102 research outputs found
A comparative study of 3D printed non-imaging solar V-trough and compound parabolic concentrators for low-cost, high-performance CPV applications
Non-imaging solar concentrators are capable of increasing power output and reducing the cost of photovoltaic (PV) cells. This paper discusses the performance of non-imaging concentrators with two distinct configurations: V-trough and compound parabolic. The concentrators were successfully designed, fabricated, tested and characterized as reported in our previous papers [1, 2]. Herein, we present a comprehensive comparison between those non-imaging concentrators in terms of concentration ratio, power output, conversion efficiency, optical efficiency, light uniformity, angular response and cost. The results demonstrate the advantages of using V-trough and compound parabolic concentrators, particularly beneficial to be employed as the secondary optical elements with a primary concentrator and high-cost III-V cells such as GaInP/GaAs/Ge
Major depressive disorder, personality disorders and coping strategies are independent risk factors for lower quality of life in non-metastatic breast cancer patients.
International audienceObjective: To identify risk factors for lower quality of life (QOL) in non-metastatic breast cancer patients.Methods: Our study included 120 patients from the University Hospital Centers of Tours and Poitiers. This cross-sectional study was conducted 7 months after patients’ breast cancer diagnosis and assessed QOL (Quality of Life Questionnaire-Core 30 = QLQ-C30), socio-demographic characteristics, coping strategies (Brief-Cope), physiological and biological variables (e.g., initial tumor severity, types of treatment received), the existence of major depressive disorder (Mini International Neuropsychiatric Interview) and pain severity (QDSA). We assessed personality disorders 3 months after diagnosis (VKP questionnaire). We used multiple linear regression models to determine which factors were associated with physical, emotional and global QOL. Results: Lower physical QOL was associated with major depressive disorder, younger age, a more severe initial tumor stage and the use of the behavioral disengagement coping. Lower emotional QOL was associated with major depressive disorder, the existence of a personality disorder, a more severe pain level, higher use of self-blame and lower use of acceptance coping strategies. Lower global QOL was associated with major depressive disorder, the existence of a personality disorder, a more severe pain level, higher use of self-blame and lower use of positive reframing coping strategies and an absence of hormone therapy.Conclusions: Lower QOL scores were more strongly associated to variables related to the individual’s premorbid psychological characteristics and the manner in which this individual copes with the cancer (e.g., depression, personality and coping) than to cancer-related variables (e.g., treatment types, cancer severity)
Understandings of scientific inquiry: an international collaborative investigation of seventh grade students
Although understandings of scientific inquiry (as opposed to conducting inquiry) is included in science
education reform documents around the world, little is known about what students have learned about inquiry
during their primary school years. This is partially due to the lack of any assessment instrument to measure
understandings about scientific inquiry. However, a valid and reliable assessment has recently been developed
and published, Views About Scientific Inquiry (VASI) (Lederman J. et. al., 2014). The purpose of this large
scale (i.e., 19 countries spanning six continents and including 2,960 students) international project was to get
the first baseline data on what grade students have learned. The participating countries were: Australia,
Brazil, Canada, Chile, China, Egypt, England, Finland, France, Germany, Israel, New Zealand, Nigeria, South
Africa, Spain, Sweden, United States, Taiwan, and Turkey. In many countries, science is not formally taught
until middle school, which is the rationale for choosing seventh grade students for this investigation. This
baseline data will simultaneously provide information on what, if anything, students learn about inquiry in
primary school, as well as their beginning knowledge as they enter secondary school
Heart echinococcus cyst as an incidental finding: early detection might be life-saving
We present a 46-year-old female smoker who was admitted to the emergency department of our hospital due to cough with blood-tinged sputum for the last four days before admission. Using echocardiography and Multi-Detector Computed Tomography (MDCT) heart Echinococcosis was diagnosed. Echinococcosis is a severe health issue in some geographical regions of the world. Hydatid infection of the heart is rare and the clinical presentation is usually insidious but there is always the lethal hazard of cyst perforation. Early diagnosis and an integrated treatment strategy are crucial. The results of surgical treatment of heart echinococcosis are better than the conservative strategy only. Extraction of the cyst combined with chemotherapy peri or post operative aiming to decrease the recurrences, consists the lege artis method of encountering this medical entity. Surgical excision was performed and the patient had an uneventful recovery and follow up at six and twelve months
Edge states in a two-dimensional honeycomb lattice of massive magnetic skyrmions
We study the collective dynamics of a two-dimensional honeycomb lattice of
magnetic skyrmions. By performing large-scale micromagnetic simulations, we
find multiple chiral and non-chiral edge modes of skyrmion oscillations in the
lattice. The non-chiral edge states are due to the Tamm-Shockley mechanism,
while the chiral ones are topologically protected against structure defects and
hold different handednesses depending on the mode frequency. To interpret the
emerging multiband nature of the chiral edge states, we generalize the massless
Thiele's equation by including a second-order inertial term of skyrmion mass as
well as a third-order non-Newtonian gyroscopic term, which allows us to model
the band structure of skrymion oscillations. Theoretical results compare well
with numerical simulations. Our findings uncover the importance of high order
effects in strongly coupled skyrmions and are helpful for designing novel
topological devices.Comment: 6 pages,4 figures,accepted by Physical Review B as a Rapid
Communicatio
International collaborative follow - up investigation of graduating high school students’ understandings of the nature of scientific inquiry: is progress Being made?
Understandings of the nature of scientific inquiry (NOSI), as opposed to engaging students in inquiry learning experiences, are included in science education reform documents around the world. However, little is known about what students have learned about NOSI during their pre-college school years. The purpose of this large-scale follow-up international project (i.e. 32 countries and regions, spanning six continents and including 3917 students for the high school sample) was to collect data on what exiting high school students have learned about NOSI. Additionally, the study investigated changes in 12th grade students’ NOSI understandings compared to seventh grade (i.e. 20 countries and regions) students’ understandings from a prior investigation [Lederman et al. (2019). An international collaborative investigation of beginning seventh grade students’ understandings of scientific inquiry: Establishing a baseline. Journal of Research in Science Teaching, 56(4), 486–515. https://doi.org/10.1002/tea.21512]. This study documents and discusses graduating high school students’ understandings and compares their understandings to seventh grade students’ understandings of the same aspects of scientific inquiry for each country. It is important to note that collecting data from each of the 130+ countries globally was not feasible. Similarly, it was not possible to collect data from every region of each country. A concerted effort was made, however, to provide a relatively representative picture of each country and the world
Immunoglobulin, glucocorticoid, or combination therapy for multisystem inflammatory syndrome in children: a propensity-weighted cohort study
Background: Multisystem inflammatory syndrome in children (MIS-C), a hyperinflammatory condition associated with SARS-CoV-2 infection, has emerged as a serious illness in children worldwide. Immunoglobulin or glucocorticoids, or both, are currently recommended treatments. Methods: The Best Available Treatment Study evaluated immunomodulatory treatments for MIS-C in an international observational cohort. Analysis of the first 614 patients was previously reported. In this propensity-weighted cohort study, clinical and outcome data from children with suspected or proven MIS-C were collected onto a web-based Research Electronic Data Capture database. After excluding neonates and incomplete or duplicate records, inverse probability weighting was used to compare primary treatments with intravenous immunoglobulin, intravenous immunoglobulin plus glucocorticoids, or glucocorticoids alone, using intravenous immunoglobulin as the reference treatment. Primary outcomes were a composite of inotropic or ventilator support from the second day after treatment initiation, or death, and time to improvement on an ordinal clinical severity scale. Secondary outcomes included treatment escalation, clinical deterioration, fever, and coronary artery aneurysm occurrence and resolution. This study is registered with the ISRCTN registry, ISRCTN69546370. Findings: We enrolled 2101 children (aged 0 months to 19 years) with clinically diagnosed MIS-C from 39 countries between June 14, 2020, and April 25, 2022, and, following exclusions, 2009 patients were included for analysis (median age 8·0 years [IQR 4·2–11·4], 1191 [59·3%] male and 818 [40·7%] female, and 825 [41·1%] White). 680 (33·8%) patients received primary treatment with intravenous immunoglobulin, 698 (34·7%) with intravenous immunoglobulin plus glucocorticoids, 487 (24·2%) with glucocorticoids alone; 59 (2·9%) patients received other combinations, including biologicals, and 85 (4·2%) patients received no immunomodulators. There were no significant differences between treatments for primary outcomes for the 1586 patients with complete baseline and outcome data that were considered for primary analysis. Adjusted odds ratios for ventilation, inotropic support, or death were 1·09 (95% CI 0·75–1·58; corrected p value=1·00) for intravenous immunoglobulin plus glucocorticoids and 0·93 (0·58–1·47; corrected p value=1·00) for glucocorticoids alone, versus intravenous immunoglobulin alone. Adjusted average hazard ratios for time to improvement were 1·04 (95% CI 0·91–1·20; corrected p value=1·00) for intravenous immunoglobulin plus glucocorticoids, and 0·84 (0·70–1·00; corrected p value=0·22) for glucocorticoids alone, versus intravenous immunoglobulin alone. Treatment escalation was less frequent for intravenous immunoglobulin plus glucocorticoids (OR 0·15 [95% CI 0·11–0·20]; p<0·0001) and glucocorticoids alone (0·68 [0·50–0·93]; p=0·014) versus intravenous immunoglobulin alone. Persistent fever (from day 2 onward) was less common with intravenous immunoglobulin plus glucocorticoids compared with either intravenous immunoglobulin alone (OR 0·50 [95% CI 0·38–0·67]; p<0·0001) or glucocorticoids alone (0·63 [0·45–0·88]; p=0·0058). Coronary artery aneurysm occurrence and resolution did not differ significantly between treatment groups. Interpretation: Recovery rates, including occurrence and resolution of coronary artery aneurysms, were similar for primary treatment with intravenous immunoglobulin when compared to glucocorticoids or intravenous immunoglobulin plus glucocorticoids. Initial treatment with glucocorticoids appears to be a safe alternative to immunoglobulin or combined therapy, and might be advantageous in view of the cost and limited availability of intravenous immunoglobulin in many countries. Funding: Imperial College London, the European Union's Horizon 2020, Wellcome Trust, the Medical Research Foundation, UK National Institute for Health and Care Research, and National Institutes of Health
Immunoglobulin, glucocorticoid, or combination therapy for multisystem inflammatory syndrome in children: a propensity-weighted cohort study
Background Multisystem inflammatory syndrome in children (MIS-C), a hyperinflammatory condition associated with SARS-CoV-2 infection, has emerged as a serious illness in children worldwide. Immunoglobulin or glucocorticoids, or both, are currently recommended treatments. Methods The Best Available Treatment Study evaluated immunomodulatory treatments for MIS-C in an international observational cohort. Analysis of the first 614 patients was previously reported. In this propensity-weighted cohort study, clinical and outcome data from children with suspected or proven MIS-C were collected onto a web-based Research Electronic Data Capture database. After excluding neonates and incomplete or duplicate records, inverse probability weighting was used to compare primary treatments with intravenous immunoglobulin, intravenous immunoglobulin plus glucocorticoids, or glucocorticoids alone, using intravenous immunoglobulin as the reference treatment. Primary outcomes were a composite of inotropic or ventilator support from the second day after treatment initiation, or death, and time to improvement on an ordinal clinical severity scale. Secondary outcomes included treatment escalation, clinical deterioration, fever, and coronary artery aneurysm occurrence and resolution. This study is registered with the ISRCTN registry, ISRCTN69546370. Findings We enrolled 2101 children (aged 0 months to 19 years) with clinically diagnosed MIS-C from 39 countries between June 14, 2020, and April 25, 2022, and, following exclusions, 2009 patients were included for analysis (median age 8·0 years [IQR 4·2–11·4], 1191 [59·3%] male and 818 [40·7%] female, and 825 [41·1%] White). 680 (33·8%) patients received primary treatment with intravenous immunoglobulin, 698 (34·7%) with intravenous immunoglobulin plus glucocorticoids, 487 (24·2%) with glucocorticoids alone; 59 (2·9%) patients received other combinations, including biologicals, and 85 (4·2%) patients received no immunomodulators. There were no significant differences between treatments for primary outcomes for the 1586 patients with complete baseline and outcome data that were considered for primary analysis. Adjusted odds ratios for ventilation, inotropic support, or death were 1·09 (95% CI 0·75–1·58; corrected p value=1·00) for intravenous immunoglobulin plus glucocorticoids and 0·93 (0·58–1·47; corrected p value=1·00) for glucocorticoids alone, versus intravenous immunoglobulin alone. Adjusted average hazard ratios for time to improvement were 1·04 (95% CI 0·91–1·20; corrected p value=1·00) for intravenous immunoglobulin plus glucocorticoids, and 0·84 (0·70–1·00; corrected p value=0·22) for glucocorticoids alone, versus intravenous immunoglobulin alone. Treatment escalation was less frequent for intravenous immunoglobulin plus glucocorticoids (OR 0·15 [95% CI 0·11–0·20]; p<0·0001) and glucocorticoids alone (0·68 [0·50–0·93]; p=0·014) versus intravenous immunoglobulin alone. Persistent fever (from day 2 onward) was less common with intravenous immunoglobulin plus glucocorticoids compared with either intravenous immunoglobulin alone (OR 0·50 [95% CI 0·38–0·67]; p<0·0001) or glucocorticoids alone (0·63 [0·45–0·88]; p=0·0058). Coronary artery aneurysm occurrence and resolution did not differ significantly between treatment groups. Interpretation Recovery rates, including occurrence and resolution of coronary artery aneurysms, were similar for primary treatment with intravenous immunoglobulin when compared to glucocorticoids or intravenous immunoglobulin plus glucocorticoids. Initial treatment with glucocorticoids appears to be a safe alternative to immunoglobulin or combined therapy, and might be advantageous in view of the cost and limited availability of intravenous immunoglobulin in many countries. Funding Imperial College London, the European Union's Horizon 2020, Wellcome Trust, the Medical Research Foundation, UK National Institute for Health and Care Research, and National Institutes of Health
تصميم رقاقة ماصة جديدة ذات بنية تجزيئية مكونة من مواد Metamaterial لتخفيض تأثير الأمواج الكهرومغناطيسية على الإنسان
ركزت الأبحاث العلمية في السنوات الأخيرة على تطوير بنى المواد المستخدمة وطرق تعاملها مع الأشعة الكهرومغناطيسية لإعطاء مواصفات خاصة وفقاً لاستخدامها العملي، حتى حصل الباحثون على مواد Metamaterial ووجدوا أنها تمتلك خصائص جديدة غير موجودة في الطبيعة فهي تعطي عند تفاعلها مع الأمواج الكهرومغناطيسية سماحية كهربائية (ɛ) ونفاذية مغناطيسية (µ) سالبتين. وبفضل هذه الخصائص الفريدة لمواد Metamaterial فقد أصبح تصميمها واستخدامها موضوعاً شائعاً في عدة مجالات أهمها مجال الاتصالات الميكروية والضوئية.
كما ازداد الاهتمام باستخدام الهندسة التجزيئية لما لها من دور في الحصول على نطاقات متعددة وعرض حزمة واسع وإمكانية التحكم بتردد الرنين، وإعطاء برامترات أكثر في التصميم.
في هذا البحث تم اقتراح تصميم رقاقة تعمل كممتص مكون من مواد Metamaterial مزدوج النطاق استناداً إلى بنية مينكويسكي في الهندسة التجزيئية، وقد تم الحصول على نسب امتصاص عالية ( 99%) في نطاق ترددات GSM، وذلك باستخدام برنامج المحاكاة الحاسوبي CST
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