bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrochemical Behaviour of HOPG and CVD‐Grown Graphene Electrodes Modified with Thick Anthraquinone Films by Diazonium Reduction
Authors: Kibena Elo , Marandi Margus , Sammelselg Väino , Tammeveski Kaido , Jensen Bjarke B. E. , Mortensen Anders B. , Lillethorup Mie , Kongsfelt Mikkel , Pedersen Steen U. , Daasbjerg Kim 
Published: September 2014

AbstractHighly oriented pyrolytic graphite (HOPG) and graphene grown on Ni (Ni‐Gra) or Cu (Cu‐Gra) by chemical vapour deposition were modified with thick anthraquinone (AQ) films (7−60 nm) by redox grafting of the pertinent diazonium salt. Glassy carbon (GC) electrodes were used for comparison. The AQ‐modified GC electrodes showed excellent blocking properties towards the Fe(CN)63−/4− redox probe, although it was noted that in the case of Ni‐Gra and Cu‐Gra, the blocking ability depended strongly on the underlying substrate. Oxygen reduction studies revealed good electrocatalytic activity of AQ‐modified HOPG, Ni‐Gra, and Cu‐Gra, compared with the bare electrodes.
Nuclear fusion as a massive, clean, and inexhaustible energy source for the second half of the century: brief history, status, and perspective
Authors: Sánchez Joaquin 
Published: September 2014

AbstractFusion energy, based on the use of broadly available inexhaustible resources as lithium and deuterium and with minimal impact to the environment, aims at a change in the energy supply paradigm: instead of its current dependence on natural resources and environmental impact, energy would become a technology‐dependent resource with unlimited adaptive availability and whose unit cost should decrease as technology progresses. This article intends to give a picture of where fusion research stands today and the perspectives: the achievements, the difficulties, the current status, marked by the construction of the ITER experiment which will demonstrate the scientific feasibility of fusion power, and the perspectives toward the first demonstration power plant, DEMO, which, according to the European Roadmap, could start the construction shortly after the full power experiments in ITER (<2030) and be in full operation, generating net electricity into the grid, by 2050.
Reconstructing the development of sampled sites on fluvial island surfaces of the Tagliamento River, Italy, from historical sources
Authors: Mardhiah Ulfah , Rillig Matthias C , Gurnell Angela 
Published: September 2014

AbstractIn parallel with research on surface sediment characteristics of evolving island features (patches) along an island‐braided reach of the Tagliamento River, Italy, the present research reconstructed the development of the sampled sites using historical information coupled with field measurements. Since any field sediment sampling programme inevitably focuses on small areas (of the order of a few metres), the historical sources were assessed bearing in mind their spatial resolution and geographical accuracy in relation to the size of the sampled sites, and the information they could provide regarding the historical evolution of those sites.The analysis combined four sources of information: (i) river stage records revealed flood events that had the potential to reset bar surfaces and float in wood and seeds to initiate vegetation colonization; (ii) oblique ground photographs identified areas of the river's active corridor where riparian vegetation colonization appeared to have been initiated by specific flood events; (iii) dendrochronology was used to estimate the age of sampled sites; (iv) field‐measured geographical locations of the sampled sites were combined with historical vertical areal imagery to further establish sampling site age and changes in vegetation cover from 1944 to 2012.A chronosequence of sampled sites (0, 2, 8, 12, 40 years) was established. Vegetation colonization and island development showed a statistically significant development trajectory among sites of each age across the 40 year period following formative floods in 1965–1966, 2000, 2004 and a flow pulse in 2010. The trajectory progressed through pioneer and building island stages until vegetated areas became part of established islands. Evidence from the younger sites indicates that the pioneer island phase lasts up to eight years. Evidence from the oldest site indicates a building island phase lasting a maximum of 30 years, but probably a lot less. Copyright © 2014 John Wiley & Sons, Ltd.
In vivo and in vitro changes in neurochemical parameters related to mercury concentrations from specific brain regions of polar bears (Ursus maritimus)
Authors: Krey Anke , Kwan Michael , Chan Hing Man 
Published: September 2014

Abstract

Mercury (Hg) has been detected in polar bear brain tissue, but its biological effects are not well known. Relationships between Hg concentrations and neurochemical enzyme activities and receptor binding were assessed in the cerebellum, frontal lobes, and occipital lobes of 24 polar bears collected from Nunavik (Northern Quebec), Canada. The concentration–response relationship was further studied with in vitro experiments using pooled brain homogenate of 12 randomly chosen bears. In environmentally exposed brain samples, there was no correlative relationship between Hg concentration and cholinesterase (ChE) activity or muscarinic acetylcholine receptor (mAChR) binding in any of the 3 brain regions. Monoamine oxidase (MAO) activity in the occipital lobe showed a negative correlative relationship with total Hg concentration. In vitro experiments, however, demonstrated that Hg (mercuric chloride and methylmercury chloride) can inhibit ChE and MAO activities and muscarinic mAChR binding. These results show that Hg can alter neurobiochemical parameters but the current environmental Hg exposure level does have an effect on the neurochemistry of polar bears from northern Canada. Environ Toxicol Chem 2014;33:2463–2471. © 2014 SETAC
USING MODERN STATISTICAL METHODS TO IMPROVE THE PRESENTATION OF THE ANNUAL SUMMARIES OF GRE CANDIDATE BACKGROUND DATA
Authors: Holland Paul W. , Thayer Dorothy T. 
Published: September 2014

ABSTRACTThis project has three separate components. The first is an analysis of the background data for GRE test takers using log‐linear models for multi‐way cross‐classifications. The second is the computation of ethnic group GRE verbal and quantitative score means that are standardized for background data. The third is an analysis of the non‐responses to the questions in the GRE background questionnaire. The data used in the analyses are from the 1975–76 and 1976–77 testing years.An appendix is included that gives versions of the published tables separately for graduate students and nongraduate students. This report was intended as an internal working paper for use by ETS staff.
SECTION PRE‐EQUATING IN THE PRESENCE OF PRACTICE EFFECTS
Authors: Holland Paul W. , Thayer Dorothy T. 
Published: September 2014

ABSTRACTSection pre‐equating (SPE) is a new method for equating tests that was developed in response to test disclosure legislation. It is designed to equate a new test to an old test prior to the actual use of the new test, and makes extensive use of experimental sections of a testing instrument. This paper extends the theory behind SPE to allow for the effects of practice on both the old and the new tests, and gives a unified and generalized account of SPE.
SPECULATIONS ON THE FUTURE OF TEST DESIGN
Authors: Bejar Isaac I. 
Published: September 2014

ABSTRACTThe paper discusses the potential benefits of integrating technology, cognitive science, and psychometric theory. It is argued that even though adaptive testing, as currently implemented, is an important achievement, it will be necessary to pay close attention to the psychological foundation of tests to continue advancing the state of the art. Such an effort requires construct validation in the broadest sense, as well as focusing on items and why they differ with respect to psychometric parameters, specially difficulty. This approach opens the possibility of generating items with better control of their psychometric characteristics and ultimately the development of computer‐based tests that are solidly anchored in psychological theory.
A PROFILE OF PREPARATION IN ENGLISH: PHASE II
Authors: Ward William C. , Carlson Sybil B. 
Published: September 2014

ABSTRACTThis is the report of a project that was undertaken to develop and validate a method for collecting and reporting information about students' preparation in English for college‐level work. Information was gathered from students through a self‐report inventory, Experiences in English. Then a prototype report was prepared in the form of a profile–an evaluation of a student's strengths and weaknesses in each of several major aspects of use of the language.
ON STATE EDUCATION STATISTICS
Authors: Wainer Howard , Rosenbaum Paul R. , Swinton Spencer , Wang Minhwei 
Published: September 2014

SUMMARYState Education Statisticsis a table of information, aggregated to the state level. Its goal appears to be that of a thermometer to measure the health of the American educational system. As such, its usefulness is limited by three problems:Some outcome variables–ACT and SAT test scores–are produced by a highly self‐selected sample of individuals, so that the differences observed in outcome can be caused by differences in performance, differences in selection ratio and/or differences in selection rules. We were unable to disentangle these through statistical adjustments.Some input variables were calculated on the population as a whole (i.e., per capita income, average teachers' salary) rather than on the group characterized by the outcome variable (i.e., those individuals taking the SAT). These are often profoundly different and can cause substantial biases in the estimation of statistical measures of the interrelationships among the variables.Some input variables are inappropriately measured or scaled for the purposes intended. For example, teachers' salaries are given in current rather than constant dollars. Thus, one might conclude that over the ten years considered teachers' salaries went up 81%, rather than the more correct conclusion that, in constant dollars, they declined 20%.Among the recommendations proposed to solve these problems is an expansion of the National Assessment of Educational Progress (NAEP) to allow accurate state estimates of students performance, as well as expanding the range of areas covered to more fully measure the section of the students' population intending postsecondary education.
FITTING ITEM CHARACTERISTIC CURVES WITH SPLINE FUNCTIONS
Authors: Winsberg Suzanne , Thissen David , Wainer Howard 
Published: September 2014

ABSTRACTIn most item response theory models a particular mathematical form is assumed for all item characteristic curves, e.g., a logistic function. It could be desirable, however, to estimate the shape of the item characteristic curves without prior restrictive assumptions about its mathematical form. We have developed a practical method of estimating the shape of item response functions leading to smooth flexible functions and numerically stable calculations. In our approach the probability of success of an item is represented as a monotone function of the ability evaluated by the item. The function is represented as a monotone spline. We use the technique developed by Bock and Aitkin (1981) for marginal maximum likelihood estimation of the item parameters. Examples of real and artificial data are presented.
SEX DIFFERENCES IN THE ACADEMIC PERFORMANCE OF SCHOLASTIC APTITUDE TEST TAKERS
Authors: Clark Mary Jo , Grandy Jerilee 
Published: September 2014

ABSTRACTThe number of women college students has increased dramatically over the past fifteen years; in this same time period, the average College Board Scholastic Aptitude Test (SAT) scores for women have declined more than the scores for men. This study summarizes recent evidence concerning the academic performance of women and men by examining sex differences among (1) all SAT takers, (2) test takers grouped by anticipated major field of study, and (3) college freshman year courses and grades.Three major research questions guided this study: Are there consistent differences in the intellectual abilities of men and women? Do precollege admissions variables predict college performance with equal accuracy for women and men? Have the contents or structure of the SAT contributed to observed sex differences in performance on the test?Though the men and women who take the SAT differ in high school courses and grade point average, major field and career interests, and socioeconomic backgrounds, neither these differences nor research evidence on differential cognitive functioning were found sufficient to account for all of the observed sex differences in performance on the SAT. Some but not all of the male‐female differences in scores on the mathematics portion of the SAT were accounted for by differences in the depth and recency of course preparation. The observed‐first‐year college grades of women were slightly underpredicted by test scores and high school grades, but the magnitude of the underprediction was very small. While specific changes in the contents or structure of the SAT could not be associated with score changes, it seems likely that numerous small adjustments have played some part in recent shifts among the average test scores of women and men.Consistent with recent literature on sex differences in cognitive performance, this study concludes that sex‐related SAT differences are very small relative to the generally similar levels of performance by men and women, and that using both test scores and high school records to predict first‐year college grades continues to work reasonably well for both sexes.
RECENT DEVELOPMENTS IN THE FACTOR ANALYSIS OF CATEGORICAL VARIABLES
Authors: Mislevy Robert J. 
Published: September 2014

ABSTRACTDespite known shortcomings of the procedure, exploratory factor analysis of dichotomous test items has been limited, until recently, to unweighted analyses of matrices of tetrachoric correlations. Superior methods have begun to appear in the literature, in professional symposia, and in computer programs. This paper places these developments in a unified framework, from a review of the classical common factor model for measured variables through generalized least squares and marginal maximum likelihod solutions for dichotomous data. Further extensions of the model are also reported as work in progress.
COLLEGE BOARD COMPUTERIZED PLACEMENT TESTS
Authors: Ward William C. , Kline Roberta G. , Flaugher Jan 
Published: September 2014

ABSTRACTSeventeen two‐ and four‐year institutions participated in pilot testing of the College Board Computerized Placement Tests during 1984 and 1985. Data were available for over 2,500 students who took one or more modules of the adaptive test; participating institutions planned to test at least 2,000 more by the end of 1985. In most institutions examinees were volunteers currently enrolled in English, reading, or mathematics courses.Students taking part in the 1984 pilot completed a questionnaire describing their reactions, and many took a short paper and pencil test for comparison with the computerized tests. In both years of pilot activity, students' grades in relevant courses and their scores on other tests used for placement were obtained.Reactions of students and of faculty and staff were very favorable. Both groups found the computer easy to use; both liked especially the adaptation of the test to a student's level of skills and the ability to obtain immediate score reports.Analyses of the relations between test scores and end‐of‐term grades were done separately by level of course (developmental or introductory college‐level). Grades in single courses constitute a very fallible criterion, confounded by a number of factors. Nonetheless, moderate correlations with grades, with median values generally in the range from .30 to .40, were found for all categories of courses examined except for developmental mathematics courses; in the latter, the median correlations were over .50. These coefficients are similar in magnitude to those found in studies with professionally constructed paper and pencil test batteries.A few samples provided data appropriate for a comparison of relations to grades for sex and ethnic subgroups. There was no evidence of differential prediction for these groups, but, with small sample sizes and volunteer examinees, these results are far from definitive.No specific contrasts can be made of relations to grades of the computerized tests and other placement tests given to pilot examinees; in most instances the other tests available were institution‐specific, and the sample sizes were too small to permit confident generalizations about differences in the relations. Over all samples and courses for which data are available, the computerized test scores showed higher correlations with grades than did scores from paper and pencil tests in 59% of the possible contrasts.
GRE VERBAL ANALOGY ITEMS: EXAMINEE REASONING ON ITEMS
Authors: Duran Richard P. , Enright Mary K. , Peirce Leslie P. 
Published: September 2014

ABSTRACTInformation about how GRE examinees solve verbal analogy problems was obtained in this study through protocol analysis. High‐ and low‐ability subjects who had recently taken the GRE General Test were asked to “think aloud” as they worked through eight analogy items. These items varied factorially on the dimensions of vocabulary difficulty (easy vs. difficult), relationship difficulty (easy vs. difficult), and stem‐key correspondence (independent vs. overlapping). A scoring system was developed that included three phases: (i) a cognitive process analysis, (ii) a global description of the subjects' strategies, and (iii) an evaluation of their performance. Overall we found that vocabulary and correspondence tended to have multiple effects on how subjects solved analogies and affected whether they solved them correctly. On the other hand, relationship difficulty tended to affect whether or not subjects achieved correct solutions but not how they attained solutions. As expected, high‐ability subjects tended to use higher‐level or more sophisticated strategies more often than low‐ability subjects. However, the use of higher‐level strategies was common for both groups of subjects. The results are compared with those reported in the cognitive science literature. In addition, the implication of these results for test development and the usefulness of the protocol methodology are discussed.
ISSUES IN RACE/ETHNICITY IDENTIFICATION PROCEDURES IN THE NATIONAL ASSESSMENT OF EDUCATIONAL PROGRESS, PART I: A COMPARISON OF OBSERVER REPORTS AND SELF‐IDENTIFICATION
Authors: Rivera Charlene , Pennock‐Roman Maria 
Published: September 2014

ABSTRACTIn this investigation, the validity of observer reports versus student self‐reports of race and ethnicity in the National Assessment of Educational Progress (NAEP) for ages 9, 13, and 17 were evaluated. Data from seven surveys (1975‐1984) were analyzed, with sample sizes ranging from 15,859 to 38,899. While the concordance between the two methods for both White and Black students was very high (95% or better), the two classifications gave very disparate results for the other four racial/ethnic groups. For example, observers undercounted self‐identified Hispanic 17–year‐olds by 25% to 48%. Language background was significantly (p < .0001) more consistent with self‐identification than with observer reports for 17‐year‐old Hispanic students which showed that self reports were more valid than observed ethnicity in this age group. However, the results for ages 9 and 13 were less clear‐cut. The implications of the findings for continuity in NAEP data sets and the validity of reported group achievement data for Hispanic students are discussed.
FACTORS AFFECTING DIFFERENTIAL ITEM FUNCTIONING FOR BLACK EXAMINEES ON SCHOLASTIC APTITUDE TEST ANALOGY ITEMS1
Authors: Schmitt Alicia P. , Bleistein Carole A. 
Published: September 2014

ABSTRACTThe purpose of the present investigation was to identify item factors that may contribute to differential item functioning (DIF) for Black examinees on Scholastic Aptitude Test (SAT) analogy items. This research was considered necessary because analogy items have repeatedly been identified as differentially more difficult for Black examinees. The research was performed in two steps. Initially items in three forms were classified according to several possible explanatory factors. Preliminary analyses identified several factors that seemed to affect DIF for Black examinees. In order to confirm these hypothesized factors, a second step involved classifying and analyzing analogy items from two additional SAT forms.The most significant finding is that Black students appear to need more time to complete the SAT verbal sections than White students with comparable total SAT verbal scores. This differential speededness effect makes analogy items appear differentially more difficult for Black examinees. Once differential item functioning statistics were corrected for speededness, a smaller number of analogy items were identified as differentially more difficult. In addition, evaluation of the hypothesized factors showed that some of the factors are interdependent and no clear distinction could be made to determine out their individual effects. These item factors are: item position within each analogy set, difficulty, subject matter content, and level of abstractness. The effects of homographs and semantic relationship types are also confounded with the previous factors. The only factor that seemed to be independent was “vertical relationships”. In general, a vertical or word associative answering strategy seems to be more consistently used by Black examinees on those items with negative DIF.Generalizations to be drawn from these results are limited because the analyses are based on regular administration items which tend to have several factors operating in a single item and which contain infrequent occurrence of some factors. At this stage, these results provide a clearer picture of how comparable Black and White students respond on analogy items and the factors that might influence their performance.
EXPLOITING AUXILIARY INFORMATION ABOUT ITEMS IN THE ESTIMATION OF RASCH ITEM DIFFICULTY PARAMETERS
Authors: Mislevy Robert J. 
Published: September 2014

ABSTRACTStandard procedures for estimating the item parameters in IRT models make no use of auxiliary information about test items, such as their format or content, or the skills they require for solution. This paper describes a framework for exploiting this information, thereby enhancing the precision and stability of item parameter estimates and providing diagnostic information about items' operating characteristics. The principles are illustrated in a context for which a relatively simple approximation is available: empirical Bayes estimation of Rasch item difficulty parameters.