catcher: A software program to detect answer copying in multiple-choice tests based on nominal response model

Cataloged from PDF version of article.catcher is a software program designed to compute the v index, a common statistical index for the identification of collusions (cheating) among examinees taking an educational or psychological test. It requires (a) responses and (b) ability estimations of individuals, and (c) item parameters to make computations and outputs the results of the analyses in two text files. The program uses the nominal response model to estimate v index and is based on residuals between expected and observed values of matched answers between examinee pairs (copier and source) by considering correct and incorrect answers, conditioning on source’s answers, copier’s ability level, and item parameters

Reliability-Related Issues in the Context of Student Evaluations of Teaching in Higher Education

Cataloged from PDF version of article.Student evaluations of teaching (SET) have been the principal instrument to elicit students’ opinions in higher education institutions. Many decisions, including high-stake ones, are made based on SET scores reported by students. In this respect, reliability of SET scores is of considerable importance. This paper has an argument that there are some problems in choosing and using of reliability indices in SET context. Three hypotheses were tested: (i) using internal consistency measures is misleading in SET context since the variability is mainly due to disagreement between students’ ratings, which requires use of inter-rater reliability coefficients, (ii) number of minimum feedbacks is not achieved in most of the classes, resulting unreliable decisions, and (iii) calculating reliability coefficient assuming a common factor structure across all classes is misleading because a common model may not be tenable for all. Results showed that use of internal consistency only to assess reliability of SET scores may result in wrong decisions. Considerable large numbers of missing feedbacks were observed to achieve acceptable reliability levels. Findings also indicated that factorial model differed across several groups

Profiling Instructional Effectiveness to Reveal Its Relationship to Learning

The purpose of the present study is to define instructional profiles and investigate the relationship between these profiles and learning indicators such as end-of-semester grades and self-reported amount of learning. Instructional profiles were obtained using a segmentation method. Student ratings were used as indicators of instructional effectiveness. Results revealed that instructors who receive higher scores from students seem to be effective instructors in learning. However, instructors with high ratings from students did not receive high scores for all measures of instructional effectiveness. Effective instructors seem to have varying scores due to the imperfect relationship between instructional effectiveness and learning. It can be concluded that the definition of an effective instructor can vary across subgroups. For an instructor to be defined as effective, it is not necessary for them to receive higher scores for all measures. Low-rated aspects of effectiveness can be compensated for by showing high performance in other areas. Based on the results of the present study, instructional profiles or any other related traits should be investigated under subgroups that show differences. © 2013 De La Salle University

Mathematical knowledge and skills expected by higher education in engineering and the social sciences: Implications for high school mathematics curriculum

Cataloged from PDF version of article.One important function of school mathematics curriculum is to prepare high school students with the knowledge and skills needed for university education. Identifying them empirically will help making sound decisions about the contents of high school mathematics curriculum. It will also help students to make informed choices in course selection at high school. In this study, we surveyed university faculty members who teach first year university students about the mathematical knowledge and skills that they would like to see in incoming high school graduates. Data were collected from 122 faculty members from social science (history, law, psychology) and engineering departments (electrical/electronics and computer engineering). Participants were asked to indicate which high school mathematics topics and skills they thought were important to be successful at university education in their field. Results were compared across social science and engineering departments. Implications were drawn for curriculum specialists, students, and mathematics educators

Mathematical knowledge and skills expected by higher education in engineering and the social sciences: Implications for high school mathematics curriculum

One important function of school mathematics curriculum is to prepare high school students with the knowledge and skills needed for university education. Identifying them empirically will help making sound decisions about the contents of high school mathematics curriculum. It will also help students to make informed choices in course selection at high school. In this study, we surveyed university faculty members who teach first year university students about the mathematical knowledge and skills that they would like to see in incoming high school graduates. Data were collected from 122 faculty members from social science (history, law, psychology) and engineering departments (electrical/electronics and computer engineering). Participants were asked to indicate which high school mathematics topics and skills they thought were important to be successful at university education in their field. Results were compared across social science and engineering departments. Implications were drawn for curriculum specialists, students, and mathematics educators. © 2015 by iSER

TRP genes family expression in colorectal cancer

Colorectal cancer (CRC) is the most common cancer of the gastrointestinal tract. Different factors are responsible for the development of CRC. Transient Receptor Potential (TRP) which is an important component of calcium channel is associated with several pathological conditions like cancer, neurodegenerative and cardiovascular diseases. Thirty members of the family of TRP ion channel in mammals have been determined till now. The aim of this study is to investigate TRPM, TRPV and TRPC gene expression levels in tumor tissues of CRC patients and to analyze the relationship of expression in tumor tissue of CRC with other known prognostic factors. Material and Methods: In this study, 93 CRC patients were included. The level of TRP gene expression in paraffin blocks of normal and cancerous colorectal tissue samples were studied at the level of mRNA with Real-time PCR. Results: The mRNA expression level of TRPV3, TRPV4, TRPV5, TRPM4 and TRPC6 genes in 37 female and 56 male patients diagnosed with CRC was revealed lower in tumor tissue as compared to normal tissue (p < 0.05). No statistically significant differences of mRNA expression levels of other TRP genes were found. Conclusions: TRP gene family like TRPV3, TRPV4, TRPV5, TRPM4 and TRPC6 may be thought as potential genes contributing to tumorigenesis as their expression decreases in CRC as compared to normal tissues. Key Words: colorectal cancer, TRP genes family: TRPV3, TRPV4, TRPV5, TRPM4, TRPC6, mRNA expression

Non-destructive determination of fat content in green hams using ultrasound and X-rays

[EN] This work addresses the use of ultrasound (US) and medical dual energy X-ray absorptiometry methods to predict the fat content in green pork hams. Ultrasonic velocity (õ) and X-ray absorption were measured in 78 green hams. An increase in the fat content involved an increase in õ and a decrease in the X-ray attenuationmeasured at 2 °C.Models developed to predict the fat content fromthe ultrasonic velocity or X-ray parameters provided errors of 2.97% and 4.65%, respectively. The combination of both US and X-ray technologies did not improve prediction accuracy. These models allowed green hams to be classified into three levels of fatness, with 88.5% and 65.4% of the hams correctly classified when using models based on ultrasonic and X-ray parameters, respectively. Therefore, US and X-rays emerge as useful quality control technologies with which to estimate the fat content in green pork hamsThis work was supported by the spanish Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria (INIA) (contracts n. RTA2010-00029-CO4-01/02) and by Universitat Politecnica de Valencia (UPV) through the FPI grant given to Marta de Prados (SP-1.2011-S1-2757).Prados Pedraza, MD.; Fulladosa, E.; Gou, P.; Muñoz, I.; García Pérez, JV.; Benedito Fort, JJ. (2015). Non-destructive determination of fat content in green hams using ultrasound and X-rays. Meat Science. 104:37-43. https://doi.org/10.1016/j.meatsci.2015.01.015S374310

Metformin inhibits melanoma development through autophagy and apoptosis mechanisms

Metformin is the most widely used antidiabetic drug because of its proven efficacy and limited secondary effects. Interestingly, recent studies have reported that metformin can block the growth of different tumor types. Here, we show that metformin exerts antiproliferative effects on melanoma cells, whereas normal human melanocytes are resistant to these metformin-induced effects. To better understand the basis of this antiproliferative effect of metformin in melanoma, we characterized the sequence of events underlying metformin action. We showed that 24 h metformin treatment induced a cell cycle arrest in G0/G1 phases, while after 72 h, melanoma cells underwent autophagy as demonstrated by electron microscopy, immunochemistry, and by quantification of the autolysosome-associated LC3 and Beclin1 proteins. In addition, 96 h post metformin treatment we observed robust apoptosis of melanoma cells. Interestingly, inhibition of autophagy by knocking down LC3 or ATG5 decreased the extent of apoptosis, and suppressed the antiproliferative effect of metformin on melanoma cells, suggesting that apoptosis is a consequence of autophagy. The relevance of these observations were confirmed in vivo, as we showed that metformin treatment impaired the melanoma tumor growth in mice, and induced autophagy and apoptosis markers. Taken together, our data suggest that metformin has an important impact on melanoma growth, and may therefore be beneficial in patients with melanoma

Monte Carlo study of the effects of system geometry and antiscatter grids on cone-beam CT scatter distributions

Purpose: The proliferation of cone-beam CT (CBCT) has created interest in performance optimization,with x-ray scatter identifie among the main limitations to image quality. CBCT often contends with elevated scatter, but the wide variety of imaging geometry in different CBCT configuration suggests that not all configuration are affected to the same extent. Graphics processing unit (GPU) accelerated Monte Carlo (MC) simulations are employed over a range of imaging geometries to elucidate the factors governing scatter characteristics, effica y of antiscatter grids, guide system design, and augment development of scatter correction. Methods: A MC x-ray simulator implemented on GPU was accelerated by inclusion of variance reduction techniques (interaction splitting, forced scattering, and forced detection) and extended to include x-ray spectra and analytical models of antiscatter grids and flat-pane detectors. The simulator was applied to small animal (SA), musculoskeletal (MSK) extremity, otolaryngology (Head), breast, interventional C-arm, and on-board (kilovoltage) linear accelerator (Linac) imaging, with an axis-todetector distance (ADD) of 5, 12, 22, 32, 60, and 50 cm, respectively. Each configuratio was modeled with and without an antiscatter grid and with (i) an elliptical cylinder varying 70–280 mm in major axis; and (ii) digital murine and anthropomorphic models. The effects of scatter were evaluated in terms of the angular distribution of scatter incident upon the detector, scatter-to-primary ratio (SPR), artifact magnitude, contrast, contrast-to-noise ratio (CNR), and visual assessment. Results: Variance reduction yielded improvements in MC simulation efficien y ranging from ∼17-fold (for SA CBCT) to ∼35-fold (for Head and C-arm), with the most significan acceleration due to interaction splitting (∼6 to ∼10-fold increase in efficien y). The benefi of a more extended geometry was evident by virtue of a larger air gap—e.g., for a 16 cm diameter object, the SPR reduced from 1.5 for ADD = 12 cm (MSK geometry) to 1.1 for ADD = 22 cm (Head) and to 0.5 for ADD = 60 cm (C-arm). Grid efficien y was higher for configuration with shorter air gap due to a broader angular distribution of scattered photons—e.g., scatter rejection factor ∼0.8 for MSK geometry versus ∼0.65 for C-arm. Grids reduced cupping for all configuration but had limited improvement on scatterinduced streaks and resulted in a loss of CNR for the SA, Breast, and C-arm. Relative contribution of forward-directed scatter increased with a grid (e.g., Rayleigh scatter fraction increasing from ∼0.15 without a grid to ∼0.25 with a grid for the MSK configuration) resulting in scatter distributions with greater spatial variation (the form of which depended on grid orientation). Conclusions: A fast MC simulator combining GPU acceleration with variance reduction provided a systematic examination of a range of CBCT configuration in relation to scatter, highlighting the magnitude and spatial uniformity of individual scatter components, illustrating tradeoffs in CNR and artifacts and identifying the system geometries for which grids are more beneficia (e.g., MSK) from those in which an extended geometry is the better defense (e.g., C-arm head imaging). Compact geometries with an antiscatter grid challenge assumptions of slowly varying scatter distributions due to increased contribution of Rayleigh scatter.The research was supported by academic-industry partnership with Carestream Health Inc. (Rochester, NY) and National Institutes of Health (NIH) Grant No. 2R01-CA-112163. A. Sisniega is supported by FPU grant (Spanish Ministry of Education), AMIT project, RECAVA-RETIC Network, Project Nos. TEC2010-21619- C04-01, TEC2011-28972-C02-01, and PI11/00616 (Spanish Ministry of Science and Education), ARTEMIS program (Comunidad de Madrid), and PreDiCT-TB partnership.Publicad