A performance comparison of the contiguous allocation strategies in 3D mesh connected multicomputers

The performance of contiguous allocation strategies can be significantly affected by the distribution of job execution times. In this paper, the performance of the existing contiguous allocation strategies for 3D mesh multicomputers is re-visited in the context of heavy-tailed distributions (e.g., a Bounded Pareto distribution). The strategies are evaluated and compared using simulation experiments for both First-Come-First-Served (FCFS) and Shortest-Service-Demand (SSD) scheduling strategies under a variety of system loads and system sizes. The results show that the performance of the allocation strategies degrades considerably when job execution times follow a heavy-tailed distribution. Moreover, SSD copes much better than FCFS scheduling strategy in the presence of heavy-tailed job execution times. The results also show that the strategies that depend on a list of allocated sub-meshes for both allocation and deallocation have lower allocation overhead and deliver good system performance in terms of average turnaround time and mean system utilization

Physiological Interactions Of Calcium And Vitamin D In Colon

This study aimed to review the literature about possible physiological interactions of calcium and vitamin D in colon. Previous studies have indicated to protective effects of vitamin D and calcium in case of colon cancers. We wanted to check the physiological effects of both of vitamin D and calcium, and either of each of them alone. We suggested effects of metabolism through induction of changes in the levels of various biomarkers that have influences in carcinogenesis including p53, heat shock proteins, iNOS and WT1 gene

The impact of internal service quality on job satisfaction in the hotel industry

Service quality is a key factor for success in any hotel. Many researchers have conducted studies on service quality, but only a few studies have been conducted on internal service quality (ISQ) in general, and in the hotel industry in particular. Since there is no general agreement among researchers on the measurement of ISQ, many studies have used SERVQUAL instrument to measure the employees’ perceptions of ISQ. The purpose of this study is to explore the influence of ISQ on employee’s job satisfaction in five-star hotels in Jordan. The current study was carried out by measuring the data gathered through a seven-point Likert scale. The quantitative survey method was applied, and therefore the SERVQUAL instrument was used to measure ISQ, and the Job Satisfaction Survey (JSS) was used to measure job satisfaction. Data obtained from a sample of 238 respondents drawn from 14 five-star hotels in Jordan were analysed with the SPSS software based on descriptive statistics. The study’s findings indicated that the ISQ of five-star hotels in Jordan has a significantly positive influence on an employee’s job satisfaction. These findings support the hypothesis that there is a positive relationship between ISQ in the hotel industry and industry employees’ job satisfaction.Keywords: hotels, internal service quality, job satisfactio

Case report of a rare thumb exostosis

Thumb exostosis is a rare, benign, and acquired bony tumor of the distal phalanx of the thumb, the mass itself is typically painless, but pressure on the nail plate can result in pain and deformity of the involved digit. This study was conducted at King Hussein Medical Centre in Amman, Jordan. A 38-year-old male patient, medically free, presented with a right thumb ulnar aspect hard mass, and pain at that site of his thumb. He started to notice it since 1 year. On examination, a hard bony lesion around 1×1 cm in size was present on the ulnar aspect of the right thumb tip, with tight but healthy skin over it. X-ray radiographs of the hand showed a bony lesion in continuity with thumb distal phalanx ulnar aspect native cortical bone. Excisional biopsy was done from dead ulnar approach without nail bed removal was done, and histopathology result confirmed the diagnosis of thumb exostosis and no recurrence occurred either on clinical or radiological follow up till date.

Optical, electrical and chemical properties of PEO:I2 complex composite films

Synthesized PEO:I2 complex composite films with different I2 concentrations were deposited onto fused silica substrates using a dip-coating method. Incorporation of PEO films with I2 increases the electrical conductivity of the composite, reaching a maximum of 46 mS/cm for 7 wt% I2. The optical and optoelectronic properties of the complex composite films were studied using the transmittance and reflectance spectra in the UV-Vis region. The transmittance of PEO decreases with increasing I2 content. From this study, the optical bandgap energy decreases from 4.42 to 3.28 eV as I2 content increases from 0 to 7 wt%. In addition, the refractive index for PEO films are in the range of 1.66 and 2.00.1H NMR spectra of pure PEO film shows two major peaks at 3.224 ppm and 1.038 ppm, with different widths assigned to the mobile polymer chains in the amorphous phase, whereas the broad component is assigned to the more rigid molecules in the crystalline phase, respectively. By adding I2 to the PEO, both peaks (amorphous and crystal) are shifted to lower NMR frequencies indicating that I2 is acting as a Lewis acid, and PEO is acting as Lewis base. Hence, molecular iodine reacts favorably with PEO molecules through a charge transfer mechanism, and the formation of triiodide (I3-), the iodite (IO2-) anion, I 2· · · PEO and I2+···PEO complexes. PEO:I2 complex composite films are expected to be suitable for optical, electrical, and optoelectronic applications

Assessment of radioactivity contents in bedrock groundwater samples from the northern region of Saudi Arabia

Recognizing the vast uses of water in human life, the presence of α and β particles emitting radionuclides in groundwater of northern Saudi Arabia has been evaluated as a means of water quality assessment of the region. A liquid scintillation counting technique was used to determine the gross α/β, and 228Ra radioactivities in water samples, while the radioactivity concentrations of 234,238U and 226Ra were determined using alpha spectrometry after the separation process. Present results show that all water samples contain a higher level of gross α and β radioactivity than the WHO recommended limits; the average gross α activity is about 7 times greater than the limit value of 0.5 Bq L−1, while the average gross β activity value is about 3.5 times greater than the limit value of 1 Bq L−1. Correlations of TDS and pH with gross α and β radioactivity in the studied samples were investigated. The activity ratio of the measured U and Ra alpha emitters to the gross α radioactivity and the ratio of the measured β emitters to gross β radioactivity were also discussed. Furthermore, interesting information on thorium abundance and radioactive disequilibrium in U series were observed by studying the activity ratio of 228Ra/226Ra, 226Ra/238U, and 234U/238U. Although these samples are not directly used for human being drinking, and mainly used in irrigation, the higher gross α/β radioactivity may cause health risks to humans, since these radionuclides may enter the food chain through irrigation water. Thus, further radioactive risk assessment is highly recommended

MEDIATING ROLE OF EMPOWERMENT BETWEEN TOTAL QUALITY MANAGEMENT (TQM) AND SERVICE RECOVERY PERFORMANCE IN THE HOTEL INDUSTRY

The purpose of this research was to examine the mediating effect of empowerment on the linkage between Total Quality Management (TQM) and service recovery performance in the hotel industry. Although much has been written about TQM, empowerment and service recovery performance, but the role of empowerment as a mediator in the relationship between TQM and service recovery performance has remained a relatively unexplored research area. A 93-item questionnaire is designed to measure TQM, empowerment and service recovery amongst employees in five-star hotels in Jordan, and 254 usable questionnaires were used in this study. Principal components analysis determined the factor structure and regression analysis determined the relationships between the study’s variables. The results revealed that the TQM implementations have positive effects on empowerment and service recovery performance. Moreover, the study found the full mediating effect of empowerment in the relationship between TQM and service recovery performance. Implications, limitations and future research are discussed at the end. This study proposes model of influence of TQM in service recovery performance, whereby empowerment fully mediates this relationship

An Evolutionary Reduction Principle for Mutation Rates at Multiple Loci

A model of mutation rate evolution for multiple loci under arbitrary selection is analyzed. Results are obtained using techniques from Karlin (1982) that overcome the weak selection constraints needed for tractability in prior studies of multilocus event models. A multivariate form of the reduction principle is found: reduction results at individual loci combine topologically to produce a surface of mutation rate alterations that are neutral for a new modifier allele. New mutation rates survive if and only if they fall below this surface - a generalization of the hyperplane found by Zhivotovsky et al. (1994) for a multilocus recombination modifier. Increases in mutation rates at some loci may evolve if compensated for by decreases at other loci. The strength of selection on the modifier scales in proportion to the number of germline cell divisions, and increases with the number of loci affected. Loci that do not make a difference to marginal fitnesses at equilibrium are not subject to the reduction principle, and under fine tuning of mutation rates would be expected to have higher mutation rates than loci in mutation-selection balance. Other results include the nonexistence of 'viability analogous, Hardy-Weinberg' modifier polymorphisms under multiplicative mutation, and the sufficiency of average transmission rates to encapsulate the effect of modifier polymorphisms on the transmission of loci under selection. A conjecture is offered regarding situations, like recombination in the presence of mutation, that exhibit departures from the reduction principle. Constraints for tractability are: tight linkage of all loci, initial fixation at the modifier locus, and mutation distributions comprising transition probabilities of reversible Markov chains.Comment: v3: Final corrections. v2: Revised title, reworked and expanded introductory and discussion sections, added corollaries, new results on modifier polymorphisms, minor corrections. 49 pages, 64 reference

Delayed intravitreal anti-vegf therapy for patients during the covid-19 lockdown: An ethical endeavor

Purpose: To assess the impact of Jordanian’s Corona Virus Disease (COVID-19) lockdown on visual acuity and macular thickness in patients with macular edema receiving intravitreal injections, and to assess the ethical endeavor of lockdown among serious sight threatening conditions. Patients and Methods: This retrospective observational study included patients planned for intravitreal injections who did not complete the planned course before the lockdown (ie, before 20th of March 2020). Data included demographics, indication for the intravitreal injection, corrected distance visual acuity (CDVA), and central macular thickness on Optical Coherence Tomography (OCT) before and after the lockdown. Results: One-hundred and sixty-six eyes of 125 patients were studied, 68 (54.4%) patients were males, and the mean (± standard deviation, SD) age was 64.79 (±9.41) years. Mean (±SD) duration of delay in the planned injection was 60.97 (±24.35) days. The change in visual acuity was statistically significant for patients with diabetic macular edema (p= 0.045 improvement), patients with central retinal vein thrombosis (CRVO) (p= 0.05 deterioration), and patients with age-related macular degeneration (AMD) (p= 0.005 deterioration). Of interest, delay of more than 2 months and the previous need for 3 or more injections were significant poor prognostic factors for visual outcome for patients with diabetic macular edema (p=0.027 and 0.045). Conclusion: The impact of delay in the scheduled intravitreal injections resulted in variable outcomes depending on the indication. Triaging the urgency of patients should be based on the indication to support the equity principle of bioethics, where those in need are prioritized against others, depending on potential adverse outcome