Numerical Data (numerical + data)

Distribution by Scientific Domains


Selected Abstracts


Bench,shelf system dynamic characteristics and their effects on equipment and contents

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 13 2006
Tara C. Hutchinson
Abstract Economic losses during past earthquakes are strongly associated with damage and failure to nonstructural equipment and contents. Among the vast types of nonstructural elements, one important category, is scientific equipment in biological or chemical laboratories. These equipment are often mounted on heavy ceramic bench-tops of bench,shelf systems, which in turn may amplify the dynamic motions imposed. To investigate the seismic response of these types of systems, a series of shake table and field experiments were conducted considering different representative bench and shelf-mounted equipment and contents. Results from shake table experiments indicate that these equipment are generally sliding-dominated. In addition, the bench,shelf system is observed to be very stiff and when lightly loaded, has a fundamental frequency between 10 and 16 Hz. An approximate 50% reduction in the first and second fundamental frequencies is observed considering practical loading conditions. Insight into a broader range of system response is provided by conducting eigenvalue and time history analyses. Non-linear regression through the numerical data indicate acceleration amplification ratios , range from 2.6 to 1.4 and from 4.3 to 1.6, for fixed,fixed and pinned,pinned conditions, respectively. Both the experimental and numerical results support the importance of determining the potential dynamic amplification of motion in the context of accurately determining the maximum sliding displacement of support equipment and contents. Copyright © 2006 John Wiley & Sons, Ltd. [source]


A confocal micro-endoscopic investigation of the relationship between the microhardness of carious dentine and its autofluorescence

EUROPEAN JOURNAL OF ORAL SCIENCES, Issue 1 2010
Avijit Banerjee
Banerjee A, Cook R, Kellow S, Shah K, Festy F, Sherriff M, Watson T. A confocal micro-endoscopic investigation of the relationship between the microhardness of carious dentine and its autofluorescence. Eur J Oral Sci 2010; 118: 75,79. © 2010 The Authors. Journal compilation© 2010 Eur J Oral Sci This study aimed to investigate the null hypothesis that there is no relationship between the microhardness of carious dentine and its native autofluorescence (AF). Six extracted, carious molars were sectioned through natural lesions in the mesio-distal longitudinal plane. The Knoop microhardness (Knoop hardness number, KHN) of the cut surfaces of each sample was recorded at regular intervals through sound and carious dentine. Confocal fibre-optic micro-endoscopic (CFOME) examination of the carious dentine and the sound dentine was carried out at the same intervals using the Cellvizio system (600 ,m wide, flat-end probe) with an excitation wavelength of 488 nm. The blindly collected numerical data were analysed using the original microhardness KHN. The data analysis indicated that the autofluorescence signals increased significantly when the microhardness of dentine dropped below 25 KHN. Therefore, the null hypothesis was disproved, and it was concluded from this investigation that the autofluorescent signal intensity recorded using CFOME could produce an objective and reproducible correlation to the microhardness of carious dentine. Confocal fibre-optic micro-endoscopic examination could have clinical potential as a technology to help delineate the carious dentine that might be excavated in a clinical procedure in vivo. [source]


RESISTANCE OF SPIDERS TO CRETACEOUS-TERTIARY EXTINCTION EVENTS

EVOLUTION, Issue 11 2003
David Penney
Abstract Throughout Earth history a small number of global catastrophic events leading to biotic crises have caused mass extinctions. Here, using a technique that combines taxonomic and numerical data, we consider the effects of the Cenomanian,Turonian and Cretaceous,Tertiary mass extinctions on the terrestrial spider fauna in the light of new fossil data. We provide the first evidence that spiders suffered no decline at the family level during these mass extinction events. On the contrary, we show that they increased in relative numbers through the Cretaceous and beyond the Cretaceous,Tertiary extinction event. [source]


A Model-Based Method for an Online Diagnostic Knowledge-Based System

EXPERT SYSTEMS, Issue 3 2001
Chrissanthi Angeli
Fault diagnosis is very important for modern production technology and has received increasing theoretical and practical attention during the last few years. This paper presents a model-based diagnostic method for industrial systems. An online, real-time, deep knowledge based fault detection system has been developed by combining different development environments and tools. The system diagnoses, predicts and compensates faults by coupling symbolic and numerical data in a new environment suitable for the interaction of different sources of knowledge and has been successfully implemented and tested on a real hydraulic system. [source]


Infilling of sparse 3D data for 3D focusing operator estimation

GEOPHYSICAL PROSPECTING, Issue 6 2004
M.J. Van De Rijzen
ABSTRACT Seismic migration can be formulated in terms of two consecutive downward extrapolation steps: refocusing the receivers and refocusing the sources. Applying only the first focusing step with an estimate of the focusing operators results in a common focal point (CFP) gather for each depth point at a reflecting boundary. The CFP gathers, in combination with the estimates of the focusing operators, can be used in an iterative procedure to obtain the correct operators. However, current 3D seismic data acquisition geometries do not contain the dense spatial sampling required for calculation of full 3D CFP gathers. We report on the construction of full 3D CFP gathers using a non-full 3D acquisition geometry. The proposed method uses a reflector-orientated data infill procedure based on the azimuthal redundancy of the reflection data. The results on 3D numerical data in this paper show that full 3D CFP gathers, which are kinematically and dynamically correct for the target event, can be obtained. These gathers can be used for iterative updating of the 3D focusing operators. [source]


Determination of rock mass strength properties by homogenization

INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 13 2001
A. Pouya
Abstract A method for determining fractured rock mass properties is presented here on the basis of homogenization approach. The rock mass is considered to be a heterogeneous medium composed of intact rock and of fractures. Its constitutive model is studied numerically using finite element method and assimilating the fractures to joint elements (Coste, Comportement Thermo-Hydro-Mécanique des massifs rocheux fracturés. Thèse de Doctorat, Ecole Nationale des Ponts et Chaussées, Paris, 1997). The method has been applied to a granite formation in France. Geological data on different families of fractures have been used for the statistical representation of the fractures. A mesh-generating tool for the medium with high density of fractures has been developed. The mechanical behaviour of the rock mass (elasticity, ultimate strength and hardening law) has been determined assuming linear elasticity and Mohr,Coulomb strength criterion both for the intact rock and the fractures. Evolution of the mechanical strength in different directions has been determined as a function of the mean stress, thanks to various numerical simulations. The mechanical strength appears to be anisotropic due to the preferential orientation of the fractures. The numerical results allowed us to determine an oriented strength criterion for the homogenized rock mass. A 2D constitutive law for the homogenized medium has been deduced from numerical data. A 3D extension of this model is also presented. Copyright © 2001 John Wiley & Sons, Ltd. [source]


Modelling the structural behaviour of a dam affected by alkali,silica reaction

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 1 2006
Eduardo M. R. Fairbairn
Abstract In this work we present an alkali,silica reaction (ASR) thermo-chemo-mechanical expansion model, whose main feature is to represent the stress-induced anisotropy by means of a classical smeared cracking model. This model considers the influence of temperature and humidity in the development of ASR. Since cracking occurs generally at the beginning of the swelling process, it is suggested that the assessment of the reaction characteristics in free expansion tests could be attained considering a cracked specimen. Hence, an inverse analysis is used to determine ASR parameters. The model was applied to the 3D simulation of alkali,silica expansion in a real gravity dam. We computed the displacements at the crest of the block comparing it with measures taken in situ for the last 25 years. The good correlation between experimental and numerical data displays the accuracy of the model, indicating its potentialities for engineering applications. Copyright © 2005 John Wiley & Sons, Ltd. [source]


A Cartesian grid technique based on one-dimensional integrated radial basis function networks for natural convection in concentric annuli

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 12 2008
N. Mai-Duy
Abstract This paper reports a radial basis function (RBF)-based Cartesian grid technique for the simulation of two-dimensional buoyancy-driven flow in concentric annuli. The continuity and momentum equations are represented in the equivalent stream function formulation that reduces the number of equations from three to one, but involves higher-order derivatives. The present technique uses a Cartesian grid to discretize the problem domain. Along a grid line, one-dimensional integrated RBF networks (1D-IRBFNs) are employed to represent the field variables. The capability of 1D-IRBFNs to handle unstructured points with accuracy is exploited to describe non-rectangular boundaries in a Cartesian grid, while the method's ability to avoid the reduction of convergence rate caused by differentiation is instrumental in improving the quality of the approximation of higher-order derivatives. The method is applied to simulate thermally driven flows in annuli between two circular cylinders and between an outer square cylinder and an inner circular cylinder. High Rayleigh number solutions are achieved and they are in good agreement with previously published numerical data. Copyright © 2007 John Wiley & Sons, Ltd. [source]


Large eddy simulation of turbulent flows via domain decomposition techniques.

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 4 2005
Part 2: applications
Abstract The present paper discusses the application of large eddy simulation to incompressible turbulent flows in complex geometries. Algorithmic developments concerning the flow solver were provided in the companion paper (Int. J. Numer. Meth. Fluids, 2003; submitted), which addressed the development and validation of a multi-domain kernel suitable for the integration of the elliptic partial differential equations arising from the fractional step procedure applied to the incompressible Navier,Stokes equations. Numerical results for several test problems are compared to reference experimental and numerical data to demonstrate the potential of the method. Copyright © 2005 John Wiley & Sons, Ltd. [source]


Steady/unsteady aerodynamic analysis of wings at subsonic, sonic and supersonic Mach numbers using a 3D panel method

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 10 2003
Jeonghyun Cho
Abstract This paper treats the kernel function of an integral equation that relates a known or prescribed upwash distribution to an unknown lift distribution for a finite wing. The pressure kernel functions of the singular integral equation are summarized for all speed range in the Laplace transform domain. The sonic kernel function has been reduced to a form, which can be conveniently evaluated as a finite limit from both the subsonic and supersonic sides when the Mach number tends to one. Several examples are solved including rectangular wings, swept wings, a supersonic transport wing and a harmonically oscillating wing. Present results are given with other numerical data, showing continuous results through the unit Mach number. Computed results are in good agreement with other numerical results. Copyright © 2003 John Wiley & Sons, Ltd. [source]


Numerical method for calculation of the incompressible flow in general curvilinear co-ordinates with double staggered grid

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 12 2003
A. Shklyar
Abstract A solution methodology has been developed for incompressible flow in general curvilinear co-ordinates. Two staggered grids are used to discretize the physical domain. The first grid is a MAC quadrilateral mesh with pressure arranged at the centre and the Cartesian velocity components located at the middle of the sides of the mesh. The second grid is so displaced that its corners correspond to the centre of the first grid. In the second grid the pressure is placed at the corner of the first grid. The discretized mass and momentum conservation equations are derived on a control volume. The two pressure grid functions are coupled explicitly through the boundary conditions and implicitly through the velocity of the field. The introduction of these two grid functions avoids an averaging of pressure and velocity components when calculating terms that are generated in general curvilinear co-ordinates. The SIMPLE calculation procedure is extended to the present curvilinear co-ordinates with double grids. Application of the methodology is illustrated by calculation of well-known external and internal problems: viscous flow over a circular cylinder, with Reynolds numbers ranging from 10 to 40, and lid-driven flow in a cavity with inclined walls are examined. The numerical results are in close agreement with experimental results and other numerical data. Copyright © 2003 John Wiley & Sons, Ltd. [source]


Learning cooperative linguistic fuzzy rules using the best,worst ant system algorithm

INTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 4 2005
Jorge Casillas
Within the field of linguistic fuzzy modeling with fuzzy rule-based systems, the automatic derivation of the linguistic fuzzy rules from numerical data is an important task. In the last few years, a large number of contributions based on techniques such as neural networks and genetic algorithms have been proposed to face this problem. In this article, we introduce a novel approach to the fuzzy rule learning problem with ant colony optimization (ACO) algorithms. To do so, this learning task is formulated as a combinatorial optimization problem. Our learning process is based on the COR methodology proposed in previous works, which provides a search space that allows us to obtain fuzzy models with a good interpretability,accuracy trade-off. A specific ACO-based algorithm, the Best,Worst Ant System, is used for this purpose due to the good performance shown when solving other optimization problems. We analyze the behavior of the proposed method and compare it to other learning methods and search techniques when solving two real-world applications. The obtained results lead us to remark the good performance of our proposal in terms of interpretability, accuracy, and efficiency. © 2005 Wiley Periodicals, Inc. Int J Int Syst 20: 433,452, 2005. [source]


Representation of the subjective evaluation of the fabric hand using fuzzy techniques

INTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 3 2003
Xianyi Zeng
This article presents a fuzzy logic,based method for representing and analyzing results of subjective evaluation on the fabric hand given by experts in fashion or quality inspection. This method permits the generation of a quantitative criterion characterizing the quality of textile products and modeling relationships between the subjective fabric hand evaluation and objective numerical data measured on the Kawabata evaluation system (KES). © 2003 Wiley Periodicals, Inc. [source]


Calman,Hine reassessed: a survey of cancer network development in England, 1999,2000

JOURNAL OF EVALUATION IN CLINICAL PRACTICE, Issue 3 2002
Beth Kewell BA PhD
Abstract Rationale, aims and objectives,The paper assesses preliminary national data on the development of cancer care networks in England. Methods,In January 2000, a national postal survey was sent to lead clinicians at 36 cancer centres and associate centres. Respondents were asked to provide basic numerical data on the design of the network (i.e. its configuration), detailing how many units it encompassed, and whether the centre was a multiple or a single entity. Results,The survey highlighted national variations in the size and configuration of networks. The survey also highlighted tentative signs of shifts in clinical practice. The results showed that consultants at cancer centres and units were engaging in two forms of collaboration across centre,unit boundaries. Type 1 involved routine multidisciplinary team (MDT) outreach from centres to units, incorporating joint planning between clinicians at cancer centres and cancer units. Type 2 collaboration involved joint planning but also promoted joint centre and unit training and continuing professional development (CPD) programmes. Conclusions,In our estimation, both forms of collaboration represented early evidence of qualitative changes in medical working practices. Organizational changes within cancer services have moved swiftly since initial soundings were taken in 2000 and we update our initial commentary in the light of recent empirical data. The findings may be of wider significance to managers and health practitioners who are working towards the implementation of delivery network elsewhere in the UK National Health Service. [source]


The Effect of Repeated Physical Disturbance on Soft Tissue Decomposition,Are Taphonomic Studies an Accurate Reflection of Decomposition?,

JOURNAL OF FORENSIC SCIENCES, Issue 5 2007
Rachel E. Adlam M.Sc.
Abstract:, Although the relationship between decomposition and postmortem interval has been well studied, almost no studies examined the potential effects of physical disturbance occurring as a result of data collection procedures. This study compares physically disturbed rabbit carcasses with a series of undisturbed carcasses to assess the presence and magnitude of any effects resulting from repetitive disturbance. Decomposition was scored using visual assessment of soft tissue changes, and numerical data such as weight loss and carcass temperature were recorded. The effects of disturbance over time on weight loss, carcass temperature, soil pH and decomposition were studied. In addition, this study aimed to validate some of the anecdotal evidence regarding decomposition. Results indicate disturbance significantly inversely affects both weight loss and carcass temperature. No differences were apparent between groups for soil pH change or overall decomposition stage. An insect-mediated mechanism for the disturbance effect is suggested, along with indications as to why this effect may be cancelled when scoring overall decomposition. [source]


Integrating Reform-Oriented Math Instruction in Special Education Settings

LEARNING DISABILITIES RESEARCH & PRACTICE, Issue 2 2007
Brian A. Bottge
This mixed-methods study assessed the effects of Enhanced Anchored Instruction (EAI) on the math performance of adolescents with learning disabilities in math (MLD). A quasi-experimental pretest,posttest control group design with switching replications was used to measure students' computation and problem-solving skills on EAI compared to control conditions. Scores on the curriculum-aligned and standardized measures showed improved problem-solving skills but results were mixed for computation. To augment the numerical data, a qualitative inquiry captured day-to-day classroom activities. The findings showed that problem-based curricula such as EAI have the potential for helping students with MLD develop deeper understandings of math concepts but that considerable effort is required to structure and teach these concepts in ways students with MLD understand. [source]


Eigen-frequencies in thin elastic 3-D domains and Reissner,Mindlin plate models

MATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 1 2002
Monique Dauge
Abstract The eigen-frequencies of elastic three-dimensional thin plates are addressed and compared to the eigen-frequencies of two-dimensional Reissner,Mindlin plate models obtained by dimension reduction. The qualitative mathematical analysis is supported by quantitative numerical data obtained by the p-version finite element method. The mathematical analysis establishes an asymptotic expansion for the eigen-frequencies in power series of the thickness parameter. Such results are new for orthotropic materials and for the Reissner,Mindlin model. The 3-D and R,M asymptotics have a common first term but differ in their second terms. Numerical experiments for clamped plates show that for isotropic materials and relatively thin plates the Reissner,Mindlin eigen-frequencies provide a good approximation to the three-dimensional eigen-frequencies. However, for some anisotropic materials this is no longer the case, and relative errors of the order of 30 per cent are obtained even for relatively thin plates. Moreover, we showed that no shear correction factor is known to be optimal in the sense that it provides the best approximation of the R,M eigen-frequencies to their 3-D counterparts uniformly (for all relevant thicknesses range). Copyright © 2002 John Wiley & Sons, Ltd. [source]


22 Comparison of multichannel electrogastrograms obtained with the use of three different electrode types

NEUROGASTROENTEROLOGY & MOTILITY, Issue 6 2006
K JONDERKO
Background/Aims:, Multichannel recording of the gastric myoelectrical activity (GMA) is a promising evolution of electrogastrography. In the study we searched for electrodes the most suitable to obtain high quality multi-channel electrogastrograms. Methods:, Twelve young volunteers (9 F, 3 M, aged 24.3 ± 0.6 years) underwent on separate days three four-channel electrogastrographic recordings of the GMA: 30 min fasted and 90 min after a solid meal stimulation. The electrogastrograms were recorded in randomized order with 3M Red Dot class Ag/AgCl electrodes designed primarily for long-term electrocardiographic monitoring: type­2222 (conductive area, CA/total area, TA): 2.00/10.24 cm2, type­2271 2.54/29.64 cm2, type­2660 11.64/11.64 cm2 (total surface conductive!) and subsequently analysed with Polygram NetÔ EGG 311224 software (Medtronic, USA). Electrical resistance between active electrodes relative to the reference one was measured with a digital ohmmeter before and after the recording session. Results:, Type­2660 yielded consistently higher electrical resistance than the other electrode types, moreover in the case of type­2271 and type­2660 electrical conductivity significantly improved at the end of the recording relative to the basal measurement. Analysis of variance involving the relative time-share of normogastria, meal-induced change in dominant power, as well as a set of parameters unique for the multichannel electrogastrography and intended to characterize the so-called spatial displacement of the gastric slow waves did not reveal any statistically significant effect of the electrode type on the parameters of the multichannel electrogastrogram. Although, when particular numerical data were inspected, type­2271 was found to perform slightly worse than the other electrode types. Type­2271 was also rated the less handy among the electrodes tested. Conclusion:, Multichannel surface electrogastrography seems to be technically feasible with any type of high quality Ag/AgCl electrodes available on the market, whereas small dimensions enabling easy placement on the abdomen may be a feature favouring the choice of a particular electrode type for this examination. [source]


Non-linear dynamical effects in semiconductor microcavities

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 11 2005
J. L. Staehli
Abstract An investigation of the parametric amplification and its coherent control in a semiconductor microcavity is presented. The time and angle resolved pump and probe experiments show that several picoseconds after pumping the polaritons are still coherent and parametric scattering is still going on. The experimental data concerning the time integrated measurements are in qualitative agreement with the numerical data obtained from a relatively simple theoretical model based on three polarisation components, pump, probe, and idler. As for the dynamics of parametric amplification in real time, the measurements reveal that often stimulation is considerably delayed with respect to the arrival of pump and probe. Even though the observed dynamics is complex, our simple theoretical model permits to reproduce several of the experimental features. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


PHENIX: a comprehensive Python-based system for macromolecular structure solution

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 2 2010
Paul D. Adams
Macromolecular X-ray crystallography is routinely applied to understand biological processes at a molecular level. However, significant time and effort are still required to solve and complete many of these structures because of the need for manual interpretation of complex numerical data using many software packages and the repeated use of interactive three-dimensional graphics. PHENIX has been developed to provide a comprehensive system for macromolecular crystallographic structure solution with an emphasis on the automation of all procedures. This has relied on the development of algorithms that minimize or eliminate subjective input, the development of algorithms that automate procedures that are traditionally performed by hand and, finally, the development of a framework that allows a tight integration between the algorithms. [source]


Ein Bemessungsansatz für zweiachsig durch Querkräfte beanspruchte Stahlbetonbalken mit Rechteckquerschnitt

BETON- UND STAHLBETONBAU, Issue 5 2005
Peter Mark Dr.-Ing.
Für Stahlbetonbalken mit Rechteckquerschnitt und üblichen zweischnittigen Bügeln wird ein Ansatz zur Bemessung gegen geneigt zu den Hauptachsen einwirkende Querkräfte abgeleitet und an Simulationsrechnungen und Experimenten verifiziert. Der Ansatz basiert auf dem der DIN 1045-1 zugrunde liegenden "Fachwerkmodell mit Rißreibung" und ergänzt zur Berücksichtigung einer Querkraftneigung die Gleichungen der Querkraftwiderstände nach DIN 1045-1 durch einfache Faktoren aus Geometrie- und Lastgrößen. Ein Beispiel zeigt, daß die Widerstände merklich abnehmen bzw. höhere Bügelbewehrungsmengen erforderlich sind, falls die Querkraft von einer hauptachsenparallelen Wirkungsrichtung abweicht. Design of Reinforced Concrete Beams with rectangular Cross Sections against biaxial Shear Forces An approach is presented to design reinforced concrete beams with rectangular cross sections and usual stirrups against shear forces that act inclined to the principal axes of the cross sections. It basis on the "truss model with crack friction" and adds supplementary terms to the equations of the shear resistances acc. to DIN 1045-1 to take account for shear force inclinations. Verifications to experimental as well as numerical data are given. An example shows that resistances evidently decrease , or higher amounts of stirrup reinforcement become necessary ,, if shear forces deviate from principal axes. [source]


Exposure of non-target tissues in medical diathermy

BIOELECTROMAGNETICS, Issue 1 2010
N. Leitgeb
Abstract With different prevalence in different regions, radio frequency (RF) electromagnetic fields (EMF) are widely used for therapeutic tissue heating. Although short-wave diathermy (27.12,MHz) is the most popular treatment modality, quantitative data on patient's exposure have been lacking. By numerical simulation with the numerical anatomical model NORMAN, intracorporal distributions of specific absorption rates (SAR) were investigated for different treatment scenarios and applicators. Quantitative data are provided for exposures of target treatment areas as well as for vulnerable regions such as the eye lenses, central nervous system, and testes. Different applicators and distances were investigated. Capacitive and inductive applicators exhibit quite a different heating efficiency. It could be shown that for the same output power therapeutic heat deposition can vary by almost one order of magnitude. By mimicking therapist's practice to use patient's heat perception as an indicator for output power setting, numerical data were elaborated demonstrating that muscle tissue exposures may be several times higher for inductive than for capacitive applicators. Presented quantitative data serve as a guide for power adjustment preventing relevant overexposures without compromising therapy; they also provide a basis for estimating target tissue heat load and developing therapeutic guidelines. Bioelectromagnetics 31:12,19, 2010. © 2009 Wiley-Liss, Inc. [source]


1342: Communicating numerical results correctly

ACTA OPHTHALMOLOGICA, Issue 2010
T KIVELÄ
Purpose To highlight some pearls and pitfalls in reporting numerical data related to the eye with special reference to the instructions of the EVER Journal, Acta Ophthalmologica. Methods Personal experience of the author as a writer, reviewer and editorial board member is used to highlight common issues specific for reporting statistics. The rules and the reasoning behind them are explained using abundant real life examples. Results Statistics and mathematical analyses applied should be described in the methods section, but the software used need not be referenced unless it is specific for the test used. The following rules regarding reporting are highly recommended: 1. Report proportions if the number of subjects is smaller than 10; percentages in integers if the number of subjects is less than 100; if the number of subjects is larger, one decimal place can be given but is seldom necessary. 2. Report summary statistics of normally distributed variables as mean with standard deviation; other variables as medium with range. 3. Use parametric and nonparametric statistical tests accordingly. 4. Give exact p-values (e.g. p=0.034); if p-value is less than 0.001, report p<0.001. 5. Give 95% confidence intervals for main findings. 6. Mention the statistical test used with the p-value (e.g. p=0.015, paired t-test) if multiple methods are used. Conclusion Efficient reporting and analysis of data related to the eye is not difficult as long as one is aware of the basic rules. Putting them into action helps to ensure that the conclusions the readers draw from your study are proper. [source]


Mathematical determination of the numerical data corresponding to the color-matching functions of three real observers using the RGB CIE-1931 primary system and a new system of unreal primaries X,Y,Z,

COLOR RESEARCH & APPLICATION, Issue 2 2003
J. A. Martínez
Abstract In this work, we determine the numerical data of the experimental color-matching functions (cmf's) of three real observers (JAM, MM, and CF) for two small fields (2°). In previous works, these cmf's have been shown generically and expressed only in a new system of unreal X,Y,Z, primaries. Here, we show results found with these cmf's for the visible spectrum in intervals of 10 nm, from 400 to 700 nm. The data refer to both the RGB CIE-1931 system and a new system of unreal primaries X,Y,Z,, established by a procedure similar to that of the XYZ CIE-1931 system. This transformation was needed, because negative values appeared in various cmf's when they were referred to the XYZ CIE-1931 system. Recently, we have called this new system G94 (Granada ,94). Here, we also describe the method and calculation of the matrix that enables this transformation; in testing six real observers with new cmf's, we found positive results. We have used these new and experimental cmf's in several preceding works, as have other authors as well, to whom J. A. Martínez privately communicated the corresponding numerical data. The use of these cmf's by all the authors has led to noteworthy results. © 2003 Wiley Periodicals, Inc. Col Res Appl, 28, 89,95, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.10127 [source]