445 research outputs found
High spectral resolution ozone absorption cross-sections – Part 1: Measurements, data analysis and comparison with previous measurements around 293 K
In this paper we discuss the methodology of taking broadband relative and
absolute measurements of ozone cross-sections including uncertainty budget,
experimental set-ups, and methods for data analysis. We report on new ozone
absorption cross-section measurements in the solar spectral region using a
combination of Fourier transform and echelle spectrometers. The new
cross-sections cover the spectral range 213–1100 nm at a spectral
resolution of 0.02–0.06 nm in the UV–visible and 0.12–0.24 nm in the IR at
eleven temperatures from 193 to 293 K in steps of 10 K. The absolute
accuracy is better than three percent for most parts of the spectral region
and wavelength calibration accuracy is better than 0.005 nm.
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The new room temperature cross-section data are compared in detail with
previously available literature data. The temperature dependence of our
cross-sections is described in a companion paper (Serdyuchenko et al., 2014)
Leveraging machine learning to predict rail corrugation level from axle-box acceleration measurements on commercial vehicles
Rail corrugation is a prominent degradative problem in the health monitoring of railway systems. Monitoring process is dependent on use of a diagnostic trolley, which is expensive and needs the track to be out-of-service. Alternatively, in-service rail vehicles with Axle-Box Acceleration measurement systems installed, have shown success in detecting rail corrugation levels based on physical models, albeit with limitations. Extending this approach, we build a Machine Learning model, represented by a tuned Random Forest regressor, trained on collected accelerometer signals along with other offline and/or static features. We also propose a method to engineer acceleration-based features which nullifies the aggregated acceleration vibrations inherited from the other rail due to dynamically coupled vibrations between the left and right rails. The resulting model is able to recreate the moving RMS irregularity profile at bandwidth 100-300 mm, especially in highly corrugated sections, with an R-2 score of 0.97-0.98. The results show that the suggested data-driven approach outperforms a state-of-the-art model-based benchmark
Perspectives of frailty and frailty screening: Protocol for a collaborative knowledge translation approach and qualitative study of stakeholder understandings and experiences
Accompanying the unprecedented growth in the older adult population worldwide is an increase in the prevalence of frailty, an age-related clinical state of increased vulnerability to stressor events. This increased vulnerability results in lower social engagement and quality of life, increased dependency, and higher rates of morbidity, health service utilization and mortality. Early identification of frailty is necessary to guide implementation of interventions to prevent associated functional decline. Consensus is lacking on how to clinically recognize and manage frailty. It is unknown how healthcare providers and healthcare consumers understand and perceive frailty, whether or not they regard frailty as a public health concern; and information on the indirect and direct experiences of consumer and healthcare provider groups towards frailty are markedly limited.We will conduct a qualitative study of consumer, practice nurse, general practitioner, emergency department physician, and orthopedic surgeons' perspectives of frailty and frailty screening in metropolitan and non-metropolitan South Australia. We will use tailored combinations of semi-structured interviews and arts-based data collection methods depending on each stakeholder group, followed by inductive and iterative analysis of data using qualitative description.Using stakeholder driven approaches to understanding and addressing frailty and frailty screening in context is critical as the prevalence and burden of frailty is likely to increase worldwide. We will use the findings from the Perceptions of Frailty and Frailty Screening study to inform a context-driven identification, implementation and evaluation of a frailty-screening tool; drive awareness, knowledge, and skills development strategies across stakeholder groups; and guide future efforts to embed emerging knowledge about frailty and its management across diverse South Australian contexts using a collaborative knowledge translation approach. Study findings will help achieve a coordinated frailty and healthy ageing strategy with relevance to other jurisdictions in Australia and abroad, and application of the stakeholder driven approach will help illuminate how its applicability to other jurisdictions.Mandy M. Archibald, Rachel Ambagtsheer, Justin Beilby, Mellick J. Chehade, Tiffany K. Gill, Renuka Visvanathan, and Alison L. Kitso
Assessment of Damage to Nucleic Acids and Repair Machinery in Salmonella typhimurium Exposed to Chlorine
Water disinfection is usually evaluated using mandatory methods based on cell culturability. However, such methods do not consider the potential of cells to recover, which should also be kept as low as possible. In this paper, we hypothesized that a successful disinfection is achieved only when the applied chlorine leads to both intracellular nucleic acid damage and strong alterations of the DNA repair machinery. Monitoring the SOS system responsiveness with a umuC’-‘lacZ reporter fusion, we found that the expression of this important cellular machinery was altered after the beginning of membrane permeabilization but prior to the total decline of both the cell culturability and the nucleic acid integrity as revealed by Sybr-II staining. Rapid measurement of such nucleic acid alterations by fluorochrome-based staining could be used as an alternative method for assessing the effectiveness of disinfection with chlorine
Pneumopericardium, pneumomediastinum and air travel: A case report in a patient with Gardner syndrome
© 2020 The Author(s) Onboard aircraft medical emergencies are on the rise as commercial air traffic is increasing. However, thoracic injury secondary to air travel is extremely rare and, most reported injuries are cases of pneumothoraces. Spontaneous pneumomediastinum and pneumopericardium have been barely reported in the medical literature as a complication of air travel. We are reporting a case of spontaneous pneumopericardium and pneumomediastinum in a patient with Gardner\u27s Syndrome after a flight from Central America to New York City. The patient presented with chest discomfort. He was managed conservatively with oxygen therapy as he was hemodynamically stable throughout his stay in the hospital. A thorough work up in hospital including and esophagogram and a CT scan of the chest were none revealing of the cause. However, the patient was noted to have metastatic rectal cancer with lung involvement. The patient was discharged with instructions to avoid air travel
Long-term impact of maternal high-fat diet on offspring cardiac health: role of micro-RNA biogenesis.
Heart failure is a worldwide leading cause of death. Diet and obesity are particularly of high concern in heart disease etiology. Gravely, altered nutrition during developmental windows of vulnerability can have long-term impact on heart health; however, the underlying mechanisms are poorly understood. In the understanding of the initiation of chronic diseases related to developmental exposure to environmental challenges, deregulations in epigenetic mechanisms including micro-RNAs have been proposed as key events. In this context, we aimed at delineating the role of micro-RNAs in the programming of cardiac alterations induced by early developmental exposure to nutritional imbalance. To reach our aim, we developed a human relevant model of developmental exposure to nutritional imbalance by maternally exposing rat to high-fat diet during gestation and lactation. In this model, offspring exposed to maternal high-fat diet developed cardiac hypertrophy and increased extracellular matrix depot compared to those exposed to chow diet. Microarray approach performed on cardiac tissue allowed the identification of a micro-RNA subset which was down-regulated in high-fat diet-exposed animals and which were predicted to regulate transforming growth factor-beta (TGFβ)-mediated remodeling. As indicated by in vitro approaches and gene expression measurement in the heart of our animals, decrease in DiGeorge critical region 8 (DGCR8) expression, involved in micro-RNA biogenesis, seems to be a critical point in the alterations of the micro-RNA profile and the TGFβ-mediated remodeling induced by maternal exposure to high-fat diet. Finally, increasing DGCR8 activity and/or expression through hemin treatment in vitro revealed its potential in the rescue of the pro-fibrotic phenotype in cardiomyocytes driven by DGCR8 decrease. These findings suggest that cardiac alterations induced by maternal exposure to high-fat diet is related to abnormalities in TGFβ pathway and associated with down-regulated micro-RNA processing. Our study highlighted DGCR8 as a potential therapeutic target for heart diseases related to early exposure to dietary challenge
A field vegetable transplanter for use in both tilled and no-till soils
A commercial, manually fed vegetable transplanter was modified and adapted to work in no-till soils. Details
of the modifications are described in this article. The aim of this research was to evaluate the performance of this transplanter
under actual field conditions in both tilled and no-till soils. The draft force in the no-till soil was measured for
different working tools mounted for tilling or loosening a narrow band of soil before passing with the furrower. The combination
of a ripper shank opener with a straight nose point resulted in the lowest draft force values per unit of working depth.
The transplanter accuracy and transplant success rate were evaluated in different vegetable crops. The accuracy parameters
(multiple index, miss index, quality of feed index, and precision) were estimated and in general were similar in the tilled
and no-till soils, indicating that the transplanter was able to operate in both soil conditions with the same accuracy. The
transplant success rates were also similar in both soil conditions. The transplanter thus offers a satisfactory technical solution
for transplanting vegetables in both tilled and no-till soils
Low energy trauma in older persons: where to next?
The global population is increasing rapidly with older persons accounting for the greatest proportion. Associated with this rise is an increased rate of injury, including polytrauma, for which low energy falls has become the main cause. The resultant growing impact on trauma resources represents a major burden to the health system. Frailty, with its related issues of cognitive dysfunction and sarcopenia, is emerging as the unifying concept that relates both to the initial event and subsequent outcomes. Strategies to better assess and manage frailty are key to both preventing injury and improving trauma outcomes in the older population and research that links measures of frailty to trauma outcomes will be critical to informing future directions and health policy. The introduction of “Geriatric Emergency Departments” and the development of “Fracture Units” for frail older people will facilitate increased involvement of Geriatricians in trauma care and aid in the education of other health disciplines in the core principles of geriatric assessment and management. Collectively these should lead to improved care and outcomes for both survivors and those requiring end of life decisions and palliation.Mellick Chehade, Tiffany K Gill, Renuka Visvanatha
Legume Cover Crop Alleviates the Negative Impact of No-Till on Tomato Productivity in a Mediterranean Organic Cropping System
The ecosystem services a cover crop (CC) provides depend enormously on species choice and tillage system. Here, we evaluated the impact of (a) three winter CCs-rye (Secale cereale L.) and squarrose clover (Trifolium squarrosum L.) monocultures and their mixture, and (b) two tillage systems-roller-crimping of CC residue as dead mulch for no-till (NT) systems and incorporating CC residue into the soil as green manure for conventional tillage (CT) systems-on the performance of organic processing tomato, i.e., plant growth, nutrient accumulation, fruit yield, and weed biomass. The assessments took place over two years in field experiments conducted under Mediterranean conditions. At the termination time, rye and mixture were the most productive and the best weed-suppressive CCs. During tomato growing season, squarrose clover regardless of tillage system stimulated tomato growth, Nitrogen content and uptake, and the yield relative to the other cover crops. Nevertheless, NT generally impaired the tomato nutritional status and increased weed biomass compared to CT despite some potential weed control by cover crops. These two aspects caused a significant drop in tomato yield in all NT systems. The results suggested that, despite the multiple benefits the compared CCs can offer in Mediterranean agroecosystems, legume CCs could be the key to developing feasible organic vegetable no-till systems
Evaluation of the utility of teaching joint relocations using cadaveric specimens
Published online: 20 March 2018Background: Like other procedural skills, the ability to relocate a joint is an important aspect of junior doctor education. Changes in the approach to teaching and learning from the traditional apprenticeship-style model have made the teaching of practical skills more difficult logistically. Workshops utilising cadaveric specimens offer a solution to this problem. Methods: One hundred forty-six fourth year medical students were randomly divided into 5 groups. Each group received a different teaching intervention based on ankle, patella and hip relocation. The interventions consisted of online learning modules, instructional cards and workshops using skeleton models and cadaveric dislocation models. Following the intervention students were given a test containing multiple choice and true/false style questions. A 13-item 5-point Likert scale questionnaire was also delivered before and after the intervention. The data was analysed using one-way analysis of variance (ANOVA) and the Bonferroni post-hoc test. Results: Compared to the instructional cards group, the other 4 groups showed a 10.8–19.2% improvement in total test score (p < 0.01) and an 18.4–25.3% improvement in self-reported understanding and confidence in performing joint relocations (P < 0.01). There was no significant difference in total test scores between groups exposed to cadaveric instruction on the relocation of one-, two- or all three- joints, nor any significant difference between all the cadaveric dislocation groups and the group receiving instruction on the skeleton model. Conclusion: The results of the present study suggest that workshops utilising cadaveric dislocation models are effective in teaching joint relocation. In addition, the finding that lower fidelity models may be of equal utility may provide institutions with flexibility of delivery needed to meet financial and resource constraints.John Au, Edward Palmer, Ian Johnson and Mellick Chehad
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