TOF-SIMS for Rapid Nuclear Forensics Evaluation of Uranium Oxide Particles

Because of nuclear proliferation concerns, nuclear material must be safeguarded, and peaceful intentions verified. The field of nuclear forensics addresses these concerns. While established nuclear forensic techniques exist, quicker, more accurate and less expensive methods are of interest for nonproliferation applications. Currently a host of different analytical techniques, requiring a week or longer, are employed to obtain isotopic ratios, chemical abundances and morphology for forensic particulate samples. Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) is a candidate technology for rapid evaluation of these properties for small amounts of nuclear materials. After a thorough investigation, this study found TOF-SIMS to be particularly useful to the nuclear forensic field as a triage technique, capable of quickly identifying and roughly assessing uranium containing materials for these properties. Uranium isotopic abundances can be determined to an accuracy of 1 percent. Uranium oxide particles are clearly distinguished from one another. TOF-SIMS imaging easily and quickly reveals the basic shape and composition of particles. Additionally the relative abundances of various secondary ions produced with TOF-SIMS may uncover new information on fundamental uranium oxide structures and properties

Network Lasso: Clustering and Optimization in Large Graphs

Convex optimization is an essential tool for modern data analysis, as it provides a framework to formulate and solve many problems in machine learning and data mining. However, general convex optimization solvers do not scale well, and scalable solvers are often specialized to only work on a narrow class of problems. Therefore, there is a need for simple, scalable algorithms that can solve many common optimization problems. In this paper, we introduce the \emph{network lasso}, a generalization of the group lasso to a network setting that allows for simultaneous clustering and optimization on graphs. We develop an algorithm based on the Alternating Direction Method of Multipliers (ADMM) to solve this problem in a distributed and scalable manner, which allows for guaranteed global convergence even on large graphs. We also examine a non-convex extension of this approach. We then demonstrate that many types of problems can be expressed in our framework. We focus on three in particular - binary classification, predicting housing prices, and event detection in time series data - comparing the network lasso to baseline approaches and showing that it is both a fast and accurate method of solving large optimization problems

Salmon-derived nitrogen in terrestrial invertebrates from coniferous forests of the Pacific Northwest

BACKGROUND: Bi-directional flow of nutrients between marine and terrestrial ecosystems can provide essential resources that structure communities in transitional habitats. On the Pacific coast of North America, anadromous salmon (Oncorhynchus spp.) constitute a dominant nutrient subsidy to aquatic habitats and riparian vegetation, although the contribution to terrestrial habitats is not well established. We use a dual isotope approach of δ(15)N and δ(13)C to test for the contribution of salmon nutrients to multiple trophic levels of litter-based terrestrial invertebrates below and above waterfalls that act as a barrier to salmon migration on two watersheds in coastal British Columbia. RESULTS: Invertebrates varied predictably in δ(15)N with enrichment of 3–8‰ below the falls compared with above the falls in all trophic groups on both watersheds. We observed increasing δ(15)N levels in our invertebrate groups with increasing consumption of dietary protein. Invertebrates varied in δ(13)C but did not always vary predictably with trophic level or habitat. From 19.4 to 71.5% of invertebrate total nitrogen was originally derived from salmon depending on taxa, watershed, and degree of fractionation from the source. CONCLUSIONS: Enrichment of δ(15)N in the invertebrate community below the falls in conjunction with the absence of δ(13)C enrichment suggests that enrichment in δ(15)N occurs primarily through salmon-derived nitrogen subsidies to litter, soil and vegetation N pools rather than from direct consumption of salmon tissue or salmon tissue consumers. Salmon nutrient subsidies to terrestrial habitats may result in shifts in invertebrate community structure, with subsequent implications for higher vertebrate consumers, particularly the passerines

Cluster-randomised Controlled Trial of an Occupational Therapy Group Intervention for Children Designed to Promote Emotional Wellbeing: Study Protocol

Background Symptoms of anxiety and depression are common in childhood, as are risk factors that undermine wellbeing: low self-esteem and limited participation in daily occupations. Current treatments focus primarily on modifying internal cognitions with insufficient effect on functional outcomes. Occupational therapists have a role in measuring and enabling children’s functional abilities to promote health and wellbeing. To-date there is no evidence for the use of occupational therapy as an intervention to promote mental health or increase self-esteem, participation and wellbeing in a preventative context. The aim of this cluster-randomised controlled study is to investigate the effectiveness of an 8-week occupational therapy group intervention (Kia Piki te Hauora) at reducing symptoms of anxiety and depression and improving self-esteem, participation and wellbeing in children aged 11–13 years. Methods/design In this two-arm, pragmatic, cluster-randomised controlled trial, 154 children will be recruited from 14 schools. All mainstream schools in the region will be eligible and a convenience sample of 14 schools, stratified by decile ranking (i.e. low, medium, and high) will be recruited. Eight to twelve students aged 11–13 years from each school will be recruited by senior school personnel. Following consent, schools will be randomised to either the intervention or waitlist control arm of the trial. The study will employ a parallel and one-way waitlist-to-intervention crossover design. Each cluster’s involvement will last up to 19 or 31 weeks depending on allocation to the intervention or waitlist respectively. The primary outcome is symptoms of anxiety and secondary outcomes are symptoms of depression, self-esteem, participation in daily occupations and wellbeing. Outcome measurement will be repeated at baseline, post-intervention and again at 8–9 weeks follow-up. Planned statistical analyses will utilise repeated measures analysis of covariance. The primary analysis will be based on an intention-to-treat analysis set and include only parallel data. The crossover data will only be used in secondary analyses. Discussion This is the first cluster-randomised controlled trial to investigate an occupational therapy intervention promoting emotional wellbeing in a non-clinical sample of children. Results will contribute to the limited evidence base for occupational therapists in this field and potentially support investment in these services. Trial registration Australia/New Zealand Clinical Trials Register: ACTRN12614000453684

Quality and reporting of cluster randomised controlled trials evaluating occupational therapy interventions: A systematic review

Background: Growing use of the cluster randomised control trials (RCTs) in healthcare research requires careful attention to study designs, with implications for the development of an evidence-base for practice. Objective: To investigate the characteristics, quality and reporting of cluster-RCTs evaluating occupational therapy interventions to inform future research design. Methods: An extensive search of cluster-RCTs evaluating occupational therapy was conducted in several databases. Results: Fourteen studies met our inclusion criteria; four were protocols. Eleven (79%) justified the use of a cluster-RCT and accounted for clustering in the sample size and analysis. All full studies reported the number of clusters randomised and five reported ICCs (50%): protocols had higher compliance. Risk of bias was most evident in blinding of participants. Statistician involvement was associated with improved trial quality and reporting. Conclusions: Quality of cluster-RCTs of occupational therapy interventions is comparable to those from other areas of health research and needs improvement

An automatic taxonomy of galaxy morphology using unsupervised machine learning

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2017 the Author (s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reservedWe present an unsupervised machine learning technique that automatically segments and labels galaxies in astronomical imaging surveys using only pixel data. Distinct from previous unsupervised machine learning approaches used in astronomy we use no pre-selection or pre-filtering of target galaxy type to identify galaxies that are similar. We demonstrate the technique on the Hubble Space Telescope (HST) Frontier Fields. By training the algorithm using galaxies from one field (Abell 2744) and applying the result to another (MACS 0416.1-2403), we show how the algorithm can cleanly separate early and late type galaxies without any form of pre-directed training for what an 'early' or 'late' type galaxy is. We then apply the technique to the HST Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) fields, creating a catalogue of approximately 60 000 classifications. We show how the automatic classification groups galaxies of similar morphological (and photometric) type and make the classifications public via a catalogue, a visual catalogue and galaxy similarity search. We compare the CANDELS machine-based classifications to human-classifications from the Galaxy Zoo: CANDELS project. Although there is not a direct mapping between Galaxy Zoo and our hierarchical labelling, we demonstrate a good level of concordance between human and machine classifications. Finally, we show how the technique can be used to identify rarer objects and present lensed galaxy candidates from the CANDELS imaging.Peer reviewe

The growth of leading-edge distortions on a viscous sheet

The results of a set of experiments to determine some features of the undulations that develop on the leading edge of a sheet of fluid on an inclined plane are presented. A range of fluid viscosities, fluid volumes, and plate angles was used. In nearly all the cases, the observed disturbances had a triangular or sawtooth shape, with only a single example of a finger or parallel-sided shape appearing. The power-law exponents for the position down the plate of both the tips of the disturbances and their roots, that is, the points where they join the uniform sheet above them, were calculated from a series of photographs, and the corresponding wavelengths measured. The exponents are broadly in line with those that can be deduced from a simple model including viscosity, gravity, and volume flux, and ignoring all capillary effects. This conclusion suggests that the criterion for distinguishing the two types of disturbance does not depend on the global dynamics of the developing structures, and that a detailed analysis of the tip and root regions, where capillarity will be significant, is needed for further progress to be made. © 1999 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70941/2/PHFLE6-11-2-307-1.pd

Hydrodynamic theory of de-wetting

A prototypical problem in the study of wetting phenomena is that of a solid plunging into or being withdrawn from a liquid bath. In the latter, de-wetting case, a critical speed exists above which a stationary contact line is no longer sustainable and a liquid film is being deposited on the solid. Demonstrating this behavior to be a hydrodynamic instability close to the contact line, we provide the first theoretical explanation of a classical prediction due to Derjaguin and Levi: instability occurs when the outer, static meniscus approaches the shape corresponding to a perfectly wetting fluid

Measurement Characteristics of Athlete Monitoring Tools in Professional Australian Football.

PURPOSE:To examine the measurement reliability and sensitivity of common athlete monitoring tools in professional Australian Football players. METHODS:Test-retest reliability (noise) and weekly variation (signal) data were collected from 42 professional Australian footballers from 1 club during a competition season. Perceptual wellness was measured via questionnaires completed before main training sessions (48, 72, and 96 h postmatch), with players providing a rating (1-5 Likert scale) regarding their muscle soreness, sleep quality, fatigue level, stress, and motivation. Eccentric hamstring force and countermovement jumps were assessed via proprietary systems once per week. Heart rate recovery was assessed via a standard submaximal run test on a grass-covered field with players wearing a heart rate monitor. The heart rate recovery was calculated by subtracting average heart rate during final 10 seconds of rest from average heart rate during final 30 seconds of exercise. Typical test error was reported as coefficient of variation percentage (CV%) and intraclass coefficients. Sensitivity was calculated by dividing weekly CV% by test CV% to produce a signal to noise ratio. RESULTS:All measures displayed acceptable sensitivity. Signal to noise ratio ranged from 1.3 to 11.1. Intraclass coefficients ranged from .30 to .97 for all measures. CONCLUSIONS:The heart rate recovery test, countermovement jump test, eccentric hamstring force test, and perceptual wellness all possess acceptable measurement sensitivity. Signal to noise ratio analysis is a novel method of assessing measurement characteristics of monitoring tools. These data can be used by coaches and scientists to identify meaningful changes in common measures of fitness and fatigue in professional Australian football