Análise da correlação de longo prazo do preço Spot no mercado elétrico colombiano

Este artículo cuestiona los supuestos de los modelos financieros que se suelen usar para analizar el precio de la energía. Parte de un análisis exploratorio de los rendimientos diarios para rechazar las hipótesis de aditividad, volatilidad, independencia y normalidad. Con el uso de herramientas asociadas al análisis fractal y en potencia se detectan varios comportamientos: una reversión de losrendimientos (exponente de Hurst de 0.39 y dimensión fractal de 1.61), ciclos que son múltiplos de 7 días, inexistencia de varianza poblacional, cambios asimétricos, alta probabilidad de ocurrencia de valores extremos y buen ajuste a la distribución α-estable. Estos comportamientos destacan la necesidad de elaborar métodos que incorporen los elementos necesarios para analizar sistemas dinámicos no lineales.This paper focuses on the role of the multinational corporations in the Colombian peace process. First a theoretical frame work is built which aims to shed light on the significance of multinationals in this process. The study then presents the specific Colombian experience with relation to the role of multinationals in the peace process. The penultimate section deals with the relation between peace, corporate social responsibility, and the UN Global Compact. Finally it offers a conclusion with regards to the role of multinational companies in the Colombian peace process.Este artigo questiona as suposições dos modelos financeiros que se costumam usar para analisar o preço da energia. Parte de uma análise exploratória dos rendimentos diários para recusar as hipóteses de aditividade, volatilidade, independencia e normalidade. Com o uso de ferramentas associadas à análise fractal e em potência, detectam-se vários comportamentos: uma reversão dos rendimentos (expoente de Hurst de 0,39 e dimensão fractal de 1,61), ciclos que são múltiplos de sete dias, inexistência de variância populacional, mudanças assimétricas, alta probabilidade de ocorrência de valores extremos e bom ajuste à distribuição α-estável. Esses comportamentos destacam a necessidade de elaborar métodos que incorporem os elementos necessários para analizar sistemas dinâmicos não lineares

“Staging, restaging and treatment response assessment” in lymphomas: what we should know.

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Comparison of an alternative and existing binning methods to reduce the acquisition duration of 4D PET/CT

International audiencePurpose: Respiratory motion is a source of artifacts that reduces image quality in PET. Four dimensional (4D) PET/CT is one approach to overcome this problem. Ex- isting techniques to limiting the eects of respiratory motions are based on prospec- tive phase binning which requires a long acquisition duration (15-25 min). This time is uncomfortable for the patients and limits the clinical exploitation of 4D PET/CT. In this work, we evaluated an existing and an alternative retrospective binning meth- ods to reduce the acquisition duration of 4D PET/CT. Methods: We studied an existing mixed-amplitude binning (MAB) and an alterna- tive binning method by mixed-phases binning (MPhB). Before implementing MPhB, we analyzed the regularity of the breathing patterns in patients. We studied the breathing signal drift and missing CT slices that could be challenging for implement- ing MAB. We compared the performance of MAB and MPhB with current binning methods to measure the maximum uptake, internal volume and maximal range of tumour motion. Results: MPhB can be implemented depending on an optimal phase (in average the exhalation peak phase - 4:1% of the entire breathing cycle duration). Signal drift of patients was in average 35% relatively to the breathing amplitude. Even after correcting this drift, MAB was feasible in 4D CT for only 64% of patients. No sig- nicant dierences appeared between the dierent binning methods to measure the maximum uptake, internal volume and maximal range of tumour motion. We also determined the inaccuracies of MAB and MPhB to measure the maximum amplitude of tumour motion with 3 bins (less than 3 mm for movement inferior to 12 mm, up to 6:4 mm for a 21 mm movement). Conclusions: We proposed an alternative binning method by mixed-phase binning that halves the acquisition duration of 4D PET/CT. Mixed-amplitude binning was challenging because of signal drift and missing CT slices. We showed that more than 3 bins were necessary for a more accurate measurement of the maximum amplitude of the tumour motion. However, the current 4D-CT technology limits the increase of the number of bins in 4D PET/CT because of missing CT slices. One can reconstruct 4D PET images with more bins but without attenuation/scatter correction

Importance of cholesterol and oxysterols metabolism in the pharmacology of tamoxifen and other AEBS ligands.

International audienceTamoxifen is one of the major drugs used for the hormonotherapy of estrogen receptor positive breast cancers. However, its therapeutic efficacy can be limited by acquired resistance and tumor recurrence can occur after several years of treatment. Tamoxifen is known as the prototypical modulator of estrogen receptors, but other targets have been identified that could account for its pharmacology. In particular, tamoxifen binds with high affinity to the microsomal antiestrogen binding site (AEBS) and inhibits cholesterol esterification at therapeutic doses. We have recently shown that the AEBS was a hetero-oligomeric complex composed of 3β-hydroxysterol-Δ(8)-Δ(7)-isomerase and 3β-hydroxysterol-Δ(7)-reductase, that binds different structural classes of ligands, including selective estrogen receptor modulators, several sigma receptor ligands, poly-unsaturated fatty acids and ring B oxysterols. We established a link between the modulation of cholesterol metabolism by tamoxifen and other AEBS ligands and their capacity to induce breast cancer cell differentiation, apoptosis and autophagy. Moreover, we showed that the AEBS carries out cholesterol-5,6-epoxide hydrolase activity and established that cholesterol-5,6-epoxide hydrolase is a new target for tamoxifen and other AEBS ligands. Finally in this review, we report on recent data from the literature showing how the modulation of cholesterol and oxysterol metabolism can be linked to the antitumor and chemopreventive properties of tamoxifen, and give new perspectives to improve the clinical outcome of the hormonotherapy of breast cancers

The Cholesterol-5,6-Epoxide Hydrolase: A Metabolic Checkpoint in Several Diseases

International audienceCholesterol-5,6-epoxides (5,6-ECs) are oxysterols (OS) that have been linked to several pathologies including cancers and neurodegenerative diseases. 5,6-ECs can be produced from cholesterol by several mechanisms including reactive oxygen species, lipoperoxidation, and cytochrome P450 enzymes. 5,6-ECs exist as two different diastereoisomers: 5,6α-EC and 5,6β-EC with different metabolic fates. They can be produced as a mixture or as single products of epoxidation. The epoxide ring of 5,6α-EC and 5,6β-EC is very stable and 5,6-ECs are prone to hydration by the cholesterol-5,6-epoxide hydrolase (ChEH) to give cholestane-3β,5α,6β-triol, which can be further oxidized into oncosterone. 5,6α-EC is prone to chemical and enzymatic conjugation reactions leading to bioactive compounds such as dendrogenins, highlighting the existence of a new metabolic branch on the cholesterol pathway centered on 5,6α-EC. We will summarize in this chapter current knowledge on this pathway which is controlled by the ChEH

Descriptive analysis of the French NS-Park registry: Towards a nation-wide Parkinson's disease cohort?

International audienceIntroduction: Parkinson's disease (PD) is the second most common neurodegenerative disorder after Alzheimer's. The French clinical research network for PD (NS-Park) has created a national patient registry to i)report medical activity of Parkinson Expert Centers (PECs) to the Ministry of Health, ii)facilitate PD patients pre-screening for clinical trials, iii) provide a source for pharmaco-epidemiology studies.Objective: Assess the French Parkinsonian population at a nation-wide level and discover new clinical characteristics.Methods: In this feasibility study, PECs prospectively collected clinical data in a standardized manner. The population main clinical characteristics are described, focusing on motor and non-motor symptoms and treatments, assessing its representativeness. By using an unbiased clustering with multiple correspondence analysis (MCA), we also investigate potential relationships between multiple variables like symptoms and treatments, as clues for future studies.Results: Between 2012 and 2016, among 11,157 included parkinsonian syndromes, 9454 (85%) had PD. MCA identified various profiles depending on disease duration. Occurrences of motor complications, axial signs, cognitive disorders and Levodopa use increase over time. Neurovegetative symptoms, psychiatric disorders, sleep disturbances and impulse control disorders (ICDs) seem stable over time. As expected, ICDs were associated to dopaminergic agonist use but other associations, such as ICDs and sleep disturbances for instance, or anxiety and depression, were found.Conclusions: Our results report one of the biggest PD registries ever reported and demonstrate the feasibility of implementing a nation-wide registry of PD patients in France, a potent tool for future longitudinal studies and clinical trials' population selection, and for pharmaco-epidemiology and cost-effectiveness studies

Interobserver agreement of qualitative analysis and tumor delineation of FMISO and FLT PET-images in lung cancer.

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Interobserver agreement of qualitative analysis and tumor delineation of FMISO and FLT PET-images in lung cancer.

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