Extent and Causes of Chesapeake Bay Warming

Coastal environments such as the Chesapeake Bay have long been impacted by eutrophication stressors resulting from human activities, and these impacts are now being compounded by global warming trends. However, there are few studies documenting long-term estuarine temperature change and the relative contributions of rivers, the atmosphere, and the ocean. In this study, Chesapeake Bay warming, since 1985, is quantified using a combination of cruise observations and model outputs, and the relative contributions to that warming are estimated via numerical sensitivity experiments with a watershed–estuarine modeling system. Throughout the Bay’s main stem, similar warming rates are found at the surface and bottom between the late 1980s and late 2010s (0.02 +/- 0.02C/year, mean +/- 1 standard error), with elevated summer rates (0.04 +/- 0.01C/year) and lower rates of winter warming (0.01 +/- 0.01C/year). Most (~85%) of this estuarine warming is driven by atmospheric effects. The secondary influence of ocean warming increases with proximity to the Bay mouth, where it accounts for more than half of summer warming in bottom waters. Sea level rise has slightly reduced summer warming, and the influence of riverine warming has been limited to the heads of tidal tributaries. Future rates of warming in Chesapeake Bay will depend not only on global atmospheric trends, but also on regional circulation patterns in mid-Atlantic waters, which are currently warming faster than the atmosphere. Supporting model data available at: https://doi.org/10.25773/c774-a36

Temporal expectations in the context of spatial expectations and stimulus competition

With this thesis, I investigated the effects of combined temporal and spatial expectations. In addition, I examined temporal expectations in the context of spatially and temporally competing distractors. In a parallel line of research, I studied the effects of aging on these functions. In Chapter 1, I introduce the subject of temporal expectations, review how they interact with other top-down biases, and argue why they should be investigated in the context of distraction. I also review theories of cognitive aging and motivate the investigation of age-related changes in the context of the main subjects of this thesis. In Chapter 2, I show that both behavioural performance and neural markers of pre-target processing can be modulated flexibly and beneficially by combined temporal and spatial expectations. I also show that neural markers of expectation seem to have behavioural relevance, and that temporal and spatial expectations can interact both neurally and behaviourally, when lateralised effects are investigated. I further demonstrate that aging compromises lateralised effects of spatio-temporal expectations. In Chapter 3, I show that perceptual effects of temporal expectations on stimulus competition depend on the stimulus context. Temporal expectations act independently of competition when stimuli are presented in different hemifields but can impair performance with intrahemifield competition. I further show that aging can spare the ability to suppress irrelevant information, and that older adults benefit from temporal expectations. In Chapter 4, I explore the effects of temporal expectations for a target stimulus when stimuli compete over time. I show that target-related behavioural performance can be increased, and pre-target distractor representations relatively decreased. In Chapter 5, I draw commonalities and differences across experimental Chapters 2-4, discussing temporal expectations in the context of isolated and competing stimuli, the relevance of lateralised effects of temporal expectations, age-related findings, and future questions and directions for research

An Examination of KCNE1 Mutations and Common Variants in Chronic Tinnitus

Chronic tinnitus is a highly prevalent and often incapacitating condition frequently associated with sensorineural hearing loss. While its etiology remains incompletely understood there is a growing awareness of genetic factors that predispose to, or aggravate chronic tinnitus. Candidate genes for the disorder include KCNE1, a potassium channel subunit gene that has been implicated in maturation defects of central vestibular neurons, in Menière's disease, and in noise-induced hearing loss. 201 Caucasian outpatients with a diagnosis of chronic tinnitus were systematically screened for mutations in the KCNE1 open reading frame and in the adjacent sequence by direct sequencing. Allele frequencies were determined for 46 known variants, plus two novel KCNE1 mutations. These comprised one missense substitution (V47I) in the highly conserved region encoding the KCNE1 transmembrane domain, and one rare variant in the gene's 3'UTR. When genotypes were grouped assuming dominance of the minor alleles, no significant genotype or compound genotype effects were observed on tinnitus severity. The newly identified V47I substitution argues in favor of an enlarged spectrum of mutations in hearing disorders. However, with regard to allele frequencies in healthy control populations from earlier studies, more common KCNE1 variants are unlikely to play a major role in chronic tinnitus. Further investigations are invited to address variation in additional channel subunits as possible risk factors in tinnitus

Functional connectivity between interoceptive brain regions is associated with distinct health-related domains: A population-based neuroimaging study.

Funder: Aarhus Universitets Forskningsfond; Id: http://dx.doi.org/10.13039/501100002739Funder: Health Data Research UK; Id: http://dx.doi.org/10.13039/501100023699Funder: Jabbs Foundation; Id: http://dx.doi.org/10.13039/501100016132Funder: National Institute of Health Research Biomedical Research CentreInteroception is the sensation, perception, and integration of signals from within the body. It has been associated with a broad range of physiological and psychological processes. Further, interoceptive variables are related to specific regions and networks in the human brain. However, it is not clear whether or how these networks relate empirically to different domains of physiological and psychological health at the population level. We analysed a data set of 19,020 individuals (10,055 females, 8965 males; mean age: 63 years, age range: 45-81 years), who have participated in the UK Biobank Study, a very large-scale prospective epidemiological health study. Using canonical correlation analysis (CCA), allowing for the examination of associations between two sets of variables, we related the functional connectome of brain regions implicated in interoception to a selection of nonimaging health and lifestyle related phenotypes, exploring their relationship within modes of population co-variation. In one integrated and data driven analysis, we obtained four statistically significant modes. Modes could be categorised into domains of arousal and affect and cardiovascular health, respiratory health, body mass, and subjective health (all p < .0001) and were meaningfully associated with distinct neural circuits. Circuits represent specific neural "fingerprints" of functional domains and set the scope for future studies on the neurobiology of interoceptive involvement in different lifestyle and health-related phenotypes. Therefore, our research contributes to the conceptualisation of interoception and may lead to a better understanding of co-morbid conditions in the light of shared interoceptive structures