1,233 research outputs found

    Surrogate-based optimization of tidal turbine arrays: a case study for the Faro-OlhĂŁo inlet

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    This paper presents a study for estimating the size of a tidal turbine array for the Faro-OlhĂŁo Inlet (Potugal) using a surrogate optimization approach. The method compromises problem formulation, hydro-morphodynamic modelling, surrogate construction and validation, and constraint optimization. A total of 26 surrogates were built using linear RBFs as a function of two design variables: number of rows in the array and Tidal Energy Converters (TECs) per row. Surrogates describe array performance and environmental effects associated with hydrodynamic and morphological aspects of the multi inlet lagoon. After validation, surrogate models were used to formulate a constraint optimization model. Results evidence that the largest array size that satisfies performance and environmental constraints is made of 3 rows and 10 TECs per row.Eduardo GonzĂĄlez-Gorbeña has received funding for the OpTiCA project (http://msca-optica.eu/) from the Marie SkƂodowska-Curie Actions of the European Union's H2020-MSCA-IF-EF-RI-2016 / GA#: 748747. The paper is a contribution to the SCORE pro-ject, funded by the Portuguese Foundation for Science and Technology (FCT–PTDC/AAG-TEC/1710/2014). AndrĂ© Pacheco was supported by the Portuguese Foun-dation for Science and Technology under the Portuguese Researchers’ Programme 2014 entitled “Exploring new concepts for extracting energy from tides” (IF/00286/2014/CP1234).info:eu-repo/semantics/publishedVersio

    Mathematical modeling tendencies in plant pathology

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    Nowadays plant diseases represent one of the major threats for crops around the world, because they carry healthy, economical, environmental and social problems. Considering this, it is necessary to have a description of the dynamics of plant disease in order to have sustainable strategies to prevent and diminish the impact of the diseases in crops. Mathematical tools have been employed to create models which give a description of epidemic dynamics; the commonly mathematical tools used are: Diseaseprogress curves, Linked Differential Equation (LDE), Area Under disease Progress Curve (AUDPC) and computer simulation. Nevertheless, there are other tools that have been employed in epidemiology of plant disease like: statistical tools, visual evaluations and pictorial assessment. Each tool has its own advantages and disadvantages. The nature of the problem and the epidemiologist necessities determine the mathematical tool to be used and the variables to be included into the model. This paperpresents review of the tools used in epidemiology of plant disease remarking their advantages and disadvantages and mathematical modeling tendencies in plant pathology

    Cross-protection between attenuated Plasmodium berghei and P. yoelii sporozoites

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    An attenuatedPlasmodium falciparum sporozoite (PfSPZ) vaccine is under development, in part, based on studies in mice withP. berghei. We usedP. berghei andP. yoelii to study vaccine-induced protection against challenge with a species of parasite different from the immunizing parasite in BALB/c mice. One-hundred percent of mice were protected against homologous challenge. Seventy-nine percent immunized with attenuatedP. berghei sporozoite (PbSPZ)(six experiments) were protected against challenge withP. yoelii sporozoite (PySPZ), and 63% immunized with attenuatedPySPZ(three experiments) were protected against challenge withPbSPZ. Antibodies in sera of immunized mice only recognized homologous sporozoites and could not have mediated protection against heterologous challenge. Immunization with attenuatedPySPZ orPbSPZ induced CD8+ T cell-dependent protection against heterologous challenge. Immunization with attenuatedPySPZ induced CD8+ T cell-dependent protection against homologous challenge. However, homologous protection induced by attenuatedPbSPZ was not dependent on CD8+ or CD4+ T cells, and depletion of both populations only reduced protection by 36%. Immunization of C57BL/10 mice withPbSPZ induced CD8+ T cell-dependent protection againstP. berghei, but no protection againstP. yoelii. The cross-protection data in BALB/c mice support testing a human vaccine based on attenuatedPfSPZ for its efficacy againstP. vivax

    Learning and innovative elements of strategy adoption rules expand cooperative network topologies

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    Cooperation plays a key role in the evolution of complex systems. However, the level of cooperation extensively varies with the topology of agent networks in the widely used models of repeated games. Here we show that cooperation remains rather stable by applying the reinforcement learning strategy adoption rule, Q-learning on a variety of random, regular, small-word, scale-free and modular network models in repeated, multi-agent Prisoners Dilemma and Hawk-Dove games. Furthermore, we found that using the above model systems other long-term learning strategy adoption rules also promote cooperation, while introducing a low level of noise (as a model of innovation) to the strategy adoption rules makes the level of cooperation less dependent on the actual network topology. Our results demonstrate that long-term learning and random elements in the strategy adoption rules, when acting together, extend the range of network topologies enabling the development of cooperation at a wider range of costs and temptations. These results suggest that a balanced duo of learning and innovation may help to preserve cooperation during the re-organization of real-world networks, and may play a prominent role in the evolution of self-organizing, complex systems.Comment: 14 pages, 3 Figures + a Supplementary Material with 25 pages, 3 Tables, 12 Figures and 116 reference

    Effect of Ambrotose AOÂź on resting and exercise-induced antioxidant capacity and oxidative stress in healthy adults

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    <p>Abstract</p> <p>Background</p> <p>The purpose of this investigation was to determine the effects of a dietary supplement (Ambrotose AO<sup>Âź</sup>) on resting and exercise-induced blood antioxidant capacity and oxidative stress in exercise-trained and untrained men and women.</p> <p>Methods</p> <p>25 individuals (7 trained and 5 untrained men; 7 trained and 6 untrained women) received Ambrotose AO<sup>Âź </sup>(4 capsules per day = 2 grams per day) or a placebo for 3 weeks in a random order, double blind cross-over design (with a 3 week washout period). Blood samples were collected at rest, and at 0 and 30 minutes following a graded exercise treadmill test (GXT) performed to exhaustion, both before and after each 3 week supplementation period. Samples were analyzed for Trolox Equivalent Antioxidant Capacity (TEAC), Oxygen Radical Absorbance Capacity (ORAC), malondialdehyde (MDA), hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>), and nitrate/nitrite (NOx). Quality of life was assessed using the SF-12 form and exercise time to exhaustion was recorded. Resting blood samples were analyzed for complete blood count (CBC), metabolic panel, and lipid panel before and after each 3 week supplementation period. Dietary intake during the week before each exercise test was recorded.</p> <p>Results</p> <p>No condition effects were noted for SF-12 data, for GXT time to exhaustion, or for any variable within the CBC, metabolic panel, or lipid panel (p > 0.05). Treatment with Ambrotose AO<sup>Âź </sup>resulted in an increase in resting levels of TEAC (p = 0.02) and ORAC (p < 0.0001). No significant change was noted in resting levels of MDA, H<sub>2</sub>O<sub>2</sub>, or NOx (p > 0.05). Exercise resulted in an acute increase in TEAC, MDA, and H<sub>2</sub>O<sub>2 </sub>(p < 0.05), all which were higher at 0 minutes post exercise compared to pre exercise (p < 0.05). No condition effects were noted for exercise related data (p > 0.05), with the exception of ORAC (p = 0.0005) which was greater at 30 minutes post exercise for Ambrotose AO<sup>Âź </sup>compared to placebo.</p> <p>Conclusion</p> <p>Ambrotose AO<sup>Âź </sup>at a daily dosage of 4 capsules per day increases resting blood antioxidant capacity and may enhance post exercise antioxidant capacity. However, no statistically detected difference is observed in resting or exercise-induced oxidative stress biomarkers, in quality of life, or in GXT time to exhaustion.</p

    c-Fos induction by gut hormones and extracellular ATP in osteoblastic-like cell lines

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    It is widely accepted that the c-Fos gene has a role in proliferation and differentiation of bone cells. ATP-induced c-Fos activation is relevant to bone homeostasis, because nucleotides that are present in the environment of bone cells can contribute to autocrine/paracrine signalling. Gut hormones have previously been shown to have an effect on bone metabolism. In this study, we used the osteoblastic Saos-2 cell line transfected with a c-Fos-driven reporter stimulated with five gut hormones: glucose inhibitory peptide (GIP), glucagon-like peptide-1 (GLP-1), glucagon-like peptide-2 (GLP-2), ghrelin and obestatin, in the presence or absence of ATP. In addition, TE-85 cells were used to determine the time course of c-Fos transcript induction following stimulation with GLP-1, and GLP-2 with or without ATP, using reverse transcription qPCR. The significant results from the experiments are as follows: higher level of c-Fos induction in presence of GIP, obestatin (p = 0.019 and p = 0.011 respectively), and GIP combined with ATP (p < 0.001) using the luciferase assay; GLP-1 and GLP-2 combined with ATP (p = 0.034 and p = 0.002, respectively) and GLP-2 alone (p < 0.001) using qPCR. In conclusion, three of the gut peptides induced c-Fos, providing a potential mechanism underlying the actions of these hormones in bone which can be directed or enhanced by the presence of ATP

    Absence of system xc⁻ on immune cells invading the central nervous system alleviates experimental autoimmune encephalitis

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    Background: Multiple sclerosis (MS) is an autoimmune demyelinating disease that affects the central nervous system (CNS), leading to neurodegeneration and chronic disability. Accumulating evidence points to a key role for neuroinflammation, oxidative stress, and excitotoxicity in this degenerative process. System x(c)- or the cystine/glutamate antiporter could tie these pathological mechanisms together: its activity is enhanced by reactive oxygen species and inflammatory stimuli, and its enhancement might lead to the release of toxic amounts of glutamate, thereby triggering excitotoxicity and neurodegeneration. Methods: Semi-quantitative Western blotting served to study protein expression of xCT, the specific subunit of system x(c)-, as well as of regulators of xCT transcription, in the normal appearing white matter (NAWM) of MS patients and in the CNS and spleen of mice exposed to experimental autoimmune encephalomyelitis (EAE), an accepted mouse model of MS. We next compared the clinical course of the EAE disease, the extent of demyelination, the infiltration of immune cells and microglial activation in xCT-knockout (xCT(-/-)) mice and irradiated mice reconstituted in xCT(-/-) bone marrow (BM), to their proper wild type (xCT(+/+)) controls. Results: xCT protein expression levels were upregulated in the NAWM of MS patients and in the brain, spinal cord, and spleen of EAE mice. The pathways involved in this upregulation in NAWM of MS patients remain unresolved. Compared to xCT(+/+) mice, xCT(-/-) mice were equally susceptible to EAE, whereas mice transplanted with xCT(-/-) BM, and as such only exhibiting loss of xCT in their immune cells, were less susceptible to EAE. In none of the above-described conditions, demyelination, microglial activation, or infiltration of immune cells were affected. Conclusions: Our findings demonstrate enhancement of xCT protein expression in MS pathology and suggest that system x(c)- on immune cells invading the CNS participates to EAE. Since a total loss of system x(c)- had no net beneficial effects, these results have important implications for targeting system x(c)- for treatment of MS

    Tandem Mass Spectrometry Measurement of the Collision Products of Carbamate Anions Derived from CO2 Capture Sorbents: Paving the Way for Accurate Quantitation

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    The reaction between CO2 and aqueous amines to produce a charged carbamate product plays a crucial role in post-combustion capture chemistry when primary and secondary amines are used. In this paper, we report the low energy negative-ion CID results for several anionic carbamates derived from primary and secondary amines commonly used as post-combustion capture solvents. The study was performed using the modern equivalent of a triple quadrupole instrument equipped with a T-wave collision cell. Deuterium labeling of 2-aminoethanol (1,1,2,2,-d4-2-aminoethanol) and computations at the M06-2X/6-311++G(d,p) level were used to confirm the identity of the fragmentation products for 2-hydroxyethylcarbamate (derived from 2-aminoethanol), in particular the ions CN−, NCO− and facile neutral losses of CO2 and water; there is precedent for the latter in condensed phase isocyanate chemistry. The fragmentations of 2-hydroxyethylcarbamate were generalized for carbamate anions derived from other capture amines, including ethylenediamine, diethanolamine, and piperazine. We also report unequivocal evidence for the existence of carbamate anions derived from sterically hindered amines (Tris(2-hydroxymethyl)aminomethane and 2-methyl-2-aminopropanol). For the suite of carbamates investigated, diagnostic losses include the decarboxylation product (−CO2, 44 mass units), loss of 46 mass units and the fragments NCO− (m/z 42) and CN− (m/z 26). We also report low energy CID results for the dicarbamate dianion (−O2CNHC2H4NHCO2−) commonly encountered in CO2 capture solution utilizing ethylenediamine. Finally, we demonstrate a promising ion chromatography-MS based procedure for the separation and quantitation of aqueous anionic carbamates, which is based on the reported CID findings. The availability of accurate quantitation methods for ionic CO2 capture products could lead to dynamic operational tuning of CO2 capture-plants and, thus, cost-savings via real-time manipulation of solvent regeneration energies
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