105 research outputs found
Aviation liberalisation as a means of promoting international tourism: Comparing Morocco and Tunisia
The dynamics, in terms of air services and international leisure mobility (both of tourism and visits to friends and relatives [VFRs]), between the European Union (EU) and both Morocco and Tunisia, were compared. Indeed, the EU-Morocco market became liberalized after 2006. Significant dynamics then occurred on both the airline and travel sides. However, it is difficult to assess the extent to which aviation liberalization has been the cause of all of these changes. This suggests a comparison with the more regulated and more protected EU-Tunisia market. The results will be useful in light of negotiations to promote open-skies agreements
Radium and Uranium Concentrations of Powder Juice in the Iraq Markets Using CR-39 Detector
استخدمت مسحوق العصائر بصورة واسعة بسبب رخص ثمنها مقارنة بالعصائر الطازجة. هذه العصائر ربما تحتوي على بعض المواد المشعة. كان الهدف من الدراسة قياس تراكيز الراديوم واليورانيوم في بعض الانواع المختارة من الاسواق لمسحوق العصائر الاكثر استخداما. قيست تراكيز العناصر المشعة باستخدام تقنية كاشف CR-39 الموضوع في اناء مغلق. تركيز فعالية الرادون في هذه الدراسة كانت ضمن المدى 57.146 -151.129 Bq/m3 وبقيمة متوسطة 107.62 Bq/m3. وهي ضمن الحدود المقبولة 100 Bq/m3 لمنظمة الصحة العالمية (WHO), واقل من 200 Bq/m3 التي هي مستوى لوائح الوقاية الوطنية الاوربية. الجرعة السنوية الفعالة للرادون تغيرت بين 1.441-3.813 mSv/y وهي ضمن المدى 0.2-10 mSv/y المحدد من قبل (UNSCEAR). تركيز الراديوم وجد بانه يتغير بين القيم 0.188-0.498 Bq/kg وبقيمة متوسطة 0.354 Bq/kg. والجرعة السنوية الفعالة للراديوم كانت ضمن المدى 1.050-2.779 μSv/y. تركيز اليورانيوم تغيرت بين 0.150-0.398 ppm وبقيمة متوسطة 0.283 ppm. والجرعة السنوية الفعالة لليورانيوم كانت ضمن المدى 1.669-4.414 μSv/y. هذا البحث يساهم في تعريف وقياس الفعالية المحددة للعناصر المشعة الموجودة في مسحوق العصائر المتناولة بكثرة في العراق وبينت الدراسة ان هذه الانواع من العصائر امنة للاستهلاك.Powder juices are widely used by the people in the study area because its low price compared to fresh juices. These powder juices may contain some radioactive materials. The study aimed to measure radioactivity concentrations of Radium and Uranium in the most used kinds of powder juice samples, selected from Iraq markets. CR-39 detector with sealed can technique, used to measure the radioactive elements concentrations. The radionuclides observed in the present work are, the estimated radon activity concentration range is between 57.146-151.129 Bq/m3 with a mean value of 107.62 Bq/m3. The radon concentration mean value is within of 100 Bq/m3 the limits of (WHO) World Health Organization reference level, below of (NRPB) UK National Radiation Protection Board, and below of 200 Bq/m3 the European Commission Recommendation Level. The annual effective dose of radon varied between 1.441-3.813 mSv/y, are within the (UNSCEAR) range 0.2-10 mSv/y. Radium contents were found to vary between 0.188-0.498 Bq/kg and a mean value of 0.354 Bq/kg. The radium effective annual dose ranged between 1.050-2.779 μSv/y. The concentrations of uranium are in the range between 0.150-0.398 ppm with men value of 0.283 ppm. The effective annual dose of uranium varied between 1.669-4.414 μSv/y. This work helped in identifying and measuring the specified activity of radionuclide present in powdered fruit juices consuming in Iraq and showed that these kinds of powder juice are safe for consumption
Assessing the impacts of aviation liberalisation on tourism: some methodological considerations derived from the Moroccan and Tunisian cases
At a time when the liberalisation of air transport is increasingly being promoted as a means to induce the growth of the tourism business, it is striking that there is little evidence to suggest that such liberalisation has indeed led to a growth in tourism. Furthermore, the evidence is usually restricted to the impacts of sole low-cost airlines on tourist destinations newly served by such airlines. In contrast to various ideological or naïve statements, this paper shows that assessing the relationship between liberalised air markets and trends in tourism is challenging. On the transport side, aviation liberalisation is rarely considered as a dimension that can be measured accurately; similar protected markets are not considered for comparison; and trends in charter flights are neglected. On the tourist side, broad definitions of so-called tourists are usually considered and include immigrants visiting their home country; nights spent are neglected, despite a possible trend in declining length of stay; and substitution between places is usually disregarded, as are the long-term effects
La libéralisation du transport aérien pour promouvoir le tourisme international : une comparaison du Maroc et de la Tunisie
La libéralisation du transport aérien pour promouvoir le tourisme international : une comparaison du Maroc et de la Tunisi
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Efficient power management strategy of electric vehicles based hybrid renewable energy
This article belongs to the Special Issue Future Perspectives of Safety and Reliability Assessment for Electric-Powered Vehicles.Copyright © 2021 by the authors. This paper presents a straightforward power management algorithm that supervises the contribution of more than one energy source for charging a vehicle, even if the car is in motion. The system is composed of a wireless charging system, photovoltaic (PV) generator, fuel cell (FC), and a battery system. It also contains a group of power converters associated with each energy resource to make the necessary adaptation between the input and output electrical signals. The boost converter relates to the PV/FC, and the boost–buck converter is connected with the battery pack. In this work, the wireless charging, FC, and PV systems are connected in parallel via a DC/DC converter for feeding the battery bank when the given energy is in excess. Therefore, for each of these elements, the mathematical model is formulated, then the corresponding power management loop is built, which presents the significant contribution of this paper. The efficient power management methodology proposed in this work was verified on Matlab/Simulink platforms. The battery state of charge and the hydrogen consumption obtained results were compared to show the effectiveness of this multi-source system
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Remarkable performance recovery in highly defective perovskite solar cells by photo-oxidation
Exposure to environmental factors is generally expected to cause degradation in perovskite films and solar cells. Herein, we show that films with certain defect profiles can display the opposite effect, healing upon exposure to oxygen under illumination. We tune the iodine content of methylammonium lead triiodide perovskite from understoichiometric to overstoichiometric and expose them to oxygen and light prior to the addition of the top layers of the device, thereby examining the defect dependence of their photooxidative response in the absence of storage-related chemical processes. The contrast between the photovoltaic properties of the cells with different defects is stark. Understoichiometric samples indeed degrade, demonstrating performance at 33% of their untreated counterparts, while stoichiometric samples maintain their performance levels. Surprisingly, overstoichiometric samples, which show low current density and strong reverse hysteresis when untreated, heal to maximum performance levels (the same as untreated, stoichiometric samples) upon the photooxidative treatment. A similar, albeit smaller-scale, effect is observed for triple cation and methylammonium-free compositions, demonstrating the general application of this treatment to state-of-the-art compositions. We examine the reasons behind this response by a suite of characterization techniques, finding that the performance changes coincide with microstructural decay at the crystal surface, reorientation of the bulk crystal structure for the understoichiometric cells, and a decrease in the iodine-to-lead ratio of all films. These results indicate that defect engineering is a powerful tool to manipulate the stability of perovskite solar cells
Overall Survival with Adjuvant Pembrolizumab in Renal-Cell Carcinoma
BackgroundAdjuvant pembrolizumab therapy after surgery for renal-cell carcinoma was approved on the basis of a significant improvement in disease-free survival in the KEYNOTE-564 trial. Whether the results regarding overall survival from the third prespecified interim analysis of the trial would also favor pembrolizumab was uncertain.MethodsIn this phase 3, double-blind, placebo-controlled trial, we randomly assigned (in a 1:1 ratio) participants with clear-cell renal-cell carcinoma who had an increased risk of recurrence after surgery to receive pembrolizumab (at a dose of 200 mg) or placebo every 3 weeks for up to 17 cycles (approximately 1 year) or until recurrence, the occurrence of unacceptable toxic effects, or withdrawal of consent. A significant improvement in disease-free survival according to investigator assessment (the primary end point) was shown previously. Overall survival was the key secondary end point. Safety was a secondary end point.Download a PDF of the Research Summary.ResultsA total of 496 participants were assigned to receive pembrolizumab and 498 to receive placebo. As of September 15, 2023, the median follow-up was 57.2 months. The disease-free survival benefit was consistent with that in previous analyses (hazard ratio for recurrence or death, 0.72; 95% confidence interval [CI], 0.59 to 0.87). A significant improvement in overall survival was observed with pembrolizumab as compared with placebo (hazard ratio for death, 0.62; 95% CI, 0.44 to 0.87; P=0.005). The estimated overall survival at 48 months was 91.2% in the pembrolizumab group, as compared with 86.0% in the placebo group; the benefit was consistent across key subgroups. Pembrolizumab was associated with a higher incidence of serious adverse events of any cause (20.7%, vs. 11.5% with placebo) and of grade 3 or 4 adverse events related to pembrolizumab or placebo (18.6% vs. 1.2%). No deaths were attributed to pembrolizumab therapy.ConclusionsAdjuvant pembrolizumab was associated with a significant and clinically meaningful improvement in overall survival, as compared with placebo, among participants with clear-cell renal-cell carcinoma at increased risk for recurrence after surgery. (Funded by Merck Sharp and Dohme, a subsidiary of Merck; KEYNOTE-564 ClinicalTrials.gov number, NCT03142334.
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Programmed death ligand-1 expression in adrenocortical carcinoma: an exploratory biomarker study
Background: Adrenocortical carcinoma (ACC) is a rare tumor in which prognostic factors are still not well established. Programmed Death Ligand-1 (PD-L1) expression in ACC and its association with clinico-pathological features and survival outcomes are unknown. Methods: Formalin-fixed paraffin-embedded (FFPE) specimens were obtained from 28 patients with ACC. PD-L1 expression was evaluated by immunohistochemistry (IHC) in both tumor cell membrane and tumor infiltrating mononuclear cells (TIMC). PD-L1 positivity on tumor cells was defined as ≥5% tumor cell membrane staining. TIMC were evaluated by IHC using a CD45 monoclonal antibody. For PD-L1 expression in TIMC, a combined score based on the extent of infiltrates and percentage of positive cells was developed. Any score greater that zero was considered PD-L1 positive. Baseline clinico-pathological characteristics and follow up data were retrospectively collected. Comparisons between PD-L1 expression and clinico-pathological features were evaluated using unpaired t-test and Fisher’s exact test. Kaplan-Meier method and log-rank test were used to assess association between PD-L1 expression and 5-year overall survival (OS). Results: Among 28 patients with surgically treated ACC, 3 (10.7%) were considered PD-L1 positive on tumor cell membrane. On the other hand, PD-L1 expression in TIMC was performed in 27 specimens and PD-L1 positive staining was observed in 19 (70.4%) patients. PD-L1 positivity in either tumor cell membrane or TIMC was not significantly associated with higher stage at diagnosis, higher tumor grade, excessive hormone secretion, or OS. Conclusions: PD-L1 expression can exist in ACC in both tumor cell membrane and TIMC with no relationship to clinico-pathologic parameters or survival. Electronic supplementary material The online version of this article (doi:10.1186/s40425-015-0047-3) contains supplementary material, which is available to authorized users
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