Dynamical system analysis and forecasting of deformation produced by an earthquake fault

We present a method of constructing low-dimensional nonlinear models describing the main dynamical features of a discrete 2D cellular fault zone, with many degrees of freedom, embedded in a 3D elastic solid. A given fault system is characterized by a set of parameters that describe the dynamics, rheology, property disorder, and fault geometry. Depending on the location in the system parameter space we show that the coarse dynamics of the fault can be confined to an attractor whose dimension is significantly smaller than the space in which the dynamics takes place. Our strategy of system reduction is to search for a few coherent structures that dominate the dynamics and to capture the interaction between these coherent structures. The identification of the basic interacting structures is obtained by applying the Proper Orthogonal Decomposition (POD) to the surface deformations fields that accompany strike-slip faulting accumulated over equal time intervals. We use a feed-forward artificial neural network (ANN) architecture for the identification of the system dynamics projected onto the subspace (model space) spanned by the most energetic coherent structures. The ANN is trained using a standard back-propagation algorithm to predict (map) the values of the observed model state at a future time given the observed model state at the present time. This ANN provides an approximate, large scale, dynamical model for the fault.Comment: 30 pages, 12 figure

Particulate matter exposure during pregnancy is associated with birth weight, but not gestational age, 1962-1992: a cohort study

<p>Abstract</p> <p>Background</p> <p>Exposure to air pollutants is suggested to adversely affect fetal growth, but the evidence remains inconsistent in relation to specific outcomes and exposure windows.</p> <p>Methods</p> <p>Using birth records from the two major maternity hospitals in Newcastle upon Tyne in northern England between 1961 and 1992, we constructed a database of all births to mothers resident within the city. Weekly black smoke exposure levels from routine data recorded at 20 air pollution monitoring stations were obtained and individual exposures were estimated via a two-stage modeling strategy, incorporating temporally and spatially varying covariates. Regression analyses, including 88,679 births, assessed potential associations between exposure to black smoke and birth weight, gestational age and birth weight standardized for gestational age and sex.</p> <p>Results</p> <p>Significant associations were seen between black smoke and both standardized and unstandardized birth weight, but not for gestational age when adjusted for potential confounders. Not all associations were linear. For an increase in whole pregnancy black smoke exposure, from the 1^st(7.4 μg/m³) to the 25^th(17.2 μg/m³), 50^th(33.8 μg/m³), 75^th(108.3 μg/m³), and 90^th(180.8 μg/m³) percentiles, the adjusted estimated decreases in birth weight were 33 g (SE 1.05), 62 g (1.63), 98 g (2.26) and 109 g (2.44) respectively. A significant interaction was observed between socio-economic deprivation and black smoke on both standardized and unstandardized birth weight with increasing effects of black smoke in reducing birth weight seen with increasing socio-economic disadvantage.</p> <p>Conclusions</p> <p>The findings of this study progress the hypothesis that the association between black smoke and birth weight may be mediated through intrauterine growth restriction. The associations between black smoke and birth weight were of the same order of magnitude as those reported for passive smoking. These findings add to the growing evidence of the harmful effects of air pollution on birth outcomes.</p

Development and validation of a risk prediction model for 1-year readmission among young adults hospitalized for acute myocardial infarction

BACKGROUND: Readmission over the first year following hospitalization for acute myocardial infarction (AMI) is common among younger adults (≤55 years). Our aim was to develop/validate a risk prediction model that considered a broad range of factors for readmission within 1 year. METHODS AND RESULTS: We used data from the VIRGO (Variation in Recovery: Role of Gender on Outcomes of Young AMI Patients) study, which enrolled young adults aged 18 to 55 years hospitalized with AMI across 103 US hospitals (N=2979). The primary outcome was ≥1 all-cause readmissions within 1 year of hospital discharge. Bayesian model averaging was used to select the risk model. The mean age of participants was 47.1 years, 67.4% were women, and 23.2% were Black. Within 1 year of discharge for AMI, 905 (30.4%) of participants were readmitted and were more likely to be female, Black, and nonmarried. The final risk model consisted of 10 predictors: depressive symptoms (odds ratio [OR], 1.03; 95% CI, 1.01–1.05), better physical health (OR, 0.98; 95% CI, 0.97–0.99), in-hospital complication of heart failure (OR, 1.44; 95% CI, 0.99–2.08), chronic obstructive pulmomary disease (OR, 1.29; 95% CI, 0.96–1.74), diabetes mellitus (OR, 1.23; 95% CI, 1.00–1.52), female sex (OR, 1.31; 95% CI, 1.05–1.65), low income (OR, 1.13; 95% CI, 0.89–1.42), prior AMI (OR, 1.47; 95% CI, 1.15–1.87), in-hospital length of stay (OR, 1.13; 95% CI, 1.04–1.23), and being employed (OR, 0.88; 95% CI, 0.69–1.12). The model had excellent calibration and modest discrimination (C statistic=0.67 in development/validation cohorts). CONCLUSIONS: Women and those with a prior AMI, increased depressive symptoms, longer inpatient length of stay and diabetes may be more likely to be readmitted. Notably, several predictors of readmission were psychosocial characteristics rather than markers of AMI severity. This finding may inform the development of interventions to reduce readmissions in young patients with AMI

Sex Differences in Timeliness of Reperfusion in Young Patients With ST-Segment-Elevation Myocardial Infarction by Initial Electrocardiographic Characteristics

Background-Young women with ST-segment-elevation myocardial infarction experience reperfusion delays more frequently than men. Our aim was to determine the electrocardiographic correlates of delay in reperfusion in young patients with ST-segment-elevation myocardial infarction. Methods and Results-We examined sex differences in initial electrocardiographic characteristics among 1359 patients with ST-segment-elevation myocardial infarction in a prospective, observational, cohort study (2008-2012) of 3501 patients with acute myocardial infarction, 18 to 55 years of age, as part of the VIRGO (Variation in Recovery: Role of Gender on Outcomes of Young AMI Patients) study at 103 US and 24 Spanish hospitals enrolling in a 2:1 ratio for women/men. We created a multivariable logistic regression model to assess the relationship between reperfusion delay (door-to-balloon time >90 or >120 minutes for transfer or door-to-needle time >30 minutes) and electrocardiographic characteristics, adjusting for sex, sociodemographic characteristics, and clinical characteristics at presentation. In our study (834 women and 525 men), women were more likely to exceed reperfusion time guidelines than men (42.4\% versus 31.5\%; P<0.01). In multivariable analyses, female sex persisted as an important factor in exceeding reperfusion guidelines after adjusting for electrocardiographic characteristics (odds ratio, 1.57; 95\% CI, 1.15-2.15). Positive voltage criteria for left ventricular hypertrophy and absence of a prehospital ECG were positive predictors of reperfusion delay; and ST elevation in lateral leads was an inverse predictor of reperfusion delay. Conclusions-Sex disparities in timeliness to reperfusion in young patients with ST-segment-elevation myocardial infarction persisted, despite adjusting for initial electrocardiographic characteristics. Left ventricular hypertrophy by voltage criteria and absence of prehospital ECG are strongly positively correlated and ST elevation in lateral leads is negatively correlated with reperfusion delay.This work was supported by grants from the National Heart, Lung, and Blood Institute, National Institutes of Health, Department of Health and Human Services (R01 HL081153, F30HL120498 to EMB, and U01 HL105270 to the Center for Cardiovascular Outcomes Research at Yale University). Infarto de miocardio en la Mujer Joven (the Spanish component of VIRGO [Variation in Recovery: Role of Gender on Outcomes of Young AMI Patients]) is supported in Spain by the Fondo de Investigaciones Sanitarias del Instituto Carlos III, Ministry of Science and Technology (PI 081614) and additional funds from the Centro Nacional de Investigaciones Cardiovasculares. Gupta is supported by grant HL007854 from the National Institutes of Health. Spatz is supported by grant K12HS023000 from the Agency for Healthcare Research and Quality Patient-Centered Outcomes Research Institute Mentored Career Development Program.S

Gender differences in pre-event health status of young patients with acute myocardial infarction: A VIRGO study analysis

Aims: We assessed gender differences in pre-event health status (symptoms, functioning, quality of life) in young patients with acute myocardial infarction and whether or not this association persists following sequential adjustment for important covariates. We also evaluated the interaction between gender and prior coronary artery disease, given that aggressive symptom control is a cornerstone of care in those with known coronary disease. Methods and results: A total of 3501 acute myocardial infarction patients (2349 women) aged 18–55 years were enrolled from 103 US/24 Spanish hospitals (2008–2012). Clinical/health status information was obtained by medical record abstraction and patient interviews. Pre-event health status was measured by generic (Short Form-12, EuroQoL) and disease-specific (Seattle Angina Questionnaire) measures. T-test/chi-square and multivariable linear/logistic regression analysis was utilized, sequentially adjusting for covariates. Women had more co-morbidities and significantly lower generic mean health scores than men (Short Form-12 physical health = 43±12 vs. 46±11 and mental health = 44±13 vs. 48±11); EuroQoL utility index = 0.7±0.2 vs. 0.8±0.2 and visual analog scale = 63±22 vs. 67±20, P < 0.0001 for all. Their disease-specific health status was also worse, with more angina (Seattle Angina Questionnaire angina frequency = 83±22 vs. 87±18), worse physical function (physical limitation = 78±27 vs. 87±21) and poorer quality of life (55±25 vs. 60±22, P<0.0001 for all). In multivariable analysis, the association between female gender and worse generic physical/mental health persisted, as well as worse disease-specific physical limitation and quality of life. The interaction between gender and prior coronary artery disease was not significant in any of the health status outcomes. Conclusion: Young women have worse pre-event health status as compared with men, regardless of their coronary artery disease history. While future studies of gender differences should adjust for baseline health status, an opportunity may exist to better address the pre-event health status of women at risk for acute myocardial infarction.Keywords: Health status, women, acute myocardial infarction, quality of lif

Evaluación de nuevas variables que apuntan a la mejora del bienestar animal y al logro de ovinos más resilientes a condiciones extensivas en la raza Merino Australiano.

El objetivo de este trabajo (financiado por Smarter H2020 y Rumiar) fue caracterizar algunas de estas nuevas variables, así como establecer relaciones entre ellas y/o con otras variables conocidas, para 3 años de evaluación en la raza Merino Australiano. Estas variables y su interacción con la productividad y eficiencia animal serán utilizadas para la evaluación y caracterización de la resiliencia y robustez de las majadas