2,219 research outputs found
Lines in the sand: Social representations of substance use boundaries in life narratives
This study identifies social representations in interviews about alcohol and substance use in the discourse of 129 young adults, who were interviewed for 2.5 to 3.5 hr each for their life histories and use or nonuse of alcoholic beverages and drugs. Respondents spontaneously delineated their substance use boundaries, creating a continuum of behaviors with boundary points separating acceptable from unacceptable behaviors. They used signaling expressions to indicate go and stop signs and movement along the substance use continuum and reported negotiating substance use boundaries both internally and with peers. A ubiquitous narrative element was the cautionary tale, in which a negative exemplar goes too far with alcohol and/or drugs, providing an example of the possible negative outcomes of transgressing boundaries. In general, the narratives revealed complex relationships to alcohol and other drugs that may be useful in refining messages for more effective communication in prevention and intervention programs
Technical note: A geostatistical fixed-lag Kalman smoother for atmospheric inversions
International audienceInverse modeling methods are now commonly used for estimating surface fluxes of carbon dioxide, using atmospheric mass fraction measurements combined with a numerical atmospheric transport model. The geostatistical approach to flux estimation takes advantage of the spatial and/or temporal correlation in fluxes and does not require prior flux estimates. In this work, a geostatistical implementation of a fixed-lag Kalman smoother is developed to improve the computational efficiency of the inverse problem. This method makes it feasible to perform multi-year inversions, at fine resolutions, and with large amounts of data. The new method is applied to the recovery of global gridscale carbon dioxide fluxes for 1997 to 2001 using pseudodata representative of a subset of the NOAA-ESRL Cooperative Air Sampling Network
High resolution measurements of kinetic energy release distributions of neon, argon, and krypton cluster ions using a three sector field mass spectrometer
Using a newly constructed three sector field mass spectrometer (resulting in a BE1E2 field configuration) we have measured the kinetic energy release distributions of neon, argon, and krypton cluster ions. In the present study we used the first two sectors, B and E1, constituting a high resolution mass spectrometer, to select the parent ions in terms of mass, charge, and energy, and studied the decay of those ions in the third field free region. Due to the improved mass resolution we were able to extend earlier studies carried out with a two sector field machine, where an upper size limit arose from the fact that several isotopomers contribute to a decaying parent ion beam when the cluster size exceeds a certain value. Furthermore we developed a new data analysis. It allows us to model also fragment ion peaks that are a superposition of different decay reactions and thus we can determine the average kinetic energy release for all decay reactions of a given cluster ion. In a further step we used these results to determine the binding energies of cluster ions Rg(n) (ngreater than or equal to10) by applying finite heat bath theory. The smaller sizes have not been included in this analysis, because the validity of finite heat bath theory becomes questionable below napproximate to10. The present average kinetic energy releases and binding energies are compared with other experiments and various calculations. (C) 2004 American Institute of Physics
General method for extracting the quantum efficiency of dispersive qubit readout in circuit QED
We present and demonstrate a general three-step method for extracting the
quantum efficiency of dispersive qubit readout in circuit QED. We use active
depletion of post-measurement photons and optimal integration weight functions
on two quadratures to maximize the signal-to-noise ratio of the
non-steady-state homodyne measurement. We derive analytically and demonstrate
experimentally that the method robustly extracts the quantum efficiency for
arbitrary readout conditions in the linear regime. We use the proven method to
optimally bias a Josephson traveling-wave parametric amplifier and to quantify
different noise contributions in the readout amplification chain.Comment: 10 pages, 6 figure
Amazon.com vs. EBSCO’s GOBI Library Solutions: Evaluating New and Used Book Vendors While Building a Diverse Collection
This article will share a small college’s comparison of the benefits and challenges that occurred when ordering a curated list of new and used print books from EBSCO’s GOBI Library Solutions, a traditional book jobber, instead of Amazon.com, a book retailer. The researchers analyzed the acquisition process, final purchase cost, and reconciliation workflow between the two vendors. Results from this study revealed a 3.1% final cost difference between the two vendors. Additionally, this case study addressed the workflow undertaken to build a curated list of new and used LGBTQ and Title IX print books. This research contributed to the literature as scholarship that compared titles in academic libraries between one subject area, gender studies, in combination with an assessment of the collection development, acquisition, and ordering software tools provided to academic libraries from a traditional book jobber and a book retailer was scant
Atmospheric inverse modeling with known physical bounds: an example from trace gas emissions
Many inverse problems in the atmospheric sciences involve parameters with
known physical constraints. Examples include nonnegativity (e.g., emissions
of some urban air pollutants) or upward limits implied by reaction or
solubility constants. However, probabilistic inverse modeling approaches
based on Gaussian assumptions cannot incorporate such bounds and thus often
produce unrealistic results. The atmospheric literature lacks consensus on
the best means to overcome this problem, and existing atmospheric studies
rely on a limited number of the possible methods with little examination of
the relative merits of each.
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This paper investigates the applicability of several approaches to
bounded inverse problems. A common method of data transformations is found to
unrealistically skew estimates for the examined example
application. The method of Lagrange multipliers and two Markov chain Monte Carlo (MCMC) methods
yield more realistic and accurate results. In general, the examined
MCMC approaches produce the most realistic result but can require
substantial computational time. Lagrange multipliers offer an
appealing option for large, computationally intensive problems
when exact uncertainty bounds are less central to the
analysis. A synthetic data inversion of US anthropogenic methane
emissions illustrates the strengths and weaknesses of each approach
Efficacy of a zinc lactate mouthwash and tongue scraping in the reduction of oral halitosis: A single-blind, controlled, crossover clinical trial—a pilot study
Halitosis is defined as an unpleasant odor that comes out of the mouth. The aim of this study was to investigate the effect of zinc lactate mouthwash and tongue scraping on oral halitosis. The study was conducted on 60 volunteers that were divided into two groups and followed two types of 14-day oral hygiene protocols on a cross-over basis after a 7-day wash-out period. One protocol was based on tooth brushing only, while the other was based on additional mouth rinsing with a zinc lactate product and tongue scraping. Morning mouth breath was assessed organoleptic and by volatile sulfur compound concentrations. The highest mean organoleptic and volatile sulfur compound measurement values were found in the tooth brushing without mouth washing and tongue scraping oral hygiene protocol (p < 0.05). The zinc lactate mouthwash combined with tongue scraping appears to be an important hygienic procedure to reduce breath odor. © 2021 by the authors. Licensee MDPI, Basel, Switzerland
Spatial and temporal resolution of carbon flux estimates for 1983?2002
International audienceWe discuss the spatial and temporal resolution of monthly carbon flux estimates for the period 1983?2002 using a fixed-lag Kalman Smoother technique with a global chemical transport model, and the GLOBALVIEW data product. The observational network has expanded substantially over this period, and we the improvement in the constraints provided flux estimates by observations for the 1990's in comparison to the 1980's. The estimated uncertainties also decrease as observational coverage expands. In this study, we use the Globalview data product for a network that changes every 5 y, rather than using a small number of continually-operating sites (fewer observational constraints) or a large number of sites, some of which may consist almost entirely of extrapolated data. We show that the discontinuities resulting from network changes reflect uncertainty due to a sparse and variable network. This uncertainty effectively limits the resolution of trends in carbon fluxes. The ability of the inversion to distinguish, or resolve, carbon fluxes at various spatial scales is examined using a diagnostic known as the resolution kernel. We find that the global partition between land and ocean fluxes is well-resolved even for the very sparse network of the 1980's, although prior information makes a significant contribution to the resolution. The ability to distinguish zonal average fluxes has improved significantly since the 1980's, especially for the tropics, where the zonal ocean and land biosphere fluxes can be distinguished. Care must be taken when interpreting zonal average fluxes, however, since the lack of air samples for some regions in a zone may result in a large influence from prior flux estimates for these regions. We show that many of the TransCom 3 source regions are distinguishable throughout the period over which estimates are produced. Examples are Boreal and Temperate North America. The resolution of fluxes from Europe and Australia has greatly improved since the 1990's. Other regions, notably Tropical South America and the Equatorial Atlantic remain practically unresolved. Comparisons of the average seasonal cycle of the estimated carbon fluxes with the seasonal cycle of the prior flux estimates reveals a large adjustment of the summertime uptake of carbon for Boreal Eurasia, and an earlier onset of springtime uptake for Temperate North America. In addition, significantly larger seasonal cycles are obtained for some ocean regions, such as the Northern Ocean, North Pacific, North Atlantic and Western Equatorial Pacific, regions that appear to be well-resolved by the inversion
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