650 research outputs found
Experimental Identification of Modal Density Parameters of Light Weight Structures
A basic requirement for the analysis of vibro-acoustic problems by means of the Statistical Energy Analysis (SEA) is the knowledge of modal densities of the tested subsystems. For simple structures, modal densities are obtained by theoretical solutions. The application of the SEA to complex light weight structures often leads to sophisticated subsystems the modal densities of which cannot be received from theoretical solutions. Therefore, experimental procedures for the identification of modal densities are needed. This paper describes an experimental method based on the theoretical relation between the modal density and the real part of the point admittance, the conductance. Simulations of a simply supported rectangular plate show the accuracy and the limits of the method A steel plate and a thin-walled cylinder made offiber composite material have been thoroughly investigated by experiments. By this, the influence of the mass correction of the measured conductances is discussed in the paper. The experimental results are compared with theoretical results obtained from the code AutoSEA2. For medium and higher frequencies the results are in fairly good agreement
DETERMINATION OF DIVERSE ENVIRONMENTAL POLLUTION LEVEL FROM SELECTED AREAS OF RAWALPINDI, PAKISTAN
Anthropogenic contaminants arising from both stationary (power plants, industries and residential heating) and mobile sources (road traffic) can harm ambient air quality in urban areas. Depending upon their physical state, these pollutants are classified as liquid and vapor phases and are subsequently transported to the Earth’s surface through dry and wet deposition. After the deposition of these pollutants onto the surface of earth various health effects caused by these pollutants occurred like cardiovascular diseases and hypertension. In this study four different locations/sites were selected from the Rawalpindi city depending upon the population, traffic rush and industries to examine the noise level, concentration of carbon dioxide and heavy metals. Air sampler was used for the collection of air sample to analyze the heavy metal concentration, Quest electronic sound meter for measuring sound level and SIBATA for CO2 measurement. The study findings revealed that noise level was higher at all selected locations as described by WHO limit (70 dB) being highest at Industrial area due to heavy machinery and lowest at green area. Concentration of all four heavy metals were high as compared with the prescribed limits. CO2 level reaches up to 300 ppm because of coal consumption during the winter season. The threshold values of all these selected parameters well above the prescribed limits defined by the authorities so to combat with this situation we should move towards more energy efficient fuels, proper maintenance of vehicles and machineries, traffic management and installation of noise barriers in industries as well as installation of catalytic convertors in vehicles to stop further air pollution
A Robust Deep Model for Classification of Peptic Ulcer and Other Digestive Tract Disorders Using Endoscopic Images
Accurate patient disease classification and detection through deep-learning (DL) models are increasingly contributing to the area of biomedical imaging. The most frequent gastrointestinal (GI) tract ailments are peptic ulcers and stomach cancer. Conventional endoscopy is a painful and hectic procedure for the patient while Wireless Capsule Endoscopy (WCE) is a useful technology for diagnosing GI problems and doing painless gut imaging. However, there is still a challenge to investigate thousands of images captured during the WCE procedure accurately and efficiently because existing deep models are not scored with significant accuracy on WCE image analysis. So, to prevent emergency conditions among patients, we need an efficient and accurate DL model for real-time analysis. In this study, we propose a reliable and efficient approach for classifying GI tract abnormalities using WCE images by applying a deep Convolutional Neural Network (CNN). For this purpose, we propose a custom CNN architecture named GI Disease-Detection Network (GIDD-Net) that is designed from scratch with relatively few parameters to detect GI tract disorders more accurately and efficiently at a low computational cost. Moreover, our model successfully distinguishes GI disorders by visualizing class activation patterns in the stomach bowls as a heat map. The Kvasir-Capsule image dataset has a significant class imbalance problem, we exploited a synthetic oversampling technique BORDERLINE SMOTE (BL-SMOTE) to evenly distribute the image among the classes to prevent the problem of class imbalance. The proposed model is evaluated against various metrics and achieved the following values for evaluation metrics: 98.9%, 99.8%, 98.9%, 98.9%, 98.8%, and 0.0474 for accuracy, AUC, F1-score, precision, recall, and loss, respectively. From the simulation results, it is noted that the proposed model outperforms other state-of-the-art models in all the evaluation metrics
Aligned copper nanorod arrays for highly efficient generation of intense ultra-broadband THz pulses
We demonstrate an intense broadband terahertz (THz) source based on the interaction of relativistic-intensity femtosecond lasers with aligned copper nanorod array targets. For copper nanorod targets with a length of 5 μm, a maximum 13.8 times enhancement in the THz pulse energy (in ≤20 THz spectral range) is measured as compared to that with a thick plane copper target under the same laser conditions. A further increase in the nanorod length leads to a decrease in the THz pulse energy at medium frequencies (≤20 THz) and increase of the electromagnetic pulse energy in the high-frequency range (from 20–200 THz). For the latter, we measure a maximum energy enhancement of 28 times for the nanorod targets with a length of 60 μm. Particle-in-cell simulations reveal that THz pulses are mostly generated by coherent transition radiation of laser produced hot electrons, which are efficiently enhanced with the use of nanorod targets. Good agreement is found between the simulation and experimental results
Enhancing HIV treatment access and outcomes amongst HIV infected children and adolescents in resource limited settings
INTRODUCTION : Increasing access to HIV-related
care and treatment for children aged 0–18 years in
resource-limited settings is an urgent global priority. In
2011–2012 the percentage increase in children accessing
antiretroviral therapy was approximately half that of adults
(11 vs. 21 %). We propose a model for increasing access
to, and retention in, paediatric HIV care and treatment in
resource-limited settings. METHODS : Following a rapid
appraisal of recent literature seven main challenges in
paediatric HIV-related care and treatment were identified:
(1) lack of regular, integrated, ongoing HIV-related diagnosis;
(2) weak facility-based systems for tracking and
retention in care; (3) interrupted availability of dried blood
spot cards (expiration/stock outs); (4) poor quality control
of rapid HIV testing; (5) supply-related gaps at health
facility-laboratory interface; (6) poor uptake of HIV testing,
possibly relating to a fatalistic belief about HIV infection; (7) community-associated reasons e.g. non-disclosure
and weak systems for social support, resulting in
poor retention in care. RESULTS : To increase sustained access
to paediatric HIV-related care and treatment, regular
updating of Policies, review of inter-sectoral Plans (at
facility and community levels) and evaluation of Programme
implementation and impact (at national, subnational,
facility and community levels) are non-negotiable
critical elements. Additionally we recommend the intensified
implementation of seven main interventions: (1)
update or refresher messaging for health care staff and
simple messaging for key staff at early childhood development
centres and schools; (2) contact tracing, disclosure
and retention monitoring; (3) paying particular attention to
infant dried blood spot (DBS) stock control; (4) regular
quality assurance of rapid HIV testing procedures; (5)
workshops/meetings/dialogues between health facilities
and laboratories to resolve transport-related gaps and to
facilitate return of results to facilities; (6) community leader
and health worker advocacy at creches, schools, religious
centres to increase uptake of HIV testing and dispel
fatalistic beliefs about HIV; (7) use of mobile communication
technology (m-health) and peer/community supporters
to maintain contact with patients. DISCUSSION AND CONCLUSION : We propose that this package of facility,community and family-orientated interventions are needed to change the trajectory of the paediatric HIV epidemic and its associated patterns of morbidity and mortality, thus achieving the double dividend of improving HIV-free
survival.South African Medical Research Council.http://link.springer.com/journal/10995hb2016Paediatrics and Child Healt
Who Commits to the Rule of Law? Constrained Government and Foreign Direct Investment in Postcommunist States
Research linking credible commitments to the rule of law in terms of property rights and contract enforcement is a hallmark of recent efforts to explain economic growth and development. However, many postcommunist states have had difficulty making such commitments and spurring growth. Many argue political polarization prevents states from reforming laws and protecting property rights in some countries whereas single-party governance renders state promises incredible in others. I analyze pooled cross-sectional time-series data for twenty-four postcommunist countries and provide evidence effective constraints among elected officials act as democratic commitment mechanisms rendering government policies credible
The evolution of tooth wear indices
Tooth wear—attrition, erosion and abrasion—is perceived internationally as an ever-increasing problem. Clinical and epidemiological studies, however, are difficult to interpret and compare due to differences in terminology and the large number of indices that have been developed for diagnosing, grading and monitoring dental hard tissue loss. These indices have been designed to identify increasing severity and are usually numerical. Some record lesions on an aetiological basis (e.g. erosion indices), others record lesions irrespective of aetiology (tooth wear indices); none have universal acceptance, complicating the evaluation of the true increase in prevalence reported. This article considers the ideal requirements for an erosion index. It reviews the literature to consider how current indices have evolved and discusses if these indices meet the clinical and research needs of the dental profession
Pulmonary Hypertension in Elderly Patients with Diastolic Dysfunction and Preserved Ejection Fraction
Abstract: Purpose: Patients with diastolic dysfunction may have a disproportionate degree of elevation in pulmonary pressure, particularly in the elderly. Higher pulmonary vascular resistance in the elderly patients with heart failure but preserved ejection fraction suggests that beyond the post-capillary contribution of pulmonary venous congestion, a pre-capillary component of pulmonary arterial hypertension occurs. We aim to identify if pulmonary vascular resistance in elderly patients with diastolic dysfunction is disproportionately higher than patients with systolic dysfunction independent of filling pressures. Methods: 389 patients identified retrospectively between 2003- 2010; elderly with preserved ejection fraction, elderly with depressed ejection fraction, and primary arterial hypertension who underwent right-heart catheterization at Rush University. Results: No significant difference in pulmonary vascular resistance between systolic and diastolic dysfunction. The mean difference in pulmonary vascular resistance was not statistically significant at 0.40 mmHg·min/l (95 % CI-3.03 to 3.83) with similar left ventricular filling pressures with mean difference of 3.38 mmHg (95 % CI,-1.27 to 8.02). When adjusted for filling pressures, there remained no difference in pulmonary vascular resistance for systolic and diastolic dysfunction. The mean pulmonary vascular resistance is more elevated in systolic heart failure compared to diastolic heart failure with means 3.13 mmHg·min/l and 3.52 mmHg·min/l, respectively
The transfer and fate of Pb from sewage sludge amended soil in a multi-trophic food chain: a comparison with the labile elements Cd and Zn
The contamination of agroecosystems due to the presence of trace elements in commonly used agricultural materials is a serious issue. The most contaminated material is usually sewage sludge, and the sustainable use of this material within agriculture is a major concern. This study addresses a key issue in this respect, the fate of trace metals applied to soil in food chains. The work particularly addresses the transfer of Pb, which is an understudied element in this respect, and compares the transfer of Pb with two of the most labile metals, Cd and Zn. The transfer of these elements was determined from sludge-amended soils in a food chain consisting of Indian mustard (Brassica juncea), the mustard aphid (Lipaphis erysimi) and a predatory beetle (Coccinella septempunctata). The soil was amended with sludge at rates of 0, 5, 10 and 20 % (w/w). Results showed that Cd was readily transferred through the food chain until the predator trophic level. Zn was the most readily transferred element in the lower trophic levels, but transfer to aphids was effectively restricted by the plant regulating shoot concentration. Pb had the lowest level of transfer from soil to shoot and exhibited particular retention in the roots. Nevertheless, Pb concentrations were significantly increased by sludge amendment in aphids, and Pb was increasingly transferred to ladybirds as levels increased. The potential for Pb to cause secondary toxicity to organisms in higher trophic levels may have therefore been underestimated
CoronaHiT: high-throughput sequencing of SARS-CoV-2 genomes.
We present CoronaHiT, a platform and throughput flexible method for sequencing SARS-CoV-2 genomes (≤ 96 on MinION or > 96 on Illumina NextSeq) depending on changing requirements experienced during the pandemic. CoronaHiT uses transposase-based library preparation of ARTIC PCR products. Method performance was demonstrated by sequencing 2 plates containing 95 and 59 SARS-CoV-2 genomes on nanopore and Illumina platforms and comparing to the ARTIC LoCost nanopore method. Of the 154 samples sequenced using all 3 methods, ≥ 90% genome coverage was obtained for 64.3% using ARTIC LoCost, 71.4% using CoronaHiT-ONT and 76.6% using CoronaHiT-Illumina, with almost identical clustering on a maximum likelihood tree. This protocol will aid the rapid expansion of SARS-CoV-2 genome sequencing globally.The sequencing costs were funded by the COVID-19 Genomics UK (COG-UK) Consortium which is supported by funding from the Medical Research Council (MRC) part of UK Research & Innovation (UKRI), the National Institute of Health Research (NIHR) and Genome Research Limited, operating as the Wellcome Sanger Institute
- …