978 research outputs found
The effect of women’s care-giving role on their social security rights
Kitty Malherbe and Lorenzo Wakefield show how roles traditionally allotted to women may obstruct their access to the right to social security. There are instances where women’s care-giving role provides them with benefits they otherwise would not have had, such as child support grants.
On the other hand, care-giving can exclude women from the application of other benefits, such as certain retirement funds. The authors examine the need for measures aimed at providing assistance to women as care-givers as well as the potential pitfalls of such measures, such as the danger of stereotyping women as care-givers
Get Rid of Unanimity Rule: The Superiority of Majority Rules with Veto Power
We study unanimous decision making under incomplete information. We argue that all unanimous decision rules are not equivalent. We show that majority rules with veto power are (i) Pareto superior to commonly used unanimous rules, and (ii) ex-ante efficient in a broad class of situations
South African congenital disorders data, 2006 - 2014
Background. The National Department of Health in South Africa (SA) routinely collects congenital disorder (CD) data for its national CD surveillance system. The current system has been implemented since 2006, but no reports on the data collected, methodology, achievements or challenges have been published to date.Objectives. To ascertain the effectiveness of the current national CD surveillance system and its implementation.Method. A descriptive, retrospective study using an audit of the current database was undertaken to evaluate the number of notifications received, types of CDs reported and the quality of reporting across SA for data received from 2006 to 2014.Results. A total of 14 571 notifications were received, including 13 252 CDs and 1 319 zero notifications, across all nine provinces. Commonly reported CDs included Down syndrome, cleft lip and palate, talipes equinovarus, neural tube defects and albinism.Conclusions. The major challenges identified included erratic compliance by health facilities and a lack of healthcare providers trained in human genetics related to CDs. This has led to misdiagnosed and undiagnosed CDs, collectively resulting in under-reporting of cases by >98% during the review period. Owing to limited human and financial resources, it is recommended that the surveillance system be modified into an electronic format. This should be piloted alongside relevant training in specific sentinel sites, to improve data coverage and quality for further evaluation
Quasi full-disk maps of solar horizontal velocities using SDO/HMI data
For the first time, the motion of granules (solar plasma on the surface on
scales larger than 2.5 Mm) has been followed over the entire visible surface of
the Sun, using SDO/HMI white-light data.
Horizontal velocity fields are derived from image correlation tracking using
a new version of the coherent structure tracking algorithm.The spatial and
temporal resolutions of the horizontal velocity map are 2.5 Mm and 30 min
respectively .
From this reconstruction, using the multi-resolution analysis, one can obtain
to the velocity field at different scales with its derivatives such as the
horizontal divergence or the vertical component of the vorticity. The intrinsic
error on the velocity is ~0.25 km/s for a time sequence of 30 minutes and a
mesh size of 2.5 Mm.This is acceptable compared to the granule velocities,
which range between 0.3 km/s and 1.8 km/s. A high correlation between
velocities computed from Hinode and SDO/HMI has been found (85%). From the data
we derive the power spectrum of the supergranulation horizontal velocity field,
the solar differential rotation, and the meridional velocity.Comment: 8 pages, 11 figures, accepted in Astronomy and Astrophysic
Rejection-free Geometric Cluster Algorithm for Complex Fluids
We present a novel, generally applicable Monte Carlo algorithm for the
simulation of fluid systems. Geometric transformations are used to identify
clusters of particles in such a manner that every cluster move is accepted,
irrespective of the nature of the pair interactions. The rejection-free and
non-local nature of the algorithm make it particularly suitable for the
efficient simulation of complex fluids with components of widely varying size,
such as colloidal mixtures. Compared to conventional simulation algorithms,
typical efficiency improvements amount to several orders of magnitude
Coronal magnetic reconnection driven by CME expansion -- the 2011 June 7 event
Coronal mass ejections (CMEs) erupt and expand in a magnetically structured
solar corona. Various indirect observational pieces of evidence have shown that
the magnetic field of CMEs reconnects with surrounding magnetic fields,
forming, e.g., dimming regions distant from the CME source regions. Analyzing
Solar Dynamics Observatory (SDO) observations of the eruption from AR 11226 on
2011 June 7, we present the first direct evidence of coronal magnetic
reconnection between the fields of two adjacent ARs during a CME. The
observations are presented jointly with a data-constrained numerical
simulation, demonstrating the formation/intensification of current sheets along
a hyperbolic flux tube (HFT) at the interface between the CME and the
neighbouring AR 11227. Reconnection resulted in the formation of new magnetic
connections between the erupting magnetic structure from AR 11226 and the
neighboring active region AR 11227 about 200 Mm from the eruption site. The
onset of reconnection first becomes apparent in the SDO/AIA images when
filament plasma, originally contained within the erupting flux rope, is
re-directed towards remote areas in AR 11227, tracing the change of large-scale
magnetic connectivity. The location of the coronal reconnection region becomes
bright and directly observable at SDO/AIA wavelengths, owing to the presence of
down-flowing cool, dense (10^{10} cm^{-3}) filament plasma in its vicinity. The
high-density plasma around the reconnection region is heated to coronal
temperatures, presumably by slow-mode shocks and Coulomb collisions. These
results provide the first direct observational evidence that CMEs reconnect
with surrounding magnetic structures, leading to a large-scale re-configuration
of the coronal magnetic field.Comment: 12 pages, 12 figure
A Restricted Subset of Dendritic Cells Captures Airborne Antigens and Remains Able to Activate Specific T Cells Long after Antigen Exposure
AbstractMice sensitized for a Th2 response to Leishmania LACK antigen developed allergic airway inflammation upon exposure to LACK aerosol. Using multimers of I-Ad molecules bound to a LACK peptide as probes, we tracked the migration of LACK-specific Th2 cells to the airways. Elevated numbers of LACK-specific Th2 cells remained in the airways for 5 weeks after the last aerosol. Substantial numbers of DC presenting LACK peptides were found in the airways, but not in other compartments, for up to 8 weeks after antigen exposure. These LACK-presenting airway DC expressed CD11c and CD11b as well as high levels of surface molecules involved in uptake and costimulation. Taken together, our results may explain the chronic Th2 airway inflammation characteristic of allergic asthma
Scattering Theory of Non-Equilibrium Noise and Delta current fluctuations through a quantum dot
We consider the non-equilibrium zero frequency noise generated by a
temperature gradient applied on a device composed of two normal leads separated
by a quantum dot. We recall the derivation of the scattering theory for
non-equilibrium noise for a general situation where both a bias voltage and a
temperature gradient can coexist and put it in a historical perspective. We
provide a microscopic derivation of zero frequency noise through a quantum dot
based on a tight binding Hamiltonian, which constitutes a generalization of the
pioneering work of Caroli et al. for the current obtained in the context of the
Keldysh formalism. For a single level quantum dot, the obtained transmission
coefficient entering the scattering formula for the non-equilibrium noise
corresponds to a Breit-Wigner resonance. We compute the delta- noise as a
function of the dot level position, and of the dot level width, in the
Breit-Wigner case, for two relevant situations which were considered recently
in two separate experiments. In the regime where the two reservoir temperatures
are comparable, our gradient expansion shows that the delta- noise is
dominated by its quadratic contribution, and is minimal close to resonance. In
the opposite regime where one reservoir is much colder, the gradient expansion
fails and we find the noise to be typically linear in temperature before
saturating. In both situations, we conclude with a short discussion of the case
where both a voltage bias and a temperature gradient are present, in order to
address the potential competition with thermoelectric effects.Comment: 19 pages, 9 figure
South African congenital disorders data, 2006 - 2014
Background. The National Department of Health in South Africa (SA) routinely collects congenital disorder (CD) data for its national CD surveillance system. The current system has been implemented since 2006, but no reports on the data collected, methodology, achievements or challenges have been published to date.Objectives. To ascertain the effectiveness of the current national CD surveillance system and its implementation.Method. A descriptive, retrospective study using an audit of the current database was undertaken to evaluate the number of notifications received, types of CDs reported and the quality of reporting across SA for data received from 2006 to 2014.Results. A total of 14Â 571 notifications were received, including 13 252 CDs and 1 319 zero notifications, across all nine provinces. Commonly reported CDs included Down syndrome, cleft lip and palate, talipes equinovarus, neural tube defects and albinism.Conclusions. The major challenges identified included erratic compliance by health facilities and a lack of healthcare providers trained in human genetics related to CDs. This has led to misdiagnosed and undiagnosed CDs, collectively resulting in under-reporting of cases by >98% during the review period. Owing to limited human and financial resources, it is recommended that the surveillance system be modified into an electronic format. This should be piloted alongside relevant training in specific sentinel sites, to improve data coverage and quality for further evaluation
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