10,432 research outputs found
Blast mines: physics, injury mechanisms and vehicle protection.
Since World War II, more vehicles have been lost to land mines than all other threats combined. Anti-vehicular (AV) mines are capable of disabling a heavy vehicle, or completely destroying a lighter vehicle. The most common form of AV mine is the blast mine, which uses a large amount of explosive to directly damage the target. In a conventional military setting, landmines are used as a defensive force-multiplier and to restrict the movements of the opposing force. They are relatively cheap to purchase and easy to acquire, hence landmines are also potent weapons in the insurgents armamentarium. The stand-offnature of its design has allowed insurgents to cause significant injuries to security forces in current conflicts with little personal risk. As a result, AV mines and improvised explosive devices (IEDs) have become the most common cause of death and injury to Coalition and local security forces operating in Iraq and Afghanistan. Detonation of an AV mine causes an explosive, exothermic reaction which results in the formation of a shockwave followed by a rapid expansion of gases. The shockwave is mainly reflected by the soillair interface and fractures the soil cap overthe mine. The detonation products then vent through the voids in the soil, resulting in a hollow inverse cone which consists of the detonation gases surrounded by the soil ejecta. It is the combination of the detonation products and soil ejecta that interact with the target vehicle and cause injury to the vehicle occupants. A number of different strategies are required to mitigate the blast effects of an explosion. Primary blast effects can be reduced by increasing the standoff distance between the seat of the explosion and the crew compartment. Enhancement of armour on the base of the vehicle, as well as improvements in personal protection can prevent penetration of fragments. Mitigating tertiary effects can be achieved by altering the vehicle geometry and structure, increasing vehicle mass, as well as developing new strategies to reduce the transfer of the impulse through the vehicle to the occupants. Protection from thermal injury can be provided by incorporating fire resistant materials into the vehicle and in personal clothing. The challenge for the vehicle designer is the incorporation of these protective measures within an operationally effective platform.Published versio
Developing an intervention to improve reading comprehension for children and young people with autism spectrum disorders
Aim: A substantial proportion of children and young people with autism demonstrate accurate word reading
but struggle to understand the content of what they are reading. There is an urgent need for further research
in this area to enable educational professionals to implement evidence-based reading interventions. / Method/Rationale: This study analyses the effectiveness of an intervention designed to improve the reading
comprehension of young people with autism and reading comprehension diffculties (mean age 13 years,
6 months). The intervention was delivered twice a week over a period of six weeks. / Findings: The results indicate that the intervention group (N=15) demonstrated a signifcantly greater
increase in their reading comprehension than a âtreatment as usualâ control group (N=14), showing an
average of three yearsâ improvement in their reading comprehension. Semi-structured interviews with
participants indicated that many demonstrated a shift in their approach to reading, with a greater focus on
comprehension and an awareness of transferring the skills they had learnt to other areas of the curriculum.
Participants also identifed that the intervention supported their speaking and listening skills. / Limitations: The small size of the sample in this study limits the generalisation of the fndings.
The robustness of the fndings would be increased by including long-term outcome measures. / Conclusions: These fndings present important implications for professionals working with young people and
suggest that school-based reading interventions may be effective at developing the reading comprehension of
individuals with autism
The road to elimination of hepatitis C: analysis of cures versus new infections in 91 countries.
BACKGROUND: Hepatitis C (HCV) can only be eradicated if annual rates of cure (SVR) are consistently and significantly higher than new HCV infections, across many countries. In 2016, the WHO called for a 90% reduction in new HCV infection by 2030. Direct-acting antivirals (DAA) can cure the majority of those treated, at around 90% in most populations, at potentially very low prices. We compared the net annual change in epidemic size across 91 countries using data on SVR, new HCV infections, and deaths. In a further 109 countries, we projected this figure using regional averages of epidemic size. METHODS: Epidemiological data for 2016 were extracted from national reports, publications and the Polaris Observatory. There were 91/210 countries with data on SVR, HCV-related deaths and new infections available for analysis; 109 countries had net change in epidemic size projected from the regional prevalence of HCV, extrapolated to their population size. 'Net cure' was defined as the number of people with SVR, minus new HCV infections, plus HCV-related deaths in 2016. RESULTS: For the 91 countries analysed, there were 57.3 million people with chronic HCV infection in 2016. In the remaining 109 countries, the projected epidemic size was 12.2 million, giving a global epidemic size of 69.6 million. Across the 91 countries, there was a fall from 57.3 to 56.9 million people in 2017, a 0.7% reduction. The projected global net change was from 69.6 to 69.3 million, a 0.4% reduction. Ten countries had at least five times more people reaching SVR than new HCV infections, including Egypt and USA. In 47/91 countries, there were more HCV infections than SVR in 2016. CONCLUSION: Very few countries are on target to achieve elimination of HCV as a public health problem by 2030. While the North American, North African/Middle East and Western European regions have shown small declines in prevalence, the epidemic is growing in sub-Saharan Africa and Eastern Europe. Far higher rates of DAA treatment are required for worldwide elimination of HCV
The latitudinal diversity gradient of tetrapods across the Permo-Triassic mass extinction and recovery interval
The decline in species richness from the equator to the poles is referred to as the latitudinal diversity gradient (LDG). Higher equatorial diversity has been recognized for over 200 years, but the consistency of this pattern in deep time remains uncertain. Examination of spatial biodiversity patterns in the past across different global climate regimes and continental configurations can reveal how LDGs have varied over Earth history and potentially differentiate between suggested causal mechanisms. The Late PermianâMiddle Triassic represents an ideal time interval for study, because it is characterized by large-scale volcanic episodes, extreme greenhouse temperatures and the most severe mass extinction event in Earth history. We examined terrestrial and marine tetrapod spatial biodiversity patterns using a database of global tetrapod occurrences. Terrestrial tetrapods exhibit a bimodal richness distribution throughout the Late PermianâMiddle Triassic, with peaks in the northern low latitudes and southern mid-latitudes around 20â40° N and 60° S, respectively. Marine reptile fossils are known almost exclusively from the Northern Hemisphere in the Early and Middle Triassic, with highest diversity around 20° N. Reconstructed terrestrial LDGs contrast strongly with the generally unimodal gradients of today, potentially reflecting high global temperatures and prevailing Pangaean super-monsoonal climate system during the Permo-Triassic
The Sex and Race Specific Relationship between Anthropometry and Body Fat Composition Determined from Computed Tomography: Evidence from the Multi-Ethnic Study of Atherosclerosis.
BackgroundFew studies have investigated the relationship of anthropometric measurements with computed tomography (CT) body fat composition, and even fewer determined if these relationships differ by sex and race.MethodsCT scans from 1,851 participants in the population based Multi-Ethnic Study of Atherosclerosis were assessed for visceral and subcutaneous fat areas by semi-automated segmentation of body compartments. Regression models were used to investigate relationships for anthropometry with visceral and subcutaneous fat separately by sex and race/ethnicity.ResultsParticipants were 50% female, 41% Caucasian, 13% Asian, 21% African American, and 25% Hispanic. For visceral fat, the positive relationship with weight (p = 0.028), waist circumference (p<0.001), waist to hip ratio (p<0.001), and waist to height ratio (p = 0.05) differed by sex, with a steeper slope for men. That is, across the range of these anthropometric measures the rise in visceral fat is faster for men than for women. Additionally, there were differences by race/ethnicity in the relationship with height (p<0.001), weight (p<0.001), waist circumference (p<0.001), hip circumference (p = 0.006), and waist to hip ratio (p = 0.001) with the Hispanic group having shallower slopes. For subcutaneous fat, interaction by sex was found for all anthropometric indices at p<0.05, but not for race/ethnicity.ConclusionThe relationship between anthropometry and underlying adiposity differs by sex and race/ethnicity. When anthropometry is used as a proxy for visceral fat in research, sex-specific models should be used
Unique Data Sets and Bespoke Laboratory Videos: Teaching and Assessing of Experimental Methods and Data Analysis in a Pandemic
This is the final version. Available on open access from the American Chemical Society via the DOI in this recordThe COVID-19 pandemic necessitated the move to online teaching and assessment. This has created challenges in teaching laboratory skills and producing assessments that are robust and fair. Our solution was to use bespoke laboratory videos to provide laboratory training and to generate unique data sets for each student in coursework and exams. For assessments, R was used to produce student data packs comprising data and images, and associated staff answer files with plotted data and worked answers. In the new open-book online environment, this approach enabled us to create assessments that were the studentsâ own work with no evidence of student collusion. We observed no difference in student performance for the coursework or exam: The mean and median marks for the course remained the same as in previous years
A Murder Mystery Gamification Session to Consolidate Analytical Biochemical Techniques Learning
This is the final version. Available on open access from the American Chemical Society via the DOI in this recordData Availability:
A video explaining the scripts and giving an example of use can be found at (https://youtu.be/zfCNjB2KYDQ). R scripts are also available from GitHub (https://github.com/njharmer/Biochem-murder-mystery). R scripts can be run through a web browser at CodeOcean (https://codeocean.com/capsule/8095683/tree/v2). Users should read the packet metadata before running.Gamification has a strong track record of improving student engagement and learning in the chemical sciences. Meta-analyses of different approaches to gamification have highlighted that providing a game fiction, encouraging students to work in teams, and breaking games into smaller âquestsâ are particularly effective. Here, we aimed to increase studentsâ engagement and learning with four analytical biochemistry techniques (high-performance liquid chromatography, sodium dodecyl sulfate polyacrylamide gel electrophoresis, Western blot, and mass spectrometry) by creating a game that required them to use every method to solve a âmurder mysteryâ. Our game was based on the popular games âMafiaâ and âAmong Usâ and introduced an original game fiction relevant to our setting. Students attending the formative gamified session gave highly positive feedback. They indicated that they enjoyed the session and increased confidence in the methods involved. Free text comments praised many of the elements deliberately introduced into the game. To our surprise, the main criticism was that the session was not challenging enough. We developed a revised session that required students to undertake more detailed data interpretation, which students reported gave the expected increase in difficulty. All materials and code for running our session and generating new mysteries with original data are available online
Tailored education for older patients to facilitate engagement in falls prevention strategies after hospital dischargeâA pilot randomized controlled trial
Background
The aims of the study were to evaluate the effect of providing tailored falls prevention education in hospital on: i) engagement in targeted falls prevention behaviors in the month after discharge: ii) patientsâ self-perceived risk and knowledge about falls and falls prevention strategies after receiving the education. Methods
A pilot randomized controlled trial (n = 50): baseline and outcome assessments conducted by blinded researchers. Participants: hospital inpatients 60 years or older, discharged to the community. Participants were randomized into two groups. The intervention was a tailored education package consisting of multimedia falls prevention information with trained health professional follow-up, delivered in addition to usual care. Outcome measures were engagement in falls prevention behaviors in the month after discharge measured at one month after discharge with a structured survey, and participantsâ knowledge, confidence and motivation levels before and after receiving the education. The feasibility of providing the intervention was examined and falls outcomes (falls, fall-related injuries) were also collected. Results
Forty-eight patients (98%) provided follow-up data. The complete package was provided to 21 (84%) intervention group participants. Participants in the intervention group were significantly more likely to plan how to safely restart functional activities [Adjusted odds ratio 3.80, 95% CI (1.07, 13.52), p = 0.04] and more likely to complete other targeted behaviors such as completing their own home exercise program [Adjusted odds ratio 2.76, 95% CI (0.72, 10.50), p = 0.14] than the control group. The intervention group was significantly more knowledgeable, confident and motivated to engage in falls prevention strategies after receiving the education than the control group. There were 23 falls (n = 5 intervention; n = 18 control) and falls rates were 5.4/1000 patient days (intervention); 18.7/1000 patient days (control). Conclusion
This tailored education was received positively by older people, resulted in increased engagement in falls prevention strategies after discharge and is feasible to deliver to older hospital patients. Trial registration
The study was registered with the Australian New Zealand Clinical Trials Registry; ACTRN12611000963921 on 8th November 2011
A critical evaluation of the Oscillayers methods and datasets
Here we evaluate Oscillayers, a new method that aims to estimate palaeoclimates for the past 5.4 Myr, and discuss the associated theoretical and methodological issues. We show that the theoretical foundation of Oscillayers is inherently limited, because the method cannot incorporate spatioâtemporal variation and different forcing mechanisms into climate reconstructions. In addition, several methodological weaknesses are clarified that entrench the palaeoclimatic reconstruction of Oscillayers to patterns of climate change observed between the Last Glacial Maximum and current climates. We test the utility of the Oscillayers method to produce palaeoclimatic reconstructions that are similar to general circulation model (GCM)âbased estimates. On average, only 55.6% of values in the mean annual temperature datasets across the Pliocene and Pleistocene were within ±3°C when compared with corresponding GCMâbased datasets. Furthermore, on average only 75.3% of values in the mean annual precipitation datasets across the Pliocene and Pleistocene were within ±200 mm of rainfall of the GCMâbased estimates. Our results demonstrate that the Oscillayers approach does not provide a robust approximation of palaeoclimatic conditions throughout the PlioâPleistocene. Thus, when these datasets are used for scientific analyses, the results should be interpreted with a full appreciation of their limitations, particularly for periods outside the last glacial cycle
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