Optimization experiments in the continuous space: The limited growth optimistic optimization algorithm

Online controlled experiments are extensively used by web-facing companies to validate and optimize their systems, providing a competitive advantage in their business. As the number of experiments scale, companies aim to invest their experimentation resources in larger feature changes and leave the automated techniques to optimize smaller features. Optimization experiments in the continuous space are encompassed in the many-armed bandits class of problems. Although previous research provides algorithms for solving this class of problems, these algorithms were not implemented in real-world online experimentation problems and do not consider the application constraints, such as time to compute a solution, selection of a best arm and the estimation of the mean-reward function. This work discusses the online experiments in context of the many-armed bandits class of problems and provides three main contributions: (1) an algorithm modification to include online experiments constraints, (2) implementation of this algorithm in an industrial setting in collaboration with Sony Mobile, and (3) statistical evidence that supports the modification of the algorithm for online experiments scenarios. These contributions support the relevance of the LG-HOO algorithm in the context of optimization experiments and show how the algorithm can be used to support continuous optimization of online systems in stochastic scenarios

A influência do vídeo de informação adicional em pacientes submetidas à mastectomia: o estudo da dor

OBJECTIVE: Pain is a high incidence symptom in cancer patients. In cases of breast cancer, the post mastectomy and post axillary curettage pain syndromes present the characteristic of neural pain and can occur in 10% of patients shortly after surgery. This paper presents the preliminary results of an ongoing research aimed at investigating the possible effects of a modern procedure of information, which used in the evaluation of perception of pain in mastectomy patients at the Mastectomy Center of the Hospital de Clínicas de Porto Alegre, southern Brazil. MATERIALS AND METHODS: A sample of 22 patients was studied according to the classical experimental design with two groups. An informational video was shown to the  experimental group in the pre-surgery period. Both groups were evaluated using the McGill Pain Questionnaire and the Visual Analogue Scale pain score. RESULTS: Results indicated a tendency to reports of more post-surgical pain in the control group in both tests. In some of the subscales of the McGill Questionnaire there were significantly higher scores of post-surgical pain in the control group. CONCLUSIONS: Our findings seem to indicate the benefits of using informational videos with the objective of improving the well-being of patients. However, further studies should be carried out with larger population samples in order to better evaluate the trends observed in this studyOBJETIVO: A dor é um sintoma de alta ocorrência nos casos de câncer. No câncer de mama, as síndromes dolorosas pós-mastectomia e pós-esvaziamento axilar têm a característica de uma dor neural e chegam a ocorrer em 10% das pacientes, podendo aparecer imediatamente após a cirurgia. Este trabalho traz os primeiros resultados de uma pesquisa em andamento, elaborada para investigar os possíveis efeitos de um procedimento moderno de informação na avaliação da percepção de dor de pacientes submetidas à mastectomia no Serviço de Mastologia do Hospital de Clínicas de Porto Alegre.MATERIAIS E MÉTODOS: Uma amostra de 22 pacientes foi estudada segundo o delineamento experimental clássico, com dois grupos. O vídeo de informação foi apresentado no período pré-operatório apenas ao grupo experimental. Ambos os grupos foram avaliados em termos de dor, através do Questionário de McGill e da Escala Análogo-Visual de Dor.RESULTADOS: Os resultados revelaram tendências de maior avaliação da dor pósoperatória no grupo controle em comparação ao grupo experimental, em ambos os testes. Em algumas subescalas do Questionário de McGill houve aumento significativo dos escores de dor após a cirurgia no grupo controle.CONCLUSÕES: Esses achados parecem indicar a utilidade do vídeo de informação com vistas ao bem-estar das pacientes. Sugere-se, entretanto, o aumento da amostra da pesquisa para a melhor avaliação das tendências encontradas

Excited States of Proton-bound DNA/RNA Base Homo-dimers: Pyrimidines

We are presenting the electronic photo fragment spectra of the protonated pyrimidine DNA bases homo-dimers. Only the thymine dimer exhibits a well structured vibrational progression, while protonated monomer shows broad vibrational bands. This shows that proton bonding can block some non radiative processes present in the monomer.Comment: We acknowledge the use of the computing facility cluster GMPCS of the LUMAT federation (FR LUMAT 2764

Effects of gestational age at birth on cognitive performance : a function of cognitive workload demands

Objective: Cognitive deficits have been inconsistently described for late or moderately preterm children but are consistently found in very preterm children. This study investigates the association between cognitive workload demands of tasks and cognitive performance in relation to gestational age at birth. Methods: Data were collected as part of a prospective geographically defined whole-population study of neonatal at-risk children in Southern Bavaria. At 8;5 years, n = 1326 children (gestation range: 23–41 weeks) were assessed with the K-ABC and a Mathematics Test. Results: Cognitive scores of preterm children decreased as cognitive workload demands of tasks increased. The relationship between gestation and task workload was curvilinear and more pronounced the higher the cognitive workload: GA2 (quadratic term) on low cognitive workload: R2 = .02, p<0.001; moderate cognitive workload: R2 = .09, p<0.001; and high cognitive workload tasks: R2 = .14, p<0.001. Specifically, disproportionally lower scores were found for very (<32 weeks gestation) and moderately (32–33 weeks gestation) preterm children the higher the cognitive workload of the tasks. Early biological factors such as gestation and neonatal complications explained more of the variance in high (12.5%) compared with moderate (8.1%) and low cognitive workload tasks (1.7%). Conclusions: The cognitive workload model may help to explain variations of findings on the relationship of gestational age with cognitive performance in the literature. The findings have implications for routine cognitive follow-up, educational intervention, and basic research into neuro-plasticity and brain reorganization after preterm birth

Endothelial PlexinD1 signaling instructs spinal cord vascularization and motor neuron development

How the vascular and neural compartment cooperate to achieve such a complex and highly specialized structure as the central nervous system is still unclear. Here, we reveal a crosstalk between motor neurons (MNs) and endothelial cells (ECs), necessary for the coordinated development of MNs. By analyzing cell-to-cell interaction profiles of the mouse developing spinal cord, we uncovered semaphorin 3C (Sema3C) and PlexinD1 as a communication axis between MNs and ECs. Using cell-specific knockout mice and in vitro assays, we demonstrate that removal of Sema3C in MNs, or its receptor PlexinD1 in ECs, results in premature and aberrant vascularization of MN columns. Those vascular defects impair MN axon exit from the spinal cord. Impaired PlexinD1 signaling in ECs also causes MN maturation defects at later stages. This study highlights the importance of a timely and spatially controlled communication between MNs and ECs for proper spinal cord development