6,591 research outputs found

    Does higher education foster critical and creative learners? An exploration of two universities in South Korea and the USA

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    This paper describes two studies that explore students' beliefs about critical and creative learning at two universities, and considers the implications of those beliefs in comparison to the universities' stated education goals. One is a mixed method study of students at a top university in Korea, and the second is a comparative study between the Korean university and a United States (US) university. The first study found that both high-achievers and the general population at a top Korean university perceived their critical and creative abilities as lower than their receptive learning abilities, and that higher achievers were neither more critical nor creative than lower achievers. The second study finds that the Korean university students, compared to US students, were more likely to rate their receptive learning ability as higher than their critical and creative learning abilities. Comparisons across year of higher education (HE) suggest that Korean students' perceptions did not significantly change with respect to year in school, while US students' perceptions of critical learning abilities significantly increased across school years. Results are discussed with respect to the impact of culture, epistemological beliefs, and HE instruction on critical and creative learning

    Radial distribution of RNA genome packaged inside spherical viruses

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    The problem of RNA genomes packaged inside spherical viruses is studied. The viral capsid is modeled as a hollowed sphere. The attraction between RNA molecules and the inner viral capsid is assumed to be non-specific and occurs at the inner capsid surface only. For small capsid attraction, it is found that monomer concentration of RNA molecules is maximum at the center of the capsid to maximize their configurational entropy. For stronger capsid attraction, RNA concentration peaks at some distance near the capsid. In the latter case, the competition between the branching of RNA secondary struture and its adsorption to the inner capsid results in the formation of a dense layer of RNA near capsid surface. The layer thickness is a slowly varying (logarithmic) function of the capsid inner radius. Consequently, for immediate strength of RNA-capsid interaction, the amount of RNA packaged inside a virus is proportional to the capsid {\em area} (or the number of proteins) instead of its volume. The numerical profiles describe reasonably well the experimentally observed RNA nucleotide concentration profiles of various viruses.Comment: 5 pages, 2 figures. Abstract, introduction rewritten. Comparison to actual virus profiles added. Submitted to PR

    Investigating Information Structure of Phishing Emails Based on Persuasive Communication Perspective

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    Current approaches of phishing filters depend on classifying messages based on textually discernable features such as IP-based URLs or domain names as those features that can be easily extracted from a given phishing message. However, in the same sense, those easily perceptible features can be easily manipulated by sophisticated phishers. Therefore, it is important that universal patterns of phishing messages should be identified for feature extraction to serve as a basis for text classification. In this paper, we demonstrate that user perception regarding phishing message can be identified in central and peripheral routes of information processing. We also present a method of formulating quantitative model that can represent persuasive information structure in phishing messages. This paper makes contribution to phishing classification research by presenting the idea of universal information structure in terms of persuasive communication theories

    Exploring Satisfaction with and Trust in Social Networking Sites through the Lens of Fan Pages: Uncertainty Reduction and General Systems Theory Perspective

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    The purpose of this study is to examine social networking sites (SNS) users’ overall satisfaction with and trust in SNS, as related to their activities of visiting fan pages. We employ two theories—uncertainty reduction theory (URT) and general systems theory (GST)—to examine antecedents affecting overall satisfaction with and trust in SNS. Using a web-based survey, we analyzed 200 SNS users who follow at least one company’s fan page, and utilized seemingly unrelated regression (SUR) models to empirically test our hypotheses. Our findings indicate that uncertainty reduction strategies supported by URT are significantly associated with perceived usefulness of companies’ posts in their fan pages. In turn, perceived usefulness of those posts promotes more visits to the fan page. Finally, users’ perceived usefulness of fan page posts eventually accounts for the overall satisfaction with and trust in SNS. The implications and limitations are discussed at the end of this study

    Curriculum integration for dental education : A lesson learned from real experiences of development and implementation

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    This paper presents a dental school's experience of curriculum development and the process of implementation. It includes the things that can be expected to happen or that may go beyond expectations in the development of new curriculum for the College of Dentistry (School of Dentistry), Seoul National University. In 2002, the Ministry of Education and Human Resources Development of Korea announced Introduction of new school system in which provides medical and dental education after bachelor's degree. This "Professional Graduate School" system is one of the greatest challenges for Korean dental education. Now Korean dental schools chose two different dental education systems from 2005, the six year dental college system and the four year professional dental graduate school system. College of Dentistry, Seol National University chose the new system. The school also changed curriculum. The change of dental education system is one, but not all of the reason for the curriculum reform. Through the sophisticated process of problem identification and needs assessments, we chose the integrated curriculum. A careful planning and organization process were applied. The whole process of curriculum development took ten month. The evaluation is still going on. Even the curriculum intended to apply the solid principles and aims towards sound objectives; the curriculum evaluationin the present is not very encouraging. It casts lots of pending questions. Promising part of the new curriculum has the flexibility and readiness to change of environment

    Significado diagenético de las composiciones isotópicas de carbono, oxígeno y estroncio en la Formación Mural (Aptiense-Albiense, zona Cerro Pimas, norte de Sonora, México)

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    A carbon, oxygen and strontium isotopic study on the predominantly carbonate succession of the shallow marine Mural Formation in the Cerro Pimas locality of northern Sonora (Mexico) was undertaken to understand isotopic variations in seawater during Aptian- Albian time. Petrographic study has been carried out on these limestones to support the isotopic study. The limestones show low content of TOC, both negative and positive δ13C values (-4.1 to +2.2‰ VPDB) and d18O values varying from -13.4 to -8.9‰ VPDB. The carbon isotope composition, δ13C vs δ18O plot and Mn/Sr ratio suggest that the δ13C measured values are primary in nature and remain unaltered during diagenesis. The carbon isotope curve shows a positive δ13C excursion followed by a negative event in the lower part of the Los Coyotes Member (Lower Albian) of the Mural Formation and confirm the global nature of the episode OAE 1b in the Cerro Pimas section. The 87Sr/86Sr ratios for limestones of the Mural Formation (0.707221 to 0.707340) are similar to the ratios for Late Aptian and Early Albian seawater (0.70726 to 0.70740). In addition, 87Sr/86Sr age of the Cerro La Ceja member (113.4 Ma; Late Aptian age) is comparable to that of published zircon radiometric age. The numerical age of Los Coyotes (112.0 Ma and 111.1 Ma) and Cerro La Espina (110.9 Ma and 110.7 Ma) members indicate also Early Albian age. The whole-rock Sr isotope ages in this study are consistent with the previously published radiometric and biostratigraphic ages.En este trabajo se presenta un estudio isotópico de carbón, oxígeno y estroncio de la sucesión predominantemente carbonatada de la Formación Mural que aflora en la localidad de Cerro Pimas, norte de Sonora (México) con el fin de entender las variaciones isotópicas del agua de mar dentro de la cual se depositó esta unidad durante el Aptiense-Albiense. Los datos isotópicos están apoyados por un estudio petrográfico de las rocas carbonatadas. Las calizas tienen un contenido bajo de carbón orgánico total, valores negativos y positivos de δ13C (-4.1 a +2.2‰ VPDB) y valores de d18O entre -13.4 y -8.9 ‰. La composición de los isótopos de carbón, la relación δ13C vs δ18O y la proporción Mn/Sr sugieren que los valores medidos de δ13C son de naturaleza primaria y no fueron alterados durante la diagénesis. La curva de isótopos de carbón presenta una excursión positiva de δ13C seguida por un evento negativo en la parte inferior del Miembro Los Coyotes (Albiense inferior) de la Formación Mural y confirma la presencia del episodio global OAE 1b en la sección estudiada de Cerro Pimas. La relación 87Sr/86Sr de las calizas de la Formación Mural (0.707221 a 0.707340) es similar a la relación isotópica del agua de mar del Aptiense tardío y Albiense temprano (0.70726 a 0.70740). Además, una edad 87Sr/86Sr de 113.4 Ma (Aptiense tardío) que hemos obtenido para el Miembro Cerro La Ceja es similar a una edad radiométrica U-Pb en circones previamente publicada. Del mismo modo, hemos obtenido edades 87Sr/86Sr en roca total para los Miembros Los Coyotes (112.0 Ma and 111.1 Ma) y Cerro La Espina (110.9 Ma and 110.7 Ma) que confirman una edad Albiense temprano que es consistente con edades radiométricas y bioestratigráficas previamente reportadas

    Mass inflation in f(R) gravity: A conjecture on the resolution of the mass inflation singularity

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    We study gravitational collapse of a charged black hole in f(R) gravity using double-null formalism. We require cosmological stability to f(R) models; we used the Starobinsky model and the R + (1/2)cR^2 model. Charged black holes in f(R) gravity can have a new type of singularity due to higher curvature corrections, the so-called f(R)-induced singularity, although it is highly model-dependent. As the advanced time increases, the internal structure will approach the Cauchy horizon, which may not be an inner apparent horizon. There is mass inflation as one approaches the Cauchy horizon and hence the Cauchy horizon may be a curvature singularity with nonzero area. However, the Ricci scalar is finite for an out-going null observer. This can be integrated as follows: Cosmologically stable higher curvature corrections of the Ricci scalar made it bounded even in the presence of mass inflation. Finally, we conjecture that if there is a general action including general higher curvature corrections with cosmological stability, then the corrections can make all curvature components finite even in the presence of mass inflation. This might help us to resolve the problem of inner horizon instability of regular black hole models.Comment: 31 pages, 15 figure

    Structures of Staphylococcus aureus peptide deformylase in complex with two classes of new inhibitors

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    Peptide deformylase (PDF) catalyzes the removal of the formyl group from the N-terminal methionine residue in newly synthesized polypeptides, which is an essential process in bacteria. Four new inhibitors of PDF that belong to two different classes, hydroxamate/pseudopeptide compounds [PMT387 (7a) and PMT497] and reverse-hydroxamate/nonpeptide compounds [PMT1039 (15e) and PMT1067], have been developed. These compounds inhibited the growth of several pathogens involved in respiratory-tract infections, such as Streptococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenzae, and leading nosocomial pathogens such as Staphylococcus aureus and Klebsiella pneumoniae with a minimum inhibitory concentration (MIC) in the range 0.1-0.8 mg ml(-1). Interestingly, the reverse-hydroxamate/nonpeptide compounds showed a 250-fold higher antimicrobial activity towards S. aureus, although the four compounds showed similar K-i values against S. aureus PDF enzymes, with Ki values in the 11-85 nM range. To provide a structural basis for the discovery of additional PDF inhibitors, the crystal structures of S. aureus PDF in complex with the four inhibitors were determined at resolutions of 1.90-2.30 angstrom. The inhibitor-bound structures displayed distinct deviations depending on the inhibitor class. The distance between the Zn2+ ion and the carbonyl O atom of the hydroxamate inhibitors (or the hydroxyl O atom of the reverse-hydroxamate inhibitors) appears to be correlated to S. aureus inhibition activity. The structural information reported in this study should aid in the discovery of new PDF inhibitors that can be used as novel antibacterial drugs
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