4,381 research outputs found

    Genetic algorithm in chemistry.

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    Genetic algorithm is an optimization technique based on Darwin evolution theory. In last years its application in chemistry is increasing significantly due the special characteristics for optimization of complex systems. The basic principles and some further modifications implemented to improve its performance are presented, as well as a historical development. A numerical example of a function optimization is also shown to demonstrate how the algorithm works in an optimization process. Finally several chemistry applications realized until now is commented to serve as parameter to future applications in this field.22340541

    Numerical modelling of the dynamic response of liquefiable deposits in the presence of small scale buildings

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    The impact of liquefaction in building performance during earthquakes is an aspect that has been recently receiving more attention by the technical and scientific communities, in an attempt to reduce the vulnerability of structures located in loose sandy saturated deposits. Currently, the design of buildings in liquefiable layers is performed based on empirical rules, where the liquefaction potential and the ground settlements are usually assessed free-field conditions, i.e., neglecting the presence of the surface structures. Even in the probabilistic approaches that tend to incorporate Earthquake Liquefaction Induced Damages (ELID) from some case-histories that include buildings at the surface, have never incorporated foundations characteristics and loading conditions. However, recent advances in numerical modelling allow performing a more rigorous assessment of the effects induced by liquefaction, namely the settlements that are expected to occur in the spread footings of structures, one of the most common foundation system implemented in small-to-mid-rise constructions in Europe. Therefore, the present paper focuses research on the assessment of the settlements due to earthquake-induced liquefaction that is being conducted within the European Project LIQUEFACT

    Fatty acids profile of pulp and nuts of brazilian fruits

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    Fruits and nuts from the North and Northeast regions of Brazil were collected to determine the fatty acid profile of their oils. The species studied were Brazil (Bertholletia excelsa H. B. K.), Mucaja (Couma rigida M.), Inaja (Maximiliana maripa D.), Jenipapo (Genipa Americana L.), and Buriti (Mauritia flexuosa L.) nuts. Fatty acid methyl esters were analyzed by gas chromatography with flame ionization detection (GC-FID). Brazil nut major fatty acid was 18:3n-3 (alpha-linolenic acid), and Buriti nut had approximately 23 times more 18: 3n-3 than the pulp. Mucaja nut presented high content of 12: 0 (lauric acid) and 16: 0 (palmitic acid), and Mucaja pulp showed significant levels of 18: 2n-6 (linoleic acid). Considering the PUFA (polyunsaturated fatty acid) sum values, almost all fruits and nuts analyzed presented very high levels of these compounds. Regarding n-6/n-3 ratio, only Brazil Nut, Buriti Nut, Inaja pulp, and Jenipapo pulp corresponded to the desired profile. These Brazilian fruits and nuts could be of potential interest due to their high nutritive value and lipid content.31495095

    Divergent mathematical treatments in utility theory

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    In this paper I study how divergent mathematical treatments affect mathematical modelling, with a special focus on utility theory. In particular I examine recent work on the ranking of information states and the discounting of future utilities, in order to show how, by replacing the standard analytical treatment of the models involved with one based on the framework of Nonstandard Analysis, diametrically opposite results are obtained. In both cases, the choice between the standard and nonstandard treatment amounts to a selection of set-theoretical parameters that cannot be made on purely empirical grounds. The analysis of this phenomenon gives rise to a simple logical account of the relativity of impossibility theorems in economic theory, which concludes the paper

    Decision Making for Inconsistent Expert Judgments Using Negative Probabilities

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    In this paper we provide a simple random-variable example of inconsistent information, and analyze it using three different approaches: Bayesian, quantum-like, and negative probabilities. We then show that, at least for this particular example, both the Bayesian and the quantum-like approaches have less normative power than the negative probabilities one.Comment: 14 pages, revised version to appear in the Proceedings of the QI2013 (Quantum Interactions) conferenc

    High Levels of Heavy Metal(loid)s Related to Biliary Hyperplasia in Hedgehogs (Erinaceus europaeus)

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    Simple Summary Heavy metal(loid)s are hazardous substances for humans, animals and ecosystems. The liver is one of the most affected organs, presenting lesions after being acutely or chronically exposed to these substances. In this study, hepatic metal(loid)s' concentrations were associated with biliary hyperplasia, which was the most common hepatic lesion found in a group of western-European hedgehogs from rescue centres in Portugal. With exception of arsenic (As), all metal(loid)s were present in higher concentrations in animals with biliary hyperplasia. Further research is necessary to support these results and clarify the molecular mechanisms that lead to hepatic lesions provoked by these compounds. Heavy metal(loid) pollution of ecosystems is a current One Health problem. The liver is one of the most affected organs in cases of acute or chronic exposure to abnormal amounts of these substances, inducing histopathologic lesions. In order to assess the influence of heavy metal(loids), forty-five European hedgehogs (Erinaceus europaeus) were submitted to necropsy, and liver samples were collected for a routine histopathology exam and metal(loid)s determination (As, Cd, Co, Cr, Cu and Pb) by ICP-MS. Age was estimated during the necropsy exam. Biliary hyperplasia was the most frequent lesion observed (16/45; 35.56%). No statistically significant associations were found between biliary hyperplasia and age or sex. Metal(loid)s' concentrations were higher in animals with biliary hyperplasia (except for As). There was a statistically significant difference for both Cd and Co. For As, Cd and Co, cubs and juveniles animals showed significantly lower concentrations than elder individuals. Only for Pb were significant differences found between females and males. As described in the literature, exposure to metal(loid)s may be a cause of biliary hyperplasia, although further research (including the use of biochemical methods) is needed to support these results. To the authors' knowledge, this is the first report of this association in hedgehogs.This work was supported by National Funds by the Portuguese Foundation for Science and Technology (FCT). The authors of the research unit CITAB (CJB and PAO) received funding from FCT-reference of the project: UIDB/04033/2020. The author of the research unit CECAV (FS) received funding from FCT-reference of the project: UIDB/CVT/00772/2020. CJB was supported by FCT due to the phD scholarship 2021.04520.BD. TLM was supported by UIDB/CVT/00772/2020 and LA/P/0059/2020 funded by FCT

    Vav proteins are key regulators of Card9 signaling for innate antifungal immunity

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    Fungal infections are major causes of morbidity and mortality, especially in immunocompromised individuals. The innate immune system senses fungal pathogens through Syk-coupled C-type lectin receptors (CLRs), which signal through the conserved immune adaptor Card9. Although Card9 is essential for antifungal defense, the mechanisms that couple CLR-proximal events to Card9 control are not well defined. Here, we identify Vav proteins as key activators of the Card9 pathway. Vav1, Vav2, and Vav3 cooperate downstream of Dectin-1, Dectin-2, and Mincle to engage Card9 for NF-κB control and proinflammatory gene transcription. Although Vav family members show functional redundancy, Vav1/2/3(-/-) mice phenocopy Card9(-/-) animals with extreme susceptibility to fungi. In this context, Vav3 is the single most important Vav in mice, and a polymorphism in human VAV3 is associated with susceptibility to candidemia in patients. Our results reveal a molecular mechanism for CLR-mediated Card9 regulation that controls innate immunity to fungal infections

    Early and Middle Holocene Hunter-Gatherer Occupations in Western Amazonia: The Hidden Shell Middens

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    We report on previously unknown early archaeological sites in the Bolivian lowlands, demonstrating for the first time early and middle Holocene human presence in western Amazonia. Multidisciplinary research in forest islands situated in seasonally-inundated savannahs has revealed stratified shell middens produced by human foragers as early as 10,000 years ago, making them the oldest archaeological sites in the region. The absence of stone resources and partial burial by recent alluvial sediments has meant that these kinds of deposits have, until now, remained unidentified. We conducted core sampling, archaeological excavations and an interdisciplinary study of the stratigraphy and recovered materials from three shell midden mounds. Based on multiple lines of evidence, including radiocarbon dating, sedimentary proxies (elements, steroids and black carbon), micromorphology and faunal analysis, we demonstrate the anthropogenic origin and antiquity of these sites. In a tropical and geomorphologically active landscape often considered challenging both for early human occupation and for the preservation of hunter-gatherer sites, the newly discovered shell middens provide evidence for early to middle Holocene occupation and illustrate the potential for identifying and interpreting early open-air archaeological sites in western Amazonia. The existence of early hunter-gatherer sites in the Bolivian lowlands sheds new light on the region's past and offers a new context within which the late Holocene "Earthmovers" of the Llanos de Moxos could have emerged. © 2013 Lombardo et al
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