed for the application and employed for the Cs-137 pencil fabrication facility. This article describes various systems, design features, experiments and resulting modifications, observations and remote handling features necessary for the actual operation of such facility. The layout of the facility has been planned in such a way that the same can be adopted in a hot cell for commercial production of source pencils. (authors)« less

Geometrization and Generalization of the Kowalevski Top

NASA Astrophysics Data System (ADS)

Dragović, Vladimir

2010-08-01

A new view on the Kowalevski top and the Kowalevski integration procedure is presented. For more than a century, the Kowalevski 1889 case, has attracted full attention of a wide community as the highlight of the classical theory of integrable systems. Despite hundreds of papers on the subject, the Kowalevski integration is still understood as a magic recipe, an unbelievable sequence of skillful tricks, unexpected identities and smart changes of variables. The novelty of our present approach is based on our four observations. The first one is that the so-called fundamental Kowalevski equation is an instance of a pencil equation of the theory of conics which leads us to a new geometric interpretation of the Kowalevski variables w, x 1, x 2 as the pencil parameter and the Darboux coordinates, respectively. The second is observation of the key algebraic property of the pencil equation which is followed by introduction and study of a new class of discriminantly separable polynomials. All steps of the Kowalevski integration procedure are now derived as easy and transparent logical consequences of our theory of discriminantly separable polynomials. The third observation connects the Kowalevski integration and the pencil equation with the theory of multi-valued groups. The Kowalevski change of variables is now recognized as an example of a two-valued group operation and its action. The final observation is surprising equivalence of the associativity of the two-valued group operation and its action to the n = 3 case of the Great Poncelet Theorem for pencils of conics.

Quantifying the effect of air gap, depth, and range shifter thickness on TPS dosimetric accuracy in superficial PBS proton therapy.

PubMed

Shirey, Robert J; Wu, Hsinshun Terry

2018-01-01

This study quantifies the dosimetric accuracy of a commercial treatment planning system as functions of treatment depth, air gap, and range shifter thickness for superficial pencil beam scanning proton therapy treatments. The RayStation 6 pencil beam and Monte Carlo dose engines were each used to calculate the dose distributions for a single treatment plan with varying range shifter air gaps. Central axis dose values extracted from each of the calculated plans were compared to dose values measured with a calibrated PTW Markus chamber at various depths in RW3 solid water. Dose was measured at 12 depths, ranging from the surface to 5 cm, for each of the 18 different air gaps, which ranged from 0.5 to 28 cm. TPS dosimetric accuracy, defined as the ratio of calculated dose relative to the measured dose, was plotted as functions of depth and air gap for the pencil beam and Monte Carlo dose algorithms. The accuracy of the TPS pencil beam dose algorithm was found to be clinically unacceptable at depths shallower than 3 cm with air gaps wider than 10 cm, and increased range shifter thickness only added to the dosimetric inaccuracy of the pencil beam algorithm. Each configuration calculated with Monte Carlo was determined to be clinically acceptable. Further comparisons of the Monte Carlo dose algorithm to the measured spread-out Bragg Peaks of multiple fields used during machine commissioning verified the dosimetric accuracy of Monte Carlo in a variety of beam energies and field sizes. Discrepancies between measured and TPS calculated dose values can mainly be attributed to the ability (or lack thereof) of the TPS pencil beam dose algorithm to properly model secondary proton scatter generated in the range shifter. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

Neutrons in proton pencil beam scanning: parameterization of energy, quality factors and RBE

NASA Astrophysics Data System (ADS)

Schneider, Uwe; Hälg, Roger A.; Baiocco, Giorgio; Lomax, Tony

2016-08-01

The biological effectiveness of neutrons produced during proton therapy in inducing cancer is unknown, but potentially large. In particular, since neutron biological effectiveness is energy dependent, it is necessary to estimate, besides the dose, also the energy spectra, in order to obtain quantities which could be a measure of the biological effectiveness and test current models and new approaches against epidemiological studies on cancer induction after proton therapy. For patients treated with proton pencil beam scanning, this work aims to predict the spatially localized neutron energies, the effective quality factor, the weighting factor according to ICRP, and two RBE values, the first obtained from the saturation corrected dose mean lineal energy and the second from DSB cluster induction. A proton pencil beam was Monte Carlo simulated using GEANT. Based on the simulated neutron spectra for three different proton beam energies a parameterization of energy, quality factors and RBE was calculated. The pencil beam algorithm used for treatment planning at PSI has been extended using the developed parameterizations in order to calculate the spatially localized neutron energy, quality factors and RBE for each treated patient. The parameterization represents the simple quantification of neutron energy in two energy bins and the quality factors and RBE with a satisfying precision up to 85 cm away from the proton pencil beam when compared to the results based on 3D Monte Carlo simulations. The root mean square error of the energy estimate between Monte Carlo simulation based results and the parameterization is 3.9%. For the quality factors and RBE estimates it is smaller than 0.9%. The model was successfully integrated into the PSI treatment planning system. It was found that the parameterizations for neutron energy, quality factors and RBE were independent of proton energy in the investigated energy range of interest for proton therapy. The pencil beam algorithm has been extended using the developed parameterizations in order to calculate the neutron energy, quality factor and RBE.

Neutrons in proton pencil beam scanning: parameterization of energy, quality factors and RBE.

PubMed

Schneider, Uwe; Hälg, Roger A; Baiocco, Giorgio; Lomax, Tony

2016-08-21

The biological effectiveness of neutrons produced during proton therapy in inducing cancer is unknown, but potentially large. In particular, since neutron biological effectiveness is energy dependent, it is necessary to estimate, besides the dose, also the energy spectra, in order to obtain quantities which could be a measure of the biological effectiveness and test current models and new approaches against epidemiological studies on cancer induction after proton therapy. For patients treated with proton pencil beam scanning, this work aims to predict the spatially localized neutron energies, the effective quality factor, the weighting factor according to ICRP, and two RBE values, the first obtained from the saturation corrected dose mean lineal energy and the second from DSB cluster induction. A proton pencil beam was Monte Carlo simulated using GEANT. Based on the simulated neutron spectra for three different proton beam energies a parameterization of energy, quality factors and RBE was calculated. The pencil beam algorithm used for treatment planning at PSI has been extended using the developed parameterizations in order to calculate the spatially localized neutron energy, quality factors and RBE for each treated patient. The parameterization represents the simple quantification of neutron energy in two energy bins and the quality factors and RBE with a satisfying precision up to 85 cm away from the proton pencil beam when compared to the results based on 3D Monte Carlo simulations. The root mean square error of the energy estimate between Monte Carlo simulation based results and the parameterization is 3.9%. For the quality factors and RBE estimates it is smaller than 0.9%. The model was successfully integrated into the PSI treatment planning system. It was found that the parameterizations for neutron energy, quality factors and RBE were independent of proton energy in the investigated energy range of interest for proton therapy. The pencil beam algorithm has been extended using the developed parameterizations in order to calculate the neutron energy, quality factor and RBE.

Development of activity pencil beam algorithm using measured distribution data of positron emitter nuclei generated by proton irradiation of targets containing (12)C, (16)O, and (40)Ca nuclei in preparation of clinical application.

PubMed

Miyatake, Aya; Nishio, Teiji; Ogino, Takashi

2011-10-01

The purpose of this study is to develop a new calculation algorithm that is satisfactory in terms of the requirements for both accuracy and calculation time for a simulation of imaging of the proton-irradiated volume in a patient body in clinical proton therapy. The activity pencil beam algorithm (APB algorithm), which is a new technique to apply the pencil beam algorithm generally used for proton dose calculations in proton therapy to the calculation of activity distributions, was developed as a calculation algorithm of the activity distributions formed by positron emitter nuclei generated from target nuclear fragment reactions. In the APB algorithm, activity distributions are calculated using an activity pencil beam kernel. In addition, the activity pencil beam kernel is constructed using measured activity distributions in the depth direction and calculations in the lateral direction. (12)C, (16)O, and (40)Ca nuclei were determined as the major target nuclei that constitute a human body that are of relevance for calculation of activity distributions. In this study, "virtual positron emitter nuclei" was defined as the integral yield of various positron emitter nuclei generated from each target nucleus by target nuclear fragment reactions with irradiated proton beam. Compounds, namely, polyethylene, water (including some gelatin) and calcium oxide, which contain plenty of the target nuclei, were irradiated using a proton beam. In addition, depth activity distributions of virtual positron emitter nuclei generated in each compound from target nuclear fragment reactions were measured using a beam ON-LINE PET system mounted a rotating gantry port (BOLPs-RGp). The measured activity distributions depend on depth or, in other words, energy. The irradiated proton beam energies were 138, 179, and 223 MeV, and measurement time was about 5 h until the measured activity reached the background level. Furthermore, the activity pencil beam data were made using the activity pencil beam kernel, which was composed of the measured depth data and the lateral data including multiple Coulomb scattering approximated by the Gaussian function, and were used for calculating activity distributions. The data of measured depth activity distributions for every target nucleus by proton beam energy were obtained using BOLPs-RGp. The form of the depth activity distribution was verified, and the data were made in consideration of the time-dependent change of the form. Time dependence of an activity distribution form could be represented by two half-lives. Gaussian form of the lateral distribution of the activity pencil beam kernel was decided by the effect of multiple Coulomb scattering. Thus, the data of activity pencil beam involving time dependence could be obtained in this study. The simulation of imaging of the proton-irradiated volume in a patient body using target nuclear fragment reactions was feasible with the developed APB algorithm taking time dependence into account. With the use of the APB algorithm, it was suggested that a system of simulation of activity distributions that has levels of both accuracy and calculation time appropriate for clinical use can be constructed.

Using Perturbed QR Factorizations To Solve Linear Least-Squares Problems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Avron, Haim; Ng, Esmond G.; Toledo, Sivan

2008-03-21

We propose and analyze a new tool to help solve sparse linear least-squares problems min{sub x} {parallel}Ax-b{parallel}{sub 2}. Our method is based on a sparse QR factorization of a low-rank perturbation {cflx A} of A. More precisely, we show that the R factor of {cflx A} is an effective preconditioner for the least-squares problem min{sub x} {parallel}Ax-b{parallel}{sub 2}, when solved using LSQR. We propose applications for the new technique. When A is rank deficient we can add rows to ensure that the preconditioner is well-conditioned without column pivoting. When A is sparse except for a few dense rows we canmore » drop these dense rows from A to obtain {cflx A}. Another application is solving an updated or downdated problem. If R is a good preconditioner for the original problem A, it is a good preconditioner for the updated/downdated problem {cflx A}. We can also solve what-if scenarios, where we want to find the solution if a column of the original matrix is changed/removed. We present a spectral theory that analyzes the generalized spectrum of the pencil (A*A,R*R) and analyze the applications.« less

Determination of atropine sulfate using a novel sensitive DNA-biosensor based on its interaction on a modified pencil graphite electrode.

PubMed

Ensafi, Ali A; Nasr-Esfahani, Parisa; Heydari-Bafrooei, Esmaeil; Rezaei, B

2015-01-01

A novel, selective, rapid and simple electrochemical method is developed for the determination of atropine sulfate. UV-Vis and differential pulse voltammetry are used to study the interaction of atropine sulfate with salmon sperm ds-DNA on the surface of salmon sperm ds-DNA modified-pencil graphite electrode (PGE). For this purpose, a pencil graphite electrode (PGE) modified with multiwall carbon nanotubes (MWCNTs), titanium dioxide nanoparticles (TiO2NPs), and poly-dialyldimethylammonium chloride (PDDA) decorated with ds-DNA is tested for the determination of atropine sulfate. The electrochemical oxidation peak current of adenine and guanine bonded on the surface of ds-DNA/PDDA-TiO2NPs-MWCNTs/PGE is used to obtain the analytical signal. Decreases in the intensities of guanine and adenine oxidation signals after their interaction with atropine sulfate are used as indicator signals for the sensitive determination of atropine sulfate. Using ds-DNA/PDDA-TiO2NPs-MWCNTs/PGE and based on the guanine signal, linear calibration curves were obtained in the range of 0.6 to 30.0 μmol L(-1) and 30.0 to 600.0 μmol L(-1) atropine sulfate with low detection limits of 30.0 nmol L(-1). The biosensor shows a good selectivity for the determination of atropine sulfate. Finally, the applicability of the biosensor is evaluated by measuring atropine sulfate in real samples with good accuracy. Copyright © 2014 Elsevier B.V. All rights reserved.

A validity study of two paper-pencil tests of concrete and formal operations

NASA Astrophysics Data System (ADS)

Farmer, Walter A.; Farrell, Margaret A.; Clark, Richard M.; McDonald, Janet

Two group paper-pencil batteries, the Longeot (consisting of three subtests) and three puzzles (KLR) from Science Teaching and the Development of Reasoning, were administered to 607 students from ninth and tenth grade mathematics and science classes. A subsample of 69 students was then administered three Inhelder tasks (chemicals, rods, and shadows). In general, the expected developmental trends were confirmed, with formal status being most difficult to attain on the Inhelder tasks and easiest to attain on the Longeot. The correlations between the KLR and Inhelder (0.61, p < 0.01) and the Longeot and Inhelder (0.55, p < 0.05) were moderately high. According to the method of Shayer (Note 2), it was found that each of five paper-pencil subtests discriminates at or between the 2B (late concrete) and 3A (early formal) levels while the sixth subtest, the mealworm puzzle, was found to discriminate at the 3A level. This study indicates that either group battery may be useful in identifying transitional subjects. However, if a more stringent criterion of formal is needed, a success rate of four or five out of the six subtests may be required. Both group batteries are relatively easy to administer and score with a minimum of guidance, although the KLR scoring might need to be simplified for use by the practitioner. Sex differences found on the KLR and the Longeot are suggestive of the potential differential use of these tests by researchers investigating sex differences in achievement or aptitude.

Comparing Computer-Supported Dynamic Modeling and "Paper & Pencil" Concept Mapping Technique in Students' Collaborative Activity

ERIC Educational Resources Information Center

Komis, Vassilis; Ergazaki, Marida; Zogza, Vassiliki

2007-01-01

This study aims at highlighting the collaborative activity of two high school students (age 14) in the cases of modeling the complex biological process of plant growth with two different tools: the "paper & pencil" concept mapping technique and the computer-supported educational environment "ModelsCreator". Students' shared activity in both cases…

Word Processor versus "The Pencil" Effects on Writing.

ERIC Educational Resources Information Center

Schanck, Emily T.

In a study to determine the effects of writing on the computer versus traditional writing by hand, 22 fourth grade students were randomly assigned to samples using either a computer or paper and pencil. The study hypothesized that (1) children are not more willing to revise and improve their writing using a word processor when compared to the…

76 FR 57017 - Certain Cased Pencils From the People's Republic of China: Notice of Court Decision Not in...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-15

... the People's Republic of China: Notice of Court Decision Not in Harmony With Final Results of... Republic of China covering the period of review (``POR'') of December 1, 2006, through November 30, 2007 with respect to Rongxin. See Certain Cased Pencils from the People's Republic of China: Final Results...

Allocation of Attention and Effect of Practice on Persons with and without Mental Retardation

ERIC Educational Resources Information Center

Oka, Kohei; Miura, Toshiaki

2008-01-01

Persons with mild and moderate mental retardation and CA-matched persons without mental retardation performed a dual-task, "pencil-and-paper task" (Baddeley, Della Sala, Gray, Papagno, & Spinnler (1997). Testing central executive functioning with a pencil-and-paper test. In Rabbit (Ed.), Methodology of Frontal and Executive Function (pp. 61-80).…

Instructional Supports for Representational Fluency in Solving Linear Equations with Computer Algebra Systems and Paper-and-Pencil

ERIC Educational Resources Information Center

Fonger, Nicole L.; Davis, Jon D.; Rohwer, Mary Lou

2018-01-01

This research addresses the issue of how to support students' representational fluency--the ability to create, move within, translate across, and derive meaning from external representations of mathematical ideas. The context of solving linear equations in a combined computer algebra system (CAS) and paper-and-pencil classroom environment is…

Beyond the Pencil

ERIC Educational Resources Information Center

Sands, Ian

2012-01-01

To the general public, the topic of art education conjures up images of pencil drawings and tempera paint. If asked what a student might learn in an art class, a typical response might be that they will be taught how to draw and paint. This interpretation isn't totally incorrect, as drawing and painting are activities preformed in most artrooms.…

Comparability of Online and Paper/Pencil Mathematics Performance Measures

ERIC Educational Resources Information Center

Moon, John L.

2013-01-01

The purpose of this study was to investigate the relationship between student mathematics performance of 4th, 8th, and 11th grade students in Nebraska and the mode of test administration, online and paper-pencil. Schools were allowed to select the mode of test administration for their school with some exceptions for students needing…

Investigating Plane Geometry Problem-Solving Strategies of Prospective Mathematics Teachers in Technology and Paper-and-Pencil Environments

ERIC Educational Resources Information Center

Koyuncu, Ilhan; Akyuz, Didem; Cakiroglu, Erdinc

2015-01-01

This study aims to investigate plane geometry problem-solving strategies of prospective mathematics teachers using dynamic geometry software (DGS) and paper-and-pencil (PPB) environments after receiving an instruction with GeoGebra (GGB). Four plane geometry problems were used in a multiple case study design to understand the solution strategies…

5 CFR 2634.304 - Gifts and reimbursements.

Code of Federal Regulations, 2013 CFR

2013-01-01

.... Example 1. An official accepts a print, a pen and pencil set, and a letter opener from a community service...: $185 Gift 3—Letter opener: $20 The official must disclose Gifts 1 and 2, since together they aggregate.... Example. Items such as a pen and pencil set, letter opener, leather case or engraved pen are generally...

5 CFR 2634.304 - Gifts and reimbursements.

Code of Federal Regulations, 2012 CFR

2012-01-01

.... Example 1. An official accepts a print, a pen and pencil set, and a letter opener from a community service...: $185 Gift 3—Letter opener: $20 The official must disclose Gifts 1 and 2, since together they aggregate.... Example. Items such as a pen and pencil set, letter opener, leather case or engraved pen are generally...

5 CFR 2634.304 - Gifts and reimbursements.

Code of Federal Regulations, 2014 CFR

2014-01-01

.... Example 1. An official accepts a print, a pen and pencil set, and a letter opener from a community service...: $185 Gift 3—Letter opener: $20 The official must disclose Gifts 1 and 2, since together they aggregate.... Example. Items such as a pen and pencil set, letter opener, leather case or engraved pen are generally...

Dynamic shear-lag model for understanding the role of matrix in energy dissipation in fiber-reinforced composites.

PubMed

Liu, Junjie; Zhu, Wenqing; Yu, Zhongliang; Wei, Xiaoding

2018-07-01

Lightweight and high impact performance composite design is a big challenge for scientists and engineers. Inspired from well-known biological materials, e.g., the bones, spider silk, and claws of mantis shrimp, artificial composites have been synthesized for engineering applications. Presently, the design of ballistic resistant composites mainly emphasizes the utilization of light and high-strength fibers, whereas the contribution from matrix materials receives less attention. However, recent ballistic experiments on fiber-reinforced composites challenge our common sense. The use of matrix with "low-grade" properties enhances effectively the impact performance. In this study, we establish a dynamic shear-lag model to explore the energy dissipation through viscous matrix materials in fiber-reinforced composites and the associations of energy dissipation characteristics with the properties and geometries of constituents. The model suggests that an enhancement in energy dissipation before the material integrity is lost can be achieved by tuning the shear modulus and viscosity of a matrix. Furthermore, our model implies that an appropriately designed staggered microstructure, adopted by many natural composites, can repeatedly activate the energy dissipation process and thus improve dramatically the impact performance. This model demonstrates the role of matrix in energy dissipation, and stimulates new advanced material design concepts for ballistic applications. Biological composites found in nature often possess exceptional mechanical properties that man-made materials haven't be able to achieve. For example, it is predicted that a pencil thick spider silk thread can stop a flying Boeing airplane. Here, by proposing a dynamic shear-lag model, we investigate the relationships between the impact performance of a composite with the dimensions and properties of its constituents. Our analysis suggests that the impact performance of fiber-reinforced composites could improve surprisingly with "low-grade" matrix materials, and discontinuities (often regarded as "defects") may play an important role in energy dissipation. Counter-intuitive as it may seem, our work helps understanding the secrets of the outstanding dynamic properties of some biological materials, and inspire novel ideas for man-made composites. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

SU-E-T-441: Comparison of Dose Distributions for Spot-Scanned Pencil-Beam and Scattered-Beam Proton Treatments of Ocular Tumors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deisher, A; Whitaker, T; Kruse, J

2014-06-01

Purpose: To study the cross-field and depth dose profiles of spot-scanned pencil beam configurations for the treatment of ocular tumors and to compare their performance to a simulated scattered beam. Methods: Dose distributions in a cubic water phantom were compared for beams that passed through a final 24mm diameter aperture to deposit maximum dose at 2.4cm depth. The pencil-beam spots formed a hexagonally-packed ring with a center-to-center spacing of 4mm. The protons exited the nozzle with energy 95.5MeV, traversed a 4.5cm water-equivalent range shifter, and travelled either 42.5cm or 100cm to the phantom surface. The aperture-to-phantom distance (APD) was 5.7cmmore » to allow room for eye-tracking hardware. A configuration with APD=0 was also tested. The scattered beam was generated with energy 159MeV, passed through 127mm of Lexan, exited the final aperture, and travelled 5.7cm to the phantom surface. This latter configuration is comparable to the MGH single scattered beamline. All beams were modelled with TOPAS1.0-beta6 compiled with GEANT4.9.6p2. Results: The modeled scattered beam produced a distal fall-off along the central axis of zd90%-zd10%=3.6mm. For the pencil beam, the zd90%-zd10% was 1.6mm in all configurations. The scattered beam's cross-field penumbra at depth of maximum dose was r90%- r10%=1.9mm. For the spot-scanned configuration with the range-shifter-tophantom distance (RsPD) of 100cm, similar cross-field profiles were achieved with r90%-r10%=2.0mm. At shorter RsPD of 42.5cm, the crossfield penumbras were 5.6mm and 7.7mm for APD=0cm and APD=5.7cm, respectively. Conclusion: For proton treatments employing a range shifter, the cross-field and central axis dose profiles depend on the quality of the original beam, the size of the range shifter, the distance from the range shifter exit to the patient, and the distance from the final aperture to the patient. A spot-scanned pencil beam configuration can achieve cross-field penumbras equal to a scattered beam and superior distal gradients.« less

Acoustic guided waves in cylindrical solid-fluid structures: Modeling with a sweeping frequency finite element method and experimental validation

NASA Astrophysics Data System (ADS)

Liu, Yang; D'Angelo, Ralph M.; Sinha, Bikash K.; Zeroug, Smaine

2017-02-01

Modeling and understanding the complex elastic-wave physics prevalent in solid-fluid cylindrically-layered structures is of importance in many NDE fields, and most pertinently in the domain of well integrity evaluation of cased holes in the oil and gas industry. Current sonic measurements provide viable techniques for well integrity evaluation yet their practical effectiveness is hampered by the current lack of knowledge of acoustic wave fields particularly in complicated cased-hole geometry where for instance two or more nested steel strings are present in the borehole. In this article, we propose and implement a Sweeping Frequency Finite Element Method (SFFEM) for acoustic guided waves simulation in complex geometries that include double steel strings cemented to each other and to the formation and where the strings may be non-concentric. Transient dynamic finite element models are constructed with sweeping frequency signals being applied as the excitation sources. The sources and receivers disposition simulate current sonic measurement tools deployed in the oilfield. Synthetic wavetrains are recorded and processed with modified matrix pencil method to isolate both the dispersive and non-dispersive propagating guided wave modes. Scaled experiments of fluid-filled double strings with dimensions mimicking the real ones encountered in the field have also been carried out to generate reference data. A comparison of the experimental and numerical results indicates that the SFFEM is capable of accurately reproducing the rich and intricate higher-order multiple wave fields observed experimentally in the fluid-filled double string geometries.

Strengthening Methods for Assessing Students' Metahistorical Conceptions: Initial Development of the Historical Account Differences Survey

ERIC Educational Resources Information Center

O'Neill, D. Kevin; Guloy, Sheryl; Sensoy, Özlem

2014-01-01

To prepare students for participation in a pluralistic, democratic society, history curriculum should help them develop mature ideas about why multiple accounts of the same events exist. But how can we know if we are successful? In this article, we describe work on the design, validation, and piloting of a paper-and-pencil instrument called the…

Handbook Preparation as a Tool for Self-Directed Learning Process: A Case Study on Endocrine Topic

ERIC Educational Resources Information Center

Cerrah Ozsevgec, Lale; Ayas, Alipasa; Ozsevgec, Tuncay

2010-01-01

This study examines the effectiveness of handbook preparation as a method in the self-directed learning process of student teachers in teaching endocrine glands, and increasing their levels of knowledge. Thirty student teachers were selected from a biology department. A pencil and paper test and a clinical interview procedure were used to collect…

Person Fit Based on Statistical Process Control in an Adaptive Testing Environment. Research Report 98-13.

ERIC Educational Resources Information Center

van Krimpen-Stoop, Edith M. L. A.; Meijer, Rob R.

Person-fit research in the context of paper-and-pencil tests is reviewed, and some specific problems regarding person fit in the context of computerized adaptive testing (CAT) are discussed. Some new methods are proposed to investigate person fit in a CAT environment. These statistics are based on Statistical Process Control (SPC) theory. A…

CAT Procedures for Passage-Based Tests.

ERIC Educational Resources Information Center

Thompson, Tony D.; Davey, Tim

Methods to control the test construct and the efficiency of a computerized adaptive test (CAT) were studied in the context of a reading comprehension test given as a part of a battery of tests for college admission. A goal of the study was to create test scores that were interchangeable with those from a fixed form paper and pencil test. The first…

Use of a Mobile Application to Help Students Develop Skills Needed in Solving Force Equilibrium Problems

ERIC Educational Resources Information Center

Yang, Eunice

2016-01-01

This paper discusses the use of a free mobile engineering application (app) called Autodesk® ForceEffect™ to provide students assistance with spatial visualization of forces and more practice in solving/visualizing statics problems compared to the traditional pencil-and-paper method. ForceEffect analyzes static rigid-body systems using free-body…

A restricted signature normal form for Hermitian matrices, quasi-spectral decompositions, and applications

NASA Technical Reports Server (NTRS)

Freund, Roland W.; Huckle, Thomas

1989-01-01

In recent years, a number of results on the relationships between the inertias of Hermitian matrices and the inertias of their principal submatrices appeared in the literature. We study restricted congruence transformation of Hermitian matrices M which, at the same time, induce a congruence transformation of a given principal submatrix A of M. Such transformations lead to concept of the restricted signature normal form of M. In particular, by means of this normal form, we obtain short proofs of most of the known inertia theorems and also derive some new results of this type. For some applications, a special class of almost unitary restricted congruence transformations turns out to be useful. We show that, with such transformations, M can be reduced to a quasi-diagonal form which, in particular, displays the eigenvalues of A. Finally, applications of this quasi-spectral decomposition to generalize inverses and Hermitian matrix pencils are discussed.

X-ray luminescence computed tomography imaging based on X-ray distribution model and adaptively split Bregman method

PubMed Central

Chen, Dongmei; Zhu, Shouping; Cao, Xu; Zhao, Fengjun; Liang, Jimin

2015-01-01

X-ray luminescence computed tomography (XLCT) has become a promising imaging technology for biological application based on phosphor nanoparticles. There are mainly three kinds of XLCT imaging systems: pencil beam XLCT, narrow beam XLCT and cone beam XLCT. Narrow beam XLCT can be regarded as a balance between the pencil beam mode and the cone-beam mode in terms of imaging efficiency and image quality. The collimated X-ray beams are assumed to be parallel ones in the traditional narrow beam XLCT. However, we observe that the cone beam X-rays are collimated into X-ray beams with fan-shaped broadening instead of parallel ones in our prototype narrow beam XLCT. Hence we incorporate the distribution of the X-ray beams in the physical model and collected the optical data from only two perpendicular directions to further speed up the scanning time. Meanwhile we propose a depth related adaptive regularized split Bregman (DARSB) method in reconstruction. The simulation experiments show that the proposed physical model and method can achieve better results in the location error, dice coefficient, mean square error and the intensity error than the traditional split Bregman method and validate the feasibility of method. The phantom experiment can obtain the location error less than 1.1 mm and validate that the incorporation of fan-shaped X-ray beams in our model can achieve better results than the parallel X-rays. PMID:26203388

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klüter, Sebastian, E-mail: sebastian.klueter@med.uni-heidelberg.de; Schubert, Kai; Lissner, Steffen

Purpose: The dosimetric verification of treatment plans in helical tomotherapy usually is carried out via verification measurements. In this study, a method for independent dose calculation of tomotherapy treatment plans is presented, that uses a conventional treatment planning system with a pencil kernel dose calculation algorithm for generation of verification dose distributions based on patient CT data. Methods: A pencil beam algorithm that directly uses measured beam data was configured for dose calculation for a tomotherapy machine. Tomotherapy treatment plans were converted into a format readable by an in-house treatment planning system by assigning each projection to one static treatmentmore » field and shifting the calculation isocenter for each field in order to account for the couch movement. The modulation of the fluence for each projection is read out of the delivery sinogram, and with the kernel-based dose calculation, this information can directly be used for dose calculation without the need for decomposition of the sinogram. The sinogram values are only corrected for leaf output and leaf latency. Using the converted treatment plans, dose was recalculated with the independent treatment planning system. Multiple treatment plans ranging from simple static fields to real patient treatment plans were calculated using the new approach and either compared to actual measurements or the 3D dose distribution calculated by the tomotherapy treatment planning system. In addition, dose–volume histograms were calculated for the patient plans. Results: Except for minor deviations at the maximum field size, the pencil beam dose calculation for static beams agreed with measurements in a water tank within 2%/2 mm. A mean deviation to point dose measurements in the cheese phantom of 0.89% ± 0.81% was found for unmodulated helical plans. A mean voxel-based deviation of −0.67% ± 1.11% for all voxels in the respective high dose region (dose values >80%), and a mean local voxel-based deviation of −2.41% ± 0.75% for all voxels with dose values >20% were found for 11 modulated plans in the cheese phantom. Averaged over nine patient plans, the deviations amounted to −0.14% ± 1.97% (voxels >80%) and −0.95% ± 2.27% (>20%, local deviations). For a lung case, mean voxel-based deviations of more than 4% were found, while for all other patient plans, all mean voxel-based deviations were within ±2.4%. Conclusions: The presented method is suitable for independent dose calculation for helical tomotherapy within the known limitations of the pencil beam algorithm. It can serve as verification of the primary dose calculation and thereby reduce the need for time-consuming measurements. By using the patient anatomy and generating full 3D dose data, and combined with measurements of additional machine parameters, it can substantially contribute to overall patient safety.« less

Teaching the Factors Affecting Resistance Using Pencil Leads

ERIC Educational Resources Information Center

Küçüközer, Asuman

2015-01-01

The aim of this paper is to provide a way of teaching the factors that affect resistance using mechanical pencil leads and the brightness of the light given out by a light bulb connected to an electrical circuit. The resistance of a conductor is directly proportional to its length (L) and inversely proportional to its cross-sectional area (A).…

Computerized and Paper-and-Pencil Versions of the Rosenberg Self-Esteem Scale: A Comparison of Psychometric Features and Respondent Preferences.

ERIC Educational Resources Information Center

Vispoel, Walter P.; Boo, Jaeyool; Bleiler, Timothy

2001-01-01

Evaluated the characteristics of computerized and paper-and-pencil versions of the Rosenberg Self-Esteem Scale (SES) using scores for 224 college students. Results show that mode of administration has little effect on the psychometric properties of the SES although the computerized version took longer and was preferred by examinees. (SLD)

Pre-Service Teachers' Use of Different Types of Mathematical Reasoning in Paper-and-Pencil versus Technology-Supported Environments

ERIC Educational Resources Information Center

Zembat, Ismail Ozgur

2008-01-01

The current study compared the effects of technological environments with that of the paper-and-pencil environment on reasoning about the concept of derivatives in the context of maximum and minimum problems. The data consisted of clinical interviews conducted with three pre-service secondary mathematics teachers and a newly registered graduate…

Maternal Scaffolding of Preschoolers' Writing Using Tablet and Paper-Pencil Tasks: Relations with Emergent Literacy Skills

ERIC Educational Resources Information Center

Neumann, Michelle M.

2018-01-01

Mothers play a key role in scaffolding children's writing using traditional tools, such as paper and pencil. However, little is known about how mothers scaffold young children's writing using touch-screen tablets (e.g., iPads) and the associations between maternal scaffolding and emergent literacy. Mother-child dyads (N = 47; M child…

Use of Dynamic Geometry as a Support to Paper and Pencil Activities for Comprehension of Ratio and Proportion Topics

ERIC Educational Resources Information Center

Ruiz, Elena Fabiola; Lupianez, Jose Luis

2010-01-01

Introduction: The present paper shows the importance of a joint use of pencil and paper activities and of technology so that students may develop a complete understanding of ratio and proportion. A previous experience with strategy use when solving ratio and proportion problems provided background. Prompted by a recognition of the cognitive…

The Relationship of Laboratory Performance Ratings, Information Achievement and Pencil-Paper Performance Test Scores in College-Level Electricity.

ERIC Educational Resources Information Center

Francis, Charles E.

In this study, a pencil paper performance test (PPPT) was developed and administered to an experimental group of 46 students and a control group of 48 students to determine: (1) the difference between laboratory performance and the successful completion of a laboratory course in electricity, (2) the relationship between laboratory performance as…

Factor Structure and Validity of Paper-and-Pencil Measures of Mental Speed: Evidence for a Higher-Order Model?

ERIC Educational Resources Information Center

Danthiir, Vanessa; Wilhelm, Oliver; Schulze, Ralf; Roberts, Richard D.

2005-01-01

This study explored the structure of elementary cognitive tasks (ECTs) and relations between the corresponding construct(s) with processing speed (Gs) and fluid intelligence (Gf). Participants (N=321) completed 14 ECTs, 3 Gs, and 6 Gf marker tests, all administered in paper-and-pencil format to reduce potential confounds evident when tasks are…

Operator pencil passing through a given operator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biggs, A., E-mail: khudian@manchester.ac.uk, E-mail: adam.biggs@student.manchester.ac.uk; Khudaverdian, H. M., E-mail: khudian@manchester.ac.uk, E-mail: adam.biggs@student.manchester.ac.uk

Let Δ be a linear differential operator acting on the space of densities of a given weight λ{sub 0} on a manifold M. One can consider a pencil of operators Π-circumflex(Δ)=(Δ{sub λ}) passing through the operator Δ such that any Δ{sub λ} is a linear differential operator acting on densities of weight λ. This pencil can be identified with a linear differential operator Δ-circumflex acting on the algebra of densities of all weights. The existence of an invariant scalar product in the algebra of densities implies a natural decomposition of operators, i.e., pencils of self-adjoint and anti-self-adjoint operators. We studymore » lifting maps that are on one hand equivariant with respect to divergenceless vector fields, and, on the other hand, with values in self-adjoint or anti-self-adjoint operators. In particular, we analyze the relation between these two concepts, and apply it to the study of diff (M)-equivariant liftings. Finally, we briefly consider the case of liftings equivariant with respect to the algebra of projective transformations and describe all regular self-adjoint and anti-self-adjoint liftings. Our constructions can be considered as a generalisation of equivariant quantisation.« less

A new paper and pencil task reveals adult false belief reasoning bias.

PubMed

Coburn, Patricia I; Bernstein, Daniel M; Begeer, Sander

2015-09-01

Theory of mind (ToM) is the ability to take other people's perspective by inferring their mental state. Most 6-year olds pass the change-of-location false belief task that is commonly used to assess ToM. However, the change-of-location task is not suitable for individuals over 5 years of age, due to its discrete response options. In two experiments, we used a paper and pencil version of a modified change-of-location task (the Real Object Sandbox task) to assess false belief reasoning continuously rather than discretely in adults. Participants heard nine change-of-location scenarios and answered a critical question after each. The memory control questions only required the participant to remember the object's original location, whereas the false belief questions required participants to take the perspective of the protagonist. Participants were more accurate on memory trials than trials requiring perspective taking, and performance on paper and pencil trials correlated with corresponding trials on the Real Object Sandbox task. The Paper and Pencil Sandbox task is a convenient continuous measure of ToM that could be administered to a wide range of age groups.

Simulation for F.C.C. deformation texture by modified pencil glide theory[Face Centered Cubic

DOE Office of Scientific and Technical Information (OSTI.GOV)

Masui, H.

1999-11-26

Inspired by the pencil glide theory for b.c.c. metal, modified pencil glide theory for f.c.c. metal was proposed, dividing the 12 glide systems of f.c.c. metal into three groups individually composed of eight {l{underscore}brace}111{r{underscore}brace}{l{underscore}angle}110{r{underscore}angle} glide systems around the principal axes X[100], Y[010] and Z[001]. These assumptions yielded two mathematical solutions {Omega}(3) and {Omega}(1). In {Omega}(3), from the three groups with four complete conjugated glide systems composed of, respectively, two glide systems of common {l{underscore}angle}110{r{underscore}angle} direction, only one group with the maximum plastic work may operate if the requirements are satisfied, otherwise glide systems in {Omega}(1) where one of the fourmore » conjugated glide systems is zero are activated. The model considering the 12 glide systems of f.c.c. as a whole explained many experimentally stable orientations in axisymmetric and rolling deformation. The differences between the two pencil glide theories for b.c.c. and f.c.c. are also discussed with data.« less

The role of a microDiamond detector in the dosimetry of proton pencil beams.

PubMed

Gomà, Carles; Marinelli, Marco; Safai, Sairos; Verona-Rinati, Gianluca; Würfel, Jan

2016-03-01

In this work, the performance of a microDiamond detector in a scanned proton beam is studied and its potential role in the dosimetric characterization of proton pencil beams is assessed. The linearity of the detector response with the absorbed dose and the dependence on the dose-rate were tested. The depth-dose curve and the lateral dose profiles of a proton pencil beam were measured and compared to reference data. The feasibility of calibrating the beam monitor chamber with a microDiamond detector was also studied. It was found the detector reading is linear with the absorbed dose to water (down to few cGy) and the detector response is independent of both the dose-rate (up to few Gy/s) and the proton beam energy (within the whole clinically-relevant energy range). The detector showed a good performance in depth-dose curve and lateral dose profile measurements; and it might even be used to calibrate the beam monitor chambers-provided it is cross-calibrated against a reference ionization chamber. In conclusion, the microDiamond detector was proved capable of performing an accurate dosimetric characterization of proton pencil beams. Copyright © 2015. Published by Elsevier GmbH.

Writing forces associated with four pencil grasp patterns in grade 4 children.

PubMed

Schwellnus, Heidi; Carnahan, Heather; Kushki, Azadeh; Polatajko, Helene; Missiuna, Cheryl; Chau, Tom

2013-01-01

OBJECTIVE. We investigated differences in handwriting kinetics, speed, and legibility among four pencil grasps after a 10-min copy task. METHOD. Seventy-four Grade 4 students completed a handwriting assessment before and after a copy task. Grip and axial forces were measured with an instrumented stylus and force-sensitive tablet. We used multiple linear regression to analyze the relationship between grasp pattern and grip and axial forces. RESULTS. We found no kinetic differences among grasps, whether considered individually or grouped by the number of fingers on the barrel. However, when grasps were grouped according to the thumb position, the adducted grasps exhibited higher mean grip and axial forces. CONCLUSION. Grip forces were generally similar across the different grasps. Kinetic differences resulting from thumb position seemed to have no bearing on speed and legibility. Interventions for handwriting difficulties should focus more on speed and letter formation than on grasp pattern. Copyright © 2013 by the American Occupational Therapy Association, Inc.

Sensitive Adsorptive Voltammetric Method for Determination of Bisphenol A by Gold Nanoparticle/Polyvinylpyrrolidone-Modified Pencil Graphite Electrode

PubMed Central

Yaman, Yesim Tugce; Abaci, Serdar

2016-01-01

A novel electrochemical sensor gold nanoparticle (AuNP)/polyvinylpyrrolidone (PVP) modified pencil graphite electrode (PGE) was developed for the ultrasensitive determination of Bisphenol A (BPA). The gold nanoparticles were electrodeposited by constant potential electrolysis and PVP was attached by passive adsorption onto the electrode surface. The electrode surfaces were characterized by electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The parameters that affected the experimental conditions were researched and optimized. The AuNP/PVP/PGE sensor provided high sensitivity and selectivity for BPA recognition by using square wave adsorptive stripping voltammetry (SWAdSV). Under optimized conditions, the detection limit was found to be 1.0 nM. This new sensor system offered the advantages of simple fabrication which aided the expeditious replication, low cost, fast response, high sensitivity and low background current for BPA. This new sensor system was successfully tested for the detection of the amount of BPA in bottled drinking water with high reliability. PMID:27231912

New technology in dietary assessment: a review of digital methods in improving food record accuracy.

PubMed

Stumbo, Phyllis J

2013-02-01

Methods for conducting dietary assessment in the United States date back to the early twentieth century. Methods of assessment encompassed dietary records, written and spoken dietary recalls, FFQ using pencil and paper and more recently computer and internet applications. Emerging innovations involve camera and mobile telephone technology to capture food and meal images. This paper describes six projects sponsored by the United States National Institutes of Health that use digital methods to improve food records and two mobile phone applications using crowdsourcing. The techniques under development show promise for improving accuracy of food records.

Molecularly imprinted polymer-matrix nanocomposite for enantioselective electrochemical sensing of D- and L-aspartic acid.

PubMed

Prasad, Bhim Bali; Srivastava, Amrita; Tiwari, Mahavir Prasad

2013-10-01

A new molecularly imprinted polymer-matrix (titanium dioxide nanoparticle/multiwalled carbon nanotubes) nanocomposite was developed for the modification of pencil graphite electrode as an enantioselective sensing probe for aspartic acid isomers, prevalent at ultra trace level in aqueous and real samples. The nanocomposite having many shape complementary cavities was synthesized adopting surface initiated-activators regenerated by electron transfer for atom transfer radical polymerization. The proposed sensor has high stability, nanocomposite uniformity, good reproducibility, and enhanced electrocatalytic activity to respond oxidative peak current of L-aspartic acid quantitatively by differential pulse anodic stripping voltammetry, without any cross-reactivity in real samples. Under the optimized operating conditions, the L-aspartic acid imprinted modified electrode showed a wide linear response for L-aspartic acid within the concentration range 9.98-532.72 ng mL(-1), with the minimum detection limit of 1.73-1.79 ng mL(-1) (S/N=3) in aqueous and real samples. Almost similar stringent limit (1.79 ng mL(-1)) was obtained with cerebrospinal fluid which is typical for the primitive diagnosis of neurological disorders, caused by an acute depletion of L-aspartic acid biomarker, in clinical settings. Copyright © 2013 Elsevier B.V. All rights reserved.

A comparison of TPS and different measurement techniques in small-field electron beams.

PubMed

Donmez Kesen, Nazmiye; Cakir, Aydin; Okutan, Murat; Bilge, Hatice

2015-01-01

In recent years, small-field electron beams have been used for the treatment of superficial lesions, which requires small circular fields. However, when using very small electron fields, some significant dosimetric problems may occur. In this study, dose distributions and outputs of circular fields with dimensions of 5cm and smaller, for nominal energies of 6, 9, and 15MeV from the Siemens ONCOR Linac, were measured and compared with data from a treatment planning system using the pencil-beam algorithm in electron beam calculations. All dose distribution measurements were performed using the Gafchromic EBT film; these measurements were compared with data that were obtained from the Computerized Medical Systems (CMS) XiO treatment planning system (TPS), using the gamma-index method in the PTW VeriSoft software program. Output measurements were performed using the Gafchromic EBT film, an Advanced Markus ion chamber, and thermoluminescent dosimetry (TLD). Although the pencil-beam algorithm is used to model electron beams in many clinics, there is no substantial amount of detailed information in the literature about its use. As the field size decreased, the point of maximum dose moved closer to the surface. Output factors were consistent; differences from the values obtained from the TPS were, at maximum, 42% for 6 and 15MeV and 32% for 9MeV. When the dose distributions from the TPS were compared with the measurements from the Gafchromic EBT films, it was observed that the results were consistent for 2-cm diameter and larger fields, but the outputs for fields of 1-cm diameter and smaller were not consistent. In CMS XiO TPS, calculated using the pencil-beam algorithm, the dose distributions of electron treatment fields that were created with circular cutout of a 1-cm diameter were not appropriate for patient treatment and the pencil-beam algorithm is not convenient for monitor unit (MU) calculations in electron dosimetry. Copyright © 2015 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

A Comparison of Item Selection Procedures Using Different Ability Estimation Methods in Computerized Adaptive Testing Based on the Generalized Partial Credit Model

ERIC Educational Resources Information Center

Ho, Tsung-Han

2010-01-01

Computerized adaptive testing (CAT) provides a highly efficient alternative to the paper-and-pencil test. By selecting items that match examinees' ability levels, CAT not only can shorten test length and administration time but it can also increase measurement precision and reduce measurement error. In CAT, maximum information (MI) is the most…

SU-E-T-567: Neutron Dose Equivalent Evaluation for Pencil Beam Scanning Proton Therapy with Apertures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geng, C; Nanjing University of Aeronautics and Astronautics, Nanjing; Schuemann, J

Purpose: To determine the neutron contamination from the aperture in pencil beam scanning during proton therapy. Methods: A Monte Carlo based proton therapy research platform TOPAS and the UF-series hybrid pediatric phantoms were used to perform this study. First, pencil beam scanning (PBS) treatment pediatric plans with average spot size of 10 mm at iso-center were created and optimized for three patients with and without apertures. Then, the plans were imported into TOPAS. A scripting method was developed to automatically replace the patient CT with a whole body phantom positioned according to the original plan iso-center. The neutron dose equivalentmore » was calculated using organ specific quality factors for two phantoms resembling a 4- and 14-years old patient. Results: The neutron dose equivalent generated by the apertures in PBS is 4–10% of the total neutron dose equivalent for organs near the target, while roughly 40% for organs far from the target. Compared to the neutron dose equivalent caused by PBS without aperture, the results show that the neutron dose equivalent with aperture is reduced in the organs near the target, and moderately increased for those organs located further from the target. This is due to the reduction of the proton dose around the edge of the CTV, which causes fewer neutrons generated in the patient. Conclusion: Clinically, for pediatric patients, one might consider adding an aperture to get a more conformal treatment plan if the spot size is too large. This work shows the somewhat surprising fact that adding an aperture for beam scanning for facilities with large spot sizes reduces instead of increases a potential neutron background in regions near target. Changran Geng is supported by the Chinese Scholarship Council (CSC) and the National Natural Science Foundation of China (Grant No. 11475087)« less

Cross-Mode Comparability of Computer-Based Testing (CBT) versus Paper-Pencil Based Testing (PPT): An Investigation of Testing Administration Mode among Iranian Intermediate EFL Learners

ERIC Educational Resources Information Center

Khoshsima, Hooshang; Hosseini, Monirosadat; Toroujeni, Seyyed Morteza Hashemi

2017-01-01

Advent of technology has caused growing interest in using computers to convert conventional paper and pencil-based testing (Henceforth PPT) into Computer-based testing (Henceforth CBT) in the field of education during last decades. This constant promulgation of computers to reshape the conventional tests into computerized format permeated the…

The Co-Emergence of Machine Techniques, Paper-and-Pencil Techniques, and Theoretical Reflection: A Study of CAS Use in Secondary School Algebra

ERIC Educational Resources Information Center

Kieran, Carolyn; Drijvers, Paul

2006-01-01

This paper addresses the dialectical relation between theoretical thinking and technique, as they co-emerge in a combined computer algebra (CAS) and paper-and-pencil environment. The theoretical framework in this ongoing study consists of the instrumental approach to tool use and an adaptation of Chevallard's anthropological theory. The main aim…

The Development and Empowerment of Mathematical Abilities: The Impact of Pencil and Paper and Computerised Interventions for Preschool Children

ERIC Educational Resources Information Center

Mascia, Maria Lidia; Agus, Mirian; Fastame, Maria Chiara; Penna, Maria Pietronilla; Sale, Eliana; Pessa, Eliano

2015-01-01

The development of numerical abilities was examined in three groups of 5 year-olds: one including 13 children accomplishing a numerical training in pencil-and-paper format (EG1); another group including 21 children accomplished a homologous training in computerized format; the remaining 24 children were assigned to the control group (CG). The…

Evaluating the Comparability of Paper-and-Pencil and Computerized Versions of a Large-Scale Certification Test. Research Report. ETS RR-05-21

ERIC Educational Resources Information Center

Puhan, Gautam; Boughton, Keith A.; Kim, Sooyeon

2005-01-01

The study evaluated the comparability of two versions of a teacher certification test: a paper-and-pencil test (PPT) and computer-based test (CBT). Standardized mean difference (SMD) and differential item functioning (DIF) analyses were used as measures of comparability at the test and item levels, respectively. Results indicated that effect sizes…

Inventory of Motive of Preference for Conventional Paper-and-Pencil Tests: A Study of Validity and Reliability

ERIC Educational Resources Information Center

Eser, Mehmet Taha; Dogan, Nuri

2017-01-01

Purpose: The objective of this study is to develop the Inventory of Motive of Preference for Conventional Paper-And-Pencil Tests and to evaluate students' motives for preferring written tests, short-answer tests, true/false tests or multiple-choice tests. This will add a measurement tool to the literature with valid and reliable results to help…

Alternative Modes of Measuring Self-Reports on HIV-Related Behaviors among College Students: Web-Delivered Mode versus Paper-Pencil Mode

ERIC Educational Resources Information Center

Hou, Su-I

2007-01-01

HIV-related behaviors, self-reported using Web-delivered or paper-pencil modes, were collected from two convenience samples of college students at a major university in the southeastern U.S. To enhance the equivalence of the comparisons, a subset pool of participants from each group, proportionally matched on key demographic variables including…

SU-E-T-91: Accuracy of Dose Calculation Algorithms for Patients Undergoing Stereotactic Ablative Radiotherapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tajaldeen, A; Ramachandran, P; Geso, M

2015-06-15

Purpose: The purpose of this study was to investigate and quantify the variation in dose distributions in small field lung cancer radiotherapy using seven different dose calculation algorithms. Methods: The study was performed in 21 lung cancer patients who underwent Stereotactic Ablative Body Radiotherapy (SABR). Two different methods (i) Same dose coverage to the target volume (named as same dose method) (ii) Same monitor units in all algorithms (named as same monitor units) were used for studying the performance of seven different dose calculation algorithms in XiO and Eclipse treatment planning systems. The seven dose calculation algorithms include Superposition, Fastmore » superposition, Fast Fourier Transform ( FFT) Convolution, Clarkson, Anisotropic Analytic Algorithm (AAA), Acurous XB and pencil beam (PB) algorithms. Prior to this, a phantom study was performed to assess the accuracy of these algorithms. Superposition algorithm was used as a reference algorithm in this study. The treatment plans were compared using different dosimetric parameters including conformity, heterogeneity and dose fall off index. In addition to this, the dose to critical structures like lungs, heart, oesophagus and spinal cord were also studied. Statistical analysis was performed using Prism software. Results: The mean±stdev with conformity index for Superposition, Fast superposition, Clarkson and FFT convolution algorithms were 1.29±0.13, 1.31±0.16, 2.2±0.7 and 2.17±0.59 respectively whereas for AAA, pencil beam and Acurous XB were 1.4±0.27, 1.66±0.27 and 1.35±0.24 respectively. Conclusion: Our study showed significant variations among the seven different algorithms. Superposition and AcurosXB algorithms showed similar values for most of the dosimetric parameters. Clarkson, FFT convolution and pencil beam algorithms showed large differences as compared to superposition algorithms. Based on our study, we recommend Superposition and AcurosXB algorithms as the first choice of algorithms in lung cancer radiotherapy involving small fields. However, further investigation by Monte Carlo simulation is required to confirm our results.« less

Paper and pencil vs online self-administered food frequency questionnaire (FFQ) applied to university population: a pilot study.

PubMed

González Carrascosa, R; García Segovia, P; Martínez Monzó, J

2011-01-01

To test the reliability of dietary intake data measured with an online food frequency questionnaires (FFQ) applied to a university population by comparing the results with those from a paper and pencil version. A total of 50 students were recruited from the second-year Food Technology course at the Universitat Politècnica de València (Comunidad Valenciana, Spain) in the academic year 2008-2009. The students were between the ages of 20-32. The participants completed both presentation modes of the FFQ (paper and pencil and online) in a cross-over study with a time interval of 3-week. To study the effect of ordering of the questionnaires, participants were randomly assigned to group A (paper and pencil FFQ first) and group B (online FFQ first). Both self-administered semi-quantitative presentations of the FFQ included 84 food items divided into six groups (dairy products; eggs, meat and fish; vegetables, legumes and fruits; bread, cereals and similar; oils, fats and sweets; beverages and pre-cooked). Participants were asked how frequently and how much each food item they had consumed in the previous year. The response rate was 78% (39 students, 23% men and 77% women). For the total sample, the median dietary intakes were higher for the paper and pencil FFQ than the online version for energy (2,077 vs. 1,635 kcal/day), proteins (96 vs. 88 g/day), carbohydrates (272 vs. 211 g/day), and fat (70 vs. 58 g/day), respectively. These differences were statistically significant. However, there were not significant differences between the two presentations when the consumption by groups of food was calculated, except for "beverages and pre-cooked" group. The pilot testing showed that this online FFQ is a useful tool for estimating the intake of food groups in this university population. On the other hand, the differences found in the results of the absolute quantities of energy and nutrients intakes were not clear. These differences could be due to the problems that the participants had for reporting portion size in the paper and pencil FFQ as photographs of portion sizes were not presented.

Experimental demonstration of a trophic cascade in the Galápagos rocky subtidal: Effects of consumer identity and behavior.

PubMed

Witman, Jon D; Smith, Franz; Novak, Mark

2017-01-01

In diverse tropical webs, trophic cascades are presumed to be rare, as species interactions may dampen top-down control and reduce their prevalence. To test this hypothesis, we used an open experimental design in the Galápagos rocky subtidal that enabled a diverse guild of fish species, in the presence of each other and top predators (sea lions and sharks), to attack two species of sea urchins grazing on benthic algae. Time-lapse photography of experiments on natural and experimental substrates revealed strong species identity effects: only two predator species-blunthead triggerfish (Pseudobalistes naufragium) and finescale triggerfish (Balistes polylepis)-drove a diurnal trophic cascade extending to algae, and they preferred large pencil urchins (Eucidaris galapagensis) over green urchins (Lytechinus semituberculatus). Triggerfish predation effects were strong, causing a 24-fold reduction of pencil urchin densities during the initial 21 hours of a trophic cascade experiment. A trophic cascade was demonstrated for pencil urchins, but not for green urchins, by significantly higher percent cover of urchin-grazed algae in cages that excluded predatory fish than in predator access (fence) treatments. Pencil urchins were more abundant at night when triggerfish were absent, suggesting that this species persists by exploiting a nocturnal predation refuge. Time-series of pencil urchin survivorship further demonstrated per capita interference effects of hogfish and top predators. These interference effects respectively weakened and extended the trophic cascade to a fourth trophic level through behavioral modifications of the triggerfish-urchin interaction. We conclude that interference behaviors capable of modifying interaction strength warrant greater attention as mechanisms for altering top-down control, particularly in speciose food webs.

Experimental demonstration of a trophic cascade in the Galápagos rocky subtidal: Effects of consumer identity and behavior

PubMed Central

Witman, Jon D.; Smith, Franz; Novak, Mark

2017-01-01

In diverse tropical webs, trophic cascades are presumed to be rare, as species interactions may dampen top-down control and reduce their prevalence. To test this hypothesis, we used an open experimental design in the Galápagos rocky subtidal that enabled a diverse guild of fish species, in the presence of each other and top predators (sea lions and sharks), to attack two species of sea urchins grazing on benthic algae. Time-lapse photography of experiments on natural and experimental substrates revealed strong species identity effects: only two predator species–blunthead triggerfish (Pseudobalistes naufragium) and finescale triggerfish (Balistes polylepis)–drove a diurnal trophic cascade extending to algae, and they preferred large pencil urchins (Eucidaris galapagensis) over green urchins (Lytechinus semituberculatus). Triggerfish predation effects were strong, causing a 24-fold reduction of pencil urchin densities during the initial 21 hours of a trophic cascade experiment. A trophic cascade was demonstrated for pencil urchins, but not for green urchins, by significantly higher percent cover of urchin-grazed algae in cages that excluded predatory fish than in predator access (fence) treatments. Pencil urchins were more abundant at night when triggerfish were absent, suggesting that this species persists by exploiting a nocturnal predation refuge. Time-series of pencil urchin survivorship further demonstrated per capita interference effects of hogfish and top predators. These interference effects respectively weakened and extended the trophic cascade to a fourth trophic level through behavioral modifications of the triggerfish-urchin interaction. We conclude that interference behaviors capable of modifying interaction strength warrant greater attention as mechanisms for altering top-down control, particularly in speciose food webs. PMID:28430794

Operating room fire prevention: creating an electrosurgical unit fire safety device.

PubMed

Culp, William C; Kimbrough, Bradly A; Luna, Sarah; Maguddayao, Aris J

2014-08-01

To reduce the incidence of surgical fires. Operating room fires represent a potentially life-threatening hazard and are triggered by the electrosurgical unit (ESU) pencil. Carbon dioxide is a fire suppressant and is a routinely used medical gas. We hypothesize that a shroud of protective carbon dioxide covering the tip of the ESU pencil displaces oxygen, thereby preventing fire ignition. Using 3-dimensional modeling techniques, a polymer sleeve was created and attached to an ESU pencil. This sleeve was connected to a carbon dioxide source and directed the gas through multiple precisely angled ports, generating a cone of fire-suppressive carbon dioxide surrounding the active pencil tip. This device was evaluated in a flammability test chamber containing 21%, 50%, and 100% oxygen with sustained ESU activation. The sleeve was tested with and without carbon dioxide (control) until a fuel was ignited or 30 seconds elapsed. Time to ignition was measured by high-speed videography. Fires were ignited with each control trial (15/15 trials). The control group median ± SD ignition time in 21% oxygen was 3.0 ± 2.4 seconds, in 50% oxygen was 0.1 ± 1.8 seconds, and in 100% oxygen was 0.03 ± 0.1 seconds. No fire was observed when the fire safety device was used in all concentrations of oxygen (0/15 trials; P < 0.0001). The exact 95% confidence interval for absolute risk reduction of fire ignition was 76% to 100%. A sleeve creating a cone of protective carbon dioxide gas enshrouding the sparks from an ESU pencil effectively prevents fire in a high-flammability model. Clinical application of this device may reduce the incidence of operating room fires.

Origin of Outer Solar System

NASA Technical Reports Server (NTRS)

Holman, Matthew J.; Boyce, J. (Technical Monitor)

2003-01-01

We feel that at the present moment the available theoretical models of the Kuiper belt are still in advance of the data, and thus our main task has been to conduct observational work guided by theoretical motivations. Our efforts over the past year can be divided into four categories: A) Wide-field Searches for Kuiper Belt Objects; B) Pencil-beam Searches for Kuiper Belt Objects; C) Wide-field Searches for Moons of the Outer Planets; D) Pencil-beam Searches for Faint Uranian and Neptunian Moons; E) Recovery Observations. As of April 2002, we have conducted several searches for Kuiper belt objects using large-format mosaic CCD camera on 4-meter class telescopes. In May 1999, we used the Kitt Peak 4-meter with the NOAO Mosaic camera we attempted a search for KBOs at a range of ecliptic latitudes. In addition to our wide-field searches, we have conducted three 'pencil-beam' searches in the past year. In a pencil-beam search we take repeated integrations of the same field throughout a night. After preprocessing the resulting images we shift and recombine them along a range of rates and directions consistent with the motion of KBOs. Stationary objects then smear out, while objects moving at near the shift rate appear as point sources. In addition to our searches for Kuiper belt objects, we are completing the inventory of the outer solar system by search for faint satellites of the outer planets. In August 2001 we conducted pencil beam searches for faint Uranian and Neptunian satellites at CFHT and CTIO. These searches resulted in the discover of two Neptunian and four Uranian satellite candidates. The discovery of Kuiper belt objects and outer planet satellites is of little use if the discoveries are not followed by systematic, repeated astrometric observations that permit reliable estimates of their orbits.

Measurement agreement of the self-administered questionnaire of the Belgian Health Interview Survey: Paper-and-pencil versus web-based mode.

PubMed

Braekman, Elise; Berete, Finaba; Charafeddine, Rana; Demarest, Stefaan; Drieskens, Sabine; Gisle, Lydia; Molenberghs, Geert; Tafforeau, Jean; Van der Heyden, Johan; Van Hal, Guido

2018-01-01

Before organizing mixed-mode data collection for the self-administered questionnaire of the Belgian Health Interview Survey, measurement effects between the paper-and-pencil and the web-based questionnaire were evaluated. A two-period cross-over study was organized with a sample of 149 employees of two Belgian research institutes (age range 22-62 years, 72% female). Measurement agreement was assessed for a diverse range of health indicators related to general health, mental and psychosocial health, health behaviors and prevention with kappa coefficients and intraclass correlation (ICC). The quality of the data collected by both modes was evaluated by quantifying the missing, 'don't know' and inconsistent values and data entry mistakes. Good to very good agreement was found for all categorical indicators with kappa coefficients superior to 0.60, except for two mental and psychosocial health indicators namely the presence of a sleeping disorder and of a depressive disorder (kappa≥0.50). For the continuous indicators high to acceptable agreement was observed with ICC superior to 0.70. Inconsistent answers and data-entry mistakes were only occurring in the paper-and-pencil mode. There were no less missing values in the web-based mode compared to the paper-and-pencil mode. The study supports the idea that web-based modes provide, in general, equal responses to paper-and-pencil modes. However, health indicators based upon factual and objective items tend to have higher measurement agreement than indicators requiring an assessment of personal subjective feelings. A web-based mode greatly facilitates the data-entry process and guides the completing of a questionnaire. However, item non-response was not positively affected.

Surface amplification of pencil graphite electrode with polypyrrole and reduced graphene oxide for fabrication of a guanine/adenine DNA based electrochemical biosensors for determination of didanosine anticancer drug

NASA Astrophysics Data System (ADS)

Karimi-Maleh, Hassan; Bananezhad, Asma; Ganjali, Mohammad R.; Norouzi, Parviz; Sadrnia, Abdolhossein

2018-05-01

Didanosine is nucleoside analog reverse transcriptase inhibitors with many side effects such as nausea and vomiting, stomach pain, tingling, burning and numbness and determination of this drug is very important in biological samples. This paper presents a DNA biosensor for determination of didanosine (DDI) in pharmaceutical samples. A pencil graphite electrode modified with conductive materials such as polypyrrole (PPy) and reduced graphene oxide (rGO) (PGE/PPy/rGO) was used for this goal. The double-stranded DNA was successfully immobilized on PGE/PPy/rGO. The PGE/PPy/rGO was characterized by microscopic and electrochemical methods. Then, the interaction of DDI with DNA was identified by decreases in the oxidation currents of guanine and adenine by differential pulse voltammetric (DPV) method. The dynamic range of DDI identified in the range of 0.02-50.0 μM and this electrode provided a low limit of detection (LOD = 8.0 nM) for DDI. The PGE/PPy/rGO loaded with ds-DNA was utilized for the measurement of DDI in real samples and obtained data were compared with HPLC method. The statistical tests such as F-test and t-test were used for confirming ability of PGE/PPy/rGO loaded with ds-DNA for analysis of DDI in real samples.

Supine craniospinal irradiation in pediatric patients by proton pencil beam scanning.

PubMed

Farace, Paolo; Bizzocchi, Nicola; Righetto, Roberto; Fellin, Francesco; Fracchiolla, Francesco; Lorentini, Stefano; Widesott, Lamberto; Algranati, Carlo; Rombi, Barbara; Vennarini, Sabina; Amichetti, Maurizio; Schwarz, Marco

2017-04-01

Proton therapy is the emerging treatment modality for craniospinal irradiation (CSI) in pediatric patients. Herein, special methods adopted for CSI at proton Therapy Center of Trento by pencil beam scanning (PBS) are comprehensively described. Twelve pediatric patients were treated by proton PBS using two/three isocenters. Special methods refer to: (i) patient positioning in supine position on immobilization devices crossed by the beams; (ii) planning field-junctions via the ancillary-beam technique; (iii) achieving lens-sparing by three-beams whole-brain-irradiation; (iv) applying a movable-snout and beam-splitting technique to reduce the lateral penumbra. Patient-specific quality assurance (QA) program was performed using two-dimensional ion chamber array and γ-analysis. Daily kilovoltage alignment was performed. PBS allowed to obtain optimal target coverage (mean D98%>98%) with reduced dose to organs-at-risk. Lens sparing was obtained (mean D1∼730cGyE). Reducing lateral penumbra decreased the dose to the kidneys (mean Dmean<600cGyE). After kilovoltage alignment, potential dose deviations in the upper and lower junctions were small (average 0.8% and 1.2% respectively). Due to imperfect modeling of range shifter, QA showed better agreements between measurements and calculations at depths >4cm (mean γ>95%) than at depths<4cm. The reported methods allowed to effectively perform proton PBS CSI. Copyright © 2017 Elsevier B.V. All rights reserved.

Does computerizing paper-and-pencil job attitude scales make a difference? New IRT analyses offer insight.

PubMed

Donovan, M A; Drasgow, F; Probst, T M

2000-04-01

The measurement equivalence of 2 scales of the Job Descriptive Index (JDI; P. C. Smith, L. M. Kendall, & C. L. Hulin, 1969), the Supervisor Satisfaction scale and the Coworker Satisfaction scale, was examined across computerized and paper-and-pencil administrations. In this study, employees in 2 organizations (N = 1,777) were administered paper-and-pencil versions of the scales, and employees in a third organization (N = 509) were administered a computerized version. A newly developed item response theory (IRT) technique for examining differential test functioning (N. S. Raju, W. J. van der Linden, & P. F. Fleer, 1995) was used to examine measurement equivalence across media. Results support the measurement equivalence of the JDI Supervisor and Coworker scales across administration media. The implications of these findings for both practitioners and organizational researchers are discussed.

Children's Attributional Style from Middle Childhood to Early Adolescence: Further Validation of the Paper-and-Pencil Versions of the Children's Attributional Style Interview

ERIC Educational Resources Information Center

Rueger, Sandra Yu; Haines, Beth A.; Malecki, Christine Kerres

2010-01-01

The psychometric properties of two paper-and-pencil versions of the Children's Attributional Style Interview (i.e., CASI-I and CASI-II) were evaluated in a sample of 166 third and fourth graders and a sample of 245 sixth and seventh graders. The results demonstrated strong internal consistency reliability, convergent validity, and a factor…

Paper-and-Pencil and Web-Based Testing: The Measurement Invariance of the Big Five Personality Tests in Applied Settings

ERIC Educational Resources Information Center

Vecchione, Michele; Alessandri, Guido; Barbaranelli, Claudio

2012-01-01

This study investigates the measurement equivalence of a five-factor measure of personality across two groups applying for jobs, who completed the same questionnaire using either a paper-and-pencil (n = 429) or a web online answer format (n = 651). The data were collected using the Big Five Questionnaire-2 (BFQ-2; which is a measure of the Five…

High School Students' Forming 3D Objects Using Technological and Non-Technological Tools

ERIC Educational Resources Information Center

Okumus, Samet; Hollebrands, Karen

2016-01-01

We analyzed the ways in which two high school students formed 3D objects from the rotation of 2D figures. The students participated in a task-based interview using paper-and-pencil, manipulatives, and Cabri 3D. The results indicated that they had difficulty using paper-and-pencil to rotate 2D figures to form 3D objects. Their difficulty stemmed…

Flexible Execution of Cognitive Procedures.

DTIC Science & Technology

1987-06-30

were drawn from three third-grade classrooms The classrooms were pre-tested twice using a paper-and-pencil diagnostic test. We selected 33 students...tested individually in a small room adjacent to their classroom . Each student solved an individualized paper-and-pencil test whose items were designed... tablet , and students filled out the test with a special pen. Equipment malfunctions caused the data from 7 students to be lost. Tablet data from each of

Development of a Novel, Low-Cost, Disposable Wooden Pencil Graphite Electrode for Use in the Determination of Antioxidants and Other Biological Compounds.

PubMed

Kariuki, James; Ervin, Emily; Olafson, Carly

2015-07-31

The development of portable sensors that can be used outside the lab is an active area of research in the electroanalytical field. A major focus of such research is the development of low-cost electrodes for use in these sensors. Current electrodes, such as glassy-carbon electrodes (GCEs), are costly and require time-consuming preparation. Alternatives have been proposed, including mechanical pencil-lead electrodes (MPEs). However, MPEs themselves possess numerous drawbacks, particularly structural fragility. In this paper, we present a novel pencil-graphite electrode (PGE) fabricated from a regular HB#2 pencil. This PGE is a simple, disposable, extremely low-cost alternative to GCEs ($0.30 per PGE, vs. $190 + per GCE), and possesses the structural stability that MPEs lack. PGEs were characterized by square-wave voltammetry of ferricyanide, gallic acid, uric acid, dopamine, and several foodstuffs. In all cases, PGEs demonstrated sensitivities comparable or superior to those of the GCE and MPE (LOD = 5.62 × 10(-4) M PGE, 4.80 × 10(-4) M GCE, 2.93 × 10(-4) M MPE). Signal areas and peak heights were typically four to ten times larger for the PGE relative to the GCE.

Is the Male Advantage in Mental-Rotation Performance Task Independent? On the Usability of Chronometric Tests and Paper-and-Pencil Tests in Children

ERIC Educational Resources Information Center

Quaiser-Pohl, Claudia; Neuburger, Sarah; Heil, Martin; Jansen, Petra; Schmelter, Andrea

2014-01-01

This article presents a reanalysis of the data of 862 second and fourth graders collected in two previous studies, focusing on the influence of method (psychometric vs. chronometric) and stimulus type on the gender difference in mental-rotation accuracy. The children had to solve mental-rotation tasks with animal pictures, letters, or cube…

Technical Note: Dose gradients and prescription isodose in orthovoltage stereotactic radiosurgery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fagerstrom, Jessica M., E-mail: fagerstrom@wisc.edu; Bender, Edward T.; Culberson, Wesley S.

Purpose: The purpose of this work is to examine the trade-off between prescription isodose and dose gradients in orthovoltage stereotactic radiosurgery. Methods: Point energy deposition kernels (EDKs) describing photon and electron transport were calculated using Monte Carlo methods. EDKs were generated from 10  to 250 keV, in 10 keV increments. The EDKs were converted to pencil beam kernels and used to calculate dose profiles through isocenter from a 4π isotropic delivery from all angles of circularly collimated beams. Monoenergetic beams and an orthovoltage polyenergetic spectrum were analyzed. The dose gradient index (DGI) is the ratio of the 50% prescription isodosemore » volume to the 100% prescription isodose volume and represents a metric by which dose gradients in stereotactic radiosurgery (SRS) may be evaluated. Results: Using the 4π dose profiles calculated using pencil beam kernels, the relationship between DGI and prescription isodose was examined for circular cones ranging from 4 to 18 mm in diameter and monoenergetic photon beams with energies ranging from 20 to 250 keV. Values were found to exist for prescription isodose that optimize DGI. Conclusions: The relationship between DGI and prescription isodose was found to be dependent on both field size and energy. Examining this trade-off is an important consideration for designing optimal SRS systems.« less

Effect of inhomogeneity in a patient's body on the accuracy of the pencil beam algorithm in comparison to Monte Carlo

NASA Astrophysics Data System (ADS)

Yamashita, T.; Akagi, T.; Aso, T.; Kimura, A.; Sasaki, T.

2012-11-01

The pencil beam algorithm (PBA) is reasonably accurate and fast. It is, therefore, the primary method used in routine clinical treatment planning for proton radiotherapy; still, it needs to be validated for use in highly inhomogeneous regions. In our investigation of the effect of patient inhomogeneity, PBA was compared with Monte Carlo (MC). A software framework was developed for the MC simulation of radiotherapy based on Geant4. Anatomical sites selected for the comparison were the head/neck, liver, lung and pelvis region. The dose distributions calculated by the two methods in selected examples were compared, as well as a dose volume histogram (DVH) derived from the dose distributions. The comparison of the off-center ratio (OCR) at the iso-center showed good agreement between the PBA and MC, while discrepancies were seen around the distal fall-off regions. While MC showed a fine structure on the OCR in the distal fall-off region, the PBA showed smoother distribution. The fine structures in MC calculation appeared downstream of very low-density regions. Comparison of DVHs showed that most of the target volumes were similarly covered, while some OARs located around the distal region received a higher dose when calculated by MC than the PBA.

Implementation of a Computerized Tablet-Survey in an Adolescent Large-Scale, School-Based Study.

PubMed

Delk, Joanne; Harrell, Melissa B; Fakhouri, Tala H I; Muir, Katelyn A; Perry, Cheryl L

2017-07-01

Computerized surveys present many advantages over paper surveys. However, school-based adolescent research questionnaires still mainly rely on paper-and-pencil surveys as access to computers in schools is often not practical. Tablet-assisted self-interviews (TASI) present a possible solution, but their use is largely untested. This paper presents a method for and our experiences with implementing a TASI in a school setting. A TASI was administered to 3907 middle and high school students from 79 schools. The survey assessed use of tobacco products and exposure to tobacco marketing. To assess in-depth tobacco use behaviors, the TASI employed extensive skip patterns to reduce the number of not-applicable questions that nontobacco users received. Pictures were added to help respondents identify the tobacco products they were being queried about. Students were receptive to the tablets and required no instructions in their use. None were lost, stolen, or broken. Item nonresponse, unanswered questions, was a pre-administration concern; however, 92% of participants answered 96% or more of the questions. This method was feasible and successful among a diverse population of students and schools. It generated a unique dataset of in-depth tobacco use behaviors that would not have been possible through a paper-and-pencil survey. © 2017, American School Health Association.

The Comparison of Accuracy Scores on the Paper and Pencil Testing vs. Computer-Based Testing

ERIC Educational Resources Information Center

Retnawati, Heri

2015-01-01

This study aimed to compare the accuracy of the test scores as results of Test of English Proficiency (TOEP) based on paper and pencil test (PPT) versus computer-based test (CBT). Using the participants' responses to the PPT documented from 2008-2010 and data of CBT TOEP documented in 2013-2014 on the sets of 1A, 2A, and 3A for the Listening and…

Pencil Beam Scanning Proton Therapy for Rhabdomyosarcoma of the Biliary Tract.

PubMed

Pater, Luke; Turpin, Brian; Mascia, Anthony

2017-10-05

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma of childhood with 250-350 cases diagnosed annually in the United States. Biliary tract rhabdomyosarcoma is rare, representing <1% of the RMS cases. Due to its location, resection is clinically challenging, and functional complications exist and persist from biliary obstruction. The anatomical location of this tumor presents both opportunities and challenges for pencil beam scanning proton therapy. Proton therapy offers a dosimetric and clinical advantage by sparing the healthy liver, stomach, contra-lateral kidney and bowel. Motion management and anatomical variations, such as intestinal filling or weight loss, requiring routine dosimetric evaluation and possible adaptive treatment planning, present challenges for the use of proton therapy. By taking advantage of the superior dose distribution of proton radiation, assessing the impact of tumor and anatomy motion, and performing regular dose evaluations, biliary tract RMS is an ideal diagnosis for pencil beam scanning proton therapy.

Hand Strength, Handwriting, and Functional Skills in Children With Autism.

PubMed

Alaniz, Michele L; Galit, Eleanor; Necesito, Corina Isabel; Rosario, Emily R

2015-01-01

To establish hand strength development trends in children with autism and to investigate correlations between grip and pinch strength, components of handwriting, and functional activities in children with and without autism. Fifty-one children were divided into two groups: typically developing children and children on the autism spectrum. Each child completed testing for pinch and grip strength, handwriting legibility, pencil control, and independence in functional activities. The children with autism followed the same strength development trends as the typically developing children. Grip strength correlated with pencil control in both groups and with handwriting legibility in the typically developing children but not in the children with autism. Grip and pinch strength correlated with independence with functional activities in both groups. This study provides evidence that grip and pinch strength are important components in developing pencil control, handwriting legibility, and independence with functional fine motor tasks. Copyright © 2015 by the American Occupational Therapy Association, Inc.

Scanning wind-vector scatterometers with two pencil beams

NASA Technical Reports Server (NTRS)

Kirimoto, T.; Moore, R. K.

1984-01-01

A scanning pencil-beam scatterometer for ocean windvector determination has potential advantages over the fan-beam systems used and proposed heretofore. The pencil beam permits use of lower transmitter power, and at the same time allows concurrent use of the reflector by a radiometer to correct for atmospheric attenuation and other radiometers for other purposes. The use of dual beams based on the same scanning reflector permits four looks at each cell on the surface, thereby improving accuracy and allowing alias removal. Simulation results for a spaceborne dual-beam scanning scatterometer with a 1-watt radiated power at an orbital altitude of 900 km is described. Two novel algorithms for removing the aliases in the windvector are described, in addition to an adaptation of the conventional maximum likelihood algorithm. The new algorithms are more effective at alias removal than the conventional one. Measurement errors for the wind speed, assuming perfect alias removal, were found to be less than 10%.

Mitigating operating room fires: development of a carbon dioxide fire prevention device.

PubMed

Culp, William C; Kimbrough, Bradly A; Luna, Sarah; Maguddayao, Aris J

2014-04-01

Operating room fires are sentinel events that present a real danger to surgical patients and occur at least as frequently as wrong-sided surgery. For fire to occur, the 3 points of the fire triad must be present: an oxidizer, an ignition source, and fuel source. The electrosurgical unit (ESU) pencil triggers most operating room fires. Carbon dioxide (CO2) is a gas that prevents ignition and suppresses fire by displacing oxygen. We hypothesize that a device can be created to reduce operating room fires by generating a cone of CO2 around the ESU pencil tip. One such device was created by fabricating a divergent nozzle and connecting it to a CO2 source. This device was then placed over the ESU pencil, allowing the tip to be encased in a cone of CO2 gas. The device was then tested in 21%, 50%, and 100% oxygen environments. The ESU was activated at 50 W cut mode while placing the ESU pencil tip on a laparotomy sponge resting on an aluminum test plate for up to 30 seconds or until the sponge ignited. High-speed videography was used to identify time of ignition. Each test was performed in each oxygen environment 5 times with the device activated (CO2 flow 8 L/min) and with the device deactivated (no CO2 flow-control). In addition, 3-dimensional spatial mapping of CO2 concentrations was performed with a CO2 sampling device. The median ± SD [range] ignition time of the control group in 21% oxygen was 2.9 s ± 0.44 [2.3-3.0], in 50% oxygen 0.58 s ± 0.12 [0.47-0.73], and in 100% oxygen 0.48 s ± 0.50 [0.03-1.27]. Fires were ignited with each control trial (15/15); no fires ignited when the device was used (0/15, P < 0.0001). The CO2 concentration at the end of the ESU pencil tip was 95%, while the average CO2 concentration 1 to 1.4 cm away from the pencil tip on the bottom plane was 64%. In conclusion, an operating room fire prevention device can be created by using a divergent nozzle design through which CO2 passes, creating a cone of fire suppressant. This device as demonstrated in a flammability model effectively reduced the risk of fire. CO2 3-dimensional spatial mapping suggests effective fire reduction at least 1 cm away from the tip of the ESU pencil at 8 L/min CO2 flow. Future testing should determine optimum CO2 flow rates and ideal nozzle shapes. Use of this device may substantially reduce the risk of patient injury due to operating room fires.

Shipyard Marking Methods

DTIC Science & Technology

1980-09-01

K ( 7 ) D , SOAPSTONE ( 1 3 ) E. lNK (5) F. CRAYON OR PAINT STICK (14) G.DYE (1) H . PE N C I L ( 1 ) 1. ELECTRIC ENGRAVING (1) 2. WHO MANUFACTURES...CHALK ( 2 ) D . DYE (1) H, SOAPSTONE (4) 4. W HAT TYPE OF DISPENSING METHOD IS UTILIZED WITH MARKING MATERIALS? A . BALL POINT TUBE ( 1 3 ) H , STEEL...9 ) L, BAMBOO PEN & INK POT F. SOAPSTONE (12) M . OIL PENCIL ( 1 ) G . L A C S T I C K ( 0 ) N . ELECTRI c ENGRAVER (1) 5, ARE STANDARD COLORS

Gender plays no role in student ability to perform on computer-based examinations

PubMed Central

Kies, Susan M; Williams, Benjamin D; Freund, Gregory G

2006-01-01

Background To see if there is a difference in performance when students switch from traditional paper-and-pencil examinations to computer-based examinations, and to determine whether there are gender differences in student performance in these two examination formats. Methods This study involved first year medical students at the University of Illinois at Urbana-Champaign over three Academic Years 2002–03/2003–04 and 2003–05. Comparisons of student performance by overall class and gender were made. Specific comparisons within courses that utilized both the paper-and-pencil and computer formats were analyzed. Results Overall performance scores for students among the various Academic Years revealed no differences between exams given in the traditional pen-and-paper and computer formats. Further, when we looked specifically for gender differences in performance between these two testing formats, we found none. Conclusion The format for examinations in the courses analyzed does not affect student performance. We find no evidence for gender differences in performance on exams on pen-and-paper or computer-based exams. PMID:17132169

Sensitive and selective determination of Cu2+ at D-penicillamine functionalized nano-cellulose modified pencil graphite electrode

NASA Astrophysics Data System (ADS)

Taheri, M.; Ahour, F.; Keshipour, S.

2018-06-01

A novel electrochemical sensor based on D-penicillamine anchored nano-cellulose (DPA-NC) modified pencil graphite electrode was fabricated and used for highly selective and sensitive determination of copper (II) ions in the picomolar concentration by square wave adsorptive stripping voltammetric (SWV) method. The modified electrode showed better and increased SWV response compared to the bare and NC modified electrodes which may be related to the porous structure of modifier along with formation of complex between Cu2+ ions and nitrogen or oxygen containing groups in DPA-NC. Optimization of various experimental parameters influence the performance of the sensor, were investigated. Under optimized condition, DPA-NC modified electrode was used for the analysis of Cu2+ in the concentration range from 0.2 to 50 pM, and a lower detection limit of 0.048 pM with good stability, repeatability, and selectivity. Finally, the practical applicability of DPA-NC-PGE was confirmed via measuring trace amount of Cu (II) in tap and river water samples.

Differential pulse voltammetric determination of acyclovir in pharmaceutical preparations using a pencil graphite electrode.

PubMed

Dilgin, Didem Giray; Karakaya, Serkan

2016-06-01

In this study, a new selective and sensitive voltammetric procedure for determination of acyclovir (ACV) was proposed using a disposable electrode, pencil graphite electrode (PGE). Cyclic and differential pulse voltammograms of ACV were recorded in Britton-Robinson buffer solution containing 0.10 M KCl with pH of 4.0 at PGE. The PGE displayed a very good electrochemical behavior with significant enhancement of the peak current compared to a glassy carbon electrode (GCE). Under experimental conditions, the PGE had a linear response range from 1.0 μM to 100.0 μM ACV with a detection limit of 0.3 μM (based on 3 Sb). Relative standard deviations of 4.8 and 3.6% were obtained for five successive determinations of 10.0 and 50.0 μM ACV, respectively, which indicate acceptable repeatability. This voltammetric method was successfully applied to the direct determination of ACV in real pharmaceutical samples. The effect of various interfering compounds on the ACV peak current was studied. Copyright © 2016 Elsevier B.V. All rights reserved.

Fluence inhomogeneities due to a ripple filter induced Moiré effect.

PubMed

Ringbæk, Toke Printz; Brons, Stephan; Naumann, Jakob; Ackermann, Benjamin; Horn, Julian; Latzel, Harald; Scheloske, Stefan; Galonska, Michael; Bassler, Niels; Zink, Klemens; Weber, Uli

2015-02-07

At particle therapy facilities with pencil beam scanning, the implementation of a ripple filter (RiFi) broadens the Bragg peak, so fewer energy steps from the accelerator are required for a homogeneous dose coverage of the planning target volume (PTV). However, sharply focusing the scanned pencil beams at the RiFi plane by ion optical settings can lead to a Moiré effect, causing fluence inhomogeneities at the isocenter. This has been experimentally proven at the Heidelberg Ionenstrahl-Therapiezentrum (HIT), Universitätsklinikum Heidelberg, Germany. 150 MeV u(-1) carbon-12 ions are used for irradiation with a 3 mm thick RiFi. The beam is focused in front of and as close to the RiFi plane as possible. The pencil beam width is estimated to be 0.78 mm at a 93 mm distance from the RiFi. Radiographic films are used to obtain the fluence profile 30 mm in front of the isocenter, 930 mm from the RiFi. The Monte Carlo (MC) code SHIELD-HIT12A is used to determine the RiFi-induced inhomogeneities in the fluence distribution at the isocenter for a similar setup, pencil beam widths at the RiFi plane ranging from σχ(RiFi to 1.2 mm and for scanning step sizes ranging from 1.5 to 3.7 mm. The beam application and monitoring system (BAMS) used at HIT is modelled and simulated. When the width of the pencil beams at the RiFi plane is much smaller than the scanning step size, the resulting inhomogeneous fluence distribution at the RiFi plane interfers with the inhomogeneous RiFi mass distribution and fluence inhomogeneity can be observed at the isocenter as large as an 8% deviation from the mean fluence. The inverse of the fluence ripple period at the isocenter is found to be the difference between the inverse of the RiFi period and the inverse of the scanning step size. We have been able to use MC simulations to reproduce the spacing of the ripple stripes seen in films irradiated at HIT. Our findings clearly indicate that pencil beams sharply focused near the RiFi plane result in fluence inhomogeneity at the isocenter. In the normal clinical application, such a setting should generally be avoided.

WE-EF-303-08: Proton Radiography Using Pencil Beam Scanning and Novel Micromegas Detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dolney, D; Lustig, R; Teo, B

Purpose: While the energy of therapeutic proton beams can be adjusted to penetrate to any given depth in water, range uncertainties arise in patients due in part to imprecise knowledge of the stopping power of protons in human tissues. Proton radiography is one approach to reduce the beam range uncertainty, thereby allowing for a reduction in treatment margins and dose escalation. Methods: The authors have adapted a novel detector technology based on Micromesh Gaseous Structure (“Micromegas”) for proton therapy beams and have demonstrated fine spatial and time resolution of magnetically scanned proton pencil beams, as well as wide dynamic rangemore » for dosimetry. In this work, proton radiographs were obtained using Micromegas 2D planes positioned downstream of solid water assemblies. The position-sensitive monitor chambers in the IBA proton delivery nozzle provide the beam entrance position. Results: Radiography with Micromegas detectors and actively scanned beams provide spatial resolution of up to 300 µm and water-equivalent thickness (WET) resolution as good as 0.02% (60 µm out of 31 cm total thickness), with the dose delivered to the patient kept below 2 cGy. The spatial resolution as a function of sample rate and number of delivered protons is found to be near the theoretical Cramer-Rao lower bound. Using the CR bound, we argue that the imaging dose could be further lowered to 1 mGy, while still achieving sub-mm spatial resolution, by relatively simple instrumentation upgrades and beam delivery modifications. Conclusion: For proton radiography, high spatial and WET resolution can be achieved, with minimal additional dose to patient, by using magnetically scanned proton pencil beams and Micromegas detectors.« less

SU-C-207A-02: Proton Radiography Using Pencil Beam Scanning and a Novel, Low-Cost Range Telescope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dolney, D; Mayers, G; Newcomer, M

Purpose: While the energy of therapeutic proton beams can be adjusted to penetrate to any given depth in water, range uncertainties arise in patients due in part to imprecise knowledge of the stopping power of protons in human tissues [1]. Proton radiography is one approach to reduce the beam range uncertainty [2], thereby allowing for a reduction in treatment margins and dose escalation. Methods: The authors have adapted a novel detector technology based on Micromesh Gaseous Structure (“Micromegas”) for proton therapy beams and have demonstrated fine spatial and time resolution of magnetically scanned proton pencil beams, as well as widemore » dynamic range for dosimetry [3]. The authors have constructed a prototype imaging system comprised of 5 Micromegas layers. Proton radiographs were obtained downstream of solid water assemblies. The position-sensitive monitor chambers in the IBA proton delivery nozzle provide the beam entrance position. Results: Our technique achieves spatial resolution as low as 300 µm and water-equivalent thickness (WET) resolution as good as 0.02% (60 µm out of 31 cm total thickness). The dose delivered to the patient is kept below 2 cGy. The spatial resolution as a function of sample rate and number of delivered protons is found to be near the theoretical Cramer-Rao lower bound. By extrapolating the CR bound, we argue that the imaging dose could be further lowered to 1 mGy, while still achieving submillimeter spatial resolution, by achievable instrumentation and beam delivery modifications. Conclusion: For proton radiography, high spatial and WET resolution can be achieved, with minimal additional dose to patient, by using magnetically scanned proton pencil beams and Micromegas detectors.« less

Collecting verbal autopsies: improving and streamlining data collection processes using electronic tablets.

PubMed

Flaxman, Abraham D; Stewart, Andrea; Joseph, Jonathan C; Alam, Nurul; Alam, Sayed Saidul; Chowdhury, Hafizur; Mooney, Meghan D; Rampatige, Rasika; Remolador, Hazel; Sanvictores, Diozele; Serina, Peter T; Streatfield, Peter Kim; Tallo, Veronica; Murray, Christopher J L; Hernandez, Bernardo; Lopez, Alan D; Riley, Ian Douglas

2018-02-01

There is increasing interest in using verbal autopsy to produce nationally representative population-level estimates of causes of death. However, the burden of processing a large quantity of surveys collected with paper and pencil has been a barrier to scaling up verbal autopsy surveillance. Direct electronic data capture has been used in other large-scale surveys and can be used in verbal autopsy as well, to reduce time and cost of going from collected data to actionable information. We collected verbal autopsy interviews using paper and pencil and using electronic tablets at two sites, and measured the cost and time required to process the surveys for analysis. From these cost and time data, we extrapolated costs associated with conducting large-scale surveillance with verbal autopsy. We found that the median time between data collection and data entry for surveys collected on paper and pencil was approximately 3 months. For surveys collected on electronic tablets, this was less than 2 days. For small-scale surveys, we found that the upfront costs of purchasing electronic tablets was the primary cost and resulted in a higher total cost. For large-scale surveys, the costs associated with data entry exceeded the cost of the tablets, so electronic data capture provides both a quicker and cheaper method of data collection. As countries increase verbal autopsy surveillance, it is important to consider the best way to design sustainable systems for data collection. Electronic data capture has the potential to greatly reduce the time and costs associated with data collection. For long-term, large-scale surveillance required by national vital statistical systems, electronic data capture reduces costs and allows data to be available sooner.

Measurement of Hydroxyl Radicals in Plasma Pencil by Laser Induced Fluorescence

DTIC Science & Technology

2013-07-01

31st ICPIG, July 14-19, 2013, Granada , Spain Topic number 6 Measurement of hydroxyl radicals in plasma pencil by laser induced fluorescence J...International Conference on Phenomena in Ionized Gases (31st) (ICPIG) Held in Granada , Spain on 14-19 July 2013, The original document contains color images. 14...Prescribed by ANSI Std Z39-18 31st ICPIG, July 14-19, 2013, Granada , Spain Topic number 6 camera. The fluorescence signal was significantly stronger

The Multimedia Piers-Harris Children's Self-Concept Scale 2: Its Psychometric Properties, Equivalence with the Paper-and-Pencil Version, and Respondent Preferences.

PubMed

Flahive, Mon-hsin Wang; Chuang, Ying-Chih; Li, Chien-Mo

2015-01-01

A multimedia version of Piers-Harris Children's Self-Concept Scale 2 (Piers-Harris 2) was created with audio and cartoon animation to facilitate the measurement of self-concept among younger children. This study aimed to assess the psychometric qualities of the computer version of Piers-Harris 2 scores, examine its score equivalence with the paper-and-pencil version, and survey the respondent preference of the two versions. Two hundred and forty eight Taiwanese students from the first to fourth grade were recruited. In regard to the psychometric properties, high internal consistency (α = .91) was found for the total score of multimedia Piers-Harris 2. High interscale correlations (.77 to .83) of the multimedia Piers-Harris 2 scores and the results of confirmatory factor analysis suggested the multimedia Piers-Harris 2 contained good structural characteristics. The scores of the multimedia Piers-Harris 2 also had significant correlations with the scores of the Elementary School Children's Self Concept Scale. The equality of convergence and criterion-related validities of Piers-Harris 2 scores for the multimedia and paper-and-pencil versions and the results of ICCs between the scores of the multimedia and paper-and-pencil Piers-Harris 2 suggested their high level of equivalence. Participants showed more positive attitudes towards the multimedia version.

Shear Adhesion of Tapered Nanopillar Arrays.

PubMed

Cho, Younghyun; Minsky, Helen K; Jiang, Yijie; Yin, Kaiyang; Turner, Kevin T; Yang, Shu

2018-04-04

Tapered nanopillars with various cross sections, including cone-shaped, stepwise, and pencil-like structures (300 nm in diameter at the base of the pillars and 1.1 μm in height), are prepared from epoxy resin templated by nanoporous anodic aluminum oxide (AAO) membranes. The effect of pillar geometry on the shear adhesion behavior of these nanopillar arrays is investigated via sliding experiments in a nanoindentation system. In a previous study of arrays with the same geometry, it was shown that cone-shaped nanopillars exhibit the highest adhesion under normal loading while stepwise and pencil-like nanopillars exhibit lower normal adhesion strength due to significant deformation of the pillars that occurs with increasing indentation depth. Contrary to the previous studies, here, we show that pencil-like nanopillars exhibit the highest shear adhesion strength at all indentation depths among three types of nanopillar arrays and that the shear adhesion increases with greater indentation depth due to the higher bending stiffness and closer packing of the pencil-like nanopillar array. Finite element simulations are used to elucidate the deformation of the pillars during the sliding experiments and agree with the nanoindentation-based sliding measurements. The experiments and finite element simulations together demonstrate that the shape of the nanopillars plays a key role in shear adhesion and that the mechanism is quite different from that of adhesion under normal loading.

The effects of pencil grip posture and different desk designs on handwriting performance in children with hemiplegic cerebral palsy.

PubMed

Kavak, Sermin Tukel; Bumin, Gonca

2009-01-01

The aim of this study was to investigate the effect of different ergonomic desk designs and pencil grip patterns on handwriting performance in children with hemiplegic cerebral palsy and healthy children. Twenty-six children with left hemiplegic cerebral palsy and 32 typically developing children were included. The Minnesota Handwriting Assessment was used to evaluate handwriting abilities. Pencil grip posture was assessed with a 5-point rating system. Specifically designed adjustable desks and chairs were used. Four different desk types were used in this study: 1) regular desk; 2) regular desk with a 20 degrees inclination; 3) cutout desk; and 4) cutout desk with a 20 degrees inclination. Statistically significant differences were found between both groups in terms of handwriting ability (p < 0.001). There was no significant difference regarding grip scores between children with cerebral palsy and healthy children (p > 0.05). We found that children with cerebral palsy had better performance using cutout desks in relation to rate and spacing parameters of handwriting (p < 0.05). The results of our study demonstrated that the pencil grip patterns have no effect on the handwriting parameters in both children with cerebral palsy and healthy children. It is recommended that a cutout table be used to provide more upper extremity support in handwriting activities for students with cerebral palsy.

The Multimedia Piers-Harris Children's Self-Concept Scale 2: Its Psychometric Properties, Equivalence with the Paper-and-Pencil Version, and Respondent Preferences

PubMed Central

Flahive, Mon-hsin Wang; Chuang, Ying-Chih; Li, Chien-Mo

2015-01-01

A multimedia version of Piers-Harris Children's Self-Concept Scale 2 (Piers-Harris 2) was created with audio and cartoon animation to facilitate the measurement of self-concept among younger children. This study aimed to assess the psychometric qualities of the computer version of Piers-Harris 2 scores, examine its score equivalence with the paper-and-pencil version, and survey the respondent preference of the two versions. Two hundred and forty eight Taiwanese students from the first to fourth grade were recruited. In regard to the psychometric properties, high internal consistency (α = .91) was found for the total score of multimedia Piers-Harris 2. High interscale correlations (.77 to .83) of the multimedia Piers-Harris 2 scores and the results of confirmatory factor analysis suggested the multimedia Piers-Harris 2 contained good structural characteristics. The scores of the multimedia Piers-Harris 2 also had significant correlations with the scores of the Elementary School Children’s Self Concept Scale. The equality of convergence and criterion-related validities of Piers-Harris 2 scores for the multimedia and paper-and-pencil versions and the results of ICCs between the scores of the multimedia and paper-and-pencil Piers-Harris 2 suggested their high level of equivalence. Participants showed more positive attitudes towards the multimedia version. PMID:26252499

Label-Free Electrochemical Detection of the Specific Oligonucleotide Sequence of Dengue Virus Type 1 on Pencil Graphite Electrodes

PubMed Central

Souza, Elaine; Nascimento, Gustavo; Santana, Nataly; Ferreira, Danielly; Lima, Manoel; Natividade, Edna; Martins, Danyelly; Lima-Filho, José

2011-01-01

A biosensor that relies on the adsorption immobilization of the 18-mer single-stranded nucleic acid related to dengue virus gene 1 on activated pencil graphite was developed. Hybridization between the probe and its complementary oligonucleotides (the target) was investigated by monitoring guanine oxidation by differential pulse voltammetry (DPV). The pencil graphite electrode was made of ordinary pencil lead (type 4B). The polished surface of the working electrode was activated by applying a potential of 1.8 V for 5 min. Afterward, the dengue oligonucleotides probe was immobilized on the activated electrode by applying 0.5 V to the electrode in 0.5 M acetate buffer (pH 5.0) for 5 min. The hybridization process was carried out by incubating at the annealing temperature of the oligonucleotides. A time of five minutes and concentration of 1 μM were found to be the optimal conditions for probe immobilization. The electrochemical detection of annealing between the DNA probe (TS-1P) immobilized on the modified electrode, and the target (TS-1T) was achieved. The target could be quantified in a range from 1 to 40 nM with good linearity and a detection limit of 0.92 nM. The specificity of the electrochemical biosensor was tested using non-complementary sequences of dengue virus 2 and 3. PMID:22163916

Disulphide linkage: To get cleaved or not? Bulk and nano copper based SERS of cystine

NASA Astrophysics Data System (ADS)

P. J., Arathi; Seemesh, Bhaskar; Rajendra Kumar Reddy, G.; Suresh Kumar, P.; Ramanathan, V.

2018-05-01

Different nano-structures of noble metals have been the conventional substrates for carrying out Surface Enhanced Raman Spectroscopy (SERS). In this paper we examine electrodeposited copper (Cu) nano-structures on pencil graphite as novel substrate to carry out SERS measurements by considering L-cystine (Cys-Cys) (dimer of the amino acid cysteine) as the probe. The formation of monolayer of the probe molecule on the substrates was confirmed using cyclic voltammetric measurements. Mode of adsorption of Cys-Cys was observed to be different on bulk Cu (taken in the wire form) and nano-structured Cu on pencil graphite. Whereas in the former the disulphide bond of Cys-Cys remained intact, it got cleaved when Cys-Cys was adsorbed on electrodeposited copper indicating the activated nature of the nano-structure compared to bulk copper. Csbnd S stretching mode of vibration underwent blue shift in Cys-Cys adsorbed on Cu on pencil graphite vis-à-vis Cys-Cys adsorbed on Cu wire. Further evidence on the cleavage of the Csbnd S bond on an activated substrate was obtained by considering a bimetallic substrate comprising of silver on copper which was electrodeposited on pencil graphite. Our studies have demonstrated that nano-copper surface is an excellent substrate for SERS giving 200 μM as lower detection limit for Cys-Cys.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang, Bin; Li, Yongbao; Liu, Bo

Purpose: CyberKnife system is initially equipped with fixed circular cones for stereotactic radiosurgery. Two dose calculation algorithms, Ray-Tracing and Monte Carlo, are available in the supplied treatment planning system. A multileaf collimator system was recently introduced in the latest generation of system, capable of arbitrarily shaped treatment field. The purpose of this study is to develop a model based dose calculation algorithm to better handle the lateral scatter in an irregularly shaped small field for the CyberKnife system. Methods: A pencil beam dose calculation algorithm widely used in linac based treatment planning system was modified. The kernel parameters and intensitymore » profile were systematically determined by fitting to the commissioning data. The model was tuned using only a subset of measured data (4 out of 12 cones) and applied to all fixed circular cones for evaluation. The root mean square (RMS) of the difference between the measured and calculated tissue-phantom-ratios (TPRs) and off-center-ratio (OCR) was compared. Three cone size correction techniques were developed to better fit the OCRs at the penumbra region, which are further evaluated by the output factors (OFs). The pencil beam model was further validated against measurement data on the variable dodecagon-shaped Iris collimators and a half-beam blocked field. Comparison with Ray-Tracing and Monte Carlo methods was also performed on a lung SBRT case. Results: The RMS between the measured and calculated TPRs is 0.7% averaged for all cones, with the descending region at 0.5%. The RMSs of OCR at infield and outfield regions are both at 0.5%. The distance to agreement (DTA) at the OCR penumbra region is 0.2 mm. All three cone size correction models achieve the same improvement in OCR agreement, with the effective source shift model (SSM) preferred, due to their ability to predict more accurately the OF variations with the source to axis distance (SAD). In noncircular field validation, the pencil beam calculated results agreed well with the film measurement of both Iris collimators and the half-beam blocked field, fared much better than the Ray-Tracing calculation. Conclusions: The authors have developed a pencil beam dose calculation model for the CyberKnife system. The dose calculation accuracy is better than the standard linac based system because the model parameters were specifically tuned to the CyberKnife system and geometry correction factors. The model handles better the lateral scatter and has the potential to be used for the irregularly shaped fields. Comprehensive validations on MLC equipped system are necessary for its clinical implementation. It is reasonably fast enough to be used during plan optimization.« less

Psychological assessment via the internet: a reliability and validity study of online (vs paper-and-pencil) versions of the General Health Questionnaire-28 (GHQ-28) and the Symptoms Check-List-90-Revised (SCL-90-R).

PubMed

Vallejo, Miguel A; Jordán, Carlos M; Díaz, Marta I; Comeche, María I; Ortega, José

2007-01-31

Internet psychology services are rapidly increasing and that implies online assessment. To guarantee the results of these new online evaluation procedures, it is necessary to have reliable and valid assessment tools. In this work we analyzed the online versions of two popular psychopathology screening questionnaires: the General Health Questionnaire-28 (GHQ-28) and the Symptoms Check-List-90-Revised (SCL-90-R). A total of 185 psychology students were recruited from two universities in Madrid, Spain. All of them had Internet access at home. A test-retest situation and factorial analysis were used to generate reliability and validity data. Both paper-and-pencil questionnaires (test) and their online versions (retest) were completed by 100 participants (median gap = 17 days). Results suggest that both online questionnaires were fairly equivalent to their paper-and-pencil versions, with higher reliability values for the SCL-90-R. Factorial analysis tended to reproduce the structure shown in former investigations of both questionnaires, replicating the four-factor structure of the GHQ-28 but failing to do so with the nine-factor structure of the SCL-90-R. Instead, a large unrotated factor appeared. Further research should be carried out to confirm these data, but our work supports the online use of both assessment tools. The psychometric properties of the online version of GHQ-28 is similar to the paper-and-pencil and we can recommend its utilization in a Web environment. In contrast, SCL-90-R can only be recommended as a global index for psychological distress, using the Global Severity Index (GSI), not necessarily its subscales; and it should be considered that the online scores were lower than the ones with the paper-and-pencil version.

Wave Propagation Through Inhomogeneities With Applications to Novel Sensing Techniques

NASA Technical Reports Server (NTRS)

Adamovsky, G.; Tokars, R.; Varga, D.; Floyd B.

2008-01-01

The paper describes phenomena observed as a result of laser pencil beam interactions with abrupt interfaces including aerodynamic shocks. Based on these phenomena, a novel flow visualization technique based on a laser scanning pencil beam is introduced. The technique reveals properties of light interaction with interfaces including aerodynamic shocks that are not seen using conventional visualization. Various configurations of scanning beam devices including those with no moving parts, as well as results of "proof-of-concept" tests, are included.

Note on the practical significance of the Drazin inverse

NASA Technical Reports Server (NTRS)

Wilkinson, J. H.

1979-01-01

The solution of the differential system Bx = Ax + f where A and B are n x n matrices, and A - Lambda B is not a singular pencil, may be expressed in terms of the Drazin inverse. It is shown that there is a simple reduced form for the pencil A - Lambda B which is adequate for the determination of the general solution and that although the Drazin inverse could be determined efficiently from this reduced form it is inadvisable to do so.

Pencil beam proton radiography using a multilayer ionization chamber

NASA Astrophysics Data System (ADS)

Farace, Paolo; Righetto, Roberto; Meijers, Arturs

2016-06-01

A pencil beam proton radiography (PR) method, using a commercial multilayer ionization chamber (MLIC) integrated with a treatment planning system (TPS) was developed. A Giraffe (IBA Dosimetry) MLIC (±0.5 mm accuracy) was used to obtain pencil beam PR by delivering spots uniformly positioned at a 5.0 mm distance in a 9  ×  9 square of spots. PRs of an electron-density (with tissue-equivalent inserts) phantom and a head phantom were acquired. The integral depth dose (IDD) curves of the delivered spots were computed by the TPS in a volume of water simulating the MLIC, and virtually added to the CT at the exit side of the phantoms. For each spot, measured and calculated IDD were overlapped in order to compute a map of range errors. On the head-phantom, the maximum dose from PR acquisition was estimated. Additionally, on the head phantom the impact on the range errors map was estimated in case of a 1 mm position misalignment. In the electron-density phantom, range errors were within 1 mm in the soft-tissue rods, but greater in the dense-rod. In the head-phantom the range errors were  -0.9  ±  2.7 mm on the whole map and within 1 mm in the brain area. On both phantoms greater errors were observed at inhomogeneity interfaces, due to sensitivity to small misalignment, and inaccurate TPS dose computation. The effect of the 1 mm misalignment was clearly visible on the range error map and produced an increased spread of range errors (-1.0  ±  3.8 mm on the whole map). The dose to the patient for such PR acquisitions would be acceptable as the maximum dose to the head phantom was  <2cGyE. By the described 2D method, allowing to discriminate misalignments, range verification can be performed in selected areas to implement an in vivo quality assurance program.

Pencil beam proton radiography using a multilayer ionization chamber.

PubMed

Farace, Paolo; Righetto, Roberto; Meijers, Arturs

2016-06-07

A pencil beam proton radiography (PR) method, using a commercial multilayer ionization chamber (MLIC) integrated with a treatment planning system (TPS) was developed. A Giraffe (IBA Dosimetry) MLIC (±0.5 mm accuracy) was used to obtain pencil beam PR by delivering spots uniformly positioned at a 5.0 mm distance in a 9  ×  9 square of spots. PRs of an electron-density (with tissue-equivalent inserts) phantom and a head phantom were acquired. The integral depth dose (IDD) curves of the delivered spots were computed by the TPS in a volume of water simulating the MLIC, and virtually added to the CT at the exit side of the phantoms. For each spot, measured and calculated IDD were overlapped in order to compute a map of range errors. On the head-phantom, the maximum dose from PR acquisition was estimated. Additionally, on the head phantom the impact on the range errors map was estimated in case of a 1 mm position misalignment. In the electron-density phantom, range errors were within 1 mm in the soft-tissue rods, but greater in the dense-rod. In the head-phantom the range errors were  -0.9  ±  2.7 mm on the whole map and within 1 mm in the brain area. On both phantoms greater errors were observed at inhomogeneity interfaces, due to sensitivity to small misalignment, and inaccurate TPS dose computation. The effect of the 1 mm misalignment was clearly visible on the range error map and produced an increased spread of range errors (-1.0  ±  3.8 mm on the whole map). The dose to the patient for such PR acquisitions would be acceptable as the maximum dose to the head phantom was  <2cGyE. By the described 2D method, allowing to discriminate misalignments, range verification can be performed in selected areas to implement an in vivo quality assurance program.

Minibeam Therapy With Protons and Light Ions: Physical Feasibility and Potential to Reduce Radiation Side Effects and to Facilitate Hypofractionation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dilmanian, F. Avraham, E-mail: avraham.dilmanian@stonybrook.edu; Eley, John G.; Krishnan, Sunil

2015-06-01

Purpose: Despite several advantages of proton therapy over megavoltage x-ray therapy, its lack of proximal tissue sparing is a concern. The method presented here adds proximal tissue sparing to protons and light ions by turning their uniform incident beams into arrays of parallel, small, or thin (0.3-mm) pencil or planar minibeams, which are known to spare tissues. As these minibeams penetrate the tissues, they gradually broaden and merge with each other to produce a solid beam. Methods and Materials: Broadening of 0.3-mm-diameter, 109-MeV proton pencil minibeams was measured using a stack of radiochromic films with plastic spacers. Monte Carlo simulationsmore » were used to evaluate the broadening in water of minibeams of protons and several light ions and the dose from neutron generated by collimator. Results: A central parameter was tissue depth, where the beam full width at half maximum (FWHM) reached 0.7 mm, beyond which tissue sparing decreases. This depth was 22 mm for 109-MeV protons in a film stack. It was also found by simulations in water to be 23.5 mm for 109 MeV proton pencil minibeams and 26 mm for 116 MeV proton planar minibeams. For light ions, all with 10 cm range in water, that depth increased with particle size; specifically it was 51 mm for Li-7 ions. The ∼2.7% photon equivalent neutron skin dose from the collimator was reduced 7-fold by introducing a gap between the collimator and the skin. Conclusions: Proton minibeams can be implemented at existing particle therapy centers. Because they spare the shallow tissues, they could augment the efficacy of proton therapy and light particle therapy, particularly in treating tumors that benefit from sparing of proximal tissues such as pediatric brain tumors. They should also allow hypofractionated treatment of all tumors by allowing the use of higher incident doses with less concern about proximal tissue damage.« less

Pencil Graphite Electrodes: A Versatile Tool in Electroanalysis

PubMed Central

2017-01-01

Due to their electrochemical and economical characteristics, pencil graphite electrodes (PGEs) gained in recent years a large applicability to the analysis of various types of inorganic and organic compounds from very different matrices. The electrode material of this type of working electrodes is constituted by the well-known and easy commercially available graphite pencil leads. Thus, PGEs are cheap and user-friendly and can be employed as disposable electrodes avoiding the time-consuming step of solid electrodes surface cleaning between measurements. When compared to other working electrodes PGEs present lower background currents, higher sensitivity, good reproducibility, and an adjustable electroactive surface area, permitting the analysis of low concentrations and small sample volumes without any deposition/preconcentration step. Therefore, this paper presents a detailed overview of the PGEs characteristics, designs and applications of bare, and electrochemically pretreated and chemically modified PGEs along with the corresponding performance characteristics like linear range and detection limit. Techniques used for bare or modified PGEs surface characterization are also reviewed. PMID:28255500

[Script crossing in scanning electron microscopy].

PubMed

Oehmichen, M; von Kortzfleisch, D; Hegner, B

1989-01-01

A case of mixed script in which ball point-pen ink was contaminated with typewriting prompted a survey of the literature and a systematic SEM study of mixed script with various writing instruments or inks. Mixed scripts produced with the following instruments or inks were investigated: pencil, ink/India ink, ball-pint pen, felt-tip pen, copied script and typewriter. This investigation showed SEM to be the method of choice for visualizing overlying scripts produced by different writing instruments or inks.

Pencil graphite electrodes for improved electrochemical detection of oleuropein by the combination of Natural Deep Eutectic Solvents and graphene oxide.

PubMed

Gomez, Federico J V; Spisso, Adrian; Fernanda Silva, María

2017-11-01

A novel methodology is presented for the enhanced electrochemical detection of oleuropein in complex plant matrices by Graphene Oxide Pencil Grahite Electrode (GOPGE) in combination with a buffer modified with a Natural Deep Eutectic Solvent, containing 10% (v/v) of Lactic acid, Glucose and H 2 O (LGH). The electrochemical behavior of oleuropein in the modified-working buffer was examined using differential pulse voltammetry. The combination of both modifications, NADES modified buffer and nanomaterial modified electrode, LGH-GOPGE, resulted on a signal enhancement of 5.3 times higher than the bare electrode with unmodified buffer. A calibration curve of oleuropein was performed between 0.10 to 37 μM and a good linearity was obtained with a correlation coefficient of 0.989. Detection and quantification limits of the method were obtained as 30 and 102 nM, respectively. In addition, precision studies indicated that the voltammetric method was sufficiently repeatable, %RSD 0.01 and 3.16 (n = 5) for potential and intensity, respectively. Finally, the proposed electrochemical sensor was successfully applied to the determination of oleuropein in an olive leaf extract prepared by ultrasound-assisted extraction. The results obtained with the proposed electrochemical sensor were compared with Capillary Zone Electrophoresis analysis with satisfactory results. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of Experimenter Contact, Setting, Inquiry Mode, and Race on Women's Self-Report of Sexual Attitudes and Behaviors: An Experimental Study.

PubMed

McCallum, Ethan B; Peterson, Zoë D

2015-11-01

Factors related to the research context, such as inquiry mode, setting, and experimenter contact, may affect participants' comfort with and willingness to disclose certain sexual attitudes or admit to engaging in sensitive sexual behaviors. In this study, 255 female undergraduates (42.7 % non-White) completed a survey containing measures of sexual behavior and attitudes. The level of experimenter contact (high vs. low contact), setting (in lab vs. out of lab), and inquiry mode (pencil-and-paper vs. computer) were manipulated and participants were randomly assigned to conditions. We hypothesized that low-contact, out-of-lab, computer conditions would be associated with more liberal sexual attitudes and higher rates of reported sexual behaviors than high-contact, in-lab, and paper-and-pencil conditions, respectively. Further, we hypothesized that effects would be moderated by race, such that differences would be greater for non-White participants because of concerns that reporting socially undesirable behavior might fuel racial stereotypes. For attitudinal measures, White participants endorsed more liberal attitudes toward sex in high-contact conditions and non-White participants endorsed more liberal attitudes in low-contact conditions. For behavioral measures, non-White participants reported more behaviors on pencil-and-paper surveys than on computers. White participants demonstrated no significant mode-related differences or reported more sexual behaviors in computer conditions than paper-and-pencil conditions. Overall, results suggest that experimenter contact and mode significantly impact sexual self-report and this impact is often moderated by race.

Prompt Gamma Imaging for In Vivo Range Verification of Pencil Beam Scanning Proton Therapy.

PubMed

Xie, Yunhe; Bentefour, El Hassane; Janssens, Guillaume; Smeets, Julien; Vander Stappen, François; Hotoiu, Lucian; Yin, Lingshu; Dolney, Derek; Avery, Stephen; O'Grady, Fionnbarr; Prieels, Damien; McDonough, James; Solberg, Timothy D; Lustig, Robert A; Lin, Alexander; Teo, Boon-Keng K

2017-09-01

To report the first clinical results and value assessment of prompt gamma imaging for in vivo proton range verification in pencil beam scanning mode. A stand-alone, trolley-mounted, prototype prompt gamma camera utilizing a knife-edge slit collimator design was used to record the prompt gamma signal emitted along the proton tracks during delivery of proton therapy for a brain cancer patient. The recorded prompt gamma depth detection profiles of individual pencil beam spots were compared with the expected profiles simulated from the treatment plan. In 6 treatment fractions recorded over 3 weeks, the mean (± standard deviation) range shifts aggregated over all spots in 9 energy layers were -0.8 ± 1.3 mm for the lateral field, 1.7 ± 0.7 mm for the right-superior-oblique field, and -0.4 ± 0.9 mm for the vertex field. This study demonstrates the feasibility and illustrates the distinctive benefits of prompt gamma imaging in pencil beam scanning treatment mode. Accuracy in range verification was found in this first clinical case to be better than the range uncertainty margin applied in the treatment plan. These first results lay the foundation for additional work toward tighter integration of the system for in vivo proton range verification and quantification of range uncertainties. Copyright © 2017 Elsevier Inc. All rights reserved.

Eraser-based eco-friendly fabrication of a skin-like large-area matrix of flexible carbon nanotube strain and pressure sensors

NASA Astrophysics Data System (ADS)

Sahatiya, Parikshit; Badhulika, Sushmee

2017-03-01

This paper reports a new type of electronic, recoverable skin-like pressure and strain sensor, produced on a flexible, biodegradable pencil-eraser substrate and fabricated using a solvent-free, low-cost and energy efficient process. Multi-walled carbon nanotube (MWCNT) film, the strain sensing element, was patterned on pencil eraser with a rolling pin and a pre-compaction mechanical press. This induces high interfacial bonding between the MWCNTs and the eraser substrate, which enables the sensor to achieve recoverability under ambient conditions. The eraser serves as a substrate for strain sensing, as well as acting as a dielectric for capacitive pressure sensing, thereby eliminating the dielectric deposition step, which is crucial in capacitive-based pressure sensors. The strain sensing transduction mechanism is attributed to the tunneling effect, caused by the elastic behavior of the MWCNTs and the strong mechanical interlock between MWCNTs and the eraser substrate, which restricts slippage of MWCNTs on the eraser thereby minimizing hysteresis. The gauge factor of the strain sensor was calculated to be 2.4, which is comparable to and even better than most of the strain and pressure sensors fabricated with more complex designs and architectures. The sensitivity of the capacitive pressure sensor was found to be 0.135 MPa-1.To demonstrate the applicability of the sensor as artificial electronic skin, the sensor was assembled on various parts of the human body and corresponding movements and touch sensation were monitored. The entire fabrication process is scalable and can be integrated into large areas to map spatial pressure distributions. This low-cost, easily scalable MWCNT pin-rolled eraser-based pressure and strain sensor has huge potential in applications such as artificial e-skin in flexible electronics and medical diagnostics, in particular in surgery as it provides high spatial resolution without a complex nanostructure architecture.

Eraser-based eco-friendly fabrication of a skin-like large-area matrix of flexible carbon nanotube strain and pressure sensors.

PubMed

Sahatiya, Parikshit; Badhulika, Sushmee

2017-03-03

This paper reports a new type of electronic, recoverable skin-like pressure and strain sensor, produced on a flexible, biodegradable pencil-eraser substrate and fabricated using a solvent-free, low-cost and energy efficient process. Multi-walled carbon nanotube (MWCNT) film, the strain sensing element, was patterned on pencil eraser with a rolling pin and a pre-compaction mechanical press. This induces high interfacial bonding between the MWCNTs and the eraser substrate, which enables the sensor to achieve recoverability under ambient conditions. The eraser serves as a substrate for strain sensing, as well as acting as a dielectric for capacitive pressure sensing, thereby eliminating the dielectric deposition step, which is crucial in capacitive-based pressure sensors. The strain sensing transduction mechanism is attributed to the tunneling effect, caused by the elastic behavior of the MWCNTs and the strong mechanical interlock between MWCNTs and the eraser substrate, which restricts slippage of MWCNTs on the eraser thereby minimizing hysteresis. The gauge factor of the strain sensor was calculated to be 2.4, which is comparable to and even better than most of the strain and pressure sensors fabricated with more complex designs and architectures. The sensitivity of the capacitive pressure sensor was found to be 0.135 MPa -1 .To demonstrate the applicability of the sensor as artificial electronic skin, the sensor was assembled on various parts of the human body and corresponding movements and touch sensation were monitored. The entire fabrication process is scalable and can be integrated into large areas to map spatial pressure distributions. This low-cost, easily scalable MWCNT pin-rolled eraser-based pressure and strain sensor has huge potential in applications such as artificial e-skin in flexible electronics and medical diagnostics, in particular in surgery as it provides high spatial resolution without a complex nanostructure architecture.

An iterative three-dimensional electron density imaging algorithm using uncollimated compton scattered x rays from a polyenergetic primary pencil beam.

PubMed

Van Uytven, Eric; Pistorius, Stephen; Gordon, Richard

2007-01-01

X-ray film-screen mammography is currently the gold standard for detecting breast cancer. However, one disadvantage is that it projects a three-dimensional (3D) object onto a two-dimensional (2D) image, reducing contrast between small lesions and layers of normal tissue. Another limitation is its reduced sensitivity in women with mammographically dense breasts. Computed tomography (CT) produces a 3D image yet has had a limited role in mammography due to its relatively high dose, low resolution, and low contrast. As a first step towards implementing quantitative 3D mammography, which may improve the ability to detect and specify breast tumors, we have developed an analytical technique that can use Compton scatter to obtain 3D information of an object from a single projection. Imaging material with a pencil beam of polychromatic x rays produces a characteristic scattered photon spectrum at each point on the detector plane. A comparable distribution may be calculated using a known incident x-ray energy spectrum, beam shape, and an initial estimate of the object's 3D mass attenuation and electron density. Our iterative minimization algorithm changes the initially arbitrary electron density voxel matrix to reduce regular differences between the analytically predicted and experimentally measured spectra at each point on the detector plane. The simulated electron density converges to that of the object as the differences are minimized. The reconstruction algorithm has been validated using simulated data produced by the EGSnrc Monte Carlo code system. We applied the imaging algorithm to a cylindrically symmetric breast tissue phantom containing multiple inhomogeneities. A preliminary ROC analysis scores greater than 0.96, which indicate that under the described simplifying conditions, this approach shows promise in identifying and localizing inhomogeneities which simulate 0.5 mm calcifications with an image voxel resolution of 0.25 cm and at a dose comparable to mammography.

Photographic copy of 7” x 12” black and white photograph ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Photographic copy of 7” x 12” black and white photograph of 1927 pencil drawing mounted on card stock by artist Hugh Ferris. Loose in oversized box located at the National Museum of American History, Smithsonian Institution, Archives Center, Work and Industry Division, Washington, D.C. 1927 PENCIL DRAWING MOUNTED ON CARD STOCK BY ARTIST HUGH FERRIS SHOWING EARLY DESIGN OF PROPOSED MISSISSIPPI RIVER BRIDGE. - Huey P. Long Bridge, Spanning Mississippi River approximately midway between nine & twelve mile points upstream from & west of New Orleans, Jefferson, Jefferson Parish, LA

Very unusual "needle- and pencil-like" uric acid crystals in the urine unmasked by infrared spectroscopy investigation.

PubMed

Baroni, S; Garigali, G; Primiano, A; Gervasoni, J; Fogazzi, G B

2018-04-01

In this paper we describe a case with very unusual "needle- and pencil-like" crystals, partly similar to those reported by other investigators, who considered them as due to uric acid. Quite importantly, infrared spectroscopy investigation which, to our knowledge, we have been the first to perform on this type of crystals, confirmed their nature as uric acid structures. This case demonstrates that the planet of urinary crystals still has several unknown facets and still deserves exploration. Copyright © 2018 Elsevier B.V. All rights reserved.

On the maximum off-axis gain of symmetrical pencil-beam antennas

NASA Technical Reports Server (NTRS)

Sawitz, P. H.

1977-01-01

For a general class of symmetrical pencil-beam antennas, the gain at a given off-axis angle can be maximized by choosing the proper antenna size. The maximum gain at the given angle relative to the on-axis gain is independent of the given angle and dependent only on the main-beam pattern. It is computed here for four commonly used gain functions. Its value, in all cases, is close to 4 dB. This result is important in the definition of service areas for communication and broadcast satellites.

A new approach to integrate GPU-based Monte Carlo simulation into inverse treatment plan optimization for proton therapy.

PubMed

Li, Yongbao; Tian, Zhen; Song, Ting; Wu, Zhaoxia; Liu, Yaqiang; Jiang, Steve; Jia, Xun

2017-01-07

Monte Carlo (MC)-based spot dose calculation is highly desired for inverse treatment planning in proton therapy because of its accuracy. Recent studies on biological optimization have also indicated the use of MC methods to compute relevant quantities of interest, e.g. linear energy transfer. Although GPU-based MC engines have been developed to address inverse optimization problems, their efficiency still needs to be improved. Also, the use of a large number of GPUs in MC calculation is not favorable for clinical applications. The previously proposed adaptive particle sampling (APS) method can improve the efficiency of MC-based inverse optimization by using the computationally expensive MC simulation more effectively. This method is more efficient than the conventional approach that performs spot dose calculation and optimization in two sequential steps. In this paper, we propose a computational library to perform MC-based spot dose calculation on GPU with the APS scheme. The implemented APS method performs a non-uniform sampling of the particles from pencil beam spots during the optimization process, favoring those from the high intensity spots. The library also conducts two computationally intensive matrix-vector operations frequently used when solving an optimization problem. This library design allows a streamlined integration of the MC-based spot dose calculation into an existing proton therapy inverse planning process. We tested the developed library in a typical inverse optimization system with four patient cases. The library achieved the targeted functions by supporting inverse planning in various proton therapy schemes, e.g. single field uniform dose, 3D intensity modulated proton therapy, and distal edge tracking. The efficiency was 41.6  ±  15.3% higher than the use of a GPU-based MC package in a conventional calculation scheme. The total computation time ranged between 2 and 50 min on a single GPU card depending on the problem size.

A new approach to integrate GPU-based Monte Carlo simulation into inverse treatment plan optimization for proton therapy

NASA Astrophysics Data System (ADS)

Li, Yongbao; Tian, Zhen; Song, Ting; Wu, Zhaoxia; Liu, Yaqiang; Jiang, Steve; Jia, Xun

2017-01-01

Monte Carlo (MC)-based spot dose calculation is highly desired for inverse treatment planning in proton therapy because of its accuracy. Recent studies on biological optimization have also indicated the use of MC methods to compute relevant quantities of interest, e.g. linear energy transfer. Although GPU-based MC engines have been developed to address inverse optimization problems, their efficiency still needs to be improved. Also, the use of a large number of GPUs in MC calculation is not favorable for clinical applications. The previously proposed adaptive particle sampling (APS) method can improve the efficiency of MC-based inverse optimization by using the computationally expensive MC simulation more effectively. This method is more efficient than the conventional approach that performs spot dose calculation and optimization in two sequential steps. In this paper, we propose a computational library to perform MC-based spot dose calculation on GPU with the APS scheme. The implemented APS method performs a non-uniform sampling of the particles from pencil beam spots during the optimization process, favoring those from the high intensity spots. The library also conducts two computationally intensive matrix-vector operations frequently used when solving an optimization problem. This library design allows a streamlined integration of the MC-based spot dose calculation into an existing proton therapy inverse planning process. We tested the developed library in a typical inverse optimization system with four patient cases. The library achieved the targeted functions by supporting inverse planning in various proton therapy schemes, e.g. single field uniform dose, 3D intensity modulated proton therapy, and distal edge tracking. The efficiency was 41.6  ±  15.3% higher than the use of a GPU-based MC package in a conventional calculation scheme. The total computation time ranged between 2 and 50 min on a single GPU card depending on the problem size.

A New Approach to Integrate GPU-based Monte Carlo Simulation into Inverse Treatment Plan Optimization for Proton Therapy

PubMed Central

Li, Yongbao; Tian, Zhen; Song, Ting; Wu, Zhaoxia; Liu, Yaqiang; Jiang, Steve; Jia, Xun

2016-01-01

Monte Carlo (MC)-based spot dose calculation is highly desired for inverse treatment planning in proton therapy because of its accuracy. Recent studies on biological optimization have also indicated the use of MC methods to compute relevant quantities of interest, e.g. linear energy transfer. Although GPU-based MC engines have been developed to address inverse optimization problems, their efficiency still needs to be improved. Also, the use of a large number of GPUs in MC calculation is not favorable for clinical applications. The previously proposed adaptive particle sampling (APS) method can improve the efficiency of MC-based inverse optimization by using the computationally expensive MC simulation more effectively. This method is more efficient than the conventional approach that performs spot dose calculation and optimization in two sequential steps. In this paper, we propose a computational library to perform MC-based spot dose calculation on GPU with the APS scheme. The implemented APS method performs a non-uniform sampling of the particles from pencil beam spots during the optimization process, favoring those from the high intensity spots. The library also conducts two computationally intensive matrix-vector operations frequently used when solving an optimization problem. This library design allows a streamlined integration of the MC-based spot dose calculation into an existing proton therapy inverse planning process. We tested the developed library in a typical inverse optimization system with four patient cases. The library achieved the targeted functions by supporting inverse planning in various proton therapy schemes, e.g. single field uniform dose, 3D intensity modulated proton therapy, and distal edge tracking. The efficiency was 41.6±15.3% higher than the use of a GPU-based MC package in a conventional calculation scheme. The total computation time ranged between 2 and 50 min on a single GPU card depending on the problem size. PMID:27991456

Stochastic Order Redshift Technique (SORT): a simple, efficient and robust method to improve cosmological redshift measurements

NASA Astrophysics Data System (ADS)

Tejos, Nicolas; Rodríguez-Puebla, Aldo; Primack, Joel R.

2018-01-01

We present a simple, efficient and robust approach to improve cosmological redshift measurements. The method is based on the presence of a reference sample for which a precise redshift number distribution (dN/dz) can be obtained for different pencil-beam-like sub-volumes within the original survey. For each sub-volume we then impose that: (i) the redshift number distribution of the uncertain redshift measurements matches the reference dN/dz corrected by their selection functions and (ii) the rank order in redshift of the original ensemble of uncertain measurements is preserved. The latter step is motivated by the fact that random variables drawn from Gaussian probability density functions (PDFs) of different means and arbitrarily large standard deviations satisfy stochastic ordering. We then repeat this simple algorithm for multiple arbitrary pencil-beam-like overlapping sub-volumes; in this manner, each uncertain measurement has multiple (non-independent) 'recovered' redshifts which can be used to estimate a new redshift PDF. We refer to this method as the Stochastic Order Redshift Technique (SORT). We have used a state-of-the-art N-body simulation to test the performance of SORT under simple assumptions and found that it can improve the quality of cosmological redshifts in a robust and efficient manner. Particularly, SORT redshifts (zsort) are able to recover the distinctive features of the so-called 'cosmic web' and can provide unbiased measurement of the two-point correlation function on scales ≳4 h-1Mpc. Given its simplicity, we envision that a method like SORT can be incorporated into more sophisticated algorithms aimed to exploit the full potential of large extragalactic photometric surveys.

Evaluation of a Secure Laptop-Based Testing Program in an Undergraduate Nursing Program: Students' Perspective.

PubMed

Tao, Jinyuan; Gunter, Glenda; Tsai, Ming-Hsiu; Lim, Dan

2016-01-01

Recently, the many robust learning management systems, and the availability of affordable laptops, have made secure laptop-based testing a reality on many campuses. The undergraduate nursing program at the authors' university began to implement a secure laptop-based testing program in 2009, which allowed students to use their newly purchased laptops to take quizzes and tests securely in classrooms. After nearly 5 years' secure laptop-based testing program implementation, a formative evaluation, using a mixed method that has both descriptive and correlational data elements, was conducted to seek constructive feedback from students to improve the program. Evaluation data show that, overall, students (n = 166) believed the secure laptop-based testing program helps them get hands-on experience of taking examinations on the computer and gets them prepared for their computerized NCLEX-RN. Students, however, had a lot of concerns about laptop glitches and campus wireless network glitches they experienced during testing. At the same time, NCLEX-RN first-time passing rate data were analyzed using the χ2 test, and revealed no significant association between the two testing methods (paper-and-pencil testing and the secure laptop-based testing) and students' first-time NCLEX-RN passing rate. Based on the odds ratio, however, the odds of students passing NCLEX-RN the first time was 1.37 times higher if they were taught with the secure laptop-based testing method than if taught with the traditional paper-and-pencil testing method in nursing school. It was recommended to the institution that better quality of laptops needs to be provided to future students, measures needed to be taken to further stabilize the campus wireless Internet network, and there was a need to reevaluate the Laptop Initiative Program.

Web-Based Assessment of Mental Well-Being in Early Adolescence: A Reliability Study.

PubMed

Hamann, Christoph; Schultze-Lutter, Frauke; Tarokh, Leila

2016-06-15

The ever-increasing use of the Internet among adolescents represents an emerging opportunity for researchers to gain access to larger samples, which can be queried over several years longitudinally. Among adolescents, young adolescents (ages 11 to 13 years) are of particular interest to clinicians as this is a transitional stage, during which depressive and anxiety symptoms often emerge. However, it remains unclear whether these youngest adolescents can accurately answer questions about their mental well-being using a Web-based platform. The aim of the study was to examine the accuracy of responses obtained from Web-based questionnaires by comparing Web-based with paper-and-pencil versions of depression and anxiety questionnaires. The primary outcome was the score on the depression and anxiety questionnaires under two conditions: (1) paper-and-pencil and (2) Web-based versions. Twenty-eight adolescents (aged 11-13 years, mean age 12.78 years and SD 0.78; 18 females, 64%) were randomly assigned to complete either the paper-and-pencil or the Web-based questionnaire first. Intraclass correlation coefficients (ICCs) were calculated to measure intrarater reliability. Intraclass correlation coefficients were calculated separately for depression (Children's Depression Inventory, CDI) and anxiety (Spence Children's Anxiety Scale, SCAS) questionnaires. On average, it took participants 17 minutes (SD 6) to answer 116 questions online. Intraclass correlation coefficient analysis revealed high intrarater reliability when comparing Web-based with paper-and-pencil responses for both CDI (ICC=.88; P<.001) and the SCAS (ICC=.95; P<.001). According to published criteria, both of these values are in the "almost perfect" category indicating the highest degree of reliability. The results of the study show an excellent reliability of Web-based assessment in 11- to 13-year-old children as compared with the standard paper-pencil assessment. Furthermore, we found that Web-based assessments with young adolescents are highly feasible, with all enrolled participants completing the Web-based form. As early adolescence is a time of remarkable social and behavioral changes, these findings open up new avenues for researchers from diverse fields who are interested in studying large samples of young adolescents over time.

Evaluation of the Efficacy of the Plasma Pencil Against Cancer Cells

NASA Astrophysics Data System (ADS)

Mohades, Soheila; Barekzi, Nazir; Razavi, Hamid; Laroussi, Mounir

2014-10-01

The plasma pencil generates low temperature and atmospheric pressure plasma. To generate the plasma, high voltage pulses with short width (from nanosecond to microsecond) are applied to a noble gas. The working gas can be helium, argon or a mixture of these with air or oxygen. Generating plasma with helium provides a tolerable temperature for biological cells and tissues. Diagnostic measurements on the plasma plume has revealed the presence of active agents such as reactive oxygen species (ROS) and nitrogen reactive species (RNS), which are known to have biological implications. Recently, low temperature plasma has drawn attention to its potential in cancer therapy. In our lab, the plasma pencil has been used to treat leukemia, prostate and epithelial cancer cells. The cancer cell line used here is the SCaBER (ATCC®HTB3™) cell line originating from a human bladder cancer. The results indicate that specific species induce the molecular mechanisms associated with cell death. The death of cells after plasma treatment will be studied using assays, such as DNA laddering and Caspase-3 activation, to elucidate the mechanism of the apoptotic or necrotic pathways.

Telemonitoring with respect to Mood Disorders and Information and Communication Technologies: Overview and Presentation of the PSYCHE Project

PubMed Central

Javelot, Hervé; Spadazzi, Anne; Weiner, Luisa; Garcia, Sonia; Gentili, Claudio; Kosel, Markus; Bertschy, Gilles

2014-01-01

This paper reviews what we know about prediction in relation to mood disorders from the perspective of clinical, biological, and physiological markers. It then also presents how information and communication technologies have developed in the field of mood disorders, from the first steps, for example, the transition from paper and pencil to more sophisticated methods, to the development of ecological momentary assessment methods and, more recently, wearable systems. These recent developments have paved the way for the use of integrative approaches capable of assessing multiple variables. The PSYCHE project stands for Personalised monitoring SYstems for Care in mental HEalth. PMID:25050321

Telemonitoring with respect to mood disorders and information and communication technologies: overview and presentation of the PSYCHE project.

PubMed

Javelot, Hervé; Spadazzi, Anne; Weiner, Luisa; Garcia, Sonia; Gentili, Claudio; Kosel, Markus; Bertschy, Gilles

2014-01-01

This paper reviews what we know about prediction in relation to mood disorders from the perspective of clinical, biological, and physiological markers. It then also presents how information and communication technologies have developed in the field of mood disorders, from the first steps, for example, the transition from paper and pencil to more sophisticated methods, to the development of ecological momentary assessment methods and, more recently, wearable systems. These recent developments have paved the way for the use of integrative approaches capable of assessing multiple variables. The PSYCHE project stands for Personalised monitoring SYstems for Care in mental HEalth.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Verburg, J; Bortfeld, T

Purpose: We present a new system to perform prompt gamma-ray spectroscopy during proton pencil-beam scanning treatments, which enables in vivo verification of the proton range. This system will be used for the first clinical studies of this technology. Methods: After successful pre-clinical testing of prompt gamma-ray spectroscopy, a full scale system for clinical studies is now being assembled. Prompt gamma-rays will be detected during patient treatment using an array of 8 detector modules arranged behind a tungsten collimator. Each detector module consists of a lanthanum(III) bromide scintillator, a photomultiplier tube, and custom electronics for stable high voltage supply and signalmore » amplification. A new real-time data acquisition and control system samples the signals from the detectors with analog-to-digital converters, analyses events of interest, and communicates with the beam delivery systems. The timing of the detected events was synchronized to the cyclotron radiofrequency and the pencil-beam delivery. Range verification is performed by matching measured energy- and timeresolved gamma-ray spectra to nuclear reaction models based on the clinical treatment plan. Experiments in phantoms were performed using clinical beams in order to assess the performance of the systems. Results: The experiments showed reliable real-time analysis of more than 10 million detector events per second. The individual detector modules acquired accurate energy- and time-resolved gamma-ray measurements at a rate of 1 million events per second, which is typical for beams delivered with a clinical dose rate. The data acquisition system successfully tracked the delivery of the scanned pencil-beams to determine the location of range deviations within the treatment field. Conclusion: A clinical system for proton range verification using prompt gamma-ray spectroscopy has been designed and is being prepared for use during patient treatments. We anticipate to start a first clinical study in the near future. This work was supported by the Federal Share of program income earned by Massachusetts; General Hospital on C06-CA059267, Proton Therapy Research and Treatment Center.« less

e-HCL-32: a useful, valid and user friendly tool in the screening of bipolar II disorder.

PubMed

Hidalgo-Mazzei, Diego; Mateu, Ainoa; Undurraga, Juan; Rosa, Adriane R; Pacchiarotti, Isabella; Bonnin, Caterina del Mar; Sánchez-Moreno, José; Colom, Francesc; Vieta, Eduard

2015-01-01

Bipolar type II (BDII) is a frequent disorder with high morbidity and mortality, characterized by depressive and hypomanic episodes. Early diagnosis can be effective in improving long-term prognosis. However, diagnosing BDII is challenging due to the difficulty in detecting past hypomanic episodes. The HCL-32 is a widely used and reliable screening instrument for the detection of past hypomanic episodes. Making this tool available to more patients could help diagnose and treat undetected cases of BDII earlier. New technologies such as the Internet have been previously used for this purpose with favorable outcomes. Accordingly, the objective of this study is to evaluate the acceptability, validity, reliability and equivalence of an online version of this questionnaire. From May 2012 to March 2013, 52 participants attending an outpatient mental health clinic completed a paper version of the HCL-32 (HCL-32) and its online version (e-HCL-32) within two weeks. After its completion, they were asked to answer a brief satisfaction survey. No differences were found (HCL-32 mean total score=17.73 (SD=7.37), e-HCL-32 mean total score=18.28 (SD=7.09). T=-1.720, p=0.092, 95% CI=-1.21 to 0.09) between the results of the paper and pencil HCL-32 compared to its online version (e-HCL-32). The psychometric properties of the online version of the hypomania checklist (e-HCL-32) were good and comparable to the paper and pencil version. 80% of participants found online questionnaires to be easier to answer and more user-friendly. The results of this study support the use of an online screening tool for the detection of previous hypomanic episodes (necessary for BDII diagnosis) as it showed to have a similar validity and reliability to the traditional paper and pencil method. Copyright © 2014 Elsevier Inc. All rights reserved.

Stereotactic, Single-Dose Irradiation of Lung Tumors: A Comparison of Absolute Dose and Dose Distribution Between Pencil Beam and Monte Carlo Algorithms Based on Actual Patient CT Scans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen Huixiao; Lohr, Frank; Fritz, Peter

2010-11-01

Purpose: Dose calculation based on pencil beam (PB) algorithms has its shortcomings predicting dose in tissue heterogeneities. The aim of this study was to compare dose distributions of clinically applied non-intensity-modulated radiotherapy 15-MV plans for stereotactic body radiotherapy between voxel Monte Carlo (XVMC) calculation and PB calculation for lung lesions. Methods and Materials: To validate XVMC, one treatment plan was verified in an inhomogeneous thorax phantom with EDR2 film (Eastman Kodak, Rochester, NY). Both measured and calculated (PB and XVMC) dose distributions were compared regarding profiles and isodoses. Then, 35 lung plans originally created for clinical treatment by PB calculationmore » with the Eclipse planning system (Varian Medical Systems, Palo Alto, CA) were recalculated by XVMC (investigational implementation in PrecisePLAN [Elekta AB, Stockholm, Sweden]). Clinically relevant dose-volume parameters for target and lung tissue were compared and analyzed statistically. Results: The XVMC calculation agreed well with film measurements (<1% difference in lateral profile), whereas the deviation between PB calculation and film measurements was up to +15%. On analysis of 35 clinical cases, the mean dose, minimal dose and coverage dose value for 95% volume of gross tumor volume were 1.14 {+-} 1.72 Gy, 1.68 {+-} 1.47 Gy, and 1.24 {+-} 1.04 Gy lower by XVMC compared with PB, respectively (prescription dose, 30 Gy). The volume covered by the 9 Gy isodose of lung was 2.73% {+-} 3.12% higher when calculated by XVMC compared with PB. The largest differences were observed for small lesions circumferentially encompassed by lung tissue. Conclusions: Pencil beam dose calculation overestimates dose to the tumor and underestimates lung volumes exposed to a given dose consistently for 15-MV photons. The degree of difference between XVMC and PB is tumor size and location dependent. Therefore XVMC calculation is helpful to further optimize treatment planning.« less

SU-F-T-270: A Technique for Modeling a Diode Array Into the TPS for Lung SBRT Patient Specific QA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Curley, C; Leventouri, T; Ouhib, Z

2016-06-15

Purpose: To accurately match the treatment planning system (TPS) with the measurement environment, where quality assurance (QA) devices are used to collect data, for lung Stereotactic Body Radiation Therapy (SBRT) patient specific QA. Incorporation of heterogeneities is also studied. Methods: Dual energy computerized tomography (DECT) and single energy computerized tomography (SECT) were used to model phantoms incorporating a 2-D diode array into the TPS. A water-equivalent and a heterogeneous phantom (simulating the thoracic region of a patient) were studied. Monte Carlo and pencil beam planar dose distributions were compared to measured distributions. Composite and individual fields were analyzed for normallymore » incident and planned gantry angle deliveries. γ- analysis was used with criteria 3% 3mm, 2% 2mm, and 1% 1mm. Results: The Monte Carlo calculations for the DECT resulted in improved agreements with the diode array for 46.4% of the fields at 3% 3mm, 85.7% at 2% 2mm, and 92.9% at 1% 1mm.For the SECT, the Monte Carlo calculations gave no agreement for the same γ-analysis criteria. Pencil beam calculations resulted in lower agreements with the diode array in the TPS. The DECT showed improvements for 14.3% of the fields at 3% 3mm and 2% 2mm, and 28.6% at 1% 1mm.In SECT comparisons, 7.1% of the fields at 3% 3mm, 10.7% at 2% 2mm, and 17.9% at 1% 1mm showed improved agreements with the diode array. Conclusion: This study demonstrates that modeling the diode array in the TPS is viable using DECT with Monte Carlo for patient specific lung SBRT QA. As recommended by task groups (e.g. TG 65, TG 101, TG 244) of the American Association of Physicists in Medicine (AAPM), pencil beam algorithms should be avoided in the presence of heterogeneous materials, including a diode array.« less

Minibeam therapy with protons and light ions: physical feasibility and potential to reduce radiation side effects and to facilitate hypofractionation.

PubMed

Dilmanian, F Avraham; Eley, John G; Krishnan, Sunil

2015-06-01

Despite several advantages of proton therapy over megavoltage x-ray therapy, its lack of proximal tissue sparing is a concern. The method presented here adds proximal tissue sparing to protons and light ions by turning their uniform incident beams into arrays of parallel, small, or thin (0.3-mm) pencil or planar minibeams, which are known to spare tissues. As these minibeams penetrate the tissues, they gradually broaden and merge with each other to produce a solid beam. Broadening of 0.3-mm-diameter, 109-MeV proton pencil minibeams was measured using a stack of radiochromic films with plastic spacers. Monte Carlo simulations were used to evaluate the broadening in water of minibeams of protons and several light ions and the dose from neutron generated by collimator. A central parameter was tissue depth, where the beam full width at half maximum (FWHM) reached 0.7 mm, beyond which tissue sparing decreases. This depth was 22 mm for 109-MeV protons in a film stack. It was also found by simulations in water to be 23.5 mm for 109 MeV proton pencil minibeams and 26 mm for 116 MeV proton planar minibeams. For light ions, all with 10 cm range in water, that depth increased with particle size; specifically it was 51 mm for Li-7 ions. The ∼2.7% photon equivalent neutron skin dose from the collimator was reduced 7-fold by introducing a gap between the collimator and the skin. Proton minibeams can be implemented at existing particle therapy centers. Because they spare the shallow tissues, they could augment the efficacy of proton therapy and light particle therapy, particularly in treating tumors that benefit from sparing of proximal tissues such as pediatric brain tumors. They should also allow hypofractionated treatment of all tumors by allowing the use of higher incident doses with less concern about proximal tissue damage. Copyright © 2015 Elsevier Inc. All rights reserved.

Treatment planning for radiotherapy with very high-energy electron beams and comparison of VHEE and VMAT plans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bazalova-Carter, Magdalena; Qu, Bradley; Palma, Bianey

2015-05-15

Purpose: The aim of this work was to develop a treatment planning workflow for rapid radiotherapy delivered with very high-energy electron (VHEE) scanning pencil beams of 60–120 MeV and to study VHEE plans as a function of VHEE treatment parameters. Additionally, VHEE plans were compared to clinical state-of-the-art volumetric modulated arc therapy (VMAT) photon plans for three cases. Methods: VHEE radiotherapy treatment planning was performed by linking EGSnrc Monte Carlo (MC) dose calculations with inverse treatment planning in a research version of RayStation. In order to study the effect of VHEE treatment parameters on VHEE dose distributions, a MATLAB graphicalmore » user interface (GUI) for calculation of VHEE MC pencil beam doses was developed. Through the GUI, pediatric case MC simulations were run for a number of beam energies (60, 80, 100, and 120 MeV), number of beams (13, 17, and 36), pencil beam spot (0.1, 1.0, and 3.0 mm) and grid (2.0, 2.5, and 3.5 mm) sizes, and source-to-axis distance, SAD (40 and 50 cm). VHEE plans for the pediatric case calculated with the different treatment parameters were optimized and compared. Furthermore, 100 MeV VHEE plans for the pediatric case, a lung, and a prostate case were calculated and compared to the clinically delivered VMAT plans. All plans were normalized such that the 100% isodose line covered 95% of the target volume. Results: VHEE beam energy had the largest effect on the quality of dose distributions of the pediatric case. For the same target dose, the mean doses to organs at risk (OARs) decreased by 5%–16% when planned with 100 MeV compared to 60 MeV, but there was no further improvement in the 120 MeV plan. VHEE plans calculated with 36 beams outperformed plans calculated with 13 and 17 beams, but to a more modest degree (<8%). While pencil beam spacing and SAD had a small effect on VHEE dose distributions, 0.1–3 mm pencil beam sizes resulted in identical dose distributions. For the 100 MeV VHEE pediatric plan, OAR doses were up to 70% lower and the integral dose was 33% lower for VHEE compared to 6 MV VMAT. Additionally, VHEE conformity indices (CI{sub 100} = 1.09 and CI{sub 50} = 4.07) were better than VMAT conformity indices (CI{sub 100} = 1.30 and CI{sub 50} = 6.81). The 100 MeV VHEE lung plan resulted in mean dose decrease to all OARs by up to 27% for the same target coverage compared to the clinical 6 MV flattening filter-free (FFF) VMAT plan. The 100 MeV prostate plan resulted in 3% mean dose increase to the penile bulb and the urethra, but all other OAR mean doses were lower compared to the 15 MV VMAT plan. The lung case CI{sub 100} and CI{sub 50} conformity indices were 3% and 8% lower, respectively, in the VHEE plan compared to the VMAT plan. The prostate case CI{sub 100} and CI{sub 50} conformity indices were 1% higher and 8% lower, respectively, in the VHEE plan compared to the VMAT plan. Conclusions: The authors have developed a treatment planning workflow for MC dose calculation of pencil beams and optimization for treatment planning of VHEE radiotherapy. The authors have demonstrated that VHEE plans resulted in similar or superior dose distributions for pediatric, lung, and prostate cases compared to clinical VMAT plans.« less

The effect of guided inquiry-based instruction in secondary science for students with learning disabilities

NASA Astrophysics Data System (ADS)

Eliot, Michael H.

Students with learning disabilities (SWLDs) need to attain academic rigor to graduate from high school and college, as well as achieve success in life. Constructivist theories suggest that guided inquiry may provide the impetus for their success, yet little research has been done to support this premise. This study was designed to fill that gap. This quasi-experimental study compared didactic and guided inquiry-based teaching of science concepts to secondary SWLDs in SDC science classes. The study examined 38 students in four classes at two diverse, urban high schools. Participants were taught two science concepts using both teaching methods and posttested after each using paper-and-pencil tests and performance tasks. Data were compared to determine increases in conceptual understanding by teaching method, order of teaching method, and exposure one or both teaching methods. A survey examined participants' perceived self-efficacy under each method. Also, qualitative comparison of the two test formats examined appropriate use with SWLDs. Results showed significantly higher scores after the guided inquiry method on concept of volume, suggesting that guided inquiry does improve conceptual understanding over didactic instruction in some cases. Didactic teaching followed by guided inquiry resulted in higher scores than the reverse order, indicating that SWLDs may require direct instruction in basic facts and procedures related to a topic prior to engaging in guided inquiry. Also application of both teaching methods resulted in significantly higher scores than a single method on the concept of density, suggesting that SWLDs may require more in depth instruction found using both methods. No differences in perceived self-efficacy were shown. Qualitative analysis both assessments and participants' behaviors during testing support the use of performance tasks over paper-and-pencil tests with SWLDs. Implications for education include the use of guided inquiry to increase SWLDs conceptual understanding and process skills, while improving motivation and participation through hands-on learning. In addition, teachers may use performance tasks to better assess students' thought process, problem solving skills, and conceptual understanding. However, constructivist teaching methods require extra training, pedagogical skills, subject matter knowledge, physical resources, and support from all stakeholders.

Synchronized Drumming Enhances Activity in the Caudate and Facilitates Prosocial Commitment - If the Rhythm Comes Easily

PubMed Central

Kokal, Idil; Engel, Annerose; Kirschner, Sebastian; Keysers, Christian

2011-01-01

Why does chanting, drumming or dancing together make people feel united? Here we investigate the neural mechanisms underlying interpersonal synchrony and its subsequent effects on prosocial behavior among synchronized individuals. We hypothesized that areas of the brain associated with the processing of reward would be active when individuals experience synchrony during drumming, and that these reward signals would increase prosocial behavior toward this synchronous drum partner. 18 female non-musicians were scanned with functional magnetic resonance imaging while they drummed a rhythm, in alternating blocks, with two different experimenters: one drumming in-synchrony and the other out-of-synchrony relative to the participant. In the last scanning part, which served as the experimental manipulation for the following prosocial behavioral test, one of the experimenters drummed with one half of the participants in-synchrony and with the other out-of-synchrony. After scanning, this experimenter “accidentally” dropped eight pencils, and the number of pencils collected by the participants was used as a measure of prosocial commitment. Results revealed that participants who mastered the novel rhythm easily before scanning showed increased activity in the caudate during synchronous drumming. The same area also responded to monetary reward in a localizer task with the same participants. The activity in the caudate during experiencing synchronous drumming also predicted the number of pencils the participants later collected to help the synchronous experimenter of the manipulation run. In addition, participants collected more pencils to help the experimenter when she had drummed in-synchrony than out-of-synchrony during the manipulation run. By showing an overlap in activated areas during synchronized drumming and monetary reward, our findings suggest that interpersonal synchrony is related to the brain's reward system. PMID:22110623

Assessment of executive function in adolescence: a comparison of traditional and virtual reality tools.

PubMed

Lalonde, Gabrielle; Henry, Mylène; Drouin-Germain, Anne; Nolin, Pierre; Beauchamp, Miriam H

2013-09-30

Paper-pencil type tests are traditionally used in the assessment of executive functions (EF); however, concerns have been raised as to whether these represent actual functioning in everyday life. Virtual reality (VR) environments offer a novel alternative for the assessment of cognitive function and therefore have the potential to enhance the evaluation of EF by presenting individuals with stimuli that come closer to reproducing everyday situations. The aims of this study were to (1) establish which traditional paper-pencil EF tests from the Delis-Kaplan Executive Function System (D-KEFS) are associated with performance on a VR-Stroop task and (2) compare D-KEFS tests and the VR-Stroop task in their ability to predict everyday EF and behavior, as measured by the Behavioral Rating Inventory of Executive Function (BRIEF) and the Child Behavior Checklist (CBCL). Thirty-eight typically developing adolescents aged between 13 and 17 years completed the ClinicaVR: Classroom-Stroop, and five D-KEFS subtests (Trail Making, Tower, Twenty Questions, Verbal Fluency and Color-Word Interference). Their parents completed the BRIEF and CBCL questionnaires. The results indicate that performance on the VR-Stroop task correlates with both traditional forms of EF assessment (D-KEFS, BRIEF). In particular, performance on the VR-Stroop task was closely associated with performance on a paper-pencil inhibition task. Furthermore, VR-Stroop performance more accurately reflected everyday behavioral EF than paper-pencil tasks. VR appears to offer an ecological perspective on everyday functioning and could be seen as complementary to traditional tests in the assessment of complex cognitive abilities. Copyright © 2013 Elsevier B.V. All rights reserved.

Computer-assisted qualitative data analysis software.

PubMed

Cope, Diane G

2014-05-01

Advances in technology have provided new approaches for data collection methods and analysis for researchers. Data collection is no longer limited to paper-and-pencil format, and numerous methods are now available through Internet and electronic resources. With these techniques, researchers are not burdened with entering data manually and data analysis is facilitated by software programs. Quantitative research is supported by the use of computer software and provides ease in the management of large data sets and rapid analysis of numeric statistical methods. New technologies are emerging to support qualitative research with the availability of computer-assisted qualitative data analysis software (CAQDAS).CAQDAS will be presented with a discussion of advantages, limitations, controversial issues, and recommendations for this type of software use.

Ionization chamber-based reference dosimetry of intensity modulated radiation beams.

PubMed

Bouchard, Hugo; Seuntjens, Jan

2004-09-01

The present paper addresses reference dose measurements using thimble ionization chambers for quality assurance in IMRT fields. In these radiation fields, detector fluence perturbation effects invalidate the application of open-field dosimetry protocol data for the derivation of absorbed dose to water from ionization chamber measurements. We define a correction factor C(Q)IMRT to correct the absorbed dose to water calibration coefficient N(D, w)Q for fluence perturbation effects in individual segments of an IMRT delivery and developed a calculation method to evaluate the factor. The method consists of precalculating, using accurate Monte Carlo techniques, ionization chamber, type-dependent cavity air dose, and in-phantom dose to water at the reference point for zero-width pencil beams as a function of position of the pencil beams impinging on the phantom surface. These precalculated kernels are convolved with the IMRT fluence distribution to arrive at the dose-to-water-dose-to-cavity air ratio [D(a)w (IMRT)] for IMRT fields and with a 10x10 cm2 open-field fluence to arrive at the same ratio D(a)w (Q) for the 10x10 cm2 reference field. The correction factor C(Q)IMRT is then calculated as the ratio of D(a)w (IMRT) and D(a)w (Q). The calculation method was experimentally validated and the magnitude of chamber correction factors in reference dose measurements in single static and dynamic IMRT fields was studied. The results show that, for thimble-type ionization chambers the correction factor in a single, realistic dynamic IMRT field can be of the order of 10% or more. We therefore propose that for accurate reference dosimetry of complete n-beam IMRT deliveries, ionization chamber fluence perturbation correction factors must explicitly be taken into account.

SU-F-T-142: An Analytical Model to Correct the Aperture Scattered Dose in Clinical Proton Beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, B; Liu, S; Zhang, T

2016-06-15

Purpose: Apertures or collimators are used to laterally shape proton beams in double scattering (DS) delivery and to sharpen the penumbra in pencil beam (PB) delivery. However, aperture-scattered dose is not included in the current dose calculations of treatment planning system (TPS). The purpose of this study is to provide a method to correct the aperture-scattered dose based on an analytical model. Methods: A DS beam with a non-divergent aperture was delivered using a single-room proton machine. Dose profiles were measured with an ion-chamber scanning in water and a 2-D ion chamber matrix with solid-water buildup at various depths. Themore » measured doses were considered as the sum of the non-contaminated dose and the aperture-scattered dose. The non-contaminated dose was calculated by TPS and subtracted from the measured dose. Aperture scattered-dose was modeled as a 1D Gaussian distribution. For 2-D fields, to calculate the scatter-dose from all the edges of aperture, a sum of weighted distance was used in the model based on the distance from calculation point to aperture edge. The gamma index was calculated between the measured and calculated dose with and without scatter correction. Results: For a beam with range of 23 cm and aperture size of 20 cm, the contribution of the scatter horn was ∼8% of the total dose at 4 cm depth and diminished to 0 at 15 cm depth. The amplitude of scatter-dose decreased linearly with the depth increase. The 1D gamma index (2%/2 mm) between the calculated and measured profiles increased from 63% to 98% for 4 cm depth and from 83% to 98% at 13 cm depth. The 2D gamma index (2%/2 mm) at 4 cm depth has improved from 78% to 94%. Conclusion: Using the simple analytical method the discrepancy between the measured and calculated dose has significantly improved.« less

Spot Weight Adaptation for Moving Target in Spot Scanning Proton Therapy.

PubMed

Morel, Paul; Wu, Xiaodong; Blin, Guillaume; Vialette, Stéphane; Flynn, Ryan; Hyer, Daniel; Wang, Dongxu

2015-01-01

This study describes a real-time spot weight adaptation method in spot-scanning proton therapy for moving target or moving patient, so that the resultant dose distribution closely matches the planned dose distribution. The method proposed in this study adapts the weight (MU) of the delivering pencil beam to that of the target spot; it will actually hit during patient/target motion. The target spot that a certain delivering pencil beam may hit relies on patient monitoring and/or motion modeling using four-dimensional (4D) CT. After the adapted delivery, the required total weight [Monitor Unit (MU)] for this target spot is then subtracted from the planned value. With continuous patient motion and continuous spot scanning, the planned doses to all target spots will eventually be all fulfilled. In a proof-of-principle test, a lung case was presented with realistic temporal and motion parameters; the resultant dose distribution using spot weight adaptation was compared to that without using this method. The impact of the real-time patient/target position tracking or prediction was also investigated. For moderate motion (i.e., mean amplitude 0.5 cm), D95% to the planning target volume (PTV) was only 81.5% of the prescription (RX) dose; with spot weight adaptation PTV D95% achieves 97.7% RX. For large motion amplitude (i.e., 1.5 cm), without spot weight adaptation PTV D95% is only 42.9% of RX; with spot weight adaptation, PTV D95% achieves 97.7% RX. Larger errors in patient/target position tracking or prediction led to worse final target coverage; an error of 3 mm or smaller in patient/target position tracking is preferred. The proposed spot weight adaptation method was able to deliver the planned dose distribution and maintain target coverage when patient motion was involved. The successful implementation of this method would rely on accurate monitoring or prediction of patient/target motion.

Neurobehavioral effects of transportation noise in primary schoolchildren: a cross-sectional study

PubMed Central

2010-01-01

Background Due to shortcomings in the design, no source-specific exposure-effect relations are as yet available describing the effects of noise on children's cognitive performance. This paper reports on a study investigating the effects of aircraft and road traffic noise exposure on the cognitive performance of primary schoolchildren in both the home and the school setting. Methods Participants were 553 children (age 9-11 years) attending 24 primary schools around Schiphol Amsterdam Airport. Cognitive performance was measured by the Neurobehavioral Evaluation System (NES), and a set of paper-and-pencil tests. Multilevel regression analyses were applied to estimate the association between noise exposure and cognitive performance, accounting for demographic and school related confounders. Results Effects of school noise exposure were observed in the more difficult parts of the Switching Attention Test (SAT): children attending schools with higher road or aircraft noise levels made significantly more errors. The correlational pattern and factor structure of the data indicate that the coherence between the neurobehavioral tests and paper-and-pencil tests is high. Conclusions Based on this study and previous scientific literature it can be concluded that performance on simple tasks is less susceptible to the effects of noise than performance on more complex tasks. PMID:20515466

Impact of range shifter material on proton pencil beam spot characteristics.

PubMed

Shen, Jiajian; Liu, Wei; Anand, Aman; Stoker, Joshua B; Ding, Xiaoning; Fatyga, Mirek; Herman, Michael G; Bues, Martin

2015-03-01

To quantitatively investigate the effect of range shifter materials on single-spot characteristics of a proton pencil beam. An analytic approximation for multiple Coulomb scattering ("differential Moliere" formula) was adopted to calculate spot sizes of proton spot scanning beams impinging on a range shifter. The calculations cover a range of delivery parameters: six range shifter materials (acrylonitrile butadiene styrene, Lexan, Lucite, polyethylene, polystyrene, and wax) and water as reference material, proton beam energies ranging from 75 to 200 MeV, range shifter thicknesses of 4.5 and 7.0 g/cm(2), and range shifter positions from 5 to 50 cm. The analytic method was validated by comparing calculation results with the measurements reported in the literature. Relative to a water-equivalent reference, the spot size distal to a wax or polyethylene range shifter is 15% smaller, while the spot size distal to a range shifter made of Lexan or Lucite is about 6% smaller. The relative spot size variations are nearly independent of beam energy and range shifter thickness and decrease with smaller air gaps. Among the six material investigated, wax and polyethylene are desirable range shifter materials when the spot size is kept small. Lexan and Lucite are the desirable range shifter materials when the scattering power is kept similar to water.

Single-energy intensity modulated proton therapy

NASA Astrophysics Data System (ADS)

Farace, Paolo; Righetto, Roberto; Cianchetti, Marco

2015-09-01

In this note, an intensity modulated proton therapy (IMPT) technique, based on the use of high single-energy (SE-IMPT) pencil beams, is described. The method uses only the highest system energy (226 MeV) and only lateral penumbra to produce dose gradient, as in photon therapy. In the study, after a preliminary analysis of the width of proton pencil beam penumbras at different depths, SE-IMPT was compared with conventional IMPT in a phantom containing titanium inserts and in a patient, affected by a spinal chordoma with fixation rods. It was shown that SE-IMPT has the potential to produce a sharp dose gradient and that it is not affected by the uncertainties produced by metal implants crossed by the proton beams. Moreover, in the chordoma patient, target coverage and organ at risk sparing of the SE-IMPT plan resulted comparable to that of the less reliable conventional IMPT technique. Robustness analysis confirmed that SE-IMPT was not affected by range errors, which can drastically affect the IMPT plan. When accepting a low-dose spread as in modern photon techniques, SE-IMPT could be an option for the treatment of lesions (e.g. cervical bone tumours) where steep dose gradient could improve curability, and where range uncertainty, due for example to the presence of metal implants, hampers conventional IMPT.

Pancreatitis Quality of Life Instrument: Development of a new instrument

PubMed Central

Bova, Carol; Barton, Bruce; Hartigan, Celia

2014-01-01

Objectives: The goal of this project was to develop the first disease-specific instrument for the evaluation of quality of life in chronic pancreatitis. Methods: Focus groups and interview sessions were conducted, with chronic pancreatitis patients, to identify items felt to impact quality of life which were subsequently formatted into a paper-and-pencil instrument. This instrument was used to conduct an online survey by an expert panel of pancreatologists to evaluate its content validity. Finally, the modified instrument was presented to patients during precognitive testing interviews to evaluate its clarity and appropriateness. Results: In total, 10 patients were enrolled in the focus groups and interview sessions where they identified 50 items. Once redundant items were removed, the 40 remaining items were made into a paper-and-pencil instrument referred to as the Pancreatitis Quality of Life Instrument. Through the processes of content validation and precognitive testing, the number of items in the instrument was reduced to 24. Conclusions: This marks the development of the first disease-specific instrument to evaluate quality of life in chronic pancreatitis. It includes unique features not found in generic instruments (economic factors, stigma, and spiritual factors). Although this marks a giant step forward, psychometric evaluation is still needed prior to its clinical use. PMID:26770703

An optically stimulated luminescence system to measure dose profiles in x-ray computed tomography

NASA Astrophysics Data System (ADS)

Yukihara, E. G.; Ruan, C.; Gasparian, P. B. R.; Clouse, W. J.; Kalavagunta, C.; Ahmad, S.

2009-10-01

This paper describes an LED-based optically stimulated luminescence (OSL) system for dose profile measurements using OSL detector strips and investigates its performance in x-ray computed tomography (CT) dosimetry. To compensate for the energy response of the Al2O3:C OSL detectors, which have an effective atomic number of 11.28, field-specific energy correction factors were determined using two methods: (a) comparing the OSL profiles with ionization chamber point measurements (0.3 cm3 ionization chamber) and (b) comparing the OSL profiles integrated over a 100 mm length with 100 mm long pencil ionization chamber measurements. These correction factors were obtained for the CT body and head phantoms, central and peripheral positions and three x-ray tube potential differences (100 kVp, 120 kVp and 140 kVp). The OSL dose profiles corrected by the energy dependence agreed with the ionization chamber point measurements over the entire length of the phantom (300 mm). For 120 kVp x-ray tube potential difference, the CTDI100 values calculated using the OSL dose profiles corrected for the energy dependence and those obtained from an independent measurement with a 100 mm long pencil ionization chamber also agreed within ±5%.

Single-energy intensity modulated proton therapy.

PubMed

Farace, Paolo; Righetto, Roberto; Cianchetti, Marco

2015-10-07

In this note, an intensity modulated proton therapy (IMPT) technique, based on the use of high single-energy (SE-IMPT) pencil beams, is described.The method uses only the highest system energy (226 MeV) and only lateral penumbra to produce dose gradient, as in photon therapy. In the study, after a preliminary analysis of the width of proton pencil beam penumbras at different depths, SE-IMPT was compared with conventional IMPT in a phantom containing titanium inserts and in a patient, affected by a spinal chordoma with fixation rods.It was shown that SE-IMPT has the potential to produce a sharp dose gradient and that it is not affected by the uncertainties produced by metal implants crossed by the proton beams. Moreover, in the chordoma patient, target coverage and organ at risk sparing of the SE-IMPT plan resulted comparable to that of the less reliable conventional IMPT technique. Robustness analysis confirmed that SE-IMPT was not affected by range errors, which can drastically affect the IMPT plan.When accepting a low-dose spread as in modern photon techniques, SE-IMPT could be an option for the treatment of lesions (e.g. cervical bone tumours) where steep dose gradient could improve curability, and where range uncertainty, due for example to the presence of metal implants, hampers conventional IMPT.

The equivalence of computerized and paper-and-pencil psychological instruments: implications for measures of negative affect.

PubMed

Schulenberg, S E; Yutrzenka, B A

1999-05-01

The use of computerized psychological assessment is a growing practice among contemporary mental health professionals. Many popular and frequently used paper-and-pencil instruments have been adapted into computerized versions. Although equivalence for many instruments has been evaluated and supported, this issue is far from resolved. This literature review deals with recent research findings that suggest that computer aversion negatively impacts computerized assessment, particularly as it relates to measures of negative affect. There is a dearth of equivalence studies that take into account computer aversion's potential impact on the measurement of negative affect. Recommendations are offered for future research in this area.

The Impact of Monte Carlo Dose Calculations on Intensity-Modulated Radiation Therapy

NASA Astrophysics Data System (ADS)

Siebers, J. V.; Keall, P. J.; Mohan, R.

The effect of dose calculation accuracy for IMRT was studied by comparing different dose calculation algorithms. A head and neck IMRT plan was optimized using a superposition dose calculation algorithm. Dose was re-computed for the optimized plan using both Monte Carlo and pencil beam dose calculation algorithms to generate patient and phantom dose distributions. Tumor control probabilities (TCP) and normal tissue complication probabilities (NTCP) were computed to estimate the plan outcome. For the treatment plan studied, Monte Carlo best reproduces phantom dose measurements, the TCP was slightly lower than the superposition and pencil beam results, and the NTCP values differed little.

26. A sepia photograph, 7 1/2" x 8 1/2" oh ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

26. A sepia photograph, 7 1/2" x 8 1/2" oh semi-matte paper, aerial oblique of central Terre Haute with negative inscribed letters (prints on positive as white) along the bottom margin, "(02105-631K-118) (3-10-37. 10:30A) (R-1000) (State Normal College, Terre Haute, Ind.)" This view taken looking east shows the gas building in the near foreground right. On the reverse in red pencil, "Campus Scenes 10" and in black pencil, "1937". Source: Indiana State University Archives. - John T. Beasley Building, 632 Cherry Street (between Sixth & Seventh Streets), Terre Haute, Vigo County, IN

[Incidence of postmyelography syndrome and postmyelography complaints after lumbar puncture with the Sprotte pencil-like needle in comparison with the Quincke needle].

PubMed

Fox, R G; Reiche, W; Kiefer, M; Hagen, T; Huber, G

1996-11-01

Myelography in combination with a postmyelography CT is an important presurgical examination because of its excellent visualisation of the disc, the bone and the contrast-filled dura. Side effects after myelography can be observed in up to 50% of patients. The pathophysiological mechanism is thought to be increased cerebrospinal fluid leakage at the puncture site. Since the introduction by Sprotte in 1979 of the pencil-point needle, a modification of Whitacre's needle, fewer complaints after lumbar puncture have been reported. The aim of the study was to examine the influence of two types of needle points and the temperature (37 degrees C vs 21 degrees C) of the contrast medium (CM; iotrolan, Isovist) on the incidence of side effects of lumbar puncture for myelography. In a prospective randomized trial the incidence of complaints after lumbar puncture with intrathecal CM application was evaluated by the use of a 21-G pencil-point needle as modified by Sprotte compared to our usual 22-G needle with a Quincke bevel. Some 412 patients (201 female, 211 male; mean age 54.05 +/- 7.4 years) were investigated. Directly after examination and 1. 3 and 5 days later the patients were questioned about complaints (headache, neck stiffness nausea, vomiting, buzzing in the ear and dizziness). The results were tested by the chi square test. A significantly lower incidence of complaints was seen after lumbar puncture with the pencil-point needle/Quincke needle (headache: 6.3%/18.9%, P < 0.0001; headache lasting 3 days: 0.5%/7.8%, P < 0.0001; headache lasting 5 days: 0%/2.4%, P = 0.0305; nausea: 0%/4.9%, P = 0.0009; vomiting: 0%/3.4%, P = 0.0009; dizziness: 0%/3.4%, P = 0.0074; neck stiffness: 0%/3.4%, P = 0.0074). The temperature of the CM had no influence on the complaints. No influence was seen on the quality of the myelogram. No relation to sex and age was found. Complaints after lumbar puncture and myelography are caused by the cerebrospinal fluid leakage at the puncture site. The incidence of side effects related to this leakage can be reduced by using a pencil-point needle. The temperature of the CM has no influence on the complaints.

A rehabilitation program based on music practice for patients with unilateral spatial neglect: a single-case study.

PubMed

Guilbert, Alma; Clément, Sylvain; Moroni, Christine

2017-02-01

Two major limitations of unilateral spatial neglect (USN) rehabilitation methods are actually reported: a lack of long-term efficiency and a lack of generalization to daily life. The aim of our case study was to underline how a multisensory method-music practice-could avoid these limitations. Mrs BV suffered from a chronic severe USN. She had rehabilitation sessions of music practice over 8 weeks. An improvement of her USN was found on paper-pencil tests but also in daily activities. Benefits subsisted 4 months after rehabilitation. Music practice seemed to avoid the major limitations of USN rehabilitations and could represent a promising tool.

Scanning Mode Sensor for Detection of Flow Inhomogeneities

NASA Technical Reports Server (NTRS)

Adamovsky, Grigory (Inventor)

1998-01-01

A scanning mode sensor and method is provided for detection of flow inhomogeneities such as shock. The field of use of this invention is ground test control and engine control during supersonic flight. Prior art measuring techniques include interferometry. Schlieren, and shadowgraph techniques. These techniques. however, have problems with light dissipation. The present method and sensor utilizes a pencil beam of energy which is passed through a transparent aperture in a flow inlet in a time-sequential manner so as to alter the energy beam. The altered beam or its effects are processed and can be studied to reveal information about flow through the inlet which can in turn be used for engine control.

Scanning Mode Sensor for Detection of Flow Inhomogeneities

NASA Technical Reports Server (NTRS)

Adamovsky, Grigory (Inventor)

1996-01-01

A scanning mode sensor and method is provided for detection of flow inhomogeneities such as shock. The field of use of this invention is ground test control and engine control during supersonic flight. Prior art measuring techniques include interferometry, Schlieren, and shadowgraph techniques. These techniques, however, have problems with light dissipation. The present method and sensor utilizes a pencil beam of energy which is passed through a transparent aperture in a flow inlet in a time-sequential manner so as to alter the energy beam. The altered beam or its effects are processed and can be studied to reveal information about flow through the inlet which can in turn be used for engine control.

A pilot evaluation of a computer-based psychometric test battery designed to detect impairment in patients with cirrhosis

PubMed Central

Cook, Nicola A; Kim, Jin Un; Pasha, Yasmin; Crossey, Mary ME; Schembri, Adrian J; Harel, Brian T; Kimhofer, Torben; Taylor-Robinson, Simon D

2017-01-01

Background Psychometric testing is used to identify patients with cirrhosis who have developed hepatic encephalopathy (HE). Most batteries consist of a series of paper-and-pencil tests, which are cumbersome for most clinicians. A modern, easy-to-use, computer-based battery would be a helpful clinical tool, given that in its minimal form, HE has an impact on both patients’ quality of life and the ability to drive and operate machinery (with societal consequences). Aim We compared the Cogstate™ computer battery testing with the Psychometric Hepatic Encephalopathy Score (PHES) tests, with a view to simplify the diagnosis. Methods This was a prospective study of 27 patients with histologically proven cirrhosis. An analysis of psychometric testing was performed using accuracy of task performance and speed of completion as primary variables to create a correlation matrix. A stepwise linear regression analysis was performed with backward elimination, using analysis of variance. Results Strong correlations were found between the international shopping list, international shopping list delayed recall of Cogstate and the PHES digit symbol test. The Shopping List Tasks were the only tasks that consistently had P values of <0.05 in the linear regression analysis. Conclusion Subtests of the Cogstate battery correlated very strongly with the digit symbol component of PHES in discriminating severity of HE. These findings would indicate that components of the current PHES battery with the international shopping list tasks of Cogstate would be discriminant and have the potential to be used easily in clinical practice. PMID:28919805

The Convergence Insufficiency Treatment Trial: Design, Methods, and Baseline Data

PubMed Central

2009-01-01

Objective This report describes the design and methodology of the Convergence Insufficiency Treatment Trial (CITT), the first large-scale, placebo-controlled, randomized clinical trial evaluating treatments for convergence insufficiency (CI) in children. We also report the clinical and demographic characteristics of patients. Methods We prospectively randomized children 9 to 17 years of age to one of four treatment groups: 1) home-based pencil push-ups, 2) home-based computer vergence/accommodative therapy and pencil push-ups, 3) office-based vergence/accommodative therapy with home reinforcement, 4) office-based placebo therapy. Outcome data on the Convergence Insufficiency Symptom Survey (CISS) score (primary outcome), near point of convergence (NPC), and positive fusional vergence were collected after 12 weeks of active treatment and again at 6 and 12 months post-treatment. Results The CITT enrolled 221 children with symptomatic CI with a mean age of 12.0 years (SD = +2.3). The clinical profile of the cohort at baseline was 9Δ exophoria at near (+/− 4.4) and 2Δ exophoria (+/−2.8) at distance, CISS score = 30 (+/−9.0), NPC = 14 cm (+/− 7.5), and near positive fusional vergence break = 13 Δ (+/− 4.6). There were no statistically significant nor clinically relevant differences between treatment groups with respect to baseline characteristics (p > 0.05). Conclusion Hallmark features of the study design include formal definitions of conditions and outcomes, standardized diagnostic and treatment protocols, a placebo treatment arm, masked outcome examinations, and the CISS score outcome measure. The baseline data reported herein define the clinical profile of those enrolled into the CITT. PMID:18300086

Moving virtuality into reality: A comparison study of the effectiveness of traditional and alternative assessments of learning in a multisensory, fully immersive physics program

NASA Astrophysics Data System (ADS)

Gamor, Keysha Ingram

This paper contains a research study that investigated the relative efficacy of using both a traditional paper-and-pencil assessment instrument and an alternative, virtual reality (VR) assessment instrument to assist educators and/or instructional designers in measuring learning in a virtual reality learning environment. To this end, this research study investigated assessment in VR, with the goal of analyzing aspects of student learning in VR that are feasible to access or capture by traditional assessments and alternative assessments. The researcher also examined what additional types of learning alternative assessments may offer. More specifically, this study compared the effectiveness of a traditional method with an alternative (performance-based) method of assessment that was used to examine the ability of the tools to accurately evidence the levels of students' understanding and learning. The domain area was electrostatics, a complex, abstract multidimensional concept, with which students often experience difficulty. Outcomes of the study suggest that, in the evaluation of learning in an immersive VR learning environment, assessments would most accurately manifest student learning if the assessment measure matched the learning environment itself. In this study, learning and assessing in the VR environment yielded higher final test scores than learning in VR and testing with traditional paper-and-pencil. Being able to transfer knowledge from a VR environment to other situations is critical in demonstrating the overall level of understanding of a concept. For this reason, the researcher recommends a combination of testing measures to enhance understanding of complex, abstract concepts.

Sparsity constrained split feasibility for dose-volume constraints in inverse planning of intensity-modulated photon or proton therapy

NASA Astrophysics Data System (ADS)

Penfold, Scott; Zalas, Rafał; Casiraghi, Margherita; Brooke, Mark; Censor, Yair; Schulte, Reinhard

2017-05-01

A split feasibility formulation for the inverse problem of intensity-modulated radiation therapy treatment planning with dose-volume constraints included in the planning algorithm is presented. It involves a new type of sparsity constraint that enables the inclusion of a percentage-violation constraint in the model problem and its handling by continuous (as opposed to integer) methods. We propose an iterative algorithmic framework for solving such a problem by applying the feasibility-seeking CQ-algorithm of Byrne combined with the automatic relaxation method that uses cyclic projections. Detailed implementation instructions are furnished. Functionality of the algorithm was demonstrated through the creation of an intensity-modulated proton therapy plan for a simple 2D C-shaped geometry and also for a realistic base-of-skull chordoma treatment site. Monte Carlo simulations of proton pencil beams of varying energy were conducted to obtain dose distributions for the 2D test case. A research release of the Pinnacle 3 proton treatment planning system was used to extract pencil beam doses for a clinical base-of-skull chordoma case. In both cases the beamlet doses were calculated to satisfy dose-volume constraints according to our new algorithm. Examination of the dose-volume histograms following inverse planning with our algorithm demonstrated that it performed as intended. The application of our proposed algorithm to dose-volume constraint inverse planning was successfully demonstrated. Comparison with optimized dose distributions from the research release of the Pinnacle 3 treatment planning system showed the algorithm could achieve equivalent or superior results.

An improved amperometric L-lactate biosensor based on covalent immobilization of microbial lactate oxidase onto carboxylated multiwalled carbon nanotubes/copper nanoparticles/polyaniline modified pencil graphite electrode.

PubMed

Dagar, Kusum; Pundir, C S

2017-01-01

An improved amperometric l-lactate biosensor was constructed based on covalent immobilization of lactate oxidase (LOx) from Pediococcus species onto carboxylated multiwalled carbon nanotubes (cMWCNT)/copper nanoparticles (CuNPs)/polyaniline (PANI) hybrid film electrodeposited on the surface of a pencil graphite electrode (PGE). The enzyme electrode was characterized by cyclic voltammetry (CV), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and electrochemical impedance spectroscopy (EIS), while CuNPs synthesized by chemical reduction method, were characterized by transmission electron microscopy (TEM), UV spectrascopy and X-ray diffraction (XRD). The biosensor showed maximum response within 5s at pH 8.0 in 0.05M sodium phosphate buffer and 37°C, when operated at 20mVs -1 . The biosensor had a detection limit of 0.25μM with a wide working range between 1μM-2500μM. The biosensor was employed for measurement of l-lactic acid level in plasma of apparently healthy and diseased persons. Analytical recovery of added lactic acid in plasma was 95.5%. Within- and between-batch coefficients of variations were 6.24% and 4.19% respectively. There was a good correlation (R 2 =0.97) between plasma lactate values as measured by standard enzymatic spectrophotometric method and the present biosensor. The working enzyme electrode was used 180 times over a period of 140 days, when stored at 4°C. Copyright © 2016. Published by Elsevier Inc.

Description and mineralogy of Tertiary volcanic ash partings and their relationship to coal seams, near Homer, Alaska

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reinink-Smith, L.M.

1985-04-01

Outcrops of Tertiary coal-bearing units in sea cliffs of the Kenai Peninsula provide an excellent study area for volcanic ash partings in coals. Twenty mid-to late-Miocene, 50-cm to 3-m thick coal seams exposed in the sea cliffs about 10 km west of Homer contain an average of 10 volcanic ash or lapilli tuff partings each. The bedding relationships of the coal with any one parting cannot be predicted, and the contacts of the partings with the coal range from very sharp to predominantly gradational. These bedding relationships provide clues about the surface on which the ashes fell and on whichmore » the coal was accumulating. For example, some ashes fell in standing water, others on irregular subaerial surfaces. The partings are in various stages of alteration to kaolinite and bentonite, and vary in thickness from a few millimeters to about 10 cm. The consistency and texture of the partings depend on the degree of alteration; the less altered partings display visible pumice fragments and euhedral feldspars, commonly within a finer grained matrix. Separate pumice fragments, excluding matrix, can also occur as partings in the coal. The more altered partings may be wet and plastic, or they may be well indurated claystones; the colors range from gray-yellow to dark brown. The indurated prints are more common in older part of the section. The coal seams may be capped by volcanic ash partings and are commonly underlain by a pencil shale of nonvolcanic origin.« less

Alternative and traditional assessments: Their comparative impact on students' attitudes and science learning outcomes. An exploratory study

NASA Astrophysics Data System (ADS)

Century, Daisy Nelson

This probing study focused on alternative and traditional assessments, their comparative impacts on students' attitudes and science learning outcomes. Four basic questions were asked: What type of science learning stemming from the instruction can best be assessed by the use of traditional paper-and pencil test? What type of science learning stemming from the instruction can best be assessed by the use of alternative assessment? What are the differences in the types of learning outcomes that can be assessed by the use of paper-pencil test and alternative assessment test? Is there a difference in students' attitude towards learning science when assessment of outcomes is by alternative assessment means compared to traditional means compared to traditional means? A mixed methodology involving quantitative and qualitative techniques was utilized. However, the study was essentially a case study. Quantitative data analysis included content achievement and attitude results, to which non-parametric statistics were applied. Analysis of qualitative data was done as a case study utilizing pre-set protocols resulting in a narrative summary style of report. These outcomes were combined in order to produce conclusions. This study revealed that the traditional method yielded more concrete cognitive content learning than did the alternative assessment. The alternative assessment yielded more psychomotor, cooperative learning and critical thinking skills. In both the alternative and the traditional methods the student's attitudes toward science were positive. There was no significant differences favoring either group. The quantitative findings of no statistically significant differences suggest that at a minimum there is no loss in the use of alternative assessment methods, in this instance, performance testing. Adding the results from the qualitative analysis to this suggests (1) that class groups were more satisfied when alternative methods were employed, and (2) that the two assessment methodologies are complementary to each other, and thus should probably be used together to produce maximum benefit.

Performance of a scanning pencil-beam spaceborne scatterometer for ocean wind measurements

NASA Technical Reports Server (NTRS)

Moore, R. K.; Kennett, R. G.; Fuk, K.

1988-01-01

Simulation results show that a scatterometer design using two pencil beams scanning at different incidence angles measures the near-surface oceanic winds from a satellite better under most conditions than previous designs. The return signals from the ocean surface are much stronger than those from the fan beams used previously. Performance on a polar-orbiting satellite is compared with that of a fan beam spaceborne scatterometer. A wider and continuous swath is covered. The improvement in performance is higher at low wind speeds, so it is particularly suitable for measuring the low-mean-speed tropical wind fields. Performance on a low altitude tropic-orbiting platform such as the Space Station is also shown.

Sporadic E movement followed with a pencil beam high frequency radar

NASA Astrophysics Data System (ADS)

From, W. R.

1983-12-01

Several types of sporadic E are observed using the 5.80 and 3.84-MHz Bribie Island pencil-beam high-frequency radar. Blanketing Es takes the form of large flat sheets with ripples in them. Non-blanketing Es is observed to be small clouds that drift across the field of view (40 deg). There is continuous gradation of sporadic E structure between these extremes. There are at least four different physical means by which sporadic E clouds may apparently move. It is concluded that non-blanketing sporadic E consists of separate clouds which follow the movement of the constructive interference between internal gravity waves rather than being blown by the background wind.

Inter-comparison of Dose Distributions Calculated by FLUKA, GEANT4, MCNP, and PHITS for Proton Therapy

NASA Astrophysics Data System (ADS)

Yang, Zi-Yi; Tsai, Pi-En; Lee, Shao-Chun; Liu, Yen-Chiang; Chen, Chin-Cheng; Sato, Tatsuhiko; Sheu, Rong-Jiun

2017-09-01

The dose distributions from proton pencil beam scanning were calculated by FLUKA, GEANT4, MCNP, and PHITS, in order to investigate their applicability in proton radiotherapy. The first studied case was the integrated depth dose curves (IDDCs), respectively from a 100 and a 226-MeV proton pencil beam impinging a water phantom. The calculated IDDCs agree with each other as long as each code employs 75 eV for the ionization potential of water. The second case considered a similar condition of the first case but with proton energies in a Gaussian distribution. The comparison to the measurement indicates the inter-code differences might not only due to different stopping power but also the nuclear physics models. How the physics parameter setting affect the computation time was also discussed. In the third case, the applicability of each code for pencil beam scanning was confirmed by delivering a uniform volumetric dose distribution based on the treatment plan, and the results showed general agreement between each codes, the treatment plan, and the measurement, except that some deviations were found in the penumbra region. This study has demonstrated that the selected codes are all capable of performing dose calculations for therapeutic scanning proton beams with proper physics settings.

Guanine oxidation signal enhancement in DNA via a polyacrylonitrile nanofiber-coated and cyclic voltammetry-treated pencil graphite electrode

NASA Astrophysics Data System (ADS)

Aladag Tanik, Nilay; Demirkan, Elif; Aykut, Yakup

2018-07-01

This study investigated the electrochemical detection of specific nucleic acid hybridization sequences using a nanofiber-coated pencil graphite biosensor. The biosensor was developed to detect Val66Met single point mutations in the brain-derived neurotrophic factor gene, which is frequently observed in neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and bipolar disorder. The oxidation signal of the most electroactive and stable DNA base, i.e., guanine, was used at approximately +1.0 V. Pencil graphite electrode (PGE) surfaces were coated with polyacrylonitrile nanofibers by electrospinning. Cyclic voltammetry was applied to the nanofiber-coated PGE to pretreat its surfaces. The application of cyclic voltammetry to the nanofiber-coated PGE surfaces before attaching the probe yielded a four fold increase in the oxidation signal for guanine compared with that using the untreated and uncoated PGE surface. The signal reductions were 70% for hybridization, 10% for non-complementary binding, and 14% for a single mismatch compared with the probe. The differences in full match, non-complementary, and mismatch binding indicated that the biosensor selectively detected the target, and that it was possible to determine hybridization in about 65 min. The detection limit was 0.19 μg/ml at a target concentration of 10 ppm.

The Balance-Scale Task Revisited: A Comparison of Statistical Models for Rule-Based and Information-Integration Theories of Proportional Reasoning

PubMed Central

Hofman, Abe D.; Visser, Ingmar; Jansen, Brenda R. J.; van der Maas, Han L. J.

2015-01-01

We propose and test three statistical models for the analysis of children’s responses to the balance scale task, a seminal task to study proportional reasoning. We use a latent class modelling approach to formulate a rule-based latent class model (RB LCM) following from a rule-based perspective on proportional reasoning and a new statistical model, the Weighted Sum Model, following from an information-integration approach. Moreover, a hybrid LCM using item covariates is proposed, combining aspects of both a rule-based and information-integration perspective. These models are applied to two different datasets, a standard paper-and-pencil test dataset (N = 779), and a dataset collected within an online learning environment that included direct feedback, time-pressure, and a reward system (N = 808). For the paper-and-pencil dataset the RB LCM resulted in the best fit, whereas for the online dataset the hybrid LCM provided the best fit. The standard paper-and-pencil dataset yielded more evidence for distinct solution rules than the online data set in which quantitative item characteristics are more prominent in determining responses. These results shed new light on the discussion on sequential rule-based and information-integration perspectives of cognitive development. PMID:26505905

Sub-second pencil beam dose calculation on GPU for adaptive proton therapy.

PubMed

da Silva, Joakim; Ansorge, Richard; Jena, Rajesh

2015-06-21

Although proton therapy delivered using scanned pencil beams has the potential to produce better dose conformity than conventional radiotherapy, the created dose distributions are more sensitive to anatomical changes and patient motion. Therefore, the introduction of adaptive treatment techniques where the dose can be monitored as it is being delivered is highly desirable. We present a GPU-based dose calculation engine relying on the widely used pencil beam algorithm, developed for on-line dose calculation. The calculation engine was implemented from scratch, with each step of the algorithm parallelized and adapted to run efficiently on the GPU architecture. To ensure fast calculation, it employs several application-specific modifications and simplifications, and a fast scatter-based implementation of the computationally expensive kernel superposition step. The calculation time for a skull base treatment plan using two beam directions was 0.22 s on an Nvidia Tesla K40 GPU, whereas a test case of a cubic target in water from the literature took 0.14 s to calculate. The accuracy of the patient dose distributions was assessed by calculating the γ-index with respect to a gold standard Monte Carlo simulation. The passing rates were 99.2% and 96.7%, respectively, for the 3%/3 mm and 2%/2 mm criteria, matching those produced by a clinical treatment planning system.

Power System Transient Diagnostics Based on Novel Traveling Wave Detection

NASA Astrophysics Data System (ADS)

Hamidi, Reza Jalilzadeh

Modern electrical power systems demand novel diagnostic approaches to enhancing the system resiliency by improving the state-of-the-art algorithms. The proliferation of high-voltage optical transducers and high time-resolution measurements provide opportunities to develop novel diagnostic methods of very fast transients in power systems. At the same time, emerging complex configuration, such as multi-terminal hybrid transmission systems, limits the applications of the traditional diagnostic methods, especially in fault location and health monitoring. The impedance-based fault-location methods are inefficient for cross-bounded cables, which are widely used for connection of offshore wind farms to the main grid. Thus, this dissertation first presents a novel traveling wave-based fault-location method for hybrid multi-terminal transmission systems. The proposed method utilizes time-synchronized high-sampling voltage measurements. The traveling wave arrival times (ATs) are detected by observation of the squares of wavelet transformation coefficients. Using the ATs, an over-determined set of linear equations are developed for noise reduction, and consequently, the faulty segment is determined based on the characteristics of the provided equation set. Then, the fault location is estimated. The accuracy and capabilities of the proposed fault location method are evaluated and also compared to the existing traveling-wave-based method for a wide range of fault parameters. In order to improve power systems stability, auto-reclosing (AR), single-phase auto-reclosing (SPAR), and adaptive single-phase auto-reclosing (ASPAR) methods have been developed with the final objectives of distinguishing between the transient and permanent faults to clear the transient faults without de-energization of the solid phases. However, the features of the electrical arcs (transient faults) are severely influenced by a number of random parameters, including the convection of the air and plasma, wind speed, air pressure, and humidity. Therefore, the dead-time (the de-energization duration of the faulty phase) is unpredictable. Accordingly, conservatively long dead-times are usually considered by protection engineers. However, if the exact arc distinction time is determined, the power system stability and quality will enhance. Therefore, a new method for detection of arc extinction times leading to a new ASPAR method utilizing power line carrier (PLC) signals is presented. The efficiency of the proposed ASPAR method is verified through simulations and compared with the existing ASPAR methods. High-sampling measurements are prone to be skewed by the environmental noises and analog-to-digital (A/D) converters quantization errors. Therefore noise-contaminated measurements are the major source of uncertainties and errors in the outcomes of traveling wave-based diagnostic applications. The existing AT-detection methods do not provide enough sensitivity and selectivity at the same time. Therefore, a new AT-detection method based on short-time matrix pencil (STMPM) is developed to accurately detect ATs of the traveling waves with low signal-to-noise (SNR) ratios. As STMPM is based on matrix algebra, it is a challenging to implement this new technique in microprocessor-based fault locators. Hence, a fully recursive and computationally efficient method based on adaptive discrete Kalman filter (ADKF) is introduced for AT-detection, which is proper for microprocessors and able to accomplish accurate AT-detection for online applications such as ultra-high-speed protection. Both proposed AT-detection methods are evaluated based on extensive simulation studies, and the superior outcomes are compared to the existing methods.

Irradiation Design for an Experimental Murine Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ballesteros-Zebadua, P.; Moreno-Jimenez, S.; Suarez-Campos, J. E.

2010-12-07

In radiotherapy and stereotactic radiosurgery, small animal experimental models are frequently used, since there are still a lot of unsolved questions about the biological and biochemical effects of ionizing radiation. This work presents a method for small-animal brain radiotherapy compatible with a dedicated 6MV Linac. This rodent model is focused on the research of the inflammatory effects produced by ionizing radiation in the brain. In this work comparisons between Pencil Beam and Monte Carlo techniques, were used in order to evaluate accuracy of the calculated dose using a commercial planning system. Challenges in this murine model are discussed.

The effect of lower body stabilization and different writing tools on writing biomechanics in children with cerebral palsy.

PubMed

Cheng, Hsin-Yi Kathy; Lien, Yueh-Ju; Yu, Yu-Chun; Ju, Yan-Ying; Pei, Yu-Cheng; Cheng, Chih-Hsiu; Wu, David Bin-Chia

2013-04-01

A high percentage of children with cerebral palsy (CP) have difficulty keeping up with the handwriting demands at school. Previous studies have addressed the effects of proper sitting and writing tool on writing performance, but less on body biomechanics. The aim of this study was to investigate the influence of lower body stabilization and pencil design on body biomechanics in children with CP. Fourteen children (12.31±4.13 years old) with CP were recruited for this study. A crossover repeated measures design was employed, with two independent variables: lower body stabilization (with/without) and pencil (regular/assigned grip height/biaxial). The writing task was to trace the Archimedean spiral mazes. Electromyography (EMG) of the upper extremity, the wrist flexion/extension movements, and the whole body photography were recorded to quantify the changes in posture and upper extremity biomechanics. Two-way repeated measures ANOVA was used for statistical analysis. No significant main effects were revealed in the EMG and wrist kinematics. The lower body stabilization significantly decreased the trunk lateral and forward deviations, and the visual focus-vertical angle. The biaxial pencil and the assigned grip height design significantly decreased the head, shoulder, trunk, and pelvic deviations compared with the regular design. The results indicated that the lower body positioning was effective in improving the trunk posture. A pencil with an assigned grip height or with a biaxial design could improve head, shoulder, trunk and pelvic alignment, but did not influence the muscle exertion of the upper extremity. This study could provide guidelines for parents, teachers and clinicians regarding the selection of writing tools and the knowledge of proper positioning for the children with handwriting difficulties. Further analyses can focus on the design, modification and clinical application of assitive sitting and writing devices for the use in children with handwriting difficulties. Copyright © 2013 Elsevier Ltd. All rights reserved.

Recommendations for dose calculations of lung cancer treatment plans treated with stereotactic ablative body radiotherapy (SABR)

NASA Astrophysics Data System (ADS)

Devpura, S.; Siddiqui, M. S.; Chen, D.; Liu, D.; Li, H.; Kumar, S.; Gordon, J.; Ajlouni, M.; Movsas, B.; Chetty, I. J.

2014-03-01

The purpose of this study was to systematically evaluate dose distributions computed with 5 different dose algorithms for patients with lung cancers treated using stereotactic ablative body radiotherapy (SABR). Treatment plans for 133 lung cancer patients, initially computed with a 1D-pencil beam (equivalent-path-length, EPL-1D) algorithm, were recalculated with 4 other algorithms commissioned for treatment planning, including 3-D pencil-beam (EPL-3D), anisotropic analytical algorithm (AAA), collapsed cone convolution superposition (CCC), and Monte Carlo (MC). The plan prescription dose was 48 Gy in 4 fractions normalized to the 95% isodose line. Tumors were classified according to location: peripheral tumors surrounded by lung (lung-island, N=39), peripheral tumors attached to the rib-cage or chest wall (lung-wall, N=44), and centrally-located tumors (lung-central, N=50). Relative to the EPL-1D algorithm, PTV D95 and mean dose values computed with the other 4 algorithms were lowest for "lung-island" tumors with smallest field sizes (3-5 cm). On the other hand, the smallest differences were noted for lung-central tumors treated with largest field widths (7-10 cm). Amongst all locations, dose distribution differences were most strongly correlated with tumor size for lung-island tumors. For most cases, convolution/superposition and MC algorithms were in good agreement. Mean lung dose (MLD) values computed with the EPL-1D algorithm were highly correlated with that of the other algorithms (correlation coefficient =0.99). The MLD values were found to be ~10% lower for small lung-island tumors with the model-based (conv/superposition and MC) vs. the correction-based (pencil-beam) algorithms with the model-based algorithms predicting greater low dose spread within the lungs. This study suggests that pencil beam algorithms should be avoided for lung SABR planning. For the most challenging cases, small tumors surrounded entirely by lung tissue (lung-island type), a Monte-Carlo-based algorithm may be warranted.

Neutrons in active proton therapy: Parameterization of dose and dose equivalent.

PubMed

Schneider, Uwe; Hälg, Roger A; Lomax, Tony

2017-06-01

One of the essential elements of an epidemiological study to decide if proton therapy may be associated with increased or decreased subsequent malignancies compared to photon therapy is an ability to estimate all doses to non-target tissues, including neutron dose. This work therefore aims to predict for patients using proton pencil beam scanning the spatially localized neutron doses and dose equivalents. The proton pencil beam of Gantry 1 at the Paul Scherrer Institute (PSI) was Monte Carlo simulated using GEANT. Based on the simulated neutron dose and neutron spectra an analytical mechanistic dose model was developed. The pencil beam algorithm used for treatment planning at PSI has been extended using the developed model in order to calculate the neutron component of the delivered dose distribution for each treated patient. The neutron dose was estimated for two patient example cases. The analytical neutron dose model represents the three-dimensional Monte Carlo simulated dose distribution up to 85cm from the proton pencil beam with a satisfying precision. The root mean square error between Monte Carlo simulation and model is largest for 138MeV protons and is 19% and 20% for dose and dose equivalent, respectively. The model was successfully integrated into the PSI treatment planning system. In average the neutron dose is increased by 10% or 65% when using 160MeV or 177MeV instead of 138MeV. For the neutron dose equivalent the increase is 8% and 57%. The presented neutron dose calculations allow for estimates of dose that can be used in subsequent epidemiological studies or, should the need arise, to estimate the neutron dose at any point where a subsequent secondary tumour may occur. It was found that the neutron dose to the patient is heavily increased with proton energy. Copyright © 2016. Published by Elsevier GmbH.

SU-E-T-202: Impact of Monte Carlo Dose Calculation Algorithm On Prostate SBRT Treatments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Venencia, C; Garrigo, E; Cardenas, J

2014-06-01

Purpose: The purpose of this work was to quantify the dosimetric impact of using Monte Carlo algorithm on pre calculated SBRT prostate treatment with pencil beam dose calculation algorithm. Methods: A 6MV photon beam produced by a Novalis TX (BrainLAB-Varian) linear accelerator equipped with HDMLC was used. Treatment plans were done using 9 fields with Iplanv4.5 (BrainLAB) and dynamic IMRT modality. Institutional SBRT protocol uses a total dose to the prostate of 40Gy in 5 fractions, every other day. Dose calculation is done by pencil beam (2mm dose resolution), heterogeneity correction and dose volume constraint (UCLA) for PTV D95%=40Gy andmore » D98%>39.2Gy, Rectum V20Gy<50%, V32Gy<20%, V36Gy<10% and V40Gy<5%, Bladder V20Gy<40% and V40Gy<10%, femoral heads V16Gy<5%, penile bulb V25Gy<3cc, urethra and overlap region between PTV and PRV Rectum Dmax<42Gy. 10 SBRT treatments plans were selected and recalculated using Monte Carlo with 2mm spatial resolution and mean variance of 2%. DVH comparisons between plans were done. Results: The average difference between PTV doses constraints were within 2%. However 3 plans have differences higher than 3% which does not meet the D98% criteria (>39.2Gy) and should have been renormalized. Dose volume constraint differences for rectum, bladder, femoral heads and penile bulb were les than 2% and within tolerances. Urethra region and overlapping between PTV and PRV Rectum shows increment of dose in all plans. The average difference for urethra region was 2.1% with a maximum of 7.8% and for the overlapping region 2.5% with a maximum of 8.7%. Conclusion: Monte Carlo dose calculation on dynamic IMRT treatments could affects on plan normalization. Dose increment in critical region of urethra and PTV overlapping region with PTV could have clinical consequences which need to be studied. The use of Monte Carlo dose calculation algorithm is limited because inverse planning dose optimization use only pencil beam.« less

SU-F-J-191: Dosimetric Evaluation of a Left Chestwall Patient Treated with a Compact Proton Pencil Beam Gantry Utilizing Daily Setup CBCT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maynard, M; Chen, K; Rosen, L

Purpose: To evaluate the robustness of the gradient technique for treating a multi-isocenter left chest wall patient with a compact proton pencil beam gantry. Both CBCT and stereoscopic imaging are used to facilitate daily treatment setup. Methods: To treat the elongated chest wall planning target volume (PTV) with the compact PBS system, a 28 fraction (5040 CcGE) treatment plan was created using two fields with gradient matching technique. Daily table shifts between treatment field isocenters were obtained from the record and verify system for each treatment fraction. Copies of the initial treatment plan were made for each fraction and themore » field isocenter coordinates for each plan copy were adjusted to reflect daily table shifts. Doses were re-calculated for each fraction, summed, and compared against the initial plan. Results: The table shifts (average and range) were 2.2 (−5.1–+3.9), 3.0 (−6.0–+4.0) and 3.0 (−10.1–+1.9) millimeters in the anterior-posterior, superior-inferior and right-left directions, respectively. Dose difference to the PTV, heart and ipsilateral lung were evaluated. The percentage of the PTV receiving the prescription dose decreased from 94.6% to 89.1%. The D95 of the PTV increased from 99.6% to 99.9%. The maximum dose in PTV increased from 106.6% to 109.2% and V105 increased from 1.0% to 16.5%. The V20 of the ipsilateral lung increased from 18.5% to 21.0%. The mean heart dose difference was negligible. Conclusion: Observed dose differences to lung and heart tissues due to daily setup variations remained acceptably low while maintaining sufficient dose coverage to the PTV. This initial case study demonstrates the robustness of the gradient technique to treat a large target, multi-isocenter plan with a compact proton pencil beam gantry equipped with CBCT and stereoscopic imaging modalities.« less

SU-E-CAMPUS-T-05: Validation of High-Resolution 3D Patient QA for Proton Pencil Beam Scanning and IMPT by Polymer Gel Dosimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cardin, A; Avery, S; Ding, X

2014-06-15

Purpose: Validation of high-resolution 3D patient QA for proton pencil beam scanning and IMPT by polymer gel dosimetry. Methods: Four BANG3Pro polymer gel dosimeters (manufactured by MGS Research Inc, Madison, CT) were used for patient QA at the Robert's Proton Therapy Center (RPTC, Philadelphia, PA). All dosimeters were sealed in identical thin-wall Pyrex glass spheres. Each dosimeter contained a set of markers for 3D registration purposes. The dosimeters were mounted in a consistent and reproducible manner using a custom build holder. Two proton pencil beam scanning plans were designed using Varian Eclipse™ treatment planning system: 1) A two-field intensity modulatedmore » proton therapy (IMPT) plan and 2) one single field uniform dose (SFUD) plan. The IMPT fields were evaluated as a composite plan and individual fields, the SFUD plan was delivered as a single field plan.Laser CT scanning was performed using the manufacturer's OCTOPUS-IQ axial transmission laser CT scanner using a 1 mm slice thickness. 3D registration, analysis, and OD/cm to absorbed dose calibrations were perfomed using DICOM RT-Dose and CT files, and software developed by the manufacturer. 3D delta index, a metric equivalent to the gamma tool, was used for dose comparison. Results: Very good agreement with single IMPT fields and with SFUD was obtained. Composite IMPT fields had a less satisfactory agreement. The single fields had 3D delta index passing rates (3% dose difference, 3 mm DTA) of 98.98% and 94.91%. The composite 3D delta index passing rate was 80.80%. The SFUD passing rate was 93.77%. Required shifts of the dose distributions were less than 4 mm. Conclusion: A formulation of the BANG3Pro polymer gel dosimeter, suitable for 3D QA of proton patient plans is established and validated. Likewise, the mailed QA analysis service provided by the manufacturer is a practical option when required resources are unavailable. We fully disclose that the subject of this research regards a production of MGS Research, Inc.« less

Sexual assault support services and community systems: understanding critical issues and needs in the LGBTQ community.

PubMed

Todahl, Jeffrey L; Linville, Deanna; Bustin, Amy; Wheeler, Jenna; Gau, Jeff

2009-08-01

Lesbian, gay, bisexual, transgender, and queer (LGBTQ) individuals encounter social conditions that create important considerations for LGBTQ sexual assault victims. This exploratory, mixed-methods study examines the relationship between community attitudes toward LGBTQ persons and associated community responses to LGBTQ sexual assault victims. An online and paper-and-pencil survey (n = 130) and four focus group interviews (n = 14) are analyzed using frequency distributions and grounded theory methods. The central theme that emerged in focus group interviews, titled "low community awareness and support for sexual violence in the LGBTQ community," was corroborated by survey participants. Participants' views of unique considerations for LGBTQ sexual assault victims are presented, including causal factors, consequences, and recommended strategies.

28 CFR 544.31 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... activities, social and cultural organizations, movies, and stage shows. Religious activities, psychological... any of the usual media (oils, pastels, crayons, pencils, inks, and charcoal). (d) Hobbycraft...

28 CFR 544.31 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... activities, social and cultural organizations, movies, and stage shows. Religious activities, psychological... any of the usual media (oils, pastels, crayons, pencils, inks, and charcoal). (d) Hobbycraft...

28 CFR 544.31 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... activities, social and cultural organizations, movies, and stage shows. Religious activities, psychological... any of the usual media (oils, pastels, crayons, pencils, inks, and charcoal). (d) Hobbycraft...

28 CFR 544.31 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... activities, social and cultural organizations, movies, and stage shows. Religious activities, psychological... any of the usual media (oils, pastels, crayons, pencils, inks, and charcoal). (d) Hobbycraft...

28 CFR 544.31 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... activities, social and cultural organizations, movies, and stage shows. Religious activities, psychological... any of the usual media (oils, pastels, crayons, pencils, inks, and charcoal). (d) Hobbycraft...

An ultrasensitive electrochemiluminescent sensor based on a pencil graphite electrode modified with CdS nanorods for detection of chlorogenic acid in honeysuckle.

PubMed

Zheng, Ruijuan; Zhong, Jianhai; Zhao, Chenhao; Lang, Xiaoling; Hu, Zhibiao; Luo, Jiangshui

2017-08-01

In this paper, a novel and ultrasensitive electrochemiluminescent sensor employing a solvothermal-synthesized CdS nanorod-modified pencil graphite electrode (CdS/PGE) for the determination of chlorogenic acid (CA) is fabricated. In the first step, the PGE surface is modified using CdS nanorods. In the next step, the developed electrode is used to detect CA using a electrochemiluminescent (ECL) technique, in which potassium persulfate (K 2 S 2 O 8 ) served as a co-reactant. The possible ECL mechanism is investigated, and the influences of pH and cyclic voltammetric scanning rate on the signal response are studied. The ECL intensity decreases quantitatively in relation to the concentration of the target molecule. Under optimized conditions, the linear correlation between the quenched ECL intensity and the logarithm of CA concentration is observed in the range from 2 × 10 -9 to 8 × 10 -7  mol L -1 with a limit of detection of 1 × 10 -9  mol L -1 . This proposed method is applied to the analysis of CA in honeysuckle flower, giving recoveries of 99-107%. The experimental results demonstrate that this ECL sensor shows good stability and reproducibility. Copyright © 2016 John Wiley & Sons, Ltd.

Biosensing of glucose in flow injection analysis system based on glucose oxidase-quantum dot modified pencil graphite electrode.

PubMed

Sağlam, Özlem; Kızılkaya, Bayram; Uysal, Hüseyin; Dilgin, Yusuf

2016-01-15

A novel amperometric glucose biosensor was proposed in flow injection analysis (FIA) system using glucose oxidase (GOD) and Quantum dot (ZnS-CdS) modified Pencil Graphite Electrode (PGE). After ZnS-CdS film was electrochemically deposited onto PGE surface, GOD was immobilized on the surface of ZnS-CdS/PGE through crosslinking with chitosan (CT). A pair of well-defined reversible redox peak of GOD was observed at GOD/CT/ZnS-CdS/PGE based on enzyme electrode by direct electron transfer between the protein and electrode. Further, obtained GOD/CT/ZnS-CdS/PGE offers a disposable, low cost, selective and sensitive electrochemical biosensing of glucose in FIA system based on the decrease of the electrocatalytic response of the reduced form of GOD to dissolved oxygen. Under optimum conditions (flow rate, 1.3mL min(-1); transmission tubing length, 10cm; injection volume, 100μL; and constant applied potential, -500mV vs. Ag/AgCl), the proposed method displayed a linear response to glucose in the range of 0.01-1.0mM with detection limit of 3.0µM. The results obtained from this study would provide the basis for further development of the biosensing using PGE based FIA systems. Copyright © 2015 Elsevier B.V. All rights reserved.

Designing an audio computer-assisted self-interview (ACASI) system in a multisite trial: a brief report.

PubMed

2008-09-01

To describe the advantages and limitations of an audio computer-assisted self-interview (ACASI) system in a multisite trial with African American couples and to present the steps in designing, testing, and implementing a system. The ACASI system evolved from a paper and pencil interview that was pilot tested. Based on this initial work, the paper and pencil interview was translated into storyboards that were the basis of the development of ACASI system. Storyboards consisted of 1 page per question and provided the programmers with the test of the question, valid responses, and any instructions that were to be read to the participants. Storyboards were further translated into flow diagrams representing each module of the survey and illustrating the skip patterns used to navigate a participant through the survey. Provisions were also made to insert a face-to-face interview, into the ACASI assessment process, to elicit sexual abuse history data, which typically requires specially trained data collectors with active listening skills to help participants reframe and coordinate times, places and, emotionally difficult memories. The ACASI was successfully developed and implemented in the main trial. During an exit interview, respondents indicated that they liked using the ACASI and indicating that they favored it as the method to answer questions. It is feasible to implement an ACASI system in a multisite study in a timely and efficient way.

A review of the matrix-exponential formalism in radiative transfer

NASA Astrophysics Data System (ADS)

Efremenko, Dmitry S.; Molina García, Víctor; Gimeno García, Sebastián; Doicu, Adrian

2017-07-01

This paper outlines the matrix exponential description of radiative transfer. The eigendecomposition method which serves as a basis for computing the matrix exponential and for representing the solution in a discrete ordinate setting is considered. The mathematical equivalence of the discrete ordinate method, the matrix operator method, and the matrix Riccati equations method is proved rigorously by means of the matrix exponential formalism. For optically thin layers, approximate solution methods relying on the Padé and Taylor series approximations to the matrix exponential, as well as on the matrix Riccati equations, are presented. For optically thick layers, the asymptotic theory with higher-order corrections is derived, and parameterizations of the asymptotic functions and constants for a water-cloud model with a Gamma size distribution are obtained.

Finite element Compton tomography

NASA Astrophysics Data System (ADS)

Jannson, Tomasz; Amouzou, Pauline; Menon, Naresh; Gertsenshteyn, Michael

2007-09-01

In this paper a new approach to 3D Compton imaging is presented, based on a kind of finite element (FE) analysis. A window for X-ray incoherent scattering (or Compton scattering) attenuation coefficients is identified for breast cancer diagnosis, for hard X-ray photon energy of 100-300 keV. The point-by-point power/energy budget is computed, based on a 2D array of X-ray pencil beams, scanned vertically. The acceptable medical doses are also computed. The proposed finite element tomography (FET) can be an alternative to X-ray mammography, tomography, and tomosynthesis. In experiments, 100 keV (on average) X-ray photons are applied, and a new type of pencil beam collimation, based on a Lobster-Eye Lens (LEL), is proposed.

Gender differences in mental rotation across adulthood.

PubMed

Jansen, Petra; Heil, Martin

2010-01-01

Although gender differences in mental rotation in younger adults are prominent in paper-pencil tests as well as in chronometric tests with polygons as stimuli, less is known about this topic in the older age ranges. Therefore, performance was assessed with the Mental Rotation Test (MRT) paper-pencil test as well as with a computer-based two-stimulus same-different task with polygons in a sample of 150 adults divided into three age groups, 20-30, 40-50, and 60-70 years. Performance decreased with age, and men outperformed women in all age groups. The gender effect decreased with age in the MRT, possibly due to a floor effect. Gender differences remained constant across age, however, in the error rates of the computer-based task.

A review of critical in-flight events research methodology

NASA Technical Reports Server (NTRS)

Giffin, W. C.; Rockwell, T. H.; Smith, P. E.

1985-01-01

Pilot's cognitive responses to critical in-flight events (CIFE's) were investigated, using pilots, who had on the average about 2540 flight hours each, in four experiments: (1) full-mission simulation in a general aviation trainer, (2) paper and pencil CIFE tests, (3) interactive computer-aided scenario testing, and (4) verbal protocols in fault diagnosis tasks. The results of both computer and paper and pencil tests showed only 50 percent efficiency in correct diagnosis of critical events. The efficiency in arriving at a diagnosis was also low: over 20 inquiries were made for 21 percent of the scenarios diagnosed. The information-seeking pattern was random, with frequent retracing over old inquiries. The measures for developing improved cognitive skills for CIFE's are discussed.

Simple Pencil-and-Paper Notation for Representing Electrical Charge States

NASA Astrophysics Data System (ADS)

Morse, Robert A.

2017-11-01

In Benjamin Franklin's one fluid theory of electrification, ordinary unelectrified matter consisted of a matrix of matter suffused with a certain amount of "electrical fluid." Electrical effects were due to an excess or deficit of electrical fluid, hence the terms positive and negative. Before the development of a modern view of the atom, diagrams showing charged objects would simply have "+" or "-" signs to indicate the charged state. As physicists we know how to interpret these diagrams and understand what they are telling us about the underlying atomic model of charging. However, novice students may not readily make the connection between the atomic model, in which a charged solid object either gains or loses electrons but does not gain or lose positive charges. Furthermore, when isolated objects become charged, the total number of electrons must be accounted for as charge is a conserved quantity. To really understand the changes that occur in charging by contact, conduction, or induction, it is useful for students to visually represent the processes in a way that emphasizes the atomicity of the processes, including the induced polarization of objects, and the requirement that charge be conserved.

SU-E-T-621: Planning Methodologies for Cancer of the Anal Canal: Comparing IMRT, Rapid Arc, and Pencil Beam Scanning Proton Beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGlade, J; Kassaee, A

2015-06-15

Purpose: To evaluate planning methods for anal canal cancer and compare the results of 9-field Intensity Modulated Radiotherapy (IMRT), Volumetric Modulated Arc Therapy (Varian, RapidArc), and Proton Pencil Beam Scanning (PBS). Methods: We generated plans with IMRT, RapidArc (RA) and PBS for twenty patients for both initial phase including nodes and cone down phase of treatment using Eclipe (Varian). We evaluated the advantage of each technique for each phase. RA plans used 2 to 4 arcs and various collimator orientations. PBS used two posterior oblique fields. We evaluated the plans comparing dose volume histogram (DVH), locations of hot spots, andmore » PTV dose conformity. Results: Due to complex shape of target, for RA plans, multiple arcs (>2) are required to achieve optimal PTV conformity. When the PTV exceeds 15 cm in the superior-inferior direction, limitations of deliverability start to dominate. The PTV should be divided into a superior and an inferior structure. The optimization is performed with fixed jaws for each structure and collimator set to 90 degrees for the inferior PTV. Proton PBS plans show little advantage in small bowel sparing when treating the nodes. However, PBS plan reduces volumetric dose to the bladder at the cost of higher doses to the perineal skin. IMRT plans provide good target conformity, but they generate hot spots outside of the target volume. Conclusion: When using one planning technique for entire course of treatment, Multiple arc (>2) RA plans are better as compared to IMRT and PBS plans. When combining techniques, RA for the initial phase in combination with PBS for the cone down phase results in the most optimal plans.« less

SU-E-T-455: Characterization of 3D Printed Materials for Proton Beam Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zou, W; Siderits, R; McKenna, M

2014-06-01

Purpose: The widespread availability of low cost 3D printing technologies provides an alternative fabrication method for customized proton range modifying accessories such as compensators and boluses. However the material properties of the printed object are dependent on the printing technology used. In order to facilitate the application of 3D printing in proton therapy, this study investigated the stopping power of several printed materials using both proton pencil beam measurements and Monte Carlo simulations. Methods: Five 3–4 cm cubes fabricated using three 3D printing technologies (selective laser sintering, fused-deposition modeling and stereolithography) from five printers were investigated. The cubes were scannedmore » on a CT scanner and the depth dose curves for a mono-energetic pencil beam passing through the material were measured using a large parallel plate ion chamber in a water tank. Each cube was measured from two directions (perpendicular and parallel to printing plane) to evaluate the effects of the anisotropic material layout. The results were compared with GEANT4 Monte Carlo simulation using the manufacturer specified material density and chemical composition data. Results: Compared with water, the differences from the range pull back by the printed blocks varied and corresponded well with the material CT Hounsfield unit. The measurement results were in agreement with Monte Carlo simulation. However, depending on the technology, inhomogeneity existed in the printed cubes evidenced from CT images. The effect of such inhomogeneity on the proton beam is to be investigated. Conclusion: Printed blocks by three different 3D printing technologies were characterized for proton beam with measurements and Monte Carlo simulation. The effects of the printing technologies in proton range and stopping power were studied. The derived results can be applied when specific devices are used in proton radiotherapy.« less

High performance ultrasonic field simulation on complex geometries

NASA Astrophysics Data System (ADS)

Chouh, H.; Rougeron, G.; Chatillon, S.; Iehl, J. C.; Farrugia, J. P.; Ostromoukhov, V.

2016-02-01

Ultrasonic field simulation is a key ingredient for the design of new testing methods as well as a crucial step for NDT inspection simulation. As presented in a previous paper [1], CEA-LIST has worked on the acceleration of these simulations focusing on simple geometries (planar interfaces, isotropic materials). In this context, significant accelerations were achieved on multicore processors and GPUs (Graphics Processing Units), bringing the execution time of realistic computations in the 0.1 s range. In this paper, we present recent works that aim at similar performances on a wider range of configurations. We adapted the physical model used by the CIVA platform to design and implement a new algorithm providing a fast ultrasonic field simulation that yields nearly interactive results for complex cases. The improvements over the CIVA pencil-tracing method include adaptive strategies for pencil subdivisions to achieve a good refinement of the sensor geometry while keeping a reasonable number of ray-tracing operations. Also, interpolation of the times of flight was used to avoid time consuming computations in the impulse response reconstruction stage. To achieve the best performance, our algorithm runs on multi-core superscalar CPUs and uses high performance specialized libraries such as Intel Embree for ray-tracing, Intel MKL for signal processing and Intel TBB for parallelization. We validated the simulation results by comparing them to the ones produced by CIVA on identical test configurations including mono-element and multiple-element transducers, homogeneous, meshed 3D CAD specimens, isotropic and anisotropic materials and wave paths that can involve several interactions with interfaces. We show performance results on complete simulations that achieve computation times in the 1s range.

Efficient sparse matrix-matrix multiplication for computing periodic responses by shooting method on Intel Xeon Phi

NASA Astrophysics Data System (ADS)

Stoykov, S.; Atanassov, E.; Margenov, S.

2016-10-01

Many of the scientific applications involve sparse or dense matrix operations, such as solving linear systems, matrix-matrix products, eigensolvers, etc. In what concerns structural nonlinear dynamics, the computations of periodic responses and the determination of stability of the solution are of primary interest. Shooting method iswidely used for obtaining periodic responses of nonlinear systems. The method involves simultaneously operations with sparse and dense matrices. One of the computationally expensive operations in the method is multiplication of sparse by dense matrices. In the current work, a new algorithm for sparse matrix by dense matrix products is presented. The algorithm takes into account the structure of the sparse matrix, which is obtained by space discretization of the nonlinear Mindlin's plate equation of motion by the finite element method. The algorithm is developed to use the vector engine of Intel Xeon Phi coprocessors. It is compared with the standard sparse matrix by dense matrix algorithm and the one developed by Intel MKL and it is shown that by considering the properties of the sparse matrix better algorithms can be developed.

Method of forming a ceramic matrix composite and a ceramic matrix component

DOE Office of Scientific and Technical Information (OSTI.GOV)

de Diego, Peter; Zhang, James

A method of forming a ceramic matrix composite component includes providing a formed ceramic member having a cavity, filling at least a portion of the cavity with a ceramic foam. The ceramic foam is deposited on a barrier layer covering at least one internal passage of the cavity. The method includes processing the formed ceramic member and ceramic foam to obtain a ceramic matrix composite component. Also provided is a method of forming a ceramic matrix composite blade and a ceramic matrix composite component.

MO-F-CAMPUS-I-04: Characterization of Fan Beam Coded Aperture Coherent Scatter Spectral Imaging Methods for Differentiation of Normal and Neoplastic Breast Structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morris, R; Albanese, K; Lakshmanan, M

Purpose: This study intends to characterize the spectral and spatial resolution limits of various fan beam geometries for differentiation of normal and neoplastic breast structures via coded aperture coherent scatter spectral imaging techniques. In previous studies, pencil beam raster scanning methods using coherent scatter computed tomography and selected volume tomography have yielded excellent results for tumor discrimination. However, these methods don’t readily conform to clinical constraints; primarily prolonged scan times and excessive dose to the patient. Here, we refine a fan beam coded aperture coherent scatter imaging system to characterize the tradeoffs between dose, scan time and image quality formore » breast tumor discrimination. Methods: An X-ray tube (125kVp, 400mAs) illuminated the sample with collimated fan beams of varying widths (3mm to 25mm). Scatter data was collected via two linear-array energy-sensitive detectors oriented parallel and perpendicular to the beam plane. An iterative reconstruction algorithm yields images of the sample’s spatial distribution and respective spectral data for each location. To model in-vivo tumor analysis, surgically resected breast tumor samples were used in conjunction with lard, which has a form factor comparable to adipose (fat). Results: Quantitative analysis with current setup geometry indicated optimal performance for beams up to 10mm wide, with wider beams producing poorer spatial resolution. Scan time for a fixed volume was reduced by a factor of 6 when scanned with a 10mm fan beam compared to a 1.5mm pencil beam. Conclusion: The study demonstrates the utility of fan beam coherent scatter spectral imaging for differentiation of normal and neoplastic breast tissues has successfully reduced dose and scan times whilst sufficiently preserving spectral and spatial resolution. Future work to alter the coded aperture and detector geometries could potentially allow the use of even wider fans, thereby making coded aperture coherent scatter imaging a clinically viable method for breast cancer detection. United States Department of Homeland Security; Duke University Medical Center - Department of Radiology; Carl E Ravin Advanced Imaging Laboratories; Duke University Medical Physics Graduate Program.« less

Cosmic Microwave Background Mapmaking with a Messenger Field

NASA Astrophysics Data System (ADS)

Huffenberger, Kevin M.; Næss, Sigurd K.

2018-01-01

We apply a messenger field method to solve the linear minimum-variance mapmaking equation in the context of Cosmic Microwave Background (CMB) observations. In simulations, the method produces sky maps that converge significantly faster than those from a conjugate gradient descent algorithm with a diagonal preconditioner, even though the computational cost per iteration is similar. The messenger method recovers large scales in the map better than conjugate gradient descent, and yields a lower overall χ2. In the single, pencil beam approximation, each iteration of the messenger mapmaking procedure produces an unbiased map, and the iterations become more optimal as they proceed. A variant of the method can handle differential data or perform deconvolution mapmaking. The messenger method requires no preconditioner, but a high-quality solution needs a cooling parameter to control the convergence. We study the convergence properties of this new method and discuss how the algorithm is feasible for the large data sets of current and future CMB experiments.

Matrix completion by deep matrix factorization.

PubMed

Fan, Jicong; Cheng, Jieyu

2018-02-01

Conventional methods of matrix completion are linear methods that are not effective in handling data of nonlinear structures. Recently a few researchers attempted to incorporate nonlinear techniques into matrix completion but there still exists considerable limitations. In this paper, a novel method called deep matrix factorization (DMF) is proposed for nonlinear matrix completion. Different from conventional matrix completion methods that are based on linear latent variable models, DMF is on the basis of a nonlinear latent variable model. DMF is formulated as a deep-structure neural network, in which the inputs are the low-dimensional unknown latent variables and the outputs are the partially observed variables. In DMF, the inputs and the parameters of the multilayer neural network are simultaneously optimized to minimize the reconstruction errors for the observed entries. Then the missing entries can be readily recovered by propagating the latent variables to the output layer. DMF is compared with state-of-the-art methods of linear and nonlinear matrix completion in the tasks of toy matrix completion, image inpainting and collaborative filtering. The experimental results verify that DMF is able to provide higher matrix completion accuracy than existing methods do and DMF is applicable to large matrices. Copyright © 2017 Elsevier Ltd. All rights reserved.

A solvent-free microbial-activated air cathode battery paper platform made with pencil-traced graphite electrodes.

PubMed

Lee, Seung Ho; Ban, Ju Yeon; Oh, Chung-Hun; Park, Hun-Kuk; Choi, Samjin

2016-06-23

We present the fabrication of an ultra-low cost, disposable, solvent-free air cathode all-paper microbial fuel cell (MFC) that does not utilize any chemical treatments. The anode and cathode were fabricated by depositing graphite particles by drawing them on paper with a pencil (four strokes). Hydrophobic parchment paper was used as a proton exchange membrane (PEM) to allow only H(+) to pass. Air cathode MFC technology, where O2 was used as an electron acceptor, was implemented on the paper platform. The bioelectric current was generated by an electrochemical process involving the redox couple of microbial-activated extracellular electron transferred electrons, PEM-passed H(+), and O2 in the cathode. A fully micro-integrated pencil-traced MFC showed a fast start-time, producing current within 10 s after injection of bacterial cells. A single miniaturized all-paper air cathode MFC generated a maximum potential of 300 mV and a maximum current of 11 μA during 100 min after a single injection of Shewanella oneidensis. The micro-fabricated solvent-free air cathode all-paper MFC generated a power of 2,270 nW (5.68 mW/m(2)). The proposed solvent-free air cathode paper-based MFC device could be used for environmentally-friendly energy storage as well as in single-use medical power supplies that use organic matter.

A solvent-free microbial-activated air cathode battery paper platform made with pencil-traced graphite electrodes

PubMed Central

Lee, Seung Ho; Ban, Ju Yeon; Oh, Chung-Hun; Park, Hun-Kuk; Choi, Samjin

2016-01-01

We present the fabrication of an ultra-low cost, disposable, solvent-free air cathode all-paper microbial fuel cell (MFC) that does not utilize any chemical treatments. The anode and cathode were fabricated by depositing graphite particles by drawing them on paper with a pencil (four strokes). Hydrophobic parchment paper was used as a proton exchange membrane (PEM) to allow only H+ to pass. Air cathode MFC technology, where O2 was used as an electron acceptor, was implemented on the paper platform. The bioelectric current was generated by an electrochemical process involving the redox couple of microbial-activated extracellular electron transferred electrons, PEM-passed H+, and O2 in the cathode. A fully micro-integrated pencil-traced MFC showed a fast start-time, producing current within 10 s after injection of bacterial cells. A single miniaturized all-paper air cathode MFC generated a maximum potential of 300 mV and a maximum current of 11 μA during 100 min after a single injection of Shewanella oneidensis. The micro-fabricated solvent-free air cathode all-paper MFC generated a power of 2,270 nW (5.68 mW/m2). The proposed solvent-free air cathode paper-based MFC device could be used for environmentally-friendly energy storage as well as in single-use medical power supplies that use organic matter. PMID:27333815

Pencil grasp and children's handwriting legibility during different-length writing tasks.

PubMed

Dennis, J L; Swinth, Y

2001-01-01

This study examined the influence ofpencil grasp on handwriting legibility during both short and long writing tasks in 46fourth-grade students who were typically developing. Matched samples were used to controlfor variability. Regular classroom writing assignments were scoredfor word and letter legibility, and scores were compared using a mixed repeated-measures analysis of variance design. The two independent variables were pencil grasp (dynamic tripod grasp vs. atypical grasp) and task length (short vs. long). A significant difference was found between the letter legibility scores on the short task and the letter legibility scores on the long task. Students' legibility was greater on the short task than on the long task across both grasp conditions. No significant difference was found in scores between students who used dynamic tripod grasps and those who used atypical grasps, nor was there a significant interaction between grasp and task length. No significant differences were found between word legibility scores. The results indicate that although the students in this study wrote more legibly on the short task than on the long task, the type of grasp they used did not affect their legibility. Because of the limited sample size, the results of this study should be interpreted cautiously. More research in handwriting performance and pencil grasp is needed to provide clear expectations and treatment options for students.

Using computer-assisted survey instruments instead of paper and pencil increased completeness of self-administered sexual behavior questionnaires.

PubMed

Spark, Simone; Lewis, Dyani; Vaisey, Alaina; Smyth, Eris; Wood, Anna; Temple-Smith, Meredith; Lorch, Rebecca; Guy, Rebecca; Hocking, Jane

2015-01-01

To compare the data quality, logistics, and cost of a self-administered sexual behavior questionnaire administered either using a computer-assisted survey instrument (CASI) or by paper and pencil in a primary care clinic. A self-administered sexual behavior questionnaire was administered to 16-29 year olds attending general practice. Questionnaires were administered by either paper and pencil (paper) or CASI. A personal digital assistant was used to self-administer the CASI. A total of 4,491 people completed the questionnaire, with 46.9% responses via CASI and 53.2% by paper. Completion of questions was greater for CASI than for paper for sexual behavior questions: number of sexual partners [odds ratio (OR), 6.85; 95% confidence interval (CI): 3.32, 14.11] and ever having had sex with a person of the same gender (OR, 2.89; 95% CI: 1.52, 5.49). The median number of questions answered was higher for CASI than for paper (17.6 vs. 17.2; P < 0.01). CASI was cheaper to run at $8.18 per questionnaire compared with $11.83 for paper. Electronic devices using CASI are a tool that can increase participants' questionnaire responses and deliver more complete data for a sexual behavior questionnaire in primary care clinics. Copyright © 2015 Elsevier Inc. All rights reserved.

Sub-second pencil beam dose calculation on GPU for adaptive proton therapy

NASA Astrophysics Data System (ADS)

da Silva, Joakim; Ansorge, Richard; Jena, Rajesh

2015-06-01

Although proton therapy delivered using scanned pencil beams has the potential to produce better dose conformity than conventional radiotherapy, the created dose distributions are more sensitive to anatomical changes and patient motion. Therefore, the introduction of adaptive treatment techniques where the dose can be monitored as it is being delivered is highly desirable. We present a GPU-based dose calculation engine relying on the widely used pencil beam algorithm, developed for on-line dose calculation. The calculation engine was implemented from scratch, with each step of the algorithm parallelized and adapted to run efficiently on the GPU architecture. To ensure fast calculation, it employs several application-specific modifications and simplifications, and a fast scatter-based implementation of the computationally expensive kernel superposition step. The calculation time for a skull base treatment plan using two beam directions was 0.22 s on an Nvidia Tesla K40 GPU, whereas a test case of a cubic target in water from the literature took 0.14 s to calculate. The accuracy of the patient dose distributions was assessed by calculating the γ-index with respect to a gold standard Monte Carlo simulation. The passing rates were 99.2% and 96.7%, respectively, for the 3%/3 mm and 2%/2 mm criteria, matching those produced by a clinical treatment planning system.

Construction of mathematical knowledge using graphic calculators (CAS) in the mathematics classroom

NASA Astrophysics Data System (ADS)

Hitt, Fernando

2011-09-01

Mathematics education researchers are asking themselves about why technology has impacted heavily on the social environment and not in the mathematics classroom. The use of technology in the mathematics classroom has not had the expected impact, as it has been its use in everyday life (i.e. cell phone). What about teachers' opinions? Mathematics teachers can be divided into three categories: those with a boundless overflow (enthusiasm) who want to use the technology without worrying much about the construction of mathematical concepts, those who reject outright the use of technology because they think that their use inhibits the development of mathematical skills and others that reflect on the balance that must exist between paper-pencil activities and use of technology. The mathematics teacher, by not having clear examples that support this last option about the balance of paper-pencil activities and technology, opt for one of the extreme positions outlined above. In this article, we show the results of research on a methodology based on collaborative learning (ACODESA) in the training of mathematics teachers in secondary schools and implementation of activities in an environment of paper-pencil and CAS in the mathematics classroom. We also note that with the development of technology on the use of electronic tablets and interactive whiteboards, these activities will take on greater momentum in the near future.

Cyberfaking: I can, so I will? Intentions to fake in online psychological testing.

PubMed

Grieve, Rachel; Elliott, Jade

2013-05-01

The aim of this study was to investigate whether intentions to fake online (cyberfaking) or in pencil-and-paper psychological testing differ. Participants (N=154) completed online questionnaires measuring attitudes toward faking, perceived behavioral control over faking, subjective norms regarding faking, and intentions to fake in future psychological assessment, with online and pencil-and-paper test administration scenarios compared. Participants showed similar intentions toward cyberfaking and faking in pencil-and-paper testing. However, participants held more positive attitudes toward cyberfaking than faking offline, greater perceived behavioral control over cyberfaking than offline faking, and more favorable subjective norms toward cyberfaking compared to offline faking. Analysis via multiple regression revealed that more positive attitudes toward cyberfaking, greater perceived behavioral control over cyberfaking, and more favorable subjective norms regarding cyberfaking were significantly related to the intention to cyberfake. In addition, more positive attitudes toward faking offline and greater perceived behavioral control over faking offline were significantly related to the intention to fake in offline tests. Overall, results indicated a similar pattern of relationship in the prediction of intentions to engage in faking regardless of the test administration modality scenario. Subjective norm, however, was not a significant predictor for faking offline. Future research could aim to include a behavioral faking outcome measure, as well as examine intentions to cyberfake in specific scenarios (for example, faking good or faking bad).

A solvent-free microbial-activated air cathode battery paper platform made with pencil-traced graphite electrodes

NASA Astrophysics Data System (ADS)

Lee, Seung Ho; Ban, Ju Yeon; Oh, Chung-Hun; Park, Hun-Kuk; Choi, Samjin

2016-06-01

We present the fabrication of an ultra-low cost, disposable, solvent-free air cathode all-paper microbial fuel cell (MFC) that does not utilize any chemical treatments. The anode and cathode were fabricated by depositing graphite particles by drawing them on paper with a pencil (four strokes). Hydrophobic parchment paper was used as a proton exchange membrane (PEM) to allow only H+ to pass. Air cathode MFC technology, where O2 was used as an electron acceptor, was implemented on the paper platform. The bioelectric current was generated by an electrochemical process involving the redox couple of microbial-activated extracellular electron transferred electrons, PEM-passed H+, and O2 in the cathode. A fully micro-integrated pencil-traced MFC showed a fast start-time, producing current within 10 s after injection of bacterial cells. A single miniaturized all-paper air cathode MFC generated a maximum potential of 300 mV and a maximum current of 11 μA during 100 min after a single injection of Shewanella oneidensis. The micro-fabricated solvent-free air cathode all-paper MFC generated a power of 2,270 nW (5.68 mW/m2). The proposed solvent-free air cathode paper-based MFC device could be used for environmentally-friendly energy storage as well as in single-use medical power supplies that use organic matter.

Development of a golden beam data set for the commissioning of a proton double-scattering system in a pencil-beam dose calculation algorithm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Slopsema, R. L., E-mail: rslopsema@floridaproton.org; Flampouri, S.; Yeung, D.

2014-09-15

Purpose: The purpose of this investigation is to determine if a single set of beam data, described by a minimal set of equations and fitting variables, can be used to commission different installations of a proton double-scattering system in a commercial pencil-beam dose calculation algorithm. Methods: The beam model parameters required to commission the pencil-beam dose calculation algorithm (virtual and effective SAD, effective source size, and pristine-peak energy spread) are determined for a commercial double-scattering system. These parameters are measured in a first room and parameterized as function of proton energy and nozzle settings by fitting four analytical equations tomore » the measured data. The combination of these equations and fitting values constitutes the golden beam data (GBD). To determine the variation in dose delivery between installations, the same dosimetric properties are measured in two additional rooms at the same facility, as well as in a single room at another facility. The difference between the room-specific measurements and the GBD is evaluated against tolerances that guarantee the 3D dose distribution in each of the rooms matches the GBD-based dose distribution within clinically reasonable limits. The pencil-beam treatment-planning algorithm is commissioned with the GBD. The three-dimensional dose distribution in water is evaluated in the four treatment rooms and compared to the treatment-planning calculated dose distribution. Results: The virtual and effective SAD measurements fall between 226 and 257 cm. The effective source size varies between 2.4 and 6.2 cm for the large-field options, and 1.0 and 2.0 cm for the small-field options. The pristine-peak energy spread decreases from 1.05% at the lowest range to 0.6% at the highest. The virtual SAD as well as the effective source size can be accurately described by a linear relationship as function of the inverse of the residual energy. An additional linear correction term as function of RM-step thickness is required for accurate parameterization of the effective SAD. The GBD energy spread is given by a linear function of the exponential of the beam energy. Except for a few outliers, the measured parameters match the GBD within the specified tolerances in all of the four rooms investigated. For a SOBP field with a range of 15 g/cm{sup 2} and an air gap of 25 cm, the maximum difference in the 80%–20% lateral penumbra between the GBD-commissioned treatment-planning system and measurements in any of the four rooms is 0.5 mm. Conclusions: The beam model parameters of the double-scattering system can be parameterized with a limited set of equations and parameters. This GBD closely matches the measured dosimetric properties in four different rooms.« less

Key-Generation Algorithms for Linear Piece In Hand Matrix Method

NASA Astrophysics Data System (ADS)

Tadaki, Kohtaro; Tsujii, Shigeo

The linear Piece In Hand (PH, for short) matrix method with random variables was proposed in our former work. It is a general prescription which can be applicable to any type of multivariate public-key cryptosystems for the purpose of enhancing their security. Actually, we showed, in an experimental manner, that the linear PH matrix method with random variables can certainly enhance the security of HFE against the Gröbner basis attack, where HFE is one of the major variants of multivariate public-key cryptosystems. In 1998 Patarin, Goubin, and Courtois introduced the plus method as a general prescription which aims to enhance the security of any given MPKC, just like the linear PH matrix method with random variables. In this paper we prove the equivalence between the plus method and the primitive linear PH matrix method, which is introduced by our previous work to explain the notion of the PH matrix method in general in an illustrative manner and not for a practical use to enhance the security of any given MPKC. Based on this equivalence, we show that the linear PH matrix method with random variables has the substantial advantage over the plus method with respect to the security enhancement. In the linear PH matrix method with random variables, the three matrices, including the PH matrix, play a central role in the secret-key and public-key. In this paper, we clarify how to generate these matrices and thus present two probabilistic polynomial-time algorithms to generate these matrices. In particular, the second one has a concise form, and is obtained as a byproduct of the proof of the equivalence between the plus method and the primitive linear PH matrix method.

Sparse subspace clustering for data with missing entries and high-rank matrix completion.

PubMed

Fan, Jicong; Chow, Tommy W S

2017-09-01

Many methods have recently been proposed for subspace clustering, but they are often unable to handle incomplete data because of missing entries. Using matrix completion methods to recover missing entries is a common way to solve the problem. Conventional matrix completion methods require that the matrix should be of low-rank intrinsically, but most matrices are of high-rank or even full-rank in practice, especially when the number of subspaces is large. In this paper, a new method called Sparse Representation with Missing Entries and Matrix Completion is proposed to solve the problems of incomplete-data subspace clustering and high-rank matrix completion. The proposed algorithm alternately computes the matrix of sparse representation coefficients and recovers the missing entries of a data matrix. The proposed algorithm recovers missing entries through minimizing the representation coefficients, representation errors, and matrix rank. Thorough experimental study and comparative analysis based on synthetic data and natural images were conducted. The presented results demonstrate that the proposed algorithm is more effective in subspace clustering and matrix completion compared with other existing methods. Copyright © 2017 Elsevier Ltd. All rights reserved.

Gas sensors based on carbon nanoflake/tin oxide composites for ammonia detection.

PubMed

Lee, Soo-Keun; Chang, Daeic; Kim, Sang Wook

2014-03-15

Carbon nanoflake (CNFL) was obtained from graphite pencil by using the electrochemical method and the CNFL/SnO2 composite material assessed its potential as an ammonia gas sensor. A thin film resistive gas sensor using the composite material was manufactured by the drop casting method, and the sensor was evaluated to test in various ammonia concentrations and operating temperatures. Physical and chemical characteristics of the composite material were assessed using SEM, TEM, SAED, EDS and Raman spectroscopy. The composite material having 10% of SnO2 showed 3 times higher sensor response and better repeatability than the gas sensor using pristine SnO2 nano-particle at the optimal temperature of 350°C. Copyright © 2013 Elsevier B.V. All rights reserved.

Development of glucose biosensor based on reconstitution of glucose oxidase onto polymeric redox mediator coated pencil graphite electrodes.

PubMed

Dervisevic, Muamer; Cevik, Emre; Senel, Mehmet

2015-01-01

In this study, a novel glucose biosensor was fabricated by reconstitutional immobilization of glucose oxidase (GOx) onto a poly(glycidyl methacrylate-co-vinylferrocene) (poly(GMA-co-VFc)) film coated pencil graphite electrode (PGE). The amperometric current response of poly(GMA-co-VFc)-GOx to glucose is linear in the concentration range between 1 and 16mM (correlation coefficient of 0.9998) with a detection limit of 2.7μM (S/N=3). Experimental parameters were studied in detail and optimized, including the pH and temperature governing the analytical performance of the biosensor. The stability and reusability of the biosensor as well as its kinetic parameters have also been studied. Copyright © 2014 Elsevier Inc. All rights reserved.

Sequence-specific label-free nucleic acid biosensor for the detection of the hepatitis C virus genotype 1a using a disposable pencil graphite electrode.

PubMed

Donmez, Soner; Arslan, Fatma; Arslan, Halit

2016-05-01

In this paper, we demonstrate a simple, sensitive, inexpensive, disposable and label-free electrochemical nucleic acid biosensor for the detection of the hepatitis C virus genotype 1a (HCV1a). The nucleic acid biosensor was designed with the amino-linked inosine-substituted 20-mer probes, which were immobilized onto a disposable pencil graphite electrode (PGE) by covalent linking. The proposed nucleic acid biosensor was linear in the range of 0.05 and 0.75 μM, exhibiting a limit of detection of 54.9 nM. The single-stranded synthetic PCR product analogs of HCV1a were also detected with satisfactory results under optimal conditions, showing the potential application of this biosensor.

Generation of gas-phase ions from charged clusters: an important ionization step causing suppression of matrix and analyte ions in matrix-assisted laser desorption/ionization mass spectrometry.

PubMed

Lou, Xianwen; van Dongen, Joost L J; Milroy, Lech-Gustav; Meijer, E W

2016-12-30

Ionization in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a very complicated process. It has been reported that quaternary ammonium salts show extremely strong matrix and analyte suppression effects which cannot satisfactorily be explained by charge transfer reactions. Further investigation of the reasons causing these effects can be useful to improve our understanding of the MALDI process. The dried-droplet and modified thin-layer methods were used as sample preparation methods. In the dried-droplet method, analytes were co-crystallized with matrix, whereas in the modified thin-layer method analytes were deposited on the surface of matrix crystals. Model compounds, tetrabutylammonium iodide ([N(Bu) 4 ]I), cesium iodide (CsI), trihexylamine (THA) and polyethylene glycol 600 (PEG 600), were selected as the test analytes given their ability to generate exclusively pre-formed ions, protonated ions and metal ion adducts respectively in MALDI. The strong matrix suppression effect (MSE) observed using the dried-droplet method might disappear using the modified thin-layer method, which suggests that the incorporation of analytes in matrix crystals contributes to the MSE. By depositing analytes on the matrix surface instead of incorporating in the matrix crystals, the competition for evaporation/ionization from charged matrix/analyte clusters could be weakened resulting in reduced MSE. Further supporting evidence for this inference was found by studying the analyte suppression effect using the same two sample deposition methods. By comparing differences between the mass spectra obtained via the two sample preparation methods, we present evidence suggesting that the generation of gas-phase ions from charged matrix/analyte clusters may induce significant suppression of matrix and analyte ions. The results suggest that the generation of gas-phase ions from charged matrix/analyte clusters is an important ionization step in MALDI-MS. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

A robust method of computing finite difference coefficients based on Vandermonde matrix

NASA Astrophysics Data System (ADS)

Zhang, Yijie; Gao, Jinghuai; Peng, Jigen; Han, Weimin

2018-05-01

When the finite difference (FD) method is employed to simulate the wave propagation, high-order FD method is preferred in order to achieve better accuracy. However, if the order of FD scheme is high enough, the coefficient matrix of the formula for calculating finite difference coefficients is close to be singular. In this case, when the FD coefficients are computed by matrix inverse operator of MATLAB, inaccuracy can be produced. In order to overcome this problem, we have suggested an algorithm based on Vandermonde matrix in this paper. After specified mathematical transformation, the coefficient matrix is transformed into a Vandermonde matrix. Then the FD coefficients of high-order FD method can be computed by the algorithm of Vandermonde matrix, which prevents the inverse of the singular matrix. The dispersion analysis and numerical results of a homogeneous elastic model and a geophysical model of oil and gas reservoir demonstrate that the algorithm based on Vandermonde matrix has better accuracy compared with matrix inverse operator of MATLAB.

7 CFR 4285.25 - Authorized use of cooperative agreement funds.

Code of Federal Regulations, 2014 CFR

2014-01-01

... BUSINESS-COOPERATIVE SERVICE AND RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE COOPERATIVE AGREEMENTS... office supplies (such as paper, pens, pencils, and trade magazines) and postage needed for project...

7 CFR 4285.25 - Authorized use of cooperative agreement funds.

Code of Federal Regulations, 2013 CFR

2013-01-01

... BUSINESS-COOPERATIVE SERVICE AND RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE COOPERATIVE AGREEMENTS... office supplies (such as paper, pens, pencils, and trade magazines) and postage needed for project...

7 CFR 4285.25 - Authorized use of cooperative agreement funds.

Code of Federal Regulations, 2012 CFR

2012-01-01

... BUSINESS-COOPERATIVE SERVICE AND RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE COOPERATIVE AGREEMENTS... office supplies (such as paper, pens, pencils, and trade magazines) and postage needed for project...

7 CFR 4285.25 - Authorized use of cooperative agreement funds.

Code of Federal Regulations, 2011 CFR

2011-01-01

... BUSINESS-COOPERATIVE SERVICE AND RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE COOPERATIVE AGREEMENTS... office supplies (such as paper, pens, pencils, and trade magazines) and postage needed for project...

12 CFR 328.3 - Official advertising statement requirements.

Code of Federal Regulations, 2014 CFR

2014-01-01

... published by State or Federal law; (2) Insured depository institution supplies such as stationery (except... to, promotional items such as calendars, matchbooks, pens, pencils, and key chains; and (10...

Comparison of two Galerkin quadrature methods

DOE PAGES

Morel, Jim E.; Warsa, James; Franke, Brian C.; ...

2017-02-21

Here, we compare two methods for generating Galerkin quadratures. In method 1, the standard S N method is used to generate the moment-to-discrete matrix and the discrete-to-moment matrix is generated by inverting the moment-to-discrete matrix. This is a particular form of the original Galerkin quadrature method. In method 2, which we introduce here, the standard S N method is used to generate the discrete-to-moment matrix and the moment-to-discrete matrix is generated by inverting the discrete-to-moment matrix. With an N-point quadrature, method 1 has the advantage that it preserves N eigenvalues and N eigenvectors of the scattering operator in a pointwisemore » sense. With an N-point quadrature, method 2 has the advantage that it generates consistent angular moment equations from the corresponding S N equations while preserving N eigenvalues of the scattering operator. Our computational results indicate that these two methods are quite comparable for the test problem considered.« less

Comparison of two Galerkin quadrature methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morel, Jim E.; Warsa, James; Franke, Brian C.

Here, we compare two methods for generating Galerkin quadratures. In method 1, the standard S N method is used to generate the moment-to-discrete matrix and the discrete-to-moment matrix is generated by inverting the moment-to-discrete matrix. This is a particular form of the original Galerkin quadrature method. In method 2, which we introduce here, the standard S N method is used to generate the discrete-to-moment matrix and the moment-to-discrete matrix is generated by inverting the discrete-to-moment matrix. With an N-point quadrature, method 1 has the advantage that it preserves N eigenvalues and N eigenvectors of the scattering operator in a pointwisemore » sense. With an N-point quadrature, method 2 has the advantage that it generates consistent angular moment equations from the corresponding S N equations while preserving N eigenvalues of the scattering operator. Our computational results indicate that these two methods are quite comparable for the test problem considered.« less

Dark-field hyperspectral X-ray imaging

PubMed Central

Egan, Christopher K.; Jacques, Simon D. M.; Connolley, Thomas; Wilson, Matthew D.; Veale, Matthew C.; Seller, Paul; Cernik, Robert J.

2014-01-01

In recent times, there has been a drive to develop non-destructive X-ray imaging techniques that provide chemical or physical insight. To date, these methods have generally been limited; either requiring raster scanning of pencil beams, using narrow bandwidth radiation and/or limited to small samples. We have developed a novel full-field radiographic imaging technique that enables the entire physio-chemical state of an object to be imaged in a single snapshot. The method is sensitive to emitted and scattered radiation, using a spectral imaging detector and polychromatic hard X-radiation, making it particularly useful for studying large dense samples for materials science and engineering applications. The method and its extension to three-dimensional imaging is validated with a series of test objects and demonstrated to directly image the crystallographic preferred orientation and formed precipitates across an aluminium alloy friction stir weld section. PMID:24808753

Method of producing a hybrid matrix fiber composite

DOEpatents

Deteresa, Steven J [Livermore, CA; Lyon, Richard E [Absecon, NJ; Groves, Scott E [Brentwood, CA

2006-03-28

Hybrid matrix fiber composites having enhanced compressive performance as well as enhanced stiffness, toughness and durability suitable for compression-critical applications. The methods for producing the fiber composites using matrix hybridization. The hybrid matrix fiber composites comprised of two chemically or physically bonded matrix materials, whereas the first matrix materials are used to impregnate multi-filament fibers formed into ribbons and the second matrix material is placed around and between the fiber ribbons that are impregnated with the first matrix material and both matrix materials are cured and solidified.

Approximate method of variational Bayesian matrix factorization/completion with sparse prior

NASA Astrophysics Data System (ADS)

Kawasumi, Ryota; Takeda, Koujin

2018-05-01

We derive the analytical expression of a matrix factorization/completion solution by the variational Bayes method, under the assumption that the observed matrix is originally the product of low-rank, dense and sparse matrices with additive noise. We assume the prior of a sparse matrix is a Laplace distribution by taking matrix sparsity into consideration. Then we use several approximations for the derivation of a matrix factorization/completion solution. By our solution, we also numerically evaluate the performance of a sparse matrix reconstruction in matrix factorization, and completion of a missing matrix element in matrix completion.

The fast algorithm of spark in compressive sensing

NASA Astrophysics Data System (ADS)

Xie, Meihua; Yan, Fengxia

2017-01-01

Compressed Sensing (CS) is an advanced theory on signal sampling and reconstruction. In CS theory, the reconstruction condition of signal is an important theory problem, and spark is a good index to study this problem. But the computation of spark is NP hard. In this paper, we study the problem of computing spark. For some special matrixes, for example, the Gaussian random matrix and 0-1 random matrix, we obtain some conclusions. Furthermore, for Gaussian random matrix with fewer rows than columns, we prove that its spark equals to the number of its rows plus one with probability 1. For general matrix, two methods are given to compute its spark. One is the method of directly searching and the other is the method of dual-tree searching. By simulating 24 Gaussian random matrixes and 18 0-1 random matrixes, we tested the computation time of these two methods. Numerical results showed that the dual-tree searching method had higher efficiency than directly searching, especially for those matrixes which has as much as rows and columns.

The Game of Tri

ERIC Educational Resources Information Center

Haggard, Gary; Schonberger, Ann Koch

1977-01-01

The paper-and-pencil game "Tri" is described. The authors argue that students gain logical skills by playing the game, and that the game lends itself to the introduction of diverse mathematical ideas. (SD)

A sparse matrix-vector multiplication based algorithm for accurate density matrix computations on systems of millions of atoms

NASA Astrophysics Data System (ADS)

Ghale, Purnima; Johnson, Harley T.

2018-06-01

We present an efficient sparse matrix-vector (SpMV) based method to compute the density matrix P from a given Hamiltonian in electronic structure computations. Our method is a hybrid approach based on Chebyshev-Jackson approximation theory and matrix purification methods like the second order spectral projection purification (SP2). Recent methods to compute the density matrix scale as O(N) in the number of floating point operations but are accompanied by large memory and communication overhead, and they are based on iterative use of the sparse matrix-matrix multiplication kernel (SpGEMM), which is known to be computationally irregular. In addition to irregularity in the sparse Hamiltonian H, the nonzero structure of intermediate estimates of P depends on products of H and evolves over the course of computation. On the other hand, an expansion of the density matrix P in terms of Chebyshev polynomials is straightforward and SpMV based; however, the resulting density matrix may not satisfy the required constraints exactly. In this paper, we analyze the strengths and weaknesses of the Chebyshev-Jackson polynomials and the second order spectral projection purification (SP2) method, and propose to combine them so that the accurate density matrix can be computed using the SpMV computational kernel only, and without having to store the density matrix P. Our method accomplishes these objectives by using the Chebyshev polynomial estimate as the initial guess for SP2, which is followed by using sparse matrix-vector multiplications (SpMVs) to replicate the behavior of the SP2 algorithm for purification. We demonstrate the method on a tight-binding model system of an oxide material containing more than 3 million atoms. In addition, we also present the predicted behavior of our method when applied to near-metallic Hamiltonians with a wide energy spectrum.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thorne, N; Kassaee, A

Purpose: To develop an algorithm which can calculate the Full Width Half Maximum (FWHM) of a Proton Pencil Beam from a 2D dimensional ion chamber array (IBA Matrixx) with limited spatial resolution ( 7.6 mm inter chamber distance). The algorithm would allow beam FWHM measurements to be taken during daily QA without an appreciable time increase. Methods: Combinations of 147 MeV single spot beams were delivered onto an IBA Matrixx and concurrently on EBT3 films for a standard. Data were collected around the Bragg Peak region and evaluated by a custom MATLAB script based on our algorithm using a leastmore » squared analysis. A set of artificial data, modified with random noise, was also processed to test for robustness. Results: The Matlab script processed Matixx data shows acceptable agreement (within 5%) with film measurements with no single measurement differing by more than 1.8 mm. In cases where the spots show some degree of asymmetry, the algorithm is able to resolve the differences. The algorithm was able to process artificial data with noise up to 15% of the maximum value. Time assays of each measurement took less than 3 minutes to perform, indicating that such measurements may be efficiently added to daily QA treatment. Conclusion: The developed algorithm can be implemented in daily QA program for Proton Pencil Beam scanning beams (PBS) with Matrixx to extract spot size and position information. The developed algorithm may be extended to small field sizes in photon clinic.« less

Optimized Projection Matrix for Compressive Sensing

NASA Astrophysics Data System (ADS)

Xu, Jianping; Pi, Yiming; Cao, Zongjie

2010-12-01

Compressive sensing (CS) is mainly concerned with low-coherence pairs, since the number of samples needed to recover the signal is proportional to the mutual coherence between projection matrix and sparsifying matrix. Until now, papers on CS always assume the projection matrix to be a random matrix. In this paper, aiming at minimizing the mutual coherence, a method is proposed to optimize the projection matrix. This method is based on equiangular tight frame (ETF) design because an ETF has minimum coherence. It is impossible to solve the problem exactly because of the complexity. Therefore, an alternating minimization type method is used to find a feasible solution. The optimally designed projection matrix can further reduce the necessary number of samples for recovery or improve the recovery accuracy. The proposed method demonstrates better performance than conventional optimization methods, which brings benefits to both basis pursuit and orthogonal matching pursuit.

Adaptive intensity modulated radiotherapy for advanced prostate cancer

NASA Astrophysics Data System (ADS)

Ludlum, Erica Marie

The purpose of this research is to develop and evaluate improvements in intensity modulated radiotherapy (IMRT) for concurrent treatment of prostate and pelvic lymph nodes. The first objective is to decrease delivery time while maintaining treatment quality, and evaluate the effectiveness and efficiency of novel one-step optimization compared to conventional two-step optimization. Both planning methods are examined at multiple levels of complexity by comparing the number of beam apertures, or segments, the amount of radiation delivered as measured by monitor units (MUs), and delivery time. One-step optimization is demonstrated to simplify IMRT planning and reduce segments (from 160 to 40), MUs (from 911 to 746), and delivery time (from 22 to 7 min) with comparable plan quality. The second objective is to examine the capability of three commercial dose calculation engines employing different levels of accuracy and efficiency to handle high--Z materials, such as metallic hip prostheses, included in the treatment field. Pencil beam, convolution superposition, and Monte Carlo dose calculation engines are compared by examining the dose differences for patient plans with unilateral and bilateral hip prostheses, and for phantom plans with a metal insert for comparison with film measurements. Convolution superposition and Monte Carlo methods calculate doses that are 1.3% and 34.5% less than the pencil beam method, respectively. Film results demonstrate that Monte Carlo most closely represents actual radiation delivery, but none of the three engines accurately predict the dose distribution when high-Z heterogeneities exist in the treatment fields. The final objective is to improve the accuracy of IMRT delivery by accounting for independent organ motion during concurrent treatment of the prostate and pelvic lymph nodes. A leaf-shifting algorithm is developed to track daily prostate position without requiring online dose calculation. Compared to conventional methods of adjusting patient position, adjusting the multileaf collimator (MLC) leaves associated with the prostate in each segment significantly improves lymph node dose coverage (maintains 45 Gy compared to 42.7, 38.3, and 34.0 Gy for iso-shifts of 0.5, 1 and 1.5 cm). Altering the MLC portal shape is demonstrated as a new and effective solution to independent prostate movement during concurrent treatment.

TU-FG-BRB-04: A New Optimization Method for Pre-Treatment Patient-Specific Stopping-Power by Combining Proton Radiography and X-Ray CT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collins-Fekete, C; Centre Hospitalier University de Quebec, Quebec, QC; Mass General Hospital

Purpose: The relative stopping power (RSP) uncertainty is the largest contributor to the range uncertainty in proton therapy. The purpose of this work is to develop a robust and systematic method that yields accurate patient specific RSPs by combining pre-treatment X-ray CT and daily proton radiography. Methods: The method is formulated as a penalized least squares optimization (PLSO) problem min(|Ax-B|). The matrix A represents the cumulative path-length crossed in each material computed by calculating proton trajectories through the X-ray CT. The material RSPs are denoted by x and B is the pRad, expressed as water equivalent thickness. The equation ismore » solved using a convex-conic optimizer. Geant4 simulations were made to assess the feasibility of the method. RSP extracted from the Geant4 materials were used as a reference and the clinical HU-RSP curve as a comparison. The PLSO was first tested on a Gammex RMI-467 phantom. Then, anthropomorphic phantoms of the head, pelvis and lung were studied and resulting RSPs were evaluated. A pencil beam was generated in each phantom to evaluate the proton range accuracy achievable by using the optimized RSPs. Finally, experimental data of a pediatric head phantom (CIRS) were acquired using a recently completed experimental pCT scanner. Results: Numerical simulations showed precise RSP (<0.75%) for Gammex materials except low-density lung (LN-300) (1.2%). Accurate RSP have been obtained for the head (µ=−0.10%, 1.5σ=1.12%), lung (µ=−0.33, 1.5σ=1.02%) and pelvis anthropomorphic phantoms (µ=0.12, 1.5σ=0,99%). The range precision has been improved with an average R80 difference to the reference (µ±1.5σ) of −0.20±0.35%, −0.47±0.92% and −0.06±0.17% in the head, lung and pelvis phantoms respectively, compared to the 3.5% clinical margin. Experimental HU-RSP curve have been produced on the CIRS pediatric head. Conclusion: The proposed PLSO with prior knowledge X-ray CT shows promising potential (R80 σ<1.0% over all sites) to decrease the range uncertainty.« less

Aphasia vs. Apraxia

MedlinePlus

... tech system – Paper and pencil High-tech system – Computer program that produces voice output at keystroke Oral ... for Aphasia Actions Speak as Loud as Words Computers & Language Rehab From Singing to Speaking When the ...

Ear Injuries (For Parents)

MedlinePlus

... Inserting something into the ear. Things like a cotton swab, fingernail, or pencil can scratch the ear ... Never stick anything in their ears — not even cotton swabs or their fingers. Regular bathing should be ...

Preliminary Studies for a CBCT Imaging Protocol for Offline Organ Motion Analysis: Registration Software Validation and CTDI Measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Falco, Maria Daniela, E-mail: mdanielafalco@hotmail.co; Fontanarosa, Davide; Miceli, Roberto

2011-04-01

Cone-beam X-ray volumetric imaging in the treatment room, allows online correction of set-up errors and offline assessment of residual set-up errors and organ motion. In this study the registration algorithm of the X-ray volume imaging software (XVI, Elekta, Crawley, United Kingdom), which manages a commercial cone-beam computed tomography (CBCT)-based positioning system, has been tested using a homemade and an anthropomorphic phantom to: (1) assess its performance in detecting known translational and rotational set-up errors and (2) transfer the transformation matrix of its registrations into a commercial treatment planning system (TPS) for offline organ motion analysis. Furthermore, CBCT dose index hasmore » been measured for a particular site (prostate: 120 kV, 1028.8 mAs, approximately 640 frames) using a standard Perspex cylindrical body phantom (diameter 32 cm, length 15 cm) and a 10-cm-long pencil ionization chamber. We have found that known displacements were correctly calculated by the registration software to within 1.3 mm and 0.4{sup o}. For the anthropomorphic phantom, only translational displacements have been considered. Both studies have shown errors within the intrinsic uncertainty of our system for translational displacements (estimated as 0.87 mm) and rotational displacements (estimated as 0.22{sup o}). The resulting table translations proposed by the system to correct the displacements were also checked with portal images and found to place the isocenter of the plan on the linac isocenter within an error of 1 mm, which is the dimension of the spherical lead marker inserted at the center of the homemade phantom. The registration matrix translated into the TPS image fusion module correctly reproduced the alignment between planning CT scans and CBCT scans. Finally, measurements on the CBCT dose index indicate that CBCT acquisition delivers less dose than conventional CT scans and electronic portal imaging device portals. The registration software was found to be accurate, and its registration matrix can be easily translated into the TPS and a low dose is delivered to the patient during image acquisition. These results can help in designing imaging protocols for offline evaluations.« less

Comparison of matrix effects in HPLC-MS/MS and UPLC-MS/MS analysis of nine basic pharmaceuticals in surface waters.

PubMed

Van De Steene, Jet C; Lambert, Willy E

2008-05-01

When developing an LC-MS/MS-method matrix effects are a major issue. The effect of co-eluting compounds arising from the matrix can result in signal enhancement or suppression. During method development much attention should be paid to diminishing matrix effects as much as possible. The present work evaluates matrix effects from aqueous environmental samples in the simultaneous analysis of a group of 9 specific pharmaceuticals with HPLC-ESI/MS/MS and UPLC-ESI/MS/MS: flubendazole, propiconazole, pipamperone, cinnarizine, ketoconazole, miconazole, rabeprazole, itraconazole and domperidone. When HPLC-MS/MS is used, matrix effects are substantial and can not be compensated for with analogue internal standards. For different surface water samples different matrix effects are found. For accurate quantification the standard addition approach is necessary. Due to the better resolution and more narrow peaks in UPLC, analytes will co-elute less with interferences during ionisation, so matrix effects could be lower, or even eliminated. If matrix effects are eliminated with this technique, the standard addition method for quantification can be omitted and the overall method will be simplified. Results show that matrix effects are almost eliminated if internal standards (structural analogues) are used. Instead of the time-consuming and labour-intensive standard addition method, with UPLC the internal standardization can be used for quantification and the overall method is substantially simplified.

Fast Low-Rank Bayesian Matrix Completion With Hierarchical Gaussian Prior Models

NASA Astrophysics Data System (ADS)

Yang, Linxiao; Fang, Jun; Duan, Huiping; Li, Hongbin; Zeng, Bing

2018-06-01

The problem of low rank matrix completion is considered in this paper. To exploit the underlying low-rank structure of the data matrix, we propose a hierarchical Gaussian prior model, where columns of the low-rank matrix are assumed to follow a Gaussian distribution with zero mean and a common precision matrix, and a Wishart distribution is specified as a hyperprior over the precision matrix. We show that such a hierarchical Gaussian prior has the potential to encourage a low-rank solution. Based on the proposed hierarchical prior model, a variational Bayesian method is developed for matrix completion, where the generalized approximate massage passing (GAMP) technique is embedded into the variational Bayesian inference in order to circumvent cumbersome matrix inverse operations. Simulation results show that our proposed method demonstrates superiority over existing state-of-the-art matrix completion methods.

12 CFR 740.5 - Requirements for the official advertising statement.

Code of Federal Regulations, 2013 CFR

2013-01-01

... advertising statement: (1) Credit union supplies such as stationery (except when used for circular letters..., including but not limited to, promotional items such as calendars, matchbooks, pens, pencils, and key chains...

12 CFR 740.5 - Requirements for the official advertising statement.

Code of Federal Regulations, 2014 CFR

2014-01-01

... advertising statement: (1) Credit union supplies such as stationery (except when used for circular letters..., including but not limited to, promotional items such as calendars, matchbooks, pens, pencils, and key chains...

12 CFR 740.5 - Requirements for the official advertising statement.

Code of Federal Regulations, 2012 CFR

2012-01-01

... advertising statement: (1) Credit union supplies such as stationery (except when used for circular letters..., including but not limited to, promotional items such as calendars, matchbooks, pens, pencils, and key chains...

11 CFR 7.8 - Gifts, entertainment, and favors.

Code of Federal Regulations, 2010 CFR

2010-01-01

... persons concerned which are the motivating factors; (2) To the acceptance of food, refreshments, and... as pens, pencils, note pads, calendars; and (4) To the acceptance of loans from banks or other...

New Beam Scanning Device for Active Beam Delivery System (BDS) in Proton Therapy

NASA Astrophysics Data System (ADS)

Variale, V.; Mastromarco, M.; Colamaria, F.; Colella, D.

A new Beam Delivery System (BDS) has been studied in the framework of a new proton therapy project, called AMIDERHA. It is characterized by an active scanning system for target irradiation with a pencil beam. The project is based on the use of a Linac with variable final energy and the Robotized Patient Positioning System instead of the traditional gantry. As a consequence, in the active BDS of AMIDERHA a pencil beam scanning system with a relatively long Source to Axis Distance (SAD) can be used. In this contribution, the idea of using a unique new device capable of both horizontal and vertical beam scansion for the AMIDERHA active BDS will be presented and discussed. Furthermore, a preliminary design of that device will be shown, together with the results of simulations.

Pencil-like imaging spectrometer for bio-samples sensing.

PubMed

Cai, Fuhong; Wang, Dan; Zhu, Min; He, Sailing

2017-12-01

Spectrally-resolved imaging techniques are becoming central to the investigation of bio-samples. In this paper, we demonstrate the use of a WIFI-camera as a detection module to assemble a pencil-like imaging spectrometer, which weighs only 140 g and has a size of 3.1 cm in diameter and 15.5 cm in length. The spectrometer is standalone, and works wirelessly. A smartphone or network computer can serve as the data receiver and processor. The wavelength resolution of the spectrometer is about 17 nm, providing repeatable measurements of spatial two-dimensional images at various wavelengths for various bio-samples, including bananas, meat, and human hands. The detected spectral range is 400 nm - 675 nm and a white LED array lamp is selected as the light source. Based on the detected spectra, we can monitor the impacts of chlorophyll, myoglobin, and hemoglobin on bananas, pork, and human hands, respectively. For human hand scanning, a 3D spectral image data cube, which exhibits excellent signal to background noise ratio, can be obtained within 16 sec. We envisage that the adaptation of imaging spectrometer devices to the widely-accepted smartphone technology will help to carry out on-site studies in various applications. Besides, our pencil-like imaging spectrometer is cost-effective (<$300) and easy to assemble. This portable imaging spectrometer can facilitate the collection of large amounts of spectral image data. With the help of machine learning, we can realize object recognition based on spectral classification in the future.

Microbial fuel cell characterisation and evaluation of Lysinibacillus macroides MFC02 electrigenic capability.

PubMed

Uma Vanitha, Murugan; Natarajan, Muthusamy; Sridhar, Harikrishnamoorthy; Umamaheswari, Sankaran

2017-05-01

Microbial fuel cell (MFC) is the most prominent research field due to its capability to generate electricity by utilizing the renewable sources. In the present study, Two MFC designs namely, H type-Microbial fuel cell (HT-MFC) and U type-Microbial fuel cell (UT-MFC) were constructed based on standardized H shaped anode and cathode compartment as well as U shaped anode and cathode compartments, respectively. In order to lower the cost for MFC construction, Pencil graphite lead was used as electrode and salt agar as Proton exchange membrane. Results inferred that newly constructed UT-MFC showed high electron production when compared to the HT-MFC. UT-MFC displayed an output of about 377 ± 18.85 mV (millivolts); whereas HT-MFC rendered only 237 ± 11.85 mV (millivolts) of power generation, which might be due to the low internal resistance. By increasing the number of cathode in UT-MFC, power production was increased upto 313 ± 15.65 mV in Open circuit voltage (OCV). Electrogenic bacteria namely, Lysinibacillus macroides (Acc. No. KX011879) rendered enriched power generation. The attachment of bacteria as a biofilm on pencil graphite lead was analyzed using fluorescent microscope and Scanning Electron Microscope (SEM). Based on our findings, it was observed that UT-MFC has a tendency to produce high electron generation using pencil graphite lead as the electrode material.

Advanced proton beam dosimetry part II: Monte Carlo vs. pencil beam-based planning for lung cancer

PubMed Central

Maes, Dominic; Saini, Jatinder; Zeng, Jing; Rengan, Ramesh; Wong, Tony

2018-01-01

Background Proton pencil beam (PB) dose calculation algorithms have limited accuracy within heterogeneous tissues of lung cancer patients, which may be addressed by modern commercial Monte Carlo (MC) algorithms. We investigated clinical pencil beam scanning (PBS) dose differences between PB and MC-based treatment planning for lung cancer patients. Methods With IRB approval, a comparative dosimetric analysis between RayStation MC and PB dose engines was performed on ten patient plans. PBS gantry plans were generated using single-field optimization technique to maintain target coverage under range and setup uncertainties. Dose differences between PB-optimized (PBopt), MC-recalculated (MCrecalc), and MC-optimized (MCopt) plans were recorded for the following region-of-interest metrics: clinical target volume (CTV) V95, CTV homogeneity index (HI), total lung V20, total lung VRX (relative lung volume receiving prescribed dose or higher), and global maximum dose. The impact of PB-based and MC-based planning on robustness to systematic perturbation of range (±3% density) and setup (±3 mm isotropic) was assessed. Pairwise differences in dose parameters were evaluated through non-parametric Friedman and Wilcoxon sign-rank testing. Results In this ten-patient sample, CTV V95 decreased significantly from 99–100% for PBopt to 77–94% for MCrecalc and recovered to 99–100% for MCopt (P<10−5). The median CTV HI (D95/D5) decreased from 0.98 for PBopt to 0.91 for MCrecalc and increased to 0.95 for MCopt (P<10−3). CTV D95 robustness to range and setup errors improved under MCopt (ΔD95 =−1%) compared to MCrecalc (ΔD95 =−6%, P=0.006). No changes in lung dosimetry were observed for large volumes receiving low to intermediate doses (e.g., V20), while differences between PB-based and MC-based planning were noted for small volumes receiving high doses (e.g., VRX). Global maximum patient dose increased from 106% for PBopt to 109% for MCrecalc and 112% for MCopt (P<10−3). Conclusions MC dosimetry revealed a reduction in target dose coverage under PB-based planning that was regained under MC-based planning along with improved plan robustness. MC-based optimization and dose calculation should be integrated into clinical planning workflows of lung cancer patients receiving actively scanned proton therapy. PMID:29876310

SU-F-BRD-15: Quality Correction Factors in Scanned Or Broad Proton Therapy Beams Are Indistinguishable

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sorriaux, J; Lee, J; ICTEAM Institute, Universite catholique de Louvain, Louvain-la-Neuve

2015-06-15

Purpose: The IAEA TRS-398 code of practice details the reference conditions for reference dosimetry of proton beams using ionization chambers and the required beam quality correction factors (kQ). Pencil beam scanning (PBS) requires multiple spots to reproduce the reference conditions. The objective is to demonstrate, using Monte Carlo (MC) calculations, that kQ factors for broad beams can be used for scanned beams under the same reference conditions with no significant additional uncertainty. We consider hereafter the general Alfonso formalism (Alfonso et al, 2008) for non-standard beam. Methods: To approach the reference conditions and the associated dose distributions, PBS must combinemore » many pencil beams with range modulation and shaping techniques different than those used in passive systems (broad beams). This might lead to a different energy spectrum at the measurement point. In order to evaluate the impact of these differences on kQ factors, ion chamber responses are computed with MC (Geant4 9.6) in a dedicated scanned pencil beam (Q-pcsr) producing a 10×10cm2 composite field with a flat dose distribution from 10 to 16 cm depth. Ion chamber responses are also computed by MC in a broad beam with quality Q-ds (double scattering). The dose distribution of Q -pcsr matches the dose distribution of Q-ds. k-(Q-pcsr,Q-ds) is computed for a 2×2×0.2cm{sup 3} idealized air cavity and a realistic plane-parallel ion chamber (IC). Results: Under reference conditions, quality correction factors for a scanned composite field versus a broad beam are the same for air cavity dose response, k-(Q-pcsr,Q-ds) =1.001±0.001 and for a Roos IC, k-(Q-pcsr,Q-ds) =0.999±0.005. Conclusion: Quality correction factors for ion chamber response in scanned and broad proton therapy beams are identical under reference conditions within the calculation uncertainties. The results indicate that quality correction factors published in IAEA TRS-398 can be used for scanned beams in the SOBP of a high-energy proton beam. Jefferson Sorriaux is financed by the Walloon Region under the convention 1217662. Jefferson Sorriaux is sponsored by a public-private partnership IBA - Walloon Region.« less

SU-G-IeP2-11: Measurement of Equilibrium Doses in Computed Tomography: Comparative Study of Ionization and Solid-State Dosimeters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsubara, K; Kobayashi, A; Koshida, K

Purpose: This study aimed to compare equilibrium doses in computed tomography (CT) obtained from ionization and solid-state dosimeters based on the approach presented in the American Association of Physicists in Medicine Report No. 111. The equilibrium doses were also compared with the CT dose index (CTDI) using a 10-cm pencil-type ionization chamber. Methods: A 0.6-cm{sup 3} ionization chamber (10X6-0.6CT) and a solid-state detector (CT Dose Profiler [CTDP]) were calibrated using 80–130 kVp X-ray beams (44.5–55.8 keV of effective energy) from a radiography X-ray machine against a reference ionization dosimeter. Three 16- or 32-cm diameter polymethyl methacrylate (PMMA) phantoms were assembledmore » consecutively on the CT table to obtain equilibrium doses. The 10X6-0.6CT and CTDP were each placed at the center and peripheral holes (12, 3, 6, and 9 o’clock) of the z-center. Central and mean peripheral equilibrium doses were obtained by scanning with longitudinal translation for a length less than the entire phantom length. CTDIs were also obtained with a 10-cm pencil-type ionization chamber (10X6-0.6CT) by scanning a 16- or 32-cm diameter PMMA phantom with one rotation of the X-ray tube. Results: The difference of calibration coefficients between 80 and 130 kVp was 21.1% for the CTDP and 0.7% for the 10X6-0.6CT. The equilibrium doses were higher than the CTDI. Especially at the peripheral positions and 80 kVp, the 10X6-0.6CT showed higher equilibrium doses than CTDP. However, the relation between the equilibrium dose for the 10X6-0.6CT and the CTDP differed depending on the phantom size, scanner type, measurement position, and selected acquisition parameters. Conclusion: The use of a 10-cm pencil-type ionization chamber causes underestimation of the equilibrium dose. The CTDP has a higher energy dependency than the 10X6-0.6CT. The obtained equilibrium doses are different between the 10X6-0.6CT and the CTDP depending on various conditions. This study was supported by JSPS KAKENHI Grant Number 15K09887.« less

Impacts of gantry angle dependent scanning beam properties on proton PBS treatment

NASA Astrophysics Data System (ADS)

Lin, Yuting; Clasie, Benjamin; Lu, Hsiao-Ming; Flanz, Jacob; Shen, Tim; Jee, Kyung-Wook

2017-01-01

While proton beam models in treatment planning systems are generally assumed invariant with respect to the beam deliveries at different gantry angles. Physical properties of scanning pencil beams can change. The gantry angle dependent properties include the delivered charge to the monitor unit chamber, the spot position and the spot shape. The aim of this study is to investigate the extent of the changes and their dosimetric impacts using historical pencil beam scanning (PBS) treatment data. Online beam delivery records at the time of the patient-specific qualify assurance were retrospectively collected for a total of 34 PBS fields from 28 patients treated at our institution. For each field, proton beam properties at two different gantry angles (the planned and zero gantry angles) were extracted by a newly-developed machine log analysis method and used to reconstruct the delivered dose distributions in the cubic water phantom geometry. The reconstructed doses at the two different angles and a planar dose measurement by a 2D ion-chamber array were compared and the dosimetric impacts of the gantry angle dependency were accessed by a 3D γ-index analysis. In addition, the pencil beam spot size was independently characterized as a function of the gantry angle and the beam energy. The dosimetric effects of the perturbed beam shape were also investigated. Comparisons of spot-by-spot beam positions between both gantry angles show a mean deviation of 0.4 and 0.7 mm and a standard deviation of 0.3 and 0.6 mm for x and y directions, respectively. The delivered giga-protons per spot show a percent mean difference and a standard deviation of 0.01% and 0.3%, respectively, from each planned spot weight. These small deviations lead to an excellent agreement in dose comparisons with an average γ passing rate of 99.1%. When each calculation for both planned and zero gantry angles was compared to the measurement, a high correlation in γ values was also observed, also indicating the dosimetric differences are small when a field is delivered at different gantry angles. Utilizing the online beam delivery records, the gantry angle dependencies of the PBS beam delivery were assessed and quantified. The study confirms the variations of the physical properties to be sufficiently small within the clinical tolerances without taking into account the gantry angle variation.

A Truncated Nuclear Norm Regularization Method Based on Weighted Residual Error for Matrix Completion.

PubMed

Qing Liu; Zhihui Lai; Zongwei Zhou; Fangjun Kuang; Zhong Jin

2016-01-01

Low-rank matrix completion aims to recover a matrix from a small subset of its entries and has received much attention in the field of computer vision. Most existing methods formulate the task as a low-rank matrix approximation problem. A truncated nuclear norm has recently been proposed as a better approximation to the rank of matrix than a nuclear norm. The corresponding optimization method, truncated nuclear norm regularization (TNNR), converges better than the nuclear norm minimization-based methods. However, it is not robust to the number of subtracted singular values and requires a large number of iterations to converge. In this paper, a TNNR method based on weighted residual error (TNNR-WRE) for matrix completion and its extension model (ETNNR-WRE) are proposed. TNNR-WRE assigns different weights to the rows of the residual error matrix in an augmented Lagrange function to accelerate the convergence of the TNNR method. The ETNNR-WRE is much more robust to the number of subtracted singular values than the TNNR-WRE, TNNR alternating direction method of multipliers, and TNNR accelerated proximal gradient with Line search methods. Experimental results using both synthetic and real visual data sets show that the proposed TNNR-WRE and ETNNR-WRE methods perform better than TNNR and Iteratively Reweighted Nuclear Norm (IRNN) methods.

Matrix method for acoustic levitation simulation.

PubMed

Andrade, Marco A B; Perez, Nicolas; Buiochi, Flavio; Adamowski, Julio C

2011-08-01

A matrix method is presented for simulating acoustic levitators. A typical acoustic levitator consists of an ultrasonic transducer and a reflector. The matrix method is used to determine the potential for acoustic radiation force that acts on a small sphere in the standing wave field produced by the levitator. The method is based on the Rayleigh integral and it takes into account the multiple reflections that occur between the transducer and the reflector. The potential for acoustic radiation force obtained by the matrix method is validated by comparing the matrix method results with those obtained by the finite element method when using an axisymmetric model of a single-axis acoustic levitator. After validation, the method is applied in the simulation of a noncontact manipulation system consisting of two 37.9-kHz Langevin-type transducers and a plane reflector. The manipulation system allows control of the horizontal position of a small levitated sphere from -6 mm to 6 mm, which is done by changing the phase difference between the two transducers. The horizontal position of the sphere predicted by the matrix method agrees with the horizontal positions measured experimentally with a charge-coupled device camera. The main advantage of the matrix method is that it allows simulation of non-symmetric acoustic levitators without requiring much computational effort.

Optical matrix-matrix multiplication method demonstrated by the use of a multifocus hololens

NASA Technical Reports Server (NTRS)

Liu, H. K.; Liang, Y.-Z.

1984-01-01

A method of optical matrix-matrix multiplication is presented. The feasibility of the method is also experimentally demonstrated by the use of a dichromated-gelatin multifocus holographic lens (hololens). With the specific values of matrices chosen, the average percentage error between the theoretical and experimental data of the elements of the output matrix of the multiplication of some specific pairs of 3 x 3 matrices is 0.4 percent, which corresponds to an 8-bit accuracy.

Interference Lattice-based Loop Nest Tilings for Stencil Computations

NASA Technical Reports Server (NTRS)

VanderWijngaart, Rob F.; Frumkin, Michael

2000-01-01

A common method for improving performance of stencil operations on structured multi-dimensional discretization grids is loop tiling. Tile shapes and sizes are usually determined heuristically, based on the size of the primary data cache. We provide a lower bound on the numbers of cache misses that must be incurred by any tiling, and a close achievable bound using a particular tiling based on the grid interference lattice. The latter tiling is used to derive highly efficient loop orderings. The total number of cache misses of a code is the sum of (necessary) cold misses and misses caused by elements being dropped from the cache between successive loads (replacement misses). Maximizing temporal locality is equivalent to minimizing replacement misses. Temporal locality of loop nests implementing stencil operations is optimized by tilings that avoid data conflicts. We divide the loop nest iteration space into conflict-free tiles, derived from the cache miss equation. The tiling involves the definition of the grid interference lattice an equivalence class of grid points whose images in main memory map to the same location in the cache-and the construction of a special basis for the lattice. Conflicts only occur on the boundaries of the tiles, unless the tiles are too thin. We show that the surface area of the tiles is bounded for grids of any dimensionality, and for caches of any associativity, provided the eccentricity of the fundamental parallelepiped (the tile spanned by the basis) of the lattice is bounded. Eccentricity is determined by two factors, aspect ratio and skewness. The aspect ratio of the parallelepiped can be bounded by appropriate array padding. The skewness can be bounded by the choice of a proper basis. Combining these two strategies ensures that pathologically thin tiles are avoided. They do not, however, minimize replacement misses per se. The reason is that tile visitation order influences the number of data conflicts on the tile boundaries. If two adjacent tiles are visited successively, there will be no replacement misses on the shared boundary. The iteration space may be covered with pencils larger than the size of the cache while avoiding data conflicts if the pencils are traversed by a scanning-face method. Replacement misses are incurred only on the boundaries of the pencils, and the number of misses is minimized by maximizing the volume of the scanning face, not the volume of the tile. We present an algorithm for constructing the most efficient scanning face for a given grid and stencil operator. In two dimensions it is based on a continued fraction algorithm. In three dimensions it follows Voronoi's successive minima algorithm. We show experimental results of using the scanning face, and compare with canonical loop orderings.

Assessment techniques for a learning-centered curriculum: evaluation design for adventures in supercomputing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Helland, B.; Summers, B.G.

1996-09-01

As the classroom paradigm shifts from being teacher-centered to being learner-centered, student assessments are evolving from typical paper and pencil testing to other methods of evaluation. Students should be probed for understanding, reasoning, and critical thinking abilities rather than their ability to return memorized facts. The assessment of the Department of Energy`s pilot program, Adventures in Supercomputing (AiS), offers one example of assessment techniques developed for learner-centered curricula. This assessment has employed a variety of methods to collect student data. Methods of assessment used were traditional testing, performance testing, interviews, short questionnaires via email, and student presentations of projects. Themore » data obtained from these sources have been analyzed by a professional assessment team at the Center for Children and Technology. The results have been used to improve the AiS curriculum and establish the quality of the overall AiS program. This paper will discuss the various methods of assessment used and the results.« less

The Bioactivity of Cartilage Extracellular Matrix in Articular Cartilage Regeneration

PubMed Central

Sutherland, Amanda J.; Converse, Gabriel L.; Hopkins, Richard A.; Detamore, Michael S.

2014-01-01

Cartilage matrix is a particularly promising acellular material for cartilage regeneration given the evidence supporting its chondroinductive character. The ‘raw materials’ of cartilage matrix can serve as building blocks and signals for enhanced tissue regeneration. These matrices can be created by chemical or physical methods: physical methods disrupt cellular membranes and nuclei but may not fully remove all cell components and DNA, whereas chemical methods when combined with physical methods are particularly effective in fully decellularizing such materials. Critical endpoints include no detectable residual DNA or immunogenic antigens. It is important to first delineate between the sources of the cartilage matrix, i.e., derived from matrix produced by cells in vitro or from native tissue, and then to further characterize the cartilage matrix based on the processing method, i.e., decellularization or devitalization. With these distinctions, four types of cartilage matrices exist: decellularized native cartilage (DCC), devitalized native cartilage (DVC), decellularized cell derived matrix (DCCM), and devitalized cell derived matrix (DVCM). Delivery of cartilage matrix may be a straightforward approach without the need for additional cells or growth factors. Without additional biological additives, cartilage matrix may be attractive from a regulatory and commercialization standpoint. Source and delivery method are important considerations for clinical translation. Only one currently marketed cartilage matrix medical device is decellularized, although trends in filed patents suggest additional decellularized products may be available in the future. To choose the most relevant source and processing for cartilage matrix, qualifying testing needs to include targeting the desired application, optimizing delivery of the material, identify relevant FDA regulations, assess availability of raw materials, and immunogenic properties of the product. PMID:25044502

Novel image analysis methods for quantification of in situ 3-D tendon cell and matrix strain.

PubMed

Fung, Ashley K; Paredes, J J; Andarawis-Puri, Nelly

2018-01-23

Macroscopic tendon loads modulate the cellular microenvironment leading to biological outcomes such as degeneration or repair. Previous studies have shown that damage accumulation and the phases of tendon healing are marked by significant changes in the extracellular matrix, but it remains unknown how mechanical forces of the extracellular matrix are translated to mechanotransduction pathways that ultimately drive the biological response. Our overarching hypothesis is that the unique relationship between extracellular matrix strain and cell deformation will dictate biological outcomes, prompting the need for quantitative methods to characterize the local strain environment. While 2-D methods have successfully calculated matrix strain and cell deformation, 3-D methods are necessary to capture the increased complexity that can arise due to high levels of anisotropy and out-of-plane motion, particularly in the disorganized, highly cellular, injured state. In this study, we validated the use of digital volume correlation methods to quantify 3-D matrix strain using images of naïve tendon cells, the collagen fiber matrix, and injured tendon cells. Additionally, naïve tendon cell images were used to develop novel methods for 3-D cell deformation and 3-D cell-matrix strain, which is defined as a quantitative measure of the relationship between matrix strain and cell deformation. The results support that these methods can be used to detect strains with high accuracy and can be further extended to an in vivo setting for observing temporal changes in cell and matrix mechanics during degeneration and healing. Copyright © 2017. Published by Elsevier Ltd.

Maximum entropy formalism for the analytic continuation of matrix-valued Green's functions

NASA Astrophysics Data System (ADS)

Kraberger, Gernot J.; Triebl, Robert; Zingl, Manuel; Aichhorn, Markus

2017-10-01

We present a generalization of the maximum entropy method to the analytic continuation of matrix-valued Green's functions. To treat off-diagonal elements correctly based on Bayesian probability theory, the entropy term has to be extended for spectral functions that are possibly negative in some frequency ranges. In that way, all matrix elements of the Green's function matrix can be analytically continued; we introduce a computationally cheap element-wise method for this purpose. However, this method cannot ensure important constraints on the mathematical properties of the resulting spectral functions, namely positive semidefiniteness and Hermiticity. To improve on this, we present a full matrix formalism, where all matrix elements are treated simultaneously. We show the capabilities of these methods using insulating and metallic dynamical mean-field theory (DMFT) Green's functions as test cases. Finally, we apply the methods to realistic material calculations for LaTiO3, where off-diagonal matrix elements in the Green's function appear due to the distorted crystal structure.

Theory and implementation of H-matrix based iterative and direct solvers for Helmholtz and elastodynamic oscillatory kernels

NASA Astrophysics Data System (ADS)

Chaillat, Stéphanie; Desiderio, Luca; Ciarlet, Patrick

2017-12-01

In this work, we study the accuracy and efficiency of hierarchical matrix (H-matrix) based fast methods for solving dense linear systems arising from the discretization of the 3D elastodynamic Green's tensors. It is well known in the literature that standard H-matrix based methods, although very efficient tools for asymptotically smooth kernels, are not optimal for oscillatory kernels. H2-matrix and directional approaches have been proposed to overcome this problem. However the implementation of such methods is much more involved than the standard H-matrix representation. The central questions we address are twofold. (i) What is the frequency-range in which the H-matrix format is an efficient representation for 3D elastodynamic problems? (ii) What can be expected of such an approach to model problems in mechanical engineering? We show that even though the method is not optimal (in the sense that more involved representations can lead to faster algorithms) an efficient solver can be easily developed. The capabilities of the method are illustrated on numerical examples using the Boundary Element Method.

Analytical quality assurance in veterinary drug residue analysis methods: matrix effects determination and monitoring for sulfonamides analysis.

PubMed

Hoff, Rodrigo Barcellos; Rübensam, Gabriel; Jank, Louise; Barreto, Fabiano; Peralba, Maria do Carmo Ruaro; Pizzolato, Tânia Mara; Silvia Díaz-Cruz, M; Barceló, Damià

2015-01-01

In residue analysis of veterinary drugs in foodstuff, matrix effects are one of the most critical points. This work present a discuss considering approaches used to estimate, minimize and monitoring matrix effects in bioanalytical methods. Qualitative and quantitative methods for estimation of matrix effects such as post-column infusion, slopes ratios analysis, calibration curves (mathematical and statistical analysis) and control chart monitoring are discussed using real data. Matrix effects varying in a wide range depending of the analyte and the sample preparation method: pressurized liquid extraction for liver samples show matrix effects from 15.5 to 59.2% while a ultrasound-assisted extraction provide values from 21.7 to 64.3%. The matrix influence was also evaluated: for sulfamethazine analysis, losses of signal were varying from -37 to -96% for fish and eggs, respectively. Advantages and drawbacks are also discussed considering a workflow for matrix effects assessment proposed and applied to real data from sulfonamides residues analysis. Copyright © 2014 Elsevier B.V. All rights reserved.

A Lesson in Values.

ERIC Educational Resources Information Center

Deahl, Patricia Herz

2002-01-01

Describes a seventh-grade art project used to help students explore different types of art mediums. Focuses on each of the four parts of the project: (1) pencil; (2) pen and ink; (3) paint; and (4) collage. (CMK)

7 CFR 4285.25 - Authorized use of cooperative agreement funds.

Code of Federal Regulations, 2010 CFR

2010-01-01

... cooperator determines it to be more economical than renting. However, as a general rule, these types of... office supplies (such as paper, pens, pencils, and trade magazines) and postage needed for project...

Genetics Home Reference: 19p13.13 deletion syndrome

MedlinePlus

... and walking) and fine motor skills (such as holding a pencil). Other signs and symptoms that can ... during the formation of reproductive cells (eggs and sperm) or in early fetal development. Most affected people ...

7 CFR 1944.405 - Authorized use of grant funds.

Code of Federal Regulations, 2013 CFR

2013-01-01

... multiple funded organizations. (c) Purchase of office supplies such as paper, pens, pencils, and trade... Director). (j) Payments of the cost of an accountant to set up an accounting system and perform audits that...

7 CFR 1944.405 - Authorized use of grant funds.

Code of Federal Regulations, 2012 CFR

2012-01-01

... multiple funded organizations. (c) Purchase of office supplies such as paper, pens, pencils, and trade... Director). (j) Payments of the cost of an accountant to set up an accounting system and perform audits that...

7 CFR 1944.405 - Authorized use of grant funds.

Code of Federal Regulations, 2014 CFR

2014-01-01

... multiple funded organizations. (c) Purchase of office supplies such as paper, pens, pencils, and trade... Director). (j) Payments of the cost of an accountant to set up an accounting system and perform audits that...

Real-time proton beam range monitoring by means of prompt-gamma detection with a collimated camera

NASA Astrophysics Data System (ADS)

Roellinghoff, F.; Benilov, A.; Dauvergne, D.; Dedes, G.; Freud, N.; Janssens, G.; Krimmer, J.; Létang, J. M.; Pinto, M.; Prieels, D.; Ray, C.; Smeets, J.; Stichelbaut, F.; Testa, E.

2014-03-01

Prompt-gamma profile was measured at WPE-Essen using 160 MeV protons impinging a movable PMMA target. A single collimated detector was used with time-of-flight (TOF) to reduce the background due to neutrons. The target entrance rise and the Bragg peak falloff retrieval precision was determined as a function of incident proton number by a fitting procedure using independent data sets. Assuming improved sensitivity of this camera design by using a greater number of detectors, retrieval precisions of 1 to 2 mm (rms) are expected for a clinical pencil beam. TOF improves the contrast-to-noise ratio and the performance of the method significantly.

Evaluation of Computer Based Testing in lieu of Regular Examinations in Computer Literacy

NASA Astrophysics Data System (ADS)

Murayama, Koichi

Because computer based testing (CBT) has many advantages compared with the conventional paper and pencil testing (PPT) examination method, CBT has begun to be used in various situations in Japan, such as in qualifying examinations and in the TOEFL. This paper describes the usefulness and the problems of CBT applied to a regular college examination. The regular computer literacy examinations for first year students were held using CBT, and the results were analyzed. Responses to a questionnaire indicated many students accepted CBT with no unpleasantness and considered CBT a positive factor, improving their motivation to study. CBT also decreased the work of faculty in terms of marking tests and reducing data.

The Dental Health of Army Family Members: 1987-1988. Volume 1. Introduction and Methods/Characteristics of Study Sample/Dental Treatment Needs

DTIC Science & Technology

1990-05-07

No (31). HSC Form 539 (OT) (HCSCIA) 1 MAY 87 Page 1 of 4 Pages 43 Use Pencil Only To Record On This Form DMFS PERIO SURFACES N C MEASUREMENTS PERIOTX...USE SURFACES, NEEDS, AND CLASS CODES) NEEDS Rads Used Codes PERIO C 1 = PAX D L 2 = BWX D S s A 3 = PANX M C U ARasF A R S Rads Tooth # SURFACES s L...G S DMFS Needs Codes - To -thd M 0 1 D2. F I L (587- 598) ADD: E = Endo - (599- 610) (611-622) (623-634) (635- 646) (647- 658) IMPORTANT - IF

A fast ultrasonic simulation tool based on massively parallel implementations

NASA Astrophysics Data System (ADS)

Lambert, Jason; Rougeron, Gilles; Lacassagne, Lionel; Chatillon, Sylvain

2014-02-01

This paper presents a CIVA optimized ultrasonic inspection simulation tool, which takes benefit of the power of massively parallel architectures: graphical processing units (GPU) and multi-core general purpose processors (GPP). This tool is based on the classical approach used in CIVA: the interaction model is based on Kirchoff, and the ultrasonic field around the defect is computed by the pencil method. The model has been adapted and parallelized for both architectures. At this stage, the configurations addressed by the tool are : multi and mono-element probes, planar specimens made of simple isotropic materials, planar rectangular defects or side drilled holes of small diameter. Validations on the model accuracy and performances measurements are presented.

Prompt gamma timing range verification for scattered proton beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kormoll, T.; Golnik, C.; Hueso Gonzalez, F.

2015-07-01

Range verification is a very important point in order to fully exploit the physical advantages of protons compared to photons in cancer irradiation. Recently, a simple method has been proposed which makes use of the time of fight of protons in tissue and the promptly emitted secondary photons along the proton path (Prompt Gamma Timing, PGT). This has been considered so far for monoenergetic pencil beams only. In this work, it has been studied whether this technique can also be applied in passively formed irradiation fields with a so called spread out Bragg peak. Time correlated profiles could be recorded,more » which show a trend that is consistent with theoretical predictions. (authors)« less

Fast Minimum Variance Beamforming Based on Legendre Polynomials.

PubMed

Bae, MooHo; Park, Sung Bae; Kwon, Sung Jae

2016-09-01

Currently, minimum variance beamforming (MV) is actively investigated as a method that can improve the performance of an ultrasound beamformer, in terms of the lateral and contrast resolution. However, this method has the disadvantage of excessive computational complexity since the inverse spatial covariance matrix must be calculated. Some noteworthy methods among various attempts to solve this problem include beam space adaptive beamforming methods and the fast MV method based on principal component analysis, which are similar in that the original signal in the element space is transformed to another domain using an orthonormal basis matrix and the dimension of the covariance matrix is reduced by approximating the matrix only with important components of the matrix, hence making the inversion of the matrix very simple. Recently, we proposed a new method with further reduced computational demand that uses Legendre polynomials as the basis matrix for such a transformation. In this paper, we verify the efficacy of the proposed method through Field II simulations as well as in vitro and in vivo experiments. The results show that the approximation error of this method is less than or similar to those of the above-mentioned methods and that the lateral response of point targets and the contrast-to-speckle noise in anechoic cysts are also better than or similar to those methods when the dimensionality of the covariance matrices is reduced to the same dimension.

Calculation of light delay for coupled microrings by FDTD technique and Padé approximation.

PubMed

Huang, Yong-Zhen; Yang, Yue-De

2009-11-01

The Padé approximation with Baker's algorithm is compared with the least-squares Prony method and the generalized pencil-of-functions (GPOF) method for calculating mode frequencies and mode Q factors for coupled optical microdisks by FDTD technique. Comparisons of intensity spectra and the corresponding mode frequencies and Q factors show that the Padé approximation can yield more stable results than the Prony and the GPOF methods, especially the intensity spectrum. The results of the Prony method and the GPOF method are greatly influenced by the selected number of resonant modes, which need to be optimized during the data processing, in addition to the length of the time response signal. Furthermore, the Padé approximation is applied to calculate light delay for embedded microring resonators from complex transmission spectra obtained by the Padé approximation from a FDTD output. The Prony and the GPOF methods cannot be applied to calculate the transmission spectra, because the transmission signal obtained by the FDTD simulation cannot be expressed as a sum of damped complex exponentials.

Convergence analysis of modulus-based matrix splitting iterative methods for implicit complementarity problems.

PubMed

Wang, An; Cao, Yang; Shi, Quan

2018-01-01

In this paper, we demonstrate a complete version of the convergence theory of the modulus-based matrix splitting iteration methods for solving a class of implicit complementarity problems proposed by Hong and Li (Numer. Linear Algebra Appl. 23:629-641, 2016). New convergence conditions are presented when the system matrix is a positive-definite matrix and an [Formula: see text]-matrix, respectively.

Algorithms for Solvents and Spectral Factors of Matrix Polynomials

DTIC Science & Technology

1981-01-01

spectral factors of matrix polynomials LEANG S. SHIEHt, YIH T. TSAYt and NORMAN P. COLEMANt A generalized Newton method , based on the contracted gradient...of a matrix poly- nomial, is derived for solving the right (left) solvents and spectral factors of matrix polynomials. Two methods of selecting initial...estimates for rapid convergence of the newly developed numerical method are proposed. Also, new algorithms for solving complete sets of the right

A sample preparation method for recovering suppressed analyte ions in MALDI TOF MS.

PubMed

Lou, Xianwen; de Waal, Bas F M; Milroy, Lech-Gustav; van Dongen, Joost L J

2015-05-01

In matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS), analyte signals can be substantially suppressed by other compounds in the sample. In this technical note, we describe a modified thin-layer sample preparation method that significantly reduces the analyte suppression effect (ASE). In our method, analytes are deposited on top of the surface of matrix preloaded on the MALDI plate. To prevent embedding of analyte into the matrix crystals, the sample solution were prepared without matrix and efforts were taken not to re-dissolve the preloaded matrix. The results with model mixtures of peptides, synthetic polymers and lipids show that detection of analyte ions, which were completely suppressed using the conventional dried-droplet method, could be effectively recovered by using our method. Our findings suggest that the incorporation of analytes in the matrix crystals has an important contributory effect on ASE. By reducing ASE, our method should be useful for the direct MALDI MS analysis of multicomponent mixtures. Copyright © 2015 John Wiley & Sons, Ltd.

Quantitative evaluation of the matrix effect in bioanalytical methods based on LC-MS: A comparison of two approaches.

PubMed

Rudzki, Piotr J; Gniazdowska, Elżbieta; Buś-Kwaśnik, Katarzyna

2018-06-05

Liquid chromatography coupled to mass spectrometry (LC-MS) is a powerful tool for studying pharmacokinetics and toxicokinetics. Reliable bioanalysis requires the characterization of the matrix effect, i.e. influence of the endogenous or exogenous compounds on the analyte signal intensity. We have compared two methods for the quantitation of matrix effect. The CVs(%) of internal standard normalized matrix factors recommended by the European Medicines Agency were evaluated against internal standard normalized relative matrix effects derived from Matuszewski et al. (2003). Both methods use post-extraction spiked samples, but matrix factors require also neat solutions. We have tested both approaches using analytes of diverse chemical structures. The study did not reveal relevant differences in the results obtained with both calculation methods. After normalization with the internal standard, the CV(%) of the matrix factor was on average 0.5% higher than the corresponding relative matrix effect. The method adopted by the European Medicines Agency seems to be slightly more conservative in the analyzed datasets. Nine analytes of different structures enabled a general overview of the problem, still, further studies are encouraged to confirm our observations. Copyright © 2018 Elsevier B.V. All rights reserved.

Magnet-wire wrapping tool for integrated circuits

NASA Technical Reports Server (NTRS)

Takahashi, T. H.

1972-01-01

Wire-dispensing tool which resembles mechanical pencil is used to wrap magnet wire around integrated circuit terminals uniformly and securely without damaging insulative coating on wire. Tool is hand-held and easily manipulated to execute wire wrapping movements.

The Ocean Book: Food Chains...Come and Eat!

ERIC Educational Resources Information Center

Science Activities, 1989

1989-01-01

Six paper and pencil activities on marine ecology are presented with answers. Included are a food pyramid, a maze, a find-a-word puzzle, a sea food chain, a crossword puzzle, and a predator-prey puzzle. (CW)

Administering Spatial and Cognitive Instruments In-class and On-line: Are These Equivalent?

NASA Astrophysics Data System (ADS)

Williamson, Kenneth C.; Williamson, Vickie M.; Hinze, Scott R.

2017-02-01

Standardized, well-established paper-and-pencil tests, which measure spatial abilities or which measure reasoning abilities, have long been found to be predictive of success in the STEM (science, technology, engineering, and mathematics) fields. Instructors can use these tests for prediction of success and to inform instruction. A comparative administration of spatial visualization and cognitive reasoning tests, between in-class (proctored paper and pencil) and on-line (unproctored Internet) ( N = 457), was used to investigate and to determine whether the differing instrument formats yielded equal measures of spatial ability and reasoning ability in large first-semester general chemistry sections. Although some gender differences were found, findings suggest that some differences across administration formats, but that on-line administration had similar properties of predicting chemistry performance as the in-class version. Therefore, on-line administration is a viable option for instructors to consider especially when dealing with large classes.

Teaching treatment planning for protons with educational open-source software: experience with FoCa and matRad.

PubMed

Sanchez-Parcerisa, Daniel; Udías, Jose

2018-05-12

Open-source, MATLAB-based treatment planning systems FoCa and matRAD were used in a pilot project for training prospective medical physicists and postgraduate physics students in treatment planning and beam modeling techniques for proton therapy. In the four exercises designed, students learnt how proton pencil beams are modeled and how dose is calculated in three-dimensional voxelized geometries, how pencil beam scanning plans (PBS) are constructed, the rationale behind the choice of spot spacing in patient plans, and the dosimetric differences between photon IMRT and proton PBS plans. Sixty students of two courses participated in the pilot project, with over 90% of satisfactory rating from student surveys. The pilot experience will certainly be continued. © 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

De novo Assembly and Analysis of the Chilean Pencil Catfish Trichomycterus areolatus Transcriptome

PubMed Central

Schulze, Thomas T.; Ali, Jonathan M.; Bartlett, Maggie L.; McFarland, Madalyn M.; Clement, Emalie J.; Won, Harim I.; Sanford, Austin G.; Monzingo, Elyssa B.; Martens, Matthew C.; Hemsley, Ryan M.; Kumar, Sidharta; Gouin, Nicolas; Kolok, Alan S.; Davis, Paul H.

2016-01-01

Trichomycterus areolatus is an endemic species of pencil catfish that inhabits the riffles and rapids of many freshwater ecosystems of Chile. Despite its unique adaptation to Chile's high gradient watersheds and therefore potential application in the investigation of ecosystem integrity and environmental contamination, relatively little is known regarding the molecular biology of this environmental sentinel. Here, we detail the assembly of the Trichomycterus areolatus transcriptome, a molecular resource for the study of this organism and its molecular response to the environment. RNA-Seq reads were obtained by next-generation sequencing with an Illumina® platform and processed using PRINSEQ. The transcriptome assembly was performed using TRINITY assembler. Transcriptome validation was performed by functional characterization with KOG, KEGG, and GO analyses. Additionally, differential expression analysis highlights sex-specific expression patterns, and a list of endocrine and oxidative stress related transcripts are included. PMID:27672404

Instant power generation from an air-breathing paper and pencil based bacterial bio-fuel cell.

PubMed

Veerubhotla, Ramya; Bandopadhyay, Aditya; Das, Debabrata; Chakraborty, Suman

2015-06-21

We present a low-cost, disposable microbial fuel cell fabricated on a paper based platform, having a start-up time of 10 s. The platform deploys ordinary pencil strokes for graphite electrode deposition. The device uses a membrane-less design in a one-time injection (OTI) mode or a continuous capillary driven flow mode (CPF), where oxygen from the atmosphere is used up at the cathode for water formation, leading to the generation of bioelectricity. The performance of the fuel cell is evaluated using two bacterial strains, namely, Pseudomonas aeruginosa IIT BT SS1 and Shewanella putrefaciens. This flexible device is shown to retain bacteria for a period of at least one hour, resulting in the generation of almost 0.4 V using P. aeruginosa and a maximum current of 18 μA using S. putrefaciens without the use of any additional catalysts.

KSC-07pd1407

NASA Image and Video Library

2007-06-07

KENNEDY SPACE CENTER, FLA. -- The "pencil sharpener" tool designed to trim the hand-sprayed foam repairs on the STS-117 external tank is on display for the media at the NASA News Center. This portable tool was designed in just 10 days specifically for this task by Lockheed Martin engineer Glenn Lapeyronnie at the Michoud external tank manufacturing facility in New Orleans. The pencil sharpener tool fits over the external tank nose cone spike at the top of the tank and extends down to where the hand-sprayed foam was used to repair the hail-damaged areas. The hail damage was incurred Feb. 28 while Space Shuttle Atlantis was on the launch pad for a March 15 launch. The shuttle returned to the Vehicle Assembly Building so that repairs could be made. Mission STS-117 is scheduled to launch at 7:38 p.m. EDT on June 8. Photo credit: NASA/Jack Pfaller

KSC-07pd1405

NASA Image and Video Library

2007-06-07

KENNEDY SPACE CENTER, FLA. -- The "pencil sharpener" tool designed to trim the hand-sprayed foam repairs on the STS-117 external tank is on display for the media at the NASA News Center. This portable tool was designed in just 10 days specifically for this task by Lockheed Martin engineer Glenn Lapeyronnie at the Michoud external tank manufacturing facility in New Orleans. The pencil sharpener tool fits over the external tank nose cone spike at the top of the tank and extends down to where the hand-sprayed foam was used to repair the hail-damaged areas. The hail damage was incurred Feb. 28 while Space Shuttle Atlantis was on the launch pad for a March 15 launch. The shuttle returned to the Vehicle Assembly Building so that repairs could be made. Mission STS-117 is scheduled to launch at 7:38 p.m. EDT on June 8. Photo credit: NASA/Jack Pfaller

KSC-07pd1406

NASA Image and Video Library

2007-06-07

KENNEDY SPACE CENTER, FLA. -- The "pencil sharpener" tool designed to trim the hand-sprayed foam repairs on the STS-117 external tank is on display for the media at the NASA News Center. This portable tool was designed in just 10 days specifically for this task by Lockheed Martin engineer Glenn Lapeyronnie at the Michoud external tank manufacturing facility in New Orleans. The pencil sharpener tool fits over the external tank nose cone spike at the top of the tank and extends down to where the hand-sprayed foam was used to repair the hail-damaged areas. The hail damage was incurred Feb. 28 while Space Shuttle Atlantis was on the launch pad for a March 15 launch. The shuttle returned to the Vehicle Assembly Building so that repairs could be made. Mission STS-117 is scheduled to launch at 7:38 p.m. EDT on June 8. Photo credit: NASA/Jack Pfaller

KSC-07pd1408

NASA Image and Video Library

2007-06-07

KENNEDY SPACE CENTER, FLA. -- The "pencil sharpener" tool designed to trim the hand-sprayed foam repairs on the STS-117 external tank is on display for the media at the NASA News Center. This portable tool was designed in just 10 days specifically for this task by Lockheed Martin engineer Glenn Lapeyronnie at the Michoud external tank manufacturing facility in New Orleans. The pencil sharpener tool fits over the external tank nose cone spike at the top of the tank and extends down to where the hand-sprayed foam was used to repair the hail-damaged areas. The hail damage was incurred Feb. 28 while Space Shuttle Atlantis was on the launch pad for a March 15 launch. The shuttle returned to the Vehicle Assembly Building so that repairs could be made. Mission STS-117 is scheduled to launch at 7:38 p.m. EDT on June 8. Photo credit: NASA/Jack Pfaller

Direct Iterative Nonlinear Inversion by Multi-frequency T-matrix Completion

NASA Astrophysics Data System (ADS)

Jakobsen, M.; Wu, R. S.

2016-12-01

Researchers in the mathematical physics community have recently proposed a conceptually new method for solving nonlinear inverse scattering problems (like FWI) which is inspired by the theory of nonlocality of physical interactions. The conceptually new method, which may be referred to as the T-matrix completion method, is very interesting since it is not based on linearization at any stage. Also, there are no gradient vectors or (inverse) Hessian matrices to calculate. However, the convergence radius of this promising T-matrix completion method is seriously restricted by it's use of single-frequency scattering data only. In this study, we have developed a modified version of the T-matrix completion method which we believe is more suitable for applications to nonlinear inverse scattering problems in (exploration) seismology, because it makes use of multi-frequency data. Essentially, we have simplified the single-frequency T-matrix completion method of Levinson and Markel and combined it with the standard sequential frequency inversion (multi-scale regularization) method. For each frequency, we first estimate the experimental T-matrix by using the Moore-Penrose pseudo inverse concept. Then this experimental T-matrix is used to initiate an iterative procedure for successive estimation of the scattering potential and the T-matrix using the Lippmann-Schwinger for the nonlinear relation between these two quantities. The main physical requirements in the basic iterative cycle is that the T-matrix should be data-compatible and the scattering potential operator should be dominantly local; although a non-local scattering potential operator is allowed in the intermediate iterations. In our simplified T-matrix completion strategy, we ensure that the T-matrix updates are always data compatible simply by adding a suitable correction term in the real space coordinate representation. The use of singular-value decomposition representations are not required in our formulation since we have developed an efficient domain decomposition method. The results of several numerical experiments for the SEG/EAGE salt model illustrate the importance of using multi-frequency data when performing frequency domain full waveform inversion in strongly scattering media via the new concept of T-matrix completion.