Showing papers by "Jordan University of Science and Technology published in 1999"

Summarizing text documents: sentence selection and evaluation metrics

Abstract: Human-quality text summarization systems are di cult to design, and even more di cult to evaluate, in part because documents can di er along several dimensions, such as length, writing style and lexical usage. Nevertheless, certain cues can often help suggest the selection of sentences for inclusion in a summary. This paper presents our analysis of news-article summaries generated by sentence selection. Sentences are ranked for potential inclusion in the summary using a weighted combination of statistical and linguistic features. The statistical features were adapted from standard IR methods. The potential linguistic ones were derived from an analysis of news-wire summaries. To evaluate these features we use a normalized version of precision-recall curves, with a baseline of random sentence selection, as well as analyze the properties of such a baseline. We illustrate our discussions with empirical results showing the importance of corpus-dependent baseline summarization standards, compression ratios and carefully crafted long queries.

Mutations in the CCN gene family member WISP3 cause progressive pseudorheumatoid dysplasia.

Abstract: Members of the CCN (for CTGF, cyr61/cef10, nov) gene family encode cysteine-rich secreted proteins with roles in cell growth and differentiation1. Cell-specific and tissue-specific differences in the expression and function of different CCN family members suggest they have non-redundant roles. Using a positional-candidate approach, we found that mutations in the CCN family member WISP3 are associated with the autosomal recessive skeletal disorder progressive pseudorheumatoid dysplasia (PPD; MIM 208230). PPD is an autosomal recessive disorder that may be initially misdiagnosed as juvenile rheumatoid arthritis2,3,4,5. Its population incidence has been estimated at 1 per million in the United Kingdom4, but it is likely to be higher in the Middle East and Gulf States6. Affected individuals are asymptomatic in early childhood2,3. Signs and symptoms of disease typically develop between three and eight years of age. Clinically and radiographically, patients experience continued cartilage loss and destructive bone changes as they age2,3,4,5,6,7, in several instances necessitating joint replacement surgery by the third decade of life. Extraskeletal manifestations have not been reported in PPD. Cartilage appears to be the primary affected tissue, and in one patient, a biopsy of the iliac crest revealed abnormal nests of chondrocytes and loss of normal cell columnar organization in growth zones5. We have identified nine different WISP3 mutations in unrelated, affected individuals, indicating that the gene is essential for normal post-natal skeletal growth and cartilage homeostasis.

Dental Discoloration: An Overview

Abstract: Often the first evidence of variation from normal in human dentition is an observable difference in the color of the teeth. During the past decade, the demand for conservative esthetic dentistry has grown dramatically. Tooth discoloration is a frequent dental finding, associated with clinical and esthetic problems. It differs in etiology, appearance, composition, location, severity, and firmness in adherence to the tooth surface. Basically, there are two types of tooth discolorations: those caused by extrinsic factors and those caused by intrinsic congenital or systemic influence. The intensity of stains may be worsened if there are enamel defects. Tooth discoloration presents two major challenges to the dental team. The first challenge is to ascertain the cause of the stain; the second is its management.

A Simulated Annealing Algorithm with Constant Temperature for Discrete Stochastic Optimization

Abstract: We present a modification of the simulated annealing algorithm designed for solving discrete stochastic optimization problems. Like the original simulated annealing algorithm, our method has the hill climbing feature, so it can find global optimal solutions to discrete stochastic optimization problems with many local solutions. However, our method differs from the original simulated annealing algorithm in that it uses a constant (rather than decreasing) temperature. We consider two approaches for estimating the optimal solution. The first approach uses the number of visits the algorithm makes to the different states (divided by a normalizer) to estimate the optimal solution. The second approach uses the state that has the best average estimated objective function value as estimate of the optimal solution. We show that both variants of our method are guaranteed to converge almost surely to the set of global optimal solutions, and discuss how our work applies in the discrete deterministic optimization setting. We also show how both variants can be applied for solving discrete optimization problems when the objective function values are estimated using either transient or steady-state simulation. Finally, we include some encouraging numerical results documenting the behavior of the two variants of our algorithm when applied for solving two versions of a particular discrete stochastic optimization problem, and compare their performance with that of other variants of the simulated annealing algorithm designed for solving discrete stochastic optimization problems.

A machine learning approach to building domain-specific search engines

Abstract: Domain-specific search engines are becoming increasingly popular because they offer increased accuracy and extra features not possible with general, Web-wide search engines. Unfortunately, they are also difficult and time-consuming to maintain. This paper proposes the use of machine learning techniques to greatly automate the creation and maintenance of domain-specific search engines. We describe new research in reinforcement learning, text classification and information extraction that enables efficient spidering, populates topic hierarchies, and identifies informative text segments. Using these techniques, we have built a demonstration system: a search engine for computer science research papers available at www.cora.justrcsettrch.com.

Antibacterial Activity of Jordanian Medicinal Plants

Abstract: The antibacterial activity of ethanol extracts of 15 plant species used in the traditional medicine in Jordan and other Middle East countries were tested. Extracts of certain parts of these plants were tested in vitro against 14 pathogenic bacterial species and strains using the agar diffusion method. Results evaluated as the diameter of inhibition zone of bacterial growth showed that 25 mg/well of 12 plant extracts have antibacterial activity on one or more of the tested bacteria. Three plants exhibited broad spectrum antibacterial activity: Punica granatum L., Quercus infectoria Olive., and Rhus coriaria L. The most susceptible bacteria were Pseudomonas aeruginosa, Bacillus cereus and Streptococcus pyogenes (ATCC 12351), and the most resistant species were Escherichia coli (ATCC 25922 and clinical isolates), Klebsiella pneumoniae, Shigella dysentriae (ATCC 49345), and Yersinia enterocolitica (ATCC 9610). The minimum inhibitory concentrations (MIC) of active extracts ranged from 4‐32 mg/ml while the minimum bactericidal concentrations (MBC) were exerted at higher doses 8‐62 mg/ml.

Complexity reduction of the NLMS algorithm via selective coefficient update

Abstract: This article proposes an algorithm for partial update of the coefficients of the normalized least mean square (NLMS) finite impulse response (FIR) adaptive filter. It is shown that while the proposed algorithm reduces the complexity of the adaptive filter, it maintains the closest performance to the full update NLMS filter for a given number of updates. Analysis of the MSE convergence and steady-state performance for independent and identically distributed (i.i.d.) signals is provided for the extreme case of one update/iteration.

Radiographic evaluation of mandibular third molar eruption space.

Abstract: Objective. The purpose of this study was to investigate variables in third molar and arch dimensions among subjects with impacted and erupted mandibular third molars. Study Design. Standardized panoramic radiographs were taken for 134 subjects (60 males and 74 females with 213 third molars) with an average age of 19.8 years. For the impacted group, only those who had mesioangular inclination of the third molars were recorded. The radiographic features studied were angulation of tooth, level of eruption, development of root, mesiodistal crown width, retromolar space, and gonial angle. Results. Third molar angulation in the impacted group (69 subjects with 101 third molars) averaged 16.28 degrees (SD ± 11.88 degrees), with no significant gender differences. The retromolar space was significantly smaller in the impacted group than in the erupted group (P < .001). This space was also the only significant variable (P < .05) associated with lateral asymmetry in the eruption/impaction status of third molars. In the impacted group, 83% of subjects had third molar space/crown width ratios less than 1, whereas in the erupted group 69% had ratios of at least 1. The average space/crown width ratios in the impacted and erupted groups were 0.78 and 1.06, respectively (P < .001). The impacted and erupted groups did not differ significantly with respect to mesiodistal crown width and gonial angle. Approximately 76% of impacted third molars had complete root formation, 20% had two thirds root formation, and only 4% displayed one third root formation. Of the impacted third molars, 66% were partially erupted and the rest were unerupted. There was a strong positive relationship between frequency of third molar impaction and degree of angulation (P < .001), but the former was inversely associated with retromolar space (P < .001). Conclusions. The most significant variable associated with third molar impaction is inadequate space. The vast majority of impacted third molars had space/crown width ratios of less than 1. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1999;88:285-91)

Clinical problems associated with unusual cases of talon cusp.

Abstract: CASE REPORT Talon cusp is an uncommon dental anomaly manifested as an accessory cusp-like structure on the crown of anterior teeth. This report describes two unusual cases of talon cusp. Case 1 showed bilateral anomalous cusps on the palatal aspects of maxillary supernumerary teeth, causing premature contact and tooth impaction. In case 2, a double-fused talon cusp was projected from the palatal surface of a large geminated central incisor. A talon cusp is not an innocuous defect, as it may provide a substantial diagnostic, treatment planning and procedural challenge. Early diagnosis and management are important to avoid complications.

Solar Collectors with Tubes Partially Filled with Porous Substrates

Abstract: In this work, the thermal performance of a conventional collector is improved by inserting porous substrates at the inner walls of the collector tubes. The porous substrates improve the convective heat transfer coefficient between the tube wall and the fluid. This improvement is investigated numerically and its effects on the efficiency and the useful gain of the collector are evaluated. It is found that inserting the porous substrate may raise the collector efficiency considerably, especially at high values of the overall heat loss coefficient.

Ultra-summarization (poster abstract): a statistical approach to generating highly condensed non-extractive summaries

Abstract: Abstract Using current extractive summarization techniques, it is impossible to produce a coherent document summary shorter than a single sentence, or to produce a summary that conforms to particular stylistic constraints. Ideally, one would prefer to understand the document, and to generate an appropriate summary directly from the results of that understanding. Absent a comprehensive natural language understanding system, an approximation must be used. This paper presents an alternative statistical model of a summarization process, which jointly applies statistical models of the term selection and term ordering process to produce brief coherent summaries in a style learned from a training corpus.

Lack of effectiveness of dexamethasone in neonatal bacterial meningitis.

Abstract: A clinical trial was conducted to determine whether dexamethasone as adjunctive therapy alters the outcome of bacterial meningitis in neonates. Fifty-two full-term neonates with bacterial meningitis were enrolled in a prospective study. Infants were alternately assigned to receive either dexamethasone or not. Twenty-seven received dexamethasone in addition to standard antibiotic treatment and 25 received antibiotics alone. Dexamethasone therapy was started 10–15 min before the first dose of antibiotics in a dose of 0.15 mg/kg per 6 h for 4 days. Baseline characteristics, clinical and laboratory features in the two groups were virtually similar. Both groups showed a similar clinical response and similar frequency of mortality and sequelae. Six (22%) babies in the treatment group died compared to 7 (28%) in the control group (P = 0.87). At follow up examinations up to the age of 2 years, 6 (30%) of dexamethasone recipients and 7 (39%) of the control group had mild or moderate/severe neurological sequelae. Audiological sequelae were seen in two neonates in the dexamethasone group compared to one in the control group.

Biosorption of phenol by chicken feathers

Abstract: This work aimed at exploring the potential use of chicken feathers as a biosorbent for the removal of phenol from aqueous solutions. Batch kinetics and isotherm studies were performed to evaluate the effects of process parameters such as pH, temperature, initial phenol concentration, and sorbent concentration. Complete adsorption of phenol was noticed under certain process conditions. The adsorption of phenol increased with increasing initial phenol concentration, solution pH, temperature, and sorbent concentration. The adsorption equilibrium was well represented by the Freundlich and Langmuir adsorption isotherm models. The thermodynamic parameters obtained by means of the Langmuir model showed that the adsorption process was endothermic.

Characterization and analysis of antibiotic activity of some aquatic actinomycetes.

Abstract: Nine different isolates of aquatic actinomycetes identified as Streptomyces spp. were studied for their morphological and cultural characteristics. One of these isolates (C 4 -S, Streptomyces violaceusniger) was extensively studied for its inhibitory effect against a wide range of Gram-positive, Gram-negative bacteria, Mycobacterium vaccae ATCC 29678, Candida albicans and several food associated filamentous fungi and yeasts. Most of these were characterized by flexous sporophore morphology and their inability to produce cultural pigments. Bioassay results indicated that S. violaceusniger of 10 days culture age was highly active against Gram-positive cocci and bacilli with an inhibition zone of 16-25 mm, and slightly active against M. vaccae ATCC 29678 with an inhibition zone of 5-10 mm. The inhibitory effect was slight against Escherichia coli, Aspergillus niger 1 and C. albicans with an inhibition zone of 8-10 mm for each of them. There was no inhibitory effect of S. violaceusniger against other Gram-negative bacteria, filamentous fungi and yeast. The nature of the active molecule produced by S. violaceusniger showed a maximum absorption in the UV region at 210-260 nm.

Three-body wear associated with three ceramics and enamel.

Abstract: Statement of problem Wear of human enamel is a clinical concern whenever opposing teeth need to be restored using ceramic restorations Purpose This in vitro study investigated wear of human enamel and 3 dental ceramics: a conventional porcelain (Vitadur Alpha), a low-fusing hydrothermal ceramic (Duceram-LFC), and a machinable ceramic (Vita Mark II) in a 3-body wear test Material and methods Thirty pairs of tooth-ceramic specimens were tested in a dental wear machine, under a standard load (40 N), rate (80 cycles/minute), and for 25,000 cycles in a simulated food slurry medium Amount of wear was determined by measuring the height loss of the tooth and depth of wear track of the ceramic materials Analysis of variance (ANOVA) was used to analyze the data, followed by Bonferroni multiple comparisons method to produce sets of simultaneous 95% confidence intervals Results ANOVA revealed significant differences between the groups for both enamel wear ( P =002) and ceramic wear ( P Conclusion The abrasiveness of Alpha porcelain and Duceram-LFC ceramic was similar, yet both were significantly more abrasive than Vita Mark II ceramic In addition, Vita Mark II was the most wear resistant ceramic and Duceram-LFC ceramic the least resistant (J Prosthet Dent 1999;82:476-81)