367 research outputs found

    Route planning for a fleet of electric vehicles with waiting times at charging stations

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    Singapore National Research Foundation Singapore under iCorp Lab @ University; Fujitsu Limite

    On non-local variational problems with lack of compactness related to non-linear optics

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    We give a simple proof of existence of solutions of the dispersion manage- ment and diffraction management equations for zero average dispersion, respectively diffraction. These solutions are found as maximizers of non-linear and non-local vari- ational problems which are invariant under a large non-compact group. Our proof of existence of maximizer is rather direct and avoids the use of Lions' concentration compactness argument or Ekeland's variational principle.Comment: 30 page

    Rethinking mobility of international university students during COVID-19 pandemic

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    Purpose – The purpose of the study is to examine the relationship between the COVID-19 pandemic and international student mobility from an alternative perspective and to reveal descriptive findings. Design/methodology/approach – This study follows qualitative research methodology. In accordance with the purpose of the study, the data were collected by the literature review and then it was analyzed by the descriptive analysis method. The effect of the COVID-19 pandemic on international student mobility and the relationships between these variables are explained by tables and classifications. Findings – According to the findings obtained, the restrictions in physical student mobility and shutdown are observed as the biggest challenges that occurred in higher education during the COVID-19. On a global scope, international student mobility has experienced a major break. Physical campus life is still on standby. Online higher education does not give any campus life as before. Students cannot benefit form city's or country's facilities when studying online at home country. The collaboration between university and business has been declined and this is even more discouraging for international students. The hybrid education model produced an intermediate solution in this period. On the other hand, the rise of online education has created new techniques for higher education. University students who cannot go abroad attend different countries lectures and education programs. But also a new challenge has come as the access of online platforms in under developing countries university students. Online education system also discussed in terms of creating inequality in higher education. Research limitations/implications – This study focused on student mobility and not focused about academic mobility. Practical implications – It is seen that the traditional higher education system has been adapted into online distance higher education system since COVID-19 crises began globally. On the other side, it is observed that most of studies have focused the effect of COVID-19 on university students based on the transition to online education. When considering the effect of pandemic process on the mobility of international students and higher education, the authors can suggest policy makers to develop new higher education protocols and teaching models supporting key issues (economic, social, health, education and equalization) in the long-term. Higher education institutes have been able to produce creative and innovative solutions for both education and communication during the pandemic process. Social implications – University students who cannot go abroad attend different countries lectures and education programs. But also a new challenge has come as the access of online platforms in under developing countries university students. Online education system also discussed in terms of creating inequality in higher education. Originality/value – This study provides a new perspective for international student mobility in the context of COVID-19 pandemic. This is an emerging issue for the literature. This study is original with its approach to the subject from a global perspective through reviewing the studies of different countries. This study points out key variables for determining the effect of COVID-19 on international student mobility for future studies. When employing quantitative research models, the current key variables can guide them

    Blastocystis: A mysterious member of the gut microbiome

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    Blastocystis is the most common gastrointestinal protist found in humans and animals. Although the clinical significance of Blastocystis remains unclear, the organism is increasingly being viewed as a commensal member of the gut microbiome. However, its impact on the microbiome is still being debated. It is unclear whether Blastocystis promotes a healthy gut and microbiome directly or whether it is more likely to colonize and persist in a healthy gut environment. In healthy people, Blastocystis is frequently associated with increased bacterial diversity and significant differences in the gut microbiome. Based on current knowledge, it is not possible to determine whether differences in the gut microbiome are the cause or result of Blastocystis colonization. Although it is possible that some aspects of this eukaryote’s role in the intestinal microbiome remain unknown and that its effects vary, possibly due to subtype and intra-subtype variations and immune modulation, more research is needed to characterize these mechanisms in greater detail. This review covers recent findings on the effects of Blastocystis in the gut microbiome and immune modulation, its impact on the microbiome in autoimmune diseases, whether Blastocystis has a role like bacteria in the gut–brain axis, and its relationship with probiotics

    Mammary tuberculosis – importance of recognition and differentiation from that of a breast malignancy: report of three cases and review of the literature

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    <p>Abstract</p> <p>Background</p> <p>While tuberculosis of the breast is an extremely uncommon entity seen in western populations, it accounts for up to 3% of all treatable breast lesions in developing countries.</p> <p>Case presentations</p> <p>We reviewed three female cases of mammary tuberculosis that were diagnosed and treated in Turkey during the same calendar year. All three patients presented with a painful breast mass. In all cases, fine needle aspiration was nondiagnostic for mammary tuberculosis. However, the diagnosis of mammary tuberculosis was confirmed by histopathologic evaluation at the time of open surgical biopsy. All three patients were treated with antituberculous therapy for six months. At the end of the treatment period, each patient appeared to be clinically and radiologically without evidence of residual disease.</p> <p>Conclusion</p> <p>The diagnosis of mammary tuberculosis rests on the appropriate clinical suspicion and the histopathologic findings of the breast lesion. Its recognition and differentiation from that of a breast malignancy is absolutely necessary. Antituberculous chemotherapy, initiated immediately upon diagnosis, forms the mainstay of treatment for mammary tuberculosis.</p

    Use and detailed metric properties of patient-reported outcome measures for rheumatoid arthritis: a systematic review covering two decades

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    Introduction The importance of patient-reported outcome measures (PROMs) for rheumatoid arthritis (RA) clinical studies has been recognised for many years. The current study aims to describe the RA PROMs used over the past 20 years, and their performance metrics, to underpin appropriate tool selection. Methods The study included a systematic search for PROMs that have been in use over the period 2000–2019, with detailed documentation of their psychometric properties, and a user-friendly presentation of the extensive evidence base. Results 125 PROMs were identified with psychometric evidence available. The domains of pain, fatigue, emotional functions, mobility, physical functioning and work dominated, with self-efficacy and coping as personal factors. Domains such as stiffness and sleep were poorly served. The most frequently used PROMs included the Health Assessment Questionnaire Disability Index (HAQ), the Short Form 36 (SF-36), the EuroQoL and the Modified HAQ which, between them, appeared in more than 3500 papers. Strong psychometric evidence was found for the HAQ, and the SF-36 Physical Functioning and Vitality (fatigue) domains. Otherwise, all domains except stiffness, sleep, education and health utility, had at least one PROM with moderate level of psychometric evidence. Conclusion There is a broad range of PROMs for measuring RA outcomes, but the quality of psychometric evidence varies widely. This work identifies gaps in key RA domains according to the biopsychosocial model

    An evaluation of three DoE-guided meta-heuristic-based solution methods for a three-echelon sustainable distribution network

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    This article evaluates the efficiency of three meta-heuristic optimiser (viz. MOGA-II, MOPSO and NSGA-II)-based solution methods for designing a sustainable three-echelon distribution network. The distribution network employs a bi-objective location-routing model. Due to the mathematically NP-hard nature of the model a multi-disciplinary optimisation commercial platform, modeFRONTIER®, is adopted to utilise the solution methods. The proposed Design of Experiment (DoE)-guided solution methods are of two phased that solve the NP-hard model to attain minimal total costs and total CO2 emission from transportation. Convergence of the optimisers are tested and compared. Ranking of the realistic results are examined using Pareto frontiers and the Technique for Order Preference by Similarity to Ideal Solution approach, followed by determination of the optimal transportation routes. A case of an Irish dairy processing industry’s three-echelon logistics network is considered to validate the solution methods. The results obtained through the proposed methods provide information on open/closed distribution centres (DCs), vehicle routing patterns connecting plants to DCs, open DCs to retailers and retailers to retailers, and number of trucks required in each route to transport the products. It is found that the DoE-guided NSGA-II optimiser based solution is more efficient when compared with the DoE-guided MOGA-II and MOPSO optimiser based solution methods in solving the bi-objective NP-hard three-echelon sustainable model. This efficient solution method enable managers to structure the physical distribution network on the demand side of a logistics network, minimising total cost and total CO2 emission from transportation while satisfying all operational constraints

    Environmental Education in Serbian Primary Schools: Challenges and Changes in Curriculum, Pedagogy, and Teacher Training

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    The protection of human health and the preservation of the environment are topics that form anintegral part of the primary school curriculum in Serbia. However, research studies have shown thatstudents do not have enough knowledge to contribute to the development of a healthy lifestyle andenvironmental awareness. The latest changes in school policy and curricula confirm that the relevanceof environmental education has been recognized, but changes in school practice are yet to come. Thisarticle discusses the challenges encountered in the implementation of the intended curriculum andoffers suggestions for changes to the curriculum, pedagogy, and teacher training in order to enhanceenvironmental educationThis is the peer-reviewd version of the artivle: Stanišić, Jelena, и Slavica Maksić. 2014. „Environmental Education in Serbian Primary Schools: Challenges and Changes in Curriculum, Pedagogy, and Teacher Training“. Journal of Environmental Education 45(2):118–31. doi: 10.1080/00958964.2013.829019.Related to published version: [ http://ipir.ipisr.org.rs/handle/123456789/240

    British Valued Life Activities Scale [British VLAs]

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    Background The Valued Life Activities Scale (VLAs) measures difficulty in daily activities and social participation. With various versions involving a different number of items, we have linguistically and culturally adopted the full VLAs (33-items) and psychometrically tested it in adults with rheumatic and musculoskeletal diseases in the United Kingdom. Methods Participants with Rheumatoid Arthritis, Ankylosing Spondylitis, Chronic Pain/ Fibromyalgia, Chronic Hand/ Upper Limb Conditions, Osteoarthritis, Systemic Lupus, Systemic Sclerosis and Primary Sjogren’s Syndrome were recruited from out-patient clinics in National Health Service Hospitals, General Practice and patient organisations in the UK. Phase1 involved linguistic and cultural adaptation: forward translation to British English; synthesis; expert panel review and cognitive debriefing interviews. In Phase2 participants completed postal questionnaires to assess internal construct validity using (i) Confirmatory Factor Analysis (CFA) (ii) Mokken scaling and (iii) Rasch model. Results Responders (n = 1544) had mean age of 59 years (SD13.3) and 77.2% women. A CFA failed to support a total score from the 33-items (Chi Square 3552:df 464: p < 0.0001). Mokken scaling indicated a strong non-parametric association between items. Fit to the Rasch model indicated that the VLAs was characterised by multidimensionality and item misfit, which may have been influenced by clusters of residual item correlations. An item banking approach resolved a 25-item calibrated set whose application could accommodate the ‘does not apply to me’ response option. Conclusions The UK version of the VLAs failed to satisfy classical and modern psychometric standards for complete item sets. However, as the scale is not usually applied in complete format, an item bank approach calibrated 25 items with fit to the Rasch model. Suitable Computer Adaptive Testing (CAT) software could implement the item set, giving patients the choice of whether an item applies to them, or not

    Effect of mixture proportions on the drying shrinkage and permeation properties of high strength concrete containing class F fly ash

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    Sustainability of concrete can be improved by using large volume of fly ash as a replacement of cement and by ensuring improved durability of concrete. Durability of concrete containing large volume of class F fly ash is dependent on the design of mixture proportions. This paper presents an experimental study on the effect of mixture proportions on the drying shrinkage and permeation properties of high strength concrete containing large volume local class F fly ash. Concrete mixtures were designed with and without adjustments in the water to binder ratio (w/b) and the total binder content to take into account the incorporation of fly ash up to 40% of total binder. Concretes, in which the mixture proportions were adjusted for fly ash inclusion achieved equivalent strength of the control concrete and showed enhanced properties of drying shrinkage, sorptivity, water permeability and chloride penetration as compared to the control concrete. The improvement of durability properties was less significant when no adjustments were made to the w/b ratio and total binder content. The results show the necessity of the adjustments in mixture proportions of concrete to achieve improved durability properties when using class F fly ash as a cement replacement
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