125,076 research outputs found
Compte rendu de Robert L. Jaffe & Washington Taylor : «The Physics of Energy»
No full textJaffe (Robert L.) - Taylor (Washington), The Physics of Energy. – Cambridge : Cambridge University Press, 2018. – 874 p. – 1 vol. broché de 22,5 × 28 cm. – £ 59,99. – isbn 978-1-107-01665-1
Market Value and Patent Citations: A First Look
No full textAs patent data become more available in machine-readable form, an increasing number of researchers have begun to use measures based on patents and their citations as indicators of technological output and information flow. This paper explores the economic meaning of these citation-based patent measures using the financial market valuation of the firms that own the patents. Using a new and comprehensive dataset containing over 4800 U. S. Manufacturing firms and their patenting activity for the past 30 years, we explore the contributions of R&D spending, patents, and citation-weighted patents to measures of Tobin's Q for the firms. We find that citation-weighted patent stocks are more highly correlated with market value than patent stocks themselves and that this fact is due mainly to the high valuation placed on firms that hold very highly cited patents.
Results of the recalibration of creatinine measurement with the modular Beckman Coulter® Jaffe creatinine method
No full textAbstractSerum creatinine is important for detecting the beginning of a decline in kidney function. The Beckman Coulter Jaffe reagents for measuring creatinine have been standardized to the internationally accepted reference method: isotope dilution mass spectrometry (IDMS). The impact of this recalibration on the Beckman CoulterRecalibrated Jaffe (calibrator set points IDMS traceable) and classic National Institute of Standards and Technology (NIST) creatinine methods (traceable to NIST 914a) were compared with an enzymatic method (Sentinel, traceable to NIST SRM 967). All measurements were performed on Synchron DxC 800 systems. Imprecision of the routine methods was studied using the Clinical and Laboratory Standards Institute (CLSI) protocols and laboratory quality survey. Thirteen plasma pools, with concentrations <354 μmol/L, were analyzed with a gas chromatography isotope dilution mass spectrometry (GC-IDMS) method and routine methods. Total error of 8.2% based on biological variability, set on the GC-IDMS values and acceptance criteria (bias <5%, imprecision <8% at concentrations ≥88.4 μmol/L and a maximum 10% increase in the relative error of estimated glomerular filtration rate (eGFR) of the National Kidney Disease Educational Program (NKDEP) were used for evaluating analytical performance of the routine methods studied.After recalibration of the Jaffe method, median bias (μmol/L) decreased from 12.4 (95% CI: 9.1–21.2) to 7.3 (95% CI: 1.5–10.5). Imprecision of the Jaffe method is in agreement with the claim of the manufacturer, namely <9 μmol/L or <3% below or above 292 μmol/L. Below creatinine of 88.4 μmol/L, imprecision of the recalibrated Jaffe and enzymatic methods is between 4.1% and 6.9%, and 5.0% and 7.1%, respectively, and significantly different (p=0.02 for both the Jaffe and enzymatic methods) from the goal, based on biological variability, of 2.7%. For the adult pools, all recalibrated Jaffe and enzymatic results fall within the total error of 8.2%. In the pediatric samples, one-third of the recalibrated Jaffe and three of the six enzymatic results fall within this total error goal.Recalibration significantly reduced bias of the Jaffe method. For pediatric samples, recalibrated Jaffe results do not comply with either the imprecision goal or the total error based on biological variability. Adult recalibrated Jaffe results are in compliance with the goals based on biological variability and with the acceptance criteria from the NKDEP.</jats:p
Specificity Characteristics of 7 Commercial Creatinine Measurement Procedures by Enzymatic and Jaffe Method Principles
No full textAbstract
BACKGROUND
Standardized calibration does not change a creatinine measurement procedure's susceptibility to potentially interfering substances.
METHODS
We obtained individual residual serum or plasma samples (n = 365) from patients with 19 different disease categories associated with potentially interfering substances and from healthy controls. Additional sera at 0.9 mg/dL (80 μmol/L) and 3.8 mg/dL (336 μmol/L) creatinine were supplemented with acetoacetate, acetone, ascorbate, and pyruvate. We measured samples by 4 enzymatic and 3 Jaffe commercially available procedures and by a liquid chromatography/isotope dilution/mass spectrometry measurement procedure against which biases were determined.
RESULTS
The number of instances when 3 or more results in a disease category had biases greater than the limits of acceptability was 28 of 57 (49%) for Jaffe and 14 of 76 (18%) for enzymatic procedures. For the aggregate group of 59 diabetes samples with increased β-hydroxybutyrate, glucose, or glycosylated hemoglobin (Hb A1c), the enzymatic procedures had 10 biased results of 236 (4.2%) compared with 89 of 177 (50.3%) for the Jaffe procedures, and these interferences were highly procedure dependent. For supplemented sera, interferences were observed in 11 of 24 (46%) of groups for Jaffe and 8 of 32 (25%) of groups for enzymatic procedures and were different at low or high creatinine concentrations.
CONCLUSIONS
There were differences in both magnitude and direction of bias among measurement procedures, whether enzymatic or Jaffe. The influence of interfering substances was less frequent with the enzymatic procedures, but no procedure was unaffected. The details of implementation of a method principle influenced its susceptibility to potential interfering substances.
</jats:sec
A Risk Assessment of the Jaffe vs Enzymatic Method for Creatinine Measurement in an Outpatient Population.
No full textBackgroundThe Jaffe and enzymatic methods are the two most common methods for measuring serum creatinine. The Jaffe method is less expensive than the enzymatic method but is also more susceptible to interferences. Interferences can lead to misdiagnosis but interferences may vary by patient population. The overall risk associated with the Jaffe method depends on the probability of misclassification and the consequences of misclassification. This study assessed the risk associated with the Jaffe method in an outpatient population. We analyzed the discordance rate in the estimated glomerular filtration rate based on serum creatinine measurements obtained by the Jaffe and enzymatic method.MethodsMethod comparison and risk analysis. Five hundred twenty-nine eGFRs obtained by the Jaffe and enzymatic method were compared at four clinical decision limits. We determined the probability of discordance and the consequence of misclassification at each decision limit to evaluate the overall risk.ResultsWe obtained 529 paired observations. Of these, 29 (5.5%) were discordant with respect to one of the decision limits (i.e. 15, 30, 45 or 60 ml/min/1.73m2). The magnitude of the differences (Jaffe result minus enzymatic result) were significant relative to analytical variation in 21 of the 29 (72%) of the discordant results. The magnitude of the differences were not significant relative to biological variation. The risk associated with misclassification was greatest at the 60 ml/min/1.73m2 decision limit because the probability of misclassification and the potential for adverse outcomes were greatest at that decision limit.ConclusionThe Jaffe method is subject to bias due to interfering substances (loss of analytical specificity). The risk of misclassification is greatest at the 60 ml/min/1.73m2 decision limit; however, the risk of misclassification due to bias is much less than the risk of misclassification due to biological variation. The Jaffe method may pose low risk in selected populations if eGFR results near the 60 ml/min/1.73m2 decision limit are interpreted with caution
Use and Prognostic Implications of Cardiac Troponin in COVID-19
No full textMyocardial injury is common in patients with COVID-19 and is associated with an adverse prognosis. Cardiac troponin (cTn) is used to detect myocardial injury and assist with risk stratification in this population. SARS-CoV-2 infection can play a role in the pathogenesis of acute myocardial injury due to both direct and indirect damage to the cardiovascular system. Despite the initial concerns about an increased incidence of acute myocardial infarction (MI), most cTn increases are related to chronic myocardial injury due to comorbidities and/or acute nonischemic myocardial injury. This review will discuss the latest findings on this topic
Patterns of gene content and co-occurrence constrain the evolutionary path toward animal association in CPR bacteria
No full textSubset of Candidate Phyla Radiation (CPR) genomes associated with Jaffe et al. 2021 ("Patterns of gene content and co-occurrence constrain the evolutionary path toward animal association in CPR bacteria") in FASTA format and supplementary materials/files
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
- …
