6,636 research outputs found
Advancing Peacebuilding from the Ground up
For many years, scholars and practitioners have been struggling with problems of local ownership in international organizations-led peacebuilding. Despite the discourse surrounding giving ownership to local communities, top-down approaches prevail in practice and often lead to counterproductive outcomes. Ethnographic fieldwork has proven that international organizsations could achieve a better understanding of local experiential perspectives on conflict and peace. Here, we point to key features of local peace and suggest how international organizations could better incorporate peaceful local agency, cope with power imbalances and advance strategies for peacebuilding from the ground up
Phase I of the DiaVACCS screening trial: Study design, methods, population demographics and baseline results
Background. Human papillomavirus (HPV)-based primary screening guidelines are based on screening test performance and prevalence data generated in high-resource areas with low HIV infection rates. There is an urgent need for local data on infection and disease prevalence, as well as screening test performance, among both HIV-positive and HIV-negative South African (SA) women, in order to inform updated screening guidelines. Objectives. This study describes the baseline characteristics of participants in the cross-sectional phase of the multicentric DIAgnosis in Vaccine And Cervical Cancer Screen (DiaVACCS) screening trial. The objective was to determine the prevalence of positive screening and pre-invasive disease using different tests and strategies in the SA HIV-positive and HIV-negative population.Methods. A total of 1 104 women aged 25 - 65 years and eligible for screening were included, 465 HIV positive and 639 HIV negative. Visual inspection and molecular and cytological screening tests were done on self-sampled and healthcare worker-collected specimens. All participants who screened positive and 49.1% of those who screened negative were invited for colposcopy and biopsy, and those qualifying for treatment were recalled for large loop excision of the transformation zone as part of the trial. The worst histology result for each participant was used, and for untested women, multiple imputation was used to estimate verification biasadjusted histology values.Results. Visual inspection was positive in 50.4% of HIV-positive v. 20.9% of HIV-negative women, cytology (atypical squamous cells of undetermined significance) in 39.9% v. 17.0%, and high-risk HPV DNA in 41.2% v. 19.6%. Overall, high-grade squamous intraepithelial lesion-positive cytology peaked in the age group 30 - 39 years at 16.7%. After adjustment for verification bias, histological diagnosis of cervical intraepithelial neoplasia (CIN)2+ was suspected in 44.7% v. 23.5% and CIN3+ in 23.3% v. 10.2% of HIV-positive and negative women, respectively. Invasive cancer was diagnosed in 15 women (1.95% of histological studies performed), and verification bias adjustment suggested 20 cases (1.8% of the study population).Conclusion. The baseline findings from the DiaVACCS trial confirm a high prevalence of HPV-related cervical pathology in the SA HIV-negative screening population, showing a clear need to reach these women with a screening programme. Among HIV-positive women, prevalence values were almost doubled. The prevalence of existing invasive cervical cancer was 1 - 2% of all women. Further analysis of the performance of single and multiple screening tests between the two subgroups will contribute to the choice of the most effective strategies to identify women at risk of developing invasive cancer
Action minimizing fronts in general FPU-type chains
We study atomic chains with nonlinear nearest neighbour interactions and
prove the existence of fronts (heteroclinic travelling waves with constant
asymptotic states). Generalizing recent results of Herrmann and Rademacher we
allow for non-convex interaction potentials and find fronts with non-monotone
profile. These fronts minimize an action integral and can only exists if the
asymptotic states fulfil the macroscopic constraints and if the interaction
potential satisfies a geometric graph condition. Finally, we illustrate our
findings by numerical simulations.Comment: 19 pages, several figure
Radiative capture rates at deep defects from electronic structure calculations
We present a methodology to calculate radiative carrier capture coefficients
at deep defects in semiconductors and insulators from first principles.
Electronic structure and lattice relaxations are accurately described with
hybrid density functional theory. Calculations of capture coefficients provide
an additional validation of the accuracy of these functionals in dealing with
localized defect states. We also discuss the validity of the Condon
approximation, showing that even in the event of large lattice relaxations the
approximation is accurate. We test the method on
GaAs:- and GaN:C, for which
reliable experiments are available, and demonstrate very good agreement with
measured capture coefficients.Comment: 6 pages, 2 figure
Approach to the extremal limit of the Schwarzschild-de Sitter black hole
The quasinormal-mode spectrum of the Schwarzschild-de Sitter black hole is
studied in the limit of near-equal black-hole and cosmological radii. It is
found that the mode_frequencies_ agree with the P"oschl-Teller approximation to
one more order than previously realized, even though the effective_potential_
does not. Whether the spectrum approaches the limiting one uniformly in the
mode index is seen to depend on the chosen units (to the order investigated). A
perturbation framework is set up, in which these issues can be studied to
higher order in future.Comment: REVTeX4, 4pp., no figures. N.B. "Alec" is my first, and "Maassen van
den Brink" my family name. v2: added numerical verificatio
Compilation of extended recursion in call-by-value functional languages
This paper formalizes and proves correct a compilation scheme for
mutually-recursive definitions in call-by-value functional languages. This
scheme supports a wider range of recursive definitions than previous methods.
We formalize our technique as a translation scheme to a lambda-calculus
featuring in-place update of memory blocks, and prove the translation to be
correct.Comment: 62 pages, uses pi
On Quasinormal Modes, Black Hole Entropy, and Quantum Geometry
Loop quantum gravity can account for the Bekenstein-Hawking entropy of a
black hole provided a free parameter is chosen appropriately. Recently, it was
proposed that a new choice of the Immirzi parameter could predict both black
hole entropy and the frequencies of quasinormal modes in the large limit,
but at the price of changing the gauge group of the theory. In this note we use
a simple physical argument within loop quantum gravity to arrive at the same
value of the parameter. The argument uses strongly the necessity of having
fermions satisfying basic symmetry and conservation principles, and therefore
supports SU(2) as the relevant gauge group of the theory.Comment: 3 pages, revtex4, no figures, discussion expanded and references
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