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Measurement Protocol (measurement + protocol)

Distribution by Scientific Domains

Medical Sciences	44%

Selected Abstracts

Design and Costs of a Measurement Protocol for Trades in Soil Carbon Credits

CANADIAN JOURNAL OF AGRICULTURAL ECONOMICS, Issue 3 2004
Siân Mooney
Previous work has demonstrated that in the absence of transaction costs, contracts that pay producers per carbon (C) credit are more efficient than those that tie payments to changes in management practices. In this paper we develop a measurement protocol to support contracts for C credits and estimate its implementation costs using an empirical example. We find that the costs of implementing a measurement protocol for soil C credits depend on: the price of credits; the regional heterogeneity in C values as well as assumed error and confidence intervals. We find that the upper estimate of measurement costs associated with a contract that pays producers per C credit can be as little as 3% of the value of a credit. These contract measurement costs are less than the efficiency gains from implementing a per-credit contract. Des travaux antérieurs montrent que si la transaction ne coûte rien, les ententes prévoyant la rémuné ration des agriculteurs par cré dit carbone (C) sont plus efficaces que celles oè les paiements sont lié s à l'adaptation des pratiques culturales. Dans leur article, les auteurs proposent une mé thode de calculpour de telles ententes et estiment ce que coûterait son implantation au moyen d'un exemple empirique. On constate que, pour les cré dits C du sol, le coût de mise en æuvre dépend du prix des cré dits, de l'hé térogénéité régionale de la valeur des crédits ainsi que dxe l'erreur présumée et des intervalles de confiance. On se rend compte que la plus haute estimation du coût des ententes rémunérant les agriculteurs enfonction des crédits C ne dépasse pas trois pour cent de la valeur du crédit. De tels coûts sont inférieurs aux gains de productivité résultant de l'adoption d'une entente articulée sur les crédits C. [source]

Isotopic metrology of carbon dioxide.

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 8 2003

We report a pilot study of high-precision differential isotope ratio measurements made on replicate samples of pure carbon dioxide using three instruments of identical manufacture. Measurement protocols were designed to explore the effects of sample size, ion source conductance, and inlet changeover equilibration time on the raw measurements. Our goal was better understanding of factors that influence these measurements in order to establish procedures for highly reproducible and accurate determinations of Reference Material (RM) isotopic compositions. Evaluation and modeling of reported data illuminated effects consistent with two instrumental memory sources,one short-lived (t½,,,10 s) and the other long-lived (t½,,,6,10,min), uncompensated by normal background measurements,that can significantly influence measurements made by the dual inlet method. These biases, proportional to the difference in isotopic compositions between the measured sample and reference gases, decrease in magnitude with increasing sample size, source conductance, and equilibration time. We observed biases as high as 0.1, per 10, difference between sample and reference gases. These memory sources may be responsible for measured ,13C values of RMs generally being highly reproducible within any single laboratory but less reproducible among independent laboratories. The magnitude of the bias is consistent with the ranges of ,13C values reported in prior laboratory intercomparisons. Uncertainties are most likely due to high and variable long-lived memory among the instruments tested. Published in 2003 by John Wiley & Sons, Ltd. [source]

Isotopic metrology of carbon dioxide.

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 8 2003

We report high-precision isotopic carbon dioxide measurements, made before and after ion source modification to gas isotope ratio mass spectrometry (IRMS) instruments. Measurement protocols were designed to explore the effects of ion source material substitution, source conductance, inlet pressure, electron emission, acceleration potential, and inlet changeover equilibration time. After modification of the IRMS instruments at the National Institute of Standards and Technology (NIST) and the Max-Planck-Institute for Chemistry (MPI-Mainz), immediate changes were observed. At NIST, measurements were no longer sensitive to inlet equilibration times greater than 15,s, and different settings of ion source conductance resulted in ,13C shifts of about 0.04, per 10, measurement difference between sample and reference, a five-fold improvement. No significant changes in machine performance were observed after a month of use. After a year, performance had degraded slightly, but was controlled by ion source cleaning and the use of low-energy ion acceleration to minimize sputtering. At MPI-Mainz, results were very similar. We report cross-contamination coefficients measured since 1996, and discuss the role of adsorption, ion implantation, and sputtering on cross contamination in mass spectrometry systems. We recommend that users of high-precision IRMS instruments test for and minimize the effects described. Published in 2003 by John Wiley & Sons, Ltd. [source]

Gated dynamic 31P MRS shows reduced contractile phosphocreatine breakdown in mice deficient in cytosolic creatine kinase and adenylate kinase

NMR IN BIOMEDICINE, Issue 5 2009
Hermien E. Kan
Abstract We developed a new dedicated measurement protocol for dynamic 31P MRS analysis in contracting calf muscles of the mouse, using minimally invasive assessment of the contractile force combined with the acquisition of spectroscopic data gated to muscle contraction and determination of phosphocreatine (PCr) recovery rate and ATP contractile cost. This protocol was applied in a comparative study of six wild type (WT) mice and six mice deficient in cytosolic creatine kinase and adenylate kinase isoform 1 (MAK,/, mice) using 70 repeated tetanic contractions at two contractions per minute. Force levels during single contractions, and metabolite levels and tissue pH during resting conditions were similar in muscles of MAK,/, and WT mice. Strikingly, muscle relaxation after contraction was significantly delayed in MAK,/, mice, but during repeated contractions, the decrease in the force was similar in both mouse types. Gated data acquisition showed a negligible PCr breakdown in MAK,/, immediately after contraction, without a concomitant decrease in ATP or tissue pH. This protocol enabled the determination of rapid PCr changes that would otherwise go unnoticed due to intrinsic low signal-to-noise ratio (SNR) in mouse skeletal muscles combined with an assessment of the PCr recovery rate. Our results suggest that MAK,/, mice use alternative energy sources to maintain force during repeated contractions when PCr breakdown is reduced. Furthermore, the absence of large increases in adenosine diphosphate (ADP) or differences in force compared to WT mice in our low-intensity protocol indicate that creatine kinase (CK) and adenylate kinase (AK) are especially important in facilitating energy metabolism during very high energy demands. Copyright © 2009 John Wiley & Sons, Ltd. [source]

The effect of measurement protocol on active cervical motion in healthy subjects

PHYSIOTHERAPY RESEARCH INTERNATIONAL, Issue 3 2002
Professor Zeevi Dvir
Abstract Background and Purpose Although the assessment of cervical motion is routinely performed in clinical practice, no standard protocol for this procedure has ever been established formally. The specific aim of the present study was to select from four different measurement protocols the one which was most stable in terms of reproducibility and was appropriate for clinical and/or medicolegal applications. Method A repeated measurement, test,retest of cervical motion study design using an ultrasound-based system for three-dimensional (3D) motion analysis; cervical range of motion was measured along the six primary directions: flexion; extension; right and left rotation; and right and left lateral flexion, in 20 healthy subjects who were tested twice over a period of lasting from one to four weeks. ,Protocol A' (reciprocal,intermittent testing) consisted of moving the head along a given primary direction, return to the neutral position, a pause and then motion to the opposite primary direction and return to neutral position. These movements were repeated three times. ,Protocol B' (reciprocal,continuous testing) was identical to Protocol A, but without the pause between the primary directions. ,Protocol C' consisted of three repetitions of the same primary direction with a break between two consecutive primary directions. Three sets of six randomly ordered primary directions constituted ,Protocol D'. Results Protocol D was associated with a significantly smaller range of motion and with the least intra-test reproducibility, as indicated by the coefficient of variation. The differences between the other protocols were largely negligible. Conclusion In routine clinical practice, either of protocols A, B or C may be applied. Copyright © 2002 Whurr Publishers Ltd. [source]

Design and Costs of a Measurement Protocol for Trades in Soil Carbon Credits

Reproducibility evaluation of gross and net walking efficiency in children with cerebral palsy

DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 1 2007
Merel-Anne Brehm MSc
In evaluating energy cost (EC) of walking, referred to as walking efficiency, the use of net measurement protocols (i.e. net=gross-resting) has recently been recommended. However, nothing is known about the comparative reproducibility of net protocols and the commonly used gross protocols. Ten minutes of resting and 5 minutes of walking at a self-selected speed were used to determine gross and net EC in 13 children with spastic cerebral palsy (CP; seven males, six females; mean age 8y 7mo [SD 3y 4mo], range 4y 1mo,13y) and in 10 children (three males, seven females) with typical development. In the former, their Gross Motor Function Classification System levels ranged from Level I to Level III; and seven had hemiplegia and six diplegia. There were four repeated sessions on different days, with periods of 1 week between sessions. Reproducibility was assessed for speed, and gross and net EC, by using the standard error of measurement. The results of this preliminary study showed that EC measurements were more variable for children with CP than for children with typical development. Furthermore, in both groups there was considerably more variability in the net measurements than in the gross measurements. We conclude that, on the basis of the methodology used, the use of gross EC, rather than net EC, seems a more sensitive measure of walking efficiency to detect clinically relevant changes in an individual child with CP. [source]

The effect of measurement protocol on active cervical motion in healthy subjects

THE HISTORY OF THE LAWRENCE BERKELEY NATIONAL LABORATORY INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS PROGRAMME FOR ARCHAEOLOGICAL AND GEOLOGICAL MATERIALS

ARCHAEOMETRY, Issue 2 2007
F. ASARO
The Lawrence Berkeley National Laboratory pottery provenance group developed standards and instrumental neutron activation analysis (INAA) methods that are used at many archaeometry laboratories around the world. The background and development of ,Standard Pottery' and of methods for INAA are described. Early pottery provenance studies are described, and other research programmes, involving obsidian and magmatic mixing, the origin of the stone used for the Colossi of Memnon, and the ,Plate of Brass', are mentioned. Research work by the Laboratory included the discovery of the world-wide iridium anomaly and extensive subsequent research on what has come to be known as the ,Asteroid Impact Theory'. Characteristics of the analytical programme for pottery provenance work, including overall aims, precision and accuracy, intercalibration, and irradiation and measurement protocols, are discussed. New research areas developed in the past 15 years, to broaden the usefulness of chemical compositional data for archaeological investigation, and examples of recent work, are described. This research, which makes use of high-precision X-ray fluorescence analysis in addition to INAA measurements on sample splits, includes distinguishing the products of different workshops located at the same production site, studies on the significance of the distribution of silver in archaeological pottery and the use of high-precision chemical compositional data as an aid for making chronological distinctions. [source]