624 research outputs found

    Changing economy of semi-settled Bedouins

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    MANAGEMENT’S PERCEPTION OF STOCK DIVIDEND DISTRIBUTION IN AN EMERGING CAPITAL MARKET: THE CASE OF KUWAIT

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    The purpose of this study is to investigate perceptions of top managers of Kuwaiti companies regarding factors the affect their companies’ decision to distribute stock dividend ( SD ). A questionnaire listing 32 reasons that could explain companies’ decisions to declare SDs was distributed to a sample of 120 randomly selected top managers from 100 Kuwaiti companies and 73 responses were received (representing a 61% response rate ). Participants were classified according to: ( 1 )business sector ( investment, real estate, banking, service, and industrial ) and ( 2 ) size of SDs ( small ( less than 25% ) and large ( 25% or more )). Nonparametric statistical tests were employed to analyze the data.Stock Dividends, Importance Ratings, Trading Liquidity, Institutional Investors

    Review of Gamow-Teller and Fermi Transition Strength Functions

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    We studied the temperature effect in isospin-singlet pairings in Gamow-Teller excitations. We use theories of a hole-particle in the mean field shell model studied decay transition using the one-particle-one-hole model for the β\beta-decay of odd-even isotopes and the two-particle-hole models for the β\beta-decay of even-even and/or odd-odd isotopes. Our reference isotopes for the one-particle-one-hole model are \ce{^{15}O}, \ce{^{15}N}, \ce{^{17}F}, and \ce{^{41}Sc}, whereas for the two-particle-hole model we use \ce{^{16}N} (for β\beta^--decay) and \ce{^{56}Ni} and \ce{^{40}Sc} (for β+\beta^+/EC). The calculations involve evaluating the matrix elements of Gamow -Teller and Fermi transitions, then calculate the reduced transition probabilities of Gamow-Teller and Fermi, from which we evaluate the half-lives and the strength function ftft. The results are compared with the available experimental data. For one-particle-one-hole model we found there is a deviation from experimental values which indicates that the model is not valid for beta decay for the even-even nuclei in the ground state due to the residual nucleon-nucleon interaction. As for a two-particle-hole model, we calculated the transition amplitude, from which we calculated the strength of the transition logft\log ft values. We found an excellent agreement between experimental and theoretical results. By drawing the relationship between temperature versus logft\log ft values, we found the general trend is that the strength function values slowly decrease as temperatures increases. There are fluctuations logft\log ft due to the strongly dependent of logft\log ft on the shell configuration of the valence nucleons.Comment: 40 pages, 11 figure

    Effects of Faulty Design Phase on School Buildings Maintenance in Gaza Strip

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    The aim of this paper is to identify and rank the design phase faults/errors affecting on the maintenance of the United Nations Relief and Works Agency (UNRWA)'s school’s buildings in Gaza Strip, and to propose recommendations for minimizing the future maintenance problem related to the school buildings at Gaza Strip. A survey was conducted to collect the required data were adopted in this study. This study reveals the important factors that leading to defects in the design stage which includes: lack of workshops to discuss construction problems between project parts, Inadequate QA/QC programs during design stage, Lack of auditing and archiving of approved as-built drawing documents electronically after the completion the project. The study recommends several actions to improve maintenance performance of UNRWA's schools in Gaza Strip. The designer must take into account maintenance considerations during the design and supervision stages by choosing of durable materials. The UNRWA should conduct workshops or training courses for designers, supervisor, and maintenance engineers

    Replay Attacks and Defenses Against Cross-shard Consensus in Sharded Distributed Ledgers

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    We present a family of replay attacks against sharded distributed ledgers targeting cross-shard consensus protocols, such as the recently proposed Chainspace and Omniledger. They allow an attacker, with network access only, to double-spend or lock resources with minimal efforts. The attacker can act independently without colluding with any nodes, and succeed even if all nodes are honest; most of the attacks can also exhibit themselves as faults under periods of asynchrony. These attacks are effective against both shard-led and client-led cross-shard consensus approaches. We present Byzcuit-a new cross-shard consensus protocol that is immune to those attacks. We implement a prototype of Byzcuit and evaluate it on a real cloud-based testbed, showing that our defenses impact performance minimally, and overall performance surpasses previous works

    The effect of radiotherapy on survival of dental implants in head and neck cancer patients

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    Objectives: To explore the current literature of the survival of dental implants in irradiated head and neck cancer patients considering the role of implant location, bone augmentation, dose of radiation and timing of implant placement. Study Design: Pubmed search was conducted to identify articles published between January 2000 and December 2014 and presenting data of dental implant survival with radiotherapy in head and neck cancer patients. Studies on animal subjects and craniofacial implants were excluded. Results: 18 articles out of 27 were eligible for inclusion in this systematic review. 12 out of 18 studies reported favorable outcome of dental implants and radiotherapy with survival rates between 74.4% and 97%. Seven out of ten studies comparing the survival rates according to site of implant placement reported that implants were found to osseointegrate with greater success in the irradiated mandible than irradiated maxilla. 5 studies which compared implant survival in irradiated native bone versus irradiated grafted bone reported that irradiated grafted bone showed a significantly reduced dental implant survival rate in comparison to irradiated native bone. 6 out of 18studies in which radiation doses exceeded 70 Gy reported lower survival rates of dental implants in comparison to the studies in which radiation doses were ≤70Gy. Higher survival rates were reported in 2 studies in which implants placement was before radiotherapy in comparison to the remaining 16 studies in which implants placement was after radiotherapy. Conclusions: Dental implants may be affected by radiotherapy especially when they are placed in maxilla, in grafted bone, or after radiation, however, they remain a functional option for rehabilitation of head and cancer patients. More prospective cohort studies and randomized controlled trails are still needed to draw more evidence based conclusion

    Synthesis and thermodynamics of the reactions of [Pd(Eten)(H2O)2]2+ with ligands of biological significane with reference to the antitumour activity

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    Pd(Eten)Cl2  complex, where Eten = N-ethylethylenediamine , was synthesized and characterized by elemental analysis and spectroscopic techniques. The stoichiometry and stability of the complexes formed between [Pd(Eten)(H2O)2]2+ and various biologically relevant ligands  as adenine, adenosine, adenosine-5’-monophosphate  and some selected peptides  were investigated at 25ºC and 0.1 M ionic strength. The speciation diagrams of the complexes formed in solutions are evaluated. Thermodynamic parameters for Pd(Eten)-glycylglycine complexes were estimated

    Industrial Investment in Ma'an Governorate, Obstacles, Opportunities and Successful Projects

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    Industrial investment is one of the most important factors that help achieving sustainable economic development. This study aims to explore the obstacles, which constrain industrial investments in Ma'an Governorate (located in south Jordan) and the incentives to promote these investments. It also aims to explore investment projects with successful future opportunities. A survey on government and private departments’ managers, individual entrepreneurs, and professionals in Ma’an Governorate was conducted for data collection. A total of 300 questionnaires were distributed. Out of this number, only 186 were returned. The response rate was about 58%. One-sample t-test and descriptive statistics showed that there are obstacles facing industrial investments, on the other side it showed that there are real incentives for industrial investments. The research findings show that the Governorate of Ma'an is eligible to attract various industrial projects, which have opportunities to be highly successful in the future such as glass factories, plastics, marble, clothing, and construction materials industries. This study recommends Jordanian government to improve basic infrastructure, promote private industrial investments and exploit the opportunities in the area through directing industrial investments towards the available resources. It also recommends promoting the governorate of Ma'an through media and highlights the prospects of success in various fields of industrial investment in a positive way. Keywords: Industrial Investment, investment obstacles, investment opportunities, future investment projects, Ma’an Governorate

    Charging infrastructure for commercial electric vehicles: Challenges and future works

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    The journey towards transportation electrification started with small electric vehicles (i.e., electric cars), which have enjoyed an increasing level of global interest in recent years. Electrification of commercial vehicles (e.g., trucks) seems to be a natural progression of this journey, and many commercial vehicle manufacturers have shifted their focus on medium- and heavy-duty vehicle electrification over the last few years. In this paper, we present a comprehensive review and analysis of the existing works presented in the literature on commercial vehicle charging. The paper starts with a brief discussion on the significance of commercial vehicle electrification, especially heavy- and medium-duty vehicles. The paper then reviews two major charging strategies for commercial vehicles, namely the return-to-base model and the on route charging model. Research challenges related to the return-to-base model are then analysed in detail. Next, different methods to charge commercial vehicles on route during their driving cycles are summarized. The paper then analyzes the challenging issues related to charging commercial vehicles at public charging stations. Future works relevant to these challenges are highlighted. Finally, the possibility of accommodating vehicle to grid technology for commercial vehicles is discussed
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