Protocadherin-19 Expression and Function in Vertebrate Brain Review

For this project, a systematic review will be conducted on published studies on protocadherin-19 expression and function in vertebrate central nervous system development in the last 10 years. Protocadherin-19 (pcdh19) is a member of the cadherin superfamily. Cadherins are calcium-dependent cell adhesion molecules show to play important roles in vertebrate tissue development including the formation of the central nervous system. Understanding molecular and cellular mechanisms underlying the function of pcdh19 will help aid in understanding disease(s) caused by malfunction of this molecule, and lead to potential strategies for treatment. Data will be collected via online search of databases. The project is aimed to be completed by April 2021

Dynamical perturbations around an extreme mass ratio inspiral near resonance

Extreme mass ratio inspirals (EMRIs) -- systems with a compact object orbiting a much more massive (e.g., galactic center) black hole -- are of interest both as a new probe of the environments of galactic nuclei, and their waveforms are a precision test of the Kerr metric. This work focuses on the effects of an external perturbation due to a third body around an EMRI system. This perturbation will affect the orbit most significantly when the inner body crosses a resonance with the outer body, and result in a change of the conserved quantities (energy, angular momentum, and Carter constant) or equivalently of the actions, which results in a subsequent phase shift of the waveform that builds up over time. We present a general method for calculating the changes in action during a resonance crossing, valid for generic orbits in the Kerr spacetime. We show that these changes are related to the gravitational waveforms emitted by the two bodies (quantified by the amplitudes of the Weyl scalar $\psi_4$ at the horizon and at $\infty$) at the frequency corresponding to the resonance. This allows us to compute changes in the action variables for each body, without directly computing the explicit metric perturbations, and therefore we can carry out the computation by calling an existing black hole perturbation theory code. We show that our calculation can probe resonant interactions in both the static and dynamical limit. We plan to use this technique for future investigations of third-body effects in EMRIs and their potential impact on waveforms for LISA.Comment: 19 pages, 5 figures, 1 table, to be submitted to PR

Effect of dust in circumgalactic haloes on the cosmic shear power spectrum

Weak gravitational lensing is a powerful statistical tool for probing the growth of cosmic structure and measuring cosmological parameters. However, as shown by studies such as M\'enard et al. (2010), dust in the circumgalactic region of haloes dims and reddens background sources. In a weak lensing analysis, this selects against sources behind overdense regions; since there is more structure in overdense regions, we will underestimate the amplitude of density perturbations $\sigma_8$ if we do not correct for the effects of circumgalactic dust. To model the dust distribution we employ the halo model. Assuming a fiducial dust mass profile based on measurements from M\'enard et al. (2010), we compute the ratio $Z$ of the systematic error to the statistical error for a survey similar to the Nancy Grace Roman Space Telescope reference survey (2000 deg$^2$ area, single-filter effective source density 30 galaxies arcmin$^{-2}$). For a waveband centered at $1580$ nm ($H$-band), we find that $Z_{H} = 0.37$. For a similar survey with waveband centered at $620$ nm ($r$-band), we also computed $Z_{r} = 2.8$. Within our fiducial dust model, since $Z_{r} > 1$, the systematic effect of dust will be significant on weak lensing image surveys. We also computed the dust bias on the amplitude of the power spectrum, $\sigma_{8}$, and found it to be for each waveband $\Delta \sigma_8/\sigma_8 = -3.1\times 10^{-4}$ ($H$ band) or $-2.2\times 10^{-3}$ ($r$ band) if all other parameters are held fixed (the forecast Roman statistical-only error $\sigma(\sigma_8)/\sigma_8$ is $9\times 10^{-4}$).Comment: 17 pages, 8 figure

Determinants of Grain Postharvest Storage Technology Choices in Malawi

The study was conducted to determine factors influencing farmers’ choice of grain postharvest storage technologies. The study utilises IHS-3 data conducted by the National Statistics Office (NSO) in Malawi from March 2010 to March 2011. A stratified two-stage sample design was used for IHS-3.The multinomial logit model was used to analyse the factors. The results from the multinomial logit model revealed that farm size, education, production and marital status had an influence in choosing the grain storage technologies. The results further revealed that farm size and education were highly significant (p<0.001) in influencing the choice of grain storage technologies. The study, recommends that stakeholders should ensure that farmers have access to farm land to enhance production and access to education to change farmers’ perception on grain storage technologies to reduce grain loss thereby improving food security. Keywords: Multinomial Logit, Postharvest Storage Technology, Malaw

U.S Audiences' Perceptions of Covid-19 and Conservative News Frames

During the early stages of the COVID-19 pandemic, U.S. conservative news downplayed the threat of the virus. Perceived risks of COVID-19 are an important factor in influencing citizens' willingness to comply with risk prevention measures. An online survey (N=269) of U.S. residents was conducted March 30 - April 1, 2020. We found that those who used partisan conservative news sources as their primary source of information about the virus were significantly less likely to view it as a threat, compared to those who cited Far Left, Center Left, and Center Right news sources. Politically conservative Far Right news audiences reported significantly lower estimates of their own COVID-19 risk, as well as that of their age group peers, the average person in the U.S., and the average senior citizen in the U.S

Development of a decision support system for sustainable and resilience evaluation of urban underground space physical infrastructure

The research described in this thesis proposes a new,novel evaluation ‘framework’ and accompanying operational ‘model’, the ‘SUURE’ (Sustainable Underground Use Resilience Evaluation) ‘framework’, which adopts a socio-ecological systems (SES) approach to evaluation, combining sustainability science and resilience theory, at the same time incorporating a range of interdisciplinary tools and methods to achieve this. It purposes at its core to aid in sustainability evaluation of urban underground space, by evaluating the process to the outcome of sustainable solutions i.e. the capacity to adapt to change in different steady states. In consequence, a fundamentally different approach to planning that utilises future socio-ecological scenarios (NSP, PR, MF and FW) is incorporated in the ‘framework’ as a means of evaluating through its operational ‘model’, the sensitivity of investment decisions made today in the name of sustainability i.e. will the proposed engineering sustainability solution continue to deliver its intended function into the future, whatever that may be. The SUURE operational ‘model’ was employed as a proof of concept to the case study area of Birmingham Eastside, evaluating the potential use of multi-utility tunnels (MUT) in Eastside as a means of engendering sustainable and resilient use of urban underground space, through sustainable utility placement, both now and into the future. The flush-fitting MUT was found to be having the highest overall baseline (present-day) performance resilience index ratio at mean of 0.739, the shallow MUT second at 0.656, and the deep MUT last at 0.212. With regard to the evaluation of continued MUT functional performance into the future (whatever that may be), all three MUT options, if implemented today in the name of sustainability, would continue to deliver and retain their core functional performance, the deep MUT showing the most significant increase across all evaluation clusters (social, economic, physical, bio-physical and location aspects)

Forest structure, species diversity and spatial patterns of trees in monodominant and mixed stands in the Ituri Forest, Democratic Republic of Congo

Two rectangular 10-ha plots (200 x 500 m) were established in each of the two main forest types of the Ituri Forest, Democratic Republic of Congo (formerly Zaire). The description of stand structure and species diversity, the comparison of the two forest types, and the evaluation of the effects of canopy dominance on species richness were the main goals of the study. All shrubs and trees >1 cm dbh, and lianas >2 cm dbh were measured, tagged, mapped to the nearest half-meter, and identified. Stem density, basal area, species richness and spatial dispersion of species were determined. Statistical comparisons were performed using analysis of variance and the chi-square test. The density of trees >1 cm dbh was higher in mixed forest (8112 stems ha-1) than in monodominant forest (6844 stems ha-1). Density of stems >10 cm dbh was 438 ha-1 and 358 ha-1 in mixed and monodominant stands, respectively. Monodominant stands, with 98 stems >30 cm dbh ha-1, had more large trees than mixed stands (77 stems ha-1). Basal area was 37.7 m2 ha-1 and 32.6 m2 ha-1 for trees >1 cm dbh and >10 cm dbh in monodominant forest, and 33.2 m2 ha-1 and 26.2 m2 ha-1 in mixed forest, respectively. Mean number of species per hectare was 178, 56, and 14 at 1 cm dbh, 10 cm dbh and 30 cm dbh, respectively, in monodominant forest; in the same order, mean species richness per hectare was 170,68 and 27 in mixed forest. The density of Gilbertiodendron dewevrei, the dominant tree species of the monodominant stands, had a strong negative correlation with the species richness of trees >30 cm dbh. The vast majority of species exhibited significant clumping at all scales of analysis. No species had a significant regular dispersion pattern in the 10-ha plots. Small trees were more clumped than large trees and rare species were more clumped than more common species. Compared to many other tropical moist forests, the Ituri Forest was less diverse