Frequency-magnitude-time relationships in the NGSDC earthquake data file

1979 ◽  
Vol 69 (6) ◽  
pp. 2085-2099
Author(s):  
E. D. Bloom ◽  
R. C. Erdmann
Keyword(s):  
Statistical Analysis ◽  
Data Base ◽  
Accurate Determination ◽  
Data File ◽  
Event Magnitude ◽  
Frequency Magnitude ◽  
Earthquake Data

abstract In performing a statistical analysis of the NGSDC data base, we have found completeness problems in time and magnitude which can affect the accurate determination of derivative frequency-magnitude relations. Techniques are suggested which may circumvent most inaccuracies. In particular, the choice of event magnitude is important in minimizing distortion in frequency-magnitude relations. A new working magnitude, M3, is suggested as useful for the NGSDC data base, where M 3 = [ M S , if it is present Max ( m b , M L , M u ) , m b < 6 , M S is not present Max [ ( 2 . 0 m b − 5.4 ) , M L , M u ] , m b ≧ 6 , M S is not present . After correcting for time bias the use of M3 reduces distortion of frequency-magnitude distributions derived from the NGSDC data base as compared to previous magnitude definitions used.

Analysis of Sulfites in Shrimp Using Rapid Distillation Followed by Redox Titration1

1988 ◽  
Vol 51 (2) ◽  
pp. 137-138 ◽  
Author(s):  
MARIAN V. SIMPSON ◽  
W. STEVEN OTWELL ◽  
MAURICE R. MARSHALL ◽  
JOHN A. CORNELL
Keyword(s):  
Statistical Analysis ◽  
Steam Distillation ◽  
Accurate Determination ◽  
T Test ◽  
Distillation Method ◽  
Student’S T ◽  
Student’S T Test

The use of rapid steam distillation followed by redox iodine titration provides a rapid and accurate determination of total sufite residual in shrimp. Values obtained for sulfite-treated shrimp using the rapid distillation method gave comparable results to those of the officially recognized Monier-Williams method. Values for the rapid distillation method ranged from 6 to 212 ppm while those of the Monier-Williams procedure ranged from 6 to 241 ppm for untreated and treated shrimps, respectively. Statistical analysis using two-sample Student's t-test indicated that there were no significant differences (p>0.05) for residual levels below 100 ppm but the values obtained by the rapid distillation method and the Monier-Williams procedure were significantly different (p<0.05) at concentrations near and above 100 ppm.

A STUDY OF THE HOMOGENEITY OF THE NOAA EARTHQUAKE DATA FILE IN THE MID-AMERICA REGION BY THE MAGNITUDE SIGNATURE TECHNIQUE

1989 ◽  
Vol 28 (1) ◽  
pp. 103-119
Author(s):  
F. R. Zuñiga
Keyword(s):  
Data File ◽  
Earthquake Data ◽  
Preliminary Determination

El archivo de datos de sismicidad compilado por la N.O.A.A. (National Oceanic and Atmospheric Administration) de los Estados Unidos conocido como "Earthquake Data File" o EDF, contiene información que puede ser de gran importancia cuando se va a estudiar la sismicidad de alguna región del mundo en particular. Sin embargo, la homogeneidad de este catálogo, el cual básicamente está formado por datos recabados por P.D.E. (Preliminary Determination of Epicenters), depende de las características de las estaciones y agencies que proporcionaron los datos originalmente.El motivo de estudio del presente trabajo es el análisis de la homogeneidad del catálogo de la NOAA, específicamente para la región de Meso-América. Se emplea una técnica recientemente propuesta que permite simular cambios en los eventos reportados con respecto al tiempo. Estos cambios pueden presentarse tanto en el número como en las características de los eventos que constituyen el catálogo. El método empleado se describe brevemente. Los tiempos de ocurrencia de los cambios mencionados, obtenidos por la de la "firma de la magnitud", y sus probables causes, se determinan, y se proponen correcciones para eliminar las variaciones que pueden afectar la definición de la sismicidad de fondo.Los tiempos para los que se encontraron cambios, con suficiente significancia estadística, son: finales de septiembre de 1965; mediados de octubre de 1967 ; principios de octubre de 1969; finales de mayo de 1972, y finales de Junio de 1979. Las correcciones propuestas para los eventos listados en el catálogo son: la magnitud (mb) de los eventos de Julio de 1964 a septiembre de 1965 debe ser disminuida en 0.1 unidades; los eventos de septiembre de 1965 a mayo de 1972 deben ser corregidos añadiendo 0.1 unidades a las magnitudes listadas, y por último, los eventos posteriores a mayo de 1972 no deben ser corregidos.Con estos resultados se puede evitar la probable inclusión de cambios artificiales de sismicidad que pudieran de otra manera ser confundidos con variaciones reales. Así, el estudio de la sismicidad con fines de predicción en regiones de Meso-América podrá ser llevado a cabo con resultados más precisos.

A quantitative approach to inner shell losses

1978 ◽  
Vol 36 (1) ◽  
pp. 526-527 ◽  
Author(s):  
R.D. Leapman ◽  
P. Rez ◽  
D.F. Mayers
Keyword(s):  
Energy Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Accurate Determination ◽  
Background Intensity ◽  
Core Excitation ◽  
Quantitative Basis ◽  
Cross Section Differential ◽  
Bound Electrons

Microanalysis by EELS has been developing rapidly and though the general form of the spectrum is now understood there is a need to put the technique on a more quantitative basis (1,2). Certain aspects important for microanalysis include: (i) accurate determination of the partial cross sections, σx(α,ΔE) for core excitation when scattering lies inside collection angle a and energy range ΔE above the edge, (ii) behavior of the background intensity due to excitation of less strongly bound electrons, necessary for extrapolation beneath the signal of interest, (iii) departures from the simple hydrogenic K-edge seen in L and M losses, effecting σx and complicating microanalysis. Such problems might be approached empirically but here we describe how computation can elucidate the spectrum shape.The inelastic cross section differential with respect to energy transfer E and momentum transfer q for electrons of energy E0 and velocity v can be written as

Fast calibration of CBED patterns for quantitative analysis

1993 ◽  
Vol 51 ◽  
pp. 674-675
Author(s):  
M.A. Gribelyuk ◽  
M. Rühle
Keyword(s):  
Reciprocal Lattice ◽  
Accurate Determination ◽  
Incident Beam ◽  
Crystal Thickness ◽  
Structure Model ◽  
Beam Direction ◽  
Transmitted Beam ◽  
Reciprocal Vector ◽  
On Line

A new method is suggested for the accurate determination of the incident beam direction K, crystal thickness t and the coordinates of the basic reciprocal lattice vectors V1 and V2 (Fig. 1) of the ZOLZ plans in pixels of the digitized 2-D CBED pattern. For a given structure model and some estimated values Vest and Kest of some point O in the CBED pattern a set of line scans AkBk is chosen so that all the scans are located within CBED disks.The points on line scans AkBk are conjugate to those on A0B0 since they are shifted by the reciprocal vector gk with respect to each other. As many conjugate scans are considered as CBED disks fall into the energy filtered region of the experimental pattern. Electron intensities of the transmitted beam I0 and diffracted beams Igk for all points on conjugate scans are found as a function of crystal thickness t on the basis of the full dynamical calculation.

Computer-Assisted High-Re Solution TEM

1990 ◽  
Vol 48 (1) ◽  
pp. 162-163
Author(s):  
F.A. Ponce ◽  
H. Hikashi
Keyword(s):  
Signal To Noise Ratio ◽  
Accurate Determination ◽  
Computer Software ◽  
Video Camera ◽  
Image Contrast ◽  
Objective Lens ◽  
Computer Assisted ◽  
Optical Parameters ◽  
Astigmatism Correction

The determination of the atomic positions from HRTEM micrographs is only possible if the optical parameters are known to a certain accuracy, and reliable through-focus series are available to match the experimental images with calculated images of possible atomic models. The main limitation in interpreting images at the atomic level is the knowledge of the optical parameters such as beam alignment, astigmatism correction and defocus value. Under ordinary conditions, the uncertainty in these values is sufficiently large to prevent the accurate determination of the atomic positions. Therefore, in order to achieve the resolution power of the microscope (under 0.2nm) it is necessary to take extraordinary measures. The use of on line computers has been proposed [e.g.: 2-5] and used with certain amount of success.We have built a system that can perform operations in the range of one frame stored and analyzed per second. A schematic diagram of the system is shown in figure 1. A JEOL 4000EX microscope equipped with an external computer interface is directly linked to a SUN-3 computer. All electrical parameters in the microscope can be changed via this interface by the use of a set of commands. The image is received from a video camera. A commercial image processor improves the signal-to-noise ratio by recursively averaging with a time constant, usually set at 0.25 sec. The computer software is based on a multi-window system and is entirely mouse-driven. All operations can be performed by clicking the mouse on the appropiate windows and buttons. This capability leads to extreme friendliness, ease of operation, and high operator speeds. Image analysis can be done in various ways. Here, we have measured the image contrast and used it to optimize certain parameters. The system is designed to have instant access to: (a) x- and y- alignment coils, (b) x- and y- astigmatism correction coils, and (c) objective lens current. The algorithm is shown in figure 2. Figure 3 shows an example taken from a thin CdTe crystal. The image contrast is displayed for changing objective lens current (defocus value). The display is calibrated in angstroms. Images are stored on the disk and are accessible by clicking the data points in the graph. Some of the frame-store images are displayed in Fig. 4.

Maintenance of a Genetic Data Set on Multiple Data Base and Statistical Analysis Systems

1982 ◽  
Vol 61 (s109) ◽  
pp. 34-34
Author(s):  
Samuel J. Agronow ◽  
Federico C. Mariona ◽  
Frederick C. Koppitch ◽  
Kazutoshi Mayeda
Keyword(s):  
Statistical Analysis ◽  
Data Base ◽  
Genetic Data ◽  
Data Set ◽  
Multiple Data
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