1,346 research outputs found
HYDROGEN BONDING IN -NITRO ALCOHOLS. III. PYRIDINE COMPLEXES
BETA -Nitro alcohols form stable 1:1 complexes with pyridine, examples of which were prepared. In solvents such as dichloromethane and carbon tetrachloride the complexes partially dissociate into their components. The dissociation constants for the equilibria were determined by infrared methods and may be used as a measure of the strength of the complex hydrogen bond. The dissociation constants decrease with increasing number of BETA -nitro groups. Some reactions of the pyridine complexes are described. (auth
Moving beyond methodising theory in preparing for the profession
For those preparing for outdoor education and related professions, formal theory has an important role to play in terms of informing professional practice and understandings of teaching-learning dynamics. Despite this, surprisingly little is understood about how pre-service outdoor educators (POEs) view and engage with it in their preparation courses. Drawing on findings of a case study in an Australian outdoor education teacher education (OETE) course, this article explores POE theory engagement focussing on a problematic tendency to methodise formal theory, that is, to treat theories as formula for action. The authors argue that this tendency is concerning because it ignores the complexity and problematic nature of both theory-practice relationships and outdoor education pedagogy. The discussion highlights contributing factors and implications for OETE, especially with respect to enabling aspiring outdoor educators in tertiary courses to move beyond methodising theory as they enter the outdoor profession
In vivo tumor growth of high-grade serous ovarian cancer cell lines
OBJECTIVE:
Genomic studies of ovarian cancer (OC) cell lines frequently used in research revealed that these cells do not fully represent high-grade serous ovarian cancer (HGSOC), the most common OC histologic type. However, OC lines that appear to genomically resemble HGSOC have not been extensively used and their growth characteristics in murine xenografts are essentially unknown.
METHODS:
To better understand growth patterns and characteristics of HGSOC cell lines in vivo, CAOV3, COV362, KURAMOCHI, NIH-OVCAR3, OVCAR4, OVCAR5, OVCAR8, OVSAHO, OVKATE, SNU119 and UWB1.289 cells were assessed for tumor formation in nude mice. Cells were injected intraperitoneally (i.p.) or subcutaneously (s.c.) in female athymic nude mice and allowed to grow (maximum of 90 days) and tumor formation was analyzed. All tumors were sectioned and assessed using H&E staining and immunohistochemistry for p53, PAX8 and WT1 expression.
RESULTS:
Six lines (OVCAR3, OVCAR4, OVCAR5, OVCAR8, CAOV3, and OVSAHO) formed i.p xenografts with HGSOC histology. OVKATE and COV362 formed s.c. tumors only. Rapid tumor formation was observed for OVCAR3, OVCAR5 and OVCAR8, but only OVCAR8 reliably formed ascites. Tumors derived from OVCAR3, OVCAR4, and OVKATE displayed papillary features. Of the 11 lines examined, three (Kuramochi, SNU119 and UWB1.289) were non-tumorigenic.
CONCLUSIONS:
Our findings help further define which HGSOC cell models reliably generate tumors and/or ascites, critical information for preclinical drug development, validating in vitro findings, imaging and prevention studies by the OC research community
CEO Education and the Ability to Raise Capital
Research Question/Issue: Using a unique handâcollected dataset, this study examines the role of Chief Executive Officer (CEO) educational attainments in relation to newly public firms.
Research Findings/Insights: We find that Initial Public Offering (IPO) firms led by CEOs with superior educational credentials â in terms of level and quality â are associated with lower levels of IPO underpricing. This association is mainly driven by CEOs that hold advanced degrees. Notably, a differenceâinâdifference approach based on two quasiânatural experiments indicates that the impact of CEO education on IPO underpricing is more pronounced within environments characterized by lower information transparency. The baseline results also hold in the longer term, thereby confirming the value of signaling prestigious academic awards at the time of the IPO.
Theoretical/Academic Implications: Using human capital, institutional and upper echelon theories, we hypothesize and demonstrate that CEO educational attainments do not unambiguously affect investorsâ perceptions of a firm's future prospects. Instead, their influence depends on the quality of CEO education as well as on the degree of uncertainty regarding the firm's future performance, and the level of information asymmetry between issuers and prospective investors. To our knowledge, this is the first study that provides a comprehensive treatment of the role of CEO education in the IPO context.
Practitioner/Policy Implications: Our evidence on the importance of CEO education, and especially that CEOs with varying levels and quality of educational training might differentially affect newly listed firms, is useful to providers of financial capital and boards of directors interested in assessing the viability of new ventures. The implication of our study for IPO investors is that it is worth paying more to take an equity position in firms run by betterâeducated CEOs
EmissĂ”es pĂșblicas de açÔes, volatilidade e insider information na Bovespa
O trabalho utiliza um estudo de evento para
examinar os retornos de açÔes relacionados a emissĂ”es pĂșblicas por empresas brasileiras listadas na BOVESPA, realizadas entre 1992 e 2002, buscando
determinar como o mercado reagiu antes, durante e
depois da data do anĂșncio da emissĂŁo. ApĂłs utilizar a metodologia convencional de mensuração de retornos
anormais por OLS, foram utilizados modelos
ARCH e GARCH, que levam em consideração a heteroscedasticidade
condicional da volatilidade dos
retornos anormais, em mais de 70% da amostra,
após a constatação da presença desses processos
nos resĂduos originais. Os resultados mostram que
1) hĂĄ evidĂȘncias de insider information antes da data do anĂșncio, (2) que ocorrem retornos anormais
negativos na data do anĂșncio e (3) que, no perĂodo
de um ano após as emissÔes, as açÔes das empresas
que captaram recursos via underwriting tiveram
retornos negativos apĂłs ajuste ao risco e ao mercado
The use of learner-generated drawings in the development of music studentsâ teacher identities
Identity development is a continuous process framed within changing social contexts, and is particularly problematic for musicians and other artists whose work contradicts the mythologized image of the artist. The purpose of this article is to examine the professional growth of music students in relation to developing teacher identities. The article reports on the use of learner-generated drawings and journal reflections produced by music performance and education majors; in particular, the article probes studentsâ perceptions of teaching within a traditional career hierarchy that favours performance and artistic creation above all else. Whilst initial student drawings illustrated traditional images of the teacher as knowledge giver, these gave way to student-centred images in which students appeared to identify with teaching in new ways. The combination of textual and non-textual data provided insights that would not otherwise have been evident, and the consideration of âpossible selvesâ became a useful tool in the explorations of identity and career
Investigation of chemistry graduate teaching assistantsâ teacher knowledge and teacher identity
Graduate students play an integral role in undergraduate chemistry education at doctoral granting institutions where they routinely serve as instructors of laboratories and supplementary discussion sessions. Simultaneously, graduate teaching assistants (GTAs) balance major research and academic responsibilities. Although GTAs have substantial instructional facetime with large numbers of undergraduate students, little is known about their conceptions of teaching or their identities as teachers. To investigate the knowledge that GTAs have regarding teaching in this unique context, their teaching identities, and how these developed, we conducted 22 interviews with graduate students from several universities at various levels in their graduate school career using a modified Teacher Beliefs Interview. Interviews were analyzed for two overarching teacher learning constructs: teacher knowledge and teacher identity. We characterized chemistry GTAsâ teacher knowledge and identity and determined major influencing factors. We found that chemistry GTAs often identified as a tutor or lab manager, which hindered their selfâinvestment in developing as teachers. The results presented herein contribute to an understanding of GTAsâ teacher knowledge, teacher identity, and their teaching context, from which training can be designed to best support GTA development.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155950/1/tea21618_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155950/2/tea21618.pd
El Conocimiento DidĂĄctico del Contenido en ciencias: estado de la cuestiĂłn
This paper gives a descriptive overview of the literature related to Pedagogical Content Knowledge - PCK - in the sciences. It is expected that this review can contribute to a better understanding of PCK, pointing out what has been investigated about this concept. Specifically, we analyze: a) how PCK is defined, what are its main features and how it has been appropriated by teachers; b) the relationship between PCK, knowledge of the contents to be taught and students learning; c) how PCK was actually used in teachers' training and teachers' evaluation; and, d) the scientific areas in which PCK has been studied. It concludes that PCK is an essential tool for improving the quality of teacher training
PERENCANAAN FDD-LTE MENGGUNAKAN FREKUENSI 1800MHZ PADA PERANCANGAN INDOOR BUILDING COVERAGE DI YOGYA KEPATIHAN BANDUNG
Material sebuah gedung merupakan salah satu penyebab dari terjadinya fading sehingga menghambat sinyal masuk ke dalam gedung yang mengakibatkan sinyal didalam gedung tersebut lemah. Pada gedung Yogya Kepatihan memiliki masalah terhadap kualitas jaringan didalamnya sehingga butuh dilakukannya perencanaan Indoor untuk mengatasi masalah tersebut. Berdasarkan hasil analisis dilakukannya walk test diperoleh nilai rata-rata dari RSRP sebesar -96 dBm dan SINR sebesar 8 dB, sedangkan drivetest sekitaran Gedung memperoleh hasil RSRP sebesar -72 dBm dan SINR sebesar 5 dB.
Penerapan Indoor Building Coverage (IBC) ini menggunakan sistem Distributed Antenna System (DAS) dengan teknik FDD-LTE pita frekuensi 1800 MHz, untuk simulasinya menggunakan Radiowave Propagation Software (RPS) dengan model propagasi Cost-231 Multi-Wall Indoor. Operator Telkomsel menjadi kasus dalam penerapan ini. Walktest di dalam gedung menggunakan Nemo handy, sedangkan drivetest menggunakan GnetTrack Pro. Setelah mendapatkan data lalu dilanjutkan perhitungan capacity planning dan coverage planning sehingga mendapatkan perhitungan untuk jumlah antena yang akan di simulasikan ke dalam software RPS untuk mendapatkan hasil parameter yang sesuai dengan standar Key Performance Indicator (KPI) Operator Telkomsel yaitu RSRP > -85 dBm dan SINR > 10 dB.
Dari hasil simulasi ini, diperoleh peningkatan nilai rata-rata RSRP > -76 dBm sebanyak 81,95% dan rata-rata nilai SINR > 26 sebanyak 71,56%.
Kata Kunci: LTE, FDD, IBC, DAS, RPS
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