The spatial distribution patterns of condensed phase post-blast explosive residues formed during detonation

The continued usage of explosive devices, as well as the ever growing threat of ‘dirty’ bombs necessitates a comprehensive understanding of particle dispersal during detonation events in order to develop effectual methods for targeting explosive and/or additive remediation efforts. Herein, the distribution of explosive analytes from controlled detonations of aluminised ammonium nitrate and an RDX-based explosive composition were established by systematically sampling sites positioned around each firing. This is the first experimental study to produce evidence that the post-blast residue mass can distribute according to an approximate inverse-square law model, while also demonstrating for the first time that distribution trends can vary depending on individual analytes. Furthermore, by incorporating blast-wave overpressure measurements, high-speed imaging for fireball volume recordings, and monitoring of environmental conditions, it was determined that the principle factor affecting all analyte dispersals was the wind direction, with other factors affecting specific analytes to varying degrees. The dispersal mechanism for explosive residue is primarily the smoke cloud, a finding which in itself has wider impacts on the environment and fundamental detonation theory

Morphological variations of explosive residue particles and implications for understanding detonation mechanisms

The possibility of recovering undetonated explosive residues following detonation events is well-known; however, the morphology and chemical identity of these condensed phase postblast particles remains undetermined. An understanding of the postblast explosive particle morphology would provide vital information during forensic examinations, allowing rapid initial indication of the explosive material to be microscopically determined prior to any chemical analyses and thereby saving time and resources at the crucial stage of an investigation. In this study, condensed phase particles collected from around the detonations of aluminized ammonium nitrate and RDX-based explosive charges were collected in a novel manner utilizing SEM stubs. By incorporating the use of a focused ion beam during analysis, for the first time it is possible to determine that such particles have characteristic shapes, sizes, and internal structures depending on the explosive and the distance from the detonation at which the particles are recovered. Spheroidal particles (10–210 μm) with microsurface features recovered following inorganic charge detonations were dissimilar to the irregularly shaped particles (5–100 μm) recovered following organic charge firings. Confirmatory analysis to conclude that the particles were indeed explosive included HPLC-MS, Raman spectroscopy, and mega-electron volt–secondary ionization mass spectrometry. These results may impact not only forensic investigations but also the theoretical constructs that govern detonation theory by indicating the potential mechanisms by which these particles survive and how they vary between the different explosive types.EPSRC Grant EP/G037264/

A magnetically collimated jet from an evolved star

Planetary nebulae often have asymmetric shapes, which could arise due to collimated jets from evolved stars before evolution to the planetary nebula phase. The source of jet collimation in these stars is unknown. Magnetic fields are thought to collimate outflows that are observed in many other astrophysical sources, such as active galactic nuclei and proto-stars, although hitherto there are no direct observations of both the magnetic field direction and strength in any collimated jet. Theoretical models have shown that magnetic fields could also be the dominant source of collimation of jet in evolved stars. Here we report measurements of the polarization of water vapour masers that trace the precessing jet emanating from the asymptotic giant branch star W43A at 2.6 kpc from the Sun, which is undergoing rapid evolution into a planetary nebula. The masers occur in two clusters at opposing tips of the jets, ~1,000 AU from the star. We find direct evidence that the magnetic field is collimating the jet.Comment: Published in Nature 440 (March 2nd 2006). High-res figures can be found at http://www.jb.man.ac.uk/~wouter/papers/w43a/w43a.htm

The malaria parasite egress protease SUB1 is a calcium-dependent redox switch subtilisin.

Malaria is caused by a protozoan parasite that replicates within an intraerythrocytic parasitophorous vacuole. Release (egress) of malaria merozoites from the host erythrocyte is a highly regulated and calcium-dependent event that is critical for disease progression. Minutes before egress, an essential parasite serine protease called SUB1 is discharged into the parasitophorous vacuole, where it proteolytically processes a subset of parasite proteins that play indispensable roles in egress and invasion. Here we report the first crystallographic structure of Plasmodium falciparum SUB1 at 2.25 Å, in complex with its cognate prodomain. The structure highlights the basis of the calcium dependence of SUB1, as well as its unusual requirement for interactions with substrate residues on both prime and non-prime sides of the scissile bond. Importantly, the structure also reveals the presence of a solvent-exposed redox-sensitive disulphide bridge, unique among the subtilisin family, that likely acts as a regulator of protease activity in the parasite

Prevalence of Neuroradiological Abnormalities in First-Episode Psychosis: A Systematic Review and Meta-analysis

IMPORTANCE: Individuals presenting with first-episode psychosis (FEP) may have a secondary ("organic") etiology to their symptoms that can be identified using neuroimaging. Because failure to detect such cases at an early stage can have serious clinical consequences, it has been suggested that brain magnetic resonance imaging (MRI) should be mandatory for all patients presenting with FEP. However, this remains a controversial issue, partly because the prevalence of clinically relevant MRI abnormalities in this group is unclear. OBJECTIVE: To derive a meta-analytic estimate of the prevalence of clinically relevant neuroradiological abnormalities in FEP. DATA SOURCES: Electronic databases Ovid, MEDLINE, PubMed, Embase, PsychINFO, and Global Health were searched up to July 2021. References and citations of included articles and review articles were also searched. STUDY SELECTION: Magnetic resonance imaging studies of patients with FEP were included if they reported the frequency of intracranial radiological abnormalities. DATA EXTRACTION AND SYNTHESIS: Independent extraction was undertaken by 3 researchers and a random-effects meta-analysis of pooled proportions was calculated. Moderators were tested using subgroup and meta-regression analyses. Heterogeneity was evaluated using the I2 index. The robustness of results was evaluated using sensitivity analyses. Publication bias was assessed using funnel plots and Egger tests. MAIN OUTCOMES AND MEASURES: Proportion of patients with a clinically relevant radiological abnormality (defined as a change in clinical management or diagnosis); number of patients needed to scan to detect 1 such abnormality (number needed to assess [NNA]). RESULTS: Twelve independent studies (13 samples) comprising 1613 patients with FEP were included. Of these patients, 26.4% (95% CI, 16.3%-37.9%; NNA of 4) had an intracranial radiological abnormality, and 5.9% (95% CI, 3.2%-9.0%) had a clinically relevant abnormality, yielding an NNA of 18. There were high degrees of heterogeneity among the studies for these outcomes, 95% to 73%, respectively. The most common type of clinically relevant finding was white matter abnormalities, with a prevalence of 0.9% (95% CI, 0%-2.8%), followed by cysts, with a prevalence of 0.5% (95% CI, 0%-1.4%). CONCLUSIONS AND RELEVANCE: This systematic review and meta-analysis found that 5.9% of patients presenting with a first episode of psychosis had a clinically relevant finding on MRI. Because the consequences of not detecting these abnormalities can be serious, these findings support the use of MRI as part of the initial clinical assessment of all patients with FEP

Evaluation of the i3 Scale-Up of Reading Recovery | Year Two Report, 2012-13

Reading Recovery is a short-term early intervention designed to help the lowest-achieving readers in first grade reach average levels of classroom performance in literacy. Students identified to receive Reading Recovery meet individually with a specially trained Reading Recovery teacher every school day for 30-minute lessons over a period of 12 to 20 weeks. The purpose of these lessons is to support rapid acceleration of each child’s literacy learning. In 2010, The Ohio State University received a Scaling Up What Works grant from the U.S. Department of Education Investing in Innovation (i3) Fund to expand the use of Reading Recovery across the country. The award was intended to fund the training of 3,675 new Reading Recovery teachers in U.S. schools, thereby expanding service to an additional 88,200 students. The Consortium for Policy Research in Education (CPRE) was contracted to conduct an independent evaluation of the i3 scale-up of Reading Recovery over the course of five years. The evaluation includes parallel rigorous experimental and quasi-experimental designs for estimating program impacts, coupled with a large-scale mixed-methods study of program implementation. This report presents the findings of the second year of the evaluation. The primary goals of this evaluation are: a) to provide experimental evidence of the impacts of Reading Recovery on student learning under this scale-up effort ; b) to assess the success of the scale-up in meeting the i3 grant’s expansion goals; and c) to document the implementation of the scale-up and fidelity to program standards. This document is the second in a series of three reports based on our external evaluation of the Reading Recovery i3 Scale-Up. This report presents results from the impact and implementation studies conducted over the 2012-2013 school year—the third year of the scale-up effort and the second full year of the evaluation. In order to estimate the impacts of the program, a sample of first graders who had been selected to receive Reading Recovery were randomly assigned to a treatment group that received Reading Recovery immediately, or to a control group that did not receive Reading Recovery until the treatment group had exited the intervention. The reading achievement of students in this sample was assessed using a standardized assessment of reading achievement—the Iowa Tests of Basic Skills (ITBS). The data for the implementation study include extensive interviews and surveys with Reading Recovery teachers, teacher leaders, site coordinators, University Training Center directors, members of the i3 project leadership team at The Ohio State University, and principals and first-grade teachers in schools involved in the scale-up. Case studies were also conducted in nine i3 scale-up schools to observe how Reading Recovery operates in different contexts

Turbulence in Global Simulations of Magnetized Thin Accretion Disks

We use a global magnetohydrodynamic simulation of a geometrically thin accretion disk to investigate the locality and detailed structure of turbulence driven by the magnetorotational instability (MRI). The model disk has an aspect ratio $H / R \simeq 0.07$, and is computed using a higher-order Godunov MHD scheme with accurate fluxes. We focus the analysis on late times after the system has lost direct memory of its initial magnetic flux state. The disk enters a saturated turbulent state in which the fastest growing modes of the MRI are well-resolved, with a relatively high efficiency of angular momentum transport $> \approx 2.5 \times 10^{-2}$. The accretion stress peaks at the disk midplane, above and below which exists a moderately magnetized corona with patches of superthermal field. By analyzing the spatial and temporal correlations of the turbulent fields, we find that the spatial structure of the magnetic and kinetic energy is moderately well-localized (with correlation lengths along the major axis of $2.5H$ and $1.5H$ respectively), and generally consistent with that expected from homogenous incompressible turbulence. The density field, conversely, exhibits both a longer correlation length and a long correlation time, results which we ascribe to the importance of spiral density waves within the flow. Consistent with prior results, we show that the mean local stress displays a well-defined correlation with the local vertical flux, and that this relation is apparently causal (in the sense of the flux stimulating the stress) during portions of a global dynamo cycle. We argue that the observed flux-stress relation supports dynamo models in which the structure of coronal magnetic fields plays a central role in determining the dynamics of thin-disk accretion.Comment: 24 pages and 25 figures. MNRAS in press. Version with high resolution figures available from http://jila.colorado.edu/~krb3u/Thin_Disk/thin_disk_turbulence.pd

‘On the outside I’m smiling but inside I’m crying’: communication successes and challenges for undergraduate academic writing

Student difficulties with the transition to writing in higher education are well documented whether from a ‘study skills’, an ‘academic socialisation’ or an ‘academic literacies’ perspective. In order to more closely examine the challenges faced by students from widening participation backgrounds and diverse routes into undergraduate study, this project focuses on first-year undergraduate experiences of developing academic literacies on an Education Studies programme at one university in England. It highlights the impact of different support and guidance within and beyond their degree programme where attempts to embed academic literacy development are part of subject modules. The paper reports the findings generated using a mixed methods interpretive approach. Questionnaires were collected at the beginning (n = 48) and end of the students’ first year (n = 44), and interviews and visual data collection methods (n =19) were used at the mid-point of the academic year. Key findings highlight students’ expectations of achievement on entry to university and the influence of the emotional journey of students as they begin to make progress as academic writers. Identifying, selecting and applying academic reading were an enduring concern whilst some students struggled with the digital literacy implicit in undergraduate work. Importantly, some strategies developed to support student transition to academic writing in higher education may have unintended consequences as they progress through the first year

Phase 1 Study of Two Merozoite Surface Protein 1 (MSP1(42)) Vaccines for Plasmodium falciparum Malaria

OBJECTIVES: To assess the safety and immunogenicity of two vaccines, MSP1(42)-FVO/Alhydrogel and MSP1(42)-3D7/Alhydrogel, targeting blood-stage Plasmodium falciparum parasites. DESIGN: A Phase 1 open-label, dose-escalating study. SETTING: Quintiles Phase 1 Services, Lenexa, Kansas between July 2004 and November 2005. PARTICIPANTS: Sixty healthy malaria-naïve volunteers 18–48 y of age. INTERVENTIONS: The C-terminal 42-kDa region of merozoite surface protein 1 (MSP1(42)) corresponding to the two allelic forms present in FVO and 3D7 P. falciparum lines were expressed in Escherichia coli, refolded, purified, and formulated on Alhydrogel (aluminum hydroxide). For each vaccine, volunteers in each of three dose cohorts (5, 20, and 80 μg) were vaccinated at 0, 28, and 180 d. Volunteers were followed for 1 y. OUTCOME MEASURES: The safety of MSP1(42)-FVO/Alhydrogel and MSP1(42)-3D7/Alhydrogel was assessed. The antibody response to each vaccine was measured by reactivity to homologous and heterologous MSP1(42), MSP1(19), and MSP1(33) recombinant proteins and recognition of FVO and 3D7 parasites. RESULTS: Anti-MSP1(42) antibodies were detected by ELISA in 20/27 (74%) and 22/27 (81%) volunteers receiving three vaccinations of MSP1(42)-FVO/Alhydrogel or MSP1(42)-3D7/Alhydrogel, respectively. Regardless of the vaccine, the antibodies were cross-reactive to both MSP1(42)-FVO and MSP1(42)-3D7 proteins. The majority of the antibody response targeted the C-terminal 19-kDa domain of MSP1(42), although low-level antibodies to the N-terminal 33-kDa domain of MSP1(42) were also detected. Immunofluorescence microscopy of sera from the volunteers demonstrated reactivity with both FVO and 3D7 P. falciparum schizonts and free merozoites. Minimal in vitro growth inhibition of FVO or 3D7 parasites by purified IgG from the sera of the vaccinees was observed. CONCLUSIONS: The MSP1(42)/Alhydrogel vaccines were safe and well tolerated but not sufficiently immunogenic to generate a biologic effect in vitro. Addition of immunostimulants to the Alhydrogel formulation to elicit higher vaccine-induced responses in humans may be required for an effective vaccine

Long-Term Outcomes After Transcatheter Aortic Valve Implantation in High-Risk Patients With Severe Aortic Stenosis The U.K. TAVI (United Kingdom Transcatheter Aortic Valve Implantation) Registry

ObjectivesThe objective was to define the characteristics of a real-world patient population treated with transcatheter aortic valve implantation (TAVI), regardless of technology or access route, and to evaluate their clinical outcome over the mid to long term.BackgroundAlthough a substantial body of data exists in relation to early clinical outcomes after TAVI, there are few data on outcomes beyond 1 year in any notable number of patients.MethodsThe U.K. TAVI (United Kingdom Transcatheter Aortic Valve Implantation) Registry was established to report outcomes of all TAVI procedures performed within the United Kingdom. Data were collected prospectively on 870 patients undergoing 877 TAVI procedures up until December 31, 2009. Mortality tracking was achieved in 100% of patients with mortality status reported as of December 2010.ResultsSurvival at 30 days was 92.9%, and it was 78.6% and 73.7% at 1 year and 2 years, respectively. There was a marked attrition in survival between 30 days and 1 year. In a univariate model, survival was significantly adversely affected by renal dysfunction, the presence of coronary artery disease, and a nontransfemoral approach; whereas left ventricular function (ejection fraction <30%), the presence of moderate/severe aortic regurgitation, and chronic obstructive pulmonary disease remained the only independent predictors of mortality in the multivariate model.ConclusionsMidterm to long-term survival after TAVI was encouraging in this high-risk patient population, although a substantial proportion of patients died within the first year