353 research outputs found

    Management of incomplete abortions at South African public hospitals

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    Objective. The objective of this report was to review and describe the management of incomplete abortion by public sector hospitals.Design. A descriptive study in which data were collected prospectively from routine hospital records on all women admitted with incomplete abortion to a stratified random sample of hospitals between 14 and 28 September 1994.Setting. Public sector hospitals in South Africa.Patients. Women with incomplete abortions.Main outcome measures. Length of hospital stay, details of medical management, details of surgical management, determinants of the above.Main results. Data were collected on 803 patients from the 56 participating hospitals. Of these, 767 (95.9%) were in hospital for 1 day or more, and 753 (95.3%) women underwent evacuation of the uterus. Sharp curettage wasthe method employed in 726 (96.9%) and general anaesthesia was used for 601 (88%) of the women requiring uterine evacuation. Antibiotics were prescribed for 396 (49.5%) and blood transfusions were administered to 125 (17%) women. Statistical analysis showed length of stay to be longer in small hospitals (under 500 beds) and when the medical condition was more severe. Antibiotic  usage and blood transfusion were more common with increasing severity and a low haemoglobin level on admission. However, some inappropriate management was identified with regard to both.Main conclusions. It is suggested that uncomplicated incomplete abortion can be more effectively and safely managed using the manual vacuum aspiration technique with sedation/analgesia as an outpatient procedure. Attention should be directed at the introduction of this management routine at all types of hospital and to the ensuring of appropriate management of women with complicated abortion

    An avalanche-photodiode-based photon-number-resolving detector

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    Avalanche photodiodes are widely used as practical detectors of single photons.1 Although conventional devices respond to one or more photons, they cannot resolve the number in the incident pulse or short time interval. However, such photon number resolving detectors are urgently needed for applications in quantum computing,2-4 communications5 and interferometry,6 as well as for extending the applicability of quantum detection generally. Here we show that, contrary to current belief,3,4 avalanche photodiodes are capable of detecting photon number, using a technique to measure very weak avalanches at the early stage of their development. Under such conditions the output signal from the avalanche photodiode is proportional to the number of photons in the incident pulse. As a compact, mass-manufactured device, operating without cryogens and at telecom wavelengths, it offers a practical solution for photon number detection.Comment: 12 pages, 4 figure

    Changes in liver mitochondrial plasticity induced by brain tumor

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    BACKGROUND: Accumulating data suggest that liver is a major target organ of systemic effects observed in the presence of a cancer. In this study, we investigated the consequences of the presence of chemically induced brain tumors in rats on biophysical parameters accounting for the dynamics of water in liver mitochondria. METHODS: Tumors of the central nervous system were induced by intraveinous administration of ethylnitrosourea (ENU) to pregnant females on the 19th day of gestation. The mitochondrial crude fraction was isolated from the liver of each animal and the dynamic parameters of total water and its macromolecule-associated fraction (structured water, H(2)Ost) were calculated from Nuclear Magnetic Resonance (NMR) measurements. RESULTS: The presence of a malignant brain tumor induced a loss of water structural order that implicated changes in the physical properties of the hydration shells of liver mitochondria macromolecules. This feature was linked to an increase in the membrane cholesterol content, a way to limit water penetration into the bilayer and then to reduce membrane permeability. As expected, these alterations in mitochondrial plasticity affected ionic exchanges and led to abnormal features of mitochondrial biogenesis and caspase activation. CONCLUSION: This study enlightens the sensitivity of the structured water phase in the liver mitochondria machinery to external conditions such as tumor development at a distant site. The profound metabolic and functional changes led to abnormal features of ion transport, mitochondrial biogenesis and caspase activation

    Shattered pellet injection experiments at JET in support of the ITER disruption mitigation system design

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    A series of experiments have been executed at JET to assess the efficacy of the newly installed shattered pellet injection (SPI) system in mitigating the effects of disruptions. Issues, important for the ITER disruption mitigation system, such as thermal load mitigation, avoidance of runaway electron (RE) formation, radiation asymmetries during thermal quench mitigation, electromagnetic load control and RE energy dissipation have been addressed over a large parameter range. The efficiency of the mitigation has been examined for the various SPI injection strategies. The paper summarises the results from these JET SPI experiments and discusses their implications for the ITER disruption mitigation scheme

    Testing a prediction model for the H-mode density pedestal against JET-ILW pedestals

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    The neutral ionisation model proposed by Groebner et al (2002 Phys. Plasmas 9 2134) to determine the plasma density profile in the H-mode pedestal, is extended to include charge exchange processes in the pedestal stimulated by the ideas of Mahdavi et al (2003 Phys. Plasmas 10 3984). The model is then tested against JET H-mode pedestal data, both in a 'standalone' version using experimental temperature profiles and also by incorporating it in the Europed version of EPED. The model is able to predict the density pedestal over a wide range of conditions with good accuracy. It is also able to predict the experimentally observed isotope effect on the density pedestal that eludes simpler neutral ionization models

    New H-mode regimes with small ELMs and high thermal confinement in the Joint European Torus

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    New H-mode regimes with high confinement, low core impurity accumulation, and small edge-localized mode perturbations have been obtained in magnetically confined plasmas at the Joint European Torus tokamak. Such regimes are achieved by means of optimized particle fueling conditions at high input power, current, and magnetic field, which lead to a self-organized state with a strong increase in rotation and ion temperature and a decrease in the edge density. An interplay between core and edge plasma regions leads to reduced turbulence levels and outward impurity convection. These results pave the way to an attractive alternative to the standard plasmas considered for fusion energy generation in a tokamak with a metallic wall environment such as the ones expected in ITER.& nbsp;Published under an exclusive license by AIP Publishing

    The role of ETG modes in JET-ILW pedestals with varying levels of power and fuelling

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    We present the results of GENE gyrokinetic calculations based on a series of JET-ITER-like-wall (ILW) type I ELMy H-mode discharges operating with similar experimental inputs but at different levels of power and gas fuelling. We show that turbulence due to electron-temperature-gradient (ETGs) modes produces a significant amount of heat flux in four JET-ILW discharges, and, when combined with neoclassical simulations, is able to reproduce the experimental heat flux for the two low gas pulses. The simulations plausibly reproduce the high-gas heat fluxes as well, although power balance analysis is complicated by short ELM cycles. By independently varying the normalised temperature gradients (omega(T)(e)) and normalised density gradients (omega(ne )) around their experimental values, we demonstrate that it is the ratio of these two quantities eta(e) = omega(Te)/omega(ne) that determines the location of the peak in the ETG growth rate and heat flux spectra. The heat flux increases rapidly as eta(e) increases above the experimental point, suggesting that ETGs limit the temperature gradient in these pulses. When quantities are normalised using the minor radius, only increases in omega(Te) produce appreciable increases in the ETG growth rates, as well as the largest increases in turbulent heat flux which follow scalings similar to that of critical balance theory. However, when the heat flux is normalised to the electron gyro-Bohm heat flux using the temperature gradient scale length L-Te, it follows a linear trend in correspondence with previous work by different authors
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