Whether COVID-19 Infection Affects Human Cognitive Function

The COVID-19 pandemic, resulting from the SARS-CoV-2 virus, continues to impact the daily lives of individuals worldwide. Although research has been conducted on long-COVID symptoms, the underlying causes remain unclear. Notably, instances of neurological decline have been observed following SARS-CoV-2 infections. 125,573 articles regarding neurological damage and cognitive disfunction were published and can be found from major research databases. For this scholarly project, 25 peer-reviewed journal articles pertaining to long-COVID and neurologic function changes, as well as potential underlying reasons for these changes, were curated. The proposed hypotheses include the virus\u27 ability to pass through and harm the blood-brain barrier and neuronal cells, the release of neurochemicals associated with the SARS-CoV-2 antibody spike protein, as well as vascular ischemia, hypoxia of the brain, and other organs. Urgent attention is required to conduct further research on the treatment of chronic neurologic function changes resulting from long-COVID

The Asset Cost of Poor Health

This paper examines the correlation between poor health and asset accumulation for households in the first nine waves of the Health and Retirement Survey. Rather than enumerating the specific costs of poor health, such as out of pocket medical expenses or lost earnings, we estimate how the evolution of household assets is related to poor health. We construct a simple measure of health status based on the first principal component of HRS survey responses on self-reported health status, diagnoses, ADLs, IADL, and other indicators of underlying health. Our estimates suggest large and substantively important correlations between poor health and asset accumulation. We compare persons in each 1992 asset quintile who were in the top third of the 1992 distribution of latent health with those in the same 1992 asset quintile who were in the bottom third of the latent health distribution. By 2008, those in the top third of the health distribution had accumulated, on average, more than 50 percent more assets than those in the bottom third of the health distribution. This “asset cost of poor health” appears to be larger for persons with substantial 1992 asset balances than for those with lower balances

The Drawdown of Personal Retirement Assets

How households draw down the balances that they accumulate in retirement saving accounts such as 401(k) plans and Individual Retirement Accounts can have an important effect on the contribution of these accounts to retirement income security. This paper presents evidence on the pattern of withdrawals at different ages. We find a relatively modest rate of withdrawals prior to the age at which households are required to take minimum required distributions. Only seven percent of PRA-owning households between the ages of 60 and 69 take annual distributions of more than ten percent of their PRA balance, and only 18 percent of PRA households in this age group make any withdrawals in a typical year. The rate of distributions rises sharply after age 70 ½, when minimum distributions are required. The proportion of PRA-owning households making a withdrawal jumps to over 60 percent by age 71, and crosses 70 percent a few years later. On average, households age 60 to 69 with PRA accounts withdraw only about two percent of their account balances each year, considerably less than the rate of return on account balances during our sample period. Even at older ages—after the required minimum distribution age--the percentage of balances withdrawn remains at about five percent

The impact of resilience among older adults

AbstractThe purpose of this literature review was to provide an overview of resilience for the purpose of informing potential intervention designs that may benefit older adults. While numerous reviews have focused on various specific aspects of resilience, none have provided the necessary information required to design an effective resilience intervention. Research examining resilience suggests that older adults are capable of high resilience despite socioeconomic backgrounds, personal experiences, and declining health. Thus opportunities to inform interventions in this area exist. Research studies have identified the common mental, social, and physical characteristics associated with resilience. High resilience has also been significantly associated with positive outcomes, including successful aging, lower depression, and longevity. Interventions to enhance resilience within this population are warranted, but little evidence of success exists. Thus this review provides an overview of resilience that may aid in the design of resilience interventions for the often underserved population of older adults

Numerical investigations of Piston mode resonance in a moonpool using OpenFOAM

Moonpool dynamics is a complex phenomenon, and is part of a series of problems referred to as gap problems involving entrapped fluid in a small gap. The fluid in these gaps has an infinite number of resonance modes; a piston mode resonance in heave, and an infinite number of sloshing modes. The piston mode is often the most troublesome, and must be considered when designing a moonpool. A numerical verification is done on an experiment of a 2D section of a moonpool in shallow water. The numerical tool used will be OpenFOAM (http://www.openfoam.com/) by OpenCFD. The solver library interDyMFoam with dynamic meshing and free surface modeling using a Volume-Of-Fluid method will be used. Four different configurations of the moonpool will be assessed numerically, but only two will be compared to experimental data. Of these four design alternatives, it will be seen if OpenFoam accurately can describe the physics involved. Before assessing the moonpool case, a verification of a simpler case is done with the NACA0012 free surface experiment by Duncan (1983). This is done with interFoam. Good quantitative agreements were found in all cases; the resonance frequency was found in all cases with 3 digit accuracy. Qualitative agreements were only acceptable in some cases, and 10-20% deficiency was experienced. A boundary conforming grid made 0-2% errors at medium mesh, but was unphysical when refined and was not used. A huge problem was encountered, and not figured out: solutions were often worse instead of better when refining the grid. Possible explanations include numerical diffusion of the indicator variable , insufficient numerically dissipation in the damping zone, reflection energy into the system and poor boundary layer conformity, with maximum of 8 elements within the boundary

Protonic Transport Properties of Perovskite Heterostructures

Proton ceramic fuel cells based on an yttrium-doped barium zirconate electrolyte might pose as a viable option for future hydrogen applications. High resistances in the electrolyte however hampers the performance of the material. Therefore, a novel heterostructure engineering strategy is applied in order to investigate alternative solutions to reducing the resistances. This thesis aims to deepen our understanding of how heterostructures and their interfaces might affect the electrolyte resistances. The goal of the following approach is to circumvent proton trapping at acceptor dopant sites. A job-sharing model has been investigated where one phase “supplies” the protons while the other phase conducts them. The proton donor phase is acceptor doped and more acidic than the other phase, resulting in a net transfer of protons over to the conductive phase. The latter phase, free of trap sites and enriched in charge carriers, is then hypothesized to exhibit a conductivity increase. Modern computational methods allow for compositions to be investigated theoretically without having to perform tedious experiments. While experiments measure the actual effects of the system of interest, the results might be ambiguous as they often are a combination of several contributions. Theoretical computations on the other hand might give insight into trends, often on the atomistic scale, else impossible to separate from other effects experimentally. Combining the two methods, in depth knowledge and understanding of the system is acquirable. The model system, an alternating multi layered BaZr1-xYxO3/SrTi1-xScxO3 film was fabricated by pulsed laser deposition onto a (100) MgO substrate. The thin (60 nm) films were by X-ray diffraction confirmed to be grown epitaxially, made possible by a good lattice match between the substrate and the films. Impedance spectroscopy measurements of the BaZrO3/SrTi0.9Sc0.1O3 film showed a conductivity of 0.27 mS/cm, comparable to the conductivity of the reference BaZr0.9Y0.1O3 film (0.28 mS/cm). The activation energy of the heterostructure was measured to 0.45 eV, lower than for the reference BaZrO3 and BaZr0.9Y0.1O3 films and in the range of the proton migration activation energy. The SrTi0.9Sc0.1O3 had a larger activation energy of 0.64 eV, expected for oxide ion conduction mechanism. VII When going to dry from humid atmosphere for the BaZr1-xYxO3 containing films was a decrease in conductivity of 55 % to 65 %, attributed to a decrease in charge carrier (proton) concentrations which was further confirmed by a hydrogen isotope exchange. A slope of 0.143 was observed in the Arrhenius plot of the SrTi0.9Sc0.1O3 film, indicating that ionic defects dominate concentration-wise whilst minority holes contribute significantly to the conductivity in the measured pO2 range. First principles calculations of a BaZr0.984Y0.016O3H0.016 4 by 4 supercell showed the energy difference a at set of Y-H + distances. The trapping energy of the protons was calculated as a function of in-plane strain and was found to increase with more negative (compressive) strain. Additionally, strain in general decreases the long-range mobility of protons in the yttrium dopants because of an energy barrier, larger than or equal to the trapping energy. Removing -0.5 % of strain was found to result in an activation energy decrease, increasing the conductivity by a factor of two. The calculated trapping energy change for different levels of strain agree well with experimental activation energies from literature [1]. Comparisons of measurements between reference films and the BaZrO3/SrTi0.9Sc0.1O3 heterostructure supports the job-sharing model. By assuming that the space charge region of the BaZrO3 and SrTi0.9Sc0.1O3 does not affect the conductivity of the latter, a conductivity increase of a factor of 14 was calculated for the BaZrO3 layer of the heterostructure compared to the reference BaZrO3 film

The Jurassic of Kuhn Ø, North-East Greenland

The Middle–Upper Jurassic succession of Kuhn Ø, North-East Greenland accumulated in a major half-graben and is an excellent analogue for the subsurface of the mid-Norwegian shelf. On Kuhn Ø, peneplaned crystalline basement was incised by a drainage system during a major base-level lowstand, probably in late Early or early Middle Jurassic times. It was filled with fluvial conglomerates of the newly defined Middle Jurassic Bastians Dal Formation during subsequent base-level rise. As sea level continued to rise, precursor-peat of the coals of the Muslingebjerg Formation formed in swamps which covered the conglomerates and filled the remaining space of the incised valley system. The valley and interfluve areas were flooded in Late Bathonian – Callovian times and tidally-dominated, shallow marine sandstones of the Pelion Formation were deposited on top of the valley fill and over the adjacent basement peneplain. These sandstones are overlain by the newly defined shallow marine Oxfordian Payer Dal Formation which is subdivided into a lower unit and an upper unit, separated by a major drowning surface. The Payer Dal Formation sands were flooded in the Late Jurassic and organic-rich, offshore mudstones of the Bernbjerg Formation were deposited. The Jurassic succession of Kuhn Ø can thus be subdivided into large-scale sedimentary units separated by major drowning surfaces. They are of regional extent, and in combination with biostratigraphic and 87Sr/86Sr isotope data they allow the correlation of the sedimentary units on Kuhn Ø with more offshore deposits to the south in Wollaston Forland and more landwards successions to the north in Hochstetter Forland. Petrographically, the trough cross-bedded sandstones of the Pelion Formation and the lower unit of the Payer Dal Formation include both calcite-cemented and poorly cemented quartz sandstones. The calcite cement was derived from dissolution of abundant calcareous fossils and forms concretionary horizons. The upper unit of the Payer Dal Formation mainly consists of weaklycemented quartz sandstones with porosities around 30%. The sandstones of the Pelion and Payer Dal Formations on Kuhn Ø are petrographically very similar to Jurassic sandstones from the mid- Norwegian shelf and the Barents Sea with regard to original mineralogical composition, sorting and grain size. The Bernbjerg Formation mudstones are comparable to the Upper Jurassic source rock of the mid-Norwegian shelf and the Barents Sea, but have lower hydrogen index (HI) values due to terrigenous input in a relatively proximal setting. Coals of the Muslingebjerg Formation have significant source rock potential with measured HI values up to 700, kerogen types II–III and total organic carbon (TOC) values above 50%