Optimized parameter search for large datasets of the regularization parameter and feature selection for ridge regression

In this paper we propose mathematical optimizations to select the optimal regularization parameter for ridge regression using cross-validation. The resulting algorithm is suited for large datasets and the computational cost does not depend on the size of the training set. We extend this algorithm to forward or backward feature selection in which the optimal regularization parameter is selected for each possible feature set. These feature selection algorithms yield solutions with a sparse weight matrix using a quadratic cost on the norm of the weights. A naive approach to optimizing the ridge regression parameter has a computational complexity of the order with the number of applied regularization parameters, the number of folds in the validation set, the number of input features and the number of data samples in the training set. Our implementation has a computational complexity of the order . This computational cost is smaller than that of regression without regularization for large datasets and is independent of the number of applied regularization parameters and the size of the training set. Combined with a feature selection algorithm the algorithm is of complexity and for forward and backward feature selection respectively, with the number of selected features and the number of removed features. This is an order faster than and for the naive implementation, with for large datasets. To show the performance and reduction in computational cost, we apply this technique to train recurrent neural networks using the reservoir computing approach, windowed ridge regression, least-squares support vector machines (LS-SVMs) in primal space using the fixed-size LS-SVM approximation and extreme learning machines

Established maternal obesity in the rat reprograms hypothalamic appetite regulators and leptin signaling at birth

Objective: Key appetite regulators and their receptors are already present in the fetal hypothalamus, and may respond to hormones such as leptin. Intrauterine food restriction or hyperglycemia can reprogram these circuits, possibly predisposing individuals to adverse health outcomes in adulthood. Given the global obesity epidemic, maternal overweight and obesity is becoming more prevalent. Earlier, we observed rapid growth of pups from obese dams during the suckling period. However, it is unclear whether this is because of alterations in leptin and hypothalamic appetite regulators at birth. Design: Female Sprague-Dawley rats were fed palatable high-fat diet (HFD) or chow for 5 weeks to induce obesity before mating. The same diet continued during gestation. At day 1, after birth, plasma and hypothalamus were collected from male and female pups. Measurements: Body weight and organ mass were recorded. Leptin and insulin levels were measured in the plasma by radioimmunoassay. Hypothalamic mRNA expression of neuropeptide-Y (NPY), pro-opiomelanocortin, leptin receptor and its downstream signal, STAT3 (signal transducer and activator of transcription 3), were measured using real-time PCR. Results: Body and organ weights of pups from obese dams were similar to those from lean dams, across both genders. However, plasma leptin levels were significantly lower in offspring from obese dams (male: 0.53±0.13 vs 1.05±0.21 ng ml-1; female: 0.33±0.09 vs 2.12±0.57 ng ml-1, respectively; both P<0.05). Hypothalamic mRNA expression of NPY, pro-opiomelanocortin, leptin receptor and STAT3 were also significantly lower in pups from obese dams. Conclusion: Long-term maternal obesity, together with lower leptin levels in pups from obese dams may contribute to the lower expression of key appetite regulators on day 1 of life, suggesting altered intrauterine neuron development in response to intrauterine overnutrition, which may contribute to eating disorders later in life. © 2009 Macmillan Publishers Limited All rights reserved

Superando las probabilidades: la democracia deliberativa confrontacional

Even the most skeptical views might concede that deliberative practices, if ever realized, have the potential to provide contemporary democracies, including those in divided societies, with a much needed, reinvig-orating boost. But achievement of a minimal consensus on conditions for that realization, and their feasibility, nevertheless lies way ahead. In the search for elements of discussion that might help us advance in this debate, the cross-sectional assessment given here, based on the various cases presented throughout the book, suggests how aspects of confrontation and deliberation could be regularly combined in practice, and what general conditions could facilitate such an uneasy accommodation

Reimagining Engagement between Citizens and Parliament

This chapter reimagines the relationship between citizens and parliament. Five core principles of public engagement – inclusivity, relevance, relatability, continuity and sustainability – drive the process of reimagining; and result in a reimagined parliamentary public engagement that would be welcoming and inclusive, consequential and future generations aware. In reflecting upon how far the UK parliament is from this reimagined future, core features of parliament – such as its collective and hierarchical nature, and its dependency on electoral cycles – are identified as inhibitors of a principled reimagining of parliamentary public engagement. The chapter concludes by calling for a far more institutionalised approach to engagement, to make it more meaningful, consequential and better resourced

Does the presence of conflict affect maternal and neonatal mortality during Caesarean sections?

Introduction: Conflicts frequently occur in countries with high maternal and neonatal mortality and can aggravate difficulties accessing emergency care. No literature is available on whether the presence of conflict influences the outcomes of mothers and neonates during Caesarean sections (C-sections) in high-mortality settings.Objective: To determine whether the presence of conflict was associated with changes in maternal and neonatal mortality during C-sections.Methods: We analysed routinely collected data on C-sections from 17 Médecins Sans Frontières (MSF) health facilities in 12 countries. Exposure variables included presence and intensity of conflict, type of health facility and other types of access to emergency care.Results: During 2008–2015, 30,921 C-sections were performed in MSF facilities; of which 55.4% were in areas of conflict. No differences were observed in maternal mortality in conflict settings (0.1%) vs. non-conflict settings (0.1%) (P = 0.08), nor in neonatal mortality between conflict (12.2%) and non-conflict settings (11.5%) (P = 0.1). Among the C-sections carried out in conflict settings, neonatal mortality was slightly higher in war zones compared to areas of minor conflict (P = 0.02); there was no difference in maternal mortality (P = 0.38).Conclusions: Maternal and neonatal mortality did not appear to be affected by the presence of conflict in a large number of MSF facilities. This finding should encourage humanitarian organisations to support C-sections in conflict settings to ensure access to quality maternity care.</jats:p