Showing papers by "Jordan University of Science and Technology published in 2005"

Linear array geometry synthesis with minimum sidelobe level and null control using particle swarm optimization

Abstract: This paper describes the synthesis method of linear array geometry with minimum sidelobe level and null control using the particle swarm optimization (PSO) algorithm. The PSO algorithm is a newly discovered, high-performance evolutionary algorithm capable of solving general N-dimensional, linear and nonlinear optimization problems. Compared to other evolutionary methods such as genetic algorithms and simulated annealing, the PSO algorithm is much easier to understand and implement and requires the least of mathematical preprocessing. The array geometry synthesis is first formulated as an optimization problem with the goal of sidelobe level (SLL) suppression and/or null placement in certain directions, and then solved by the PSO algorithm for the optimum element locations. Three design examples are presented that illustrate the use of the PSO algorithm, and the optimization goal in each example is easily achieved. The results of the PSO algorithm are validated by comparing with results obtained using the quadratic programming method (QPM).

Effects of drought stress on growth and yield of barley

Abstract: Barley (Hordeum vulgare) grown in Mediterranean regions undergoes drought stress during the grain-filling period. A greenhouse experiment was conducted to study the effect of drought stress on grain growth and yield of barley. Plants were exposed to three drought treatments at the beginning of grain filling: (1) well-watered at 100% field capacity, (2) mild drought stress at 60% field capacity, and (3) severe drought stress at 20% field capacity until grain maturity. Grain moisture content and dry weight were determined for grains harvested at 3, 10, 17, 23 and 31 days after the beginning of grain filling. Grain dry weight for severe drought stress plants reached a maximum value earlier than grains from mild drought stress and well-watered plants, indicating that grains from severe drought stress plants had a higher growth rate than those of mild drought stress and well-watered plants. Drought-stressed plants had shorter duration of grain filling than well-watered plants. Drought stress treatments reduced grain yield by reducing the number of tillers, spikes and grains per plant and individual grain weight. In conclusion, postanthesis drought stress was detrimental to grain yield regardless of the stress severity.

Periodontal Diseases and the Risk of Preterm Birth and Low Birth Weight: A Meta-Analysis

Abstract: Background: This meta-analysis of periodontal disease in relation to the risk of preterm birth/low birth weight (PTB/ LBW) is based on two case-control studies and three prospective cohort studies that met prestated inclusion criteria. Methods: Information on the designs of the studies, characteristics of the study population, exposure and outcome measures, control for confounders, and risk estimates were abstracted independently by two investigators using a standard protocol. Results: Pregnant women with periodontal disease had an overall adjusted risk of preterm birth that was 4.28 (95% confidence interval [CI], 2.62 to 6.99; P <0.005) times that risk for healthy subjects. The overall adjusted odds ratio of preterm low birth weight was 5.28 (95% CI, 2.21 to 12.62; P <0.005), while the overall adjusted odds ratio of a delivery of either PTB or LBW was 2.30 (95% CI, 1.21 to 4.38; P <0.005). Conclusions: Our findings indicate that periodontal diseases in the pregnant mother significantly increase the risk ...

Self-perception of malocclusion among north jordanian school children

Abstract: This study was undertaken to assess the factors affecting self-perception and the demand for orthodontic treatment among north Jordanian school children. In total, 1404 students randomly selected to represent five geographical areas of northern Jordan were examined. The students were further subgrouped according to gender (858 females, 546 males), age (985 13 year olds, 419 17 year olds) and rural/urban place of residence (212 rural, 1192 urban). The aesthetic component (AC) of the Index of Orthodontic Treatment Need (IOTN) was used as an assessment measure of the need for orthodontic treatment. The self-perception of malocclusion was evaluated by asking each student to identify which photograph on the AC scale most closely matched the appearance of their anterior teeth. The demand for orthodontic treatment was measured by asking the students: "Do you feel it is necessary to have your teeth straightened by an orthodontist?" Differences between the self-perception of malocclusion among the different groups were tested using the chi-squared test.The results showed that the majority of students rated their dentition from grades 1 to 4, with a tendency for the females and older school children to score their teeth as more attractive than males and younger children (P < 0.05, P < 0.001, respectively). Rural and urban school children did not differ in the perception of their own dentition. The self-perception scores of subjects within the no aesthetic need, borderline need and definite need groups differed significantly (P < 0.001). The subjects who reported a definite need perceived their teeth to be worse than the other two groups. The demand for orthodontic treatment was found to be affected by gender (P < 0.01) and rural/urban areas of living (P < 0.05).

A quantitative analysis approach for cardiac arrhythmia classification using higher order spectral techniques

Abstract: Ventricular tachyarrhythmias, in particular ventricular fibrillation (VF), are the primary arrhythmic events in the majority of patients suffering from sudden cardiac death. Attention has focused upon these articular rhythms as it is recognized that prompt therapy can lead to a successful outcome. There has been considerable interest in analysis of the surface electrocardiogram (ECG) in VF centred on attempts to understand the pathophysiological processes occurring in sudden cardiac death, predicting the efficacy of therapy, and guiding the use of alternative or adjunct therapies to improve resuscitation success rates. Atrial fibrillation (AF) and ventricular tachycardia (VT) are other types of tachyarrhythmias that constitute a medical challenge. In this paper, a high order spectral analysis technique is suggested for quantitative analysis and classification of cardiac arrhythmias. The algorithm is based upon bispectral analysis techniques. The bispectrum is estimated using an autoregressive model, and the frequency support of the bispectrum is extracted as a quantitative measure to classify atrial and ventricular tachyarrhythmias. Results show a significant difference in the parameter values for different arrhythmias. Moreover, the bicoherency spectrum shows different bicoherency values for normal and tachycardia patients. In particular, the bicoherency indicates that phase coupling decreases as arrhythmia kicks in. The simplicity of the classification parameter and the obtained specificity and sensitivity of the classification scheme reveal the importance of higher order spectral analysis in the classification of life threatening arrhythmias. Further investigations and modification of the classification scheme could inherently improve the results of this technique and predict the instant of arrhythmia change.

Cytotoxicity evaluation of dental resin composites and their flowable derivatives.

Abstract: The release of components from dental composite into surrounding tissue may cause an adverse tissue reaction. Thus, this study investigated the cytotoxicity of three types of dental composites with their flowable derivatives and determined the compounds released from these materials by high-performance liquid chromatography (HPLC) analysis. Fifteen specimens from each composite (Admira, Z250, Tetric Ceram) with fifteen of their flowables (Admira Flow, Tetric Flow, Feltik Flow) were prepared in the form of discs and divided into two groups of 10 and 5 for each material. The first group (10 discs) was used to evaluate the cytotoxicity of the material on balb/c 3T3 fibroblasts by measuring cellular metabolic activity (3{4,5-dimethylthiazol-2-yl}-2,5-diphenyltetrazolium bromide [MTT] assay) relative to Teflon controls, while the second group (5 discs) was used to determine the leached components from each material into culture medium by HPLC analysis. The results revealed that Z250 and Tetric Ceram were less cytotoxic than their flowable derivatives. However, the ormocer, Admira, was significantly more cytotoxic than Admira Flow. Among the standard composites, Tetric Ceram was the least cytotoxic and Admira the most. Furthermore, Tetric flow was the most cytotoxic and Admira flow was significantly the least cytotoxic among the flowable materials tested. HPLC analysis revealed bisphenol A glycerolate dimethacrylate (bis-GMA) and triethylene glycol dimethacrylate (TEGDMA) in the eluates of all the materials, while urethane dimethacrylate (UDMA) was present in all eluates except that of Feltik Flow. In conclusion, the flowable derivatives are more cytotoxic than the traditional composites whereas the ormocer Admira Flow is less cytotoxic than the Admira composite.

Effect of ascorbic acid and dehydration on concentrations of total phenolics, antioxidant capacity, anthocyanins, and color in fruits.

Abstract: The purpose of this investigation was to report on the total phenolics, anthocyanins, and oxygen radical absorbance capacity (ORAC) of strawberry, peach, and apple, the influence of dehydration and ascorbic acid treatments on the levels of these compounds, and the effect of these treatments on fruit color. Results showed that fresh strawberry had the highest levels for total phenolics [5317.9 mg of chlorogenic acid equivalents (CAE)/kg], whereas lower levels were found in fresh apple and peach (3392.1 and 1973.1 mg of CAE/kg, respectively), and for anthocyanins (138.8 mg/kg), whereas lower levels were found in fresh apple and peaches (11.0 and 18.9 mg/kg, respectively; fresh strawberry had an ORAC value of 62.9 mM/kg Trolox equivalents. The fresh apple and peach were found to have ORAC values of 14.7 and 11.4 mM/kg of Trolox equivalents, respectively. The color values indicated that the addition of 0.1% ascorbic acid increased the lightness (L*) and decreased the redness (a*) and yellowness (b*) color values of fresh strawberry, peach, and apple, sliced samples, and the puree made from them. Also, results showed that dehydration is a good method to keep the concentrations of total phenolics and anthocyanins and ORAC values at high levels.

Gender-specific oral health attitudes and behavior among dental students in Jordan.

Abstract: The aim of this study was to determine the difference in oral health attitudes and behavior between male and female dental students at Jordan University of Science and Technology (JUST) A self-administered questionnaire based on a modified version of the Hiroshima University Dental Behavior Inventory (HU-DBI) was distributed among 375 dental students The response rate was 837% with 48% males and 52% females responding Female students reported brushing their teeth more frequently than male students (P<0001) Approximately 47% of the male students brushed their teeth less than twice daily compared to 21% of the female students Also, female students believed in the necessity of using toothpaste during brushing more often than male students (P<001) On the other hand, smoking was much more frequent among males than among females (31% vs 4%) (P<0001) Male students indicated they had been smoking for longer periods of time than female students This survey shows male students visit the dentist only when they have dental pain While this was more than their female peers, it was not statistically significant (P= 0056) In general the present study showed dental students in Jordan had poor oral health Further research is needed to examine the students clinically for periodontal and caries conditions Students should be encouraged to be a model for oral health for their families, friends, and patients

Knowledge and attitude of Jordanian school health teachers with regards to emergency management of dental trauma

Abstract: The purpose of this study was to assess, by means of a self administered structured questionnaire, the level of knowledge of school health teachers in northern Jordan with regards to the immediate emergency management of dental trauma. The questionnaire surveyed teacher's background, Knowledge of management of tooth fracture, avulsion, and loss of consciousness, it also investigated teacher's attitudes, and self assessed knowledge, as well as knowledge of availability of emergency services in Jordan. The sample consisted of all school health teachers in northern Jordan (220) who attended an oral health education course held by the Jordanian dental association. Only 190 were included in the survey. Sixty-three percent were females, 44% were in their twenties, and 43% in their forties. Their school health teaching experience ranged from 1 to 7 years. Only 20% were officially trained in school health. Less than half of the teachers received first aid training only once in their teaching career, not necessarily as part of school health training. Only 10 teachers were trained in dental first aid, and more than half had a previous experience with handling dental trauma in children. Overall the teachers' knowledge with regards to the emergency management of the trauma cases presented in the report was deficient. Chi-square test showed that, the difference in their responses to the knowledge part of the questionnaire was not statistically significant with regards to age, gender, years of teaching experience, first aid training, or number of seen trauma cases. Generally, the attitude was positive, most teachers wanting further education on the topic, however those who were trained in first aid, thought they were able to give proper action when needed in cases of trauma (P = 0.026). Most teachers were unsatisfied with their level of knowledge, and only 30% knew of the availability of after hour emergency services for dental trauma. The present report indicated the gross lack of knowledge among school health teachers with regards to dental trauma emergency management. Educational programs to improve the knowledge and awareness of this group of adults, who are usually the first line of advice in case of dental trauma in schools, are mandatory. These programs should be properly designed to insure that proper information is retained with a positive effect on attitude, and self assessed competence.

Performance analysis of the deficient length LMS adaptive algorithm

Abstract: In almost all analyzes of the least mean-square (LMS) finite impulse response (FIR) adaptive algorithm, it is assumed that the length of the adaptive filter is equal to that of the unknown system impulse response. However, in many practical situations, a deficient length adaptive filter, whose length is less than that of the unknown system, is employed, and analysis results for the sufficient length LMS algorithm are not necessarily applicable to the deficient length case. Therefore, there is an essential need to accurately quantify the behavior of the LMS algorithm for realistic situations where the length of the adaptive filter is deficient. In this paper, we present a performance analysis for the deficient length LMS adaptive algorithm for correlated Gaussian input data and using the common independence assumption. Exact expressions that completely characterize the transient and steady-state mean-square performances of the algorithm are developed, which lead to new insights into the statistical behavior of the deficient length LMS algorithm. Simulation experiments illustrate the accuracy of the theoretical results in predicting the convergence behavior of the algorithm.

Immunohistochemical evaluation of human epidermal growth factor receptor 2 and estrogen and progesterone receptors in breast carcinoma in Jordan.

Abstract: Although breast carcinoma (BC) is the most common malignancy affecting Jordanian females and the affected population in Jordan is younger than that in the West, no information is available on its biological characteristics. Our aims in this study are to evaluate the expression of estrogen receptor (ER) and progesterone receptor (PR) and Her-2/neu overexpression in BC in Jordan, and to compare the expression of these with other prognostic parameters for BC such as histological type, histological grade, tumor size, patients' age, and number of lymph node metastases. This is a retrospective study conducted in the Department of Pathology at Jordan University of Science and Technology. A confirmed 91 cases of BC diagnosed in the period 1995 to 1998 were reviewed and graded. We used immunohistochemistry to evaluate the expression of ER, PR, and Her-2. Immunohistochemical findings were correlated with age, tumor size, grade and axillary lymph node status. Her-2 was overexpressed in 24% of the cases. The mean age of Her-2 positive cases was 42 years as opposed to 53 years among Her-2 negative cases (p = 0.0001). Her-2 expression was inversely related to ER and PR expression. Her-2 positive tumors tended to be larger than Her-2 negative tumors with 35% overexpression among T3 tumors as opposed to 22% among T2 tumors (p = 0.13). Her-2 positive cases tended to have higher rates of axillary metastases, but this did not reach statistical significance. ER and PR positive cases were seen in older patients with smaller tumor sizes. Her-2 overexpression was seen in 24% of BC affecting Jordanian females. Her-2 overexpression was associated with young age at presentation, larger tumor size, and was inversely related to ER and PR expression. One-fifth of the carcinomas were Her-2 positive and ER negative. This group appears to represent an aggressive form of BC presenting at a young age with large primary tumors and a high rate of four or more axillary lymph node metastases.

Space conditions and dental and occlusal features in patients with palatally impacted maxillary canines: an aetiological study

Abstract: The aetiology of palatal canine impaction is unclear. The aim of this research was to investigate the occlusal features that could contribute to the aetiology of palatal maxillary canine impaction. The material consisted of the pre-treatment dental casts of 34 patients (27 female and seven male) with unilateral palatal canine impaction (impaction group). The average age of this group was 17.7 years (+/- 4.6). These were matched according to age, gender and type of malocclusion with a comparison group of pre-treatment dental casts from unaffected orthodontic patients. From the dental casts the following parameters were obtained: (1) dentoalveolar arch relationship, (2) missing or anomalous teeth, (3) the mesiodistal width of each maxillary tooth, (4) the upper arch perimeter, (5) the maxillary inter-premolar and inter-molar widths. The arch length-tooth size discrepancy was only calculated for subjects with no missing teeth. Palatal canine impaction occurred most frequently in subjects with a Class II division 2 malocclusion. There was an association between palatal canine impaction and anomalous lateral incisors (P = 0.01). The transverse arch dimension was significantly wider in the impaction group than in the comparison group (P 0.05). These results suggest that the presence of an 'excess palatal width' and anomalous lateral incisor may contribute to the aetiology of palatal canine impaction.

Dental anxiety in children and its relationship to dental caries and gingival condition

Abstract: The aim of this study was to determine the levels of dental anxiety, dental caries and gingivitis among 12-15-year-old schoolchildren, in Irbid Governorate/northern Jordan, and to evaluate the correlation between these variables. Two schools were selected by a simple random method from each of the five geographic areas in Irbid Governorate. All children (1021), from the 10 selected schools, who participated in this study completed a questionnaire modified from Kleinknecht's Dental Fear Survey (DFS questionnaire). Children underwent oral examination for dental caries and gingival condition, using Decayed, Missing and Filled Teeth (DMFT) Index and Loe and Silness Gingival Index (GI), respectively. Results of this survey showed that the prevalence of low to moderate 'general dental fear' among the study population was 43% while that of 'high dental fear' was 10%. The self-reported 'general fear of dental treatment' was higher among girls than boys. Fear of specific stimuli (pain) was the most common source of dental fear. The sight and sensation of the anaesthetic needle and the sight, sound and sensation of the drill were rated the most fear-eliciting stimuli. The mean DMFT (2.89) and GI (1.80) of boys was not significantly different from the DMFT (3.37) and GI (1.53) of girls (P > 0.05). Spearman's correlation test demonstrated no association between 'general dental fear' and dental caries (r = 0.06) or gingivitis (r = 0.007).

Recognition of Arabic sign language alphabet using polynomial classifiers

Abstract: Building an accurate automatic sign language recognition system is of great importance in facilitating efficient communication with deaf people. In this paper, we propose the use of polynomial classifiers as a classification engine for the recognition of Arabic sign language (ArSL) alphabet. Polynomial classifiers have several advantages over other classifiers in that they do not require iterative training, and that they are highly computationally scalable with the number of classes. Based on polynomial classifiers, we have built an ArSL system and measured its performance using real ArSL data collected from deaf people. We show that the proposed system provides superior recognition results when compared with previously published results using ANFIS-based classification on the same dataset and feature extraction methodology. The comparison is shown in terms of the number of misclassified test patterns. The reduction in the rate of misclassified patterns was very significant. In particular, we have achieved a 36% reduction of misclassifications on the training data and 57% on the test data.

Developing Free-Convection Gas Flow in a Vertical Open-Ended Microchannel Filled with Porous Media

Abstract: The developing hydrodynamic and thermal behaviors of free convection gas flow in a vertical open-ended parallel-plate microchannel filled with porous media are investigated numerically. The extended Darcy-Brinkman-Forchheimer model is used to model the flow in porous medium and the solid and fluid media are not assumed in local thermal equilibrium. The microflow regime considered is the slip flow regime. The slip in velocity and jump in temperature are found to decrease in the axial direction of the flow. The friction factor is found to decrease as Knudsen number, Forchheimer number and Grashof number are increased. However, the friction factor is found to increase as Darcy number increased. On the other hand, Nusselt number is found to decrease as Knudsen number, Darcy number and thermal conductivity ratio are increased, whereas it increased as Forchheimer number, Grashof number and Biot number are increased.

Achieving Success in Second Language Acquisition

Abstract: Part I. Learning: 1. Planning foreign-language study 2. The role of cognition in second language acquisition 3. Learning styles and learning strategies 4. Understanding feelings and personality in language learning 5. Interpersonal dynamics in the learning process Part II. Language: 6. Verbal languages 7. Sociolinguistics: the right expression 8. Unspoken communication Part III. Independence: 9. Self-regulation and learner autonomy 10. Controlling spoken and written communication.