Simulating eutrophication effects in Puget Sound using qualitative network models

Ecosystems are complex, dynamic networks of interacting physical, chemical, biological and social components. A stressor such as eutrophication thus can cause responses throughout the system via direct and indirect pathways and feedbacks. Ecosystem models are typically designed to account for as many critical components, functions and pathways as possible in order to reasonably simulate how a system may respond to a stressor; however, many aspects of ecosystem structure and function are poorly studied and too data-poor to represent in a quantitative, mechanistic model. Qualitative network models (QNMs) assume comparably simple (i.e., positive or negative) relationships between interacting components, and allow users to quickly assess potential impacts of stressors or management actions on both data-rich and data-poor aspects of a system. Here, we adapt a previously published QNM of Puget Sound to assess how eutrophication at different scales of space, time and system complexity might affect key species at all trophic levels as well as ecosystem services and human wellbeing. The outcomes of QNM simulations can be compared to other types of models for support and validation, and should be regarded as hypotheses that guide future quantitative studies and decision making in Puget Sound

Who is pre-disposed to insomnia? A psychobiological investigation

It has been hypothesised that a trait-like vulnerability to sleep disruption exists. This has been demonstrated in response to physiological stressors such as caffeine and phase advance. From this work the Ford Insomnia Responsivity to Stress (FIRST) questionnaire was designed, which aims to specify those who are vulnerable to stress related sleep disruption. Further to this, neuroticism and emotion focused coping have been shown to characterise the insomnia population, and suggested that these constitute risk factors for the development of an insomnia syndrome. However, there has been very little work which aims to define an at-risk population and none which aims to characterise this population from both a physiological and psychological perspective. The aim of this thesis is to define the vulnerable population with regards to psychology and psychobiology. . It was hypothesised that the vulnerable group would show greater stress reactivity, physiologically, higher levels of neuroticism relative to the resilient group, lower levels of conscientiousness and a greater inclination toward rumination and worry. Over three studies measures of sleep, personality, stress perception and coping styles amongst others were taken as well as measuring, separately, 3 indices of physiological stress response: Cortisol output: Salivary free cortisol was taken whilst a sample of good sleepers completed the Trier Social Stress Test (TSST) (n=32). Results indicate that the vulnerable group show significantly greater levels of cortisol at base line (p<0.05).This was mediated by conscientiousness (β=0.39). They were also higher in negative affect, rumination, stress and worry (p<0.05).The vulnerable group also showed an increase in insomnia symptoms in response to real life stress. This was also related to conscientiousness (r= 0.55, p<0.05) Cardiovascular response: Heart Rate (HR) and Cardiac Vagal Tone (CVT) were measured while participants (n=31) completed a relaxation (baseline) and stressful task. There was found to be a main effect of group on HR response to the stress task relative to baseline, but this did not maintain when psychological variables of interest were entered (n=31) into the model. Conscientiousness was related to lower CVT change, interpreted as lower CVT flexibility. Psychologically, the vulnerable group were again found to score higher on neuroticism, perceived stress and rumination relative to the resilient group (p<0.05). Brain activation: fMRI data was collected whilst participants completed a stroop task, in which a siren indicated an increase in task difficulty (stress cue) (n=24). It was found that the vulnerable group showed significantly less activation bilaterally in the inferior parietal lobule (IPL) (p<0.001). In the left IPL activation was mediated by neuroticism (β=0.607).There was also significantly greater activation in the left postcentral gyrus (PG) (p<0.001), compared to the resilient group. This was mediated by FIRST score (β=-0.61). Again, the vulnerable group scored higher on measures of neuroticism and lower on conscientiousness (p<0.05). Psychometric information gathered across the 3 studies was collapsed into one dataset (n=84). ANOVA revealed that the vulnerable group had significantly higher scores on measures of neuroticism, perceived stress, state stress, depressive feelings, depressive thinking, brooding, worry, emotion focused and problem focused coping and significantly lower scores on conscientiousness and extroversion (p<0.05). Results indicate that the vulnerable group are higher on neuroticism across all 3 studies, and score higher on rumination and stress questionnaires in 2 of the studies. Physiological data suggests that the vulnerable group are more sensitive to stress anticipation, as opposed to showing greater reactivity to stress. It is concluded that neuroticism is a risk factor for developing insomnia and that the vulnerable population show greater physiological responses whilst anticipating stress, a phenomena which represents the interaction between personality, rumination and the physiology of the stress system

Modelling Ecosystem Processes Acting On Upper Trophic Level Managed Species in the Salish Sea – Lessons Learned and Future Goals

Ecosystem models provide a means to examine how large-scale drivers and food web interactions can influence change in marine species. Coho and Chinook salmon are iconic species in the Salish Sea and have been significant components of ecosystem models developed for its sub-basins. We present results from models of three regions in the Salish Sea: the Strait of Georgia, the Central Basin of Puget Sound, and the Southern Basin of Puget Sound. Each of these models provides reasonable simulations of how ecosystem-level mechanisms can influence changes in target managed species. While there is some overlap in these models’ ability to explore changes in mammals and fished species, regional differences remain that make it difficult to integrate knowledge at the scale of the Salish Sea as a whole. For example, the Strait of Georgia and Puget Sound models all suggest that bottom-up type dynamics have influenced the dynamics of many species. Significant contrast, however, can be seen in the dominance of the Central basin of Puget Sound by ratfish, approximately a third of all fish biomass whereas, in the Strait of Georgia, Pacific herring and small pelagic species account for a third of all fish biomass. Understanding these similarities and differences will help researchers explain why significant species like Coho and Chinook salmon can exhibit quite different population dynamics in regions of the Salish Sea. As part of an integrated project spearheaded by the Pacific Salmon Foundation and Long Live the Kings, we hope to increase the overlap in both species and mechanisms modelled in future iterations of these modelling efforts

Overlapping functionality of the Pht proteins in zinc homeostasis of streptococcus pneumoniae

Streptococcus pneumoniae is a globally significant pathogen that causes a range of diseases, including pneumonia, sepsis, meningitis, and otitis media. Its ability to cause disease depends upon the acquisition of nutrients from its environment, including transition metal ions such as zinc. The pneumococcus employs a number of surface proteins to achieve this, among which are four highly similar polyhistidine triad (Pht) proteins. It has previously been established that these proteins collectively aid in the delivery of zinc to the ABC transporter substrate-binding protein AdcAII. Here we have investigated the contribution of each individual Pht protein to pneumococcal zinc homeostasis by analyzing mutant strains expressing only one of the four pht genes. Under conditions of low zinc availability, each of these mutants showed superior growth and zinc accumulation profiles relative to a mutant strain lacking all four genes, indicating that any of the four Pht proteins are able to facilitate delivery of zinc to AdcAII. However, optimal growth and zinc accumulation in vitro and pneumococcal survival and proliferation in vivo required production of all four Pht proteins, indicating that, despite their overlapping functionality, the proteins are not dispensable without incurring a fitness cost. We also show that surface-attached forms of the Pht proteins are required for zinc recruitment and that they do not contribute to defense against extracellular zinc stress

The first histidine triad motif of phtd is critical for zinc homeostasis in Streptococcus pneumoniae

Streptococcus pneumoniae is the world's foremost human pathogen. Acquisition of the first row transition metal ion zinc is essential for pneumococcal colonization and disease. Zinc is acquired via the ATP-binding cassette transporter AdcCB and two zinc-binding proteins, AdcA and AdcAII. We have previously shown that AdcAII is reliant upon the polyhistidine triad (Pht) proteins to aid in zinc recruitment. Pht proteins generally contain five histidine (His) triad motifs that are believed to facilitate zinc binding and therefore play a significant role in pneumococcal metal ion homeostasis. However, the importance and potential redundancy of these motifs have not been addressed. We examined the effects of mutating each of the five His triad motifs of PhtD. The combination of in vitro growth assays, active zinc uptake, and PhtD expression studies show that the His triad closest to the protein's amino terminus is the most important for zinc acquisition. Intriguingly, in vivo competitive infection studies investigating the amino- and carboxyl-terminal His triad mutants indicate that the motifs have similar importance in colonization. Collectively, our new insights into the contributions of the individual His triad motifs of PhtD, and by extension the other Pht proteins, highlight the crucial role of the first His triad site in zinc acquisition. This study also suggests that the Pht proteins likely play a role beyond zinc acquisition in pneumococcal virulence

Participation of adults with learning disabilities in the 2015 United Kingdom General Election

Purpose People with learning disabilities may experience discrimination which prevents them from exercising choice and control over their right to participate in democratic processes. Design/methodology/approach Taking data collected by social workers during a campaign from the 2015 UK General Election, this paper analyses the variables associated with higher rates of democratic participation by people with learning disabilities. Findings The present authors undertook secondary analysis on data collected by social workers supporting adults with learning disabilities who were living in community housing units. 1,019 people with learning disabilities who were living in 124 community housing units in one English county gave consent to participate. 84% were registered to vote and 26% cast a vote on polling day. People were significantly more likely to cast a vote if they lived in a housing unit where they understood their rights (Waldx^2=4.896, p=0.027). Practical implications Our analyses are consistent with the hypothesis that supporting people with learning disabilities to understand their right to participate in elections increases the likelihood they will cast a vote on a polling day. There are practical implications from this finding for commissioning practices, support planning, and education of health and social care practitioners. Originality/value This is the first study of this size which examines data from people with learning disabilities on their experience of democratic participation and the role of social work.This is the first study of this size which examines the data from learning disabled people on their experience of democratic participation and the role of social work

Adding Value to JWST Spectra and Photometry: Stellar Population and Star Formation Properties of Spectroscopically Confirmed JADES and CEERS Galaxies at z>7z > 7

In this paper, we discuss measurements of the stellar population and star forming properties for 43 spectroscopically confirmed publicly available high-redshift $z > 7$ JWST galaxies in the JADES and CEERS observational programs. We carry out a thorough study investigating the relationship between spectroscopic features and photometrically derived ones, including from spectral energy distribution (SED) fitting of models, as well as morphological and structural properties. We find that the star formation rates (SFRs) measured from H$\beta$ line emission are higher than those estimated from Bayesian SED fitting and UV luminosity, with ratios SFR$_{H\beta}$/ SFR$_{UV}$ ranging from 2~13. This is a sign that the star formation history is consistently rising given the timescales of H$\beta$ vs UV star formation probes. In addition, we investigate how well equivalent widths (EWs) of H$\beta$ $\lambda$4861, [O III] $\lambda$4959, and [O III] $\lambda$5007 can be measured from photometry, finding that on average the EW derived from photometric excesses in filters is 30% smaller than the direct spectroscopic measurement. We also discover that a stack of the line emitting galaxies shows a distinct morphology after subtracting imaging that contains only the continuum. This gives us a first view of the line or ionized gas emission from $z > 7$ galaxies, demonstrating that this material has a similar distribution, statistically, as the continuum. We also compare the derived SFRs and stellar masses for both parametric and non-parametric star formation histories, where we find that 35% of our sample formed at least 30% of their stellar mass in recent (< 10 Myr) starburst events.Comment: 17 Pages, 13 Figures, 4 Tables, submitted to MNRA

Superconductivity in AuNiGe Ohmic contacts to a GaAs-based high mobility two-dimensional electron gas

To cool a high mobility two-dimensional electron gas (2DEG) at a GaAs-AlGaAs heterojunction to milliKelvin temperatures, we have fabricated low resistance Ohmic contacts based on alloys of Au, Ni, and Ge. The Ohmic contacts have a typical contact resistance of R C ≈ 0.8 ω at 4.2 K, which drops to 0.2 ω below 0.9 K. Scanning electron microscope images establish that the contacts have the same inhomogeneous microstructure that has been observed in previous studies. Measurements of the contact resistance R C, the four-terminal resistance along the top of a single contact, and the vertical resistance RV all show that there is a superconductor in the Ohmic contact, which can be turned completely normal with a magnetic field of 0.15 T. We briefly discuss how this superconductivity may be affecting the electrical transport measurements of 2DEGs, especially how it may hinder the cooling of electrons in a 2DEG below 0.1 K

On the observability and identification of Population III galaxies with JWST

We utilise theoretical models of Population III stellar+nebular spectra to investigate the prospects of observing and accurately identifying Population III galaxies with JWST using both deep imaging and spectroscopy. We investigate a series of different colour cuts, finding that a combination of NIRCam and MIRI photometry through the F444W-F560W, F560W-F770W colours offers the most robust identifier of potential $z=8$ Pop III candidates. We calculate that NIRCam will have to reach $\sim$28.5-30.0 AB mag depths (1-20 h), and MIRI F560W must reach $\sim$27.5-29.0 AB mag depths (10-100 h) to achieve $5\sigma$ continuum detections of $M_* = 10^6~\mathrm{M}_\odot$ Pop III galaxies at $z=8$. We also discuss the prospects of identifying Pop III candidates through slitless and NIRSpec spectroscopic surveys that target Ly$\alpha$, H$\beta$ and/or He II $\lambda 1640$. We find small differences in the H$\beta$ rest-frame equivalent width (EW) between Pop III and non-Pop III galaxies, rendering this diagnostic likely impractical. Instead, we find that the detection of high EW He II $\lambda 1640$ emission will serve as the definitive Pop III identifier, requiring (ultra-)deep integrations (10-250 h) with NIRSpec/G140M for $M_*=10^6~\mathrm{M}_\odot$ Pop III galaxies at $z=8$. However, MIRI F770W detections of Pop III galaxies will require substantial gravitational lensing ($\mu=10$) and/or fortuitous imaging of exceptionally massive ($M_* = 10^7~\mathrm{M}_\odot$) Pop III galaxies. Thus, NIRCam medium-band imaging surveys that can search for high EW He II $\lambda 1640$ emitters in photometry may perhaps be a viable alternative for finding Pop III candidates.Comment: 17 figures, 7 tables. Updated to match published version in MNRA