Two-Stage ML-Guided Decision Rules for Sequential Decision Making under Uncertainty

Sequential Decision Making under Uncertainty (SDMU) is ubiquitous in many domains such as energy, finance, and supply chains. Some SDMU applications are naturally modeled as Multistage Stochastic Optimization Problems (MSPs), but the resulting optimizations are notoriously challenging from a computational standpoint. Under assumptions of convexity and stage-wise independence of the uncertainty, the resulting optimization can be solved efficiently using Stochastic Dual Dynamic Programming (SDDP). Two-stage Linear Decision Rules (TS-LDRs) have been proposed to solve MSPs without the stage-wise independence assumption. TS-LDRs are computationally tractable, but using a policy that is a linear function of past observations is typically not suitable for non-convex environments arising, for example, in energy systems. This paper introduces a novel approach, Two-Stage General Decision Rules (TS-GDR), to generalize the policy space beyond linear functions, making them suitable for non-convex environments. TS-GDR is a self-supervised learning algorithm that trains the nonlinear decision rules using stochastic gradient descent (SGD); its forward passes solve the policy implementation optimization problems, and the backward passes leverage duality theory to obtain closed-form gradients. The effectiveness of TS-GDR is demonstrated through an instantiation using Deep Recurrent Neural Networks named Two-Stage Deep Decision Rules (TS-DDR). The method inherits the flexibility and computational performance of Deep Learning methodologies to solve SDMU problems generally tackled through large-scale optimization techniques. Applied to the Long-Term Hydrothermal Dispatch (LTHD) problem using actual power system data from Bolivia, the TS-DDR not only enhances solution quality but also significantly reduces computation times by several orders of magnitude.Comment: 10 Main Pages, 6 Appendices, 6 Figure

Lymphocyte subsets in human immunodeficiency virus-unexposed Brazilian individuals from birth to adulthood

Ethnic origin, genetics, gender and environmental factors have been shown to influence some immunologic indices, so that development of reference values for populations of different backgrounds may be necessary. We have determined the distribution of lymphocyte subsets in healthy Brazilian individuals from birth to adulthood. Lymphocyte subsets were determined using four-colour cytometry in a cross-sectional study of 463 human immunodeficiency virus-unexposed children and adults from birth through 49 years of age. Lymphocyte subsets varied according to age, as previously observed in other studies. However, total CD4+ T cell numbers were lower than what was described in the Pediatric AIDS Clinical Trials Group P1009 (PACTG P1009), which assessed an American population of predominantly African and Hispanic backgrounds until the 12-18 year age range, when values were comparable. Naïve percentages and absolute values of CD8+ T cells, as assessed by CD45RA expression, were also lower than the PACTG P1009 data for all analysed age ranges. CD38 expression on both CD4+ and CD8+ T cells was lower than the PACTG P1009 values, with a widening gap between the two studies at older age ranges. Different patterns of cell differentiation seem to occur in different settings and may have characteristic expression within each population.Universidade Federal de São Paulo (UNIFESP) Departamento de MedicinaCentro Assistencial Cruz de MaltaUniversidade Federal de São Paulo (UNIFESP) Departamento de PediatriaUNIFESP, Depto. de MedicinaUNIFESP, Depto. de PediatriaSciEL

Nuevo ensayo para la determinación de frecuencias fundamentales longitudinales, transversales y torsionales en probetas de hormigón

For twenty-five years The ASTM method used to determine reductions in concrete durability after freeze-thaw cycling has been C215-60. In this test the fundamental frequencies of a concrete specimen are compared. This test is time consuming, noisy and often inaccurate. In this paper a new method is proposed for measuring the fundamental frequencies of concrete to a single tap via a Fast Fourier Transform. The new test is faster, simpler and more accurate.El método usado por la ASTM desde hace 25 años para la determinación de la durabilidad del hormigón después de sufrir ciclos hielo/deshielo ha sido el C215-60. En este ensayo se comparan las frecuencias fundamentales de una probeta de hormigón. Este ensayo es ruidoso, lleva bastante tiempo y es bastante impreciso. En este trabajo se pone un nuevo método para medias frecuencias fundamentales en el hormigón por simple golpe mediante la TRANSFORMADA RÁPIDA de FOURIER. El nuevo método es más rápido, más simple y más preciso

CTNNB1, AXIN1 and APC expression analysis of different medulloblastoma variants

OBJECTIVES: We investigated four components of the Wnt signaling pathway in medulloblastomas. Medulloblastoma is the most common type of malignant pediatric brain tumor, and the Wnt signaling pathway has been shown to be activated in this type of tumor. METHODS: Sixty-one medulloblastoma cases were analyzed for β-catenin gene (CTNNB1) mutations, β-catenin protein expression via immunostaining and Wnt signaling pathway-related gene expression. All data were correlated with histological subtypes and patient clinical information. RESULTS: CTNNB1 sequencing analysis revealed that 11 out of 61 medulloblastomas harbored missense mutations in residues 32, 33, 34 and 37, which are located in exon 3. These mutations alter the glycogen synthase kinase-3β phosphorylation sites, which participate in β-catenin degradation. No significant differences were observed between mutation status and histological medulloblastoma type, patient age and overall or progression-free survival times. Nuclear β-catenin accumulation, which was observed in 27.9% of the cases, was not associated with the histological type, CTNNB1 mutation status or tumor cell dissemination. The relative expression levels of genes that code for proteins involved in the Wnt signaling pathway (CTNNB1, APC, AXIN1 and WNT1) were also analyzed, but no significant correlations were found. In addition, large-cell variant medulloblastomas presented lower relative CTNNB1 expression as compared to the other tumor variants. CONCLUSIONS: A small subset of medulloblastomas carry CTNNB1 mutations with consequent nuclear accumulation of β-catenin. The Wnt signaling pathway plays a role in classic, desmoplastic and extensive nodularity medulloblastoma variants but not in large-cell medulloblastomas

Aspectos sistemáticos, paleobiogeográficos e paleoclimáticos dos mamíferos quaternários de Fazenda Nova, PE, nordeste do Brasil

The fossil mammals from the Fazenda Nova locality, Northeastern Brazil, represent an interval older than the Pleistocene-Holocene transition and include Xenarthra, Glyptodontidae, Glyptatelinae (with Pachyarmatherium sp.), Glyptodontinae, Glyptotheriini, Hoplophorinae indet., Pampatheriidae (with Holmesina cf. H. paulacoutoi), Megalonychidae, gen. et sp. indet., Megatheriidae (represented by Eremotherium laurillardi), Notoungulata, Toxodontinae (with Toxodon sp.), and Proboscidea (represented by Stegomastodon waringi). This paper reports and discusses the fi rst record of the North American glyptodont Glyptotheriini in Brazil, the first occurrence of Pachyarmatherium in Quaternary rocks of Pernambuco State, and the taxonomic history of the problematical taxon Chlamydotherium. OSL dating of the sediments and ESR dating of Stegomastodon teeth placed the Fazenda Nova deposits between 58.900 e 63.800 yr BP, which is equivalent to the IOS 3 and the Middle Wisconsin interstadial event recorded in the northern Andean South America. The mammal fauna from Fazenda Nova shows affinities with other southeastern and northeastern Brazilian faunas and, by the presence of Glyptotheriini and Pachyarmatherium, with those from northern South America, Central America and southern North American faunas, suggesting a warm and wet climate to the region at late Pleistocene. Key words: mammals, late Pleistocene, taxonomy, paleoclimate, ESR and OSL ages, Brazil.Os mamíferos fósseis de Fazenda Nova, na região Nordeste do Brasil, são representativos de um intervalo mais antigo que a transição Pleistoceno- Holoceno. Incluem Xenarthra, Glyptodontidae, Glyptatelinae (representado por Pachyarmatherium sp.), Glyptodontinae, Glyptotheriini, Hoplophorinae gen. et sp. indet., Pampatheriidae (representado por Holmesina cf. H. paulacoutoi), Megalonychidae gen. et sp. indet., Megatheriidae (Eremotherium laurillardi), Notoungulata, Toxodontinae (representado por Toxodon sp.) e Proboscidea (cuja forma conhecida é Stegomastodon waringi). Registra-se e discute-se neste artigo a ocorrência inédita de representantes da tribo norteamericana Glyptotheriini no Brasil, bem como do gênero Pachyarmatherium no Estado de Pernambuco, e se apresenta o histórico do tratamento taxonômico do táxon Chlamydotherium. Datações por Luminescência Opticamente Estimulada (LOE) nos sedimentos e por Ressonância Paramagnética Eletronica (EPR) nos dentes associados de Stegomastodon posicionam a fauna de Fazenda Nova entre 58.900 e 63.800 anos AP, equivalente ao estágio isotópico IOS 3 e ao evento interstadial wisconsiniano médio, registrado na região andina norte da América do Sul. O conjunto da fauna mostra afinidades com outras do sudeste e nordeste do Brasil e a presença de Glyptotheriini e Pachyarmatherium, com aquelas do norte da América do Sul, da América Central e do sul da América do Norte, e sugere condições de clima quente e úmido para a época da deposição. Palavras-chave: mamíferos, Pleistoceno Superior, taxonomia, paleoclima, datações EPR e LOE, Brasil