28 research outputs found

    The heliospheric modulation of 3-10 Mev electrons: modeling of changes in the solar wind speed in relation to perpendicular polar diffusion

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    Abstract The discrepancy between cosmic ray model predictions representing solar minimum conditions in the heliosphere and the 3-10 MeV post-1998 electrons observations by the Kiel Electron Telescope (KET) onboard Ulysses suggests the need for consistent changes in model parameters with increasing solar activity. In order to reduce this discrepancy, an effort is made to model the KET observations realistically during periods of increased solar activity by applying an advanced three-dimensional, steady-state electron modulation model based on ParkerÕs transport equation including the Jovian electron source. Some elements of the diffusion tensor which were not previously emphasized are revisited. A new relation is also established between the latitudinal dependence of the solar wind speed and the perpendicular polar diffusion. Based on this relation, a transition of an average solar wind speed from solar minimum to solar maximum conditions, as observed on board the Ulysses spacecraft, is modeled on the concept of the time-evolution of large polar coronal holes. These changes are correlated to different scenarios of the enhancement of perpendicular polar diffusion. Effects of these scenarios are illustrated, as a series of steady-state solutions, on the computed 7 MeV Jovian and galactic electrons in comparison with 3-10 MeV electrons observed from the period 1998 to the end of 2003. It is shown that this approach improves compatibility with the KET observations but it also points to the need for a time-dependent electron modulation model to fully describe modulation during moderate to extreme solar maximum conditions

    Language rights, intercultural communication and the law in South Africa

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    This article seeks to explore the present language scenario in courts of law. The article makes use of section 6 of the Constitution of the Republic of South Africa (1996), as a point of departure. At face value this section seems to entrench the language rights of individuals. This would mean that individuals could request trials to be held in their mother tongues, with fluent and competent speakers of that mother tongue sitting on the bench. However, this has not materialised. Contrary to popular opinion, the article argues that individual language rights are to some extent entrenched in the Constitution, but there are no mechanisms to secure such rights in the public domain. The article argues that it is often only language privileges that are preserved in institutions such as the justice system. Legally speaking, there is an obligation on the State to provide interpreters to facilitate access to all eleven official languages in courts of law. This in itself presents numerous challenges. The article argues further that the corollary to this is that there is very little space for intercultural communication in courts of law (as defined by Ting-Toomey, 1999, and Gibson, 2002). There has been little or no capacity building in this regard. It is English, to some extent Afrikaans, and the western cultural paradigm, which prevails. The result is further communication breakdown and language intolerance. In this article, the notion of language rights in courts of law is explored against the backdrop of existing theories of intercultural communication

    Percutaneous nephrolithotomy in patients with chronic kidney disease: efficacy and safety

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    Although the effects of percutaneous nephrolithotomy (PCNL) on patients with normal functioning kidneys have been widely studied, the outcomes of PCNL in populations with renal insufficiency remain underreported. We aimed to examine the literature and evaluate the efficacy and safety of PCNL in this non-indexed patient group. A systematic search was performed in accordance with Cochrane guidelines. This systematic search served to identify original studies investigating PCNL carried out in the adult population with chronic kidney disease published over the past 20 years (since 1997).</p

    Safety, feasibility, and efficacy of bilateral synchronous percutaneous nephrolithotomy for bilateral stone disease: Evidence from a systematic Review

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    INTRODUCTION: With the evolution of endourologic technology, bilateral synchronous percutaneous nephrolithotomy (BS-PCNL) has emerged as a potentially practical intervention for patients with bilateral lithiasis. Although tradition has favored a staged approach, an increasing number of original studies have reported their experiences with the synchronous approach.MATERIALS AND METHODS: A Cochrane style search was performed after development of a sensitive and predefined search strategy. Primary outcomes measured were initial and final stone-free rate (SFR), drop in hemoglobin, hospital stay, operative time, and complication rates. Additional information was collected on (but not limited to) baseline characteristics, stone complexity, number of tracts made, success rate, and transfusion rate.RESULTS: From a total 187 studies, 11 were identified (published between 1997 and 2015), and they were included in this review. In total, 594 patients with a mean age of 46 years and a male:female ratio of 3:1 underwent BS-PCNL procedures, the majority of which was under the prone position. In 87.1% (range: 71.4%-100%) of cases, the synchronous approach was performed as planned. Multiple access tracts were established in an average of 16.7% (4.1%-24%) renal units. Mean initial SFR and final SFR were 72.6% (49%-85%) and 92.4% (87%-96.9%), respectively, with a mean operative time of 171.1 minutes (range: 107.4-269 minutes). Mean hospital stay was 3.9 days (range: 1.25-15 days). Mean complication rate per study was 23.4% (range: 12.1%-54% per study). The majority were Clavien Grade 1 (60.9%), of which fever resolving spontaneously was the most common complication. No deaths were reported in any of the papers.CONCLUSION: BS-PCNL seems to be a good endourologic approach for patients with bilateral stone disease, which can render high SFRs and maintain a noninferior safety profile compared with the staged approach. This technique demands careful patient selection, counseling and should be preferably performed in endourology centers with large case volumes.</p
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