Search results for: Jean Marie Dembele
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 460

Search results for: Jean Marie Dembele

220 A Case Study on the Census of Technological Capacities in Health Care in Rural Sanitary Institutions in South Cameroon

Authors: Doriane Micaela Andeme Bikoro, Samuel Fosso Wamba, Jean Robert Kala Kamdjoug

Abstract:

Currently one of the leading fields in the market of technological innovation is digital health. In developed countries, this booming innovation is experiencing an exponential speed. We understand that in developed countries, e-health could also revolutionize the practice of medicine and therefore fill the many failures observed in medical care. Everything leads to believe that future technology is oriented towards the medical sector. The aim of this work is to explore at the same time the technological resources and the potential of health care based on new technologies; it is a case study in a rural area of Southern Cameroon. Among other things, we will make a census of the shortcomings and problems encountered, and we will propose various appropriate solutions. The work methodology used here is essentially qualitative. We used two qualitative data collection techniques, direct observation, and interviews. In fact, we spent two weeks in the field observing and conducting some semi-directive interviews with some of those responsible for these health structures. This study was conducted in three health facilities in the south of the country; including two health centers and a rural hospital. Many technological failures have been identified in the day-to-day management of these health facilities and especially in the administration of health care to patients. We note major problems such as the digital divide, the lack of qualified personnel, the state of isolation of this area. This is why various proposals are made to improve the health sector in Cameroon both technologically and medically.

Keywords: Cameroon, capacities, census, digital health, qualitative method, rural area

Procedia PDF Downloads 124
219 A Caged Bird Set Free: The Women Saviors in Fae Myenne Ng's Steer Toward Rock

Authors: Hei Yuen Pak

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Steer Toward Rock, Fae Myenne Ng’s second novel after the National Bestseller Bone, is superficially concluded as a story of pessimism, which underestimates the sophistication of Ng’s portrayal. It is often summarized as a “heartbreaking novel of unrequited love” or “a story of timeless and tragic”; yet, Ng’s novel conveys more than a mere sense of tragedy and heartbreak, but rather an overflowing warmth and optimism. Ng is complimented of “illuminating a part of U.S. history few are aware of”—the false identity established on the paper relationships. Nevertheless, toward the end of the novel, this falsity enlightens the male protagonist, Jack Moon Szeto, of the ultimate realization of the “truthfulness” to himself, with the escort of the female characters. This paper intends to investigate how Ng’s depiction subverts the traditional sex/gender system and also the patriarchal savior stereotype. This paper mainly examines the characterization of and the relations among the four major characters: Jack Moon Szeto, Joice Qwan, Veda Qwan, and Ilin Cheung. By deploying Kate Millett’s, Marilyn French’s, Mary Daly’s feminist theories, the first half of the essay elucidates the power relations between Jack and the three females Joice, Veda, and Ilin in terms of gender and sexuality. After analyzing the relations, Jack, this male caged bird, is set free by the epiphany derived from the three female characters, which is the pivot of the second half. In reference to Jean-Paul Sartre and Simone de Beauvoir’s existentialist perspectives, I argue how Jack is transformed from, in Satre’s term, being-for-others to being-for-itself. Hence, the caged bird is free by the women saviors.

Keywords: Fae Myenne Ng, gender and sexuality, feminism, power relations

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218 Hidden Populations and Women: New Political, Methodological and Ethical Challenges

Authors: Renée Fregosi

Abstract:

The contribution presently proposed will report on the beginnings of a Franco-Chilean study to be launched in 2015 by a multidisciplinary team of Renée Fregosi Political Science University Paris 3 / CECIEC, Norma Muñoz Public Policies University of Santiago of Chile, Jean-Daniel Lelievre, Medicine Paris 11 University, Marcelo WOLFF Medicine University of Chile, Cecilia Blatrix Political Science University Paris-Tech, Ernesto OTTONE, Political Science University of Chile, Paul DENY Medicine Paris 13 University, Rafael Bugueno Medicine Hospital Urgencia Pública of Santiago, Eduardo CARRASCO Political Science Paris 3 University. The problem of hidden populations challenges some criteria and concepts to re-examine: in particular the concept of target population, sampling methods to "snowball" and the cost-effectiveness criterion that shows the connection of political and scientific fields. Furthermore, if the pattern of homosexual transmission still makes up the highest percentage of the modes of infection with HIV, there is a continuous increase in the number of people infected through heterosexual sex, including women and persons aged 50 years and older. This group can be described as " unknown risk people." Access to these populations is a major challenge and raises methodological, ethical and political issues of prevention, particularly on the issue of screening. This paper proposes an inventory of these types of problems and their articulation, to define a new phase in the prevention against HIV refocused on women.

Keywords: HIV testing, hidden populations, difficult to reach PLWHA, women, unknown risk people

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217 The Effect of Projecting the Reflection of the Individual's Self-Esteem (PRIDE) Therapy on the Level of Self-Esteem of Physically Challenged Adolescents

Authors: Khiara Claudine C. Carbonel, Patricia Joy A. Canapi, Tracy Gabriella M. Canlas, Teresa Zaine C. Canseco, Reena Marie A. Capistrano, Vernon A. Carandang, Carlo G. Ranoco

Abstract:

Research problem: The main problem of the study was to determine the effect of Projecting the Reflection of the Individual’s Self-esteem (PRIDE) therapy on the level of self-esteem of physically challenged adolescents. Objectives of the Study: The study determined the effect of PRIDE (Projecting the Reflection of the Individuals Self-esteem) therapy on the level of self-esteem among physically challenged adolescents. Methodology: A quasi-experimental study was used which involved 30 randomly-assigned subjects, 15 in the experimental group and 15 in the control group. The Projecting the reflection of the Individuals’ Self-Esteem (PRDIE) therapy was administered to the experimental group. The researchers utilized the Sorensen Self-Esteem test tool as a pretest and posttest questionnaire and yielded a Cronbach’s alpha of .912. Paired T-test was used to analyze the gathered data. Results: The results showed that after the administration of PRIDE therapy, there was an increase on the level of self-esteem. The experimental group had a value of 3.590, which was significant and meant that the level of self-esteem is significantly increased. On the other hand, the control group, had a value of -2.207 which was also significant, therefore, the level of self esteem significantly decreased. Conclusion: the PRIDE Therapy is effective in increasing the level of self-esteem among physically challenged adolescent. Recommendations: The researchers recommend the use of PRIDE Therapy as an intervention in handling physically challenged patients, especially adolescents, in order to enhance their self-esteem. Also, the researchers recommend that nursing students be informed on the efficacy of PRIDE Therapy in enhancing the self-esteem of physically challenged patients. Furthermore, the inclusion of a psychologist during the implementation of PRIDE Therapy, specifically art therapy, to be able to have a more focused interpretation of the drawings and really be able to see the projection of their self-esteem is also recommended.

Keywords: PRIDE therapy, physically challenged adolescents, self-esteem, art therapy

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216 A New Multi-Target, Multi-Agent Search and Rescue Path Planning Approach

Authors: Jean Berger, Nassirou Lo, Martin Noel

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Perfectly suited for natural or man-made emergency and disaster management situations such as flood, earthquakes, tornadoes, or tsunami, multi-target search path planning for a team of rescue agents is known to be computationally hard, and most techniques developed so far come short to successfully estimate optimality gap. A novel mixed-integer linear programming (MIP) formulation is proposed to optimally solve the multi-target multi-agent discrete search and rescue (SAR) path planning problem. Aimed at maximizing cumulative probability of successful target detection, it captures anticipated feedback information associated with possible observation outcomes resulting from projected path execution, while modeling agent discrete actions over all possible moving directions. Problem modeling further takes advantage of network representation to encompass decision variables, expedite compact constraint specification, and lead to substantial problem-solving speed-up. The proposed MIP approach uses CPLEX optimization machinery, efficiently computing near-optimal solutions for practical size problems, while giving a robust upper bound obtained from Lagrangean integrality constraint relaxation. Should eventually a target be positively detected during plan execution, a new problem instance would simply be reformulated from the current state, and then solved over the next decision cycle. A computational experiment shows the feasibility and the value of the proposed approach.

Keywords: search path planning, search and rescue, multi-agent, mixed-integer linear programming, optimization

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215 Improving Vocabulary and Listening Comprehension via Watching French Films without Subtitles: Positive Results

Authors: Yelena Mazour-Matusevich, Jean-Robert Ancheta

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This study is based on more than fifteen years of experience of teaching a foreign language, in my case French, to the English-speaking students. It represents a qualitative research on foreign language learners’ reaction and their gains in terms of vocabulary and listening comprehension through repeatedly viewing foreign feature films with the original sountrack but without English subtitles. The initial idea emerged upon realization that the first challenge faced by my students when they find themselves in a francophone environment has been their lack of listening comprehension. Their inability to understand colloquial speech affects not only their academic performance, but their psychological health as well. To remedy this problem, I have designed and applied for many years my own teaching method based on one particular French film, exceptionally suited, for the reasons described in detail in the paper, for the intermediate-advanced level foreign language learners. This project, conducted together with my undergraduate assistant and mentoree J-R Ancheta, aims at showing how the paralinguistic features, such as characters’ facial expressions, settings, music, historical background, images provided before the actual viewing, etc., offer crucial support and enhance students’ listening comprehension. The study, based on students’ interviews, also offers special pedagogical techniques, such as ‘anticipatory’ vocabulary lists and exercises, drills, quizzes and composition topics that have proven to boost students’ performance. For this study, only the listening proficiency and vocabulary gains of the interviewed participants were assessed.

Keywords: comprehension, film, listening, subtitles, vocabulary

Procedia PDF Downloads 594
214 Obesity, Leptin Levels and Leptin Receptor Gene Polymorphisms in Afro-Caribbean Subjects

Authors: Lydia Foucan, Christine Rambhojan, Rachel Billy, Christophe Armand, Carl-Thony Michel, Jean-Marc Lacorte, Laurent Larifla

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Leptin, an adipocyte-derived hormone, modulates insulin secretion and action via the leptin receptor (LEPR) that is expressed in pancreatic beta cells, adipose tissue, and muscle. Several polymorphisms have been described in the human LEPR gene including p.K109R (rs1137100), p.Q223R (rs1137101) and p.K656N (rs1805094) polymorphisms. The role of these polymorphisms is not yet studied in Guadeloupian population. Our aim was to explore the association of LEPR polymorphisms (K109R, Q223R and K656N) with leptin levels and obesity in non-diabetic Afro-Caribbean subjects. Genotypic analysis of the three polymorphisms was performed in 425 subjects using TaqMan and KASPar Assays. Serum leptin was measured with ELISA kits Biovendor® (RD191001100). Logistic regressions were used for assessment of statistical associations. Mean age was 47.6 ± 12.7 years. Among the participants, 238 (56 %) were women, 124 (30%) were obese and 155 (36.5%) had abdominal obesity. Carriers of LEPR K656N rs1805094 rare allele had significant higher frequencies of obesity (P = 0.007), abdominal obesity (P = 0.004) and metabolic syndrome (P = 0.021) but mean leptin level was not significantly different between both groups (P = 0.075). Odds ratios, adjusted for age and sex associated with presence of rs1805094 rare allele were 1.8 (1.1-2.9), P = 0.012 for obesity, 2.0 (1.2-3.3), P = 0.008 for abdominal obesity and 1.8 (1.1-3.0), P = 0.031 for MetS. No significant association was found with K109R, Q223R. These findings suggest that the K656N polymorphism (but not the K109R or Q223R polymorphism) of LEPR is associated with obesity, abdominal obesity and metabolic syndrome in this Afro-Caribbean non-diabetic population.

Keywords: Afro-Caribbean, leptin levels, leptin receptor gene polymorphisms, obesity

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213 Liquid Chromatography Microfluidics for Detection and Quantification of Urine Albumin Using Linear Regression Method

Authors: Patricia B. Cruz, Catrina Jean G. Valenzuela, Analyn N. Yumang

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Nearly a hundred per million of the Filipino population is diagnosed with Chronic Kidney Disease (CKD). The early stage of CKD has no symptoms and can only be discovered once the patient undergoes urinalysis. Over the years, different methods were discovered and used for the quantification of the urinary albumin such as the immunochemical assays where most of these methods require large machinery that has a high cost in maintenance and resources, and a dipstick test which is yet to be proven and is still debated as a reliable method in detecting early stages of microalbuminuria. This research study involves the use of the liquid chromatography concept in microfluidic instruments with biosensor as a means of separation and detection respectively, and linear regression to quantify human urinary albumin. The researchers’ main objective was to create a miniature system that quantifies and detect patients’ urinary albumin while reducing the amount of volume used per five test samples. For this study, 30 urine samples of unknown albumin concentrations were tested using VITROS Analyzer and the microfluidic system for comparison. Based on the data shared by both methods, the actual vs. predicted regression were able to create a positive linear relationship with an R2 of 0.9995 and a linear equation of y = 1.09x + 0.07, indicating that the predicted values and actual values are approximately equal. Furthermore, the microfluidic instrument uses 75% less in total volume – sample and reagents combined, compared to the VITROS Analyzer per five test samples.

Keywords: Chronic Kidney Disease, Linear Regression, Microfluidics, Urinary Albumin

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212 Parameters Identification and Sensitivity Study for Abrasive WaterJet Milling Model

Authors: Didier Auroux, Vladimir Groza

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This work is part of STEEP Marie-Curie ITN project, and it focuses on the identification of unknown parameters of the proposed generic Abrasive WaterJet Milling (AWJM) PDE model, that appears as an ill-posed inverse problem. The necessity of studying this problem comes from the industrial milling applications where the possibility to predict and model the final surface with high accuracy is one of the primary tasks in the absence of any knowledge of the model parameters that should be used. In this framework, we propose the identification of model parameters by minimizing a cost function, measuring the difference between experimental and numerical solutions. The adjoint approach based on corresponding Lagrangian gives the opportunity to find out the unknowns of the AWJM model and their optimal values that could be used to reproduce the required trench profile. Due to the complexity of the nonlinear problem and a large number of model parameters, we use an automatic differentiation software tool (TAPENADE) for the adjoint computations. By adding noise to the artificial data, we show that in fact the parameter identification problem is highly unstable and strictly depends on input measurements. Regularization terms could be effectively used to deal with the presence of data noise and to improve the identification correctness. Based on this approach we present results in 2D and 3D of the identification of the model parameters and of the surface prediction both with self-generated data and measurements obtained from the real production. Considering different types of model and measurement errors allows us to obtain acceptable results for manufacturing and to expect the proper identification of unknowns. This approach also gives us the ability to distribute the research on more complex cases and consider different types of model and measurement errors as well as 3D time-dependent model with variations of the jet feed speed.

Keywords: Abrasive Waterjet Milling, inverse problem, model parameters identification, regularization

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211 Inversion of the Spectral Analysis of Surface Waves Dispersion Curves through the Particle Swarm Optimization Algorithm

Authors: A. Cerrato Casado, C. Guigou, P. Jean

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In this investigation, the particle swarm optimization (PSO) algorithm is used to perform the inversion of the dispersion curves in the spectral analysis of surface waves (SASW) method. This inverse problem usually presents complicated solution spaces with many local minima that make difficult the convergence to the correct solution. PSO is a metaheuristic method that was originally designed to simulate social behavior but has demonstrated powerful capabilities to solve inverse problems with complex space solution and a high number of variables. The dispersion curve of the synthetic soils is constructed by the vertical flexibility coefficient method, which is especially convenient for soils where the stiffness does not increase gradually with depth. The reason is that these types of soil profiles are not normally dispersive since the dominant mode of Rayleigh waves is usually not coincident with the fundamental mode. Multiple synthetic soil profiles have been tested to show the characteristics of the convergence process and assess the accuracy of the final soil profile. In addition, the inversion procedure is applied to multiple real soils and the final profile compared with the available information. The combination of the vertical flexibility coefficient method to obtain the dispersion curve and the PSO algorithm to carry out the inversion process proves to be a robust procedure that is able to provide good solutions for complex soil profiles even with scarce prior information.

Keywords: dispersion, inverse problem, particle swarm optimization, SASW, soil profile

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210 Bond Strength of Different Strengthening Systems: Concrete Elements under Freeze–Thaw Cycles and Salt Water Immersion Exposure

Authors: Firas Al-Mahmoud, Jean-Michel Mechling, Mohamed Shaban

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The long-term durability of fibre reinforced polymer (FRP) composites is often stated as being the main reason for the use of these materials. Indeed, structures externally or Near Surface Mounted (NSM) reinforced with Carbon Fibre Reinforcement Polymer CFRP are often in contact with temperature cycles and salt water immersion and other environmental conditions that reduce the expected durability of the system. Bond degradation is a frequent cause of premature failure of structural elements and environmental conditions are known to relate to such failures. The purpose of this study is to investigate the effect of environmental exposure on the bond for different CFRP strengthening systems. Bending tests were conducted to evaluate the bond with and without environmental exposure. The specimens were strengthened with CFRP sheets, CFRP plates and NSM CFRP rods embedded in two filling materials: epoxy resin and mortar. Then, they were exposed to up to 300 freeze–thaw cycles. One freeze–thaw cycle consisted of four stages according to ASTM or immersed in 3.5% salted tap water. A total of thirty-six specimens were prepared for this purpose. Results showed a decrease in ultimate bond strength for specimens strengthened by CFRP sheets that were immersed in salt water for 120 days, while a reduction was shown for CFRP sheet and plate bonded specimens that were subjected to 300 freeze–thaw cycles. Exposing NSM CFRP rod strengthened specimens, embedded in resin or mortar, to freeze–thaw cycles or to immersion in salt water does not affect the bond strength.

Keywords: durability, strengthening, FRP, bond, freeze–thaw

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209 The Healing Theatre: Beyond Alienation and Fixation Discourse of Three Theatrical Personalities in Bode Ojoniyi’s Dramaturgy

Authors: Oluwafemi Akinlawon Atoyebi

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This paper examines alienation and fixation as critical issues of/around mental health -crisis, sickness, and healing- through ‘Bode Ojoniyi’s dramaturgy. Two of his dramatic memoirs, arguably written to address such a life-threatening crisis between him and his employer, where he externalizes perhaps his psychological crisis, are critically analysed. This is done through a reading of the three theatrical phenomena of the actor, the character, and the audience against how he plays around the concepts of alienation and fixation within the totality of his dramaturgy beyond what could be seen as a mere academic exercise. The paper situates his apt understanding of their representations as a reflective force of a consciousness that defies psychosomatic existential conflicts. It does so by adopting a qualitative method of analysis through a critical reading of the two dramatic memoirs. It also carries out a survey on the audience that experienced the performances of the memoirs and an interview with Ojoniyi. Using Jean-Paul Sartre’s Theory of Existential Consciousness, the study discovers that there is a way the three phenomena of the actor, the character, and the audience do find expression in Ojoniyi as an existential omniscient playwright-actor-character-audience who is able to transcend the parochialism of an alienated and a fixated self; that beyond the limiting artistic purview, the theatre as a stage is a phenomenon that is capable of capturing the totality of the experiences of a man in his world and that, often time, the depressed are victims of the myopic syndrome as they probably could not see or reflect on/about their realities beyond the self and the play of a casual order. The study concludes that the therapeutic effect of Ojoniyi’s dramatic memoirs, in their reading or performance, is needed by all and should be explored in proffering cures for psychosomatic patients, for it promises to be essentially useful beyond its confine –the Arts.

Keywords: alienation, fixation, the healing theatre, theatrical personalities

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208 The Use of Respiratory Index of Severity in Children (RISC) for Predicting Clinical Outcomes for 3 Months-59 Months Old Patients Hospitalized with Community-Acquired Pneumonia in Visayas Community Medical Center, Cebu City from January 2013 - June 2

Authors: Karl Owen L. Suan, Juliet Marie S. Lambayan, Floramay P. Salo-Curato

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Objective: To predict the outcome among patients admitted with community-acquired pneumonia (ages 3 months to 59 months old) admitted in Visayas Community Medical Center using the Respiratory Index of Severity in Children (RISC). Design: A cross-sectional study design was used. Setting: The study was done in Visayas Community Medical Center, which is a private tertiary level in Cebu City from January-June 2013. Patients/Participants: A total of 72 patients were initially enrolled in the study. However, 1 patient transferred to another institution, thus 71 patients were included in this study. Within 24 hours from admission, patients were assigned a RISC score. Statistical Analysis: Cohen’s kappa coefficient was used for inter-rater agreement for categorical data. This study used frequency and percentage distribution for qualitative data. Mean, standard deviation and range were used for quantitative data. To determine the relationship of each RISC score parameter and the total RISC score with the outcome, a Mann Whitney U Test and 2x2 Fischer Exact test for testing associations were used. A p value less of than 0.05 alpha was considered significant. Results: There was a statistical significance between RISC score and clinical outcome. RISC score of greater than 4 was correlated with intubation and/or mortality. Conclusion: The RISC scoring system is a simple combination of clinical parameters and a reliable tool that will help stratify patients aged 3 months to 59 months in predicting clinical outcome.

Keywords: RISC, clinical outcome, community-acquired pneumonia, patients

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207 Numerical Simulation of Two-Phase Flows Using a Pressure-Based Solver

Authors: Lei Zhang, Jean-Michel Ghidaglia, Anela Kumbaro

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This work focuses on numerical simulation of two-phase flows based on the bi-fluid six-equation model widely used in many industrial areas, such as nuclear power plant safety analysis. A pressure-based numerical method is adopted in our studies due to the fact that in two-phase flows, it is common to have a large range of Mach numbers because of the mixture of liquid and gas, and density-based solvers experience stiffness problems as well as a loss of accuracy when approaching the low Mach number limit. This work extends the semi-implicit pressure solver in the nuclear component CUPID code, where the governing equations are solved on unstructured grids with co-located variables to accommodate complicated geometries. A conservative version of the solver is developed in order to capture exactly the shock in one-phase flows, and is extended to two-phase situations. An inter-facial pressure term is added to the bi-fluid model to make the system hyperbolic and to establish a well-posed mathematical problem that will allow us to obtain convergent solutions with refined meshes. The ability of the numerical method to treat phase appearance and disappearance as well as the behavior of the scheme at low Mach numbers will be demonstrated through several numerical results. Finally, inter-facial mass and heat transfer models are included to deal with situations when mass and energy transfer between phases is important, and associated industrial numerical benchmarks with tabulated EOS (equations of state) for fluids are performed.

Keywords: two-phase flows, numerical simulation, bi-fluid model, unstructured grids, phase appearance and disappearance

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206 Selectivity Mechanism of Cobalt Precipitation by an Imidazole Linker From an Old Battery Solution

Authors: Anna-Caroline Lavergne-Bril, Jean-François Colin, David Peralta, Pascale Maldivi

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Cobalt is a critical material, widely used in Li-ion batteries. Due to the planned electrification of European vehicles, cobalt needs are expending – and resources are limited. To meet the needs in cobalt to come, it is necessary to develop new efficient ways to recycle cobalt. One of the biggest sources comes from old electrical vehicles batteries (batteries sold in 2019: 500 000 tons of waste to be). A closed loop process of cobalt recycling has been developed and this presentation aims to present the selectivity mechanism of cobalt over manganese and nickel in solution. Cobalt precipitation as a ZIF material (Zeolitic Imidazolate framework) from a starting solution composed of equimolar nickel, manganese and cobalt is studied. A 2-MeIm (2-methylimidazole) linker is introduced in a multimetallic Ni, Mn, Co solution and the resulting ZIF-67 is 100% pure Co among its metallic centers. Selectivity of Co over Ni is experimentally studied and DFT modelisation calculation are conducted to understand the geometry of ligand-metal-solvent complexes in solution. Selectivity of Co over Mn is experimentally studied, and DFT modelisation calcucation are conducted to understand the link between pKa of the ligand and precipitration of Mn impurities within the final material. Those calculation open the way to other ligand being used in the same process, with more efficiency. Experimental material are synthetized from bimetallic (Ni²⁺/Co²⁺, Mn²⁺/Co²⁺, Mn²⁺/Ni²⁺) solutions. Their crystallographic structure is analysed by XRD diffraction (Brüker AXS D8 diffractometer, Cu anticathode). Morphology is studied by scanning electron microscopy, using a LEO 1530 FE-SEM microscope. The chemical analysis is performed by using ICP-OES (Agilent Technologies 700 series ICP-OES). Modelisation calculation are DFT calculation (density functional theory), using B3LYP, conducted with Orca 4.2.

Keywords: MOFs, ZIFs, recycling, closed-loop, cobalt, li-ion batteries

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205 Stock Market Integration of Emerging Markets around the Global Financial Crisis: Trends and Explanatory Factors

Authors: Najlae Bendou, Jean-Jacques Lilti, Khalid Elbadraoui

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In this paper, we examine stock market integration of emerging markets around the global financial turmoil of 2007-2008. Following Pukthuanthong and Roll (2009), we measure the integration of 46 emerging countries using the adjusted R-square from the regression of each country's daily index returns on global factors extracted from the covariance matrix computed using dollar-denominated daily index returns of 17 developed countries. Our sample surrounds the global financial crisis and ranges between 2000 and 2018. We analyze results using four cohorts of emerging countries: East Asia & Pacific and South Asia, Europe & Central Asia, Latin America & Caribbean, Middle East & Africa. We find that the level of integration of emerging countries increases at the commencement of the crisis and during the booming phase of the business cycles. It reaches a maximum point in the middle of the crisis and then tends to revert to its pre-crisis level. This pattern tends to be common among the four geographic zones investigated in this study. Finally, we investigate the determinants of stock market integration of emerging countries in our sample using panel regressions. Our results suggest that the degree of stock market integration of these countries should be put into perspective by some macro-economic factors, such as the size of the equity market, school enrollment rate, international liquidity level, stocks traded volume, tax revenue level, imports and exports volumes.

Keywords: correlations, determinants of integration, diversification, emerging markets, financial crisis, integration, markets co-movement, panel regressions, r-square, stock markets

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204 Variation In Gastrocnemius and Hamstring Muscle Activity During Peak Knee Flexor Torque After Anterior Cruciate Ligament Reconstruction with Hamstring Graft

Authors: Luna Sequier, Florian Forelli, Maude Traulle, Amaury Vandebrouck, Pascal Duffiet, Louis Ratte, Jean Mazeas

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The study's objective is to compare the muscular activity of the flexor knee muscle in patients who underwent an anterior cruciate ligament reconstruction with hamstring autograft and the individuals who have not undergone surgery. Methods: The participants were divided into two groups: a healthy group and an experimental group who had undergone an anterior cruciate ligament reconstruction with a hamstring graft. All participants had to perform a knee flexion strength test on an isokinetic dynamometer. The medial Gastrocnemius, lateral Gastrocnemius, Biceps femoris, and medial Hamstring muscle activity were measured during this test. Each group’s mean muscle activity was tested with statistical analysis, and a muscle activity ratio of gastrocnemius and hamstring muscles was calculated Results: The results showed a significant difference in activity of the medial gastrocnemius (p = 0,004901), the biceps femoris (p = 5,394.10-6), and the semitendinosus muscles (p = 1,822.10-6), with a higher Biceps femoris and Semitendinosus activity for the experimental group. It is however noticeable that inter-subject differences were important. Conclusion: This study has shown a difference in the gastrocnemius and hamstring muscle activity between patients who underwent an anterior cruciate ligament reconstruction surgery and healthy participants. With further results, this could show a modification of muscle activity patterns after surgery which could lead to compensatory behaviors at a return to sport and eventually explain a higher injury risk for our patients.

Keywords: anterior cruciate ligament, electromyography, muscle activity, physiotherapy

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203 Improving Access to Training for Parents of Children with Autism Spectrum Disorders through Telepractice: Parental Perception

Authors: Myriam Rousseau, Marie-Hélène Poulin, Suzie McKinnon, Jacinthe Bourassa

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Context: There is a growing demand for effective training programs for parents of children with autism spectrum disorders. While traditional in-person training is effective, it can be difficult for some parents to participate due to distance, time, and cost. Telepractice, a form of distance education, could be a viable alternative to address these challenges. Research objective: The objective of this study is to explore the experiences of parents of children with autism who participated in a training program offered by telepractice in order to document: 1) the experience of parents who participated in a program telepractice training program for autistic children, 2) parental satisfaction with the telepractice modality, and 3) potential benefits of using telepractice to deliver training programs to parents of autistic children. Method: This study followed a qualitative research design, and Braun and Clarke's six-step procedure was used for the thematic analysis of the comments provided by parents. Data were collected through individual interviews with parents who participated in the project. The analysis focused on identifying patterns and themes in the comments in order to better understand parents' experiences with the telepractice modality. Results: The study revealed that parents were generally satisfied with the telepractice modality, as it was easy to use and enabled a better balance between work and family. This modality also enabled parents to share and receive mutual support. Despite the positive results, it is still relevant to offer training in different modalities to meet the different needs of parents. Conclusion: The study shows that parents of children with autism are generally satisfied with telepractice as a training modality. The results suggest that telepractice can be an effective alternative to traditional face-to-face training. The study highlights the importance of taking parents' needs and preferences into account when designing and implementing training programs.

Keywords: parents, children, training, telepractice

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202 Impact of Soot on NH3-SCR, NH3 Oxidation and NH3 TPD over Cu/SSZ-13 Zeolite

Authors: Lidija Trandafilovic, Kirsten Leistner, Marie Stenfeldt, Louise Olsson

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Ammonia Selective Catalytic Reduction (NH3 SCR), is one of the most efficient post combustion abatement technologies for removing NOx from diesel engines. In order to remove soot, diesel particulate filters (DPF) are used. Recently, SCR coated filters have been introduced, which captures soot and simultaneously is active for ammonia SCR. There are large advantages with using SCR coated filters, such as decreased volume and also better light off characteristics, since both the SCR function as well as filter function is close to the engine. The objective of this work was to examine the effect of soot, produced using an engine bench, on Cu/SSZ-13 catalysts. The impact of soot on Cu/SSZ-13 in standard SCR, NH3 oxidation, NH3 temperature programmed desorption (TPD), as well as soot oxidation (with and without water) was examined using flow reactor measurements. In all experiments, prior to the soot loading, the fresh activity of Cu/SSZ-13 was recorded with stepwise increasing the temperature from 100°C till 600°C. Thereafter, the sample was loaded with soot and the experiment was repeated in the temperature range from 100°C till 700°C. The amount of CO and CO2 produced in each experiment is used to calculate the soot oxidized at each steady state temperature. The soot oxidized during the heating to next temperature step is included, e.g. the CO+CO2 produced when increasing the temperature to 600°C is added to the 600°C step. The influence of the two factors seem to be of the most importance to soot oxidation: ammonia and water. The influence of water on soot oxidation shift the maximum of CO2 and CO production towards lower temperatures, thus water increases the soot oxidation. Moreover, when adding ammonia to the system it is clear that the soot oxidation is lowered in the presence of ammonia, resulting in larger integrated COx at 500°C for O2+H2O, while opposite results at 600 °C was received where more was oxidised for O2+H2O+NH3 case. To conclude the presence of ammonia reduces the soot oxidation, which is in line with the ammonia TPD results where we found ammonia storage on the soot. Interestingly, during ammonia SCR conditions the activity for soot oxidation is regained at 500°C. At this high temperature the SCR zone is very short, thus the majority of the catalyst is not exposed to ammonia and therefore the inhibition effect of ammonia is not observed.

Keywords: NH3-SCR, Cu/SSZ-13, soot, zeolite

Procedia PDF Downloads 205
201 Clean Sky 2 Project LiBAT: Light Battery Pack for High Power Applications in Aviation – Simulation Methods in Early Stage Design

Authors: Jan Dahlhaus, Alejandro Cardenas Miranda, Frederik Scholer, Maximilian Leonhardt, Matthias Moullion, Frank Beutenmuller, Julia Eckhardt, Josef Wasner, Frank Nittel, Sebastian Stoll, Devin Atukalp, Daniel Folgmann, Tobias Mayer, Obrad Dordevic, Paul Riley, Jean-Marc Le Peuvedic

Abstract:

Electrical and hybrid aerospace technologies pose very challenging demands on the battery pack – especially with respect to weight and power. In the Clean Sky 2 research project LiBAT (funded by the EU), the consortium is currently building an ambitious prototype with state-of-the art cells that shows the potential of an intelligent pack design with a high level of integration, especially with respect to thermal management and power electronics. For the latter, innovative multi-level-inverter technology is used to realize the required power converting functions with reduced equipment. In this talk the key approaches and methods of the LiBat project will be presented and central results shown. Special focus will be set on the simulative methods used to support the early design and development stages from an overall system perspective. The applied methods can efficiently handle multiple domains and deal with different time and length scales, thus allowing the analysis and optimization of overall- or sub-system behavior. It will be shown how these simulations provide valuable information and insights for the efficient evaluation of concepts. As a result, the construction and iteration of hardware prototypes has been reduced and development cycles shortened.

Keywords: electric aircraft, battery, Li-ion, multi-level-inverter, Novec

Procedia PDF Downloads 133
200 Integration of an Augmented Reality System for the Visualization of the HRMAS NMR Analysis of Brain Biopsy Specimens Using the Brainlab Cranial Navigation System

Authors: Abdelkrim Belhaoua, Jean-Pierre Radoux, Mariana Kuras, Vincent Récamier, Martial Piotto, Karim Elbayed, François Proust, Izzie Namer

Abstract:

This paper proposes an augmented reality system dedicated to neurosurgery in order to assist the surgeon during an operation. This work is part of the ExtempoRMN project (Funded by Bpifrance) which aims at analyzing during a surgical operation the metabolic content of tumoral brain biopsy specimens by HRMAS NMR. Patients affected with a brain tumor (gliomas) frequently need to undergo an operation in order to remove the tumoral mass. During the operation, the neurosurgeon removes biopsy specimens using image-guided surgery. The biopsy specimens removed are then sent for HRMAS NMR analysis in order to obtain a better diagnosis and prognosis. Image-guided refers to the use of MRI images and a computer to precisely locate and target a lesion (abnormal tissue) within the brain. This is performed using preoperative MRI images and the BrainLab neuro-navigation system. With the patient MRI images loaded on the Brainlab Cranial neuro-navigation system in the operating theater, surgeons can better identify their approach before making an incision. The Brainlab neuro-navigation tool tracks in real time the position of the instruments and displays their position on the patient MRI data. The results of the biopsy analysis by 1H HRMAS NMR are then sent back to the operating theater and superimposed on the 3D localization system directly on the MRI images. The method we have developed to communicate between the HRMAS NMR analysis software and Brainlab makes use of a combination of C++, VTK and the Insight Toolkit using OpenIGTLink protocol.

Keywords: neuro-navigation, augmented reality, biopsy, BrainLab, HR-MAS NMR

Procedia PDF Downloads 341
199 Effect of Exercise Training on Body Composition and Metabolic Profile in Older Adults during Cancer Treatment

Authors: Adeline Fontvieille, Hugo Parent-Roberge, Marie-France Langlois, Tamas Fulop, Michel Pavic, Eleonor Riesco

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Introduction: Total lean body mass is reduced during cancer treatment. This loss is called cancer cachexia and is accompanied by a progressive loss of fat mass. In older adults, these body composition changes can have a larger impact on metabolic health, physical autonomy, and cancer survival. Although currently untreatable, exercise training could reduce these effects. Hence, the objective of this pilot study is to investigate if 12 weeks of exercise training during cancer treatment can mitigate the loss of muscle mass and fat mass in older adults. Methods: A total of 40 older adults (65-80 years) with an ongoing treatment for a curable cancer are currently recruited and randomised in two groups: 1) Combined training (EX, n=20) and 2) Control group (CON, n=20). All variables are measured before and after 12 weeks of intervention: Anthropometry (weight, height, body mass index), body composition (total fat mass, visceral adipose tissue, total and appendicular muscle mass; DXA), metabolic profile (HDL-C and LDL-C, triglycerides, glucose and insulin levels). Results: Preliminary analyses revealed no impact of exercise training on appendicular muscle mass (p=0,31) and fat mass (p=0,31). Furthermore, total body weight, waist circumference, HDL-cholesterol, LDL-cholesterol, glucose and insulin levels remained unchanged (all p ≥ 0.79) after 12 weeks of training. However, statistical analyses revealed that triglyceride levels slightly increased (p=0.03), irrespective of the group. Conclusion: Preliminary analyses did not reveal any impact of aerobic and resistance exercise training on body composition in oncogeriatric patients. Furthermore, exercise training seems not efficient to prevent the cancer treatment-related triglyceride levels increase.

Keywords: muscle mass, fat mass, metabolic profile, combined training, aging, cancer

Procedia PDF Downloads 331
198 Spinochromes: Kairomones Involved in the Symbiosis between the Shrimp Tuleariocaris holthuisi and Echinometra mathaei

Authors: Lola Brasseur, Guillaume Caulier, Marie Demeyer, Pascal Gerbaux, Igor Eeckhaut

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Seawater being an ideal dispersing agent, chemical communication stays predominant in marine ecosystems. However, if many molecules acting in chemical heterospecific communication have already been well described in terrestrial ecosystems, only three of these molecules were identified in marine ecosystems. Echinoderms and their symbiotic organisms constitute very good models to study heterospecific chemical communication because each class synthesizes a specific type of molecules and symbioses with echinoderms as hosts are very usual. In this study, the chemical communication that allows the commensal shrimps Tuleariocaris holthuisi Hipeau-Jacquotte, 1965 to live with their host Echinometra mathaei (Blainville, 1825) was investigated. The chemoreception of the shrimp was characterized using olfactometers and it was demonstrated that hosts and synthetic hydroxynaphthoquinones are attractive to the symbiotic shrimps. Hydroxynaphthoquinonic pigments also known as spinochromes are by the way synthesized by sea urchin and involved in all probability in a lot of mechanisms. To our knowledge, this study is the first highlighting the ecological function of naphthoquinones as kairomones. Chemical extractions were also performed on sea urchins in order to analyze and identify their specific hydroxynaphthoquinones using HPLC-ESI-MS. Accurate mass identification and elemental composition have been performed on various organs (gonads, coelomic liquid, digestive system and test) in different morphotypes of Echinometra mathaei for a better understanding of the molecular diversity of these semiochemicals. Moreover, some experiments were performed to investigate the dependence of T. holthuisi for their host. First, the analyses showed that the molecules involved in shrimp pigmentation are the same that the ones involved in E. mathaei, suggesting a potential feeding on the host. Secondly, a substantial shrimp depigmentation and an increase of the mortality rate were demonstrated after the symbionts-host separation which could mean a potential implication of spinochromes in the shrimp metabolism.

Keywords: crustacean, sea urchin, spinochrome, symbiosis

Procedia PDF Downloads 162
197 Factors Affecting Online Health Seeking Behaviors in Middle-Income Class Filipino Adults

Authors: Reinzo Vittorio B. Cardenas, Heather Venice L. Abogado, Andrea Therese V. Afable, Rhea D. Avillanoza, Marie Abegail P. Ayagan, Catherine D. Bantayan

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As the Internet provides fast and reliable health-related information, the tendency to self-diagnose increases to further understand medical jargon in a diagnosis with a physician and decreases costly consultation fees. The study aimed to explore and understand the factors affecting online health-seeking behaviors in middle-income class adults in Metro Manila. The study was conducted from March to April of 2021 with a sample size of 200 individuals aged 20 to 49 years old. The study was delivered via an online survey that used a questionnaire adapted from the research of Lee et al. (2015). Specifically, the survey consisted of three sections: assessing web-based health-seeking behaviors, consultation with health professionals, and participants' hesitancy to consult with physicians, which used a mix of a 5-point Likert-type scale with multiple responses and multiple-choice options. The results showed that the age and educational attainment of the respondents had a negative effect while presenting a positive effect of socio-economic status on health-seeking behavior. Lastly, there was a significant effect of participant’s hesitancy for professional consultation on their health-seeking behavior. The results gleaned from the study indicated that various individual and socio-economic factors might significantly affect one’s health-seeking behaviors. Although hesitancy had a significant effect on the spectrum of health-seeking behaviors, this does not imply that certain factors are specifically related to an individual’s tendency to seek health information. This information instead becomes essential in understanding the patient-physician relationship and giving patients a more holistic treatment.

Keywords: health-seeking behavior, health information, Internet, physician consultation

Procedia PDF Downloads 193
196 Tokyo Skyscrapers: Technologically Advanced Structures in Seismic Areas

Authors: J. Szolomicki, H. Golasz-Szolomicka

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The architectural and structural analysis of selected high-rise buildings in Tokyo is presented in this paper. The capital of Japan is the most densely populated city in the world and moreover is located in one of the most active seismic zones. The combination of these factors has resulted in the creation of sophisticated designs and innovative engineering solutions, especially in the field of design and construction of high-rise buildings. The foreign architectural studios (as, for Jean Nouvel, Kohn Pedesen Associates, Skidmore, Owings & Merill) which specialize in the designing of skyscrapers, played a major role in the development of technological ideas and architectural forms for such extraordinary engineering structures. Among the projects completed by them, there are examples of high-rise buildings that set precedents for future development. An essential aspect which influences the design of high-rise buildings is the necessity to take into consideration their dynamic reaction to earthquakes and counteracting wind vortices. The need to control motions of these buildings, induced by the force coming from earthquakes and wind, led to the development of various methods and devices for dissipating energy which occur during such phenomena. Currently, Japan is a global leader in seismic technologies which safeguard seismic influence on high-rise structures. Due to these achievements the most modern skyscrapers in Tokyo are able to withstand earthquakes with a magnitude of over seven degrees at the Richter scale. Damping devices applied are of a passive, which do not require additional power supply or active one which suppresses the reaction with the input of extra energy. In recent years also hybrid dampers were used, with an additional active element to improve the efficiency of passive damping.

Keywords: core structures, damping system, high-rise building, seismic zone

Procedia PDF Downloads 147
195 Antibacterial Activity and Kinetic Parameters of the Essential Oils of Drypetes Gossweileri S.Moore, Ocimun Gratissimum L. and Cymbopogon Citratus DC Stapf on 5 Multidrug-Resistant Strains of Shigella

Authors: Elsa Makue Nguuffo, Esther Del Florence Moni Ndedi, Jacky Njiki Bikoï, Jean Paul Assam Assam, Maximilienne Ascension Nyegue

Abstract:

Aims: The present study aims to evaluate the kinetic parameters of essential oils (EOs) and combinations fromDrypetes gossweileri Stem Bark, Ocimum gratissimum leaves, Cymbopogon citratusleaves after evaluation of their antibacterial activityonmultidrug-resistant strains ofShigella. Material and Methods:fiveclinical strains of Shigellaisolated from patients with diarrhoeaincluding Shigella flexneri, and 4 otherstrains of Shigella sppwere selected. Their antibiotic profile was established using agar test diffusion with seven antibiotics belonging to seven classes.EOs were extracted from each plant using hydrodistillation process. The activity of Ciprofloxacin®, OEs, and their combination formulatedinthe followingratios(w/w/w): C1: 1/1/1; C2: 2/1/1; C3: 1/2/1, C4:1/1/2 was evaluated microdilution assay. The various interactions of OEs in the different combinations were determined then the OE and the most active combination were retained to determine their kinetic parameters on S. flexneri. Results: Antibiotic susceptibility tests revealed that most Shigella isolates (n = 4) were resistant to six antibiotics tested. Ciprofloxacin (40%), Nalidixic acid (60%), Tetracycline (80%), Amoxicillin (100%), Cefotaxime (80%), Erythromycin (100%), and Cotrimoxazole (80%) were the profiles found in the different strains of Shigella. About the antibacterial activity of OEs, Drypetes gossweileriOE and C2 combination had shown a higher Shigellicide property with a Minimal Inhibitory Concentration(MIC) respectivelyranging from 0.078 mg/mL to 0.312 mg/mL and 0.012 to 1.562 mg/mL. Combinations of OEs showed various interactions whose synergistic effects were mostly encountered. The best deactivation was obtained by the combination C2 at 16 MIC withb= 1.962. Conclusion: the susceptibility of Shigella to OEs and their combinations justifies their use in traditional medicine in the treatment of shigellosis.

Keywords: shigella, multidrug-resistant, EOs, kinetic

Procedia PDF Downloads 65
194 Beyond Baudrillard: A Critical Intersection between Semiotics and Materialism

Authors: Francesco Piluso

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Nowadays, to restore the deconstructive power of semiotics implies a critical analysis of neoliberal ideology, and, even more critically, a confrontation with materialist perspective. The theoretical path of Jean Baudrillard is crucial to understand the ambivalence of this intersection. A semiotic critique of Baudrillard’s work, through tools of both structuralism and interpretative semiotics, has the aim to give materialism a new consistent semiotic approach and vice-versa. According to Baudrillard, the commodity form is characterized by the same abstract and systemic logic of the sign-form, in which the production of the signified (use-value) is a mere ideological mean for the reproduction of the signifiers-chain (exchange-value). Nevertheless, this parallelism is broken by the author himself: if the use-value is deconstructed in its relative logic, the signified and the referent, both as discrete and positive elements, are collapsed on the same plane at the shadows of the signified forms. These divergent considerations lead Baudrillard to the same crucial point: the dismissal of the material world, replaced by the hyperreality as reproduction of a semiotic (genetic) Code. The stress on the concept of form, as an epistemological and semiotic tool to analyse the construction of values in the consumer society, has led to the Code as its ontological drift. In other words, Baudrillard seems to enclose consumer society (and reality) in this immanent and self-fetishized world of signs–an ideological perspective that mystifies the gravity of the material relationships between Northern-Western World and Third World. The notion of Encyclopaedia by Umberto Eco is the key to overturn the relationship of immanence/transcendence between the Code and the economic political of the sign, by understanding the former as an ideological plane within the encyclopedia itself. Therefore, rather than building semiotic (hyper)realities, semiotics has to deal with materialism in terms of material relationships of power which are mystified and reproduced through such ideological ontologies of signs.

Keywords: Baudrillard, Code, Eco, Encyclopaedia, epistemology vs. ontology, semiotics vs. materialism

Procedia PDF Downloads 133
193 Students’ Academic and Personal Needs: Basis for a Guidance Program

Authors: Susan Marie R. De La Cruz, Bernadette F. De La Cruz, Georgia D. Demavibas

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This study determined the top 10 perceived students’ academic needs, personal needs, personal obstacles in achieving their academic goals, are as they need assistance, and their perceived feelings in math, reading and writing. The North Carolina State College, Student Support Services needs assessment survey was used. The respondents were the randomly chosen122Graduate school students. The top 10 academic needs are as follows: need to improve memory, communication skills, study habits, time management skills, career decisions, vocabulary, math skills, test taking skills, reading comprehension, and the need to reduce math anxiety. Top 10 personal needs are as follows: difficulty meeting deadline, difficulty managing money, inadequate computer skills, afraid of failing graduate school, difficulty participating in class/group discussions, absence from school, anxiety during exams, little or no experience with internet, personal counseling needs, and unsure of university academic procedures. Students’ top 10 perceived personal obstacles were as follows: issues surrounding sickness in family, lack of time management, lack of money, feeling tired, fears to speak in class, poor study habits, problems at home, late in class, too shy, and always feeling sick and easily distracted. Students felt need assistance in areas surrounding personal budget, stress management, motivation, anxiety, depressions, leadership development and goals/decision making. It is recommended that enrichment activities be provided to respond to students’ academic and personal needs. Also, Graduate School Guidance Counselor collaborates with other licensed Guidance Counselors in other colleges to have a well-coordinated and effective delivery of services responsive to students’ needs.

Keywords: academic needs, guidance counsellors, guidance service, needs assessment survey, personal needs, student services

Procedia PDF Downloads 305
192 Estimation of Exhaust and Non-Exhaust Particulate Matter Emissions’ Share from On-Road Vehicles in Addis Ababa City

Authors: Solomon Neway Jida, Jean-Francois Hetet, Pascal Chesse

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Vehicular emission is the key source of air pollution in the urban environment. This includes both fine particles (PM2.5) and coarse particulate matters (PM10). However, particulate matter emissions from road traffic comprise emissions from exhaust tailpipe and emissions due to wear and tear of the vehicle part such as brake, tire and clutch and re-suspension of dust (non-exhaust emission). This study estimates the share of the two sources of pollutant particle emissions from on-roadside vehicles in the Addis Ababa municipality, Ethiopia. To calculate its share, two methods were applied; the exhaust-tailpipe emissions were calculated using the Europeans emission inventory Tier II method and Tier I for the non-exhaust emissions (like vehicle tire wear, brake, and road surface wear). The results show that of the total traffic-related particulate emissions in the city, 63% emitted from vehicle exhaust and the remaining 37% from non-exhaust sources. The annual roads transport exhaust emission shares around 2394 tons of particles from all vehicle categories. However, from the total yearly non-exhaust particulate matter emissions’ contribution, tire and brake wear shared around 65% and 35% emanated by road-surface wear. Furthermore, vehicle tire and brake wear were responsible for annual 584.8 tons of coarse particles (PM10) and 314.4 tons of fine particle matter (PM2.5) emissions in the city whereas surface wear emissions were responsible for around 313.7 tons of PM10 and 169.9 tons of PM2.5 pollutant emissions in the city. This suggests that non-exhaust sources might be as significant as exhaust sources and have a considerable contribution to the impact on air quality.

Keywords: Addis Ababa, automotive emission, emission estimation, particulate matters

Procedia PDF Downloads 100
191 Linear and Nonlinear Resonance of Flat Bottom Hole in an Aluminum Plate

Authors: Biaou Jean-Baptiste Kouchoro, Anissa Meziane, Philippe Micheau, Mathieu Renier, Nicolas Quaegebeur

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Numerous experimental and numerical studies have shown the interest of the local defects resonance (LDR) for the Non-Destructive Testing of metallic and composite plates. Indeed, guided ultrasonic waves such as Lamb waves, which are increasingly used for the inspection of these flat structures, enable the generation of local resonance phenomena by their interaction with a damaged area, allowing the detection of defects. When subjected to a large amplitude motion, a nonlinear behavior can predominate in the damaged area. This work presents a 2D Finite Element Model of the local resonance of a 12 mm long and 5 mm deep Flat Bottom Hole (FBH) in a 6 mm thick aluminum plate under the excitation induced by an incident A0 Lamb mode. The analysis of the transient response of the FBH enables the precise determination of its resonance frequencies and the associate modal deformations. Then, a linear parametric study varying the geometrical properties of the FBH highlights the sensitivity of the resonance frequency with respect to the plate thickness. It is demonstrated that the resonance effect disappears when the ratio of thicknesses between the FBH and the plate is below 0.1. Finally, the nonlinear behavior of the FBH is considered and studied introducing geometrical (taken into account the nonlinear component of the strain tensor) nonlinearities that occur at large vibration amplitudes. Experimental analysis allows observation of the resonance effects and nonlinear response of the FBH. The differences between these experimental results and the numerical results will be commented on. The results of this study are promising and allow to consider more realistic defects such as delamination in composite materials.

Keywords: guided waves, non-destructive testing, dynamic field testing, non-linear ultrasound/vibration

Procedia PDF Downloads 107