144 research outputs found
Do saving promotion interventions help alleviate poverty in Sub-Saharan Africa? A systematic review and meta-analysis
Saving promotion interventions have gained momentum in international development over the recent years. Our analysis investigates whether saving promotion can effectively reduce poverty and economic hardship in Sub-Saharan Africa. In an extensive database search, 9330 records were screened and 27 randomised controlled trials on saving promotion interventions fulfilled the inclusion criteria. Robust-variance estimations of pooled effect sizes show small but significant impacts on poverty reduction, including increases in household expenditures and incomes, higher returns from family businesses, and improved food security. They also show positive impacts on more intermediate outcomes including total savings, pro-saving attitudes, financial literacy, and investments in small-scale family businesses. Our results do not show significant effects on assets, housing quality, education, or health. Findings from this analysis suggest that saving promotion schemes are highly relevant in reducing poverty in Sub-Saharan Africa, and that formal banking services in particular require adaptation to the needs of the poor
On string solutions of Bethe equations in N=4 supersymmetric Yang-Mills theory
The Bethe equations, arising in description of the spectrum of the dilatation
operator for the su(2) sector of the N=4 supersymmetric Yang-Mills theory, are
considered in the anti-ferromagnetic regime. These equations are deformation of
those for the Heisenberg XXX magnet. It is proven that in the thermodynamic
limit roots of the deformed equations group into strings. It is proven that the
corresponding Yang's action is convex, which implies uniqueness of solution for
centers of the strings. The state formed of strings of length (2n+1) is
considered and the density of their distribution is found. It is shown that the
energy of such a state decreases as n grows. It is observed that
non-analyticity of the left hand side of the Bethe equations leads to an
additional contribution to the density and energy of strings of even length.
Whence it is concluded that the structure of the anti-ferromagnetic vacuum is
determined by the behaviour of exponential corrections to string solutions in
the thermodynamic limit and possibly involves strings of length 2.Comment: LaTex, 9 pages, 1 figur
Predictors of internalised HIV-related stigma: a systematic review of studies in sub-Saharan Africa
This systematic review aims to synthesise evidence on predictors of internalised HIV stigma amongst people living with HIV in sub-Saharan Africa. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were used. Studies were identified through electronic databases, grey literature, reference harvesting and contacts with key researchers. Quality of findings was assessed through an adapted version of the Cambridge Quality Checklists. A total of 590 potentially relevant titles were identified. Seventeen peer-reviewed articles and one draft book chapter were included. Studies investigated socio-demographic, HIV-related, intra-personal and interpersonal correlates of internalised stigma. Eleven articles used cross-sectional data, six articles used prospective cohort data and one used both prospective cohort and cross-sectional data to assess correlates of internalised stigma. Poor HIV-related health weakly predicted increases in internalised HIV stigma in three longitudinal studies. Lower depression scores and improvements in overall mental health predicted reductions in internalised HIV stigma in two longitudinal studies, with moderate and weak effects, respectively. No other consistent predictors were found. Studies utilising analysis of change and accounting for confounding factors are necessary to guide policy and programming but are scarce. High-risk populations, other stigma markers that might layer upon internalised stigma, and structural drivers of internalised stigma need to be examined
Non-planar ABJM Theory and Integrability
Using an effective vertex method we explicitly derive the two-loop dilatation
generator of ABJM theory in its SU(2)xSU(2) sector, including all non-planar
corrections. Subsequently, we apply this generator to a series of finite length
operators as well as to two different types of BMN operators. As in N=4 SYM, at
the planar level the finite length operators are found to exhibit a degeneracy
between certain pairs of operators with opposite parity - a degeneracy which
can be attributed to the existence of an extra conserved charge and thus to the
integrability of the planar theory. When non-planar corrections are taken into
account the degeneracies between parity pairs disappear hinting the absence of
higher conserved charges. The analysis of the BMN operators resembles that of
N=4 SYM. Additional non-planar terms appear for BMN operators of finite length
but once the strict BMN limit is taken these terms disappear.Comment: 1+26 pages, uses axodraw.sty. v2: typos fixed, references added. v3:
more typos fixed, minor correction
Finite size giant magnons in the SU(2) x SU(2) sector of AdS_4 x CP^3
We use the algebraic curve and Luscher's mu-term to calculate the leading
order finite size corrections to the dispersion relation of giant magnons in
the SU(2) x SU(2) sector of AdS_4 x CP^3. We consider a single magnon as well
as one magnon in each SU(2). In addition the algebraic curve computation is
generalized to give the leading order correction for an arbitrary multi-magnon
state in the SU(2) x SU(2) sector.Comment: 19 pages; v2, v3: references added, typos fixe
Quantum folded string and integrability: from finite size effects to Konishi dimension
Using the algebraic curve approach we one-loop quantize the folded string
solution for the type IIB superstring in AdS(5)xS(5). We obtain an explicit
result valid for arbitrary values of its Lorentz spin S and R-charge J in terms
of integrals of elliptic functions. Then we consider the limit S ~ J ~ 1 and
derive the leading three coefficients of strong coupling expansion of short
operators. Notably, our result evaluated for the anomalous dimension of the
Konishi state gives 2\lambda^{1/4}-4+2/\lambda^{1/4}. This reproduces correctly
the values predicted numerically in arXiv:0906.4240. Furthermore we compare our
result using some new numerical data from the Y-system for another similar
state. We also revisited some of the large S computations using our methods. In
particular, we derive finite--size corrections to the anomalous dimension of
operators with small J in this limit.Comment: 20 pages, 1 figure; v2: references added, typos corrected; v3: major
improvement of the references; v4: Discussion of short operators is
restricted to the case n=1. This restriction does not affect the main results
of the pape
Semiclassical strings in AdS(3) X S^2
In this paper, we investigate the semiclassical strings in AdS(3)XS^2, in
which the string configuration of AdS(3) is classified to three cases depending
on the parameters. Each of these has a different anomalous dimension
proportional to logS, S^(1/3) and S, where S is a angular momentum on AdS(3).
Further we generalize the dispersion relations for various string configuration
on AdS(3)XS^2.Comment: 15 pages, added reference
The all loop AdS4/CFT3 Bethe ansatz
We propose a set of Bethe equations yielding the full asymptotic spectrum of
the AdS4/CFT3 duality proposed in arXiv:0806.1218 to all orders in the t'Hooft
coupling. These equations interpolate between the 2-loop Bethe ansatz of
Minahan and Zarembo arXiv:0806.3951 and the string algebraic curve of
arXiv:0807.0437. The several SU(2|2) symmetries of the theory seem to highly
constrain the form of the Bethe equations up to a dressing factor whose form we
also conjecture.Comment: References added. Factor of 2 in the discussion of the (generalized)
scaling function fixe
Parenting, mental health and economic pathways to prevention of violence against children in South Africa.
BACKGROUND: Parenting programs based on social learning theory have increasing empirical evidence for reducing violence against children. Trials are primarily from high-income countries and with young children. Globally, we know little about how parenting programs work to reduce violence, with no known studies in low or middle-income countries (LMICs). This study examines mechanisms of change of a non-commercialized parenting program, Parenting for Lifelong Health for Teens, designed with the World Health Organization and UNICEF. A cluster randomized trial showed main effects on parenting and other secondary outcomes. We conducted secondary analysis of trial data to investigate five potential mediators of reduced violence against children: improved parenting, adolescent behaviour, caregiver mental health, alcohol/drug avoidance, and family economic strengthening. METHODS: The trial was implemented in rural South Africa with 40 sites, n = 552 family dyads (including adolescents aged 10-18 and primary caregivers). Intervention sites (n = 20) received the 14-session parenting program delivered by local community members, including modules on family budgeting and savings. Control sites (n = 20) received a brief informational workshop. Emotional and physical violence against children/adolescents and each potential mediator were reported by adolescents and caregivers at baseline and 9-13 months post-randomisation. Structural equation modelling was used to test simultaneous hypothesized pathways to violence reduction. RESULTS: Improvements in four pathways mediated reduced violence against children: 1) improved parenting practices, 2) improved caregiver mental health (reduced depression), 3) increased caregiver alcohol/drug avoidance and 4) improved family economic welfare. Improved child behaviour was not a mediator, although it was associated with less violence. CONCLUSIONS: Simultaneously bolstering a set of family processes can reduce violence. Supporting self-care and positive coping for caregivers may be essential in challenging contexts. In countries with minimal or no economic safety nets, linking social learning parenting programs with economic strengthening skills may bring us closer to ending violence against children
Quorum-sensing
The agr quorum-sensing system links Staphylococcus aureus metabolism to virulence, in part by increasing bacterial survival during exposure to lethal concentrations of H2O2, a crucial host defense against S. aureus. We now report that protection by agr surprisingly extends beyond post-exponential growth to the exit from stationary phase when the agr system is no longer turned on. Thus, agr can be considered a constitutive protective factor. Deletion of agr resulted in decreased ATP levels and growth, despite increased rates of respiration or fermentation at appropriate oxygen tensions, suggesting that Îagr cells undergo a shift towards a hyperactive metabolic state in response to diminished metabolic efficiency. As expected from increased respiratory gene expression, reactive oxygen species (ROS) accumulated more in the agr mutant than in wild-type cells, thereby explaining elevated susceptibility of Îagr strains to lethal H2O2 doses. Increased survival of wild-type agr cells during H2O2 exposure required sodA, which detoxifies superoxide. Additionally, pretreatment of S. aureus with respiration-reducing menadione protected Îagr cells from killing by H2O2. Thus, genetic deletion and pharmacologic experiments indicate that agr helps control endogenous ROS, thereby providing resilience against exogenous ROS. The long-lived \u27memory\u27 of agr-mediated protection, which is uncoupled from agr activation kinetics, increased hematogenous dissemination to certain tissues during sepsis in ROS-producing, wild-type mice but not ROS-deficient (Cybb-/-) mice. These results demonstrate the importance of protection that anticipates impending ROS-mediated immune attack. The ubiquity of quorum sensing suggests that it protects many bacterial species from oxidative damage
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