335 research outputs found
Sexual violence in post-conflict Liberia: survivors and their care.
Using routine data from three clinics offering care to survivors of sexual violence (SV) in Monrovia, Liberia, we describe the characteristics of SV survivors and the pattern of SV and discuss how the current approach could be better adapted to meet survivors' needs. There were 1500 survivors seeking SV care between January 2008 and December 2009. Most survivors were women (98%) and median age was 13âyears (Interquartile range: 9-17âyears). Sexual aggression occurred during day-to-day activities in 822 (55%) cases and in the survivor's home in 552 (37%) cases. The perpetrator was a known civilian in 1037 (69%) SV events. Only 619 (41%) survivors sought care within 72âh. The current approach could be improved by: effectively addressing the psychosocial needs of child survivors, reaching male survivors, targeting the perpetrators in awareness and advocacy campaigns and reducing delays in seeking care
A comparison of incompressible limits for resistive plasmas
The constraint of incompressibility is often used to simplify the
magnetohydrodynamic (MHD) description of linearized plasma dynamics because it
does not affect the ideal MHD marginal stability point. In this paper two
methods for introducing incompressibility are compared in a cylindrical plasma
model: In the first method, the limit is taken, where
is the ratio of specific heats; in the second, an anisotropic mass
tensor is used, with the component parallel to the magnetic
field taken to vanish, . Use of resistive MHD reveals
the nature of these two limits because the Alfv\'en and slow magnetosonic
continua of ideal MHD are converted to point spectra and moved into the complex
plane. Both limits profoundly change the slow-magnetosonic spectrum, but only
the second limit faithfully reproduces the resistive Alfv\'en spectrum and its
wavemodes. In ideal MHD, the slow magnetosonic continuum degenerates to the
Alfv\'en continuum in the first method, while it is moved to infinity by the
second. The degeneracy in the first is broken by finite resistivity. For
numerical and semi-analytical study of these models, we choose plasma
equilibria which cast light on puzzling aspects of results found in earlier
literature.Comment: 14 pages, 10 figure
Turbulent Mixing in the Surface Layers of Accreting Neutron Stars
During accretion a neutron star (NS) is spun up as angular momentum is
transported through its surface layers. We study the resulting differentially
rotating profile, focusing on the impact this has for type I X-ray bursts. The
predominant viscosity is likely provided by the Tayler-Spruit dynamo. The
radial and azimuthal magnetic field components have strengths of ~10^5 G and
~10^10 G, respectively. This leads to nearly uniform rotation at the depths of
interest for X-ray bursts. A remaining small shear transmits the accreted
angular momentum inward to the NS interior. Though this shear gives little
viscous heating, it can trigger turbulent mixing. Detailed simulations will be
required to fully understand the consequences of mixing, but our models
illustrate some general features. Mixing has the greatest impact when the
buoyancy at the compositional discontinuity between accreted matter and ashes
is overcome. This occurs at high accretion rates, at low spin frequencies, or
may depend on the ashes from the previous burst. We then find two new regimes
of burning. The first is ignition in a layer containing a mixture of heavier
elements from the ashes. If ignition occurs at the base of the mixed layer,
recurrence times as short as ~5-30 minutes are possible. This may explain the
short recurrence time of some bursts, but incomplete burning is still needed to
explain these bursts' energetics. When mixing is sufficiently strong, a second
regime is found where accreted helium mixes deep enough to burn stably,
quenching X-ray bursts. We speculate that the observed change in X-ray burst
properties near one-tenth the Eddington accretion rate is from this mechanism.
The carbon-rich material produced by stable helium burning would be important
for triggering and fueling superbursts. (abridged)Comment: Accepted for publication in The Astrophysical Journal, 16 pages, 15
figure
Structure, Deformations and Gravitational Wave Emission of Magnetars
Neutron stars can have, in some phases of their life, extremely strong
magnetic fields, up to 10^15-10^16 G. These objects, named magnetars, could be
powerful sources of gravitational waves, since their magnetic field could
determine large deformations. We discuss the structure of the magnetic field of
magnetars, and the deformation induced by this field. Finally, we discuss the
perspective of detection of the gravitational waves emitted by these stars.Comment: 11 pages, 2 figures, prepared for 19th International Conference on
General Relativity and Gravitation (GR19), Mexico City, Mexico, July 5-9,
201
On non-axisymmetric magnetic equilibria in stars
In previous work stable approximately axisymmetric equilibrium configurations
for magnetic stars were found by numerical simulation. Here I investigate the
conditions under which more complex, non-axisymmetric configurations can form.
I present numerical simulations of the formation of stable equilibria from
turbulent initial conditions and demonstrate the existence of non-axisymmetric
equilibria consisting of twisted flux tubes lying horizontally below the
surface of the star, meandering around the star in random patterns. Whether
such a non-axisymmetric equilibrium or a simple axisymmetric equilibrium forms
depends on the radial profile of the strength of the initial magnetic field.
The results could explain observations of non-dipolar fields on stars such as
the B0.2 main-sequence star tau-Sco or the pulsar 1E 1207.4-5209. The secular
evolution of these equilibria due to Ohmic and buoyancy processes is also
examined.Comment: 13 pages, 12 figures. Accepted by MNRA
Managing and monitoring chronic non-communicable diseases in a primary health care clinic, Lilongwe, Malawi.
SETTING: Patients with chronic non-communicable diseases attending a primary health care centre, Lilongwe, Malawi. OBJECTIVE: Using an electronic medical record monitoring system, to describe the quarterly and cumulative disease burden, management and outcomes of patients registered between March 2014 and June 2015. DESIGN: A cross-sectional study. RESULTS: Of 1135 patients, with new registrations increasing each quarter, 66% were female, 21% were aged â©Ÿ65 years, 20% were obese, 53% had hypertension alone, 18% had diabetes alone, 12% had asthma, 10% had epilepsy and 7% had both hypertension and diabetes. In every quarter, about 30% of patients did not attend the clinic and 19% were registered as lost to follow-up (not seen for â©Ÿ1 year) in the last quarter. Of those attending, over 90% were prescribed medication, and 80-90% with hypertension and/or diabetes had blood pressure/blood glucose measured. Over 85% of those with epilepsy had no seizures and 60-75% with asthma had no severe attacks. Control of blood pressure (41-51%) and diabetes (15-38%) was poor. CONCLUSION: It is feasible to manage patients with non-communicable diseases in a primary health care setting in Malawi, although more attention is needed to improve clinic attendance and the control of hypertension and diabetes
X-rays in the Orion Nebula Cluster: Constraints on the origins of magnetic activity in pre-main sequence stars
A recent Chandra/ACIS observation of the Orion Nebula Cluster detected 1075
sources (Feigelson et al. 2002), providing a uniquely large and well-defined
sample to study the dependence of magnetic activity on bulk properties for
stars descending the Hayashi tracks. The following results are obtained: (1)
X-ray luminosities L_t in the 0.5-8 keV band are strongly correlated with
bolometric luminosity with = -3.8 for stars with masses 0.7<M<2
Mo, an order of magnitude below the main sequence saturation level; (2) the
X-ray emission drops rapidly below this level in some or all stars with 2<M<3
Mo; (3) the presence or absence of infrared circumstellar disks has no apparent
relation to X-ray levels; and (4) X-ray luminosities exhibit a slight rise as
rotational periods increase from 0.4 to 20 days. This last finding stands in
dramatic contrast to the strong anticorrelation between X-rays and period seen
in main sequence stars.
The absence of a strong X-ray/rotation relationship in PMS stars, and
particularly the high X-ray values seen in some very slowly rotating stars, is
a clear indication that the mechanisms of magnetic field generation differ from
those operating in main sequence stars. The most promising possibility is a
turbulent dynamo distributed throughout the deep convection zone, but other
models such as alpha-Omega dynamo with `supersaturation' or relic core fields
are not immediately excluded. The drop in magnetic activity in
intermediate-mass stars may reflect the presence of a significant radiative
core. The evidence does not support X-ray production in large-scale star-disk
magnetic fields.Comment: 51 pages, 8 figures. To appear in the Astrophysical Journa
A Prospective Randomized Clinical Trial to Assess Antibiotic Pocket Irrigation on Tissue Expander Breast Reconstruction
Bacterial infection is the most common complication following staged post-mastectomy breast reconstruction initiated with a tissue expander (TE). to limit bacterial infection, antibiotic irrigation of the surgical site is commonly performed despite little high-quality data to support this practice. We performed a prospective randomized control trial to compare the impact of saline irrigation alone to a triple antibiotic irrigation regimen (1 g cefazolin, 80 mg gentamicin, and 50,000 units of bacitracin in 500 mL of saline) for breast implant surgery. The microbiome in breasts with cancer
Shifts in risk sensitivity and resource availability alter fat stores for a large mammal following extreme winter conditions
For species that inhabit environments where resource availability may be unpredictable, balance of resource allocation to life-history traits can have heightened consequences for survival, reproduction, and ultimately, fitness. Acquisition and allocation of energy to maintenance, capital gain and reproduction should be in tune with the landscape an animal inhabitsâenvironmental severity, food availability and population size all influence the resources animals have and dictate the ways they should be allocated. In seasonal environments, animals that experience periods of extreme resource limitation (e.g. harsh winters) may favour allocation of resources to body reserves to secure their survival at the cost of reproduction (i.e. risk averse). In contrast, the same accumulation of body reserves may not be necessary to survive in relatively benign landscapes where instead, allocation to reproduction is favoured (i.e. risk prone). According to the theory of risk-sensitive allocation of resources, when animals are exposed to unprecedented or life-threatening conditions, they may shift resource allocation to favour building capital over allocation in reproduction to preempt against encountering another life-threatening event in the future. Using data from a long-term project on a highly site-faithful and long-lived species, mule deer (Odocoileus hemionus), we evaluated how a life-threatening winter and the associated changes in resource availability resulting from a population reduction influenced how animals acquired and allocated energy to survival (i.e. fat accumulation). Per capita precipitation, and the associated reduction in population abundance after the severe winter, had a positive influence of accrual of fat over summer. After the extreme physiological stress of a hard winter, deer starting spring with low body reserves accumulated 2.8 percentage points more fat over summer compared with before the experience of a bad winter and had an increased probability of recruiting fewer offspring. Fat stores can interact with environment, life history and behaviour to influence survival during periods of resource scarcity. For a long-lived herbivore, we documented shifts in risk tolerance associated with fat accrual in preparation for winter, supporting the notion that risk-sensitive allocation of resources may be plasticâan essential adaptation for animals to cope with rapidly changing landscapes.publishedVersio
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