A Virtual Infrastructure for Mitigating Typical Challenges in Sensor Networks

Sensor networks have their own distinguishing characteristics that set them apart from other types of networks. Typically, the sensors are deployed in large numbers and in random fashion and the resulting sensor network is expected to self-organize in support of the mission for which it was deployed. Because of the random deployment of sensors that are often scattered from an overflying aircraft, the resulting network is not easy to manage since the sensors do not know their location, do not know how to aggregate their sensory data and where and how to route the aggregated data. The limited energy budget available to sensors makes things much worse. To save their energy, sensors have to sleep and wake up asynchronously. However, while promoting energy awareness, these actions continually change the underlying network topology and make the basic network protocols more complex. Several techniques have been proposed in different areas of sensor networks. Most of these techniques attempt to solve one problem in isolation from the others, hence protocol designers have to face the same common challenges again and again. This, in turn, has a direct impact on the complexity of the proposed protocols and on energy consumption. Instead of using this approach we propose to construct a lightweight backbone that can help mitigate many of the typical challenges in sensor networks and allow the development of simpler network protocols. Our backbone construction protocol starts by tiling the area around each sink using identical regular hexagons. After that, the closest sensor to the center of each of these hexagons is determined—we refer to these sensors as backbone sensors. We define a ternary coordinate system to refer to hexagons. The resulting system provides a complete set of communication paths that can be used by any geographic routing technique to simplify data communication across the network. We show how the constructed backbone can help mitigate many of the typical challenges inherent to sensor networks. In addition to sensor localization, the network backbone provides an implicit clustering mechanism in which each hexagon represents a cluster mud the backbone sensor around its center represents the cluster head. As cluster heads, backbone sensors can be used to coordinate task assignment, workforce selection, and data aggregation for different sensing tasks. They also can be used to locally synchronize and adjust the duty cycle of non-backbone sensors in their neighborhood. Finally, we propose “Backbone Switching”, a technique that creates alternative backbones and periodically switches between them in order to balance energy consumption among sensors by distributing the additional load of being part of the backbone over larger number of sensors

Effect of Gamma Irradiation on Wheat Immature Culture Regenerated Plants

Abstract: The effect of gamma rays on grains of wheat (Triticum aestivum L.) irradiated with 150, 250, 350 and 450 Gy was studied on second generation (M 2 ) plants immature embryos culture callus growth rate, plant regeneration, agronomic traits and phenotypic and genotypic coefficients of four wheat cultivars. The results showed a highly significant effect between the four tested wheat cultivars i.e. Sids-1, Sakha-93, Sahel-1 and Giza-168 under different doses of gamma rays. The low dose of 150 Gy seemed to have a stimulating effect on all characters studied. On the other hand, the high doses caused significant reduction as compared to the control for all studied traits. The highest percentage of callus growth rate and plant height was obtained in Sakha-93. The interaction between gamma rays at 150 Gy and Sids-1 give a significant increase in callus induction percentage, plant regeneration, all growth characters, yield and its component as compared to control. Genotypic and phenotypes correlation were positive and highly significant between callus growth rate and grain yield per plant

Application of LANDSAT satellite imagery for iron ore prospecting in the western desert of Egypt

The author has identified the following significant results. The delineation of the geological units and geological structures through image interpretation, corroborated by field observations and structural analysis, led to the discovery of new iron ore deposits. A new locality for iron ore deposition, namely Gebel Qalamun, was discovered, as well as new occurrences within the already known iron ore region of Bahariya Oasis

Comparative experimental study on two designed intravenous anaesthetic combinations in dogs

The goal of the present study is to design a good anaesthetic program for dogs which can lead to optimal anaesthesia with no or minimal post-operative adverse effects. For this purpose, we designed two naesthetic combinations and compared their effects in Mongrel dogs: combination ‘A’ consisting of atropine, xylazine, ketamine plus propofol, and combination ‘B’ consisting of atropine, diazepam, ketamine plus propofol. The onset and duration of anaesthesia induction, the duration of maintenance as well as the period of recovery were recorded and compared for both combinations. Furthermore, heart rate, respiratory rate, body temperature as well as blood picture were analyzed before and after administration of the proposed anaesthetic regimens. Administration of combination ‘A’ lead to rapid onset, within seconds, and induction of anaesthesia. The anaesthetic effect was maintained for approximately 29 minutes after injection of propofol. This was followed by very smooth recovery within approximately 68 minutes after induction of anaesthesia. In contrast, a less efficient induction and maintenance of anaesthesia as well as individual variability was observed after administration of combination ‘B’. Approximately 14 minutes were needed for anaesthesia induction, which was maintained for 23 minutes after injection of propofol. Furthermore, administration of combination ‘B’ was associated with alterations in heart rate, body temperature and hematological picture. In conclusion, our results revealed that combined administration of atropine, xylazine, ketamine plus propofol (combination ‘A’) is considered satisfactory for anaesthesia in dogs with minimal postoperative side effects

Regional prospecting for iron ores in Bahariya Oasis-El Faiyum area, Egypt, using LANDSAT satellite images, part 1

There are no author-identified significant results in this report

Geologic interpretation of LANDSAT satellite images for the Qattara Depression area, Egypt

The author has identified the following significant results. For the first time the regional geological units are given. Faults, fractures, and folds are included, as well as drainage lines which help to visualize the environmental impact of the Qattara project for electric power generation and to assess the regional questions involved in its implementation

Micro/nano-structural evolution in spruce wood during soda pulping

Alkaline delignification of wood tissue is the core of the global pulping technology and the most prominent large-scale separation of the main wood components. This work aims at improved understanding of the interplay between the topochemistry of alkaline pulping and the associated morphological changes. Morphology and chemical structure of partially soda-delignified wood chips were studied combining X-ray tomography (XRT), X-ray diffraction analysis and compositional characterization (lignin and carbohydrate content). The XRT studies of wet samples (providing 3D structural information without interfering drying effects), allowed observation of the cell wall separation as an increasing amount of lignin was removed with the increasing pulping time. Comparison between the microstructure of the surface and the central parts of the treated chips showed a more delignified microstructure at the surface, which highlights the dependence of the delignification process on the mass transport (hydroxide ions and lignin fragments) through the wood tissue. The crystallite size of cellulose increased in the <200> crystal planes during the early stage of pulping while there was little effect on the <110> plane

Association of polymorphisms of two histamine-metabolizing enzymes with allergic asthma in Egyptian children

Background: Histamine released from mast cells and basophils plays a key role in the development of allergic diseases such as allergic asthma, rhinitis or anaphylaxis. Histamine-metabolizing enzymes: N-methyltransferase (HNMT) and amiloride binding protein 1(ABP) are involved in allergic inflammation.Objective: This study was undertaken to evaluate the relationship between polymorphisms of two genes encoding the histamine metabolizing enzymes HNMT and ABP1 with the development of allergic asthma in Egyptian children.Methods: This is a case control study performed on 100 atopic asthmatic and 94 healthy control children. Conventional method of PCR amplification was used for genotyping.Results: Distribution of HNMT -105 Thr → Ile (-314 C to T) single nucleotide polymorphism (SNP) genotypes and Thr and Ile (C and T) alleles among patients and controls revealed significant increase in the frequencies of Thr / Ile (CT) and Thr / Ile (CT) + Ile / Ile (TT) in atopic asthmatics than in controls (p= 0.04 and 0.002 respectively). There was also a significant increase in Ile (T) alleles in atopic asthmatic patients than controls (p= 0.002). The 2029 CG SNP polymorphism of ABP1gene was significantly associated with atopic asthma (p=0.0003).Conclusion: The results of this study suggest that genetic variations in the histaminemetabolizing enzyme (HNMT and ABP1) genes might contribute to the pathogenesis of asthma in the studied children.Keywords: Amiloride binding protein, asthma, atopy, children, Nmethyltransferas

Radiation effect on viscous flow of a nanofluid and heat transfer over a nonlinearly stretching sheet

In this work, we study the flow and heat transfer characteristics of a viscous nanofluid over a nonlinearly stretching sheet in the presence of thermal radiation, included in the energy equation, and variable wall temperature. A similarity transformation was used to transform the governing partial differential equations to a system of nonlinear ordinary differential equations. An efficient numerical shooting technique with a fourth-order Runge-Kutta scheme was used to obtain the solution of the boundary value problem. The variations of dimensionless surface temperature, as well as flow and heat-transfer characteristics with the governing dimensionless parameters of the problem, which include the nanoparticle volume fraction ϕ, the nonlinearly stretching sheet parameter n, the thermal radiation parameter NR, and the viscous dissipation parameter Ec, were graphed and tabulated. Excellent validation of the present numerical results has been achieved with the earlier nonlinearly stretching sheet problem of Cortell for local Nusselt number without taking the effect of nanoparticles

Građa i optička svojstva tankih polikristaliničnih slojeva CuGaxIn1−xSe2

Structural and optical properties of CuGaxIn1−xSe2 (0 ≤ x ≤ 0.75) polycrystalline thin films deposited by vacuum evaporation were studied as a function of composition. The optical absorption spectra of CuGaxIn1−xSe2 thin films (x /=0) show four energy gaps (Eg1 , Eg2 , Eg3 and Eg4 ) which are attributed to the fundamental edge, band splitting by crystal-field and spin-orbit splitting, and to transitions originating from copper 3d levels, respectively. The primary transition energies exhibit bowing behaviour expressed by the relationship Eg1 (x) = 1.011 + 0.448x + 0.186x 2 . The second and third transition energies are higher than the primary transition energies by 0.10–0.11 eV and 0.18–0.185 eV, respectively. The effect of thermal treatment on the values of energy gaps is discussed in terms of the structure of the films. The primary transition energies of annealed CuGaxIn1−xSe2 can be fitted by the parabolic form Eg1 (x) = 1.04 + 0.46x + 0.22x 2 .Proučavali smo strukturna i optička svojstva tankih polikristaliničnih slojeva CuGaxIn1−xSe2, isparenih u vakuumu, u ovisnosti o sastavu (0 ≤ x ≤ 0.75). Optički apsorpcijski spektri tankih slojeva CuGaxIn1−xSe2, (x /=0), pokazuju četiri energijska procijepa (Eg1 , Eg2 , Eg3 i Eg4 ) koji se pridjeljuju osnovnom rubu, cijepanju vrpci kristalnim poljem i cijepanju spin-staza, odnosno prijelazima iz 3d stanja bakra. Prvotni prijelazi pokazuju kvadratnu ovisnost koju izražavamo relacijom Eg1 (x) = 1.011 + 0.448x + 0.186x 2 . Druga i treća prijelazna energija su (0.10 − 0.11 eV) odnosno (0.18 − 0.185 eV) više od primarne prijelazne energije. Pomoću građe slojeva objašnjavamo učinak toplinske obrade na vrijednosti energijskih procijepa. Prvotne prijelazne energije opuštenog CuGaxIn1−xSe2 mogu se predstaviti kvadratnim izrazom Eg1 (x) = 1.04 + 0.46x + 0.22x 2