bluuebunny/crossref_metadata_2025 huggingface dataset:
The Need for a School-based Student Obesity Prevention Program: Perceptions of Rural Elementary Principals
Authors: Armstrong Travis D. , Msengi Clementine , Harris Sandra
Published: July 2019

This phenomenological study investigated the perceptions of elementary principals regarding the need for a school-based student obesity prevention at eight, rural elementary schools in North Central Texas. Face to face interviews were the primary method of data collection from the eight participants. Findings indicated that school-based obesity prevention programs are needed to decrease the occurrence of student obesity, improve student diets and health related behaviors, educate families on obesity prevention measures, and improve the academic performance of students. The need to inform and include relevant stakeholders in the creation and implementation of school-based obesity prevention programs was identified as an essential component to the success of the program. The findings provide school leaders with components needed for an effective school-based obesity prevention program along with barriers for consideration.
Policy Brief: Possible Changes to Health Coverage of Rural Children Should Concern Educators
Authors: Grace Cathy
Published: July 2019

Policy Brief
I’m Paying the Time for Someone Else’s Crime: Principals and Core Teachers at Rural Middle Schools under Chronic Academic Stress
Authors: Sanchez Jafeth E. , Usinger Janet , Thornton Bill , Sparkman William
Published: July 2019

Today, many principals are assigned to struggling schools with the mandate to quickly change the academic trajectory of the students. Interviews were conducted to gain an understanding of how principals and core teachers working at rural middle schools under chronic academic stress perceived the increased academic expectations at their schools. Three key findings were revealed: (a) There were misaligned principal and teacher interpretations of efforts to improve the school; (b) there tended to be an ongoing focus on what was wrong with the school; and (c) principals felt they were alone in the process. A discussion of these findings is provided.
Left Behind by Policy: A Case Study of the Influence of High Stakes Accountability Policy on Data-Based Decision Making in One Small, Rural New Hampshire School
Authors: Carrier Linda L. , Whaland Michael
Published: July 2019

The high-stakes accountability policies that stemmed from NCLB and Race to the Top required minimum group sizes in order for school performance to be analyzed through state accountability formulas. Small rural schools have frequently been left out of this equation due to a lack of consistently reportable aggregate groups and sub-groups. The evidence of this has been seen through the lack of needed data-based decision making (DBDM) practices. In order to begin to understand the DBDM practices of small rural schools and the relationship to educational policy we engaged in case study research of a Pk-12 school of 100 students from 2014-2015. The school, located in New Hampshire, provided us with insights into the potential gaps that exist between policy and practice in small rural schools. In addition, questions of educational equity began to emerge as we considered the gaps between student achievement data and the professional development of educators.
Safety at Schools: Identifying the Costs Associated with the Necessary Safeguards for Arming Educators
Authors: Weiler Spencer C. , Cornelius Luke , Skousen Jacob D.
Published: July 2019

Editors’ note: The Rural Educator publishes a policy brief each issue, intended to explore topics pertinent to rural education policy and advocacy. The issue of school safety is particularly timely, especially for rural schools. We believe this essay, based on surveys of school leaders in Colorado, takes a unique perspective by examining the financial costs that might be associated with policies to place guns in schools.
Impact of Multiplex Relationships on Rural Science Education
Authors: Knutson Peter , Del Carlo Dawn
Published: July 2019

Relationships play a strong role in rural communities and education, and multiplex relationships – relationships that can overlap due to multiple contexts of interaction in a rural school – are unique to the rural setting. This study focused on multiplex relationships and their impact on science classroom performance, as measured by science standardized test scores, through the lens of Social Capital Theory. Quantitative survey results from rural science teachers regarding number of student relationships and state-based science test scores were correlated.  Additionally, qualitative survey answers from a subset of respondents were used to construct a more complete picture of the essence of these relationships and their perceived impacts. Results indicate multiplex relationships do not impact science test score achievement however, teacher accounts of classroom experiences with students illustrate a strong perception that multiplex relationships increase their ability to help students succeed.
What Counts as Evidence in Rural Schools? Evidence-Based Practice and Practice-Based Evidence for Diverse Settings
Authors: Eppley Karen , Azano Amy Price , Brenner Devon G. , Shannon Patrick
Published: July 2019

This policy breif examines the importance of practice-based evidence for rural education.
San Agustín: profesor, maestro, pedagogo
Authors: Jiménez Sanz Donato
Published: July 2019

Este artículo abordará la vida de san Agustín como profesor, maestro y pedagogo. El autor afirmará sobre el santo que aprender y enseñar fue la actividad de su vida. Aprender para enseñar y enseñar para aprender. El texto se enriquece a través de diferentes citas en latín provenientes de la producción agustiniana.
Manolo Fernández Díaz. Laboratorio FARVET
Authors: Muñoz Marticorena William
Published: July 2019

Este trabajo fue realizado sobre la base de entrevistas y recopilación de información durante el año 2005. A través de un repaso por la vida y logros del médico veterinario Manolo Fernández Díaz, el autor del texto logrará presentarnos a un personaje dueño de una gran humanidad, una pasión por lo que se desea, una constancia y tesón en el trabajo y una gran agudeza para visualizar las oportunidades y saber tomar riesgos. Entre los frutos de dichos esfuerzos, tendrá una especial mención el reputado Laboratorio FARVET.
Referentes en la construcción de un test de interés lector
Authors: Neyra Reátegui Hilda
Published: July 2019

La autora del texto hará una detallada exposición acerca de las motivaciones y la propia elaboración de un test de ineterés lector. Así, mostrará su preocupación por la dificultad que enfrentan los maestros peruanos para inculcar en los niños el interés por la lectura. De igual modo, las tres dimensiones relacionadas a la elaboración de la prueba radicarán en el entorno-hogar, el entorno-escuela y la competencia como niño-lector. Cabe agregar que el texto presentará el modelo del test mencionado.
Huge Lipoma Involving Left Cheek Region: A Case Report
Authors: Jamal Muhammad , Ullah Kaleem , Saher Laiba
Published: July 2019

Lipomas are very common benign lumps that can be encountered in any part of the body but a small proportion present in the head and neck region. In this case report we have discussed the diagnosis and surgical treatment of an asymptomatic huge lipoma of left cheek. The patient had this swelling present for the last 5 years. Initially there was a slight increase in the size of the swelling but since the last 3 years there is no change in size. There was no history of associated pain and tenderness. The patient had esthetic concerns because of which the lesion was excised. These lipomas continue to grow slowly, showing variable signs including dysphagia, dyspnea, and dysphonia due to the compressing effect on surrounding structures. It can also be a matter of cosmetic concern. With this case report, authors will also highlight the diagnostic modalities and treatment for lipomas occurring in unusual areas in the body. It is a rare finding that occurs anterior to parotid but can be treated successfully by current surgical approach.Key Words:, ,
Satisfacción laboral en docentes de medicina de una universidad peruana
Authors: Challco-Dávila Laurie S. , Robles-Flores Henrry J.
Published: July 2019

Introducción: Numerosos estudios indican que la satisfacción en el trabajo es una dimensión de la gestión de calidad y que existen factores capaces de mejorarla. Por otra parte, está demostrado que existe una fuerte relación entre la alta satisfacción laboral y otros factores motivadores del trabajador, como son la organización y la gestión del cambio, la percepción de la dirección o la relación jerárquica. Método: Se realizó un estudio observacional, descriptivo, prospectivo y transversal, de diseño correlacional en 60 docentes de la escuela académica profesional de medicina humana de la Universidad Nacional Hermilio Valdizán de Huánuco. Resultados: Encontramos que, en relación al tipo de contrato, 33 (55%) docentes son contratados y 27 (45%) docentes son nombrados. Así mismo el total de los docentes no están conformes con el salario que reciben por su labor como docentes. Existe asociación entre la carga laboral y la satisfacción laboral en los docentes de la Facultad de Medicina. Conclusión: No existe asociación entre el reconocimiento y la satisfacción laboral en los docentes de la Escuela Profesional de Medicina Humana. Tampoco se evidencio asociación entre la remuneración laboral y la satisfacción laboral en los docentes. Existe asociación entre la carga laboral y la satisfacción laboral en los docentes de la Facultad de Medicina Humana de la Universidad Nacional Hermilio Valdizán.
Identifikasi Ektoparasit Pada Ikan Koi (Cyprinus carpio) Di Makassar
Authors: Bunga Margaretha , Achmad Marlina
Published: July 2019

Penelitian bertujuan untuk mengidentifikasi ektoparasit pada ikan mas koi (Cyrinus carpio) di Makassar. Penelitiandilakukan dengan pengambilan sampel sebanyak tiga kali di bulan April hingga Mei 2017. Sampel ikandimasukkan ke dalam kantong plastik yang telah diisi dengan oksigen. Jumlah sampel adalah 45 ikan denganpanjang 5,5-11,8 cm dan berat 5,12 – 13,2 g. Identifikasi parasit dan penghitungan jumlah parasit dilakukan diLaboratorium Parasit dan Penyakit Ikan, Departemen Perikanan, Fakultas Ilmu Kelautan dan PerikananUniversitas Hasanuddin. Data dianlaisis secara deskriptif. Serangan ektoparasit menyerang ikan koi di bagianinsang yakni 34,21%, sirip dorsal 34,21%, dan pada mukus mengandung 31,58%.Kata kunci : ektoparasit, identifikasi, ikan koi
Effectiveness of Addition Papain Enzyme in Artificial Diet on the Metamorphosis Rate and Glycogen Content of Mangrove Crab Larvae (Scylla olivacea)
Authors: Haryati Haryati , Fujaya Yushinta , Saade Edison , Fajrianti Dwi
Published: July 2019

In the rearing of fish larvae, artificial feed can be given when digestive enzymes have been produced. To improve the ability of fish larvae to utilize artificial feeds can be done with the addition of exogenous enzyme into the artificial feeds. The aim of this study was to determine the dose of papain enzyme and the correct predigest artificial feeding stadium on metamorphosis rate and glycogen content of mangrove larvae (Scylla olivacea). The experimental design used was a factorial pattern with a complete randomized baseline design, the first factor being the dose of papain enzyme (0%, 1.5%, 3.0% and 4.5%), while the second factor was the predigest artificial feeding stage (zoea 2 and 3).  The results showed that the difference of dose of papain enzyme and predigest artificial feeding stages had significant effect (p <0.05) on the metamorphosis rate of  7, 9, 10, 12, 13, 16 and 17 day larvae, but the interaction between them was not significant (p>0,05). The rate of metamorphosis at doses of enzyme papain was 0% and 1.5% longer and significantly different (p <0.05) compared to 3% and 4.5% doses. The rate of metamorphosis at doses of 3.0% and 4.5% was not significantly different (p> 0.05). The content of glycogen larvae in dose of enzyme papain 4,5% not different than dose 1,5% and 3,0% but higher and significantly different than dose 0%. Glycogen content at dose 0%, 1,5% and 3,0%. was not significantly different (p> 0.05). Based on the results of these studies to hydrolyze feed proteins can be used papain enzyme with a dose of 4.5%.Keywords: papain enzyme, metamorphosis rate, mangrove crab larvae (Scylla olivacea), glycogen content
Potencial utilization of skipjack tuna (Katsuwonus pelamis) in Bone Bay
Authors: Umar Moh. Tauhid , Safruddin Safruddin , Zainuddin Mukti
Published: July 2019

The skipjack tuna (Katsuwonus pelamis) resource in Bone bay has long been exploited, but information about the sustainable potential of this fish resource in Bone bay waters is still very limited. The aim of this research is to estimate potential of fish resources that include catch per unit effort (CPUE ), the maximum sustainable yield (MSY), optimum effort, exploitation rate and total allowable catch (TAC) of skipjack tuna in the waters of Bone bay. This study uses time series data, namely annual data from the fisheries statistics report at Marine and Fisheries Service, South Sulawesi Province from 2006-2015. The method used to estimate the potential of fish resources in this study is the surplus production method with the Schaefer model. The results showed that the average production and standard efforts in the 10-year period were 14689.7 tons and 914 standard units respectively. The estimation results obtained MSY and optimum effort per year are 22561.4 tons and 1730 standard units, and allowed catches (TAC) of 18049.2 tons per year. The level of exploitation of skipjack tuna resources in the waters of Bone Bay does not over exploited every year except in 2017.Keywords: potential of fish resources, skipjack tuna (Katsuwonus pelamis), MSY, TAC, Bone bay
World Economic Forum & its Organization, Membership & Activities
Authors: Agarwal Satish Chandra
Published: July 2019

The World Economic Forum (WEF), based in Colony-Geneva, Switzerland, was founded in 1971 as a not-for-profit organization. It gained formal status in January 2015 under the Swiss Host-State Act, confirming the role of the Forum as an International Institution for Public-Private Cooperation. The Forum's mission is cited as "committed to improving the state of the world by engaging business, political, academic, and other leaders of society to shape global, regional, and industry agendas".
Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage
Authors: Reen Gagandeep Kour , Kumar Ashok , Sharma Pratibha
Published: July 2019

A comprehensive account of recent advances in the synthesis of imidazopyridines, assisted through transition-metal-catalyzed multicomponent reactions, C–H activation/functionalization and coupling reactions are highlighted in this review article. The basic illustration of this review comprises of schemes with concise account of explanatory text. The schemes depict the reaction conditions along with a quick look into the mechanism involved to render a deep understanding of the catalytic role. At some instances optimizations of certain features have been illustrated through tables, i.e., selectivity of catalyst, loading of the catalyst and percentage yield with different substrates. Each of the reported examples has been rigorously analyzed for reacting substrates, reaction conditions and transition metals used as the catalyst. This review will be helpful to the chemists in understanding the challenges associated with the reported methods as well as the future possibilities, both in the choice of substrates and catalysts. This review would be quite appealing to a wider range of organic chemists in academia and industrial R&D sectors working in the field of heterocyclic syntheses. In a nutshell, this review will be a guiding torch to envisage: (i) the role of various transition metals in the domain dedicated towards method development and (ii) for the modifications needed thereof in the R&D sector.
Kinetic Theory of Ion Acoustic Waves Observed at Comet 67P/Churyumov–Gerasimenko
Authors: Rehman Saeed ur , Shah Asif , Haque Qamar ul
Published: July 2019

This work presents the resonance interaction of ion acoustic waves with the cometary plasma as observed at comet 67P/Churyumov–Gerasimenko. The plasma is comprised of cold, warm, and suprathermal electron populations and water ions such that the quasineutrality is satisfied. The cold electron population is found to play a dominant role in the damping of the waves, and its maximum Landau damping rate is observed when it is 2% of the total electron density in the system. It is determined that lowering the cold electron density supports the current-driven ion acoustic instability at a relatively lower drift speed of the warm and suprathermal electron species. In the absence of cold electrons, the wave phase speed does not change by populating the high-energy suprathermal electron species, therefore, the Landau damping rate of both warm and suprathermal electrons increases by increasing their respective densities. The growth rate of the current-driven ion acoustic instability decreases by elevating the concentration of suprathermal electrons in the case of drifting warm and stationary suprathermal electrons. In the case of stationary warm and drifting suprathermal electrons, the elevated density of suprathermal electron instead favors the instability.
Influence of Thermomechanical Treatment on the Mechanical Behavior of Protaper Gold versus Protaper Universal (A Finite Element Study)
Authors: Galal Manar , Ismail Amira Galal , Omar Nada , Zaazou Mohamed , Nassar Mohamed Abdallah
Published: July 2019

AIM: To compare and evaluate the influence of thermomechanical treatment of Protaper Gold file versus Protaper Universal file during testing of bending and torsion using finite-element analysis.
METHODS: Two nickel-titanium NiTi rotary files (ProTaper Gold and ProTaper Universal) were used in this study. The files were imaged using stereomicroscope to produce 3D models. The behaviour of the instrument during bending and torsion was numerically analysed in CAD/CAM software package.
RESULTS: Under bending, ProTaper, Gold showed higher flexibility and flexural resistance than ProTaper Universal. The highest stress was related at the cutting edge of both files. While during testing of torsion, the maximum amount of stresses was related to the base of the flutes in both files. ProTaper Gold showed higher torsional resistance than the ProTaper Universal file.
CONCLUSION: Thermomechanical treatment improved the mechanical response (bending and torsional resistance) of NiTi files.
Giant Cell Tumor of Soft Tissue: A Rare Entity
Authors: Mavrogenis Andreas F. , Tsukamoto Shinji , Antoniadou Thekla , Righi Alberto , Errani Costantino
Published: July 2019

Giant cell tumor (GCT) of the soft tissue (GCT-ST) is a rare, unusual primary soft tissue tumor that is completely distinct from, and should not be confused with, any giant cell–rich tumor of bone or soft tissue. Currently, GCT-ST is included in the group of so-called fibrohistiocytic tumors of intermediate (borderline) malignancy. The most common symptom is a painless, slow-growing mass in a superficial location. Computed tomography and magnetic resonance imaging show a solid, nonhomogeneous, frequently hemorrhagic mass. Differential diagnosis is broad and should include benign and malignant entities. The treatment and excision margins of GCT-ST are controversial. Incomplete surgical excision is usually followed by local recurrence. Biological behavior is unpredictable. Giant cell tumor of the soft tissue has shown a lower mean local recurrence rate compared to GCT of bone but has a higher metastatic and death rate. Therefore, close clinical follow-up is recommended. [
Orthopedics
. 2019; 42(4):e364–e369.]
Controversies in the Management of Cervical Spine Conditions in Elite Athletes
Authors: Pahapill Richard R. , Hsu Wellington K.
Published: July 2019

Cervical spine injuries in elite athletes can have detrimental consequences, which makes return to play for professional athletes after cervical spine injury controversial. Although most athletes can return to sport under some circumstances, such as single-level anterior cervical diskectomy and fusion for cervical disk herniation, return to play after cervical disk arthroplasty and multilevel fusion for cervical disk herniation remains controversial. Allowing athletes to return to play after a finding of cervical stenosis and in the incidence of pseudarthrosis remains unclear. This review provides a systematic framework to guide return-to-play decision-making in common cervical conditions in elite athletes. [
Orthopedics
. 2019; 42(4):e370–e375.]
Monitoring of the enzymatic activity of intracellular lipases of Ustilago maydis expressed during the growth under nitrogen limitation and its correlation in lipolytic reactions
Authors: Araiza-Villanueva M. G. , Olicón-Hernández D. R. , Pardo J. P. , Vázquez-Meza H. , Guerra-Sánchez G.
Published: July 2019

Under nitrogen starvation, Ustilago maydis forms lipid droplets (LDs). Although the dynamics of these organelles are known in the literature, the identity of the lipases implicated in their degradation is unknown. We determined lipase activity and identified the intracellular lipases expressed during growth under nitrogen starvation and YPD media by zymograms. The results showed that cytosolic extracts exhibited higher lipase activity when cells were grown in YPD. Under nitrogen starvation, lipase activity was not detected after 24 h of culture, resulting in lipid accumulation in LDs. This suggests that these lipases could be implicated in LD degradation. In the zymogram, two bands, one of 25 and the other of 37 kDa, presented lipase activity. The YPD extracts showed lipase activity in olive and almond oils, which contain triacylglycerols with mono and polyunsaturated fatty acids. This is the first report about U. maydis cytosolic lipases involved in LD degradation.
Récit et mobilité empathique
Authors: Rabatel Alain
Published: July 2019

Pour tirer parti des récits, qui, dans leur diversité, présentent des dimensions anthropologiques et politiques fondamentales, concernant le soi et le nous, articulées avec les formes de sensibilité, d’éthique et d’esthétique, l’article examine la diversité des modes d’appropriation empathique – qu’il distingue de la notion de sympathie –, somatifs, imaginatifs, correspondant à des changements projectifs de place. L’article explore ensuite systématiquement la notion de mobilité empathique, activité omnidirectionnelle car on peut imaginer les perceptions, les pensées, les émotions, les paroles, les actions des autres, se mettre à la place d’individus, de groupes, réfléchir en changeant de cadre notionnel ou de valeurs de référence : cette diversité des modes d’empathisation permet aux sujets lecteurs (futurs citoyens) d’élargir leurs capabilités en améliorant leur saisie compréhensive de l’altérité, du divers, du complexe, tant sur les plans linguistique et narratologique que sur le plan mondain.
Je compris que vous conjecturiez…
Authors: Privat Jean-Marie
Published: July 2019

La nouvelle de J. L. Borges – « La mort et la boussole » (Fictions, 1942) – met en conflit mortel un détective inscrit dans la filiation du roman policier classique – « un pur raisonneur » – et un tueur qui obéit – entre autres – à la loi implacable des petites sociétés à honneur (la fratrie, le sang, les morts). Notre étude ethnocritique vise à montrer comment une affiliation à des cosmologies contradictoires (monde de la raison graphique/monde de la pensée sauvage) trouve sa résolution fatale dans l’intelligence rusée du bandit d’honneur maitre en mètis. Notre lecture s’éloigne donc des lectures marquées d’un certain formalisme narratologique. L’analyse de quelques cas concrets d’hétérophonie culturelle et narrative permet de pointer en quelle façon une herméneutique lettrée traditionnelle fait obstacle à une interprétation anthropologique du récit, son architecture, ses valeurs, ses croyances.
Ne pas (se) raconter d’histoires
Authors: Lacoste Charlotte
Published: July 2019

Partant du constat qu’une partie de la littérature française contemporaine s’élabore à la fois dans un refus de la fiction et dans une critique du récit au profit d’une écriture factualiste qui déjoue la mise en intrigue, cet article fait l’hypothèse d’une extension à la vie quotidienne de ce que le genre du témoignage avait introduit en littérature : une tentative d’objectivation des données de l’expérience personnelle visant à documenter la vie réellement vécue. Les auteur·rice·s des œuvres analysées ici consignent et archivent des faits qu’ils attestent afin de les rendre imprescriptibles, contribuant par là même à la remise en cause d’une certaine idée de la littérature dont le champ reste tributaire.
Becoming Morse in Endeavour: the prequel as locus of reconstruction of the past?
Authors: Parey Armelle
Published: July 2019

This paper examines Endeavour (ITV, 2012-), a prequel to Colin Dexter’s and ITV’s Inspector Morse (1987-2000), which was initially aired in 2012 for the 25th anniversary of Morse’s first TV appearance. This new series introduced the audience to young Morse, played by Shaun Evans, at the time of his first years as police in Oxford. In so doing, the prequel reconstructs the past on the basis of threads in the source narrative. After discussing the specificities of the prequel genre in relation to Endeavour, this paper purports to examine the transformative effects of this reconstruction: how the prequel may or may not reconstruct the past of the hero, and how in so doing it may also reconstruct the memory of the viewer, his or her perception of the past, in terms of the source narrative.
An Adult-Learner Approach to the Learning Design of Safety Management System Training in Aviation
Authors: Torrisi-Steele Geraldine , Carim Jr. Guido
Published: July 2019

The goal of training is to improve employee performance, and ultimately support organizational success. However, training does not always effectively transfer to workplaces to positively affect work practices, particularly because of disconnect between behaviourist approaches and contemporary work arrangements. The transfer of training to the workplace remains problematic. The present article is motivated by the need to challenge the status quo of training design and draw greater attention to learning design, beyond the confines of behaviourism. The aim of the article is to provoke critical discussion around learning theories and training design. We propose Knowles' adult learning principles and Mezirow's transformative learning theory, useful guide for the learning design of training. The learning design of a university-based safety management systems training course in aviation is discussed from the vantage point of the proposed guiding philosophy. Six specific strategies are presented supported by the evaluation of the course effectiveness conducted after the first iteration.
Creating a Scale for Service
Authors: Plante Jarrad D. , Bryer Thomas A , Winston Haley G.
Published: July 2019

This article presents a model that is based on Eyler and Giles' Five Elements of Citizenship, where students learn about Volunteer UCF through marketing strategies, participate in one-time service or educational events, and then pursue continuous involvement based on their positive experiences. Students transition to leadership roles by serving on a social topic committee and move up to social topic director managing their own committee. Some students aspire to be an administrative student leader and incorporate large-scale institutional projects and events. The final stage for students is committing to lifelong community engagement opportunities post-graduation. The results will inform where the touch points are at the higher education institution, so administrators can apprise bureaucracy and cultural barriers to help students progress through the scale for service within the continuum.
Qualitative Research In Online Language Learning: What Can It Do?
Authors: Stickler Ursula , Hampel Regine
Published: July 2019

This article explores the theoretical foundations of qualitative research in online language learning. It will look at the distinction between offline and online language learning and discuss whether different ways of knowledge generation are appropriate for those different learning environments. Quantitative and qualitative methodologies will be examined and their fit with various learning theories evaluated. Fundamental theoretical differences between epistemologies supporting a realist ontology and those favouring relativist ontologies will be presented and set in the context of online language learning research. Finally, an argument will be presented that in a sociocultural framework, going beyond quantitative research approaches is necessary to adequately understand the experiences of learners and teachers who share a common interest in novel digital environments.
A Framework Model for Integrating Social Media, the Web, and Proprietary Services Into YouTube Video Classification Process
Authors: Alsafrjalani Mohamad Hammam
Published: July 2019

Online video streaming has gained ubiquity in disparate educational, governmental, and corporate environments. The ubiquity of these videos elicits new challenges in video classification that is used to promote relative videos and block unwanted content. These challenges include the incorporation of contextual information, rapid development of the ad-hoc query modules, and keeping pace with contemporary contextual information. In this article, the authors present a framework model for incorporating contextual information into video classification information. To illustrate the model, the authors propose a framework which comprises video classification, web search engines, social media platforms, and third-party classification modules. The modules enable the framework's flexibility and adaptivity to different contextual environment—educational, governmental, and corporate. Additionally, the model emphasizes standardized module interface to enable the framework's extensibility and rapid development of future modules.
Empirical Research on the Profitability of R&D Expenditure
Authors: Yamada Hirokazu , Nakayama Yuji
Published: July 2019

Yamada and Nakayama (2018) estimated the profitability of research and development (R&D) expenditures for the Japanese manufacturing industry, using industry-level data. The results of the manufacturing industry are not necessarily reflective of the state of each individual firm. The purpose of this study is to understand the present state of profitability of R&D expenditures in major Japanese textile firms using firm-level financial data. In terms of methodology, a cost-effectiveness model that considers endogeneity between revenue and R&D expenditure, as well as methods from the literature that can be used to analyze even small samples, are used. The methods used in this article will help practitioners better understand the specific circumstances of their own firms. The authors' work quantifies the investment levels of R&D expenditure, presents strategic management challenges around R&D expenditure to advocate for the consideration of rates of return, and urges the establishment of management accounting criteria at the firm level.
An Investigation on Practical Information Disclosures by Non-Profit Organizations in China
Authors: Kojima Hirofumi , Wang Qiuju , Tsuji Mineo
Published: July 2019

Changes in the social environment have made the people's needs of public services present-day in China. However, the needs are so large that the government cannot always answer such needs on its own account. Therefore, a non-profit organization (NPO) is expected to solve this problem. Here, NPOs should appropriately provide the information that meets the needs of their stakeholders. Such information could establish trust in their management just like the business enterprises. Most of items regard the Foundation Transparency Index (FTI) as an indicator concerning the quality of NPOs' information disclosure. However, the quality should be embodied not only in the completeness but also in the accuracy and the timeliness. The article deals with the case of China Charities Aid Foundation for Children (CCAFC) which got the full-mark of FTI. It focuses on researching the information disclosure practice by CCAFC from 2010 to 2017. It finds out that though the CCAFC got the full-mark, the information disclosure still has problems not only in the completeness but also in the accuracy.
Repeatability of Epitaxial Growth of n-Type 4H-SiC Films by High Speed Wafer Rotation Vertical CVD Tool
Authors: Daigo Yoshiaki , Ishiguro Akio , Ishii Shigeaki , Moriyama Yoshikazu , Suzuki Kunihiko , Yajima Masayoshi
Published: July 2019

N-type 4H-SiC homo-epitaxial films were grown by high speed wafer rotation vertical CVD tool, and both short term repeatability and long term repeatability of epitaxial growth were investigated. In the short term repeatability investigated by 6 epitaxial wafers chosen from successively grown 12 epitaxial wafers using same recipe, it was found that total variation of thickness and carrier concentration for all measurement points of 6 wafers is 1.44 and 4.64 % respectively, which indicates excellent repeatability as well as high uniform thickness and carrier concentration. In the long term repeatability investigated by a very large number of growth experiments, probability achieving target uniformity of thickness and carrier concentration of the SiC films was increased up to 1.32 times by optimizing gas nozzle structure in gas inlet compared with in the case of conventional gas nozzles. Moreover, adjustment range of C/Si ratio necessary to achieve target uniformity of thickness and carrier concentration of the films was considerably reduced to 22 % by optimized gas nozzles.
Influence of Substrate Properties on the Defectivity and Minority Carrier Lifetime in 4H-SiC Homoepitaxial Layers
Authors: Kallinger Birgit , Erlekampf Jürgen , Rosshirt Katharina , Berwian Patrick , Stockmeier Matthias , Vogel Michael , Hens Philip , Wischmeyer Frank
Published: July 2019

Two fully loaded epitaxial growth runs with 16 wafers in total were conducted in the AIXTRON G5 WW reactor in order to keep epigrowth conditions constant. The wafers were selected with a large spread of specific resistivity and dislocation densities. The resulting epilayers showed very good intra-wafer homogeneities as well as excellent wafer-to-wafer and run-to-run reproducibility with regard to epilayer thickness and doping concentration, point defect concentrations of Z1/2 and EH6/7 and the resulting Shockley-Read-Hall carrier lifetime. We found that the dislocation densities of the underlying substrates are influencing the stacking fault densities of the epilayers, which then vary between 0.1 and 10 cm-2. A substrate effect on the effective minority carrier lifetime was found.
Structural Strain in Single Layer Graphene Fabricated on SiC
Authors: Yu Wan Cheng , Chen Xiu Fang , Hu Xiao Bo , Xu Xian Gang , Jin Peng , Yu Peng , Wang Rui Qi
Published: July 2019

Single layer graphene is fabricated on the Si face of silicon carbide through thermal decomposition. The thickness of graphene was checked by a combination of ex situ Kelvin probe force microscopy together with Raman spectroscopy and atomic force microscopy. The amount of residual strain induced is calculated to between 1.3% and 0.7%. Results also show that the magnitude of strain increased with growth time while the uniformity of strain improved.
Theory of Carbon-Vacancy Diffusion at the SiO2/4H-SiC Interface
Authors: Alsnani Hind , Goss J.P. , Briddon Patrick R. , Rayson Mark J. , Horsfall Alton B.
Published: July 2019

Experimental data indicate that carbon vacancies incorporated in active regions of SiC devices are important electrical defects, responsible for device limiting effects such as carrier lifetime reduction. For field-effect transistors that include a 4H-SiC/SiO2 interface, such as at the gate, the oxidation pro- cess is understood to introduce native defects to the SiC, including injection of carbon self-interstitials and vacancies, that diffuse into the active layer and interact with other defects and impurities. It is therefore important to understand the migration behaviour of primary native defects such as VC in the vicinity of 4H-SiC/SiO2 interfaces. We report here the results of a density-functional theory investi- gation into the diffusion of the carbon vacancy in such a region. We conclude that the migration of VC is significantly hindered in the immediate vicinity of the interface, with the energy of diffusion barrier being approximately 15% greater than the corresponding diffusion in bulk 4H-SiC.
Observation of Dislocation Conversion in 4H-SiC Epitaxial Wafer by Mirror Projection Electron Microscopy
Authors: Isshiki Toshiyuki , Sato Takahiro , Hasegawa Masaki , Ohira Kentaro , Kobayashi Kenji , Miyaki Atsushi , Onuki Katsunori
Published: July 2019

Dislocations and stacking faults in 4H-SiC (0001) si epitaxial wafer was inspected by mirror projection electron microscopy (MPJ) with the aid of low-energy SEM and FIB-STEM. MPJ observation found dislocation conversion near the wafer surface, and the conversion was confirmed by micro etch pit and low energy SEM method. Another conversion occurred in the epitaxial layer on array of TED half loops, which were detected by MPJ, was also observed by cross-sectional STEM.
Terahertz Emission from SiC Natural Superlattices in Strong Electrical Field
Authors: Sankin Vladimir Ilich , Petrov Alexey G. , Nagalyuk Sergey , Shkrebiy Pavel P. , Kalinina Evgenia V. , Lebedev Alexander A.
Published: July 2019

Terahertz electroluminescence of unipolar n⁺⁺-n⁻-n⁺ SiC structures at helium temperatures and I-V characteristics of bipolar n⁺⁺-π-n⁺ SiC structures with natural superlattices at 300~K at strong electrical fields are studied. The properties of the THz electroluminescence and I-V characteristics testify that these phenomena due to Bloch oscillations.
Channeling in 4H-SiC from an Application Point of View
Authors: Pichler Peter , Sledziewski Tomasz , Häublein Volker , Bauer Anton J. , Erlbacher Tobias
Published: July 2019

During ion implantation into monocrystalline semiconductors, some of the implanted atoms will be deflected to crystal directions along which they may penetrate deeply into the crystal. We investigate such channeling effects for Al and N implantation into 4H-SiC by Monte Carlo simulations. The focus of the work is on the effects of channeling on doping profiles, the relevance for the net doping of typical power electronic devices, and the influence of scattering oxides.
1300°C Annealing of 1×1020 Al+ Ion Implanted 3C-SiC
Authors: Nipoti Roberta , Canino Maria Concetta , Bonafe Filippo , Torregrosa Frank , Monnoye Sylvain , Mank Hugues , Zielinski Marcin
Published: July 2019

The results of the first experiments for achieving the thermal equilibrium during 1300 °C annealing of 1×1020 cm-3 ion implanted Al+ in 3C-SiC are shown. X-ray diffraction, through reciprocal space maps and 2Θ scans, characterizes the 3C-SiC lattice recovery. The achievement of a ohmic behavior of Ni/Al/Ti alloy indicates the onset of a measurable electrical activation of the Al implanted layer. The Al electrical activation is qualified through the implanted layer sheet resistance.
Determination of Compensation Ratios of Al-Implanted 4H-SiC by TCAD Modelling of TLM Measurements
Authors: Kocher Matthias , Yao B.T. , Weisse Julietta , Rommel Mathias , Xu Zong Wei , Erlbacher Tobias , Bauer Anton J.
Published: July 2019

The prediction of the compensation induced hole concentration reduction in implanted Al regions is a key parameter in developing high power SiC devices. Hall effect measurements are commonly used to determine the compensation ratio of Al implanted regions. Due to the fact that this measurement method is rather complex, an approximate method was developed by using transfer length method structure measurements in combination with a TCAD simulation model. The determined compensation ratios from this work’s simulation and from Hall effect measurements from literature show consistent compensation ratios. Based on this data a fit function was derived which allows for estimating the compensation ratio for a wide Al concentration range.
Characterization of Ba-Introduced Thin Gate Oxide on 4H-SiC
Authors: Muraoka Kosuke , Ishikawa Seiji , Sezaki Hiroshi , Maeda Tomonori , Kuroki Shin Ichiro
Published: July 2019

A thickness of Ba-introduced gate oxide was controlled with the oxygen concentration and a barrier layer thickness at a post-deposition annealing. The oxidation rate becomes slower with the low oxygen concentration and the thick barrier layer, and the thin oxide of 12 nm was realized with O2 5% and 9 nm of the barrier layer. This Ba-introduced thin gate oxide resulted in the field effect mobility of 13 cm2/Vs and the interface state density of 2×1011 cm-2eV-1 at 0.25 eV below the conduction band edge of 4H-SiC.
Study of the Post-Oxidation-Annealing (POA) Process on Deposited High-Temperature Oxide (HTO) Layers as Gate Dielectric in SiC MOSFET
Authors: Severino Andrea , Piluso Nicolo , di Stefano Maria Ausilia , Cordiano Francesco , Camalleri Marco , Arena Giuseppe
Published: July 2019

In the development of SiC MOSFETs, further improvements are ongoing to improve device performances. One of the critical part at the device level is the gate oxide/semiconductor interface, being the gate oxide a standard SiO2 layer. This work is focused on the investigation of the effect of post oxidation annealing process (POA) carried out after the deposition of high-temperature oxide (HTO) layer used for dielectric gate formation by using NO and N2O gasses. The variation of Dit by applying the POA in N2O is considerable with respect to the as-deposited oxide layer as the density is reduced of about two order of magnitude. A further reduction of interface trap density from 2.3×1010 to 8.5×109 traps/cm2 has been observed when NO POA process was applied. Full vertical power MOSFETs were also analyzed in order to measure the channel mobility of the device. Channel mobility has been seen to raise its value from 45 cm2/Vs to a value of about 62 cm2/Vs when NO-based POA process was performed. NO-based POA process results in a much more effective interface at device level.
Electrical Properties of Thermal Oxide on 3C-SiC Layers Grown on Silicon
Authors: Fiorenza Patrick , Greco Giuseppe , Di Franco Salvatore , Giannazzo Filippo , Monnoye Sylvain , Zielinski Marcin , La Via Francesco , Roccaforte Fabrizio
Published: July 2019

In this paper, the electrical properties of a thermal oxide (SiO2) grown onto 3C-SiC layers on silicon were investigated, by monitoring the behavior of MOS capacitors. In particular, the growth rate of thermal SiO2 was dependent on the different surface roughness condition. However, independent of the roughness a high density of positive charge was detected. The sample having the smooth surface (subjected to CMP) showed a notably improved dielectric breakdown (BD) field. However, the best BD on macroscopic MOS capacitors was still far from the ideal behavior. Additional insights could be gained employing a nanoscale characterization that revealed the detrimental role of persisting extended defects in the semiconductor. In the semiconductor region far from extended defects the nanoscale BD kinetics was nearly ideal.
Fabrication and Characterization of Ohmic Contacts to 3C-SiC Layers Grown on Silicon
Authors: Spera Monia , Greco Giuseppe , Lo Nigro Raffaella , Di Franco Salvatore , Corso Domenico , Fiorenza Patrick , Giannazzo Filippo , Zielinski Marcin , La Via Francesco , Roccaforte Fabrizio
Published: July 2019

This paper reports on the formation and characterization of Ohmic contacts to n-type and p-type type 3C-SiC layers grown on silicon substrates. In particular, Ohmic contact behavior was obtained either using Ni or Ti/Al/Ni layers annealed at 950°C. The values of the specific contact resistance ρc estimated by means of circular TLM (C-TLM) structures varied in the range ~ 10-3-10-5 Ωcm2, depending on the doping level of the 3C-SiC layer. A structural analysis performed by X-Ray Diffraction (XRD) allowed to identify the main phases formed upon annealing, i.e., Ni2Si and Al3Ni2. The morphology of the reacted contacts depended on that of the underlying substrate. The results can be useful for the development of a variety of devices on the cubic 3C-SiC polytype.
Study of 4H-SiC Superjunction Schottky Rectifiers with Implanted P-Pillars
Authors: Baker G.W.C. , Chan Chun W. , Dai Tian Xiang , Renz A. Benjamin , Li Fan , Shah Vishal Ajit , Mawby Philip  Andrew , Gammon Peter Michael
Published: July 2019

This paper discusses the study of 4H Silicon Carbide (4H-SiC) Schottky rectifier structures based on the superjunction (SJ) principle. The effects of device geometry have been investigated to optimise the trade-off between breakdown voltage (VBD), specific on-resistance (RON,SP), and the ion-implantation fabrication window, so ensuring the final design is practically realisable. In this study, both full-SJ and semi-SJ (SSJ) layouts improve the VBD-RON,SP trade-off to below the 4H-SiC unipolar limit. In comparison to a conventional planar Schottky diode, full SJ structures, with p-pillars that traverse the full length of the n-drift region, have a 7x improvement in RON,SP for a 50-100 V reduction in VBD. In comparison, the SSJ structure is composed with the combination of the SJ structure and an n-bottom assist layer (BAL), which adds 2-μm of n-drift below the SJ pillars. The SSJ structure demonstrates a 5x improvement in RON,SP for a 300 V increase in VBD, for the same aspect ratio. Most favourably, the SSJ structure also has an ion-implantation processing window 60% higher than the full SJ device, offering better anti-charge-imbalance characteristics. In both full and semi layouts, a trench sidewall angled (α) at 80o was considered optimal, resulting in a slightly higher VBD and RON,SP, and a wider processing window, compared to vertical (90o) sidewalls.
Comparison of SiC MOSFET Characteristics Following Body-Diode Forward-Current Stress
Authors: Green Ronald , Lelis Aivars J. , Nouketcha Franklin L.
Published: July 2019

The effect of forward-current stress of the body diode on the operating characteristics of various commercially-available SiC power MOSFETs was compared. The one set of recent-vintage second-generation 1200-V devices studied showed no degradation at all when the body diode was forward conducted—either in the body diode or the MOSFET characteristics. This is a distinct improvement from first generation 1200-V devices from various suppliers. This degradation phenomenon was consistent with the formation of stacking faults during current stress, which typically reduced MOSFET conductivity, and in some devices increased the Off-state leakage current. Although first-generation 1700-V MOSFET characteristics showed no degradation of the body diode, they did experience a degradation of the blocking voltage due to charge trapping during the stress.
Inverse Modeling of 4H-SiC Trench Gate MOSFETs Validated with Electrical and Physical Characterization
Authors: Sakai Atsushi , Eikyu Katsumi , Hisada Kenichi , Yamashita Yasuhiro , Arai Koichi , Arie Hiroyuki , Akiyama Yutaka , Yamashita Tomohiro
Published: July 2019

The effective modeling methodology of 4H-SiC trench gate MOSFETs is presented. The potential barrier lowering at the MOS channel region suggested by I-V measurements is implemented to commercial TCAD tool as the net-doping reduction. The proposed model is validated by comparison of TCAD simulations with I-V measurements and SEM image observations.