Portable x-ray fluorescence spectrometer for environmental monitoring of inorganic pollutants

A portable x-ray fluorescence spectrometer has a portable sensor unit containing a battery, a high voltage power supply, an x-ray tube which produces a beam x-ray radiation directed toward a target sample, and a detector for fluorescent x-rays produced by the sample. If a silicon-lithium detector is used, the sensor unit also contains either a thermoelectric or thermochemical cooler, or a small dewar flask containing liquid nitrogen to cool the detector. A pulse height analyzer (PHA) generates a spectrum of data for each sample consisting of the number of fluorescent x-rays detected as a function of their energy level. The PHA can also store spectrum data for a number of samples in the field. A processing unit can be attached to the pulse height analyzer to upload and analyze the stored spectrum data for each sample. The processing unit provides a graphic display of the spectrum data for each sample, and provides qualitative and/or quantitative analysis of the elemental composition of the sample by comparing the peaks in the sample spectrum against known x-ray energies for various chemical elements. An optional filtration enclosure can be used to filter particles from a sample suspension, either in the form of a natural suspension or a chemically created precipitate. The sensor unit is then temporarily attached to the filtration unit to analyze the particles collected by the filter medium

Sub-daily Statistical Downscaling of Meteorological Variables Using Neural Networks

AbstractA new open source neural network temporal downscaling model is described and tested using CRU-NCEP reanal ysis and CCSM3 climate model output. We downscaled multiple meteorological variables in tandem from monthly to sub-daily time steps while also retaining consistent correlations between variables. We found that our feed forward, error backpropagation approach produced synthetic 6 hourly meteorology with biases no greater than 0.6% across all variables and variance that was accurate within 1% for all variables except atmospheric pressure, wind speed, and precipitation. Correlations between downscaled output and the expected (original) monthly means exceeded 0.99 for all variables, which indicates that this approach would work well for generating atmospheric forcing data consistent with mass and energy conserved GCM output. Our neural network approach performed well for variables that had correlations to other variables of about 0.3 and better and its skill was increased by downscaling multiple correlated variables together. Poor replication of precipitation intensity however required further post-processing in order to obtain the expected probability distribution. The concurrence of precipitation events with expected changes in sub ordinate variables (e.g., less incident shortwave radiation during precipitation events) were nearly as consistent in the downscaled data as in the training data with probabilities that differed by no more than 6%. Our downscaling approach requires training data at the target time step and relies on a weak assumption that climate variability in the extrapolated data is similar to variability in the training data

Automated Synthesis of Quantum Subcircuits

The quantum computer has become contemporary reality, with the first two-qubit machine of mere decades ago transforming into cloud-accessible devices with tens, hundreds, or--in a few cases--even thousands of qubits. While such hardware is noisy and still relatively small, the increasing number of operable qubits raises another challenge: how to develop the now-sizeable quantum circuits executable on these machines. Preparing circuits manually for specifications of any meaningful size is at best tedious and at worst impossible, creating a need for automation. This article describes an automated quantum-software toolkit for synthesis, compilation, and optimization, which transforms classically-specified, irreversible functions to both technology-independent and technology-dependent quantum circuits. We also describe and analyze the toolkit's application to three situations--quantum read-only memories, quantum random number generators, and quantum oracles--and illustrate the toolkit's start-to-finish features from the input of classical functions to the output of quantum circuits ready-to-run on commercial hardware. Furthermore, we illustrate how the toolkit enables research beyond circuit synthesis, including comparison of synthesis and optimization methods and deeper understanding of even well-studied quantum algorithms. As quantum hardware continues to develop, such quantum circuit toolkits will play a critical role in realizing its potential.Comment: 49 pages, 25 figures, 20 table

A fast radio burst with a low dispersion measure

Fast radio bursts (FRBs) are millisecond pulses of radio emission of seemingly extragalactic origin. More than 50 FRBs have now been detected, with only one seen to repeat. Here we present a new FRB discovery, FRB 110214, which was detected in the high latitude portion of the High Time Resolution Universe South survey at the Parkes telescope. FRB 110214 has one of the lowest dispersion measures of any known FRB (DM = 168.9$\pm$0.5 pc cm$^{-3}$), and was detected in two beams of the Parkes multi-beam receiver. A triangulation of the burst origin on the sky identified three possible regions in the beam pattern where it may have originated, all in sidelobes of the primary detection beam. Depending on the true location of the burst the intrinsic fluence is estimated to fall in the range of 50 -- 2000 Jy ms, making FRB 110214 one of the highest-fluence FRBs detected with the Parkes telescope. No repeating pulses were seen in almost 100 hours of follow-up observations with the Parkes telescope down to a limiting fluence of 0.3 Jy ms for a 2-ms pulse. Similar low-DM, ultra-bright FRBs may be detected in telescope sidelobes in the future, making careful modeling of multi-beam instrument beam patterns of utmost importance for upcoming FRB surveys.Comment: 8 pages, 3 figures, accepted for publication in MNRA

Comparison of pretreatment characteristics and treatment outcomes for alcohol-, cocaine-, and multisubstance-dependent patients.

We investigated whether pretreatment characteristics and measures of outcome differed for alcohol-, cocaine-, and multisubstance-dependent patients receiving outpatient substance abuse treatment. One hundred and forty substance dependent individuals (32 alcohol, 76 cocaine, and 32 multisubstance) enrolled in a 12-week outpatient treatment program were compared across measures of addiction severity, personality, and treatment-readiness at admission. In-treatment, end-of-treatment and 9-month follow-up assessments of treatment outcome were then compared across the three groups. Outcome measures included reduction in problem severity, abstinence, retention, number of sessions attended, dropout, and counselor and patient ratings of treatment benefit. At admission, the multisubstance group had a higher proportion of positive urines, reported more severe drug, alcohol and psychiatric problems, and displayed higher impulsivity and anxiety scores than one or both of the other groups. However, multisubstance patients were more treatment ready in terms of adopting a total abstinence orientation than alcohol or cocaine patients. While a significant reduction in symptoms occurred for the total sample during treatment as well as at follow-up, comparisons of outcomes did not consistently favor any particular group. The three groups had equivalent improvements in eleven of fourteen during-treatment and five of seven follow-up measures. Despite pretreatment differences, in severity and treatment-readiness, outcomes were more similar than different for alcohol-, cocaine-, and multisubstance-dependent patients. Clinicians should be cautious about forecasting treatment-outcomes for addicted patients based on their primary substances of abuse

Applying a resources framework to analysis of the Force and Motion Conceptual Evaluation

We suggest one redefinition of common clusters of questions used to analyze student responses on the Force and Motion Conceptual Evaluation (FMCE). Our goal is to move beyond the expert/novice analysis of student learning based on pre-/post-testing and the correctness of responses (either on the overall test or on clusters of questions defined solely by content). We use a resources framework, taking special note of the contextual and representational dependence of questions with seemingly similar physics content. We analyze clusters in ways that allow the most common incorrect answers to give as much, or more, information as the correctness of responses in that cluster. Furthermore, we show that false positives can be found, especially on questions dealing with Newton's Third Law.Comment: 13 pages, 7 figures, submitted to Phys. Rev. ST Phys. Educ. Res; Revised: 12 pages, 9 figures, submitted to Phys. Rev. ST Phys. Educ. Res., altered content and focu

Heterogeneous N2O5 Uptake During Winter: Aircraft Measurements During the 2015 WINTER Campaign and Critical Evaluation of Current Parameterizations

Nocturnal dinitrogen pentoxide (N2O5) heterogeneous chemistry impacts regional air quality and the distribution and lifetime of tropospheric oxidants. Formed from the oxidation of nitrogen oxides, N2O5 is heterogeneously lost to aerosol with a highly variable reaction probability, γ(N2O5), dependent on aerosol composition and ambient conditions. Reaction products include soluble nitrate (HNO3 or NO3−) and nitryl chloride (ClNO2). We report the first‐ever derivations of γ(N2O5) from ambient wintertime aircraft measurements in the critically important nocturnal residual boundary layer. Box modeling of the 2015 Wintertime INvestigation of Transport, Emissions, and Reactivity (WINTER) campaign over the eastern United States derived 2,876 individual γ(N2O5) values with a median value of 0.0143 and range of 2 × 10−5 to 0.1751. WINTER γ(N2O5) values exhibited the strongest correlation with aerosol water content, but weak correlations with other variables, such as aerosol nitrate and organics, suggesting a complex, nonlinear dependence on multiple factors, or an additional dependence on a nonobserved factor. This factor may be related to aerosol phase, morphology (i.e., core shell), or mixing state, none of which are commonly measured during aircraft field studies. Despite general agreement with previous laboratory observations, comparison of WINTER data with 14 literature parameterizations (used to predict γ(N2O5) in chemical transport models) confirms that none of the current methods reproduce the full range of γ(N2O5) values. Nine reproduce the WINTER median within a factor of 2. Presented here is the first field‐based, empirical parameterization of γ(N2O5), fit to WINTER data, based on the functional form of previous parameterizations

PITTSBURGH’S RACIAL DEMOGRAPHICS: DIFFERENCES AND DISPARITIES

Pittsburgh’s Racial Demographics: Differences and Disparities provides indicators of quality of life by race and ethnicity in the Pittsburgh region. Data are provided for four groups (Whites, African Americans, Asians, and Hispanics) and for four geographic areas (city of Pittsburgh, Allegheny County, Pittsburgh Metropolitan Statistical Area, and the U.S.). The most recent data available for the Pittsburgh area and the nation were used in this report. In some instances, however, only data from the 2000 census were available to make comparisons. It is also the case that data were not available on all of our topic areas in the same years. It is our hope to update this report every three years, particularly if the American Community Survey (which is designed to replace the decennial census) produces regular, reliable data by race for cities, counties, and regions

Highly purified human-derived follicle-stimulating hormone (Bravelle®) has equivalent efficacy to follitropin-beta (Follistim ®) in infertile women undergoing in vitro fertilization

BACKGROUND: These data compare the efficacy and safety of highly purified human-derived follicle-stimulating hormone (Bravelle(R)) and recombinant follitropin-β (Follistim(R)) in women undergoing in vitro fertilization. METHODS: This report describes the pooled data from two, nearly identical, randomized, controlled, parallel-group, multicenter studies conducted in a total of 19 academic and private IVF-ET centers in the United States. Infertile premenopausal women underwent pituitary down-regulation using leuprolide acetate followed by a maximum of 12 days of subcutaneous Bravelle(R) (n = 120) or Follistim(R) (n = 118), followed by administration of human chorionic gonadotropin, oocyte retrieval and embryo transfer. The primary efficacy measure was the mean number of oocytes retrieved; secondary efficacy measures included the total dose and duration of gonadotropin treatment; peak serum estradion levels; embryo transfer and implantation rates; chemical, clinical and continuing pregnancies; and live birth rates. All adverse events were recorded and injection site pain was recorded daily using a patient, self-assessment diary. RESULTS: Similar efficacy responses were observed for all outcome parameters in the two treatment groups. Although patients receiving Bravelle(R) consistently reported a greater number of chemical, clinical and continuing pregnancies, as well as an increased rate of live birth, the data did not attain statistical significance (P > 0.05). The overall incidence of adverse events was similar in both groups, but compared to Follistim(R), injections of Bravelle(R) were reported by patients to be significantly less painful (P < 0.001). CONCLUSIONS: Bravelle(R) and Follistim(R) had comparable efficacy in controlled ovarian hyperstimulation in women undergoing IVF-ET. There were no differences in the nature or number of adverse events between the treatment groups although Bravelle(R) injections were reported to be significantly less painful

With or without spikes: localization of focal epileptic activity by simultaneous electroencephalography and functional magnetic resonance imaging

In patients with medically refractory focal epilepsy who are candidates for epilepsy surgery, concordant non-invasive neuroimaging data are useful to guide invasive electroencephalographic recordings or surgical resection. Simultaneous electroencephalography and functional magnetic resonance imaging recordings can reveal regions of haemodynamic fluctuations related to epileptic activity and help localize its generators. However, many of these studies (40-70%) remain inconclusive, principally due to the absence of interictal epileptiform discharges during simultaneous recordings, or lack of haemodynamic changes correlated to interictal epileptiform discharges. We investigated whether the presence of epilepsy-specific voltage maps on scalp electroencephalography correlated with haemodynamic changes and could help localize the epileptic focus. In 23 patients with focal epilepsy, we built epilepsy-specific electroencephalographic voltage maps using averaged interictal epileptiform discharges recorded during long-term clinical monitoring outside the scanner and computed the correlation of this map with the electroencephalographic recordings in the scanner for each time frame. The time course of this correlation coefficient was used as a regressor for functional magnetic resonance imaging analysis to map haemodynamic changes related to these epilepsy-specific maps (topography-related haemodynamic changes). The method was first validated in five patients with significant haemodynamic changes correlated to interictal epileptiform discharges on conventional analysis. We then applied the method to 18 patients who had inconclusive simultaneous electroencephalography and functional magnetic resonance imaging studies due to the absence of interictal epileptiform discharges or absence of significant correlated haemodynamic changes. The concordance of the results with subsequent intracranial electroencephalography and/or resection area in patients who were seizure free after surgery was assessed. In the validation group, haemodynamic changes correlated to voltage maps were similar to those obtained with conventional analysis in 5/5 patients. In 14/18 patients (78%) with previously inconclusive studies, scalp maps related to epileptic activity had haemodynamic correlates even when no interictal epileptiform discharges were detected during simultaneous recordings. Haemodynamic changes correlated to voltage maps were spatially concordant with intracranial electroencephalography or with the resection area. We found better concordance in patients with lateral temporal and extratemporal neocortical epilepsy compared to medial/polar temporal lobe epilepsy, probably due to the fact that electroencephalographic voltage maps specific to lateral temporal and extratemporal epileptic activity are more dissimilar to maps of physiological activity. Our approach significantly increases the yield of simultaneous electroencephalography and functional magnetic resonance imaging to localize the epileptic focus non-invasively, allowing better targeting for surgical resection or implantation of intracranial electrode array