A STATISTICAL ANALYSIS OF SOME AEROMAGNETIC MAPS FROM THE NORTHWESTERN CANADIAN SHIELD

Geophysics ◽  
1964 ◽  
Vol 29 (4) ◽  
pp. 582-601 ◽  
Author(s):  
C. W. Horton ◽  
W. B. Hempkins ◽  
A. A. J. Hoffman

Autocovariance and power‐spectral techniques are applied to aeromagnetic maps from the District of MacKenzie, Northwest Territories, Canada, to obtain trend directions and other structural information. Such trends are representative of the geologic structures creating the magnetic anomalies, and they are subjected to structural analysis. Results of computations for four maps 17×17 miles in size and one profile 185 miles long show good agreement with the known geological structure of the region. These analyses predict a dominant structural trend from S 18° W to N 18° E and two associated conjugate shear directions. In addition, an unexplained basic periodicity with a wave length of 15 miles is shown. This type of statistical analysis is suggested as a new tool for the extension of geologic data into inaccessible or covered regions.

1993 ◽  
Vol 217 (3-4) ◽  
pp. 285-305 ◽  
Author(s):  
A.K. Goodacre ◽  
G.F. Bonham-Carter ◽  
F.P. Agterberg ◽  
D.F. Wright

2021 ◽  
Vol 20 (2) ◽  
pp. 99-106
Author(s):  
O.I. Popoola ◽  
O.A. Adenuga ◽  
E.O. Joshua

The geological map of the old western region of Nigeria indicates the presence of iron ore deposit at Iboro village Ogun state (7.9983o - 7.99933o N, 3.5790o - 3.5890o E). Hence a ground magnetic survey was carried out at a location at Iboro village so as to delineate the subsurface magnetic anomalies and to know whether the anomalies favour accumulation of magnetic minerals. The survey was carried out using high resolution proton precession magnetometer model G-856X. Eight traverses were run at 5m separations and earth magnetic intensity values were measured at 10m intervals along each traverse; the acquired data were corrected for drift. The residual anomalies obtained by removal of regional gradient from observed data using trend analysis were presented as profiles and maps. The treated data were qualitatively and quantitatively interpreted and the results gave values for the total ground magnetic anomalies that varied between a minimum and maximum peak values of about -33.0 and 30.6nT respectively. Depth to the basement rock was estimated using Peter’s half slope method which gave a maximum depth of about 13m. The contour maps and the total relative graphs present the subsurface picture of the geological structure that is assumed to harbour the metallic minerals through the action of the field towards the concentration of anomalies. It was suspected that the overburden was relatively thin in the study area and the minerals were at a shallow depth.


The first section of this paper is an account of some experiments on the absorption of light in sodium vapour from the series limit at 2412 Å to about 1600 Å (an energy difference of 2·6 eV). The absorption cross-section at the limit is 11·6 ± 1·2 x 10 -20 cm 2 . The cross-section decreases giving a minimum of 1·3 ± 0·6 x 10 -20 cm 2 at 1900 Å and then increases to 1600 Å. A theoretical calculation by Seaton based on the dipole-length formula gives good agreement with the experiments at the series limit and also correctly predicts the wave-length for the minimum, but it predicts a significantly lower absorption at the minimum. The experiments described in the first section of the paper conclude a series on the absorption of light in the alkali metals. The second section consists of a general discussion of the results of these experiments and of their relation to theoretical calculations. There is good agreement between theory and experiment except in regard to the magnitude of the absorption at the minimum.


2020 ◽  
Vol 21 (2) ◽  
pp. 121-125
Author(s):  
Vesna Ignjatovic ◽  
Milovan Matovic ◽  
Vladimir Vukomanovic

AbstractCirculating thyroglobulin measurements is a highly specific test in the management of patients affected by differentiated thyroid cancer after total thyroidectomy, followed by radioiodine ablation. The aim of our study was to compare two thyroglobulinimmunoradiometric assays (INEP, Serbia and Cisbio Bioassays, France). Study included 42 patients of both genders with DTC. The subjects were on suppres¬sive doses of levothyroxine and followed up. Results showed concordance between the two assay methods for determining serum thyroglobulin for 39 (92.85%) patients. Statistical analysis showed that there was a direct correlation between two IRMA tests, with a positive correlation coefficient r=0.613 (p 0.05). We concluded that there is good agreement between the two thyroglobulin assays compared in this study.


2011 ◽  
Vol 26 (2) ◽  
pp. 236-242 ◽  
Author(s):  
A. F. Stein ◽  
Y. Wang ◽  
J. D. de la Rosa ◽  
A. M. Sanchez de la Campa ◽  
Nuria Castell ◽  
...  

Abstract The Hybrid Single-Particle Lagrangian Integrated Trajectories (HYSPLIT) model has been applied to calculate the spatial and temporal distributions of dust originating from North Africa. The model has been configured to forecast hourly particulate matter ≤10 μm (PM10) dust concentrations focusing on the impacts over the southern Iberian Peninsula. Two full years (2008 and 2009) have been simulated and compared against surface background measurement sites. A statistical analysis using discrete and categorical evaluations is presented. The model is capable of simulating the occurrence of Saharan dust episodes as observed at the measurement stations and captures the generally higher levels observed in eastern Andalusia, Spain, with respect to the western Andalusia station. But the simulation tends to underpredict the magnitude of the dust concentration peaks. The model has also been qualitatively compared with satellite data, showing generally good agreement in the spatial distribution of the dust column.


2009 ◽  
Vol 5 (S265) ◽  
pp. 354-355
Author(s):  
Oscar Cavichia ◽  
Roberto D. D. Costa ◽  
Walter J. Maciel

AbstractNew abundances of planetary nebulae located towards the bulge of the Galaxy are derived based on observations made at LNA (Brazil). We present accurate abundances of the elements He, N, S, O, Ar, and Ne for 56 PNe located towards the galactic bulge. The data shows a good agreement with other results in the literature, in the sense that the distribution of the abundances is similar to those works. From the statistical analysis performed, we can suggest a bulge-disk interface at 2.2 kpc for the intermediate mass population, marking therefore the outer border of the bulge and inner border of the disk.


1978 ◽  
Vol 24 (10) ◽  
pp. 1836-1837 ◽  
Author(s):  
N B Roberts

Abstract The mechanized measurement of inorganic phosphate in plasma can be achieved without reduction by only minor alterations to an existing continuous-flow reduction procedure. The method is based on the enhancement of the extinction of the phosphomolybdate complex by the detergent Triton X-100. Results obtained agree well with those obtained by the standard reduction (Fiske-SubbaRow) procedure. The correlation coefficient between the two methods was 0.996 and statistical analysis of the data confirmed very good agreement between the two sets of values.


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