New Aeromagnetic Survey Results on a Barents Sea Section

Author(s):  
Yu.G. Turbin ◽  
A.A. Petrova
2014 ◽  
Author(s):  
Jean M. Legault* ◽  
Shengkai Zhao ◽  
Nasreddine Bournas ◽  
Geoffrey Plastow ◽  
Gillian Kearvell

2003 ◽  
Vol 60 (5) ◽  
pp. 967-979 ◽  
Author(s):  
Vidar Hjellvik ◽  
Kathrine Michalsen ◽  
Asgeir Aglen ◽  
Odd Nakken

Abstract For species like cod and haddock, commonly distributed from bottom to far above bottom, swept area (bottom trawl) indices and acoustic indices of abundance cover different fractions of the stock. It has been argued that a combination of the two density estimates, into one estimate of absolute abundance, will improve the reliability of the survey results. The effective fishing height of the trawl may not be equal to the headline height of the trawl. In response to vessel noise, fish in the pelagic zone may swim towards the bottom. The bottom trawl will thus catch fish higher in the water column than the height of the trawl opening. Vertical herding is highly dependent on the size of the fish and their vertical distribution pattern. In this paper, bottom-trawl-catches and acoustic recordings of northeast Arctic cod, from annual surveys conducted in the Barents Sea seasonally over the past few years, have been compared. Differences in the relationship between the two methods are discussed regarding fish length, time of day, season, year, vertical distribution, and depth. Only “clean” stations, with regard to species and length distribution, were used in the analysis. In order to combine the swept area and acoustic estimates the effective catch height of the bottom trawl must be known. Therefore, the catchability of the trawl as a function of height above bottom has been estimated for three different length groups by fitting a logistic model to the data and by examining patterns in the correlation between trawl catches and acoustic densities. The results were equivocal.


Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 665
Author(s):  
Bona Kim ◽  
Soocheol Jeong ◽  
Eunseok Bang ◽  
Seungwook Shin ◽  
Seongjun Cho

We present our aeromagnetic survey results from an investigation of the iron ore mineral distribution in Pocheon, Korea, in the west-central area of the Korean Peninsula. A manned aeromagnetic system using a helicopter for regional exploration and an unmanned aeromagnetic system using a multicopter for high-resolution exploration were used for the survey. The inversion results of the magnetic data confirmed the possibility of the existence of a new iron ore body. Drilling was carried out based on inversion results and drilling revealed amphibolite including iron ore, as indicated by a strong magnetic response. The position and depth of the iron ore were consistent with the interpretation results of the magnetic data.


2020 ◽  
Vol 224 (2) ◽  
pp. 1422-1428
Author(s):  
M-A Dumais ◽  
L Gernigon ◽  
O Olesen ◽  
S E Johansen ◽  
M Brönner

SUMMARY Insights into the spreading evolution of the Knipovich Ridge and development of the Fram Strait are revealed from a recent aeromagnetic survey. As an ultraslow spreading ridge in an oblique system located between the Svalbard–Barents Sea and the Northeast Greenland rifted margins, the dynamics of the Knipovich Ridge opening has long been debated. Its 90° bend with the Mohns Ridge, rare in plate tectonics, affects the evolution of the Fram Strait and motivates the study of crustal deformation with this distinctive configuration. We identified magnetic isochrons on either side of the present-day Knipovich Ridge. These magnetic observations considerably reduce the mapped extent of the oceanic domain and question the present understanding of the conjugate rifted margins. Our analysis reveals a failed spreading system before a major spreading reorganization of the Fram Strait gateway around magnetic chron C6 (circa 20 Ma).


Geophysics ◽  
1961 ◽  
Vol 26 (2) ◽  
pp. 211-228 ◽  
Author(s):  
K. Whitham ◽  
E. R. Niblett

Errors introduced into aeromagnetic survey results because of geomagnetic time variations have been analyzed in two ways. In the first, statistical properties of average magnetic disturbance have been calculated for five locations well distributed in latitude in Canada. The autocorrelation functions of vertical magnetic field fluctuations have been used to estimate errors in aeromagnetic surveying as a function of the length of the base loop and the length of the traverse lines or profiles, for five latitudes. In practical applications, the r.m.s. errors are proportional to the square root of elapsed time. These results can be explained in terms of the shape of the autocorrelation functions, and models of disturbance which might produce them are discussed. In the second part experimental results are presented of a comparison of total field intensity fluctuations measured with recording proton precession magnetometers at two pairs of stations, one pair 26 miles apart and the other 94 miles apart. The measurements were taken in Western Canada south of the auroral zone. The r.m.s. differences in the time variations have been determined quantitatively for each hour for both pairs of stations; statistically, it was found that these differences were proportional to the r.m.s. level of magnetic activity and, in this region, to the separation of the stations. The frequency distributions of the r.m.s. differences between the two pairs of stations for the month of September 1959 have been determined. A comparison of the indirect and direct methods of correction indicates that scientifically, in this region, there is little to choose between them in terms of accuracy. Operational considerations are mentioned.


2020 ◽  
Vol 29 (2) ◽  
pp. 290-299
Author(s):  
Julie G. Arenberg ◽  
Ray H. Hull ◽  
Lisa Hunter

Purpose From the Audiology Education Summit held in 2017, several working groups were formed to explore ideas about improving the quality and consistency in graduate education in audiology and externship training. The results are described here from one of the working groups formed to examine postgraduate specialization fellowships. Method Over the course of a year, the committee designed and implemented two surveys: one directed toward faculty and one toward students. The rationale for the survey and the results are presented. Comparisons between faculty and student responses are made for similar questions. Results Overall, the results demonstrate that the majority of both students and faculty believe that postgraduation specialization fellowships are needed for either 1 year or a flexible length. There was a consensus of opinion that the fellowship should be paid, as these would be designed for licensed audiologists. Most believed that the fellowships should be “governed by a professional organization (e.g., American Speech-Language-Hearing Association, American Academy of Audiology, American Doctors of Audiology, etc.),” or less so, a “separate body for this specific purpose.” Potential topics for specialization identified were the following: tinnitus, vestibular, cochlear implants, pediatrics, and intraoperative monitoring. The highest priority attributes for a specialization site were “abundant access to patient populations,” “staff of clinical experts,” and “active research.” The weight put toward these attributes differed between faculty and students with faculty prioritizing “university/academic centers,” and “access to academic coursework in the fellowship area.” The faculty rated “caseload diversity,” “minimum hours,” “research,” and “academic affiliation” as requirements for a fellowship site, with less weight for “coursework” and “other.” Finally, the students valued “improved personal ability to provide exceptional patient care,” “the potential for increased job opportunities,” and the “potential for a higher salary” as benefits most important to them, with lower ratings for “recognition as a subject matter expert” or “potential pathway to Ph.D. program.” Conclusions As a result of the survey, further exploration of a postgraduate specialization fellowship is warranted, especially to determine funding opportunities to offset cost for the sites and to ensure that fellows are paid adequately.


2010 ◽  
Vol 19 (4) ◽  
pp. 100-107 ◽  
Author(s):  
Lindsay Kessel ◽  
Linda Sue Sickman

Abstract This study describes survey results measuring the knowledge undergraduate elementary education major students have about augmentative and alternative communication. Those students with experience and course knowledge surrounding AAC were more knowledgeable. Implications for speech-language pathologists (SLPs) will be addressed, including how SLPs can provide classroom teachers with classroom support for general education teachers.


ASHA Leader ◽  
2011 ◽  
Vol 16 (12) ◽  
pp. 22-23
Author(s):  
Amy Hasselkus
Keyword(s):  

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