103 research outputs found

    Comparison of the poleward transport of ozone in the Northern and Southern Hemispheres

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    Six and one-half years of ozone data and temperature data are used to extend Geller et al.'s (1988) study comparing the transport of ozone to high latitudes in the Northern and Southern Hemispheres. In this earlier study, it was pointed out that the poleward transport of ozone varies annually in the Northern Hemisphere but has a marked semiannual behavior in the Southern Hemisphere. This earlier study covered the period from December 1978 to November 1982. Two and one-half additional years have now been analyzed so that the analysis now extends to July 1986. With this extended data set, the maximum rate of increase in total ozone is seen to occur in January in the Northern Hemisphere for all of the years investigated. In the Southern Hemisphere, the maximum rate of increase is seen in September for almost all of the years with a secondary maximum in the rate of increase in total ozone often being seen during March-April period. The nature of the seasonal variation in total ozone is found to be much more variable in the Southern Hemisphere than in the Northern Hemisphere

    Residual circulations calculated from satellite data: Their relations to observed temperature and ozone distributions

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    Monthly mean residual circulations were calculated from eight years of satellite data. The diabatic circulation is usually found to give a good approximation to the residual circulation, but this is not always the case. In particular, an example is shown at 60 deg S and 30 mbar where the diabatic and residual circulations show very different annual variations. Correlations between the vertical component of the residual circulation and temperature and ozone were computed. The computations indicate that yearly variations of temperatures in the tropics are under radiative control, except during stratospheric warmings. Interannual variations in seasonal mean temperatures are shown to be under dynamical control everywhere. Correlations between seasonal means of the vertical component of the residual circulation and ozone mixing ratios are consistent with what would be expected from the ozone variations being due to differences in the ozone transport, although transport effects cannot easily be distinguished from photochemical effects above the altitude of the ozone mixing ratio peak. Finally, variations in total ozone are examined in comparison with residual circulation variations. A one to two month phase lag is seen in the annual variation in the total ozone at 60 deg N with respect to the maximum downward residual motions. This phase lag is greater at 60 deg N than at 60 deg S. There is evidence at 60 deg S of a greater downward trend in the mean zonal ozone maxima than there is in the minima. A decreasing trend in the maximum descending motion is seen to accompany the ozone trend at 60 deg S

    Designing Teacher Professional Development for Mathematics Teaching with Variation Theory

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    In this study, we aimed at demonstrating the power of Variation Theory in exploring the local situation of Indonesian teachers and Teacher Professional Development program. The projection of Variation theory regarding the enterprise of teaching results on the need of sensitivity of students and exemplary teaching strategy that differ with teachers teaching style. Besides, It requires more opportunities for teachers to understand the critical feature of object of learning. By sequence of activity that elaborating variation theory and regards the local situation might imply the improvement of students learning

    Management of mesh complications following surgery for stress urinary incontinence or pelvic organ prolapse: a systematic review

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    Background: Mesh surgery for stress urinary incontinence or pelvic organ prolapse can result in complications such as mesh exposure, mesh extrusion, voiding dysfunction, dyspareunia, and pain. There is limited knowledge or guidance on the effective management for mesh‐related complications. Objective: To determine the best management of mesh complications; a systematic review was conducted as part of the national clinical guideline ‘Urinary incontinence (update) and pelvic organ prolapse in women: management’. Search strategy: Search strategies were developed for each indication for referral. Selection criteria: Relevant interventions included complete or partial mesh removal, mesh division, and non‐surgical treatments such as vaginal estrogen. Data collection and analysis: Characteristics and outcome data were extracted, and as a result of the heterogeneous nature of the data a narrative synthesis was conducted. Main results: Twenty‐four studies were included; five provided comparative data and four studies stated the indication for referral. Reported outcomes (including pain, dyspareunia, satisfaction, quality of life, incontinence, mesh exposure, and recurrence) and the reported incidences of these varied widely. Conclusions: The current evidence base is limited in quantity and quality and does not permit firm recommendations to be made on the most effective management for mesh‐related complications. Robust data are needed so that mesh complications can be managed effectively in the future

    Interpretation of complex structure by 3-D seismic modeling

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    Behavior of thorium–uranium (IV) phosphate–diphosphate sintered samples during leaching tests. Part II. Saturation processes

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    Sintered pellets of thorium–uranium (IV) phosphate–diphosphate solid solutions (β-Th4−xUx(PO4)4P2O7, β-TUPD) were altered in several acidic media. All the results reported in the first part of this paper confirmed the good chemical durability of the samples. The evolution of the normalized weight loss showed that, in several media, thorium quickly precipitates in a neoformed phosphate-based phase while uranium (IV) is released in the leachate due to its oxidation into the uranyl form. The characterization of neoformed phases was carried out through several techniques involving grazing XRD, infrared and μ-Raman spectroscopies, EPMA, SEM and TEM. SEM micrographies showed that the dissolution mainly occurs at the grain boundaries, leading to the break away of the grains: only the first 15 μm are altered for 2 months in 10−1 M HNO3. From EPMA and BET measurements, neither the chemical composition nor the specific surface area are significantly modified. Near equilibrium, two neoformed phases were observed and identified by grazing XRD and/or μ-Raman spectroscopy at the surface of the leached pellets: one is found to be amorphous and progressively turns into the crystallized thorium phosphate–hydrogenphosphate hydrate (TPHPH). From the results obtained, a chemical scheme of the dissolution of β-TUPD sintered samples is proposed. The behavior of the actinides in the gelatinous phase appears mainly driven by their oxidation state: thorium remains in the tetrapositive state and is quickly and quantitatively precipitated while uranium (IV) is oxidized into uranyl then released in the leachate. The Th-precipitation as TPHPH first appears scattered then covers the entire surface of the pellet, inducing a delay of the actinides release in the leachate. Both phases act as protective layers and should induce the significant delay of the release of actinides (Th, U) to the biosphere
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