Search results for: chemistry class

Authors: Srinivasapriyan Vijayan

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Phenol is one of the most vital chemical in industry. Nowadays, phenol production is based upon the three-step cumene process, which involves a hazardous cumene hydroperoxide intermediate and produces nearly equimolar amounts of acetone as a coproduct. An attractive route in phenol production is the direct one-step selective hydroxylation of benzene using eco-friendly oxidants such as O2, N2O, and H2O2. In particular, the direct hydroxylation of benzene to form phenol with O2 has recently attracted extensive research attention because this process is green clean and eco-friendly. However, most of the catalytic systems involving O2 have a low rate of hydroxylation because the direct introduction of hydroxyl functionality into benzene is challenging. Almost all the developed catalytic systems require an elevated temperature and suffer from low conversion because of the notoriously low reactivity of aromatic C–H bonds. Moreover, increased reactivity of phenol relative to benzene makes the selective oxidation of benzene to phenol very difficult, especially under heating conditions. Hollow spheres, a very fascinating class of materials with good permeation and low density, highly monodisperse MOF hollow sandwich spheres have been rationally synthesized using monodisperse polystyrene (PS) nanoparticles as templates through a versatile step-by-step self-assembly strategy. So, our findings could pave the way toward highly efficient nonprecious catalysts for low-temperature oxidation reactions in heterogeneous catalysis. Because it is easy post-reaction separation, its cheap, green and recyclable.

Keywords: benzene hydroxylation, Fe-based metal organic frameworks, molecular oxygen, phenol

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Authors: H. Zouaoui, D. Abdi, B. Nessark, F. Habelhames, A. Bahloul

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Among the conjugated organic polymers, the polythiophenes constitute a particularly important class of conjugated polymers, which has been extensively studied for the relation between the geometrical structure and the optic and electronic properties, while the polythiophene is an intractable material. They are, furthermore, chemically and thermally stable materials, and are very attractive for exploitation of their physical properties. The polythiophenes are extensively studied due to the possibility of synthesizing low band gap materials by using substituted thiophenes as precursors. Low band gap polymers may convert visible light into electricity and some photoelectrochemical cells based on these materials have been prepared. Polythiophenes (PThs) are good candidates for polymer optoelectronic devices such as polymer solar cells (PSCs) polymer light-emitting diodes (PLEDs) field-effect transistors (FETs) electrochromics and biosensors. In this work, MnO2 has been synthesized by hydrothermal method and analyzed by infrared spectroscopy. The polybithiophene+MnO2 composite films were electrochemically prepared by cyclic voltammetry technic on a conductor glass substrate ITO (indium–tin-oxide). The composite films are characterized by cyclic voltammetry, impedance spectroscopy and photoelectrochemical analyses. The results confirmed the presence of manganese dioxide nanoparticles in the polymer layer. An application has been made by using these deposits as an electrode in a photoelectrochemical cell for measuring photocurrent tests. The composite films show a significant photocurrent intensity 80 μA.cm-2.

Keywords: polybithiophene, MnO2, photoelectrochemical cells, composite films

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Authors: Christine Ivy A. Nogot

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Under the colony of Spain for more than three centuries, the Philippines has a deep-rooted structure of Western ideologies and colonialism. The late 19th century, the period of Enlightenment, created a significant impact on our history when a group of middle-class Filipino men were sent to Europe to study. They were called Ilustrados, a Spanish word for erudite. They were the enlightened; the well-educated, intellectual scholars. Their writings provide intellectual grounds for the awakening of national consciousness that eventually prompted national movements and revolutions. They helped to establish a postcolonial society. In the modern era, Miguel Syjuco, a Filipino expatriate, wrote a novel and titled it Ilustrado. It is a representation of the liberal mind of the diasporic author in contemporary discourse. It provides a critical examination of the ilustrado in transition through the character of Miguel, who is also an expatriate writer. Using Syjuco’s award-winning novel as the primary text and anchored on Said’s concept of Orientalism, this paper examines how the depiction of features of the Eastern world is presented in the literary discourse. This paper looks into Said’s concept of orientalism as a hegemonic discursive structure and shows how Western superiority influences the Eastern culture in literary discourse. It explores Gramsci’s theory of cultural hegemony to explore Said’s argument that Western powers conquer the orient through culture and ideology. This paper presents how dominant ideologies and the social context redefine the ilustrado in the contemporary era.

Keywords: cultural hegemony, ilustrado, orientalism, postcolonial

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Authors: Narmeen Ali, Muhammad Arshad

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Cohesion has an exact association with family functioning and enmeshment (togetherness) on one side and disengagement (separateness) on the other. Family cohesion can apprehend as a concerned association that family members have with each other and an affirmation of association inside the family. Family cohesion, assigned as the level of congruity or sympathetic or emotional attachment that relatives have toward each other, and it was seen to be associated with relational well-being and feeling of comfort in the young generation. The cross-sectional research design was used by the researcher to answer the research questions. A stratified sampling technique was used to collect the data from the participants. The data was collected equally from the males and females of different universities and different departments of Lahore, Pakistan. A self-report questionnaire was developed of given literature and which were found to be associated with family cohesion, interpersonal difficulties and mental health problems of university students. The demographic information included age, gender, university’s name, class, family system, parent’s education, parent’s profession, number of siblings and birth order. Correlation shows the negative relation between balanced cohesion and interpersonal difficulties, while interpersonal difficulties have a highly positive relationship with mental health problems. Mental health problems also have a negative correlation with the balanced family cohesion. Gender, family system, depression and anxiety are the significant predictors of interpersonal difficulties scale in university students. And gender showed a significant difference regarding family cohesion and interpersonal difficulty scale, as women reported more interpersonal difficulties than men.

Keywords: family cohesion, interpersonal difficulties, mental health problems, university students

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Authors: Jinhee Kang, Kwangman Park, Ruhee Song, Suhee Kim, Do-Hyeon Yu, Kyoungseong Choi, Jinho Park

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Statement of the Problem: Animal blood components maintain homeostasis when animals are healthy, and changes in chemical composition of the blood and body fluids can be observed if animals have a disease. In particular, newborn calves are susceptible to disease and therefore hematologic tests and serum chemistry tests could become an important guideline to the diagnosis and the treatment of diseases. Diarrhea in newborn calves is the most damaging to cattle ranch, whether dairy or cattle fattening, and is a large part of calf atrophy and death. However, since the study on calf electrophoresis was not carried out, a survey analysis was conducted on it. Methodology and Theoretical Orientation: The calves were divided into healthy calves and disease (diarrhea) calves, and calves were classified by 1-14d, 15-28d, and more than 28d, respectively. The fecal state was classified by solid (0-value), semi-solid (1-value), loose (2-value) and watery (3-value). In the solid (0-value) and semi-solid (1-value) feces valuable pathogen was not detected, but loose (2-value) and watery (3-value) feces were detected. Findings: ALB, α-1, α-2, α-SUM, β and γ (Gamma) were examined by electrophoresis analysis of healthy calves and diarrhea calves. Test results showed that there were age differences between healthy calves and diarrheic calves. When we look at the γ-globulin at 1-14 days of age, we can see that the average calf of healthy calves is 16.8% and the average of diarrheal calves is 7.7%, when we look at the figures for the α-2 at 1-14 days, we found that healthy calves average 5.2% and diarrheal calves 8.7% higher than healthy cows. On α-1, 15-28 days, and after 28 days, healthy calves average 10.4% and diarrheal calves average 7.5% diarrhea calves were 12.6% and 12.4% higher than healthy calves. In the α-SUM, the healthy calves were 21.6%, 16.8%, and 14.5%, respectively, after 1-14 days, 15-28 days and 28 days. diarrheal calves were 23.1%, 19.5%, and 19.8%. Conclusion and Significance: In this study, we examined the electrophoresis results of healthy calves and diseased (diarrhea) calves, gamma globulin at 1-14 days of age were lower than those of healthy calves (diarrhea), indicating that the calf was unable to consume colostrum from the mother when it was a new calf. α-1, α-2, α-SUM may be associated with an acute inflammatory response as a result of increased levels of calves with diarrhea (diarrhea). Further research is needed to investigate the effects of acute inflammatory responses on additional calf-forming proteins. Information on the results of the electrophoresis test will be provided where necessary according to the item.

Keywords: alpha, electrophoretogram, serum protein, γ, gamma

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Authors: Upeksha Jayasuriya

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The sudden transition from onsite to online teaching/learning due to the COVID-19 pandemic called for a need to incorporate feasible as well as effective methods of online teaching in most developing countries like Sri Lanka. The English as a Second Language (ESL) classroom faces specific challenges in this adaptation, and teaching writing can be identified as the most challenging task compared to teaching the other three skills. This study was therefore carried out to explore the challenges of teaching writing online and to provide effective means of overcoming them while taking into consideration the attitudes of students and teachers with regard to learning/teaching English writing via online platforms. A survey questionnaire was distributed (electronically) among 60 students from the University of Colombo, the University of Kelaniya, and The Open University in order to find out the challenges faced by students, while in-depth interviews were conducted with 12 lecturers from the mentioned universities. The findings reveal that the inability to observe students’ writing and to receive real-time feedback discourage students from engaging in writing activities when taught online. It was also discovered that both students and teachers increasingly prefer Google Slides over other platforms such as Padlet, Linoit, and Jam Board as it boosts learner autonomy and student-teacher interaction, which in turn allows real-time formative feedback, observation of student work, and assessment. Accordingly, it can be recommended that teaching writing online can be better facilitated by using interactive platforms such as Google Slides, for it promotes active learning and student engagement in the ESL class.

Keywords: ESL, teaching writing, online teaching, active learning, student engagement

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Authors: Tom Nakotte, Hongmei Luo

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Lead chalcogenide-based (PbS, PbSe, and PbTe) quantum dots (QDs) were synthesized for the purpose of implementing them in radiation detectors. Pb based materials have long been of interest for gamma and x-ray detection due to its high absorption cross section and Z number. The emphasis of the studies was on exploring how to control charge carrier transport within thin films containing the QDs. The properties of QDs itself can be altered by changing the size, shape, composition, and surface chemistry of the dots, while the properties of carrier transport within QD films are affected by post-deposition treatment of the films. The QDs were synthesized using colloidal synthesis methods and films were grown using multiple film coating techniques, such as spin coating and doctor blading. Current QD radiation detectors are based on the QD acting as fluorophores in a scintillation detector. Here the viability of using QDs in solid-state radiation detectors, for which the incident detectable radiation causes a direct electronic response within the QD film is explored. Achieving high sensitivity and accurate energy quantification in QD radiation detectors requires a large carrier mobility and diffusion lengths in the QD films. Pb chalcogenides-based QDs were synthesized with both traditional oleic acid ligands as well as more weakly binding oleylamine ligands, allowing for in-solution ligand exchange making the deposition of thick films in a single step possible. The PbS and PbSe QDs showed better air stability than PbTe. After precipitation the QDs passivated with the shorter ligand are dispersed in 2,6-difloupyridine resulting in colloidal solutions with concentrations anywhere from 10-100 mg/mL for film processing applications, More concentrated colloidal solutions produce thicker films during spin-coating, while an extremely concentrated solution (100 mg/mL) can be used to produce several micrometer thick films using doctor blading. Film thicknesses of micrometer or even millimeters are needed for radiation detector for high-energy gamma rays, which are of interest for astrophysics or nuclear security, in order to provide sufficient stopping power.

Keywords: colloidal synthesis, lead chalcogenide, radiation detectors, quantum dots

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Authors: Kingsley Okoro Nwannennaya

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The 21st century seems to have been eclipsed by social conflict, giving vent to a mentality construct that accepts conflict as inextricable part of the social system. This is justified by the escalation of conflict in all the zones of the world. We therefore, query whether a peaceful society is a mere illusion? It is in an attempt to give lucid answer to this question that the researcher began critical investigations on various peace building and conflict management models. Here the researcher discovered that these models as good as they may be have not addressed the root of conflicts which revolves on the social structure in place in any society. Hence the current social structure is organized around class system, which gave birth to competition, greed, selfishness, power struggle etc. and also promotes mono-culture based on Euro-American traditions. This placed some cultures on a disadvantageous position, with conflict as its outgrowth. However, the researcher being interested to finding a peace building and conflict management model that will address this gap discovered that Taoism has the seed that can offer the world the desired peace. This tradition anchors on the principles of Tao, Yin-yang and Wu-wei. Basic to the trio concepts are the idea of Pluralism, non-interference, non-action and flowing with the order of nature. This paper, having adopted, historical and sociological methods of investigations opines that if Taoist tradition shall be adopted as a peace building model, the desired peace of our dream shall soon become a reality.

Keywords: critical option, oriental traditions, peace initiative, taoism

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Authors: Deeman Yousif Mahmood, Mohammed Abdullah Hussein

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The goal of a network-based intrusion detection system is to classify activities of network traffics into two major categories: normal and attack (intrusive) activities. Nowadays, data mining and machine learning plays an important role in many sciences; including intrusion detection system (IDS) using both supervised and unsupervised techniques. However, one of the essential steps of data mining is feature selection that helps in improving the efficiency, performance and prediction rate of proposed approach. This paper applies unsupervised K-means clustering algorithm with information gain (IG) for feature selection and reduction to build a network intrusion detection system. For our experimental analysis, we have used the new NSL-KDD dataset, which is a modified dataset for KDDCup 1999 intrusion detection benchmark dataset. With a split of 60.0% for the training set and the remainder for the testing set, a 2 class classifications have been implemented (Normal, Attack). Weka framework which is a java based open source software consists of a collection of machine learning algorithms for data mining tasks has been used in the testing process. The experimental results show that the proposed approach is very accurate with low false positive rate and high true positive rate and it takes less learning time in comparison with using the full features of the dataset with the same algorithm.

Keywords: information gain (IG), intrusion detection system (IDS), k-means clustering, Weka

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Authors: A. Bouriche, D. Merah, L.Alachaher-Bedjaoui, U. Maschke

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Intensive research continues in the field of liquid crystals (LCs) for their potential use in modern display applications. Nematic LCs has been most commonly used due to the large birefringence and their sensitivity to even weak perturbation forces induced by electric, magnetic and optical fields. Polymer dispersed liquid crystals (PDLCs), composed of micron-sized nematic LC droplets dispersed in a polymer matrix is an important class of materials for applications in different domains of technology involving large area display devices, optical switches, phase modulators, variable attenuators, polarisers, flexible displays and smart windows. In this study the composites are prepared from mixtures of monofunctional acrylic monomers, (Butylacrylate (ABu), 2-Ethylhexylacrylate (2-EHA), 2-Hydroxyethyl methacrylate (HEMA) and hydroxybutylmethacrylate (HBMA)) and two liquid crystals: (4-cyano-4'-n-pentyl-biphenyl) (5CB) and E7 which is an eutectic mixtures of four cyanoparaphenylenes. These mixtures are prepared adding the Darocur 1173 as photoinitiateor, the 1.6-hexanediol diacrylate (HDDA) as cross-linker agent, and finally they are exposed to UV irradiation. The kinetic polymerization of monomer/LC mixture were investigated with the Fourier Transform Infra Red spectroscopy (FTIR). The electro-optical properties of the PDLC films were determined by measuring the voltage dependence on the transmitted light.

Keywords: acrylic monomers, films PDLC, liquid crystal, polymerisation

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Authors: Asep Sukohar, Ramadhan Triyandi, Muhammad Iqbal, Sahidin, Suharyani

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Introduction: Resveratrol is a class of bioactive chemicals found in melinjo, which has a wide range of biological actions. The purpose of this study is to determine the linarin content of the melinjo fraksi by using preparative-high-performance liquid chromatography (prep-HPLC). Method: Extraction used the soxhletation method with 96% ethanol solvent. Fractionation used ethyl acetate and ethanol in a ratio of 1:1. Tracing of linarin compound used prep-HPLC with a mobile phase ratio of distilled water: methanol (55: 45, v/v). The presence of linarin was detected using a wavelength of 215 nm. Fourier Transform Infrared (FTIR) was used to identify the functional groups of compound. Result: The retention time required to elute the ethyl acetate fraction was 2.601 minutes. Compound separation identification using Fourier Transform Infrared Spectroscopy - Quest Attenuated Total Reflectance (FTIR - QATR) has a similarity value range with standards from 0 to 1000. The elution results of the ethyl acetate fraction have similar values with the standard compounds linarin (668), resveratrol (578), and catechin (455). Conclusion: Tracing for active compound in the ethyl acetate fraction of Gnetum Gnemon L. using prep-HPLC showed a strong suspicion of the presence of linarin compound.

Keywords: Gnetum gnemon L., linarin, prep-HPLC, fraction ethyl acetate

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Authors: Ren Moses, Jaqueline Masaki

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This paper addresses the need for accurate and updated vehicle classification system through a thorough evaluation of vehicle class categories to identify errors arising from the existing system and proposing modifications. The data collected from two permanent traffic monitoring sites in Florida were used to evaluate the performance of the existing vehicle classification table. The vehicle data were collected and classified by the automatic vehicle classifier (AVC), and a video camera was used to obtain ground truth data. The Federal Highway Administration (FHWA) vehicle classification definitions were used to define vehicle classes from the video and compare them to the data generated by AVC in order to identify the sources of misclassification. Six types of errors were identified. Modifications were made in the classification table to improve the classification accuracy. The results of this study include the development of updated vehicle classification table with a reduction in total error by 5.1%, a step by step procedure to use for evaluation of vehicle classification studies and recommendations to improve FHWA 13-category rule set. The recommendations for the FHWA 13-category rule set indicate the need for the vehicle classification definitions in this scheme to be updated to reflect the distribution of current traffic. The presented results will be of interest to States’ transportation departments and consultants, researchers, engineers, designers, and planners who require accurate vehicle classification information for planning, designing and maintenance of transportation infrastructures.

Keywords: vehicle classification, traffic monitoring, pavement design, highway traffic

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Authors: Nusrat Praween, Krishna Thej Pammi Guru, Palash Kumar Basu

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Designing non-invasive biosensors for cancer diagnosis is essential for developing an affordable and specific tool to measure cancer-related exosome biomarkers. Exosomes, released by healthy as well as cancer cells, contain valuable information about the biomarkers of various diseases, including cancer. Despite the availability of various isolation techniques, ultracentrifugation is the standard technique that is being employed. Post isolation, exosomes are traditionally exposed to detergents for extracting their proteins, which can often lead to protein degradation. Further to this, it is very essential to develop a sensing platform for the quantification of clinically relevant proteins in a wider range to ensure practicality. In this study, exosomes were immobilized on the Au Screen Printed Electrode (SPE) using EDC/NHS chemistry to facilitate binding. After immobilizing the exosomes on the screen-printed electrode (SPE), we investigated the impact of the electric field by applying various voltages to induce exosome lysis and release their contents. The lysed solution was used for sensing TSG101, a crucial biomarker associated with various cancers, using both faradaic and non-faradaic electrochemical impedance spectroscopy (EIS) methods. The results of non-faradaic and faradaic EIS were comparable and showed good consistency, indicating that non-faradaic sensing can be a reliable alternative. Hence, the non-faradaic sensing technique was used for label-free quantification of the TSG101 biomarker. The results were validated using ELISA. Our electrochemical immunosensor demonstrated a consistent response of TSG101 from 125 pg/mL to 8000 pg/mL, with a detection limit of 0.125 pg/mL at room temperature. Additionally, since non-faradic sensing is label-free, the ease of usage and cost of the final sensor developed can be reduced. The proposed immunosensor is capable of detecting the TSG101 protein at low levels in healthy serum with good sensitivity and specificity, making it a promising platform for biomarker detection.

Keywords: biosensor, exosomes isolation on SPE, electric field lysis of exosome, EIS sensing of TSG101

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Authors: Davood Mousanezhad, Ashkan Vaziri

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As a traditional cellular structure, hexagonal honeycombs are known for their high strength-to-weight ratio. Here, we introduce a class of fractal-appearing hierarchical metamaterials by replacing the vertices of the original non-hierarchical hexagonal grid with smaller hexagons and iterating this process to achieve higher levels of hierarchy. It has been recently shown that the isotropic in-plane Young's modulus of this hierarchical structure at small deformations becomes 25 times greater than its regular counterpart with the same mass. At large deformations, we find that hierarchy-dependent elastic buckling introduced at relatively early stages of deformation decreases the value of Poisson's ratio as the structure is compressed uniaxially leading to auxeticity (i.e., negative Poisson's ratio) in subsequent stages of deformation. We also show that the topological hierarchical architecture and instability-induced pattern transformations of the structure under compression can be effectively used to tune the propagation of elastic waves within the structure. We find that the hierarchy tends to shift the existing phononic bandgaps (defined as frequency ranges of strong wave attenuation) to lower frequencies while opening up new bandgaps. Deformation is also demonstrated as another mechanism for opening more bandgaps in hierarchical structures. The results provide new insights into the role of structural organization and hierarchy in regulating mechanical properties of materials at both the static and dynamic regimes.

Keywords: cellular structures, honeycombs, hierarchical structures, metamaterials, multifunctional structures, phononic crystals, auxetic structures

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Authors: Imali T. Jayamanne, K. P. Asoka Ramanayake

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Transition from tertiary level education to employment is one of the challenges that many fresh university graduates face after graduation. The transition period or the waiting time to obtain the first employment varies with the socio-economic factors and the general characteristics of a graduate. Compared to other fields of study, Arts graduates in Sri Lanka, have to wait a long time to find their first employment. The objective of this study is to identify the determinants of the transition from higher education to employment of these graduates using survival models. The study is based on a survey that was conducted in the year 2016 on a stratified random sample of Arts graduates from Sri Lankan universities who had graduated in 2012. Among the 469 responses, 36 (8%) waiting times were interval censored and 13 (3%) were right censored. Waiting time for the first employment varied between zero to 51 months. Initially, the log-rank and the Gehan-Wilcoxon tests were performed to identify the significant factors. Gender, ethnicity, GCE Advanced level English grade, civil status, university, class received, degree type, sector of first employment, type of first employment and the educational qualifications required for the first employment were significant at 10%. The Cox proportional hazards model was fitted to model the waiting time for first employment with these significant factors. All factors, except ethnicity and type of employment were significant at 5%. However, since the proportional hazard assumption was violated, the lognormal Accelerated failure time (AFT) model was fitted to model the waiting time for the first employment. The same factors were significant in the AFT model as in Cox proportional model.

Keywords: AFT model, first employment, proportional hazard, survey design, waiting time

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Authors: Claire Griffin

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Recent years have witnessed a surge in the use of innovative teaching approaches to support student engagement and higher-order learning within higher education. This paper seeks to explore the use of collaborative, interactive teaching and learning strategies to support student engagement in a final year undergraduate Developmental Psychology module. In particular, the use of the jigsaw method, in-class presentations and online discussion fora were adopted in a ‘lectorial’ style teaching approach, aimed at scaffolding learning, fostering social interdependence and supporting various levels of student engagement in higher education. Using the ‘Student Course Engagement Questionnaire’, the impact of such teaching strategies on students’ college classroom experience was measured, with additional qualitative student feedback gathered. Results illustrate the positive impact of the teaching methodologies on students’ levels of engagement, with positive implications emerging across the four engagement factors: skills engagement, emotional engagement, participation/interaction engagement and performance engagement. Thematic analysis on students’ qualitative comments also provided greater insight into the positive impact of the ‘lectorial’ teaching approach on students’ classroom experience within higher level education. Implications of the findings are presented in terms of informing effective teaching practices within higher education. Additional avenues for future research and strategy usage will also be discussed, in light of evolving practice and cutting edge literature within the field.

Keywords: learning, higher education, scaffolding, student engagement

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Authors: Kazuma Mizukoshi

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Are electoral politics in contemporary Brazil still local in organization and focus? The importance of this question lies in its paradoxical trajectories. First, often coupled with institutional and sociological ‘barriers’ (e.g. the selection and election of candidates relatively loyal to the local party leadership, the predominance of territorialized electoral campaigns, and the resilience of political clientelism), the regionalization of electoral politics has been a viable and practical solution especially for pragmatic politicians in some Latin American countries. On the other hand, some leftist parties that once served as minor opposition forces at the time of foundational or initial elections have certainly expanded vote shares. Some were eventually capable of holding most (if not a majority) legislative seats since the 1990s. Though not yet rigorously demonstrated, theoretically implicit in the rise of leftist parties in legislative elections is the gradual (if not complete) nationalization of electoral support—meaning the growing equality of a party’s vote share across electoral districts and its change over time. This study will develop four hypotheses to explain the dynamics of party nationalization in contemporary Brazil: district magnitude, ethnic and class fractionalization of each district, voting intentions in federal and state executive elections, and finally the left-right stances of electorates. The study will demonstrate these hypotheses by closely working with the Brazilian Electoral Study (2002-2014).

Keywords: party nationalization, presidential coattails, Left, Brazil

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Authors: C. D’Urso, L. Frusteri, M. Samperi, G. Leonardi

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Solid metal halides are used as active cathode ingredients in the case of Na-NiCl2 batteries that require a fused secondary electrolyte, sodium tetrachloraluminate (NaAlCl4), to facilitate the movement of the Na+ ion into the cathode. The sodium-nickel chloride (Na - NiCl2) battery has been extensively investigated as a promising system for large-scale energy storage applications. The growth of Ni and NaCl particles in the cathodes is one of the most important factors that degrade the performance of the Na-NiCl2 battery. The larger the particles of active ingredients contained in the cathode, the smaller the active surface available for the electrochemical reaction. Therefore, the growth of Ni and NaCl particles can lead to an increase in cell polarization resulting from the reduced active area. A higher current density, a higher state of charge (SOC) at the end of the charge (EOC) and a lower Ni / NaCl ratio are the main parameters that result in the rapid growth of Ni particles. In light of these problems, cathode and chemistry Nano-materials with recognized and well-documented electrochemical functions have been studied and manufactured to simultaneously improve battery performance and develop less expensive and more performing, sustainable and environmentally friendly materials. Starting from the well-known cathodic material (Na-NiCl2), the new electrolytic materials have been prepared on the replacement of nickel with iron (10-90%substitution of Nichel with Iron), to obtain a new material with potential advantages compared to current battery technologies; for example,, (1) lower cost of cathode material compared to state of the art as well as (2) choices of cheaper materials (stainless steels could be used for cell components, including cathode current collectors and cell housings). The study on the particle size of the cathode and the physicochemical characterization of the cathode was carried out in the test cell using, where possible, the GITT method (galvanostatic technique of intermittent titration). Furthermore, the impact of temperature on the different cathode compositions of the positive electrode was studied. Especially the optimum operating temperature is an important parameter of the active material.

Keywords: critical raw materials, energy storage, sodium metal halide, battery

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Authors: Stephan Treuke

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The paper analyses the neighbourhood effects on the economic mobility of the inhabitants of three segregated communities of Salvador (Brazil), in other words, the socio-economic advantages and disadvantages affecting the lives of poor people due to their embeddedness in specific socio-residential contexts. Recent studies performed in Brazilian metropolis have concentrated on the structural dimensions of negative externalities in order to explain neighbourhood-level variations in a field of different phenomena (delinquency, violence, access to the labour market and education) in spatial isolated and socially homogeneous slum areas (favelas). However, major disagreement remains whether the contiguity between residents of poor neighbourhoods and higher-class condominio-dwellers provides structures of opportunities or whether it fosters socio-spatial stigmatization. Based on a set of interviews, investigating the variability of interpersonal networks and their activation in the struggle for economic inclusion, the study confirms that the proximity of Nordeste de Amaralina to middle-/upper-class communities affects positively the access to labour opportunities. Nevertheless, residential stigmatization, as well as structures of social segmentation, annihilate these potentials. The lack of exposition to individuals and groups extrapolating from the favela’s social, educational and cultural context restricts the structures of opportunities to local level. Therefore, residents´ interpersonal networks reveal a high degree of redundancy and localism, based on bonding ties connecting family and neighbourhood members. The resilience of segregational structures in Plataforma contributes to the naturalization of social distance patters. It’s embeddedness in a socially homogeneous residential area (Subúrbio Ferroviário), growing informally and beyond official urban politics, encourages the construction of isotopic patterns of sociability, sharing the same values, social preferences, perspectives and behaviour models. Whereas it’s spatial isolation correlates with the scarcity of economic opportunities, the social heterogeneity of Fazenda Grande II interviewees and the socialising effects of public institutions mitigate the negative repercussions of segregation. The networks’ composition admits a higher degree of heterophilia and a greater proportion of bridging ties accounting for the access to broader information actives and facilitating economic mobility. The variability observed within the three different scenarios urges to reflect about the responsability of urban politics when it comes to the prevention or consolidation of the social segregation process in Salvador. Instead of promoting the local development of the favela Plataforma, public housing programs priorize technocratic habitational solutions without providing the residents’ socio-economic integration. The impact of negative externalities related to the homogeneously poor neighbourhood is potencialized in peripheral areas, turning its’ inhabitants socially invisible, thus being isolated from other social groups. The example of Nordeste de Amaralina portrays the failing interest of urban politics to bridge the social distances structuring the brazilian society’s rigid stratification model, founded on mecanisms of segmentation (unequal access to labour market and education system, public transport, social security and law protection) and generating permanent conflicts between the two socioeconomically distant groups living in geographic contiguity. Finally, in the case of Fazenda Grande II, the public investments in both housing projects and complementary infrastructure (e.g. schools, hospitals, community center, police stations, recreation areas) contributes to the residents’ socio-economic inclusion.

Keywords: economic mobility, neighborhood effects, Salvador, segregation

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Authors: Nattawadee Sinpattanawong

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Oral presentation has been used mostly in business communication. The business presentation is carrying out through an audio and visual presentation material such as statistical documents, projectors, etc. Common examples of business presentation are intra-organization and sales presentations. The study aims at investigating functions, strategies and contents of assessors’ verbal feedback on presenters’ oral presentations and exploring presenters’ learning process and specific views and expectations concerning assessors’ verbal feedback related to the delivery of the oral presentation. This study is designed as a descriptive qualitative research; four master students and one teacher in English for Business and Industry Presentation Techniques class of public university will be selected. The researcher hopes that any understanding how assessors’ verbal feedback on oral presentations and learning process may illuminate issues for other people. The data from this research may help to expand and facilitate the readers’ understanding of assessors’ verbal feedback on oral presentations and learning process in their own situations. The research instruments include an audio recorder, video recorder and an interview. The students will be interviewing in order to ask for their views and expectations concerning assessors’ verbal feedback related to the delivery of the oral presentation. After finishing data collection, the data will be analyzed and transcribed. The findings of this study are significant because it can provide presenters knowledge to enhance their learning process and provide teachers knowledge about providing verbal feedback on student’s oral presentations on a business context.

Keywords: business context, learning process, oral presentation, verbal feedback

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Authors: K. Akutsu, S. Mori, T. Hanashima

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Fluorescent probes are useful for the selective detection of trace amount of ions and biomolecular imaging in living cells. Various kinds of metal ion-selective fluorescent compounds have been developed, and some compounds have been applied as effective metal ion-selective fluorescent probes. However, because competition between the ligand and water molecules for the metal ion constitutes a major contribution to the stability of a complex in aqueous solution, it is difficult to develop a highly sensitive, selective, and stable fluorescent probe in aqueous solution. The micelles, these are formed in the surfactant aqueous solution, provides a unique hydrophobic nano-environment for stabilizing metal-organic complexes in aqueous solution. Therefore, we focused on the unique properties of micelles to develop a new fluorescence analysis system. We have been developed a fluorescence analysis system for Sr(II) by using a Sr(II) fluorescent sensor, N-(2-hydroxy-3-(1H-benzimidazol-2-yl)-phenyl)-1-aza-18-crown-6-ether (BIC), and studied its complexation behavior with Sr(II) in micellar solution. We revealed that the stability constant of Sr(II)-BIC complex was 10 times higher than that in aqueous solution. In addition, its detection limit value was also improved up to 300 times by this system. However, the mechanisms of these phenomena have remained obscure. In this study, we investigated the structure of Sr(II)-BIC complex in aqueous micellar solution by combining use the extended X-ray absorption fine structure (EXAFS) and neutron reflectivity (NR) method to understand the unique properties of the fluorescence analysis system from the view point of structural chemistry. EXAFS and NR experiments were performed on BL-27B at KEK-PF and on BL17 SHARAKU at J-PARC MLF, respectively. The obtained EXAFS spectra and their fitting results indicated that Sr(II) and BIC formed a Sr(18-crown-6-ether)-like complex in aqueous micellar solution. The EXAFS results also indicated that the hydrophilic head group of surfactant molecule was directly coordinated with Sr(II). In addition, the NR results also indicated that Sr(II)-BIC complex would interact with the surface of micelle molecules. Therefore, we concluded that Sr(II), BIC, and surfactant molecule formed a ternary complexes in aqueous micellar solution, and at least, it is clear that the improvement of the stability constant in micellar solution is attributed to the result of the formation of Sr(BIC)(surfactant) complex.

Keywords: micell, fluorescent probe, neutron reflectivity, EXAFS

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Authors: Ali Rahnamoun, Adri van Duin

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The concept of high velocity particle impact on the spacecraft surface materials has been one of the important issues in the design of such materials. Among these particles, water clusters might be the most abundant and the most important particles to be studied. The importance of water clusters is that upon impact on the surface of the materials, they can cause damage to the material and also if they are sub-cooled water clusters, they can attach to the surface of the materials and cause ice accumulation on the surface which is very problematic in spacecraft and also aircraft operations. The dynamics of the collisions between amorphous silica structures and water clusters with impact velocities of 1 km/s to 10 km/s are studied using the ReaxFF reactive molecular dynamics simulation method. The initial water clusters include 150 water molecules and the water clusters are collided on the surface of amorphous fully oxidized and suboxide silica structures. These simulations show that the most abundant molecules observed on the silica surfaces, other than reflecting water molecules, are H3O+ and OH- for the water cluster impacts on suboxide and fully oxidized silica structures, respectively. The effect of impact velocity on the change of silica mass is studied. At high impact velocities the water molecules attach to the silica surface through a chemisorption process meaning that water molecule dissociates through the interaction with silica surface. However, at low impact velocities, physisorbed water molecules are also observed, which means water molecule attaches and accumulates on the silica surface. The amount of physisorbed waters molecules at low velocities is higher on the suboxide silica surfaces. The evolution of the temperatures of the water clusters during the collisions indicates that the possibility of electron excitement at impact velocities less than 10 km/s is minimal and ReaxFF reactive molecular dynamics simulation can predict the chemistry of these hypervelocity impacts. However, at impact velocities close to 10 km/s the average temperature of the impacting water clusters increase to about 2000K, with individual molecules oocasionally reaching temperatures of over 8000K and thus will be prudent to consider the concept of electron excitation at these higher impact velocities which goes beyond the current ReaxFF ability.

Keywords: spacecraft materials, hypervelocity impact, reactive molecular dynamics simulation, amorphous silica

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Authors: Kuan-Wei Chen, Chien-Wei Chen, Tai-Ling Chang, Nan-Cheng Chen, Ching-Lin Hsieh, Gong-Hong Lin

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Background and Purposes: Deficits in sustained attention are common in patients with schizophrenia. Such impairment can limit patients to effectively execute daily activities and affect the efficacy of rehabilitation. The aims of this study were to examine the test-retest agreement, random measurement error, and practice effect of the Continuous Performance Test-Identical Pairs (CPT-IP) (a commonly used sustained attention test) in patients with schizophrenia. The results can provide empirical evidence for clinicians and researchers to apply a sustained attention test with sound psychometric properties in schizophrenia patients. Methods: We recruited patients with chronic schizophrenia to be assessed twice with 1 week interval using CPT-IP. The intra-class correlation coefficient (ICC) was used to examine the test-retest agreement. The percentage of minimal detectable change (MDC%) was used to examine the random measurement error. Moreover, the standardized response mean (SRM) was used to examine the practice effect. Results: A total of 56 patients participated in this study. Our results showed that the ICC was 0.82, MDC% was 47.4%, and SRMs were 0.36 for the CPT-IP. Conclusion: Our results indicate that CPT-IP has acceptable test-retests agreement, substantial random measurement error, and small practice effect in patients with schizophrenia. Therefore, to avoid overestimating patients’ changes in sustained attention, we suggest that clinicians interpret the change scores of CPT-IP conservatively in their routine repeated assessments.

Keywords: schizophrenia, sustained attention, CPT-IP, reliability

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Authors: V.Barbakadze, L.Gogilashvili, L.Amiranashvili, M.Merlani, K.Mulkijanyan

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The high-molecular fractions from the several species of two genera (Symphytum and Anchusa) of Boraginaceae family Symphytum asperum, S. caucasicum, S. officinale, and Anchusa italica were isolated. According to IR, 13C and 1H NMR, 2D heteronuclear 1H/13C HSQC spectral data and 1D NOE experiment, the main structural element of these preparations was found to be a regularly substituted polyoxyethylene, namely poly[3-(3,4-dihydroxyenyl)glyceric acid] (PDPGA) or poly[oxy-1-carboxy-2-(3,4-dihydroxyphenyl)ethylene]. Such caffeic acid-derived biopolymer to our knowledge has not been known and has been identified for the first time. This compound represents a new class of natural polyethers with a residue of 3-(3,4-dihydroxyphenyl)glyceric acid as the repeating unit. Most of the carboxylic groups of PDPGA from A. italica unlike the polymer of S. asperum, S. caucasicum, and S. officinale are methylated. The 2D DOSY experiment gave the similar diffusion coefficient for the methylated and non-methylated signals of A. italica PDPGA. Both sets of signals fell in the same horizontal. This would imply a similar molecular weight for methylated and non-methylated polymers. This was further evidenced by graphic representations of the intensity decay of the 1H signals of aromatic H-2″ and H-1 at δ 7.16 and 5.24 and that of the methoxy group at δ 3.85. These three signals essentially showed the same curve shape. According to results of in vitro and in vivo experiments PDPGA of S.asperum and S.caucasicum could be considered as potential anti-inflammatory, wound healing and anti-cancer therapeutic agent.

Keywords: caffeic acid-derived polyether, poly[3-(3, 4-dihydroxyphenyl)glyceric acid], poly[oxy-1-carboxy-2-(3, 4-dihydroxyphenyl)ethylene], symphytum, anchusa

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Authors: Mustafa Abu Ghalia, Mohammed Seddik

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The design and development of a new class of biomaterial has gained particular interest in producing polymer scaffold for biomedical applications. Improving mechanical properties, biological and controlling pores scaffold are important factors to provide appropriate biomaterial for implement in soft tissue repair and regeneration. In this study, poly-ε-caprolactone (PCL) /polyethylene glycol (PEG) copolymer (80/20) incorporated with CNF scaffolds were made employing solvent casting and particulate leaching methods. Four mass percentages of CNF (1, 2.5, 5, and 10 wt.%) were integrated into the copolymer through a silane coupling agent. Mechanical properties were determined using Tensile Tester data acquisition to investigate the effect of porosity, pore size, and CNF contents. Tensile strength obtained for PCL/PEG- 5 wt.% CNF was 16 MPa, which drastically decreased after creating a porous structure to 7.1 MPa. The optimum parameters of the results were found to be 5 wt.% for CNF, 240 μm for pore size, and 83% for porosity. Scanning electron microscopy (SEM) micrograph reveals that consistent pore size and regular pore shape were accomplished after the addition of CNF-5 wt. % into PCL/PEG. The results of mass loss of PCL/PEG reinforced-CNF 1% have clearly enhanced to double values compared with PCL/PEG copolymer and three times with PCL/PEG scaffold-CNF 1%. In addition, all PCL/PEG reinforced and scaffold- CNF were partially disintegrated under composting conditions confirming their biodegradable behavior. This also provides a possible solution for the end life of these biomaterials.

Keywords: PCL/PEG, cellulose nanofibers, tissue engineering, biodegradation, compost polymers

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Authors: Barzan Hadi Hama Karim

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The topic of formative assessment and its implementation in Iraqi Kurdistan have not attracted the attention of researchers and educators. Teachers’ beliefs about formative assessment as well as their assessment roles have remained unexplored. This paper reports on the research results of our survey which is conducted in 20014 to examine issues relating to formative assessment in the university ESL classroom settings. The paper portrays the findings of a qualitative study on the formative assessment role and beliefs of a group of teachers of English as a Foreign Language (EFL) in the departments of English Languages in Iraqi Kurdistan universities. Participants of the study are 25 Kurdish EFL teachers from different departments of English languages. Close-ended and open-ended questionnaire is used to collect teacher’s beliefs and perceptions about the importance of formative assessment to improve the process of teaching and learning English language. The result of the study shows that teachers do not play a significant role in the assessment process because of top-down managerial approaches and educational system. The results prove that the teachers’ assessment beliefs and their key role in assessment should not be neglected. Our research papers pursued the following questions: What is the nature of formative assessment in a second language classroom setting? Do the teacher’s assessment practices reflect what she thinks about formative assessment? What are the teachers’ perceptions regarding the benefits of formative assessment for teaching and learning English language at the university level?

Keywords: formative assessment, teachers’ beliefs and perceptions, assessment, education reform, ESL

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Authors: Mohammad B. HabibiNajafi, Saeideh Sadat Fatemizadeh, Maryam Tavakoli

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In recent years, the consumption of functional foods, including foods containing probiotic bacteria, has come to notice. Milk proteins have been identified as a source of angiotensin-I-converting enzyme )ACE( inhibitory peptides and are currently the best-known class of bioactive peptides. In this study, the effects of adding prebiotic ingredients (inulin and wheat fiber) and fat percentage (0%, 2% and 3.5%) in yogurt containing probiotic Lactobacillus casei on physicochemical properties, degree of proteolysis, antioxidant and ACE-inhibitory activity within 21 days of storage at 5 ± 1 °C were evaluated. The results of statistical analysis showed that the application of prebiotic compounds led to a significant increase in water holding capacity, proteolysis and ACE-inhibitory of samples. The degree of proteolysis in yogurt increases as storage time elapses (P < 0.05) but when proteolysis exceeds a certain threshold, this trend begins to decline. Also, during storage time, water holding capacity reduced initially but increased thereafter. Moreover, based on our findings, the survival of Lactobacillus casei in samples treated with inulin and wheat fiber increased significantly in comparison to the control sample (P < 0.05) whereas the effect of fat percentage on the survival of probiotic bacteria was not significant (P = 0.095). Furthermore, the effect of prebiotic ingredients and the presence of probiotic cultures on the antioxidant activity of samples was significant (P < 0.05).

Keywords: probiotic yogurt, proteolysis, ACE-inhibitory, antioxidant activity

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Authors: Malik Shoeb Ahmad

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The aim of the present study is to carry out investigations on Class F fly ash obtained from NTPC thermal power plant, Dadri, U.P. (India) and electroplating waste sludge from Aligarh, U.P. (India) along with geofibre for its subsequent utilization in various geotechnical and highway engineering applications. The experimental studies such as California bearing ratio (CBR) tests were carried out to evaluate the strength of plain fly ash as well as fly ash-waste sludge mix reinforced with geofibre, as the CBR value is the vital parameters used in the design of flexible and rigid pavements. Results of the study show that the strength of the mix is highly dependent on the curing period and the sludge and geofibre content. The CBR values were determined for mix containing fly ash (83.5-93.5%), waste sludge (5-15%) and 1-2% geofibre. However, out of the various combinations of mixes the CBR value of the mix 88.5%FA+10%S+1.5%GF at 28 days of curing was found to be 53.52% when compared with the strength of plain fly ash. It has been observed that the fibre inclusion increases the strength of the plain fly ash and fly ash-waste sludge specimens by changing their brittle to ductile behavior. The TCLP leaching test was also conducted to determine the heavy metal concentration in the optimized mix. The results of TCLP test show that the heavy metal concentration in the mix 88.5%FA+10%S+1.5%G at 28 days of curing reduced substantially from 24 to 98% when compared with the concentration of heavy metals in the waste sludge collected from source. It has also been observed that the pH of the leachate of this mix is between 9-11, which ensures the proper stabilization of the heavy metals present in the mix. Hence, this study will certainly help in mass scale utilization of two industrial wastes viz., electroplating waste and fly ash, which are causing pollution to the environment to a great extent.

Keywords: Dadri fly ash, geofibre, electroplating waste sludge, CBR, TCLP

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Authors: Liu Jiaxin

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This paper seeks to do an in-depth investigation on the phenomenon of Early Modern era (1500-1700s) Livonian werewolves. Noting their uniqueness in comparison to contemporaneous werewolves hailing from other geographic areas, the paper suggests that the Livonian werewolf is a metaphor for Livonian society at that time, one which was characterized by social turmoil and strict class hierarchy. This metaphor was utilized by different classes to establish their own interests in society, and thus the paper concludes that the werewolf is a mutable artifact whose value is contingent on its social context. This is demonstrated by the particular case of Old Thiess—a poor, elderly Livonian peasant who gave an unorthodox and anomalous testimony when accused of being a werewolf. In his court statement, it is shown how Thiess was, in fact, alluding to social tensions by lambasting the rich German elite and establishing the righteousness of the peasantry, of which he was a member. A close reading method was utilized on the trial transcript of Old Thiess with heavy reference to Carlo Ginzburg and Bruce Lincoln’s collaborative work Old Thiess, a Livonian werewolf: a classic case in comparative perspective. Through a contextual reading of Livonia’s social atmosphere, the paper draws connections between the content of the trial to wider societal disturbances happening at the time. The thesis—that the werewolf is a flexible metaphor for the social milieu—is further buttressed by numerous contemporaneous sources that had similar messages as Thiess’ transcript, which are discussed as well.

Keywords: early-modern baltic, Livonia, Old Thiess, social history, werewolves

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Authors: Sonia Arradaza-Pajaron, Maria Aida Manila

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Teaching is considered the noblest yet believed to be one of the most complicated and challenging professions. Along this view, every teacher-producing institution should look into producing quality pre-service graduates who are efficacious enough with the right attitude and to deal with the task accorded to them. This study investigated the association between self-efficacy and attitude of graduating pre-service teachers with their actual student teaching performance. Survey questionnaires on self-efficacy and attitude toward practice teaching were fielded to the 90 actual respondents while their practice teaching grade was extracted to serve as the other main variable. Data were analyzed and treated statistically utilizing weighted mean and Pearson r to determine the relationship of variables of the study. Findings revealed that attitude of respondents of the three curricular programs was favorable, and they are self-efficacious. Their practice teaching performance was interpreted as very good. Results further showed a significant positive relationship between their self-efficacy and practice teaching performance. It showed that their rating was a manifestation of self- efficacious group. Although they exude positive attitude towards practice teaching, yet no significant relationship was seen with their attitude and performance. Moreover, data manifested that most of them can pay attention during their conduct of lessons in the class, as well as, listen attentively to their cooperating teachers during post conferences. They can perform student teaching tasks better even when there were other interesting things to do. Most of all, they can regulate or suppress not so pleasant thoughts or feelings and take things lightly even in most challenging situations. As gleaned from the results, it can be concluded that there was an association between self-efficacy and practice teaching performance of the respondents.

Keywords: academic achievement, attitude, self-efficacy, student teaching performance

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