Precision of measurement of remanent magnetization

1981 ◽  
Vol 18 (3) ◽  
pp. 527-538 ◽  
Author(s):  
J. C. Briden ◽  
G. R. Arthur
Keyword(s):  
Remanent Magnetization ◽  
Confidence Limits ◽  
Imprecise Data ◽  
Sensitivity Limit ◽  
Magnetization Measurements ◽  
Cartesian Component ◽  
The Difference ◽  
Test For Randomness

Confidence limits on the magnitude and direction of remanent magnetization measurements are derived as[Formula: see text]and[Formula: see text]where[Formula: see text]p is probability; n is the number of unbiased independent measurements Xi, Yi, Zi, of each Cartesian component x, y, z, and [Formula: see text] is the calculated magnitude of the remanence. Comparable expressions are derived for the confidence limits on the difference between two vectors. An approximate test for randomness is described. The errors commonly amount to more than 2% in magnitude and 2° in direction, and are greater for inhomogeneously magnetized samples and for vector magnitudes close to the sensitivity limit of the magnetometer. The effect of inhomogeneity of remanence requires special attention for most magnetometers. Applications of the methods to elimination of imprecise data, and assessing whether data conform to particular directional and stability-spectra models, are described.

Anaerobic Speed Reserve: A Key Component of Elite Male 800-m Running

2019 ◽  
Vol 14 (4) ◽  
pp. 501-508 ◽  
Author(s):  
Gareth N. Sandford ◽  
Sian V. Allen ◽  
Andrew E. Kilding ◽  
Angus Ross ◽  
Paul B. Laursen
Keyword(s):  
Confidence Limits ◽  
Performance Time ◽  
Maximal Aerobic Speed ◽  
Practical Tool ◽  
Individualized Training ◽  
The Difference ◽  
Performance Times ◽  
Negative Relationships ◽  
Reserve Ratio ◽  
Race Performance

Purpose: In recent years (2011–2016), men’s 800-m championship running performances have required greater speed than previous eras (2000–2009). The “anaerobic speed reserve” (ASR) may be a key differentiator of this performance, but profiles of elite 800-m runners and their relationship to performance time have yet to be determined. Methods: The ASR—determined as the difference between maximal sprint speed (MSS) and predicted maximal aerobic speed (MAS)—of 19 elite 800- and 1500-m runners was assessed using 50-m sprint and 1500-m race performance times. Profiles of 3 athlete subgroups were examined using cluster analysis and the speed reserve ratio (SRR), defined as MSS/MAS. Results: For the same MAS, MSS and ASR showed very large negative (both r = −.74 ± .30, ±90% confidence limits; very likely) relationships with 800-m performance time. In contrast, for the same MSS, ASR and MAS had small negative relationships (both r = −.16 ± .54; possibly) with 800-m performance. ASR, 800-m personal best, and SRR best defined the 3 subgroups along a continuum of 800-m runners, with SRR values as follows: 400–800 m ≥ 1.58, 800 m ≤ 1.57 to ≥ 1.48, and 800–1500 m ≤ 1.47 to ≥ 1.36. Conclusion: MSS had the strongest relationship with 800-m performance, whereby for the same MSS, MAS and ASR showed only small relationships to differences in 800-m time. Furthermore, the findings support the coaching observation of three 800-m subgroups, with the SRR potentially representing a useful and practical tool for identifying an athlete’s 800-m profile. Future investigations should consider the SRR framework and its application for individualized training approaches in this event.

Paleomagnetism and U–Pb geochronology of the Clarence Head dykes, Arctic Canada: orthogonal emplacement of mafic dykes in a large igneous province

2009 ◽  
Vol 46 (3) ◽  
pp. 155-167 ◽  
Author(s):  
Steven W. Denyszyn ◽  
Don W. Davis ◽  
Henry C. Halls
Keyword(s):  
Remanent Magnetization ◽  
High Arctic ◽  
Large Igneous Province ◽  
Dyke Swarm ◽  
Canadian High Arctic ◽  
The North ◽  
Igneous Province ◽  
The Difference ◽  
Age Range ◽  
Chemical Remanent Magnetization

The north–south-trending Clarence Head dyke swarm, located on Devon and Ellesmere Islands in the Canadian High Arctic, has a trend orthogonal to that of the Neoproterozoic Franklin swarm that surrounds it. The Clarence Head dykes are dated by the U–Pb method on baddeleyite to between 716 ± 1 and 713 ± 1 Ma, ages apparently younger than, but within the published age range of, the Franklin dykes. Alpha recoil in baddeleyite is considered as a possible explanation for the difference in ages, but a comparison of the U–Pb ages of grains of equal size from both swarms suggests that recoil distances in baddeleyite are lower than those in zircon and that the Clarence Head dykes are indeed a distinctly younger event within the period of Franklin magmatism. The Clarence Head dykes represent a large swarm tangential to, and cogenetic with, a giant radiating dyke swarm ∼800 km from the indicated source. The preferred mechanism for the emplacement of the Clarence Head dykes is the exploitation of concentric zones of extension around a depleting and collapsing plume source. While the paleomagnetism of most Clarence Head dykes agrees with that of the Franklin dykes, two dykes have anomalous remanence directions, interpreted to be a chemical remanent magnetization carried by pyrrhotite. The pyrrhotite was likely deposited from fluids mobilized southward from the Devonian Ellesmerian Orogeny to the north that used the interiors of the dykes as conduits and precipitated pyrrhotite en route.

scholarly journals Tracing of traffic-related pollution using magnetic properties of topsoils in Daejeon, Korea

2020 ◽  
Vol 79 (20) ◽  
Author(s):  
Seungwoo Lee ◽  
Seoyeon Kim ◽  
Hyeji Kim ◽  
Youlee Seo ◽  
Yeoncheol Ha ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Remanent Magnetization ◽  
Coarse Grained ◽  
Morphological Observation ◽  
Exhaust Emission ◽  
Thermal Demagnetization ◽  
Main Street ◽  
Traffic Related Pollution ◽  
The Difference

Abstract The present study was designed to explore the possibility of roadside pollution screening using magnetic properties of topsoil samples in Daejeon, South Korea. Low-field magnetic susceptibility, frequency dependence of magnetic susceptibility, susceptibility of anhysteretic remanent magnetization, isothermal remanent magnetization (IRM) acquisition and demagnetization, back-field IRM treatment, and thermal demagnetization of composite IRM were determined for roadside topsoil samples. Magnetic susceptibility measured on 238 samples from the upper 5 cm of the topsoils ranged from 8.6 to 82.5 × 10–5 SI with a mean of 28.3 ± 10.8 × 10–5 SI. The proximal zone, 55 m wide area situated on either side of the main street, exhibited an enhancement of magnetic susceptibility. In areas distant from the main street, low magnetic susceptibility (< 50 × 10–5 SI) was observed. The topsoil samples exhibited significant susceptibility contrasts, suggesting that two dimensional magnetic mapping was effective in identifying traffic-related pollution. A few magnetic hotspots with intensities of magnetic susceptibility near or over 50 × 10–5 SI might reflect the difference in topographic elevation and surface morphology. Among various IRM-related parameters, remanence of coercivity was most significant statistically. In most samples, IRM component analysis provided dual coercivity components. Thermal demagnetization of composite IRM and morphological observation of magnetic separates suggest angular magnetite produced by vehicle non-exhaust emissions spherical magnetite derived from exhaust emission to be the dominant contributors to the magnetic signal. It is likely that lower- and higher-coercivity components represent the presence of coarse-grained angular magnetite and fine-grained spherical magnetite, respectively.

scholarly journals On the credibility of remanent magnetization measurements

1980 ◽  
Vol 60 (3) ◽  
pp. 493-496 ◽  
Author(s):  
W. Lowrie ◽  
J. E. T. Channell ◽  
F. Heller
Keyword(s):  
Remanent Magnetization ◽  
Magnetization Measurements

Is Initial (24 Hours) Lavage Necessary in Treatment of CAPD Peritonitis?

1991 ◽  
Vol 11 (1) ◽  
pp. 38-42 ◽  
Author(s):  
Ellen Ejlersen ◽  
Lisbet Brandi ◽  
Hans Løkkegaard ◽  
Jørgen Ladefoged ◽  
Rena Kopp ◽  
...  
Keyword(s):  
Randomized Trial ◽  
Cell Count ◽  
Success Rate ◽  
Clinical Benefit ◽  
White Cell Count ◽  
Treatment Success ◽  
Confidence Limits ◽  
Acute Peritonitis ◽  
Profound Hypotension ◽  
The Difference

A randomized trial was conducted to examine the influence of initiallavage on treatment of CAPD peritonitis. Patients with hypotension and shock were excluded from the trial. Thirty -six CAPD patients with acute peritonitis were randomized to treatment with intraperitoneal antibiotics including either initial24 hours lavage before resumption of routine CAPD schedule (prior standard approach) or continued prolonged exchanges as in routine CAPD schedule. Median time to solved infection (normalization of white cell count in dialysis effluent) was identical (3 days) in the two groups. Treatment success rate was found to be 72% in the group with initial lavage and 89% in the group with prolonged exchanges. The difference in treatment success (17%) in favour of continued CAPD schedule was not found significant (95% confidence limits −1% to 35%). The results suggest lavage to be of no clinical benefit in treatment of CAPD peritonitis in patients without profound hypotension and shock.

scholarly journals Competitive Performance, Training Load and Physiological Responses During Tapering in Young Swimmers

2013 ◽  
Vol 38 ◽  
pp. 125-134 ◽  
Author(s):  
Argyris G. Toubekis ◽  
Evgenia Drosou ◽  
Vassilios Gourgoulis ◽  
Savvas Thomaidis ◽  
Helen Douda ◽  
...  
Keyword(s):  
Effect Size ◽  
Training Load ◽  
Confidence Limits ◽  
Competitive Performance ◽  
Performance Training ◽  
Performance Improvements ◽  
Hand Grip ◽  
Baseline Test ◽  
The Difference ◽  
And Performance

Abstract The study examined the changes of training load and physiological parameters in relation to competitive performance during a period leading to a national championship. The training content of twelve swimmers (age: 14.2±1.3 yrs) was recorded four weeks before the national championship (two weeks of normal training and two weeks of the taper). The training load was calculated: i) by the swimmer’s session-RPE score (RPE-Load), ii) by the training intensity levels adjusted after a 7x200-m progressively increasing intensity test (LA-Load). Swimmers completed a 400- m submaximal intensity test, a 15 s tethered swimming and hand-grip strength measurements 34-35 (baseline: Test 1), 20-21 (before taper: Test 2) and 6-7 (Test 3) days before the national championship. Performance during the national championship was not significantly changed compared to season best (0.1±1.6%; 95% confidence limits: -0.9, 1.1%; Effect Size: 0.02, p=0.72) and compared to performance before the start of the two-week taper period (0.9±1.7%; 95% confidence limits: 0.3, 2.1%; Effect size: 0.12, p=0.09). No significant changes were observed in all measured physiological and performance related variables between Test 1, Test 2, and Test 3. Changes in RPE-Load (week-4 vs. week-1) were correlated with changes in performance (r=0.63, p=0.03) and the RPE-Load was correlated with the LALoad (r=0.80, p=0.01). The estimation of the session-RPE training load may be helpful for taper planning of young swimmers. Increasing the difference between the normal and last week of taper training load may facilitate performance improvements.

Fibrinogen In Liver Cirrhosis. Lack Of Correlation Between Soluble Fibrin Monomer Complexes And Fibrinopeptide A Levels

1981 ◽  
Author(s):  
S Coccheri ◽  
P M Mannucci ◽  
G Palareti ◽  
M Cattaneo ◽  
M Poggi ◽  
...  
Keyword(s):  
Liver Cirrhosis ◽  
Liver Biopsy ◽  
Half Life ◽  
Collaborative Study ◽  
Gel Filtration ◽  
Fibrinopeptide A ◽  
Confidence Limits ◽  
Parametric Test ◽  
Soluble Fibrin ◽  
The Difference

In this collaborative study we have investigated the coexistence of two different markers of fibrinogen to fibrin conversion in 19 patients with liver cirrhosis, confirmed with liver biopsy, and classified according to standardized criteria into 11 moderate and 8 severe cases. Sepharose gel filtration of plasma allowed separation of fibrinogen-like material (FLM) into high m.w. (HMWF), peak, and low m.w. (LMWF) fractions, quantitated as percent (w/w) of the total FLM eluted. FPA was assayed radioimmunologically.HMWF was markedly increased in the whole group of cirrhotics (av ± SD 10.4% ± 2.77) , and in both moderate and severe patients, vs controls (6.9% ± 1.39; n=16; p < 0.01 for each comparison). LMWF was moderately increased in patients (6.8% ± l.84) vs controls (5.3% ± 1.35; p < 0.05).FPA levels (controls: median (m) ng/ml 2.2; m confidence limits (mcl) 1.4-2.5; range (r) < 0.6 to 4.1) showed an increase in cirrhotics (m 2.8; mcl 2.64-3.35, r<0.6 to 94) but the difference was not statistically significant using a non-parametric test. However, in 6 out of 19 patients FPA values exceeded av ± 2 SD of controls (av ± SD 2.05 ± 1.15). No significant correlations were found between FPA and HMWF or LMWF levels.The lack of correlation between FPA and HMWF although possibly related to half-life differences, suggests that, besides thrombin effect, other mechanisms for excess formation and/or accumulation of HMWF, as dysproteinaemia, dys- fibrinogenaemia, or impaired clearance, should be considered.

Accuracy of W′ Recovery Kinetics in High Performance Cyclists—Modeling Intermittent Work Capacity

2018 ◽  
Vol 13 (6) ◽  
pp. 724-728 ◽  
Author(s):  
Jason C. Bartram ◽  
Dominic Thewlis ◽  
David T. Martin ◽  
Kevin I. Norton
Keyword(s):  
Recovery Rate ◽  
High Performance ◽  
Critical Power ◽  
Intermittent Exercise ◽  
Work Capacity ◽  
Confidence Limits ◽  
Volitional Exhaustion ◽  
The Difference ◽  
Effective Use ◽  
Elite Cyclists

Purpose: With knowledge of an individual’s critical power and W′, the SKIBA 2 model provides a framework with which to track W′ balance during intermittent high-intensity work bouts. There are fears that the time constant controlling the recovery rate of W′ (τW′) may require refinement to enable effective use in an elite population. Methods: Four elite endurance cyclists completed an array of intermittent exercise protocols to volitional exhaustion. Each protocol lasted approximately 3.5–6 min and featured a range of recovery intensities, set in relation to the athlete’s critical power (DCP). Using the framework of the SKIBA 2 model, the τW′ values were modified for each protocol to achieve an accurate W′ at volitional exhaustion. Modified τW′ values were compared with equivalent SKIBA 2 τW′ values to assess the difference in recovery rates for this population. Plotting modified τW′ values against DCP showed the adjusted relationship between work rate and recovery rate. Results: Comparing modified τW′ values against the SKIBA 2 τW′ values showed a negative bias of 112 (46) s (mean ± 95% confidence limits), suggesting that athletes recovered W′ faster than predicted by SKIBA 2 (P = .0001). The modified τW′–DCP relationship was best described by a power function: τW′ = 2287.2 × DCP–0.688 (R2 = .433). Conclusions: The current SKIBA 2 model is not appropriate for use in elite cyclists, as it underpredicts the recovery rate of W′. The modified τW′ equation presented will require validation but appears more appropriate for high-performance athletes. Individual τW′ relationships may be necessary to maximize the model’s validity.

scholarly journals Early Bactericidal Activity of Paromomycin (Aminosidine) in Patients with Smear-Positive Pulmonary Tuberculosis

2000 ◽  
Vol 44 (12) ◽  
pp. 3285-3287 ◽  
Author(s):  
P. R. Donald ◽  
F. A. Sirgel ◽  
T. P. Kanyok ◽  
L. H. Danziger ◽  
A. Venter ◽  
...  
Keyword(s):  
Pulmonary Tuberculosis ◽  
Bactericidal Activity ◽  
Dose Group ◽  
Multidrug Resistant ◽  
Cross Resistance ◽  
Confidence Limits ◽  
Resistant Tuberculosis ◽  
Multidrug Resistant Tuberculosis ◽  
Smear Positive Pulmonary Tuberculosis ◽  
The Difference

ABSTRACT The early bactericidal activity of the aminoglycoside paromomycin (aminosidine) in doses of 7.5 and 15 mg/kg of body weight was measured in 22 patients with previously untreated smear-positive pulmonary tuberculosis. The fall in log10 CFU per milliliter of sputum per day during the first 2 days of treatment for 7 patients receiving a paromomycin dosage of 7.5 mg/kg/day was 0.066, with a standard deviation (SD) of 0.216 and confidence limits from −0.134 to 0.266, and that for 15 patients receiving 15 mg/kg/day was 0.0924, with an SD of 0.140 and confidence limits from 0.015 to 0.170. The difference between the mean and zero was not significant for the 7.5-mg/kg dose group but was significant for the 15-mg/kg dose group (t = 2.55, P = 0.023). Since paromomycin has no cross-resistance with streptomycin and has no greater toxicity than other aminoglycosides, these results suggest that it has the potential to substitute for streptomycin in antituberculosis regimens and may be a particularly valuable addition to the drug armamentarium for the management of multidrug-resistant tuberculosis.

Sign in / Sign up

Export Citation Format

Share Document