199 research outputs found

    Statistical analysis for the impact of smoking on the behavior and health of Qatari adolescents

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    The links between the use of tobacco and health risks are well known. Most of the younger smokers reside in Asia which includes Qatar, the focus country of this study. Cigarette smoking among children is rising at an alarming rate worldwide including Qatar. As youth make up a significant percentage of the population and to achieve the health objectives of the Qatar Vision 2030, it is essential to ensure the health and well-being of adolescents, as they are the future of Qatar. This study focuses on exploring the patterns of tobacco use and its impacts on the adolescents by conducting a survey in different schools across Qatar. The questionnaire was administered in five schools, selected by proportional random sampling. The responses were recorded from the sample for general questions regarding interest in physical activities, relationship with family and friends, mental satisfaction, health, academics and access to cigarettes. 2018 Walter de Gruyter GmbH, Berlin/Boston 2018.Scopu

    Improved calculation of finite element analysis of bipolar coronaincluding ion diffusion

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    This paper presents an iterative method for the analysis of bipolar corona associated with the ionized field around high-voltage bipolar direct-current (HVDC) transmission line conductors. A new finite element technique (FET) is proposed to solve Poisson's equation where the constancy of the conductors' surface field at the corona onset value is directly implemented in the finite element formulation. Satisfying the current continuity condition and updating the space charge density are based on the application of Kirchoff's current balance law at each node of the finite element grid and takes the ion diffusion into account. In order to investigate the effectiveness of the proposed method, a laboratory model was built. It has been found that the calculated V-I characteristics and the ground plane current density profiles agreed well with those measured experimentally. The simplicity in writing the computer program in addition to the low number of iterations required to achieve convergence characterize the new method of analysi

    Improved calculation of finite element analysis of bipolar coronaincluding ion diffusion

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    This paper presents an iterative method for the analysis of bipolar corona associated with the ionized field around high-voltage bipolar direct-current (HVDC) transmission line conductors. A new finite element technique (FET) is proposed to solve Poisson's equation where the constancy of the conductors' surface field at the corona onset value is directly implemented in the finite element formulation. Satisfying the current continuity condition and updating the space charge density are based on the application of Kirchoff's current balance law at each node of the finite element grid and takes the ion diffusion into account. In order to investigate the effectiveness of the proposed method, a laboratory model was built. It has been found that the calculated V-I characteristics and the ground plane current density profiles agreed well with those measured experimentally. The simplicity in writing the computer program in addition to the low number of iterations required to achieve convergence characterize the new method of analysi

    Classification of sedimentary and igneous rocks by laser induced breakdown spectroscopy and nanoparticle-enhanced laser induced breakdown spectroscopy combined with principal component analysis and graph theory

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    In this work, results are presented on the application of standard LIBS and Nanoparticle-Enhanced LIBS (NELIBS) to the classification of rocks (igneous and sedimentary). The classification of the spectra obtained with the two methods was performed using Principal Component Analysis (PCA) and Graph Theory method. The results obtained confirmed the advantages of the LIBS technique in geological applications, showing that excellent classification of the rocks analyzed (more than 99% of the spectra correctly classified) can be obtained using standard LIBS coupled to Graph Theory analysis, while NELIBS spectra, analyzed with the same technique, provide acceptable results, but with 10% of the spectra not classified. These findings are particularly interesting given the application of the LIBS technique in investigating natural samples having porous and/or rough surfaces

    Inception voltage of corona in bipolar ionized fields-effect oncorona power loss

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    In this paper, an iterative finite element based algorithm is presented as a numerical tool for the solution of the bipolar ionized field around high voltage direct current (HVDC) transmission lines. The effect of including unequal values of the positive and negative corona inception voltages and ion mobilities on the corona power loss is investigated. In addition, the effect of ion penetration on reducing the positive conductor corona inception voltage is also studied. The present algorithm is applied to different laboratory and full scale transmission line configurations. Comparison with previously computed V-I characteristics showed that the present computed values were in better agreement with experiments. Also it has been found that the effect of unequal corona inception voltages on the corona power loss (or corona current) is noticeable at applied voltages very near to the inception value

    In vitro MATURATION OF DROMEDARY SHE-CAMEL OOCYTES EXPOSED TO LASER IRRADIATION

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    The objective of this study was to study the effect of laser irradiation on maturation rate of dromedary she-camel oocytes.  Although in vitro fertilization (IVF) technique in she-camel has been established, but maturation rate of camel oocytes is still low comparing with other animal species. Several studies performed to improve in-vitro maturation rate using different types of media with different incubation times. In order to establish high sensitive and low cost maturation improvement technique, laser irradiation has been suggested in the present work. Cumulus oocytes complexes (COCʼs) were collected from ovaries by aspiration method and grade (A) oocytes were chosen and divided into five different groups, 62 oocytes served as control group,  an un-irradiated (group 1), 64 oocytes exposed to 2 minutes of laser irradiation (group 2), 57 oocytes exposed to 3 minutes of laser irradiation (group 3), 49 oocytes exposed to 4 minutes of laser irradiation (group 4) and 52 oocytes exposed to 5 minutes of laser irradiation (group 5) with a total output power of 3 mW for different exposure durations; 2, 3, 4 and 5 minutes.  Afterwards, oocytes were matured in TCM-199 medium at 38.5oC and 5% CO2 in humidified air for 42 h. Maturation rate was calculated based on expulsion of the first polar body and statistically analyzed by one way ANOVA test.   The obtained results showed that, the oocytes reached germinal vesicles (GV) which exposed to laser beam for 5 minutes at 488 nm wavelength represent significantly (P<0.05) the highest value (42.31%) compared to control (not irradiated, 16.13%). However, other groups of GV showed insignificant differences with the control group. The metaphase II (M II) in the control oocytes represents significantly (P<0.05) the highest value (75.81%) compared to 3-5 minutes exposed groups. The degenerated oocytes exposed to laser beam for 5 minutes at 488 nm wavelength represent significantly (P<0.05) the highest value (40.38%) compared to control (not irradiated, 8.06%). In conclusion‚ these results indicated that the exposure of laser irradiation for 2 minutes may improve in-vitro nuclear maturation of immature oocytes in dromedary she-camels as compared to other durations (3-5 minutes) at 488 nm wavelength (blue laser)

    Analytical and mathematical methods for revealing hidden details in ancient manuscripts and paintings: A review

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    In this work, a critical review of the current nondestructive probing and image analysis approaches is presented, to revealing otherwise invisible or hardly discernible details in manuscripts and paintings relevant to cultural heritage and archaeology. Multispectral imaging, X-ray fluorescence, Laser-Induced Breakdown Spectroscopy, Raman spectroscopy and Thermography are considered, as techniques for acquiring images and spectral image sets; statistical methods for the analysis of these images are then discussed, including blind separation and false colour techniques. Several case studies are presented, with particular attention dedicated to the approaches that appear most promising for future applications. Some of the techniques described herein are likely to replace, in the near future, classical digital photography in the study of ancient manuscripts and paintings

    Global economic burden of unmet surgical need for appendicitis

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    Background: There is a substantial gap in provision of adequate surgical care in many low-and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods: Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results: Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US 92492millionusingapproach1and92 492 million using approach 1 and 73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was 95004millionusingapproach1and95 004 million using approach 1 and 75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion: For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially

    Laparoscopy in management of appendicitis in high-, middle-, and low-income countries: a multicenter, prospective, cohort study.

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    BACKGROUND: Appendicitis is the most common abdominal surgical emergency worldwide. Differences between high- and low-income settings in the availability of laparoscopic appendectomy, alternative management choices, and outcomes are poorly described. The aim was to identify variation in surgical management and outcomes of appendicitis within low-, middle-, and high-Human Development Index (HDI) countries worldwide. METHODS: This is a multicenter, international prospective cohort study. Consecutive sampling of patients undergoing emergency appendectomy over 6 months was conducted. Follow-up lasted 30 days. RESULTS: 4546 patients from 52 countries underwent appendectomy (2499 high-, 1540 middle-, and 507 low-HDI groups). Surgical site infection (SSI) rates were higher in low-HDI (OR 2.57, 95% CI 1.33-4.99, p = 0.005) but not middle-HDI countries (OR 1.38, 95% CI 0.76-2.52, p = 0.291), compared with high-HDI countries after adjustment. A laparoscopic approach was common in high-HDI countries (1693/2499, 67.7%), but infrequent in low-HDI (41/507, 8.1%) and middle-HDI (132/1540, 8.6%) groups. After accounting for case-mix, laparoscopy was still associated with fewer overall complications (OR 0.55, 95% CI 0.42-0.71, p < 0.001) and SSIs (OR 0.22, 95% CI 0.14-0.33, p < 0.001). In propensity-score matched groups within low-/middle-HDI countries, laparoscopy was still associated with fewer overall complications (OR 0.23 95% CI 0.11-0.44) and SSI (OR 0.21 95% CI 0.09-0.45). CONCLUSION: A laparoscopic approach is associated with better outcomes and availability appears to differ by country HDI. Despite the profound clinical, operational, and financial barriers to its widespread introduction, laparoscopy could significantly improve outcomes for patients in low-resource environments. TRIAL REGISTRATION: NCT02179112
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