271 research outputs found

    Comparison between OQPSK and DPSK bidirectional radio over fiber transmission systems

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    Radio over fiber is becoming an increasingly important technology for the wireless market since it introduces a higher data transmission rate and large bandwidth. In this paper, we have compared OQPSK and DPSK bidirectional radio over fiber ROF systems, where an offset quadrature phase shift keying (OQPSK) or differential phase shift keying (DPSK) signals are used for down-link and an on-off keying (OOK) signal re-modulated for up-link. Several measurements were performed including Bit Error Rate (BER) curves for uplink and downlink, RSOA gain curve and noise figure with the variation of input power and temperature for each system

    Penta-Band Dielectric Loaded Folded Loop Antenna for Mobile Handset

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    A compact internal penta-band folded loop antenna for LTE1600/2600/WIMAX3. 5/WLAN2. 4/5.2 multiple mobile operations is proposed and investigated. The whole antenna structure is formed of a single folded meander loop pattern mount on the surfaces of a dielectric carrier with L-shape have a volume of 20 mm× 17mm× 5 mm, and ground plane of length 110mm is used. The size of the total structure is 110× 50× 5mm3. The compact structure makes it very suitable for today’s mobile phones applications. With 6 dB return loss, five operating frequency bands covering LTE/WLAN/WiMAX MHz can be achieved with our design. Also, the resonant characteristics of the antenna can be tuned by using various strip dimensions and also the dielectric material of the carrier. Moreover, simulated results exhibit that the proposed folded loop antenna features nearly good omnidirectional radiation patterns with proper gain. The design and optimizing of the performance of the proposed antenna are performed by using a high frequency structure simulator HFSS. Details of the various antenna parameters are presented and discussed in this paper

    Relationship of self-rated health with fatal and non-fatal outcomes in cardiovascular disease: a systematic review and meta-analysis.

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    BACKGROUND: People who rate their health as poor experience higher all-cause mortality. Study of disease-specific association with self-rated health might increase understanding of why this association exists. OBJECTIVES: To estimate the strength of association between self-rated health and fatal and non-fatal cardiovascular disease. METHODS: A comprehensive search of PubMed MEDLINE, EMBASE, CINAHL, BIOSIS, PsycINFO, DARE, Cochrane Library, and Web of Science was undertaken during June 2013. Two reviewers independently searched databases and selected studies. Inclusion criteria were prospective cohort studies or cohort analyses of randomised trials with baseline measurement of self-rated health with fatal or non-fatal cardiovascular outcomes. 20 studies were pooled quantitatively in different meta-analyses. Study quality was assessed using Newcastle-Ottawa scales. RESULTS: 'Poor' relative to 'excellent' self-rated health (defined by most extreme categories in each study, most often' poor' or 'very poor' and 'excellent' or 'good') was associated over a follow-up of 2.3-23 years with cardiovascular mortality in studies: where varying degrees of adjustments had been made for cardiovascular disease risk (HR 1.79 (95% CI 1.50 to 2.14); 15 studies, I2 = 71.24%), and in studies reporting outcomes in people with pre-existing cardiovascular disease or ischaemic heart disease symptoms (HR 2.42 (95% CI 1.32 to 4.44); 3 studies; I2 = 71.83%). 'Poor' relative to 'excellent' self rated health was also associated with the combined outcome of fatal and non-fatal cardiovascular events (HR 1.90 (95% CI 1.26 to 2.87); 5 studies; I2 = 68.61%), Self-rated health was not significantly associated with non-fatal cardiovascular disease outcomes (HR 1.66 (95% CI 0.96 to 2.87); 5 studies; I2 = 83.60%). CONCLUSIONS: Poor self rated health is associated with cardiovascular mortality in populations with and without prior cardiovascular disease. Those with current poor self-rated health may warrant additional input from health services to identify and address reasons for their low subjective health.This is the final published version. It is accessible from the PLOS One website at: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0103509

    Symmetric 80 Gbps Next Generation Passive Optical Network Stage Two NG-PON2

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    In this research, a design of a symmetric 80 Gbps Passive Optical Network that meets the requirements of Next Generation Passive Optical Network Stage Two (NG-PON2) is proposed. According to The Full-Service Access Network (FSAN), The Time and Wave Length Division Multiplexing (TWDM) is chosen as the best solution to implement NG-PON2. TWDM network of NG-PON2 can be implemented in many wavelength plans to replace or co-exist with previous PON technologies. The proposed design was simulated taking into consideration the practical parameters of existing systems, the results shows that the system is reliable for implementation for 80 Gbps bitrate utilizing 8 pairs of wavelengths transmitted over 40 Km and distributed and received by 128 users with acceptable data rate

    Prediction of 3-dimensional coverage surface area of the femoral head in hip dysplasia through conventional computed tomography

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    BACKGROUND: Assessment of 3-dimensional (3D) femoral head coverage is critical in evaluating, preoperative planning, and treating hip dysplasia. PURPOSE: To (1) propose a mathematical model to establish 3D femoral head coverage using conventional computed tomography (CT), (2) determine the correlation of 2D parameters with 3D coverage, and (3) characterize the patterns of dysplasia based on 3D morphology. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: We identified 30 patients (n = hips) with symptomatic dysplasia and 30 patients (n = hips) without dysplasia. Patients with dysplastic hips were matched with regard to sex, age, and body mass index to those with nondysplastic hips. Preoperative CTs were analyzed using 3D software, and 3D femoral head surface area coverage (FHSAC; in %) was assessed in 4 quadrant zones: anteromedial, anterolateral, posteromedial, and posterolateral. To assess lateral coverage of the femoral head, we introduced the anterolateral femoral head coverage angle (ALFC) and the posterolateral femoral head coverage angle (PLFC). RESULTS: Reduced femoral head coverage was more pronounced in dysplastic versus nondysplastic hips in the anterolateral quadrant (18% vs 40.7%, respectively) and posterolateral quadrant (35.8% vs 56.9%, respectively) ( CONCLUSION: The ALFC and The PLFC were strongly correlated with 3D lateral FHSAC and were able to predict 3D coverage accurately

    Follicle-Stimulating Hormone Receptor Polymorphism in Infertile Palestinian Men

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    Follicle stimulating hormone (FSH) is necessary for normal reproduction. Follicle stimulating hormone receptor (FSHR) signaling stimulates proliferation of Sertoli cells and maintains spermatogenesis. This work aimed toinvestigate FSHR polymorphism in infertile Palestinian men. 56 males grouped into 24 normozoospermic controls, and 32 infertile males. Infertile males were grouped into 11 azoospermic males, and 21 oligozoospermic males. Semen analysis, FSH, Luteinizing hormone (LH) and Total testosterone were determined. Allelic variant of FSHR gene was determined by PCR-RFLP. Sperm count was significantly decreased in oligospermia and azoospermia compared to control. Sperm motility showed significant differences between the different groups of men.LH and FSH were significantly increased in azoospermia compared to controls and compared to oligospermia. The T testosterone was significantly decreased in oligospermia and azoospermia compared to controls. The SNPs of FSHR allele showed no significant difference in the prevalence of FSHR among the three groups. Sperm count was significantly decreased in mutant (Ser/Ser) FSHR allele compared to wild (Asn/Asn) FSHR allele. On the other hand, sperm motility showed no significant differences among various groups. LH was significantly increased in mutant FSHR allele compared to wildFSHR allele, whereas the T testosterone was significantly decreased in mutant FSHR allele compared to wildFSHR allele. However, there was no significant difference in FSH among various groups. It is conclude that the presence of mutant (Ser/Ser) FSHR allele is observed to be a cause for a decreased in a sperm count and T testosterone and increased of LH level

    Systematic Surface Phase Transition of Ag Thin Films by Iodine Functionalization at Room Temperature Evolution of Optoelectronic and Texture Properties

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    We show a simple room temperature surface functionalization approach using iodine vapour to control a surface phase transition from cubic silver (Ag) of thin films into wurtzite silver-iodid (beta-AgI) films. A combination of surface characterization techniques (optical, electronical and structural characterization) reveal distinct physical properties of the new surface phase. We discuss the AgI thin film formation dynamics and related transformation of physical properties by determining the work-function, dielectric constant and pyroelectric behavior together with morphological and structural thin film properties such as layer thickness, grain structure and texture formation. Notable results are: (i) a remarkable increase of the work-function (by 0.9 eV) of the Ag thin layer after short a iodine exposure time (<= 60 s), with simultaneous increase of the thin film transparency (by two orders of magnitude), (ii) pinning of the Fermi level at the valance band maximum upon iodine functionalization, (iii) 84% of all crystallites grain were aligned as a result of the evolution of an internal electric field. Realizing a nanoscale layer stack composed of a dielectric AgI layer on top of a metallic thin Ag layer with such a simple method has some technological implications e.g. to realize optical elements such as planar optical waveguides

    Socio-Economic Factors Affecting the Income of Small-scale Agroforestry Farms in Hill Country Areas in Yemen: A comparison of OLS and WLS Determinants

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    Yemen is a less-developed country in the Arabian Peninsula, with only 3% arable land. An agroforestry land-use system has been practiced traditionally by small-scale farmers, but is associated with low productivity and income. A study has been undertaken to determine the socio-economic attributes of farmers that influence the financial performance of agroforestry and nonagroforestry farms in the Bura’a Mountain region. A survey was conducted of 150 farmers involved in both agroforestry and non-agroforestry. Both OLS and WLS regression were applied, and coefficients compared in terms of consistency and goodness of fit. Incomes of farmers were found to be influenced by education, area of land, livestock holding, family size, and whether coffee is grown, but not farmer’s age. The WLS method produced efficient and consistent results, whereas OLS regression was affected by the heteroscedasticity. The findings of the study indicate that the farmers of the study area are in need of financial and technical support from government to increase their income. Infrastructural development and public intervention in developing farmers’ technical know-how could enhance production and ensure the optimum use of land as well as soil and water conservation

    A genome phylogeny for mitochondria among alpha-proteobacteria and a predominantly eubacterial ancestry of yeast nuclear genes

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    Analyses of 55 individual and 31 concatenated protein data sets encoded in Reclinomonas americana and Marchantia polymorpha mitochondrial genomes revealed that current methods for constructing phylogenetic trees are insufficiently sensitive (or artifact-insensitive) to ascertain the sister of mitochondria among the current sample of eight alpha-proteobacterial genomes using mitochondrially-encoded proteins. However, Rhodospirillum rubrum came as close to mitochondria as any alpha-proteobacterium investigated. This prompted a search for methods to directly compare eukaryotic genomes to their prokaryotic counterparts to investigate the origin of the mitochondrion and its host from the standpoint of nuclear genes. We examined pairwise amino acid sequence identity in comparisons of 6,214 nuclear protein-coding genes from Saccharomyces cerevisiae to 177,117 proteins encoded in sequenced genomes from 45 eubacteria and 15 archaebacteria. The results reveal that approximately 75% of yeast genes having homologues among the present prokaryotic sample share greater amino acid sequence identity to eubacterial than to archaebacterial homologues. At high stringency comparisons, only the eubacterial component of the yeast genome is detectable. Our findings indicate that at the levels of overall amino acid sequence identity and gene content, yeast shares a sister-group relationship with eubacteria, not with archaebacteria, in contrast to the current phylogenetic paradigm based on ribosomal RNA. Among eubacteria and archaebacteria, proteobacterial and methanogen genomes, respectively, shared more similarity with the yeast genome than other prokaryotic genomes surveyed
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