Renal function, revascularization and risk

Peer reviewedAuthor versio

Effects of multiple stressors on primary production in Lake Erie

An unnatural increase in primary production is the main driver of accelerated eutrophication, which causes negative impacts in aquatic systems around the world. Studying factors regulating primary production is therefore critical in systems such as Lake Erie, which experiences eutrophication and has been impacted by many stressors. In this thesis, I investigated factors regulating primary production in Lake Erie on both a long-term temporal scale (by comparing summer values from 1970 to 2014/15 in the western basin) and a spatial scale (by comparing nearshore and offshore sites among the three basins). Both studies suggested that multiple stressors, such as changes in nutrient loading, dreissenid grazing, and light penetration, are likely regulating primary production in Lake Erie. Dreissenid grazing and phosphorus loading reductions may have contributed to a long-term decrease in volumetric primary production in the western basin, as well as to similar volumetric primary production between near and offshore sites in all three basins. Meanwhile, a long-term increase in light penetration in the western basin resulted in no significant change in areal primary production since 1970. Increased light penetration in the eastern basin also resulted in no significant difference in areal primary production compared to the other basins, despite significantly lower volumetric primary production in the eastern basin. In the future, nutrient enrichment experiments and annual primary production measurements are needed. This study demonstrates the complexity of factors regulating primary production and the importance of studying these factors to understand drivers of eutrophication and food web dynamics in Lake Erie

Utility of B-type natriuretic peptide in predicting medium-term mortality in patients undergoing major non-cardiac surgery

We assessed the ability of pre-operative B-type natriuretic peptide (BNP) levels to predict medium-term mortality in patients undergoing major noncardiac surgery. During a median 654 days follow-up 33 patients from a total cohort of 204 patients (16%) died. The optimal cut-off in this cohort, determined using a receiver operating characteristic curve, was >35pg.mL-1. This was associated with a 3.47-fold increase in the hazard of death (p=0.001) and had a sensitivity of 70% and a specificity of 68% for this outcome. These findings extend recent work demonstrating that BNP levels obtained before major noncardiac surgery can be used to predict peri-operative morbidity, and indicate that they also forecast medium-term mortality.This work was supported by a grant from TENOVUS Scotland. The Health Services Research Unit is core-funded by the Chief Scientists Office of the Scottish Executive Health Department.Peer reviewedAuthor versio

Phylogenetic relationships of Indian caecilians (Amphibia: Gymnophiona) inferred from mitochondrial rRNA gene sequences

India has a diverse caecilian fauna, including representatives of three of the six currently recognized families, the Caeciliidae, Ichthyophiidae, the endemic Uraeotyphlidae, but previous molecular phylogenetic studies of caecilians have not included sequences for any Indian caecilians. Partial 12S and 16S mitochondrial gene sequences were obtained for a single representative of each of the caecilian families found in India and aligned against previously reported sequences for 13 caecilian species. The resulting alignment (16 taxa, 1200 sites, of which 288 cannot be aligned unambiguously) was analyzed using parsimony, maximum-likelihood, and distance methods. As judged by bootstrap proportions, decay indices, and leaf stabilities, well-supported relationships of the Indian caecilians are recovered from the alignment. The data (1) corroborate the hypothesis, based on morphology, that the Uraeotyphlidae and Ichthyophiidae are sister taxa, (2) recover a monophyletic Ichthyophiidae, including Indian and South East Asian representatives, and (3) place the Indian caeciliid Gegeneophis ramaswamii as the sister group of the caeciliid caecilians of the Seychelles. Rough estimates of divergence times suggest an origin of the Uraeotyphlidae and Ichthyophiidae while India was isolated from Laurasia and Africa and are most consistent with an Indian origin of these families and subsequent dispersal of ichthyophiids into South East Asia

Lesion Loci of Impaired Affective Prosody: A Systematic Review of Evidence from Stroke

Affective prosody, or the changes in rate, rhythm, pitch, and loudness that convey emotion, has long been implicated as a function of the right hemisphere (RH), yet there is a dearth of literature identifying the specific neural regions associated with its processing. The current systematic review aimed to evaluate the evidence on affective prosody localization in the RH. One hundred and ninety articles from 1970 to February 2020 investigating affective prosody comprehension and production in patients with focal brain damage were identified via database searches. Eleven articles met inclusion criteria, passed quality reviews, and were analyzed for affective prosody localization. Acute, subacute, and chronic lesions demonstrated similar profile characteristics. Localized right antero-superior (i.e., dorsal stream) regions contributed to affective prosody production impairments, whereas damage to more postero-lateral (i.e., ventral stream) regions resulted in affective prosody comprehension deficits. This review provides support that distinct RH regions are vital for affective prosody comprehension and production, aligning with literature reporting RH activation for affective prosody processing in healthy adults as well. The impact of study design on resulting interpretations is discussed

Preoperative neutrophil-lymphocyte ratio and outcome from coronary artery bypass grafting

Background: An elevated preoperative white blood cell count has been associated with a worse outcome after coronary artery bypass grafting (CABG). Leukocyte subtypes, and particularly the neutrophil-lymphocyte (N/L) ratio, may however, convey superior prognostic information. We hypothesized that the N/L ratio would predict the outcome of patients undergoing surgical revascularization. Methods: Baseline clinical details were obtained prospectively in 1938 patients undergoing CABG. The differential leukocyte was measured before surgery, and patients were followed-up 3.6 years later. The primary end point was all-cause mortality. Results: The preoperative N/L ratio was a powerful univariable predictor of mortality (hazard ratio [HR] 1.13 per unit, P 3.36). Conclusion: An elevated N/L ratio is associated with a poorer survival after CABG. This prognostic utility is independent of other recognized risk factors.Peer reviewedAuthor versio

Orphanhood and caregiver loss among children based on new global excess COVID-19 death estimates

The availability of new excess mortality data enables us to update global minimum estimates of COVID-19 orphanhood and caregiver death among children.1-4 Consequences for children can be devastating, including institutionalization, abuse, traumatic grief, mental health problems, adolescent pregnancy, poor educational outcomes, and chronic and infectious diseases.4,5 Global totals and country comparisons were previously hampered by inconsistencies in COVID-19 testing and incomplete death reporting. The new orphanhood estimates derived here based on excess deaths provide a comprehensive measure of COVID-19’s long-term impact on orphanhood and caregiver loss

Bringing Forecasting Into the Future: Using Google to Predict Visitation in U.S. National Parks

In recent years, visitation to U.S. National Parks has been increasing, with the majority of this increase occurring in a subset of parks. As a result, managers in these parks must respond quickly to increasing visitor-related challenges. Improved visitation forecasting would allow managers to more proactively plan for such increases. In this study, we leverage internet search data that is freely available through Google Trends to create a forecasting model. We compare this Google Trends model to a traditional autoregressive forecasting model. Overall, our Google Trends model accurately predicted 97% of the total visitation variation to all parks one year in advance from 2013 to 2017 and outperformed the autoregressive model by all metrics. While our Google Trends model performs better overall, this was not the case for each park unit individually; the accuracy of this model varied significantly from park to park. We hypothesized that park attributes related to trip planning would correlate with the accuracy of our Google Trends model, but none of the variables tested produced overly compelling results. Future research can continue exploring the utility of Google Trends to forecast visitor use in protected areas, or use methods demonstrated in this paper to explore alternative data sources to improve visitation forecasting in U.S. National Parks