3D printed ceramics structures - Challenges and applications

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Portfolio optimization with options

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Finance from the NOVA – School of Business and EconomicsIn order to address the options returns non normality problem in the investment portfolio theory, this work project aims to discuss and present alternatives to the classic Markowitz risk/return paradigm. The following pages will exploit the Portfolio Selection Theory developed over the last decade, maximizing a standard CRRA utility function, and simulating (MonteCarlo) or deriving from the past data (Bootstrap) the path taken by the S&P 500 stock Index. To conclude, a 5 year back test is developed to evidence the practical implications of the several models exposed

Potentiation of glucose-mediated glomerular injury by mechanical strain

1. The glomerular injury of diabetes is characterized by the progressive accumulation of extracellular matrix in the mesangial regions, ultimately resulting in glomerulosclerosis. 2. The excessive glomerular extracellular matrix formation associated with the haemodynamic alteration of diabetes is the result of mesangial mechanical strain. 3. The increased synthesis and deposition of extracellular matrix is augmented by the presence of high glucose concentrations. 4. Both mechanical strain and high glucose share many of the mechanisms mediating their metabolic effects, including the stimulation of prosclerotic growth factors. 5. Little is known about factors that may influence the long-term effects of mechanical strain, but the preservation of the F-actin cytoskeleton is likely an important modulator of the resulting injury

Analysis of some factors and COVID-19 mortality in the population of 0 to 24 years in 29 countries: open schools could be a protection

Background. It is limited literature on the possible factors related to mortality by COVID-19 in minors. Children and young people are generally considered vulnerable, especially in low-income countries, whereby consistent evidence must arise to protect them and avoid mortality. Methods. A multiple linear regression model was fit to evaluate the relationship between deaths per 100,000 inhabitants and pandemic containment policies, the duration of totally closed schools, and GDP in 29 countries under study. Results. Linear regression analysis shows that the association between deaths per 100k and the number of weeks of closed schools had a coef B=0.355, [CI 0.010; 0.699], and it is statistically significant (P-value =0.044). Similarly, the association between deaths per 100K and GDP was -0.001, [CI -0.003; 0.001], and is not statistically associated (P-value 0.633). Conclusions. This study suggests that open schools could be a protective space for COVID-19 mortality in the child and youth population and that each country should implement studies on the subject at the local level

Strong exchange rings

Altres ajuts: The first author is partially supported by the Spanish Government under grants PID2020-113552GB-I00, which include EU FEDER funds, and by the Junta de Andalucía under grant P20-00770. The second author is partially supported by the Spanish Government under grant PID2020-113206GB-I00/AEI/10.13039/501100011033, which includes EU FEDER funds, and by Fundación Séneca of Murcia under grant 19880/GERM/15.Two elements a, b in a ring R form a right coprime pair, written ha, bi, if aR + bR = R. Right coprime pairs have shown to be quite useful in the study of left cotorsion or exchange rings. In this paper, we define the class of right strong exchange rings in terms of descending chains of them. We show that they are semiregular and that this class of rings contains left injective, left pure-injective, left cotorsion, local, and left continuous rings. This allows us to give a unified study of all these classes of rings in terms of the behaviour of descending chains of right coprime pairs

De novo pyrimidine nucleotide biosynthesis in isolated rat glomeruli

De novo pyrimidine nucleotide biosynthesis in isolated rat glomeruli. Uracil ribonucleotide–sugars and aminosugars are required for glomerular basement membrane (GBM) biosynthesis. Since these nucleotides are metabolic derivatives of uridine 5′-triphosphate (UTP), we have studied the cellular pools of uridine 5′-diphosphoglucose (UDPG), uridine 5′-diphosphoglucuronic acid (UDPGA), uridine 5′-diphospho-N-acetyl glucosamine (UDPAG) and UTP, and measured UTP synthesis de novo in isolated glomeruli incubated in vitro. Improved techniques for nucleotide quantitation were established and the optimal conditions for glomerular isolation and incubation determined. Substantial quantities of uracil ribonucleotide coenzymes and an active utilization of orotate for the synthesis of pyrimidine nucleotides were demonstrated. UTP synthesis and the pools of UDPG and UDPG A varied markedly with changes in the experimental conditions. The adverse effects of suboptimal conditions were more apparent in glomeruli from diabetic animals than in controls. The use of suboptimal conditions could provide misleading information on GBM metabolism in isolated glomeruli since uracil ribonucleotide coenzyme availability might be reduced

Exploring Low Internal Reorganization Energies for Silicene Nanoclusters

High-performance materials rely on small reorganization energies to facilitate both charge separation and charge transport. Here, we performed DFT calculations to predict small reorganization energies of rectangular silicene nanoclusters with hydrogen-passivated edges denoted by H-SiNC. We observe that across all geometries, H-SiNCs feature large electron affinities and highly stabilized anionic states, indicating their potential as n-type materials. Our findings suggest that fine-tuning the size of H-SiNCs along the zigzag and armchair directions may permit the design of novel n-type electronic materials and spinctronics devices that incorporate both high electron affinities and very low internal reorganization energies.Comment: 25 pages, 6 figure

Quasi-static and high strain rate response of aluminum matrix syntactic foams under compression

Aluminum alloy matrix syntactic foams were produced by inert gas pressure infiltration. Four different alloys and ceramic hollow spheres were applied as matrix and filler material, respectively. The effects of the chemical composition of the matrix and the different heat-treatments are reported at different strain-rates and in compressive loadings. The higher strain rates were performed in a Split-Hopkinson pressure bar system. The results show that, the characteristic properties of the materials strongly depends on the chemical composition of the matrix and its heat-treatment condition. The compressive strength of the investigated foams showed a limited sensitivity to the strain rate, its effect was more pronounced in the case of the structural stiffness and fracture strain. The failure modes of the foams have explicit differences showing barreling and shearing in the case of quasi-static and high strain rate compression respectively

One health defines an emerging sixth wave of public health development

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