On Higher N-Derivation Of Prime Rings

The main purpose of this work is to introduce the concept of higher N-derivation and study this concept into 2-torsion free prime ring we proved that:Let R be a prime ring of char. 2, U be a Jordan ideal of R and be a higher N-derivation of R, then , for all u U , r R , n N

Make way for the algorithms: symbolic actions and change in a regime of knowing

When actors deem technological change undesirable, they may act symbolically by pretending to comply while avoiding real change. In our study of the introduction of an algorithmic technology in a sales organization, we found that such symbolic conformity led unintendedly to the full implementation of the suggested technological change. To explain this surprising outcome we advance a regime-of-knowing lens that helps to analyze deep challenges happening ‘under the surface’ during the process of technology introduction. A regime of knowing guides what is worth knowing, what actions matter to acquire this knowledge, and who has the authority to make decisions around those issues. We found that both the technologists who introduced the algorithmic technology, as well as the incumbent workers whose work was affected by the change, used symbolic actions to either defend the established regime of knowing or to advocate a radical change. While the incumbent workers enacted symbolic conformity by pretending to comply with suggested changes, the technologists performed symbolic advocacy by presenting a positive side of the technological change. Ironically, because the symbolic conformity enabled and was reinforced by symbolic advocacy, reinforcing cycles of symbolic actions yielded a radical change in the sales' regime of knowing: from one focused on a deep understanding of customers via personal contact and strong relationships, to one based upon model predictions from the processing of large datasets. We discuss the theoretical implications of these findings for the introduction of technology at work and for knowing in the workplace.Cambridge Judge Business School internal gran

A comparative case study: towards sustainable management of e-waste in the Kingdom of Saudi Arabia

Management of electrical and electronic waste (e-waste) becomes an increasing global concern because of rapid changing in technologies associated with tendency of people to keep up with the most recent technologies causing an increased volume rate of e-waste. This study compared and critically appraised three e-waste management models (producer responsibility, not producer responsibility, and sharing responsibility) currently applied in Malaysia and the United States of America (USA), in an attempt to explore best management practices that can be adopted in the Kingdom of Saudi Arabia. The data presented in this paper are secondary data derived from a wide range of authoritative sources. This study recommends the sharing responsibility model to effectively manage the growing rate of e-waste in the Kingdom of Saudi Arabia

Cytogenetic Estimation of Broccoli Extract on Dexamethasone Treated Mice

The current study was intended to evaluate the active compounds found in hydro-alcoholic extract of Brassica oleracea var. italica(broccoli), also to estimates the percentage of chromosomal aberrations (CAs) ,mitotic index (MI) and micronuclei (MN) formation in mouse bone marrow cells .The mice were divided into, negative group received (0.2 ml of  Distilled Water)intraperitoneally ,positive group I was given single dose of dexamethasone (0.4 mg/kg for 24 h) and positive group II (acute toxicity assay) administrated with (0.2 ml) of  high level dose (800 mg/kg) of extract for 5 days. Interaction groups treated with  different doses of extract (50,100,200,400 and 600 mg/kg) for 5 days in addition to a single ( 0.4 mg/kg) of dexamethasone per each dose of extract. High level dose (800mg/kg) of broccoli extract had show null genotoxicity for bone marrow cells of mouse. Dexamethasone showed significant effects (P< 0.05)  in reducing mitotic index and increased chromosomal aberrations and micronuclei  in mouse bone marrow cells (in vivo). Broccoli extract significantly increased MI and reduced (CA ,MN) (P< 0.05) especially at does (400 mg/kg). Keywords- mitotic index, Micronuclei formation ,Chromosomal aberrations , Dexamethasone, Brassica oleracea var. italica (broccoli), hydro-alcoholic extract

Impact of Foliar Selenium Feeding on Grain Selenium Content and Grain Yield of Wheat (Triticum aestivum)

Selenium (Se) is an essential micronutrient for living cell to be highly rich antioxidants, anti aging, anti cancer and many diseases. Also having an important effect on plant growth as a nutrient. Wheat is an important dietary source of organic selenium. Experiment in north Baghdad included six levels of Selenium Sulphate solution applied as a foliage feeding on wheat plant to increase grain Se content (Biofortification) and to improve grain yield .Results showed that grain selenium concentration increased to 4.5 mg per kg at the upper level (5mgm/L). Grain yield (ton/ha) showed a positive response, the yield was increased by 123% attributed to increasing of spikes per m2, 1000 grain weight and grain no. per spike. Biomass yield also showed a positive response to increased (se) solution concentration by doubled at the upper limit. Over all, these results encourage us to increase the upper limit of (Se) solution concentration to obtain the climax point

Studying the C–H crystals and mechanical properties of sustainable concrete containing recycled coarse aggregate with used nano-silica

The present study aims to replace 30%, 40%, and 50% of the natural coarse aggregate (NCA) of concrete with recycled coarse aggregate containing used nano-silica (RCA-UNS) to produce a new sustainable concrete. Three groups of concrete are made and their mechanical properties and microstructure are studied. In the first group, which was the control group, normal concrete was used. In the second group, 30%, 40%, and 50% of the NCA were replaced with coarse aggregate obtained from crushed concrete of the control samples and with 0.5% nano-silica as filler. In the third group, 30%, 40%, and 50% of the concrete samples’ NCA were replaced with aggregates obtained from 90-day crushed samples of the second group. Water absorption, fresh concrete slump, and compressive strength of the three groups were investigated and compared through scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) tests. The results show that the third group’s compressive strengths increased by 12.8%, 10.9%, and 10% with replacing 30%, 40%, and 50% of NAC with RCA-NS at 28 days compared to the control samples, respectively. This could be due to the secondary production of calcium silicate hydrate due to the presence of new cement paste. The third group’s microstructure was also improved due to the change in the C–H and the production of extra C–S–H. Therefore, the hydration of cement with water produces C–H crystals while reactions are induced by recycled aggregate containing used nano-silica

Numerical simulation of multi-tubes tank heat exchanger: toward an optimized configuration

Heat recovery is the reutilization of thermal energy lost by any industrial and resident ial application. Heat exchangers play a very effective role in recovering process. This paper deals with an optimization analysis of a suggested heat recovery heat exchanger. The suggested heat recovery heat exchanger is a multi-concentric tubes tank. This heat exchanger is designed to utilize thermal energy carried out by exhaust gases of a chimney to heat water for residential usage. The analysis is carried out numerically using a computational fluid dynamics “Comsol”software. Three configurations are considered, in which one tube, three tubes and six tubes systems are studied. The results show that in order to increase water temperature from 20°C to 70°C it requires 14 hours, 8 hours and 4 hours when using one tube, three tubes and six tubes system respectively. This makes six-tubed heat exchanger the best choice to heat the water quickly. However, one-tubed heat exchanger experiences the lowest corrosion phenomenon compared to other systems that makes one-tubed system to provide the longest lifetime

The crystal structure of Pneumolysin at 2.0 Å resolution reveals the molecular packing of the pre-pore complex

Pneumolysin is a cholesterol-dependent cytolysin (CDC) and virulence factor of Streptococcus pneumoniae. It kills cells by forming pores assembled from oligomeric rings in cholesterol-containing membranes. Cryo-EM has revealed the structures of the membrane-surface bound pre-pore and inserted-pore oligomers, however the molecular contacts that mediate these oligomers are unknown because high-resolution information is not available. Here we have determined the crystal structure of full-length pneumolysin at 1.98 Å resolution. In the structure, crystal contacts demonstrate the likely interactions that enable polymerisation on the cell membrane and the molecular packing of the pre-pore complex. The hemolytic activity is abrogated in mutants that disrupt these intermolecular contacts, highlighting their importance during pore formation. An additional crystal structure of the membrane-binding domain alone suggests that changes in the conformation of a tryptophan rich-loop at the base of the toxin promote monomer-monomer interactions upon membrane binding by creating new contacts. Notably, residues at the interface are conserved in other members of the CDC family, suggesting a common mechanism for pore and pre-pore assembly