The Peculiar Phase Structure of Random Graph Bisection

The mincut graph bisection problem involves partitioning the n vertices of a graph into disjoint subsets, each containing exactly n/2 vertices, while minimizing the number of "cut" edges with an endpoint in each subset. When considered over sparse random graphs, the phase structure of the graph bisection problem displays certain familiar properties, but also some surprises. It is known that when the mean degree is below the critical value of 2 log 2, the cutsize is zero with high probability. We study how the minimum cutsize increases with mean degree above this critical threshold, finding a new analytical upper bound that improves considerably upon previous bounds. Combined with recent results on expander graphs, our bound suggests the unusual scenario that random graph bisection is replica symmetric up to and beyond the critical threshold, with a replica symmetry breaking transition possibly taking place above the threshold. An intriguing algorithmic consequence is that although the problem is NP-hard, we can find near-optimal cutsizes (whose ratio to the optimal value approaches 1 asymptotically) in polynomial time for typical instances near the phase transition.Comment: substantially revised section 2, changed figures 3, 4 and 6, made minor stylistic changes and added reference

Attributes and definitions of locomotor capacity in older people: a World Health Organisation (WHO) locomotor capacity working group meeting report

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Effectiveness of community-based peer support for mothers to improve their breastfeeding practices: A systematic review and meta-analysis

<div><p>Breastfeeding is associated with reduced mortality in children aged less than 5 years. We conducted a systematic review and meta-analysis (registered as PROSPERO 2015: CRD42015019105) to examine the effectiveness of community-based peer support for mothers on their breastfeeding practices as compared to mothers who have not received such a support.</p><p>Methods</p><p>We searched for evidence regarding community-based peer support for mothers in databases, such as PubMed/MEDLINE, the Cochrane Library, CINAHL, Web of Science, SocINDEX, and PsycINFO. We selected three outcome variables for breastfeeding practices, namely, exclusive breastfeeding duration, breastfeeding within the first hour of life, and prelacteal feeding. We conducted meta-analyses of the included randomized controlled trials and quasi-experimental studies.</p><p>Results</p><p>For our review, we selected 47 articles for synthesis out of 1,855 retrieved articles. In low- and middle-income countries, compared to usual care, community-based peer support increased exclusive breastfeeding at 3 months (RR: 1.90, 95% CI: 1.62–2.22), at 5 months (RR: 9.55, 95% CI: 6.65–13.70) and at 6 months (RR: 3.53, 95% CI: 2.49–5.00). In high-income countries, compared to usual care, peer support increased exclusive breastfeeding at 3 months (RR: 2.61, 95% CI: 1.15–5.95). In low- and middle-income countries, compared to usual care, peer support increased the initiation of breastfeeding within the first hour of life (RR: 1.51, 95% CI: 1.04–2.21) and decreased the risk of prelacteal feeding (RR: 0.38, 95% CI: 0.33–0.45).</p><p>Conclusions</p><p>Community-based peer support for mothers is effective in increasing the duration of exclusive breastfeeding, particularly for infants aged 3–6 months in low- and middle-income countries. Such support also encourages mothers to initiate breastfeeding early and prevents newborn prelacteal feeding.</p></div

Expertní systémy na platformě PDA

Import 20/04/2006Prezenční výpůjčkaVŠB - Technická univerzita Ostrava. Fakulta elektrotechniky a informatiky. Katedra (456) informatik

Crack growth propagation modeling based on moving mesh method and interaction integral approach

Abstract This study presents a novel modeling strategy for predicting crack propagation phenomena in linear elastic continuum media under external loading conditions. The model combines the Moving Mesh method with Interaction integral approach in a FE framework. The former is used to reproduce the changes in the geometry caused by crack evolution, whereas the latter is adopted to evaluate the stress intensity factors (SIFs) to predict crack growth. The computational nodes are moved starting from a fixed referential coordinate system on the basis of a crack growth criterion, which predicts the direction of crack propagation at tip front. The mesh frame is changed, ensuring limited distortions of the elements by using a mesh regularization technique based on proper rezoning equations. This strategy also reduces re-meshing processes, which frequently occur in standard crack propagation FE procedures. The validity of the proposed model is verified through comparisons with existing experimental data and other advanced numerical approaches

Pooled relative risk and 95% confidence intervals for the effect of community-based peer support for mothers on duration of exclusive breastfeeding in high income countries.

<p>Pooled relative risk and 95% confidence intervals for the effect of community-based peer support for mothers on duration of exclusive breastfeeding in high income countries.</p

Pooled relative risk and confidence intervals for the effect of community-based peer support for mothers on exclusive breastfeeding at six months (subgroup analysis by type of the interventions).

<p>Pooled relative risk and confidence intervals for the effect of community-based peer support for mothers on exclusive breastfeeding at six months (subgroup analysis by type of the interventions).</p

Characteristics of included studies.

<p>Characteristics of included studies.</p