A review and comparison of efficient flooding schemes for on-demand routing protocols on mobile ad hoc networks (MANETs)

Since the basic components of ad hoc wireless networks are mostly battery-operated portable devices, power conservation is one of the central issues of such networks. Power-conservative designs for ad hoc networks pose many challenges due to the lack of central coordination facilities. Existing on-demand routing protocols perform route discovery by flooding the network with a query message requesting a route to the destination. Flooding is used because of its simplicity and greater success in finding the best route between the source and destination available at that time of route discovery. However, as flooding involves querying all reachable network nodes, frequent flooding can rapidly deplete the energy reserved at each node. In addition to consuming significant portions of the available network bandwidth. Further, as the number of communicating nodes increases, more congestion, contention, and collisions can be expected. This paper reviews and compares approaches for optimizing bandwidth efficiency of route discovery, where several efficient flooding schemes have been presented based on different techniques to solve the problems related with the traditional blind flooding

An attempt to understand complexity in a government digital transformation project

Digital transformation projects will become one of the dominating tools for mastering digital transformation in governments. Studies show that such projects are complex undertakings and increasingly difficult to manage. The purpose of the paper is to provide a better understanding of the factors that cause complexity in government digital transformation projects. The authors use an in-depth case study approach to investigate factors of complexity in an ongoing digital transformation project. The results indicate that complexity in this project is rooted in dynamic relationships between multiple dimensions of organization, technologies, and innovation. The authors conclude that when organizational structuring, the introduction of new technology, and efforts to innovate and create added value for citizens and businesses operate in tandem, the pervasive complexity associated with delivering government digital transformation projects becomes increasingly difficult to manage

On the prediction of free turbulent jets with swirl using a quadratic pressure-strain model

Data from free turbulent jets both with and without swirl are used to assess the performance of the pressure-strain model of Speziale, Sarkar and Gatski which is quadratic in the Reynolds stresses. Comparative predictions are also obtained with the two versions of the Launder, Reece and Rodi model which are linear in the same terms. All models are used as part of a complete second-order closure based on the solution of differential transport equations for each non-zero component of the Reynolds stress tensor together with an equation for the scalar energy dissipation rate. For non-swirling jets, the quadratic model underestimates the measured spreading rate of the plane jet but yields a better prediction for the axisymmetric case without resolving the plane jet/round jet anomaly. For the swirling axisymmetric jet, the same model accurately reproduces the effects of swirl on both the mean flow and the turbulence structure in sharp contrast with the linear models which yield results that are in serious error. The reasons for these differences are discussed

Numerical Experimental Investigation of Solidification Thickness around Cylindrical Surfaces for HVAC Cold Storage Systems

Thermal Ice Storage System (TISS) is an innovative way of storing night-time off-peak energy for daytime peak USAge. In many locations, demand for electrical power peaks during summer time. Air-conditioning equipment are the main reason accounting for as much as half of the power demand during the hot mid-day hours when electricity is most expensive. Since utilities have spare electrical generating capacity at night, electricity generated during this ldquo;off-peakrdquo; is much less expensive. In this research a numerical model for Latent Heat Storage (LHS) cylindrical tank has been obtained from a numerical package, ANSYS software ver. 15, and compared to an experimental data gathered from similar tank. The data showed good agreement with the experimental data with an error of 9%. The numerical model can be used to estimate ice thickness and tank geometries for any future work

NEOPTERIN AND INTERFERON-GAMMA AS IMMUNE RESPONSE MARKERS IN BETATHALASSEMIA MAJOR PATIENTS

Objective: The assessment of neopterin and interferon-gamma (IFN-γ) levels as a part of immune system response about serum iron status in β-thalassemia (TM) major patients.Methods: Spectrophotometry applied for the estimation of iron status including serum iron level, total iron-binding capacity, and unsaturated iron-binding capacity. Enzyme-linked immunosorbent assay (ELISA) applied for the estimation of the serum cytokines included neopterin and IFN-γ also serum ferritin estimation by ELISA from 130 β-TM major patients where they divided according to serum ferritin level (< and ≥2500 ng/mL).Results: The neopterin and IFN-γ concentration showed significantly increased with direct correlation among TM patient group when compared to the normal healthy control group. However, there was no significant difference between different levels of serum ferritin.Conclusion: The increased serum level of neopterin and IFN-γ found in patients with β-TM may be due to the direct effect of iron on cellular immune cells beside of immune system response to the effect of iron toxicity on different body organs. There was a direct moderate relationship between neopterin and IFN-γ

Multivariate analysis of transcriptional changes following restoration of SERCA2a levels in failing rat hearts

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.Includes bibliographical references (leaves 126-129).We have identified the genes responsible for SERCA2a-induced reversal of heart failure, the leading cause of morbidity and mortality in the United States and developed countries. We have previously shown that restoration of a key enzyme that controls intracellular Ca2+ handling, the Sarcoplasmic Reticulum Ca2+ ATPase (SERCA2a), induces reversal of heart failure in humans and experimental models. We used high-density oligonucleotide arrays to explore the genetic reprogramming responsible for the reversal of heart failure upon adenoviral gene transfer of SERCA2a in a rat model of pressure overload hypertrophy in transition to heart failure. We combined model- and data-driven approaches to analyze the resulting multivariate microarray expression dataset corresponding to 4237 transcript sequences in six experimental groups. A multiscale systems approach was used that incorporated the main mechanisms underlying the control of gene expression at the transcriptional level, and the pathologic compensatory responses that occur in heart failure. The combinatorial control of gene expression that is thought to occur in mammals was implemented in a signal-processing model at the level of the heart cell nucleus; it identified 473 SERCA2a regulated genes. The integration of the main mechanisms underlying the pathologic compensatory responses that take place in heart failure was fundamental to the discovery of 10 functional transcriptional classes within this group of genes. In addition, 226 genes that were not targets of SERCA2a but were natural adaptive responses to aortic banding needed for clinical non-failure, were identified and functionally categorized. Biological functional distribution of SERCA2a targets revealed that SERCA2a activates genes(cont.) that function mainly in the cytoskeleton, ECM, Ca2+ signaling, signal transduction, cell cycle and growth and development pathways. The integration of model- and data-driven ideas was crucial to the elucidation of specific patterns in the multivariate data and allowed the discovery of novel genes and their potential role in the normalization of multiple pathways within the failing cell. This is a novel, powerful and portable method to elucidate multivariate genome-wide transcriptional networks from primary microarray data.by Adel B. Tabchy.S.M

Quaternary coastal uplift along the Talara Arc (Ecuador, Northern Peru) from new marine terrace data

Marine Geology, v. 228, n. 1-4, p. 73-91, 2006. http://dx.doi.org/10.1016/j.margeo.2006.01.004International audienceMarine terrace sequences have been investigated along the Talara Arc, a 1000-km-long stretch of the coast of Ecuador and northern Peru, characterized by subduction with a concave plan-view. Seven areas were investigated, evidencing flights of up to seven marine terraces with elevations reaching up to 360 m above mean sea level (amsl). Dating of the terraces was made using the Infra Red Stimulated Luminescence (IRSL) technique on sands as old as MIS 9 (∼330 ka). 14 C and U-series dates were obtained from fossil shells for geochronological cross control. Mean uplift rates along the Talara Arc range from about 0.10 up to 0.50 mm/ yr. The strongest uplift is observed in the Manta Peninsula of Ecuador in front of the subduction of the Carnegie Ridge. The uplift rate tends to slow down towards the northern and southern ends of the Talara Arc and then the transition toward the stable or subsiding coasts of central Peru and northern Ecuador and Colombia is sharp. The uplift appears to be homogeneous and related to 1) the map view curvature of the Arc, 2) the concave subduction pattern and 3) the Carnegie Ridge subduction

Relationship Between Organisational Trust and Decision - Making Participation

The purpose of this study is to evaluate the degree of trust among the Amman Education Directorates and how much educational supervisors participated in decision-making. The study sample is made up of 240 academic supervisors. The study’s findings showed that the Education Directorate appeared to have a moderate level of faith in organizational elements such management style, administrative policies, creative possibilities, and organizational values. Furthermore, the study revealed a significant relationship between organizational trust and the level of involvement in decision-making processes, with a significance level of (a≤0.5). However, no statistically significant variations in the sample members’ replies according to their gender, education, or experience were found. Based on these findings, the research recommends that educational directors give priority to strengthening supervisors’ organizational commitment to support educational policies that promote trust and provide them chances to apply their creative thinking to administrative tasks

COVID-19 disease severity and death in relation to vitamin D status among SARS-CoV-2-positive UAE residents

Insufficient blood levels of the neurohormone vitamin D are associated with increased risk of COVID-19 severity and mortality. Despite the global rollout of vaccinations and promising preliminary results, the focus remains on additional preventive measures to manage COVID-19. Results conflict on vitamin D’s plausible role in preventing and treating COVID-19. We examined the relation between vitamin D status and COVID-19 severity and mortality among the multiethnic population of the United Arab Emirates. Our observational study used data for 522 participants who tested positive for SARS-CoV-2 at one of the main hospitals in Abu Dhabi and Dubai. Only 464 of those patients were included for data analysis. Demographic and clinical data were retrospectively analyzed. Serum samples immediately drawn at the first hospital visit were used to measure serum 25-hydroxyvitamin D [25(OH)D] concentrations through automated electrochemiluminescence. Levels \u3c 12 ng/mL were significantly associated with higher risk of severe COVID-19 infection and of death. Age was the only other independent risk factor, whereas comorbidities and smoking did not contribute to the outcomes upon adjustment. Sex of patients was not an important predictor for severity or death. Our study is the first conducted in the UAE to measure 25(OH)D levels in SARS-CoV-2-positive patients and confirm the association of levels \u3c 12 ng/mL with COVID-19 severity and mortality