798 research outputs found

    Self-interference cancellation in underwater acoustic communications systems using orthogonal pilots in IBFD

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    This paper proposes a Self-interference (SI) cancellation system model of Underwater acoustic (UWA) communication for in-band full-duplex (IBFD) technology. The SI channel is separated from the Far channel by exploiting a concurrently orthogonal pilot channel estimation technique using two orthogonal frequency-division multiplexing (OFDM) blocks to establish orthogonality between them based on a unitary matrix. Compared to the half-duplex channel estimator, the mean squared error (MSE) and the bit error rate (BER) provided strong evidence for the efficiency of the proposed SI cancellation. Since full-duplex systems are more efficient than half-duplex ones, the proposed approach might be seen as a viable option for them. The proposed method proved effective when used with a fixed full-duplex (FD) position and FD shifting of up to 4°. Different channel lengths and distances are adopted to evaluate the proposed method. Initial findings indicate that MSE for the SI channel minimum mean-square error (MMSE) estimator at 20 dB is 0.118 · 10−3, for fixed FD. In addition, this paper presents a geometry channel model for the Far channel in the IBFD underwater communication system that describes the propagation delay of the multipath reflection. The simulation results for the multipath propagation delay spread are similar to the traditional results, with the delay spread of the suggested model reaching (79 ms), which is close to the Bellhop simulator result (78 ms)

    Évaluation de la sensibilitĂ© de sept clones de palmier Ă  huile (Elaeis guineensis Jacq.) Ă  Coelaenomenodera lameensis Berti et Mariau (Coleoptera, Chrysomelidae) Konan J.

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    Objectifs : Évaluer la sensibilitĂ© de 7 clones d’Elaeis guineensis Ă  Coelaenomenodera lameensis (Coleoptera : Hispinae) et estimer les dĂ©gĂąts occasionnĂ©s par l’insecte au terme d’un cycle de dĂ©veloppement complet sur chaque type de matĂ©riel clonal.MĂ©thodologies et RĂ©sultats : des insectes adultes de C. lameensis ont Ă©tĂ© transposĂ©s sur des folioles de clones d’Elaeis guineensis isolĂ©s dans des manchons. L’évolution des insectes a Ă©tĂ© ensuite observĂ©e à chaque Ă©tape du cycle normal de dĂ©veloppement de C. lameensis. Les dĂ©gĂąts provoquĂ©s par l’insecte ont étĂ© estimĂ©s par le rapport entre la surface de foliole attaquĂ©e et la surface totale de foliole. Les rĂ©sultats ont montrĂ© que certains clones Ă©taient moins favorables au dĂ©veloppement de l’insecte que d’autres. Le clone LMC247, avec 53,80 % ± 2,56 de surface foliaire attaquĂ©e, a Ă©tĂ© plus sensible Ă  l’insecte que les autres clones LMC159, LMC161, LMC022, LMC010, LMC270 et LMC291 oĂč les dĂ©gĂąts observĂ©s ont Ă©té en dessous de 25%..Conclusion et Application : au regard des rĂ©sultats, il ressort que le dĂ©veloppement de C. lameensis est influencĂ© par le type de matĂ©riel clonal. Les dĂ©gĂąts sur les clones testĂ©s ont Ă©tĂ© gĂ©nĂ©ralement de faible intensitĂ©. Cette approche expĂ©rimentale, laisse prĂ©sager de bonnes perspectives pour la lutte gĂ©nĂ©tique contre C. lameensis.. En effet, plus de 300 clones de palmier ont dĂ©jĂ  Ă©tĂ© crĂ©es en CĂŽte d’Ivoire. Un criblage Ă©largi Ă  l’ensemble de ce matĂ©riel va permettre d’identifier Ă  terme des clones performants pour contrĂŽler le ravageur, au regard de l’homogĂ©nĂ©itĂ© de ce type de matĂ©riel vĂ©gĂ©tal.Mots clĂ©s : clone, palmier Ă  huile, lutte gĂ©nĂ©tique, CoelĂŠnomenodera lameensisEvaluation of seven oil palm clones (Elaeis guineensis Jacq.) sensibility to Coelaenomenodera lameensis Berti and Mariau (Coleoptera, Chrysomelidae)Objective: this study aims to evaluate seven oil palm clones sensibility to Coelaenomenodera lameensis (Coleoptera: Hispinae) and to estimate the damage caused by this insect on each type of clonal material.Methods and results: adult insects of C. lameensis were transposed on Elaeis guineensis clones leaflets isolated in canvas bags. Insect evolution was observed at each stage of normal development cycle of C. lameensis. The damage caused by the insect was estimated using the ratio of the surface of leaflet attacked and the total surface of leaflet. The results showed that some clones were less favorable to the development of C. lameensis than others. The clone LMC247, with 53.80 ± 2.56% of leaf surface attacked was more susceptible to C. lameensis than the other clones LMC159, LMC161, LMC022, LMC010, LMC270 and LMC291. For these clones, the damages noted were below 25% of leaf area attacked.Conclusion and application: the results showed that C. lameensis development depended of the clones. Overall, a low intensity of damage was observed on the leaflet of the clones. This experimental approach suggests good projection for genetic control of C. lameensis with oil palm clone material. Indeed, more than 300 oil palm clones have already been established in CĂŽte d'Ivoire. The screening of this material can help selecting performing material to control the pest due to the homogeneity of this type of plant material. Key words: clone, oil palm, genetic control, CoelĂŠnomenodera lameensi

    Permanent Maxillary and Mandibular Incisors

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    The permanent incisors are the front teeth that erupt between 6 and 8 years of age. They are eight in number, four upper and four lower, two centrals and two laterals. They have sharp biting surfaces designed for shearing and cutting of food materials into small chewable pieces. They are the teeth most visible to the others during eating, smiling and talking, and thus, they have high aesthetic value for the individuals. The unique characteristics, arch position, function, development and chronological age of each tooth will be highlighted. In addition, the different aspects with their geometric outlines, outlines and surface anatomy of these teeth will be described. A brief explanation about the pulp cavity, tooth socket and normal occlusion for each tooth will be included

    Chemical compositions and heavy metal contents of Oreochromis niloticus from the main irrigated canals (rayahs) of Nile Delta

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    AbstractThe present study aimed to assess the seasonal variations of the proximate chemical composition, physicochemical, microbiological aspects and heavy metal concentrations of Oreochromis niloticus muscles collected from The Nile rayahs from spring 2014 to winter 2015. Rayahs are the main irrigated canals of Nile Delta, Egypt and represent El Tawfiki, El Menoufy, El Behery, and El Nasery rayahs. Results showed a spatial and temporal significant difference (p<0.01) in the proximate composition and Physicochemical aspects of O. niloticus muscles. The moisture, protein, fat, ash, carbohydrates and calorific values varied between (78.55–80.77%), (16.10–17.88%), (1.10–1.95%), (0.55–1.50%), (0.10–0.94%) and (78.37–89.73%), respectively. Heavy metal accumulation in the O. niloticus muscles showed irregular distributions with descending order of: Fe>Zn>Mn>Cu>Pb>Cd. Generally, heavy metals, TVB-N, TMA, TBA and TVC did not exceed the maximum permissible limits in the tissues of O. niloticus. The values of Hazard Index (HI) and Hazard Quotient (HQ) are lower than the acceptable limits, which indicate that the metals in O. niloticus in the Nile rayahs, Egypt, do not pose any particular human health risk concern. Therefore, O. niloticus muscles collected from four rayahs are safe for human consumption and could be used as a source of healthy diet for humans

    Amine-functionalized MCM-48 as Adsorbent of Zn2+ and Ni2+ Ions

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    A compound, 3-aminopropyltrimetoxy silane, has been used to modify mesoporous silica, MCM-48. The modified silica (NH2-MCM-48) was utilized to remove Zn2+ and Ni2+ ions from solutions. The mesoporous material was synthesized in the alkaline solution. Characterization of the unmodified materials was conducted by X-ray diffraction and FT-IR spectroscopy. The ions adsorbed on NH2-MCM-48 were studied at various pHs, contact times and initial ions concentrations. An Atomic Absorption Spectrophotometer (AAS) measured the ions content in the solution.. Pseudo-first-order and pseudo-second-order models performed the kinetic adsorption. The adsorption isotherm was examined by Langmuir and Freundlich isotherms. The result found that optimum contact time for the adsorption of Zn2+ ion was lower than that for Ni2+ ion. The adsorption followed the pseudo-second-order model with the adsorption rate of 4.56x10-2 g mg-1 min-1 for Zn2+ ion and 7x10-4 g mg-1 min-1 for Ni2+ ion. The optimum pH was 6 and 4 for Zn2+ and Ni2+ adsorption, respectively. The uptake of both ions from solutions by NH2-MCM-48 fixed better the Langmuir than the Freundlich model with the adsorption capacity of 0.55 and 0.43 mmol g-1, correspondingly. This research work provides valuable information on the interaction between the ions and the functional group of adsorbent

    Predictive models for COVID-19 detection using routine blood tests and machine learning

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    The problem of accurate, fast, and inexpensive COVID-19 tests has been urgent till now. Standard COVID-19 tests need high-cost reagents and specialized laboratories with high safety requirements, are time-consuming. Data of routine blood tests as a base of SARS-CoV-2 invasion detection allows using the most practical medicine facilities. But blood tests give general information about a patient’s state, which is not directly associated with COVID-19. COVID-19-specific features should be selected from the list of standard blood characteristics, and decision-making software based on appropriate clinical data should be created. This review describes the abilities to develop predictive models for COVID-19 detection using routine blood tests and machine learning

    Cell-mediated immunity in recent-onset type 1 diabetic children

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    Background: The ability to suppress an immune response makes regulatory T-cells (T-reg) an attractive candidate as a novel therapeutic agent for treating autoimmune diseases. The mechanisms involved in maintenance of peripheral tolerance include a specialized subset of regulatory-T-cells (Treg) within the T-cell population. The CD4+ CD25+ T-cells may be important in modulating the risk for autoimmunity. Auto-reactive cytotoxic T-cells recognize peptide epitopes displayed on the beta cells surface in the context of HLA class1 molecules. A population of CD8+ regulatory T-cells characterized by expression of CD25 and FOXP3 have been identified and induced in the human peripheral blood cells. The regulatory activity of these cells is on autologous, antigen-reactive CD4+ T-cells in a cell contactdependent manner. These findings provide an evidence for a new mechanism for induction of immune regulation in human. Objective: This study was aiming to assess the cellular immune parameters including the percentage of CD4+, CD8+, CD4+/CD8+ ratio,CD4+CD25+, CD8+ CD25+ lymphocytes, which may have its application in developing immune therapy based tools for halting disease progression. Methods: This study was conducted on 20 children of recent onset type 1 diabetes (disease duration 0.05) between the two groups. A significant inverse correlation was found between CD4+ CD25+ T-cells and HbA1c percentage among patients group (p &lt; 0.05).Also a significant difference in the percentage of CD4+ CD25+ T-cells was found when patients with HbA1c8% (the latter group had significantly lower percentage of CD4+ CD8+ T-cells). Conclusion: Type 1diabetes is characterised at its onset by a lowered percentage of CD8+ and CD8+ CD25+ T-cells in peripheral blood, a normal percentage of CD4+ and CD4+ CD25+ T-cells. There may be an inverse correlation between percentage of CD4+ CD25+ T-cells at disease onset and HbA1c level after three months. These data support the hypothesis that a defect in function or deficiency in number of T- regulatory cells may affect the pathogenesis of type 1 diabetes.Keywords: Type 1 diabetes, cell-mediated immunity, childrenEgypt J Pediatr Allergy Immunol 2008; 6(2): 69-7

    Sorption Effectiveness of Nannochloropsis salina Towards Mn2+ Ion in Different Salinity Waters

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    Research on sorption effectiveness of Nannochloropsis salina towards Mn2+ ion in different salinity waters has been carried out. This research was conducted to observe the effectiveness of N. salina as biosorbent for Mn2+pollutants in waters. Addition of Mn2+ ion with concentrations of 2, 4, and 8 ppm respectively, was conducted at the beginning of the  N. salina growth in Conwy Medium. Those variations were conducted at salinity of 5‰ and 30‰, aeration, continuous illumination, and also at temperature of 20 oC. The N. salina growth after addition of metal ion was observed every day using haemocytometer and the concentration of metal ion after adsorption was determined by atomic absorption spectrophotometer. Results showed that the optimum time for growth of N. salina as a control was obtained on day 8th at 30‰  salinity while at 5‰  salinity was obtained on day 15th except for 8 ppm Mn2+ was obtained on day 19th. The maximum  removal efficiency of Mn2+ with the concentrations of 2; 4; and 8 ppm at 30‰  salinity medium was 52.50; 59.25 and 55.38% respectively and for 5‰  salinity, the maximum removal efficiency of Mn2+ concentrations of  2, 4 and 8 ppm were 65.50; 64.66 and 67.20% respectively. The optimum time for growth of N. salina at 5‰ salinity medium is higher than at 30‰ salinity but the removal efficiency is conversely associated

    Rapid turnover of T cells in acute infectious mononucleosis.

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    During acute infectious mononucleosis (AIM), large clones of Epstein-Barr virus-specific T lymphocytes are produced. To investigate the dynamics of clonal expansion, we measured cell proliferation during AIM using deuterated glucose to label DNA of dividing cells in vivo, analyzing cells according to CD4, CD8 and CD45 phenotype. The proportion of labeled CD8(+)CD45R0(+) T lymphocytes was dramatically increased in AIM subjects compared to controls (mean 17.5 versus 2.8%/day; p<0.005), indicating very rapid proliferation. Labeling was also increased in CD4(+)CD45R0(+) cells (7.1 versus 2.1%/day; p<0.01), but less so in CD45RA(+) cells. Mathematical modeling, accounting for death of labeled cells and changing pool sizes, gave estimated proliferation rates in CD8(+)CD45R0(+) cells of 11-130% of cells proliferating per day (mean 47%/day), equivalent to a doubling time of 1.5 days and an appearance rate in blood of about 5 x 10(9) cells/day (versus 7 x 10(7) cells/day in controls). Very rapid death rates were also observed amongst labeled cells (range 28-124, mean 57%/day),indicating very short survival times in the circulation. Thus, we have shown direct evidence for massive proliferation of CD8(+)CD45R0(+) T lymphocytes in AIM and demonstrated that rapid cell division continues concurrently with greatly accelerated rates of cell disappearance
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