Similarity solutions of partial differential equations using DESOLV

We present and describe new reduction routines included in DESOLV which, in many cases, may allow the complete automation of the determination of similarity solutions of partial differential equations.

Feasibility study of partial recrystallisation in multi-pass hot deformation process and application to calculation of mean flow stress

A feasibility study for handling the partial recrystallisation in multi-pass hot deformation where the heterogeneity of microstructure of deformed austenite is inherently accompanied is presented. The proposed model is based on modification of the conventional model in which the microstructure of deformed austenite at each pass is simply taken as being homogeneous during the multi-pass deformation. The usefulness of the modified model has been demonstrated by applying it to a four-pass oval–round (or round–oval) rod rolling sequence. The recrystallised fraction, austenite grain size (AGS) and mean flow stress at each pass computed from the modified model has been compared with those from the conventional model. The result showed that the recrystallisation behaviour and evolution of AGS at a given pass were dependent on the modelling method of the partial recrystallisation in the multi-pass rolling for the case studied. As the rolling speed increased, the difference between the mean flow stresses calculated by the conventional model and the proposed model was gradually larger in accordance with the contribution of partial recrystallisation.

Meeting the Standards: An Analysis of Eight Grade Educational Assesment Test Scores in Maine

This paper examines the impact of socioeconomic factors on eighth grade achievement test scores in the face of federal and state initiatives for educational reform in Maine. We use student-level data over a five year period to provide a framework for understanding the policy implications of these initiatives. We model performance on standardized tests using a seemingly unrelated regressions approach and then determine the likelihood of meeting the standards defined by the adequate yearly progress requirements of the No Child Left Behind Act and Maine Learning Results initiatives. Our results indicate that the key factors influencing a student’s test scores include the education of a student’s parents, special services received for learning disabilities, and alternative measures of academic achievement.

Two stage partial classification for inconsistent and imbalanced classes

When deriving classification rules for a non-symmetric database with a binary target class, it is common practice to generate rules for the majority class, then any object which is not covered by a rule of suitable accuracy is by default given the minority class prediction. However, in the case where misclassification costs for the minority class significantly outweigh those of the majority class, this may mean that there are still costly incorrect predictions. We examine the capability of an evolutionary algorithm to detect these potentially costly misclassifications.

Socially optimal criminal court waiting times : a partial investigation

Criminal courts provide a forum for conducting prosecutions with a guilty plea or a trial. Since queues are used as the basis for rationing scarce court facilities delays are inevitable, however courts are invariably criticised as being inefficient as a consequence. This focus on court delay defined as the time elapsing between the listing of the case in the court list and its final disposition is misleading. Rather, attention should be drawn to the considerably longer period between the initiation of proceedings and the conclusion of the case. In the case of defendants not granted bail, this pre-trial delay confers both costs and benefits on society and this observation can be used to ascertain socially optimal pre-trial waits.

Partial purification and characterization of limonoate dehydrogenase from Rhodococcus fascians for the degradation of limonin

An extracellular limonoate dehydrogenase was purified 10-fold from a cell-free extract of Rhodococcus fascians by ammonium sulfate precipitation, dialysis, and ultrafiltration. This purified dehydrogenase catalyzed the
conversion of limonoate to 17-dehydrolimonoate. The enzyme showed optimum activity at pH 8.0 and 40oC, with K_m value of 0.9 µM, and requires Zn ions and sulfhydryl groups for catalytic action. The enzyme activity was inhibited by Hg²⁺ and NaN₃ ions. The degradation of limonin (66%) in Kinnow mandarin juice was successfully demonstrated with partially
purified limonoate dehydrogenase. With scale-up preparation of limonoate dehydrogenase, a successful debittering operation of fruit juices appears feasible.

Partial purification and characterization of exoinulinase from kluyveromyces marxianus YS-1 for preparation of high-fructose syrup

An extracellular exoinulinase( ^{2, 1}- ß- D fructan fructanohydrolase, EC 3.2.1.7), which catalyzes the hydrolysis of inulin into fructose and glucose, was purified 23.5-fold by ethanol precipitation, followed by Sephadex G-100 gel permeation from a cell-free extract of Kluyveromyces marxianus YS-1. The partially purified enzyme exhibited considerable activity between pH 5 to 6, with an optimum pH of 5.5, while it remained stable(100%) for 3 h at the optimum temperature of 50º c. Mn²⁺ and Ca²⁺ produced a 2A-fold and 1.2-fold enhancement in enzyme activity, whereas Hg²⁺ and Ag²⁺  completely inhibited the inulinase. A preparation of the partially purified enzyme effectively hydrolyzed inulin, sucrose, and raffinose, yet no activity was found with starch, lactose, and maltose. The enzyme preparation was then successfully used to hydrolyze pure inulin and raw inulin from Asparagus racemosus for the preparation of a high-fructose syrup. In a batch system, the exoinulinase hydrolyzed 84.8% of the pure inulin and 86.7% of the raw Asparagus racemosus inulin, where fructose represented 43.6mg/ml and 41.3mg/ml, respectively.

Absolute versus relative difference measures of priming: Which is appropriate when baseline scores change with age?

It is often of theoretical interest to know if implicit memory (repetition priming) develops across childhood under a given circumstance. Methodologically, however, it is difficult to determine whether development is present when baseline performance for unstudied items improves with age. Calculation of priming in absolute (priming=studied - unstudied) or relative-to-baseline terms can lead to different conclusions. In first noting this problem, Parkin (1993) suggested using the Snodgrass (1989a) calculation of relative priming [priming=(studied - unstudied)/(maximum - unstudied)], and most developmental studies have since adopted this procedure. Here, we question the Snodgrass method because the Snodgrass method's results are not replicated in the picture identification task when baselines are equated experimentally across age groups. Instead, results support an absolute measure of priming. Theoretically, we argue against its core assumption; namely, that children and adults always lie on the same learning curve, with an equal maximum performance level and equal rate of learning.

Mathematical power of special-needs pupils : an ICT-based dynamic assessment format to reveal weak pupils' learning potential

This paper reports a study aimed at revealing special-educational-needs pupils' learning potential by means of an ICT-based assessment including a dynamic visual tool that might help pupils when solving mathematics problems. The study focused on subtraction problems up to 100, which require 'borrowing'. These problems, in which the value of the ones-digit of the subtrahend is larger than the ones-digit of the minuend, are known as a serious difficulty for weak pupils in mathematics. Seven of such problems from a standardised test were placed in the ICT environment. Data were collected from two test conditions: the standardised written test format and the ICT version of the test items including the tool that provided pupils with a set of virtual manipulatives. The 37 pupils involved in the study were 8–12 years old and from two special-education schools in the Netherlands. Comparison of the performance scores in the two formats showed that an ICT-based assessment format, including a dynamic visual tool, can reveal weak pupils' learning potential and strategy use. The study also pointed out that 'partial-tool use', ie, not carrying out the complete subtraction operation with the tool, can provide sufficient support to find the correct answer.

Should partial least squares be used for analysing psychological constructs?

This paper critically examines an analytical tool - partial least squares regression, or P LS - that is increasingly being used in the academic business literature to validate measures of psychological constructs, and to test hypotheses based on these. The paper provides a contextual and historical review of the resurgence of P LS, and explores several of the claims made by its developers and supporters when it was first promoted in the 1980s, and, more recently, when it reappeared in the information systems literature. Many claims appear plausible but rest on non-mainstream uses of terms and concepts taken from the psychometric field. The paper also canvasses why P LS is a poor analytical tool for research that involves psychological constructs.

Lie symmetries of partial differential equations using symbolic computing

This study presents a theoretical basis for and outlines the method of finding the Lie point symmetries of systems of partial differential equations. It seeks to determine which of five computer algebra packages is best at finding these symmetries. The chosen packages are LIEPDE and DIMSYM for REDUCE, LIE and BIGLIE for MUMATH, DESOLV for MAPLE, and MATHLIE for MATHEMATICA. This work concludes that while all of the computer packages are useful, DESOLV appears to be the most successful system at determining the complete set of Lie symmetries. Also, the study describes REDUCEVAR, a new package for MAPLE, that reduces the number of independent variables in systems of partial differential equations, using particular Lie point symmetries. It outlines the results of some testing carried out on this package. It concludes that REDUCEVAR is a very useful tool in performing the reduction of independent variables according to Lie's theory and is highly accurate in identifying cases where the symmetries are not suitable for finding S/G equations.

Examination of the validity and usefulness of the video suggestibility scale for children

The Video Suggestibility Scale for Children (VSSC) was developed by Scullin and colleagues (Scullin & Ceci, 2000; Scullin & Hembrooke, 1998) as a tool for discriminating between children who have different levels of suggestibility. The scale requires children to view a 5-minute video about a birthday party, and to subsequently participate in an interview consisting of 18 yes/no questions. The VSSC consists of two main subscales; Yield (a measure of children's willingness to respond affirmatively to misleading questions about the video) and Shift (a measure of the children's tendency to change their responses after negative feedback from the interviewer). Preliminary research by Scullin and colleagues suggested that the scale possesses satisfactory internal consistency and that children's scores on the VSSC can predict their performance in another suggestibility paradigm. This thesis presents two studies, which further examine the validity and usefulness of the VSSC in an Australian sample of 3- to-5-year-old children. In Study One, children's performance on the VSSC (N = 77) was compared to their performance using other measures of suggestibility. These measures included children's willingness to assent to a false event as well as the number of false interviewer suggestions and new false details that the children provided in their accounts about an independent true-biased and an independent false (non-experienced) event. An independent samples t-test revealed that those children who assented to the false activity generated higher scores on the Yield measure. This pattern was also observed for the Shift subscale although it was not significant. Hierarchical regression analyses revealed that Yield was a significant predictor of the number of false details reported about the false activity, but not the true-biased activity. There was no significant relationship between the Shift Vlll subscale and any of the dependent variables. Overall this study provided partial support for the construct validity of the VSSC. However, it indicated that children's performance on this scale may not be generalisable across different contexts and interview paradigms, and that the Yield subscale is more generalisable than the Shift subscale. Study Two examined whether various group and individual factors that have previously been shown to relate suggestibility (i.e., age, IQ, memory, socio-economic status, gender, temperament) could predict suggestibility as measured by the VSSC. Two hundred and twenty children were recruited from kindergartens, and were divided into two broad socio-economic categories (based predominantly on income). Hierarchical regression analyses revealed that age, intelligence and memory inversely predicted children's Yield suggestibility. Further, children of low socio-economic backgrounds were more suggestible than children of high socio-economic background, and boys were more suggestible than girls on the Yield measure. Although shyness and other internalised and externalised characteristics were explored, no reliable significant relationships were found with Yield. With regard to the Shift subscale, no reliable relationships were found for any of the independent variables except for SES. Overall, results of Study 2 indicated that the VSSC is a potentially useful measure for discriminating between children's suggestibility on the basis on their individual characteristics, although benefits were observed mainly in relation to the Yield subscale. With reference to the findings of these two studies, the potential contribution of the VSSC for research and applied forensic contexts was discussed.

The effects of phonological and morphological training on speech perception scores and grammatical judgments in deaf and hard-of-hearing children

Seventeen primary school deaf and hard-of-hearing children were given two types of training for 9 weeks each. Phonological training involved practice of /s, z, t, d/ in word final position in monomorphemic words. Morphological training involved learning and practicing the rules for forming third-person singular, present tense, past tense, and plurals. The words used in the two training types were different (monomorphemic or polymorphemic) but both involved word final /s, z, t, d/. Grammatical judgments were tested before and after training using short sentences that were read aloud by the child (or by the presenter if the child was unable to read them). Perception was tested with 150 key words in sentences using the trained morphemes and phonemes in word final position. Grammatical judgments for sentences involving the trained morphemes improved significantly after each type of training. Both types of training needed to be completed before a significant improvement was found for speech perception scores. The results suggest that both phonological and morphological training are beneficial in improving speech perception and grammatical performance of deaf and hard-of-hearing children and that both types of training were required to obtain the maximum benefit.

Separating the contributions of hearing, lexical knowledge and speech production to speech perception scores in children with hearing impairments.

Open-set word and sentence speech-perception test scores are commonly used as a measure of hearing abilities in children and adults using cochlear implants and/or hearing aids. These tests are usually presented auditorily with a verbal response. In the case of children, scores are typically lower and more variable than for adults with hearing impairments using similar devices. It is difficult to interpret children's speech-perception scores without considering the effects of lexical knowledge and speech-production abilities on their responses. This study postulated a simple mathematical model to describe the effects of hearing, lexical knowledge, and speech production on the perception test scores for monosyllabic words by children with impaired hearing. Thirty-three primary-school children with impaired hearing, fitted with hearing aids and/or cochlear implants, were evaluated using speech-perception, reading-aloud, speech-production, and language measures. These various measures were incorporated in the mathematical model, which revealed that performance in an open-set word-perception test in the auditory-alone mode is strongly dependent on residual hearing levels, lexical knowledge, and speech-production abilities. Further applications of the model provided an estimate of the effect of each component on the overall speech-perception score for each child.