Detrital U-Pb geochronology provenance analyses: case studies in the Greater Green River Basin, Wyoming, and the Book Cliffs, Utah

Heavy mineral modal abundances and U-Pb geochronology are used to determine sediment provenance, provenance changes through time, and timing of crustal exhumation. Optimal preparation of datable detrital minerals (zircon, rutile, monazite, etc.) for provenance research using U-Pb geochronology has been a subject of debate and concern. Potential biases that are a concern consist of preferentially including or excluding datable detrital grains during mineral separation and data processing techniques. Exclusion of grains can lead to under- representation of source areas for a given sedimentary unit and alter the U-Pb age signature. The purpose of this study is to provide insight into this potential biasing by performing Laser Ablation-Inductively Coupled Plasma-Mass Spectrometer (LA-ICP-MS) U-Pb analyses of rutile and zircon with an optimized mineral separation and grain selection procedure. The Quantitative Evaluation of Minerals by SCANning electron microscopy (QEMSCAN®) was thus used to provide insight into potential biasing by automated quantification of modal abundances of minerals. A reliable technique for sample preparation was developed based on the LA-ICP-MS U-Pb analyses and QEMSCAN® mineralogical data. This technique includes minimal separation steps without preferential loss of mineral grains, representative sample splitting, and random and representative selection of grains to be dated. The result is a more comprehensive dataset for provenance analysis. The Late Cretaceous sedimentary rocks of the Pine Ridge Sandstone and Almond Formation of the Mesaverde Group, Lewis Shale and Fox Hills Sandstone in the Greater Green River Basin, Rawlins, Wyoming, were investigated to test and develop mineral separation techniques. The methods developed here were also used to test whether there are variations in U- Pb provenance signal and modal mineralogy due to changes in depositional facies using samples from the Upper Cretaceous Blackhawk Formation and Castlegate Sandstone from the Book Cliffs, Utah. These stratal units were selected because while the age of the potential source areas are well known and the sequence stratigraphy, and sedimentology of the strata is well characterized, provenance has not been determined. The results from LA-ICP-MS and QEMCAN analyses of Greater Green River Basin sedimentary rocks show that standard mineral separation procedures are not ideal for detrital provenance investigations. The standard mineral separation procedures introduce bias, resulting in a misrepresentation of the modal mineralogy and provenance age signal. LA-ICP-MS and QEMSCAN analyses of sedimentary samples from the Book Cliffs, Utah show that there are variations in the U-Pb provenance signal and modal mineralogy between samples from different depositional facies

Mit is játsszunk ma?

Die Titelfrage mag auf den ersten Blick wie eine Kinderfrage erscheinen, da wir unsere Tage mit vorgegebenen und vorgeschriebenen Aufgaben anfüllen. Wir fühlen uns, als ob uns der Luxus des Spielens gar nicht erlaubt sein dürfte. Worauf kommt es eigentlich an? Was soll der Mensch tun, damit es sinnvoll und wertvoll ist, sein Tun? Nach Lipperts Antwort wäre unser Tun der Mühe wert, wenn es eine Nachbildung und Fortsetzung der göttlichen Arbeit, der Weisheit Gottes darstellen würde. Ein solches Tun wäre dann auch ein schöpferisches Tun und ein Wohltun. Man würde von dem Ergebnis unseres Tuns sagen können, was Gott selbst von den Werken seiner Hände sagen durfte: Siehe, sie waren gut, sie waren sehr gut. Es müsste ein schönes Schaffen und ein frohes Arbeiten sein, wenn wir zu all dem, was da ist, etwas hinzutun dürften. Diese Weisheit Gottes ist doch nach der Bezeugung der Heiligen Schrift eine spielende! Die Titelfrage sei also nicht kindisch, sondern kindlich. Spiel ist eben keine Trägheit, es ist vielmehr höchste Kraft. Lipperts Essay aus den dreissiger Jahren des 20. Jahrhunderts ermutigt uns, unser ganzes Leben einfach gewähren zu lassen – trotz aller Last, Not und Leid, durch die wir uns ebenfalls Gott nähern – und es wie ein grosses Spiel zu erleben

Effect of feedback on delaying deterioration in quality of compressions during 2 minutes of continuous chest compressions: a randomized manikin study investigating performance with and without feedback

<p>Abstract</p> <p>Background</p> <p>Good quality basic life support (BLS) improves outcome following cardiac arrest. As BLS performance deteriorates over time we performed a parallel group, superiority study to investigate the effect of feedback on quality of chest compression with the hypothesis that feedback delays deterioration of quality of compressions.</p> <p>Methods</p> <p>Participants attending a national one-day conference on cardiac arrest and CPR in Denmark were randomized to perform single-rescuer BLS with (n = 26) or without verbal and visual feedback (n = 28) on a manikin using a ZOLL AED plus. Data were analyzed using Rescuenet Code Review. Blinding of participants was not possible, but allocation concealment was performed. Primary outcome was the proportion of delivered compressions within target depth compared over a 2-minute period within the groups and between the groups. Secondary outcome was the proportion of delivered compressions within target rate compared over a 2-minute period within the groups and between the groups. Performance variables for 30-second intervals were analyzed and compared.</p> <p>Results</p> <p>24 (92%) and 23 (82%) had CPR experience in the group with and without feedback respectively. 14 (54%) were CPR instructors in the feedback group and 18 (64%) in the group without feedback. Data from 26 and 28 participants were analyzed respectively. Although median values for proportion of delivered compressions within target depth were higher in the feedback group (0-30 s: 54.0%; 30-60 s: 88.0%; 60-90 s: 72.6%; 90-120 s: 87.0%), no significant difference was found when compared to without feedback (0-30 s: 19.6%; 30-60 s: 33.1%; 60-90 s: 44.5%; 90-120 s: 32.7%) and no significant deteriorations over time were found within the groups. In the feedback group a significant improvement was found in the proportion of delivered compressions below target depth when the subsequent intervals were compared to the first 30 seconds (0-30 s: 3.9%; 30-60 s: 0.0%; 60-90 s: 0.0%; 90-120 s: 0.0%). Significant differences were not found in secondary outcome and in other performance variables between the groups and over time</p> <p>Conclusions</p> <p>Quality of CPR was maintained during 2 minutes of continuous compressions regardless of feedback in a group of trained rescuers.</p

Ein dimensionsunabhängiges topologisches Modell auf der Basis von Simplexen

Die geometrische Modellierung hat in den Ingenieurwissenschaften eine große Bedeutung erlangt. Die Visualisierung von zwei- oder dreidimensionalen Problemstellungen ist aus heutigen Anwendungen nicht mehr wegzudenken. Zunehmend rücken Aufgabenstellungen aus dem Bereich der geometrischen Modellierung in den Vordergrund, die über die etablierten Dimensionen 1-3 hinausgehen und die nicht mehr rein geometrischer Natur sind. Hierzu zählen Aufgabenstellungen aus den Bereichen numerische Simulation, Parameteridentifikation und Strukturanalyse. Auf diese nicht-geometrischen Aufgabenstellungen sollen geometrische Verfahren, wie z.B. Triangulation, konvexe Hülle, geometrischer Schnitt und Interpolation angewendet werden. Hierzu werden diese Algorithmen, die alle auf der klassischen Geometrie des euklidischen Raumes beruhen, auf ihre Übertragbarkeit hin analysiert und überarbeitet. Am Beispiel einer Parameteridentifikation wird eine systematische Vorgehensweise vorgestellt, die es ermöglicht, trotz weniger Versuchsrechnungen den Bereich der in Frage kommenden Parameter umfassend zu beschreiben. Dies ermöglicht ein besseres Verständnis der Zusammenhänge der Parameter untereinander. Häufig existieren mehr als eine Parameterkombination, so daß diese eine Isolinie formen, die ihrerseits unendlich viele Lösungen des gestellten Problemes im Untersuchungsgebiet beschreibt

Erosion Remineralization Efficacy of Gel-to-Foam Fluoride Toothpastes in situ: A Randomized Clinical Trial

This single-center, randomized, placebo-controlled, four-treatment, four-period crossover study compared the enamel remineralization effects of low- and medium-abrasivity gel-to-foam toothpastes and a reference toothpaste (all 1,450 ppm fluoride as NaF) versus placebo toothpaste (0 ppm fluoride) using a short-term in situ erosion model. Subjects (n = 56) wearing a palatal appliance holding acid-softened bovine enamel specimens brushed their teeth with the test toothpastes. Thereafter, the specimens were removed for analysis of percent surface microhardness recovery (%SMHR) and percent relative erosion resistance (%RER) at 2, 4, and 8 h. Both low- and medium-abrasivity gel-to-foam fluoride toothpastes and the reference toothpaste provided significantly greater %SMHR than placebo at all assessment time points (all p < 0.05). No statistically significant difference of %SMHR was observed between the fluoride treatment groups at any time point. Similarly, all fluoride products provided significantly superior %RER versus placebo (all p < 0.0001), whereas no significant difference of this parameter was noted between the fluoride treatment groups. Increasing numerical improvements of %SMHR and %RER were observed in all four treatment groups over time (2, 4, and 8 h). The present in situ model is a sensitive tool to investigate intrinsic and fluoride-enhanced rehardening of eroded enamel. All three fluoride toothpastes were more efficacious than placebo, and there were no safety concerns following single dosing in this short-term in situ model

Reply to Ali & Aitchison's comment on 'Restoration of Cenozoic deformation in Asia, and the size of Greater India'

International audienceNo abstrac

Highly accelerated simulations of glassy dynamics using GPUs: caveats on limited floating-point precision

Modern graphics processing units (GPUs) provide impressive computing resources, which can be accessed conveniently through the CUDA programming interface. We describe how GPUs can be used to considerably speed up molecular dynamics (MD) simulations for system sizes ranging up to about 1 million particles. Particular emphasis is put on the numerical long-time stability in terms of energy and momentum conservation, and caveats on limited floating-point precision are issued. Strict energy conservation over 10^8 MD steps is obtained by double-single emulation of the floating-point arithmetic in accuracy-critical parts of the algorithm. For the slow dynamics of a supercooled binary Lennard-Jones mixture, we demonstrate that the use of single-floating point precision may result in quantitatively and even physically wrong results. For simulations of a Lennard-Jones fluid, the described implementation shows speedup factors of up to 80 compared to a serial implementation for the CPU, and a single GPU was found to compare with a parallelised MD simulation using 64 distributed cores.Comment: 12 pages, 7 figures, to appear in Comp. Phys. Comm., HALMD package licensed under the GPL, see http://research.colberg.org/projects/halm

Abnormal vital signs are strong predictors for intensive care unit admission and in-hospital mortality in adults triaged in the emergency department - a prospective cohort study

<p>Abstract</p> <p>Background</p> <p>Assessment and treatment of the acutely ill patient have improved by introducing systematic assessment and accelerated protocols for specific patient groups. Triage systems are widely used, but few studies have investigated the ability of the triage systems in predicting outcome in the unselected acute population. The aim of this study was to quantify the association between the main component of the Hillerød Acute Process Triage (HAPT) system and the outcome measures; Admission to Intensive Care Unit (ICU) and in-hospital mortality, and to identify the vital signs, scored and categorized at admission, that are most strongly associated with the outcome measures.</p> <p>Methods</p> <p>The HAPT system is a minor modification of the Swedish Adaptive Process Triage (ADAPT) and ranks patients into five level colour-coded triage categories. Each patient is assigned a triage category for the two main descriptors; vital signs, T_vitals, and presenting complaint, T_complaint. The more urgent of the two determines the final triage category, T_final. We retrieved 6279 unique adult patients admitted through the Emergency Department (ED) from the Acute Admission Database. We performed regression analysis to evaluate the association between the covariates and the outcome measures.</p> <p>Results</p> <p>The covariates, T_vitals, T_complaintand T_finalwere all significantly associated with ICU admission and in-hospital mortality, the odds increasing with the urgency of the triage category. The vital signs best predicting in-hospital mortality were saturation of peripheral oxygen (SpO₂), respiratory rate (RR), systolic blood pressure (BP) and Glasgow Coma Score (GCS). Not only the type, but also the number of abnormal vital signs, were predictive for adverse outcome. The presenting complaints associated with the highest in-hospital mortality were 'dyspnoea' (11.5%) and 'altered level of consciousness' (10.6%). More than half of the patients had a T_complaintmore urgent than T_vitals, the opposite was true in just 6% of the patients.</p> <p>Conclusion</p> <p>The HAPT system is valid in terms of predicting in-hospital mortality and ICU admission in the adult acute population. Abnormal vital signs are strongly associated with adverse outcome, while including the presenting complaint in the triage model may result in over-triage.</p