The Vulnerability of Northern High-Latitude Ecosystems to Climate and Disturbance-Induced Change

University of Minnesota Ph.D. dissertation.June 2018. Major: Natural Resources Science and Management. Advisor: Joseph Knight. 1 computer file (PDF); xiii, 161 pages.Arctic and boreal regions have experienced unprecedented changes in recent decades as the result of climate change. Increasing air temperatures have led to widespread warming and degradation of permafrost, significant shifts in vegetation composition and productivity, and increases in disturbance frequency and extent that can have profound impacts on ecosystems and human populations across the globe. Despite a legacy of studies describing the heightened sensitivity of arctic and boreal ecosystems to change, there has not been a comprehensive assessment of historical and projected trends in landscape properties, disturbances, and drivers of change throughout all of Alaska. Such an assessment is immensely challenging because of spatially-heterogeneous dynamics and interactions among numerous factors that influence ecosystems throughout the State. Consequently, additional research is needed to better characterize permafrost-affected landscapes and their potential response to further perturbations. This dissertation presents important improvements in the mechanistic understanding and characterization capabilities of changing permafrost landscapes by combining field measurements, time series analyses, climate reanalysis data, and remote sensing into an integrated modeling framework. The primary goal is to improve understanding of how and why globally significant permafrost landscapes are changing by means of: (1) Characterizing climate, permafrost, disturbance, and vegetation dynamics that exert strong controls on energy, water, and biogeochemical cycling; (2) Quantifying underlying drivers of change related to contemporary trends in land and water surfaces observed by remote sensing; and; (3) Providing novel approaches and baseline information to fill critical observational gaps identified by the remote sensing community and permafrost and ecosystem scientists. This research supports the science priorities of federal agencies (e.g. United States Geological Survey, National Aeronautics and Space Administration) and techniques and results are highly relevant to climatic, hydrologic, ecologic, topographic, and cryospheric studies. This research provides critically needed information on the temporal and regional distribution of landscape properties and conditions, which is instrumental in determining the vulnerability and resilience of northern high-latitudes regions to climate and disturbance-induced change, and benefits both the research community and the policy community in the management of Arctic and boreal landscapes.Pastick, Neal. (2018). The Vulnerability of Northern High-Latitude Ecosystems to Climate and Disturbance-Induced Change. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/200279

Pregnancy-Related Tuberculous Meningitis and Immune Reconstitution Inflammatory Syndrome: A Case Series and Systematic Review

Background: Tuberculosis is a leading cause of death among women of reproductive age. However, tuberculous meningitis, the most severe form of extrapulmonary tuberculosis, is rarely discussed in pregnancy despite this being a unique period of immune modulation that may predispose women to active disease. Methods: We identified and described cases of tuberculous meningitis among pregnant or postpartum women screened during meningitis clinical trials in Uganda from 2018 to 2022. We conducted a systematic literature review via PubMed/Medline and Embase for all English-language publications from 1970 to 10 July 2022, to identify additional cases. Results: We identified 8 cases of pregnancy-related tuberculous meningitis in Ugandan women living with human immunodeficiency virus (HIV) and 40 additional cases via systematic literature review (none HIV-positive). Of all combined cases, 50% (24/48) were diagnosed postpartum; 50% (24/48) had initial onset during pregnancy, of which 38% (9/24) had worsening of symptoms or disease relapse following pregnancy cessation. Diagnosis was missed or delayed in 33% (16/48) of cases. For those with known outcomes, maternal mortality was 23% (11/48) and fetal/neonatal mortality was 30% (13/44). Of maternal survivors, 30% (11/37) had residual neurologic deficits. Conclusions: The true incidence of tuberculous meningitis in pregnancy or the postpartum period is unclear but likely underappreciated. To date, nearly all published cases have occurred in HIV-negative or otherwise immunocompetent women. Given the well-described physiological immunosuppression during pregnancy and subsequent reconstitution postpartum, physicians must be aware of tuberculous meningitis and pregnancy-related immune reconstitution inflammatory syndrome, especially in countries with a high burden of tuberculosis and in women living with HIV

EVALUATION OF ARTHROGRYPOTIC FOOT TREATMENT: MINIMUM 10 YEARS FOLLOW-UP

ABSTRACT Objective: To evaluate patients with arthrogryposis submitted to extensive surgical treatment with a minimum of 10 years of follow-up regarding the clinical and radiological aspects and the quality of life, using the 36-Item Short Form (SF-36) and the Disease-Specific Instrument (DSI). Methods: A retrospective study selected 33 patients, totaling 64 operated feet. Results: The mean age of the patients was 17.9 years (12-39 years), and the mean follow-up time was 14.8 years (11-17). Amyoplasia represented 78.7% of syndromic diagnoses. Isolated posteromedial lateral release (PMLR) was performed in 21.8% of the feet, 27.2% of which required additional bone surgery, and about 50 feet (78.1%) were submitted to PMLR, lateral column shortening, and/or talectomy. In total, 46 talectomies were performed (71.8% of the feet), out of which 44 were the first procedure of choice. SF-36 questionnaire was evaluated and showed that 93.9% of the patients did not have restrictive and disabling pain, and the same percentage considered themselves as healthy and had good expectations for the future. Conclusion: Arthrogrypotic feet are difficult to treat, require many recurrent surgical procedures, and relapses are the rule. Stiffness is a common feature of these feet, and residual deformities were frequent. Level of Evidence IV; Case Series, Therapeutic Studies

Maps of active layer thickness in northern Alaska by upscaling P-band polarimetric synthetic aperture radar retrievals

Extensive, detailed information on the spatial distribution of active layer thickness (ALT) in northern Alaska and how it evolves over time could greatly aid efforts to assess the effects of climate change on the region and also help to quantify greenhouse gas emissions generated due to permafrost thaw. For this reason, we have been developing high-resolution maps of ALT throughout northern Alaska. The maps are produced by upscaling from high-resolution swaths of estimated ALT retrieved from airborne P-band synthetic aperture radar (SAR) images collected for three different years. The upscaling was accomplished by using hundreds of thousands of randomly selected samples from the SAR-derived swaths of ALT to train a machine learning regression algorithm supported by numerous spatial data layers. In order to validate the maps, thousands of randomly selected samples of SAR-derived ALT were excluded from the training in order to serve as validation pixels; error performance calculations relative to these samples yielded root-mean-square errors (RMSEs) of 7.5–9.1 cm, with bias errors of magnitude under 0.1 cm. The maps were also compared to ALT measurements collected at a number of in situ test sites; error performance relative to the site measurements yielded RMSEs of approximately 11–12 cm and bias of 2.7–6.5 cm. These data are being used to investigate regional patterns and underlying physical controls affecting permafrost degradation in the tundra biome

Decadal-scale hotspot methane ebullition within lakes following abrupt permafrost thaw

Thermokarst lakes accelerate deep permafrost thaw and the mobilization of previously frozen soil organic carbon. This leads to microbial decomposition and large releases of carbon dioxide (CO2) and methane (CH4) that enhance climate warming. However, the time scale of permafrost-carbon emissions following thaw is not well known but is important for understanding how abrupt permafrost thaw impacts climate feedback. We combined field measurements and radiocarbon dating of CH4 ebullition with (a) an assessment of lake area changes delineated from high-resolution (1–2.5 m) optical imagery and (b) geophysical measurements of thaw bulbs (taliks) to determine the spatiotemporal dynamics of hotspot-seep CH4 ebullition in interior Alaska thermokarst lakes. Hotspot seeps are characterized as point-sources of high ebullition that release 14C-depleted CH4 from deep (up to tens of meters) within lake thaw bulbs year-round. Thermokarst lakes, initiated by a variety of factors, doubled in number and increased 37.5% in area from 1949 to 2009 as climate warmed. Approximately 80% of contemporary CH4 hotspot seeps were associated with this recent thermokarst activity, occurring where 60 years of abrupt thaw took place as a result of new and expanded lake areas. Hotspot occurrence diminished with distance from thermokarst lake margins. We attribute older 14C ages of CH4 released from hotspot seeps in older, expanding thermokarst lakes (14CCH4 20 079 ± 1227 years BP, mean ± standard error (s.e.m.) years) to deeper taliks (thaw bulbs) compared to younger 14CCH4 in new lakes (14CCH4 8526 ± 741 years BP) with shallower taliks. We find that smaller, non-hotspot ebullition seeps have younger 14C ages (expanding lakes 7473 ± 1762 years; new lakes 4742 ± 803 years) and that their emissions span a larger historic range. These observations provide a first-order constraint on the magnitude and decadal-scale duration of CH4-hotspot seep emissions following formation of thermokarst lakes as climate warms

Pregnancy-Related Tuberculous Meningitis and Immune Reconstitution Inflammatory Syndrome: A Case Series and Systematic Review

BACKGROUND: Tuberculosis is a leading cause of death among women of reproductive age. However, tuberculous meningitis, the most severe form of extrapulmonary tuberculosis, is rarely discussed in pregnancy despite this being a unique period of immune modulation that may predispose women to active disease. METHODS: We identified and described cases of tuberculous meningitis among pregnant or postpartum women screened during meningitis clinical trials in Uganda from 2018 to 2022. We conducted a systematic literature review via PubMed/Medline and Embase for all English-language publications from 1970 to 10 July 2022, to identify additional cases. RESULTS: We identified 8 cases of pregnancy-related tuberculous meningitis in Ugandan women living with human immunodeficiency virus (HIV) and 40 additional cases via systematic literature review (none HIV-positive). Of all combined cases, 50% (24/48) were diagnosed postpartum; 50% (24/48) had initial onset during pregnancy, of which 38% (9/24) had worsening of symptoms or disease relapse following pregnancy cessation. Diagnosis was missed or delayed in 33% (16/48) of cases. For those with known outcomes, maternal mortality was 23% (11/48) and fetal/neonatal mortality was 30% (13/44). Of maternal survivors, 30% (11/37) had residual neurologic deficits. CONCLUSIONS: The true incidence of tuberculous meningitis in pregnancy or the postpartum period is unclear but likely underappreciated. To date, nearly all published cases have occurred in HIV-negative or otherwise immunocompetent women. Given the well-described physiological immunosuppression during pregnancy and subsequent reconstitution postpartum, physicians must be aware of tuberculous meningitis and pregnancy-related immune reconstitution inflammatory syndrome, especially in countries with a high burden of tuberculosis and in women living with HIV

Forage Consumption and Its Effects on the Performance of Growing Swine-Discussed in Relation to European Wild Boar (Sus scrofa L.) in Semi-Extensive Systems: A Review

Due to its distinct properties, wild boar meat is considered a highly desirable consumer product, in a market that is expanding. Outdoor production is also favoured by consumers who value animal welfare and environmental sustainability when choosing meat products. There is evidence that farms that include pasture for grazing typically have reduced feeding costs. Such production systems can also be more environmentally sustainable as the input (pasture) is inedible to humans, compared to conventional indoor systems, which use human-edible feeds (e.g., soya). However, some wild boar farms have performed poorly compared to those rearing other swine such as hybrid wild boar and domestic pigs. Diet is central to all livestock production and is likely a significant influencing factor of wild boar performance, both in terms of forage consumption and nutritional composition. Other factors may also influence performance, such as weather, behaviour and grazing management. Wild boar production systems hold their own intrinsic value in a growing marketplace. However, information gathered through the study of wild boar has external applications in informing outdoor domestic pig production systems to encourage the use of pasture as part of the habitat of domestic pigs

Baseline Cytomegalovirus Viremia at Cryptococcal Meningitis Diagnosis Is Associated With Long-term Increased Incident TB Disease and Mortality in a Prospective Cohort of Ugandan Adults With HIV.

BACKGROUND: Adults with HIV-associated cryptococcal meningitis have overlapping burdens of cytomegalovirus (CMV) and tuberculosis (TB) coinfections. CMV infection/reactivation is strongly associated with CMV-specific memory T-cell activation and upregulation of type 1 interferons, which may lead to increased risk of TB disease and poor outcomes. METHODS: We conducted a cohort study of 2-week survivors of cryptococcal meningitis during 2010-2021 to determine TB incidence and all-cause mortality over time stratified by baseline CMV status. RESULTS: We followed 497 Ugandans with HIV-associated cryptococcal meningitis for a median (interquartile range) of 4.6 (2.6-53.9) months. Overall, 42% (210/497) developed incident TB disease or died. One-fifth (98/497, 19.7%) developed incident TB disease, and 29% (142/497) of participants died during follow-up. Of 259 participants with CMV viral load measured at baseline, 37% (96/259) had concurrent CMV viremia (defined as anyone with detectable CMV DNA in plasma/serum by qualitative polymerase chain reaction [PCR] detection). Of 59 with measured CMV immunoglobulin G (IgG), 100% had positive CMV IgG antibody serology (≥10 enzyme-linked immunosorbent assay units/mL). CMV viremia was positively associated with higher HIV viral load (196 667 vs 73 295 copies/mL; P = .002) and higher cerebrospinal fluid fungal burden (68 500 vs 14 000 cfu/mL; P = .002) compared with those without. Participants with high-level CMV viremia (defined as CMV viral load ≥1000 IU/mL) had twice the risk of incident TB (subdistribution adjusted hazard ratio [aHR], 2.18; 95% CI, 1.11-4.27) and death (aHR, 1.99; 95% CI, 1.14-3.49) compared with participants with no or low-level CMV viremia. There was no association between the CMV IgG index and the incidence of TB/death (P = .75). CONCLUSIONS: CMV viremia >1000 IU/mL at meningitis diagnosis was associated with increased incident TB disease and mortality during long-term follow-up. Future studies to determine the causal relationship and potential for therapeutic intervention are warranted

A secondary analysis of depression outcomes from a randomized controlled trial of adjunctive sertraline for HIV-associated cryptococcal meningitis.

Background: Depression is a risk factor for worse HIV outcomes in persons living with HIV/AIDS, including engagement-in-care, HIV medication adherence, and retention-in-care. Depression has a prevalence of more than three times as high as in the general population. Despite this, there are few randomized studies of antidepressants in HIV-infected Africans, including those with opportunistic infections. Methods: We enrolled 460 HIV-infected Ugandans with cryptococcal meningitis into a randomized clinical trial of adjunctive sertraline vs placebo (2015-2017). We defined depression using the Center for Epidemiologic Studies Depression Scale (CES-D) score of >15, and severe depression as >26 at one and three months after meningitis diagnosis and initiation of treatment. We evaluated the relationship between sertraline and depression, as well as associations with persistent depression, at three months. Results: At one- and three-months post meningitis diagnosis, 62% (108/174) and 44% (74/169) of all subjects had depression (CES>15), respectively. At three months, sertraline-treated subjects had consistent risk for depression as placebo-treated subjects but were significantly less likely to have severe depression (CES>26) (OR 0.335; 95%CI, 0.130-0.865). Of those with depression at one month, sertraline-treated subjects were less likely than placebo-treated subjects to be depressed at three months (p=0.05). Sertraline was the only factor we found significant in predicting persistent depression at three months among those with depression at one month. Conclusions: Depression is highly prevalent in HIV-infected persons who have survived cryptococcal meningitis. We found that sertraline is associated with a modest reduction in depression in those with depression at baseline and a significant decrease in severe depression