Anharmonic oscillator and double-well potential: approximating eigenfunctions

A simple uniform approximation of the logarithmic derivative of the ground state eigenfunction for both the quantum-mechanical anharmonic oscillator and the double-well potential given by $V= m^2 x^2+g x^4$ at arbitrary $g \geq 0$ for $m^2>0$ and $m^2<0$, respectively, is presented. It is shown that if this approximation is taken as unperturbed problem it leads to an extremely fast convergent perturbation theory.Comment: 14 pages, 3 figures, 2 table

Microbial Nitrate Dependent Fe²⁺ Oxidation: A Potential Early Mars Metabolism

This thesis experimentally investigates the proposition that aqueous environments with anoxic, reducing, circumneutral conditions, inorganic electron donors and oxidants such as nitrate may have allowed chemolithotrophic microbial metabolisms, such as nitrate-dependent Fe2+ oxidation (NDFO), to thrive on early Mars. The NDFO microorganisms, Acidovorax sp. strain BoFeN1, Paracoccus sp. strain KS1 and Pseudogulbenkiania sp. strain 2002, are demonstrated to grow lithoautotrophically with a Mars-relevant olivine Fe2+ source and in martian simulant media developed from in situ and meteorite geochemical data. Additionally, mixotrophic NDFO with Fe2+ and an organic co-substrate as electron donors, was shown to increase the extent of microbial growth, which gains importance in light of the confirmation of complex organics at the martian surface. Biomineralised microbial features were discovered after culture with olivine and the oxidation of Fe2+ was measured in heterotrophic cultures. Microfossils and Fe3+ compounds in reducing contexts provide targets for biosignature detection missions. In addition, this work presents findings on the biochemical mechanisms of NDFO, quantifying the relative contributions of the Nar respiratory nitrate reductase enzyme, putative ferroxidases and nitrite accumulation to Fe2+ oxidation during nitrate reduction. Gene knockout experiments revealed that Fe2+ oxidation in the heterotrophic Salmonella enterica Serovar Typhimurium strain SL1344 is largely driven by the production of reactive nitrite ions during Nar activity. Draft genome analysis of Acidovorax sp. strain BoFeN1 and Paracoccus sp. strain KS1 revealed potential mechanisms of electron acquisition during Fe2+ oxidation, underlining that multiple mechanisms of NDFO exist. The combined findings of this thesis support the plausibility of NDFO in the deep martian past and propose mechanisms by which evidence may be preserved in the geological record of that planet

Bayesian Variational Regularisation for Dark Matter Reconstruction with Uncertainty Quantification

Despite the great wealth of cosmological knowledge accumulated since the early 20th century, the nature of dark-matter, which accounts for ~85% of the matter content of the universe, remains illusive. Unfortunately, though dark-matter is scientifically interesting, with implications for our fundamental understanding of the Universe, it cannot be directly observed. Instead, dark-matter may be inferred from e.g. the optical distortion (lensing) of distant galaxies which, at linear order, manifests as a perturbation to the apparent magnitude (convergence) and ellipticity (shearing). Ensemble observations of the shear are collected and leveraged to construct estimates of the convergence, which can directly be related to the universal dark-matter distribution. Imminent stage IV surveys are forecast to accrue an unprecedented quantity of cosmological information; a discriminative partition of which is accessible through the convergence, and is disproportionately concentrated at high angular resolutions, where the echoes of cosmological evolution under gravity are most apparent. Capitalising on advances in probability concentration theory, this thesis merges the paradigms of Bayesian inference and optimisation to develop hybrid convergence inference techniques which are scalable, statistically principled, and operate over the Euclidean plane, celestial sphere, and 3-dimensional ball. Such techniques can quantify the plausibility of inferences at one-millionth the computational overhead of competing sampling methods. These Bayesian techniques are applied to the hotly debated Abell-520 merging cluster, concluding that observational catalogues contain insufficient information to determine the existence of dark-matter self-interactions. Further, these techniques were applied to all public lensing catalogues, recovering the then largest global dark-matter mass-map. The primary methodological contributions of this thesis depend only on posterior log-concavity, paving the way towards a, potentially revolutionary, complete hybridisation with artificial intelligence techniques. These next-generation techniques are the first to operate over the full 3-dimensional ball, laying the foundations for statistically principled universal dark-matter cartography, and the cosmological insights such advances may provide

Examining the Connections Between Time, Length, and Specificity Factors in Homework and Undergraduate Grade Outcomes

This study was conducted with students previously enrolled in a 200-level educational psychology course from the Fall 2018 and Fall 2019 semesters (N = 331, students per section ranged from 23 – 31). The purpose of this study was to examine the relationships between time, length, and specificity factors found in homework taken from Canvas on students’ homework, exam, and final course grades. The time and length factors taken from a graded homework assignments were used to examine homework scores while the mean values and standard deviation values for these factors taken from all of the homework assignments in a unit were used to examine exam scores. The standard deviation values were used as a measure of consistency among all submitted homework assignments. The specificity factor was created from all of the graded homework assignments and used to examine the final scores in the course. Several linear mixed models were used to individually examine the relationships between the time and length factors on students’ graded homework scores and unit exam scores. A linear regression was used to examine the relationship between the specificity factor and students’ final scores in the course. Homework scores were significantly related to exam scores. The results among the time factors yielded some significant relationships, but the significant relationships were not meaningful. The results for the length factors, however, were significant and meaningful. The results for the specificity factor were not significant. Among these factors examined, length factors appear to be the strongest contributor to students’ grades

Tracking the Short Term Planning (STP) Development Process

Part of the National Aeronautics and Space Administration?s mission is to pioneer the future in space exploration, scientific discovery and aeronautics research is enhanced by discovering new scientific tools to improve life on earth. Sequentially, to successfully explore the unknown, there has to be a planning process that organizes certain events in the right priority. Therefore, the planning support team has to continually improve their processes so the ISS Mission Operations can operate smoothly and effectively. The planning support team consists of people in the Long Range Planning area that develop timelines that includes International Partner?s Preliminary STP inputs all the way through to publishing of the Final STP. Planning is a crucial part of the NASA community when it comes to planning the astronaut?s daily schedule in great detail. The STP Process is in need of improvement, because of the various tasks that are required to be broken down in order to get the overall objective of developing a Final STP done correctly. Then a new project came along in order to store various data in a more efficient database. "The SharePoint site is a Web site that provides a central storage and collaboration space for documents, information, and ideas.

Burden of podoconiosis in poor rural communities in Guliso woreda, western Ethiopia

Background. Podoconiosis is an environmental lymphoedema affecting people living and working barefoot on irritant red clay soil. Podoconiosis is relatively well described in southern Ethiopia, but remains neglected in other parts of the Ethiopian highlands. This study aimed to assess the burden of podoconiosis in rural communities in western Ethiopia. Methodology/Principal Findings. A cross-sectional study was conducted in Gulliso woreda (district), west Ethiopia. A household survey in the 26 rural kebeles (villages) of this district was conducted to identify podoconiosis patients and to measure disease prevalence. A more detailed study was done in six randomly selected kebeles to describe clinical features of the disease, patients’ experiences of foot hygiene, and shoe wearing practice. 1,935 cases of podoconiosis were registered, giving a prevalence of 2.8%. The prevalence was higher in those aged 15 – 64 years (5.2%) and in females than males (prevalence ratio 2.6:1). 90.3% of patients were in the 15 – 64 year age group. In the detailed study, 335 cases were interviewed and their feet assessed. The majority of patients were farmers, uneducated, and poor. Two-third of patients developed the disease before the age of thirty. Almost all patients (97.0%) had experienced adenolymphangitis (ALA - red, hot legs, swollen and painful groin) at least once during the previous year. Patients experienced an average of 5.5 ALA episodes annually, each of average 4.4 days, thus 24 working days were lost annually. The incidence of ALA in podoconiosis patients was higher than that reported for filariasis in other countries. Shoe wearing was limited mainly due to financial problems. Conclusions. We have documented high podoconiosis prevalence, frequent adenolymphangitis and high disease-related morbidity in west Ethiopia. Interventions must be developed to prevent, treat and control podoconiosis, one of the core neglected tropical diseases in Ethiopia

Collapse of a molecular cloud core to stellar densities: the radiative impact of stellar core formation on the circumstellar disc

We present results from the first three-dimensional radiation hydrodynamical calculations to follow the collapse of a molecular cloud core beyond the formation of the stellar core. We find the energy released by the formation of the stellar core, within the optically-thick first hydrostatic core, is comparable to the binding energy of the disc-like first core. This heats the inner regions of the disc, drives a shock wave through the disc, dramatically decreases the accretion rate on to the stellar core, and launches a temporary bipolar outflow perpendicular to the rotation axis that travels in excess of 50 AU into the infalling envelope. This outburst may assist the young protostar in launching a conventional magnetic jet. Furthermore, if these events are cyclic, they may provide a mechanism for intense bursts of accretion separated by long periods of relatively quiescent accretion which can potentially solve both the protostellar luminosity problem and the apparent age spread of stars in young clusters. Such outbursts may also provide a formation mechanism for the chondrules found in meteorites, with the outflow transporting them to large distances in the circumstellar disc.Comment: Accepted by MNRAS Letters. 6 pages, 4 figures. Animations can be found at http://www.astro.ex.ac.uk/people/mbate/Animations/Stellar

Astrophysical Weighted Particle Magnetohydrodynamics

This paper presents applications of weighted meshless scheme for conservation laws to the Euler equations and the equations of ideal magnetohydrodynamics. The divergence constraint of the latter is maintained to the truncation error by a new meshless divergence cleaning procedure. The physics of the interaction between the particles is described by an one-dimensional Riemann problem in a moving frame. As a result, necessary diffusion which is required to treat dissipative processes is added automatically. As a result, our scheme has no free parameters that controls the physics of inter-particle interaction, with the exception of the number of the interacting neighbours which control the resolution and accuracy. The resulting equations have the form similar to SPH equations, and therefore existing SPH codes can be used to implement the weighed particle scheme. The scheme is validated in several hydrodynamic and MHD test cases. In particular, we demonstrate for the first time the ability of a meshless MHD scheme to model magneto-rotational instability in accretion disks.Comment: 27 pages, 24 figures, 1 column, submitted to MNRAS, hi-res version can be obtained at http://www.strw.leidenuniv.nl/~egaburov/wpmhd.pd

Design led innovation: shifting from smart follower to digital strategy leader in the Australian airport sector

This paper presents and discusses organisational barriers and opportunities arising from the dissemination of design led innovation within a leading Australian airport corporation. This research is part of a greater action research program which aims to integrate design as a strategic capability through design led innovation within Australian businesses. Findings reveal that there is an opportunity to employ the theoretical framework and tools of design led innovation in practice to build collaborative idea generation by involving customers and stakeholders within the proposal of new to world propositions. The iterative gathering of deep customer insights also provided an opportunity to leverage a greater understanding of stakeholders and customers in strengthening continuing business partnerships through co-design. Challenges to the design led approach include resistance to the exploratory nature of gathering deep customer insights, the testing of long held assumptions and market data, and the disruption of an organisational mindset geared toward risk aversion instilled within the aviation industry. The implication from these findings is that design led innovation can provide the critical platform to allow for a business to grow and sustain internal design capabilities necessary to challenge prevailing assumptions about how its business model operates to deliver value to customers and stakeholders alike. The platform of design led innovation also provides an avenue to support a cultural transformation towards anticipating future needs necessary for establishing a position of leadership within the broader economic environment