bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Relationship Between Team Discourse, Self‐Efficacy, and Individual Achievement: A Sequential Mixed‐Methods Study
Authors: Purzer ŞEnay 
Published: January 2013

BackgroundWhile much research has been conducted to study the effect of teaming on student learning and attitudes, few studies have explored the nature of team discourse and how these discussions support or hinder student learning and self‐efficacy.Purpose (Hypothesis)This study investigated the relationship between verbal exchanges, self‐efficacy, and individual student achievement. Results are discussed through the lenses of two frameworks: Bandura's social cognitive theory and Vygotsky's social constructivist theory.Design/MscethodTwenty‐two first‐year engineering students participated in this study. The verbal exchanges of these students were recorded and then coded into 35 discourse moves and six discourse actions. Data on students’ pre and post self‐efficacy were also collected. Correlations between discourse actions, self‐efficacy scores, and individual student achievement were computed.ResultsStudents engaged in six types of discourse actions: task‐oriented, response‐oriented, learning‐oriented, support‐oriented, challenge‐oriented, and disruptive. Results indicated no direct correlation between support‐oriented discourse (verbal persuasions) and achievement. However, there was a moderate positive correlation between post self‐efficacy and the extent to which a student engaged in support‐oriented discourse. Engaging in challenge‐oriented or learning‐oriented discourse did not reveal correlations with self‐efficacy or achievement.ConclusionsFinding that self‐efficacy and achievement are related confirms Bandura's self‐efficacy theory. Furthermore, the low self‐efficacy of under‐performers was evident in their grades, as well as in the conversations of team members. However, contrary to theory, supportive comments (verbal persuasions) received were not correlated with self‐efficacy. The scarcity of challenge‐oriented discourse (argumentation) is a concern and should be addressed in future research.
Self‐Efficacy for Cross‐Disciplinary Learning in Project‐Based Teams
Authors: Schaffer Scott P. , Chen Xiaojun , Zhu Xiumei , Oakes William C. 
Published: January 2013

BackgroundWhile research indicates that self‐efficacy is related to learning on discrete tasks, less is known about self‐efficacy for learning in complex, ill‐structured learning environments. A measure of self‐efficacy for design teams provides grounding for the design of learning support.Purpose (Hypothesis)This study aims to determine the usefulness of a measure of self‐efficacy for cross‐disciplinary team learning (CDTL) within a multi‐disciplinary, project based setting. Research questions include: (1) Does student efficacy for CDTL change over the course of the semester? (2) What is the effect of (a) task complexity; (b) prior learner experience; (c) team composition; and (d) personal factors on efficacy for CDTL?Design/MethodEfficacy for CDTL while working on multi‐disciplinary team projects was assessed using a 16‐item Selfefficacy for CDTL scale. A total of 112 undergraduates from 34 teams in a service learning program completed both pre and post project questionnaires.ResultsA statistically significant increase in pre‐post semester self‐efficacy was found across three team learning factors: identification, recognition, and integration. Individual GPA and year in college were related to higher levels of improvement in the identification factor, while the completion of multiple design phases in team tasks was related to lower levels of improvement in the identification factor.ConclusionsThis study contributes to our knowledge of individual self‐efficacy and the design of learning environments involving multi‐disciplinary teams. It is an important step toward the development of theory and evidence that can help higher educational institutions to better understand if and how students learn to collaborate while working on team design projects.
Development of the Heat and Energy Concept Inventory: Preliminary Results on the Prevalence and Persistence of Engineering Students' Misconceptions
Authors: Prince Michael , Vigeant Margot , Nottis Katharyn 
Published: January 2013

BackgroundStudents frequently hold a number of misconceptions related to temperature, heat and energy. There is not currently a concept inventory with sufficiently high internal reliability to assess these concept areas for research purposes. Consequently, there is little data on the prevalence of these misconceptions amongst undergraduate engineering students.Purpose (Hypothesis)This work presents the Heat and Energy Concept Inventory (HECI) to assess prevalent misconceptions related to: (1) Temperature vs. Energy, (2) Temperature vs. Perceptions of Hot and Cold, (3) Factors that affect the Rate vs. Amount of Heat Transfer and (4) Thermal Radiation. The HECI is also used to document the prevalence of misconceptions amongst undergraduate engineering students.Design/MethodItem analysis, guided by classical test theory, was used to refine individual questions on the HECI. The HECI was used in a one group, pre‐test‐post‐test design to assess the prevalence and persistence of targeted misconceptions amongst a population of undergraduate engineering students at diverse institutions.ResultsInternal consistency reliability was assessed using Kuder‐Richardson Formula 20; values were 0.85 for the entire instrument and ranged from 0.59 to 0.76 for the four subcategories of the HECI. Student performance on the HECI went from 49.2% to 54.5% after instruction. Gains on each of the individual subscales of the HECI, while generally statistically significant, were similarly modest.ConclusionsThe HECI provides sufficiently high estimates of internal consistency reliability to be used as a research tool to assess students' understanding of the targeted concepts. Use of the instrument demonstrates that student misconceptions are both prevalent and resistant to change through standard instruction.
Learning in Graduate Engineering Research Groups of Various Sizes
Authors: Crede Erin , Borrego Maura 
Published: January 2013

BackgroundEngineering graduate education, particularly at the doctoral level, relies heavily on mentored research experiences often conducted in a research group.Purpose (Hypothesis)The purpose of this study is to understand how and under what conditions research groups foster successful learning and professional development for graduate engineering students, and how these findings can be used to inform management of engineering research groups to optimize student learning, productivity, and intent to complete the degree.Design/MethodThis study utilizes a sequential exploratory mixed methods design, with nine months of ethnographically guided observations and interviews used to develop an online survey instrument. Data reported in this paper include results from the ethnographic analysis and survey responses from over 800 students at four institutions.ResultsKey findings from the ethnographic analysis indicate that group size directly influences the mechanisms of student learning. Survey results confirm the prevalence of engineering graduate research groups, as well as several elements common across research groups from different universities and academic departments, including: interactions and communication, access to resources, and role of the advisor.ConclusionsAn understanding of the mechanisms for learning in research groups can be used by engineering administrators, faculty members, and graduate students to create an environment that fosters successful learning and professional development. We also recommend practices for ensuring positive experiences for all graduate students, which may ultimately reduce attrition from engineering graduate programs.
Evidence that a transcription factor regulatory network coordinates oxidative stress response and secondary metabolism in aspergilli
Authors: Hong Sung‐Yong , Roze Ludmila V. , Wee Josephine , Linz John E. 
Published: January 2013

AbstractThe mycotoxin aflatoxin is a secondary metabolite and potent human carcinogen. We investigated one mechanism that links stress response with coordinate activation of genes involved in aflatoxin biosynthesis in Aspergillus parasiticus. Electrophoretic mobility shift assays demonstrated that AtfB, a basic leucine zipper (bZIP) transcription factor, is a master co‐regulator that binds promoters of early (fas‐1), middle (ver‐1), and late (omtA) aflatoxin biosynthetic genes as well as stress‐response genes (mycelia‐specific cat1 and mitochondria‐specific Mn sod) at cAMP response element motifs. A novel conserved motif 5′‐T/GNT/CAAG CCNNG/AA/GC/ANT/C‐3′ was identified in promoters of the aflatoxin biosynthetic and stress‐response genes. A search for transcription factors identified SrrA as a transcription factor that could bind to the motif. Moreover, we also identified a STRE motif (5′‐CCCCT‐3′) in promoters of aflatoxin biosynthetic and stress‐response genes, and competition EMSA suggested that MsnA binds to this motif. Our study for the first time provides strong evidence to suggest that at least four transcription factors (AtfB, SrrA, AP‐1, and MsnA) participate in a regulatory network that induces aflatoxin biosynthesis as part of the cellular response to oxidative stress in A. parasiticus.
One‐stage Resection for Bismuth Type IV Hilar Cholangiocarcinoma with High Hilar Resection and Parenchyma‐preserving Strategies: A Cohort Study
Authors: Tan Jing Wang , Hu Ben Shun , Chu Ya Juan , Tan Yun Chang , Ji Xu , Chen Ke , Ding Xiang Min , Zhang Aiqun , Chen Fei , Dong Jia Hong 
Published: January 2013

AbstractBackgroundBismuth type IV hilar cholangiocarcinoma (HC) tumors are usually considered unresectable. The strategies of high hilar resection while preserving liver parenchyma can achieve potentially one‐stage curative resection for this condition. The aim of the present study was to investigate the feasibility and safety of available strategies.MethodsFifty‐one consecutive patients with bismuth type IV HC who underwent one‐stage resection were retrospectively reviewed with regard to curative resection rate, remnant liver volume, morbidity, mortality, and survival time.ResultsThe total median survival time was 29 months. The R0 (curative resection) rate was 57.8 %. The ratio of the remnant liver volume (RLV) to the standard liver volume (SLV) ranged from 35.0 to 60.6 %, with a mean of 44.5 %. The in‐hospital mortality and morbidity rates were 3.9 and 37.2 %, respectively. In the R0 patients’ survival, there was not a significant difference between bilioenteric anastomosis and hepatoenteric anastomosis (P = 0.714).ConclusionsCombined caudate lobe and high hilar resection (CCHR) is technically safe and oncologically justifiable and could be adopted with a high cure rate as a one‐stage resection procedure for most patients with Bismuth type IV HC whose total bilirubin level is less than 20 mg/L and whose direct bilirubin is more than 60 % of total bilirubin.
Close Association of Metastasis‐Associated Protein 1 Overexpression with Increased Angiogenesis and Poor Survival in Patients with Histologically Node‐Negative Gastric Cancer
Authors: Deng Xiaomei , Du Lutao , Wang Chuanxin , Yang Yongmei , Li Juan , Liu Hui , Zhang Jian , Wang Lili , Zhang Xin , Li Wei , Zhang Xuhua , Wang Shun , Dong Zhaogang 
Published: January 2013

AbstractBackgroundAlthough metastasis‐associated protein 1 (MTA1) has been recently demonstrated as a potent angiogenesis‐promoting factor in various malignant tumors, its angiogenic property in gastric cancer (GC) remains unclear. This study has detected the expression of MTA1 protein in surgically resected tissues of pathologic N0 (pN0) GC and further investigated its relation with other clinicopathologic factors and tumor angiogenesis and prognosis.MethodsMTA1 protein expression was detected immunohistochemically in 111 pN0 GC specimens. Its correlations with clinicopathologic factors and tumor prognosis were evaluated. The intratumoral microvessel density (MVD) was assessed based on CD105 antigen immunoreactivity and analyzed for correlation with MTA1 protein expression.ResultsOverexpression of MTA1 was detected in 36.04 % of patients and exhibited a significant association with tumor size and MVD. Survival analysis demonstrated that both overall (OS) and disease‐free (DFS) survivals in patients overexpressing MTA1 were significantly poorer than those without MTA1 overexpression 5 years after the operation (both p < 0.001). Multivariate survival analysis demonstrated that MTA1 overexpression was an independent prognosticator for unfavorable OS and DFS (p < 0.001, respectively).ConclusionsMTA1 overexpression is frequently observed in pN0 GC patients and is significantly associated with increased angiogenesis and poor prognosis. Detection of MTA1 protein expression may help predict the relapse and prognosis of pN0 GC. Also, MTA1 protein may form a novel target for antiangiogenic therapy.
The sharp-interface limit of the Cahn–Hilliard/Navier–Stokes model for binary fluids
Authors: Magaletti F. , Picano F. , Chinappi M. , Marino L. , Casciola C. M. 
Published: January 2013

AbstractThe Cahn–Hilliard model is increasingly often being used in combination with the incompressible Navier–Stokes equation to describe unsteady binary fluids in a variety of applications ranging from turbulent two-phase flows to microfluidics. The thickness of the interface between the two bulk fluids and the mobility are the main parameters of the model. For real fluids they are usually too small to be directly used in numerical simulations. Several authors proposed criteria for the proper choice of interface thickness and mobility in order to reach the so-called ‘sharp-interface limit’. In this paper the problem is approached by a formal asymptotic expansion of the governing equations. It is shown that the mobility is an effective parameter to be chosen proportional to the square of the interface thickness. The theoretical results are confirmed by numerical simulations for two prototypal flows, namely capillary waves riding the interface and droplets coalescence. The numerical analysis of two different physical problems confirms the theoretical findings and establishes an optimal relationship between the effective parameters of the model.
Experimental investigation of axisymmetric hypersonic shock-wave/turbulent-boundary-layer interactions
Authors: Murray N. , Hillier R. , Williams S. 
Published: January 2013

AbstractThis paper presents time-averaged data for high-Reynolds-number hypersonic shock-wave/boundary-layer interactions, using a body of revolution to achieve high standards of two-dimensionality. The data are collected at nominal Mach 8.9, but a calibration is included that permits weak flow gradients in the test section to be incorporated as part of the data interpretation or flow modelling. The axisymmetric turbulent test boundary layer is developed on a hollow cylinder, aligned axially with the flow. The shock-wave interaction with this boundary layer is then generated by two separate configurations. Firstly, an impinging shock-wave case, that uses a concentric cowl to radiate an axisymmetric shock system onto the test boundary layer: for this case both an attached flow and a separated flow interaction are formed. Secondly, use of a conical-flare afterbody to produce a separated flow interaction. Quantitative data are presented for surface pressures and heat transfer, supported by some schlieren visualization and surface oil flows. A restricted CFD programme is included to assist the interpretation of the experiments.
Influence of low-frequency vibration on thermocapillary instability in a binary mixture with the Soret effect: long-wave versus short-wave perturbations
Authors: Fayzrakhmanova Irina S. , Shklyaev Sergey , Nepomnyashchy Alexander A. 
Published: January 2013

AbstractWe study the influence of low-frequency vibration on Marangoni instability in a layer of a binary mixture with the Soret effect. A linear stability analysis is performed numerically for perturbations of a finite wavelength (short-wave perturbations). Competition between long-wave and short-wave modes is found: the former ones are critical at smaller absolute values of the Soret number $\chi $, whereas the latter ones lead to instability at higher $\vert \chi \vert $. In both cases the vibration destabilizes the layer. Two variants of calculations are performed: via Floquet theory (linear asymptotic stability) and taking noise into consideration (empirical criterion). It is found that fluctuations substantially reduce the domains of stability. Further, while studying a limiting case within the empirical criterion, we have found a short-wave instability mode overlooked in former investigations of coupled Rayleigh–Marangoni convection in a layer of pure liquid.
A scaling analysis for turbulent shock-wave/boundary-layer interactions
Authors: Souverein L. J. , Bakker P. G. , Dupont P. 
Published: January 2013

AbstractA model based on mass conservation properties is developed for shock-wave/boundary-layer interactions (SWBLIs), aimed at reconciling the observed great diversity in flow organization documented in the literature, induced by variations in interaction geometry and aerodynamic conditions. It is the basis for a scaling approach for the interaction length that is valid independent of the geometry of the flow (considering compression corners and incident-reflecting shock interactions). As part of the analysis, a scaling argument is proposed for the imposed pressure jump that depends principally on the free-stream Mach number and the flow deflection angle. Its interpretation as a separation criterion leads to a successful classification of the separation states for turbulent SWBLIs (attached, incipient or separated). In addition, the dependence of the interaction length on the Reynolds number and the Mach numbers is accounted for. A large compilation of available data provides support for the validity of the model. Some general properties on the state of the flow are derived, independent of the geometry of the flow and for a wide range of Mach numbers and Reynolds numbers.
The inverse water wave problem of bathymetry detection
Authors: Vasan Vishal , Deconinck Bernard 
Published: January 2013

AbstractThe inverse water wave problem of bathymetry detection is the problem of deducing the bottom topography of the seabed from measurements of the water wave surface. In this paper, we present a fully nonlinear method to address this problem in the context of the Euler equations for inviscid irrotational fluid flow with no further approximation. Given the water wave height and its first two time derivatives, we demonstrate that the bottom topography may be reconstructed from the numerical solution of a set of two coupled non-local equations. Owing to the presence of growing hyperbolic functions in these equations, their numerical solution is increasingly difficult if the length scales involved are such that the water is sufficiently deep. This reflects the ill-posed nature of the inverse problem. A new method for the solution of the forward problem of determining the water wave surface at any time, given the bathymetry, is also presented.
Thermocapillary flow regimes and instability caused by a gas stream along the interface
Authors: Shevtsova V. , Gaponenko Y. A. , Nepomnyashchy A. 
Published: January 2013

AbstractWe present the results of a numerical study of the thermocapillary (Marangoni) convection in a liquid bridge of $\mathit{Pr}= 12$ ($n$-decane) and $\mathit{Pr}= 68$ (5 cSt silicone oil) when the interface is subjected to an axial gas stream. The gas flow is co- or counter-directed with respect to the Marangoni flow. In the case when the gas stream comes from the cold side, it cools down the interface to a temperature lower than that of the liquid beneath and in a certain region of the parameter space that cooling causes an instability due to a temperature difference in the direction perpendicular to the interface. The disturbances are swept by the thermocapillary flow to the cold side, which leads to the appearance of axisymmetric waves propagating in the axial direction from the hot to cold side. The mechanism of this new two-dimensional oscillatory instability is similar to that of the Pearson’s instability of the rest state in a thin layer heated from below (Pearson, J. Fluid Mech., vol. 4, 1958, p. 489), and it appears at the value of the transverse Marangoni number ${ \mathit{Ma}}_{\perp }^{cr} \approx 39\text{{\ndash}} 44$ lower than that of the Pearson’s instability in a horizontal layer ($48\lt { \mathit{Ma}}_{\perp }^{cr} \lt 80$, depending on the Biot number). The generality of the instability mechanism indicates that it is not limited to cylindrical geometry and might be observed in a liquid layer with cold gas stream.
Saccharomyces boulardii ameliorates clarithromycin- and methotrexate-induced intestinal and hepatic injury in rats
Authors: Duman Deniz Güney , Kumral Zarife Nigâr Özdemir , Ercan Feriha , Deniz Mustafa , Can Güray , Çağlayan Yeğen Berrak 
Published: January 2013

Saccharomyces boulardii is a probiotic used for the prevention of antibiotic-associated diarrhoea. We aimed to investigate whether S. boulardii could alter the effects of clarithromycin (CLA) and methotrexate (MTX) on oro-caecal intestinal transit and oxidative damage in rats. Rats were divided into two groups receiving a single dose of MTX (20 mg/kg) or CLA (20 mg/kg per d) for 1 week. Groups were treated with either saline or S. boulardii (500 mg/kg) twice per d throughout the experiment. The control group was administered only saline. Following decapitation, intestinal transit and inflammation markers of glutathione (GSH), malondialdehyde and myeloperoxidase were measured in intestinal and hepatic tissues. CLA and MTX increased intestinal transit, while S. boulardii treatment slowed down CLA-facilitated transit back to control level. Both MTX and CLA increased lipid peroxidation while depleting the antioxidant GSH content in the hepatic and ileal tissues. Conversely, lipid peroxidation was depressed and GSH levels were increased in the ileal and hepatic tissues of S. boulardii-treated rats. Increased ileal neutrophil infiltration due to MTX and CLA treatments was also reduced by S. boulardii treatment. Histological analysis supported that S. boulardii protected intestinal tissues against the inflammatory effects of both agents. These findings suggest that S. boulardii ameliorates intestinal injury and the accompanying hepatic inflammation by supporting the antioxidant state of the tissues and by inhibiting the recruitment of neutrophils. Moreover, a preventive effect on MTX-induced toxicity is a novel finding of S. boulardii, proposing it as an adjunct to chemotherapy regimens.
BIOSOCIAL COMPARISON OF MID-UPPER ARM CIRCUMFERENCE IN THE TWO KOREAS
Authors: SCHWEKENDIEK DANIEL 
Published: January 2013

SummaryAnthropometric differences between the two Koreas are of considerable public and scientific interest given the unique socio-political status of North Korea and the fact that the nations share the same genetic ancestry. This study provides new biosocial evidence on these differences by analysing mid-upper arm circumference (MUAC) as a human welfare indicator. This is the first study to compare the nutritional status of adults surveyed inside North Korea with South Koreans. The MUAC measurements of 2793 North Korean women obtained through a household survey conducted in 2002 were compared with those of 1428 South Korean women surveyed around 2003. Comparative analysis was conducted by plotting centiles and calculating mean differences in MUAC by age. This paper finds that the MUAC of the South Koreans was on average 2.8 cm greater than that of their North Korean peers, with MUAC gaps ranging from 1.6 cm to 3.9 cm and becoming more pronounced with age. This research confirms previous studies on height and weight in the two Germanies and in the two Koreas that have shown that biosocial performance is worse in socialist economies as compared with free-market regimes.