Relativistically into finance

The change of information near the light speed, advances in high-speed trading, spatial arbitrage strategies and foreseen space exploration, suggest the need to consider the effects of the theory of relativity into finance models. Time and space, under certain circumstances, are not dissociated and no longer can be interpreted as Euclidean. This paper provides an overview of research made on this field, while formally defining the key notions of spacetime and proper time. Further progression in this field does require a common ground of concepts and an understanding of how time dilation impacts financial models. For illustration purposes, we compute relativistic effects for option prices when viewed from the viewpoint of two distinct reference frames, based upon the classical Balck-Scholes model. We show relativistic effects are non-negligible and illustrate how they depend on option characteristics such as maturity of the contract and volatility of the underlying.info:eu-repo/semantics/publishedVersio

On path–dependency of constant proportion portfolio insurance strategies

This paper evaluates the path–dependency/independency of most widespread Portfolio Insurance strategies. In particular, we look at Constant Proportion Portfolio Insurance (CPPI) structures and compare them to both the classical Option Based Portfolio Insurance (OBPI) and naive strategies such as Stop-loss Portfolio Insurance (SLPI) or a CPPI with a multiplier of one. The paper is based upon conditional Monte Carlo simulations and we show that CPPI strategies with a multiplier higher than 1 are extremely path-dependent and that they can easily get cash-locked, even in scenarios when the underlying at maturity can be worth much more than initially. The likelihood of being cash-locked increases with the size of the multiplier and the maturity of the CPPI, as well as with properties of the risky underlying’s dynamics. To emphasize the path dependency of CPPIs, we show that even in scenarios where the investor correctly “guesses” a higher future value for the underlying, CPPIs can get cash locked, losing the linkage to the risky asset. This cash-lock problem is specific of CPPIs, it goes against its European-style nature of traded CPPIs, and it introduces into the strategy a risks not related to the underlying risky asset – a design risk. Design risk does not occur for path-independent portfolio insurance strategies, like the classical case of OBPI strategies, nor in naive strategies. This study contributes to reinforce the idea that CPPI strategies suffer from a serious design problem.info:eu-repo/semantics/publishedVersio

Reciprocating wear tests of Al–Si/SiCp composites: a study of the effect of stroke length

The aim of the work described here was to find evidence for the influence of stroke length on the reciprocating wear of aluminium matrix composites. For this purpose, two kinds of tests were performed: reciprocating ball-on-plane geometry experiments to apply stroke in the millimetre range, and fretting tests to study the strokes in the micrometer scale. The relationships between the dissipated energy and the wear volume were established to compare these two different scale tests. The results are discussed in terms of energy approach and of the comparison of the wear mechanisms observed on the wear scars resulting from both tests

Multi-objective evolutionary algorithms for feature selection : application in bankruptcy prediction

A Multi-Objective Evolutionary Algorithm (MOEA) was adapted in order to deal with problems of feature selection in datamining. The aim is to maximize the accuracy of the classifier and/or to minimize the errors produced while minimizing the number of features necessary. A Support Vector Machines (SVM) classifier was adopted. Simultaneously, the parameters required by the classifier were also optimized. The validity of the methodology proposed was tested in the problem of bankruptcy prediction using a database containing financial statements of 1200 medium sized private French companies. The results produced shown that MOEA is an efficient feature selection approach and the best results were obtained when the accuracy, the errors and the classifiers parameters are optimized.The financial support of the Portuguese science foundation (FCT) under grant PTDC/GES/70168/2006 is acknowledged

Feature selection for bankruptcy prediction: a multi-objective optimization approach

In this work a Multi-Objective Evolutionary Algorithm (MOEA) was applied for feature selection in the problem of bankruptcy prediction. The aim is to maximize the accuracy of the classifier while keeping the number of features low. A two-objective problem - minimization of the number of features and accuracy maximization – was fully analyzed using two classifiers, Logistic Regression (LR) and Support Vector Machines (SVM). Simultaneously, the parameters required by both classifiers were also optimized. The validity of the methodology proposed was tested using a database containing financial statements of 1200 medium sized private French companies. Based on extensive tests it is shown that MOEA is an efficient feature selection approach. Best results were obtained when both the accuracy and the classifiers parameters are optimized. The method proposed can provide useful information for the decision maker in characterizing the financial health of a company

Early pathogen recognition and antioxidant system activation contributes to actinidia arguta tolerance against pseudomonas syringae pathovars actinidiae and actinidifoliorum

Actinidia chinensis and A. arguta have distinct tolerances to Pseudomonas syringae pv. actinidiae (Psa), but the reasons underlying the inter-specific variation remain unclear. This study aimed to integrate the metabolic and molecular responses of these two kiwifruit species against the highly pathogenic Psa and the less pathogenic P. syringae pv. actinidifoliorum (Pfm) bacterial strains. Disease development was monitored weekly till 21 days post inoculation (dpi), analysing a broad number and variety of parameters including: colony forming units (CFU), foliar symptoms, total chlorophylls, lipid peroxidation, soluble polyphenols, lignin and defense-related gene expression. At the end of the experimental period A. chinensis inoculated with Psa presented the highest endophytic bacterial population, whereas A. arguta inoculated with Pfm showed the lowest values, also resulting in a lower extent of leaf symptoms. Metabolic responses to infection were also more pronounced in A. chinensis with decreased total chlorophylls (up to 55%) and increased lipid peroxidation (up to 53%), compared with non-inoculated plants. Moreover, at 14 dpi soluble polyphenols and lignin concentrations were significantly higher (112 and 26%, respectively) in Psa-inoculated plants than in controls, while in A. arguta no significant changes were observed in those metabolic responses, except for lignin concentration which was, in general, significantly higher in Psa-inoculated plants (by at least 22%), comparing with control and Pfm-inoculated plants. Genes encoding antioxidant enzymes (SOD, APX and CAT) were upregulated at an earlier stage in Psa-inoculated A. arguta than in A. chinensis. In contrast, genes related with phenylpropanoids (LOX1) and ethylene (SAM) pathways were downregulated in A. arguta, but upregulated in A. chinensis in the later phases of infection. Expression of Pto3, responsible for pathogen recognition, occurred 2 dpi in A. arguta, but only 14 dpi in A. chinensis. In conclusion, we found that A. arguta is more tolerant to Psa and Pfm infection than A. chinensis and its primary and secondary metabolism is less impacted. A. arguta higher tolerance seems to be related with early pathogen recognition, the activation of plant antioxidant system, and to the suppression of ET and JA pathways from an earlier moment after infection.info:eu-repo/semantics/publishedVersio

A step forward

Funding: Authors gratefully acknowledge Fundação para a Ciência e a Tecnologia (FCT) through projects UIDB/00645/2020, UIDB/04138/2020, PTDC/MED-QUI/31721/2017, UIDP/04138/2020 and Lusófona University, ULHT. Authors are also thankful to FCT/MCTES for the financial support to CESAM (UIDP/50017/2020, UIDB/50017/2020), through national funds.Anaplastic thyroid carcinoma (ATC) is a very rare subtype of thyroid carcinoma and one of the most lethal malignancies. Poor prognosis is mainly associated with its undifferentiated nature, inoperability, and failing to respond to the typically used therapies for thyroid cancer. Photothermal Therapy (PTT) entails using light to increase tissues’ temperature, leading to hyperthermia-mediated cell death. Tumours are more susceptible to heat as they are unable to dissipate it. By using functionalized gold nanoparticles (AuNPs) that transform light energy into heat, it is possible to target the heat to the tumour. This study aims to formulate ATC-targeted AuNPs able to convert near-infrared light into heat, for PTT of ATC. Different AuNPs were synthetized and coated. Size, morphology, and surface plasmon resonances band were determined. The optimized coated-AuNPs were then functionalized with ligands to assess ATC’s specificity. Safety, efficacy, and selectivity were assessed in vitro. The formulations were deemed safe when not irradiated (>70% cell viability) and selective for ATC. However, when irradiated, holo-transferrin-AuNPs were the most cytotoxic (22% of cell viability). The biodistribution and safety of this formulation was assessed in vivo. Overall, this novel formulation appears to be a highly promising approach to evaluate in a very near future.publishersversionpublishe

A Common Variant in the CDK8 Gene Is Associated with Sporadic Pituitary Adenomas in the Portuguese Population: a Case-Control Study

The majority of pituitary adenomas occur in a sporadic context, and in the absence of known genetic predisposition. Three common variants at the NEBL (rs2359536), PCDH15 (rs10763170) and CDK8 (rs17083838) loci were previously associated with sporadic pituitary adenomas in the Han Chinese population, but these findings have not yet been replicated in any other population. The aim of this case-control study was to assess if these variants are associated with susceptibility to sporadic pituitary adenomas in the Portuguese population. Genotype and allele frequencies were determined in 570 cases and in 546 controls. The CDK8 rs17083838 minor allele (A allele) was significantly associated with sporadic pituitary adenomas, under an additive (odds ratio (OR) 1.73, 95% confidence interval (CI) 1.19-2.50, p = 0.004) and dominant (OR 1.82, 95% CI 1.24-2.68, p = 0.002) inheritance model. The NEBL rs2359536 and PCDH15 rs10763170 variants were not associated with the overall risk for the disease, although a borderline significant association was observed between the PCDH15 rs10763170 minor allele (T allele) and somatotrophinomas (dominant model, OR 1.55, 95% CI 1.02-2.35, p = 0.035). These findings suggest that the CDK8 rs17083838 variant, and possibly the PCDH15 rs10763170 variant, may increase susceptibility to sporadic pituitary adenomas in the Portuguese population.info:eu-repo/semantics/publishedVersio

Cultivo celular e extração de fosfolipídios para composição de nanossistemas imunomoduladores.

A infestação por carrapatos traz vários prejuízos a pecuária brasileira. Dessa forma, objetivou desenvolver nanossistemas imunomoduladores através de nanopartículas lipossomais para reprogramação metabólica de células específicas do sistema imune bovino combater infestação por carrapatos. Para isso, foi feita a extração de fosfolipídios de macrófagos. Durante o cultivo celular dos macrófagos ocorreram sucessivas contaminações das células não sendo possível ter uma eficiente extração de fosfolipídios. Mais estudos precisam ser realizados para amplificação da obtenção dos fosfolipídios e criação de nanossistemas para imunização de uma quantidade maior de animais