456 research outputs found
VVF Treatment and Training through Outreach Services: AMREF Experience
Background: In the rural areas, where the obstetric services are poor, where the woman has no say over her own body and pregnancy, where the husband and the family decide, what will happen with her? AMREF did a study and found that less than 15% of the referred patients in actual factreach the referral hospital. For almost 50 years, (Flying Doctors Service) has been visiting remote government and mission hospitals all over Eastern Africa to bring specialist medical services to the sick.Methods: Over 100 hospitals are visited each once to six times a year. This service is done by plane: Since most hospitals are in the rural areas, the AMREF plane carries up to 6 or more specialists and drops them in different places. In 1992 VVF-repair was included in the specialist services. During the visits, Genuinely interested doctors got hands on training while the nurses received training in the pre-operative, perioperativeand postoperative management of OF. Trained specialists take part in the Specialists Outreach Program and operate and train on their own.Results: In 2004 over 1300 VVF/RVF-repairs and related operations were performed in Eastern Africa by AMREF and AMREF trained specialists with 1 visiting English gynaecologist. All the trained local specialists are performing VVF repairs.Conclusions: Fistula treatment through Outreach Services preferably by plane and Training and continuing training (apprenticeship) works well. Almost all trained specialists continue repairing fistulas. The Way Forward is to train more personnel, especially in underserved area
Line absorption of He-like triplet lines by Li-like ions. Caveats of using line ratios of triplets for plasma diagnostics
He-like ions produce distinctive series of triplet lines under various
astrophysical conditions. However, this emission can be affected by line
absorption from Li-like ions in the same medium. We investigate this absorption
of He-like triplets and present the implications for diagnostics of plasmas in
photoionisation equilibrium using the line ratios of the triplets. Our
computations were carried out for the O VI and Fe XXIV absorption of the O VII
and Fe XXV triplet emission lines, respectively. The fluorescent emission by
the Li-like ions and continuum absorption of the He-like ion triplet lines are
also investigated. We determine the absorption of the triplet lines as a
function of Li-like ion column density and velocity dispersion of the emitting
and absorbing medium. We find O VI line absorption can significantly alter the
O VII triplet line ratios in optically-thin plasmas, by primarily absorbing the
intercombination lines, and to a lesser extent, the forbidden line. Because of
intrinsic line absorption by O VI inside a photoionised plasma, the predicted
ratio of forbidden to intercombination line intensity for the O VII triplet
increases from 4 up to an upper limit of 16. This process can explain the
triplet line ratios that are higher than expected and that are seen in some
X-ray observations of photoionised plasmas. For the Fe XXV triplet, line
absorption by Fe XXIV becomes less apparent owing to significant fluorescent
emission by Fe XXIV. Without taking the associated Li-like ion line absorption
into account, the density diagnosis of photoionised plasmas using the observed
line ratios of the He-like ion triplet emission lines can be unreliable,
especially for low-Z ions.Comment: Accepted for publication in Astronomy & Astrophysics, 6 pages, 4
figure
The X-ray spectra of the flaring and quiescent states of YZ CMi observed by XMM-Newton
We analyse the X-ray spectrum of the active late-type star YZ CMi (M4.5V); for quiescent as well as active stages, we derive emission measure (EM) distributions, elemental abundances, and electron temperatures and densities, which are in turn used to estimate flare loop lengths as well as coronal magnetic field strengths. YZ CMi was observed in the wavelength range 1-40 Å by the X-ray detectors RGS, EPIC-MOS and EPIC-pn onboard XMM-Newton. Some flares occurred during the observation. We perform a multi-temperature fit and model the differential EM of both the flaring and the quiescent parts of the spectrum and derive the coronal temperature distribution, EMs, and elemental abundances of the flaring and quiescent states. The observed temperature covers a range from about 1.3 to 42 MK. The total volume EM in this temperature interval is 13.7 ± .8 × 1050 cm−3 for the quiescent state and 21.7 ± 1.4 × 1050 cm−3 for the active state. The abundance pattern in the quiescent state shows some depletion of low first ionization potential (FIP) elements relative to high-FIP elements, indicating the presence of an I(nverse)FIP effect in this active star. No abundance differences between the quiescent and the active states are established. Based on the X-ray light curves in combination with the temperature, density and EM, the coronal magnetic field strength at flare-site is found to be between 50 and 100 G and the flaring loop lengths are estimated to be in the range of 5 -13 × 109 c
Estimating turbulent velocities in the elliptical galaxies NGC 5044 and NGC 5813
The interstellar and intra-cluster medium in giant elliptical galaxies and
clusters of galaxies is often assumed to be in hydrostatic equilibrium.
Numerical simulations, however, show that about 5-30% of the pressure in a
cluster is provided by turbulence induced by, for example, the central AGN and
merger activity. We aim to put constraints on the turbulent velocities and
turbulent pressure in the ICM of the giant elliptical galaxies NGC 5044 and NGC
5813 using XMM-Newton RGS observations. The magnitude of the turbulence is
estimated using the Fe XVII lines at 15.01 A, 17.05 A, and 17.10 A in the RGS
spectra. At low turbulent velocities, the gas becomes optically thick in the
15.01 A line due to resonant scattering, while the 17 A lines remain optically
thin. By comparing the (I(17.05)+I(17.10))/I(15.01) line ratio from RGS with
simulated line ratios for different Mach numbers, the level of turbulence is
constrained. The measurement is limited by systematic uncertainties in the
atomic data, which are at the 20-30% level. We find that the line ratio in NGC
5813 is significantly higher than in NGC 5044. This difference can be explained
by a higher level of turbulence in NGC 5044. The high turbulent velocities and
the fraction of the turbulent pressure support of >40% in NGC 5044, assuming
isotropic turbulence, confirm that it is a highly disturbed system, probably
due to an off-axis merger. The turbulent pressure support in NGC 5813 is more
modest at 15-45%. The (I(17.05)+I(17.10))/I(15.01) line ratio in an optically
thin plasma, calculated using AtomDB v2.0.1, is 2 sigma above the ratio
measured in NGC 5044, which cannot be explained by resonant scattering. This
shows that the discrepancies between theoretical, laboratory, and astrophysical
data on Fe XVII lines need to be reduced to improve the accuracy of the
determination of turbulent velocities using resonant scattering.Comment: 11 pages, 5 figures, accepted for publication in A&
A Study of the Coronal Plasma in RS CVn binary systems
XMM-Newton has been performing comprehensive studies of X-ray bright RS CVn
binaries in its Calibration and Guaranteed Time programs. We present results
from ongoing investigations in the context of a systematic study of coronal
emission from RS CVns. We concentrate in this paper on coronal abundances and
investigate the abundance pattern in RS CVn binaries as a function of activity
and average temperature. A transition from an Inverse First Ionization
Potential (FIP) effect towards an absence of a clear trend is found in
intermediately active RS CVn systems. This scheme corresponds well into the
long-term evolution from an IFIP to a FIP effect found in solar analogs. We
further study variations in the elemental abundances during a large flare.Comment: to appear in The Twelfth Cool Stars, Stellar Systems and the Sun,
eds. A. Brown, T.R. Ayres, G.M. Harper, (Boulder: Univ. of Colorado), in
pres
Wavelengths and Energy Levels of the Upper Levels of Singly Ionized Nickel (Ni ii) from 3<i>d</i><sup>8</sup>(<sup>3</sup><i>F</i>)5<i>f</i> to 3d<sup>8</sup>(<sup>3</sup><i>F)</i>9<i>s</i>
Using high-resolution spectra of Ni ii recorded using Fourier transform (FT) spectroscopy of continuous, nickel-helium hollow cathode discharge sources in the region 143-5555 nm (1800-70,000 cm−1, the analysis of 1016 Ni ii lines confirmed and optimized 206 previously reported energy levels of the (3 F) parent term, from 3d 8(3 F)5f to 3d 8(3 F)9s, lying between 122,060 and 138,563 cm−1. The uncertainties of these levels have been improved by at least an order of magnitude compared with their previously reported values. With the increased resolution and spectral range of the FT measurements, compared to previously published grating spectra, we were able to extend our analysis to identify and establish 33 new energy levels of Ni ii, which are reported here for the first time. Eigenvector compositions of all revised and newly established energy levels were calculated using the orthogonal operator method. In addition, an improved ionization energy of 146,541.35 ± 0.15 cm−1 for Ni ii, using highly excited levels of the 3d 8(3 F)5g, 3d 8(3 F)6g, and 3d 8(3 F)6h configurations, has been derived.</p
Hot and cool: two emission-line stars with constrasting behaviours in the same XMM-Newton field
High-energy emissions are good indicators of peculiar behaviours in stars. We
have therefore obtained an XMM-Newton observation of HD155806 and
1RXSJ171502.4-333344, and derived their spectral properties for the first time.
The X-ray spectrum of HD155806 appears soft, even slightly softer than usual
for O-type stars (as shown by a comparison with the O9 star HD155889 in the
same XMM field). It is well-fitted with a two-component thermal model with low
temperatures (0.2 and 0.6 keV), and it shows no overluminosity
(log[LX/Lbol]=-6.75). The high-resolution spectrum, though noisy, reveals a few
broad, symmetric X-ray lines (FWHM ~ 2500 km/s). The X-ray emission is
compatible with the wind-shock model and therefore appears unaffected by the
putative dense equatorial regions at the origin of the Oe classification.
1RXSJ171502.4-333344 is a nearby flaring source of moderate X-ray luminosity
(log[LX/Lbol]=-3), with a soft thermal spectrum composed of narrow lines and
presenting a larger abundance of elements (e.g. Ne) with a high first
ionization potential (FIP) compared to lower-FIP elements. All the evidence
indicates a coronal origin for the X-ray emission, in agreement with the dMe
classification of this source.Comment: 8 pages, 6 figures, including annex ; accepted for publication by A&
Relationship between X-ray and ultraviolet emission of flares from dMe stars observed by XMM-Newton
We present simultaneous ultraviolet and X-ray observations of the dMe-type
flaring stars AT Mic, AU Mic, EV Lac, UV Cet and YZ CMi obtained with the
XMM-Newton observatory. During 40 hours of simultaneous observation we identify
13 flares which occurred in both wave bands. For the first time, a correlation
between X-ray and ultraviolet flux for stellar flares has been observed. We
find power-law relationships between these two wavelength bands for the flare
luminosity increase, as well as for flare energies, with power-law exponents
between 1 and 2. We also observe a correlation between the ultraviolet flare
energy and the X-ray luminosity increase, which is in agreement with the
Neupert effect and demonstrates that chromospheric evaporation is taking place.Comment: 8 pages, 4 figures, 3 tables, accepted by A&A (30 Sept. 2004
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