414 research outputs found

    Efficacy of a bioactive alloplast, in the treatment of human periodontal osseous defects-a clinical study

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    Presently, bone replacement grafts are one of the modalities of therapy for which there is histologic evidence of regeneration coronal to the base of the previous osseous defect. Bioactive glasses are used extensively in medicine and dentistry. This study evaluated the additional efficacy of a bioactive alloplast, PerioGlas, in comparison with open flap debridement only. 8 systemically healthy volunteers were chosen, each having 2 collateral sites with ?6 mm clinical probing depth and radiographic evidence of an intrabony defect. Randomly, one defect was treated with open flap debridement plus bioactive glass (test) and the other with open flap debridement alone (control). At baseline, 3, 6, 9 months measurements were recorded which included plaque index, gingival index, pocket probing depth, clinical attachment level, and increase in gingival recession. Standardized radiographs were used to measure defect fill and alveolar crest resorption. The data were subjected to statistical analysis. Both treatments showed no significant differences between the two groups at any point of time. However, radiographically, bioactive glass group showed significant improvement in bone fill over the sites treated with open flap debridement alone. The alloplastic bone graft material, PerioGlas, demonstrated clinical advantages beyond that achieved by debridement alone

    Metacognitive awareness- evaluation and implications in medical students

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    Background: Medical education is at cross roads today with a mismatch between students’ expectations of their performance and the reality. This led us to explore the reason for the academic decline. During our search, we found that metacognitive awareness plays a key role in moulding the learning skills of adult learners. Hence this study was conducted to evaluate the metacognitive awareness of medical students studying in the first year of MBBS.Methods: 100 first year medical students were included in the study and metacognitive awareness inventory questionnaire, a validated tool was administered to the students. This measures metacognitive knowledge and regulation. The results were obtained, tabulated and analysed.Results: Metacognitive awareness among medical students was average. Metacognitive knowledge was found to be significantly better than regulation. On comparing the genders, we note that females have better metacognitive regulation while males score higher in metacognitive knowledge which was statistically significant.Conclusions: The findings of the present study points towards the need of introduction of metacognitive strategies in the medical curriculum with more emphasis on problem based learning in order to make our learners become independent thinkers and efficient care givers.  

    A Physics-Based Parameterization of Air–Sea Momentum Flux at High Wind Speeds and Its Impact on Hurricane Intensity Predictions

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    A new bulk parameterization of the air–sea momentum flux at high wind speeds is proposed based on coupled wave–wind model simulations for 10 tropical cyclones that occurred in the Atlantic Ocean during 1998–2003. The new parameterization describes how the roughness length increases linearly with wind speed and the neutral drag coefficient tends to level off at high wind speeds. The proposed parameterization is then tested on real hurricanes using the operational Geophysical Fluid Dynamics Laboratory (GFDL) coupled hurricane–ocean prediction model. The impact of the new parameterization on the hurricane prediction is mainly found in increased maximum surface wind speeds, while it does not appreciably affect the hurricane central pressure prediction. This helps to improve the GFDL model–predicted wind–pressure relationship in strong hurricanes. Attempts are made to provide physical explanations as to why the reduced drag coefficient affects surface wind speeds but not the central pressure in hurricanes

    Coleus monostachyus (P. Beauv.) A. J. Paton (Lamiaceae): A new addition to the flora of India

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    Coleus monostachyus (P. Beauv.) A. J. Paton is reported here as a new addition to the flora of India. It seems the seeds of this plant might have come along with the timbers imported from the SE Asian countries. A detailed morphological description based on the Indian plants and photographs are provided to facilitate easy and correct identification

    The Operational GFDL Coupled Hurricane–Ocean Prediction System and a Summary of Its Performance

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    The past decade has been marked by significant advancements in numerical weather prediction of hurricanes, which have greatly contributed to the steady decline in forecast track error. Since its operational implementation by the U.S. National Weather Service (NWS) in 1995, the best-track model performer has been NOAA’s regional hurricane model developed at the Geophysical Fluid Dynamics Laboratory (GFDL). The purpose of this paper is to summarize the major upgrades to the GFDL hurricane forecast system since 1998. These include coupling the atmospheric component with the Princeton Ocean Model, which became operational in 2001, major physics upgrades implemented in 2003 and 2006, and increases in both the vertical resolution in 2003 and the horizontal resolution in 2002 and 2005. The paper will also report on the GFDL model performance for both track and intensity, focusing particularly on the 2003 through 2006 hurricane seasons. During this period, the GFDL track errors were the lowest of all the dynamical model guidance available to the NWS Tropical Prediction Center in both the Atlantic and eastern Pacific basins. It will also be shown that the GFDL model has exhibited a steady reduction in its intensity errors during the past 5 yr, and can now provide skillful intensity forecasts. Tests of 153 forecasts from the 2004 and 2005 Atlantic hurricane seasons and 75 forecasts from the 2005 eastern Pacific season have demonstrated a positive impact on both track and intensity prediction in the 2006 GFDL model upgrade, through introduction of a cloud microphysics package and an improved air–sea momentum flux parameterization. In addition, the large positive intensity bias in sheared environments observed in previous versions of the model is significantly reduced. This led to the significant improvement in the model’s reliability and skill for forecasting intensity that occurred in 2006

    Impact of Upper-Tropospheric Temperature Anomalies and Vertical Wind Shear on Tropical Cyclone Evolution Using an Idealized Version of the Operational GFDL Hurricane Model

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    The GFDL hurricane modeling system, initiated in the 1970s, has progressed from a research tool to an operational system over four decades. This system is still in use today in research and operations, and its evolution will be briefly described. This study used an idealized version of the 2014 GFDL model to test its sensitivity across a wide range of three environmental factors that are often identified as key factors in tropical cyclone (TC) evolution: SST, atmospheric stability (upper-air thermal anomalies), and vertical wind shear (westerly through easterly). A wide range of minimum central pressure intensities resulted (905–980 hPa). The results confirm that a scenario (e.g., global warming) in which the upper troposphere warms relative to the surface will have less TC intensification than one with a uniform warming with height. The TC rainfall is also investigated for the SST–stability parameter space. Rainfall increases for combinations of SST increase and increasing stability similar to global warming scenarios, consistent with climate change TC downscaling studies with the GFDL model. The forecast system’s sensitivity to vertical shear was also investigated. The idealized model simulations showed weak disturbances dissipating under strong easterly and westerly shear of 10 m s−1. A small bias for greater intensity under easterly sheared versus westerly sheared environments was found at lower values of SST. The impact of vertical shear on intensity was different when a strong vortex was used in the simulations. In this case, none of the initial disturbances weakened, and most intensified to some extent

    Description and Analysis of the Ocean Component of NOAA’s Operational Hurricane Weather Research and Forecasting (HWRF) Model

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    The Princeton Ocean Model for Tropical Cyclones (POM-TC), a version of the three-dimensional primitive equation numerical ocean model known as the Princeton Ocean Model, was the ocean component of NOAA’s operational Hurricane Weather Research and Forecast Model (HWRF) from 2007 to 2013. The coupled HWRF–POM-TC system facilitates accurate tropical cyclone intensity forecasts through proper simulation of the evolving SST field under simulated tropical cyclones. In this study, the 2013 operational version of HWRF is used to analyze the POM-TC ocean temperature response in retrospective HWRF–POM-TC forecasts of Atlantic Hurricanes Earl (2010), Igor (2010), Irene (2011), Isaac (2012), and Leslie (2012) against remotely sensed and in situ SST and subsurface ocean temperature observations. The model generally underestimates the hurricane-induced upper-ocean cooling, particularly far from the storm track, as well as the upwelling and downwelling oscillation in the cold wake, compared with observations. Nonetheless, the timing of the model SST cooling is generally accurate (after accounting for along-track timing errors), and the ocean model’s vertical temperature structure is generally in good agreement with observed temperature profiles from airborne expendable bathythermographs

    Impact of Sea-State-Dependent Langmuir Turbulence on the Ocean Response to a Tropical Cyclone

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    Tropical cyclones are fueled by the air–sea heat flux, which is reduced when the ocean surface cools due to mixed layer deepening and upwelling. Wave-driven Langmuir turbulence can significantly modify these processes. This study investigates the impact of sea-state-dependent Langmuir turbulence on the three-dimensional ocean response to a tropical cyclone in coupled wave–ocean simulations. The Stokes drift is computed from the simulated wave spectrum using the WAVEWATCH III wave model and passed to the three-dimensional Princeton Ocean Model. The Langmuir turbulence impact is included in the vertical mixing of the ocean model by adding the Stokes drift to the shear of the vertical mean current and by including Langmuir turbulence enhancements to the K-profile parameterization (KPP) scheme. Results are assessed by comparing simulations with explicit (sea-state dependent) and implicit (independent of sea state) Langmuir turbulence parameterizations, as well as with turbulence driven by shear alone. The results demonstrate that the sea-state-dependent Langmuir turbulence parameterization significantly modifies the three-dimensional ocean response to a tropical cyclone. This is due to the reduction of upwelling and horizontal advection where the near-surface currents are reduced by Langmuir turbulence. The implicit scheme not only misses the impact of sea-state dependence on the surface cooling, but it also misrepresents the impact of the Langmuir turbulence on the Eulerian advection. This suggests that explicitly resolving the sea-state-dependent Langmuir turbulence will lead to increased accuracy in predicting the ocean response in coupled tropical cyclone–ocean models
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