Linearity of an Electrophotographic Image Reproduction System

The linearity of image transfer is analyzed for a high resolution electrophotographic film and electrodeveloper combination. The extent of nonlinearities introduced upon transfer through the photoconduction and electrodevelopment stages is conceptualized in terms of inherent physical mechanisms. A spectral shift in narrow band exposing radiation is used to test significance of exponential absorption on linearity of photoconduction transfer. Variations in development electrode spacing and development time test for nonlinearity induced by temporal and spatial frequency dependent depletion of electrodeveloper particles. As the electrophotographic film employed in the test exhibited low absorption coefficients in all spectral bands, exponential absorption of exposing radiation did not significantly alter linearity of edge image transfer. Results for edge and sinusoidal image transfer indicated nonlinear depletion effects shortly after development initiation. Increased development times reduced adjacency effects for edge distributions and lower harmonic distortions for sinusoidal image distributions. Initial adjacency effects and time rate of change toward linear edge responses are altered by electrode spacing for one electrodevelopment apparatus tested. Reasonable approximations to linear image transfer are obtained as electrodevelopment approaches completion, regardless of electrode spacing or electrodevelopment apparatus employed

Lack of an HSP70 heat shock response in two Antarctic marine invertebrates

Members of the HSP70 gene family comprising the inducible (HSP70) genes and GRP78 (glucose-regulated protein 78 kDa) were identified in an Antarctic sea star (Odontaster validus) and an Antarctic gammarid (Paraceradocus gibber). These genes were surveyed for expression levels via Q-PCR after an acute 2-hour heat shock experiment in both animals and a time course assay in O. validus. No significant up-regulation was detected for any of the genes in either of the animals during the acute heat shock. The time course experiment in O. validus produced slightly different results with an initial down regulation in these genes at 2°C, but no significant up-regulation of the genes either at 2 or 6°C. Therefore, the classical heat shock response is absent in both species. The data is discussed in the context of the organisms’ thermal tolerance and the applicability of HSP70 to monitor thermal stress in Antarctic marine organisms

Academic casual attributions and course performance for college students

The purpose of the study was to compare student perceptions of the role of the teacher with that of ability, effort, and luck in accounting for student successes and failures. An attribution questionnaire addressing attributional style as it relates to success and failure outcomes in a college course was designed for this study. The College Academic Attribution Scale (CAAS) was designed, because previous attributional scales such as the Multidimensional-Multiattributional Causality Scale and the Attributional Style Questionnaire did not adequately reflect the perceived influence of teacher actions on students\u27 success and failure experiences. The CAAS includes the common attributional areas of effort, ability and luck, but it also addresses the area of teacher input rather than the common area of task difficulty. The CAAS addresses both positive and negative outcomes related to course performance. The CAAS was administered on the first day of class to a large group of undergraduate students enrolled in an introductory human development course. Students took either a forced-choice or Likert version of the CAAS. The information gathered from the CAAS was used to determine general attributional style as it relates to different aspects of course performance. The students also responded to a brief rating scale of possible contributors to specific exam performance the day after receiving feedback on each of five unit exams. The brief exam rating scale addressed the attributional areas of effort, ability, and teacher input as they related specifically to performance on the exams. The participants of the study consisted of undergraduate students enrolled in a human development course at a large state university. A total of 306 students participated in some phase of the study. The participants consisted of more females than males, with the majority of the students being sophomores and juniors. The course was offered through the College of Education under the title of Psychoeducational Issues in Human Development. Developmental themes provided the framework for five course units. The five class sessions in each unit followed a standard sequence: session one involved viewing and discussing a videotape; sessions two and three consisted on an instructor overview; session four began with a brief essay quiz and then continued with the instructor overview; and session five included a multiple-choice exam and feedback regarding their score on the essay quiz and the exam. Results from different dimensions and versions of the CAAS indicated that students perceived personal effort as the primary contributor to academic successes and failures, with teacher input, personal ability, and luck following in order. In contrast, the exam ratings ranked both teacher input and student ability more highly than student effort. The Likert dimensions of the attributional questionnaire correlated more strongly with the performance measures than did the forced-choice dimensions, and all three of the exam rating dimensions (effort, ability, and teacher input) generally correlated with exam performance. Students\u27 perception of their ability was most strongly linked to exam performance. Students scoring high and low on the exams did not differ significantly on their perceived effort in preparing for the exams, but they consistently differed in their ratings of exam-related ability and teacher input. High performers consistently rated their ability to master course content and the teacher\u27s management of instructional and assessment procedures more highly than did the low-performing students

An Entailment Relation for Reasoning on the Web

Reasoning on the Web is receiving an increasing attention because of emerging fields such as Web adaption and Semantic Web. Indeed, the advanced functionalities striven for in these fields call for reasoning capabilities. Reasoning on the Web, however, is usually done using existing techniques rarely fitting the Web. As a consequence, additional data processing like data conversion from Web formats (e.g. XML or HTML) into some other formats (e.g. classical logic terms and formulas) is often needed and aspects of the Web (e.g. its inherent inconsistency) are neglected. This article first gives requirements for an entailment tuned to reasoning on the Web. Then, it describes how classical logic’s entailment can be modified so as to enforce these requirements. Finally, it discusses how the proposed entailment can be used in applying logic programming to reasoning on the Web

Estimating local car ownership models

Many studies in the transport demand literature have shown that income is an important factor in determining how many cars a household owns. When the models used to measure the strength of this relationship are estimated on cross-sectional data, they typically yield one overall value as the estimate. Local circumstances will, however, vary. This paper illustrates the use of the Geographically Weighted Regression technique to estimate the individual strength of this relationship for each of the United Kingdom electoral wards. Use of this type of model enables a wards’ income elasticity to be based on both the local estimate of the strength of this relationship and the current local level of car ownership. How the use of this local elasticity changes future forecasts of the size of the vehicle fleet is illustrated

Phage display-derived inhibitor of the essential cell wall biosynthesis enzyme MurF

Background To develop antibacterial agents having novel modes of action against bacterial cell wall biosynthesis, we targeted the essential MurF enzyme of the antibiotic resistant pathogen Pseudomonas aeruginosa. MurF catalyzes the formation of a peptide bond between D-Alanyl-D-Alanine (D-Ala-D-Ala) and the cell wall precursor uridine 5'-diphosphoryl N-acetylmuramoyl-L-alanyl-D-glutamyl-meso-diaminopimelic acid (UDP-MurNAc-Ala-Glu-meso-A2pm) with the concomitant hydrolysis of ATP to ADP and inorganic phosphate, yielding UDP-N-acetylmuramyl-pentapeptide. As MurF acts on a dipeptide, we exploited a phage display approach to identify peptide ligands having high binding affinities for the enzyme. Results Screening of a phage display 12-mer library using purified P. aeruginosa MurF yielded to the identification of the MurFp1 peptide. The MurF substrate UDP-MurNAc-Ala-Glumeso-A2pm was synthesized and used to develop a sensitive spectrophotometric assay to quantify MurF kinetics and inhibition. MurFp1 acted as a weak, time-dependent inhibitor of MurF activity but was a potent inhibitor when MurF was pre-incubated with UDP-MurNAc-Ala-Glu-meso-A2pm or ATP. In contrast, adding the substrate D-Ala-D-Ala during the pre-incubation nullified the inhibition. The IC50 value of MurFp1 was evaluated at 250 μM, and the Ki was established at 420 μM with respect to the mixed type of inhibition against D-Ala-D-Ala. Conclusion MurFp1 exerts its inhibitory action by interfering with the utilization of D-Ala-D-Ala by the MurF amide ligase enzyme. We propose that MurFp1 exploits UDP-MurNAc-Ala-Glu-meso-A2pm-induced structural changes for better interaction with the enzyme. We present the first peptide inhibitor of MurF, an enzyme that should be exploited as a target for antimicrobial drug development

Transcriptomic response to shell damage in the Antarctic clam, Laternula elliptica: time scales and spatial localisation

Mollusc shell is built up by secretion from the mantle and is the result of a controlled biological process termed biomineralisation. In general mollusc shells are well characterised however, the molecular mechanisms used by molluscs to produce shell remain largely unknown. One tractable method to study molecular biomineralisation mechanisms are shell damage-repair experiments, which stimulate calcification pathways. The present study used the Antarctic clam (Laternula elliptica) as a model to better understand when and where molecular biomineralisation events occur in the mantle. Two approaches were used: one experiment used high-throughput RNA-sequencing to study molecular damage-repair responses over a 2 month time series, and a second experiment used targeted semi-quantitative PCR to investigate the spatial location of molecular mechanisms in response to damage. Shell repair in L. elliptica was slow, lasting at least 2 months, and expression results revealed different biological processes were important at varying time scales during repair. A spatial pattern in relation to a single drilled hole was revealed for some, but not all, candidate genes suggesting the mantle may be functionally zoned and can respond to damage both locally and ubiquitously across the mantle. Valuable data on the temporal and spatial response of shell damage-repair provide a baseline not only for future studies in L. elliptica, but also other mollusc

Measuring Coverage of Prolog Programs Using Mutation Testing

Testing is an important aspect in professional software development, both to avoid and identify bugs as well as to increase maintainability. However, increasing the number of tests beyond a reasonable amount hinders development progress. To decide on the completeness of a test suite, many approaches to assert test coverage have been suggested. Yet, frameworks for logic programs remain scarce. In this paper, we introduce a framework for Prolog programs measuring test coverage using mutations. We elaborate the main ideas of mutation testing and transfer them to logic programs. To do so, we discuss the usefulness of different mutations in the context of Prolog and empirically evaluate them in a new mutation testing framework on different examples.Comment: 16 pages, Accepted for presentation in WFLP 201

Outcome Assessment Of A Management Program Using A Portfolio Approach: Lessons Learned

Over the past two decades the interest and use of student portfolios for assessing student learning outcomes has grown considerably.  This paper presents an overview of the portfolio approach to outcome assessment adopted by the Department of Management at California State University, San Bernardino and discusses major issues encountered over six years of implementation.  Experiences connected with the portfolio process are discussed from the perspectives of administrative complexity, the impact on academic program quality and evidence of assurance of student learning in relation to program learning objective