Precision measurement of the 5 2S1/2 - 4 2D5/2 quadrupole transition isotope shift between 88Sr+ and 86Sr+

We have measured the isotope shift of the narrow quadrupole-allowed 5 2S1/2 - 4 2D5/2 transition in 86Sr+ relative to the most abundant isotope 88Sr+. This was accomplished using high-resolution laser spectroscopy of individual trapped ions, and the measured shift is Delta-nu_meas^(88,86) = 570.281(4) MHz. We have also tested a recently developed and successful method for ab-initio calculation of isotope shifts in alkali-like atomic systems against this measurement, and our initial result of Delta-nu_calc^(88,86) = 457(28) MHz is also presented. To our knowledge, this is the first high precision measurement and calculation of that isotope shift. While the measurement and the calculation are in broad agreement, there is a clear discrepancy between them, and we believe that the specific mass shift was underestimated in our calculation. Our measurement provides a stringent test for further refinements of theoretical isotope shift calculation methods for atomic systems with a single valence electron

Annotated Bibliography Of Generative Grammar

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98281/1/j.1467-1770.1962.tb01267.x.pd

Modeling-based determination of physiological parameters of systemic VOCs by breath gas analysis, part 2

In a recent paper we presented a simple two compartment model which describes the influence of inhaled concentrations on exhaled breath concentrations for volatile organic compounds (VOCs) with small Henry constants. In this paper we extend this investigation concerning the influence of inhaled concentrations on exhaled breath concentrations for VOCs with higher Henry constants. To this end we extend our model with an additional compartment which takes into account the influence of the upper airways on exhaled breath VOC concentrations

Modeling-based determination of physiological parameters of systemic VOCs by breath gas analysis: a pilot study

In this paper we develop a simple two compartment model which extends the Farhi equation to the case when the inhaled concentration of a volatile organic compound (VOC) is not zero. The model connects the exhaled breath concentration of systemic VOCs with physiological parameters such as endogenous production rates and metabolic rates. Its validity is tested with data obtained for isoprene and inhaled deuterated isoprene-D5.Comment: 16 page

A modeling-based evaluation of isothermal rebreathing for breath gas analyses of highly soluble volatile organic compounds

Isothermal rebreathing has been proposed as an experimental technique for estimating the alveolar levels of hydrophilic volatile organic compounds (VOCs) in exhaled breath. Using the prototypic test compound acetone we demonstrate that the end-tidal breath profiles of such substances during isothermal rebreathing show characteristics that contradict the conventional pulmonary inert gas elimination theory due to Farhi. On the other hand, these profiles can reliably be captured by virtue of a previously developed mathematical model for the general exhalation kinetics of highly soluble, blood-borne VOCs, which explicitly takes into account airway gas exchange as major determinant of the observable breath output. This model allows for a mechanistic analysis of various rebreathing protocols suggested in the literature. In particular, it clarifies the discrepancies between in vitro and in vivo blood-breath ratios of hydrophilic VOCs and yields further quantitative insights into the physiological components of isothermal rebreathing.Comment: 21 page

How should Program Evaluation Standards inform the use of cost-benefit analysis in evaluation?

Background: Cost-benefit analysis (CBA), like any other evaluation method, should be used in ways that uphold program evaluation standards and should be subjected to metaevaluation. In contrast to the broad remit of program evaluation standards, guidelines for economic evaluation focus mainly on technical aspects of evaluation quality, aimed at ensuring precision, accuracy, and reliability. Can CBA be conducted in adherence both to program evaluation standards and to its own methodological principles, or are there areas where expectations conflict? Purpose: Assess the potential for CBA to be conducted in keeping with the Program Evaluation Standards (PES) of the Joint Committee on Standards for Educational Evaluation. Setting: Analysis applies to any setting in which CBA is being considered as an evaluation method. Intervention: N/A Research Design:  Methodological principles underpinning CBA were systematically assessed against the PES, to determine the extent to which CBA can be conducted in a manner aligned with these standards. CBA was rated according to whether it can follow each standard in principle, not the extent to which economists follow a given standard in practice. Data Collection and Analysis: This assessment was undertaken from a theoretical perspective, through analysis of relevant literature. The ratings are evaluative; they represent the judgments of the author, made on the basis of explicit definitions. Findings: Some ethical principles espoused in the PES are also required in CBA. On the other hand, some of the PES are not explicit requirements in CBA, though they could be applied by evaluators or economists when conducting a CBA. However, some PES logically cannot be met by CBA if it is used as a stand-alone method. All PES can theoretically be met when an evaluation combines CBA with other methods. In order to use CBA in adherence to PES, evaluators and economists must take an explicit interest in the effects of their analysis on people’s lives. This has significant implications for the way CBA should be used, including the nature and extent of stakeholder involvement, the potential use of CBA in conjunction with other methods, and decisions about when not to use CBA. As with any evaluation method, deliberation is necessary over whether, when, and how to use CBA. Keywords: cost-benefit analysis, program evaluation standards, metaevaluatio

Physiological modeling of isoprene dynamics in exhaled breath

Human breath contains a myriad of endogenous volatile organic compounds (VOCs) which are reflective of ongoing metabolic or physiological processes. While research into the diagnostic potential and general medical relevance of these trace gases is conducted on a considerable scale, little focus has been given so far to a sound analysis of the quantitative relationships between breath levels and the underlying systemic concentrations. This paper is devoted to a thorough modeling study of the end-tidal breath dynamics associated with isoprene, which serves as a paradigmatic example for the class of low-soluble, blood-borne VOCs. Real-time measurements of exhaled breath under an ergometer challenge reveal characteristic changes of isoprene output in response to variations in ventilation and perfusion. Here, a valid compartmental description of these profiles is developed. By comparison with experimental data it is inferred that the major part of breath isoprene variability during exercise conditions can be attributed to an increased fractional perfusion of potential storage and production sites, leading to higher levels of mixed venous blood concentrations at the onset of physical activity. In this context, various lines of supportive evidence for an extrahepatic tissue source of isoprene are presented. Our model is a first step towards new guidelines for the breath gas analysis of isoprene and is expected to aid further investigations regarding the exhalation, storage, transport and biotransformation processes associated with this important compound.Comment: 14 page