WorldWideScience

Sample records for vhs item number

  1. VHS virus - present situation

    DEFF Research Database (Denmark)

    Olesen, Niels Jørgen; Skall, Helle Frank

    of the worldwide distribution of the disease will be given. Virus evolution: Recent studies indicate that only a few amino acid changes in the structural proteins of VHSV can change the virulence patterns significantly, thereby coming closer to assessing the risk of none to low virulent viruses becoming high......Geographic distribution: VHSV can be divided into 4 genotypes and at least 8 subtypes and there is a close linkage between genotypes, geographic range and affected fish species. VHS is still only reported from the Northern hemisphere- and while countries like Denmark, Norway and England have freed...... themselves for VHS, several countries are still struggling with the disease. An update on the recent VHS outbreaks in rainbow trout in Iran, in olive flounder in Korea, in wrasse in Scotland, in turbot in Turkey, in a number of fish species in the great lakes in USA and Canada, and a general overview...

  2. VHS virus - present situation

    DEFF Research Database (Denmark)

    Skall, Helle Frank; Olesen, Niels Jørgen

    2015-01-01

    of the worldwide distribution of the disease will be given. Virus evolution: Recent studies indicate that only a few amino acid changes in the structural proteins of VHSV can change the virulence patterns significantly, thereby coming closer to assessing the risk of none to low virulent viruses becoming high......Geographic distribution: VHSV can be divided into 4 genotypes and at least 8 subtypes and there is a close linkage between genotypes, geographic range and affected fish species. VHS is still only reported from the Northern hemisphere- and while countries like Denmark, Norway and England have freed...... themselves for VHS, several countries are still struggling with the disease. An update on the recent VHS outbreaks in rainbow trout in Iran, in olive flounder in Korea, in wrasse in Scotland, in turbot in Turkey, in a number of fish species in the great lakes in USA and Canada, and a general overview...

  3. Sanitation of viral haemorrhagic septicaemia (VHS)

    DEFF Research Database (Denmark)

    Olesen, Niels Jørgen

    1998-01-01

    A sanitation programme for stamping-out viral haemorrhagic septicaemia (VHS) was implemented in Denmark in 1965. The programme has resulted in a dramatic reduction in the number of infected rainbow trout farms, from approximate to 400 to 26. The programme is carried out on a voluntary basis...

  4. 9 CFR 83.4 - VHS-regulated fish and VHS-regulated areas.

    Science.gov (United States)

    2010-01-01

    ... been isolated in cell culture or other assay determined by the Administrator to be adequate to detect... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false VHS-regulated fish and VHS-regulated... HEMORRHAGIC SEPTICEMIA § 83.4 VHS-regulated fish and VHS-regulated areas. (a)(1) APHIS will list as a VHS...

  5. VHS Movies: Perturbations for Morphogenesis.

    Science.gov (United States)

    Holmes, Danny L.

    This paper discusses the concept of a family system in terms of an interactive system of interrelated, interdependent parts and suggests that VHS movies can act as perturbations, i.e., change promoting agents, for certain dysfunctional family systems. Several distinct characteristics of a family system are defined with particular emphasis on…

  6. An EPQ model with imperfect items using interval grey numbers

    Directory of Open Access Journals (Sweden)

    Erdal Aydemir

    2015-01-01

    Full Text Available The classic economic production quantity (EPQ model has been widely used to determine the optimal production quantity. However, the analysis for finding an EPQ model has many weaknesses which lead many researchers and practitioners to make extensions in several aspects on the original EPQ model. The basic assumption of EPQ model is that 100% of manufactured products are non-defective that is not valid for many production processes generally. The purpose of this paper is to develop an EPQ model with grey demand rate and cost values with maximum backorder level allowed with the good quality items in units under an imperfect production process. The imperfect items are considered to be low quality items which are sold to a particular purchaser at a lower price and, the others are reworked and scrapped. A mathematical model is developed and then an industrial example is presented on the wooden chipboard production process for illustration of the proposed model.

  7. Immunity to VHS virus in rainbow trout

    DEFF Research Database (Denmark)

    Lorenzen, Niels; Olesen, Niels Jørgen; Koch, C.

    1999-01-01

    following vaccination with naked DNA encoding the G protein under the control of a CMV promotor. Genetic resistance to VHS would be a desirable alternative to vaccination but the time required to obtain this makes it a long-time goal. Results from breeding programs in France and Denmark nevertheless...... indicate that such a strategy may provide considerable improvement in resistance....

  8. 9 CFR 83.3 - Interstate movement of live VHS-regulated fish species from VHS-regulated areas.

    Science.gov (United States)

    2010-01-01

    ... aquatic animal health. (b) Live VHS-regulated fish may be moved interstate directly to a slaughtering... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Interstate movement of live VHS-regulated fish species from VHS-regulated areas. 83.3 Section 83.3 Animals and Animal Products ANIMAL AND...

  9. Molecular tracing of VHS in Denmark

    DEFF Research Database (Denmark)

    Mikkelsen, Susie Sommer; Schuetze, H.; Korsholm, H.

    and scenario-simulation models to identify important factors for the spread of disease and to develop and evaluate new control strategies. Viral haemorrhagic septicaemia Virus (VHSV) is one of the most important viral fish diseases and is widely spread all over Europe and creates significant losses every year...... in Denmark and to look into the spread of the disease over a historical period as well as the effectiveness of containment and eradication programmes. Molecular tracing shows that the numerous VHS outbreaks in marine fish farms were due to stocking these with VHS infected rainbow trout in the incubation......MOLTRAQ is a pan-European project that aims to increase knowledge on a wide array of economically important viral diseases in fish and molluscs on both the epidemiological and the genetic level. It centers on the use of spatio-temporal and phylogenetic information to create phylogeographic...

  10. The Tipping Point: F-Score as a Function of the Number of Retrieved Items

    DEFF Research Database (Denmark)

    Guns, Raf; Lioma, Christina; Larsen, Birger

    2012-01-01

    One of the best known measures of information retrieval (IR) performance is the F-score, the harmonic mean of precision and recall. In this article we show that the curve of the F-score as a function of the number of retrieved items is always of the same shape: a fast concave increase to a maximu...

  11. Memory for melodies in unfamiliar tuning systems: Investigating effects of recency and number of intervening items.

    Science.gov (United States)

    Herff, Steffen A; Olsen, Kirk N; Dean, Roger T; Prince, Jon

    2017-05-26

    In a continuous recognition paradigm, most stimuli elicit superior recognition performance when the item to be recognised is the most recent stimulus (a recency-in-memory effect). Furthermore, increasing the number of intervening items cumulatively disrupts memory in most domains. Memory for melodies composed in familiar tuning systems also shows superior recognition for the most recent melody, but no disruptive effects from the number of intervening melodies. A possible explanation has been offered in a novel regenerative multiple representations (RMR) conjecture. The RMR assumes that prior knowledge informs perception and perception influences memory representations. It postulates that melodies are perceived, thus also represented, simultaneously as integrated entities and also their components (such as pitches, pitch intervals, short phrases, and rhythm). Multiple representations of the melody components and melody as a whole can restore one another, thus providing resilience against disruptive effects from intervening items. The conjecture predicts that melodies in an unfamiliar tuning system are not perceived as integrated melodies and should: a) disrupt recency-in-memory advantages; and b) facilitate disruptive effects from the number of intervening items. We test these two predictions in three experiments. Experiments 1 and 2 show that no recency-in-memory effects emerge for melodies in an unfamiliar tuning system. In Experiment 3, disruptive effects occurred as the number of intervening items and unfamiliarity of the stimuli increased. Overall, results are coherent with the predictions of the RMR conjecture. Further investigation of the conjecture's predictions may lead to greater understanding of the fundamental relationships between memory, perception, and behavior.

  12. About viral hemorrhagic septicemia (VHS) virus. Potential threat of Great Lakes VHS virus in Western United States

    Science.gov (United States)

    Bartholomew, Jerri L; Kurath, Gael; Emmenegger, Evi

    2011-01-01

    Viral hemorrhagic septicemia (VHS) is a disease caused by a virus (VHSV). There are different strains of the virus that can infect marine and freshwater fish species, and the different strains may affect species differently. VHSV has recently invaded the Great Lakes, resulting in many large-scale fish die-offs and new regulatory restrictions for aquaculture throughout the region.

  13. Number Right Scores as a Function of Item Arrangement, Knowledge of Arrangement, and Test Anxiety.

    Science.gov (United States)

    Plake, Barbara S.; And Others

    Effects of item arrangement (easy-hard, uniform, and random), test anxiety, and sex on a 48-item multiple-choice mathematics test assembled from items of the American College Testing Program and taken by motivated upper level undergraduates and beginning graduate students were investigated. Four measures of anxiety were used: the Achievement Test…

  14. Reducing the item number to obtain the same-length self-assessment scales: a systematic approach using result of graphical loglinear rasch models

    DEFF Research Database (Denmark)

    Nielsen, Tine; Kreiner, Svend

    2011-01-01

    approach to item reduction based on results of graphical loglinear Rasch modeling (GLLRM) was designed. This approach was then used to reduce the number of items in the subscales of the R-D-LSI which had an item-length of more than seven items, thereby obtaining the Danish Self-Assessment Learning Styles...

  15. Is this charred material from a VHS video cassette?

    Science.gov (United States)

    Fruchtenicht, Tara; Blackledge, Robert D.; Williams, Teresa R.

    2010-06-01

    At his residence, a victim in a double homicide had installed a home-built video surveillance system. The suspects either knew of or discovered this system and removed it. In a backyard at a location associated with the suspects was a barrel used for burning trash. Could charred debris recovered from a metal bowl found among the contents of the barrel be the remains of a VHS video cassette? A positive answer to the question was obtained through a combination of optical microscopy, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and Energy Dispersive Spectroscopy (EDS).

  16. Design of Web Questionnaires : A Test for Number of Items per Screen

    NARCIS (Netherlands)

    Toepoel, V.; Das, J.W.M.; van Soest, A.H.O.

    2005-01-01

    This paper presents results from an experimental manipulation of one versus multiple-items per screen format in a Web survey.The purpose of the experiment was to find out if a questionnaire s format influences how respondents provide answers in online questionnaires and if this is depending on

  17. Spatio-temporal risk factors for viral haemorrhagic septicaemia (VHS) in Danish aquaculture

    DEFF Research Database (Denmark)

    Jensen, Ann Britt Bang; Ersbøll, Annette Kjær; Korsholm, Henrik

    2014-01-01

    Viral haemorrhagic septicaemia (VHS) is an economically very important fish disease in the northern hemisphere. When the VHS virus was first isolated in Denmark 50 yr ago, more than 80% of the 800 Danish fish farms were considered to be infected, but vigilant surveillance and eradication programmes...

  18. Generalization of the Lord-Wingersky Algorithm to Computing the Distribution of Summed Test Scores Based on Real-Number Item Scores

    Science.gov (United States)

    Kim, Seonghoon

    2013-01-01

    With known item response theory (IRT) item parameters, Lord and Wingersky provided a recursive algorithm for computing the conditional frequency distribution of number-correct test scores, given proficiency. This article presents a generalized algorithm for computing the conditional distribution of summed test scores involving real-number item…

  19. VHS domains of ESCRT-0 cooperate in high-avidity binding to polyubiquitinated cargo

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Xuefeng; Hurley, James H. (NIH)

    2010-03-30

    VHS (Vps27, Hrs, and STAM) domains occur in ESCRT-0 subunits Hrs and STAM, GGA adapters, and other trafficking proteins. The structure of the STAM VHS domain-ubiquitin complex was solved at 2.6 {angstrom} resolution, revealing that determinants for ubiquitin recognition are conserved in nearly all VHS domains. VHS domains from all classes of VHS-domain containing proteins in yeast and humans, including both subunits of ESCRT-0, bound ubiquitin in vitro. ESCRTs have been implicated in the sorting of Lys63-linked polyubiquitinated cargo. Intact human ESCRT-0 binds Lys63-linked tetraubiquitin 50-fold more tightly than monoubiquitin, though only 2-fold more tightly than Lys48-linked tetraubiquitin. The gain in affinity is attributed to the cooperation of flexibly connected VHS and UIM motifs of ESCRT-0 in avid binding to the polyubiquitin chain. Mutational analysis of all the five ubiquitin-binding sites in yeast ESCRT-0 shows that cooperation between them is required for the sorting of the Lys63-linked polyubiquitinated cargo Cps1 to the vacuole.

  20. 9 CFR 93.911 - Ports designated for the importation of live VHS-regulated fish species.

    Science.gov (United States)

    2010-01-01

    ... of live VHS-regulated fish species. 93.911 Section 93.911 Animals and Animal Products ANIMAL AND... (INCLUDING POULTRY) AND ANIMAL PRODUCTS IMPORTATION OF CERTAIN ANIMALS, BIRDS, FISH, AND POULTRY, AND CERTAIN... Animal Species General Provisions for Vhs-Regulated Fish Species § 93.911 Ports designated for the...

  1. Paternal Association of Increased Susceptibility to Viral Haemorrhagic Septicaemia (VHS) in Rainbow Trout (Oncorhynchus mykiss)

    DEFF Research Database (Denmark)

    Kaastrup, P.; Hørlyck, Viggo; Olesen, Niels Jørgen

    1991-01-01

    trout has been started in Denmark. This programme will be based on experimental VHS challenge of the parental fish (n = 84) as well as their normal and gynogenetic offspring (16 fullsib F1 groups). We found a paternal influence on the average VHS resistance of the offspring; partial regression...... coefficients for sire-offspring were estimated at 0.30 ± 0.09 and for dam-offspring at −0.1 ± 0.12....

  2. First isolation and genotyping of viruses from recent outbreaks of viral haemorrhagic septicaemia (VHS) in Slovenia

    DEFF Research Database (Denmark)

    Toplak, Ivan; Hostnik, Peter; Rihtaric, Danijela

    2010-01-01

    In November and December 2007, the virus causing viral haemorrhagic septicaemia (VHS) was detected in rainbow trout Oncorhynchus mykiss from 2 fish farms in Slovenia. During 2008 and 2009 the infection spread only among rainbow trout farms and 4 new outbreaks were confirmed. High mortality and cl...

  3. Radiographic evaluation of the cardiac silluet using the VHS method (Vertebral Heart Size in young and adults coatis (Nasua nasua, Linneaus 1766 living in captivity

    Directory of Open Access Journals (Sweden)

    Andresa Cássia Martini

    2014-02-01

    Full Text Available Radiographic examination of the toracic cavity is an usefull noninvasive method for assessment, monitoring the progress of heart disease, suggesting prognosis and guiding the treatment. The aim of this study was to evaluate the cardiac silhouette of young and adults coatis and evaluate its relationship to the number of thoracic vertebrae (VHS, the method proposed by Buchanam and Buchele (1995 for small animals. We evaluated a group of 20 coatis, divided by age: I (GI and 8 animals aged between 4 and 5 months and group II (GII with 12 animals over 12 months old. Based in chest radiographs and VD laterolateral right projections for determining the major axis (L and short axis (Y being the sum of L and S is the value obtained by ESR, the relative depth/width (D / L chest were obtained and the results determined the type of conformation of the thorax, which results greater than 1.25 cm denote chest type deep, 0.75 to 1.25 cm chest intermediate and inferior results will 0.75cm wide chest. It was observed that the heart is alocated between the fourth and seventh pair of ribs, VHS average coatis healthy adults was 9.36 ± 0.75 and 8.06 ± 0 youth, 595 units thoracic vertebrae and the predominant conformation found was of intermediate type when compared to dogs. The mean values in this study serve as a basis for interpretation of the VHS type, however, a larger number may be required animals to determine the physiological limits of the cardiac silhouette in coati.

  4. Increasing the Number of Replications in Item Response Theory Simulations: Automation through SAS and Disk Operating System

    Science.gov (United States)

    Gagne, Phill; Furlow, Carolyn; Ross, Terris

    2009-01-01

    In item response theory (IRT) simulation research, it is often necessary to use one software package for data generation and a second software package to conduct the IRT analysis. Because this can substantially slow down the simulation process, it is sometimes offered as a justification for using very few replications. This article provides…

  5. FI-FG: Frequent Item Sets Mining from Datasets with High Number of Transactions by Granular Computing and Fuzzy Set Theory

    OpenAIRE

    Zhong-jie Zhang; Jian Huang; Ying Wei

    2015-01-01

    Mining frequent item set (FI) is an important issue in data mining. Considering the limitations of those exact algorithms and sampling methods, a novel FI mining algorithm based on granular computing and fuzzy set theory (FI-GF) is proposed, which mines those datasets with high number of transactions more efficiently. Firstly, the granularity is applied, which compresses the transactions to some granules for reducing the scanning cost. During the granularity, each granule is represented by a ...

  6. Using generalizability theory to estimate the relative effect of class size and number of items on the dependability of student ratings of instruction.

    Science.gov (United States)

    Ibrahim, Ali Mohamed

    2011-08-01

    Previous research on the effect of class size on student ratings of instruction has primarily investigated the effect of class size on the favorableness of these ratings rather than its effect on their reliability (dependability). A few studies have used "generalizability theory" to demonstrate the relative effect of class size on the dependability of student ratings of instruction. The purpose of the present study was to test the validity of the findings of these studies in a different cultural setting using a different student ratings questionnaire. Using a random-effect analysis of variance to estimate the variance components for a design in which students were nested within classes and crossed with items, it was found that the variance component for class size was appreciably larger than that for items. At least 20 students were needed to obtain a generalizability coefficient for relative decisions of .70 or more. Increasing the number of students has a greater effect on generalizability coefficients than increasing the number of items.

  7. Interference of an ERM-vaccine with a VHS-DNA vaccine in rainbow trout

    DEFF Research Database (Denmark)

    Lorenzen, Ellen; Einer-Jensen, Katja; Rasmussen, Jesper Skou

    results showed that intraperitoneal injection of a commercial vaccine against Enteric Redmouth Disease (ERM) based on formalin-killed bacteria in oil adjuvant immediately followed by intramuscular injection of an experimental DNA-vaccine against VHSV, decreased the protective effect of the DNA...... are vaccinated with a VHS-DNA vaccine dose according to their size, a simultaneous intraperitoneal vaccination against ERM can compromise the protective effect of the DNA-vaccine. The negative effect appears to be strongest in the early phase following vaccination. The immune mechanisms behind this interference...

  8. Immunity to viral haemorrhagic septicaemia (VHS) following DNA vaccination of rainbow trout at an early life-stage

    DEFF Research Database (Denmark)

    Lorenzen, Niels; Lorenzen, Ellen; Einer-Jensen, Katja

    2001-01-01

    Rainbow trout fry of average weight 0.5 g were vaccinated against viral haemorrhagic septicaemia (VHS) by intramuscular injection of 1 mug of plasmid DNA encoding the VHS virus glycoprotein gene. Challenge with a lethal dose of virus at two different time points, 9 and 71 days post-vaccination...... respectively, revealed that a highly protective and lasting immunity was established shortly after vaccination, in accordance with earlier experiments with larger fish. The defence mechanisms activated by the DNA vaccine are thus functional at an early life-stage in rainbow trout....

  9. Brain activity is related to individual differences in the number of items stored in auditory short-term memory for pitch: evidence from magnetoencephalography.

    Science.gov (United States)

    Grimault, Stephan; Nolden, Sophie; Lefebvre, Christine; Vachon, François; Hyde, Krista; Peretz, Isabelle; Zatorre, Robert; Robitaille, Nicolas; Jolicoeur, Pierre

    2014-07-01

    We used magnetoencephalography (MEG) to examine brain activity related to the maintenance of non-verbal pitch information in auditory short-term memory (ASTM). We focused on brain activity that increased with the number of items effectively held in memory by the participants during the retention interval of an auditory memory task. We used very simple acoustic materials (i.e., pure tones that varied in pitch) that minimized activation from non-ASTM related systems. MEG revealed neural activity in frontal, temporal, and parietal cortices that increased with a greater number of items effectively held in memory by the participants during the maintenance of pitch representations in ASTM. The present results reinforce the functional role of frontal and temporal cortices in the retention of pitch information in ASTM. This is the first MEG study to provide both fine spatial localization and temporal resolution on the neural mechanisms of non-verbal ASTM for pitch in relation to individual differences in the capacity of ASTM. This research contributes to a comprehensive understanding of the mechanisms mediating the representation and maintenance of basic non-verbal auditory features in the human brain. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Item Banking.

    Science.gov (United States)

    Rudner, Lawrence

    1999-01-01

    Discusses the advantages and disadvantages of using item banks while providing useful information to those who are considering implementing an item banking project in their school district. The primary advantage of item banking is in test development. Also describes start-up activities in implementing item banking. (SLD)

  11. FI-FG: Frequent Item Sets Mining from Datasets with High Number of Transactions by Granular Computing and Fuzzy Set Theory

    Directory of Open Access Journals (Sweden)

    Zhong-jie Zhang

    2015-01-01

    Full Text Available Mining frequent item set (FI is an important issue in data mining. Considering the limitations of those exact algorithms and sampling methods, a novel FI mining algorithm based on granular computing and fuzzy set theory (FI-GF is proposed, which mines those datasets with high number of transactions more efficiently. Firstly, the granularity is applied, which compresses the transactions to some granules for reducing the scanning cost. During the granularity, each granule is represented by a fuzzy set, and the transaction scale represented by a granule is optimized. Then, fuzzy set theory is used to compute the supports of item sets based on those granules, which faces the uncertainty brought by the granularity and ensures the accuracy of the final results. Finally, Apriori is applied to get the FIs based on those granules and the new computing way of supports. Through five datasets, FI-GF is compared with the original Apriori to prove its reliability and efficiency and is compared with a representative progressive sampling way, RC-SS, to prove the advantage of the granularity to the sampling method. Results show that FI-GF not only successfully saves the time cost by scanning transactions but also has the high reliability. Meanwhile, the granularity has advantages to those progressive sampling methods.

  12. Can VHS virus bypass the protective immunity induced by DNA vaccination in rainbow trout?

    DEFF Research Database (Denmark)

    Sepúlveda, Dagoberto; Lorenzen, Niels

    2016-01-01

    DNA vaccines encoding viral glycoproteins have been very successful for induction of protective immunity against diseases caused by rhabdoviruses in cultured fish species. However, the vaccine concept is based on a single viral gene and since RNA viruses are known to possess high variability...... and adaptation capacity, this work aimed at evaluating whether viral haemorrhagic septicaemia virus (VHSV), an RNA virus and member of Rhabdoviridae family, was able to evade the protective immune response induced by the DNA vaccination of rainbow trout. The experiments comprised repeated passages of a highly...... pathogenic VHSV isolate in a fish cell line in the presence of neutralizing fish serum (in vitro approach), and in rainbow trout immunized with the VHS DNA vaccine (in vivo approach). For the in vitro approach, the virus collected from the last passage (passaged virus) was as sensitive as the parental virus...

  13. Mensuração do tamanho cardíaco pelo método VHS (vertebral heart size em cães sadios da raça American pit bull terrier Measurement of heart size by VHS (vertebral heart size method in healthy American pit bull terrier

    Directory of Open Access Journals (Sweden)

    Mauro José Lahm Cardoso

    2011-01-01

    Full Text Available Vários métodos surgiram com a finalidade de aumentar a acurácia e diminuir a subjetividade na avaliação das radiografias. O melhor aceito é o VHS (vertebral heart size, ou tamanho do coração em relação à unidade de vértebra torácica. O objetivo deste trabalho foi aplicar o método de mensuração pelo VHS em cães da raça American pit bull terrier clinicamente sadios, com a finalidade de se estabelecer o valor médio de VHS para esta raça. Realizaram-se radiografias de tórax, na projeção lateral direita, que foram avaliadas empiricamente e realizadas as medidas necessárias para obtenção do VHS, além da obtenção da relação profundidade/largura (P/L torácica. Nenhum animal apresentou alteração através da análise empírica. Os valores de VHS obtidos apresentaram distribuição normal, assim como a relação P/L, com média de 10,9±0,4 vértebras para o VHS e 0,80±0,07 para a relação P/L. O valor do VHS apresentou diferença significativa (P>0,05 em comparação com os resultados obtidos por BUCHANAN & BÜCHELER (1995. Porém, o valor de VHS deste estudo é semelhante ao descrito por diversos autores nos estudo de raças específicas, confirmando a necessidade de se estabelecer valores de VHS específicos para cada raça.In order to increase accuracy and reduce the subjectivity in the evaluation of radiographies, several methods have emerged. The most accepted of these methods is the Vertebral Heart Size method (VHS, or the heart's size versus the thoracic vertebra's unit. The intention of this research was to apply the VHS measurement method in clinically healthy American pit bull terrier, with the purpose of establishing the average VHS for this breed. Chest x-rays in lateral projection were taken, and these were empirically evaluated and measured so that a VHS value was obtained, as well as the thoracic depth/width (D/W relation for each animal. None of the animals had abnormal results when evaluated via empiric

  14. FI-FG: Frequent Item Sets Mining from Datasets with High Number of Transactions by Granular Computing and Fuzzy Set Theory

    National Research Council Canada - National Science Library

    Zhang, Zhong-jie; Huang, Jian; Wei, Ying

    2015-01-01

      Mining frequent item set (FI) is an important issue in data mining. Considering the limitations of those exact algorithms and sampling methods, a novel FI mining algorithm based on granular computing and fuzzy set theory (FI-GF...

  15. Computerized adaptive testing with item cloning

    NARCIS (Netherlands)

    Glas, Cornelis A.W.; van der Linden, Willem J.

    2003-01-01

    To increase the number of items available for adaptive testing and reduce the cost of item writing, the use of techniques of item cloning has been proposed. An important consequence of item cloning is possible variability between the item parameters. To deal with this variability, a multilevel item

  16. Bipolar Items

    Directory of Open Access Journals (Sweden)

    Nishiguchi Sumiyo

    2016-12-01

    Full Text Available This article asserts that the Japanese wide-scope mo ‘even’ in simple sentences are bipolar items (BPIs antilicensed or forbidden by negation and licensed in a non-monotonic (NM environment. BPIs share the features of negative polarity items (NPIs as well as positive polarity items (PPIs. The Dutch ooit ‘ever’, the Serbo-Croatian i-series ‘and/even’, and the Hungarian is-series ‘and/even’ are antilicensed by clausemate negation and licensed by extraclausal negation (van der Wouden, 1997; Progovac, 1994; Szabolcsi, 2002 or non-monotonic negative (and positive, for Serbo-Croatian emotive predicates. Adding an NPI rescues BPIs in uncomfortable clausemate negation.

  17. Application of screening tools to detect risk of hospital readmission in elderly patients in Valencian Healthcare System (VHS) (Spain).

    Science.gov (United States)

    Doñate-Martínez, Ascensión; Garcés Ferrer, Jorge; Ródenas Rigla, Francisco

    2014-01-01

    The Sustainable Social and Healthcare Model (SSHM) is aimed to establish new care pathways in primary care systems contributing to the decrease of health services use and costs and improve the integration and efficiency of social and health care for elderly people with long-term care (LTC) needs. One of these strategies is the segmentation of population in risk groups through standardized tools. This paper is a retrospective study aimed to determine the viability of the implementation of the screening tools Probability of Repeated Admission - Pra - and The Community Assessment Risk Screen - CARS - to detect patients at risk of hospital readmission in a sample of 500 elderly people (65+) from the VHS in Spain. Patients were recruited from three Health Departments. Data from selected tools and predictive variables were collected through the healthcare database from the VHS. The most important results indicate that both instruments predict with high efficacy the proportion of patients not readmitted (negative predictive value between 91% and 92%). Moreover, the tools performed with a moderate efficiency being the Pra less sensitive (54%) and more specific (81%) than CARS (with a sensitivity and specificity of 64%). Results from this study suggest that the application of instruments as Pra and CARS are of interest to the Valencian Health Administration as they can be a good strategy to improve the management of elderly patients at risk with comorbidities and guiding clinical decision. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  18. Item Overexposure in Computerized Classification Tests Using Sequential Item Selection

    Directory of Open Access Journals (Sweden)

    Alan Huebner

    2012-06-01

    Full Text Available Computerized classification tests (CCTs often use sequential item selection which administers items according to maximizing psychometric information at a cut point demarcating passing and failing scores. This paper illustrates why this method of item selection leads to the overexposure of a significant number of items, and the performances of three different methods for controlling maximum item exposure rates in CCTs are compared. Specifically, the Sympson-Hetter, restricted, and item eligibility methods are examined in two studies realistically simulating different types of CCTs and are evaluated based upon criteria including classification accuracy, the number of items exceeding the desired maximum exposure rate, and test overlap. The pros and cons of each method are discussed from a practical perspective.

  19. The Causality Study of External Environment Analysis (EEA), Internal Environment Analysis (IEA), Strategy Implementation on Study Program Performance at Vocational High School (VHS) in Nias Archipelago, Indonesia

    Science.gov (United States)

    Waruwu, Binahati; Sitompul, Harun; Manullang, Belferik

    2016-01-01

    The purposes of this study are to find out the significant effect of: (1) EEA on strategy implementation, (2) IEA on strategy implementation, (3) EEA on study program performance, (4) IEA on study program performance, and (5) strategy implementation on study program performance of Vocational High School (VHS) in Nias Archipelago. The population of…

  20. Cardiothoracic ratio and vertebral heart size (VHS to standardize the heart size of the tufted capuchin (Cebus apella Linnaeus, 1758 in computerized radiographic images

    Directory of Open Access Journals (Sweden)

    Hermínio J. Rocha-Neto

    2015-10-01

    Full Text Available Abstract: The VHS and CTR were assessed using computerized thoracic radiographs of ten clinically healthy tufted capuchin monkeys (five males and five females from the Wild Animal Screening Center in São Luís (Centro de Triagem de Animais Silvestres de São Luís-MA-CETAS. Radiographs were taken in laterolateral and dorsoventral projections to calculate the cardiothoracic ratio (VHS and vertebral heart size (CTR. The VHS showed mean values of 9.34±0.32v (males and 9.16±0.34v (females and there was no statistical difference between males and females (p>0.05. The CTR showed mean values of 0.55±0.04 (males and 0.52±0.03 (females and there was no statistical difference between the sexes (p>0.05. There was positive correlation between VHS and CTR (r=0.78. The thoracic and heart diameters showed mean values of 5.70±0.48cm and 2.16±0.40cm in the males, respectively. In the females they measured 5.32±0.39cm and 2.94±0.32cm. There was no statistical difference between the sexes. Our results show that the high correlation found between VHS and CTR permitted the verification with similar clinical precision between the two methods to estimate alterations in the heart silhouette by radiographic examination of tufted capuchin, making it an easy technique to apply that can be considered in the investigation of heart problems for this wild species.

  1. 48 CFR 252.211-7003 - Item identification and valuation.

    Science.gov (United States)

    2010-10-01

    ... to a class of items with the same form, fit, function, and interface. Parent item means the item..., and parts embedded within delivered items as specified in Attachment Number __. (2) The unique item... item identifier is used). (10) Government's unit acquisition cost. (11) Unit of measure. (e) For...

  2. Inactivated vaccine against viral hemorrhagic septicemia (VHS) emulsified with squalene and aluminum hydroxide adjuvant provides long term protection in olive flounder (Paralichthys olivaceus).

    Science.gov (United States)

    Vinay, Tharabenahalli-Nagaraju; Kim, Ye-Ji; Jung, Myung-Hwa; Kim, Wi-Sik; Kim, Do-Hyung; Jung, Sung-Ju

    2013-09-23

    Viral hemorrhagic septicemia (VHS) in olive flounder (Paralichthys olivaceus) remains an unsolved health problem in Korean aquaculture. Vaccination plays a significant role in modern aquaculture, and the duration of protection provided is of vital importance. Here, we have demonstrated the efficacy, duration of protection and safety of an inactivated vaccine emulsified with squalene (5%) and aluminum hydroxide (0.5%). The inactivated VHS vaccine provided a moderate protection of 37% and 47% relative percent survival (RPS) at 4 and 10 weeks post vaccination (wpv). Addition of squalene and aluminum hydroxide into inactivated VHS vaccine clearly enhanced the level of protection showing 58% and 83% RPS at 4 and 10 wpv, respectively, indicating the need for adjuvants to enhance the efficacy. The vaccinated fish showed significant protection at 3, 6, 12, 18, 24, and 40 wpv (except week 57) than non-vaccinated fish to an intraperitoneal challenge of 10(7.1)TCID₅₀/fish at 15 °C, with RPS of 60%, 64%, 71%, 55%, 52% and 50% (45% at 57 week), respectively, covering the duration of natural outbreak. Fish challenged at 18 wpv at 6 °C showed 56% RPS and protection at a low temperature. The antibody titer was high at 3 wpv with an OD of 1.08 ± 0.13, but decreased gradually and was undetectable by 24 wpv. The vaccine formulation was safe without injection site reactions, adhesions, or pigmentation observed at 6, 12, 18, or 24 wpv. Inflammatory reactions were observed in the spleen intestine at 6 and 12 wpv but were similar as control by 24 wpv. These results confirm that this vaccine is efficient and safe for olive flounder and could offer an appropriate strategy to prevent VHS without causing side effects. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Dental Items of Significance, Number 42

    Science.gov (United States)

    1994-05-01

    Interocclusal record Is made with the mandible in a protrusive end-to-end Incisal relationship, opened 8 to 10 mm vertically. S 2. On maxillary and mandibular ...maxillary Impression tray. Once the material has been molded to the maxillary arch, it maintains Its shape. The mandibular portion is then formed by...softening and adjusting a ramp for the mandibular anterior teeth to rest against. Source: Dental Sleep Disorder Prevention, Inc. P.O. Box 21623 Albuquerque

  4. DNA vaccination against viral haemorrhagic septicaemia (VHS) in rainbow trout: size, dose, route of injection and duration of protection-early protection correlates with Mx expression

    DEFF Research Database (Denmark)

    McLauchlan, P.E.; Collet, B.; Ingerslev, Esben

    2003-01-01

    , or with inactivated VHS virus. Fish were challenged at different times post-vaccination (p.v.) to assess protection. At certain times p.v., serum samples were analysed for neutralising antibody and liver tissue was analysed for Mx mRNA expression.A DNA dose of 0.5 mug injected by the i.m. route induced protection......Rainbow trout of different sizes (10 and 100 g) were injected intramuscularly (i.m.) or intraperitoneally (i.p.) with different doses (range 10ng-10mug) of a viral haemorrhagic septicaemia (VHS)-DNA vaccine (pcDNA3vhsG). As controls, fish were injected with the pcDNA3 plasmid alone....... Vaccination by the i.p. route induced no or lower levels of protection compared with the i.m. route.Fish vaccinated with 0.5 mug DNA i.m. had no detectable serum neutralising antibody (NAb) at 4 weeks p.v. (with the exception of a single 10 g fish) but antibody was detected at 8 weeks and 6 months p...

  5. Índices baseados no número de clientes para localização de itens em armazéns Indexes based on the number of customers to locate items in warehouse

    Directory of Open Access Journals (Sweden)

    Marcele Elisa Fontana

    2013-01-01

    Full Text Available Para se obter eficiência nas operações de armazenagem, um fator importante é estabelecer a política ótima de atribuição da localização dos itens em armazéns. Para tanto, um dos índices mais difundidos e utilizados é o cuber-per-order (COI. No entanto, observa-se que há situações em que o uso do COI pode concentrar vantagens para uma minoria de clientes. Nesse sentido, este artigo propõe verificar as consequências da utilização de índices alternativos (COIC e CIC, baseados no número de clientes que demandam cada tipo de produto (item, sobre o desempenho de um armazém em relação à utilização do COI. Conclui-se que considerar o número de clientes na determinação da política ótima de atribuição de locais aos itens armazenados proporciona uma maior vantagem competitiva, uma vez que um número maior de clientes pode ser beneficiado. Isso representa uma oportunidade de elevar o nível de serviço oferecido pelo armazém aos clientes.An important factor to obtain efficiency of storage operations is to establish an optimal policy for storage location assignment. To this end, one of the indexes more circulated and used is the Cuber-per-Order (COI. However, it is observed that there are situations where the use of COI can concentrate advantages to a minority of clients. In this sense, this paper proposes to verify the effects on the performance of a warehouse when using alternative indexes (COIC and CIC, based on the number of clients that require each type of product (item, compared to the COI. It was possible to conclude that when the number of clients is considered to determine optimal policy for storage location assignment, the warehouse can acquire a competitive advantage, since the largest number of clients can be benefited. This represents an opportunity to raise the service level offered by the warehouse to its clients.

  6. Automated Item Selection Using Item Response Theory.

    Science.gov (United States)

    Stocking, Martha L.; And Others

    This paper presents a new heuristic approach to interactive test assembly that is called the successive item replacement algorithm. This approach builds on the work of W. J. van der Linden (1987) and W. J. van der Linden and E. Boekkooi-Timminga (1989) in which methods of mathematical optimization are combined with item response theory to…

  7. Immunohistochemical detection of VHS virus in paraffin-embedded specimens of rainbow trout (Oncorhynchus mykiss); The influence of primary antibody, fixative, and antigen unmasking on method sensitivity

    DEFF Research Database (Denmark)

    Evensen, O.; Olesen, Niels Jørgen

    1997-01-01

    The influence of the primary antibody, the fixative, and the antigen unmasking technique on the method sensitivity of immunohistochemistry as a method for the identification of viral hemorrhagic septicemia (VHS) virus in paraffin-embedded specimens of naturally infected rainbow trout (Oncorhynchus...... performed on parallel specimens, and the virus titer (TCID50/ml) was determined. Purified nucleocapsid protein (N-protein) of the virus was incorporated in an artificial antigen substrate (polymerized bovine serum albumin), fixed as described above, and embedded in paraffin wax. Microwave unmasking...

  8. NHRIC (National Health Related Items Code)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The National Health Related Items Code (NHRIC) is a system for identification and numbering of marketed device packages that is compatible with other numbering...

  9. Elaborate Item Count Questioning: Why Do People Underreport in Item Count Responses?

    Directory of Open Access Journals (Sweden)

    Takahiro Tsuchiya

    2010-12-01

    Full Text Available The item count technique, used often to investigate illegal or socially undesirable behaviours, requires respondents to indicate merely the number of applicable items from among a list. However, the number of applicable items indicated via the item count question tends to be smaller than when it is calculated from the direct `applies/does not apply' responses to each item. Because this inconsistency, which we refer to as the underreporting effect, often disturbs proper item count estimates, the causes of this effect are explored in this paper. Web survey results revealed that the order of the response alternatives is irrelevant to the underreporting effect, and that the underreporting effect is caused by the response format in which the item count question requests merely the number of applicable items and not the number of non-applicable items. It is also shown that the magnitude of the underreporting effect decreases when the respondents are asked to indicate the numbers of both applicable and non-applicable items, which we refer to as elaborate item count questioning.

  10. A Comparison of Anchor-Item Designs for the Concurrent Calibration of Large Banks of Likert-Type Items

    Science.gov (United States)

    Garcia-Perez, Miguel A.; Alcala-Quintana, Rocio; Garcia-Cueto, Eduardo

    2010-01-01

    Current interest in measuring quality of life is generating interest in the construction of computerized adaptive tests (CATs) with Likert-type items. Calibration of an item bank for use in CAT requires collecting responses to a large number of candidate items. However, the number is usually too large to administer to each subject in the…

  11. Modeling variability in item parameters in item response models

    NARCIS (Netherlands)

    Glas, Cornelis A.W.; van der Linden, Willem J.

    2001-01-01

    In some areas of measurement item parameters should not be modeled as fixed but as random. Examples of such areas are: item sampling, computerized item generation, measurement with substantial estimation error in the item parameter estimates, and grouping of items under a common stimulus or in a

  12. SHIPPING OF RADIOACTIVE ITEMS

    CERN Multimedia

    TIS/RP Group

    2001-01-01

    The TIS-RP group informs users that shipping of small radioactive items is normally guaranteed within 24 hours from the time the material is handed in at the TIS-RP service. This time is imposed by the necessary procedures (identification of the radionuclides, determination of dose rate and massive objects require a longer procedure and will therefore take longer.

  13. Acquiring negative polarity items

    NARCIS (Netherlands)

    Lin, J.

    2015-01-01

    Negative Polarity Items (NPIs) are words or expressions that exhibit a restricted distribution to certain negative contexts only. For example, yet is an NPI and must appear in the scope of a negation: Mary has *(not) finished yet. The existence of NPIs such as yet gives rise to a learnability

  14. Investigating an Invariant Item Ordering for Polytomously Scored Items

    Science.gov (United States)

    Ligtvoet, Rudy; van der Ark, L. Andries; te Marvelde, Janneke M.; Sijtsma, Klaas

    2010-01-01

    This article discusses the concept of an invariant item ordering (IIO) for polytomously scored items and proposes methods for investigating an IIO in real test data. Method manifest IIO is proposed for assessing whether item response functions intersect. Coefficient H[superscript T] is defined for polytomously scored items. Given that an IIO…

  15. Comparative Racial Analysis of Enlisted Advancement Exams: Item Differentiation

    Science.gov (United States)

    1977-01-01

    homogeneity may be the types of items that besc contribute to predicting job-relevant performance by an external criterion. Thus, until externa ...the item itself (Nunnally, 1967). (Obviously, the size of this artifact will vary inversely with the number of items in the test/section.) Also, if a

  16. Item response theory - A first approach

    Science.gov (United States)

    Nunes, Sandra; Oliveira, Teresa; Oliveira, Amílcar

    2017-07-01

    The Item Response Theory (IRT) has become one of the most popular scoring frameworks for measurement data, frequently used in computerized adaptive testing, cognitively diagnostic assessment and test equating. According to Andrade et al. (2000), IRT can be defined as a set of mathematical models (Item Response Models - IRM) constructed to represent the probability of an individual giving the right answer to an item of a particular test. The number of Item Responsible Models available to measurement analysis has increased considerably in the last fifteen years due to increasing computer power and due to a demand for accuracy and more meaningful inferences grounded in complex data. The developments in modeling with Item Response Theory were related with developments in estimation theory, most remarkably Bayesian estimation with Markov chain Monte Carlo algorithms (Patz & Junker, 1999). The popularity of Item Response Theory has also implied numerous overviews in books and journals, and many connections between IRT and other statistical estimation procedures, such as factor analysis and structural equation modeling, have been made repeatedly (Van der Lindem & Hambleton, 1997). As stated before the Item Response Theory covers a variety of measurement models, ranging from basic one-dimensional models for dichotomously and polytomously scored items and their multidimensional analogues to models that incorporate information about cognitive sub-processes which influence the overall item response process. The aim of this work is to introduce the main concepts associated with one-dimensional models of Item Response Theory, to specify the logistic models with one, two and three parameters, to discuss some properties of these models and to present the main estimation procedures.

  17. Effects of spacing of item repetitions in continuous recognition memory: does item retrieval difficulty promote item retention in older adults?

    Science.gov (United States)

    Kılıç, Aslı; Hoyer, William J; Howard, Marc W

    2013-01-01

    BACKGROUND/STUDY CONTEXT: Older adults exhibit an age-related deficit in item memory as a function of the length of the retention interval, but older adults and young adults usually show roughly equivalent benefits due to the spacing of item repetitions in continuous memory tasks. The current experiment investigates the seemingly paradoxical effects of retention interval and spacing in young and older adults using a continuous recognition memory procedure. Fifty young adults and 52 older adults gave memory confidence ratings to words that were presented once (P1), twice (P2), or three times (P3), and the effects of the lag length and retention interval were assessed at P2 and at P3, respectively. Response times at P2 were disproportionately longer for older adults than for younger adults as a function of the number of items occurring between P1 and P2, suggestive of age-related loss in item memory. Ratings of confidence in memory responses revealed that older adults remembered fewer items at P2 with a high degree of certainty. Confidence ratings given at P3 suggested that young and older adults derived equivalent benefits from the spacing between P1 and P2. Findings of this study support theoretical accounts that suggest that recursive reminding and/or item retrieval difficulty promote item retention in older adults.

  18. Item Banking with Embedded Standards

    Science.gov (United States)

    MacCann, Robert G.; Stanley, Gordon

    2009-01-01

    An item banking method that does not use Item Response Theory (IRT) is described. This method provides a comparable grading system across schools that would be suitable for low-stakes testing. It uses the Angoff standard-setting method to obtain item ratings that are stored with each item. An example of such a grading system is given, showing how…

  19. Item Pool Design for an Operational Variable-Length Computerized Adaptive Test

    Science.gov (United States)

    He, Wei; Reckase, Mark D.

    2014-01-01

    For computerized adaptive tests (CATs) to work well, they must have an item pool with sufficient numbers of good quality items. Many researchers have pointed out that, in developing item pools for CATs, not only is the item pool size important but also the distribution of item parameters and practical considerations such as content distribution…

  20. Student-constructed examination items.

    Science.gov (United States)

    Hoffman, K I; Solinas, J; Marshall, G J

    1978-01-01

    Student-written items were compared with teacher-written items on an objective examination given to first year medical students. While student scores were higher on the student-written items than on teacher-written items, there was a positive correlation between the scores. Student items did not differ from teacher items in the course, according to student ratings of emphasis. As a by-product of this study, correlations were found which suggest that student scores on an item often reflect the degree of teaching emphasis given the content area of the item rather than the inherent difficulty of the content. It is suggested that further research is needed to determine whether students learn through the process of writing examination items. Therefore, if the process proves to be educational, this study indicates that it will be feasible to incorporate the student-constructed items in examinations.

  1. SHIPPING OF RADIOACTIVE ITEMS

    CERN Document Server

    TIS/RP Group

    2001-01-01

    The TIS-RP group informs users that shipping of small radioactive items is normally guaranteed within 24 hours from the time the material is handed in at the TIS-RP service. This time is imposed by the necessary procedures (identification of the radionuclides, determination of dose rate, preparation of the package and related paperwork). Large and massive objects require a longer procedure and will therefore take longer.

  2. Real and Artificial Differential Item Functioning in Polytomous Items

    Science.gov (United States)

    Andrich, David; Hagquist, Curt

    2015-01-01

    Differential item functioning (DIF) for an item between two groups is present if, for the same person location on a variable, persons from different groups have different expected values for their responses. Applying only to dichotomously scored items in the popular Mantel-Haenszel (MH) method for detecting DIF in which persons are classified by…

  3. Examining the Impact of Drifted Polytomous Anchor Items on Test Characteristic Curve (TCC) Linking and IRT True Score Equating. Research Report. ETS RR-12-09

    Science.gov (United States)

    Li, Yanmei

    2012-01-01

    In a common-item (anchor) equating design, the common items should be evaluated for item parameter drift. Drifted items are often removed. For a test that contains mostly dichotomous items and only a small number of polytomous items, removing some drifted polytomous anchor items may result in anchor sets that no longer resemble mini-versions of…

  4. An EPQ model with imperfect items using interval grey numbers

    OpenAIRE

    Erdal Aydemir; Fevzi Bedir; Gultekin Ozdemir; Abdullah Eroglu

    2015-01-01

    The classic economic production quantity (EPQ) model has been widely used to determine the optimal production quantity. However, the analysis for finding an EPQ model has many weaknesses which lead many researchers and practitioners to make extensions in several aspects on the original EPQ model. The basic assumption of EPQ model is that 100% of manufactured products are non-defective that is not valid for many production processes generally. The purpose of this paper is to develop an EPQ...

  5. Problems with the factor analysis of items: Solutions based on item response theory and item parcelling

    Directory of Open Access Journals (Sweden)

    Gideon P. De Bruin

    2004-10-01

    Full Text Available The factor analysis of items often produces spurious results in the sense that unidimensional scales appear multidimensional. This may be ascribed to failure in meeting the assumptions of linearity and normality on which factor analysis is based. Item response theory is explicitly designed for the modelling of the non-linear relations between ordinal variables and provides a strong alternative to the factor analysis of items. Items may also be combined in parcels that are more likely to satisfy the assumptions of factor analysis than do the items. The use of the Rasch rating scale model and the factor analysis of parcels is illustrated with data obtained with the Locus of Control Inventory. The results of these analyses are compared with the results obtained through the factor analysis of items. It is shown that the Rasch rating scale model and the factoring of parcels produce superior results to the factor analysis of items. Recommendations for the analysis of scales are made. Opsomming Die faktorontleding van items lewer dikwels misleidende resultate op, veral in die opsig dat eendimensionele skale as meerdimensioneel voorkom. Hierdie resultate kan dikwels daaraan toegeskryf word dat daar nie aan die aannames van lineariteit en normaliteit waarop faktorontleding berus, voldoen word nie. Itemresponsteorie, wat eksplisiet vir die modellering van die nie-liniêre verbande tussen ordinale items ontwerp is, bied ’n aantreklike alternatief vir die faktorontleding van items. Items kan ook in pakkies gegroepeer word wat meer waarskynlik aan die aannames van faktorontleding voldoen as individuele items. Die gebruik van die Rasch beoordelingskaalmodel en die faktorontleding van pakkies word aan die hand van data wat met die Lokus van Beheervraelys verkry is, gedemonstreer. Die resultate van hierdie ontledings word vergelyk met die resultate wat deur ‘n faktorontleding van die individuele items verkry is. Die resultate dui daarop dat die Rasch

  6. Sex differences in guessing and item omission

    Directory of Open Access Journals (Sweden)

    Karolina Świst

    2015-09-01

    Full Text Available Guessing and item omission may be regarded as risk-taking or risk-avoidance strategies – sex specific adaptations to testing situations. In this article, these phenomena were analysed by (a percentage of omissions by sex, (b negative binomial regression to asses sex differences in the number of omissions, (c c-DIF analysis using IRT-LR test and (d linear regression using item attributes, to assess whether the c-parameter is sex differentiated by the percentage of omits (controlling item difficulty. The data set analysed were from the 2012–2014 Polish lower-secondary schools final exams, comprising tests in maths, language, science and humanities. Contrary to the vast body of literature, boys omitted items slightly more frequently than girls. Possible explanations of this finding – specific to the Polish examination system – were provided. The hypothesis of a higher c-parameter for boys did not find strong support from this study. It was shown that the c-parameter should not only be interpreted as resulting from item non-omission. This supports the modern concept of the c-parameter as a consequence not only of random guessing, but also problem solving, creative guessing or cheating.

  7. Verification of Item Usage Rules in Product Configuration

    OpenAIRE

    Voronov, Alexey; Tidstam, Anna; Åkesson, Knut; MALMQVIST, Johan

    2012-01-01

    Part 2: PLM Ecosystem; International audience; In the development of complex products product configuration systems are often used to support the development process. Item Usage Rules (IURs) are conditions for including specific items in products bills of materials based on a high-level product description. Large number of items and significant complexity of IURs make it difficult to maintain and analyze IURs manually. In this paper we present an automated approach for verifying IURs, which g...

  8. Analysis of Item Difficulty Parameters on Item Characteristic Curves ...

    African Journals Online (AJOL)

    The results showed a significant difference between the difficulty levels of test items in WAEC and NECO mathematics objective test instruments, with NECO having more difficulty level in their instruments, as reflected in the item characteristic curves. Thus, the NECO examination mathematics objective test was more difficult ...

  9. Methodology for developing and evaluating the PROMIS smoking item banks.

    Science.gov (United States)

    Hansen, Mark; Cai, Li; Stucky, Brian D; Tucker, Joan S; Shadel, William G; Edelen, Maria Orlando

    2014-09-01

    This article describes the procedures used in the PROMIS Smoking Initiative for the development and evaluation of item banks, short forms (SFs), and computerized adaptive tests (CATs) for the assessment of 6 constructs related to cigarette smoking: nicotine dependence, coping expectancies, emotional and sensory expectancies, health expectancies, psychosocial expectancies, and social motivations for smoking. Analyses were conducted using response data from a large national sample of smokers. Items related to each construct were subjected to extensive item factor analyses and evaluation of differential item functioning (DIF). Final item banks were calibrated, and SF assessments were developed for each construct. The performance of the SFs and the potential use of the item banks for CAT administration were examined through simulation study. Item selection based on dimensionality assessment and DIF analyses produced item banks that were essentially unidimensional in structure and free of bias. Simulation studies demonstrated that the constructs could be accurately measured with a relatively small number of carefully selected items, either through fixed SFs or CAT-based assessment. Illustrative results are presented, and subsequent articles provide detailed discussion of each item bank in turn. The development of the PROMIS smoking item banks provides researchers with new tools for measuring smoking-related constructs. The use of the calibrated item banks and suggested SF assessments will enhance the quality of score estimates, thus advancing smoking research. Moreover, the methods used in the current study, including innovative approaches to item selection and SF construction, may have general relevance to item bank development and evaluation. © The Author 2013. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Description of a food parenting practice item bank

    Science.gov (United States)

    Several recent reviews have highlighted the large number of instruments currently available to assess food parenting practices (FPP). In order to foster development of instruments that assess behaviorally significant FPP domains with appropriate items, an item bank of FPP is being developed, populat...

  11. Detection of differential item functioning using Lagrange multiplier tests

    NARCIS (Netherlands)

    Glas, Cornelis A.W.

    1996-01-01

    In this paper it is shown that differential item functioning can be evaluated using the Lagrange multiplier test or C. R. Rao's efficient score test. The test is presented in the framework of a number of item response theory (IRT) models such as the Rasch model, the one-parameter logistic model, the

  12. Comparison of Polytomous Parametric and Nonparametric Item Response Theory Models

    Directory of Open Access Journals (Sweden)

    Özge BIKMAZ BİLGEN

    2017-12-01

    Full Text Available This research aimed to identify the effects of independent variables as sample size, sample distribution, the number of items in the test, and the number of response categories of items in the test on the estimations of Graded Response Model (GRM under Parametric Item Response Theory (PIRT and by Monotone Homogeneity Model (MHM under Non-Parametric Item Response Theory (NIRT for polytomously scored items. To achieve this aim, the research was performed as a fundamental study in which 192 simulation conditions were designed by the combination of sample size, sample distribution, the number of items, and the number of categories of items. Estimates by GRM and MHM were examined under different levels of sample size (N= 100, 250, 500, 1000, sample distribution (normal, skewed, the number of items (10, 20, 40, 80, and the number of categories of items (3, 5, 7 conditions, by respectively calculating model-data fit, reliability values, standart errors of parameters. As a result of the research, it was found that since the values used to evaluate model-data fit were influenced by the increase of variable while calculating model-data fit and since they can not be interpreted alone, it is difficult to compare and generalize the results. The practical calculation of model data fit, which can be interpreted without the need for another value, in MHM provides superiority over GRM. Another research result is that the reliability values give similar results for both models. The standard errors of the MHM parameter estimates is lower than the GRM estimates under small sample and few items conditions and the standard errors of the MHM parameter estimates are close to each other in all conditions.

  13. Bundle pricing with comparable items

    NARCIS (Netherlands)

    Grigoriev, Alexander; van Loon, Joyce; Sviridenko, Maxim; Uetz, Marc Jochen; Vredeveld, Tjark; Arge, L.; Hoffmann, M.; Welzl, E.

    2007-01-01

    We consider a revenue maximization problem where we are selling a set of items, each available in a certain quantity, to a set of bidders. Each bidder is interested in one or several bundles of items. We assume the bidders’ valuations for each of these bundles to be known. Whenever bundle prices are

  14. A Mixed Effects Randomized Item Response Model

    Science.gov (United States)

    Fox, J.-P.; Wyrick, Cheryl

    2008-01-01

    The randomized response technique ensures that individual item responses, denoted as true item responses, are randomized before observing them and so-called randomized item responses are observed. A relationship is specified between randomized item response data and true item response data. True item response data are modeled with a (non)linear…

  15. Conditional recall and the frequency effect in the serial recall task: an examination of item-to-item associativity.

    Science.gov (United States)

    Miller, Leonie M; Roodenrys, Steven

    2012-11-01

    The frequency effect in short-term serial recall is influenced by the composition of lists. In pure lists, a robust advantage in the recall of high-frequency (HF) words is observed, yet in alternating mixed lists, HF and low-frequency (LF) words are recalled equally well. It has been argued that the preexisting associations between all list items determine a single, global level of supportive activation that assists item recall. Preexisting associations between items are assumed to be a function of language co-occurrence; HF-HF associations are high, LF-LF associations are low, and mixed associations are intermediate in activation strength. This account, however, is based on results when alternating lists with equal numbers of HF and LF words were used. It is possible that directional association between adjacent list items is responsible for the recall patterns reported. In the present experiment, the recall of three forms of mixed lists-those with equal numbers of HF and LF items and pure lists-was examined to test the extent to which item-to-item associations are present in serial recall. Furthermore, conditional probabilities were used to examine more closely the evidence for a contribution, since correct-in-position scoring may mask recall that is dependent on the recall of prior items. The results suggest that an item-to-item effect is clearly present for early but not late list items, and they implicate an additional factor, perhaps the availability of resources at output, in the recall of late list items.

  16. More is not Always Better: The Relation between Item Response and Item Response Time in Raven’s Matrices

    Directory of Open Access Journals (Sweden)

    Frank Goldhammer

    2015-03-01

    Full Text Available The role of response time in completing an item can have very different interpretations. Responding more slowly could be positively related to success as the item is answered more carefully. However, the association may be negative if working faster indicates higher ability. The objective of this study was to clarify the validity of each assumption for reasoning items considering the mode of processing. A total of 230 persons completed a computerized version of Raven’s Advanced Progressive Matrices test. Results revealed that response time overall had a negative effect. However, this effect was moderated by items and persons. For easy items and able persons the effect was strongly negative, for difficult items and less able persons it was less negative or even positive. The number of rules involved in a matrix problem proved to explain item difficulty significantly. Most importantly, a positive interaction effect between the number of rules and item response time indicated that the response time effect became less negative with an increasing number of rules. Moreover, exploratory analyses suggested that the error type influenced the response time effect.

  17. Counting Frequencies from Zotero Items

    Directory of Open Access Journals (Sweden)

    Spencer Roberts

    2013-04-01

    Full Text Available In Counting Frequencies you learned how to count the frequency of specific words in a list using python. In this lesson, we will expand on that topic by showing you how to get information from Zotero HTML items, save the content from those items, and count the frequencies of words. It may be beneficial to look over the previous lesson before we begin.

  18. Direct binding of the Kex2p cytosolic tail to the VHS domain of yeast Gga2p facilitates TGN to prevacuolar compartment transport and is regulated by phosphorylation

    Science.gov (United States)

    De, Mithu; Abazeed, Mohamed E.; Fuller, Robert S.

    2013-01-01

    Human Golgi-localized, γ-ear–containing, ADP-ribosylation factor–binding proteins (Ggas) bind directly to acidic dileucine sorting motifs in the cytosolic tails (C-tails) of intracellular receptors. Despite evidence for a role in recruiting ubiquitinated cargo, it remains unclear whether yeast Ggas also function by binding peptide-sorting signals directly. Two-hybrid analysis shows that the Gga1p and Gga2p Vps27, Hrs, Stam (VHS) domains both bind a site in the Kex2p C-tail and that the Gga2p VHS domain binds a site in the Vps10p C-tail. Binding requires deletion of an apparently autoinhibitory sequence in the Gga2p hinge. Ser780 in the Kex2p C-tail is crucial for binding: an Ala substitution blocks but an Asp substitution permits binding. Biochemical assays using purified Gga2p VHS–GGA and TOM1 (GAT) and glutathione S-transferase–Kex2p C-tail fusions show that Gga2p binds directly to the Kex2p C-tail, with relative affinities Asp780 > Ser780 > Ala780. Affinity-purified antibody against a peptide containing phospho-Ser­780 recognizes wild-type Kex2p but not S780A Kex2p, showing that Ser780 is phosphorylated in vivo; phosphorylation of Ser780 is up-regulated by cell wall–damaging drugs. Finally, mutation of Ser780 alters trafficking of Kex2p both in vivo and in cell-free trans-Golgi network (TGN)–prevacuolar compartment (PVC) transport. Thus yeast Gga adaptors facilitate TGN–PVC transport by direct binding of noncanonical phosphoregulated Gga-binding sites in cargo molecules. PMID:23408788

  19. Numerosity estimates for attended and unattended items in visual search.

    Science.gov (United States)

    Kelley, Troy D; Cassenti, Daniel N; Marusich, Laura R; Ghirardelli, Thomas G

    2017-07-01

    The goal of this research was to examine memories created for the number of items during a visual search task. Participants performed a visual search task for a target defined by a single feature (Experiment 1A), by a conjunction of features (Experiment 1B), or by a specific spatial configuration of features (Experiment 1C). On some trials following the search task, subjects were asked to recall the total number of items in the previous display. In all search types, participants underestimated the total number of items, but the severity of the underestimation varied depending on the efficiency of the search. In three follow-up studies (Experiments 2A, 2B, and 2C) using the same visual stimuli, the participants' only task was to estimate the number of items on each screen. Participants still underestimated the numerosity of the items, although the degree of underestimation was smaller than in the search tasks and did not depend on the type of visual stimuli. In Experiment 3, participants were asked to recall the number of items in a display only once. Subjects still displayed a tendency to underestimate, indicating that the underestimation effects seen in Experiments 1A-1C were not attributable to knowledge of the estimation task. The degree of underestimation depends on the efficiency of the search task, with more severe underestimation in efficient search tasks. This suggests that the lower attentional demands of very efficient searches leads to less encoding of numerosity of the distractor set.

  20. An Item Gains and Losses Analysis of False Memories Suggests Critical Items Receive More Item-Specific Processing than List Items

    Science.gov (United States)

    Burns, Daniel J.; Martens, Nicholas J.; Bertoni, Alicia A.; Sweeney, Emily J.; Lividini, Michelle D.

    2006-01-01

    In a repeated testing paradigm, list items receiving item-specific processing are more likely to be recovered across successive tests (item gains), whereas items receiving relational processing are likely to be forgotten progressively less on successive tests. Moreover, analysis of cumulative-recall curves has shown that item-specific processing…

  1. The impact of item-writing flaws and item complexity on examination item difficulty and discrimination value

    National Research Council Canada - National Science Library

    Bonnie R Rush; David C Rankin; Brad J White

    2016-01-01

    .... This study evaluated faculty-authored examinations to determine the impact of item-writing flaws and item complexity on the difficulty and discrimination value of examination items used to assess...

  2. 9 CFR 93.912 - Import permits.

    Science.gov (United States)

    2010-01-01

    ... § 93.912 Import permits. (a) Live VHS-regulated fish imported from VHS-regulated regions through a... application for an import permit must be submitted for each shipment of live VHS-regulated fish to the Animal... intending to import live VHS-regulated fish into the United States; (4) The species and number of live VHS...

  3. Caries Risk Assessment Item Importance

    Science.gov (United States)

    Chaffee, B.W.; Featherstone, J.D.B.; Gansky, S.A.; Cheng, J.; Zhan, L.

    2016-01-01

    Caries risk assessment (CRA) is widely recommended for dental caries management. Little is known regarding how practitioners use individual CRA items to determine risk and which individual items independently predict clinical outcomes in children younger than 6 y. The objective of this study was to assess the relative importance of pediatric CRA items in dental providers’ decision making regarding patient risk and in association with clinically evident caries, cross-sectionally and longitudinally. CRA information was abstracted retrospectively from electronic patient records of children initially aged 6 to 72 mo at a university pediatric dentistry clinic (n = 3,810 baseline; n = 1,315 with follow-up). The 17-item CRA form included caries risk indicators, caries protective items, and clinical indicators. Conditional random forests classification trees were implemented to identify and assign variable importance to CRA items independently associated with baseline high-risk designation, baseline evident tooth decay, and follow-up evident decay. Thirteen individual CRA items, including all clinical indicators and all but 1 risk indicator, were independently and statistically significantly associated with student/resident providers’ caries risk designation. Provider-assigned baseline risk category was strongly associated with follow-up decay, which increased from low (20.4%) to moderate (30.6%) to high/extreme risk patients (68.7%). Of baseline CRA items, before adjustment, 12 were associated with baseline decay and 7 with decay at follow-up; however, in the conditional random forests models, only the clinical indicators (evident decay, dental plaque, and recent restoration placement) and 1 risk indicator (frequent snacking) were independently and statistically significantly associated with future disease, for which baseline evident decay was the strongest predictor. In this predominantly high-risk population under caries-preventive care, more individual CRA items

  4. Australian Item Bank Program: Social Science Item Bank.

    Science.gov (United States)

    Australian Council for Educational Research, Hawthorn.

    After vigorous review, editing, and trial testing, this item bank was compiled to help secondary school teachers construct objective tests in the social sciences. Anthropology, economics, ethnic and cultural studies, geography, history, legal studies, politics, and sociology are among the topics represented. The bank consists of multiple choice…

  5. Using a Model of Analysts' Judgments to Augment an Item Calibration Process

    Science.gov (United States)

    Hauser, Carl; Thum, Yeow Meng; He, Wei; Ma, Lingling

    2015-01-01

    When conducting item reviews, analysts evaluate an array of statistical and graphical information to assess the fit of a field test (FT) item to an item response theory model. The process can be tedious, particularly when the number of human reviews (HR) to be completed is large. Furthermore, such a process leads to decisions that are susceptible…

  6. What factors make science test items especially difficult for students from minority groups?

    Directory of Open Access Journals (Sweden)

    Are Turmo

    2012-06-01

    Full Text Available Substantial gaps in science performance between majority and minority students are often found instandardized tests used in primary school. But at the item level, the gaps may vary significantly. Theaims of this study are: (1 to identify features of the test items in science (grade 5 and grade 8 students that can potentially explain group differences; and (2 to analyze what factors make test itemsespecially difficult for minority students. Explanatory variables such as reading load, item difficulty,item writing load, and use of the multiple-choice format are found to be major factors. The analysis reveals no empirical relationships between performance gap and either item subject domain, item test location, or the number of illustrations used in the item. Subtle issues regarding the design ofitems may influence the size of the performance gap at item level over and above the main explanatory variables. The gap can be reduced significantly by choosing “minority friendly” items.

  7. Closed loop two-echelon repairable item systems

    NARCIS (Netherlands)

    Spanjers, L.; van Ommeren, Jan C.W.; Zijm, Willem H.M.

    In this paper we consider closed loop two-echelon repairable item systems with repair facilities both at a number of local service centers (called bases) and at a central location (the depot). The goal of the system is to maintain a number of production facilities (one at each base) in optimal

  8. Closed-loop two-echelon repairable item systems

    NARCIS (Netherlands)

    Spanjers, L.; Zijm, Willem H.M.; van Ommeren, Jan C.W.

    2003-01-01

    In this paper we consider closed loop two-echelon repairable item systems with repair facilities both at a number of local service centers (called bases) and at a central location (the depot). The goal of the system is to maintain a number of production facilities (one at each base) in optimal

  9. Closed loop two-echelon repairable item systems

    NARCIS (Netherlands)

    Spanjers, L.; van Ommeren, Jan C.W.; Zijm, Willem H.M.; Liberopoulos, G.; Papadopoulos, C.T.; Tan, B.; MacGregor Smith, J.; Gershwin, S.B.

    2006-01-01

    In this paper we consider closed loop two-echelon epairable item systems with repair facilities both at a number of local service centers (called bases) and at a central location (the depot). The goal of the system is to maintain a number of production facilities (one at each base) in optimal

  10. The variety, popularity and nutritional quality of tuck shop items ...

    African Journals Online (AJOL)

    Results: Savoury pies were the most popular lunch item for all learners for both breaks (n = 5, 45%, and n = 3, 27.3%), selling the most number of units (43) per day at eight schools (72.7%). Iced popsicles were sold at almost every school, ranked as the cheapest beverage, and also sold the most number of units (40.7).

  11. The variety, popularity and nutritional quality of tuck shop items ...

    African Journals Online (AJOL)

    2011-03-29

    Mar 29, 2011 ... Results: Savoury pies were the most popular lunch item for all learners for both breaks (n = 5, 45%, and n = 3, 27.3%), selling the most number of units (43) per day at eight schools (72.7%). Iced popsicles were sold at almost every school, ranked as the cheapest beverage, and also sold the most number of ...

  12. Differential Item Functioning (DIF): Current Problems and Future Directions

    Science.gov (United States)

    Karami, Hossein; Salmani Nodoushan, Mohammad Ali

    2011-01-01

    With the rising concerns over the fairness of language tests, Differential Item Functioning (DIF) has been increasingly applied in bias analysis. Despite its widespread use in psychometric circles, DIF is facing a number of serious problems. This paper is an attempt to shed light on a number of the issues involved in DIF analysis. Specifically,…

  13. Brief Sensation Seeking Scale: Latent structure of 8-item and 4-item versions in Peruvian adolescents.

    Science.gov (United States)

    Merino-Soto, Cesar; Salas Blas, Edwin

    2018-01-01

    This research intended to validate two brief scales of sensations seeking with Peruvian adolescents: the eight item scale (BSSS8; Hoyle, Stephenson, Palmgreen, Lorch, y Donohew, 2002) and the four item scale (BSSS4; Stephenson, Hoyle, Slater, y Palmgreen, 2003). Questionnaires were administered to 618 voluntary participants, with an average age of 13.6 years, from different levels of high school, state and private school in a district in the south of Lima. It analyzed the internal structure of both short versions using three models: a) unidimensional (M1), b) oblique or related dimensions (M2), and c) the bifactor model (M3). Results show that both instruments have a single dimension which best represents the variability of the items; a fact that can be explained both by the complexity of the concept and by the small number of items representing each factor, which is more noticeable in the BSSS4. Reliability is within levels found by previous studies: alpha: .745 = BSSS8 and BSSS4 =. 643; omega coefficient: .747 in BSSS8 and .651 in BSSS4. These are considered suitable for the type of instruments studied. Based on the correlation between the two instruments, it was found that there are satisfactory levels of equivalence between the BSSS8 and BSSS4. However, it is recommended that the BSSS4 is mainly used for research and for the purpose of describing populations.

  14. Generalizability theory and item response theory

    NARCIS (Netherlands)

    Glas, Cornelis A.W.; Eggen, T.J.H.M.; Veldkamp, B.P.

    2012-01-01

    Item response theory is usually applied to items with a selected-response format, such as multiple choice items, whereas generalizability theory is usually applied to constructed-response tasks assessed by raters. However, in many situations, raters may use rating scales consisting of items with a

  15. Unidimensional Interpretations for Multidimensional Test Items

    Science.gov (United States)

    Kahraman, Nilufer

    2013-01-01

    This article considers potential problems that can arise in estimating a unidimensional item response theory (IRT) model when some test items are multidimensional (i.e., show a complex factorial structure). More specifically, this study examines (1) the consequences of model misfit on IRT item parameter estimates due to unintended minor item-level…

  16. The impact of item-writing flaws and item complexity on examination item difficulty and discrimination value.

    Science.gov (United States)

    Rush, Bonnie R; Rankin, David C; White, Brad J

    2016-09-29

    Failure to adhere to standard item-writing guidelines may render examination questions easier or more difficult than intended. Item complexity describes the cognitive skill level required to obtain a correct answer. Higher cognitive examination items promote critical thinking and are recommended to prepare students for clinical training. This study evaluated faculty-authored examinations to determine the impact of item-writing flaws and item complexity on the difficulty and discrimination value of examination items used to assess third year veterinary students. The impact of item-writing flaws and item complexity (cognitive level I-V) on examination item difficulty and discrimination value was evaluated on 1925 examination items prepared by clinical faculty for third year veterinary students. The mean (± SE) percent correct (83.3 % ± 17.5) was consistent with target values in professional education, and the mean discrimination index (0.18 ± 0.17) was slightly lower than recommended (0.20). More than one item-writing flaw was identified in 37.3 % of questions. The most common item-writing flaws were awkward stem structure, implausible distractors, longest response is correct, and responses are series of true-false statements. Higher cognitive skills (complexity level III-IV) were required to correctly answer 38.4 % of examination items. As item complexity increased, item difficulty and discrimination values increased. The probability of writing discriminating, difficult examination items decreased when implausible distractors and all of the above were used, and increased if the distractors were comprised of a series of true/false statements. Items with four distractors were not more difficult or discriminating than items with three distractors. Preparation of examination questions targeting higher cognitive levels will increase the likelihood of constructing discriminating items. Use of implausible distractors to complete a five-option multiple choice

  17. The Psychological Effect of Errors in Standardized Language Test Items on EFL Students' Responses to the Following Item

    Science.gov (United States)

    Khaksefidi, Saman

    2017-01-01

    This study investigates the psychological effect of a wrong question with wrong items on answering to the next question in a test of structure. Forty students selected through stratified random sampling are given 15 questions of a standardized test namely a TOEFL structure test in which questions number 7 and number 11 are wrong and their answers…

  18. Teoria da Resposta ao Item Teoria de la respuesta al item Item response theory

    Directory of Open Access Journals (Sweden)

    Eutalia Aparecida Candido de Araujo

    2009-12-01

    Full Text Available A preocupação com medidas de traços psicológicos é antiga, sendo que muitos estudos e propostas de métodos foram desenvolvidos no sentido de alcançar este objetivo. Entre os trabalhos propostos, destaca-se a Teoria da Resposta ao Item (TRI que, a princípio, veio completar limitações da Teoria Clássica de Medidas, empregada em larga escala até hoje na medida de traços psicológicos. O ponto principal da TRI é que ela leva em consideração o item particularmente, sem relevar os escores totais; portanto, as conclusões não dependem apenas do teste ou questionário, mas de cada item que o compõe. Este artigo propõe-se a apresentar esta Teoria que revolucionou a teoria de medidas.La preocupación con las medidas de los rasgos psicológicos es antigua y muchos estudios y propuestas de métodos fueron desarrollados para lograr este objetivo. Entre estas propuestas de trabajo se incluye la Teoría de la Respuesta al Ítem (TRI que, en principio, vino a completar las limitaciones de la Teoría Clásica de los Tests, ampliamente utilizada hasta hoy en la medida de los rasgos psicológicos. El punto principal de la TRI es que se tiene en cuenta el punto concreto, sin relevar las puntuaciones totales; por lo tanto, los resultados no sólo dependen de la prueba o cuestionario, sino que de cada ítem que lo compone. En este artículo se propone presentar la Teoría que revolucionó la teoría de medidas.The concern with measures of psychological traits is old and many studies and proposals of methods were developed to achieve this goal. Among these proposed methods highlights the Item Response Theory (IRT that, in principle, came to complete limitations of the Classical Test Theory, which is widely used until nowadays in the measurement of psychological traits. The main point of IRT is that it takes into account the item in particular, not relieving the total scores; therefore, the findings do not only depend on the test or questionnaire

  19. Sharing the cost of redundant items

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Moulin, Hervé

    2014-01-01

    are network connectivity problems when an existing (possibly inefficient) network must be maintained. We axiomatize a family cost ratios based on simple liability indices, one for each agent and for each item, measuring the relative worth of this item across agents, and generating cost allocation rules......We ask how to share the cost of finitely many public goods (items) among users with different needs: some smaller subsets of items are enough to serve the needs of each user, yet the cost of all items must be covered, even if this entails inefficiently paying for redundant items. Typical examples...... additive in costs....

  20. Verbal fluency: Effect of time on item generation

    Directory of Open Access Journals (Sweden)

    Mayra Jacuviske Venegas

    Full Text Available Abstract The distribution of item generation/time in the performance of elderly on verbal fluency (VF remains unknown. Objective: To analyze the number of items, their distribution and impact of the first quartile on the final test result. Methods: 31 individuals performed the tests (average age=74 years; schooling=8.16 years. Results: The number of items produced in the first quartile differed from the other quartiles for both semantic and phonologic VF where 40% of items were produced in the first quartile. No effect of age was found and schooling influenced performance on the first and second quartiles of semantic VF and on the 1st, 2nd and 3rd quartiles of phonemic VF. Discussion: This study contributes with the finding that asymptotic levels are attained prior to the 30 seconds observed in other studies, being reached at the 15-second mark. Furthermore, schooling was found to be associated to the number of items produced in both the first and 2nd quartiles for semantic VF, and in 1st, 2nd and 3rd quartiles for phonemic fluency. Conclusion: The schooling effect was noted both in semantic and executive aspects of VF. The brief form of the VF test may represent a promising tool for clinical evaluation.

  1. Emergency Power For Critical Items

    Science.gov (United States)

    Young, William R.

    2009-07-01

    Natural disasters, such as hurricanes, floods, tornados, and tsunami, are becoming a greater problem as climate change impacts our environment. Disasters, whether natural or man made, destroy lives, homes, businesses and the natural environment. Such disasters can happen with little or no warning, leaving hundreds or even thousands of people without medical services, potable water, sanitation, communications and electrical services for up to several weeks. In our modern world, the need for electricity has become a necessity. Modern building codes and new disaster resistant building practices are reducing the damage to homes and businesses. Emergency gasoline and diesel generators are becoming common place for power outages. Generators need fuel, which may not be available after a disaster, but Photovoltaic (solar-electric) systems supply electricity without petroleum fuel as they are powered by the sun. Photovoltaic (PV) systems can provide electrical power for a home or business. PV systems can operate as utility interactive or stand-alone with battery backup. Determining your critical load items and sizing the photovoltaic system for those critical items, guarantees their operation in a disaster.

  2. Intact Transition Epitope Mapping (ITEM)

    Science.gov (United States)

    Yefremova, Yelena; Opuni, Kwabena F. M.; Danquah, Bright D.; Thiesen, Hans-Juergen; Glocker, Michael O.

    2017-08-01

    Intact transition epitope mapping (ITEM) enables rapid and accurate determination of protein antigen-derived epitopes by either epitope extraction or epitope excision. Upon formation of the antigen peptide-containing immune complex in solution, the entire mixture is electrosprayed to translate all constituents as protonated ions into the gas phase. There, ions from antibody-peptide complexes are separated from unbound peptide ions according to their masses, charges, and shapes either by ion mobility drift or by quadrupole ion filtering. Subsequently, immune complexes are dissociated by collision induced fragmentation and the ion signals of the "complex-released peptides," which in effect are the epitope peptides, are recorded in the time-of-flight analyzer of the mass spectrometer. Mixing of an antibody solution with a solution in which antigens or antigen-derived peptides are dissolved is, together with antigen proteolysis, the only required in-solution handling step. Simplicity of sample handling and speed of analysis together with very low sample consumption makes ITEM faster and easier to perform than other experimental epitope mapping methods.

  3. From distributed resources to limited slots in multiple-item working memory: a spiking network model with normalization

    National Research Council Canada - National Science Library

    Wei, Ziqiang; Wang, Xiao-Jing; Wang, Da-Hui

    2012-01-01

    ...: a "discrete-slot" model in which memory items are stored in a limited number of slots, and a "shared-resource" model in which the neural representation of items is distributed across a limited pool of resources...

  4. Item Analysis in Introductory Economics Testing.

    Science.gov (United States)

    Tinari, Frank D.

    1979-01-01

    Computerized analysis of multiple choice test items is explained. Examples of item analysis applications in the introductory economics course are discussed with respect to three objectives: to evaluate learning; to improve test items; and to help improve classroom instruction. Problems, costs and benefits of the procedures are identified. (JMD)

  5. Towards an authoring system for item construction

    NARCIS (Netherlands)

    Rikers, Jos H.A.N.

    1988-01-01

    The process of writing test items is analyzed, and a blueprint is presented for an authoring system for test item writing to reduce invalidity and to structure the process of item writing. The developmental methodology is introduced, and the first steps in the process are reported. A historical

  6. Real and Artificial Differential Item Functioning

    Science.gov (United States)

    Andrich, David; Hagquist, Curt

    2012-01-01

    The literature in modern test theory on procedures for identifying items with differential item functioning (DIF) among two groups of persons includes the Mantel-Haenszel (MH) procedure. Generally, it is not recognized explicitly that if there is real DIF in some items which favor one group, then as an artifact of this procedure, artificial DIF…

  7. FACTOR STRUCTURE OF MF SCALES AND ITEMS.

    Science.gov (United States)

    LUNNEBORG, CLIFFORD E.; LUNNEBORG, PATRICIA W.

    FACTOR ANALYSES WERE PERFORMED UPON FOUR MASCULINITY-FEMINITY (MF) SCALES AND UPON THE 136-ITEMS COMPRISING THESE SCALES. RESULTS OF THE FIRST ANALYSIS ILLUSTRATED THE DIFFICULTY OF INTERPRETING FACTORS BASED ON HETEROGENEOUS SCALES. THE ITEM FACTORING REVEALED THE MULTIDIMENSIONALITY OF MF. CERTAIN ITEM FACTORS WERE UNCORRELATED WITH SEX STATUS…

  8. Detection of differential item functioning using Lagrange multiplier tests

    NARCIS (Netherlands)

    Glas, Cornelis A.W.

    1998-01-01

    Abstract: In the present paper it is shown that differential item functioning can be evaluated using the Lagrange multiplier test or Rao’s efficient score test. The test is presented in the framework of a number of IRT models such as the Rasch model, the OPLM, the 2-parameter logistic model, the

  9. Sales Models For Many Items Using Attribute Data

    NARCIS (Netherlands)

    J.E.M. van Nierop; D. Fok (Dennis); Ph.H.B.F. Franses (Philip Hans)

    2002-01-01

    textabstractSales models are mainly used to analyze markets with a fairly small number of items, obtained after aggregating to the brand level. In practice one may require analyses at a more disaggregate level. For example, brand managers may be interested in a comparison across product attributes.

  10. Sales Models For Many Items Using Attribute Data

    NARCIS (Netherlands)

    J.E.M. van Nierop; D. Fok (Dennis); Ph.H.B.F. Franses (Philip Hans)

    2002-01-01

    textabstractSales models are mainly used to analyze markets with a fairly small number of items, obtained after aggregating to the brand level. In practice one may require analyses at a more disaggregate level. For example, brand managers may be interested in a comparison across product

  11. Number names and number understanding

    DEFF Research Database (Denmark)

    Ejersbo, Lisser Rye; Misfeldt, Morten

    2014-01-01

    through using mathematical names for the numbers such as one-ten-one for 11 and five-ten-six for 56. The project combines the renaming of numbers with supporting the teaching with the new number names. Our hypothesis is that Danish children have more difficulties learning and working with numbers, because...

  12. Losing Items in the Psychogeriatric Nursing Home

    Directory of Open Access Journals (Sweden)

    J. van Hoof PhD

    2016-09-01

    Full Text Available Introduction: Losing items is a time-consuming occurrence in nursing homes that is ill described. An explorative study was conducted to investigate which items got lost by nursing home residents, and how this affects the residents and family caregivers. Method: Semi-structured interviews and card sorting tasks were conducted with 12 residents with early-stage dementia and 12 family caregivers. Thematic analysis was applied to the outcomes of the sessions. Results: The participants stated that numerous personal items and assistive devices get lost in the nursing home environment, which had various emotional, practical, and financial implications. Significant amounts of time are spent on trying to find items, varying from 1 hr up to a couple of weeks. Numerous potential solutions were identified by the interviewees. Discussion: Losing items often goes together with limitations to the participation of residents. Many family caregivers are reluctant to replace lost items, as these items may get lost again.

  13. Proth Numbers

    Directory of Open Access Journals (Sweden)

    Schwarzweller Christoph

    2015-02-01

    Full Text Available In this article we introduce Proth numbers and prove two theorems on such numbers being prime [3]. We also give revised versions of Pocklington’s theorem and of the Legendre symbol. Finally, we prove Pepin’s theorem and that the fifth Fermat number is not prime.

  14. Assessing the item response theory with covariate (IRT-C) procedure for ascertaining differential item functioning

    NARCIS (Netherlands)

    Tay, L.; Vermunt, J.K.; Wang, C.

    2013-01-01

    We evaluate the item response theory with covariates (IRT-C) procedure for assessing differential item functioning (DIF) without preknowledge of anchor items (Tay, Newman, & Vermunt, 2011). This procedure begins with a fully constrained baseline model, and candidate items are tested for uniform

  15. RIM: A Random Item Mixture Model to Detect Differential Item Functioning

    Science.gov (United States)

    Frederickx, Sofie; Tuerlinckx, Francis; De Boeck, Paul; Magis, David

    2010-01-01

    In this paper we present a new methodology for detecting differential item functioning (DIF). We introduce a DIF model, called the random item mixture (RIM), that is based on a Rasch model with random item difficulties (besides the common random person abilities). In addition, a mixture model is assumed for the item difficulties such that the…

  16. One-dimensional Cutting Stock Problem with Divisible Items

    OpenAIRE

    Tanir, Deniz; Ugurlu, Onur; Guler, Asli; Nuriyev, Urfat

    2016-01-01

    This paper considers the one-dimensional cutting stock problem with divisible items, which is a new problem in the cutting stock literature. The problem exists in steel industries. In the new problem, each item can be divided into smaller pieces, then they can be recombined again by welding. The objective is to minimize both the trim loss and the number of the welds. We present a mathematical model and a dynamic programming based heuristic for the problem. Furthermore, a software, which is ba...

  17. Fibonacci numbers

    CERN Document Server

    Vorob'ev, Nikolai Nikolaevich

    2011-01-01

    Fibonacci numbers date back to an 800-year-old problem concerning the number of offspring born in a single year to a pair of rabbits. This book offers the solution and explores the occurrence of Fibonacci numbers in number theory, continued fractions, and geometry. A discussion of the ""golden section"" rectangle, in which the lengths of the sides can be expressed as a ration of two successive Fibonacci numbers, draws upon attempts by ancient and medieval thinkers to base aesthetic and philosophical principles on the beauty of these figures. Recreational readers as well as students and teacher

  18. Sagan numbers

    OpenAIRE

    Mendonça, J. Ricardo G.

    2012-01-01

    We define a new class of numbers based on the first occurrence of certain patterns of zeros and ones in the expansion of irracional numbers in a given basis and call them Sagan numbers, since they were first mentioned, in a special case, by the North-american astronomer Carl E. Sagan in his science-fiction novel "Contact." Sagan numbers hold connections with a wealth of mathematical ideas. We describe some properties of the newly defined numbers and indicate directions for further amusement.

  19. Algebraic Numbers

    Directory of Open Access Journals (Sweden)

    Watase Yasushige

    2016-12-01

    Full Text Available This article provides definitions and examples upon an integral element of unital commutative rings. An algebraic number is also treated as consequence of a concept of “integral”. Definitions for an integral closure, an algebraic integer and a transcendental numbers [14], [1], [10] and [7] are included as well. As an application of an algebraic number, this article includes a formal proof of a ring extension of rational number field ℚ induced by substitution of an algebraic number to the polynomial ring of ℚ[x] turns to be a field.

  20. From concepts to lexical items.

    Science.gov (United States)

    Bierwisch, M; Schreuder, R

    1992-03-01

    In this paper we address the question how in language production conceptual structures are mapped onto lexical items. First we describe the lexical system in a fairly abstract way. Such a system consists of, among other things, a fixed set of basic lexical entries characterized by four groups of information: phonetic form, grammatical features, argument structure, and semantic form. A crucial assumption of the paper is that the meaning in a lexical entry has a complex internal structure composed of more primitive elements (decomposition). Some aspects of argument structure and semantic form and their interaction are discussed with respect to the issue of synonymy. We propose two different mappings involved in lexical access. One maps conceptual structures to semantic forms, and the other maps semantic forms to conceptual structures. Both mappings are context dependent and are many-to-many mappings. We present an elaboration of Levelt's (1989) model in which these processes interact with the grammatical encoder and the mental lexicon. Then we address the consequences of decomposition for processing models, especially the nature of the input of lexical access and the time course. Processing models that use the activation metaphor may have difficulties accounting for certain phenomena where a certain lemma triggers not one, but two or more word forms that have to be produced with other word forms in between.

  1. Dependability of technical items: Problems of standardization

    Science.gov (United States)

    Fedotova, G. A.; Voropai, N. I.; Kovalev, G. F.

    2016-12-01

    This paper is concerned with problems blown up in the development of a new version of the Interstate Standard GOST 27.002 "Industrial product dependability. Terms and definitions". This Standard covers a wide range of technical items and is used in numerous regulations, specifications, standard and technical documentation. A currently available State Standard GOST 27.002-89 was introduced in 1990. Its development involved a participation of scientists and experts from different technical areas, its draft was debated in different audiences and constantly refined, so it was a high quality document. However, after 25 years of its application it's become necessary to develop a new version of the Standard that would reflect the current understanding of industrial dependability, accounting for the changes taking place in Russia in the production, management and development of various technical systems and facilities. The development of a new version of the Standard makes it possible to generalize on a terminological level the knowledge and experience in the area of reliability of technical items, accumulated over a quarter of the century in different industries and reliability research schools, to account for domestic and foreign experience of standardization. Working on the new version of the Standard, we have faced a number of issues and problems on harmonization with the International Standard IEC 60500-192, caused first of all by different approaches to the use of terms and differences in the mentalities of experts from different countries. The paper focuses on the problems related to the chapter "Maintenance, restoration and repair", which caused difficulties for the developers to harmonize term definitions both with experts and the International Standard, which is mainly related to differences between the Russian concept and practice of maintenance and repair and foreign ones.

  2. PENGEMBANGAN TES BERPIKIR KRITIS DENGAN PENDEKATAN ITEM RESPONSE THEORY

    Directory of Open Access Journals (Sweden)

    Fajrianthi Fajrianthi

    2016-06-01

    Assumption, Deduction, Interpretation dan Evaluation of arguments. 1453 respondents from Surabaya, Gresik, Tuban, Bojonegoro and Rembang were used for trailing the test. The dichotomous data were analized using the Item Response Theory with two parameter logistic model using statistical program Mplus ver. 6.11. Several assumptions were tested prior the IRT analysis; the test of unidimensionality, local independency and Item Characteristic Curve (ICC. Amongst 68 items only 15 items had good discrimination parameter. Difficulty item level ranged from – 4.95 to 2.448. The study was limited in producing high number of qualified items due to its failure in finding subject matter experts in critical thinking area and inadequate choice in scoring method. Keywords: test development, critical thinking, Item response theory

  3. Eulerian numbers

    CERN Document Server

    Petersen, T Kyle

    2015-01-01

    This text presents the Eulerian numbers in the context of modern enumerative, algebraic, and geometric combinatorics. The book first studies Eulerian numbers from a purely combinatorial point of view, then embarks on a tour of how these numbers arise in the study of hyperplane arrangements, polytopes, and simplicial complexes. Some topics include a thorough discussion of gamma-nonnegativity and real-rootedness for Eulerian polynomials, as well as the weak order and the shard intersection order of the symmetric group. The book also includes a parallel story of Catalan combinatorics, wherein the Eulerian numbers are replaced with Narayana numbers. Again there is a progression from combinatorics to geometry, including discussion of the associahedron and the lattice of noncrossing partitions. The final chapters discuss how both the Eulerian and Narayana numbers have analogues in any finite Coxeter group, with many of the same enumerative and geometric properties. There are four supplemental chapters throughout, ...

  4. Age, criterion flexibility, and item recognition.

    Science.gov (United States)

    North, Lione J; Olfman, Darlene; Caldera, Daniel R; Munoz, Emily; Light, Leah L

    2017-04-26

    We examined young and older adults' ability to flexibly adapt response criterion on a recognition test when the probability that a test item had been studied was cued by test color. One word color signaled that the probability of the test item being old was 70% and a second color signaled that the probability of the test item being new was 70%. Young and older adults demonstrated similar levels of criterion shifting in response to color cues. Moreover, although both young and older adults were slowed when test-item color incorrectly predicted test-item status, the extent of slowing did not differ across age group. Putative measures of cognitive control predicted recognition accuracy but not the degree to which criterion changed with test-item color. These results suggest that adaptive criterion shifting does not tax cognitive control or, if it does require effort, may be no more onerous for older than for young adults.

  5. [Instrument to measure adherence in hypertensive patients: contribution of Item Response Theory].

    Science.gov (United States)

    Rodrigues, Malvina Thaís Pacheco; Moreira, Thereza Maria Magalhaes; Vasconcelos, Alexandre Meira de; Andrade, Dalton Francisco de; Silva, Daniele Braz da; Barbetta, Pedro Alberto

    2013-06-01

    To analyze, by means of "Item Response Theory", an instrument to measure adherence to t treatment for hypertension. Analytical study with 406 hypertensive patients with associated complications seen in primary care in Fortaleza, CE, Northeastern Brazil, 2011 using "Item Response Theory". The stages were: dimensionality test, calibrating the items, processing data and creating a scale, analyzed using the gradual response model. A study of the dimensionality of the instrument was conducted by analyzing the polychoric correlation matrix and factor analysis of complete information. Multilog software was used to calibrate items and estimate the scores. Items relating to drug therapy are the most directly related to adherence while those relating to drug-free therapy need to be reworked because they have less psychometric information and low discrimination. The independence of items, the small number of levels in the scale and low explained variance in the adjustment of the models show the main weaknesses of the instrument analyzed. The "Item Response Theory" proved to be a relevant analysis technique because it evaluated respondents for adherence to treatment for hypertension, the level of difficulty of the items and their ability to discriminate between individuals with different levels of adherence, which generates a greater amount of information. The instrument analyzed is limited in measuring adherence to hypertension treatment, by analyzing the "Item Response Theory" of the item, and needs adjustment. The proper formulation of the items is important in order to accurately measure the desired latent trait.

  6. Time course study of in situ expression of antigens following DNA-vaccination against VHS in rainbow trout (Oncorhynchus mykiss Walbaum) fry

    DEFF Research Database (Denmark)

    Lorenzen, Ellen; Lorenzen, Niels; Einer-Jensen, Katja

    2005-01-01

    by immunohistochemistry for the viral G-protein mainly in the membrane of intact myocytes, most prominent by days 10-27, and with concomitant infiltration of inflammatory cells by days 13-38 that subsequently lead to a marked reduction in the number of myocytes expressing the G-protein. By immunofluorescence......, infiltrating cells positive for MHC II, IgM, and C3 were demonstrated. By contrast, in fish vaccinated with the VHSV-N construct, fewer, diffusely positive myocytes were found, most prominent by days 13-38, these having a positive reaction for the N-protein mainly in the cytoplasm and variably in the membrane....... N-protein positive myocytes did not attract infiltrating cells to the same degree. Positive reaction for the N-protein almost ceased by day 48 post-vaccination....

  7. Human resource management in the delivery of postal items

    Directory of Open Access Journals (Sweden)

    Kujačić Momčilo D.

    2015-01-01

    Full Text Available Delivery of postal items is the last phase in the postal conveyance process. This phase involved up to 57% in total costs of postal items conveyance. In order to reduce the costs of delivery phase, postal organizations apply different methods and techniques. Legal and technological regulations, various restrictions regarding the selection and deployment of employees influence the choice of appropriate methods. Also, the principle of availability of the universal postal service is an essential factor in defining the optimal model. In this paper, the model for assessing and planning of the number of employees in the delivery service observed postal operator has been proposed, with respect to the principles of productivity and accessibility constraints of the universal postal service. This paper will analyze the impact of daily fluctuations in the number of full-time employees and the possibility of hiring a part-time workers in the days with increased traffic volume in the delivery of items, when usually the items from large customers are delivered.

  8. Number theory

    CERN Document Server

    Andrews, George E

    1994-01-01

    Although mathematics majors are usually conversant with number theory by the time they have completed a course in abstract algebra, other undergraduates, especially those in education and the liberal arts, often need a more basic introduction to the topic.In this book the author solves the problem of maintaining the interest of students at both levels by offering a combinatorial approach to elementary number theory. In studying number theory from such a perspective, mathematics majors are spared repetition and provided with new insights, while other students benefit from the consequent simpl

  9. Exploring differential item functioning in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC

    Directory of Open Access Journals (Sweden)

    Pollard Beth

    2012-12-01

    Full Text Available Abstract Background The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC is a widely used patient reported outcome in osteoarthritis. An important, but frequently overlooked, aspect of validating health outcome measures is to establish if items exhibit differential item functioning (DIF. That is, if respondents have the same underlying level of an attribute, does the item give the same score in different subgroups or is it biased towards one subgroup or another. The aim of the study was to explore DIF in the Likert format WOMAC for the first time in a UK osteoarthritis population with respect to demographic, social, clinical and psychological factors. Methods The sample comprised a community sample of 763 people with osteoarthritis who participated in the Somerset and Avon Survey of Health. The WOMAC was explored for DIF by gender, age, social deprivation, social class, employment status, distress, body mass index and clinical factors. Ordinal regression models were used to identify DIF items. Results After adjusting for age, two items were identified for the physical functioning subscale as having DIF with age identified as the DIF factor for 2 items, gender for 1 item and body mass index for 1 item. For the WOMAC pain subscale, for people with hip osteoarthritis one item was identified with age-related DIF. The impact of the DIF items rarely had a significant effect on the conclusions of group comparisons. Conclusions Overall, the WOMAC performed well with only a small number of DIF items identified. However, as DIF items were identified in for the WOMAC physical functioning subscale it would be advisable to analyse data taking into account the possible impact of the DIF items when weight, gender or especially age effects, are the focus of interest in UK-based osteoarthritis studies. Similarly for the WOMAC pain subscale in people with hip osteoarthritis it would be worthwhile to analyse data taking into account the

  10. 75 FR 14459 - Notice of Intent to Repatriate Cultural Items: Western Reserve Historical Society, Cleveland, OH

    Science.gov (United States)

    2010-03-25

    ... National Park Service Notice of Intent to Repatriate Cultural Items: Western Reserve Historical Society... to repatriate cultural items in the possession of the Western Reserve Historical Society, Cleveland... 1867, the Western Reserve Historical Society was founded. Starting in 1894, book numbers were assigned...

  11. 48 CFR 52.232-30 - Installment Payments for Commercial Items.

    Science.gov (United States)

    2010-10-01

    ... contract award to the date one month before the first delivery of the first separately priced unit of the contract line item. For example, if the first scheduled delivery of any separately priced unit of a... contract line item begin the number of months prior to the delivery of that unit that are equal to the...

  12. Nice numbers

    CERN Document Server

    Barnes, John

    2016-01-01

    In this intriguing book, John Barnes takes us on a journey through aspects of numbers much as he took us on a geometrical journey in Gems of Geometry. Similarly originating from a series of lectures for adult students at Reading and Oxford University, this book touches a variety of amusing and fascinating topics regarding numbers and their uses both ancient and modern. The author intrigues and challenges his audience with both fundamental number topics such as prime numbers and cryptography, and themes of daily needs and pleasures such as counting one's assets, keeping track of time, and enjoying music. Puzzles and exercises at the end of each lecture offer additional inspiration, and numerous illustrations accompany the reader. Furthermore, a number of appendices provides in-depth insights into diverse topics such as Pascal’s triangle, the Rubik cube, Mersenne’s curious keyboards, and many others. A theme running through is the thought of what is our favourite number. Written in an engaging and witty sty...

  13. Evaluation of psychometric properties and differential item functioning of 8-item Child Perceptions Questionnaires using item response theory.

    Science.gov (United States)

    Yau, David T W; Wong, May C M; Lam, K F; McGrath, Colman

    2015-08-19

    Four-factor structure of the two 8-item short forms of Child Perceptions Questionnaire CPQ11-14 (RSF:8 and ISF:8) has been confirmed. However, the sum scores are typically reported in practice as a proxy of Oral health-related Quality of Life (OHRQoL), which implied a unidimensional structure. This study first assessed the unidimensionality of 8-item short forms of CPQ11-14. Item response theory (IRT) was employed to offer an alternative and complementary approach of validation and to overcome the limitations of classical test theory assumptions. A random sample of 649 12-year-old school children in Hong Kong was analyzed. Unidimensionality of the scale was tested by confirmatory factor analysis (CFA), principle component analysis (PCA) and local dependency (LD) statistic. Graded response model was fitted to the data. Contribution of each item to the scale was assessed by item information function (IIF). Reliability of the scale was assessed by test information function (TIF). Differential item functioning (DIF) across gender was identified by Wald test and expected score functions. Both CPQ11-14 RSF:8 and ISF:8 did not deviate much from the unidimensionality assumption. Results from CFA indicated acceptable fit of the one-factor model. PCA indicated that the first principle component explained >30 % of the total variation with high factor loadings for both RSF:8 and ISF:8. Almost all LD statistic dependency. Flat and low IIFs were observed in the oral symptoms items suggesting little contribution of information to the scale and item removal caused little practical impact. Comparing the TIFs, RSF:8 showed slightly better information than ISF:8. In addition to oral symptoms items, the item "Concerned with what other people think" demonstrated a uniform DIF (p < 0.001). The expected score functions were not much different between boys and girls. Items related to oral symptoms were not informative to OHRQoL and deletion of these items is suggested. The impact of

  14. Determinants of Difficulty and Discriminating Power of Image-based Test Items in Postgraduate Radiological Examinations.

    Science.gov (United States)

    Rutgers, Dirk R; van Raamt, Fleur; van der Gijp, Anouk; Mol, Christian; Ten Cate, Olle

    2017-11-29

    The psychometric characteristics of image-based test items in radiological written examinations are not well known. In this study, we explored difficulty and discriminating power of these test items in postgraduate radiological digital examinations. We reviewed test items of seven Dutch Radiology Progress Tests (DRPTs) that were taken from October 2013 to April 2017. The DRPT is a semiannual formative examination, required for all Dutch radiology residents. We assessed several stimulus and response characteristics of test items. The response format of test items included true or false, single right multiple choice with 2, 3, 4, or ≥5 answer options, pick-N multiple-choice, drag-and-drop, and long-list-menu formats. We calculated item P values and item-rest-correlation (Rir) values to assess difficulty and discriminating power. We performed linear regression analysis in image-based test items to investigate whether P and Rir values were significantly related to stimulus and response characteristics. Also, we compared psychometric indices between image-based test items and text-alone items. P and Rir values of image-based items (n = 369) were significantly related to the type of response format (P < .001), and not to which of the seven DRPTs the item was obtained from, radiological subspecialty domain, nonvolumetric or volumetric character of images, or context-rich or context-free character of the stimulus. When accounted for type of response format, difficulty and discriminating power of image-based items did not differ significantly from text-alone items (n = 881). Test items with a relatively large number of answer options were generally more difficult, and discriminated better among high- and low-performing candidates. In postgraduate radiological written examinations, difficulty and discriminating power of image-based test items are related to the type of response format and are comparable to those of text-alone items. We recommend a response

  15. Reliability estimation for single dichotomous items

    NARCIS (Netherlands)

    Meijer, R.R.; Sijtsma, Klaas; Molenaar, Ivo W.

    1994-01-01

    Three methods for the estimation of the reliability of single dichotomous items are discussed. All methods are based on the assumptions of nondecreasing and nonintersecting item response functions and the Mokken model of double monotonicity. Based on analytical and Monte Carlo studies, it is

  16. Restricted Interests and Teacher Presentation of Items

    Science.gov (United States)

    Stocco, Corey S.; Thompson, Rachel H.; Rodriguez, Nicole M.

    2011-01-01

    Restricted and repetitive behavior (RRB) is more pervasive, prevalent, frequent, and severe in individuals with autism spectrum disorders (ASDs) than in their typical peers. One subtype of RRB is restricted interests in items or activities, which is evident in the manner in which individuals engage with items (e.g., repetitious wheel spinning),…

  17. 38 CFR 3.1606 - Transportation items.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Transportation items. 3... Burial Benefits § 3.1606 Transportation items. The transportation costs of those persons who come within... shipment. (6) Cost of transportation by common carrier including amounts paid as Federal taxes. (7) Cost of...

  18. Accuracy in Rating and Recommending Item Features

    NARCIS (Netherlands)

    L. Rutledge (Lloyd); N. Stash; Y. Wang (Yanjing); L. Aroyo

    2008-01-01

    textabstractThis paper discusses accuracy in processing ratings of and recommendations for item features. Such processing facilitates featurebased user navigation in recommender system interfaces. Item features, often in the form of tags, categories or meta-data, are becoming important hypertext

  19. Evaluating model assumptions in item response theory

    NARCIS (Netherlands)

    Tijmstra, J.

    2013-01-01

    This dissertation deals with the evaluation of model assumptions in the context of item response theory. Item response theory, also known as modern test theory, provides a statistical framework for the measurement of psychological constructs that cannot by observed directly, such as intelligence or

  20. The 24-item Brief HEXACO Inventory (BHI)

    NARCIS (Netherlands)

    de Vries, R.E.

    2013-01-01

    Up until now, no really short instrument that measures the six personality dimensions of the HEXACO model has been available. In two studies, I report the construction of the Brief HEXACO Inventory (BHI), which represents the 24 HEXACO facets with 1 item per facet (i.e., 4 items per domain) and

  1. Invariant Ordering of Item-Total Regressions

    Science.gov (United States)

    Tijmstra, Jesper; Hessen, David J.; van der Heijden, Peter G. M.; Sijtsma, Klaas

    2011-01-01

    A new observable consequence of the property of invariant item ordering is presented, which holds under Mokken's double monotonicity model for dichotomous data. The observable consequence is an invariant ordering of the item-total regressions. Kendall's measure of concordance "W" and a weighted version of this measure are proposed as measures for…

  2. Double Modals as Single Lexical Items.

    Science.gov (United States)

    Di Paolo, Marianna

    1989-01-01

    Study of East and West Texans' (N=62) use of double modals as single lexical items and their syntactic and semantic characteristics found that neither Aux nor subcategorization analysis could account for both single-modal and double-modal dialects. Double modals, however, could conceivably be analyzed as two-word lexical items such as idioms or…

  3. Recovery of unrehearsed items in connectionist models.

    NARCIS (Netherlands)

    Murre, J.M.J.; Atkins, P.W.B.

    1998-01-01

    When gradient-descent models with hidden units are retrained on a portion of a previously learned set of items, performance on both the relearned and unrelearned items improves. Previous explanations of this phenomenon have not adequately distinguished recovery, which is dependent on original

  4. Recovery of unrehearsed items in connectionist models

    NARCIS (Netherlands)

    Murre, J.M.J.; Atkins, P.W.B.

    1998-01-01

    When gradient-descent models with hidden units are retrained on a portion of a previously learned set of items, performance on both the relearned and unrelearned items improves. Previous explanations of this phenomenon have not adequately distinguished recovery, which is dependent on original

  5. Factoring handedness data: I. Item analysis.

    Science.gov (United States)

    Messinger, H B; Messinger, M I

    1995-12-01

    Recently in this journal Peters and Murphy challenged the validity of factor analyses done on bimodal handedness data, suggesting instead that right- and left-handers be studied separately. But bimodality may be avoidable if attention is paid to Oldfield's questionnaire format and instructions for the subjects. Two characteristics appear crucial: a two-column LEFT-RIGHT format for the body of the instrument and what we call Oldfield's Admonition: not to indicate strong preference for handedness item, such as write, unless "... the preference is so strong that you would never try to use the other hand unless absolutely forced to...". Attaining unimodality of an item distribution would seem to overcome the objections of Peters and Murphy. In a 1984 survey in Boston we used Oldfield's ten-item questionnaire exactly as published. This produced unimodal item distributions. With reflection of the five-point item scale and a logarithmic transformation, we achieved a degree of normalization for the items. Two surveys elsewhere based on Oldfield's 20-item list but with changes in the questionnaire format and the instructions, yielded markedly different item distributions with peaks at each extreme and sometimes in the middle as well.

  6. Comparison on Computed Tomography using industrial items

    DEFF Research Database (Denmark)

    Angel, Jais Andreas Breusch; De Chiffre, Leonardo

    2014-01-01

    In a comparison involving 27 laboratories from 8 countries, measurements on two common industrial items, a polymer part and a metal part, were carried out using X-ray Computed Tomography. All items were measured using coordinate measuring machines before and after circulation, with reference...

  7. Exploratory Item Classification Via Spectral Graph Clustering.

    Science.gov (United States)

    Chen, Yunxiao; Li, Xiaoou; Liu, Jingchen; Xu, Gongjun; Ying, Zhiliang

    2017-01-01

    Large-scale assessments are supported by a large item pool. An important task in test development is to assign items into scales that measure different characteristics of individuals, and a popular approach is cluster analysis of items. Classical methods in cluster analysis, such as the hierarchical clustering, K-means method, and latent-class analysis, often induce a high computational overhead and have difficulty handling missing data, especially in the presence of high-dimensional responses. In this article, the authors propose a spectral clustering algorithm for exploratory item cluster analysis. The method is computationally efficient, effective for data with missing or incomplete responses, easy to implement, and often outperforms traditional clustering algorithms in the context of high dimensionality. The spectral clustering algorithm is based on graph theory, a branch of mathematics that studies the properties of graphs. The algorithm first constructs a graph of items, characterizing the similarity structure among items. It then extracts item clusters based on the graphical structure, grouping similar items together. The proposed method is evaluated through simulations and an application to the revised Eysenck Personality Questionnaire.

  8. Examining the Effect of Reverse Worded Items on the Factor Structure of the Need for Cognition Scale.

    Directory of Open Access Journals (Sweden)

    Xijuan Zhang

    Full Text Available Reverse worded (RW items are often used to reduce or eliminate acquiescence bias, but there is a rising concern about their harmful effects on the covariance structure of the scale. Therefore, results obtained via traditional covariance analyses may be distorted. This study examined the effect of the RW items on the factor structure of the abbreviated 18-item Need for Cognition (NFC scale using confirmatory factor analysis. We modified the scale to create three revised versions, varying from no RW items to all RW items. We also manipulated the type of the RW items (polar opposite vs. negated. To each of the four scales, we fit four previously developed models. The four models included a 1-factor model, a 2-factor model distinguishing between positively worded (PW items and RW items, and two 2-factor models, each with one substantive factor and one method factor. Results showed that the number and type of the RW items affected the factor structure of the NFC scale. Consistent with previous research findings, for the original NFC scale, which contains both PW and RW items, the 1-factor model did not have good fit. In contrast, for the revised scales that had no RW items or all RW items, the 1-factor model had reasonably good fit. In addition, for the scale with polar opposite and negated RW items, the factor model with a method factor among the polar opposite items had considerably better fit than the 1-factor model.

  9. Elaborate Item Count Questioning: Why Do People Underreport in Item Count Responses?

    National Research Council Canada - National Science Library

    Takahiro Tsuchiya; Yoko Hirai

    2010-01-01

    ... `applies/does not apply' responses to each item. Because this inconsistency, which we refer to as the underreporting effect, often disturbs proper item count estimates, the causes of this effect are explored in this paper...

  10. The use of an item response theory-based disability item bank across diseases: accounting for differential item functioning.

    Science.gov (United States)

    Weisscher, Nadine; Glas, Cees A; Vermeulen, Marinus; De Haan, Rob J

    2010-05-01

    There is not a single universally accepted activity of daily living (ADL) instrument available to compare disability assessments across different patient groups. We developed a generic item bank of ADL items using item response theory, the Academic Medical Center Linear Disability Scale (ALDS). When comparing outcomes of the ALDS between patients groups, item characteristics of the ALDS should be comparable across groups. The aim of the study was to assess the differential item functioning (DIF) in a group of patients with various disorders to investigate the comparability across these groups. Cross-sectional, multicenter study including 1,283 in- and outpatients with a variety of disorders and disability levels. The sample was divided in two groups: (1) mainly neurological patients (n=497; vascular medicine, Parkinson's disease and neuromuscular disorders) and (2) patients from internal medicine (n=786; pulmonary diseases, chronic pain, rheumatoid arthritis, and geriatric patients). Eighteen of 72 ALDS items showed statistically significant DIF (P<0.01). However, the DIF could effectively be modeled by the introduction of disease-specific parameters. In the subgroups studied, DIF could be modeled in such a way that the ensemble of the items comprised a scale applicable in both groups.

  11. Binary classification of items of interest in a repeatable process

    Science.gov (United States)

    Abell, Jeffrey A; Spicer, John Patrick; Wincek, Michael Anthony; Wang, Hui; Chakraborty, Debejyo

    2015-01-06

    A system includes host and learning machines. Each machine has a processor in electrical communication with at least one sensor. Instructions for predicting a binary quality status of an item of interest during a repeatable process are recorded in memory. The binary quality status includes passing and failing binary classes. The learning machine receives signals from the at least one sensor and identifies candidate features. Features are extracted from the candidate features, each more predictive of the binary quality status. The extracted features are mapped to a dimensional space having a number of dimensions proportional to the number of extracted features. The dimensional space includes most of the passing class and excludes at least 90 percent of the failing class. Received signals are compared to the boundaries of the recorded dimensional space to predict, in real time, the binary quality status of a subsequent item of interest.

  12. Representation of item position in immediate serial recall: Evidence from intrusion errors.

    Science.gov (United States)

    Fischer-Baum, Simon; McCloskey, Michael

    2015-09-01

    In immediate serial recall, participants are asked to recall novel sequences of items in the correct order. Theories of the representations and processes required for this task differ in how order information is maintained; some have argued that order is represented through item-to-item associations, while others have argued that each item is coded for its position in a sequence, with position being defined either by distance from the start of the sequence, or by distance from both the start and the end of the sequence. Previous researchers have used error analyses to adjudicate between these different proposals. However, these previous attempts have not allowed researchers to examine the full set of alternative proposals. In the current study, we analyzed errors produced in 2 immediate serial recall experiments that differ in the modality of input (visual vs. aural presentation of words) and the modality of output (typed vs. spoken responses), using new analysis methods that allow for a greater number of alternative hypotheses to be considered. We find evidence that sequence positions are represented relative to both the start and the end of the sequence, and show a contribution of the end-based representation beyond the final item in the sequence. We also find limited evidence for item-to-item associations, suggesting that both a start-end positional scheme and item-to-item associations play a role in representing item order in immediate serial recall. (c) 2015 APA, all rights reserved).

  13. Funny Numbers

    Directory of Open Access Journals (Sweden)

    Theodore M. Porter

    2012-12-01

    Full Text Available The struggle over cure rate measures in nineteenth-century asylums provides an exemplary instance of how, when used for official assessments of institutions, these numbers become sites of contestation. The evasion of goals and corruption of measures tends to make these numbers “funny” in the sense of becoming dis-honest, while the mismatch between boring, technical appearances and cunning backstage manipulations supplies dark humor. The dangers are evident in recent efforts to decentralize the functions of governments and corporations using incen-tives based on quantified targets.

  14. Software Note: Using BILOG for Fixed-Anchor Item Calibration

    Science.gov (United States)

    DeMars, Christine E.; Jurich, Daniel P.

    2012-01-01

    The nonequivalent groups anchor test (NEAT) design is often used to scale item parameters from two different test forms. A subset of items, called the anchor items or common items, are administered as part of both test forms. These items are used to adjust the item calibrations for any differences in the ability distributions of the groups taking…

  15. Designing P-Optimal Item Pools in Computerized Adaptive Tests with Polytomous Items

    Science.gov (United States)

    Zhou, Xuechun

    2012-01-01

    Current CAT applications consist of predominantly dichotomous items, and CATs with polytomously scored items are limited. To ascertain the best approach to polytomous CAT, a significant amount of research has been conducted on item selection, ability estimation, and impact of termination rules based on polytomous IRT models. Few studies…

  16. Computerized Adaptive Test (CAT) Applications and Item Response Theory Models for Polytomous Items

    Science.gov (United States)

    Aybek, Eren Can; Demirtasli, R. Nukhet

    2017-01-01

    This article aims to provide a theoretical framework for computerized adaptive tests (CAT) and item response theory models for polytomous items. Besides that, it aims to introduce the simulation and live CAT software to the related researchers. Computerized adaptive test algorithm, assumptions of item response theory models, nominal response…

  17. AN ITEM RESPONSE MODEL WITH SINGLE PEAKED ITEM CHARACTERISTIC CURVES - THE PARELLA MODEL

    NARCIS (Netherlands)

    HOIJTINK, H; MOLENAAR, [No Value

    In this paper an item response model (the PARELLA model) designed specifically for the measurement of attitudes and preferences will be introduced. In contrast with the item response models currently used (e.g. the Rasch model and, the two and three parameter logistic model) the item characteristic

  18. The Generalized Logit-Linear Item Response Model for Binary-Designed Items

    Science.gov (United States)

    Revuelta, Javier

    2008-01-01

    This paper introduces the generalized logit-linear item response model (GLLIRM), which represents the item-solving process as a series of dichotomous operations or steps. The GLLIRM assumes that the probability function of the item response is a logistic function of a linear composite of basic parameters which describe the operations, and the…

  19. A Regional and Local Item Response Theory Based Test Item Bank System.

    Science.gov (United States)

    Hathaway, Walter; And Others

    This report describes the development, operation, maintenance, and future prospects of the item banks pioneered by the Portland (Oregon) School District. At the time of this report, there were 3,500 mathematics, 2,200 reading, and 2,300 language usage items calibrated under the fixed parameter model of item response theory (IRT) for Grades 3-8.…

  20. Item level diagnostics and model - data fit in item response theory ...

    African Journals Online (AJOL)

    ... when using BILOG-MG V3.0. Five items fitted 2-parameter models in IRTPRO. It was recommended that the use of more than one IRT software programme offers more useful information for the choice of model that fit the data. KEYWORDS: Item Level, Diagnostics, Statistics, Model - Data Fit, Item Response Theory (IRT).

  1. Interactions Between Item Content And Group Membership on Achievement Test Items.

    Science.gov (United States)

    Linn, Robert L.; Harnisch, Delwyn L.

    The purpose of this investigation was to examine the interaction of item content and group membership on achievement test items. Estimates of the parameters of the three parameter logistic model were obtained on the 46 item math test for the sample of eighth grade students (N = 2055) participating in the Illinois Inventory of Educational Progress,…

  2. RIM: A random item mixture model to detect Differential Item Functioning

    NARCIS (Netherlands)

    Frederickx, S.; Tuerlinckx, T.; de Boeck, P.; Magis, D.

    2010-01-01

    In this paper we present a new methodology for detecting differential item functioning (DIF). We introduce a DIF model, called the random item mixture (RIM), that is based on a Rasch model with random item difficulties (besides the common random person abilities). In addition, a mixture model is

  3. Transfinite Numbers

    Indian Academy of Sciences (India)

    How many points are there on a line? Which is more in number- points on a line or lines in a plane? These are some natural questions that have occurred to us sometime or the other. It is interesting to note the difference between the two questions. Do we have to know how many points and lines there are to answer.

  4. Triangular Numbers

    Indian Academy of Sciences (India)

    Admin

    Left: Anuradha S Garge completed her PhD from. Pune University in 2008 under the supervision of Prof. S A Katre. Her research interests include K-theory and number theory. Besides mathematics, she is interested in (singing) indian classical music and yoga. Right: Shailesh Shirali is. Director of Sahyadri School.

  5. Exploring differential item functioning in the SF-36 by demographic, clinical, psychological and social factors in an osteoarthritis population.

    Science.gov (United States)

    Pollard, Beth; Johnston, Marie; Dixon, Diane

    2013-12-11

    The SF-36 is a very commonly used generic measure of health outcome in osteoarthritis (OA). An important, but frequently overlooked, aspect of validating health outcome measures is to establish if items work in the same way across subgroup of a population. That is, if respondents have the same 'true' level of outcome, does the item give the same score in different subgroups or is it biased towards one subgroup or another. Differential item functioning (DIF) can identify items that may be biased for one group or another and has been applied to measuring patient reported outcomes. Items may show DIF for different conditions and between cultures, however the SF-36 has not been specifically examined in an osteoarthritis population nor in a UK population. Hence, the aim of the study was to apply the DIF method to the SF-36 for a UK OA population. The sample comprised a community sample of 763 people with OA who participated in the Somerset and Avon Survey of Health. The SF-36 was explored for DIF with respect to demographic, social, clinical and psychological factors. Well developed ordinal regression models were used to identify DIF items. DIF items were found by age (6 items), employment status (6 items), social class (2 items), mood (2 items), hip v knee (2 items), social deprivation (1 item) and body mass index (1 item). Although the impact of the DIF items rarely had a significant effect on the conclusions of group comparisons, in most cases there was a significant change in effect size. Overall, the SF-36 performed well with only a small number of DIF items identified, a reassuring finding in view of the frequent use of the SF-36 in OA. Nevertheless, where DIF items were identified it would be advisable to analyse data taking account of DIF items, especially when age effects are the focus of interest.

  6. Item response theory for measurement validity.

    Science.gov (United States)

    Yang, Frances M; Kao, Solon T

    2014-06-01

    Item response theory (IRT) is an important method of assessing the validity of measurement scales that is underutilized in the field of psychiatry. IRT describes the relationship between a latent trait (e.g., the construct that the scale proposes to assess), the properties of the items in the scale, and respondents' answers to the individual items. This paper introduces the basic premise, assumptions, and methods of IRT. To help explain these concepts we generate a hypothetical scale using three items from a modified, binary (yes/no) response version of the Center for Epidemiological Studies-Depression scale that was administered to 19,399 respondents. We first conducted a factor analysis to confirm the unidimensionality of the three items and then proceeded with Mplus software to construct the 2-Parameter Logic (2-PL) IRT model of the data, a method which allows for estimates of both item discrimination and item difficulty. The utility of this information both for clinical purposes and for scale construction purposes is discussed.

  7. Measuring student learning with item response theory

    Science.gov (United States)

    Lee, Young-Jin; Palazzo, David J.; Warnakulasooriya, Rasil; Pritchard, David E.

    2008-06-01

    We investigate short-term learning from hints and feedback in a Web-based physics tutoring system. Both the skill of students and the difficulty and discrimination of items were determined by applying item response theory (IRT) to the first answers of students who are working on for-credit homework items in an introductory Newtonian physics course. We show that after tutoring a shifted logistic item response function with lower discrimination fits the students’ second responses to an item previously answered incorrectly. Student skill decreased by 1.0 standard deviation when students used no tutoring between their (incorrect) first and second attempts, which we attribute to “item-wrong bias.” On average, using hints or feedback increased students’ skill by 0.8 standard deviation. A skill increase of 1.9 standard deviation was observed when hints were requested after viewing, but prior to attempting to answer, a particular item. The skill changes measured in this way will enable the use of IRT to assess students based on their second attempt in a tutoring environment.

  8. Calorie Changes in Large Chain Restaurants: Declines in New Menu Items but Room for Improvement.

    Science.gov (United States)

    Bleich, Sara N; Wolfson, Julia A; Jarlenski, Marian P

    2016-01-01

    Large chain restaurants reduced the number of calories in newly introduced menu items in 2013 by about 60 calories (or 12%) relative to 2012. This paper describes trends in calories available in large U.S. chain restaurants to understand whether previously documented patterns persist. Data (a census of items for included restaurants) were obtained from the MenuStat project. This analysis included 66 of the 100 largest U.S. restaurants that are available in all three of the data years (2012-2014; N=23,066 items). Generalized linear models were used to examine: (1) per-item calorie changes from 2012 to 2014 among items on the menu in all years; and (2) mean calories in new items in 2013 and 2014 compared with items on the menu in 2012 only. Data were analyzed in 2014. Overall, calories in newly introduced menu items declined by 71 (or 15%) from 2012 to 2013 (p=0.001) and by 69 (or 14%) from 2012 to 2014 (p=0.03). These declines were concentrated mainly in new main course items (85 fewer calories in 2013 and 55 fewer calories in 2014; p=0.01). Although average calories in newly introduced menu items are declining, they are higher than items common to the menu in all 3 years. No differences in mean calories among items on menus in 2012, 2013, or 2014 were found. The previously observed declines in newly introduced menu items among large restaurant chains have been maintained, which suggests the beginning of a trend toward reducing calories. Copyright © 2016 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  9. Number names and number understanding

    DEFF Research Database (Denmark)

    Ejersbo, Lisser Rye; Misfeldt, Morten

    2014-01-01

    This paper concerns the results from the first year of a three-year research project involving the relationship between Danish number names and their corresponding digits in the canonical base 10 system. The project aims to develop a system to help the students’ understanding of the base 10 syste...

  10. Basic Stand Alone Carrier Line Items PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — This release contains the Basic Stand Alone (BSA) Carrier Line Items Public Use Files (PUF) with information from Medicare Carrier claims. The CMS BSA Carrier Line...

  11. Extending item response theory to online homework

    Directory of Open Access Journals (Sweden)

    Gerd Kortemeyer

    2014-05-01

    Full Text Available Item response theory (IRT becomes an increasingly important tool when analyzing “big data” gathered from online educational venues. However, the mechanism was originally developed in traditional exam settings, and several of its assumptions are infringed upon when deployed in the online realm. For a large-enrollment physics course for scientists and engineers, the study compares outcomes from IRT analyses of exam and homework data, and then proceeds to investigate the effects of each confounding factor introduced in the online realm. It is found that IRT yields the correct trends for learner ability and meaningful item parameters, yet overall agreement with exam data is moderate. It is also found that learner ability and item discrimination is robust over a wide range with respect to model assumptions and introduced noise. Item difficulty is also robust, but over a narrower range.

  12. Working memory for sequences of temporal durations reveals a volatile single-item store

    Directory of Open Access Journals (Sweden)

    Sanjay G Manohar

    2016-10-01

    Full Text Available When a sequence is held in working memory, different items are retained with differing fidelity. Here we ask whether a sequence of brief time intervals that must be remembered show recency effects, similar to those observed in verbal and visuospatial working memory. It has been suggested that prioritising some items over others can be accounted for by a focus of attention, maintaining some items in a privileged state. We therefore also investigated whether such benefits are vulnerable to disruption by attention or expectation. Participants listened to sequences of one to five tones, of varying durations (200ms to 2s. Subsequently, the length of one of the tones in the sequence had to be reproduced by holding a key. The discrepancy between the reproduced and actual durations quantified the fidelity of memory for auditory durations. Recall precision decreased with the number of items that had to be remembered, and was better for the first and last items of sequences, in line with set-size and serial position effects seen in other modalities. To test whether attentional filtering demands might impair performance, an irrelevant variation in pitch was introduced in some blocks of trials. In those blocks, memory precision was worse for sequences that consisted of only one item, i.e. the smallest memory set size. Thus, when irrelevant information was present, the benefit of having only one item in memory is attenuated. Finally we examined whether expectation could interfere with memory. On half the trials, the number of items in the upcoming sequence was cued. When the number of items was known in advance, performance was paradoxically worse when the sequence consisted of only one item. Thus the benefit of having only one item to remember is stronger when it is unexpectedly the only item. Our results suggest that similar mechanisms are used to hold auditory time durations in working memory, as for visual or verbal stimuli. Further, solitary items were

  13. Psychometric Properties of the Triarchic Psychopathy Measure: An Item Response Theory Approach.

    Science.gov (United States)

    Shou, Yiyun; Sellbom, Martin; Xu, Jing

    2017-02-06

    There is cumulative evidence for the cross-cultural validity of the Triarchic Psychopathy Measure (TriPM; Patrick, 2010) among non-Western populations. Recent studies using correlational and regression analyses show promising construct validity of the TriPM in Chinese samples. However, little is known about the efficiency of items in TriPM in assessing the proposed latent traits. The current study evaluated the psychometric properties of the Chinese TriPM at the item level using item response theory analyses. It also examined the measurement invariance of the TriPM between the Chinese and the U.S. student samples by applying differential item functioning analyses under the item response theory framework. The results supported the unidimensional nature of the Disinhibition and Meanness scales. Both scales had a greater level of precision in the respective underlying constructs at the positive ends. The two scales, however, had several items that were weakly associated with their respective latent traits in the Chinese student sample. Boldness, on the other hand, was found to be multidimensional, and reflected a more normally distributed range of variation. The examination of measurement bias via differential item functioning analyses revealed that a number of items of the TriPM were not equivalent across the Chinese and the U.S. Some modification and adaptation of items might be considered for improving the precision of the TriPM for Chinese participants. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  14. Refinement of the Brazilian Household Food Insecurity Measurement Scale: Recommendation for a 14-item EBIA

    Directory of Open Access Journals (Sweden)

    Ana Maria Segall-Corrêa

    2014-04-01

    Full Text Available OBJECTIVE: To review and refine Brazilian Household Food Insecurity Measurement Scale structure. METHODS: The study analyzed the impact of removing the item "adult lost weight" and one of two possibly redundant items on Brazilian Household Food Insecurity Measurement Scale psychometric behavior using the one-parameter logistic (Rasch model. Brazilian Household Food Insecurity Measurement Scale psychometric behavior was analyzed with respect to acceptable adjustment values ranging from 0.7 to 1.3, and to severity scores of the items with theoretically expected gradients. The socioeconomic and food security indicators came from the 2004 National Household Sample Survey, which obtained complete answers to Brazilian Household Food Insecurity Measurement Scale items from 112,665 households. RESULTS: Removing the items "adult reduced amount..." followed by "adult ate less..." did not change the infit of the remaining items, except for "adult lost weight", whose infit increased from 1.21 to 1.56. The internal consistency and item severity scores did not change when "adult ate less" and one of the two redundant items were removed. CONCLUSION: Brazilian Household Food Insecurity Measurement Scale reanalysis reduced the number of scale items from 16 to 14 without changing its internal validity. Its use as a nationwide household food security measure is strongly recommended.

  15. Investigating the Impact of Item Parameter Drift for Item Response Theory Models with Mixture Distributions

    Directory of Open Access Journals (Sweden)

    Yoon Soo ePark

    2016-02-01

    Full Text Available This study investigates the impact of item parameter drift (IPD on parameter and ability estimation when the underlying measurement model fits a mixture distribution, thereby violating the item invariance property of unidimensional item response theory (IRT models. An empirical study was conducted to demonstrate the occurrence of both IPD and an underlying mixture distribution using real-world data. Twenty-one trended anchor items from the 1999, 2003, and 2007 administrations of Trends in International Mathematics and Science Study (TIMSS were analyzed using unidimensional and mixture IRT models. TIMSS treats trended anchor items as invariant over testing administrations and uses pre-calibrated item parameters based on unidimensional IRT. However, empirical results showed evidence of two latent subgroups with IPD. Results showed changes in the distribution of examinee ability between latent classes over the three administrations. A simulation study was conducted to examine the impact of IPD on the estimation of ability and item parameters, when data have underlying mixture distributions. Simulations used data generated from a mixture IRT model and estimated using unidimensional IRT. Results showed that data reflecting IPD using mixture IRT model led to IPD in the unidimensional IRT model. Changes in the distribution of examinee ability also affected item parameters. Moreover, drift with respect to item discrimination and distribution of examinee ability affected estimates of examinee ability. These findings demonstrate the need to caution and evaluate IPD using a mixture IRT framework to understand its effect on item parameters and examinee ability.

  16. An Effective Multimedia Item Shell Design for Individualized Education: The Crome Project

    Directory of Open Access Journals (Sweden)

    Irene Cheng

    2008-01-01

    Full Text Available There are several advantages to creating multimedia item types and applying computer-based adaptive testing in education. First is the capability to motivate learning by making the learners feel more engaged and in an interactive environment. Second is a better concept representation, which is not possible in conventional multiple-choice tests. Third is the advantage of individualized curriculum design, rather than a curriculum designed for an average student. Fourth is a good choice of the next question, associated with the appropriate difficulty level based on a student's response to the current question. However, many issues need to be addressed when achieving these goals, including: (a the large number of item types required to represent the current multiple-choice questions in multimedia formats, (b the criterion used to determine the difficulty level of a multimedia question item, and (c the methodology applied to the question selection process for individual students. In this paper, we propose a multimedia item shell design that not only reduces the number of item types required, but also computes difficulty level of an item automatically. The concept of question seed is introduced to make content creation more cost-effective. The proposed item shell framework facilitates efficient communication between user responses at the client, and the scoring agents integrated with a student ability assessor at the server. We also describe approaches for automatically estimating difficulty level of questions, and discuss preliminary evaluation of multimedia item types by students.

  17. Calorie Changes in Chain Restaurant Menu Items: Implications for Obesity and Evaluations of Menu Labeling

    Science.gov (United States)

    Bleich, Sara N.; Wolfson, Julia A.; Jarlenski, Marian P.

    2014-01-01

    Background Supply-side reductions to the calories in chain restaurants are a possible benefit of upcoming menu labeling requirements. Purpose To describe trends in calories available in large U.S. restaurants. Methods Data were obtained from the MenuStat project, a census of menu items in 66 of the 100 largest U.S. restaurant chains, for 2012 and 2013 (N=19,417 items). Generalized linear models were used to calculate: (1) the mean change in calories from 2012 to 2013, among items on the menu in both years; and (2) the difference in mean calories, comparing newly introduced items to those on the menu in 2012 only (overall and between core versus non-core items). Data were analyzed in 2014. Results Mean calories among items on menus in both 2012 and 2013 did not change. Large restaurant chains in the U.S. have recently had overall declines in calories in newly introduced menu items (−56 calories, 12% decline). These declines were concentrated mainly in new main course items (−67 calories, 10% decline). New beverage (−26 calories, 8% decline) and children’s (−46 calories, 20% decline) items also had fewer mean calories. Among chain restaurants with a specific focus (e.g., burgers), average calories in new menu items not core to the business declined more than calories in core menu items. Conclusions Large chain restaurants significantly reduced the number of calories in newly introduced menu items. Supply-side changes to the calories in chain restaurants may have a significant impact on obesity prevention. PMID:25306397

  18. Calorie changes in chain restaurant menu items: implications for obesity and evaluations of menu labeling.

    Science.gov (United States)

    Bleich, Sara N; Wolfson, Julia A; Jarlenski, Marian P

    2015-01-01

    Supply-side reductions to the calories in chain restaurants are a possible benefit of upcoming menu labeling requirements. To describe trends in calories available in large U.S. restaurants. Data were obtained from the MenuStat project, a census of menu items in 66 of the 100 largest U.S. restaurant chains, for 2012 and 2013 (N=19,417 items). Generalized linear models were used to calculate (1) the mean change in calories from 2012 to 2013, among items on the menu in both years; and (2) the difference in mean calories, comparing newly introduced items to those on the menu in 2012 only (overall and between core versus non-core items). Data were analyzed in 2014. Mean calories among items on menus in both 2012 and 2013 did not change. Large restaurant chains in the U.S. have recently had overall declines in calories in newly introduced menu items (-56 calories, 12% decline). These declines were concentrated mainly in new main course items (-67 calories, 10% decline). New beverage (-26 calories, 8% decline) and children's (-46 calories, 20% decline) items also had fewer mean calories. Among chain restaurants with a specific focus (e.g., burgers), average calories in new menu items not core to the business declined more than calories in core menu items. Large chain restaurants significantly reduced the number of calories in newly introduced menu items. Supply-side changes to the calories in chain restaurants may have a significant impact on obesity prevention. Copyright © 2015 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  19. Calibration of the PROMIS physical function item bank in Dutch patients with rheumatoid arthritis.

    Directory of Open Access Journals (Sweden)

    Martijn A H Oude Voshaar

    Full Text Available OBJECTIVE: To calibrate the Dutch-Flemish version of the PROMIS physical function (PF item bank in patients with rheumatoid arthritis (RA and to evaluate cross-cultural measurement equivalence with US general population and RA data. METHODS: Data were collected from RA patients enrolled in the Dutch DREAM registry. An incomplete longitudinal anchored design was used where patients completed all 121 items of the item bank over the course of three waves of data collection. Item responses were fit to a generalized partial credit model adapted for longitudinal data and the item parameters were examined for differential item functioning (DIF across country, age, and sex. RESULTS: In total, 690 patients participated in the study at time point 1 (T2, N = 489; T3, N = 311. The item bank could be successfully fitted to a generalized partial credit model, with the number of misfitting items falling within acceptable limits. Seven items demonstrated DIF for sex, while 5 items showed DIF for age in the Dutch RA sample. Twenty-five (20% items were flagged for cross-cultural DIF compared to the US general population. However, the impact of observed DIF on total physical function estimates was negligible. DISCUSSION: The results of this study showed that the PROMIS PF item bank adequately fit a unidimensional IRT model which provides support for applications that require invariant estimates of physical function, such as computer adaptive testing and targeted short forms. More studies are needed to further investigate the cross-cultural applicability of the US-based PROMIS calibration and standardized metric.

  20. Plurality and number

    DEFF Research Database (Denmark)

    Kristoffersen, Jette Hedegaard; Lackner, Andrea

    2017-01-01

    Singularis is the marking of the noun if it refers to an entity only. Often languages distinguish between singularis and non-singularis. The term used for these two forms are singular and plural. While singular is generally the unmarked form, plural is usually marked. Depending on the morphosynta......Singularis is the marking of the noun if it refers to an entity only. Often languages distinguish between singularis and non-singularis. The term used for these two forms are singular and plural. While singular is generally the unmarked form, plural is usually marked. Depending...... on the morphosyntactic properties of the language under investigation, plural can be expressed on various lexical items such as nouns [Lexicon – Section 3.1], verbs [Lexicon – Section 3.2], adjectives [Lexicon – Section 3.4], number words [Lexicon – Section 3.10.1], quantifiers [Lexicon – Section 3.10.2] or classifier...

  1. Using Deterministic, Gated Item Response Theory Model to detect test cheating due to item compromise.

    Science.gov (United States)

    Shu, Zhan; Henson, Robert; Luecht, Richard

    2013-07-01

    The Deterministic, Gated Item Response Theory Model (DGM, Shu, Unpublished Dissertation. The University of North Carolina at Greensboro, 2010) is proposed to identify cheaters who obtain significant score gain on tests due to item exposure/compromise by conditioning on the item status (exposed or unexposed items). A "gated" function is introduced to decompose the observed examinees' performance into two distributions (the true ability distribution determined by examinees' true ability and the cheating distribution determined by examinees' cheating ability). Test cheaters who have score gain due to item exposure are identified through the comparison of the two distributions. Hierarchical Markov Chain Monte Carlo is used as the model's estimation framework. Finally, the model is applied in a real data set to illustrate how the model can be used to identify examinees having pre-knowledge on the exposed items.

  2. A strategy for optimizing item-pool management

    NARCIS (Netherlands)

    Ariel, A.; van der Linden, Willem J.; Veldkamp, Bernard P.

    2006-01-01

    Item-pool management requires a balancing act between the input of new items into the pool and the output of tests assembled from it. A strategy for optimizing item-pool management is presented that is based on the idea of a periodic update of an optimal blueprint for the item pool to tune item

  3. Loglinear multidimensional IRT models for polytomously scired Items

    NARCIS (Netherlands)

    Kelderman, Henk

    1988-01-01

    A loglinear item response theory (IRT) model is proposed that relates polytomously scored item responses to a multidimensional latent space. Each item may have a different response function where each item response may be explained by one or more latent traits. Item response functions may follow a

  4. Task Number and Cognitive Complexity as Determinants of Difficulty ...

    African Journals Online (AJOL)

    XY = 0.89. The three correlation coefficients is each significant (p < 0.05). Test constructors and users should include item task number and cognitive level in item analysis. These are testees or group of testees-independent and could be a bridge between CTT and IRT. Keywords: CTT, IRT, MCT, task number, cognitive level, ...

  5. Multidimensional CAT Item Selection Methods for Domain Scores and Composite Scores: Theory and Applications.

    Science.gov (United States)

    Yao, Lihua

    2012-07-01

    Multidimensional computer adaptive testing (MCAT) can provide higher precision and reliability or reduce test length when compared with unidimensional CAT or with the paper-and-pencil test. This study compared five item selection procedures in the MCAT framework for both domain scores and overall scores through simulation by varying the structure of item pools, the population distribution of the simulees, the number of items selected, and the content area. The existing procedures such as Volume (Segall in Psychometrika, 61:331-354, 1996), Kullback-Leibler information (Veldkamp & van der Linden in Psychometrika 67:575-588, 2002), Minimize the error variance of the linear combination (van der Linden in J. Educ. Behav. Stat. 24:398-412, 1999), and Minimum Angle (Reckase in Multidimensional item response theory, Springer, New York, 2009) are compared to a new procedure, Minimize the error variance of the composite score with the optimized weight, proposed for the first time in this study. The intent is to find an item selection procedure that yields higher precisions for both the domain and composite abilities and a higher percentage of selected items from the item pool. The comparison is performed by examining the absolute bias, correlation, test reliability, time used, and item usage. Three sets of item pools are used with the item parameters estimated from real live CAT data. Results show that Volume and Minimum Angle performed similarly, balancing information for all content areas, while the other three procedures performed similarly, with a high precision for both domain and overall scores when selecting items with the required number of items for each domain. The new item selection procedure has the highest percentage of item usage. Moreover, for the overall score, it produces similar or even better results compared to those from the method that selects items favoring the general dimension using the general model (Segall in Psychometrika 66:79-97, 2001); the

  6. AN EFFICIENT DATA MINING METHOD TO FIND FREQUENT ITEM SETS IN LARGE DATABASE USING TR- FCTM

    Directory of Open Access Journals (Sweden)

    Saravanan Suba

    2016-01-01

    Full Text Available Mining association rules in large database is one of most popular data mining techniques for business decision makers. Discovering frequent item set is the core process in association rule mining. Numerous algorithms are available in the literature to find frequent patterns. Apriori and FP-tree are the most common methods for finding frequent items. Apriori finds significant frequent items using candidate generation with more number of data base scans. FP-tree uses two database scans to find significant frequent items without using candidate generation. This proposed TR-FCTM (Transaction Reduction- Frequency Count Table Method discovers significant frequent items by generating full candidates once to form frequency count table with one database scan. Experimental results of TR-FCTM shows that this algorithm outperforms than Apriori and FP-tree.

  7. Item diagnostics in multivariate discrete data.

    Science.gov (United States)

    Maydeu-Olivares, Alberto; Liu, Yang

    2015-06-01

    Researchers who evaluate the fit of psychometric models to binary or multinomial items often look at univariate and bivariate residuals to determine how a poorly fitting model can be improved. There is a class of z statistics and also a class of generalized X₂ statistics that can be used for examining these marginal fits. We describe these statistics and compare them with regard to the control of Type I error and statistical power. We show how the class of z statistics can be extended to accommodate items with multinomial response options. We provide guidelines for the use of these statistics, including how to control for multiple testing, and present 2 detailed examples. Using the root mean square error of approximation (RMSEA) for discrete data to adjudge fit, the examples illustrate how the use of these methods can dramatically improve the fit of item response theory models to widely used measures in personality and clinical psychology. (c) 2015 APA, all rights reserved).

  8. Development and assessment of floor and ceiling items for the PROMIS physical function item bank.

    Science.gov (United States)

    Bruce, Bonnie; Fries, James; Lingala, Bharathi; Hussain, Yusra Nazar; Krishnan, Eswar

    2013-10-03

    Disability and Physical Function (PF) outcome assessment has had limited ability to measure functional status at the floor (very poor functional abilities) or the ceiling (very high functional abilities). We sought to identify, develop and evaluate new floor and ceiling items to enable broader and more precise assessment of PF outcomes for the NIH Patient-Reported-Outcomes Measurement Information System (PROMIS). We conducted two cross-sectional studies using NIH PROMIS item improvement protocols with expert review, participant survey and focus group methods. In Study 1, respondents with low PF abilities evaluated new floor items, and those with high PF abilities evaluated new ceiling items for clarity, importance and relevance. In Study 2, we compared difficulty ratings of new floor items by low functioning respondents and ceiling items by high functioning respondents to reference PROMIS PF-10 items. We used frequencies, percentages, means and standard deviations to analyze the data. In Study 1, low (n = 84) and high (n = 90) functioning respondents were mostly White, women, 70 years old, with some college, and disability scores of 0.62 and 0.30. More than 90% of the 31 new floor and 31 new ceiling items were rated as clear, important and relevant, leaving 26 ceiling and 30 floor items for Study 2. Low (n = 246) and high (n = 637) functioning Study 2 respondents were mostly White, women, 70 years old, with some college, and Health Assessment Questionnaire (HAQ) scores of 1.62 and 0.003. Compared to difficulty ratings of reference items, ceiling items were rated to be 10% more to greater than 40% more difficult to do, and floor items were rated to be about 12% to nearly 90% less difficult to do. These new floor and ceiling items considerably extend the measurable range of physical function at either extreme. They will help improve instrument performance in populations with broad functional ranges and those concentrated at one or the other extreme ends of

  9. Graphical modeling for item difficulty in medical faculty exams ...

    African Journals Online (AJOL)

    charts. Conclusion: The control charts have the advantage for classifying items as acceptable or unacceptable based on item difficulty criteria. Key words: Item difficulty, quality control, statistical process control, variable control charts ...

  10. Algorithmic test design using classical item parameters

    OpenAIRE

    van der Linden, Willem J.; Adema, Jos J.

    1988-01-01

    Two optimalization models for the construction of tests with a maximal value of coefficient alpha are given. Both models have a linear form and can be solved by using a branch-and-bound algorithm. The first model assumes an item bank calibrated under the Rasch model and can be used, for instance, when classical test theory has to serve as an interface between the item bank system and a user not familiar with modern test theory. Maximization of alpha was obtained by inserting a special constra...

  11. Manipulating the focus of attention in working memory: Evidence for a protection of multiple items against perceptual interference.

    Science.gov (United States)

    Barth, Anna; Schneider, Daniel

    2018-01-08

    Visual working memory representations can be shielded from interference by selective attentional focusing using retroactive cues (retro-cues). However, it is not clear how many representations can be effectively cued and which neural mechanisms provide the protection from distractors. To address these questions, we manipulated the number of attended items by means of a retro-cue (one, two, or three items) and presented a distractor display during the retention of information in working memory. Analyses of the raw error and a mixture model revealed that a general performance benefit was only present when one item was retro-cued. Nevertheless, a protection of the item representations against subsequent interference occurred also after a two-item cue. ERPs revealed a modulation of the posterior negative slow wave following the retro-cues, reflecting the applied working memory resources dependent on the number of attended representations. Further, the distractor information was encoded into working memory only when the number of attended items was not changed by the retro-cues (neutral and three-item conditions), reflected by a P3b following the distractor display. These results suggest that more than one item can be effectively protected from perceptual interference. We propose that the protective effect of selective attention within working memory is based on both a reduction of the number of focused representations and the attentional refreshing of item context and features. © 2018 Society for Psychophysiological Research.

  12. AVOID BECOMING A VICTIM OF COUNTERFEIT ITEMS

    Energy Technology Data Exchange (ETDEWEB)

    WARRINER RD

    2011-07-13

    In today's globalized economy, we cannot live without imported products. Most people do not realize how thin the safety net of regulation and inspection really is. Less than three percent of imported products receive any form of government inspection prior to sale. Avoid flea markets, street vendors and deep discount stores. The sellers of counterfeit wares know where to market their products. They look for individuals who are hungry for a brand name item but do not want to pay a brand name price for it. The internet provides anonymity to the sellers of counterfeit products. Unlike Europe, U.S. law does not hold internet-marketing organizations, responsible for the quality of the products sold on their websites. These organizations will remove an individual vendor when a sufficient number of complaints are lodged, but they will not take responsibility for the counterfeit products you may have purchased. EBay has a number of counterfeit product guides to help you avoid being a victim of the sellers of these products. Ten percent of all medications taken worldwide are counterfeit. If you do buy medications on-line, be sure that the National Association of Boards of Pharmacy Verified Internet Pharmacy Practice Sites (VIPPS) recommends the pharmacy you choose to use. Inspect all medication purchases and report any change in color, shape, imprinting or odor to your pharmacist. If you take generic medications these attributes may change from one manufacturer to another. Your pharmacist should inform you of any changes when you refill your prescription. If they do not, get clarification prior to taking the medication. Please note that the Federal Drug Administration (FDA) does not regulate supplements. The FDA only steps in when a specific supplement proves to cause physical harm or contains a regulated ingredient. Due to counterfeiting, Underwriters Laboratories (UL) changed their label design three times since 1996. The new gold label should be attached to the cord

  13. Food item use by coyote sex and age classes

    Energy Technology Data Exchange (ETDEWEB)

    Cypher, B.L.; Spencer, K.A.; Scrivner, J.H.

    1995-10-01

    Food item use by coyotes was compared between sexes and among age classes at the Naval Petroleum Reserves, California. Item use did not differ significantly between males and females. Although leporid was the item most frequently used by all age classes, item use differed significantly between pups (< 1 year), yearlings (1 year), and adults (> 1 year), probably due to differential use of secondary items. Variation in item use among age classes could potentially bias results of coyote food habit studies.

  14. Assessing Scientific Reasoning: A Comprehensive Evaluation of Item Features That Affect Item Difficulty

    Science.gov (United States)

    Stiller, Jurik; Hartmann, Stefan; Mathesius, Sabrina; Straube, Philipp; Tiemann, Rüdiger; Nordmeier, Volkhard; Krüger, Dirk; Upmeier zu Belzen, Annette

    2016-01-01

    The aim of this study was to improve the criterion-related test score interpretation of a text-based assessment of scientific reasoning competencies in higher education by evaluating factors which systematically affect item difficulty. To provide evidence about the specific demands which test items of various difficulty make on pre-service…

  15. A Comparison of the 27-Item and 12-Item Intolerance of Uncertainty Scales

    Science.gov (United States)

    Khawaja, Nigar G.; Yu, Lai Ngo Heidi

    2010-01-01

    The 27-item Intolerance of Uncertainty Scale (IUS) has become one of the most frequently used measures of Intolerance of Uncertainty. More recently, an abridged, 12-item version of the IUS has been developed. The current research used clinical (n = 50) and non-clinical (n = 56) samples to examine and compare the psychometric properties of both…

  16. Evaluating Item Discrimination Power of WHOQOL-BREF from an Item Response Model Perspectives

    Science.gov (United States)

    Lin, Ting Hsiang; Yao, Grace

    2009-01-01

    Quality of life (QOL) has become an important component of health. By using the methodology of psychometric theory, we examine the item properties of the WHOQOL-BRIEF. Samejima's graded response model with natural metrics of the logistic response function was fitted. The results showed items with negative natures were less discriminating. Items…

  17. Factor Analysis of Multidimensional Polytomous Item Response Data Suffering from Ignorable Item Nonresponse.

    Science.gov (United States)

    Bernaards A., Coen; Sijtsma, Klaas

    1999-01-01

    Used simulation to study the problem of missing item responses in tests and questionnaires when factor analysis is used to study the structure of the items. Factor loadings based on the EM algorithm best approximated the loading structure, with imputation of the mean per person across the scores for that person being the best alternative. (SLD)

  18. Modeling Local Item Dependence in Cloze and Reading Comprehension Test Items Using Testlet Response Theory

    Science.gov (United States)

    Baghaei, Purya; Ravand, Hamdollah

    2016-01-01

    In this study the magnitudes of local dependence generated by cloze test items and reading comprehension items were compared and their impact on parameter estimates and test precision was investigated. An advanced English as a foreign language reading comprehension test containing three reading passages and a cloze test was analyzed with a…

  19. Developing Multidimensional Likert Scales Using Item Factor Analysis: The Case of Four-Point Items

    Science.gov (United States)

    Asún, Rodrigo A.; Rdz-Navarro, Karina; Alvarado, Jesús M.

    2016-01-01

    This study compares the performance of two approaches in analysing four-point Likert rating scales with a factorial model: the classical factor analysis (FA) and the item factor analysis (IFA). For FA, maximum likelihood and weighted least squares estimations using Pearson correlation matrices among items are compared. For IFA, diagonally weighted…

  20. Le concept de banque d'items et ses implications sur le contenu didactique

    Science.gov (United States)

    Tistaert, G.; Mwene, Magabe

    1985-12-01

    The development of the concept of an item bank comes as a reply to the didactic situations which for reasons of efficiency require the storing of a number of susceptible items to be used at any time. Access to the computer makes possible an improvement and rationalization of the management of the item bank. At the same time the extension of the concept has followed two main directions. On the one hand, particular care relates to the adequacy of stored items with the content of learning and it brings about the emergence of a technology of item-editing. On the other hand, psychometric considerations have caused the invariance of essential characteristics of the items. This demands that the items respond to the presupposed models with latent traits. On the basis of theoretical arguments supported by some research findings the final part of the article calls attention to the deep discord among researchers concerning the reliability of the presuppositions of these models in the didactic field. The compromise will probably lead to it that the multidimensionality of items which have a didactic character are admitted.

  1. An emotional functioning item bank of 24 items for computerized adaptive testing (CAT) was established

    DEFF Research Database (Denmark)

    Petersen, Morten Aa.; Gamper, Eva-Maria; Costantini, Anna

    2016-01-01

    OBJECTIVE: To improve measurement precision, the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Group is developing an item bank for computerized adaptive testing (CAT) of emotional functioning (EF). The item bank will be within the conceptual framework...... of the widely used EORTC Quality of Life questionnaire (QLQ-C30). STUDY DESIGN AND SETTING: On the basis of literature search and evaluations by international samples of experts and cancer patients, 38 candidate items were developed. The psychometric properties of the items were evaluated in a large...... that 24 items could be included in a unidimensional IRT model. DIF did not seem to have any significant impact on the estimation of EF. Evaluations indicated that the CAT measure may reduce sample size requirements by up to 50% compared to the QLQ-C30 EF scale without reducing power. CONCLUSION...

  2. Dutch-Flemish translation of 17 item banks from the patient-reported outcomes measurement information system (PROMIS).

    Science.gov (United States)

    Terwee, C B; Roorda, L D; de Vet, H C W; Dekker, J; Westhovens, R; van Leeuwen, J; Cella, D; Correia, H; Arnold, B; Perez, B; Boers, M

    2014-08-01

    The Patient-Reported Outcomes Measurement Information System (PROMIS(®)) is a new, state-of-the-art assessment system for measuring patient-reported health and well-being of adults and children that has the potential to be more valid, reliable and responsive than existing PROMs. The PROMIS items can be administered in short forms or, more efficiently, through computerized adaptive testing. This paper describes the translation of 563 items from 17 PROMIS item banks (domains) for adults from the English source into Dutch-Flemish. The translation was performed by FACITtrans using standardized methodology and approved by the PROMIS Statistical Center. The translation included four forward translations, two back-translations, three to five independent reviews (at least two Dutch, one Flemish) and pre-testing in 70 adults (age range 20-77) from the Netherlands and Flanders. A small number of items required separate translations for Dutch and Flemish: physical function (five items), pain behaviour (two items), pain interference (one item), social isolation (one item) and global health (one item). Challenges faced in the translation process included: scarcity or overabundance of possible translations, unclear item descriptions, constructs broader/smaller in the target language, difficulties in rank ordering items, differences in unit of measurement, irrelevant items or differences in performance of activities. By addressing these challenges, acceptable translations were obtained for all items. The methodology used and experience gained in this study can be used as an example for researchers in other countries interested in translating PROMIS. The Dutch-Flemish PROMIS items are linguistically equivalent. Short forms will soon be available for use and entire item banks are ready for cross-cultural validation in the Netherlands and Flanders.

  3. A production inventory model with deteriorating items and shortages

    Directory of Open Access Journals (Sweden)

    Samanta G.P.

    2004-01-01

    Full Text Available A continuous production control inventory model for deteriorating items with shortages is developed. A number of structural properties of the inventory system are studied analytically. The formulae for the optimal average system cost, stock level, backlog level and production cycle time are derived when the deterioration rate is very small. Numerical examples are taken to illustrate the procedure of finding the optimal total inventory cost, stock level, backlog level and production cycle time. Sensitivity analysis is carried out to demonstrate the effects of changing parameter values on the optimal solution of the system.

  4. Aging and Confidence Judgments in Item Recognition

    Science.gov (United States)

    Voskuilen, Chelsea; Ratcliff, Roger; McKoon, Gail

    2018-01-01

    We examined the effects of aging on performance in an item-recognition experiment with confidence judgments. A model for confidence judgments and response time (RTs; Ratcliff & Starns, 2013) was used to fit a large amount of data from a new sample of older adults and a previously reported sample of younger adults. This model of confidence…

  5. Items of interest from recent ornithological literature

    African Journals Online (AJOL)

    hereby introduce a new feature for Scopus: Items of interest from recent ornithological literature. We hope to have this feature in all forthcoming issues of Scopus, switching between topics based on interest and articles received. Besides the Editorial Board occasionally soliciting articles, we welcome pieces from interested ...

  6. The Fantastic Four of Mathematics Assessment Items

    Science.gov (United States)

    Greenlees, Jane

    2011-01-01

    In this article, the author makes reference to four comic book characters to make the point that together they are a formidable team, but on their own they are vulnerable. She examines the four components of mathematics assessment items and the need for implicit instruction within the classroom for student success. Just like the "Fantastic Four"…

  7. Modeling the Discrimination Power of Physics Items

    Science.gov (United States)

    Mesic, Vanes

    2011-01-01

    For the purposes of tailoring physics instruction in accordance with the needs and abilities of the students it is useful to explore the knowledge structure of students of different ability levels. In order to precisely differentiate the successive, characteristic states of student achievement it is necessary to use test items that possess…

  8. Item-Specific Gender Differences in Confidence.

    Science.gov (United States)

    Foote, Chandra J.

    Very little research has been performed which examines gender differences in confidence in highly specified situations. More generalized studies consistently suggest that women are less confident than men (i.e. Sadker and Sadker, 1994). The few studies of gender differences in item-specific conditions indicate that men tend to be more confident in…

  9. Guide to Mathematics Released Items: Understanding Scoring

    Science.gov (United States)

    Partnership for Assessment of Readiness for College and Careers, 2017

    2017-01-01

    The Partnership for Assessment of Readiness for College and Careers (PARCC) mathematics items measure critical thinking, mathematical reasoning, and the ability to apply skills and knowledge to real-world problems. Students are asked to solve problems involving the key knowledge and skills for their grade level as identified by the Common Core…

  10. Algorithmic test design using classical item parameters

    NARCIS (Netherlands)

    van der Linden, Willem J.; Adema, Jos J.

    Two optimalization models for the construction of tests with a maximal value of coefficient alpha are given. Both models have a linear form and can be solved by using a branch-and-bound algorithm. The first model assumes an item bank calibrated under the Rasch model and can be used, for instance,

  11. Item Feature Effects in Evolution Assessment

    Science.gov (United States)

    Nehm, Ross H.; Ha, Minsu

    2011-01-01

    Despite concerted efforts by science educators to understand patterns of evolutionary reasoning in science students and teachers, the vast majority of evolution education studies have failed to carefully consider or control for item feature effects in knowledge measurement. Our study explores whether robust contextualization patterns emerge within…

  12. Guideline Implementation: Prevention of Retained Surgical Items.

    Science.gov (United States)

    Fencl, Jennifer L

    2016-07-01

    A surgical item unintentionally retained in a patient after an operative or other invasive procedure is a serious, preventable medical error with the potential to cause the patient great harm. Perioperative RNs play a key role in preventing retained surgical items (RSIs). The updated AORN "Guideline for prevention of retained surgical items" provides guidance for implementing a consistent, multidisciplinary approach to RSI prevention; accounting for surgical items; preventing retention of device fragments; reconciling count discrepancies; and using adjunct technologies to supplement manual count procedures. This article focuses on key points of the guideline to help perioperative personnel provide optimal care during a procedure. Key points addressed include taking responsibility for RSI prevention as a team; minimizing distractions, noise, and interruptions during counts; using consistent counting methods; reconciling discrepancies; and participating in performance-improvement activities. Perioperative RNs should review the complete guideline for additional information and for guidance in writing and updating policies and procedures. Copyright © 2016 AORN, Inc. Published by Elsevier Inc. All rights reserved.

  13. 47 CFR 32.7600 - Extraordinary items.

    Science.gov (United States)

    2010-10-01

    ... or Account 4110, Net current deferred nonoperating income taxes for the income tax effects (Federal... account shall also include the related income tax effect of the extraordinary items. (b) This account... Account 4070, Income taxes—accrued, shall be credited or charged for all current income tax effects...

  14. Local Development of Subject Area Item Banks.

    Science.gov (United States)

    Ward, Annie W.; Barlow, Gene

    1984-01-01

    It is feasible for school districts to develop and use subject area tests as reliable as those previously available only from commercial publishers. Three projects in local item development in a large school district are described. The first involved only Algebra 1. The second involved life science and career education at the elementary level; and…

  15. Subject-verb number (disagreement

    Directory of Open Access Journals (Sweden)

    Daniela Isac

    2010-01-01

    Full Text Available This paper discusses cases of number mismatches between subjects and verbs. The main proposal is that subject-verb agreement is not in number but in a different feature, that we call Cardinality. Cardinality is a feature of DPs that is computed on the basis of number features and collectivity features carried by various heads in the DP. The “computation” of the Cardinality feature proceeds internal to the feature matrix of one lexical item - the D. The values of the number and collectivity features carried by various heads in the DP are transferred to the D by means of a feature checking mechanism and the value of the Cardinality feature is then derived from these.

  16. 41 CFR 101-30.701-2 - Item standardization code.

    Science.gov (United States)

    2010-07-01

    ... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Item standardization code. 101-30.701-2 Section 101-30.701-2 Public Contracts and Property Management Federal Property Management....7-Item Reduction Program § 101-30.701-2 Item standardization code. Item standardization code (ISC...

  17. Empirical Appraisal of Items for Innovative Teacher Tests.

    Science.gov (United States)

    Sinclair, Norma; Pecheone, Raymond L.

    The impact of test item multidimensionality was examined as it affected fitting items on a teacher licensure test to an item response theory (IRT) model. Test item data from the 1990 study of G. W. Guiton and G. Delandshere are used. The Connecticut Elementary Certification Test (CONNECT) is a licensure examination designed to assess the subject…

  18. Latent and Manifest Monotonicity in Item Response Models.

    Science.gov (United States)

    Junker, Brian W.; Sijtsma, Klaas

    2000-01-01

    Presents results from two methods of evaluating monotonicity in item response models: regressing individual item scores on the total test score and on the "rest" score obtained by omitting the selected items from the total test score. Discusses implications for exploratory analysis of dichotomous item response data and the application of…

  19. 10 CFR 835.605 - Labeling items and containers.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Labeling items and containers. 835.605 Section 835.605... items and containers. Except as provided at § 835.606, each item or container of radioactive material... information to permit individuals handling, using, or working in the vicinity of the items or containers to...

  20. Defining Deficient Items by IRT Analysis of Calibration Data.

    Science.gov (United States)

    Krass, Iosif A.; Thomasson, Gary L.

    New items are being calibrated for the next generation of the computerized adaptive (CAT) version of the Armed Services Vocational Aptitude Battery (ASVAB) (Forms 5 and 6). The requirements that the items be "good" three-parameter logistic (3-PL) model items and typically "like" items in the previous CAT-ASVAB tests have…

  1. Differential Responses of Female Forgers to MMPI Items.

    Science.gov (United States)

    Owens, Robert G.; Harms, Laura O.

    1993-01-01

    Compared Minnesota Multiphasic Personality Inventory (MMPI) items for 128 females convicted of forgery against items for 128 females from age-matched normative sample. Thirty-three items were significant at 0.0001 level. Significant items were categorized as value system, relations with family, uncertainty, appearance of perfectionism,…

  2. Real-time learning of predictive recognition categories that chunk sequences of items stored in working memory

    Directory of Open Access Journals (Sweden)

    Stephen eGrossberg

    2014-10-01

    Full Text Available How are sequences of events that are temporarily stored in a cognitive working memory unitized, or chunked, through learning? Such sequential learning is needed by the brain in order to enable language, spatial understanding, and motor skills to develop. In particular, how does the brain learn categories, or list chunks, that become selectively tuned to different temporal sequences of items in lists of variable length as they are stored in working memory, and how does this learning process occur in real time? The present article introduces a neural model that simulates learning of such list chunks. In this model, sequences of items are temporarily stored in an Item-and-Order, or competitive queuing, working memory before learning categorizes them using a categorization network, called a Masking Field, which is a self-similar, multiple-scale, recurrent on-center off-surround network that can weigh the evidence for variable-length sequences of items as they are stored in the working memory through time. A Masking Field hereby activates the learned list chunks that represent the most predictive item groupings at any time, while suppressing less predictive chunks. In a network with a given number of input items, all possible ordered sets of these item sequences, up to a fixed length, can be learned with unsupervised or supervised learning. The self-similar multiple-scale properties of Masking Fields interacting with an Item-and-Order working memory provide a natural explanation of George Miller's Magical Number Seven and Nelson Cowan's Magical Number Four. The article explains why linguistic, spatial, and action event sequences may all be stored by Item-and-Order working memories that obey similar design principles, and thus how the current results may apply across modalities. Item-and-Order properties may readily be extended to Item-Order-Rank working memories in which the same item can be stored in multiple list positions, or ranks, as in the list

  3. 42 CFR 1001.801 - Failure of HMOs and CMPs to furnish medically necessary items and services.

    Science.gov (United States)

    2010-10-01

    ... entity failed to provide a large number or a variety of items or services; (ii) The failures occurred over a lengthy period of time; (iii) The entity's failure to provide a necessary item or service that... 42 Public Health 5 2010-10-01 2010-10-01 false Failure of HMOs and CMPs to furnish medically...

  4. Item Screening in Graphical Loglinear Rasch Models

    DEFF Research Database (Denmark)

    Kreiner, Svend; Christensen, Karl Bang

    2011-01-01

    In behavioural sciences, local dependence and DIF are common, and purification procedures that eliminate items with these weaknesses often result in short scales with poor reliability. Graphical loglinear Rasch models (Kreiner & Christensen, in Statistical Methods for Quality of Life Studies, ed....... by M. Mesbah, F.C. Cole & M.T. Lee, Kluwer Academic, pp. 187–203, 2002) where uniform DIF and uniform local dependence are permitted solve this dilemma by modelling the local dependence and DIF. Identifying loglinear Rasch models by a stepwise model search is often very time consuming, since...... the initial item analysis may disclose a great deal of spurious and misleading evidence of DIF and local dependence that has to disposed of during the modelling procedure. Like graphical models, graphical loglinear Rasch models possess Markov properties that are useful during the statistical analysis...

  5. An evaluation of computerized adaptive testing for general psychological distress: combining GHQ-12 and Affectometer-2 in an item bank for public mental health research.

    Science.gov (United States)

    Stochl, Jan; Böhnke, Jan R; Pickett, Kate E; Croudace, Tim J

    2016-05-20

    Recent developments in psychometric modeling and technology allow pooling well-validated items from existing instruments into larger item banks and their deployment through methods of computerized adaptive testing (CAT). Use of item response theory-based bifactor methods and integrative data analysis overcomes barriers in cross-instrument comparison. This paper presents the joint calibration of an item bank for researchers keen to investigate population variations in general psychological distress (GPD). Multidimensional item response theory was used on existing health survey data from the Scottish Health Education Population Survey (n = 766) to calibrate an item bank consisting of pooled items from the short common mental disorder screen (GHQ-12) and the Affectometer-2 (a measure of "general happiness"). Computer simulation was used to evaluate usefulness and efficacy of its adaptive administration. A bifactor model capturing variation across a continuum of population distress (while controlling for artefacts due to item wording) was supported. The numbers of items for different required reliabilities in adaptive administration demonstrated promising efficacy of the proposed item bank. Psychometric modeling of the common dimension captured by more than one instrument offers the potential of adaptive testing for GPD using individually sequenced combinations of existing survey items. The potential for linking other item sets with alternative candidate measures of positive mental health is discussed since an optimal item bank may require even more items than these.

  6. The numeracy understanding in medicine instrument: a measure of health numeracy developed using item response theory.

    Science.gov (United States)

    Schapira, Marilyn M; Walker, Cindy M; Cappaert, Kevin J; Ganschow, Pamela S; Fletcher, Kathlyn E; McGinley, Emily L; Del Pozo, Sam; Schauer, Carrie; Tarima, Sergey; Jacobs, Elizabeth A

    2012-01-01

    Health numeracy can be defined as the ability to understand and apply information conveyed with numbers, tables and graphs, probabilities, and statistics to effectively communicate with health care providers, take care of one's health, and participate in medical decisions. To develop the Numeracy Understanding in Medicine Instrument (NUMi) using item response theory scaling methods. A 20-item test was formed drawing from an item bank of numeracy questions. Items were calibrated using responses from 1000 participants and a 2-parameter item response theory model. Construct validity was assessed by comparing scores on the NUMi to established measures of print and numeric health literacy, mathematic achievement, and cognitive aptitude. Community and clinical populations in the Milwaukee and Chicago metropolitan areas. Twenty-nine percent of the 1000 respondents were Hispanic, 24% were non-Hispanic white, and 42% were non-Hispanic black. Forty-one percent had no more than a high school education. The mean score on the NUMi was 13.2 (s = 4.6) with a Cronbach α of 0.86. Difficulty and discrimination item response theory parameters of the 20 items ranged from -1.70 to 1.45 and 0.39 to 1.98, respectively. Performance on the NUMi was strongly correlated with the Wide Range Achievement Test-Arithmetic (0.73, P measure of the health numeracy construct.

  7. 17 CFR 260.7a-16 - Inclusion of items, differentiation between items and answers, omission of instructions.

    Science.gov (United States)

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Inclusion of items, differentiation between items and answers, omission of instructions. 260.7a-16 Section 260.7a-16 Commodity and... INDENTURE ACT OF 1939 Formal Requirements § 260.7a-16 Inclusion of items, differentiation between items and...

  8. Dissociating the neural correlates of intra-item and inter-item working-memory binding.

    Directory of Open Access Journals (Sweden)

    Carinne Piekema

    Full Text Available BACKGROUND: Integration of information streams into a unitary representation is an important task of our cognitive system. Within working memory, the medial temporal lobe (MTL has been conceptually linked to the maintenance of bound representations. In a previous fMRI study, we have shown that the MTL is indeed more active during working-memory maintenance of spatial associations as compared to non-spatial associations or single items. There are two explanations for this result, the mere presence of the spatial component activates the MTL, or the MTL is recruited to bind associations between neurally non-overlapping representations. METHODOLOGY/PRINCIPAL FINDINGS: The current fMRI study investigates this issue further by directly comparing intrinsic intra-item binding (object/colour, extrinsic intra-item binding (object/location, and inter-item binding (object/object. The three binding conditions resulted in differential activation of brain regions. Specifically, we show that the MTL is important for establishing extrinsic intra-item associations and inter-item associations, in line with the notion that binding of information processed in different brain regions depends on the MTL. CONCLUSIONS/SIGNIFICANCE: Our findings indicate that different forms of working-memory binding rely on specific neural structures. In addition, these results extend previous reports indicating that the MTL is implicated in working-memory maintenance, challenging the classic distinction between short-term and long-term memory systems.

  9. Differential Item Functioning (DIF) and Subsequent Bias in Group Comparisons using a Composite Measurement Scale: A Simulation Study.

    Science.gov (United States)

    Rouquette, Alexandra; Hardouin, Jean-Benoit; Coste, Joel

    To determine the conditions in which the estimation of a difference between groups for a construct evaluated using a composite measurement scale is biased if the presence of Differential Item Functioning (DIF) is not taken into account. Datasets were generated using the Partial Credit Model to simulate 642 realistic scenarios. The effect of seven factors on the bias on the estimated difference between groups was evaluated using ANOVA: sample size, true difference between groups, number of items in the scale, proportion of items showing DIF, DIF-size for these items, position of these items location parameters along the latent trait, and uniform/non-uniform DIF. For uniform DIF, only the DIF-size and the proportion of items showing DIF (and their interaction term) had meaningful effects. The effect of non-uniform DIF was negligible. The measurement bias resulting from DIF was quantified in various realistic conditions of composite measurement scale use.

  10. Optimal Buyer’s Replenishment Policy in the Integrated Inventory Model for Imperfect Items

    Directory of Open Access Journals (Sweden)

    Lu Yueli

    2016-01-01

    Full Text Available In the classical economic order quantity (EOQ models, a common unrealistic assumption is that all the items received are of good quality. However, in realistic environment, a received shipment usually contains a fraction of imperfect quality items. These imperfect items may be scrapped, reworked at a cost, or salvaged at a discounted price. While the percentage of imperfect items is random, the optimal ordering cycle is rarely considered in current literatures. This paper revisits the model (Maddah and Jaber, 2008 and extends it by assuming that the ordering cycle is determined by the demand rate, delivery quantity per shipment, and the mathematical expectation of the defective rate. The possibility of stockout or residue in the end of a cycle will be considered, and the loss of stockout and the salvage of the residue are counted into the cost. Besides, we consider consolidating the shipments of imperfect items over multiple deliveries. Thus, an integrated vendor-buyer inventory model for imperfect quality items with equal-size shipment policy is established to derive the optimal ordering cycle, ordering quantity, and number of deliveries. The computational method of the optimal delivery quantity per shipment and number of deliveries is given through theoretical results. Finally, sensitivity of main parameters is analyzed through simulation experiments and shown by some figures.

  11. Task Number and Cognitive Complexity as Determinants of Difficulty ...

    African Journals Online (AJOL)

    PROF. O. E. OSUAGWU

    2013-09-01

    Richardson formula 20 is 0.76. The scores of the sample of students to the items and the .... (viii) multiplying out. Task number = 8. Academics managing very large classes find MCT items an attractive option due to the ease of marking.

  12. The quadratic relationship between difficulty of intelligence test items and their correlations with working memory.

    Science.gov (United States)

    Smolen, Tomasz; Chuderski, Adam

    2015-01-01

    Fluid intelligence (Gf) is a crucial cognitive ability that involves abstract reasoning in order to solve novel problems. Recent research demonstrated that Gf strongly depends on the individual effectiveness of working memory (WM). We investigated a popular claim that if the storage capacity underlay the WM-Gf correlation, then such a correlation should increase with an increasing number of items or rules (load) in a Gf-test. As often no such link is observed, on that basis the storage-capacity account is rejected, and alternative accounts of Gf (e.g., related to executive control or processing speed) are proposed. Using both analytical inference and numerical simulations, we demonstrated that the load-dependent change in correlation is primarily a function of the amount of floor/ceiling effect for particular items. Thus, the item-wise WM correlation of a Gf-test depends on its overall difficulty, and the difficulty distribution across its items. When the early test items yield huge ceiling, but the late items do not approach floor, that correlation will increase throughout the test. If the early items locate themselves between ceiling and floor, but the late items approach floor, the respective correlation will decrease. For a hallmark Gf-test, the Raven-test, whose items span from ceiling to floor, the quadratic relationship is expected, and it was shown empirically using a large sample and two types of WMC tasks. In consequence, no changes in correlation due to varying WM/Gf load, or lack of them, can yield an argument for or against any theory of WM/Gf. Moreover, as the mathematical properties of the correlation formula make it relatively immune to ceiling/floor effects for overall moderate correlations, only minor changes (if any) in the WM-Gf correlation should be expected for many psychological tests.

  13. The quadratic relationship between difficulty of intelligence test items and their correlations with working memory

    Directory of Open Access Journals (Sweden)

    Tomasz eSmoleń

    2015-08-01

    Full Text Available Fluid intelligence (Gf is a crucial cognitive ability that involves abstract reasoning in order to solve novel problems. Recent research demonstrated that Gf strongly depends on the individual effectiveness of working memory (WM. We investigated a popular claim that if the storage capacity underlay the WM-Gf correlation, then such a correlation should increase with an increasing number of items or rules (load in a Gf test. As often no such link is observed, on that basis the storage-capacity account is rejected, and alternative accounts of Gf (e.g., related to executive control or processing speed are proposed. Using both analytical inference and numerical simulations, we demonstrated that the load-dependent change in correlation is primarily a function of the amount of floor/ceiling effect for particular items. Thus, the item-wise WM correlation of a Gf test depends on its overall difficulty, and the difficulty distribution across its items. When the early test items yield huge ceiling, but the late items do not approach floor, that correlation will increase throughout the test. If the early items locate themselves between ceiling and floor, but the late items approach floor, the respective correlation will decrease. For a hallmark Gf test, the Raven test, whose items span from ceiling to floor, the quadratic relationship is expected, and it was shown empirically using a large sample and two types of WMC tasks. In consequence, no changes in correlation due to varying WM/Gf load, or lack of them, can yield an argument for or against any theory of WM/Gf. Moreover, as the mathematical properties of the correlation formula make it relatively immune to ceiling/floor effects for overall moderate correlations, only minor changes (if any in the WM-Gf correlation should be expected for many psychological tests.

  14. Effect of the Existence of Brownfields on Selected Item Expenditure of Municipal Budgets

    Directory of Open Access Journals (Sweden)

    Endel Stanislav

    2017-06-01

    Full Text Available The existence of brownfields in an area results in a number of problems. Among others, economic problems are often mentioned. They are mainly connected with negative influence on urban economics, i.e. the total cost of construction and operation of the city. These increased costs are then naturally reflected in the budgets of municipalities burdened by the existence of brownfields. This paper presents the individual items of municipal budgets, which can be influenced by the existence of brownfields, and then examines on a practical example of six Czech towns whether any functional dependence can be found between these items and a number of brownfields in the municipalities.

  15. Pengendalian Persediaan Primary Items dalam Logistik Konstruksi

    Directory of Open Access Journals (Sweden)

    Lady Lisya

    2016-09-01

    Full Text Available Construction logistics are activities that consist of ordering, storage and transportation of materials of construction projects. Storage material is logistics activity that ensure the availability of materials in project site. Generally, material storage activities have been conducted at the project site. Logistics construction is aimed to support the project activities that the completion schedule has been set. Construction logistics issues is determining the schedule of ordering materials so that the project can be implemented on schedule. The purpose of research is to determine the optimum ordering period for the primary items on the main building structure construction and designing inventory control cards as a mechanism for monitoring procurement of materials. This research has been obtained optimal ordering period for the primary items of main building structure with elements of the work using Fixed Period Requirement method. Inventories were already meet the material requirement of each period. Material management has been conducted based grouping approach as many as 31 groups. In addition, this research has proposed the inventory control cards as an instrument for material procurement monitoring. The implications of inventory control cards are coordinate contracting parties with vendors to plan the replenishment  of materials to meet the work schedule. Further research can be developed with other aspects such as integrated material order system between contractors and vendors to consider the safety stock. In addition, the information system for planning material is an important consideration for construction projects with large scale so that the companies can plan primary items inventory and other materials in the projects completion more easily, quickly and accurately.

  16. The potential for nutritional components of food items used for enrichment of research animals to act as confounding variables in toxicology studies.

    Science.gov (United States)

    Cooper, Dale M

    2015-06-01

    Produce and other non-certified foods may be provided to laboratory animals for enrichment, but this practice can generate scientific concerns, particularly if these food items contain nutrients that are pharmacologically active or affect animals' consumption of the basal diet. The author reviews information on potential for a number of nutritional components of food items to affect study data. On the basis of published effect levels, he proposes an upper limit for the consumption of each component in enrichment items relative to the amount present in a standard basal diet. He then assesses the amounts of these nutritional components in a broad range of food enrichment items and proposes a maximum serving size for each item for several common laboratory animals. Total caloric content and sugar content are the limiting components for many enrichment food items, but most items may be used as enrichment for laboratory animals without affecting study results, as long as the amounts of the items provided are managed.

  17. Fuzzy stochastic inventory model for deteriorating item

    Directory of Open Access Journals (Sweden)

    Waliv Rahul H.

    2017-01-01

    Full Text Available A multi item profit maximization inventory model is developed in fuzzy stochastic environment. Demand is taken as Stock dependent demand. Available storage space is assumed to be imprecise and vague in nature. Impreciseness has been expressed by linear membership function. Purchasing cost and investment constraint are considered to be random and their randomness is expressed by normal distribution. The model has been formulated as a fuzzy stochastic programming problem and reduced to corresponding equivalent fuzzy linear programming problem. The model has been solved by using fuzzy linear programming technique and illustrated numerically.

  18. Finding Neural Assemblies with Frequent Item Set Mining

    Directory of Open Access Journals (Sweden)

    David ePicado-Muiño

    2013-05-01

    Full Text Available Cell assemblies, defined as groups of neurons exhibiting precise spike coordination, were proposed as a model of network processing in the cortex. Considerable progress made in recent years in multi-electrode technology enables to record massively parallel spike trains of hundred(s of neurons. Nevertheless, due to the challenges inherent in multivariate approaches, most studies favoring cortical cell assemblies still resorted to analyzing pairwise interactions. However, to recoverthe underlying correlation structures, higher-order correlations need to be identified directly. Inspired by the Accretion method (Gerstein et al. 1978 we propose a new assembly detection method based on frequent item set mining (FIM, which searches effectively and without redundancy for individual spike patterns that exceed a given support threshold. We study search methods, with which the space of potential cell assemblies may be explored, as well as test statistics and subsetconditions with which candidate assemblies may be assessed and filtered. It turns out that a core challenge of assembly detection is multiple testing, which causes a large number of false discoveries. Unfortunately, criteria that address individual candidate assemblies and try to assess them with statistical tests and/or subset conditions do not help much to tackle this problem. The core idea of our method is to shift the focus of statistical testing from specific assemblies (consisting of a specific set of neurons to spike patterns of a certain size (i.e. with a certain number of neurons. This significantly reduces the number of necessary tests, thus alleviating the multiple testing problem. We demonstrate that our method is able to reliably suppress false discoveries, while it is still very sensitive in discovering synchronous activity. Since we exploit high-speed computational techniques from frequent item set mining (FIM for the tests, our method is also computationally efficient.

  19. Reliability and validity of the Spanish version of the 10-item Connor-Davidson Resilience Scale (10-item CD-RISC in young adults

    Directory of Open Access Journals (Sweden)

    García-Campayo Javier

    2011-08-01

    Full Text Available Abstract Background The 10-item Connor-Davidson Resilience Scale (10-item CD-RISC is an instrument for measuring resilience that has shown good psychometric properties in its original version in English. The aim of this study was to evaluate the validity and reliability of the Spanish version of the 10-item CD-RISC in young adults and to verify whether it is structured in a single dimension as in the original English version. Findings Cross-sectional observational study including 681 university students ranging in age from 18 to 30 years. The number of latent factors in the 10 items of the scale was analyzed by exploratory factor analysis. Confirmatory factor analysis was used to verify whether a single factor underlies the 10 items of the scale as in the original version in English. The convergent validity was analyzed by testing whether the mean of the scores of the mental component of SF-12 (MCS and the quality of sleep as measured with the Pittsburgh Sleep Index (PSQI were higher in subjects with better levels of resilience. The internal consistency of the 10-item CD-RISC was estimated using the Cronbach α test and test-retest reliability was estimated with the intraclass correlation coefficient. The Cronbach α coefficient was 0.85 and the test-retest intraclass correlation coefficient was 0.71. The mean MCS score and the level of quality of sleep in both men and women were significantly worse in subjects with lower resilience scores. Conclusions The Spanish version of the 10-item CD-RISC showed good psychometric properties in young adults and thus can be used as a reliable and valid instrument for measuring resilience. Our study confirmed that a single factor underlies the resilience construct, as was the case of the original scale in English.

  20. Holding Multiple Items in Short Term Memory: A Neural Mechanism

    Science.gov (United States)

    Rolls, Edmund T.; Dempere-Marco, Laura; Deco, Gustavo

    2013-01-01

    Human short term memory has a capacity of several items maintained simultaneously. We show how the number of short term memory representations that an attractor network modeling a cortical local network can simultaneously maintain active is increased by using synaptic facilitation of the type found in the prefrontal cortex. We have been able to maintain 9 short term memories active simultaneously in integrate-and-fire simulations where the proportion of neurons in each population, the sparseness, is 0.1, and have confirmed the stability of such a system with mean field analyses. Without synaptic facilitation the system can maintain many fewer memories active in the same network. The system operates because of the effectively increased synaptic strengths formed by the synaptic facilitation just for those pools to which the cue is applied, and then maintenance of this synaptic facilitation in just those pools when the cue is removed by the continuing neuronal firing in those pools. The findings have implications for understanding how several items can be maintained simultaneously in short term memory, how this may be relevant to the implementation of language in the brain, and suggest new approaches to understanding and treating the decline in short term memory that can occur with normal aging. PMID:23613789

  1. Correlates of a Single-Item Indicator Versus a Multi-Item Scale of Outness About Same-Sex Attraction.

    Science.gov (United States)

    Wilkerson, J Michael; Noor, Syed W; Galos, Dylan L; Rosser, B R Simon

    2016-07-01

    In this study, we investigated if a single-item indicator measured the degree to which people were open about their same-sex attraction ("out") as accurately as a multi-item scale. For the multi-item scale, we used the Outness Inventory, which includes three subscales: family, world, and religion. We examined correlations between the single- and multi-item measures; between the single-item indicator and the subscales of the multi-item scale; and between the measures and internalized homonegativity, social attitudes towards homosexuality, and depressive symptoms. In addition, we calculated Tjur's R (2) as a measure of predictive power of the single-item indicator, multi-item scale, and subscales of the multi-item scale in predicting two health-related outcomes: depressive symptoms and condomless anal sex with multiple partners. There was a strong correlation between the single- and multi-item measures (r = 0.73). Furthermore, there were strong correlations between the single-item indicator and each subscale of the multi-item scale: family (r = 0.70), world (r = 0.77), and religion (r = 0.50). In addition, the correlations between the single-item indicator and internalized homonegativity (r = -0.63), social attitudes towards homosexuality (r = -0.38), and depression (r = -0.14) were higher than those between the multi-item scale and internalized homonegativity (r = -0.55), social attitudes towards homosexuality (r = -0.21), and depression (r = -0.13). Contrary to the premise that multi-item measures are superior to single-item measures, our collective findings indicate that the single-item indicator of outness performs better than the multi-item scale of outness.

  2. Correlates of a Single-Item Indicator Versus a Multi-Item Scale of Outness About Same-Sex Attraction

    Science.gov (United States)

    Noor, Syed W.; Galos, Dylan L.; Simon Rosser, B. R.

    2017-01-01

    In this study, we investigated if a single-item indicator measured the degree to which people were open about their same-sex attraction (“out”) as accurately as a multi-item scale. For the multi-item scale, we used the Outness Inventory, which includes three subscales: family, world, and religion. We examined correlations between the single- and multi-item measures; between the single-item indicator and the subscales of the multi-item scale; and between the measures and internalized homonegativity, social attitudes towards homosexuality, and depressive symptoms. In addition, we calculated Tjur’s R2 as a measure of predictive power of the single-item indicator, multi-item scale, and subscales of the multi-item scale in predicting two health-related outcomes: depressive symptoms and condomless anal sex with multiple partners. There was a strong correlation between the single- and multi-item measures (r = 0.73). Furthermore, there were strong correlations between the single-item indicator and each subscale of the multi-item scale: family (r = 0.70), world (r = 0.77), and religion (r = 0.50). In addition, the correlations between the single-item indicator and internalized homonegativity (r = −0.63), social attitudes towards homosexuality (r = −0.38), and depression (r = −0.14) were higher than those between the multi-item scale and internalized homonegativity (r = −0.55), social attitudes towards homosexuality (r = −0.21), and depression (r = −0.13). Contrary to the premise that multi-item measures are superior to single-item measures, our collective findings indicate that the single-item indicator of outness performs better than the multi-item scale of outness. PMID:26292840

  3. An analysis of the effects of the variety of items on the retailer's market areas and the urban system

    OpenAIRE

    Ishikawa, Toshiharu

    2013-01-01

    Due to the reduction of the transportation cost, the retailers become to be able to deal with many kinds of goods and to increase the number of items stocked at the stores. Corresponding to the increase of items stocked at stores, the customers tend to increase to visit the retailer that provides the more verities of goods. Hence, besides of the price of goods, the number of items at a store influences not only the retailer fs profits and its market area situation. Firstly, this paper incorp...

  4. Development of the PROMIS Social Motivations for Smoking item banks.

    Science.gov (United States)

    Tucker, Joan S; Shadel, William G; Edelen, Maria Orlando; Stucky, Brian D; Kuhfeld, Megan; Hansen, Mark; Cai, Li

    2014-09-01

    Smoking behavior is influenced by social motivations such as the expected social benefits of smoking and the social cues that induce craving. This paper describes development of the PROMIS Social Motivations for Smoking item banks, which will serve to standardize assessment of these social motivations among daily and nondaily smokers. Daily (N = 4,201) and nondaily (N =1,183) smokers completed an online survey. Item factor analyses, item response theory analyses, and differential item functioning analyses were conducted to identify a unidimensional set of items for each group. Short forms (SFs) and computer adaptive tests (CATs) were evaluated as tools for more efficiently assessing this construct. A total of 15 items were included in the item banks (9 items common to daily and nondaily smokers, 3 unique to daily, 3 unique to nondaily). Scores based on full item banks are highly reliable (reliability = 0.90-0.91). Additionally, the item banks are strongly unidimensional and perform similarly across gender, age, and race/ethnicity groups. A fixed SF for use with both daily and nondaily smokers consists of 4 items (reliability = 0.80). Results from simulated CATs showed that, on average, fewer than 5 items are needed to assess this construct with adequate precision using the item banks. A new set of items has been identified for assessing the social motivations for smoking in a reliable, standardized manner for daily and nondaily smokers. In addition to using the full item banks, efficient assessment can be achieved by using SFs, employing CATs, or selecting items tailored to specific research or clinical purposes. © The Author 2014. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Development and Design of a Dynamic Multimedia Item Generation Mechanism

    Science.gov (United States)

    Weng, Ting-Sheng

    2012-01-01

    This research applies multimedia technology to design a dynamic item generation method that can adaptively adjust the difficulty level of items according to the level of the testee. The method is based on interactive testing software developed by Flash Actionscript, and provides a testing solution for users by automatically distributing items of…

  6. DIF Detection and Effect Size Measures for Polytomously Scored Items

    Science.gov (United States)

    Kim, Seock-Ho; Cohen, Allan S.; Alagoz, Cigdem; Kim, Sukwoo

    2007-01-01

    Data from a large-scale performance assessment (N = 105,731) were analyzed with five differential item functioning (DIF) detection methods for polytomous items to examine the congruence among the DIF detection methods. Two different versions of the item response theory (IRT) model-based likelihood ratio test, the logistic regression likelihood…

  7. The 10-Item Substance Use Disorder Outcome Scale: Psychometric evaluation.

    Science.gov (United States)

    Westermeyer, Joseph; Yoon, Gihyun; Thuras, Paul; Batres-Y-Carr, Tegan; McNairy, Scott; Swanson, Heather

    2017-01-01

    The current study describes the psychometric properties of a scale (entitled "Substance Use Disorder Outcome Scale-10 items" or 10-Item Substance Use Disorder Outcome Scale) designed for longitudinal studies. Sixteen male veterans attending a substance use disorder recovery clinic were studied over a 2-year period. The attending nurse and physician conducted four, 10-Item Substance Use Disorder Outcome Scale scale ratings, each encompassing a 6-month period, for each participant. Analyses involved scale descriptive results, Cronbach alpha scores, effects of deleting the item on Cronbach alpha scores for the remaining items, and item-to-scale correlations across the four periods, plus three exploratory studies. Scale scores showed skewness p ≤ 1.0 and Cronbach alphas of 0.89 to 0.93. Six of 10 items correlated with total scale scores at 3 or 4 rating periods at p ≤ 0.005. Two items showed p ≤ 0.005 correlations only in the first two periods, and two items showed p ≤ 0.005 correlations only in the last two periods. Exploratory analyses revealed some item convergence over time plus non-significant associations with long-standing demographic and clinical variables. Desirable 10-Item Substance Use Disorder Outcome Scale psychometric properties included normal distribution, excellent Cronbach alphas, and high item-to-score correlations, all of which persisted over time.

  8. Optimal Test Design with Rule-Based Item Generation

    Science.gov (United States)

    Geerlings, Hanneke; van der Linden, Wim J.; Glas, Cees A. W.

    2013-01-01

    Optimal test-design methods are applied to rule-based item generation. Three different cases of automated test design are presented: (a) test assembly from a pool of pregenerated, calibrated items; (b) test generation on the fly from a pool of calibrated item families; and (c) test generation on the fly directly from calibrated features defining…

  9. Optimal test design with rule-based item generation

    NARCIS (Netherlands)

    Geerlings, Hanneke; van der Linden, Willem J.; Glas, Cornelis A.W.

    2013-01-01

    Optimal test-design methods are applied to rule-based item generation. Three different cases of automated test design are presented: (a) test assembly from a pool of pregenerated, calibrated items; (b) test generation on the fly from a pool of calibrated item families; and (c) test generation on the

  10. A Mixture Rasch Model with Item Response Time Components

    Science.gov (United States)

    Meyer, J. Patrick

    2010-01-01

    An examinee faced with a test item will engage in solution behavior or rapid-guessing behavior. These qualitatively different test-taking behaviors bias parameter estimates for item response models that do not control for such behavior. A mixture Rasch model with item response time components was proposed and evaluated through application to real…

  11. Guide to good practices for the development of test items

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-01

    While the methodology used in developing test items can vary significantly, to ensure quality examinations, test items should be developed systematically. Test design and development is discussed in the DOE Guide to Good Practices for Design, Development, and Implementation of Examinations. This guide is intended to be a supplement by providing more detailed guidance on the development of specific test items. This guide addresses the development of written examination test items primarily. However, many of the concepts also apply to oral examinations, both in the classroom and on the job. This guide is intended to be used as guidance for the classroom and laboratory instructor or curriculum developer responsible for the construction of individual test items. This document focuses on written test items, but includes information relative to open-reference (open book) examination test items, as well. These test items have been categorized as short-answer, multiple-choice, or essay. Each test item format is described, examples are provided, and a procedure for development is included. The appendices provide examples for writing test items, a test item development form, and examples of various test item formats.

  12. 31 CFR 50.14 - Separate line item.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Separate line item. 50.14 Section 50... PROGRAM Disclosures as Conditions for Federal Payment § 50.14 Separate line item. An insurer is deemed to be in compliance with the requirement of providing disclosure on a “separate line item in the policy...

  13. Mokken Scale Analysis for Dichotomous Items Using Marginal Models

    Science.gov (United States)

    van der Ark, L. Andries; Croon, Marcel A.; Sijtsma, Klaas

    2008-01-01

    Scalability coefficients play an important role in Mokken scale analysis. For a set of items, scalability coefficients have been defined for each pair of items, for each individual item, and for the entire scale. Hypothesis testing with respect to these scalability coefficients has not been fully developed. This study introduces marginal modelling…

  14. DIF Trees: Using Classification Trees to Detect Differential Item Functioning

    Science.gov (United States)

    Vaughn, Brandon K.; Wang, Qiu

    2010-01-01

    A nonparametric tree classification procedure is used to detect differential item functioning for items that are dichotomously scored. Classification trees are shown to be an alternative procedure to detect differential item functioning other than the use of traditional Mantel-Haenszel and logistic regression analysis. A nonparametric…

  15. Graphical modeling for item difficulty in medical faculty exams

    African Journals Online (AJOL)

    Conclusion: The control charts have the advantage for classifying items as acceptable or unacceptable based on item difficulty criteria. Key words: Item difficulty, quality control, statistical process control, variable control charts. Date of Acceptance: 26-Jun-2015. Address for correspondence: Dr. L Tomak,. Department of ...

  16. ASCAL: A Microcomputer Program for Estimating Logistic IRT Item Parameters.

    Science.gov (United States)

    Vale, C. David; Gialluca, Kathleen A.

    ASCAL is a microcomputer-based program for calibrating items according to the three-parameter logistic model of item response theory. It uses a modified multivariate Newton-Raphson procedure for estimating item parameters. This study evaluated this procedure using Monte Carlo Simulation Techniques. The current version of ASCAL was then compared to…

  17. Higher-Order Item Response Models for Hierarchical Latent Traits

    Science.gov (United States)

    Huang, Hung-Yu; Wang, Wen-Chung; Chen, Po-Hsi; Su, Chi-Ming

    2013-01-01

    Many latent traits in the human sciences have a hierarchical structure. This study aimed to develop a new class of higher order item response theory models for hierarchical latent traits that are flexible in accommodating both dichotomous and polytomous items, to estimate both item and person parameters jointly, to allow users to specify…

  18. A simple and fast item selection procedure for adaptive testing

    NARCIS (Netherlands)

    Veerkamp, W.J.J.; Veerkamp, Wim J.J.; Berger, Martijn; Berger, Martijn P.F.

    1994-01-01

    Items with the highest discrimination parameter values in a logistic item response theory (IRT) model do not necessarily give maximum information. This paper shows which discrimination parameter values (as a function of the guessing parameter and the distance between person ability and item

  19. The Development of Practical Item Analysis Program for Indonesian Teachers

    Science.gov (United States)

    Muhson, Ali; Lestari, Barkah; Supriyanto; Baroroh, Kiromim

    2017-01-01

    Item analysis has essential roles in the learning assessment. The item analysis program is designed to measure student achievement and instructional effectiveness. This study was aimed to develop item-analysis program and verify its feasibility. This study uses a Research and Development (R & D) model. The procedure includes designing and…

  20. 7 CFR 65.220 - Processed food item.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Processed food item. 65.220 Section 65.220 Agriculture..., PEANUTS, AND GINSENG General Provisions Definitions § 65.220 Processed food item. Processed food item... other covered commodity or other substantive food component (e.g., chocolate, breading, tomato sauce...

  1. Multistage Computerized Adaptive Testing with Uniform Item Exposure

    Science.gov (United States)

    Edwards, Michael C.; Flora, David B.; Thissen, David

    2012-01-01

    This article describes a computerized adaptive test (CAT) based on the uniform item exposure multi-form structure (uMFS). The uMFS is a specialization of the multi-form structure (MFS) idea described by Armstrong, Jones, Berliner, and Pashley (1998). In an MFS CAT, the examinee first responds to a small fixed block of items. The items comprising…

  2. Vegetable parenting practices scale: Item response modeling analyses

    Science.gov (United States)

    Our objective was to evaluate the psychometric properties of a vegetable parenting practices scale using multidimensional polytomous item response modeling which enables assessing item fit to latent variables and the distributional characteristics of the items in comparison to the respondents. We al...

  3. Verification of Differential Item Functioning (DIF) Status of West ...

    African Journals Online (AJOL)

    This study investigated test item bias and Differential Item Functioning (DIF) of West African Senior School Certificate Examination (WASSCE) in chemistry. The major objective was to examine how WASSCE items in chemistry function differentially with respect to gender and location. In Aba education zone of Abia, ...

  4. Examining differential item functioning due to difficulty and alternative attractiveness

    NARCIS (Netherlands)

    Westers, Paul; Kelderman, Henk

    1992-01-01

    A method for analyzing test item responses is proposed to examine differential item functioning (DIF) in multiple-choice items through a combination of the usual notion of DIF, for correct/incorrect responses and information about DIF contained in each of the alternatives. The proposed method uses

  5. A scale purification procedure for evaluation of differential item functioning

    NARCIS (Netherlands)

    Khalid, Muhammad Naveed; Glas, Cornelis A.W.

    2014-01-01

    Item bias or differential item functioning (DIF) has an important impact on the fairness of psychological and educational testing. In this paper, DIF is seen as a lack of fit to an item response (IRT) model. Inferences about the presence and importance of DIF require a process of so-called test

  6. 48 CFR 1852.246-73 - Human space flight item.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Human space flight item... 1852.246-73 Human space flight item. As prescribed in 1845.370(b), insert the following clause: Human Space Flight Item (MAR 1997) The Contractor shall include the following statement in all subcontracts...

  7. Borrowing and Loan Words: The Lemmatizing of Newly Acquired Lexical Items in Sesotho sa Leboa

    Directory of Open Access Journals (Sweden)

    V.M. Mojela

    2011-10-01

    Full Text Available

    ABSTRACT: The influence of foreign languages in Sesotho sa Leboa, or Northern Sotho, results in borrowing, which ultimately leads to an increase in the vocabulary of Sesotho sa Leboa. The languages influencing developments in the vocabulary of Sesotho sa Leboa include, inter alia, English, Afrikaans, Xitsonga, Tshivend√a and the Nguni languages. This article aims to give a critical analysis of the advantages and disadvantages of the adoption of foreign lexical items in the lemmatization of vocabulary in Sesotho sa Leboa dictionaries. Most puristic inclined academics and intellectuals are reluctant to adopt loan words as a means of developing the Sesotho sa Leboa vocabulary. When confronted with borrowing, the purists usually prefer coinage, using indigenous lexical items to name foreign concepts. This is disadvantageous to the development of the vocabulary of the language because (1 there is no increase in the number of the lexical items in the language since only the meanings of the foreign lexical item are added to existing indigenous lexical items, and (2 in most cases, previously adopted loan words are mistaken for indigenous lexical items and given preference to newly acquired lexical items which have direct and accurate bearing on the meaning of the newly discovered or designed concepts or objects.

    OPSOMMING: Ontlening en leenwoorde: Die lemmatisering van nuutverworwe leksikale items in Sesotho sa Leboa. Die invloed van vreemde tale op Sesotho sa Leboa, of Noord-Sotho, het ontlening tot gevolg, wat uiteindelik lei tot 'n toename in die woordeskat van Sesotho sa Leboa. Die tale wat ontwikkelinge in die woordeskat van Sesotho sa Leboa beïnvloed, sluit onder andere Engels, Afrikaans, Xitsonga, Tsivend√a en die Ngunitale in. Die doel van hierdie artikel is om 'n kritiese ontleding van die voordele en nadele van die oorneem van vreemde leksikale items by die lemmatisering van die woordeskat in woordeboeke van Sesotho sa Leboa te

  8. A Comparison of Methods for Nonparametric Estimation of Item Characteristic Curves for Binary Items

    Science.gov (United States)

    Lee, Young-Sun

    2007-01-01

    This study compares the performance of three nonparametric item characteristic curve (ICC) estimation procedures: isotonic regression, smoothed isotonic regression, and kernel smoothing. Smoothed isotonic regression, employed along with an appropriate kernel function, provides better estimates and also satisfies the assumption of strict…

  9. Detection of Uniform and Nonuniform Differential Item Functioning by Item-Focused Trees

    Science.gov (United States)

    Berger, Moritz; Tutz, Gerhard

    2016-01-01

    Detection of differential item functioning (DIF) by use of the logistic modeling approach has a long tradition. One big advantage of the approach is that it can be used to investigate nonuniform (NUDIF) as well as uniform DIF (UDIF). The classical approach allows one to detect DIF by distinguishing between multiple groups. We propose an…

  10. Item Discrimination and Type I Error in the Detection of Differential Item Functioning

    Science.gov (United States)

    Li, Yanju; Brooks, Gordon P.; Johanson, George A.

    2012-01-01

    In 2009, DeMars stated that when impact exists there will be Type I error inflation, especially with larger sample sizes and larger discrimination parameters for items. One purpose of this study is to present the patterns of Type I error rates using Mantel-Haenszel (MH) and logistic regression (LR) procedures when the mean ability between the…

  11. The Effect of Differential Item Functioning in Anchor Items on Population Invariance of Equating

    Science.gov (United States)

    Huggins, Anne Corinne

    2014-01-01

    Invariant relationships in the internal mechanisms of estimating achievement scores on educational tests serve as the basis for concluding that a particular test is fair with respect to statistical bias concerns. Equating invariance and differential item functioning are both concerned with invariant relationships yet are treated separately in the…

  12. Analysis of Item Response and Differential Item Functioning of Alcohol Expectancies in Middle School Youths

    Science.gov (United States)

    McCarthy, Denis M.; Pedersen, Sarah L.; D'Amico, Elizabeth J.

    2009-01-01

    Drinking behavior in preadolescence is a significant predictor of both short- and long-term negative consequences. This study examined the psychometric properties of 1 known risk factor for drinking in this age group, alcohol expectancies, within an item response theory framework. In a sample of middle school youths (N = 1,273), the authors tested…

  13. Factor- and Item-Level Analyses of the 38-Item Activities Scale for Kids-Performance

    Science.gov (United States)

    Bagley, Anita M.; Gorton, George E.; Bjornson, Kristie; Bevans, Katherine; Stout, Jean L.; Narayanan, Unni; Tucker, Carole A.

    2011-01-01

    Aim: Children and adolescents highly value their ability to participate in relevant daily life and recreational activities. The Activities Scale for Kids-performance (ASKp) instrument measures the frequency of performance of 30 common childhood activities, and has been shown to be valid and reliable. A revised and expanded 38-item ASKp (ASKp38)…

  14. Detecting a Gender-Related Differential Item Functioning Using Transformed Item Difficulty

    Science.gov (United States)

    Abedalaziz, Nabeel; Leng, Chin Hai; Alahmadi, Ahlam

    2014-01-01

    The purpose of the study was to examine gender differences in performance on multiple-choice mathematical ability test, administered within the context of high school graduation test that was designed to match eleventh grade curriculum. The transformed item difficulty (TID) was used to detect a gender related DIF. A random sample of 1400 eleventh…

  15. The effect of television news items on intimate partner violence murders.

    Science.gov (United States)

    Vives-Cases, C; Torrubiano-Domínguez, J; Alvarez-Dardet, C

    2009-12-01

    This study has been carried out in order to explore the effect of the growing appearance of IPV in television news items on deaths by this cause. Ecological study based on 340 deaths by intimate partner violence (IPV) and 3733 television news items covering this topic on Spanish television channels (2003 and 2007). Logistic regression analysis was carried out. Dependent variable: the difference between the number of IPV deaths in the 7 days following a news item broadcast and the number of IPV deaths in the 7 days before a media item. This outcome variable was conceptualised as a binary variable: increase vs. no increase. days with IPV news items-in general, concerning deaths, measures or other IPV crimes. Adjusted variables: day of the week, month, year and public holidays. A small copycat effect was observed in the IPV murder rate (RR = 1.32, CI(95%) = 1.07 - 1.62) for IPV-related news item days compared with days without such news. This effect continued when information about deaths was broadcast (RR = 1.28, CI(95%) = 1.01 - 1.62). News items concerning measures (RR = 0.90, CI(95%) = 0.82 - 0.98) or other IPV crimes (0.84, CI(95%) = 0.82 - 0.98) were related to a lower possibility of an increase in deaths compared with days with death-related news. Given the results observed in the case of IPV-related news, there is an evident need to develop a journalistic style guide in order to determine what type of information is recommended due to the potential positive or negative effects.

  16. Health equipment information, number 115, October 1983

    Energy Technology Data Exchange (ETDEWEB)

    1984-01-01

    Contents: Squibb Surgicare Ltd: System 2-Stoma Bridge for loop ostomy; Electronic and medical equipment: guidance on documentation required for maintenance; Assessment of the radio-opacity of catheters; IEC Publication number 731: dosimeters with ionization chambers as used in radiotherapy; Seminar on digital radiology; Economic appraisal of a Mobile CT Scanning Service; Equipment for the disabled; Evaluation of the Greiner G300 Analyser; Launch of Occupational Therapists' Reference Book 1983/4; Summary of health notices (hazard): 1 April 1983-31 August 1983; Safety Information Bulletin No 9-May 1983: Summary of items; Safety Information Bulletin No 10-July 1983: Summary of items; Safety Information Bulletin No 11-September 1983: Summary of items; Amendment to HEI 112 July 1983: evaluation of ECG Recorders.

  17. 17 CFR 229.1006 - (Item 1006) Purposes of the transaction and plans or proposals.

    Science.gov (United States)

    2010-04-01

    ..., SECURITIES EXCHANGE ACT OF 1934 AND ENERGY POLICY AND CONSERVATION ACT OF 1975-REGULATION S-K Mergers and Acquisitions (Regulation M-A) § 229.1006 (Item 1006) Purposes of the transaction and plans or proposals. (a... management of the subject company, including, but not limited to, any plans or proposals to change the number...

  18. Testing the Item-Order Account of Design Effects Using the Production Effect

    Science.gov (United States)

    Jonker, Tanya R.; Levene, Merrick; MacLeod, Colin M.

    2014-01-01

    A number of memory phenomena evident in recall in within-subject, mixed-lists designs are reduced or eliminated in between-subject, pure-list designs. The item-order account (McDaniel & Bugg, 2008) proposes that differential retention of order information might underlie this pattern. According to this account, order information may be encoded…

  19. Differential Item Functioning in Terms of Age in the Certificate in Advanced English Examination

    Science.gov (United States)

    Geranpayeh, Ardeshir; Kunnan, Antony John

    2007-01-01

    When standardized English-language tests are administered to test takers worldwide, the test-taking population could be varied on a number of personal and educational characteristics such as age, gender, first language, and academic discipline. As test tasks and test items may not always be prepared keeping this diversity of characteristics in…

  20. Are great apes able to reason from multi-item samples to populations of food items?

    Science.gov (United States)

    Eckert, Johanna; Rakoczy, Hannes; Call, Josep

    2017-10-01

    Inductive learning from limited observations is a cognitive capacity of fundamental importance. In humans, it is underwritten by our intuitive statistics, the ability to draw systematic inferences from populations to randomly drawn samples and vice versa. According to recent research in cognitive development, human intuitive statistics develops early in infancy. Recent work in comparative psychology has produced first evidence for analogous cognitive capacities in great apes who flexibly drew inferences from populations to samples. In the present study, we investigated whether great apes (Pongo abelii, Pan troglodytes, Pan paniscus, Gorilla gorilla) also draw inductive inferences in the opposite direction, from samples to populations. In two experiments, apes saw an experimenter randomly drawing one multi-item sample from each of two populations of food items. The populations differed in their proportion of preferred to neutral items (24:6 vs. 6:24) but apes saw only the distribution of food items in the samples that reflected the distribution of the respective populations (e.g., 4:1 vs. 1:4). Based on this observation they were then allowed to choose between the two populations. Results show that apes seemed to make inferences from samples to populations and thus chose the population from which the more favorable (4:1) sample was drawn in Experiment 1. In this experiment, the more attractive sample not only contained proportionally but also absolutely more preferred food items than the less attractive sample. Experiment 2, however, revealed that when absolute and relative frequencies were disentangled, apes performed at chance level. Whether these limitations in apes' performance reflect true limits of cognitive competence or merely performance limitations due to accessory task demands is still an open question. © 2017 Wiley Periodicals, Inc.

  1. The 12-item World Health Organization Disability Assessment Schedule II (WHO-DAS II: a nonparametric item response analysis

    Directory of Open Access Journals (Sweden)

    Fernandez Ana

    2010-05-01

    Full Text Available Abstract Background Previous studies have analyzed the psychometric properties of the World Health Organization Disability Assessment Schedule II (WHO-DAS II using classical omnibus measures of scale quality. These analyses are sample dependent and do not model item responses as a function of the underlying trait level. The main objective of this study was to examine the effectiveness of the WHO-DAS II items and their options in discriminating between changes in the underlying disability level by means of item response analyses. We also explored differential item functioning (DIF in men and women. Methods The participants were 3615 adult general practice patients from 17 regions of Spain, with a first diagnosed major depressive episode. The 12-item WHO-DAS II was administered by the general practitioners during the consultation. We used a non-parametric item response method (Kernel-Smoothing implemented with the TestGraf software to examine the effectiveness of each item (item characteristic curves and their options (option characteristic curves in discriminating between changes in the underliying disability level. We examined composite DIF to know whether women had a higher probability than men of endorsing each item. Results Item response analyses indicated that the twelve items forming the WHO-DAS II perform very well. All items were determined to provide good discrimination across varying standardized levels of the trait. The items also had option characteristic curves that showed good discrimination, given that each increasing option became more likely than the previous as a function of increasing trait level. No gender-related DIF was found on any of the items. Conclusions All WHO-DAS II items were very good at assessing overall disability. Our results supported the appropriateness of the weights assigned to response option categories and showed an absence of gender differences in item functioning.

  2. Vegetable parenting practices scale. Item response modeling analyses.

    Science.gov (United States)

    Chen, Tzu-An; O'Connor, Teresia M; Hughes, Sheryl O; Beltran, Alicia; Baranowski, Janice; Diep, Cassandra; Baranowski, Tom

    2015-08-01

    To evaluate the psychometric properties of a vegetable parenting practices scale using multidimensional polytomous item response modeling which enables assessing item fit to latent variables and the distributional characteristics of the items in comparison to the respondents. We also tested for differences in the ways item function (called differential item functioning) across child's gender, ethnicity, age, and household income groups. Parents of 3-5 year old children completed a self-reported vegetable parenting practices scale online. Vegetable parenting practices consisted of 14 effective vegetable parenting practices and 12 ineffective vegetable parenting practices items, each with three subscales (responsiveness, structure, and control). Multidimensional polytomous item response modeling was conducted separately on effective vegetable parenting practices and ineffective vegetable parenting practices. One effective vegetable parenting practice item did not fit the model well in the full sample or across demographic groups, and another was a misfit in differential item functioning analyses across child's gender. Significant differential item functioning was detected across children's age and ethnicity groups, and more among effective vegetable parenting practices than ineffective vegetable parenting practices items. Wright maps showed items only covered parts of the latent trait distribution. The harder- and easier-to-respond ends of the construct were not covered by items for effective vegetable parenting practices and ineffective vegetable parenting practices, respectively. Several effective vegetable parenting practices and ineffective vegetable parenting practices scale items functioned differently on the basis of child's demographic characteristics; therefore, researchers should use these vegetable parenting practices scales with caution. Item response modeling should be incorporated in analyses of parenting practice questionnaires to better assess

  3. SURFACE APPLICATION OF ANTIOZONANTS TO RUBBER ITEMS AND EVALUATION OF ANTIOZONANTS FOR PACKAGING RUBBER ITEMS IN PLASTIC BAGS

    Science.gov (United States)

    Research was conducted to develop methods of surface applications of antiozonants to rubber items and evaluate antiozonants for packaging rubber...items in plastic bags. The report covers (1) tests of packaging rubber items in polyethylene bags together with various antiozonants , and (2) tests of

  4. Confirmatory Factor Analysis of the M5-50: An Implementation of the International Personality Item Pool Item Set

    Science.gov (United States)

    Socha, Alan; Cooper, Christopher A.; McCord, David M.

    2010-01-01

    Goldberg's International Personality Item Pool (IPIP; Goldberg, 1999) provides researchers with public-domain, free-access personality measurement scales that are proxies of well-established published scales. One of the more commonly used IPIP sets employs 50 items to measure the 5 broad domains of the 5-factor model, with 10 items per factor. The…

  5. Do Images Influence Assessment in Anatomy? Exploring the Effect of Images on Item Difficulty and Item Discrimination

    Science.gov (United States)

    Vorstenbosch, Marc A. T. M.; Klaassen, Tim P. F. M.; Kooloos, Jan G. M.; Bolhuis, Sanneke M.; Laan, Roland F. J. M.

    2013-01-01

    Anatomists often use images in assessments and examinations. This study aims to investigate the influence of different types of images on item difficulty and item discrimination in written assessments. A total of 210 of 460 students volunteered for an extra assessment in a gross anatomy course. This assessment contained 39 test items grouped in…

  6. The Development of Practical Item Analysis Program for Indonesian Teachers

    Directory of Open Access Journals (Sweden)

    Ali Muhson

    2017-04-01

    Full Text Available Item analysis has essential roles in the learning assessment. The item analysis program is designed to measure student achievement and instructional effectiveness. This study was aimed to develop item-analysis program and verify its feasibility. This study uses a Research and Development (R & D model. The procedure includes designing and developing a product, validating, and testing the product. The data were collected through documentations, questionnaires, and interviews. This study successfully developed item analysis program, namely AnBuso. It is developed based on classical test theory (CTT. It was practical and applicable for Indonesian teachers to analyse test items

  7. The implications of content versus item validity on science tests

    Science.gov (United States)

    Yarroch, William L.

    The use of content validity as the primary assurance of the measurement accuracy for science assessment examinations is questioned. An alternative accuracy measure, item validity, is proposed. Item validity is based on research using qualitative comparisons between (a) student answers to objective items on the examination, (b) clinical interviews with examinees designed to ascertain their knowledge and understanding of the objective examination items, and (c) student answers to essay examination items prepared as an equivalent to the objective examination items. Calculations of item validity are used to show that selected objective items from the science assessment examination overestimated the actual student understanding of science content. Overestimation occurs when a student correctly answers an examination item, but for a reason other than that needed for an understanding of the content in question. There was little evidence that students incorrectly answered the items studied for the wrong reason, resulting in underestimation of the students' knowledge. The equivalent essay items were found to limit the amount of mismeasurement of the students' knowledge. Specific examples are cited and general suggestions are made on how to improve the measurement accuracy of objective examinations.

  8. Sources of interference in item and associative recognition memory.

    Science.gov (United States)

    Osth, Adam F; Dennis, Simon

    2015-04-01

    A powerful theoretical framework for exploring recognition memory is the global matching framework, in which a cue's memory strength reflects the similarity of the retrieval cues being matched against the contents of memory simultaneously. Contributions at retrieval can be categorized as matches and mismatches to the item and context cues, including the self match (match on item and context), item noise (match on context, mismatch on item), context noise (match on item, mismatch on context), and background noise (mismatch on item and context). We present a model that directly parameterizes the matches and mismatches to the item and context cues, which enables estimation of the magnitude of each interference contribution (item noise, context noise, and background noise). The model was fit within a hierarchical Bayesian framework to 10 recognition memory datasets that use manipulations of strength, list length, list strength, word frequency, study-test delay, and stimulus class in item and associative recognition. Estimates of the model parameters revealed at most a small contribution of item noise that varies by stimulus class, with virtually no item noise for single words and scenes. Despite the unpopularity of background noise in recognition memory models, background noise estimates dominated at retrieval across nearly all stimulus classes with the exception of high frequency words, which exhibited equivalent levels of context noise and background noise. These parameter estimates suggest that the majority of interference in recognition memory stems from experiences acquired before the learning episode. (c) 2015 APA, all rights reserved).

  9. Identifying Unbiased Items for Screening Preschoolers for Disruptive Behavior Problems.

    Science.gov (United States)

    Studts, Christina R; Polaha, Jodi; van Zyl, Michiel A

    2017-05-01

    Efficient identification and referral to behavioral services are crucial in addressing early-onset disruptive behavior problems. Existing screening instruments for preschoolers are not ideal for pediatric primary care settings serving diverse populations. Eighteen candidate items for a new brief screening instrument were examined to identify those exhibiting measurement bias (i.e., differential item functioning, DIF) by child characteristics. Parents/guardians of preschool-aged children ( N = 900) from four primary care settings completed two full-length behavioral rating scales. Items measuring disruptive behavior problems were tested for DIF by child race, sex, and socioeconomic status using two approaches: item response theory-based likelihood ratio tests and ordinal logistic regression. Of 18 items, eight were identified with statistically significant DIF by at least one method. The bias observed in 8 of 18 items made them undesirable for screening diverse populations of children. These items were excluded from the new brief screening tool.

  10. Item Response Theory with Covariates (IRT-C) : Assessing item recovery and differential item functioning for the three-parameter logistic model

    NARCIS (Netherlands)

    Tay, L.; Huang, Q.; Vermunt, J.K.

    2016-01-01

    In large-scale testing, the use of multigroup approaches is limited for assessing differential item functioning (DIF) across multiple variables as DIF is examined for each variable separately. In contrast, the item response theory with covariate (IRT-C) procedure can be used to examine DIF across

  11. A modular approach for item response theory modeling with the R package flirt.

    Science.gov (United States)

    Jeon, Minjeong; Rijmen, Frank

    2016-06-01

    The new R package flirt is introduced for flexible item response theory (IRT) modeling of psychological, educational, and behavior assessment data. flirt integrates a generalized linear and nonlinear mixed modeling framework with graphical model theory. The graphical model framework allows for efficient maximum likelihood estimation. The key feature of flirt is its modular approach to facilitate convenient and flexible model specifications. Researchers can construct customized IRT models by simply selecting various modeling modules, such as parametric forms, number of dimensions, item and person covariates, person groups, link functions, etc. In this paper, we describe major features of flirt and provide examples to illustrate how flirt works in practice.

  12. Production-inventory Management model for a weibull deteriorating item with linear demand and shortages

    Directory of Open Access Journals (Sweden)

    Gobinda Chandra Panda

    2013-06-01

    Full Text Available Background: Physical decay or deterioration of goods in stock is an important feature of real inventory systems. Material and methods: In the present paper, we discuss an production inventory model for a Weibull deteriorating item over a finite planning horizon with a linearly time-varying demand rate and a uniform production rate, allowing shortages, which are completely backlogged. Results and conclusions:  A production inventory model is developed for a Weibull deteriorating item over a finite planning horizon with a linear time varying demand, finite production rate and shortages. The optimal number of production cycles that minimizes the average system cost is determined.

  13. Development of an item bank for food parenting practices based on published instruments and reports from Canadian and US parents.

    Science.gov (United States)

    O'Connor, Teresia M; Pham, Truc; Watts, Allison W; Tu, Andrew W; Hughes, Sheryl O; Beauchamp, Mark R; Baranowski, Tom; Mâsse, Louise C

    2016-08-01

    Research to understand how parents influence their children's dietary intake and eating behaviors has expanded in the past decades and a growing number of instruments are available to assess food parenting practices. Unfortunately, there is no consensus on how constructs should be defined or operationalized, making comparison of results across studies difficult. The aim of this study was to develop a food parenting practice item bank with items from published scales and supplement with parenting practices that parents report using. Items from published scales were identified from two published systematic reviews along with an additional systematic review conducted for this study. Parents (n = 135) with children 5-12 years old from the US and Canada, stratified to represent the demographic distribution of each country, were recruited to participate in an online semi-qualitative survey on food parenting. Published items and parent responses were coded using the same framework to reduce the number of items into representative concepts using a binning and winnowing process. The literature contributed 1392 items and parents contributed 1985 items, which were reduced to 262 different food parenting concepts (26% exclusive from literature, 12% exclusive from parents, and 62% represented in both). Food parenting practices related to 'Structure of Food Environment' and 'Behavioral and Educational' were emphasized more by parent responses, while practices related to 'Consistency of Feeding Environment' and 'Emotional Regulation' were more represented among published items. The resulting food parenting item bank should next be calibrated with item response modeling for scientists to use in the future. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Defining value through quantity and quality-Chimpanzees (Pan troglodytes) undervalue food quantities when items are broken.

    Science.gov (United States)

    Parrish, Audrey E; Evans, Theodore A; Beran, Michael J

    2015-02-01

    Decision-making largely is influenced by the relative value of choice options, and the value of such options can be determined by a combination of different factors (e.g., the quantity, size, or quality of a stimulus). In this study, we examined the competing influences of quantity (i.e., the number of food items in a set) and quality (i.e., the original state of a food item) of choice items on chimpanzees' food preferences in a two-option natural choice paradigm. In Experiment 1, chimpanzees chose between sets of food items that were either entirely whole or included items that were broken into pieces before being shown to the chimpanzees. Chimpanzees exhibited a bias for whole food items even when such choice options consisted of a smaller overall quantity of food than the sets containing broken items. In Experiment 2, chimpanzees chose between sets of entirely whole food items and sets of initially whole items that were subsequently broken in view of the chimpanzees just before choice time. Chimpanzees continued to exhibit a bias for sets of whole items. In Experiment 3, chimpanzees chose between sets of new food items that were initially discrete but were subsequently transformed into a larger cohesive unit. Here, chimpanzees were biased to choose the discrete sets that retained their original qualitative state rather than toward the cohesive or clumped sets. These results demonstrate that beyond a food set's quantity (i.e., the value dimension that accounts for maximization in terms of caloric intake), other seemingly non-relevant features (i.e., quality in terms of a set's original state) affect how chimpanzees assign value to their choice options. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. The role of difficulty and gender in numbers, algebra, geometry and mathematics achievement

    Science.gov (United States)

    Rabab'h, Belal Sadiq Hamed; Veloo, Arsaythamby; Perumal, Selvan

    2015-05-01

    This study aims to identify the role of difficulty and gender in numbers, algebra, geometry and mathematics achievement among secondary schools students in Jordan. The respondent of the study were 337 students from eight public secondary school in Alkoura district by using stratified random sampling. The study comprised of 179 (53%) males and 158 (47%) females students. The mathematics test comprises of 30 items which has eight items for numbers, 14 items for algebra and eight items for geometry. Based on difficulties among male and female students, the findings showed that item 4 (fractions - 0.34) was most difficult for male students and item 6 (square roots - 0.39) for females in numbers. For the algebra, item 11 (inequality - 0.23) was most difficult for male students and item 6 (algebraic expressions - 0.35) for female students. In geometry, item 3 (reflection - 0.34) was most difficult for male students and item 8 (volume - 0.33) for female students. Based on gender differences, female students showed higher achievement in numbers and algebra compare to male students. On the other hand, there was no differences between male and female students achievement in geometry test. This study suggest that teachers need to give more attention on numbers and algebra when teaching mathematics.

  16. Are critical items "critical" for the MMPI-A.

    Science.gov (United States)

    Archer, R P; Jacobson, J M

    1993-12-01

    This article examines one aspect of the potential usefulness of critical items to the: Minnesota Multiphasic Personality Inventory -Adolescent (MMPI-A). Endorsement frequency data are presented on the Koss-Butcher (1973) and the Lachar-Wrobeli (1979) critical items for Minnesota Multiphasic Personality Inventory-2 (MMPI-2) adult normative and clinical samples and for MMPI-A adolescent normative and clinical samples. Adolescents in both normal and clinical samples endorse critical items with a higher frequency than do normal adults. Further, results demonstrated that significant differences were uniformly found between the endorsement frequencies for normative versus clinical subjects for the MMPI-2 samples, whereas similar comparisons for the MMPI-A samples typically showed that adolescents in clinical setting did not endorse critical items more frequently than normal adolescents. These findings indicate that it may be difficult to construct critical item lists for adolescents based on the type of empirical methodology used with adults in which items are selected based on endorsement frequency differences found between comparison group. Beyond the issue of the technical difficulty in creating a critical item list for adolescents, several conceptual concerns are raised regarding the application of critical items to the MMPI-A. It was noted that the concept of "critical items" has not been we11 defined, and both the reliability and validity of critical items may be limited in adolescent populations.

  17. A survey of theory and methods of invariant item ordering.

    Science.gov (United States)

    Sijtsma, K; Junker, B W

    1996-05-01

    In many testing situations, ordering the items by difficulty is helpful in analysing the testing data; examples include intelligence testing, analysis of differential item functioning, person-fit analysis, and exploring hypotheses about the order in which cognitive operations are acquired by children. In each situation, interpretation and analysis are made easier if the items are ordered by difficulty in the same way for every individual taking the test, i.e. the item response functions do not cross. This is an invariant item ordering. In this paper we review a class of non-parametric unidimensional item response models in which the ordinal properties of items (and persons) can be studied, and survey both old and new methods for the investigation of invariant item ordering in empirical data sets. Our model formulation derives in particular from the work of Holland & Rosenbaum (1986), Junker (1993) and Mokken (1971). We survey methods based on the work of Mokken (1971), Rosenbaum (1987a, b), and Sijtsma & Meijer (1992), and we also discuss some new proposals for checking invariant item ordering. When violations are detected, these methods allow a rough assessment of where on the latent scale the item response functions cross. We also study similarities and differences between these various methods and provide guidelines for their use. Finally, the methods are illustrated with data from a developmental psychology experiment in which the ability to draw inferences about transitive relations is explored.

  18. Editorial Changes and Item Performance: Implications for Calibration and Pretesting

    Directory of Open Access Journals (Sweden)

    Heather Stoffel

    2014-11-01

    Full Text Available Previous research on the impact of text and formatting changes on test-item performance has produced mixed results. This matter is important because it is generally acknowledged that any change to an item requires that it be recalibrated. The present study investigated the effects of seven classes of stylistic changes on item difficulty, discrimination, and response time for a subset of 65 items that make up a standardized test for physician licensure completed by 31,918 examinees in 2012. One of two versions of each item (original or revised was randomly assigned to examinees such that each examinee saw only two experimental items, with each item being administered to approximately 480 examinees. The stylistic changes had little or no effect on item difficulty or discrimination; however, one class of edits -' changing an item from an open lead-in (incomplete statement to a closed lead-in (direct question -' did result in slightly longer response times. Data for nonnative speakers of English were analyzed separately with nearly identical results. These findings have implications for the conventional practice of repretesting (or recalibrating items that have been subjected to minor editorial changes.

  19. Quantification of experienced hearing problems with item response theory.

    Science.gov (United States)

    Chenault, Michelene; Berger, Martijn; Kremer, Bernd; Anteunis, Lucien

    2013-12-01

    The purpose of this study was to improve the effectiveness of adult hearing screens and demonstrate that interventions assessment methods are needed that address the individual's experienced hearing. Item response theory, which provides a methodology for assessing patient-reported outcomes, is examined here to demonstrate its usefulness in hearing screens and interventions. The graded response model is applied to a scale of 11 items assessing perceived hearing functioning and 10 items assessing experienced social limitations completed by a sample of 212 persons age 55+ years. Fixed and variable slope models are compared. Discrimination and threshold parameters are estimated and information functions evaluated. Variable slope models for both scales provided the best fit. The estimated discrimination parameters for all items except for one in each scale were good if not excellent (1.5-3.4). Threshold values varied, demonstrating the complementary and supplementary value of items within a scale. The information provided by each item varies relative to trait values so that each scale of items provides information over a wider range of trait values. Item response theory methodology facilitates the comparison of items relative to their discriminative ability and information provided and thus provides a basis for the selection of items for application in a screening setting.

  20. A generalized sense of number.

    Science.gov (United States)

    Arrighi, Roberto; Togoli, Irene; Burr, David C

    2014-12-22

    Much evidence has accumulated to suggest that many animals, including young human infants, possess an abstract sense of approximate quantity, a number sense. Most research has concentrated on apparent numerosity of spatial arrays of dots or other objects, but a truly abstract sense of number should be capable of encoding the numerosity of any set of discrete elements, however displayed and in whatever sensory modality. Here, we use the psychophysical technique of adaptation to study the sense of number for serially presented items. We show that numerosity of both auditory and visual sequences is greatly affected by prior adaptation to slow or rapid sequences of events. The adaptation to visual stimuli was spatially selective (in external, not retinal coordinates), pointing to a sensory rather than cognitive process. However, adaptation generalized across modalities, from auditory to visual and vice versa. Adaptation also generalized across formats: adapting to sequential streams of flashes affected the perceived numerosity of spatial arrays. All these results point to a perceptual system that transcends vision and audition to encode an abstract sense of number in space and in time.

  1. Statistical power as a function of Cronbach alpha of instrument questionnaire items.

    Science.gov (United States)

    Heo, Moonseong; Kim, Namhee; Faith, Myles S

    2015-10-14

    In countless number of clinical trials, measurements of outcomes rely on instrument questionnaire items which however often suffer measurement error problems which in turn affect statistical power of study designs. The Cronbach alpha or coefficient alpha, here denoted by C(α), can be used as a measure of internal consistency of parallel instrument items that are developed to measure a target unidimensional outcome construct. Scale score for the target construct is often represented by the sum of the item scores. However, power functions based on C(α) have been lacking for various study designs. We formulate a statistical model for parallel items to derive power functions as a function of C(α) under several study designs. To this end, we assume fixed true score variance assumption as opposed to usual fixed total variance assumption. That assumption is critical and practically relevant to show that smaller measurement errors are inversely associated with higher inter-item correlations, and thus that greater C(α) is associated with greater statistical power. We compare the derived theoretical statistical power with empirical power obtained through Monte Carlo simulations for the following comparisons: one-sample comparison of pre- and post-treatment mean differences, two-sample comparison of pre-post mean differences between groups, and two-sample comparison of mean differences between groups. It is shown that C(α) is the same as a test-retest correlation of the scale scores of parallel items, which enables testing significance of C(α). Closed-form power functions and samples size determination formulas are derived in terms of C(α), for all of the aforementioned comparisons. Power functions are shown to be an increasing function of C(α), regardless of comparison of interest. The derived power functions are well validated by simulation studies that show that the magnitudes of theoretical power are virtually identical to those of the empirical power. Regardless

  2. Item response theory analysis applied to the Spanish version of the Personal Outcomes Scale.

    Science.gov (United States)

    Guàrdia-Olmos, J; Carbó-Carreté, M; Peró-Cebollero, M; Giné, C

    2017-11-01

    The study of measurements of quality of life (QoL) is one of the great challenges of modern psychology and psychometric approaches. This issue has greater importance when examining QoL in populations that were historically treated on the basis of their deficiency, and recently, the focus has shifted to what each person values and desires in their life, as in cases of people with intellectual disability (ID). Many studies of QoL scales applied in this area have attempted to improve the validity and reliability of their components by incorporating various sources of information to achieve consistency in the data obtained. The adaptation of the Personal Outcomes Scale (POS) in Spanish has shown excellent psychometric attributes, and its administration has three sources of information: self-assessment, practitioner and family. The study of possible congruence or incongruence of observed distributions of each item between sources is therefore essential to ensure a correct interpretation of the measure. The aim of this paper was to analyse the observed distribution of items and dimensions from the three Spanish POS information sources cited earlier, using the item response theory. We studied a sample of 529 people with ID and their respective practitioners and family member, and in each case, we analysed items and factors using Samejima's model of polytomic ordinal scales. The results indicated an important number of items with differential effects regarding sources, and in some cases, they indicated significant differences in the distribution of items, factors and sources of information. As a result of this analysis, we must affirm that the administration of the POS, considering three sources of information, was adequate overall, but a correct interpretation of the results requires that it obtain much more information to consider, as well as some specific items in specific dimensions. The overall ratings, if these comments are considered, could result in bias. © 2017

  3. A Study on the Systematization of Classification Process for NSG Trigger List Items

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Seunghyo; Tae, Jaewoong; Shin, Donghoon [Korea Institute of Nuclear Nonproliferation and Control/Nuclear Export Control Div., Daejeon (Korea, Republic of)

    2013-05-15

    In 1978, Nuclear Suppliers Group (NSG) was established to prevent nuclear items from being used for nuclear weapons. NSG drew up the NSG Guidelines (INFCIRC/254) that regulates export control items(so-called NSG trigger list items) and procedures. NSG recommends its member countries to reflect these guidelines on their export control systems and fulfill their obligations. Korea has carried out export controls on nuclear items by reflecting NSG Guidelines on Notice on Trade of Strategic Item of Foreign Trade Act since joining NSG in 1995. Nuclear export control starts with Classification that determines whether export items can be used for strategic items (goods and technologies that can be exclusively used for the manufacture, development and use of WMD). The standard of Classification is based on the NSG Guidelines. However, due to the qualitative characteristics of the Guidelines, there take place lots of difficulties in the Classification. Thus this study aims to suggest the systematic Classification process. Recently, the number of Classification requests is rapidly increasing due to the UAE commercial nuclear power plants and the Jordan reactors export. It is required to provide a more systematic Classification standard and process in order to provide an efficient and consistent Classification. Thus, this study analyzed limitations of EDP which causes difficulties in the process of classification due to its qualitative characteristics. Besides, it established systematic Classification process by quantitatively analyzing EDP. Consequently, it is expected that the results of this study will be used for as actual Classification. It still remains to establish a criterion of detailed information, which is one of the most important in the Classification for technology. Therefore, a further study will be conducted to establish a criterion of detailed information by analyzing Classification cases through the text mining techniques.

  4. The effectiveness of MMPI-A items in discriminating between normative and clinical samples.

    Science.gov (United States)

    Archer, R P; Handel, R W; Lynch, K D

    2001-12-01

    The Minnesota Multiphasic Personality Inventory-Adolescent (MMPI-A; Butcher et al., 1992) was released in 1992 and has rapidly become the most widely used objective personality assessment instrument with adolescents. Although the MMPI-A reduced or eliminated several problems associated with the use of the original MMPI (Hathaway & McKinley, 1943) with adolescents, the MMPI-A does produce a high frequency of within normal limits basic scale profiles for individuals with substantial psychopathology including adolescents in inpatient psychiatric settings. To better understand the reasons for this phenomenon, we compared the item endorsement frequencies for the MMPI-A normative sample with results from two adolescent clinical samples, and these results were contrasted to the item endorsement frequencies for the MMPI-2 (Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) normative sample and a clinical sample of adult psychiatric inpatients. Results showed that the MMPI-A contains a substantial number of items that do not show a significant difference in item endorsement frequency between normative and clinical samples. Furthermore, MMPI-A basic and content scales generally show a much lower percentage of effective items than do the corresponding scales for the MMPI-2. We discuss the findings in relation to the frequent occurrence of low range MMPI-A profiles in clinical samples and the potential usefulness of these results in future efforts to develop viable short forms for the MMPI-A.

  5. A Modified Apriori Algorithm for Fast and Accurate Generation of Frequent Item Sets

    Directory of Open Access Journals (Sweden)

    K.A.Baffour

    2017-08-01

    Full Text Available The Classical Apriori Algorithm CAA which is used for finding frequent item sets in Association Rule Mining consists of two main steps the join step for generating candidate item sets and the prune step for eliminating candidate item sets that are not frequent.The CAA despite its simplicity has some limitations the generation of a large number of candidate item sets the generation of many combinations that never occur in the database as well as the need to perform several full database scans when generating frequent item sets. In this research a Modified Apriori Algorithm MAA is proposed to address the problem of generating many combinations that never occur in the database by using a row-wise combination generation technique. A comparison of the results of the proposed algorithm against the Classical Apriori Algorithm shows that the proposed algorithm is faster and more efficient. The MAA was implemented on transaction databases and the results were compared against results from four 4 other Improved Apriori Algorithms for efficiency. The results of the comparative analysis showed that the MAA was more efficient in terms of execution time than the other Improved Apriori Algorithm.

  6. Inconsistency in the items included in tools used in general health research and physical therapy to evaluate the methodological quality of randomized controlled trials: a descriptive analysis

    OpenAIRE

    Armijo-Olivo, Susan; Fuentes, Jorge; Ospina, Maria; Saltaji, Humam; Hartling, Lisa

    2013-01-01

    Background Assessing the risk of bias of randomized controlled trials (RCTs) is crucial to understand how biases affect treatment effect estimates. A number of tools have been developed to evaluate risk of bias of RCTs; however, it is unknown how these tools compare to each other in the items included. The main objective of this study was to describe which individual items are included in RCT quality tools used in general health and physical therapy (PT) research, and how these items compare ...

  7. Memory of ordinal number categories in macaque monkeys.

    Science.gov (United States)

    Orlov, Tanya; Amit, Daniel J; Yakovlev, Volodya; Zohary, Ehud; Hochstein, Shaul

    2006-03-01

    What mechanism underlies serial order memory? Studying preverbal serial memory shows that macaque monkeys reproducing a sequence of items can acquire knowledge of item ordinal position. In our previous experiment, macaques were repeatedly presented with image lists (first shown sequentially and then simultaneously on a touch screen together with a distractor chosen randomly from other lists). The task was to touch list images in the correct order. The monkeys' natural tendency was to categorize images by their ordinal position or number because their most common error was touching the distractor when it had the same ordinal number (in its own list) as the correct image. Item-to-item associations were used to complete the categorization strategy. Proposing a dynamic image-salience hypothesis for serial recall (based on category-to-image influence and a salience computation for identifying touch targets), we now study the category label characteristics in the context of this hypothesis. We found that these category labels are absolute, ordinal-number-based categories (first, second, etc.), not relative memorized as relative distance from the beginning and the end of the list, and not based on fixed ranking of reward contingency/image familiarity. Even isolated from item-item associations, the categories demonstrate category tuning (as well as the corresponding overlap of adjacent ordinal number codes). Moreover, monkeys choose images by proximity of their category to the current touch number, irrespective of the accuracy of the preceding choice. Category tuning itself is symmetric relative to correct ordinal position, but is skewed by other factors (reward, etc.). Tuning width increases with list length, with a concurrent increased use of item-to-item associations for determining touch order.

  8. The basics of item response theory using R

    CERN Document Server

    Baker, Frank B

    2017-01-01

    This graduate-level textbook is a tutorial for item response theory that covers both the basics of item response theory and the use of R for preparing graphical presentation in writings about the theory. Item response theory has become one of the most powerful tools used in test construction, yet one of the barriers to learning and applying it is the considerable amount of sophisticated computational effort required to illustrate even the simplest concepts. This text provides the reader access to the basic concepts of item response theory freed of the tedious underlying calculations. It is intended for those who possess limited knowledge of educational measurement and psychometrics. Rather than presenting the full scope of item response theory, this textbook is concise and practical and presents basic concepts without becoming enmeshed in underlying mathematical and computational complexities. Clearly written text and succinct R code allow anyone familiar with statistical concepts to explore and apply item re...

  9. Modifying measures based on differential item functioning (DIF) impact analyses.

    Science.gov (United States)

    Teresi, Jeanne A; Ramirez, Mildred; Jones, Richard N; Choi, Seung; Crane, Paul K

    2012-09-01

    Measure modification can impact comparability of scores across groups and settings. Changes in items can affect the percent admitting to a symptom. Using item response theory (IRT) methods, well-calibrated items can be used interchangeably, and the exact same item does not have to be administered to each respondent, theoretically permitting wider latitude in terms of modification. Recommendations regarding modifications vary, depending on the use of the measure. In the context of research, adjustments can be made at the analytic level by freeing and fixing parameters based on findings of differential item functioning (DIF). The consequences of DIF for clinical decision making depend on whether or not the patient's performance level approaches the scale decision cutpoint. High-stakes testing may require item removal or separate calibrations to ensure accurate assessment. Guidelines for modification based on DIF analyses and illustrations of the impact of adjustments are presented.

  10. Effects of question formats on student and item performance.

    Science.gov (United States)

    Caldwell, David J; Pate, Adam N

    2013-05-13

    To determine the effect of 3 variations in test item format on item statistics and student performance. Fifteen pairs of directly comparable test questions were written to adhere to (standard scale) or deviate from (nonstandard scale) 3 specific item-writing guidelines. Differences in item difficulty and discrimination were measured between the 2 scales as a whole and for each guideline individually. Student performance was also compared between the 2 scales. The nonstandard scale was 12.7 points more difficult than the standard scale (p=0.03). The guideline to avoid "none of the above" was the only 1 of the 3 guidelines to demonstrate significance. Students scored 53.6% and 41.3% (pstudents to answer correctly than the standard test items, provided no enhanced ability to discriminate between higher- and lower-performing students, and resulted in poorer student performance. Item-writing guidelines should be considered during test construction.

  11. Scientific Items in Cyprus Turkish Tales

    Directory of Open Access Journals (Sweden)

    Sevilay Atmaca

    2013-05-01

    Full Text Available Folk literature, which is a production of daily life experiences transferred from mouth to mouth, encompasses many types such as epic, legend, folk poetry, mania, laments, songs, riddles, tales, folk story, anecdote, proverbs, idioms, rhymes, and etc. These products, which represent the oral tradition of the people, transfer numerous information regarding the life experiences, beliefs, and values of their communities to the next generation. Tales are more attractive since they depict extraordinary events and because of these characteristics they are very didactic. These are some reasons why tales have a very significant place in Turkish folk literature. People have documented tales successfully transferring from a nomadic life to a settled one. This study attempts to determine the scientific elements in Cyprus Turkish Tales, as sample in the scope of the Turkish Tales, through content analysis. Researchers in this study will examine the themes in the selected tales such as “Earth and Cosmos”, “Physical Event”, “Matter and Change”, and “Living Organisms and Life”. They will also provide a code-list according to the themes found in the tales. Researchers will do a content analysis in relation to the themes and code-listing activities in “Cyprus Turkish Tales” collected by Mustafa Gökçeoğlu, a well-known Cyprus Turkish folk literature writer. It is seen from the research that living organism and life (f: 25 and matter and change (f: 24 themes have very abundant coded. It is followed with an orderly physical events theme (f: 13 and earth and cosmos theme (f: 6. As a result, it is seen that in samples which are taken from Turkish Cypriot Tales, scientific items are widely used. It is believed that the results of the study will give different perspectives to Turkish Language, literature, science-technology, and classroom teacher providing them with interdisciplinary and rich materials.

  12. The Comparison between National Final Examination Test Items and English Teacher Made-Test Items of 2010 and 2011

    Directory of Open Access Journals (Sweden)

    Khairil Razali

    2015-02-01

    Full Text Available The objective of the paper is to determine the relevance between the scope of the national final examination test items in English lesson and the English teacher made test items. It is also to identify the relevance between the deepness of national final examination test items in English subject and the English teacher made test item. The finding showed that  more than fifty percents of tryout out test items are not relevant with the national test items. Meanwhile, the final national test items were design with higher cognitive domain than teacher made test items. It means the teacher made test items (tryout is more superficial than final national test items. It can be a reason why the students who are can pass the tryout test which is made in teacher cannot pass the national final examination test (standardized test. It is expected that this study provides empirical evidence to devise on their optimal uses in EFL teaching.  Copyright © 2015 by Al-Ta'lim All right reserved

  13. Algorithms for computerized test construction using classical item parameters

    OpenAIRE

    Adema, Jos J.; van der Linden, Willem J.

    1989-01-01

    Recently, linear programming models for test construction were developed. These models were based on the information function from item response theory. In this paper another approach is followed. Two 0-1 linear programming models for the construction of tests using classical item and test parameters are given. These models are useful, for instance, when classical test theory has to serve as an interface between an IRT-based item banking system and a test constructor not familiar with the und...

  14. Safety Evaluation for Packaging (onsite) T Plant Canyon Items

    Energy Technology Data Exchange (ETDEWEB)

    OBRIEN, J.H.

    2000-07-14

    This safety evaluation for packaging (SEP) evaluates and documents the ability to safely ship mostly unique inventories of miscellaneous T Plant canyon waste items (T-P Items) encountered during the canyon deck clean off campaign. In addition, this SEP addresses contaminated items and material that may be shipped in a strong tight package (STP). The shipments meet the criteria for onsite shipments as specified by Fluor Hanford in HNF-PRO-154, Responsibilities and Procedures for all Hazardous Material Shipments.

  15. Children, everyday numbers and school numbers

    Directory of Open Access Journals (Sweden)

    Clélia Maria Ignatius Nogueira

    2008-08-01

    Full Text Available Relationship made by school children between “daily” numbers, or rather, numbers deployed outside the school, and numbers worked out in school under various circumstances, or rather, orally and in writing, is investigated. Analysis has been undertaken with ten six-year-old children by means of a clinical and critical method. Research results show that children interact with the environment and recognized the figures, name them, conjecture on their written mode and give coherent meaning to the figures. Analysis also demonstrates that children use numbers outside the school. They understand and exemplify the number’s different meanings in an out-class context. Since the children do not give a weighty meaning to “school” numbers, pedagogical activity with numbers fails to put into practice the recommendations of the official policy.

  16. Three controversies over item disclosure in medical licensure examinations

    Directory of Open Access Journals (Sweden)

    Yoon Soo Park

    2015-09-01

    Full Text Available In response to views on public's right to know, there is growing attention to item disclosure – release of items, answer keys, and performance data to the public – in medical licensure examinations and their potential impact on the test's ability to measure competence and select qualified candidates. Recent debates on this issue have sparked legislative action internationally, including South Korea, with prior discussions among North American countries dating over three decades. The purpose of this study is to identify and analyze three issues associated with item disclosure in medical licensure examinations – 1 fairness and validity, 2 impact on passing levels, and 3 utility of item disclosure – by synthesizing existing literature in relation to standards in testing. Historically, the controversy over item disclosure has centered on fairness and validity. Proponents of item disclosure stress test takers’ right to know, while opponents argue from a validity perspective. Item disclosure may bias item characteristics, such as difficulty and discrimination, and has consequences on setting passing levels. To date, there has been limited research on the utility of item disclosure for large scale testing. These issues requires ongoing and careful consideration.

  17. Test equating in the presence of DIF items.

    Science.gov (United States)

    Chu, Kwang-lee; Kamata, Akihito

    2005-01-01

    This paper proposes a multilevel measurement model that controls for DIF effects in test equating. The accuracy and stability of item and ability parameter estimates under the proposed multilevel measurement model were examined using randomly simulated data. Estimates from the proposed model were compared with those resulting from two multiple-group concurrent equating designs, including 1) a design that replaced DIF-items with items with no DIF; and 2) a design that retained DIF items with no attempt to control for DIF. In most of the investigated conditions, the results indicated that the proposed multilevel measurement model performed better than the two comparison models.

  18. 16PF-E Structure using Radial Parcels Versus Items.

    Science.gov (United States)

    Hughey, Joseph; Burdsal, Charles

    1982-07-01

    The Sixteen Personality Factor Questionnaire (16PF) was factored with the use of groups of items called radial parcels and was subsequently compared with an item factoring of the same data. This was done in order to verify the 16PF (Form E) primary factors and to investigate the use of radial parcels in that process. Ss were 449 physically or mentally handicapped men and women who were part of a rehabilitation counseling process. Results indicated that with some familiar exceptions factor identification and verification were complete. Moreover, the use of radial parcels maintained the dimensionality found in the items. Also, rotation toward simple structure proceeded more rapidly with parcels than with items.

  19. Modeling answer changes on test items

    NARCIS (Netherlands)

    van der Linden, Willem J.

    2012-01-01

    The probability of test takers changing answers upon review of their initial choices is modeled. The primary purpose of the model is to check erasures on answer sheets recorded by an optical scanner for numbers and patterns that may be indicative of irregular behavior, such as teachers or school

  20. Eysenck Personality Inventory Item Factor Structure.

    Science.gov (United States)

    Comrey, Andrew L.; And Others

    1988-01-01

    Three methods were used to test the factor structure of the Eysenck Personality Inventory administered to 583 Australians. The preferred method was to extract factors by the minimum residual method, use the Tandem Criteria Method, and then rotate that number of factors by the Tandem Criteria I method. (SLD)

  1. Finding neural assemblies with frequent item set mining

    Science.gov (United States)

    Picado-Muiño, David; Borgelt, Christian; Berger, Denise; Gerstein, George; Grün, Sonja

    2013-01-01

    Cell assemblies, defined as groups of neurons exhibiting precise spike coordination, were proposed as a model of network processing in the cortex. Fortunately, in recent years considerable progress has been made in multi-electrode recordings, which enable recording massively parallel spike trains of hundred(s) of neurons simultaneously. However, due to the challenges inherent in multivariate approaches, most studies in favor of cortical cell assemblies still resorted to analyzing pairwise interactions. However, to recover the underlying correlation structures, higher-order correlations need to be identified directly. Inspired by the Accretion method proposed by Gerstein et al. (1978) we propose a new assembly detection method based on frequent item set mining (FIM). In contrast to Accretion, FIM searches effectively and without redundancy for individual spike patterns that exceed a given support threshold. We study different search methods, with which the space of potential cell assemblies may be explored, as well as different test statistics and subset conditions with which candidate assemblies may be assessed and filtered. It turns out that a core challenge of cell assembly detection is the problem of multiple testing, which causes a large number of false discoveries. Unfortunately, criteria that address individual candidate assemblies and try to assess them with statistical tests and/or subset conditions do not help much to tackle this problem. The core idea of our new method is that in order to cope with the multiple testing problem one has to shift the focus of statistical testing from specific assemblies (consisting of a specific set of neurons) to spike patterns of a certain size (i.e., with a certain number of neurons). This significantly reduces the number of necessary tests, thus alleviating the multiple testing problem. We demonstrate that our method is able to reliably suppress false discoveries, while it is still very sensitive in discovering

  2. Numbers Defy the Law of Large Numbers

    Science.gov (United States)

    Falk, Ruma; Lann, Avital Lavie

    2015-01-01

    As the number of independent tosses of a fair coin grows, the rates of heads and tails tend to equality. This is misinterpreted by many students as being true also for the absolute numbers of the two outcomes, which, conversely, depart unboundedly from each other in the process. Eradicating that misconception, as by coin-tossing experiments,…

  3. Behind the magical numbers: hierarchical chunking and the human working memory capacity.

    Science.gov (United States)

    Li, Guoqi; Ning, Ning; Ramanathan, Kiruthika; He, Wei; Pan, Li; Shi, Luping

    2013-08-01

    To explore the influence of chunking on the capacity limits of working memory, a model for chunking in sequential working memory is proposed, using hierarchical bidirectional inhibition-connected neural networks with winnerless competition. With the assumption of the existence of an upper bound to the inhibitory weights in neurobiological networks, it is shown that chunking increases the number of memorized items in working memory from the "magical number 7" to 16 items. The optimal number of chunks and the number of the memorized items in each chunk are the "magical number 4".

  4. Bibliography: Storage Stability of Semiperishable Subsistence Items

    Science.gov (United States)

    1993-04-01

    1972. 10 Corey, H., Texture in Foodstuffs, CRC Critical Reviews in Food Technology 1(2), 161-198, 1970. Delves-Broughton, J., Nisin and Its Uses as a...01760-5000 FOOD ENGINEERING DIRECTORATE 93 5 1?76 Reproduced From Best Available Copy DISCLAIMERS The findings contained in this report are not to be...under the work unit on Accelerated Testing, Project Number 1L162724AH99, Joint Services Food /Nutrition Technology, in the program entitled Food

  5. Expedited Return of Major Item Excess

    Science.gov (United States)

    1981-09-01

    by other documentation. The word "he" is intended to include both the masculine and feminine genders; any exception to this will be so noted...SEIRIAL NUMBER 3. NOUN NoMwCLAtUR 4. LINK NUNSERm S. 61O01.L NAT-ONAL STOCK NUMOSR 7. M A IN T EN WAN C A C T5V ITV a. U T IL IZ A T IO N " C O O S

  6. Number words and number symbols a cultural history of numbers

    CERN Document Server

    Menninger, Karl

    1992-01-01

    Classic study discusses number sequence and language and explores written numerals and computations in many cultures. "The historian of mathematics will find much to interest him here both in the contents and viewpoint, while the casual reader is likely to be intrigued by the author's superior narrative ability.

  7. Quantitative Analysis of Complex Multiple-Choice Items in Science Technology and Society: Item Scaling

    Directory of Open Access Journals (Sweden)

    Ángel Vázquez Alonso

    2005-05-01

    Full Text Available The scarce attention to assessment and evaluation in science education research has been especially harmful for Science-Technology-Society (STS education, due to the dialectic, tentative, value-laden, and controversial nature of most STS topics. To overcome the methodological pitfalls of the STS assessment instruments used in the past, an empirically developed instrument (VOSTS, Views on Science-Technology-Society have been suggested. Some methodological proposals, namely the multiple response models and the computing of a global attitudinal index, were suggested to improve the item implementation. The final step of these methodological proposals requires the categorization of STS statements. This paper describes the process of categorization through a scaling procedure ruled by a panel of experts, acting as judges, according to the body of knowledge from history, epistemology, and sociology of science. The statement categorization allows for the sound foundation of STS items, which is useful in educational assessment and science education research, and may also increase teachers’ self-confidence in the development of the STS curriculum for science classrooms.

  8. Item Response Theory: Introduction and Bibliography. Research Report No. 196.

    Science.gov (United States)

    Hambleton, Ronald K.

    A brief overview of item response theory is provided, and a 186-item bibliography of books and articles on the subject dating from 1953 to June 1989 is presented. The overview includes a definition of the theory, a discussion of its development and application, and comparisons with classical test theory. All publications in the bibliography were…

  9. 75 FR 71491 - Designation of Biobased Items for Federal Procurement

    Science.gov (United States)

    2010-11-23

    ..., and life- cycle costs of even a very small percentage of all products that may exist within an item... measures and life-cycle costs (the ASTM Standard D7075, ``Standard Practice for Evaluating and Reporting... health benefits, and life-cycle costs for each of the designated items. Information on the availability...

  10. 17 CFR 229.407 - (Item 407) Corporate governance.

    Science.gov (United States)

    2010-04-01

    ... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false (Item 407) Corporate governance. 229.407 Section 229.407 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION....407 (Item 407) Corporate governance. (a) Director independence. Identify each director and, when the...

  11. Mathematical-programming approaches to test item pool design

    NARCIS (Netherlands)

    Veldkamp, Bernard P.; van der Linden, Willem J.; Ariel, A.

    2002-01-01

    This paper presents an approach to item pool design that has the potential to improve on the quality of current item pools in educational and psychological testing andhence to increase both measurement precision and validity. The approach consists of the application of mathematical programming

  12. Item-Specific and Interitem Elaboration in Recall and Recognition

    Science.gov (United States)

    1984-07-01

    However, increasing task difficulty, resulting in a more istinctive encoding for items, plays a larger role in recognition. In a similar vein, Belleza ...and his collegues ( Belleza , Cheesman & Reddy 1977) have demonstrated that organizational strategies, such as the alphabet and story mnemonics, aid...specific semantic processing (Craik & Tulving, 1975). Presumably, some item-specific semantic processing occurs prior to or during organization ( Belleza

  13. Effects of Aging and IQ on Item and Associative Memory

    Science.gov (United States)

    Ratcliff, Roger; Thapar, Anjali; McKoon, Gail

    2011-01-01

    The effects of aging and IQ on performance were examined in 4 memory tasks: item recognition, associative recognition, cued recall, and free recall. For item and associative recognition, accuracy and the response time (RT) distributions for correct and error responses were explained by Ratcliff's (1978) diffusion model at the level of individual…

  14. Dissociation between source and item memory in Parkinson's disease.

    Science.gov (United States)

    Hu, Panpan; Li, Youhai; Ma, Huijuan; Xi, Chunhua; Chen, Xianwen; Wang, Kai

    2014-01-01

    Episodic memory includes information about item memory and source memory. Many researches support the hypothesis that these two memory systems are implemented by different brain structures. The aim of this study was to investigate the characteristics of item memory and source memory processing in patients with Parkinson's disease (PD), and to further verify the hypothesis of dual-process model of source and item memory. We established a neuropsychological battery to measure the performance of item memory and source memory. Totally 35 PD individuals and 35 matched healthy controls (HC) were administrated with the battery. Item memory task consists of the learning and recognition of high-frequency national Chinese characters; source memory task consists of the learning and recognition of three modes (character, picture, and image) of objects. Compared with the controls, the idiopathic PD patients have been impaired source memory (PD vs. HC: 0.65 ± 0.06 vs. 0.72 ± 0.09, P = 0.001), but not impaired in item memory (PD vs. HC: 0.65 ± 0.07 vs. 0.67 ± 0.08, P = 0.240). The present experiment provides evidence for dissociation between item and source memory in PD patients, thereby strengthening the claim that the item or source memory rely on different brain structures. PD patients show poor source memory, in which dopamine plays a critical role.

  15. Weighting of items in a tutorial performance evaluation instrument ...

    African Journals Online (AJOL)

    Weighting of items in an evaluation instrument contributes to more meaningful and valid interpretations of student performance in respect of each learning outcome or item being assessed. It follows that the validity of instruments is important for meaningful inferences about students' learning performance, including their ...

  16. A Statistical Test for Differential Item Pair Functioning

    NARCIS (Netherlands)

    Bechger, T.M.; Maris, G.

    This paper presents an IRT-based statistical test for differential item functioning (DIF). The test is developed for items conforming to the Rasch (Probabilistic models for some intelligence and attainment tests, The Danish Institute of Educational Research, Copenhagen, 1960) model but we will

  17. Algorithms for computerized test construction using classical item parameters

    NARCIS (Netherlands)

    Adema, Jos J.; van der Linden, Willem J.

    1989-01-01

    Recently, linear programming models for test construction were developed. These models were based on the information function from item response theory. In this paper another approach is followed. Two 0-1 linear programming models for the construction of tests using classical item and test

  18. Using response times for item selection in adaptive testing

    NARCIS (Netherlands)

    van der Linden, Willem J.

    2008-01-01

    Response times on items can be used to improve item selection in adaptive testing provided that a probabilistic model for their distribution is available. In this research, the author used a hierarchical modeling framework with separate first-level models for the responses and response times and a

  19. Limited Nomination Reliability Using Single- and Multiple-item Measures

    NARCIS (Netherlands)

    Babcock, B.; Marks, P.E.L.; Crick, N.R.; Cillessen, A.H.N.

    2014-01-01

    This article examines a variety of reliability issues as related to limited nomination sociometric measures. Peer nomination data were collected from 77 sixth grade classrooms. Results showed that, although some single-item peer nomination measures were relatively reliable, many single-item peer

  20. A person fit test for IRT models for polytomous items

    NARCIS (Netherlands)

    Glas, Cornelis A.W.; Dagohoy, A.V.

    2007-01-01

    A person fit test based on the Lagrange multiplier test is presented for three item response theory models for polytomous items: the generalized partial credit model, the sequential model, and the graded response model. The test can also be used in the framework of multidimensional ability

  1. Editorial Changes and Item Performance: Implications for Calibration and Pretesting

    Science.gov (United States)

    Stoffel, Heather; Raymond, Mark R.; Bucak, S. Deniz; Haist, Steven A.

    2014-01-01

    Previous research on the impact of text and formatting changes on test-item performance has produced mixed results. This matter is important because it is generally acknowledged that "any" change to an item requires that it be recalibrated. The present study investigated the effects of seven classes of stylistic changes on item…

  2. Elu kui näitemäng / Helju Koger

    Index Scriptorium Estoniae

    Koger, Helju, 1943-

    2007-01-01

    VI kihelkonnapäevadest Juurus. Juuru Mihkli kirikus esines ansambel Resonabilis. Konverentsil räägiti Järlepa mõisast, Anu Allikvee pidas ettekande "August von Kotzebue elu nagu näitemäng" jm. Näitemängu "Pärmi Jaagu unenägu" nägi kohalike asjaarmastajate esituses

  3. A Primer on Ways To Explore Item Bias.

    Science.gov (United States)

    Cromwell, Susan

    This paper provides an introductory primer on methods for exploring item bias. The purposes of item bias analysis are to investigate whether test scores are affected by different sources of variance in the various subpopulations, and if different sources of variance are found, to determine if an unfair advantage exists. The review discusses three…

  4. 38 CFR 59.90 - Line item adjustments to grants.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Line item adjustments to grants. 59.90 Section 59.90 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS (CONTINUED) GRANTS TO STATES FOR CONSTRUCTION OR ACQUISITION OF STATE HOMES § 59.90 Line item adjustments to...

  5. Creating a Database for Test Items in National Examinations (pp ...

    African Journals Online (AJOL)

    Nekky Umera

    vested on computer programmers and the labour turnover of programming staff was usually very high. The implication of this ..... test items banking; skills in test development, test moderation, item analysis with a good programming practice are ..... “A Web-based System for Automatic Language Skill. Assessment: EVALING”.

  6. Nested Logit Models for Multiple-Choice Item Response Data

    Science.gov (United States)

    Suh, Youngsuk; Bolt, Daniel M.

    2010-01-01

    Nested logit item response models for multiple-choice data are presented. Relative to previous models, the new models are suggested to provide a better approximation to multiple-choice items where the application of a solution strategy precedes consideration of response options. In practice, the models also accommodate collapsibility across all…

  7. Data Visualization of Item-Total Correlation by Median Smoothing

    Science.gov (United States)

    Yu, Chong Ho; Douglas, Samantha; Lee, Anna; An, Min

    2016-01-01

    This paper aims to illustrate how data visualization could be utilized to identify errors prior to modeling, using an example with multi-dimensional item response theory (MIRT). MIRT combines item response theory and factor analysis to identify a psychometric model that investigates two or more latent traits. While it may seem convenient to…

  8. Studies on statistical models for polytomously scored test items

    NARCIS (Netherlands)

    Akkermans, Wies

    1998-01-01

    This dissertation, which is structured as a collection of self-contained papers, will be concerned mainly with di�erences between item response models. The purpose of item response theory (IRT) is estimation of a hypothesized latent variable, such as, for example, intelligence or ability in

  9. 17 CFR 229.406 - (Item 406) Code of ethics.

    Science.gov (United States)

    2010-04-01

    ... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false (Item 406) Code of ethics. 229... 406) Code of ethics. (a) Disclose whether the registrant has adopted a code of ethics that applies to... code of ethics, explain why it has not done so. (b) For purposes of this Item 406, the term code of...

  10. Machine-Scored Testing, Part II: Creativity and Item Analysis.

    Science.gov (United States)

    Leuba, Richard J.

    1986-01-01

    Explains how multiple choice test items can be devised to measure higher-order learning, including engineering problem solving. Discusses the value and information provided in item analysis procedures with machine-scored tests. Suggests elements to consider in test design. (ML)

  11. Semiparametric Item Response Functions in the Context of Guessing

    Science.gov (United States)

    Falk, Carl F.; Cai, Li

    2016-01-01

    We present a logistic function of a monotonic polynomial with a lower asymptote, allowing additional flexibility beyond the three-parameter logistic model. We develop a maximum marginal likelihood-based approach to estimate the item parameters. The new item response model is demonstrated on math assessment data from a state, and a computationally…

  12. Capitalization on item calibration error in computer adaptive testing

    NARCIS (Netherlands)

    van der Linden, Willem J.; Glas, Cornelis A.W.

    2006-01-01

    In adaptive testing, item selection is sequentially optimized during the test. Since the optimization takes place over a pool of items calibrated with estimation error, capitalization on these errors is likely to occur. How serious the consequences of this phenomenon are depends not only on the

  13. Capitalization on item calibration error in adaptive testing

    NARCIS (Netherlands)

    van der Linden, Willem J.; Glas, Cornelis A.W.

    2000-01-01

    In adaptive testing, item selection is sequentially optimized during the test. Because the optimization takes place over a pool of items calibrated with estimation error, capitalization on chance is likely to occur.Howserious the consequences of this phenomenon are depends not only on the

  14. Capitalization on item calibration error in adaptive testing

    NARCIS (Netherlands)

    van der Linden, Willem J.; Glas, Cornelis A.W.

    1998-01-01

    In adaptive testing, item selection is sequentially optimized during the test. Since the optimization takes place over a pool of items calibrated with estimation error, capitalization on these errors is likely to occur. How serious the consequences of this phenomenon are depends not only on the

  15. Creating a Database for Test Items in National Examinations ...

    African Journals Online (AJOL)

    This paper looks at how to generate questions for national and local examinations without putting such questions (Items) at risk of leakage; reduce cost and time taken for such activities like time consuming items analysis and moderation; and improve on the poor selection which often characterized manually generated ...

  16. Comparing optimization algorithms for item selection in Mokken scale analysis

    NARCIS (Netherlands)

    Straat, J.H.; van der Ark, L.A.; Sijtsma, K.

    2013-01-01

    Mokken scale analysis uses an automated bottom-up stepwise item selection procedure that suffers from two problems. First, when selected during the procedure items satisfy the scaling conditions but they may fail to do so after the scale has been completed. Second, the procedure is approximate and

  17. Distinguishing between Net and Global DIF in Polytomous Items

    Science.gov (United States)

    Penfield, Randall D.

    2010-01-01

    In this article, I address two competing conceptions of differential item functioning (DIF) in polytomously scored items. The first conception, referred to as net DIF, concerns between-group differences in the conditional expected value of the polytomous response variable. The second conception, referred to as global DIF, concerns the conditional…

  18. Item response theory at subject- and group-level

    NARCIS (Netherlands)

    Tobi, Hilde

    1990-01-01

    This paper reviews the literature about item response models for the subject level and aggregated level (group level). Group-level item response models (IRMs) are used in the United States in large-scale assessment programs such as the National Assessment of Educational Progress and the California

  19. Is Approximate Number Precision a Stable Predictor of Math Ability?

    Science.gov (United States)

    Libertus, Melissa E.; Feigenson, Lisa; Halberda, Justin

    2013-01-01

    Previous research shows that children's ability to estimate numbers of items using their Approximate Number System (ANS) predicts later math ability. To more closely examine the predictive role of early ANS acuity on later abilities, we assessed the ANS acuity, math ability, and expressive vocabulary of preschoolers twice, six months apart. We…

  20. Mining multi-item drug adverse effect associations in spontaneous reporting systems

    Directory of Open Access Journals (Sweden)

    Chase Herbert S

    2010-10-01

    Full Text Available Abstract Background Multi-item adverse drug event (ADE associations are associations relating multiple drugs to possibly multiple adverse events. The current standard in pharmacovigilance is bivariate association analysis, where each single drug-adverse effect combination is studied separately. The importance and difficulty in the detection of multi-item ADE associations was noted in several prominent pharmacovigilance studies. In this paper we examine the application of a well established data mining method known as association rule mining, which we tailored to the above problem, and demonstrate its value. The method was applied to the FDAs spontaneous adverse event reporting system (AERS with minimal restrictions and expectations on its output, an experiment that has not been previously done on the scale and generality proposed in this work. Results Based on a set of 162,744 reports of suspected ADEs reported to AERS and published in the year 2008, our method identified 1167 multi-item ADE associations. A taxonomy that characterizes the associations was developed based on a representative sample. A significant number (67% of the total of potential multi-item ADE associations identified were characterized and clinically validated by a domain expert as previously recognized ADE associations. Several potentially novel ADEs were also identified. A smaller proportion (4% of associations were characterized and validated as known drug-drug interactions. Conclusions Our findings demonstrate that multi-item ADEs are present and can be extracted from the FDA’s adverse effect reporting system using our methodology, suggesting that our method is a valid approach for the initial identification of multi-item ADEs. The study also revealed several limitations and challenges that can be attributed to both the method and quality of data.

  1. Selection of relevant items for decommissioning costing estimation of a PWR using fuzzy logic

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro, Deiglys Borges; Busse, Alexander Lucas; Moreira, Joao M.L.; Maiorino, Jose Rubens, E-mail: deiglys.monteiro@ufabc.edu.br, E-mail: alexlucasb@gmail.com, E-mail: joao.moreira@ufabc.edu.br, E-mail: joserubens.maiorino@ufabc.edu.br [Universidade Federal do ABC (CECS/UFABC), Santo Andre, SP (Brazil). Centro de Engenharia, Modelagem e Ciencias Aplicadas. Programa de Pos-Graduacao em Energia e Engenharia da Energia

    2015-07-01

    The decommissioning is an important part of a nuclear power plant life cycle which may occur by technical, economical or safety reasons. Decommissioning requires carrying out a large number of tasks that should be planned in advance, involves cost evaluations, preparation of plans of activity and actual operational actions. Despite the large number of tasks, only part of them is relevant for cost estimation purpose. The technical literature and international regulatory agencies suggest a variety of methods for decommissioning cost estimation. Most of them require a very detailed knowledge of the plant and data available suitable for plants that are starting their decommissioning but not for those in the planning stage. The present work aims to apply fuzzy logic to sort out relevant items to cost estimation in order to reduce the work effort involved. The scheme uses parametric equations for specific cost items, and is applied to specific parts of the process of nuclear power plant decommissioning. (author)

  2. Geriatric Anxiety Scale: item response theory analysis, differential item functioning, and creation of a ten-item short form (GAS-10).

    Science.gov (United States)

    Mueller, Anne E; Segal, Daniel L; Gavett, Brandon; Marty, Meghan A; Yochim, Brian; June, Andrea; Coolidge, Frederick L

    2015-07-01

    The Geriatric Anxiety Scale (GAS; Segal et al. (Segal, D. L., June, A., Payne, M., Coolidge, F. L. and Yochim, B. (2010). Journal of Anxiety Disorders, 24, 709-714. doi:10.1016/j.janxdis.2010.05.002) is a self-report measure of anxiety that was designed to address unique issues associated with anxiety assessment in older adults. This study is the first to use item response theory (IRT) to examine the psychometric properties of a measure of anxiety in older adults. A large sample of older adults (n = 581; mean age = 72.32 years, SD = 7.64 years, range = 60 to 96 years; 64% women; 88% European American) completed the GAS. IRT properties were examined. The presence of differential item functioning (DIF) or measurement bias by age and sex was assessed, and a ten-item short form of the GAS (called the GAS-10) was created. All GAS items had discrimination parameters of 1.07 or greater. Items from the somatic subscale tended to have lower discrimination parameters than items on the cognitive or affective subscales. Two items were flagged for DIF, but the impact of the DIF was negligible. Women scored significantly higher than men on the GAS and its subscales. Participants in the young-old group (60 to 79 years old) scored significantly higher on the cognitive subscale than participants in the old-old group (80 years old and older). Results from the IRT analyses indicated that the GAS and GAS-10 have strong psychometric properties among older adults. We conclude by discussing implications and future research directions.

  3. The Lexicographic Treatment of Sublexical and Multilexical Items in a Northern Sotho Monolingual Dictionary: A Challenge for Lexicographers

    Directory of Open Access Journals (Sweden)

    Motlokwe Clifford Mphahlele

    2011-10-01

    Full Text Available

    Abstract: Dictionaries have in the past used a word-based approach in which sublexical and multilexical items were not regarded as lemmata. Metalexicography as the theoretical component of lexicography requires that sublexical and multilexical items be lemmatized and treated as independent lemmata in the macrostructure of dictionaries. One of the greater challenges for compiling a better and user-oriented Northern Sotho monolingual dictionary is to treat sublexical and multi-lexical items as macrostructural elements. Treating these items, the lexicographer faces quite a number of challenges. This article proposes possible ways in which sublexical and multilexical elements could be successfully treated in a Northern Sotho monolingual dictionary. Taking stock of these challenges, the writer comes with suggestions that would assist lexicographers in the compi-lation of a user-friendly, lexicon-based monolingual dictionary that would lead users to successful information retrieval.

    Keywords: SUBLEXICAL ITEMS, MULTILEXICAL ITEMS, AFFIXES, PREFIXAL MOR-PHEMES, SUFFIXAL MORPHEMES, INTEGRATED MICROSTRUCTURE, WORD-BASED APPROACH, LEMMATIZATION, COLLOCATIONS, COMPOUNDS, COMPLEXES, GROUP PREPOSITIONS, FIXED EXPRESSIONS, MORPHEMES, METALEXICOGRAPHICAL ASPECTS, WORD-FORMATION PROCESSES, WORD-INTERNAL FUNCTION, USER-ORIENTED MONO-LINGUAL DICTIONARY, GRAMMAR, HOMONYMOUS LEMMA, POLYSEMOUS LEMMA, DECODING, ENCODING, SEMANTIC COMMENT, SEMANTIC TRANSPARENCY

    Opsomming: Die leksikografiese behandeling van subleksikale en multi-leksikale items in 'n Noord-Sotho- eentalige woordeboek: 'n Uitdaging vir leksikograwe. Woordeboeke het in die verlede 'n woordgebaseerde benadering gevolg waar-by subleksikale en multileksikale items nie as lemmas beskou is nie. Die metaleksikografie as die teoretiese komponent van die leksikografie vereis dat subleksikale en multileksikale items gelem-matiseer word en as onafhanklike lemmas in die makrostuktuur van woordeboeke

  4. 41 CFR 101-26.605 - Items other than petroleum products and electronic items available from the Defense Logistics...

    Science.gov (United States)

    2010-07-01

    ... petroleum products and electronic items available from the Defense Logistics Agency. 101-26.605 Section 101... available from the Defense Logistics Agency. Agencies required to use GSA supply sources should also use... Logistics Agency, the catalog will contain only those items in Federal supply classification classes which...

  5. The use of predicted values for item parameters in item response theory models: An application in intelligence tests

    NARCIS (Netherlands)

    Matteucci, M.; S. Mignani, Prof.; Veldkamp, Bernard P.

    2012-01-01

    In testing, item response theory models are widely used in order to estimate item parameters and individual abilities. However, even unidimensional models require a considerable sample size so that all parameters can be estimated precisely. The introduction of empirical prior information about

  6. Generalizability and Dependability of Single-Item and Multiple-Item Direct Behavior Rating Scales for Engagement and Disruptive Behavior

    Science.gov (United States)

    Volpe, Robert J.; Briesch, Amy M.

    2012-01-01

    Direct behavior rating (DBR) has been described as a hybrid of systematic direct observation and behavior rating scales. Although single-item (DBR-SIS) and multi-item (DBR-MIS) methods have been advocated, the overwhelming majority of research attention has focused on DBR-SIS. This study employed generalizability theory to compare the…

  7. Exploring the Relevance of Items in the Communicative Participation Item Bank (CPIB) for Individuals With Hearing Loss

    Science.gov (United States)

    Baylor, Carolyn R.; Birch, Kristen; Yorkston, Kathryn M.

    2017-01-01

    Purpose The Communicative Participation Item Bank (CPIB) was developed to evaluate participation restrictions in communication situations for individuals with speech and language disorders. This study evaluated the potential relevance of CPIB items for individuals with hearing loss. Method Cognitive interviews were conducted with 17 adults with a range of treated and untreated hearing loss, who responded to 46 items. Interviews were continued until saturation was reached and prevalent trends emerged. A focus group was also conducted with 3 experienced audiologists to seek their views on the CPIB. Analysis of data included qualitative and quantitative approaches. Results The majority of the items were applicable to individuals with hearing loss; however, 12 items were identified as potentially not relevant. This was largely attributed to the items' focus on speech production rather than hearing. The results from the focus group were in agreement for a majority of items. Conclusions The next step in validating the CPIB for individuals with hearing loss is a psychometric analysis on a large sample. Possible outcomes could be that the CPIB is considered valid in its entirety or the creation of a new questionnaire or a hearing loss–specific short form with a subset of items is necessary. PMID:28114665

  8. The Academic Medical Center Linear Disability Score (ALDS) item bank: item response theory analysis in a mixed patient population

    NARCIS (Netherlands)

    Holman, Rebecca; Weisscher, Nadine; Glas, Cees A. W.; Dijkgraaf, Marcel G. W.; Vermeulen, Marinus; de Haan, Rob J.; Lindeboom, Robert

    2005-01-01

    BACKGROUND: Currently, there is a lot of interest in the flexible framework offered by item banks for measuring patient relevant outcomes. However, there are few item banks, which have been developed to quantify functional status, as expressed by the ability to perform activities of daily life. This

  9. The academic medical center linear disability score (ALDS) item bank: item response theory analysis in a mixed patient population

    NARCIS (Netherlands)

    Holman, Rebecca; Weisscher, Nadine; Glas, Cornelis A.W.; Dijkgraaf, Marcel G.W.; Vermeulen, Martinus; de Haan, Rob J.; Lindeboom, Robert

    2005-01-01

    Background: Currently, there is a lot of interest in the flexible framework offered by item banks for measuring patient relevant outcomes. However, there are few item banks, which have been developed to quantify functional status, as expressed by the ability to perform activities of daily life. This

  10. Do images influence assessment in anatomy? Exploring the effect of images on item difficulty and item discrimination.

    NARCIS (Netherlands)

    Vorstenbosch, M.A.T.M.; Klaassen, T.P.; Kooloos, J.G.M.; Bolhuis, S.M.; Laan, R.F.J.M.

    2013-01-01

    Anatomists often use images in assessments and examinations. This study aims to investigate the influence of different types of images on item difficulty and item discrimination in written assessments. A total of 210 of 460 students volunteered for an extra assessment in a gross anatomy course. This

  11. Creation of New Items and Forms for the Project A Assembling Objects Test

    Science.gov (United States)

    1994-08-01

    correct; D, a measure of item discrimination - the rpbi , between the item score (correct or incorrect) and the total score on the 36 original items...D2 another measure of item discrimination - the rpbis between the item score and the total score on the 18 original items of the same type (marked

  12. Remembered but Unused: The Accessory Items in Working Memory that Do Not Guide Attention

    Science.gov (United States)

    Peters, Judith C.; Goebel, Rainer; Roelfsema, Pieter R.

    2009-01-01

    If we search for an item, a representation of this item in our working memory guides attention to matching items in the visual scene. We can hold multiple items in working memory. Do all these items guide attention in parallel? We asked participants to detect a target object in a stream of objects while they maintained a second item in memory for…

  13. Item Purification Does Not Always Improve DIF Detection: A Counterexample with Angoff's Delta Plot

    Science.gov (United States)

    Magis, David; Facon, Bruno

    2013-01-01

    Item purification is an iterative process that is often advocated as improving the identification of items affected by differential item functioning (DIF). With test-score-based DIF detection methods, item purification iteratively removes the items currently flagged as DIF from the test scores to get purified sets of items, unaffected by DIF. The…

  14. The quadratic relationship between difficulty of intelligence test items and their correlations with working memory

    OpenAIRE

    Smolen, Tomasz; Chuderski, Adam

    2015-01-01

    Fluid intelligence (Gf) is a crucial cognitive ability that involves abstract reasoning in order to solve novel problems. Recent research demonstrated that Gf strongly depends on the individual effectiveness of working memory (WM). We investigated a popular claim that if the storage capacity underlay the WM-Gf correlation, then such a correlation should increase with an increasing number of items or rules (load) in a Gf test. As often no such link is observed, on that basis the storage-capaci...

  15. Development of a Parent-Report Cognitive Function Item Bank Using Item Response Theory and Exploration of its Clinical Utility in Computerized Adaptive Testing

    National Research Council Canada - National Science Library

    Lai, Jin-Shei; Butt, Zeeshan; Zelko, Frank; Cella, David; Krull, Kevin R; Kieran, Mark W; Goldman, Stewart

    2011-01-01

    .... A computerized adaptive testing (CAT) simulation was used to evaluate clinical utility. Results The final 43-item pedsPCF item bank demonstrates no item bias, has acceptable IRT parameters, and provides good prediction of related clinical problems...

  16. Introduction to number theory

    CERN Document Server

    Vazzana, Anthony; Garth, David

    2007-01-01

    One of the oldest branches of mathematics, number theory is a vast field devoted to studying the properties of whole numbers. Offering a flexible format for a one- or two-semester course, Introduction to Number Theory uses worked examples, numerous exercises, and two popular software packages to describe a diverse array of number theory topics.

  17. Tropical Real Hurwitz numbers

    OpenAIRE

    Markwig, Hannah; Rau, Johannes

    2014-01-01

    In this paper, we define tropical analogues of real Hurwitz numbers, i.e. numbers of covers of surfaces with compatible involutions satisfying prescribed ramification properties. We prove a correspondence theorem stating the equality of the tropical numbers with their real counterparts. We apply this theorem to the case of double Hurwitz numbers (which generalizes our result from arXiv:1409.8095).

  18. Psychometric properties of the Arabic version of the 12-item diabetes fatalism scale.

    Directory of Open Access Journals (Sweden)

    Ola Sukkarieh-Haraty

    Full Text Available There are widespread fatalistic beliefs in Arab countries, especially among individuals with diabetes. However, there is no tool to assess diabetes fatalism in this population. This study describes the processes used to create an Arabic version of the Diabetes Fatalism Scale (DFS and examine its psychometric properties.A descriptive correlational design was used with a convenience sample of Lebanese adults (N = 274 with type 2 diabetes recruited from a major hospital in Beirut, Lebanon and by snowball sampling. The 12- item Diabetes Fatalism Scale- Arabic (12-item DFS-Ar was back-translated from the original version, pilot tested on 22 adults with type 2 diabetes and then administered to 274 patients to assess the validity and reliability of the scale. Confirmatory factor analysis (CFA was used to test the hypothesized factor structure. Cronbach's alpha was used to test for reliability.CFA supported the existence of the three factor hypothesis of the original DFS scale. The five items measuring "emotional distress" loaded under Factor 1, the four items measuring "spiritual coping" loaded under factor 2 and the last three items measuring "perceived self-efficacy" of the original scale loaded under Factor 3 (p <0.001 for all three subscales. Goodness of fit indices confirmed adequateness of the CFA model (CFI = 0.97, TLI = 0.96, RMSEA = 0.067 and pclose = 0.05. The 12-item DFS-Ar showed good reliability (Cronbach's alpha of 0.86 and significantly predicted HbA1c (β = 0.20, p < 0.01. After adjusting for the demographic characteristics and the number of diabetes comorbid conditions, the 12-item DFS-Ar score was independently associated with HbA1c in a multivariable model (β = 0.16, p < 0.05.The 12-item DFS-Ar demonstrated good psychometric properties that are comparable to the original scale. It is a valid and reliable measure of diabetes fatalism. Further testing with larger and non-Lebanese Arabic population is needed.

  19. Group differences in the heritability of items and test scores

    Science.gov (United States)

    Wicherts, Jelte M.; Johnson, Wendy

    2009-01-01

    It is important to understand potential sources of group differences in the heritability of intelligence test scores. On the basis of a basic item response model we argue that heritabilities which are based on dichotomous item scores normally do not generalize from one sample to the next. If groups differ in mean ability, the functioning of items at different ability levels may result in group differences in the heritability of items, even when these items function equivalently across groups and the heritability of the underlying ability is equal across groups. We illustrate this graphically, by computer simulation, and by focusing on several problems associated with a recent study by Rushton et al. who argued that the heritability estimates of items of Raven's Progressive Matrices test in North-American twin samples generalized to other population groups, and hence that the population group differences on this test of general mental ability (or intelligence) had a substantial genetic component. Our results show that item heritabilities are strongly dependent on the group on which the heritabilities were based. Rushton et al.'s results were artefactual and do not speak to the nature of population group differences in intelligence test performance. PMID:19403538

  20. Graphical modeling for item difficulty in medical faculty exams.

    Science.gov (United States)

    Tomak, L; Bek, Y; Cengiz, M A

    2016-01-01

    There are different indexes used in the evaluation of exam results. One important index is the difficulty level of the item that is also used in this study to obtain control charts. This article offers some suggestions for the improvement of multiple-choice tests using item analysis statistics. The graphical modeling is important for the rapid and comparative evaluation of test results. The control chart is a tool that can be used to sharpen our teaching and testing skills by inspecting the weaknesses of measurements and producing reliable items. The research data for the application of control charts were obtained using the results of the fourth and fifth-grade student's exams at Ondokuz Mayis University, Faculty of Medicine. I-chart or moving range chart (MR) is preferred for whole variable data. It is seen that all observations are within control limits for I-chart, but three points on MR-chart are settled on the LCL. Using X--chart with subgroups, it was determined that control measurements were within the upper and lower limits in both charts. The difficulty levels of items were examined by obtaining different variable control charts. The difficulty level of the two items exceeded the upper control limit in R- and S-charts. The control charts have the advantage for classifying items as acceptable or unacceptable based on item difficulty criteria.

  1. LLWnotes - Volume 11, Number 3

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-04-01

    This document is the April 1996 issue of LLWnotes. It contains articles and news items on the following topics: news items related to states and compacts, Low-Level Radioactive Waste (LLW) Forum activities, and court rulings and calendars. State and compact items featured include Texas licensing procedures, renewal of Envirocare`s license, and Ward Valley. Massachusetts Board suspension of some siting tasks and Massachusetts Court rules for US DOE regarding rebates are also reported.

  2. Science Literacy: How do High School Students Solve PISA Test Items?

    Science.gov (United States)

    Wati, F.; Sinaga, P.; Priyandoko, D.

    2017-09-01

    The Programme for International Students Assessment (PISA) does assess students’ science literacy in a real-life contexts and wide variety of situation. Therefore, the results do not provide adequate information for the teacher to excavate students’ science literacy because the range of materials taught at schools depends on the curriculum used. This study aims to investigate the way how junior high school students in Indonesia solve PISA test items. Data was collected by using PISA test items in greenhouse unit employed to 36 students of 9th grade. Students’ answer was analyzed qualitatively for each item based on competence tested in the problem. The way how students answer the problem exhibits their ability in particular competence which is influenced by a number of factors. Those are students’ unfamiliarity with test construction, low performance on reading, low in connecting available information and question, and limitation on expressing their ideas effectively and easy-read. As the effort, selected PISA test items can be used in accordance teaching topic taught to familiarize students with science literacy.

  3. Comparing children's Homo sapiens and chimpanzees' Pan troglodytes quantity judgments of sequentially presented sets of items

    Directory of Open Access Journals (Sweden)

    Michael J. BERAN, Julie S. JOHNSON-PYNN, Christopher READY

    2011-08-01

    Full Text Available We presented a quantity judgment task that involved comparing two sequentially presented sets of items to preschoolers and chimpanzees using nearly identical procedures that excluded verbal instructions to children. Trial difficulty in this task reflected the ratio difference between sets of discrete items where larger ratios (e.g., 0.80 as from comparing 4 to 5 were more difficult than smaller ones (e.g., 0.50 as from comparing 4 to 8. Children also completed verbal-based tasks probing the relationship between counting proficiency and performance on the quantity judgment task of sequentially presented identical sized items. Both species’ performance was best when ratios between comparison sets were small regardless of set size in all types of tasks. Generally, chimpanzees and older children performed better than younger children except at larger ratios. Children’s counting proficiency was not related to success in choosing the larger of two quantities of identical-sized items. These results indicate that chimpanzees and children share an approximate number sense that is reflected through analog magnitude estimation when comparing quantities [Current Zoology 57 (4: 419–428, 2011].

  4. Faculty development programs improve the quality of Multiple Choice Questions items' writing.

    Science.gov (United States)

    Abdulghani, Hamza Mohammad; Ahmad, Farah; Irshad, Mohammad; Khalil, Mahmoud Salah; Al-Shaikh, Ghadeer Khalid; Syed, Sadiqa; Aldrees, Abdulmajeed Abdurrahman; Alrowais, Norah; Haque, Shafiul

    2015-04-01

    The aim of this study was to assess the utility of long term faculty development programs (FDPs) in order to improve the quality of multiple choice questions (MCQs) items' writing. This was a quasi-experimental study, conducted with newly joined faculty members. The MCQ items were analyzed for difficulty index, discriminating index, reliability, Bloom's cognitive levels, item writing flaws (IWFs) and MCQs' nonfunctioning distractors (NFDs) based test courses of respiratory, cardiovascular and renal blocks. Significant improvement was found in the difficulty index values of pre- to post-training (p = 0.003). MCQs with moderate difficulty and higher discrimination were found to be more in the post-training tests in all three courses. Easy questions were decreased from 36.7 to 22.5%. Significant improvement was also reported in the discriminating indices from 92.1 to 95.4% after training (p = 0.132). More number of higher cognitive level of Bloom's taxonomy was reported in the post-training test items (pwriting.

  5. A simulation study provided sample size guidance for differential item functioning (DIF) studies using short scales.

    Science.gov (United States)

    Scott, Neil W; Fayers, Peter M; Aaronson, Neil K; Bottomley, Andrew; de Graeff, Alexander; Groenvold, Mogens; Gundy, Chad; Koller, Michael; Petersen, Morten A; Sprangers, Mirjam A G

    2009-03-01

    Differential item functioning (DIF) analyses are increasingly used to evaluate health-related quality of life (HRQoL) instruments, which often include relatively short subscales. Computer simulations were used to explore how various factors including scale length affect analysis of DIF by ordinal logistic regression. Simulated data, representative of HRQoL scales with four-category items, were generated. The power and type I error rates of the DIF method were then investigated when, respectively, DIF was deliberately introduced and when no DIF was added. The sample size, scale length, floor effects (FEs) and significance level were varied. When there was no DIF, type I error rates were close to 5%. Detecting moderate uniform DIF in a two-item scale required a sample size of 300 per group for adequate (>80%) power. For longer scales, a sample size of 200 was adequate. Considerably larger sample sizes were required to detect nonuniform DIF, when there were extreme FEs or when a reduced type I error rate was required. The impact of the number of items in the scale was relatively small. Ordinal logistic regression successfully detects DIF for HRQoL instruments with short scales. Sample size guidelines are provided.

  6. Lexicalizing number and gender in Lunigiana

    Directory of Open Access Journals (Sweden)

    Knut Tarald Taraldsen

    2009-01-01

    Full Text Available In this article, I present an analysis of gender and number marking on nouns in a group of Italian dialects. These dialects share the property that the plural morpheme is -i- in both the feminine and the masculine gender in both declension classes. But there is an asymmetry: in contexts where plurality is marked on a determiner, the plural marking -i- does not appear on nouns or adjectives in the feminine gender, but does appear on masculine nouns and adjectives. I argue that this asymmetry can be understood once it is recognized that a vocabulary item can lexicalize more than a single terminal, and that lexicalization is governed by the Superset Principle, i.e. if the lexicon associates a vocabulary item with a feature set F, it can lexicalize any constituent with the feature set F' provided F is a superset of F'.

  7. Identifying predictors of physics item difficulty: A linear regression approach

    Science.gov (United States)

    Mesic, Vanes; Muratovic, Hasnija

    2011-06-01

    Large-scale assessments of student achievement in physics are often approached with an intention to discriminate students based on the attained level of their physics competencies. Therefore, for purposes of test design, it is important that items display an acceptable discriminatory behavior. To that end, it is recommended to avoid extraordinary difficult and very easy items. Knowing the factors that influence physics item difficulty makes it possible to model the item difficulty even before the first pilot study is conducted. Thus, by identifying predictors of physics item difficulty, we can improve the test-design process. Furthermore, we get additional qualitative feedback regarding the basic aspects of student cognitive achievement in physics that are directly responsible for the obtained, quantitative test results. In this study, we conducted a secondary analysis of data that came from two large-scale assessments of student physics achievement at the end of compulsory education in Bosnia and Herzegovina. Foremost, we explored the concept of “physics competence” and performed a content analysis of 123 physics items that were included within the above-mentioned assessments. Thereafter, an item database was created. Items were described by variables which reflect some basic cognitive aspects of physics competence. For each of the assessments, Rasch item difficulties were calculated in separate analyses. In order to make the item difficulties from different assessments comparable, a virtual test equating procedure had to be implemented. Finally, a regression model of physics item difficulty was created. It has been shown that 61.2% of item difficulty variance can be explained by factors which reflect the automaticity, complexity, and modality of the knowledge structure that is relevant for generating the most probable correct solution, as well as by the divergence of required thinking and interference effects between intuitive and formal physics knowledge

  8. Line-item Budgeting and Film-Production

    DEFF Research Database (Denmark)

    Friis, Ivar; Hansen, Allan

    2015-01-01

    conducted a case study on the making of a Danish adventure film and analysed the role budgeting plays from the film director’s point of view. Findings – This paper suggests that the constraints of the line-item budget imposed on the director had positive effects in terms of the pre-commitments entailed...... of line-item budgeting, adding greater insight into the interrelations between creativity and control. By exploring the ways in which line-item budgeting might take on the role of pre-commitment advice and devices in the creative process, this paper further exposes the links between accounting constraints...

  9. Identifying predictors of physics item difficulty: A linear regression approach

    Directory of Open Access Journals (Sweden)

    Vanes Mesic

    2011-06-01

    Full Text Available Large-scale assessments of student achievement in physics are often approached with an intention to discriminate students based on the attained level of their physics competencies. Therefore, for purposes of test design, it is important that items display an acceptable discriminatory behavior. To that end, it is recommended to avoid extraordinary difficult and very easy items. Knowing the factors that influence physics item difficulty makes it possible to model the item difficulty even before the first pilot study is conducted. Thus, by identifying predictors of physics item difficulty, we can improve the test-design process. Furthermore, we get additional qualitative feedback regarding the basic aspects of student cognitive achievement in physics that are directly responsible for the obtained, quantitative test results. In this study, we conducted a secondary analysis of data that came from two large-scale assessments of student physics achievement at the end of compulsory education in Bosnia and Herzegovina. Foremost, we explored the concept of “physics competence” and performed a content analysis of 123 physics items that were included within the above-mentioned assessments. Thereafter, an item database was created. Items were described by variables which reflect some basic cognitive aspects of physics competence. For each of the assessments, Rasch item difficulties were calculated in separate analyses. In order to make the item difficulties from different assessments comparable, a virtual test equating procedure had to be implemented. Finally, a regression model of physics item difficulty was created. It has been shown that 61.2% of item difficulty variance can be explained by factors which reflect the automaticity, complexity, and modality of the knowledge structure that is relevant for generating the most probable correct solution, as well as by the divergence of required thinking and interference effects between intuitive and formal

  10. P2-19: The Effect of item Repetition on Item-Context Association Depends on the Prior Exposure of Items

    Directory of Open Access Journals (Sweden)

    Hongmi Lee

    2012-10-01

    Full Text Available Previous studies have reported conflicting findings on whether item repetition has beneficial or detrimental effects on source memory. To reconcile such contradictions, we investigated whether the degree of pre-exposure of items can be a potential modulating factor. The experimental procedures spanned two consecutive days. On Day 1, participants were exposed to a set of unfamiliar faces. On Day 2, the same faces presented on the previous day were used again in half of the participants, whereas novel faces were used for the other half. Day 2 procedures consisted of three successive phases: item repetition, source association, and source memory test. In the item repetition phase, half of the face stimuli were repeatedly presented while participants were making male/female judgments. During the source association phase, both the repeated and the unrepeated faces appeared in one of the four locations on the screen. Finally, participants were tested on the location in which a given face was presented during the previous phase and reported the confidence of their memory. Source memory accuracy was measured as the percentage of correct non-guess trials. As results, we found a significant interaction between prior exposure and repetition. Repetition impaired source memory when the items had been pre-exposed on Day 1, while it led to greater accuracy in novel ones. These results show that pre-experimental exposure can modulate the effects of repetition on associative binding between an item and its contextual information, suggesting that pre-existing representation and novelty signal interact to form new episodic memory.

  11. Algebraic number theory

    CERN Document Server

    Jarvis, Frazer

    2014-01-01

    The technical difficulties of algebraic number theory often make this subject appear difficult to beginners. This undergraduate textbook provides a welcome solution to these problems as it provides an approachable and thorough introduction to the topic. Algebraic Number Theory takes the reader from unique factorisation in the integers through to the modern-day number field sieve. The first few chapters consider the importance of arithmetic in fields larger than the rational numbers. Whilst some results generalise well, the unique factorisation of the integers in these more general number fields often fail. Algebraic number theory aims to overcome this problem. Most examples are taken from quadratic fields, for which calculations are easy to perform. The middle section considers more general theory and results for number fields, and the book concludes with some topics which are more likely to be suitable for advanced students, namely, the analytic class number formula and the number field sieve. This is the fi...

  12. Why item parcels are (almost) never appropriate: two wrongs do not make a right--camouflaging misspecification with item parcels in CFA models.

    Science.gov (United States)

    Marsh, Herbert W; Lüdtke, Oliver; Nagengast, Benjamin; Morin, Alexandre J S; Von Davier, Matthias

    2013-09-01

    The present investigation has a dual focus: to evaluate problematic practice in the use of item parcels and to suggest exploratory structural equation models (ESEMs) as a viable alternative to the traditional independent clusters confirmatory factor analysis (ICM-CFA) model (with no cross-loadings, subsidiary factors, or correlated uniquenesses). Typically, it is ill-advised to (a) use item parcels when ICM-CFA models do not fit the data, and (b) retain ICM-CFA models when items cross-load on multiple factors. However, the combined use of (a) and (b) is widespread and often provides such misleadingly good fit indexes that applied researchers might believe that misspecification problems are resolved--that 2 wrongs really do make a right. Taking a pragmatist perspective, in 4 studies we demonstrate with responses to the Rosenberg Self-Esteem Inventory (Rosenberg, 1965), Big Five personality factors, and simulated data that even small cross-loadings seriously distort relations among ICM-CFA constructs or even decisions on the number of factors; although obvious in item-level analyses, this is camouflaged by the use of parcels. ESEMs provide a viable alternative to ICM-CFAs and a test for the appropriateness of parcels. The use of parcels with an ICM-CFA model is most justifiable when the fit of both ICM-CFA and ESEM models is acceptable and equally good, and when substantively important interpretations are similar. However, if the ESEM model fits the data better than the ICM-CFA model, then the use of parcels with an ICM-CFA model typically is ill-advised--particularly in studies that are also interested in scale development, latent means, and measurement invariance.

  13. p-adic numbers

    OpenAIRE

    Grešak, Rozalija

    2015-01-01

    The field of real numbers is usually constructed using Dedekind cuts. In these thesis we focus on the construction of the field of real numbers using metric completion of rational numbers using Cauchy sequences. In a similar manner we construct the field of p-adic numbers, describe some of their basic and topological properties. We follow by a construction of complex p-adic numbers and we compare them with the ordinary complex numbers. We conclude the thesis by giving a motivation for the int...

  14. Safety-in-numbers

    DEFF Research Database (Denmark)

    Elvik, Rune; Bjørnskau, Torkel

    2017-01-01

    Highlights •26 studies of the safety-in-numbers effect are reviewed. •The existence of a safety-in-numbers effect is confirmed. •Results are consistent. •Causes of the safety-in-numbers effect are incompletely known.......Highlights •26 studies of the safety-in-numbers effect are reviewed. •The existence of a safety-in-numbers effect is confirmed. •Results are consistent. •Causes of the safety-in-numbers effect are incompletely known....

  15. Differential item functioning (DIF) of SF-12 and Q-LES-Q-SF items among french substance users.

    Science.gov (United States)

    Bourion-Bédès, Stéphanie; Schwan, Raymund; Laprevote, Vincent; Bédès, Alex; Bonnet, Jean-Louis; Baumann, Cédric

    2015-10-24

    Differential Item Functioning (DIF) is investigated to ensure that each item displays a consistent pattern of responses irrespective of the characteristics of the respondents. Assessing DIF helps to understand the nature of instruments, to assess the quality of a measure and to interpret results. This study aimed to examine whether the items of the Quality of Life Enjoyment and Satisfaction Questionnaire-Short Form (Q-LES-Q-SF) and Short-Form 12 (SF-12) exhibit DIF. A total of 124 outpatients diagnosed with substance dependence participated in a cross-sectional, multicenter study. In addition to the Q-LES-Q-SF and SF-12 results, demographic data such as age, sex, type of substance dependence and education level were collected. Rasch analysis was conducted (using RUMM2020 software) to assess DIF of the Q-LES-Q-SF and SF-12 items. For SF-12, significant age-related uniform DIF was found in two of the 12 items, and sex-related DIF was found in one of the 12 items. All of the observed DIF effects in SF-12 were found among the mental health items. Three items showed DIF on the Q-LES-Q-SF; however, the impact of DIF item on the delta score calculation for the comparisons of self-reported health status between the groups was minimal in the SF-12 and small in the Q-LES-Q-SF. These results indicated that no major measurement bias affects the validity of the self-reported health status assessed using the Q-LES-Q-SF or SF-12. Thus, these questionnaires are largely robust measures of self-reported health status among substance users.

  16. Separation index and fit items of creative thinking skills assessment

    Directory of Open Access Journals (Sweden)

    Andi Ulfa Tenri Pada

    2016-06-01

    Full Text Available This article discusses the evaluation results of the separation index and fit item of creative thinking skills assessment that supports the conation aspect of prospective biology teachers in Aceh. This assessment consists of 37 items of divergent tasks, which is the application of human physiology courses that support the conation aspects. The participants were selected from the Biology Education Program, Faculty of Teacher Training and Education, Syiah Kuala University. The data were analyzed using the Quest software including the separation index and fit item. The results indicate that the creative thinking skills assessment instrument that supports the conation aspect of prospective biology teachers has a good separation index and all the items fit PCM-1PL.

  17. Can the Focus of Attention Accommodate Multiple, Separate Items?

    Science.gov (United States)

    Gilchrist, Amanda L.; Cowan, Nelson

    2011-01-01

    Researchers of working memory currently debate capacity limits of the focus of attention, the proposed mental faculty in which items are most easily accessed. Cowan (1999) suggested that its capacity is about 4 chunks, whereas others have suggested that its capacity is only 1 chunk. Recently, Oberauer and Bialkova (2009) found evidence that 2 items could reside in the focus of attention, but only because they were combined into a single chunk. We modified their experimental procedure, which depends on a pattern of switch costs, to obtain a situation in which chunking was not likely to occur (i.e., each item remained a separate chunk), and still obtained results consistent with a capacity of at least 2 items. Therefore, either the focus of attention can hold multiple chunks, or the switch cost logic must be reconsidered. PMID:21767065

  18. Etendatakse 10-aastase kirjamehe näitemäng

    Index Scriptorium Estoniae

    2003-01-01

    Tartu katoliku kooli 3. klassi poisi Mario Raitari näitemäng "Kristoph Silvester von Tenderi lugu", mis on esimene lugu sarjast "Mario Raitari kroonika". Näidendit etendab Linnupuu Lastepereteatri trupp

  19. 75 FR 6795 - Designation of Biobased Items for Federal Procurement

    Science.gov (United States)

    2010-02-10

    ... procurement preference: Disposable tableware; expanded polystyrene foam recycling products; heat transfer... following items for preferred procurement: Disposable tableware; expanded polystyrene (EPS) foam recycling... (``expandable polystyrene foam recycling products'') is based on a single tested product. Given that only two...

  20. Modular Open-Source Software for Item Factor Analysis.

    Science.gov (United States)

    Pritikin, Joshua N; Hunter, Micheal D; Boker, Steven

    2015-06-01

    This paper introduces an Item Factor Analysis (IFA) module for OpenMx, a free, open-source, and modular statistical modeling package that runs within the R programming environment on GNU/Linux, Mac OS X, and Microsoft Windows. The IFA module offers a novel model specification language that is well suited to programmatic generation and manipulation of models. Modular organization of the source code facilitates the easy addition of item models, item parameter estimation algorithms, optimizers, test scoring algorithms, and fit diagnostics all within an integrated framework. Three short example scripts are presented for fitting item parameters, latent distribution parameters, and a multiple group model. The availability of both IFA and structural equation modeling in the same software is a step toward the unification of these two methodologies.

  1. Bayesian longitudinal item response modeling with restricted covariance pattern structures

    NARCIS (Netherlands)

    Azevedo, Caio L.N.; Fox, Gerardus J.A.; Andrade, Dalton F.

    2016-01-01

    Educational studies are often focused on growth in student performance and background variables that can explain developmental differences across examinees. To study educational progress, a flexible latent variable model is required to model individual differences in growth given longitudinal item

  2. 17 CFR 229.1111 - (Item 1111) Pool assets.

    Science.gov (United States)

    2010-04-01

    ... AND CONSERVATION ACT OF 1975-REGULATION S-K Asset-Backed Securities (Regulation AB) § 229.1111 (Item.... (vi) Finance charges, fees and other income earned. (vii) Balance reductions granted for refunds...

  3. On the number of special numbers

    Indian Academy of Sciences (India)

    We now apply the theory of the Thue equation to obtain an effective bound on m. Indeed, by Lemma 3.2, we can write m2 = ba3 and m2 − 4 = cd3 with b, c cubefree. By the above, both b, c are bounded since they are cubefree and all their prime factors are less than e63727. Now we have a finite number of. Thue equations:.

  4. Calibration of the Spanish PROMIS Smoking Item Banks

    Science.gov (United States)

    Stucky, Brian D.; Edelen, Maria O.; Tucker, Joan S.; Shadel, William G.; Hansen, Mark; Cai, Li

    2016-01-01

    Introduction: The Patient-Reported Outcomes Measurement Information System (PROMIS) Smoking Initiative has developed item banks for assessing six smoking behaviors and biopsychosocial correlates of smoking among adult cigarette smokers. The goal of this study is to evaluate the performance of the Spanish version of the PROMIS smoking item banks as compared to the original banks developed in English. Methods: The six PROMIS banks for daily smokers were translated into Spanish and administered to a sample of Spanish-speaking adult daily smokers in the United States (N = 302). We first evaluated the unidimensionality of each bank using confirmatory factor analysis. We then conducted a two-group item response theory calibration, including an item response theory-based Differential Item Functioning (DIF) analysis by language of administration (Spanish vs. English). Finally, we generated full bank and short form scores for the translated banks and evaluated their psychometric performance. Results: Unidimensionality of the Spanish smoking item banks was supported by confirmatory factor analysis results. Out of a total of 109 items that were evaluated for language DIF, seven items in three of the six banks were identified as having levels of DIF that exceeded an established criterion. The psychometric performance of the Spanish daily smoker banks is largely comparable to that of the English versions. Conclusions: The Spanish PROMIS smoking item banks are highly similar, but not entirely equivalent, to the original English versions. The parameters from these two-group calibrations can be used to generate comparable bank scores across the two language versions. Implications: In this study, we developed a Spanish version of the PROMIS smoking toolkit, which was originally designed and developed for English speakers. With the growing Spanish-speaking population, it is important to make the toolkit more accessible by translating the items and calibrating the Spanish version to

  5. Development of six PROMIS pediatrics proxy-report item banks

    Directory of Open Access Journals (Sweden)

    Irwin Debra E

    2012-02-01

    Full Text Available Abstract Background Pediatric self-report should be considered the standard for measuring patient reported outcomes (PRO among children. However, circumstances exist when the child is too young, cognitively impaired, or too ill to complete a PRO instrument and a proxy-report is needed. This paper describes the development process including the proxy cognitive interviews and large-field-test survey methods and sample characteristics employed to produce item parameters for the Patient Reported Outcomes Measurement Information System (PROMIS pediatric proxy-report item banks. Methods The PROMIS pediatric self-report items were converted into proxy-report items before undergoing cognitive interviews. These items covered six domains (physical function, emotional distress, social peer relationships, fatigue, pain interference, and asthma impact. Caregivers (n = 25 of children ages of 5 and 17 years provided qualitative feedback on proxy-report items to assess any major issues with these items. From May 2008 to March 2009, the large-scale survey enrolled children ages 8-17 years to complete the self-report version and caregivers to complete the proxy-report version of the survey (n = 1548 dyads. Caregivers of children ages 5 to 7 years completed the proxy report survey (n = 432. In addition, caregivers completed other proxy instruments, PedsQL™ 4.0 Generic Core Scales Parent Proxy-Report version, PedsQL™ Asthma Module Parent Proxy-Report version, and KIDSCREEN Parent-Proxy-52. Results Item content was well understood by proxies and did not require item revisions but some proxies clearly noted that determining an answer on behalf of their child was difficult for some items. Dyads and caregivers of children ages 5-17 years old were enrolled in the large-scale testing. The majority were female (85%, married (70%, Caucasian (64% and had at least a high school education (94%. Approximately 50% had children with a chronic health condition, primarily

  6. Calibration of the Spanish PROMIS Smoking Item Banks.

    Science.gov (United States)

    Huang, Wenjing; Stucky, Brian D; Edelen, Maria O; Tucker, Joan S; Shadel, William G; Hansen, Mark; Cai, Li

    2016-07-01

    The Patient-Reported Outcomes Measurement Information System (PROMIS) Smoking Initiative has developed item banks for assessing six smoking behaviors and biopsychosocial correlates of smoking among adult cigarette smokers. The goal of this study is to evaluate the performance of the Spanish version of the PROMIS smoking item banks as compared to the original banks developed in English. The six PROMIS banks for daily smokers were translated into Spanish and administered to a sample of Spanish-speaking adult daily smokers in the United States (N = 302). We first evaluated the unidimensionality of each bank using confirmatory factor analysis. We then conducted a two-group item response theory calibration, including an item response theory-based Differential Item Functioning (DIF) analysis by language of administration (Spanish vs. English). Finally, we generated full bank and short form scores for the translated banks and evaluated their psychometric performance. Unidimensionality of the Spanish smoking item banks was supported by confirmatory factor analysis results. Out of a total of 109 items that were evaluated for language DIF, seven items in three of the six banks were identified as having levels of DIF that exceeded an established criterion. The psychometric performance of the Spanish daily smoker banks is largely comparable to that of the English versions. The Spanish PROMIS smoking item banks are highly similar, but not entirely equivalent, to the original English versions. The parameters from these two-group calibrations can be used to generate comparable bank scores across the two language versions. In this study, we developed a Spanish version of the PROMIS smoking toolkit, which was originally designed and developed for English speakers. With the growing Spanish-speaking population, it is important to make the toolkit more accessible by translating the items and calibrating the Spanish version to be comparable with English-language scores. This study

  7. Separation index and fit items of creative thinking skills assessment

    OpenAIRE

    Andi Ulfa Tenri Pada; Badrun Kartowagiran; Bambang Subali

    2016-01-01

    This article discusses the evaluation results of the separation index and fit item of creative thinking skills assessment that supports the conation aspect of prospective biology teachers in Aceh. This assessment consists of 37 items of divergent tasks, which is the application of human physiology courses that support the conation aspects. The participants were selected from the Biology Education Program, Faculty of Teacher Training and Education, Syiah Kuala University. The data were analyze...

  8. Analysis of Frequent Item set Mining on Variant Datasets

    OpenAIRE

    Henry Alexander; Rohit Bansal; Robin Singh Bhadoria

    2011-01-01

    Association rule mining is the process of discovering relationships among the data items in large database. It is one of the most important problems in the field of data mining. Finding frequent itemsets is one of the most computationally expensive tasks in association rule mining. The classical frequent itemset mining approaches mine the frequent itemsets from the database where presence of an item in a transaction is certain. Frequent itemset mining under uncertain data model is a new area ...

  9. Learning Item Trees for Probabilistic Modelling of Implicit Feedback

    OpenAIRE

    Mnih, Andriy; Teh, Yee Whye

    2011-01-01

    User preferences for items can be inferred from either explicit feedback, such as item ratings, or implicit feedback, such as rental histories. Research in collaborative filtering has concentrated on explicit feedback, resulting in the development of accurate and scalable models. However, since explicit feedback is often difficult to collect it is important to develop effective models that take advantage of the more widely available implicit feedback. We introduce a probabilistic approach to ...

  10. A Rasch Analysis of Grammatical Difficulty : What Influences Item Difficulty?

    OpenAIRE

    Atsuko, Nishitani; Kyoto Sangyo University

    2014-01-01

    This study investigated the difficulty order of 38 grammar structures obtained from an analysis of multiple-choice items using a Rasch analysis. The participants were 872 Japanese university students, whose TOEIC scores ranged from 200 to 875. The difficulty order of the 38 structures was displayed according to their Rasch difficulty estimates. This study also demonstrated the difficulty of writing items testing the knowledge of the same grammar point that show similar Rasch difficulty estima...

  11. Item response analysis of the inventory of depressive symptomatology

    OpenAIRE

    Bernstein, Ira H; Rush, A John; Carmody, Thomas J; Woo, Ada; Trivedi, Madhukar H

    2006-01-01

    Background: Both the clinician (IDS-C30) and self-report (IDS-SR30) versions of the 30-item Inventory of Depressive Symptomatology have acceptable psychiatric properties and have been used in various clinical studies. These two scales, however, have not been compared using item response theory (IRT) methods to determine whether the standard scoring methods are optimal. Methods: Data were derived from 428 adult public sector outpatients with nonpsychotic major depressive disorder. The IDS-C30 ...

  12. Gesture as a window onto children's number knowledge.

    Science.gov (United States)

    Gunderson, Elizabeth A; Spaepen, Elizabet; Gibson, Dominic; Goldin-Meadow, Susan; Levine, Susan C

    2015-11-01

    Before learning the cardinal principle (knowing that the last word reached when counting a set represents the size of the whole set), children do not use number words accurately to label most set sizes. However, it remains unclear whether this difficulty reflects a general inability to conceptualize and communicate about number, or a specific problem with number words. We hypothesized that children's gestures might reflect knowledge of number concepts that they cannot yet express in speech, particularly for numbers they do not use accurately in speech (numbers above their knower-level). Number gestures are iconic in the sense that they are item-based (i.e., each finger maps onto one item in a set) and therefore may be easier to map onto sets of objects than number words, whose forms do not map transparently onto the number of items in a set and, in this sense, are arbitrary. In addition, learners in transition with respect to a concept often produce gestures that convey different information than the accompanying speech. We examined the number words and gestures 3- to 5-year-olds used to label small set sizes exactly (1-4) and larger set sizes approximately (5-10). Children who had not yet learned the cardinal principle were more than twice as accurate when labeling sets of 2 and 3 items with gestures than with words, particularly if the values were above their knower-level. They were also better at approximating set sizes 5-10 with gestures than with words. Further, gesture was more accurate when it differed from the accompanying speech (i.e., a gesture-speech mismatch). These results show that children convey numerical information in gesture that they cannot yet convey in speech, and raise the possibility that number gestures play a functional role in children's development of number concepts. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Making decisions from numbers

    Energy Technology Data Exchange (ETDEWEB)

    Somers, E.

    1987-03-01

    Regulatory agencies require numbers to provide health protection. The manner in which these numbers are derived from animal experiments and human epidemiology is considered together with the limitations and inadequacies of these numbers. Some recent examples of risk assessment in Canada are given including asbestos, drinking water, and indoor air quality. The value of these numbers in providing a measure of the hazard in a wider perspective is stressed, although they can never be the sole determinant of public policy.

  14. MMPI-2 Item Endorsements in Dissociative Identity Disorder vs. Simulators.

    Science.gov (United States)

    Brand, Bethany L; Chasson, Gregory S; Palermo, Cori A; Donato, Frank M; Rhodes, Kyle P; Voorhees, Emily F

    2016-03-01

    Elevated scores on some MMPI-2 (Minnesota Multiphasic Inventory-2) validity scales are common among patients with dissociative identity disorder (DID), which raises questions about the validity of their responses. Such patients show elevated scores on atypical answers (F), F-psychopathology (Fp), atypical answers in the second half of the test (FB), schizophrenia (Sc), and depression (D) scales, with Fp showing the greatest utility in distinguishing them from coached and uncoached DID simulators. In the current study, we investigated the items on the MMPI-2 F, Fp, FB, Sc, and D scales that were most and least commonly endorsed by participants with DID in our 2014 study and compared these responses with those of coached and uncoached DID simulators. The comparisons revealed that patients with DID most frequently endorsed items related to dissociation, trauma, depression, fearfulness, conflict within family, and self-destructiveness. The coached group more successfully imitated item endorsements of the DID group than did the uncoached group. However, both simulating groups, especially the uncoached group, frequently endorsed items that were uncommonly endorsed by the DID group. The uncoached group endorsed items consistent with popular media portrayals of people with DID being violent, delusional, and unlawful. These results suggest that item endorsement patterns can provide useful information to clinicians making determinations about whether an individual is presenting with DID or feigning. © 2016 American Academy of Psychiatry and the Law.

  15. Promoting cold-start items in recommender systems.

    Science.gov (United States)

    Liu, Jin-Hu; Zhou, Tao; Zhang, Zi-Ke; Yang, Zimo; Liu, Chuang; Li, Wei-Min

    2014-01-01

    As one of the major challenges, cold-start problem plagues nearly all recommender systems. In particular, new items will be overlooked, impeding the development of new products online. Given limited resources, how to utilize the knowledge of recommender systems and design efficient marketing strategy for new items is extremely important. In this paper, we convert this ticklish issue into a clear mathematical problem based on a bipartite network representation. Under the most widely used algorithm in real e-commerce recommender systems, the so-called item-based collaborative filtering, we show that to simply push new items to active users is not a good strategy. Interestingly, experiments on real recommender systems indicate that to connect new items with some less active users will statistically yield better performance, namely, these new items will have more chance to appear in other users' recommendation lists. Further analysis suggests that the disassortative nature of recommender systems contributes to such observation. In a word, getting in-depth understanding on recommender systems could pave the way for the owners to popularize their cold-start products with low costs.

  16. Promoting Cold-Start Items in Recommender Systems

    Science.gov (United States)

    Liu, Jin-Hu; Zhou, Tao; Zhang, Zi-Ke; Yang, Zimo; Liu, Chuang; Li, Wei-Min

    2014-01-01

    As one of the major challenges, cold-start problem plagues nearly all recommender systems. In particular, new items will be overlooked, impeding the development of new products online. Given limited resources, how to utilize the knowledge of recommender systems and design efficient marketing strategy for new items is extremely important. In this paper, we convert this ticklish issue into a clear mathematical problem based on a bipartite network representation. Under the most widely used algorithm in real e-commerce recommender systems, the so-called item-based collaborative filtering, we show that to simply push new items to active users is not a good strategy. Interestingly, experiments on real recommender systems indicate that to connect new items with some less active users will statistically yield better performance, namely, these new items will have more chance to appear in other users' recommendation lists. Further analysis suggests that the disassortative nature of recommender systems contributes to such observation. In a word, getting in-depth understanding on recommender systems could pave the way for the owners to popularize their cold-start products with low costs. PMID:25479013

  17. Item response analysis of the inventory of depressive symptomatology

    Science.gov (United States)

    Bernstein, Ira H; Rush, A John; Carmody, Thomas J; Woo, Ada; Trivedi, Madhukar H

    2006-01-01

    Background: Both the clinician (IDS-C30) and self-report (IDS-SR30) versions of the 30-item Inventory of Depressive Symptomatology have acceptable psychiatric properties and have been used in various clinical studies. These two scales, however, have not been compared using item response theory (IRT) methods to determine whether the standard scoring methods are optimal. Methods: Data were derived from 428 adult public sector outpatients with nonpsychotic major depressive disorder. The IDS-C30 and IDS-SR30 were compared using Samejima’s graded response model. Results: A model was constructed jointly fitting the IDS-C30 and IDS-SR30. An improvement in scale performance was obtained by grouping selected items into domains (specifically sleep, psychomotor, and appetite/weight domains) analogous to the standard scoring of the 16-item Quick Inventory of Depressive Symptomatology. Conclusions: For the IDS-C30 and IDS-SR30, standard scoring (ie, computing total score using all individual items) provides simplicity, comparability to published data, and a basis for clinical decision making. The revised scoring method, however, improves the utility of both scales when comparing groups as it provides explicit tests of item parameters. PMID:18159226

  18. Survey on fusible numbers

    OpenAIRE

    Xu, Junyan

    2012-01-01

    We point out that the recursive formula that appears in Erickson's presentation "Fusible Numbers" is incorrect, and pose an alternate conjecture about the structure of fusible numbers. Although we are unable to solve the conjecture, we succeed in establishing some basic properties of fusible numbers. We suggest some possible approaches to the conjecture, and list further problems in the final chapter.

  19. Discovery: Prime Numbers

    Science.gov (United States)

    de Mestre, Neville

    2008-01-01

    Prime numbers are important as the building blocks for the set of all natural numbers, because prime factorisation is an important and useful property of all natural numbers. Students can discover them by using the method known as the Sieve of Eratosthenes, named after the Greek geographer and astronomer who lived from c. 276-194 BC. Eratosthenes…

  20. Analytic number theory

    CERN Document Server

    Matsumoto, Kohji

    2002-01-01

    The book includes several survey articles on prime numbers, divisor problems, and Diophantine equations, as well as research papers on various aspects of analytic number theory such as additive problems, Diophantine approximations and the theory of zeta and L-function Audience Researchers and graduate students interested in recent development of number theory

  1. Damage of office supply, personal use items, and over-the-counter medical devices after sterilization by ethylene oxide gas, electron beam, and gamma radiation.

    Science.gov (United States)

    Lucas, Anne D; Merritt, Katharine; Hitchins, Victoria M

    2004-01-01

    After letters containing Bacillus anthracis spores entered the U.S. mail in 2001, a problem emerged regarding how to decontaminate the letters, packages, and personal items in offices that received these letters. The effects of three sterilization methods (i.e. ethylene oxide gas [EO], electron beam [e-beam] radiation, and gamma radiation) were evaluated for a variety of office supply and equipment, personal use items, and over-the-counter medical devices. No single sterilization method was suitable for all items that could be mailed or found in an office. Damage or discoloration was evident for some items by each sterilization method. There were changes in the color of certain items, such as some of the packaging material, some pacifiers, some of the fabrics, and the nylon stockings after e-beam and gamma radiation. Both e-beam and gamma radiation damaged all film samples. Following EO sterilization and normal aeration, there were a number of samples with high (above 250 microg/g) levels of EO and samples with detectable ethylene chlorohydrin levels. The data would suggest that certain items exposed to EO sterilization must be further aerated prior to use, or discarded. Generic descriptions of products (such as plastics) or grouping of items (such as condoms) were not sufficient to predict what is safe in terms of EO residual levels remaining on an item. Successful decontamination of a wide variety of items will require careful selection of different sterilization methods.

  2. The VHI-10 and VHI Item Reduction Translations-Are we all Speaking the Same Language?

    Science.gov (United States)

    Gilbert, Mark R; Gartner-Schmidt, Jackie L; Rosen, Clark A

    2017-03-01

    The Vocal Handicap Index-10 (VHI-10) was designed as an item reduction of the original VHI to provide a quick, reliable, and quantifiable measure of patients' own vocal handicap perception. Many translations of the VHI-10 have been produced, but methodologies of translation vary between articles and do not always mirror that of the English VHI-10. This discrepancy leads to confusion about normative values and the applicability of published data in non-English-speaking cultures. This article examines the various item reductions of the VHI-10 from the VHI and the differing methodologies of translation of the VHI-10. This is an invited review article. Published item reductions and translations of the VHI-10 were reviewed. Normative values for each translation, where available, were calculated. The World Health Organization recommendations for the translation of instruments are reviewed. There are substantial differences between the original VHI-10 (created and published in American English) and many of the translations of the VHI-10 and other proposed item reductions, both in the actual questions used and the order of the questions. We have to conclude that for a number of the non-English VHI-10/VHI reductions, the instruments are not equivalent, meaning the results from different languages are not comparable. Our recommendation for future patient-reported instrument translations is to translate and validate the instrument according to the World Health Organization protocol while maintaining item consistency and order, allowing studies to be better focused and decrease unnecessary replication of well-performed studies, as well as allowing metadata to be combined from different countries and cultures. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  3. Analysis of Chemical Composition of Non-Ferrous Metal Items from the Ananyino Burial Ground

    Directory of Open Access Journals (Sweden)

    Saprykina Irina А.

    2016-03-01

    Full Text Available The article presents results of an analysis conducted by the authors in order to study chemical composition of items from non-ferrous metals found on the Ananyino burial ground. A number of research methods, including OES, XRF and TXRF was applied to study a selection of 387 samples of arrow- and spearheads, celts, tail-pieces, warhammers, poleaxes, knives and daggers, as well as items of attire and jewelry, some sporadic details of harness and bridle. The fi ndings are quite comparable. The results were classifi ed by the geochemical principle of 1,0% alloyage threshold. It was found out that the sample primarily consists of copper items, including “pure” copper and copper with a wide range of trace elements (particularly, Ni, As, Sb. The core (48% consists of copper items with traces of antimony and arsenic, or “pure” copper (7%, tin or triple bronze (40%; it also includes some other types of alloys based on copper or silver (5%. As the analysis has shown, complex ores seem to be the most probable source of copper. Traditionally, the Urals, the Sayan and the Altay Mountains, Kazakhstan and the Northern Caucasus were regarded as the most probable minefi elds to supply ores to the barren regions of Eastern Europe. While ore sources for products made of metallurgical “pure” copper are localized within the Ural mining and metallurgical region, metal sources for items cast from different groups of alloys (rather than imports of ready-made products require further research.

  4. Using Likert-type and ipsative/forced choice items in sequence to generate a preference.

    Science.gov (United States)

    Ried, L Douglas

    2014-01-01

    Collaboration and implementation of a minimum, standardized set of core global educational and professional competencies seems appropriate given the expanding international evolution of pharmacy practice. However, winnowing down hundreds of competencies from a plethora of local, national and international competency frameworks to select the most highly preferred to be included in the core set is a daunting task. The objective of this paper is to describe a combination of strategies used to ascertain the most highly preferred items among a large number of disparate items. In this case, the items were >100 educational and professional competencies that might be incorporated as the core components of new and existing competency frameworks. Panelists (n = 30) from the European Union (EU) and United States (USA) were chosen to reflect a variety of practice settings. Each panelist completed two electronic surveys. The first survey presented competencies in a Likert-type format and the second survey presented many of the same competencies in an ipsative/forced choice format. Item mean scores were calculated for each competency, the competencies were ranked, and non-parametric statistical tests were used to ascertain the consistency in the rankings achieved by the two strategies. This exploratory study presented over 100 competencies to the panelists in the beginning. The two methods provided similar results, as indicated by the significant correlation between the rankings (Spearman's rho = 0.30, P competency preferences because the panelists could not rate them equally by design. While this strategy was used for the selection of professional educational competencies in this exploratory study, it is applicable in other situations where a smaller set of highly preferred items might be selected from a large list of choices in other areas of inquiry (e.g., patient reported outcomes). Copyright © 2014 Elsevier Inc. All rights reserved.

  5. A Queueing System with Heterogeneous Impatient Customers and Consumable Additional Items

    Directory of Open Access Journals (Sweden)

    Baek Janghyun

    2017-06-01

    Full Text Available A single-server queueing system with a marked Markovian arrival process of heterogeneous customers is considered. Type-1 customers have limited preemptive priority over type-2 customers. There is an infinite buffer for type-2 customers and no buffer for type-1 customers. There is also a finite buffer (stock for consumable additional items (semi-products, half-stocks, etc. which arrive according to the Markovian arrival process. Service of a customer requires a fixed number of consumable additional items depending on the type of the customer. The service time has a phase-type distribution depending on the type of the customer. Customers in the buffer are impatient and may leave the system without service after an exponentially distributed amount of waiting time. Aiming to minimize the loss probability of type-1 customers and maximize throughput of the system, a threshold strategy of admission to service of type-2 customers is offered. Service of type-2 customer can start only if the server is idle and the number of consumable additional items in the stock exceeds the fixed threshold. Stationary distributions of the system states and the waiting time are computed. In the numerical example, we show some interesting effects and illustrate a possibility of application of the presented results for solution of optimization problems.

  6. Applied number theory

    CERN Document Server

    Niederreiter, Harald

    2015-01-01

    This textbook effectively builds a bridge from basic number theory to recent advances in applied number theory. It presents the first unified account of the four major areas of application where number theory plays a fundamental role, namely cryptography, coding theory, quasi-Monte Carlo methods, and pseudorandom number generation, allowing the authors to delineate the manifold links and interrelations between these areas.  Number theory, which Carl-Friedrich Gauss famously dubbed the queen of mathematics, has always been considered a very beautiful field of mathematics, producing lovely results and elegant proofs. While only very few real-life applications were known in the past, today number theory can be found in everyday life: in supermarket bar code scanners, in our cars’ GPS systems, in online banking, etc.  Starting with a brief introductory course on number theory in Chapter 1, which makes the book more accessible for undergraduates, the authors describe the four main application areas in Chapters...

  7. Few items in the thyroid-related quality of life instrument ThyPRO exhibited differential item functioning

    DEFF Research Database (Denmark)

    Watt, Torquil; Grønvold, Mogens; Hegedüs, Laszlo

    2014-01-01

    To evaluate the extent of differential item functioning (DIF) within the thyroid-specific quality of life patient-reported outcome measure, ThyPRO, according to sex, age, education and thyroid diagnosis.......To evaluate the extent of differential item functioning (DIF) within the thyroid-specific quality of life patient-reported outcome measure, ThyPRO, according to sex, age, education and thyroid diagnosis....

  8. Evaluation of the Hospital Anxiety and Depression Scale (HADS) in screening stroke patients for symptoms: Item Response Theory (IRT) analysis.

    Science.gov (United States)

    Ayis, Salma A; Ayerbe, Luis; Ashworth, Mark; DA Wolfe, Charles

    2018-03-01

    Variations have been reported in the number of underlying constructs and choice of thresholds that determine caseness of anxiety and /or depression using the Hospital Anxiety and Depression scale (HADS). This study examined the properties of each item of HADS as perceived by stroke patients, and assessed the information these items convey about anxiety and depression between 3 months to 5 years after stroke. The study included 1443 stroke patients from the South London Stroke Register (SLSR). The dimensionality of HADS was examined using factor analysis methods, and items' properties up to 5 years after stroke were tested using Item Response Theory (IRT) methods, including graded response models (GRMs). The presence of two dimensions of HADS (anxiety and depression) for stroke patients was confirmed. Items that accurately inferred about the severity of anxiety and depression, and offered good discrimination of caseness were identified as "I can laugh and see the funny side of things" (Q4) and "I get sudden feelings of panic" (Q13), discrimination 2.44 (se = 0.26), and 3.34 (se = 0.35), respectively. Items that shared properties, hence replicate inference were: "I get a sort of frightened feeling as if something awful is about to happen" (Q3), "I get a sort of frightened feeling like butterflies in my stomach" (Q6), and "Worrying thoughts go through my mind" (Q9). Item properties were maintained over time. Approximately 20% of patients were lost to follow up. A more concise selection of items based on their properties, would provide a precise approach for screening patients and for an optimal allocation of patients into clinical trials. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Modified economic order quantity (EOQ model for items with imperfect quality: Game-theoretical approaches

    Directory of Open Access Journals (Sweden)

    Milad Elyasi

    2014-04-01

    Full Text Available In the recent decade, studying the economic order quantity (EOQ models with imperfect quality has appealed to many researchers. Only few papers are published discussing EOQ models with imperfect items in a supply chain. In this paper, a two-echelon decentralized supply chain consisting of a manufacture and a supplier that both face just in time (JIT inventory problem is considered. It is sought to find the optimal number of the shipments and the quantity of each shipment in a way that minimizes the both manufacturer’s and the supplier’s cost functions. To the authors’ best knowledge, this is the first paper that deals with imperfect items in a decentralized supply chain. Thereby, three different game theoretical solution approaches consisting of two non-cooperative games and a cooperative game are proposed. Comparing the results of three different scenarios with those of the centralized model, the conclusions are drawn to obtain the best approach.

  10. Entry-Item-Quantity-ABC Analysis-Based Multitype Cigarette Fast Sorting System

    Directory of Open Access Journals (Sweden)

    Ying Zhao

    2012-01-01

    Full Text Available Numerous items, small order, and frequent delivery are the characteristics of many distribution centers. Such characteristics generally increase the operating costs of the distribution center. To remedy this problem, this study employs the Entry-Item-Quantity (EIQ method to identify the characteristic of the cigarette distribution center and further analyzes the importance degree of customers and the frequently ordered products by means of EQ/EN/IQ-B/IK statistic charts. Based on these analyses as well as the total replenishment cost optimization model, multipicking strategies and combined multitype picking equipment allocation is then formulated accordingly. With such design scheme, the cigarette picking costs of the distribution center are expected to reduce. Finally, the specific number of equipment is figured out in order to meet the capability demand of the case cigarette distribution center.

  11. An EOQ model for imperfect quality items with partial backordering under screening errors

    Directory of Open Access Journals (Sweden)

    Ehsan Sharifi

    2015-12-01

    Full Text Available In practice, when a lot size received, an inspection process is necessary to identify the defective items. In addition, the inspection process itself is not error-free and it may contain misclassification errors. In this paper, an economic order quantity model for imperfect quality items with partial backordering under screening errors is studied. The objective is to maximize the expected annual profit by optimizing the order size and the maximum number of backorder units. Also, the aim of this paper is to develop a general and practical model that is more realistic in the competitive commercial situations. For authenticity of the developed model, a case study and a numerical example are illustrated, and the sensitivity analysis is also carried out.

  12. Optimal number of strata for the stratified methods in computerized adaptive testing.

    Science.gov (United States)

    Barrada, Juan Ramón; Abad, Francisco José; Olea, Julio

    2014-01-01

    Test security can be a major problem in computerized adaptive testing, as examinees can share information about the items they receive. Of the different item selection rules proposed to alleviate this risk, stratified methods are among those that have received most attention. In these methods, only low discriminative items can be presented at the beginning of the test and the mean information of the items increases as the test goes on. To do so, the item bank must be divided into several strata according to the information of the items. To date, there is no clear guidance about the optimal number of strata into which the item bank should be split. In this study, we will simulate conditions with different numbers of strata, from 1 (no stratification) to a number of strata equal to test length (maximum level of stratification) while manipulating the maximum exposure rate that no item should surpass (r max ) in its whole domain. In this way, we can plot the relation between test security and accuracy, making it possible to determine the number of strata that leads to better security while holding constant measurement accuracy. Our data indicates that the best option is to stratify into as many strata as possible.

  13. The Relationship between Mathematical Knowledge of Numbers and Operations and Mathematics Beliefs of Prospective Teachers

    Science.gov (United States)

    Stiegelmeyer, Cindy

    2012-01-01

    This study surveyed 82 preservice elementary teachers using items from an instrument designed to predict student achievement based on a teacher's mathematics knowledge for teaching (MKT) in numbers and operations concepts. Additional mathematics beliefs items asked participants to rate their level of agreement with math myths and math anxiety…

  14. Suspect/Counterfeit Items Information Guide for Subcontractors/Suppliers

    Energy Technology Data Exchange (ETDEWEB)

    Tessmar, Nancy D. [Los Alamos National Laboratory; Salazar, Michael J. [Los Alamos National Laboratory

    2012-09-18

    Counterfeiting of industrial and commercial grade items is an international problem that places worker safety, program objectives, expensive equipment, and security at risk. In order to prevent the introduction of Suspect/Counterfeit Items (S/CI), this information sheet is being made available as a guide to assist in the implementation of S/CI awareness and controls, in conjunction with subcontractor's/supplier's quality assurance programs. When it comes to counterfeit goods, including industrial materials, items, and equipment, no market is immune. Some manufactures have been known to misrepresent their products and intentionally use inferior materials and processes to manufacture substandard items, whose properties can significantly cart from established standards and specifications. These substandard items termed by the Department of Energy (DOE) as S/CI, pose immediate and potential threats to the safety of DOE and contractor workers, the public, and the environment. Failure of certain systems and processes caused by an S/CI could also have national security implications at Los Alamos National Laboratory (LANL). Nuclear Safety Rules (federal Laws), DOE Orders, and other regulations set forth requirements for DOE contractors to implement effective controls to assure that items and services meet specified requirements. This includes techniques to implement and thereby minimizing the potential threat of entry of S/CI to LANL. As a qualified supplier of goods or services to the LANL, your company will be required to establish and maintain effective controls to prevent the introduction of S/CI to LANL. This will require that your company warrant that all items (including their subassemblies, components, and parts) sold to LANL are genuine (i.e. not counterfeit), new, and unused, and conform to the requirements of the LANL purchase orders/contracts unless otherwise approved in writing to the Los Alamos National Security (LANS) contract administrator

  15. [Management of multidimensional clinical scores: which solutions for items aggregation?].

    Science.gov (United States)

    Benaïm, C; Daurès, J P; Petiot, S; Pélissier, J

    2001-12-01

    Clinical evaluation is a multifactorial process producing as many clinical scores as there are clinical dimensions. For a medicoeconomical analysis however, a single global score would be most useful. The aim of this work was to examine methods allowing relative quantification of items on multidimensional clinical scores in order to determine an appropriate solution for weighted items aggregation. Several techniques for item weighting, developed as part of a multi-criteria decision-making tool (AMCD Aide Multi-Critère à la Décision), were examined. Two methods were applied to multidimensional assessment of disability in order to estimate the weight that should be assigned to each of its six items before aggregation in a unique score. The AHP method was used with an interview of 20 functional rehabilitation specialists. The Diakoulaki method was based on the observation of thirty patients with chronic back pain and in thirty patients with vascular hemiplegia. The three weighting schemes were very different from the uniform weighting and were not correlated with each other. The items best weighted by the AHP method were "physical independence" and "mobility". For the Diakoulaki method, they were "social integration" and "economic independence" for the chronic back pain patients, and "awareness of the outside world" and "economic independence" for the vascular hemiplegia patients. Application of these three weighting schemes to theoretical patients produced very different assessments of global disability. Weighting schemes are useful to quantify the relative importance of individual clinical items. The choice of the weighting method is determinant and depends on the objective of the investigator. If the objective is a global score, the first step is to estimate the weight of the individual items, either when applying a validation process for a new multidimensional clinical score, or secondarily to adapt a validated score to a particular protocol.

  16. The Impact of Model Misspecification on Parameter Estimation and Item-Fit Assessment in Log-Linear Diagnostic Classification Models

    Science.gov (United States)

    Kunina-Habenicht, Olga; Rupp, Andre A.; Wilhelm, Oliver

    2012-01-01

    Using a complex simulation study we investigated parameter recovery, classification accuracy, and performance of two item-fit statistics for correct and misspecified diagnostic classification models within a log-linear modeling framework. The basic manipulated test design factors included the number of respondents (1,000 vs. 10,000), attributes (3…

  17. Using a Linear Regression Method to Detect Outliers in IRT Common Item Equating

    Science.gov (United States)

    He, Yong; Cui, Zhongmin; Fang, Yu; Chen, Hanwei

    2013-01-01

    Common test items play an important role in equating alternate test forms under the common item nonequivalent groups design. When the item response theory (IRT) method is applied in equating, inconsistent item parameter estimates among common items can lead to large bias in equated scores. It is prudent to evaluate inconsistency in parameter…

  18. A Stepwise Test Characteristic Curve Method to Detect Item Parameter Drift

    Science.gov (United States)

    Guo, Rui; Zheng, Yi; Chang, Hua-Hua

    2015-01-01

    An important assumption of item response theory is item parameter invariance. Sometimes, however, item parameters are not invariant across different test administrations due to factors other than sampling error; this phenomenon is termed item parameter drift. Several methods have been developed to detect drifted items. However, most of the…

  19. The impact of parameter estimation on computerized adaptive testing with item cloning

    NARCIS (Netherlands)

    Glas, Cornelis A.W.

    Item cloning techniques can greatly reduce the cost of item writing and enhance the flexibility of item presentation. An important consequence of cloning is that it may cause variability in the item parameters. Recently, Glas and van der Linden (in press, 2005) proposed a multilevel item response

  20. An NCME Instructional Module on Latent DIF Analysis Using Mixture Item Response Models

    Science.gov (United States)

    Cho, Sun-Joo; Suh, Youngsuk; Lee, Woo-yeol

    2016-01-01

    The purpose of this ITEMS module is to provide an introduction to differential item functioning (DIF) analysis using mixture item response models. The mixture item response models for DIF analysis involve comparing item profiles across latent groups, instead of manifest groups. First, an overview of DIF analysis based on latent groups, called…

  1. REVIEW OF IRRATIONAL NUMBERS

    Directory of Open Access Journals (Sweden)

    Hafnani Hafnani

    2015-04-01

    Full Text Available Study of the set properties is simple and rarely investigated at the Department of Mathematics. This paper examines some set properties on the irrational numbers. The study is about the properties applying to the real numbers which are a complete ordered field. However, the results of this study show that those properties do not imply to the irrational numbers, but the ordered property. The prove of the irrational numberby some examples is demonstrated in this study.

  2. The simple complex numbers

    OpenAIRE

    Zalesny, Jaroslaw

    2008-01-01

    A new simple geometrical interpretation of complex numbers is presented. It differs from their usual interpretation as points in the complex plane. From the new point of view the complex numbers are rather operations on vectors than points. Moreover, in this approach the real, imaginary and complex numbers have similar interpretation. They are simply some operations on vectors. The presented interpretation is simpler, more natural, and better adjusted to possible applications in geometry and ...

  3. Numbers, sequences and series

    CERN Document Server

    Hirst, Keith

    1994-01-01

    Number and geometry are the foundations upon which mathematics has been built over some 3000 years. This book is concerned with the logical foundations of number systems from integers to complex numbers. The author has chosen to develop the ideas by illustrating the techniques used throughout mathematics rather than using a self-contained logical treatise. The idea of proof has been emphasised, as has the illustration of concepts from a graphical, numerical and algebraic point of view. Having laid the foundations of the number system, the author has then turned to the analysis of infinite proc

  4. Predicting Lotto Numbers

    OpenAIRE

    Jorgensen, C.B.; Suetens, S.; Tyran, J.R.

    2011-01-01

    We investigate the "law of small numbers" using a unique panel data set on lotto gambling. Because we can track individual players over time, we can measure how they react to outcomes of recent lotto drawings. We can therefore test whether they behave as if they believe they can predict lotto numbers based on recent drawings. While most players pick the same set of numbers week after week without regards of numbers drawn or anything else, we find that those who do change, act on average in th...

  5. The adventure of numbers

    CERN Document Server

    Godefroy, Gilles

    2004-01-01

    Numbers are fascinating. The fascination begins in childhood, when we first learn to count. It continues as we learn arithmetic, algebra, geometry, and so on. Eventually, we learn that numbers not only help us to measure the world, but also to understand it and, to some extent, to control it. In The Adventure of Numbers, Gilles Godefroy follows the thread of our expanding understanding of numbers to lead us through the history of mathematics. His goal is to share the joy of discovering and understanding this great adventure of the mind. The development of mathematics has been punctuated by a n

  6. Predicting Lotto Numbers

    DEFF Research Database (Denmark)

    Jørgensen, Claus Bjørn; Suetens, Sigrid; Tyran, Jean-Robert

    We investigate the “law of small numbers” using a unique panel data set on lotto gambling. Because we can track individual players over time, we can measure how they react to outcomes of recent lotto drawings. We can therefore test whether they behave as if they believe they can predict lotto...... numbers based on recent drawings. While most players pick the same set of numbers week after week without regards of numbers drawn or anything else, we find that those who do change, act on average in the way predicted by the law of small numbers as formalized in recent behavioral theory. In particular...

  7. Beurling generalized numbers

    CERN Document Server

    Diamond, Harold G; Cheung, Man Ping

    2016-01-01

    "Generalized numbers" is a multiplicative structure introduced by A. Beurling to study how independent prime number theory is from the additivity of the natural numbers. The results and techniques of this theory apply to other systems having the character of prime numbers and integers; for example, it is used in the study of the prime number theorem (PNT) for ideals of algebraic number fields. Using both analytic and elementary methods, this book presents many old and new theorems, including several of the authors' results, and many examples of extremal behavior of g-number systems. Also, the authors give detailed accounts of the L^2 PNT theorem of J. P. Kahane and of the example created with H. L. Montgomery, showing that additive structure is needed for proving the Riemann hypothesis. Other interesting topics discussed are propositions "equivalent" to the PNT, the role of multiplicative convolution and Chebyshev's prime number formula for g-numbers, and how Beurling theory provides an interpretation of the ...

  8. Intuitive numbers guide decisions

    Directory of Open Access Journals (Sweden)

    Ellen Peters

    2008-12-01

    Full Text Available Measuring reaction times to number comparisons is thought to reveal a processing stage in elementary numerical cognition linked to internal, imprecise representations of number magnitudes. These intuitive representations of the mental number line have been demonstrated across species and human development but have been little explored in decision making. This paper develops and tests hypotheses about the influence of such evolutionarily ancient, intuitive numbers on human decisions. We demonstrate that individuals with more precise mental-number-line representations are higher in numeracy (number skills consistent with previous research with children. Individuals with more precise representations (compared to those with less precise representations also were more likely to choose larger, later amounts over smaller, immediate amounts, particularly with a larger proportional difference between the two monetary outcomes. In addition, they were more likely to choose an option with a larger proportional but smaller absolute difference compared to those with less precise representations. These results are consistent with intuitive number representations underlying: a perceived differences between numbers, b the extent to which proportional differences are weighed in decisions, and, ultimately, c the valuation of decision options. Human decision processes involving numbers important to health and financial matters may be rooted in elementary, biological processes shared with other species.

  9. Is a Single-Item Operative Performance Rating Sufficient?

    Science.gov (United States)

    Williams, Reed G; Verhulst, Steven; Mellinger, John D; Dunnington, Gary L

    2015-01-01

    A valid measure of resident operative performance ability requires direct observation and accurate rating of multiple resident performances under the normal range of operating conditions. The challenge is to create an operative performance rating (OPR) system that: is easy to use, encourages completion of many ratings immediately after performances and minimally disrupts supervising surgeons' work days. The purpose of this study was to determine whether a score based on a single-item overall OPR provides a valid and stable appraisal of resident operative performances. A retrospective comparison of a single-item OPR with a gold-standard rating based on multiple procedure-specific and general OPR items. Data were collected in the general surgery residency program at Southern Illinois University from 2001 through 2012. Assessments of 1033 operative performances (3 common procedures, 2 laparoscopic, and 1 open) by general surgery residents were collected. OPRs based on single-item overall performance scale scores were compared with gold-standard ratings for the same performances. Differences in performance scores using the 2 scales averaged 0.02 points (5-point scale). Correlations of the single-item and gold-standard scale scores averaged 0.95. Based on generalizability analyses of laparoscopic cholecystectomy ratings, each instrument required 5 observations to achieve reliabilities of 0.80 and 11 observations to achieve reliabilities of 0.90. Only 4.4% of single-item ratings misclassified the performance when compared with the gold-standard rating and all misclassifications were near misses. For 80% of misclassified ratings, single-item ratings were lower. Single-item operative performance measures produced ratings that were virtually identical to gold-standard scale ratings. Misclassifications occurred infrequently and were minor in magnitude. Ratings using the single-item scale: take less time to complete, should increase the sample of procedures rated, and

  10. Littlewood and Number Theory

    Indian Academy of Sciences (India)

    IAS Admin

    doctoral thesis, R Balasubramanian [8] improved this further and showed that one can take θ = 1/3. 4. Littlewood's Problem on Diophantine Ap- proximation. For any real number x, let ||x|| denote the distance of x to the nearest integer. For any pair of real numbers α, β, Littlewood conjectured that lim inf n→∞ n||nα||||nβ|| = 0.

  11. The Class Number Problem

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 7. The Class Number Problem - An Introduction to Algebraic Number Theory. Rajat Tandon. General Article Volume 3 Issue 7 July 1998 pp 28-37. Fulltext. Click here to view fulltext PDF. Permanent link:

  12. Predicting Lotto Numbers

    DEFF Research Database (Denmark)

    Suetens, Sigrid; Galbo-Jørgensen, Claus B.; Tyran, Jean-Robert Karl

    2016-01-01

    We investigate the ‘law of small numbers’ using a data set on lotto gambling that allows us to measure players’ reactions to draws. While most players pick the same set of numbers week after week, we find that those who do change react on average as predicted by the law of small numbers...

  13. The Congruent Number Problem

    Indian Academy of Sciences (India)

    In Mathematics, especially number theory, one of- .... pear on the list. Continuing in this way ·would exhaust one's computing resources, not to mention one's patience! Also, this procedure is of no avail if n is not a congruent number. ..... If p and q are odd primes, then the Legendre symbol (p/q) is 1 if P is a quadratic residue.

  14. Avogadro's Number Ferromagnetically

    Science.gov (United States)

    Houari, Ahmed

    2010-01-01

    Avogadro's number, usually denoted by N[subscript A], plays a fundamental role in both physics and chemistry. It defines the extremely useful concept of the mole, which is the base unit of the amount of matter in the international system of units. The fundamental character of this number can also be illustrated by its appearance in the definitions…

  15. Coherence number as a discrete quantum resource

    Science.gov (United States)

    Chin, Seungbeom

    2017-10-01

    We introduce a discrete coherence monotone named the coherence number, which is a generalization of the coherence rank to mixed states. After defining the coherence number in a manner similar to that of the Schmidt number in entanglement theory, we present a necessary and sufficient condition of the coherence number for a coherent state to be converted to an entangled state of nonzero k concurrence (a member of the generalized concurrence family with 2 ≤k ≤d ). As an application of the coherence number to a practical quantum system, Grover's search algorithm of N items is considered. We show that the coherence number remains N and falls abruptly when the success probability of a searching process becomes maximal. This phenomenon motivates us to analyze the depletion pattern of Cc(N ) (the last member of the generalized coherence concurrence, nonzero when the coherence number is N ), which turns out to be an optimal resource for the process since it is completely consumed to finish the searching task. The generalization of the original Grover algorithm with arbitrary (mixed) initial states is also discussed, which reveals the boundary condition for the coherence to be monotonically decreasing under the process.

  16. Estimation of a four-parameter item response theory model.

    Science.gov (United States)

    Loken, Eric; Rulison, Kelly L

    2010-11-01

    We explore the justification and formulation of a four-parameter item response theory model (4PM) and employ a Bayesian approach to recover successfully parameter estimates for items and respondents. For data generated using a 4PM item response model, overall fit is improved when using the 4PM rather than the 3PM or the 2PM. Furthermore, although estimated trait scores under the various models correlate almost perfectly, inferences at the high and low ends of the trait continuum are compromised, with poorer coverage of the confidence intervals when the wrong model is used. We also show in an empirical example that the 4PM can yield new insights into the properties of a widely used delinquency scale. We discuss the implications for building appropriate measurement models in education and psychology to model more accurately the underlying response process.

  17. How did Danish students solve the PISA CBAS items?

    DEFF Research Database (Denmark)

    Sørensen, Helene; Andersen, Annemarie Møller

    2009-01-01

    The intention by introducing Computer-based Assessment in Science (CBAS) was to reduce the reading load and to retain the science content. CBAS succeeded in doing this but in the CBAS test results showed a significant gender difference in favour of males. This means that the computer-based test...... is not gender-neutral to the same extent as the paper-and-pencil test. Instead of that the items appear to be more difficult for girls than boys in all three countries which went through CBAS. Within the Danish context we have classified the different items and compared the results with patterns in girls...... explanation for the bigger gender difference in CBAS. The items mediate a gendered impression which influences girls more than boys. This together with the social settings around the test requires a high self confidence to score high in the test....

  18. Directed forgetting of complex pictures in an item method paradigm.

    Science.gov (United States)

    Hauswald, Anne; Kissler, Johanna

    2008-11-01

    An item-cued directed forgetting paradigm was used to investigate the ability to control episodic memory and selectively encode complex coloured pictures. A series of photographs was presented to 21 participants who were instructed to either remember or forget each picture after it was presented. Memory performance was later tested with a recognition task where all presented items had to be retrieved, regardless of the initial instructions. A directed forgetting effect--that is, better recognition of "to-be-remembered" than of "to-be-forgotten" pictures--was observed, although its size was smaller than previously reported for words or line drawings. The magnitude of the directed forgetting effect correlated negatively with participants' depression and dissociation scores. The results indicate that, at least in an item method, directed forgetting occurs for complex pictures as well as words and simple line drawings. Furthermore, people with higher levels of dissociative or depressive symptoms exhibit altered memory encoding patterns.

  19. Differential Weighting of Items to Improve University Admission Test Validity

    Directory of Open Access Journals (Sweden)

    Eduardo Backhoff Escudero

    2001-05-01

    Full Text Available This paper gives an evaluation of different ways to increase university admission test criterion-related validity, by differentially weighting test items. We compared four methods of weighting multiple-choice items of the Basic Skills and Knowledge Examination (EXHCOBA: (1 punishing incorrect responses by a constant factor, (2 weighting incorrect responses, considering the levels of error, (3 weighting correct responses, considering the item’s difficulty, based on the Classic Measurement Theory, and (4 weighting correct responses, considering the item’s difficulty, based on the Item Response Theory. Results show that none of these methods increased the instrument’s predictive validity, although they did improve its concurrent validity. It was concluded that it is appropriate to score the test by simply adding up correct responses.

  20. Significant effects due to rephrasing the Maslach Burnout Inventory's personal accomplishment items.

    NARCIS (Netherlands)

    Bouman, A.M.; Hoogstraten, J.; te Brake, H.

    2002-01-01

    Subjects, 292 Dutch psychology students answering negatively phrased Personal Accomplishment items, reported a more personally competent feeling than subjects answering positively phrased personal accomplishment items. The way of phrasing personal accomplishment items significantly affects the

  1. Policy for the treatment of insulting and sensitive lexical items in the ...

    African Journals Online (AJOL)

    Keywords: policy, treatment, insulting lexical items, sensitive lexical items, dictionary, woordeboek van die afrikaanse taal, simplexes, compounds, expressions, general usage criterion, labelling, synonyms, metalanguage, collocations, editorial usage examples, citations, advisors, racist lexical items, neutral lemmas, ...

  2. Psychometric analysis of the Ten-Item Perceived Stress Scale.

    Science.gov (United States)

    Taylor, John M

    2015-03-01

    Although the 10-item Perceived Stress Scale (PSS-10) is a popular measure, a review of the literature reveals 3 significant gaps: (a) There is some debate as to whether a 1- or a 2-factor model best describes the relationships among the PSS-10 items, (b) little information is available on the performance of the items on the scale, and (c) it is unclear whether PSS-10 scores are subject to gender bias. These gaps were addressed in this study using a sample of 1,236 adults from the National Survey of Midlife Development in the United States II. Based on self-identification, participants were 56.31% female, 77% White, 17.31% Black and/or African American, and the average age was 54.48 years (SD = 11.69). Findings from an ordinal confirmatory factor analysis suggested the relationships among the items are best described by an oblique 2-factor model. Item analysis using the graded response model provided no evidence of item misfit and indicated both subscales have a wide estimation range. Although t tests revealed a significant difference between the means of males and females on the Perceived Helplessness Subscale (t = 4.001, df = 1234, p < .001), measurement invariance tests suggest that PSS-10 scores may not be substantially affected by gender bias. Overall, the findings suggest that inferences made using PSS-10 scores are valid. However, this study calls into question inferences where the multidimensionality of the PSS-10 is ignored. 2015 APA, all rights reserved

  3. The Predictive Validity of the Beck Depression Inventory Suicide Item.

    Science.gov (United States)

    Green, Kelly L; Brown, Gregory K; Jager-Hyman, Shari; Cha, Jason; Steer, Robert A; Beck, Aaron T

    2015-12-01

    The current study examines the predictive validity of the Beck Depression Inventory (BDI) suicide item for death by suicide and suicide attempts. The study included 2 samples: (1) 5,200 psychiatric outpatients who were evaluated between 1975 and 1995 and followed prospectively for up to 20 years (all psychiatric diagnoses based on DSM-III and DSM-III-R), and (2) 119 patients who, between 2000 and 2004, participated in a randomized controlled trial of outpatient Cognitive Therapy for Suicide Prevention after a suicide attempt and were followed for 18 months (all psychiatric diagnoses based on DSM-IV-TR). All patients completed structured diagnostic interviews, as well as the BDI and Scale for Suicide Ideation. Cox regression models demonstrated that the BDI suicide item significantly predicted both deaths by suicide (Wald χ(2)1 = 35.67; P < .001 [N = 5,200]) and repeat suicide attempts (Wald χ(2)1 = 8.82; P < .01 [N = 119]), with each successive rating on the item conferring greater risk. Using receiver operating characteristic (ROC) curves, optimal cutoff scores of 1 and above for suicide and 2 and above for suicide attempts were identified as providing the best balance between sensitivity and specificity. The BDI suicide item is associated with both risk of repeat suicide attempts and death by suicide. The use of the item as a brief, efficient screen for suicide risk in routine clinical care is recommended. Clinicians would then conduct a comprehensive suicide risk assessment in response to a positive screen. Future research examining the item's performance in other at-risk groups (ie, older adults, adolescents, inpatients, etc) is encouraged. © Copyright 2015 Physicians Postgraduate Press, Inc.

  4. An item response theory analysis of the narcissistic personality inventory.

    Science.gov (United States)

    Ackerman, Robert A; Donnellan, M Brent; Robins, Richard W

    2012-01-01

    This research uses item response theory methods to evaluate the Narcissistic Personality Inventory (NPI; Raskin & Terry, 1988). Analyses using the 2-parameter logistic model were conducted on the total score and the Corry, Merritt, Mrug, and Pamp (2008) and Ackerman et al. (2011) subscales for the NPI. In addition to offering precise information about the psychometric properties of the NPI item pool, these analyses generated insights that can be used to develop new measures of the personality constructs embedded within this frequently used inventory.

  5. The 12 item Social and Economic Conservatism Scale (SECS.

    Directory of Open Access Journals (Sweden)

    Jim A C Everett

    Full Text Available Recent years have seen a surge in psychological research on the relationship between political ideology (particularly conservatism and cognition, affect, behaviour, and even biology. Despite this flurry of investigation, however, there is as yet no accepted, validated, and widely used multi-item scale of conservatism that is concise, that is modern in its conceptualisation, and that includes both social and economic conservatism subscales. In this paper the 12-Item Social and Economic Conservatism Scale (SECS is proposed and validated to help fill this gap. The SECS is suggested to be an important and useful tool for researchers working in political psychology.

  6. Optimization of Design and Planing VHS Building Using Chronolux

    Directory of Open Access Journals (Sweden)

    Beta Paramita

    2016-09-01

    Full Text Available Gedebage integrated vocational high school (SMK is a school which accommodates the concept of technopolis. The school has four programs: building engineering, family welfare education (PKK/food service, mechanical engineering, and tourism - which produce skilled and ready-to-work graduates. This article aims to recommend the sun exposure toward the building of the school, which is related to site planning and design strategies based on the duration of solar radiation on vegetation, and building facades as well as the distance between buildings through the use of Chronolux plug-in on Sketch-up Software. From the measurement, it is found that vegetation can reduce sky view factors (SVF from 76.4 to 38.87%. For the building façade, it is able to reduce sun exposure from 4 hours 51 minutes to 3 hours 19 minutes with SVF from 47.26 to 38.11%. Meanwhile, the building distance of 9 m receives sun exposure from 9:00 am to 3.42 pm.

  7. Neutralisation and binding of VHS virus by monovalent antibody fragments

    DEFF Research Database (Denmark)

    Cupit, P.M.; Lorenzen, Niels; Strachan, G.

    2001-01-01

    We have previously reported the cloning and characterisation of the heavy and light chain variable domain genes encoding three monoclonal antibodies (Mabs) that bind viral haemorrhagic septicaemia virus (VHSV). Two of these antibodies, 3F1H10 and 3F1A2 both neutralised the virus though 3F1A2...... appeared to recognise a broader range of virus isolates. The variable domains of these two antibodies differ by only four residues (Lorenzen et al., 2000a. Fish Shellfish Immunol. 10, 129-142). To further study the mechanism of neutralisation, Fab fragments as well as a series of recombinant bacterial...... by BIAcore analysis and found to correlate with the capacity of each molecule to neutralise DK-F1. These investigations, together with computer assisted molecular analysis of the theoretical influence of each mutation on antigen binding, led to the identification of a single mutation at position 35a...

  8. Optimization of Design and Planing VHS Building Using Chronolux

    OpenAIRE

    Beta Paramita; Ismahnida Kamilia; Muhammad Iqbal Nurhidayat; Resty Ocktaviyane

    2016-01-01

    Gedebage integrated vocational high school (SMK) is a school which accommodates the concept of technopolis. The school has four programs: building engineering, family welfare education (PKK/food service), mechanical engineering, and tourism - which produce skilled and ready-to-work graduates. This article aims to recommend the sun exposure toward the building of the school, which is related to site planning and design strategies based on the duration of solar radiation on vegetation, and buil...

  9. Advanced number theory

    CERN Document Server

    Cohn, Harvey

    1980-01-01

    ""A very stimulating book ... in a class by itself."" - American Mathematical MonthlyAdvanced students, mathematicians and number theorists will welcome this stimulating treatment of advanced number theory, which approaches the complex topic of algebraic number theory from a historical standpoint, taking pains to show the reader how concepts, definitions and theories have evolved during the last two centuries. Moreover, the book abounds with numerical examples and more concrete, specific theorems than are found in most contemporary treatments of the subject.The book is divided into three parts

  10. Elementary theory of numbers

    CERN Document Server

    Sierpinski, Waclaw

    1988-01-01

    Since the publication of the first edition of this work, considerable progress has been made in many of the questions examined. This edition has been updated and enlarged, and the bibliography has been revised.The variety of topics covered here includes divisibility, diophantine equations, prime numbers (especially Mersenne and Fermat primes), the basic arithmetic functions, congruences, the quadratic reciprocity law, expansion of real numbers into decimal fractions, decomposition of integers into sums of powers, some other problems of the additive theory of numbers and the theory of Gaussian

  11. Elementary number theory

    CERN Document Server

    Dudley, Underwood

    2008-01-01

    Ideal for a first course in number theory, this lively, engaging text requires only a familiarity with elementary algebra and the properties of real numbers. Author Underwood Dudley, who has written a series of popular mathematics books, maintains that the best way to learn mathematics is by solving problems. In keeping with this philosophy, the text includes nearly 1,000 exercises and problems-some computational and some classical, many original, and some with complete solutions. The opening chapters offer sound explanations of the basics of elementary number theory and develop the fundamenta

  12. The emergence of number

    CERN Document Server

    Crossley, John N

    1987-01-01

    This book presents detailed studies of the development of three kinds of number. In the first part the development of the natural numbers from Stone-Age times right up to the present day is examined not only from the point of view of pure history but also taking into account archaeological, anthropological and linguistic evidence. The dramatic change caused by the introduction of logical theories of number in the 19th century is also treated and this part ends with a non-technical account of the very latest developments in the area of Gödel's theorem. The second part is concerned with the deve

  13. Numbers and computers

    CERN Document Server

    Kneusel, Ronald T

    2015-01-01

    This is a book about numbers and how those numbers are represented in and operated on by computers. It is crucial that developers understand this area because the numerical operations allowed by computers, and the limitations of those operations, especially in the area of floating point math, affect virtually everything people try to do with computers. This book aims to fill this gap by exploring, in sufficient but not overwhelming detail, just what it is that computers do with numbers. Divided into two parts, the first deals with standard representations of integers and floating point numb

  14. Supersymmetric Displaced Number States

    Directory of Open Access Journals (Sweden)

    Fredy R. Zypman

    2015-06-01

    Full Text Available We introduce, generate and study a family of supersymmetric displaced number states (SDNS that can be considered generalized coherent states of the supersymmetric harmonic oscillator. The family is created from the seminal supersymmetric boson-fermion entangling annihilation operator introduced by Aragone and Zypman and later expanded by Kornbluth and Zypman. Using the momentum representation, the states are obtained analytically in compact form as displaced supersymmetric number states. We study their position-momentum uncertainties, and their bunchiness by classifying them according to their Mandel Q-parameter in phase space. We were also able to find closed form analytical representations in the space and number basis.

  15. Algebraic number theory

    CERN Document Server

    Weiss, Edwin

    1998-01-01

    Careful organization and clear, detailed proofs characterize this methodical, self-contained exposition of basic results of classical algebraic number theory from a relatively modem point of view. This volume presents most of the number-theoretic prerequisites for a study of either class field theory (as formulated by Artin and Tate) or the contemporary treatment of analytical questions (as found, for example, in Tate's thesis).Although concerned exclusively with algebraic number fields, this treatment features axiomatic formulations with a considerable range of applications. Modem abstract te

  16. Fundamentals of number theory

    CERN Document Server

    LeVeque, William J

    1996-01-01

    This excellent textbook introduces the basics of number theory, incorporating the language of abstract algebra. A knowledge of such algebraic concepts as group, ring, field, and domain is not assumed, however; all terms are defined and examples are given - making the book self-contained in this respect.The author begins with an introductory chapter on number theory and its early history. Subsequent chapters deal with unique factorization and the GCD, quadratic residues, number-theoretic functions and the distribution of primes, sums of squares, quadratic equations and quadratic fields, diopha

  17. Brief history of numbers

    CERN Document Server

    Corry, Leo

    2015-01-01

    The world around us is saturated with numbers. They are a fundamental pillar of our modern society, and accepted and used with hardly a second thought. But how did this state of affairs come to be? In this book, Leo Corry tells the story behind the idea of number from the early days of the Pythagoreans, up until the turn of the twentieth century. He presents an overview of how numbers were handled and conceived in classical Greek mathematics, in the mathematics of Islam, in European mathematics of the middle ages and the Renaissance, during the scientific revolution, all the way through to the

  18. Graph pegging numbers

    OpenAIRE

    Helleloid, Geir; Khalid, Madeeha; Moulton, David Petrie; Wood, Philip Matchett

    2008-01-01

    In graph pegging, we view each vertex of a graph as a hole into which a peg can be placed, with checker-like ``pegging moves'' allowed. Motivated by well-studied questions in graph pebbling, we introduce two pegging quantities. The pegging number (respectively, the optimal pegging number) of a graph is the minimum number of pegs such that for every (respectively, some) distribution of that many pegs on the graph, any vertex can be reached by a sequence of pegging moves. We prove several basic...

  19. Professor Stewart's incredible numbers

    CERN Document Server

    Stewart, Ian

    2015-01-01

    Ian Stewart explores the astonishing properties of numbers from 1 to10 to zero and infinity, including one figure that, if you wrote it out, would span the universe. He looks at every kind of number you can think of - real, imaginary, rational, irrational, positive and negative - along with several you might have thought you couldn't think of. He explains the insights of the ancient mathematicians, shows how numbers have evolved through the ages, and reveals the way numerical theory enables everyday life. Under Professor Stewart's guidance you will discover the mathematics of codes,

  20. In competition for the attentional template: can multiple items within visual working memory guide attention?

    Science.gov (United States)

    van Moorselaar, Dirk; Theeuwes, Jan; Olivers, Christian N L

    2014-08-01

    Recent studies have revealed that the deployment of attention can be biased by the content of visual working memory (VWM), but that stored memories do not always interact with attention. This has led to a model which proposes a division within VWM between a single active template that interacts with perception and multiple accessory representations that do not. The present study was designed to study whether multiple memory representations are able to bias attention. Participants performed a visual search task while maintaining a variable number of colors in VWM. Consistent with earlier findings, we observed increased attentional capture by memory related distractors when VWM was filled with a single item. However, memory related capture was no longer present for memory loads beyond a single item. The absence of memory related capture at higher VWM loads was independent of individual VWM capacity, nor was it attributable to weaker encoding, forgetting, or reduced precision of memory representations. When analyses were limited to those trials in which participants had a relatively precise memory, there was still no sign of attentional guidance at higher loads. However, when observers were cued toward a specific memory item after encoding, interference with search returned. These results are consistent with a distinction within VWM between representations that interact with perception and those that do not, and show that only a single VWM representation at a time can interact with visual attention.

  1. Identifying patterns of item missing survey data using latent groups: an observational study

    Science.gov (United States)

    McElwee, Paul; Nathan, Andrea; Burton, Nicola W; Turrell, Gavin

    2017-01-01

    Objectives To examine whether respondents to a survey of health and physical activity and potential determinants could be grouped according to the questions they missed, known as ‘item missing’. Design Observational study of longitudinal data. Setting Residents of Brisbane, Australia. Participants 6901 people aged 40–65 years in 2007. Materials and methods We used a latent class model with a mixture of multinomial distributions and chose the number of classes using the Bayesian information criterion. We used logistic regression to examine if participants’ characteristics were associated with their modal latent class. We used logistic regression to examine whether the amount of item missing in a survey predicted wave missing in the following survey. Results Four per cent of participants missed almost one-fifth of the questions, and this group missed more questions in the middle of the survey. Eighty-three per cent of participants completed almost every question, but had a relatively high missing probability for a question on sleep time, a question which had an inconsistent presentation compared with the rest of the survey. Participants who completed almost every question were generally younger and more educated. Participants who completed more questions were less likely to miss the next longitudinal wave. Conclusions Examining patterns in item missing data has improved our understanding of how missing data were generated and has informed future survey design to help reduce missing data. PMID:29084795

  2. Do animals and furniture items elicit different brain responses in human infants?

    Science.gov (United States)

    Jeschonek, Susanna; Marinovic, Vesna; Hoehl, Stefanie; Elsner, Birgit; Pauen, Sabina

    2010-11-01

    One of the earliest categorical distinctions to be made by preverbal infants is the animate-inanimate distinction. To explore the neural basis for this distinction in 7-8-month-olds, an equal number of animal and furniture pictures was presented in an ERP-paradigm. The total of 118 pictures, all looking different from each other, were presented in a semi-randomized order for 1000ms each. Infants' brain responses to exemplars from both categories differed systematically regarding the negative central component (Nc: 400-600ms) at anterior channels. More specifically, the Nc was enhanced for animals in one subgroup of infants, and for furniture items in another subgroup of infants. Explorative analyses related to categorical priming further revealed category-specific differences in brain responses in the late time window (650-1550ms) at right frontal channels: Unprimed stimuli (preceded by a different-category item) elicited a more positive response as compared to primed stimuli (preceded by a same-category item). In sum, these findings suggest that the infant's brain discriminates exemplars from both global domains. Given the design of our task, we conclude that processes of category identification are more likely to account for our findings than processes of on-line category formation during the experimental session. Copyright © 2009 Elsevier B.V. All rights reserved.

  3. Multiple sensitive estimation and optimal sample size allocation in the item sum technique.

    Science.gov (United States)

    Perri, Pier Francesco; Rueda García, María Del Mar; Cobo Rodríguez, Beatriz

    2017-09-27

    For surveys of sensitive issues in life sciences, statistical procedures can be used to reduce nonresponse and social desirability response bias. Both of these phenomena provoke nonsampling errors that are difficult to deal with and can seriously flaw the validity of the analyses. The item sum technique (IST) is a very recent indirect questioning method derived from the item count technique that seeks to procure more reliable responses on quantitative items than direct questioning while preserving respondents' anonymity. This article addresses two important questions concerning the IST: (i) its implementation when two or more sensitive variables are investigated and efficient estimates of their unknown population means are required; (ii) the determination of the optimal sample size to achieve minimum variance estimates. These aspects are of great relevance for survey practitioners engaged in sensitive research and, to the best of our knowledge, were not studied so far. In this article, theoretical results for multiple estimation and optimal allocation are obtained under a generic sampling design and then particularized to simple random sampling and stratified sampling designs. Theoretical considerations are integrated with a number of simulation studies based on data from two real surveys and conducted to ascertain the efficiency gain derived from optimal allocation in different situations. One of the surveys concerns cannabis consumption among university students. Our findings highlight some methodological advances that can be obtained in life sciences IST surveys when optimal allocation is achieved. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Detection of Abnormal Item Based on Time Intervals for Recommender Systems

    Directory of Open Access Journals (Sweden)

    Min Gao

    2014-01-01

    Full Text Available With the rapid development of e-business, personalized recommendation has become core competence for enterprises to gain profits and improve customer satisfaction. Although collaborative filtering is the most successful approach for building a recommender system, it suffers from “shilling” attacks. In recent years, the research on shilling attacks has been greatly improved. However, the approaches suffer from serious problem in attack model dependency and high computational cost. To solve the problem, an approach for the detection of abnormal item is proposed in this paper. In the paper, two common features of all attack models are analyzed at first. A revised bottom-up discretized approach is then proposed based on time intervals and the features for the detection. The distributions of ratings in different time intervals are compared to detect anomaly based on the calculation of chi square distribution (χ2. We evaluated our approach on four types of items which are defined according to the life cycles of these items. The experimental results show that the proposed approach achieves a high detection rate with low computational cost when the number of attack profiles is more than 15. It improves the efficiency in shilling attacks detection by narrowing down the suspicious users.

  5. Detection of abnormal item based on time intervals for recommender systems.

    Science.gov (United States)

    Gao, Min; Yuan, Quan; Ling, Bin; Xiong, Qingyu

    2014-01-01

    With the rapid development of e-business, personalized recommendation has become core competence for enterprises to gain profits and improve customer satisfaction. Although collaborative filtering is the most successful approach for building a recommender system, it suffers from "shilling" attacks. In recent years, the research on shilling attacks has been greatly improved. However, the approaches suffer from serious problem in attack model dependency and high computational cost. To solve the problem, an approach for the detection of abnormal item is proposed in this paper. In the paper, two common features of all attack models are analyzed at first. A revised bottom-up discretized approach is then proposed based on time intervals and the features for the detection. The distributions of ratings in different time intervals are compared to detect anomaly based on the calculation of chi square distribution (χ(2)). We evaluated our approach on four types of items which are defined according to the life cycles of these items. The experimental results show that the proposed approach achieves a high detection rate with low computational cost when the number of attack profiles is more than 15. It improves the efficiency in shilling attacks detection by narrowing down the suspicious users.

  6. By the book: ADHD prevalence in medical students varies with analogous methods of addressing DSM items.

    Science.gov (United States)

    Mattos, Paulo; Nazar, Bruno P; Tannock, Rosemary

    2018-02-15

    The marked increase in the prevalence of attention-deficit/hyperactivity disorder (ADHD) among university students gives rise to questions about how best to diagnose in this setting. The aim of the present study was to calculate ADHD prevalence in a large non-clinical sample of medical students using a stepwise design and to determine whether ADHD diagnosis varies if interviewees use additional probing procedures to obtain examples of positive DSM items. A total of 726 students were screened with the Adult Self-Report Scale (ASRS) and invited for an interview with the Kiddie Schedule for Affective Disorders and Schizophrenia (K-SADS) adapted for adults. The ASRS was positive for 247 students (37%), although only 83 (7.9%) received an ADHD diagnosis. ASRS sensitivity and specificity rates were 0.97 and 0.40, respectively. Probing procedures were used with a subgroup of 226 students, which decreased the number of ADHD diagnoses to 12 (4.5%). Probing for an individual's real-life examples during the K-SADS interview almost halved ADHD prevalence rate based on the ASRS and K-SADS, which rendered the rate consistent with that typically reported for young adults. In reclassified cases, although examples of inattention did not match the corresponding DSM item, they often referred to another DSM inattention item.

  7. Vendor managed inventory control system for deteriorating items using metaheuristic algorithms

    Directory of Open Access Journals (Sweden)

    Masoud Rabbani

    2018-01-01

    Full Text Available Inventory control of deteriorating items constitutes a large part of the world’s economy and covers various goods including any commodity, which loses its worth over time because of deterioration and/or obsolescence. Vendor managed inventory (VMI, which is a win-win strategy for both suppliers and buyers gains better results than traditional supply chain. In this research, we study an economic order quantity (EOQ with shortage in form of partial backorder under VMI policy. The model is concerned with multi-item subject to multi-constraint including storage space, time period and budget constraints. Two metaheuristic algorithms, namely Simulated Annealing and Tabu Search, are used to find a near optimal solution for the proposed fuzzy nonlinear integer-programming problem with the objective of minimizing the total cost of the supply chain. Furthermore, the sensitivity analysis of the metaheuristic parameters is performed and five numerical examples containing different numbers of items are conducted in order to evaluate the performance of the algorithms.

  8. Really big numbers

    CERN Document Server

    Schwartz, Richard Evan

    2014-01-01

    In the American Mathematical Society's first-ever book for kids (and kids at heart), mathematician and author Richard Evan Schwartz leads math lovers of all ages on an innovative and strikingly illustrated journey through the infinite number system. By means of engaging, imaginative visuals and endearing narration, Schwartz manages the monumental task of presenting the complex concept of Big Numbers in fresh and relatable ways. The book begins with small, easily observable numbers before building up to truly gigantic ones, like a nonillion, a tredecillion, a googol, and even ones too huge for names! Any person, regardless of age, can benefit from reading this book. Readers will find themselves returning to its pages for a very long time, perpetually learning from and growing with the narrative as their knowledge deepens. Really Big Numbers is a wonderful enrichment for any math education program and is enthusiastically recommended to every teacher, parent and grandparent, student, child, or other individual i...

  9. Quantum random number generators

    Science.gov (United States)

    Herrero-Collantes, Miguel; Garcia-Escartin, Juan Carlos

    2017-01-01

    Random numbers are a fundamental resource in science and engineering with important applications in simulation and cryptography. The inherent randomness at the core of quantum mechanics makes quantum systems a perfect source of entropy. Quantum random number generation is one of the most mature quantum technologies with many alternative generation methods. This review discusses the different technologies in quantum random number generation from the early devices based on radioactive decay to the multiple ways to use the quantum states of light to gather entropy from a quantum origin. Randomness extraction and amplification and the notable possibility of generating trusted random numbers even with untrusted hardware using device-independent generation protocols are also discussed.

  10. Solar Indices - Sunspot Numbers

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  11. Drawing a random number

    DEFF Research Database (Denmark)

    Wanscher, Jørgen Bundgaard; Sørensen, Majken Vildrik

    2006-01-01

    highly uniform multidimensional draws, which are highly relevant for todays traffic models. This paper shows among others combined shuffling and scrambling seems needless, that scrambling gives the lowest correlation and that there are detectable differences between random numbers, dependent...

  12. LLWnotes - Volume 11, Number 4

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-05-01

    This document is the May 1996 issue of LLWnotes. It contains articles and news items on the following topics: news items related to states and compacts; Low-Level Radioactive Waste (LLW) Forum activities; court rulings and calendars; US DOE testing at Ward Valley; US BLM contract with Lawrence Livermore National Laboratory; Mixed Waste Pilot Project Schedule; extension of US EPA`s mixed waste enforcement moratorium; EPA Advisory Committee on research program operation; and decommissioning.

  13. Development and Validation of a Novel Generic Health-related Quality of Life Instrument With 20 Items (HINT-20

    Directory of Open Access Journals (Sweden)

    Min-Woo Jo

    2017-01-01

    Full Text Available Objectives Few attempts have been made to develop a generic health-related quality of life (HRQoL instrument and to examine its validity and reliability in Korea. We aimed to do this in our present study. Methods After a literature review of existing generic HRQoL instruments, a focus group discussion, in-depth interviews, and expert consultations, we selected 30 tentative items for a new HRQoL measure. These items were evaluated by assessing their ceiling effects, difficulty, and redundancy in the first survey. To validate the HRQoL instrument that was developed, known-groups validity and convergent/discriminant validity were evaluated and its test-retest reliability was examined in the second survey. Results Of the 30 items originally assessed for the HRQoL instrument, four were excluded due to high ceiling effects and six were removed due to redundancy. We ultimately developed a HRQoL instrument with a reduced number of 20 items, known as the Health-related Quality of Life Instrument with 20 items (HINT-20, incorporating physical, mental, social, and positive health dimensions. The results of the HINT-20 for known-groups validity were poorer in women, the elderly, and those with a low income. For convergent/discriminant validity, the correlation coefficients of items (except vitality in the physical health dimension with the physical component summary of the Short Form 36 version 2 (SF-36v2 were generally higher than the correlations of those items with the mental component summary of the SF-36v2, and vice versa. Regarding test-retest reliability, the intraclass correlation coefficient of the total HINT-20 score was 0.813 (p<0.001. Conclusions A novel generic HRQoL instrument, the HINT-20, was developed for the Korean general population and showed acceptable validity and reliability.

  14. A Simulated Single-Item Aggregate Inventory Model for U.S. Navy Repairable Items

    Science.gov (United States)

    1993-09-01

    condition, or a procurement order is received. The model also introduced two new variables, SAFTY and COUN"[1]. Both were used in the events where INV...changed as a result of these types of receipts (i.e., in the events SHIPI and RCVD2). In each event, SAFTY summed the value of net inventory; i.e... SAFTY - SAFTY + INV, while COUNT [1] accumulated the total number of times net inventory increased. When 850 quarters was reached, the event STATS

  15. Persistent consequences of atypical early number concepts

    Directory of Open Access Journals (Sweden)

    Michèle M. M. Mazzocco

    2013-09-01

    Full Text Available How does symbolic number knowledge performance help identify young children at risk for poor mathematics achievement outcomes? In research and practice, classification of mathematics learning disability (MLD, or dyscalculia is typically based on composite scores from broad measures of mathematics achievement. These scores do predict later math achievement levels, but do not specify the nature of math difficulties likely to emerge among students at greatest risk for long-term mathematics failure. Here we report that gaps in 2nd and 3rd graders’ number knowledge predict specific types of errors made on math assessments at Grade 8. Specifically, we show that early whole number misconceptions predict slower and less accurate performance, and atypical computational errors, on Grade 8 arithmetic tests. We demonstrate that basic number misconceptions can be detected by idiosyncratic responses to number knowledge items, and that when such misconceptions are evident during primary school they persist throughout the school age years, with variable manifestation throughout development. We conclude that including specific qualitative assessments of symbolic number knowledge in primary school may provide greater specificity of the types of difficulties likely to emerge among students at risk for poor mathematics outcomes.

  16. Prevalence and correlates of abuse screening items among community-dwelling Hong Kong Chinese older adults.

    Science.gov (United States)

    Leung, Doris Yp; Lo, Shirley Kl; Leung, Angela Ym; Lou, Vivian Wq; Chong, Alice Ml; Kwan, Joseph Sk; Chan, Wallace Ch; Chi, Iris

    2017-01-01

    The present study aims to describe the prevalence of potential elder abuse, and to examine correlates of abuse screening items among Chinese community-dwelling older adults. We analyzed the data of 3435 older persons aged ≥60 years who had first applied for the long-term care services in Hong Kong and completed the screening tool (Minimum Data Set-Home Care) in 2006. For each of the five abuse screening items ("fearful of a family member/caregiver," "unexplained injuries/broken bones/burns," "physically restrained," "unusually poor hygiene" and "neglected/abused/mistreated"), we examined its relationship with four types of factors: older person, perpetrator, relationship and environment. The rates of individual abuse screening items ranged from 3.9% for physically restrained to 0.03% for unexplained injures/broken bones/burns. Physically restrained was positively associated with activities of daily living impairments, instrumental activities of daily living impairments, perceived poor health, physically abusive behavior and caregiver mental health. Unusually poor hygiene was positively associated with socially inappropriate behavior and actively resisted care. "Fearful of a family member/caregiver" was positively associated with perceived poor health, conflicting relationship and mental health, and negatively with care activities. Neglected/abused/mistreated was positively associated with age and informal care, and negatively with care activities. We identified a number of associated factors of different abuse screening items among older adults. Our findings could inform healthcare practitioners in identifying those older persons who might be at higher risk of abuse, and provide a knowledge base on which to develop effective preventive measures in the Chinese population. Geriatr Gerontol Int 2017; 17: 150-160. © 2015 Japan Geriatrics Society.

  17. Assessment of dietary fish consumption in pregnancy: comparing 1, 4, and 36 item questionnaires

    Science.gov (United States)

    Oken, Emily; Guthrie, Lauren B.; Bloomingdale, Arienne; Gillman, Matthew W.; Olsen, Sjurdur F.; Amarasiriwardena, Chitra J.; Platek, Deborah N.; Bellinger, David C.; Wright, Robert O.

    2014-01-01

    Objective Fish consumption influences a number of health outcomes. Few studies have directly compared dietary assessment methods to determine the best approach to estimating intake of fish and its component nutrients, including docosahexaenoic acid (DHA), and toxicants, including methylmercury. Our objective was to compare 3 methods of assessing fish intake. Design We assessed 30-day fish intake using 3 approaches: a single question on total fish consumption, a brief comprehensive food frequency questionnaire (FFQ) that included 4 questions about fish, and a focused FFQ with 36 questions about different finfish and shellfish. Setting Obstetrics practices in Boston, MA Subjects 59 pregnant women who consumed mercury were lowest with the 1-question screener, and highest with the 36-item fish questionnaire. Estimated intake of DHA with the 36-item questionnaire was 4.4 fold higher (97 vs. 22 mg/day), and intake of mercury was 3.8-fold higher (1.6 vs. 0.42 mcg/day), compared with the 1-question screener. Plasma DHA concentration was correlated with fish intake assessed with the 1-question screener (Spearman r=0.27, p=0.04), but not with the 4-item FFQ (r=0.08, p=0.54) or 36-item fish questionnaire (r=0.01, p=0.93). In contrast, blood and hair mercury concentrations were similarly correlated with fish and mercury intake regardless of the assessment method (r= 0.35 to 0.52). Conclusions A longer questionnaire provides no advantage over shorter questionnaires in ranking intake of fish, DHA, and mercury compared with biomarkers, but estimates of absolute intakes can vary by as much as 4-fold across methods. PMID:23883550

  18. Rich Food Biodiversity Amid Low Consumption of Food Items in Kilosa District, Tanzania.

    Science.gov (United States)

    Ntwenya, Julius E; Kinabo, Joyce; Msuya, John; Mamiro, Peter; Mamiro, Delphina; Njoghomi, Elifuraha; Liwei, Philip; Huang, Megan

    2017-12-01

    Indigenous foods, which contribute largely to the majority of the households' food basket in rural Tanzanian communities, have not been fully characterized or documented. The study aimed to document foods available and consumed in Kilosa District, Tanzania, in an attempt to promote, revive use, and build evidence for sustainable utilization of the rich local biodiversity. Data were collected from 307 households in 3 agroecological zones in Kilosa District during the beginning of the rainy season (February-May) and immediately after harvest (September-October). A list of food items was generated, and 24-hour recall was performed. Descriptive statistics were calculated and a student t test statistic was used to compare the means of the Food Biodiversity Score between the agricultural seasons. A total of 183 edible food items were reported by households with more reported in the rainy season (n = 82) compared to harvest season (n = 64). The mean number of food items consumed per day during the rainy season was 4.7 (95% CI: 4.5-5.0) compared to 5.9 (95% CI: 5.7-6.1) during harvest season. About 50% of the households mentioned that wild edible foods were less accepted by household members. Despite the rich local food biodiversity, households relied on few food items which may be due to limited awareness and knowledge about the biodiversity of foods in the community. It is important to educate communities on the rich and affordable food base available locally to improve their food diversity, income, and nutritional status.

  19. [Measuring workplace climate: reliability and validity of the 12-item Organizational Climate Scale (OCS-12)].

    Science.gov (United States)

    Fukui, Satoe; Haratani, Takashi; Toshima, Yutaka; Shima, Satoru; Takahashi, Masaya; Nakata, Akinori; Fukasawa, Kenji; Ohba, Sayo; Sato, Emi; Hirota, Yasuko

    2004-11-01

    In order to investigate the reliability and validity of the short version of the 30-item Organizational Climate Scale (OCS-30; Toshima and Matsuda, 1992, 1995), a self-administered questionnaire was conducted in a sample of 819 employees of two medium-sized private companies in Japan by using the OCS-30, the Generic Job Stress Questionnaire (GJSQ), and the 12-item General Health Questionnaire (GHQ-12). The OCS has two subscales, i.e., the Tradition Scale (TS) and the Organizational Environment Scale (OES). The organizational climate perceived by each worker can be grouped into four categories based on the subscale scores: low TS and high OES (Active), high TS and high OES (Governed), low TS and low OES (Disorganized), and high TS and low OES (Reluctant). Principal component analysis for the OCS-30 was submitted (varimax rotation, the number of factors = 2), and 6 items for each factor, with factor loadings greater than 0.50, were selected for the short version, which constituted the 12-item Organizational Climate Scale (OCS-12). Cronbach's alpha reliability coefficients of the two subscales of the OCS-12 were acceptable; 0.63 for the TS and 0.71 for the OES. Both two subscales of the OCS-12 were significantly correlated with the GHQ-12 and many subscales of the GJSQ, which indicated the good constructive validity of the OCS-12. Among 4 types of organizational climate categorized by the OCS-12, the "Active" group showed the lowest job stress scores. It is suggested that the OCS-12 could be a reliable and valid instrument for assessing workers' perception of workplace climate.

  20. Prediction of true test scores from observed item scores and ancillary data.

    Science.gov (United States)

    Haberman, Shelby J; Yao, Lili; Sinharay, Sandip

    2015-05-01

    In many educational tests which involve constructed responses, a traditional test score is obtained by adding together item scores obtained through holistic scoring by trained human raters. For example, this practice was used until 2008 in the case of GRE(®) General Analytical Writing and until 2009 in the case of TOEFL(®) iBT Writing. With use of natural language processing, it is possible to obtain additional information concerning item responses from computer programs such as e-rater(®). In addition, available information relevant to examinee performance may include scores on related tests. We suggest application of standard results from classical test theory to the available data to obtain best linear predictors of true traditional test scores. In performing such analysis, we require estimation of variances and covariances of measurement errors, a task which can be quite difficult in the case of tests with limited numbers of items and with multiple measurements per item. As a consequence, a new estimation method is suggested based on samples of examinees who have taken an assessment more than once. Such samples are typically not random samples of the general population of examinees, so that we apply statistical adjustment methods to obtain the needed estimated variances and covariances of measurement errors. To examine practical implications of the suggested methods of analysis, applications are made to GRE General Analytical Writing and TOEFL iBT Writing. Results obtained indicate that substantial improvements are possible both in terms of reliability of scoring and in terms of assessment reliability. © 2015 The British Psychological Society.