Search results for: hybrid attention mechanism

Authors: Emmanuel Pedler, Elena Raevskikh, Maxime Jaffré

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Can the cultural geography of European cities be durably managed by European policies? To answer this question, two hypotheses can be proposed. (1) Either European cultural policies are able to erase cultural inequalities between the territories through the creation of new areas of cultural attractiveness in each beneficiary neighborhood, city or country. Or, (2) each European region historically rooted in a number of endogenous socio-historical, political or demographic factors is not receptive to exogenous political influences. Thus, the cultural attractiveness of a territory is difficult to measure and to impact by top-down policies in the long term. How do these two logics - European and local - interact and contribute to the emergence of a valued, popular sense of a common European cultural identity? Does this constant interaction between historical backgrounds and new political concepts encourage a positive identification with the European project? The European cultural policy programs, such as ECC (European Capital of Culture), seek to develop new forms of civic cohesion through inclusive and participative cultural events. The cultural assets of a city elected ‘ECC’ are mobilized to attract a wide range of new audiences, including populations poorly integrated into local cultural life – and consequently distant from pre-existing cultural offers. In the current context of increasingly heterogeneous individual perceptions of Europe, the ECC program aims to promote cultural forms and institutions that should accelerate both territorial and cross-border European cohesion. The new cultural consumption pattern is conceived to stimulate integration and mobility, but also to create a legitimate and transnational ideal European citizen type. Our comparative research confronts contrasting cases of ‘European Capitals of Culture’ from the south and from the north of Europe, cities recently concerned by the ECC political mechanism and cities that were elected ECC in the past, multi-centered cultural models vs. highly centralized cultural models. We aim to explore the impacts of European policies on the urban cultural geography, but also to understand the current obstacles for its efficient implementation.

Keywords: urbanism, cultural policies, cultural institutions, european cultural capitals, heritage industries, exclusion effects

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Authors: Nausheen Irshad

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Human-wildlife conflict (HWC) exists in both developed and developing countries though it is more serious in developing nations. Knowledge of species ecology and species sensitivity to anthropogenic pressures is an important prerequisite for conservation/management. Therefore, three districts (Poonch, Bagh, and Muzaffarabad) of Azad Jammu and Kashmir were selected to highlight the wildlife hunting practices from January 2015 to November 2018. The study area was thoroughly explored to recover dead animals. Moreover, the local community was investigated (questionnaire survey) to catch on motives of killing. The results showed HWC mainly arises due to feeding habits of wild animals as some are frugivorous (small Indian civet and small Kashmir flying squirrel) who damaged human cultivated fruit trees. Besides, Indian crested porcupine and wild boar act as serious crop pests. The feeding upon domestic animals (common leopard) and poultry (Asiatic Jackal and Red fox) were also reported as factors of conflict. Hence numerous wild animals and birds (N=120) were found killed by natives in revenge. Despite protected status in Pakistan, the killed mammals belonged to categories of critically endangered (Panthera pardus) and near threatened (Viverricula indica) species. The important birds include critically endangered (Falco peregrines) and endangered (Lophura leucomelanos) species. It was found that mammals were primarily killed due to HWC (60%) followed by recreation (20%) and trade (15%) Whereas, the foremost hunting reasons for birds are recreation (50%), food (25%) and trade (25%). The drastic hunting/killing of the species needs our immediate attention. This unwarranted killing must be stopped forthwith otherwise these animals become extinct.

Keywords: Azad Jammu and Kashmir, anthropogenic pressures, endangered species, human-wildlife conflicts

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Authors: Saeed Pourhassan, Nastaran Maghbouli

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Statement of the problem: The relationship between obesity and cardiovascular diseases has been studied widely(1). The distribution of fat tissue gained attention in relation to cardiovascular risk factors during lang-time research (2). American College of Cardiology/American Heart Association (ACC/AHA) is widely and the most reliable tool to be used as a cardiovascular risk (CVR) assessment tool(3). This study aimed to determine which anthropometric index is better in discrimination of high CVR patients from low risks using ACC/AHA score in addition to finding the best index as a CVR predictor among both genders in different races and countries. Methodology & theoretical orientation: The literature in PubMed, Scopus, Embase, Web of Science, and Google Scholar were searched by two independent investigators using the keywords "anthropometric indices," "cardiovascular risk," and "obesity." The search strategy was limited to studies published prior to Jan 2022 as full-texts in the English language. Studies using ACC/AHA risk assessment tool as CVR and those consisted at least 2 anthropometric indices (ancient ones and novel ones) are included. Study characteristics and data were extracted. The relative risks were pooled with the use of the random-effect model. Analysis was repeated in subgroups. Findings: Pooled relative risk for 7 studies with 16,348 participants were 1.56 (1.35-1.72) for BMI, 1.67(1.36-1.83) for WC [waist circumference], 1.72 (1.54-1.89) for WHR [waist-to-hip ratio], 1.60 (1.44-1.78) for WHtR [waist-to-height ratio], 1.61 (1.37-1.82) for ABSI [A body shape index] and 1.63 (1.32-1.89) for CI [Conicity index]. Considering gender, WC among females and WHR among men gained the highest RR. The heterogeneity of studies was moderate (α²: 56%), which was not decreased by subgroup analysis. Some indices such as VAI and LAP were evaluated just in one study. Conclusion & significance: This meta-analysis showed WHR could predict CVR better in comparison to BMI or WHtR. Some new indices like CI and ABSI are less accurate than WHR and WC. Among women, WC seems to be a better choice to predict cardiovascular disease risk.

Keywords: obesity, cardiovascular disease, risk assessment, anthropometric indices

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Authors: J. Adeppa, S. Samanta, O. K. Raina

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Fasciolosis is a widespread economically important parasitic infection throughout the world caused by Fasciola hepatica and F. gigantica. In order to identify novel immunogen conferring significant protection against fasciolosis, currently, research has been focused on the defined antigens viz. glutathione S-transferase, fatty acid binding protein, cathepsin-L, fluke hemoglobin, paramyosin, myosin and F. hepatica- Kunitz Type Molecule. Among various antigens, GST which plays a crucial role in detoxification processes, i.e. phase II defense mechanism of this parasite, has a unique position as a novel vaccine candidate and a drug target in the control of this disease. For producing the antigens in large quantities and their purification to complete homogeneity, the recombinant DNA technology has become an important tool to achieve this milestone. RT- PCR was carried out using F. gigantica total RNA as template, and an amplicon of 657 bp GST gene was obtained. TA cloning vector was used for cloning of this gene, and the presence of insert was confirmed by blue-white selection for recombinant colonies. Sequence analysis of the present isolate showed 99.1% sequence homology with the published sequence of the F. gigantica GST gene of cattle origin (accession no. AF112657), with six nucleotide changes at 72, 74, 423, 513, 549 and 627th bp found in the present isolate, causing an overall change of 4 amino acids. The 657 bp GST gene was cloned at BamH1 and HindIII restriction sites of the prokaryotic expression vector pPROEXHTb in frame with six histidine residues and expressed in E. coli DH5α. Recombinant protein was purified from the bacterial lysate under non-denaturing conditions by the process of sonication after lysozyme treatment and subjecting the soluble fraction of the bacterial lysate to Ni-NTA affinity chromatography. Western blotting with rabbit hyper-immune serum showed immuno-reactivity with 25 kDa recombinant GST. Recombinant protein detected F. gigantica experimental as well as field infection in buffaloes by dot-ELISA. However, cross-reactivity studies on Fasciola gigantica GST antigen are needed to evaluate the utility of this protein in the serodiagnosis of fasciolosis.

Keywords: fasciola gigantic, fasciola hepatica, GST, RT- PCR

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Authors: Saila Tykkyläinen

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The purpose of this study is to pave the way for more focused accumulation of knowledge on social enterprise growth. The body of research touching upon the phenomenon is somewhat fragmented. In order to make an effort to create a solid common ground, this study draws from the theoretical starting points and guidelines developed within small firm growth research. By analyzing their use in social enterprise growth literature, the study offers insights on whether the proven theories and concepts from small firm context could be more systematically applied when investigating growth of social enterprises. Towards this end, the main findings from social enterprise growth research are classified under the three research streams on growth. One of them focuses on factors of growth, another investigates growth as a process and the third is interested in outcomes of growth. During the analysis, special attention is paid on exploring how social mission of the company and the pursuit of augmenting its social impact are dealt within those lines of research. The next step is to scrutinize and discuss some of the central building blocks of growth research, namely the unit of analysis, conceptualization of a firm and operationalizing growth, in relation to social enterprise studies. It appears that the social enterprise growth literature stresses the significance of 'social' both as a main driver and principle outcome of growth. As for the growth process, this emphasis is manifested by special interest in strategies and models tailored to disseminate social impact beyond organizational limits. Consequently, this study promotes more frequent use of business activity as a unit of analysis in the social enterprise context. Most of the times, it is their products, services or programs with which social enterprises and entrepreneurs aim to create the impact. Thus the focus should be placed on activities rather than on organizations. The study also seeks to contribute back to the small firm growth research. Even though the recommendation to think of business activities as an option for unit of analysis stems from there, it is all too rarely used. Social entrepreneurship makes a good case for testing and developing the approach further.

Keywords: conceptual study, growth, scaling, social enterprise

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Authors: R. R. Billones, N. Lukkahatai, L. N. Saligan

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Mindfulness based interventions (MBIs) have been used in medically unexplained symptoms (MUS). This systematic review describes the literature investigating the general effect of MBIs on MUS and identifies the effects of specific MBIs on specific MUS conditions. The preferred reporting items for systematic reviews and meta-analysis guidelines (PRISMA) and the modified Oxford quality scoring system (JADAD) were applied to the review, yielding an initial 1,556 articles. The search engines included PubMed, ScienceDirect, Web of Science, Scopus, EMBASE, and PsychINFO using the search terms: mindfulness, or mediations, or mindful or MBCT or MBSR and medically unexplained symptoms or MUS or fibromyalgia or FMS. A total of 24 articles were included in the final systematic review. MBIs showed large effects on socialization skills for chronic fatigue syndrome (d=0.65), anger in fibromyalgia (d=0.61), improvement of somatic symptoms (d=1.6) and sleep (d=1.12) for painful conditions, physical health for chronic back pain (d=0.51), and disease intensity for irritable bowel disease/syndrome (d=1.13). A manualized MBI that applies the four fundamental elements present in all types of interventions were critical to efficacy. These elements were psycho-education sessions specific to better understand the medical symptoms, the practice of awareness, the non-judgmental observance of the experience at the moment, and the compassion to ones’ self. The effectiveness of different mindfulness interventions necessitates giving attention to improve the gaps that were identified related to home-based practice monitoring, competency training of mindfulness teachers, and sound psychometric properties to measure the mindfulness practice.

Keywords: mindfulness-based interventions, medically unexplained symptoms, mindfulness-based cognitive therapy, mindfulness-based stress reduction, fibromyalgia, irritable bowel syndrome

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Authors: Rayhana Begum, Manju Sharma

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Careya arborea Roxb. belongs to the Lecythidaceae family, is traditionally used in tumors, anthelmintic, bronchitis, epileptic fits, astringents, inflammation, an antidote to snake-venom, skin disease, diarrhea, dysentery with bloody stools, dyspepsia, ulcer, toothache, and ear pain. The present study was focused on investigating the anti-arthritic effect of coumaroyl lupendioic acid, a new lupane-type triterpene from Careya arborea stem bark in the chronic inflammatory model and further assessing its possible mechanism on the modulation of inflammatory biomarkers. Arthritis was induced by injecting 0.1 ml of Complete Freund’s Adjuvant (5 mg/ml of heat killed Mycobacterium tuberculosis) into the subplantar region of the left hind paw. Treatment with coumaroyl lupendioic acid (10 and 20 mg/kg, p.o.) and reference drugs (indomethacin and dexamethasone at the dose of 5 mg/kg, p.o.) were started on the day of induction and continued up to 28 days. The progression of arthritis was evaluated by measuring paw volume, tibio tarsal joint diameters, and arthritic index. The effect of coumaroyl lupendioic acid (CLA) on the production PGE₂, NO, MPO, NF-κB, TNF-α, IL-1β, and IL-6 on serum level as well as inflamed paw tissue were also assessed. In addition, ankle joints and spleen were collected and prepared for histological examination. CLA in inflamed rats resulted in significant amelioration of paw edema, tibio-tarsal joint swelling and arthritic score as compared to CFA control group. The results indicated that CLA treated groups markedly decreased the levels of inflammatory mediators (PGE₂, NO, MPO and NF-κB levels) and down-regulated the production of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) in paw tissue homogenates as well as in serum. However, the more pronounced effect was observed in the inflamed paw tissue homogenates. CLA also revealed a protective effect to the tibio-tarsal joint cartilage and spleen. These results suggest that coumaroyl lupendioic acid inhibits inflammation may be through the suppression of the cascade of proinflammatory mediators via the down-regulation of NF-ҡB.

Keywords: complete Freund’s adjuvant , Coumaroyl lupendioic acid, pro-inflammatory cytokines, prostaglandin E2

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Authors: Tadewos Awugchew Wudineh

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Health and safety issues have always been a major problem and concern in the building construction industry. The health and safety regulations are stated to eliminate the potential hazards and to reduce the consequential risks. However, the importance of the regulations seems to be overlooked in building construction sites of Hawassa City. Accordingly, many companies don’t follow the regulations as construction workers are more likely to be injured and killed by construction accident than any other type of employment. This paper aimed to identify factors that affect the implementation of construction health and safety regulations, their effects and mitigation measures in building construction project sites of Hawassa City. To reach this objective, a review of literature as well as the Ethiopian construction health and safety regulations have been undertaken. Mainly a five-point Likert scale questionnaire was distributed, and statistical analysis was used to summarize, interpret the data, and to find the significances of the responses. In addition, interviews were carried out. Accordingly, the findings indicate that the top factors which affect the implementation of CHS regulations are, availability and development of a clear health and safety policy, health and safety inspections by top management, conducting health and safety training and orientation, provision of healthy and safe working environment and employment of trained safety officers. The study revealed that implementation or non-implementation of CHS regulations have effects on the worker’s productivity, job satisfaction, rate of accidents, and cost greatly. Thus, the suggestion to minimize the impact on worker’s job performance are, developing of a clear health and safety policy, management commitment towards implementation of health and safety regulations, health and safety education and training and conducting regular health and safety inspections. It was concluded from the study that good implementation of health and safety regulations are the results from administrative and management commitment which calls for more attention to be paid to improve the implementation of CHS regulations in building construction sites of Hawassa City.

Keywords: construction health and safety regulations, effects, factors, mitigation

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Authors: K. Anas, M. Selvakumar, Samson David, R. R. Babu, S. Chattopadhyay

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The dynamic deformation of a visco elastic material can cause heat generation. This heat generation is aspect energy dissipation. The present work investigates the contribution of various factors like; elastomer structure, cross link type and density, filler networking, reinforcement potential and temperature at energy dissipation mechanism. The influences of these elements are investigated using very high frequency analyzer (VHF ) and dynamical mechanical analysis(DMA).VHF follows transmissibility and vibration isolation principle whereas DMA works on dynamical mechanical deformation principle. VHF analysis of different types of elastomers reveals that elastomer can act as a transmitter or damper of energy depending on the applied frequency ratio (ω/ωn). Dynamic modulus (G') of low damping rubbers like natural rubber does not varies rapidly with frequency but vice-versa for high damping rubber like butyl rubber (IIR). VHF analysis also depicts that polysulfidic linkages has high damping ratio (ζ) than mono sulfidic linkages due to its dissipative nature. At comparable cross link density, mono sulfidic linkages shows higher glass transition temperature (Tg) than poly sulfidic linkages. The intensity and location of loss modulus (G'') peak of different types of carbon black filled natural rubber compounds suggests that segmental relaxation at glass transition temperature (Tg) is seldom affected by filler particles, but the filler networks can influence the cross link density by absorbing the curatives. The filler network breaking and reformation during a dynamic strain is a thermally activated process. Thus, stronger aggregates are highly dissipative in nature. Measurements indicate that at lower temperature regimes polymeric chain friction is highly dissipative in nature.

Keywords: damping ratio, natural frequency, crosslinking density, segmental motion, surface activity, dissipative, polymeric chain friction

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Authors: Mustafa Durmuş, Yesim Ozogul, Esra Balıkcı, Saadet Gokdoğan, Fatih Ozogul, Ali Rıza Köşker, İlknur Yuvka

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Food scientists and researchers have paid attention to develop new ways for improving the nutritional value of foods. The application of nanotechnology techniques to the food industry may allow the modification of food texture, taste, sensory attributes, coloring strength, processability, and stability during shelf life of products. In this research, the effects of nanoemulsions based on commercial oils for vacuum-packed sea bass fillets stored at 2±2°C were investigated in terms of the sensory, chemical (total volatile basic nitrogen (TVB-N), thiobarbituric acid (TBA), peroxide value (PV) and free fatty acids (FFA), pH, water holding capacity (WHC)) and microbiological qualities (total anaerobic bacteria and total lactic acid bacteria). Physical properties of emulsions (viscosity, the particle size of droplet, thermodynamic stability, refractive index, and surface tension) were determined. Nanoemulsion preparation method was based on high energy principle, with ultrasonic homojenizator. Sensory analyses of raw fish showed that the demerit points of the control group were found higher than those of treated groups. The sensory score (odour, taste and texture) of the cooked fillets decreased with storage time, especially in the control. Results obtained from chemical and microbiological analyses also showed that nanoemulsions significantly (p<0.05) decreased the values of biochemical parameters and growth of bacteria during storage period, thus improving quality of vacuum-packed sea bass.

Keywords: quality parameters, nanoemulsion, sea bass, shelf life, vacuum packing

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Authors: Shih-Ping Liu, Cheng-Hsuan Chang, Yu-Chuen Huang, Shih-Yin Chen, Woei-Cherng Shyu

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Embryonic stem cells (ES) and induced pluripotnet stem cells (iPS) are both pluripotent stem cells. For mouse stem cells culture technology, leukemia inhibitory factor (LIF) was used to maintain the pluripotency of stem cells in vitro. However, LIF is an expensive reagent. The goal of this study was to find out a pure compound extracted from Chinese herbal medicine that could maintain stem cells pluripotency to replace LIF and improve the iPS generation efficiency. From 20 candidates traditional Chinese medicine we found that Cordycepsmilitaris triggered the up-regulation of stem cells activating genes (Oct4 and Sox2) expression levels in MEF cells. Cordycepin, a major active component of Cordycepsmilitaris, also could up-regulate Oct4 and Sox2 gene expression. Furthermore, we used ES and iPS cells and treated them with different concentrations of Cordycepin (replaced LIF in the culture medium) to test whether it was useful to maintain the pluripotency. The results showed higher expression levels of several stem cells markers in 10 μM Cordycepin-treated ES and iPS cells compared to controls that did not contain LIF, including alkaline phosphatase, SSEA1, and Nanog. Embryonic body formation and differentiation confirmed that 10 μM Cordycepin-containing medium was capable to maintain stem cells pluripotency after four times passages. For mechanism analysis, microarray analysis indicated extracellular matrix and Jak/Stat signaling pathway as the top two deregulated pathways. In ECM pathway, we determined that the integrin αVβ5 expression levels and phosphorylated Src levels increased after Cordycepin treatment. In addition, the phosphorylated Jak2 and phosphorylated Sat3 protein levels were increased after Cordycepin treatment and suppressed with the Jak2 inhibitor, AG490. The expression of cytokines associated with Jak2/Stat3 signaling pathway were also up-regulated by Q-PCR and ELISA assay. Lastly, we used Oct4-GFP MEF cells to test iPS generation efficiency following Cordycepin treatment. We observed that 10 Μm Cordycepin significantly increased the iPS generation efficiency in day 21. In conclusion, we demonstrated Cordycepin could maintain the pluripotency of stem cells through both of ECM and Jak2/Stat3 signaling pathway and improved iPS generation efficiency.

Keywords: cordycepin, iPS cells, Jak2/Stat3 signaling pathway, molecular biology

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Authors: Hongtao Zhu, Dezhi Sun

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Nitrogen and phosphorus are essential nutrients for biomass growth. But excessive nitrogen and phosphorus can contribute to accelerated eutrophication of lakes and rivers. Constructed wetland is an efficient and eco-friendly wastewater treatment technology with low operating cost and low-energy consumption. Because of high affinity with ammonium ion, zeolite, as a common substrate, is applied in constructed wetlands worldwide. Another substrate seen commonly for constructed wetlands is steel slag, which has high contents of Ca, Al, or Fe, and possesses a strong affinity with phosphate. Due to the excellent ammonium removal ability of zeolite and phosphate removal ability of steel slag, they were considered to be combined in the substrate bed of a constructed wetland in order to enhance the simultaneous removal efficiencies of nitrogen and phosphorus. In our early tests, zeolite and steel slag were combined with each other in order to simultaneously achieve a high removal efficiency of ammonium-nitrogen and phosphate-phosphorus. However, compared with the results when only zeolite was used, the removal efficiency of ammonia was sharply decreased when zeolite and steel slag were used together. The main objective of this study was to establish an overview of the interaction of steel slag and zeolite on ammonium nitrogen removal. The CaO dissolution from slag, as well as the effects of influencing parameters (i.e. pH and Ca2+ concentration) on the ammonium adsorption onto zeolite, was systematically studied. Modeling results of Ca2+ and OH- release from slag indicated that pseudo-second order reaction had a better fitness than pseudo-first order reaction. Changing pH value from 7 to 12 would result in a drastic reduction of the ammonium adsorption capacity on zeolite, from the peak at pH7. High Ca2+ concentration in solution could also inhibit the adsorption of ammonium onto zeolite. The mechanism for steel slag inhibiting the ammonium adsorption capacity of zeolite includes: on one hand, OH- released from steel slag can react with ammonium ions to produce molecular form ammonia (NH3∙H2O), which would cause the dissociation of NH4+ from zeolite. On the other hand, Ca2+ could replace the NH4+ ions to adhere onto the surface of zeolite. An innovative substrate filling configuration that zeolite and steel slag are placed sequentially was proposed to eliminate the disadvantageous effects of steel slag. Experimental results showed that the novel filling configuration was superior to the other two contrast filling configurations in terms of ammonium removal.

Keywords: ammonium nitrogen, constructed wetlands, steel slag, zeolite

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Authors: Salima Taleb, Kafila Boulaba, Ahlem Yousfi, Nada Taleb, Difallah Basma

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Introduction: Obesity is recognized as a cardiovascular risk factor. It is associated with cardio-metabolic diseases. Its prevalence is increasing significantly in both rich and poor countries. However, there are obese people who have no metabolic disturbance. So we think obesity is not always a risk factor for an abnormal metabolic profile that increases the risk of cardiometabolic problems. However, there is no definition that allows us to identify the individual group Metabolically Healthy but Obese (MHO). Objective: The objective of this study is to evaluate the relationship between MHO and some factors associated with it. Methods: A longitudinal study is a prospective cohort study of 600 participants aged ≥18 years. Metabolic status was assessed by the following parameters: blood pressure, fasting glucose, total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides. Body Mass Index (BMI) was calculated as weight (in kg) divided by height (m2), BMI = Weight/(Height)². According to the BMI value, our population was divided into four groups: underweight subjects with BMI <18.5 kg/m2, normal weight subjects with BMI = 18.5–24.9 kg/m², overweight subjects with BMI=25–29.9 kg/m², and obese subjects who have (BMI ≥ 30 kg/m²). A value of P < 0.05 was considered significant. Statistical processing was done using the SPSS 25 software. Results: During this study, 194 (32.33%) were identified as MHO among 416 (37%) obese individuals. The prevalence of the metabolically unhealthy phenotype among normal-weight individuals was (13.83%) vs. (37%) in obese individuals. Compared with metabolically healthy normal-weight individuals (10.93%), the prevalence of diabetes was (30.60%) in MHO, (20.59%) in metabolically unhealthy normal weight, and (52.29%) for metabolically unhealthy obese (p = 0.032). Blood pressure was significantly higher in MHO individuals than in metabolically healthy normal-weight individuals and in metabolically unhealthy obese than in metabolically unhealthy normal weight (P < 0.0001). Familial coronary artery disease does not appear to have an effect on the metabolic status of obese and normal-weight patients (P = 0.544). However, waist circumference appears to have an effect on the metabolic status of individuals (P < 0.0001). Conclusion: This study showed a high prevalence of metabolic profile disruption in normal-weight subjects and a high rate of overweight and/or obese people who are metabolically healthy. To understand the physiological mechanism related to these metabolic statuses, a thorough study is needed.

Keywords: metabolically health, obesity, factors associated, cardiovascular diseases

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Authors: Chen Chuanzhi, Guo Yunyun

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The large linear array feeding parabolic cylindrical antenna of the satellite has the ability of large-area line focusing, multi-directional beam clusters simultaneously in a certain azimuth plane and elevation plane, corresponding quickly to different orientations and different directions in a wide frequency range, dual aiming of frequency and direction, and combining space power. Therefore, the large-diameter parabolic cylindrical antenna has become one of the new development directions of spaceborne antennas. Limited by the size of the rocked fairing, the large-diameter spaceborne antenna is required to be small mass and have a deployment function. After being orbited, the antenna can be deployed by expanding and be stabilized. However, few types of structures can be used to construct large cylindrical shell structures in existing structures, which greatly limits the development and application of such antennas. Aiming at high structural efficiency, the geometrical characteristics of parabolic cylinders and mechanism topological mapping law to the expandable truss are studied, and the basic configuration of deployable truss with cylindrical shell is structured. Then a modular truss parabolic cylindrical antenna is designed in this paper. The antenna has the characteristics of stable structure, high precision of reflecting surface formation, controllable motion process, high storage rate, and lightweight, etc. On the basis of the overall configuration comprehensive theory and optimization method, the structural stiffness of the modular truss parabolic cylindrical antenna is improved. And the bearing density and impact resistance of support structure are improved based on the internal tension optimal distribution method of reflector forming. Finally, a truss-type cylindrical deployable support structure with high constriction-deployment ratio, high stiffness, controllable deployment, and low mass is successfully developed, laying the foundation for the application of large-diameter parabolic cylindrical antennas in satellite antennas.

Keywords: linear array feed antenna, truss type, parabolic cylindrical antenna, spaceborne antenna

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Authors: Ann Dashwood

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Using Standard Australian English with confidence is a cultural expectation of parents of primary school aged children who want to engage effectively with their children’s teachers and school administration. That confidence in support of their children’s learning at school is seldom experienced by parents whose first language is not English. Sharing language with competence in an intercultural environment is the common denominator for meaningful communication and engagement to occur in a school community. Experience in relevant, interactive sessions is known to enhance engagement and participation. The purpose of this paper is to identify a pedagogy for parents otherwise isolated from daily use of functional Australian cultural language learned to engage effectively in their children’s learning at school. The outcomes measure parents’ intercultural engagement with classroom teachers and attention to the school’s administrative procedures using quantitative and qualitative methods. A principled communicative task-based language learning approach, combined with intercultural communication strategies provide the theoretical base for intensive English inquiry-based learning and engagement. The quantitative analysis examines data samples collected by classroom teachers and administrators and parents’ writing samples. Interviews and observations qualitatively inform the study. Currently, significant numbers of projects are active in community centers and schools to enhance English language knowledge of parents from Language Backgrounds Other Than English (LBOTE). The study is significant to explore the effects of an intensive English pedagogy with parents of varied English language backgrounds, by targeting inquiry-based language use for social interactions in the school and wider community, specific engagement and cultural interaction with teachers and school activities and procedures.

Keywords: engagement, intercultural communication, language teaching pedagogy, LBOTE, school community

Procedia PDF Downloads 118

Authors: Karim Ahmed

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The purpose of this study was to investigate how factoring the impact of natural disasters beyond flooding would affect managed retreat policy eligibility in the United States. For the study design, a correlation analysis method compared weighted measures of flooding and other natural disasters (e.g., wildfires, tornadoes, heatwaves, etc.) to CBSA Populated areas, the prevalence of cropland, and relative poverty on a county level. The study found that the vast majority of CBSAs eligible for managed retreat programs under a policy inclusive of non-flooding events would have already been covered by flood-only managed retreat policies. However, it is noteworthy that a majority of those counties that are not covered by a flood-only managed retreat policy have high rates of poverty and are either heavily populated and/or agriculturally active. The correlation is particularly strong between counties that are subject to multiple natural hazards and those that have both high rates of relative poverty and cropland prevalence. There is currently no managed retreat policy for agricultural land in the United States despite the environmental implications and food supply chain vulnerabilities related to at-risk cropland. The findings of this study suggest both that such a policy should be created and, when it is, that special attention should be paid to non-flood natural disasters affecting agricultural areas. These findings also reveal that, while current flood-based policies in the United States serve many areas that do need access to managed retreat funding and implementation, other vulnerable areas are overlooked by this approach. These areas are often deeply impoverished and are therefore particularly vulnerable to natural disaster; if and when those disasters do occur, these areas are often less financially prepared to recover or retreat from the disaster’s advance and, due to the limitations of the current policies discussed above, are less able to take the precautionary measures necessary to mitigate their risk.

Keywords: flood, hazard, land use, managed retreat, wildfire

Procedia PDF Downloads 119

Authors: Liang Wang, Wei Zhang

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Nowadays, sustainable development has increasingly become an important research topic of engineering education. Existing research on Engineering Education for Sustainable Development (EESD) has highlighted the importance of perceptions for ethical responsibility to address sustainable development in practice. However, whether and how the professional engineering experience affects those perceptions has not been proved, especially in a Chinese context. Our study fills this gap by investigating the perceptions bias of EESD between experienced engineers and engineering students. We specifically examined what EESD means for experienced engineers and engineering students using a triple-dimensional model to understand if there are obvious differences between the two groups. Our goal is to make the benefits of these experiences more accessible in school context. The data (n=438) came from a questionnaire created and adapted from previously published studies containing 288 students from mechanical or civil engineering and 150 civil engineers with rich working experience, and the questionnaire was distributed during Fall 2020. T-test was used to find the difference in different dimensions between the two groups. The statistical results show that there is a significant difference in the perceptions of EESD between experienced engineers and inexperienced engineering students in China. Experienced engineers tend to consider sustainable development from ecological, economic, and social perspectives, while engineering students' answers focus more on ecology and ignore economic and social dimensions to some extend. The findings provide empirical evidence that professional experience is helpful to cultivate the cognition and ability of sustainable development in engineering education. The results of this work indicate that more practical content should be added to engineering education to promote sustainable development. In addition, for the design of engineering courses and professional practice systems for sustainable development, we should not only pay attention to the ecological aspects but also emphasize the coordination of ecological, economic, and socially sustainable development (e.g., engineer's ethical responsibility).

Keywords: engineering education, sustainable development, experienced engineers, engineering students

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Authors: Mei-Ling Chan, Jin-Ming Wu, Konstantin V. Kudryavtsev, Jih-Hwa Guh

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Prostate cancer is one of the most common malignant disease in men. KUD983 is an enantiomerically pure β-dipeptide derivative, which may have anti-cancer effects. In the present study, KUD983 exhibits powerful activity against hormone-refractory prostate cancer (HRPC) PC-3 and DU145 cells. The IC50 values of KUD983 in PC-3 and DU145 cells are 0.56±0.07M and 0.50±0.04 M respectively. KUD983 induced G1 arrest of the cell cycle and subsequent apoptosis associated with the down-regulation of several related proteins including cyclin D1, cyclin E and Cdk4, and the de-phosphorylation of RB. The protein expressions of nuclear and total c-Myc protein, which was able to regulate the expression of both cyclin D1 and cyclin E, were significantly suppressed by KUD983. Phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) is an important signaling pathway that influences the energy metabolism, cell cycle, proliferation, survival and apoptosis of cells, and is associated with numerous other signaling pathways. The Western Blot data revealed that KUD983 inhibited PI3K/Akt and mTOR/p70S6K/4E-BP1 pathways. The transient transfection of constitutively active myristylated Akt (myr-Akt) cDNA significantly reversed KUD983-induced caspase activation but did not abolish the suppression of mTOR/p70S6K/4E-BP1 signaling cascade indicating the presence of both Akt-dependent and -independent pathways. Moreover, KUD983-induced effect was collaborated with the down-regulation of anti-apoptotic Bcl-2 members (e.g., Bcl-2, and Mcl-1) and IAP family members (e.g., survivin). Furthermore, KUD983 induced autophagic cell death using confocal microscopic examination, investigating the level of conversion of LC3-I to LC3-II and flow cytometric detection of AVO-positive cells. Taken together, the data suggest that KUD983 is an anticancer β-dipeptide against HRPCs through the inhibition of cell proliferation and induction of apoptotic and autophagic cell death. The suppression of signaling pathways mediated by c-Myc, PI3K/Akt and mTOR/p70S6K/4E-BP1 and the collaboration with down-regulation of Mcl-1 and survivin may indicate the mechanism of KUD983 against HRPC.

Keywords: β-dipeptide, hormone-refractory prostate cancer, mTOR, PI3K/Akt

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Authors: Christoph Ostermair

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We deal with the effect of correlation between prospects on human decision making under uncertainty as proposed by the comparatively new and promising model of “salience theory of choice under risk”. In this regard, we show that the theory entails the prediction that the inconsistency of choices, known as the Allais paradox, should not be an issue in the context of “real-life decision making”, which typically corresponds to situations of subjective uncertainty. The Allais paradox, probably the best-known anomaly regarding expected utility theory, would then essentially have no practical relevance. If, however, empiricism contradicts this prediction, salience theory might suffer a serious setback. Explanations of the model for variable human choice behavior are mostly the result of a particular mechanism that does not come to play under perfect correlation. Hence, if it turns out that correlation between prospects – as typically found in real-world applications – does not influence human decision making in the expected way, this might to a large extent cost the theory its explanatory power. The empirical literature regarding the Allais paradox under subjective uncertainty is so far rather moderate. Beyond that, the results are hard to maintain as an argument, as the presentation formats commonly employed, supposably have generated so-called event-splitting effects, thereby distorting subjects’ choice behavior. In our own incentivized experimental study, we control for such effects by means of two different choice settings. We find significant event-splitting effects in both settings, thereby supporting the suspicion that the so far existing empirical results related to Allais paradoxes under subjective uncertainty may not be able to answer the question at hand. Nevertheless, we find that the basic tendency behind the Allais paradox, which is a particular switch of the preference relation due to a modified common consequence, shared by two prospects, is still existent both under an event-splitting and a coalesced presentation format. Yet, the modal choice pattern is in line with the prediction of salience theory. As a consequence, the effect of correlation, as proposed by the model, might - if anything - only weaken the systematic choice pattern behind the Allais paradox.

Keywords: Allais paradox, common consequence effect, models of decision making under risk and uncertainty, salience theory

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Authors: Moksha Singh

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The proponents of deinstitutionalization, including Goffman and others, in their works, have regarded institutions (orphanages to be specific) as regulated social arrangements that negatively impinge upon a resident’s development. They, therefore, propose alternative forms of care. However, even after five decades of this critique institutionalization remains the only hope for children with social, physical and mental disabilities in larger parts of the developing world such as the conflict affected state of Jammu and Kashmir in India. This paper is based on the experiences of children who lost their parents to insurgency and counter-insurgency operations and the rehabilitation process. This study is qualitative in nature and adopts descriptive-cum-exploratory research design. Using theoretical sampling, six orphanages and thirty one child residents who lost their parent(s) in the course of the armed conflict in the state of Jammu and Kashmir in India were studied in the year 2009-2010. It included interviews, observation, life histories and introspective accounts of the orphans and the management. The results were drawn through the qualitative examination, understanding, and interpretation of the primary and secondary data. The findings suggested that rehabilitation of these conflict-affected children is taking place mainly through residential child care facilities run by non-governmental bodies. Alternative forms of rehabilitation are not functional in the state because of various geopolitical and socio-cultural complexities. Even after five years of arriving at these conclusions and more, the state of Jammu and Kashmir still lacks a comprehensive rehabilitation plan for these children. This has further encouraged a mushroomed growth of legal and illegal institutions. Some of these institutions compromise the standard norms of functioning and yet remain the only hope for thousands rendered orphan. These institutions, therefore, are there to stay as other alternative forms of care are not available in the state. A comprehensive intervention policy is needed based on the cultural specifics of the state and incorporation of views of institutions offering aid, the state and the children. The paper introduces Small Group Residential Care Model through which it is expected that the restoration process can be made smooth and effective.

Keywords: armed conflict, children's rights, institutionalization, orphanages, rehabilitation

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Authors: Sarah Amodeo

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Drawing on the author’s research about the experiences of female immigrant students in academic Adult Education, in Montreal, Quebec, this paper deconstructs the benefits of autoethnography as a methodology for educators in Adult Education. Autoethnography is an advantageous methodology for teachers in Adult Education as it allows for deep engagement, allowing for educators to reflect on student experiences and their day-to-day realities, and in turn, allowing for professional development, improved andragogy, and changes to classroom practices. Autoethnography is a qualitative research methodology that cultivates strategies for improving adult learning. The paper begins by outlining the context that inspired autoethnography for the author’s work, highlighting the emergence of autoethnography as a method, while examining how it is evolving and drawing on foundational work that continues to inspire research. The basic autoethnographic methodologies that are explored in this paper include the use of memory work in episode formation, the use of personal photographs, and textual readings of artworks. Memory work allows for the researcher to use their professional experience and the lived/shared experiences of their students in their research, drawing on episodes from their past. Personal photographs and descriptions of artwork allow researchers to explore images of learning environments/realities in ways that compliment student experiences. Major findings of the text are examined through the analysis of categories of autoethnography. Specific categories include realism, impressionism, and conceptualism which aid in orientating the analysis and emergent themes that develop through self-study. Finally, the text presents a discussion surrounding the limitations of autoethnography, with attention to the trustworthiness and ethical issues. The paper concludes with a consideration of the implications of autoethnography for adult educators in juxtaposition with youth sector work.

Keywords: artwork, autoethnography, conceptualism, episode formation, impressionism, memory work, personal photographs, and realism, realism

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Authors: Susan Lanz, Gary T. Burke, Omid Omidvar

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The intention to transfer ownership control across family generations is acknowledged to be central to developing a theoretical understanding of how family businesses differ and are distinct as a business group. However, in practice, most business-owning families face challenges to transfer their business ownership from one family generation to the next. To date, researchers have paid little attention to how and when ownership is passed across family generations and what the dynamics of such transitions are. This is primarily due to the prevailing assumption that ownership transfer is an unimportant and legalistic issue that occurs within a wider family management succession process. Yet, the limited evidence available suggests that family ownership transfer occurs inside and outside of the management succession process and is a difficult process for business-owning families to navigate. As a result, many otherwise viable family businesses are closing, leading to unnecessary loss of jobs and knowledge. This qualitative paper examines how family members understand and navigate the ownership transfer process. This study uses an inductive qualitative research design, conducted through in-depth interviews within eight business-owning families. It draws on family development theory and shows how a wide range of family-related events and dynamics outside of family business involvement underlie and shape the ownership transfer process. The findings extend the theory on how these events trigger ownership transfer and how they shape the ownership meanings held within business-owning families. This study found that ownership transfer meanings extend beyond that of transferring the legal control and financial appropriation rights of shareholders. The study concludes there are three different stages in the process of ownership transfer -symbolic, re-balancing, and protectionist. Each stage creates distinct family social constructions of the rights of family members to hold business ownership, and each stage occurs within a specific family development phase.

Keywords: business-owning family, family development theory, ownership transfer, process

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Authors: Obadiah Nwabueze

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Bodija market is classified as Central Business District (CBD) of Ibadan North Local Government Area of Oyo State (Nigeria) because of socio economic activities, so Crime is a peculiar social issue that causes insecurity. The law enforcement agencies tasked with crime prevention and control such as the Nigerian Police have insufficient manpower, and a resultant effect is the emergence of Vigilante groups as citizen’s response to crime control and prevention (self-help). The research design adopted for this study is a case study design exploring Vigilante activities in Bodija Market. The study utilizes both quantitative and qualitative approach, sources of data includes primary and secondary sources. A sample of 127 respondents randomly picked from the 4 sections of Bodija Market through questionnaire, comprising of 50 male and 77 females which alienates issues of gender bias in addition to the 4 in-depth interview, making a total of 131 respondents. Statistical package for Social Sciences (SPSS) was used. The descriptive statistics of simple frequency, percentage, charts and graphs were computed for the analysis. Finding in the study shows that the market vigilante is able to deter and disrupt criminal activities through strategic spiritual intelligence (SSI), use of charm and juju, physical presence in strategic locations vulnerable to crime occurrence. Findings in the study also show that vigilantes collaborate with the police by assisting them in surveillance, tracking down criminals, identifying black spots, acting as informants to the police, arrest and handover criminal to police. Their challenges include poor equipment, motivation, unhealthy rivalry between the vigilante and the police. The study recommends that the government should support vigilantes with logistics and training, including patrol vehicle and radio communication. The study also recommends the integration of the informal mechanism (juju and charm) of crime detection and prevention into the formal policing strategy, an office should be created in the force commands for use of SSI.

Keywords: central business district, CBD, charm, Juju, strategic spiritual intelligence, SSI

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Authors: Oyindamola Kayode, Sarah George, Roberto Borrageiro, Mike Shirran

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A phenomenon identified by our industrial partner has experienced sag on AA3104 can body stock (CBS) transfer bar during transportation of the slab from the breakdown mill to the finishing mill. Excessive sag results in bottom scuffing of the slab onto the roller table, resulting in surface defects on the final product. It has been found that increasing the strain rate on the breakdown mill final pass results in a slab resistant to sag. The creep response for materials hot deformed at different Zener–Holloman parameter values needs to be evaluated experimentally to gain better understanding of the operating mechanism. This study investigates this identified phenomenon through laboratory simulation of the breakdown mill conditions for various strain rates by utilizing the Gleeble at UCT Centre for Materials Engineering. The experiment will determine the creep response for a range of conditions as well as quantifying the associated material microstructure (sub-grain size, grain structure etc). The experimental matrices were determined based on experimental conditions approximate to industrial hot breakdown rolling and carried out on the Gleeble 3800 at the Centre for Materials Engineering, University of Cape Town. Plane strain compression samples were used for this series of tests at an applied load that allow for better contact and exaggerated creep displacement. A tantalum barrier layer was used for increased conductivity and decreased risk of anvil welding. One set of tests with no in-situ hold time was performed, where the samples were quenched after deformation. The samples were retained for microstructure analysis of the micrographs from the light microscopy (LM), quantitative data and images from scanning electron microscopy (SEM) and energy dispersive X-ray (EDX), sub-grain size and grain structure from electron back scattered diffraction (EBSD).

Keywords: aluminium alloy, can-body stock, hot rolling, creep response, Zener-Hollomon parameter

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Authors: David Alejandro Lazo-Vasquez, Jorge Luis Balino

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In the petroleum industry, multiphase flow occurs when oil, gas, and water are transported in the same pipe through large pipeline systems. The flow can take different patterns depending on parameters like fluid velocities, pipe diameter, pipe inclination, and fluid properties. Mainly, intermittent flow is produced by the natural propagation of short and long waves, according to the Kelvin-Helmholtz Stability Theory. To model stratified flow and the onset of intermittent flow, it is crucial to have knowledge of short and long waves behavior. The two-fluid model, frequently employed for characterizing multiphase systems, becomes ill-posed for high liquid and gas velocities and large inclination angles, for short waves can develop infinite growth rates. We are interested in focusing attention on long-wave instability, which leads to the production of roll waves that may grow and result in the transition from stratified flow to intermittent flow. In this study, global and local linear stability analyses for dynamic and kinematic stability criteria predict the regions of stability of the flow for different pipe inclinations and fluid velocities in regularized and non-regularized systems, concurrently. It was possible to distinguish when: wave growth rates are absolutely bounded (stable stratified smooth flow), waves have finite growth rates (unstable stratified wavy flow), and when the equation system becomes elliptic and hyperbolization is needed. In order to bound short wave growth rates and regularize the equation system, we incorporated some lower and higher-order terms like interfacial drag and surface tension, respectively.

Keywords: linear stability analysis, multiphase flow, onset of slugging, two-fluid model regularization

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Authors: Farida Naceur

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Algerian cities experienced after the independence of the country a rapid urbanisation process fostered by population growth. In order to deal with the severe housing shortage resulted, large social public housing programs totally financed by the government were launched across the country during the eighty. Unfortunately, the standardized multistory buildings produced underwent intense deterioration and turned very quickly after their occupancy into sources of nuisance and distress. The government adopted a new housing policy in 2000, which aims to diversify housing types according to household incomes and encourage access to housing property. The model of participatory social housing emerged; it was designed for the intermediate groups, allowing them to benefit from direct financial aid and to borrow credit from banks in order to purchase their dwellings. Twenty years afterward, no assessment to date has been established to evaluate the real impact of such a strategy. The aim of this paper is to examine whether this type of housing helped to stimulate a participative dynamism among its occupants to strengthen their commitment, their involvement in the maintenance and keeping of their surroundings. For the purpose of the study, we focus our attention on various participatory social housing settlements in Batna and Biskra, two medium-sized cities in eastern Algeria. The investigation is structured in various types of analysis: a spatial analysis, observations, interviews with public authorities representatives, chief planners, and experts. In addition to this, informal interviews with occupants of various participatory social housing settlements were arranged to collect qualitative data. Occupants were asked open questions focusing on their daily life and practices in order to examine their degree of involvement in their neighbourhood’s life.

Keywords: participatory social housing, rental social housing, involvement, maintenance, social interactions, community life

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Authors: Zhenyu Zhang, Hsi-Hsien Wei

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Highway networks play a vital role in post-disaster recovery for disaster-damaged areas. Damaged bridges in such networks can disrupt the recovery activities by impeding the transportation of people, cargo, and reconstruction resources. Therefore, rapid restoration of damaged bridges is of paramount importance to long-term disaster recovery. In the post-disaster recovery phase, the key to restoration scheduling for a highway network is prioritization of bridge-repair tasks. Resilience is widely used as a measure of the ability to recover with which a network can return to its pre-disaster level of functionality. In practice, highways will be temporarily blocked during the downtime of bridge restoration, leading to the decrease of highway-network functionality. The failure to take downtime effects into account can lead to overestimation of network resilience. Additionally, post-disaster recovery of highway networks is generally divided into emergency bridge repair (EBR) in the response phase and long-term bridge repair (LBR) in the recovery phase, and both of EBR and LBR are different in terms of restoration objectives, restoration duration, budget, etc. Distinguish these two phases are important to precisely quantify highway network resilience and generate suitable restoration schedules for highway networks in the recovery phase. To address the above issues, this study proposes a novel resilience quantification method for the optimization of long-term bridge repair schedules (LBRS) taking into account the impact of EBR activities and restoration downtime on a highway network’s functionality. A time-dependent integer program with recursive functions is formulated for optimally scheduling LBR activities. Moreover, since uncertainty always exists in the LBRS problem, this paper extends the optimization model from the deterministic case to the stochastic case. A hybrid genetic algorithm that integrates a heuristic approach into a traditional genetic algorithm to accelerate the evolution process is developed. The proposed methods are tested using data from the 2008 Wenchuan earthquake, based on a regional highway network in Sichuan, China, consisting of 168 highway bridges on 36 highways connecting 25 cities/towns. The results show that, in this case, neglecting the bridge restoration downtime can lead to approximately 15% overestimation of highway network resilience. Moreover, accounting for the impact of EBR on network functionality can help to generate a more specific and reasonable LBRS. The theoretical and practical values are as follows. First, the proposed network recovery curve contributes to comprehensive quantification of highway network resilience by accounting for the impact of both restoration downtime and EBR activities on the recovery curves. Moreover, this study can improve the highway network resilience from the organizational dimension by providing bridge managers with optimal LBR strategies.

Keywords: disaster management, highway network, long-term bridge repair schedule, resilience, restoration downtime

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Authors: Bedarnia Ishak

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In the recent years, the dry reforming of methane has received considerable attention from an environmental view point because it consumes and eliminates two gases (CH4 and CO2) responsible for global warming by greenhouse effect. Many catalysts containing noble metal (Rh, Ru, Pd, Pt and Ir) or transition metal (Ni, Co and Fe) have been reported to be active in this reaction. Compared to noble metals, Ni-materials are cheap but very easily deactivated by coking. Ni-based mixed oxides structurally well-defined like perovskites and spinels are being studied because they possibly make solid solutions and allow to vary the composition and thus the performances properties. In this work, nano-sized nickel ferrite oxides are synthesized using three different methods: Co-precipitation (CP), hydrothermal (HT) and sol gel (SG) methods and characterized by XRD, Raman, XPS, BET, TPR, SEM-EDX and TEM-EDX. XRD patterns of all synthesized oxides showed the presence of NiFe2O4 spinel, confirmed by Raman spectroscopy. Hematite was present only in CP sample. Depending on the synthesis method, the surface area, particle size, as well as the surface Ni/Fe atomic ratio (XPS) and the behavior upon reduction varied. The materials were tested in methane dry reforming with CO2 at 1 atm and 650-800 °C. The catalytic activity of the spinel samples was not very high (XCH4 = 5-20 mol% and XCO2 = 25-40 mol %) when no pre-reduction step was carried out. A significant contribution of RWGS explained the low values of H2/CO ratio obtained. The reoxidation step of the catalyst carried out after reaction showed little amounts of coke deposition. The reducing pretreatment was particularly efficient in the case of SG (XCH4 = 80 mol% and XCO2 = 92 mol%, at 800 °C), with H2/CO > 1. In conclusion, the influence of preparation was strong for most samples and the catalytic behavior could be interpreted by considering the distribution of cations among octahedral (Oh) and tetrahedral (Td) sites as in (Ni2+1-xFe3+x) Td (Ni2+xFe3+2-x) OhO2-4 influenced the reducibility of materials and thus their catalytic performance.

Keywords: NiFe2O4, dry reforming of methane, spinel oxide, oxide zenc

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Authors: Bharath Anantharamaiah, Tomas Bouda, Elke Deckers, Stijn Jonckheere, Wim Desmet, Juan J. Garcia

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Automotive tyres are gaining importance recently in terms of their noise emission, not only with respect to reduction in noise, but also their perception and detection. Tyres exhibit a mechanical noise generation mechanism up to 1 kHz. However, owing to the fact that tyre is a composite of several materials, it has been difficult to model it using finite elements to predict noise at high frequencies. The currently available FE models have a reliability of about 500 Hz, the limit which, however, is not enough to perceive the roughness or sharpness of noise from tyre. These noise components are important in order to alert pedestrians on the street about passing by slow, especially electric vehicles. In order to model tyre noise behaviour up to 1 kHz, its dynamic behaviour must be accurately developed up to a 1 kHz limit using finite elements. Materials play a vital role in modelling the dynamic tyre behaviour precisely. Since tyre is a composition of several components, their precise definition in finite element simulations is necessary. However, during the tyre manufacturing process, these components are subjected to various pressures and temperatures, due to which these properties could change. Hence, material definitions are better described based on the tyre responses. In this work, the hyperelasticity of tyre component rubbers is calibrated, using the design of experiments technique from the tyre characteristic responses that are measured on a stiffness measurement machine. The viscoelasticity of rubbers are defined by the Prony series for rubbers, which are determined from the loss factor relationship between the loss and storage moduli, assuming that the rubbers are excited within the linear viscoelasticity ranges. These values of loss factor are measured and theoretically expressed as a function of rubber shore hardness or hyperelasticities. From the results of the work, there exists a good correlation between test and simulation vibrational transfer function up to 1 kHz. The model also allows flexibility, i.e., the frequency limit can also be extended, if required, by calibrating the Prony parameters of rubbers corresponding to the frequency of interest. As future work, these tyre models are used for noise generation at high frequencies and thus for tyre noise perception.

Keywords: tyre dynamics, rubber materials, prony series, hyperelasticity

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Authors: E. A. Krasikov

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As a main barrier against radioactivity outlet reactor pressure vessel (RPV) is a key component in terms of NPP safety. Therefore, present-day demands in RPV reliability enhance have to be met by all possible actions for RPV in-service embrittlement mitigation. Annealing treatment is known to be the effective measure to restore the RPV metal properties deteriorated by neutron irradiation. There are two approaches to annealing. The first one is so-called ‘dry’ high temperature (~475°C) annealing. It allows obtaining practically complete recovery, but requires the removal of the reactor core and internals. External heat source (furnace) is required to carry out RPV heat treatment. The alternative approach is to anneal RPV at a maximum coolant temperature which can be obtained using the reactor core or primary circuit pumps while operating within the RPV design limits. This low temperature «wet» annealing, although it cannot be expected to produce complete recovery, is more attractive from the practical point of view especially in cases when the removal of the internals is impossible. The first RPV «wet» annealing was done using nuclear heat (US Army SM-1A reactor). The second one was done by means of primary pumps heat (Belgian BR-3 reactor). As a rule, there is no recovery effect up to annealing and irradiation temperature difference of 70°C. It is known, however, that along with radiation embrittlement neutron irradiation may mitigate the radiation damage in metals. Therefore, we have tried to test the possibility to use the effect of radiation-induced ductilization in ‘wet’ annealing technology by means of nuclear heat utilization as heat and neutron irradiation sources at once. In support of the above-mentioned conception the 3-year duration reactor experiment on 15Cr3NiMoV type steel with preliminary irradiation at operating PWR at 270°C and following extra irradiation (87 h at 330°C) at IR-8 test reactor was fulfilled. In fact, embrittlement was partly suppressed up to value equivalent to 1,5 fold neutron fluence decrease. The degree of recovery in case of radiation enhanced annealing is equal to 27% whereas furnace annealing results in zero effect under existing conditions. Mechanism of the radiation-induced damage mitigation is proposed. It is hoped that «wet » annealing technology will help provide a better management of the RPV degradation as a factor affecting the lifetime of nuclear power plants which, together with associated management methods, will help facilitate safe and economic long-term operation of PWRs.

Keywords: controlling, embrittlement, radiation, steel, wet annealing

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