scholarly journals Reconstruction of baryon fraction in intergalactic medium through dispersion measurements of fast radio bursts

2021 ◽  
Vol 503 (3) ◽  
pp. 4576-4580
Author(s):  
Ji-Ping Dai ◽  
Jun-Qing Xia
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Mass Fraction ◽  
Large Scale ◽  
Intergalactic Medium ◽  
Radio Bursts ◽  
Local Principle ◽  
Relative Standard ◽  
Baryon Mass ◽  
The Mean

ABSTRACT Fast radio bursts (FRBs) probe the total column density of free electrons in the intergalactic medium (IGM) along the path of propagation through the dispersion measures (DMs) that depend on the baryon mass fraction in the IGM, i.e. fIGM. In this letter, we investigate the large-scale clustering information of DMs to study the evolution of fIGM. When combining with the Planck 2018 measurements, we could give tight constraints on the evolution of fIGM(z) from about 104 FRBs with the intrinsic DM scatter of $30(1+z) \rm pc\, cm^{-3}$ spanning 80 per cent of the sky and redshift range z = 0–3. First, we consider the Taylor expansion of fIGM(z) up to second order, and find that the mean relative standard deviation σ(fIGM) ≡ 〈σ[fIGM(z)]/fIGM(z)〉 is about 6.7 per cent. In order to alleviate the dependence on fiducial model, we also adopt non-parametric methods in this work, the local principle component analysis. We obtain the consistent, but weaker constraints on the evolution of fIGM(z), namely the mean relative standard deviation σ(fIGM) is 21.4 per cent. With the forthcoming surveys, this could be a complimentary method to investigate the baryon mass fraction in the IGM.

scholarly journals Internal consistency of the Regional Brewer Calibration Centre for Europe triad during the period 2005–2016

2018 ◽  
Vol 11 (7) ◽  
pp. 4059-4072 ◽  
Author(s):  
Sergio Fabián León-Luis ◽  
Alberto Redondas ◽  
Virgilio Carreño ◽  
Javier López-Solano ◽  
Alberto Berjón ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Data Sets ◽  
Individual Values ◽  
Relative Standard ◽  
The World ◽  
The Mean ◽  
The Individual ◽  
Ozone Column

Abstract. Total ozone column measurements can be made using Brewer spectrophotometers, which are calibrated periodically in intercomparison campaigns with respect to a reference instrument. In 2003, the Regional Brewer Calibration Centre for Europe (RBCC-E) was established at the Izaña Atmospheric Research Center (Canary Islands, Spain), and since 2011 the RBCC-E has transferred its calibration based on the Langley method using travelling standard(s) that are wholly and independently calibrated at Izaña. This work is focused on reporting the consistency of the measurements of the RBCC-E triad (Brewer instruments #157, #183 and #185) made at the Izaña Atmospheric Observatory during the period 2005–2016. In order to study the long-term precision of the RBCC-E triad, it must be taken into account that each Brewer takes a large number of measurements every day and, hence, it becomes necessary to calculate a representative value of all of them. This value was calculated from two different methods previously used to study the long-term behaviour of the world reference triad (Toronto triad) and Arosa triad. Applying their procedures to the data from the RBCC-E triad allows the comparison of the three instruments. In daily averages, applying the procedure used for the world reference triad, the RBCC-E triad presents a relative standard deviation equal to σ = 0.41 %, which is calculated as the mean of the individual values for each Brewer (σ157 = 0.362 %, σ183 = 0.453 % and σ185 = 0.428 %). Alternatively, using the procedure used to analyse the Arosa triad, the RBCC-E presents a relative standard deviation of about σ = 0.5 %. In monthly averages, the method used for the data from the world reference triad gives a relative standard deviation mean equal to σ = 0.3 % (σ157 = 0.33 %, σ183 = 0.34 % and σ185 = 0.23 %). However, the procedure of the Arosa triad gives monthly values of σ = 0.5 %. In this work, two ozone data sets are analysed: the first includes all the ozone measurements available, while the second only includes the simultaneous measurements of all three instruments. Furthermore, this paper also describes the Langley method used to determine the extraterrestrial constant (ETC) for the RBCC-E triad, the necessary first step toward accurate ozone calculation. Finally, the short-term or intraday consistency is also studied to identify the effect of the solar zenith angle on the precision of the RBCC-E triad.

Radioisotope Dilution Technique for Determination of Vitamin B12 in Foods

1982 ◽  
Vol 65 (1) ◽  
pp. 85-88 ◽  
Author(s):  
Patrick J Casey ◽  
Keevin R Speckman ◽  
Frank J Ebert ◽  
William E Hobbs
Keyword(s):  
Standard Deviation ◽  
Vitamin B12 ◽  
Relative Standard Deviation ◽  
Extraction Procedure ◽  
Dilution Technique ◽  
Microbiological Method ◽  
Relative Standard ◽  
Wide Range ◽  
The Mean

Abstract A radioisotope dilution (RID) method for the determination of vitamin B12 is presented. The method combines a standard extraction procedure (AOAC 43.108,12th ed.) with a commercially available RID assay kit. The method was evaluated on a wide range of fortified and unfortified food products. Recovery studies on both groups yielded average recoveries of 98.1 and 95.8%, respectively. Reproducibility data generated from replicate analyses on both groups gave a relative standard deviation of 6.9% for the fortified group and 9.2% for the unfortified group. For the samples studied, the mean vitamin B12 content determined by the RID method was 8.01 μg/100 g vs imean of 7.54 μg/100 g by the AOAC microbiological method; the correlation coefficient was r = 0.983.

Comparison of Automatic and Manual Turbidimetric Analyses of Tylosin in Feeds with the Plate Method

1973 ◽  
Vol 56 (2) ◽  
pp. 363-366
Author(s):  
Hussein S Ragheb ◽  
H Latham Breunig ◽  
Robert E Scroggs
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Plate Method ◽  
Relative Standard ◽  
Significant Difference ◽  
Aoac Method ◽  
Turbidimetric Assay ◽  
The Mean ◽  
The Difference ◽  
Feed Samples

Abstract Two laboratories participated in a comparison of a manual turbidimetric assay with the AUTOTURB® System and the AOAC method of analysis of tylosin in 4 feed samples. Results showed no significant difference between the 2 turbidimetric assays. When the AOAC method was considered, the difference between laboratories was significant. On an overall basis the turbidimetric methods were significantly higher than the plate method. The relative standard deviation was higher (6.72%) for the plate assay versus turbidimetric assay (4.5%). The mean recovery in both laboratories was significantly less than the labeled amount of tylosin by all 3 methods.

scholarly journals Performance Qualification of Two Processor-controlled Dosing Pumps for the Production of Mixed Infusion Solutions in a Closed System

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Terry Hennache ◽  
Gwénaëlle Clabaut ◽  
Lina Mustapha ◽  
Jean-Marc Dubaele ◽  
Frédéric Marçon
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Closed System ◽  
Potassium Concentration ◽  
Sodium Concentration ◽  
Relative Bias ◽  
Relative Standard ◽  
Performance Qualification ◽  
The Mean

Abstract: The aim of this study is to carry out performance qualifications of 2 processor-controlled dosing pumps for the production of mixed infusion solutions in a closed system.: Two dosing pumps have been qualified regarding their use: a processor-controlled dosing pump MediMix: The mean relative biases found with different products used for the qualifications of the two controllers were below the manufacturer’s specifications. When pumping operations were performed outside the manufacturer’s recommended ranges of volumes, relative bias remained below 10 %. Low relative bias (<3 %) and relative standard deviation (<1 %) were also found with routine controls (weight, osmolality, sodium concentration, potassium concentration) performed on test batches produced with the 12-pumps automated compounding device (ACD).: The single pump controller MediMix

In Vivo Rat Assay for True Protein Digestibility: Collaborative Study

1990 ◽  
Vol 73 (5) ◽  
pp. 801-805 ◽  
Author(s):  
Frank E Mcdonough ◽  
Fred H Steinke ◽  
Ghulam Sarwar ◽  
Bjorn O Eggum ◽  
Ricardo Bressani ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Collaborative Study ◽  
Protein Digestibility ◽  
Relative Standard ◽  
The Mean ◽  
Standard Deviations ◽  
Pinto Beans ◽  
True Protein ◽  
True Protein Digestibility

Abstract Eight laboratories participated In a collaborative study to estimate precision of a standardized rat assay for determining true protein digestibility In selected animal, fish, and cereal products. Each of 7 test protein sources (casein, tuna fish, macaroni/cheese, pea protein concentrate, rolled oats, pinto beans, and nonfat dried milk) was fed as the sole source of protein at a 10% protein level in mixed diets. Each diet was fed to 2 replicate groups of 4 rats each for a 4-day acclimation period and a 5-day balance period. Mean digestibilities ranged from 98.6% for casein to 72.6% for pinto beans. Repeatability standard deviations ranged from 0.5 to 2.0%; the mean relative standard deviation for repeatability was 0.9% (range 0.5-2.8%). Reproducibility standard deviations ranged from 1.2 to 3.2%, and the mean relative standard deviation for reproducibility was 2.4% (range 1.3- 4.4%). The method has been approved interim official first action for determining true protein digestibility In foods and ingredients

scholarly journals Development and Validation of an ICP-MS Method for Simultaneous Determination of Selected Metals in Electronic Cigarette Aerosol

2018 ◽  
Vol 28 (1) ◽  
pp. 2-13
Author(s):  
Shintaro Ohashi
Keyword(s):  
Standard Deviation ◽  
Nitric Acid ◽  
Simultaneous Determination ◽  
Propylene Glycol ◽  
Relative Standard Deviation ◽  
Icp Ms ◽  
Relative Standard ◽  
The Mean ◽  
The Impact

SummarySafety and quality standards for electronic cigarettes (e-cigarettes) have been introduced regionally. In 2016, the U.S. Food and Drug Administration (FDA) issued a rule to regulate e-cigarettes, requiring to report harmful and potentially harmful constituents (HPHCs). In the United Kingdom, the British Standards Institution (BSI) specified the metals to be monitored for e-cigarettes. In this study, a method was developed and validated for the simultaneous determination of 13 metals (Be, Al, Cr, Fe, Co, Ni, Cu, As, Se, Ag, Cd, Sn and Pb) in e-cigarette aerosol. Furthermore, matrix effects of major constituents in the aerosol were investigated using glycerol or 1,2-propylene glycol solutions. E-cigarette aerosol was generated by a rotary smoking machine according to CORESTA Recommended Method N° 81 and collected by an electrostatic precipitator coupled to an impinger containing nitric acid. The collected aerosol was dissolved in nitric acid and an aliquot of this solution was analyzed by inductively coupled plasma mass spectrometry (ICP-MS) equipped with a collision/reaction cell.The linearity of the calibration curve was observed in the range of 0.2 to 100 ng/mL for each analyte; the correlation coefficients were 0.998 or larger, the mean recovery of each standard level ranged from 92.6 to 104.5% and the relative standard deviation amounted to max. 9.5%. Accuracy, repeatability and specificity were validated by spiking three different amounts of analytes into e-cigarette aerosol; the mean recovery of each spiking level ranged from 88.7 to 110.3% with a relative standard deviation amounting to max. 9.2% for all analytes. Background contamination from aerosol generation and collection system existed for some analytes, especially for Al, Fe, Cu and Sn. The potential sources of contamination should be identified and controlled to reduce the impact of contamination on quantification. In addition, the actual values for samples should be reported with method blank statistics. Increase of the concentrations of glycerol and 1,2-propylene glycol in the prepared sample led to the overestimation of As and Se. The amount of polyols in the collected aerosol should be monitored and controlled for the accurate quantification of As and Se.

scholarly journals Determination of Glyphosate and Aminomethylphosphonic Acid in Crops by Capillary Gas Chromatography with Mass-Selective Detection: Collaborative Study

2001 ◽  
Vol 84 (3) ◽  
pp. 823-846 ◽  
Author(s):  
Philip L Alferness ◽  
Lawrence A Wiebe ◽  
L Anderson ◽  
O Bennett ◽  
M Bosch ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Capillary Gas Chromatography ◽  
Collaborative Study ◽  
Selective Detection ◽  
Aminomethylphosphonic Acid ◽  
Relative Standard ◽  
The Mean

Abstract A collaborative study was conducted to validate a method for the determination of glyphosate and aminomethylphosphonic acid (AMPA) in crops. The analytes are extracted from crops with water, and the crude extracts are then subjected to a cation exchange cleanup. The analytes are derivatized by the direct addition of the aqueous extract into a mixture of heptafluorobutanol and trifluoroacetic anhydride. The derivatized analytes are quantitated by capillary gas chromatography with mass-selective detection (MSD). The collaborative study involved 13 laboratories located in 5 countries 12 laboratories returned valid data sets. The crops tested were field corn grain, soya forage, and walnut nutmeat at concentrations of 0.050, 0.40, and 2.0 mg/kg. The study used a split-level pair replication scheme with blindly coded laboratory samples. Twelve materials were analyzed, including 1 control and 3 split-level pairs for each matrix, 1 pair at each nominal concentration. For glyphosate, the mean recovery was 91%, the average intralaboratory variance, the repeatability relative standard deviation (RSDr), was 11%, and the interlaboratory variance, the reproducibility relative standard deviation (RSDR), was 16%. For AMPA, the mean recovery was 87%, the RSDr was 16%, and the RSDR was 25% at mg/kg levels.

scholarly journals A Simple Method for Evaluating Data from an Interlaboratory Study

1998 ◽  
Vol 81 (6) ◽  
pp. 1257-1266 ◽  
Author(s):  
William Horwitz ◽  
Paul Britton ◽  
Stuart J Chirtel
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Environmental Protection Agency ◽  
Large Scale ◽  
Extreme Values ◽  
Absorption Spectrometry ◽  
Performance Study ◽  
Method Performance ◽  
Simple Method ◽  
Relative Standard

Abstract Large-scale laboratory- and method-performance studies involving more than about 30 laboratories may be evaluated by calculating the HORRAT ratio for each test sample (HORRAT = [experimentally found among-laboratories relative standard deviation] divided by [relative standard deviation calculated from the Horwitz formula]). The chemical analytical method is deemed acceptable per se if HORRAT ͌ 1.0 (± 0.5). If HORRAT is ≳2.0, the most extreme values are removed successively until an "acceptable" ratio is obtained. The laboratories responsible for the extreme values that are removed should examine their technique and procedures. If ≳15% of the values have to be removed, the instructions and the methods should be examined. This suggested computation procedure is simple and does not require statistical outlier tables. Proposed action limits may be adjusted according to experience. Data supporting U.S. Environmental Protection Agency method 245.1 for mercury in waters (manual cold-vapor atomic absorption spectrometry), supplemented by subsequent laboratory-performance data, were reexamined in this manner. Method-performance parameters (means and among-laboratories relative standard deviations) were comparable with results from the original statistical analysis that used a robust biweight procedure for outlier removal. The precision of the current controlled performance is better by a factor of 4 than that of estimates resulting from the original method-performance study, at the expense of rejecting more experimental values as outliers.

An Automated Procedure for the Determination of Ammonia in Tobacco

1972 ◽  
Vol 6 (4) ◽  
Author(s):  
P.F. Collins ◽  
W.W. Lawrence ◽  
J.F. Williams
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Distillation Method ◽  
Relative Standard ◽  
Tobacco Sample ◽  
Automated Determination

AbstractA procedure for the automated determination of ammonia in tobacco has been developed. Ammonia is extracted from the ground tobacco sample with water and is determined with a Technicon Auto Analyser system which employs separation of the ammonia through volatilization followed by colourimetry using the phenate-hypochlorite reaction. The procedure has been applied to a variety of tobaccos containing from 0.02 to 0.5 % ammonia with an overall relative standard deviation of 2 %. The accuracy of the procedure as judged by recovery tests and by comparison to a manual distillation method is considered adequate

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