Search results for: Young Lives Study

Authors: Asma Bashir, Neha Farid, Kashif Ali, Kiran Fatima

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Background: Bacteriocins are a subclass of antimicrobial peptides that are becoming extremely important in treatments. It is possible to utilise bacteriocins in place of or in addition to traditional antibiotics. It is possible to treat a variety of infections, including Vancomycin-Resistant Staphylococcus aureus (VRSA) and Methicillin-Resistant Staphylococcus aureus (MRSA), using the targeted spectrum of activity of these microorganisms. Method: This study aimed to examine the efficiency of antibiotics and bacteriocin against VRSA and MRSA. The effects of bacteriocins, such as enterocin KAE01, enterocin KAE03, enterocin KAE05, and enterocin KAE06 isolated from Enterococcus faecium strains, alone and in combination with vancomycin and methicillin antibiotics were examined. The selection technique utilized the minimum inhibitory concentrations (MICs) against Gram-positive indicator strain ATCC 6538 Methicillin-Resistant Staphylococcus aureus (MRSA) and indicator strain KSA 02 Vancomycin-Resistant Staphylococcus aureus (VRSA). Results: We report the isolation and identification of enterocins KAE01, KAE03, KAE05, and KAE06 from food isolates of Enterococcus faecium (KAE01, KAE03, KAE05, and KAE06). After isolating the protein, it was partially purified with ammonium sulphate precipitation and purified with fast protein liquid chromatography (FPLC) procedures. Combinations of enterocin KAE01, 1 citric acid, 1 lactic acid, and microcin J25, 1 reuterin, 1 citric acid, and microcin J25, 1 reuterin, 1 lactic acid shown synergistic benefits (FIC index = 0.5) against Vancomycin-Resistant Staphylococcus aureus (VRSA). In addition, a moderately synergistic (FIC index = 0.75) interaction was seen between pediocin PA-1, 1 citric acid, 1 lactic acid, and reuterin 1 citric acid, 1 lactic acid against L. ivanovii HPB28. In the presence of acids, nisin Z exhibited a modestly synergistic effect (FIC index = 0.625-0.75); however, it exhibited additive effects (FIC index = 1) when combined with reuterin or pediocin PA-1 against L. ivanovii HPB28. The efficacy of synergistic consortiums against Gram-positive bacteria was examined. Conclusion: Combining antimicrobials with various modes of action boosted efficacy and expanded the spectrum of inhibition, particularly against multidrug-resistant pathogens, according to our research.

Keywords: Enterococcus faecium, bacteriocin, antimicrobial resistance, antagonistic activity, vancomycin-resistant Staphylococcus aureus, methicillin-resistant Staphylococcus aureus

Procedia PDF Downloads 148

Authors: Wing Mui Winnie So, Tian Luo, Zeyu Han

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To fully explore and develop the potentials of gifted students systematically and strategically by providing them with opportunities to receive education at appropriate levels, schools in Hong Kong are encouraged to adopt the "Three-Tier Implementation Model" to plan and implement the school-based gifted education, with Level Three refers to the provision of learning opportunities for the exceptionally gifted students in the form of specialist training outside the school setting by post-secondary institutions, non-government organisations, professional bodies and technology enterprises. Due to the growing concern worldwide about low interest among students in pursuing STEM (Science, Technology, Engineering, and Mathematics) careers, cultivating and boosting STEM career interest has been an emerging research focus worldwide. Although numerous studies have explored its critical contributors, little research has examined the effectiveness of comprehensive interventions such as “Studying with STEM professional”. This study aims to examine the effect on gifted students’ career interest during their participation in an off-school support programme designed and supervised by a team of STEM educators and STEM professionals from a university. Gifted students were provided opportunities and tasks to experience STEM career topics that are not included in the school syllabus, and to experience how to think and work like a STEM professional in their learning. Participants involved 40 primary school students joining the intervention programme outside the normal school setting. Research methods included adopting the STEM career interest survey and drawing tasks supplemented with writing before and after the programme, as well as interviews before the end of the programme. The semi-structured interviews focused on students’ views regarding STEM professionals; what’s it like to learn with a STEM professional; what’s it like to work and think like a STEM professional; and students’ STEM identity and career interest. The changes in gifted students’ STEM career interest and its well-recognised significant contributors, for example, STEM stereotypes, self-efficacy for STEM activities, and STEM outcome expectation, were collectively examined from the pre- and post-survey using T-test. Thematic analysis was conducted for the interview records to explore how studying with STEM professional intervention can help students understand STEM careers; build STEM identity; as well as how to think and work like a STEM professional. Results indicated a significant difference in STEM career interest before and after the intervention. The influencing mechanism was also identified from the measurement of the related contributors and the analysis of drawings and interviews. The potential of off-school support programme supervised by STEM educators and professionals to develop gifted students’ STEM career interest is argued to be further unleashed in future research and practice.

Keywords: gifted students, STEM career, STEM education, STEM professionals

Procedia PDF Downloads 74

Authors: Emmanuelle Merat, Arnaud Aubert, Sophie Cambos, Francis Vial, Patrick Beau

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Basically, consumers are sensitive to many stimuli when applying a cream: brand, packaging and indeed formulation compositions. Many studies demonstrated the influence of some stimuli such as brand, packaging, formula color and odor (e.g. in make-up applications). Those parameters influence perceived quality of the product. The objective of this work is to further investigate the relationship between nude skincare basic compositions with different textures and consumer experience. A tentative final step will be to connect the consumer feelings with key ingredients in the compositions. A new approach was developed to better understand touch-related subjective experience in consumers based on a combination of methods: sensory analysis with ten experts, preference mapping on one hundred female consumers and emotional assessments on thirty consumers (verbal and non-verbal through prosody and gesture monitoring). Finally, a methodology based on ‘sensorial trip’ (after olfactory, haptic and musical stimuli) has been experimented on the most interesting textures with 10 consumers. The results showed more or less impact depending on compositions and also on key ingredients. Three types of formulation particularly attracted the consumer: an aqueous gel, an oil-in-water emulsion, and a patented gel-in-oil formulation type. Regarding these three formulas, the preferences were both revealed through sensory and emotion tests. One was recognized as the most innovative in consumer sensory test whereas the two other formulas were discriminated in emotions evaluation. The positive emotions were highlighted especially in prosody criteria. The non-verbal analysis, which corresponds to the physical parameters of the voice, showed high pitch and amplitude values; linked to positive emotions. Verbatim, verbal content of responses (i.e., ideas, concepts, mental images), confirmed the first conclusion. On the formulas selected for their positive emotions generation, the ‘sensorial trip’ provided complementary information to characterize each emotional profile. In the second step, dedicated to better understand ingredients power, two types of ingredients demonstrated an obvious input on consumer preference: rheology modifiers and emollients. As a conclusion, nude cosmetic compositions with well-chosen textures and ingredients can positively stimulate consumer emotions contributing to capture their preference. For a complete achievement of the study, a global approach (Asia, America territories...) should be developed.

Keywords: sensory, emotion, cosmetic formulations, ingredients' influence

Procedia PDF Downloads 178

Authors: Salamah Ansari

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In absence of a comprehensive international legal regime for sovereign debt restructuring, majority of the complications arising from sovereign debt restructuring are frequently left to the uncertain market forces. The resort to market forces for sovereign debt restructuring has led to a phenomenal increase in litigations targeting assets of defaulting sovereign nations, internationally across jurisdictions with the first major wave of lawsuits against sovereigns in the 1980s with the Latin American crisis. Recent experiences substantiate that majority of obstacles faced during sovereign debt restructuring process are caused by inefficient creditor coordination and collective action problems. Collective action problems manifest as grab race, rush to exits, holdouts, the free rider problem and the rush to the courthouse. On defaulting, for a nation to successfully restructure its debt, all the creditors involved must accept some reduction in the value of their claims. As a single holdout creditor has the potential to undermine the restructuring process, hold-out creditors are snowballing with the increasing probability of earning high returns through litigations. This necessitates a mechanism to avoid holdout litigations and reinforce collective action on the part of the creditor. This can be done either through a statutory reform or through market-based contractual approach. In absence of an international sovereign bankruptcy regime, the impetus is mostly on inclusion of collective action clauses in debt contracts. The preference to contractual mechanisms vis- a vis a statutory approach can be explained with numerous reasons, but that's only part of the puzzle in trying to understand the economics of the underlying system. The contractual approach proposals advocate the inclusion of certain clauses in the debt contract for an orderly debt restructuring. These include clauses such as majority voting clauses, sharing clauses, non- acceleration clauses, initiation clauses, aggregation clauses, temporary stay on litigation clauses, priority financing clauses, and complete revelation of relevant information. However, voluntary market based contractual approach to debt workouts has its own complexities. It is a herculean task to enshrine clauses in debt contracts that are detailed enough to create an orderly debt restructuring mechanism while remaining attractive enough for creditors. Introduction of collective action clauses into debt contracts can reduce the barriers in efficient debt restructuring and also have the potential to improve the terms on which sovereigns are able to borrow. However, it should be borne in mind that such clauses are not a panacea to the huge institutional inadequacy that persists and may lead to worse restructuring outcomes.

Keywords: sovereign debt restructuring, collective action clauses, hold out creditors, litigations

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Authors: Morena Paulisic, Marli Gonan Bozac

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Business organization and management in theory are typically presented as gender- neutral. Although in practice female contribution to corporation is not questionable, gender diversity in top management of corporation is and that especially in emerging countries like Croatia. This paper brings insights into obstacles and problems which should be overcome. Furthermore, gives an introspective view on the most important promotion and motivation factors of powerful female CEOs in Croatia. The goal was to clarify perception and performance of female CEOs that contributed to their success and to determine mutual characteristics of women in corporate entrepreneurship regarding the motivation. For our study we used survey instrument that was developed for this research. The research methods used were: table research, field research, generalization method, comparative method, and statistical method (descriptive statistics and Pearson’s Chi-square test). Some result showed us that today even more women in corporations are not likely to accept more engagement at work if it harms their families (2003 – 31.9% in 2013 – 33.8%) although their main motivating factor is still interested job (2003 – 95.8%; in 2013-100%). It is also significant that 78.8 % of Croatian top managers (2013) think that women managers in Croatia are insufficiently spoken and written about, and that the reasons for this are that: (1) the society underestimates their ability (37.9%); (2) women underestimate themselves (22.4%); (3) the society still mainly focuses on male managers (20.7%) and (4) women managers avoid interviews and appearing on front pages (19%). The environment still “blocks” the natural course of advancement of women managers in organisations (entrepreneurship in general) and the main obstacle is that women must always or almost always be more capable than men in order to succeed (96.6%). Based on survey results on longitudinal research conducted in 2003 (return rate 30,8%) and 2013 (return rate 29,2%) in Croatia we expand understanding of determination indicators of corporate female entrepreneurship. Theoretically in practice gender structure at the management level (executive management, management board and supervisory board) throw years (2011- 2014) have positive score but still women remain significantly underrepresented at those positions. Findings from different sources have shown that diversity at the top of corporations’ correlates with better performance. In this paper, we have contributed to research on gender in corporate entrepreneurship by offering experiences from successful female CEOs and explanation why in social responsible society women with their characteristics can support needed changes and construct different way forward for corporations. Based on research result we can conclude that in future underrepresentation of female in corporate entrepreneurship should be overcome.

Keywords: Croatia, female entrepreneurship, glass ceiling, motivation

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Authors: G. P. Gunasinghe, Lilani Ruhunage, N. P. Ratnayake, G. V. I. Samaradivakara, H. M. R. Premasiri, A. S. Ratnayake, Nimila Dushantha, W. A. P. Weerakoon, K. B. A. Silva

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Sri Lanka is affected by different natural disasters such as tsunami, landslides, lightning, and riverine flood. Out of them, riverine floods act as a major disaster in the country. Different strategies are applied to control the impacts of flood hazards, and the expansion of river mouth is considered as one of the main activities for flood mitigation and disaster reduction. However, due to this expansion process, natural sand barriers including sand spits, barrier islands, and tidal planes are destroyed or subjected to change. This, in turn, can change the hydrodynamics and sediment dynamics of the area leading to other damages to the natural coastal features. The removal of a considerable portion of naturally formed sand barrier at Kaluganga River outlet (Calido Beach), Sri Lanka to control flooding event at Kaluthara urban area on May 2017, has become a serious issue in the area causing complete collapse of river mouth barrier spit bar system leading to rapid coastal erosion Kaluganga river outlet area and saltwater intrusion into the Kaluganga River. The present investigation is focused on assessing effects due to the removal of a considerable portion of naturally formed sand barrier at Kaluganga river mouth. For this study, the beach profiles, the bathymetric surveys, and Google Earth historical satellite images, before and after the flood event were collected and analyzed. Furthermore, a beach boundary survey was also carried out in October 2018 to support the satellite image data. The results of Google Earth satellite images and beach boundary survey data analyzed show a chronological breakdown of the sand barrier at the river outlet. The comparisons of pre and post-disaster bathymetric maps and beach profiles analysis revealed a noticeable deepening of the sea bed at the nearshore zone as well. Such deepening in the nearshore zone can cause the sea waves to break very near to the coastline. This might also lead to generate new diffraction patterns resulting in differential coastal accretion and erosion scenarios. Unless immediate mitigatory measures were not taken, the impacts may cause severe problems to the sensitive Kaluganag river mouth system.

Keywords: bathymetry, beach profiles, coastal features, river outlet, sand barrier, Sri Lanka

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Authors: Manuela Villani, Anila Xhahysa, Christopher Brooks, Marco Pagani

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The geological structure of Western Balkans is strongly affected by the collision between Adria microplate and the southwestern Euroasia margin, resulting in a considerably active seismic region. The Harmonization of Seismic Hazard Maps in the Western Balkan Countries Project (BSHAP) (2007-2011, 2012-2015) by NATO supported the preparation of new seismic hazard maps of the Western Balkan, but when inspecting the seismic hazard models produced later by these countries on a national scale, significant differences in design PGA values are observed in the border, for instance, North Albania-Montenegro, South Albania- Greece, etc. Considering the fact that the catalogues were unified and seismic sources were defined within BSHAP framework, obviously, the differences arise from the Ground Motion Prediction Equations selection, which are generally the component with highest impact on the seismic hazard assessment. At the time of the project, a modest database was present, namely 672 three-component records, whereas nowadays, this strong motion database has increased considerably up to 20,939 records with Mw ranging in the interval 3.7-7 and epicentral distance distribution from 0.47km to 490km. Statistical analysis of the strong motion database showed the lack of recordings in the moderate-to-large magnitude and short distance ranges; therefore, there is need to re-evaluate the Ground Motion Prediction Equation in light of the recently updated database and the new generations of GMMs. In some cases, it was observed that some events were more extensively documented in one database than the other, like the 1979 Montenegro earthquake, with a considerably larger number of records in the BSHAP Analogue SM database when compared to ESM23. Therefore, the strong motion flat-file provided from the Harmonization of Seismic Hazard Maps in the Western Balkan Countries Project was merged with the ESM23 database for the polygon studied in this project. After performing the preliminary residual analysis, the candidate GMPE-s were identified. This process was done using the GMPE performance metrics available within the SMT in the OpenQuake Platform. The Likelihood Model and Euclidean Distance Based Ranking (EDR) were used. Finally, for this study, a GMPE logic tree was selected and following the selection of candidate GMPEs, model weights were assigned using the average sample log-likelihood approach of Scherbaum.

Keywords: residual analysis, GMPE, western balkan, strong motion, openquake

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Authors: Danni Cheng

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Background: Preclinical and epidemiological studies have reported potential protective effects of low-density lipoprotein cholesterol (LDL-C) lowering drugs on head and neck squamous cell cancer (HNSCC) survival, but the causality was not consistent. Genetic variants associated with LDL-C lowering drug targets can predict the effects of their therapeutic inhibition on disease outcomes. Objective: We aimed to evaluate the causal association of genetically proxied cholesterol-lowering drug targets and circulating lipid traits with cancer survival in HNSCC patients stratified by human papillomavirus (HPV) status using two-sample Mendelian randomization (MR) analyses. Method: Single-nucleotide polymorphisms (SNPs) in gene region of LDL-C lowering drug targets (HMGCR, NPC1L1, CETP, PCSK9, and LDLR) associated with LDL-C levels in genome-wide association study (GWAS) from the Global Lipids Genetics Consortium (GLGC) were used to proxy LDL-C lowering drug action. SNPs proxy circulating lipids (LDL-C, HDL-C, total cholesterol, triglycerides, apoprotein A and apoprotein B) were also derived from the GLGC data. Genetic associations of these SNPs and cancer survivals were derived from 1,120 HPV-positive oropharyngeal squamous cell carcinoma (OPSCC) and 2,570 non-HPV-driven HNSCC patients in VOYAGER program. We estimated the causal associations of LDL-C lowering drugs and circulating lipids with HNSCC survival using the inverse-variance weighted method. Results: Genetically proxied HMGCR inhibition was significantly associated with worse overall survival (OS) in non-HPV-drive HNSCC patients (inverse variance-weighted hazard ratio (HR IVW), 2.64[95%CI,1.28-5.43]; P = 0.01) but better OS in HPV-positive OPSCC patients (HR IVW,0.11[95%CI,0.02-0.56]; P = 0.01). Estimates for NPC1L1 were strongly associated with worse OS in both total HNSCC (HR IVW,4.17[95%CI,1.06-16.36]; P = 0.04) and non-HPV-driven HNSCC patients (HR IVW,7.33[95%CI,1.63-32.97]; P = 0.01). A similar result was found that genetically proxied PSCK9 inhibitors were significantly associated with poor OS in non-HPV-driven HNSCC (HR IVW,1.56[95%CI,1.02 to 2.39]). Conclusion: Genetically proxied long-term HMGCR inhibition was significantly associated with decreased OS in non-HPV-driven HNSCC and increased OS in HPV-positive OPSCC. While genetically proxied NPC1L1 and PCSK9 had associations with worse OS in total and non-HPV-driven HNSCC patients. Further research is needed to understand whether these drugs have consistent associations with head and neck tumor outcomes.

Keywords: Mendelian randomization analysis, head and neck cancer, cancer survival, cholesterol, statin

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Authors: Kunihisa Kakumoto

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“Purpose”: Global environmental issues are now being raised in a global dimension. By predicting sprawl phenomena beyond the limits of nature with algorithms, we can expect to protect our social life within the limits of nature. It turns out that the sustainable state of the planet now consists in maintaining a balance between the capabilities of nature and the possibilities of our social life. The amount of water on earth is finite. Sustainability is therefore highly dependent on water capacity. A certain amount of water is stored in the forest by planting and green space, and the amount of water can be considered in relation to the green space. CO2 is also absorbed by green plants. "Possible measurements and methods": The concept of the solar community has been introduced in technical papers on the occasion of many international conferences. The solar community concept is based on data collected from one solar model house. This algorithmic study simulates the amount of water stored by lush green vegetation. In addition, we calculated and compared the amount of CO2 emissions from the Taiyo Community and the amount of CO2 reduction from greening. Based on the trial calculation results of these solar communities, we are simulating the sustainable state of the earth as an algorithm trial calculation result. We believe that we should also consider the composition of this solar community group using digital technology as control technology. "Conclusion": We consider the solar community as a prototype for finding sustainable conditions for the planet. The role of water is very important as the supply capacity of water is limited. However, the circulation of social life is not constructed according to the mechanism of nature. This simulation trial calculation is explained using the total water supply volume as an example. According to this process, algorithmic calculations consider the total capacity of the water supply and the population and habitable numbers of the area. Green vegetated land is very important to keep enough water. Green vegetation is also very important to maintain CO2 balance. A simulation trial calculation is possible from the relationship between the CO2 emissions of the solar community and the amount of CO2 reduction due to greening. In order to find this total balance and sustainable conditions, the algorithmic simulation calculation takes into account lush vegetation and total water supply. Research to find sustainable conditions is done by simulating an algorithmic model of the solar community as a prototype. In this one prototype example, it's balanced. The activities of our social life must take place within the permissive limits of natural mechanisms. Of course, we aim for a more ideal balance by utilizing auxiliary digital control technology such as AI.

Keywords: solar community, sustainability, prototype, algorithmic simulation

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Authors: Christopher R. Triggle, Hong Ding, Khaled Machaca, Gnanapragasam Arunachalam

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The antidiabetic drug, metformin, has been in clinical use for over 50 years and remains the first choice drug for the treatment of type two diabetes. In addition to its effectiveness as an oral anti-hyperglycaemic drug metformin also possesses vasculoprotective effects that are assumed to be secondary to its ability to reduce insulin resistance and control glycated hemoglobin levels; however, recent data from our laboratory indicate that metformin also has direct vasoprotective effects that are mediated, at least in part, via the anti-ageing gene, SIRT1. Diabetes is a major risk factor for the development of cardiovascular disease (CVD) and it is also well established that tobacco use further enhances the risk of CVD; however, it is not known whether treatment with metformin can offset the negative effects of diabetes and tobacco use on cardiac function. The current study was therefore designed to investigate 1: the effects of hyperglycaemia (HG) either alone or in the presence of elevated fatty acids (palmitate) and nicotine on the protein expression levels of the deacetylase sirtuin 1 (the protein product of SIRT1), anti-apoptotic Bcl-2, pro-apoptotic BIM and the pro-apoptotic, tumour suppressor protein, acetylated p53 in cardiomyocytes. 2: the ability of metformin to prevent the detrimental effects of HG, palmitate and nicotine on cardiomyocyte survival. Cell culture protocols were designed using a rat cardiomyocyte cell line, H9c2, either under normal glycaemic (NG) conditions of 5.5mM glucose, or hyperglycaemic conditions (HG) of 25mM glucose with, or without, added palmitate (250μM) or nicotine (1.0mM) for 24h. Immuno-blotting was used to detect the expression of sirtuin 1, Bcl-2, BIM, acetylated (Ac)-p53, p53 with β-actin used as the reference protein. Exposure to HG, palmitate, or nicotine alone significantly reduced expression of sirtuin1, Bcl-2 and raised the expression levels of acetylated p53 and BIM; however, the combination of HG, palmitate and nicotine had a synergistic effect to significantly suppress the expression levels of sirtuin 1 and Bcl-2, but further enhanced the expression of Ac-p53, and BIM. The inclusion of 1000μM, but not 50μM, metformin in the H9c2 cell culture protocol prevented the effects of HG, palmitate and nicotine on the pro-apoptotic pathways. Collectively these data indicate that metformin, in addition to its anti-hyperglycaemic and vasculoprotective properties, also has direct cardioprotective actions that offset the negative effects of hyerglycaemia, elevated free fatty acids and nicotine on cardiac cell survival. These data are of particular significance for the treatment of patients with diabetes who are also smokers as the inclusion of metformin in their therapeutic treatment plan should help reduce cardiac-related morbidity and mortality.

Keywords: apoptosis, cardiac muscle, diabetes, metformin, nicotine

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Authors: Zhijie Li, Wenhui Peng, Zelong Yuan, Jianchun Wang

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Turbulence is a complex phenomenon that plays a crucial role in various fields, such as engineering, atmospheric science, and fluid dynamics. Predicting and understanding its behavior over long time scales have been challenging tasks. Traditional methods, such as large-eddy simulation (LES), have provided valuable insights but are computationally expensive. In the past few years, machine learning methods have experienced rapid development, leading to significant improvements in computational speed. However, ensuring stable and accurate long-term predictions remains a challenging task for these methods. In this study, we introduce the implicit U-net enhanced Fourier neural operator (IU-FNO) as a solution for stable and efficient long-term predictions of the nonlinear dynamics in three-dimensional (3D) turbulence. The IU-FNO model combines implicit re-current Fourier layers to deepen the network and incorporates the U-Net architecture to accurately capture small-scale flow structures. We evaluate the performance of the IU-FNO model through extensive large-eddy simulations of three types of 3D turbulence: forced homogeneous isotropic turbulence (HIT), temporally evolving turbulent mixing layer, and decaying homogeneous isotropic turbulence. The results demonstrate that the IU-FNO model outperforms other FNO-based models, including vanilla FNO, implicit FNO (IFNO), and U-net enhanced FNO (U-FNO), as well as the dynamic Smagorinsky model (DSM), in predicting various turbulence statistics. Specifically, the IU-FNO model exhibits improved accuracy in predicting the velocity spectrum, probability density functions (PDFs) of vorticity and velocity increments, and instantaneous spatial structures of the flow field. Furthermore, the IU-FNO model addresses the stability issues encountered in long-term predictions, which were limitations of previous FNO models. In addition to its superior performance, the IU-FNO model offers faster computational speed compared to traditional large-eddy simulations using the DSM model. It also demonstrates generalization capabilities to higher Taylor-Reynolds numbers and unseen flow regimes, such as decaying turbulence. Overall, the IU-FNO model presents a promising approach for long-term dynamics prediction in 3D turbulence, providing improved accuracy, stability, and computational efficiency compared to existing methods.

Keywords: data-driven, Fourier neural operator, large eddy simulation, fluid dynamics

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Authors: Guoyu Wang, Meilian Zhang, Chunhui LI, Bing Ren

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In recent decades, a variety of floating structures have played a crucial role in ocean and marine engineering, such as ships, offshore platforms, floating breakwaters, fish farms, floating airports, etc. It is common for floating structures to suffer from loadings under waves, and the responses of the structures mounted in marine environments have a significant relation to the wave impacts. The interaction between surface waves and floating structures is one of the important issues in ship or marine structure design to increase performance and efficiency. With the progress of computational fluid dynamics, a number of numerical models based on the NS equations in the time domain have been developed to explore the above problem, such as the finite difference method or the finite volume method. Those traditional numerical simulation techniques for moving bodies are grid-based, which may encounter some difficulties when treating a large free surface deformation and a moving boundary. In these models, the moving structures in a Lagrangian formulation need to be appropriately described in grids, and the special treatment of the moving boundary is inevitable. Nevertheless, in the mesh-based models, the movement of the grid near the structure or the communication between the moving Lagrangian structure and Eulerian meshes will increase the algorithm complexity. Fortunately, these challenges can be avoided by the meshless particle methods. In the present study, a moving particle semi-implicit model is explored for the numerical simulation of fluid–structure interaction with surface flows, especially for coupling of fluid and moving rigid body. The equivalent momentum transfer method is proposed and derived for the coupling of fluid and rigid moving body. The structure is discretized into a group of solid particles, which are assumed as fluid particles involved in solving the NS equation altogether with the surrounding fluid particles. The momentum conservation is ensured by the transfer from those fluid particles to the corresponding solid particles. Then, the position of the solid particles is updated to keep the initial shape of the structure. Using the proposed method, the motions of a free-floating body in regular waves are numerically studied. The wave surface evaluation and the dynamic response of the floating body are presented. There is good agreement when the numerical results, such as the sway, heave, and roll of the floating body, are compared with the experimental and other numerical data. It is demonstrated that the presented MPS model is effective for the numerical simulation of fluid-structure interaction.

Keywords: floating body, fluid structure interaction, MPS, particle method, waves

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Authors: Saeed Bagherifam, Trevor Brown, Chris Fellows, Ravi Naidu

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Over the last century, rapid urbanization, industrial emissions, and mining activities have resulted in widespread contamination of the environment by heavy metal(loid)s. Arsenic (As) is a toxic metalloid belonging to group 15 of the periodic table, which occurs naturally at low concentrations in soils and the earth’s crust, although concentrations can be significantly elevated in natural systems as a result of dispersion from anthropogenic sources, e.g., mining activities. Bioavailability is the fraction of a contaminant in soils that is available for uptake by plants, food chains, and humans and therefore presents the greatest risk to terrestrial ecosystems. Numerous attempts have been made to establish in situ and ex-situ technologies of remedial action for remediation of arsenic-contaminated soils. In situ stabilization techniques are based on deactivation or chemical immobilization of metalloid(s) in soil by means of soil amendments, which consequently reduce the bioavailability (for biota) and bioaccessibility (for humans) of metalloids due to the formation of low-solubility products or precipitates. This study investigated the effectiveness of two different types of synthetic manganese and iron oxides (birnessite and goethite) for stabilization of As in a soil spiked with 1000 mg kg⁻¹ of As and treated with 10% dosages of soil amendments. Birnessite was made using HCl and KMnO₄, and goethite was synthesized by the dropwise addition of KOH into Fe(NO₃) solution. The resulting contaminated soils were subjected to a series of chemical extraction studies including sequential extraction (BCR method), single-step extraction with distilled (DI) water, 2M HNO₃ and simplified bioaccessibility extraction tests (SBET) for estimation of bioaccessible fractions of As in two different soil fractions ( < 250 µm and < 2 mm). Concentrations of As in samples were measured using inductively coupled plasma mass spectrometry (ICP-MS). The results showed that soil with birnessite reduced bioaccessibility of As by up to 92% in both soil fractions. Furthermore, the results of single-step extractions revealed that the application of both birnessite and Goethite reduced DI water and HNO₃ extractable amounts of arsenic by 75, 75, 91, and 57%, respectively. Moreover, the results of the sequential extraction studies showed that both birnessite and goethite dramatically reduced the exchangeable fraction of As in soils. However, the amounts of recalcitrant fractions were higher in birnessite, and Goethite amended soils. The results revealed that the application of both birnessite and goethite significantly reduced bioavailability and the exchangeable fraction of As in contaminated soils, and therefore birnessite and Goethite amendments might be considered as promising adsorbents for stabilization and remediation of As contaminated soils.

Keywords: arsenic, bioavailability, in situ stabilisation, metalloid(s) contaminated soils

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Authors: Foong Kiew Ooi, Aidi Naim Mohamad Samsani, Chee Keong Chen, Mohamed Saat Ismail

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Introduction: Prolonged exercise in a hot and humid environment can result in glycogen depletion and associated with loss of body fluid. Carbohydrate contained in sports beverages is beneficial for improving sports performance and preventing dehydration. Carbohydrate contained in honey is believed can be served as an alternative form of carbohydrate for enhancing sports performance. Objective: To investigate the effectiveness of honey drink compared to sports drink as a recovery aid for running performance and physiological parameters in the heat. Method: Ten male recreational athletes (age: 22.2 ± 2.0 years, VO2max: 51.5 ± 3.7 ml.kg-1.min-1) participated in this randomized cross-over study. On each trial, participants were required to run for 1 hour in the glycogen depletion phase (Run-1), followed by a rehydration phase for 2 hours and subsequently a 20 minutes time trial performance (Run-2). During Run-1, subjects were required to run on the treadmill in the heat (31°C) with 70% relative humidity at 70 % of their VO2max. During rehydration phase, participants drank either honey drink or sports drink, or plain water with amount equivalent to 150% of body weight loss in dispersed interval (60 %, 50 % and 40 %) at 0 min, 30 min and 60 min respectively. Subsequently, time trial was performed by the participants in 20 minutes and the longest distance covered was recorded. Physiological parameters were analysed using two-way ANOVA with repeated measure and time trial performance was analysed using one-way ANOVA. Results: Result showed that Acacia honey elicited a better time trial performance with significantly longer distance compared to water trial (P<0.05). However, there was no significant difference between Acacia honey and sport drink trials (P > 0.05). Acacia honey and sports drink trials elicited 249 m (8.24 %) and 211 m (6.79 %) longer in distance compared to the water trial respectively. For physiological parameters, plasma glucose, plasma insulin and plasma free fatty acids in Acacia honey and sports drink trials were significantly higher compared to the water trial respectively during rehydration phase and time trial running performance phase. There were no significant differences in body weight changes, oxygen uptake, hematocrit, plasma volume changes and plasma cortisol in all the trials. Conclusion: Acacia honey elicited greatest beneficial effects on sports performance among the drinks, thus it has potential to be used for rehydration in athletes who train and compete in hot environment.

Keywords: honey drink, rehydration, sports performance, plasma glucose, plasma insulin, plasma cortisol

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Authors: Margareta Simina Stanc, Aurel Mototolea, Tiberiu Potarniche

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The city of Constanta (former Köstence) is located in the Dobrogea region, on the west shore of the Black Sea. Between 1420-1878, Dobrogea was a possession of the Ottoman Empire. Archaeological researches starting with the second half of the 20th century revealed various traces of the Ottoman period in this region. Between 2016-2018, preventive archaeological research conducted in the perimeter of the old Ottoman city of Köstence led to the discovery of structures of habitation as well as of numerous artifacts of the Ottoman period (pottery, coins, buckles, etc.). This study uses the analysis of these new discoveries to complete the picture of daily life in the Ottoman period. In 2017, in the peninsular area of Constanta, preventive archaeological research began at a point in the former Ottoman area. In the range between the current ironing level and the -1.5m depth, the Ottoman period materials appeared constantly. It is worth noting the structure of a large building that has been repaired at least once but could not be fully investigated. In parallel to this wall, there was arranged a transversally arranged brick-lined drainage channel. The drainage channel is poured into a tank (hazna), filled with various vintage materials, but mainly gilded ceramics and iron objects. This type of hazna is commonly found in Constanta for the pre-modern and modern period due to the lack of a sewage system in the peninsular area. A similar structure, probably fountain, was discovered in 2016 in another part of the old city. An interesting piece is that of a cup (probably) Persians and a bowl belonging to Kütahya style, both of the 17th century, proof of commercial routes passing through Constanta during that period and indirectly confirming the documentary testimonies of the time. Also, can be mentioned the discovery, in the year 2016, on the occasion of underwater research carried out by specialists of the department of the Constanta Museum, at a depth of 15 meters, a Turkish oil lamp (17th - the beginning of the 18th century), among other objects of a sunken ship. The archaeological pieces, in a fragmentary or integral state, found in research campaigns 2016-2018, are undergoing processing or restoration, leaving out all the available information, and establishing exact analogies. These discoveries bring new data to the knowledge of daily life during the Ottoman administration in the former Köstence, a locality on the periphery of the Islamic world.

Keywords: habitation, material culture, Ottoman administration, Ottoman archaeology, periphery

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Authors: Zhihui Liu, Dongmei Hao, Qian Qiu, Yang An, Lin Yang, Song Zhang, Yimin Yang, Xuwen Li, Dingchang Zheng

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Premature birth, defined as birth before 37 completed weeks of gestation is a leading cause of neonatal morbidity and mortality and has long-term adverse consequences for health. It has recently been reported that the worldwide preterm birth rate is around 10%. The existing measurement techniques for diagnosing preterm delivery include tocodynamometer, ultrasound and fetal fibronectin. However, they are subjective, or suffer from high measurement variability and inaccurate diagnosis and prediction of preterm labor. Electrohysterography (EHG) method based on recording of uterine electrical activity by electrodes attached to maternal abdomen, is a promising method to assess uterine activity and diagnose preterm labor. The purpose of this study is to analyze the difference of EHG signal features between term labor and preterm labor. Free access database was used with 300 signals acquired in two groups of pregnant women who delivered at term (262 cases) and preterm (38 cases). Among them, EHG signals from 38 term labor and 38 preterm labor were preprocessed with band-pass Butterworth filters of 0.08–4Hz. Then, EHG signal features were extracted, which comprised classical time domain description including root mean square and zero-crossing number, spectral parameters including peak frequency, mean frequency and median frequency, wavelet packet coefficients, autoregression (AR) model coefficients, and nonlinear measures including maximal Lyapunov exponent, sample entropy and correlation dimension. Their statistical significance for recognition of two groups of recordings was provided. The results showed that mean frequency of preterm labor was significantly smaller than term labor (p < 0.05). 5 coefficients of AR model showed significant difference between term labor and preterm labor. The maximal Lyapunov exponent of early preterm (time of recording < the 26th week of gestation) was significantly smaller than early term. The sample entropy of late preterm (time of recording > the 26th week of gestation) was significantly smaller than late term. There was no significant difference for other features between the term labor and preterm labor groups. Any future work regarding classification should therefore focus on using multiple techniques, with the mean frequency, AR coefficients, maximal Lyapunov exponent and the sample entropy being among the prime candidates. Even if these methods are not yet useful for clinical practice, they do bring the most promising indicators for the preterm labor.

Keywords: electrohysterogram, feature, preterm labor, term labor

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Authors: S. Dodd

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This presentation examines the gender gap in leadership positions at colleges and universities within the United States. Despite the fact that women now outnumber men in earning doctorate degrees, women continue to hold far fewer positions of educational leadership, and still, earn less money than men do at every level. Considering the lack of female representation in positions of leadership, there are clearly outside variables preventing women from attaining these positions, despite their educational attainment. Following this study, the American Council on Education (ACE) set a goal to achieve an equal percentage of females holding college presidency positions by the year 2030. This goal is particularly ambitious, especially when considering the gender disparity at all ranks in higher education. Men still hold nearly 70% of all full professorships at degree-granting institutions. Even when women are equally represented in numbers, men typically hold a higher rank and are more likely to be tenured. Across all four-year colleges and universities in the United States, men earn more money than women at every rank and in every discipline. There are over twice as many men than women represented on governing boards, who help formed and uphold campus policies. The fact that the low percentage of female presidents has remained static for many years deepens the challenge for the ACE. Although emphasizing the need to create greater opportunities for women in educational administration is admirable, it is difficult to simplify the social forces that create and uphold the status quo of male leadership. When aiming to ensure 'women' hold 50% of all college presidency positions, it is important to consider how the intersections of race, social class, and other factors also correlate with lower job status. This presentation explores how gendered notions of leadership begin in a child’s early years and are carried into future careers, and how these conceptualizations impact the creation and upholding of educational policies at every academic level. Current research that emphasizes the importance establishing a bottom-up approach to a gender equity infrastructure for children early in their educational careers will be discussed. A top-down approach starting with female college presidents is incomplete and insufficient if the mindsets of the youth who will one day be entering those institutions of higher education are not also taken into consideration. Although ACE has established this lofty goal for female college presidencies by the year 2030, a road map for this will ensue, has not yet been provided. The talent pool of women who are educated and experienced for such positions is vast, but acknowledging the social barriers existing for women in these positions will be crucial to making the changes necessary for these leadership opportunities to be long lasting and successful.

Keywords: equity, higher education, leadership, women

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Authors: Evangelos G. Ilias, Panagiotis G. Ilias, Vasileios T. Popotas

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The United Kingdom has one of the oldest railway networks in the world dating back to 1825 when the world’s first passenger railway was opened. The network has some 40,000 bridges of various construction types using a wide range of materials including masonry, steel, cast iron, wrought iron, concrete and timber. It is commonly accepted that the successful operation of the network is vital for the economy of the United Kingdom, consequently the cost effective maintenance of the existing infrastructure is a high priority to maintain the operability of the network, prevent deterioration and to extend the life of the assets. Every bridge on the railway network is required to be assessed every eighteen years and a structured approach to assessments is adopted with three main types of progressively more detailed assessments used. These assessment types include Level 0 (standardized spreadsheet assessment tools), Level 1 (analytical hand calculations) and Level 2 (generally finite element analyses). There is a degree of conservatism in the first two types of assessment dictated to some extent by the relevant standards which can lead to some structures not achieving the required load rating. In these situations, a Level 2 Assessment is often carried out using finite element analysis to uncover ‘latent strength’ and improve the load rating. If successful, the more sophisticated analysis can save on costly strengthening or replacement works and avoid disruption to the operational railway. This paper presents the ‘strengthening by assessment’ achieved by Level 2 analyses. The use of more accurate analysis assumptions and the implementation of non-linear modelling and functions (material, geometric and support) to better understand buckling modes and the structural behaviour of historic construction details that are not specifically covered by assessment codes are outlined. Metallic bridges which are susceptible to loss of section size through corrosion have largest scope for improvement by the Level 2 Assessment methodology. Three case studies are presented, demonstrating the effectiveness of the sophisticated Level 2 Assessment methodology using finite element analysis against the conservative approaches employed for Level 0 and Level 1 Assessments. One rail overbridge and two rail underbridges that did not achieve the required load rating by means of a Level 1 Assessment due to the inadequate restraint provided by U-Frame action are examined and the increase in assessed capacity given by the Level 2 Assessment is outlined.

Keywords: assessment, bridges, buckling, finite element analysis, non-linear modelling, strengthening

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Authors: Priyal Sepaha

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A refugee crisis is manifested by challenges, both for the refugees and the asylum giving state. The situation turns into a mega-crisis when the situation is prejudicially handled by the home state, inappropriate refugee laws, exploding refugee population, and above all, no hope of any foreseeable solution or remedy. This paper studies the impact on the capability of stateless Rohingyas to migrate and seek refuge due to the enforcement of rigid criteria of movement imposed both by Myanmar as well as the adjoining countries in the name of national security. This theoretical study identifies the issues and the key factors and players which have precipitated the crisis. It further discusses the possible ramifications in the home, asylum giving, and the adjoining countries for not discharging their roles aptly. Additionally, an attempt has been made to understand the scarce response given to the impending crisis by the regional organizations like SAARC, ASEAN and CHOGAM as well as international organizations like United Nations Human Rights Council, Security Council, Office of High Commissioner for Refugees and so on, in the name of inadequacy of monetary funds and physical resources. Based on the refugee laws and practices pertaining to the case of Rohingyas, this paper analyses that the Rohingya Crisis is in dire need of an effective action plan to curb and resolve the biggest humanitarian crisis situation of the century. This mounting human tragedy can be mitigated permanently, by strengthening existing and creating new interdependencies among all stakeholders, as further ignorance can drive the countries of the Indian Sub-continent, in particular, and South East Asia, by and large into a violent civil war for seizing long-awaited civil rights by the marginalized Rohingyas. To curb this mass crisis, it will require the application of coercive pressure and diplomatic pursuance on the home country to acknowledge the rights of its fleeing citizens. This further necessitates mustering adequate monetary funds and physical resources for the asylum providing state. Additional challenges such as devising mechanisms for the refugee’s safe return, comprehensive planning for their holistic economic development and rehabilitation plan are needed. These, however, can only come into effect with a conscious strive by the regional and international community to fulfil their assigned role.

Keywords: asylum, citizenship, crisis, humanitarian, human rights, refugee, rohingya

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Authors: Jay Raval

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Sports and physical fitness have been a vital component of our civilization. It is such a power which, motivates and inspires every individual, communities and even countries to be aware of the physical and mental health. All though, sports play vital role in the overall development of the nation, but in the developing countries such as India, this culture of sports is yet to be motivated. However, in India lack of sporting culture has held back the growth of a similar industry in the past, despite the growing awareness and interest in various different sports besides cricket. Hence, due to a lack of sporting culture, corporate investments in India’s sports have traditionally been limited to only non-profit corporate social responsibility activities and initiatives. From past couple of years, India has come up with new initiatives such as Indian Premier League (Cricket), Hockey India League, Indian Badminton League, Pro Kabaddi League, and Indian Super League (Football) which help to boost Indian sports culture and thereby increase economy of the country. Out of 29 states of India, among all of those competitive states, Gujarat is showing very rapid increase in sports participation. Khel Mahakumbh, the competition conducted for the last six years has been a giant step in this direction and covers rural and urban areas of Gujarat. The objective of the research is to address the overall development of the sports system. Sports system includes infrastructure, coaches, resources, and participants. The current existing system is not disabled friendly. This research paper highlights adequate steps in order to improve and sort out pressing issues in the sports system. Education system is highly academic-centric with a definite trend towards reducing school sports and extra-curricular sports in the Gujarat state. Constituents of this research work make an attempt to evaluate the framework of the Olympic Charter, the Sports Authority of India, the Indian Olympics Association and the National Sports Federations. It explores the areas that need to be revamped, rejuvenated and reoriented to function in an open, democratic, equitable, transparent and accountable manner. Research is based on mixed method approach. It is used for the data collection which includes the personal interviews, document analysis and the use of news article. Quality assurance is also tested by conducting the trustworthiness of the paper. Mixed method helps to strengthen the analysis part and give strong base for the discussion during the analysis.

Keywords: physical development, sports authority of India, sports policy, women empowerment

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Authors: Meera Tandan, Mohan Timilsina, Martin Cormican, Akke Vellinga

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Background: In general practice, many infections are treated empirically without microbiological confirmation. Understanding susceptibility of antimicrobials during empirical prescribing can be helpful to reduce inappropriate prescribing. This study aims to apply a prediction model using a decision tree approach to predict the antimicrobial resistance (AMR) of urinary tract infections (UTI) based on non-clinical features of patients over 65 years. Decision tree models are a novel idea to predict the outcome of AMR at an initial stage. Method: Data was extracted from the database of the microbiological laboratory of the University Hospitals Galway on all antimicrobial susceptibility testing (AST) of urine specimens from patients over the age of 65 from January 2011 to December 2014. The primary endpoint was resistance to common antimicrobials (Nitrofurantoin, trimethoprim, ciprofloxacin, co-amoxiclav and amoxicillin) used to treat UTI. A classification and regression tree (CART) model was generated with the outcome ‘resistant infection’. The importance of each predictor (the number of previous samples, age, gender, location (nursing home, hospital, community) and causative agent) on antimicrobial resistance was estimated. Sensitivity, specificity, negative predictive (NPV) and positive predictive (PPV) values were used to evaluate the performance of the model. Seventy-five percent (75%) of the data were used as a training set and validation of the model was performed with the remaining 25% of the dataset. Results: A total of 9805 UTI patients over 65 years had their urine sample submitted for AST at least once over the four years. E.coli, Klebsiella, Proteus species were the most commonly identified pathogens among the UTI patients without catheter whereas Sertia, Staphylococcus aureus; Enterobacter was common with the catheter. The validated CART model shows slight differences in the sensitivity, specificity, PPV and NPV in between the models with and without the causative organisms. The sensitivity, specificity, PPV and NPV for the model with non-clinical predictors was between 74% and 88% depending on the antimicrobial. Conclusion: The CART models developed using non-clinical predictors have good performance when predicting antimicrobial resistance. These models predict which antimicrobial may be the most appropriate based on non-clinical factors. Other CART models, prospective data collection and validation and an increasing number of non-clinical factors will improve model performance. The presented model provides an alternative approach to decision making on antimicrobial prescribing for UTIs in older patients.

Keywords: antimicrobial resistance, urinary tract infection, prediction, decision tree

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Authors: Feng-Sheng Wang, Chao-Ting Cheng

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Developing a drug from conception to launch is costly and time-consuming. Computer-aided methods can reduce research costs and accelerate the development process during the early drug discovery and development stages. This study developed a fuzzy multi-objective hierarchical optimization framework for identifying potential anticancer targets in a metabolic model. First, RNA-seq expression data of colorectal cancer samples and their healthy counterparts were used to reconstruct tissue-specific genome-scale metabolic models. The aim of the optimization framework was to identify anticancer targets that lead to cancer cell death and evaluate metabolic flux perturbations in normal cells that have been caused by cancer treatment. Four objectives were established in the optimization framework to evaluate the mortality of cancer cells for treatment and to minimize side effects causing toxicity-induced tumorigenesis on normal cells and smaller metabolic perturbations. Through fuzzy set theory, a multiobjective optimization problem was converted into a trilevel maximizing decision-making (MDM) problem. The applied nested hybrid differential evolution was applied to solve the trilevel MDM problem using two nutrient media to identify anticancer targets in the genome-scale metabolic model of colorectal cancer, respectively. Using Dulbecco’s Modified Eagle Medium (DMEM), the computational results reveal that the identified anticancer targets were mostly involved in cholesterol biosynthesis, pyrimidine and purine metabolisms, glycerophospholipid biosynthetic pathway and sphingolipid pathway. However, using Ham’s medium, the genes involved in cholesterol biosynthesis were unidentifiable. A comparison of the uptake reactions for the DMEM and Ham’s medium revealed that no cholesterol uptake reaction was included in DMEM. Two additional media, i.e., a cholesterol uptake reaction was included in DMEM and excluded in HAM, were respectively used to investigate the relationship of tumor cell growth with nutrient components and anticancer target genes. The genes involved in the cholesterol biosynthesis were also revealed to be determinable if a cholesterol uptake reaction was not induced when the cells were in the culture medium. However, the genes involved in cholesterol biosynthesis became unidentifiable if such a reaction was induced.

Keywords: Cancer metabolism, genome-scale metabolic model, constraint-based model, multilevel optimization, fuzzy optimization, hybrid differential evolution

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Authors: Hing Hao Chan, Thomas Richard, Masood Mostofi

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The mining industry relies on an estimate of rock strength at several stages of a mine life cycle: mining (excavating, blasting, tunnelling) and processing (crushing and grinding), both very energy-intensive activities. An effective comminution design that can yield significant dividends often requires a reliable estimate of the material rock strength. Common laboratory tests such as rod, ball mill, and uniaxial compressive strength share common shortcomings such as time, sample preparation, bias in plug selection cost, repeatability, and sample amount to ensure reliable estimates. In this paper, the authors present a methodology to derive an estimate of the rock strength from drilling data recorded while coring with a diamond core head. The work presented in this paper builds on a phenomenological model of the bit-rock interface proposed by Franca et al. (2015) and is inspired by the now well-established use of the scratch test with PDC (Polycrystalline Diamond Compact) cutter to derive the rock uniaxial compressive strength. The first part of the paper introduces the phenomenological model of the bit-rock interface for a diamond core head that relates the forces acting on the drill bit (torque, axial thrust) to the bit kinematic variables (rate of penetration and angular velocity) and introduces the intrinsic specific energy or the energy required to drill a unit volume of rock for an ideally sharp drilling tool (meaning ideally sharp diamonds and no contact between the bit matrix and rock debris) that is found well correlated to the rock uniaxial compressive strength for PDC and roller cone bits. The second part describes the laboratory drill rig, the experimental procedure that is tailored to minimize the effect of diamond polishing over the duration of the experiments, and the step-by-step methodology to derive the intrinsic specific energy from the recorded data. The third section presents the results and shows that the intrinsic specific energy correlates well to the uniaxial compressive strength for the 11 tested rock materials (7 sedimentary and 4 igneous rocks). The last section discusses best drilling practices and a method to estimate the rock strength from field drilling data considering the compliance of the drill string and frictional losses along the borehole. The approach is illustrated with a case study from drilling data recorded while drilling an exploration well in Australia.

Keywords: bit-rock interaction, drilling experiment, impregnated diamond drilling, uniaxial compressive strength

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Authors: Xiang Zheng, Zhaoping Zhong

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In this study, Aspen Plus was used to simulate the whole process of biomass conversion to liquid fuel in different ways, and the main results of material and energy flow were obtained. The process optimization and evaluation were carried out on the four routes of cellulosic biomass pyrolysis gasification low-carbon olefin synthesis olefin oligomerization, biomass water pyrolysis and polymerization to jet fuel, biomass fermentation to ethanol, and biomass pyrolysis to liquid fuel. The environmental impacts of three biomass species (poplar wood, corn stover, and rice husk) were compared by the gasification synthesis pathway. The global warming potential, acidification potential, and eutrophication potential of the three biomasses were the same as those of rice husk > poplar wood > corn stover. In terms of human health hazard potential and solid waste potential, the results were poplar > rice husk > corn stover. In the popular pathway, 100 kg of poplar biomass was input to obtain 11.9 kg of aviation coal fraction and 6.3 kg of gasoline fraction. The energy conversion rate of the system was 31.6% when the output product energy included only the aviation coal product. In the basic process of hydrothermal depolymerization process, 14.41 kg aviation kerosene was produced per 100 kg biomass. The energy conversion rate of the basic process was 33.09%, which can be increased to 38.47% after the optimal utilization of lignin gasification and steam reforming for hydrogen production. The total exergy efficiency of the system increased from 30.48% to 34.43% after optimization, and the exergy loss mainly came from the concentration of precursor dilute solution. Global warming potential in environmental impact is mostly affected by the production process. Poplar wood was used as raw material in the process of ethanol production from cellulosic biomass. The simulation results showed that 827.4 kg of pretreatment mixture, 450.6 kg of fermentation broth, and 24.8 kg of ethanol were produced per 100 kg of biomass. The power output of boiler combustion reached 94.1 MJ, the unit power consumption in the process was 174.9 MJ, and the energy conversion rate was 33.5%. The environmental impact was mainly concentrated in the production process and agricultural processes. On the basis of the original biomass pyrolysis to liquid fuel, the enzymatic hydrolysis lignin residue produced by cellulose fermentation to produce ethanol was used as the pyrolysis raw material, and the fermentation and pyrolysis processes were coupled. In the coupled process, 24.8 kg ethanol and 4.78 kg upgraded liquid fuel were produced per 100 kg biomass with an energy conversion rate of 35.13%.

Keywords: biomass conversion, biofuel, process optimization, life cycle assessment

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Authors: Christian Doppler, Gernot Hirschl, Gerhard Zsiga

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Starting from 2020, an EU-wide CO2-limitation of 95g/km is scheduled for the average of an OEMs passenger car fleet. Considering that, further measures of optimization on the diesel cycle will be necessary in order to reduce fuel consumption and emissions while keeping performance values adequate at the least. The present article deals with charge air cooling (CAC) on the basis of a diesel passenger car model in a 0D/1D-working process calculation environment. The considered engine is a 2.4 litre EURO VI diesel engine with variable geometry turbocharger (VGT) and low-pressure exhaust gas recirculation (LP EGR). The object of study was the impact of charge air cooling on the engine working process at constant boundary conditions which could have been conducted with an available and validated engine model in AVL BOOST. Part load was realized with constant power and NOx-emissions, whereas full load was accomplished with a lambda control in order to obtain maximum engine performance. The informative results were used to implement a simulation model in Matlab/Simulink which is further integrated into a full vehicle simulation environment via coupling with ICOS (Independent Co-Simulation Platform). Next, the dynamic engine behavior was validated and modified with load steps taken from the engine test bed. Due to the modular setup in the Co-Simulation, different CAC-models have been simulated quickly with their different influences on the working process. In doing so, a new cooler variation isn’t needed to be reproduced and implemented into the primary simulation model environment, but is implemented quickly and easily as an independent component into the simulation entity. By means of the association of the engine model, longitudinal dynamics vehicle model and different CAC models (air/air & water/air variants) in both steady state and transient operational modes, statements are gained regarding fuel consumption, NOx-emissions and power behavior. The fact that there is no more need of a complex engine model is very advantageous for the overall simulation volume. Beside of the simulation with the mentioned demonstrator engine, there have also been conducted several experimental investigations on the engine test bench. Here the comparison of a standard CAC with an intake-manifold-integrated CAC was executed in particular. Simulative as well as experimental tests showed benefits for the water/air CAC variant (on test bed especially the intake manifold integrated variant). The benefits are illustrated by a reduced pressure loss and a gain in air efficiency and CAC efficiency, those who all lead to minimized emission and fuel consumption for stationary and transient operation.

Keywords: air/water-charge air cooler, co-simulation, diesel working process, EURO VI fuel consumption

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Authors: Zachary Muthii Rukenya, James Mbaria, Peter Mbaabu, Kiama Stephen Gitahi, Ronald Onzago

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Aloe turkanensis is one of the widely used medicinal shrub and in Kenya the plant is mainly found in Baringo, Isiolo, Laikipia, Turkana and West Pokot Counties where it is used in ethno-medicine and ethno-veterinary medicine. The Turkana community uses the plant products to manage malaria, wounds, stomach ache, constipation, pain, skin infection, poultry diseases and retained afterbirth in cows. This evaluated the efficacy and safety of the plant obtained from Turkana County, Kenya. Preliminary data on the use of the plant in the county was collected through observation, photographing and interviews. A sample of the whole plant was harvested in Natira sublocation, in ex-Turkana west district in February 2012 after identification by Aloe-working group herbalists who voluntarily provided information on its medicinal uses. Botanical identification was done at Kenya Forest Research Centre in Karura where voucher specimen was deposited. Cold maceration using 70% methanol and distilled water was used for extraction. Bioassays were to determine the effects of the plant extracts on brine shrimp and selected bacterial and fungal cultures. The extracts were tested in-vitro activity against standard cultures of B. cereus (ATCC 11778), S. aureus (ATCC25923), P. aeroginosa (ATCC 27853), E. coli (ATCC 25922) and a human infections clinical isolate of C. albicans. The extracts of Aloe turkanensis inhibited the growth B. cereus (100-200 mg/ml), S. aureus (50-100 mg/ml), P. aeroginosa (200mg/ml), E. coli (400mg/ml) while C. albicans was not affected. The extracts also inhibited the growth of S. aureus and B. cereus with mean diameters of inhibition zones being 19.75±1 mm and 18.5±05 mm reapectively. Phytochemical screening showed the presence of alkaloids, tarpenoids, steroids, quinones, saponins and tannins in the plant extracts. The extract was found to be non-toxic at a concentration of 1000µg/ml with a 100% survival of Brine Shrimp larva. It was concluded that Aloe turkanensis growing the study area has metabolites that inhibit the growth of microorganisms and is however, there is need for further studies to validate the in-vivo bioactivity of the plant and more generate adequate toxicological data.to support conservation, value chain addition of its products and widespread use as a herbal remedy.

Keywords: Aloe turkanensis, bioactivity, cultivated, human infections

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Authors: Mette Pedersen

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This paper outlines the criteria that assessment specialists use when they design the 'Persuasive Essay' task for the four Advanced Placement World Language and Culture Exams (AP French, German, Italian, and Spanish). The 'Persuasive Essay' is a free-response, source-based, standardized measure of presentational writing. Each 'Persuasive Essay' item consists of three sources (an article, a chart, and an audio) and a prompt, which is a statement of the topic phrased as an interrogative sentence. Due to its richness of source materials and due to the amount of time that test takers are given to prepare for and write their responses (a total of 55 minutes), the 'Persuasive Essay' is the free-response task on the AP World Language and Culture Exams that goes to the greatest lengths to unleash the test takers' proficiency potential. The author focuses on the work that goes into designing the 'Persuasive Essay' task, outlining best practices for the selection of topics and sources, the interplay that needs to be present among the sources and the thinking behind the articulation of prompts for the 'Persuasive Essay' task. Using released 'Persuasive Essay' items from the AP World Language and Culture Exams and accompanying data on test taker performance, the author shows how different passages, and features of passages, have succeeded (and sometimes not succeeded) in eliciting writing proficiency among test takers over time. Data from approximately 215.000 test takers per year from 2014 to 2017 and approximately 35.000 test takers per year from 2012 to 2013 form the basis of this analysis. The conclusion of the study is that test taker performance improves significantly when the sources that test takers are presented with express directly opposing viewpoints. Test taker performance also improves when the interrogative prompt that the test takers respond to is phrased as a yes/no question. Finally, an analysis of linguistic difficulty and complexity levels of the printed sources reveals that test taker performance does not decrease when the complexity level of the article of the 'Persuasive Essay' increases. This last text complexity analysis is performed with the help of the 'ETS TextEvaluator' tool and the 'Complexity Scale for Information Texts (Scale)', two tools, which, in combination, provide a rubric and a fully-automated technology for evaluating nonfiction and informational texts in English translation.

Keywords: advanced placement world language and culture exams, designing presentational writing assessments, large-scale standardized assessments of written language proficiency, source-based language testing

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Authors: Nibal Al-Batsh, Issam Al-Khatib, Subha Ghannam

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Yatta is the study area for this research, located 9 km south of Hebron City in the West Bank in Palestine. It has been connected to a water network since 1974 serving nearly 85% of the households. The water network is old and inadequate to meet the needs of the population. The water supply made available to the area is also very limited, estimated to be around 20 l/c.d. Residents are thus forced to rely on water vendors which supply water with a lower quality compared to municipal water while being 400% more expensive. As a cheaper and more reliable alternative, rainwater harvesting is a common practice in the area, with the majority of the households owning at least one cistern. Rainwater harvesting is of great socio-economic importance in areas where water sources are scarce or polluted. The quality of harvested rainwater used for drinking and domestic purposes in the Yatta area was assessed throughout a year long period. A total of 100 water samples were collected from (50 rainfed cisterns) with an average capacity of 69 m3, adjacent to cement-roof catchment with an average area of 145 m2. Samples were analyzed for a number of parameters including: pH, Alkalinity, Hardness, Turbidity, Total Dissolved Solids (TDS), NO3, NH4, chloride and salinity. Microbiological contents such as Total Coliforms (TC) and Fecal Coliforms (FC) bacteria were also analyzed. Results showed that most of the rainwater samples were within WHO and EPA guidelines set for chemical parameters while revealing biological contamination. The pH values of mixed water ranged from 6.9 to 8.74 with a mean value of 7.6. collected Rainwater had lower pH values than mixed water ranging from 7.00 to 7.57 with a mean of 7.21. Rainwater also had lower average values of conductivity (389.11 µScm-1) compared to that of mixed water (463.74 µScm-1) thus indicating lower values of salinity (0.75%). The largest TDS value measured in rainwater was 316 mg/l with a mean of 199.86 mg /l. As far as microbiological quality is concerned, TC and FC were detected in 99%, 52% of collected rainwater samples, respectively. The research also addressed the impact of different socio-economic attributes on rainwater harvesting using information collected through a survey from the area. Results indicated that the majority of homeowners have the primary knowledge necessary to collect and store water in cisterns. Most of the respondents clean both the cisterns and the catchment areas. However, the research also arrives at a conclusion that cleaning is not done in a proper manner. Results show that cisterns with an operating capacity of 69 m3 would provide sufficient water to get through the dry summer months. However, the catchment area must exceed 146 m2 to produce sufficient water to fill a cistern of this size in a year receiving average precipitation.

Keywords: rainwater harvesting, runoff coefficient, water quality, microbiological contamination

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Authors: Cesar Vazquez-Gonzalez, Sophie Avila-Foucat, Leonardo Ortiz-Lozano, Patricia Moreno-Casasola, Alejandro Granados-Barba

Abstract:

In the last twenty years, academic and scientific literature has been focused on understanding the processes and factors of coastal social-ecological systems vulnerability and resilience. Some scholars argue that resilience and vulnerability are isolated concepts due to their epistemological origin, while others note the existence of a strong resilience-vulnerability relationship. Here we present an ordinal logistic regression model based on the analytical framework about dynamic resilience-vulnerability interaction along adaptive cycle of complex systems and disasters process phases (during, recovery and learning). In this way, we demonstrate that 1) during the disturbance, absorptive capacity (resilience as a core of attributes) and external response capacity explain the probability of households capitals to diminish the damage, and exposure sets the thresholds about the amount of disturbance that households can absorb, 2) at recovery, absorptive capacity and external response capacity explain the probability of households capitals to recovery faster (resilience as an outcome) from damage, and 3) at learning, adaptive capacity (resilience as a core of attributes) explains the probability of households adaptation measures based on the enhancement of physical capital. As a result, during the disturbance phase, exposure has the greatest weight in the probability of capital’s damage, and households with absorptive and external response capacity elements absorbed the impact of floods in comparison with households without these elements. At the recovery phase, households with absorptive and external response capacity showed a faster recovery on their capital; however, the damage sets the thresholds of recovery time. More importantly, diversity in financial capital increases the probability of recovering other capital, but it becomes a liability so that the probability of recovering the household finances in a longer time increases. At learning-reorganizing phase, adaptation (modifications to the house) increases the probability of having less damage on physical capital; however, it is not very relevant. As conclusion, resilience is an outcome but also core of attributes that interacts with vulnerability along the adaptive cycle and disaster process phases. Absorptive capacity can diminish the damage experienced by floods; however, when exposure overcomes thresholds, both absorptive and external response capacity are not enough. In the same way, absorptive and external response capacity diminish the recovery time of capital, but the damage sets the thresholds in where households are not capable of recovering their capital.

Keywords: absorptive capacity, adaptive capacity, capital, floods, recovery-learning, social-ecological systems

Procedia PDF Downloads 131

Authors: Kusmartono, Siti Chuzaemi, Hartutik dan Mashudi

Abstract:

Two studies were conducted involving an in vitro (Expt 1) and in vivo (Expt 2) measurements. Expt 1. aimed to evaluate effects of adding CT extracts on gas production and efficiency of microbial protein synthesis (EMPS), Expt 2 aimed to evaluate effects of supplementing shrub/tree leaves as CT source on feed consumption, digestibility, N retention, body weight gain and dressing percentage of growing sheep fed on elephant grass (EG) as a basal diet.Ten shrub and tree leaves used as CT sources were wild sunflower (Tithonia diversifolia), mulberry (Morus macroura), cassava (Manihot utilissima), avicienna (Avicennia marina), calliandra (Calliandra calothyrsus), sesbania (Sesbania grandiflora), acacia (acacia vilosa), glyricidia (Glyricidia sepium), jackfruit (Artocarpus heterophyllus), moringa (Moringa oleifera). The treatments applied in Expt 1 were: T1=Elephant grass (60%)+concentrate (40%); T2 = T1 + CT (3% DM); T3= T2 + PEG; T4 = T1 + CT (3.5% DM); T5 = T4 + PEG; T6 = T1 + CT (4% DM) and T7 = T6 + PEG. Data obtained were analysed using Randomized Block Design. Statistical analyses showed that treatments significanty affected (P<0.05) total gas production and EMPS. The lowest values of total gas production (45.9 ml/500 mg DM) and highest value of EMPS (64.6 g/kg BOTR) were observed in the treatment T4 (3.5% CT from cassava leave extract). Based on this result it was concluded that this treatment was the best and was chosen for further investigation using in vivo method. The treatmets applied for in vivo trial were: T1 = EG (60%) + concentrate (40%); T2 = T1 + dried cassava leave (equivalent to 3.5% CT); T3 = T2 + PEG. 18 growing sheep aging of 8-9 months and weighing of 23.67kg ± 1.23 were used in Expt 2. Results of in vivo study showed that treatments significanty affected (P<0.05) nutrients intake and digestibility (DM, OM and CP). N retention for sheep receiving treatment T2 were significantly higher (P<0.05; 15.6 g/d) than T1 (9.1 g/d) and T3 (8.53 g/d). Similar results were obtained for daily weight gain where T2 were the highest (62.79 g/d), followed by T1 (51.9 g/d) and T3 (52.85 g/d). Dressing percentage of T2 was the highest (51.54%) followed by T1 (49.61%) and T3 (49.32%). It can be concluded that adding adding dried cassava leaves did not reduce palatability due to CT, but rather increased OM digestibility and hence feed consumption was improved. N retention was increased due to the action of CT in the cassava leaves and this may have explained a higher input of N into duodenum which was further led to higer daily weight gain and dressing percentage.

Keywords: in vitro gas production, sheep, shrub and tree leaves, condensed tannin

Procedia PDF Downloads 264