High level sill and dyke intrusions initiated from rapidly buried mafic lava flows in scoria cones of Tongoa, Vanuatu (New Hebrides), South Pacific

Scoria cones are generally considered to grow rapidly in days to weeks or months. During their growth lava flows may be fed onto the cone surface from lava-lake breaches, or form by coalescence of spatter; such flows are preserved interbedded with scoria lapilli and ash beds. On Tongoa, an island of the Vanuatu volcanic arc in the South Pacific, a series of scoria cones developed during the Holocene, forming a widespread monogenetic volcanic field. Half sections of scoria cones along the coast expose complex interior architecture cone architectures. On the western side of Tongoa Island a scoria cone remnant with steeply crater-ward dipping beds of scoria ash and lapilli contains various dm-to-m thick lava flows, which are connected by irregular dikes cutting obliquely across the beds of the cone. The lava flows are coherent igneous bodies with well-developed flow top and basal breccias. The lavas interbedded with the cone-forming layers are part of a larger (up to 7 m thick) body that is connected to dykes and sills of irregular geometries that intrude the cone's pyroclastic layers. This 3D relationship suggests that the lava flows were buried quickly under the accumulating scoriaceous deposits. This allowed subsequent escape of magma from the fluid interiors of flows, with the magma then squeezed upward or laterally into the accumulating pyroclastic pile. Movement of the pile above the partly mobile lava, and potential destabilisation during intrusion into the pile of lava squeezed from the flows, may signal the onset of localised cone failures, and could be implicated in development of major cone breaches (e.g. Paricutin)

Compositional variation during monogenetic volcano growth and its implications for magma supply to continental volcanic fields

Individual volcanoes of continental monogenetic volcanic fields are generally presumed to erupt single magma batches during brief eruptions. Nevertheless, in two unrelated volcanic fields (the Waipiata volcanic field, New Zealand, and the Miocene-Pliocene volcanic field in western Hungary), we have identified pronounced and systematic compositional differences among products of individual volcanoes. We infer that this indicates a two-stage process of magma supply for these volcanoes. Each volcano records: (1) intrusion of a basanitic parent magma to lower- to mid-crustal levels and its subsequent fractionation to form a tephritic residual melt;, (2) subsequent transection of this reservoir by a second batch of basanitic melt, with tephrite rising to the surface at the head of the propagating basanite dyke. Eruption at the surface then yields initial tephrite, typically erupted as pyroclasts, followed by eruption and shallow intrusion of basanite from deeper in the dyke. By analogy with similar tephrite-basanite eruptions along rift zones of intraplate ocean-island volcanoes, we infer that fractionation to tephrite would have required decades to centuries. We conclude that the two studied continental monogenetic volcanic fields demonstrate a consistent history of early magmatic injections that fail to reach the surface, followed by capture and partial eruption of their evolved residues in the course of separate and significantly later injections of basanite that extend to the surface and erupt. This systematic behaviour probably reflects the difficulty of bringing small volumes of dense, primitive magma to the surface from mantle source regions. Ascent through continental crust is aided by the presence in the dyke head of buoyant tephrite captured during transection of the earlier-emplaced melt bodies

High energy and high power primary Li-CFx_x batteries enabled by the combined effects of the binder and the electrolyte

Several effective methods have been developed recently to demonstrate simultaneous high energy and high power density in Li - carbon fluoride (CF$_x$) batteries. These methods can achieve as high as 1000 Wh/kg energy density at 60-70 kW/kg power density (40-50 C rate) in coin cells and 750 Wh/kg energy density at 12.5 kW/kg power density (20 C rate) in pouch cells. This performance is made possible by ingenious nano-architecture design, controlled porosity, boron doping and electrolyte additives. In the present study, we show that a similarly great performance, 931 Wh/kg energy density at 59 kW/kg power density, can be achieved by using a polyacrylonitrile binder and a LiBF4 electrolyte in Li - graphite fluoride coin cells. We also demonstrate that the observed effect is the result of the right combination of the binder and the electrolyte. We propose that the mechanistic origin of the observed phenomena is an electro-catalytic effect by the polyacrylonitrile binder. While our proposed method has a competitive performance, it also offers a simple implementation and a scalable production of high energy and high power primary Li-CF$_x$ cells.Comment: 13 pages, 8 figures, 1 tabl

Investigating the Integration of Student Learning Resources in Preparation for the NCLEX-RN: Phase One of a Canadian Two-Phase Multi-Site Study

Evidence-informed education practices are critical in determining effective student preparatory learning resources for the NCLEX-RN examination. Standardized testing in nursing education programs has been demonstrated to increase students NCLEX-RN success. A widely researched assessment tool for predicting NCLEX-RN examination outcomes is the HESITM RN Exit Exams. The HESI Exit Exam (E2) was determined to be between 93.36% and 99.16% accurate in predicting NCLEX-RN success (N = 49,115) with samples derived from various nursing programs throughout the United States. Purpose: This two-phase, multi-site ex-post facto study was to investigate NCLEX-RN Student Preparatory Learning Resources within the Canadian context. Phase One, which is reported here, was to determine if there was a relationship between student HESITM RN Exit and Computer Adaptive Testing (CAT) Exam scores, student grade point average (GPA), and the time lag between graduation and writing the National Licensure exam, and student outcome on the NCLEX-RN exam. Procedure: New nursing graduates were emailed study information and asked to provide their consent for the use of their student data (GPA, HESITM Exit and CAT Exam scores) for research purposes and to request that they self-report (via a password protected secure email address created for this study) their NCLEX-RN Licensure exam date and result (pass/fail) of their first exam writing. Results: Among a convenience sample of 117 new nursing alumni (graduates of 2015) from three universities in Nova Scotia, we found statistically significant mean differences in HESITM RN Exit Exam Version 1, Version 2, and CAT scores among those students that were successful on the NCLEX-RN exam versus those students that were not successful on their first writing of the NCLEX-RN exam. There was an inverse statistically significant relationship between time lag and NCLEX-RN outcome indicating that the longer the time period from graduation to writing, the less likely that the student will be successful. We found no relationship between student GPA and NCLEX-RN outcome. Discussion: Phase One results of this study suggest that there are differences in HESITM RN Exit exam and CAT scores among those students who were successful on the first write of NCLEX-RN exam versus those students who were not successful.. Although HESITM exams are just one type of the many available nursing resources to assist students to prepare for writing the National Licensure examination, our findings are significant and warrant Canadian nurse educators’ attention. Résumé Les pratiques de formation fondées sur des résultats probants sont essentielles pour déterminer l’efficacité des ressources d’apprentissage préparatoires à l’examen NCLEX-RN offertes aux étudiantes. Il a été démontré que l’utilisation d’examens standardisés dans les programmes de formation en sciences infirmières augmente le taux de réussite des étudiants à l’examen NCLEX-RN. Un outil d’évaluation qui a été largement étudié et qui permet de prédire les résultats d’examen au NCLEX-RN est l’examen final HESIMD RN. Il a été déterminé que l’examen final HESI (E2) prédisait avec une précision se situant entre 93,36 % et 99,16 % le taux de réussite à l’examen NCLEX-RN (N = 49 115) dans des échantillons provenant de différents programmes de sciences infirmières aux États-Unis. Objectif : Cette étude multi-sites, en deux phases, réalisée a posteriori visait à examiner les ressources d’apprentissage préparatoires au NCLEX-RN offertes aux étudiantes dans le contexte canadien. La première phase, dont il est question dans cet article, était conçue pour déterminer s’il existait une relation entre les résultats d’examens finaux au HESIMD RN, les résultats au test adaptatif informatisé (TAI), la moyenne générale (MG) des étudiants, l’intervalle de temps entre l’obtention du diplôme et le passage de l’examen national d’autorisation à exercer, et les résultats à l’examen NCLEX-RN. Procédure : Les nouvelles diplômées en sciences infirmières recevaient un courriel fournissant des informations sur l’étude et sollicitant leur consentement pour l’utilisation de données de leur dossier d’étudiante (leur MG, leur résultat à l’examen final HESIMD et leur résultat au TAI) à des fins de recherche. Ce message leur demandait également de déclarer (par l’entremise d’une adresse courriel sécurisée protégée par mot de passe et créée pour l’étude) la date et le résultat (réussite/échec) de leur premier examen d’autorisation à exercer NCLEX-RN. Résultats : Dans l’échantillon de convenance de 117 nouvelles diplômées en sciences infirmières (diplômées de 2015) de trois universités en Nouvelle-Écosse, nous avons découvert des différences de moyennes statistiquement significatives entre les étudiantes qui ont réussi à l’examen NCLEX-RN et celles qui ne l’ont pas réussi à la première tentative, pour leurs résultats à l’examen final HESIMD RN, version 1 et version 2, et les résultats du TAI. . Une relation inverse statistiquement significative fut remarquée entre l’intervalle de temps avant de passer l’examen NCLEX-RN et le résultat à ’cet examen, ce qui indique que plus la période est longue entre l’obtention du diplôme et le passage de l’examen, moins il est probable que l’étudiante réussisse l’examen. Nous n’avons trouvé aucune relation entre la MG de l’étudiante et le résultat au NCLEX-RN. Discussion : Les résultats de la première phase de cette étude indiquent qu’il existe des différences quant aux résultats à l’examen final HESIMD RN et au TAI entre les étudiantes qui ont réussi l’examen NCLEX-RN la première fois et celles qui l’ont échoué. Bien que les examens HESIMD ne soient qu’un type de ressources parmi de nombreuses autres ressources disponibles en sciences infirmières pour aider les étudiantes à se préparer à l’examen national d’autorisation à exercer, nos résultats sont significatifs et méritent l’attention des infirmières formatrices canadiennes

Picoliter-volume inkjet printing into planar microdevice reservoirs for low-waste, high-capacity drug loading.

Oral delivery of therapeutics is the preferred route for systemic drug administration due to ease of access and improved patient compliance. However, many therapeutics suffer from low oral bioavailability due to low pH and enzymatic conditions, poor cellular permeability, and low residence time. Microfabrication techniques have been used to create planar, asymmetric microdevices for oral drug delivery to address these limitations. The geometry of these microdevices facilitates prolonged drug exposure with unidirectional release of drug toward gastrointestinal epithelium. While these devices have significantly enhanced drug permeability in vitro and in vivo, loading drug into the micron-scale reservoirs of the devices in a low-waste, high-capacity manner remains challenging. Here, we use picoliter-volume inkjet printing to load topotecan and insulin into planar microdevices efficiently. Following a simple surface functionalization step, drug solution can be spotted into the microdevice reservoir. We show that relatively high capacities of both topotecan and insulin can be loaded into microdevices in a rapid, automated process with little to no drug waste

A new sdO+dM binary with extreme eclipses and reflection effect

We report the discovery of a new totally-eclipsing binary (RA=06:40:29.11; Dec=+38:56:52.2; J=2000.0; Rmax=17.2 mag) with an sdO primary and a strongly irradiated red dwarf companion. It has an orbital period of Porb=0.187284394(11) d and an optical eclipse depth in excess of 5 magnitudes. We obtained two low-resolution classification spectra with GTC/OSIRIS and ten medium-resolution spectra with WHT/ISIS to constrain the properties of the binary members. The spectra are dominated by H Balmer and He II absorption lines from the sdO star, and phase-dependent emission lines from the irradiated companion. A combined spectroscopic and light curve analysis implies a hot subdwarf temperature of Teff(spec) = 55 000 +/- 3000K, surface gravity of log g(phot) = 6.2 +/- 0.04 (cgs) and a He abundance of log(nHe/nH) = -2.24 +/- 0.40. The hot sdO star irradiates the red-dwarf companion, heating its substellar point to about 22 500K. Surface parameters for the companion are difficult to constrain from the currently available data: the most remarkable features are the strong H Balmer and C II-III lines in emission. Radial velocity estimates are consistent with the sdO+dM classification. The photometric data do not show any indication of sdO pulsations with amplitudes greater than 7mmag, and Halpha-filter images do not provide evidence of the presence of a planetary nebula associated with the sdO star.Comment: 13 pages, 5 figures; accepted for publication in Ap

Reliability Assessment of Graphite Specimens under Multiaxial Stresses

An investigation was conducted to predict the failure strength response of IG-100 nuclear grade graphite exposed to multiaxial stresses. As part of this effort, a review of failure criteria accounting for the stochastic strength response is provided. The experimental work was performed in the early 1990s at the Oak Ridge National Laboratory (ORNL) on hollow graphite tubes under the action of axial tensile loading and internal pressurization. As part of the investigation, finite-element analysis (FEA) was performed and compared with results of FEA from the original ORNL report. The new analysis generally compared well with the original analysis, although some discrepancies in the location of peak stresses was noted. The Ceramics Analysis and Reliability Evaluation of Structures Life prediction code (CARES/Life) was used with the FEA results to predict the quadrants I (tensile-tensile) and quadrant IV (compression-tension) strength response of the graphite tubes for the principle of independent action (PIA), the Weibull normal stress averaging (NSA), and the Batdorf multiaxial failure theories. The CARES/Life reliability analysis showed that all three failure theories gave similar results in quadrant I but that in quadrant IV, the PIA and Weibull normal stress-averaging theories were not conservative, whereas the Batdorf theory was able to correlate well with experimental results. The conclusion of the study was that the Batdorf theory should generally be used to predict the reliability response of graphite and brittle materials in multiaxial loading situations