2,110 research outputs found
Remote Sensing Satellites Planning System
A Remote Sensing Satellites Planning system (RSSP) for satellite constellations is responsible for managing these satellites by assigning the imaging tasks to each satellite in the constellation such that the loads are balanced and the resources are well used. The proposed system can be used with heterogeneous constellations that consist of satellites whose different specifications, different orbits' types and/or different payload types. This problem is a combinatorial optimization NP-hard problem modeled in this paper as a Constraint Satisfaction Problem using the Constraint Programming Technique. The output plan is obtained using one of three objective functions (gain maximization, area maximization, and image quality maximization) using four search algorithms (simulated annealing, hill climbing, tabu search and late acceptance) and different planning horizons (one track, one day and one month)
New Non-deterministic Approaches for Register Allocation
In this paper two algorithms for register allocation are presented. The first algorithm is a simulated annealing algorithm. The core of the algorithm is the Metropolis procedure. The algorithm presented in the paper has a linear time asymptotic complexity. The second algorithm is a genetic algorithm. The algorithm has a linear time complexity
Recurrence after correction of acquired ankle equinus deformity in children using Ilizarov technique
To describe our Ilizarov technique for the treatment of acquired equinus deformity in children and to determine if compliance with continuous use of an ankle foot orthosis (after removal of the fixator and until skeletal maturity) can influence the severity of recurrence. A cohort of 26 children with post-traumatic or post-burn contractures producing an equinus deformity was followed up for a minimum of 2 years after skeletal maturity. Cases with a bony deformity and/or nerve injury were excluded from this study. All patients were managed by a percutaneous tendo-Achilles lengthening followed by application of an Ilizarov external fixator. Post-operative treatment was in the form of gradual correction at a rate of 0.5 mm per day. Correction started from the second postoperative day until an over-correction of 15 degrees dorsiflexion was achieved. Ankle range of movement was encouraged 4 weeks prior to removal of the external fixator. On removal of the fixator, a posterior splint was applied until substituted by an ankle foot orthoses (AFO). The AFO was used continuously during the first 2–3 months and at nighttime thereafter until skeletal maturity. Fifteen children were compliant with the use of the AFO until skeletal maturity and 11 non-compliant. We compared the recurrence and the size of deformity between the two groups. The rate of recurrence, degree of equinus at recurrence and number of episodes of external fixation surgery showed statistical significant differences (P < 0.01) between the groups. The Ilizarov technique for treatment of acquired equinus deformity secondary to soft tissue scarring is a safe and effective technique. The use of an AFO until skeletal maturity can decrease the risk and degree of recurrence
Three Types of Traveling Wave Solutions for Nonlinear Evolution Equations Using the ( GǴ )− Expansion Method
Abstract: In the present paper, we construct the travelling wave solutions involving parameters of the (1+1) dimensional dispersive long wave equations, the (1+1)-dimensional Broer-Kaup system of equations and the variant Boussinesq equations by using a new approach, namely the ( GǴ )− expansion method, where G = G(ξ) satisfies a second order linear ordinary differential equation .When the parameters are taken special values, the solitary waves are derived from the travelling waves. The travelling waves solutions are expressed by hyperbolic, trigonometric and the rational functions. Keywords: the ( GǴ )-expansion method; traveling wave solutions, solitary wave solutions; Homogeneous balance; the (1+1) dimensional dispersive long wave equations; the (1+1)-dimensional Broer-Kaup equations; The variant Boussinesq equation
Selection of pomegranate (Punica granatum L.) in south-eastern Tunisia
Tunisia is one of the main producers and exporters of pomegranate (Punica granatum L.) in the world. Due to its international importance, the selection of both quantitative and qualitative most desirable varieties has become a necessity. To select new cultivars that are most appropriate for commercial use, 21 accessions were collected from different regions of south-east Tunisia. 24 morphological characters of the tree and fruit were studied for each accession. This study has revealed considerable diversity especially concerning the tree vigor, the fruit size and color and the acidity of juice. Taking into account all comments, some trees are considered particularly efficient in south-eastern Tunisia.Key words: South-east Tunisia, Punica granatum L., selection, morphological characters
The Impact of the Organizational Justice on the Development of the Organizational Citizenship Behavior in Jordanian Press Organizations
This study aimed to explore the impact of the organizational justice on the development of organizational citizenship behavior in the Jordanian press organizations. The population for the present study consists of all workers in Jordanian press organizations. This population includes 1835 employees. They are working across four press organizations, which are Jordan Press Foundation, the company of Jordan Press and Publishing, the Arab Printers Company, and the company of Jordan United Press and Publishing. 204 questionnaires were distributed to collect the necessary data and to test hypotheses of this study. The empirical results revealed that there was a significant statistical impact of the organizational justice (equity of distributions, fairness of procedures and fairness of transactions) on the organizational citizenship. The study recommended that the development of organizational citizenship strongly depended on the deploying of the organizational justice through: (a)the fairness of tasks and duties distribution through across organization, (b) commensurate these tasks and duties with employees’ abilities, (c) distribution of incentives depending on the merits of employees, (d) participation in decision making process supported the organizational citizenship and developed justice practices, (e) transparency through providing sufficient information and discussing work-related decisions found for the organizational justice and then deployed the organizational citizenship. Key words: organizational justice, organizational citizenship behavior, Jordan Press Organizations
PHYTOCHEMICAL STUDY OF BIOACTIVE CONSTITUENTS FROM SATUREJA MONTANA L. GROWING IN EGYPT AND THEIR ANTIMICROBIAL AND ANTIOXIDANT ACTIVITIES
 Objective: This work aimed to investigate the lipid constituents and flavonoidal compounds of Satureja montana, in addition to evaluation of different extracts and/or isolated compounds as antimicrobials and antioxidants.Methods: The volatile and lipid constituents were extracted with n-hexane by partition from hydroalcoholic extract of S. montana L. aerial parts, after then were fractionated to unsaponifiable matters and fatty acid methyl esters which were identified by gas–liquid chromatography and/or gas chromatography–mass spectrometry. The phenolic constituents were isolated from the ethyl acetate fraction of the aqueous methanolic extract of the aerial parts of the plant. The antimicrobial activity of different extracts and the isolated compounds was evaluated against Gram-positive, Gram-negative bacteria, yeast, and fungus using a modified Kirby-Bauer disc diffusion method.Results: The identified compounds are luteolin-7-rhamnoside-4'-O-β-glucopyranoside (1), quercetin-3-O-α-L-rhamnopyranoside (2), quercetin- 7-O-glucopyranoside (3), luteolin-7-O-glucopyranoside (4), 5-hydroxy-6,7,8,4'-tetramethoxy flavone (5), gallic acid (6), 2,3-hexahydroxydiphenoyl 1-galloyl glucopyranoside (7), and quercetin (8). The structure of all isolated compounds was established using different chromatographic and spectroscopic measurements (PC, thin-layer chromatography, ultraviolet [UV], 1D, 2D-nuclear magnetic resonance, and MS). Compound-2 showed the highest antibacterial activity against all the tested microorganisms. Hydroalcoholic extract exhibited high antioxidant activity (87.7%). On the other hand, hexane fraction showed a low antioxidant activity (46.4%), in addition to the compound-8 showed the highest antioxidant activity (96.27%) in 2,2-diphenyl-1-picrylhydrazyl assay.Conclusion: It can be concluded that the hydroalcoholic extract of S. montana showed significant antimicrobial and antioxidant activity
What doesn't kill you makes you stranger: Dipeptidyl peptidase-4 (CD26) proteolysis differentially modulates the activity of many peptide hormones and cytokines generating novel cryptic bioactive ligands
Dipeptidyl peptidase 4 (DPP4) is an exopeptidase found either on cell surfaces where it is highly regulated in terms of its expression and surface availability (CD26) or in a free/circulating soluble constitutively available and intrinsically active form. It is responsible for proteolytic cleavage of many peptide substrates. In this review we discuss the idea that DPP4-cleaved peptides are not necessarily inactivated, but rather can possess either a modified receptor selectivity, modified bioactivity, new antagonistic activity, or even a novel activity relative to the intact parent ligand.
We examine in detail five different major DPP4 substrates: glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), peptide tyrosine-tyrosine (PYY), and neuropeptide Y (NPY), and stromal derived factor 1 (SDF-1 aka CXCL12). We note that discussion of the cleaved forms of these five peptides are underrepresented in the research literature, and are both poorly investigated and poorly understood, representing a serious research literature gap. We believe they are understudied and misinterpreted as inactive due to several factors. This includes lack of accurate and specific quantification methods, sample collection techniques that are inherently inaccurate and inappropriate, and a general perception that DPP4 cleavage inactivates its ligand substrates.
Increasing evidence points towards many DPP4-cleaved ligands having their own bioactivity. For example, GLP-1 can work through a different receptor than GLP-1R, DPP4-cleaved GIP can function as a GIP receptor antagonist at high doses, and DPP4-cleaved PYY, NPY, and CXCL12 can have different receptor selectivity, or can bind novel, previously unrecognized receptors to their intact ligands, resulting in altered signaling and functionality. We believe that more rigorous research in this area could lead to a better understanding of DPP4’s role and the biological importance of the generation of novel cryptic ligands. This will also significantly impact our understanding of the clinical effects and side effects of DPP4-inhibitors as a class of anti-diabetic drugs that potentially have an expanding clinical relevance. This will be specifically relevant in targeting DPP4 substrate ligands involved in a variety of other major clinical acute and chronic injury/disease areas including inflammation, immunology, cardiology, stroke, musculoskeletal disease and injury, as well as cancer biology and tissue maintenance in aging
Aging changes of the testis in albino rat: light, electron microscopic, morphometric, immunohistochemical and biochemical study
Background: Aging has a deleterious effect on the morphology of the male reproductive system which might, in turn, lead to changes in spermatogenesis and consequently, decrease in both quality and quantity of spermatozoa.
Materials and methods: The present study elucidated the histological and ultrastructural changes of testes of adult albino rats during aging and applied morphometric measures to obtain quantitative data for these changes. The oxidative and antioxidative markers of aged testes were also assessed.
Results: The results documented the presence of age-related regressive structural changes of the testis accompanied with an increase in the apoptosis and a decrease in the proliferative capacity.
Conclusions: The biochemical results gave evidence of an imbalance between the oxidative damage and the antioxidant defence indicating increased oxidative stress of aged testis
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