262 research outputs found

    Prediction of Modulus of Rupture from Modulus of Elasticity for Some Egyptian Hardwoods

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    The MOE and MOR of 112 air-dry small, clear specimens (2 x 2 x 30 cm) of six species of hardwoods grown in Egypt were determined. Simple linear regression analysis revealed that MOR is highly correlated with MOE of Eucalyptus camaldulensis, Khaya senegalensis, Tamarix articulata and Casuarina spp. However, the "r" values for Jacaranda ovalifolia and Melia azedarach were not significant. In addition, covariance analysis showed that the six regressions equations have different slopes and Y-intercepts and therefore cannot be grouped. The only grouping was that between the regression lines of the first three species mentiones above.Introducing specific gravity in the regression equation did not result in improving the correlation coefficients, except in the case of Casuarina spp. Using specific gravity alone for predicting the MOR was found to be unreliable due to the relatively low "r" values obtained for the species except in the case of Casuarina spp

    Pulpal blood flow changes and pain scores related to using superelastic 0.018-inch nickel titanium as the first orthodontic alignment archwire: A prospective clinical trial

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    Background: Optimal orthodontic force results in maximum rate of tooth movement without tissue damage. Even though starting orthodontic treatment with a thicker archwire may shorten treatment duration, the evidence on the effect of using 0.018-inch NiTi as the first alignment archwire on pulpal blood flow (PBF) status is still scarce. Objectives: to record PBF changes and pain scores associated with using 0.018-inch NiTi as the first alignment archwire during fixed orthodontic treatment. Methodology: Patients were selected from subjects attending postgraduate orthodontic teaching clinics at Jordan University of Science and Technology. In total, forty healthy patients who exhibited mild lower arch crowding were included. A split-mouth trial design was used. Each patient received two archwire sizes at one time joined in the midline by crimpable hook and applied in the lower arch. Patients were assigned into one of two groups based on archwire sizes used. Group 1: 0.014-inch and 0.018-inch NiTi (Six males, 14 females aged 19.4±1.33 years) and Group 2: 0.016-inch and 0.018-inch NiTi (Seven males, 13 females aged 19.6±1.45 years). The archwire size group was randomly allocated with a 1:1 allocation ratio. A Laser Doppler Flowmeter was used to measure PBF at different time intervals (T0-T5). Pain scores were recorded using a visual analogue scale (VAS). A repeated measures ANOVA and a post-hoc Bonferroni comparison tests were conducted to examine differences at the different time points before and during orthodontic alignment. Results: For all studied archwire sizes, PBF decreased 20 minutes after their placement. Most PBF changes occurred within 24hours and continued to decrease until 72 hours after archwire placement where the maximum reduction was reached. Eventually, normal values were reverted within 1 month. PBF changes were similar between all alignment – groups. Conclusions: Initial orthodontic alignment with 0.018-inch NiTi does not cause irreversible changes to pulpal vasculature or produces higher pain scores.The study was supported by the deanship of research at Jordan University of Science and Technology, research grant number (39/2018)

    Multiwavelength Observations of 1ES 1959+650, One Year After the Strong Outburst of 2002

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    In April-May 2003, the blazar 1ES 1959+650 showed an increased level of X-ray activity. This prompted a multiwavelength observation campaign with the Whipple 10 m gamma-ray telescope, the Rossi X-ray Timing Explorer, the Bordeaux Optical Observatory, and the University of Michigan Radio Astrophysical Observatory. We present the multiwavelength data taken from May 2, 2003 to June 7, 2003 and compare the source characteristics with those measured during observations taken during the years 2000 and 2002. The X-ray observations gave a data set with high signal-to-noise light curves and energy spectra; however, the gamma-ray observations did not reveal a major TeV gamma-ray flare. Furthermore, we find that the radio and optical fluxes do not show statistically significant deviations from those measured during the 2002 flaring periods. While the X-ray flux and X-ray photon index appear correlated during subsequent observations, the apparent correlation evolved significantly between the years 2000, 2002, and 2003. We discuss the implications of this finding for the mechanism that causes the flaring activity.Comment: 17 pages, 6 figures, 2 table

    Multiwavelength Observations of the Blazar Mrk 421 in December 2002 and January 2003

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    We report on a multiwavelength campaign on the TeV gamma-ray blazar Markarian (Mrk) 421 performed during December 2002 and January 2003. These target of opportunity observations were initiated by the detection of X-ray and TeV gamma-ray flares with the All Sky Monitor (ASM) on board the Rossi X-ray Timing Explorer (RXTE) and the 10 m Whipple gamma-ray telescope.The campaign included observational coverage in the radio (University of Michigan Radio Astronomy Observatory), optical (Boltwood, La Palma KVA 0.6m, WIYN 0.9m), X-ray (RXTE pointed telescopes), and TeV gamma-ray (Whipple and HEGRA) bands. At TeV energies, the observations revealed several flares at intermediate flux levels, peaking between 1 and 1.5 times the flux from the Crab Nebula. While the time averaged spectrum can be fitted with a single power law of photon index Gamma =2.8, we find some evidence for spectral variability. Confirming earlier results, the campaign reveals a rather loose correlation between the X-ray and TeV gamma-ray fluxes. In one case, a very strong X-ray flare is not accompanied by a comparable TeV gamma-ray flare. Although the source flux was variable in the optical and radio bands, the sparse sampling of the optical and radio light curves does not allow us to study the correlation properties in detail. We present a simple analysis of the data with a synchrotron-self Compton model, emphasizing that models with very high Doppler factors and low magnetic fields can describe the data.Comment: Accepted for publication in the Astrophysical Journa

    The First VERITAS Telescope

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    The first atmospheric Cherenkov telescope of VERITAS (the Very Energetic Radiation Imaging Telescope Array System) has been in operation since February 2005. We present here a technical description of the instrument and a summary of its performance. The calibration methods are described, along with the results of Monte Carlo simulations of the telescope and comparisons between real and simulated data. The analysis of TeV γ\gamma-ray observations of the Crab Nebula, including the reconstructed energy spectrum, is shown to give results consistent with earlier measurements. The telescope is operating as expected and has met or exceeded all design specifications.Comment: Accepted by Astroparticle Physic

    A data-driven synthesis of research evidence for domains of hearing loss, as reported by adults with hearing loss and their communication partners

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    A number of assessment tools exist to evaluate the impact of hearing loss, with little consensus among researchers as to either preference or psychometric adequacy. The item content of hearing loss assessment tools should seek to capture the impact of hearing loss on everyday life, but to date no one has synthesized the range of hearing loss complaints from the perspectives of the person with hearing loss and their communication partner. The current review aims to synthesize the evidence on person with hearing loss- and communication partner-reported complaints of hearing loss. Searches were conducted in Cos Conference Papers Index, the Cumulative Index to Nursing and Allied Health Literature, Excerpta Medica Database, PubMed, Web of Science, and Google Scholar to identify publications from May 1982 to August 2015. A manual search of four relevant journals updated the search to May 2017. Of the 9,516 titles identified, 78 records (comprising 20,306 participants) met inclusion criteria and were taken through to data collection. Data were analyzed using meta-ethnography to form domains representing the person with hearing loss- and communication partner-reported complaints of hearing loss as reported in research. Domains and subdomains mutual to both perspectives are related to ‘‘Auditory’’ (listening, communicating, and speaking), ‘‘Social’’ (relationships, isolation, social life, occupational, and interventions), and ‘‘Self’’ (effort and fatigue, emotions, identity, and stigma). Our framework contributes fundamental new knowledge and a unique resource that enables researchers and clinicians to consider the broader impacts of hearing loss. Our findings can also be used to guide questions during diagnostic assessment and to evaluate existing measures of hearing loss

    Lifetime measurements of lowest states in the πg<sub>7/2</sub>⊗νh<sub>11/2</sub> rotational band in <sup>112</sup>I

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    A differential-plunger device was used to measure the lifetimes of the lowest states in the πg7/2 ⊗ νh11/2 rotational band in doubly odd 112I with the 58Ni(58Ni, 3pn) reaction. A differential decay curve method was performed using the fully shifted and degraded γ -ray intensity measurements as a function of target-to-degrader distance. The lifetimes of the lowest three states in the πg7/2 ⊗ νh11/2 band in 112I were measured to be 124(30), 130(25), and 6.5(5) ps, respectively. As the lifetimes of successive excited states in a rotational band are expected to decrease with increasing excitation energy, these measurements suggest that the order of the transitions in the established band in 112I may need revising and that the state tentatively assigned to be (7−) may not belong to the rotational band.peerReviewe

    Shape coexistence in Hg-178

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    Lifetime measurements of excited states in Hg-178 have been performed using the Rh-103(Kr-78, p2n) reaction at a beam energy of 354 MeV. The recoil-decay tagging (RDT) technique was applied to select the Hg-178 nuclei and associate the prompt gamma rays with the correlated characteristic ground-state alpha decay. Lifetimes of the four lowest yrast states of Hg-178 have been determined using the recoil distance Doppler-shift (RDDS) method. The experimental data are compared to theoretical predictions with focus on shape coexistence. The results confirm the shift of the deformed prolate structures to higher lying states but also indicate their increasing deformation with decreasing neutron number.Peer reviewe

    Influence of sense of coherence on adolescents' self-perceived dental aesthetics:a cross-sectional study

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    Background Sense of coherence (SOC) is a psychosocial factor capable of influencing perception of health, improving one’s ability to manage life. It is the central construct of salutogenesis. SOC allows for identification and mobilization of resources to effectively manage or solve problems, promoting health and quality of life. Using Wilson-Cleary’s conceptual model we hypothesized that SOC might contribute to self-perception of dental aesthetics. The aim of this study was to investigate whether SOC levels were related to self-perception of dental aesthetics against assessed normative orthodontic treatment need among adolescents. Methods A cross-sectional study was conducted with 615 male and female adolescents aged 12 to 15 years. Data collection comprised socio-demographic and socio-economic characteristics, SOC (SOC 13), self-perceived dental aesthetics (Oral Aesthetic Subjective Impact Scale), and assessment of orthodontic treatment need (Dental Aesthetic Index). Statistical analysis involved Pearson’s chi-square test, Kruskal-Wallis test, Mann-Whitney test and multiple linear regression. Spearman’s correlation coefficient was calculated for the determination of the strength of correlations among the numerical variables. The level of significance was set at 5% (p < 0.05). Results 50.1% of the participants were classified as having a high SOC (≥ median). Overall, SOC was associated with self-perceived dental aesthetics (p = 0.048). In the adolescents with no orthodontic treatment need, those with a low SOC perceived their dental aesthetics more negatively than those with high levels of SOC. The multiple regression analysis demonstrated an inverse relationship between SOC and: 1) age (p = 0.007), SOC being higher in the younger age group; 2) self-perceived dental aesthetics (p = 0.001), a higher SOC being associated with those who had a positive dental self-perception. Conclusions SOC was associated with self-perceived dental aesthetics and adolescents with a high SOC were more likely to perceive their dental aesthetics more positively. SOC did not seem to influence self-perception of dental aesthetics in adolescents who were clinically assessed as having an orthodontic treatment need, however, in those where there was no orthodontic treatment need, a low SOC was associated with a negative self-perception of dental appearance

    Evidence for octupole collectivity in Pt-172

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    Excited states in the extremely neutron-deficient nucleus Pt-172 were populated via Ru-96(Kr-78, 2p) and Mo-92(Kr-83, 3n) reactions. The level scheme has been extended up to an excitation energy of approximate to 5MeV and tentative spin-parity assignments up to I-pi = 18(+). Linear polarization and angular distribution measurements were used to determine the electromagnetic E1 character of the dipole transitions connecting the positive-parity ground-state band with an excited side-band, firmly establishing it as a negativeparity band. The lowestmember of this negative-parity structure was firmly assigned spin-parity 3(-). In addition, we observed an E3 transition from this 3(-) state to the ground state, providing direct evidence for octupole collectivity in Pt-172. Large-scale shell model (LSSM) and total Routhian surface (TRS) calculations have been performed, supporting the interpretation of the 3(-) state as a collective octupole-vibrational state.Peer reviewe
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