Search results for: Michael Brown
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 954

Search results for: Michael Brown

354 Combining Transcriptomics, Bioinformatics, Biosynthesis Networks and Chromatographic Analyses for Cotton Gossypium hirsutum L. Defense Volatiles Study

Authors: Ronald Villamar-Torres, Michael Staudt, Christopher Viot

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Cotton Gossypium hirsutum L. is one of the most important industrial crops, producing the world leading natural textile fiber, but is very prone to arthropod attacks that reduce crop yield and quality. Cotton cultivation, therefore, makes an outstanding use of chemical pesticides. In reaction to herbivorous arthropods, cotton plants nevertheless show natural defense reactions, in particular through volatile organic compounds (VOCs) emissions. These natural defense mechanisms are nowadays underutilized but have a very high potential for cotton cultivation, and elucidating their genetic bases will help to improve their use. Simulating herbivory attacks by mechanical wounding of cotton plants in greenhouse, we studied by qPCR the changes in gene expression for genes of the terpenoids biosynthesis pathway. Differentially expressed genes corresponded to higher levels of the terpenoids biosynthesis pathway and not to enzymes synthesizing particular terpenoids. The genes were mapped on the G. hirsutum L. reference genome; their global relationships inside the general metabolic pathways and the biosynthesis of secondary metabolites were visualized with iPath2. The chromatographic profiles of VOCs emissions indicated first monoterpenes and sesquiterpenes emissions, dominantly four molecules known to be involved in plant reactions to arthropod attacks. As a result, the study permitted to identify potential key genes for the emission of volatile terpenoids by cotton plants in reaction to an arthropod attack, opening possibilities for molecular-assisted cotton breeding in benefit of smallholder cotton growers.

Keywords: biosynthesis pathways, cotton, mechanisms of plant defense, terpenoids, volatile organic compounds

Procedia PDF Downloads 346
353 The Financial and Metallurgical Benefits of Niobium Grain Refined As-Rolled 460 MPa H-Beam to the Construction Industry in SE Asia

Authors: Michael Wright, Tiago Costa

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The construction industry in SE Asia has been relying on S355 MPa “as rolled” H-beams for many years now. It is an easily sourced, metallurgically simple, reliable product that all designers, fabricators and constructors are familiar with. However, as the Global demand to better use our finite resources gets stronger, the need for an as-rolled S460 MPa H-Beam is becoming more apparent. The Financial benefits of an “as-rolled” S460 MPa H-beam are obvious. The S460 MPa beam which is currently available and used is fabricated from rolled strip. However, making H-beam from 3 x 460 MPa strips requires costly equipment, valuable welding skills & production time, all of which can be in short supply or better used for other purposes. The Metallurgical benefits of an “as-rolled” S460 MPa H-beam are consistency in the product. Fabricated H-beams have inhomogeneous areas where the strips have been welded together - parent metal, heat affected zone and weld metal all in the one body. They also rely heavily on the skill of the welder to guarantee a perfect, defect free weld. If this does not occur, the beam is intrinsically flawed and could lead to failure in service. An as-rolled beam is a relatively homogenous product, with the optimum strength and ductility produced by delivering steel with as fine as possible uniform cross sectional grain size. This is done by cost effective alloy design coupled with proper metallurgical process control implemented into an existing mill’s equipment capability and layout. This paper is designed to highlight the benefits of bring an “as-rolled” S460 MPa H-beam to the construction market place in SE Asia, and hopefully encourage the current “as-rolled” H-beam producers to rise to the challenge and produce an innovative high quality product for the local market.

Keywords: fine grained, As-rolled, long products, process control, metallurgy

Procedia PDF Downloads 280
352 An Organocatalytic Construction of Vicinal Tetrasubstituted Stereocenters via Mannich Reaction of 2-Substituted Benzofuran-3-One with Isatin-Derived Ketimine

Authors: Koilpitchai Sivamuthuraman, Venkitasamy Kesavan

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3-substituted 3-amino-2-oxindole skeleton bearing adjacent tetrasubstituted stereogenic centers is of great importance because of these heterocyclic motifs possess a wide range of pharmacological activity. The catalytic asymmetric construction of multi functionalised heterocyclic compound with adjacent tetrasubstituted stereocenters is one of the most difficult tasks in organic synthesis. To date, the most straightforward methodologies have been developed for synthesis of chiral 3-substituted 3-amino-2-oxindoles through the addition of carbon nucleophiles to isatin-derived ketimines. However, only a few successful examples have been described for the assembly of vicinal tetrasubstituted stereocenters using isatin derived ketimines as electrophiles. On the other hand, 2,2-Disubstituted benzofuran-3(2H)-ones and related frameworks are characteristic of a quaternary stereogenic center at C2 position present in quite a number of natural products and bioactive Molecules.Despite the intensive efforts devoted for the construction of 2,2-Disubstituted Benzofuran-3[2H]-one, there are only a few asymmetric methods such as organocatalytic Michael addition and enantioselective halogenations were reported till now. Due to the biological importance of oxindole and benzofuran-3-one, it is proposed here with the synthesis of hybrid molecule containing tetrasubstituted stereo centers through asymmetric organocatalysis. The addition of 2-substituted Benzofuran-3-one(1a) to isatin-derived ketimines(2a) using a bifunctional organocatalyst(catalyst IV or V), leading to chiral heterocyclic compounds containing both 3-amino 2-oxindole and benzofurn-3-one bearing vicinal quaternary stereocenters with good yields and excellent enantioselectivity. The present study extends the scope of the catalytic asymmetric Mannich reaction with isatin-derived ketimines, providing a new class of amino oxindole derivatives having benzofuran-3-one.

Keywords: asymmetric synthesis, benzofuran-3-one, isatin-derived ketimines, quaternary stereocenters

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351 Laboratory Simulation of Subway Dynamic Stray Current Interference with Cathodically Protected Structures

Authors: Mohammad Derakhshani, Saeed Reza Allahkaram, Michael Isakani-Zakaria, Masoud Samadian, Hojat Sharifi Rasaey

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Dynamic stray currents tend to change their magnitude and polarity with time at their source which will create anodic and cathodic spots on a nearby interfered structure. To date, one of the biggest known dynamic stray current sources are DC traction systems. Laboratory simulation is a suitable method to apply theoretical principles in order to identify effective parameters in dynamic stray current influenced corrosion. Simulation techniques can be utilized for various mitigation methods applied in a small scales for selection of the most efficient method with regards to field applications. In this research, laboratory simulation of potential fluctuations caused by dynamic stray current on a cathodically protected structure was investigated. A lab model capable of generating DC static and dynamic stray currents and simulating its effects on cathodically protected samples were developed based on stray current induced (contact-less) polarization technique. Stray current pick-up and discharge spots on an influenced structure were simulated by inducing fluctuations in the sample’s stationary potential. Two mitigation methods for dynamic stray current interference on buried structures namely application of sacrificial anodes as preferred discharge point for the stray current and potentially controlled cathodic protection was investigated. Results showed that the application of sacrificial anodes can be effective in reducing interference only in discharge spot. But cathodic protection through potential controlling is more suitable for mitigating dynamic stray current effects.

Keywords: simulation, dynamic stray current, fluctuating potentials, sacrificial anode

Procedia PDF Downloads 276
350 The Implementation of Sexual and Reproductive Health Education Policy in Schools in Asia and Africa: A Scoping Review

Authors: Rhea Khosla, Victoria Tzortziou-Brown

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Introduction: Adolescent SRH has been neglected since the start of the millennium. Adolescents comprise 16% of the global population, with the largest proportion living in Asia (650 million). By late adolescence, individuals in these regions are likely to become sexually active, and thus they must understand their SRH rights. Many lack knowledge of SRH, using unreliable sources for such information. Sex education is necessary to standardize and inform sexual knowledge, which empowers adolescents to make informed SRH decisions. School is an appropriate environment for this, however, SRH education requires effective policy to enforce. Nonetheless, this issue remains of low political priority in Asia and Africa. Current literature on sex education policy in schools in these regions is scarce and tends to have broad aims. Thus, a scoping review was necessary. Methods: Literature searches were conducted in February 2023 using six databases, including grey literature databases (PubMed, Scopus, Embase, Web of Science, Google Scholar, Global Index Medicus), returning a total of 1537 unique articles. After screening titles, abstracts and full text, 17 articles remained. References of included articles were additionally searched, producing a further 7 articles, which then underwent thematic analysis Results: Most countries in Africa and Asia did not have studies on this topic. Studies derived data from interviews with key stakeholders and quantitative methods quantified questionnaire responses. Barriers were: policy/curriculum issues, societal opinions, teaching discomfort, and lack of educator training. Limitations were insufficient timing, inconsistent implementation, insufficient hours dedicated to teaching, education received late into schooling, and discrepancies between teachers, schools, and students about whether policies were being implemented. Discussion: Based on the existing limited evidence, a cultural shift to reduce stigma seems necessary, alongside teacher and student involvement in policy formulation with effective implementation monitoring and educator training.

Keywords: adolescent, Africa, Asia, education, sexual and reproductive health, policy

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349 The Role of Non-Native Plant Species in Enhancing Food Security in Sub-Saharan Africa

Authors: Thabiso Michael Mokotjomela, Jasper Knight

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Intensification of agricultural food production in sub-Saharan Africa is of paramount importance as a means of increasing the food security of communities that are already experiencing a range of environmental and socio-economic stresses. However, achieving this aim faces several challenges including ongoing climate change, increased resistance of diseases and pests, extreme environmental degradation partly due to biological invasions, land tenure and management practices, socio-economic developments of rural populations, and national population growth. In particular, non-native plant species tend to display greater adaptation capacity to environmental stress than native species that form important food resource base for human beings, thus suggesting a potential for usage to shift accordingly. Based on review of the historical benefits of non-native plant species in food production in sub-Saharan Africa, we propose that use of non-invasive, non-native plant species and/or the genetic modification of native species might be viable options for future agricultural sustainability in this region. Coupled with strategic foresight planning (e.g. use of biological control agents that suppress plant species’ invasions), the consumptive use of already-introduced non-native species might help in containment and control of possible negative environmental impacts of non-native species on native species, ecosystems and biodiversity, and soil fertility and hydrology. Use of non-native species in food production should be accompanied by low cost agroecology practices (e.g. conservation agriculture and agrobiodiversity) that may promote the gradual recovery of natural capital, ecosystem services, and promote conservation of the natural environment as well as enhance food security.

Keywords: food security, invasive species, agroecology, agrobiodiversity, socio-economic stresses

Procedia PDF Downloads 346
348 Defect Correlation of Computed Tomography and Serial Sectioning in Additively Manufactured Ti-6Al-4V

Authors: Bryce R. Jolley, Michael Uchic

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This study presents initial results toward the correlative characterization of inherent defects of Ti-6Al-4V additive manufacture (AM). X-Ray Computed Tomography (CT) defect data are compared and correlated with microscopic photographs obtained via automated serial sectioning. The metal AM specimen was manufactured out of Ti-6Al-4V virgin powder to specified dimensions. A post-contour was applied during the fabrication process with a speed of 1050 mm/s, power of 260 W, and a width of 140 µm. The specimen was stress relief heat-treated at 16°F for 3 hours. Microfocus CT imaging was accomplished on the specimen within a predetermined region of the build. Microfocus CT imaging was conducted with parameters optimized for Ti-6Al-4V additive manufacture. After CT imaging, a modified RoboMet. 3D version 2 was employed for serial sectioning and optical microscopy characterization of the same predetermined region. Automated montage capture with sub-micron resolution, bright-field reflection, 12-bit monochrome optical images were performed in an automated fashion. These optical images were post-processed to produce 2D and 3D data sets. This processing included thresholding and segmentation to improve visualization of defect features. The defects observed from optical imaging were compared and correlated with the defects observed from CT imaging over the same predetermined region of the specimen. Quantitative results of area fraction and equivalent pore diameters obtained via each method are presented for this correlation. It is shown that Microfocus CT imaging does not capture all inherent defects within this Ti-6Al-4V AM sample. Best practices for this correlative effort are also presented as well as the future direction of research resultant from this current study.

Keywords: additive manufacture, automated serial sectioning, computed tomography, nondestructive evaluation

Procedia PDF Downloads 118
347 Protective Effect of Diosgenin against Silica-Induced Tuberculosis in Rat Model

Authors: Williams A. Adu, Cynthia A. Danquah, Paul P. S. Ossei, Selase Ativui, Michael Ofori, James Asenso, George Owusu

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Background Silicosis is an occupational disease of the lung that is caused by chronic exposure to silica dust. There is a higher frequency of co-existence of silicosis with tuberculosis (TB), ultimately resulting in lung fibrosis and respiratory failure. Chronic intake of synthetic drugs has resulted in undesirable side effects. Diosgenin is a steroidal saponin that has been shown to exert a therapeutic effect on lung injury. Therefore, we investigated the ability of diosgenin to reduce the susceptibility of silica-induced TB in rats. Method Silicosis was induced by intratracheal instillation of 50 mg/kg crystalline silica in Sprague Dawley rats. Different doses of diosgenin (1, 10, and 100 mg/kg), Mycobacterium smegmatis and saline were administered for 30 days. Afterwards, 5 of the rats from each group were sacrificed, and the 5 remaining rats in each group, except the control, received Mycobacterium smegmatis. Treatment of diosgenin continued until the 50th day, and the rats were sacrificed at the end of the experiment. The result was analysed using a one-way analysis of variance (ANOVA) with a Graph-pad prism Result At a half-maximal inhibition concentration of 48.27 µM, diosgenin inhibited the growth of Mycobacterium smegmatis. There was a marked decline in the levels of immune cell infiltration and cytokines production. Lactate dehydrogenase and total protein levels were significantly reduced compared to control. There was an increase in the survival rate of the treatment group compared to the control. Conclusion Diosgenin ameliorated silica-induced pulmonary tuberculosis by declining the levels of inflammatory and pro-inflammatory cytokines and, in effect, significantly reduced the susceptibility of rats to pulmonary TB.

Keywords: silicosis, tuberculosis, diosgenin, fibrosis, crystalline silica

Procedia PDF Downloads 42
346 Detection and Expression of Peroxidase Genes in Trichoderma harzianum KY488466 and Its Response to Crude Oil Degradation

Authors: Michael Dare Asemoloye, Segun Gbolagade Jonathan, Rafiq Ahmad, Odunayo Joseph Olawuyi, D. O. Adejoye

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Fungi have potentials for degrading hydrocarbons through the secretion of different enzymes. Crude oil tolerance and degradation by Trichoderma harzianum was investigated in this study with its ability to produce peroxidase enzymes (LiP and MnP). Many fungal strains were isolated from rhizosphere of grasses growing on a crude oil spilled site, and the most frequent strain based on percentage incidence was further characterized using morphological and molecular characteristics. Molecular characterization was done through the amplification of Ribosomal-RNA regions of 18s (1609-1627) and 28s (287-266) using ITS1 and ITS4 combinations and it was identified using NCBI BLAST tool. The selected fungus was also subjected to an in-vitro tolerance test at crude oil concentrations of 5, 10, 15, 20 and 25% while 0% served as control. In addition, lignin peroxidase genes (lig1-6) and manganese peroxidase gene (mnp) were detected and expressed in this strain using RT-PCR technique, its peroxidase producing activities was also studied in aliquots (U/ml). This strain had highest incidence of 80%, it was registered in NCBI as Trichoderma harzianum asemoJ KY488466. The strain KY488466 responded to crude oil concentrations as it increase, the dose inhibition response percentage (DIRP) increased from 41.67 to 95.41 at 5 to 25 % crude oil concentrations. All the peroxidase genes are present in KY488466, and expressed with amplified 900-1000 bp through RT-PCR technique. In this strain, lig2, lig4 and mnp genes were over-expressed, lig 6 was moderately expressed, while none of the genes was under-expressed. The strain also produced 90±0.87 U/ml lignin peroxidase and 120±1.23 U/mil manganese peroxidase enzymes in aliquots. These results imply that KY488466 can tolerate and survive high crude oil concentration and could be exploited for bioremediation of oil-spilled soils, the produced peroxidase enzymes could also be exploited for other biotechnological experiments.

Keywords: crude oil, enzymes, expression, peroxidase genes, tolerance, Trichoderma harzianum

Procedia PDF Downloads 196
345 Illness Experience Without Illness: A Qualitative Study on the Lived Experience of Young Adults During the COVID-19 Pandemic

Authors: Gemma Postil, Claire Zanin, Michael Halpin, Caroline Ritter

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Illness experience research typically focuses on people that are living with a medical condition; however, the broad consequences of the COVID-19 pandemic are impacting those without the virus itself, as many experienced extensive lockdowns, social isolation, and distress. Drawing on conceptual work in the illness experience literature, we argue that policy and social changes tied to COVID-19 produce biographical disruptions. In this sense, we argue that the COVID-19 pandemic produces illness experience without illness, as the pandemic comprehensively impacts health and biography. This paper draws on 30 in-depth interviews with young adults living in Prince Edward Island (PEI), which were conducted as part of a larger project to understand how young adults navigate compliance with the COVID-19 pandemic. We then inductively analyzed the interviews with a constructivist grounded theory approach. Specifically, we demonstrate that young adults living in PEI during the COVID-19 pandemic experienced biographical disruptions throughout the pandemic despite not contracting the virus. First, we detail how some participants experience biographical acceleration, with the pandemic accelerating relationships, home buying, and career planning. Second, we demonstrate biographical stagnation, wherein participants report being unable to pursue major life milestones. Lastly, we describe biographical regression, wherein participants feel they are losing ground during the pandemic and are actively falling behind their peers. These findings provide the novel application of illness experience concepts to the context of the COVID-19 pandemic, contribute to work on illness experience and ambiguity, and extend Bury’s conceptualization of biographical disruption. In conclusion, we demonstrate that young adults experienced the biographical disruption expected from having COVID-19 without having an illness, highlighting the depth to which the pandemic affected young adults.

Keywords: illness experience, lived experience, biographical disruption, COVID-19, young adults

Procedia PDF Downloads 134
344 Magnetic Biomaterials for Removing Organic Pollutants from Wastewater

Authors: L. Obeid, A. Bee, D. Talbot, S. Abramson, M. Welschbillig

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The adsorption process is one of the most efficient methods to remove pollutants from wastewater provided that suitable adsorbents are used. In order to produce environmentally safe adsorbents, natural polymers have received increasing attention in recent years. Thus, alginate and chitosane are extensively used as inexpensive, non-toxic and efficient biosorbents. Alginate is an anionic polysaccharide extracted from brown seaweeds. Chitosan is an amino-polysaccharide; this cationic polymer is obtained by deacetylation of chitin the major constituent of crustaceans. Furthermore, it has been shown that the encapsulation of magnetic materials in alginate and chitosan beads facilitates their recovery from wastewater after the adsorption step, by the use of an external magnetic field gradient, obtained with a magnet or an electromagnet. In the present work, we have studied the adsorption affinity of magnetic alginate beads and magnetic chitosan beads (called magsorbents) for methyl orange (MO) (an anionic dye), methylene blue (MB) (a cationic dye) and p-nitrophenol (PNP) (a hydrophobic pollutant). The effect of different parameters (pH solution, contact time, pollutant initial concentration…) on the adsorption of pollutant on the magnetic beads was investigated. The adsorption of anionic and cationic pollutants is mainly due to electrostatic interactions. Consequently methyl orange is highly adsorbed by chitosan beads in acidic medium and methylene blue by alginate beads in basic medium. In the case of a hydrophobic pollutant, which is weakly adsorbed, we have shown that the adsorption is enhanced by adding a surfactant. Cetylpyridinium chloride (CPC), a cationic surfactant, was used to increase the adsorption of PNP by magnetic alginate beads. Adsorption of CPC by alginate beads occurs through two mechanisms: (i) electrostatic attractions between cationic head groups of CPC and negative carboxylate functions of alginate; (ii) interaction between the hydrocarbon chains of CPC. The hydrophobic pollutant is adsolubilized within the surface aggregated structures of surfactant. Figure c shows that PNP can reach up to 95% of adsorption in presence of CPC. At highest CPC concentrations, desorption occurs due to the formation of micelles in the solution. Our magsorbents appear to efficiently remove ionic and hydrophobic pollutants and we hope that this fundamental research will be helpful for the future development of magnetically assisted processes in water treatment plants.

Keywords: adsorption, alginate, chitosan, magsorbent, magnetic, organic pollutant

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343 The Effectiveness of Cognitive-Behavioral Group Therapy on Stress, Illness Anxiety and Obsessions-Compulsion Caused by the Coronavirus Crisis in Adolescent (14-18 Year olds) in Tehran, Iran

Authors: Maryam Mousavi Nik, Sara Pasandian

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The aim of the current research was to determine the effectiveness of Cognitive-Behavioral Group Therapy (G-CBT) on stress, illness anxiety and obsessions-compulsion caused by the coronavirus crisis in adolescents (14-18-Year-olds) in Tehran, Iran. This research was carried out in the form of a semi-experimental study with a control group and in the framework of a pre-test and post-test design for both experimental and control groups. The statistical population of this research consisted of all high schools in Tehran in 2022. The sample size includes 32 Adolescents (14-18-Year-olds) who were selected using a cluster sampling method, and then they were randomly replaced in two experimental (n=16) and control (n=16) groups. In this research, an adolescent stress questionnaire (ASQ-N) with an emphasis on the impact of Coronavirus, Coronavirus disease anxiety (CDAS) and The Children's Yale-Brown Obsessive Compulsive Symptom Scale (CY-BOCS) emphasis on the Coronavirus were used, and group therapy intervention with The cognitive-behavioral approach was conducted for 8 sessions of 90 minutes in the experimental group. The research data were analyzed by Multivariate analysis of covariance (MANCOVA) and covariance (ANCVA) tests. The results of multivariate covariance analysis showed that group therapy intervention with a cognitive-behavioral approach had a significant effect on at least one of the variables of stress, illness anxiety and obsession-compulsion at the level (P<0.01, F=94.772) in the post-test stage. Also, the results of covariance analysis of one variable showed that group therapy intervention with a cognitive-behavioral approach in the level of (P<0.01, F=106.377) stress, in the level of (P<0.01, F=48.147) disease anxiety and in the level (P>0.01, F=17.033) of obsession-compulsion had a significant effect in the post-test stage. The results showed that The treatment with GCBT can be effective in decreasing stress, illness anxiety and obsessions and compulsion caused by the coronavirus crisis in Adolescents (15-20-Year-olds) and may be considered as an alternative to either individual cognitive-behavioral therapy or medication.

Keywords: stress, disease anxiety, obsession-compulsion, coronavirus (Covid-19) crisis, and cognitive-behavioral therapy

Procedia PDF Downloads 44
342 Becoming Academic in the Entrepreneurial University: Researcher Identities and Research Impact Development

Authors: Victoria G. Mountford-Brown

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The concept of the Entrepreneurial University and emphasis on higher education institutions as both hives of innovation and as producers of future innovators accord special significance to the role of academic researchers in future economic and social prosperity. Researcher development in the UK has embedded an emphasis or ‘enterprise lens’ on developing the capabilities of researchers to support a stable economy whilst providing solutions to societal challenges. However, the notion of the ‘entrepreneurial university’ and what that represents to many academics is met with tension and (dis)engagement in the premises of the ‘knowledge economy’ or ‘academic capitalism.’ Set in a landscape of UK higher education wherein the increasing emphasis on research impact, coupled with increasing competition for scarce funding, has created a ‘climate of performativity’. This research seeks to better understand the ways in which academic identities are (re)constructed in the everyday experiences of doctoral (PGR) and early career researchers (ECRs) as they navigate what is referred to by some as the ‘academic hunger games’. These daily pressures and high expectations of success are part of the identity work PGRs/ECRs undergo. This is often fraught with tension and struggles to adapt to the research environment suggesting a reason for imposter phenomenon to be rife in academia – particularly (but not exclusively) in the early stages of development. This pilot study involves qualitative semi-structured exploratory interviews with a mixed gendered sample of participants from a variety of subject disciplines who have taken part in an intensive 3-day innovation and enterprise program for PGR and ECRs premised on developing personal and research impact. The research seeks to better understand the processes of identity formation of becoming academic and offers a commentary on the notions of ‘imposter phenomenon’ and the exchange and development of resources or capital needed to ‘play the game’ in academia in the context of the ‘entrepreneurial university’. It explores ongoing (re)constructions of what it means to be an academic and the different ways in which social identities may embody and challenge the development of entrepreneurial academic identities. As such, it aims to contribute to our understanding of the innovation ecosystem of academia and the prosperity of academic researchers.

Keywords: entreprenruial development, higher education, identities, researcher development

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341 Hydraulic Optimization of an Adjustable Spiral-Shaped Evaporator

Authors: Matthias Feiner, Francisco Javier Fernández García, Michael Arneman, Martin Kipfmüller

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To ensure reliability in miniaturized devices or processes with increased heat fluxes, very efficient cooling methods have to be employed in order to cope with small available cooling surfaces. To address this problem, a certain type of evaporator/heat exchanger was developed: It is called a swirl evaporator due to its flow characteristic. The swirl evaporator consists of a concentrically eroded screw geometry in which a capillary tube is guided, which is inserted into a pocket hole in components with high heat load. The liquid refrigerant R32 is sprayed through the capillary tube to the end face of the blind hole and is sucked off against the injection direction in the screw geometry. Its inner diameter is between one and three millimeters. The refrigerant is sprayed into the pocket hole via a small tube aligned in the center of the bore hole and is sucked off on the front side of the hole against the direction of injection. The refrigerant is sucked off in a helical geometry (twisted flow) so that it is accelerated against the hot wall (centrifugal acceleration). This results in an increase in the critical heat flux of up to 40%. In this way, more heat can be dissipated on the same surface/available installation space. This enables a wide range of technical applications. To optimize the design for the needs in various fields of industry, like the internal tool cooling when machining nickel base alloys like Inconel 718, a correlation-based model of the swirl-evaporator was developed. The model is separated into 3 subgroups with overall 5 regimes. The pressure drop and heat transfer are calculated separately. An approach to determine the locality of phase change in the capillary and the swirl was implemented. A test stand has been developed to verify the simulation.

Keywords: helically-shaped, oil-free, R-32, swirl-evaporator, twist-flow

Procedia PDF Downloads 87
340 Playing Safely: An Exploration of Irish Parental Attitudes Towards Risky Play and Its Impact on Play Opportunities for Children

Authors: Fiona Armstrong, David Gaul, Michael Barrett, Lorraine D'Arcy

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Playing is an instinctive and universal human behavior, is a child’s way of learning and an outlet for their innate need of activity. Risky play can be defined as any play that is thrilling or exciting involving the risk of injury. The benefits of risky play have been acknowledged as helping children to explore and conquer fears, develop confidence, reduce anxiety, and develop risk-management skills. Studies indicate that children learn sound judgment by assessing and confronting risks in relation to their own capabilities through exposure to carefully managed play experiences. Risky play has been associated with danger and increased risk of injury, with families focusing on risk aversion and protecting children from the risks inherent in the modern world. Despite children needing cultural, social, emotional, physical, and geographical space to play, the opportunity for children to play is diminishing. Aim: This study explores play behaviors and risky play in an Irish context by investigating parental attitudes to risky play. Methodology: This is a mixed methods study involving the State of Play survey and semi-structured interviews exploring parental attitudes to risky play. Data will be quantitatively analyzed using descriptive and inferential statistics using IBM SPSS and qualitatively analyzed via thematic analysis using NVivo. Conclusion: The information gathered could advise stakeholders regarding the creation and provision of developmentally appropriate, challenging, stimulating, adaptable, accessible, and safe as necessary outdoor play areas. This research can inform parents, planners, architects, and authorities involved in creating environments for play and contribute to policy development.

Keywords: child development, parental attitudes, play opportunities, risky play

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339 Different Motor Inhibition Processes in Action Selection Stage: A Study with Spatial Stroop Paradigm

Authors: German Galvez-Garcia, Javier Albayay, Javiera Peña, Marta Lavin, George A. Michael

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The aim of this research was to investigate whether the selection of the actions needs different inhibition processes during the response selection stage. In Experiment 1, we compared the magnitude of the Spatial Stroop effect, which occurs in response selection stage, in two motor actions (lifting vs reaching) when the participants performed both actions in the same block or in different blocks (mixed block vs. pure blocks).Within pure blocks, we obtained faster latencies when lifting actions were performed, but no differences in the magnitude of the Spatial Stroop effect were observed. Within mixed block, we obtained faster latencies as well as bigger-magnitude for Spatial Stroop effect when reaching actions were performed. We concluded that when no action selection is required (the pure blocks condition), inhibition works as a unitary system, whereas in the mixed block condition, where action selection is required, different inhibitory processes take place within a common processing stage. In Experiment 2, we investigated this common processing stage in depth by limiting participants’ available resources, requiring them to engage in a concurrent auditory task within a mixed block condition. The Spatial Stroop effect interacted with Movement as it did in Experiment 1, but it did not significantly interact with available resources (Auditory task x Spatial Stroop effect x Movement interaction). Thus, we concluded that available resources are distributed equally to both inhibition processes; this reinforces the likelihood of there being a common processing stage in which the different inhibitory processes take place.

Keywords: inhibition process, motor processes, selective inhibition, dual task

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338 MicroRNA-211 Regulates Oxidative Phosphorylation and Energy Metabolism in Human Vitiligoa

Authors: Anupama Sahoo, Bongyong Lee, Katia Boniface, Julien Seneschal, Sanjaya K. Sahoo, Tatsuya Seki, Chunyan Wang, Soumen Das, Xianlin Han, Michael Steppie, Sudipta Seal, Alain Taieb, Ranjan J. Perera

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Vitiligo is a common, chronic skin disorder characterized by loss of epidermal melanocytes and progressive depigmentation. Vitiligo has a complex immune, genetic, environmental, and biochemical etiology, but the exact molecular mechanisms of vitiligo development and progression, particularly those related to metabolic control, are poorly understood. Here we characterized the human vitiligo cell line PIG3V and the normal human melanocytes, HEM-l by RNA-sequencing, targeted metabolomics, and shotgun lipidomics. Melanocyte-enriched miR-211, a known metabolic switch in non-pigmented melanoma cells, was severely downregulated in vitiligo cell line PIG3V and skin biopsies from vitiligo patients, while its novel predicted targets transcriptional co-activator PGC1-α (PPARGC1A), ribonucleotide reductase regulatory subunit M2 (RRM2), and serine-threonine protein kinase TAO1 (TAOK1) were reciprocally upregulated. miR-211 binds to PGC1-α 3’UTR locus and represses it. Although mitochondrial numbers were constant, mitochondrial complexes I, II, and IV and respiratory responses were defective in vitiligo cells. Nanoparticle-coated miR-211 partially augmented the oxygen consumption rate in PIG3V cells. The lower oxygen consumption rate, changes in lipid and metabolite profiles, and increased reactive oxygen species production observed in vitiligo cells appear to be partly due to abnormal regulation of miR-211 and its target genes. These genes represent potential biomarkers and therapeutic targets in human vitiligo.

Keywords: metabolism, microRNA, mitochondria, vitiligo

Procedia PDF Downloads 337
337 Investigating the Use of Seaweed Extracts as Biopesticides

Authors: Emma O’ Keeffe, Helen Hughes, Peter McLoughlin, Shiau Pin Tan, Nick McCarthy

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Biosecurity is emerging as one of the most important issues facing the agricultural and forestry community. This is as a result of increased invasion from new pests and diseases with the main protocol for dealing with these species being the use of synthetic pesticides. However, these chemicals have been shown to exhibit negative effects on the environment. Seaweeds represent a vast untapped resource of bio-molecules with a broad range of biological activities including pesticidal. This project investigated both the antifungal and antibacterial activity of seaweed species against two problematic root rot fungi, Armillaria mellea and Heterobasidion annosum and ten quarantine bacterial plant pathogens including Xanthomonas arboricola, Xanthomonas fragariae, and Erwinia amylovora. Four seaweed species were harvested from the South-East coast of Ireland including brown, red and green varieties. The powdered seaweeds were extracted using four different solvents by liquid extraction. The poisoned food technique was employed to establish the antifungal efficacy, and the standard disc diffusion assay was used to assess the antibacterial properties of the seaweed extracts. It was found that extracts of the green seaweed exhibited antifungal activity against H. annosum, with approximately 50% inhibition compared to the negative control. The protectant activities of the active extracts were evaluated on disks of Picea sitchensis, a plant species sensitive to infection from H. annosum and compared to the standard chemical control product urea. The crude extracts exhibited very similar activity to the 10% and 20% w/v concentrations of urea, demonstrating the ability of seaweed extracts to compete with commercially available products. Antibacterial activity was exhibited by a number of seaweed extracts with the red seaweed illustrating the strongest activity, with a zone of inhibition of 15.83 ± 0.41 mm exhibited against X. arboricola whilst the positive control (10 μg/disk of chloramphenicol) had a zone of 26.5 ± 0.71 mm. These results highlight the potential application of seaweed extracts in the forestry and agricultural industries for use as biopesticides. Further work is now required to identify the bioactive molecules that are responsible for this antifungal and antibacterial activity in the seaweed extracts, including toxicity studies to ensure the extracts are non-toxic to plants and humans.

Keywords: antibacterial, antifungal, biopesticides, seaweeds

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336 Teaching Practices for Subverting Significant Retentive Learner Errors in Arithmetic

Authors: Michael Lousis

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The systematic identification of the most conspicuous and significant errors made by learners during three-years of testing of their progress in learning Arithmetic throughout the development of the Kassel Project in England and Greece was accomplished. How much retentive these errors were over three-years in the officially provided school instruction of Arithmetic in these countries has also been shown. The learners’ errors in Arithmetic stemmed from a sample, which was comprised of two hundred (200) English students and one hundred and fifty (150) Greek students. The sample was purposefully selected according to the students’ participation in each testing session in the development of the three-year project, in both domains simultaneously in Arithmetic and Algebra. Specific teaching practices have been invented and are presented in this study for subverting these learners’ errors, which were found out to be retentive to the level of the nationally provided mathematical education of each country. The invention and the development of these proposed teaching practices were founded on the rationality of the theoretical accounts concerning the explanation, prediction and control of the errors, on the conceptual metaphor and on an analysis, which tried to identify the required cognitive components and skills of the specific tasks, in terms of Psychology and Cognitive Science as applied to information-processing. The aim of the implementation of these instructional practices is not only the subversion of these errors but the achievement of the mathematical competence, as this was defined to be constituted of three elements: appropriate representations - appropriate meaning - appropriately developed schemata. However, praxis is of paramount importance, because there is no independent of science ‘real-truth’ and because praxis serves as quality control when it takes the form of a cognitive method.

Keywords: arithmetic, cognitive science, cognitive psychology, information-processing paradigm, Kassel project, level of the nationally provided mathematical education, praxis, remedial mathematical teaching practices, retentiveness of errors

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335 Ensuring Safe Operation by Providing an End-To-End Field Monitoring and Incident Management Approach for Autonomous Vehicle Based on ML/Dl SW Stack

Authors: Lucas Bublitz, Michael Herdrich

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By achieving the first commercialization approval in San Francisco the Autonomous Driving (AD) industry proves the technology maturity of the SAE L4 AD systems and the corresponding software and hardware stack. This milestone reflects the upcoming phase in the industry, where the focus is now about scaling and supervising larger autonomous vehicle (AV) fleets in different operation areas. This requires an operation framework, which organizes and assigns responsibilities to the relevant AV technology and operation stakeholders from the AV system provider, the Remote Intervention Operator, the MaaS provider and regulatory & approval authority. This holistic operation framework consists of technological, processual, and organizational activities to ensure safe operation for fully automated vehicles. Regarding the supervision of large autonomous vehicle fleets, a major focus is on the continuous field monitoring. The field monitoring approach must reflect the safety and security criticality of incidents in the field during driving operation. This includes an automatic containment approach, with the overall goal to avoid safety critical incidents and reduce downtime by a malfunction of the AD software stack. An End-to-end (E2E) field monitoring approach detects critical faults in the field, uses a knowledge-based approach for evaluating the safety criticality and supports the automatic containment of these E/E faults. Applying such an approach will ensure the scalability of AV fleets, which is determined by the handling of incidents in the field and the continuous regulatory compliance of the technology after enhancing the Operational Design Domain (ODD) or the function scope by Functions on Demand (FoD) over the entire digital product lifecycle.

Keywords: field monitoring, incident management, multicompliance management for AI in AD, root cause analysis, database approach

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334 Insight into the Visual Attentional Correlates Underpinning Autistic-Like Traits in Fragile X and Down Syndrome

Authors: Jennifer M. Glennon, Hana D'Souza, Luke Mason, Annette Karmiloff-Smith, Michael S. C. Thomas

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Genetic syndrome groups that feature high rates of autism comorbidity, like Down syndrome (DS) and fragile X syndrome (FXS), have been presented as useful models for understanding risk and protective factors involved in the emergence of autistic traits. Yet despite reaching clinical thresholds, these ‘syndromic’ forms of autism appear to differ in important ways from the idiopathic or ‘non-syndromic’ autism phenotype. To uncover the true nature of these comorbidities, it is necessary to extend definitions of autism to include the cognitive characteristics of the disorder and to then apply this broadened conceptualisation to the study of syndromic autism profiles. The current study employs a variety of well-established eye-tracking paradigms to assess visual attentional performance in children with DS and FXS who reach thresholds for autism on the Social Communication Questionnaire. It investigates whether autism profiles in these children are accompanied by visual orienting difficulties (‘sticky attention’), decreased social attention, and enhanced visual search performance, all of which are characteristic of the idiopathic autism phenotype. Data is collected from children with DS and FXS aged between 6 and 10 years, in addition to two control groups matched on age and intellectual ability (i.e., children with idiopathic autism and neurotypical controls). Cross-sectional developmental trajectory analyses are conducted to enable visuo-attentional profile comparisons. Significant differences in the visuo-attentional processes underpinning autism presentations in children with FXS and DS are hypothesised, supporting notions of syndrome specificity. The study provides insight into the complex heterogeneity associated with syndromic autism presentations and autism per se, with clinical implications for the utility of autism intervention programmes in DS and FXS populations.

Keywords: autism, down syndrome, fragile X syndrome, eye tracking

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333 The Impact of Dispatching with Rolling Horizon Control in Sizing Thermal Storage for Solar Tower Plant Participating in Wholesale Spot Electricity Market

Authors: Navid Mohammadzadeh, Huy Truong-Ba, Michael Cholette

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The solar tower (ST) plant is a promising technology to exploit large-scale solar irradiation. With thermal energy storage, ST plant has the potential to shift generation to high electricity price periods. However, the size of storage limits the dispatchability of the plant, particularly when it should compete with uncertainty in forecasts of solar irradiation and electricity prices. The purpose of this study is to explore the size of storage when Rolling Horizon Control (RHC) is employed for dispatch scheduling. To this end, RHC is benchmarked against perfect knowledge (PK) forecast and two day-ahead dispatching policies. With optimisation of dispatch planning using PK policy, the optimal achievable profit for a specific size of the storage is determined. A sensitivity analysis using Monte-Carlo simulation is conducted, and the size of storage for RHC and day-ahead policies is determined with the objective of reaching the profit obtained from the PK policy. A case study is conducted for a hypothetical ST plant with thermal storage located in South Australia and intends to dispatch under two market scenarios: 1) fixed price and 2) wholesale spot price. The impact of each individual source of uncertainty on storage size is examined for January and August. The exploration of results shows that dispatching with RH controller reaches optimal achievable profit with ~15% smaller storage compared to that in day-ahead policies. The results of this study may be applied to the CSP plant design procedure.

Keywords: solar tower plant, spot market, thermal storage system, optimized dispatch planning, sensitivity analysis, Monte Carlo simulation

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332 Effects of Lateness Gene on Yield and Related Traits in Indica Rice

Authors: B. B. Rana, M. Yokota, Y. Shimizu, Y. Koide, I. Takamure, T. Kawano, M. Murai

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Various genes which control or affect heading time have been found in rice. Out of them, Se1 and E1 loci play important roles in determining heading time by controlling photosensitivity. An isogenic-line pair of late and early lines were developed from progenies of the F1 from Suweon 258 × 36U. A lateness gene tentatively designated as “Ex” was found to control the difference in heading time between the early and late lines mentioned above. The present study was conducted to examine the effect of Ex on yield and related traits. Indica-type variety Suweon 258 was crossed with 36U, which is an Ur1 (Undulate rachis-1) isogenic line of IR36. In the F2 population, comparatively early-heading, late-heading and intermediate-heading plants were segregated. Segregation similar to that by the three types of heading was observed in the F3 and later generations. A late-heading plant and an early-heading plant were selected in the F8 population from an intermediate-heading F7 plant, for developing L and E of the isogenic-line pair, respectively. Experiments for L and E were conducted by randomized block design with three replications. Transplanting was conducted on May 3 at a planting distance of 30 cm × 15 cm with two seedlings per hill to an experimental field of the Faculty of Agriculture, Kochi University. Chemical fertilizers containing N, P2O5 and K2O were applied at the nitrogen levels of 4 g/m2, 9 g/m2 and 18 g/m2 in total being denoted by "N4", "N9" and "N18", respectively. Yield, yield components and other traits were measured. Ex delayed 80%-heading by 17 or 18 days in L as compared with E. In total brown rice yield (g/m2), L was 635, 606 and 590, and E was 577, 548 and 501, respectively, at N18, N9 and N4, indicating that Ex increased this trait by 10% to 18%. Ex increased yield-1.5 mm sieve (g/m2) b 9% to 15% at the three fertilizer levels. Ex increased the spikelet number per panicle by 16% to 22%. As a result, the spikelet number per m2 was increased by 11% to 18% at the three fertilizer levels. Ex decreased 1000-grain weight (g) by 2 to 4%. L was not significantly different from E in ripened-grain percentage, fertilized-spikelet percentage and percentage of ripened grains to fertilized spikelets. Hence, it is inferred that Ex increased yield by increasing spikelet number per panicle. Hence, Ex could be utilized to develop high yielding varieties for warmer districts.

Keywords: heading time, lateness gene, photosensitivity, yield, yield components

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331 Comparison of Various Landfill Ground Improvement Techniques for Redevelopment of Closed Landfills to Cater Transport Infrastructure

Authors: Michael D. Vinod, Hadi Khabbaz

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Construction of infrastructure above or adjacent to landfills is becoming more common to capitalize on the limited space available within urban areas. However, development above landfills is a challenging task due to large voids, the presence of organic matter, heterogeneous nature of waste and ambiguity surrounding landfill settlement prediction. Prior to construction of infrastructure above landfills, ground improvement techniques are being employed to improve the geotechnical properties of landfill material. Although the ground improvement techniques have little impact on long term biodegradation and creep related landfill settlement, they have shown some notable short term success with a variety of techniques, including methods for verifying the level of effectiveness of ground improvement techniques. This paper provides geotechnical and landfill engineers a guideline for selection of landfill ground improvement techniques and their suitability to project-specific sites. Ground improvement methods assessed and compared in this paper include concrete injected columns (CIC), dynamic compaction, rapid impact compaction (RIC), preloading, high energy impact compaction (HEIC), vibro compaction, vibro replacement, chemical stabilization and the inclusion of geosynthetics such as geocells. For each ground improvement technique a summary of the existing theory, benefits, limitations, suitable modern ground improvement monitoring methods, the applicability of ground improvement techniques for landfills and supporting case studies are provided. The authors highlight the importance of implementing cost-effective monitoring techniques to allow observation and necessary remediation of the subsidence effects associated with long term landfill settlement. These ground improvement techniques are primarily for the purpose of construction above closed landfills to cater for transport infrastructure loading.

Keywords: closed landfills, ground improvement, monitoring, settlement, transport infrastructure

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330 Moulding Photovoice to Community: Supporting Aboriginal People Experiencing Homelessness to Share Their Stories through Photography

Authors: Jocelyn Jones, Louise Southalan, Lindey Andrews, Mandy Wilson, Emma Vieira, Jackie Oakley, Dorothy Bagshaw, Alice V. Brown, Patrick Egan, Duc Dau, Lucy Spanswick

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Working with people experiencing homelessness requires careful use of methods that support them to comfortably share their experiences. This is particularly important for Aboriginal and Torres Strait Islander peoples, the traditional owners of Australia, who have experienced intergenerational and compounding trauma since colonisation. Aboriginal cultures regularly experience research fatigue and distrust in research’s potential for impact. They often view research as an extraction -a process of taking the knowledge that empowers the research team and its institution, rather than benefiting those being researched. Through a partnership between an Aboriginal Community Controlled Organisation and a university research institute, we conducted a community-driven research project with 70-90 Aboriginal people experiencing homelessness in Perth, Western Australia. The project aimed to listen to and advocate for the voices of those who are experiencing homelessness, guided by the Aboriginal community. In consultation with Aboriginal Elders, we selected methods that are considered culturally safe, including those who would prefer to express their experiences creatively. This led us to run a series of Photovoice workshops -an established method that supports people to share their experiences through photography. This method treats participants as experts and is regularly used with marginalised groups across the world. We detail our experience and lessons in using Photovoice with Aboriginal community members experiencing homelessness. This includes the ways the method needed to be moulded to community needs and driven by their individual choices, such as being dynamic in the length of time participants would spend with us, how we would introduce the method to them, and providing support workers for participants when taking photos. We also discuss lessons in establishing and retaining engagement and how the method was successful in supporting participants to comfortably share their stories. Finally, we outline the insights into homelessness that the method offered, including highlighting the difficulty experienced by participants in transitioning from homelessness to accommodation and the diversity of hopes people who have experienced homelessness have for the future.

Keywords: Aboriginal and Torres Strait Islander peoples, photovoice, homelessness, community-led research

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329 The Importance of Elders in Guiding Research and Findings for Aboriginal People Experiencing Homelessness

Authors: Alice V. Brown, Patrick Egan, Dorothy Bagshaw, Jackie Oakley, Emma Vieira, Louise Southalan, Duc Dau, Lucy Spanswick, Lindey Andrews, Mandy Wilson, Jocelyn Jones

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Western Australia has recently adopted a 10-year plan to end homelessness across its State, with sections of the plan focused particularly on the Aboriginal and Torres Strait Islander population. In 2022, we engaged with 70-90 Aboriginal people experiencing homelessness in Perth, Western Australia, through qualitative interviews and creative methods, listening to their experiences of homelessness and their views on how services, State plans, and policies could better support them. This research was driven by the Aboriginal community through a Community Ownership Group of 16 Aboriginal Elders, elected by Elders’ groups, from across the Perth metropolitan area. The Community Ownership Group met every six weeks across the 15-month project timeline to guide the research team, endorse methods chosen, and provide richer context to research findings to ensure they adequately represent the experiences of Aboriginal people. These meetings were audio-recorded when possible and documented through meeting notes, verbal and visual minutes, and film, providing insights into homelessness from the perspective of Aboriginal Elders. In this paper, we compare the views of those experiencing homelessness with the views of the Aboriginal Elders -many of whom have experienced homelessness firsthand- and literature regarding how those experiencing homelessness can be better supported. We detail the ‘survival-directed thinking’ of those we engaged with who was in the throes of homelessness, leading them to focus more on immediate solutions such as food and housing. We then compare these narratives to Elders’ views that have been more regularly focused on connection to culture and long-term plans for healing homelessness, alongside immediate outreach -views also reflected in the literature. Through these comparisons, we highlight the importance of engaging both with those currently experiencing homelessness as well as with Aboriginal Elders as important cultural caretakers and authorities. We demonstrate how these varied voices uncover both long and short-term perspectives on how homelessness can be better managed in policy and service provision. We also highlight the potential role Aboriginal Elders can play in supporting the Aboriginal homeless community and their transition into housing.

Keywords: Aboriginal and Torres strait islander peoples, aboriginal elders, homelessness, community-led research

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328 The English as a Foreign Language Teachers’ Perceptions and Practices of Infusing Critical Thinking Skills to Improve Students’ Reading Comprehension

Authors: Michael Amale Kirko, Abebe Gebretsadik

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In the 21st century, developing students’ critical thinking skills has become a prime concern in higher education institutions. Cognizant of this fact, the Ethiopian higher education policy document used critical thinking as one of the guiding principles. The study aims to explore how English as a foreign language (EFL) teachers perceive and practice critical thinking skills (CTS) in teaching reading to improve reading comprehension at Wolaita Sodo University, Ethiopia. A descriptive survey study used an exploratory mixed-methods approach. The study involved 20 EFL instructors and 40 2nd-year English majoring students. The numerical data were collected using teacher and student surveys and classroom observations; the qualitative data were obtained through content analysis and interviews. Teacher survey results indicated that teachers' perceptions are above average (mean = 3.41). And the result of classroom observations showed the practice CTS in class was below average (mean=2.61). The content analysis result revealed instructors utilized fewer higher-order thinking questions during class activities, quizzes, midterm, and final exams. The teachers perceived that teacher, student, and material-related challenges were hindering the practice of CT to improve students’ reading comprehension. Finally, spearman’s rho output showed r=0.97 and p<0.05. Therefore, the results showed that the EFL teachers’ practices of CTS to improve students’ reading comprehension were less frequent; there was a strong, positive, and statistically significant relationship between the teachers’ perceptions and practices of CTS in reading class.

Keywords: perceptions, critical thinking skills, practices, infusing thinking skills, reading comprehension

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327 Track and Evaluate Cortical Responses Evoked by Electrical Stimulation

Authors: Kyosuke Kamada, Christoph Kapeller, Michael Jordan, Mostafa Mohammadpour, Christy Li, Christoph Guger

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Cortico-cortical evoked potentials (CCEP) refer to responses generated by cortical electrical stimulation at distant brain sites. These responses provide insights into the functional networks associated with language or motor functions, and in the context of epilepsy, they can reveal pathological networks. Locating the origin and spread of seizures within the cortex is crucial for pre-surgical planning. This process can be enhanced by employing cortical stimulation at the seizure onset zone (SOZ), leading to the generation of CCEPs in remote brain regions that may be targeted for disconnection. In the case of a 24-year-old male patient suffering from intractable epilepsy, corpus callosotomy was performed as part of the treatment. DTI-MRI imaging, conducted using a 3T MRI scanner for fiber tracking, along with CCEP, is used as part of an assessment for surgical planning. Stimulation of the SOZ, with alternating monophasic pulses of 300µs duration and 15mA current intensity, resulted in CCEPs on the contralateral frontal cortex, reaching a peak amplitude of 206µV with a latency of 31ms, specifically in the left pars triangularis. The related fiber tracts were identified with a two-tensor unscented Kalman filter (UKF) technique, showing transversal fibers through the corpus callosum. The CCEPs were monitored through the progress of the surgery. Notably, the SOZ-associated CCEPs exhibited a reduction following the resection of the anterior portion of the corpus callosum, reaching the identified connecting fibers. This intervention demonstrated a potential strategy for mitigating the impact of intractable epilepsy through targeted disconnection of identified cortical regions.

Keywords: CCEP, SOZ, Corpus callosotomy, DTI

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326 Examining Neo-colonialism and Power in Global Surgical Missions: An Historical, Practical and Ethical Analysis

Authors: Alex Knighton, Roba Khundkar, Michael Dunn

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Neo-colonialism is defined as the use of economic, political, cultural, or other pressures to control or influence other countries, especially former dependencies, and concerns have been raised about its presence in surgical missions. Surgical missions aim to rectify the huge disparity in surgical access worldwide, but their ethics must be carefully considered. This is especially in light of colonial history which affects international relations and global health today, to ensure that colonial attitudes are not influencing efforts to promote equity. This review examines the history of colonial global health, demonstrating that global health initiatives have consistently been used to benefit those providing them, and then asks whether elements of colonialism are still pervasive in surgical missions today. Data was collected from the literature using specified search terms and snowball searching, as well as from international expert web-based conferences on global surgery ethics. A thematic analysis was then conducted on this data, resulting in the identification of six themes which are identifiable in both past and present global health initiatives. These six themes are power, lack of understanding or respect, feelings of superiority, exploitation, enabling of dependency, and acceptance of poorer standards of care. An ethical analysis follows, concluding that the concerns of power and neo-colonialism in global surgery would be addressed by adopting a framework of procedural justice that promotes a refined governance process in which stakeholders are able to propose and reject decisions that affect them. The paper argues that adopting this model would address concerns of the power disparity in the field directly, as well as promoting an ethical framework to enable the other concerns of power disparity and neo-colonialism identified in the present analysis to be addressed.

Keywords: medical ethics, global surgery, global health, neocolonialism, surgical missions

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325 Systematic Review and Meta-Analysis of Mid-Term Survival, and Recurrent Mitral Regurgitation for Robotic-Assisted Mitral Valve Repair

Authors: Ramanen Sugunesegran, Michael L. Williams

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Over the past two decades surgical approaches for mitral valve (MV) disease have evolved with the advent of minimally invasive techniques. Robotic mitral valve repair (RMVr) safety and efficacy has been well documented, however, mid- to long-term data are limited. The aim of this review was to provide a comprehensive analysis of the available mid- to long-term term data for RMVr. Electronic searches of five databases were performed to identify all relevant studies reporting minimum 5-year data on RMVr. Pre-defined primary outcomes of interest were overall survival, freedom from MV reoperation and freedom from moderate or worse mitral regurgitation (MR) at 5-years or more post-RMVr. A meta-analysis of proportions or means was performed, utilizing a random effects model, to present the data. Kaplan-Meier curves were aggregated using reconstructed individual patient data. Nine studies totaling 3,300 patients undergoing RMVr were identified. Rates of overall survival at 1-, 5- and 10-years were 99.2%, 97.4% and 92.3%, respectively. Freedom from MV reoperation at 8-years post RMVr was 95.0%. Freedom from moderate or worse MR at 7-years was 86.0%. Rates of early post-operative complications were low with only 0.2% all-cause mortality and 1.0% cerebrovascular accident. Reoperation for bleeding was low at 2.2% and successful RMVr was 99.8%. Mean intensive care unit and hospital stay were 22.4 hours and 5.2 days, respectively. RMVr is a safe procedure with low rates of early mortality and other complications. It can be performed with low complication rates in high volume, experienced centers. Evaluation of available mid-term data post-RMVr suggests favorable rates of overall survival, freedom from MV reoperation and freedom from moderate or worse MR recurrence.

Keywords: mitral valve disease, mitral valve repair, robotic cardiac surgery, robotic mitral valve repair

Procedia PDF Downloads 63