2,466 research outputs found
Micro-Analysis of D/H Ratios in Mantle Minerals by Carrier-Gas Mass Spectrometry
Isotopic analysis of water released
by vacuum heating of hydrous minerals and sub-marine
basaltic glasses indicates that they vary in δD_(SMOW)
between ca. +10 and -115 per mil (e.g., [1]). However,
with few exceptions variations within that range are not
well correlated with other geochemical and geologic
properties and it is debated whether they reflect isotopic
heterogeneity in the mantle, fractionations produced
during ascent to the surface, or sub-solidus alteration.
This ambiguity is at least partly due to the
large sample size and slow rate of conventional analyses,
which precludes linking isotopic ranges to grain-scale
petrographic variables or constructing large data
bases (many 10’s of samples) in a reasonable period of
time. Ion microprobe methods provide one solution to
these problems, although they suffer from analytical
uncertainties nominally 5 to 10 times worse than conventional
measurements and large fractionations that
can be a source of systematic error
A robust procedure for the measurement of Serum Magnesium on the Hitachi 704 using Calmagite
peer-reviewedA robust procedure for measurement of magnesium in serum is described using calmagite in CAPS buffer at pH 11.5. Interference from other magnesium reagents was reduced and evaluated for chromophoric interference. The procedure was not effected by bilirubin or hemoglobin in serum samples
The new control system of the SPS target sector
The SPS, the Super Proton Synchrotron at CERN, is an accelerator originally designed and commissioned in 1976 for protons. The control system of the SPS target stations, beam absorbers and other aperture limiting devices was developed in the seventies. It was mainly based on home made electronics and equipment dependent software. With time, this electronics has become obsolete, difficult to maintain in operation and not suitable for integration into a modern control system. In 1997, a project was set up to modernise the electronics and the related software. The new control system is largely based on standard industrial hardware and software components. SIEMENS Simatic S7-300 programmable logic controllers have been used as equipment controllers and connected through PROFIBUS to a Windows-NT front-end PC running the SIEMENS WinCC SCADA package which acts as local controller and remote access gateway. This fully industrial solution has been successfully integrated into the actual SPS accelerator control infrastructure and is open to other industrial communication protocols. The design, development and realisation of the selected solution have been outsourced to industry
Using privacy calculus theory to explore entrepreneurial directions in mobile location-based advertising: Identifying intrusiveness as the critical risk factor
Location-based advertising is an entrepreneurial and innovative means for advertisers to reach out through
personalised messages sent directly to mobile phones using their geographic location. The mobile phone users'
willingness to disclose their location and other personal information is essential for the successful im-
plementation of mobile location-based advertising (MLBA). Despite the potential enhancement of the user ex-
perience through such personalisation and the improved interaction with the marketer, there is an increasing
tension between that personalisation and mobile users' concerns about privacy. While the privacy calculus
theory (PCT) suggests that consumers make privacy-based decisions by evaluating the benefits any information
may bring against the risk of its disclosure, this study examines the specific risks and benefits that influence
consumers' acceptance of MLBA. A conceptual model is proposed based on the existing literature and a stan-
dardised survey was developed and targeted at individuals with known interests in the subject matter. From
these requests, 252 valid responses were received and used to evaluate the key benefits and risks of MLBA from
the users' perspectives. While the results confirmed the importance of internet privacy concerns (IPC) as an
important determinant, they also indicate that monetary rewards and intrusiveness have a notably stronger
impact on acceptance intentions towards MLBA. Intrusiveness is the most important risk factor in determining
mobile users' intentions to accept MLBA and therefore establishing effective means of minimising the perceived
intrusiveness of MLBA can be expected to have the greatest impact on achieving effective communications with
mobile phone users
A new method of prenatal alcohol classification accounting for dose, pattern, and timing of exposure: Improving our ability to examine fetal effects from low to moderate exposure
Background: When examining the association between prenatal alcohol exposure and fetal effects, the timing and intensity of exposure have been ignored in epidemiological studies. The effect of using dose, pattern and timing of consumption (“composite” method) was investigated in this study, to examine the association between prenatal alcohol exposure and fetal effects. Methods: The composite method resulted in six categories of exposure (abstinent, low, moderate, binge <weekly, binge 1–2×/week and heavy). The odds of language delay and child behaviour problems were calculated for the composite method and then compared with an analysis using averaged estimates of <1 and 1+ drinks per day and with stratification by quantity ignoring dose per occasion. Data used for the analyses were from a 10% random sample of non-Indigenous women delivering a live infant in Western Australia (1995–1997). Participants from the 1995-1996 cohort were invited to participate in an 8-year longitudinal survey (78% response rate n=2224; 85% were followed-up at 2 years, 73% at 5 years and 61% at 8 years). Results: The effect of moderate and binge levels of exposure was only evident with the composite method; anxiety/depression following first-trimester moderate exposure (OR 2.24, 95% CI 1.16 to 4.34), and following late pregnancy moderate (aggressive behaviour OR 1.93, 95% CI 0.91 to 4.09) and binge (language delay OR 3.00, 95% CI 0.90 to 9.93) exposures. Results for heavy levels of exposure were similar with each method. The estimates for late pregnancy were imprecise due to small numbers. Conclusion: The composite method of classification more closely reflects real-life drinking patterns and better discriminates maternal drinking than the other methods, particularly low, moderate and binge levels
Shot-noise-limited spin measurements in a pulsed molecular beam
Heavy diatomic molecules have been identified as good candidates for use in
electron electric dipole moment (eEDM) searches. Suitable molecular species can
be produced in pulsed beams, but with a total flux and/or temporal evolution
that varies significantly from pulse to pulse. These variations can degrade the
experimental sensitivity to changes in spin precession phase of an electri-
cally polarized state, which is the observable of interest for an eEDM
measurement. We present two methods for measurement of the phase that provide
immunity to beam temporal variations, and make it possible to reach
shot-noise-limited sensitivity. Each method employs rapid projection of the
spin state onto both components of an orthonormal basis. We demonstrate both
methods using the eEDM-sensitive H state of thorium monoxide (ThO), and use one
of them to measure the magnetic moment of this state with increased accuracy
relative to previous determinations.Comment: 12 pages, 6 figure
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Visual Field Progression in Glaucoma What Is the Specificity of the Guided Progression Analysis?
Purpose: To estimate the specificity of the Guided Progression Analysis (GPA) (Carl Zeiss Meditec, Dublin, CA) in individual patients with glaucoma.
Design: Observational cohort study.
Participants: Thirty patients with open-angle glaucoma.
Methods: In 30 patients with open-angle glaucoma, 1 eye (median mean deviation [MD], −2.5 decibels [dB]; interquartile range, −4.4 to −1.3 dB) was tested 12 times over 3 months (Humphrey Field Analyzer, Carl Zeiss Meditec; SITA Standard, 24-2). “Possible progression” and “likely progression” were determined with the GPA. These analyses were repeated after the order of the tests had been randomly rearranged (1000 unique permutations).
Main Outcome Measures: Rate of false-positive alerts of “possible progression” and “likely progression” with the GPA.
Results: On average, the specificity of the GPA “likely progression” alert was high—for the entire sample, the mean rate of false-positive alerts after 10 follow-up tests was 2.6%. With “possible progression,” the specificity was considerably lower (false-positive rate, 18.5%). Most important, the cumulative rate of false-positive alerts varied substantially among patients, from 0.31, P≤0.10).
Conclusions: On average, progression criteria currently used in the GPA have high specificity, but some patients are more likely to show false-positive alerts than others. This is a natural consequence of population-based change criteria and may not matter in clinical trials and studies in which large groups of patients are compared. However, it must be considered when the GPA is used in clinical practice where specificity needs to be controlled for individual patients
Revisiting battistini: Pleistocene coastal evolution of southwestern madagascar
The study of paleo shorelines, particularly of those formed during the late Quaternary, provides robust insights into past climate variability. Advances in surveying techniques and chronological methodologies have dramatically improved the inter-comparability of regional and basin-wide paleo shoreline surveys. However, these advances have been applied unevenly across the globe. This is especially true in southwestern Madagascar, where, in the 1960s and 1970s, emerged Pleistocene beach and reef facies were first described in detail and dated to Marine Isotope Stage (MIS) 5a using U–Th alpha activity counting by french geologist René Battistini. Now, 50 years on, no further analysis of the coastal sequence has been made. In this study, we present an updated late Pleistocene coastal evolution model for the southwestern Madagascar coast. Utilizing a combination of Structure-from-Motion/Multi-View Stereo techniques and differential Global Navigation Satellite System surveys, we have created five high-resolution 3D outcrop reconstructions that have, in turn, been chronologically constrained using 10 U-series ages from both in situ and reworked coral samples. Our data suggest that the emerged reef was deposited during MIS 5e (∼125 ka), then was covered by intertidal and beach sediment (including redeposited coral clasts of MIS 5e age), and finally capped off by thick eolianites. This sequence would suggest that the local sea level must have remained stable throughout MIS 5e in order to allow for the progradation of both the beach and reef environments
Wireless Attenuation by Energy Efficient Windows in the 8-12.5 GHz region
Measurements are presented of wireless propagation into buildings via standard double glazing and via heat isolating (Low Emissivity) double glazing in the region 8-12.5GHz.
Standard double glazing attenuates the signal in line with results published elsewhere.
Heat energy efficient double glazing, however, at least 20dB more than the standard glazing of the signal does not pass. The reason for this poor propagation is outlined and a
propagation model for the heat isolation window is presented
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