The Index-Based Subgraph Matching Algorithm with General Symmetries (ISMAGS):Exploiting Symmetry for Faster Subgraph Enumeration

Subgraph matching algorithms are used to find and enumerate specific interconnection structures in networks. By enumerating these specific structures/subgraphs, the fundamental properties of the network can be derived. More specifically in biological networks, subgraph matching algorithms are used to discover network motifs, specific patterns occurring more often than expected by chance. Finding these network motifs yields information on the underlying biological relations modelled by the network. In this work, we present the Index-based Subgraph Matching Algorithm with General Symmetries (ISMAGS), an improved version of the Index-based Subgraph Matching Algorithm (ISMA). ISMA quickly finds all instances of a predefined motif in a network by intelligently exploring the search space and taking into account easily identifiable symmetric structures. However, more complex symmetries (possibly involving switching multiple nodes) are not taken into account, resulting in superfluous output. ISMAGS overcomes this problem by using a customised symmetry analysis phase to detect all symmetric structures in the network motif subgraphs. These structures are then converted to symmetry-breaking constraints used to prune the search space and speed up calculations. The performance of the algorithm was tested on several types of networks (biological, social and computer networks) for various subgraphs with a varying degree of symmetry. For subgraphs with complex (multi-node) symmetric structures, high speed-up factors are obtained as the search space is pruned by the symmetry-breaking constraints. For subgraphs with no or simple symmetric structures, ISMAGS still reduces computation times by optimising set operations. Moreover, the calculated list of subgraph instances is minimal as it contains no instances that differ by only a subgraph symmetry. An implementation of the algorithm is freely available at https://github.com/mhoubraken/ISMAGS

Catch-Up Growth Following Fetal Growth Restriction Promotes Rapid Restoration of Fat Mass but Without Metabolic Consequences at One Year of Age

BACKGROUND: Fetal growth restriction (FGR) followed by rapid weight gain during early life has been suggested to be the initial sequence promoting central adiposity and insulin resistance. However, the link between fetal and early postnatal growth and the associated anthropometric and metabolic changes have been poorly studied. METHODOLOGY/PRINCIPAL FINDINGS: Over the first year of post-natal life, changes in body mass index, skinfold thickness and hormonal concentrations were prospectively monitored in 94 infants in whom the fetal growth velocity had previously been measured using a repeated standardized procedure of ultrasound fetal measurements. 45 infants, thinner at birth, had experienced previous FGR (FGR+) regardless of birth weight. Growth pattern in the first four months of life was characterized by greater change in BMI z-score in FGR+ (+1.26+/-1.2 vs +0.58 +/-1.17 SD in FGR-) resulting in the restoration of BMI and of fat mass to values similar to FGR-, independently of caloric intakes. Growth velocity after 4 months was similar and BMI z-score and fat mass remained similar at 12 months of age. At both time-points, fetal growth velocity was an independent predictor of fat mass in FGR+. At one year, fasting insulin levels were not different but leptin was significantly higher in the FGR+ (4.43+/-1.41 vs 2.63+/-1 ng/ml in FGR-). CONCLUSION: Early catch-up growth is related to the fetal growth pattern itself, irrespective of birth weight, and is associated with higher insulin sensitivity and lower leptin levels after birth. Catch-up growth promotes the restoration of body size and fat stores without detrimental consequences at one year of age on body composition or metabolic profile. The higher leptin concentration at one year may reflect a positive energy balance in children who previously faced fetal growth restriction

Anthropogenic intensification of short-duration rainfall extremes

Short- duration (1-3 h) rainfall extremes can cause serious damage to societies through rapidly developing (flash) flooding and are determined by complex, multifaceted processes that are altering as Earth's climate warms. In this Review, we examine evidence from observational, theoretical and modelling studies for the intensification of these rainfall extremes, the drivers and the impact on flash flooding. Both short- duration and long- duration (\textgreater1 day) rainfall extremes are intensifying with warming at a rate consistent with the increase in atmospheric moisture (~7% K-1), while in some regions, increases in short- duration extreme rainfall intensities are stronger than expected from moisture increases alone. These stronger local increases are related to feedbacks in convective clouds, but their exact role is uncertain because of the very small scales involved. Future extreme rainfall intensification is also modulated by changes to temperature stratification and large- scale atmospheric circulation. The latter remains a major source of uncertainty. Intensification of short- duration extremes has likely increased the incidence of flash flooding at local scales and this can further compound with an increase in storm spatial footprint to considerably increase total event rainfall. These findings call for urgent climate change adaptation measures to manage increasing flood risks

A mortalidade materna nas capitais brasileiras: algumas características e estimativa de um fator de ajuste Maternal mortality in Brazilian State Capitals: some characteristics and estimates for an adjustment factor

A mortalidade materna pode ser considerada um excelente indicador de saúde, não só da mulher, mas da população geral; mostra, também, iniqüidades. A redução da mortalidade materna é uma das principais metas, estando também incluída nas Metas do Desenvolvimento do Milênio da ONU. OBJETIVO: Conhecer a qualidade da informação da mortalidade de mulheres de 10 a 49 anos, e estimar a razão de mortalidade materna (RMM) e os fatores de ajuste para os dados oficiais, no conjunto das capitais de estados brasileiros e Distrito Federal. METODOLOGIA: Adotou-se a metodologia RAMOS (a partir da declaração de óbito, entrevista no domicílio da mulher falecida, com preenchimento de questionário, sobre variáveis demográficas, epidemiológicas, clínicas e de acesso a serviços; seguiam-se consultas a prontuários médicos hospitalares e a laudos de autópsia). Após o resgate da informação, pôde ser feita análise das reais causas básicas, terminais e associadas. A população de estudo foi estimada em 7.332 mortes de mulheres de 10 a 49 anos, ocorridas no primeiro semestre de 2002, sendo 239 óbitos por causas maternas. A RMM foi de 54,3 por cem mil nascidos vivos (n.v.), no conjunto de capitais, variando entre 42 por cem mil n.v. no Sul, e 73,2 por cem mil n.v. no Nordeste. O fator de ajuste para o conjunto das capitais brasileiras foi igual a 1,4; para as regiões (considerando apenas as capitais), variaram entre 1,08 na Região Norte e 1,83 na Região Sul. As mortes obstétricas diretas corresponderam a 67,1%, mostrando que assistência ao pré-natal, ao parto e ao puerpério deve ser aprimorada.<br>INTRODUCTION: There is criticism as to the heterogeneity and reliability of mortality data in Brazilian Regions. However, official mortality statistics of State Capitals are more accurate and have adequate coverage. Reduction of maternal mortality is one of the world's major goals and it is measured by the Maternal Mortality Ratio. International agencies have been estimating that the Brazilian ratio is very high. An investigation was carried out to know the actual value. OBJECTIVE: The aim was to calculate the maternal mortality ratio for Brazilian Capitals and the Federal District and estimate an adjustment factor for official data. METHODOLOGY: A total of 7,332 deaths that occurred in the first semester of 2002 in women from 10 to 49 years of age living in these areas were investigated, using the RAMOS methodology (household interviews and investigation of medical and hospital records and autopsies.). RESULTS: The maternal mortality ratio calculated was 54.3 per 100,000 live born, ranging between 73.2 in the North State Capitals and 42 per 100,000 live born in the South. The lowest adjustment factors were 1.08 in the North Region, and 1.10 in the Middle West State Capitals. The highest values were 1.76 and 1.83 in the Northeast and South Regions. Considering the set of Brazilian State Capitals, the adjustment factor estimated was equal to 1.4. The maternal mortality ratios observed were lower than WHO, UNICEF and UNFPA values. Direct obstetric maternal deaths accounted for 67.1% of the total, thus indicating that pre-natal and childbirth care must be improved