6,072 research outputs found

    CanalPro EAL Accuracy compared to the Root ZX EAL

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    CanalPro Electronic Apex Locator Accuracy Compared to the Root ZX Electronic Apex locator Benjamin Brown, Garry Myers, Caroline Carrico, Duane Schaefer Department of Endodontics, Virginia Commonwealth University Objectives: Electronic apex locators (EAL) are an effective instrument in measuring the working length of a canal. The Root ZX is considered the gold standard by many. The aim of this research is to compare the accuracy of the CanalPro EAL to the Root ZX. Methods: The actual length of 43 single rooted extracted teeth were measured with a #10 hand file when the tip was visualized at the foramen under a microscope. The EAL was then hooked up to a jig, with the tooth in saline, and a #10 hand file was placed in the canal. The working length was determined by using the 0.5 mm mark on both the CanalPro and Root ZX EAL. Results: With the Root ZX, 74% of the teeth were within 0.5mm of the actual length (32/43). For the CanalPro, 65% were within 0.5mm (28/43). Neither the CanalPro nor the RootZX were deemed equivalent based on the preset equivalence bounds of +/- 0.5mm. Conclusions: According to this study, both the Root ZX and the CanalPro are clinically acceptable for determining the apical limit for root canal therapy when using the ‘0.5’ mark, however it is advised that a MAF or MAC radiograph to confirm that instrumentation and obturation are within the confines of the canal. If using the ‘Apex’ mark on the EAL, then 1 mm should be subtracted from this length to ensure the limit of cleaning, shaping, and obturation are within the confines of the AC

    The biopsychosocial model and hypothyroidism

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    This paper comments on the role and emergence of the biopsychosocial model in modern medical literature and health care settings. The evolution of the biopsychosocial model and its close association with modern pain theory is also examined. This paper seeks to discuss the place of this model with respect to the management of hypothyroidism. This discussion represents a forerunner to a randomised control trial that will seek to investigate the effect of a biopsychosocial-based treatment regime on hypothyroidism

    Modeling impact of intertidal foreshore evolution on gravel barrier erosion and wave runup with XBeach-X

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    This paper provides a sensitivity analysis around how characterizing sandy, intertidal foreshore evolution in XBeach-X impacts on wave runup and morphological change of a vulnerable, composite gravel beach. The study is motivated by a need for confidence in storm-impact modeling outputs to inform coastal management policy for composite beaches worldwide. First, the model is run with the sandy settings applied to capture changes in the intertidal foreshore, with the gravel barrier assigned as a non-erodible surface. Model runs were then repeated with the gravel settings applied to obtain wave runup and erosion of the barrier crest, updating the intertidal foreshore from the previous model outputs every 5, 10 and 15 min, and comparing this with a temporally static foreshore. Results show that the scenario with no foreshore evolution led to the highest wave runup and barrier erosion. The applied foreshore evolution setting update is shown to be a large control on the distribution of freeboard values indicative of overwash hazard and barrier erosion by causing an increase (with 5 min foreshore updates applied) or a decrease (with no applied foreshore updating) in the Iribarren number. Therefore, the sandy, intertidal component should not be neglected in gravel barrier modeling applications given the risk of over- or under-predicting the wave runup and barrier erosion

    Internally heated and fully compressible convection: flow morphology and scaling laws

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    In stars and planets natural processes heat convective flows in the bulk of a convective region rather than at hard boundaries. By characterizing how convective dynamics are determined by the strength of an internal heating source we can gain insight into the processes driving astrophysical convection. Internally heated convection has been studied extensively in incompressible fluids, but the effects of stratification and compressibility have not been examined in detail. In this work, we study fully compressible convection driven by a spatially uniform heating source in 2D and 3D Cartesian, hydrodynamic simulations. We use a fixed temperature upper boundary condition which results in a system that is internally heated in the bulk and cooled at the top. We find that the flow speed, as measured by the Mach number, and turbulence, as measured by the Reynolds number, can be independently controlled by separately varying the characteristic temperature gradient from internal heating and the diffusivities. 2D simulations at a fixed Mach number (flow speed) demonstrate consistent power at low wavenumber as diffusivities are decreased. We observe convection where the velocity distribution is skewed towards cold, fast downflows, and that the flow speed is related to the length scale and entropy gradient of the upper boundary where the downflows are driven. We additionally find a heat transport scaling law which is consistent with prior incompressible work.Comment: 22 pages, 12 figures, submitted to Phys. Rev. Fluid

    Weak Boson Production Amplitude Zeros; Equalities of the Helicity Amplitudes

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    We investigate the radiation amplitude zeros exhibited by many Standard Model amplitudes for triple weak gauge boson production processes. We show that WZγWZ\gamma production amplitudes have especially rich structure in terms of zeros, these amplitudes have zeros originating from several different sources. It is also shown that TYPE I current null zone is the special case of the equality of the specific helicity amplitudes.Comment: 27 pages, 12 figures, 2 table

    The Clustering of Extremely Red Objects

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    We measure the clustering of Extremely Red Objects (EROs) in ~8 deg^2 of the NOAO Deep Wide Field Survey Bo\"otes field in order to establish robust links between ERO z~1.2 and local galaxy z<0.1 populations. Three different color selection criteria from the literature are analyzed to assess the consequences of using different criteria for selecting EROs. Specifically, our samples are (R-K_s)>5.0 (28,724 galaxies), (I-K_s)>4.0 (22,451 galaxies) and (I-[3.6])>5.0 (64,370 galaxies). Magnitude-limited samples show the correlation length (r_0) to increase for more luminous EROs, implying a correlation with stellar mass. We can separate star-forming and passive ERO populations using the (K_s-[24]) and ([3.6]-[24]) colors to K_s=18.4 and [3.6]=17.5, respectively. Star-forming and passive EROs in magnitude limited samples have different clustering properties and host dark halo masses, and cannot be simply understood as a single population. Based on the clustering, we find that bright passive EROs are the likely progenitors of >4L^* elliptical galaxies. Bright EROs with ongoing star formation were found to occupy denser environments than star-forming galaxies in the local Universe, making these the likely progenitors of >L^* local ellipticals. This suggests that the progenitors of massive >4L^* local ellipticals had stopped forming stars by z>1.2, but that the progenitors of less massive ellipticals (down to L^*) can still show significant star formation at this epoch.Comment: 19 pages, 16 figures, 4 tables, Accepted to ApJ 27th November 201
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