Topographic controls on soil nitrogen availability in a lowland tropical forest

Geomorphic position often correlates with nutrient cycling across landscapes. In tropical forests, topography is known to influence phosphorus (P) availability, but its effect on nitrogen (N) cycling has received less exploration, especially in lowland forests where widespread N richness is frequently assumed. Here, we report significant effects of topographic slope and landscape position on multiple aspects of the N cycle across a highly dissected lowland tropical forest on the Osa Peninsula, Costa Rica. A suite of N cycle metrics measured along a topographic sequence revealed a distinct gradient in N availability. Values of soil d15N, inorganic N pools, net nitrification rates, and nitrification potentials were all substantially lower on a flanking steep hillslope (;288) compared to a relatively flat ridge top (;68), indicating lower N availability and a less open N cycle in steep parts of the landscape. Slope soils also hosted smaller total carbon and nitrogen stocks and notably less weathered soil minerals than did ridge soils. These latter findings suggest that elevated N loss resulting from high rates of soil and particulate organic matter erosion could underpin the spatial variation in N cycling and availability. Expanding our analysis to the larger study landscape, a strong negative linear relationship between soil d15N values and surface slope angles was observed. N isotope mass balance models suggest that this pattern is most plausibly explained by an increase in N loss via erosive, non-fractioning pathways from steep zones, as most other variables commonly assumed to affect soil d15N values (such as temperature, precipitation, and vegetation type) did not vary across the sampled region. Together, these results reveal notable hillslope-scale variation in N richness and suggest an important role for nonfractionating N loss in the maintenance of this pattern. Such findings highlight the importance of geomorphology and the significant capacity of erosion to influence N availability in steepland ecosystems

Voluntary Exercise Reduces Alzheimer’s-like Pathology After Inflammation in Mice

Current global statistics estimate that 44.4 million people are afflicted with dementia, and that 50%-75% of these patients suffer from Alzheimer’s disease (AD; Prince et al. 2013). AD, a progressive disorder categorized by neuronal and behavioral deterioration, is the 6th leading cause of death in America (Alz facts and figure 2012). One hallmark pathology of AD is the presence of amyloid-beta (Aβ) in the brain, which can limit cell-to-cell communication, leading to cognitive deficits, and neuronal cell death. Although the exact origins of this disease still remain unknown, one possible catalyst of AD pathology is inflammation. Our lab has previously shown that 7 consecutive peripheral injections of a bacterial mimetic led to systemic inflammation, increased levels of Ab in the brain, and cognitive dysfunction (Kahn et al., 2012; Weintraub et al., 2013). Currently there are very few effective treatments that diminish AD symptomology. One documented way to decrease inflammation without the use of pharmaceuticals is through regular physical exercise (Cho et al., 2003; Cotman & Berchtold, 2002; Cotman et al., 2007). The present study tested the hypothesis that voluntary exercise would decrease the level of brain Ab following inflammation. Interestingly, we found that two weeks of voluntary wheel running after inflammation led to a reduction of Ab when compared to sedentary recovery. These results indicate that exercise may be an effective modality to reduce AD-like pathology, and that these effects appear to be facilitated by higher versus lower levels of exercise, as measured by total distance run

Steering Operational Synergies in Terrestrial Observation Networks: Opportunity for Advancing Earth System Dynamics Modelling

Advancing our understanding of Earth system dynamics (ESD) depends on the development of models and other analytical tools that apply physical, biological, and chemical data. This ambition to increase understanding and develop models of ESD based on site observations was the stimulus for creating the networks of Long-Term Ecological Research (LTER), Critical Zone Observatories (CZOs), and others. We organized a survey, the results of which identified pressing gaps in data availability from these networks, in particular for the future development and evaluation of models that represent ESD processes, and provide insights for improvement in both data collection and model integration. From this survey overview of data applications in the context of LTER and CZO research, we identified three challenges: (1) widen application of terrestrial observation network data in Earth system modelling, (2) develop integrated Earth system models that incorporate process representation and data of multiple disciplines, and (3) identify complementarity in measured variables and spatial extent, and promoting synergies in the existing observational networks. These challenges lead to perspectives and recommendations for an improved dialogue between the observation networks and the ESD modelling community, including co-location of sites in the existing networks and further formalizing these recommendations among these communities. Developing these synergies will enable cross-site and cross-network comparison and synthesis studies, which will help produce insights around organizing principles, classifications, and general rules of coupling processes with environmental conditions

Leveraging environmental research and observation networks to advance soil carbon science

Soil organic matter (SOM) is a critical ecosystem variable regulated by interacting physical, chemical and biological processes. Collaborative efforts to integrate perspectives, data, and models from interdisciplinary research and observation networks can significantly advance predictive understanding of SOM. We outline how integrating three networks – the Long‐Term Ecological Research, with a focus on ecological dynamics, the Critical Zone Observatories with strengths in landscape/geologic context, and the National Ecological Observatory Network with standardized multi‐scale measurements—can advance SOM knowledge. This integration requires improved data dissemination and sharing, coordinated data collection activities, and enhanced collaboration between empiricists and modelers within and across networks

SoDaH: the SOils DAta Harmonization database, an open-source synthesis of soil data from research networks, version 1.0

Data collected from research networks present opportunities to test theories and develop models about factors responsible for the long-term persistence and vulnerability of soil organic matter (SOM). Synthesizing datasets collected by different research networks presents opportunities to expand the ecological gradients and scientific breadth of information available for inquiry. Synthesizing these data is challenging, especially considering the legacy of soil data that have already been collected and an expansion of new network science initiatives. To facilitate this effort, here we present the SOils DAta Harmonization database (SoDaH; https://lter.github.io/som-website, last access: 22 December 2020), a flexible database designed to harmonize diverse SOM datasets from multiple research networks. SoDaH is built on several network science efforts in the United States, but the tools built for SoDaH aim to provide an open-access resource to facilitate synthesis of soil carbon data. Moreover, SoDaH allows for individual locations to contribute results from experimental manipulations, repeated measurements from long-term studies, and local- to regional-scale gradients across ecosystems or landscapes. Finally, we also provide data visualization and analysis tools that can be used to query and analyze the aggregated database. The SoDaH v1.0 dataset is archived and available at https://doi.org/10.6073/pasta/9733f6b6d2ffd12bf126dc36a763e0b4 (Wieder et al., 2020)

Genetic risk of Parkinson disease and progression:: An analysis of 13 longitudinal cohorts.

OBJECTIVE: To determine if any association between previously identified alleles that confer risk for Parkinson disease and variables measuring disease progression. METHODS: We evaluated the association between 31 risk variants and variables measuring disease progression. A total of 23,423 visits by 4,307 patients of European ancestry from 13 longitudinal cohorts in Europe, North America, and Australia were analyzed. RESULTS: We confirmed the importance of GBA on phenotypes. GBA variants were associated with the development of daytime sleepiness (p.N370S: hazard ratio [HR] 3.28 [1.69-6.34]) and possible REM sleep behavior (p.T408M: odds ratio 6.48 [2.04-20.60]). We also replicated previously reported associations of GBA variants with motor/cognitive declines. The other genotype-phenotype associations include an intergenic variant near LRRK2 and the faster development of motor symptom (Hoehn and Yahr scale 3.0 HR 1.33 [1.16-1.52] for the C allele of rs76904798) and an intronic variant in PMVK and the development of wearing-off effects (HR 1.66 [1.19-2.31] for the C allele of rs114138760). Age at onset was associated with TMEM175 variant p.M393T (-0.72 [-1.21 to -0.23] in years), the C allele of rs199347 (intronic region of GPNMB, 0.70 [0.27-1.14]), and G allele of rs1106180 (intronic region of CCDC62, 0.62 [0.21-1.03]). CONCLUSIONS: This study provides evidence that alleles associated with Parkinson disease risk, in particular GBA variants, also contribute to the heterogeneity of multiple motor and nonmotor aspects. Accounting for genetic variability will be a useful factor in understanding disease course and in minimizing heterogeneity in clinical trials.The Intramural Research Program the National Institute on Aging (NIA, Z01-AG000949-02), Biogen Idec, and the Michael J Fox Foundation for Parkinson’s Researc

Use of prasugrel vs clopidogrel and outcomes in patients with acute coronary syndrome undergoing percutaneous coronary intervention in contemporary clinical practice: Results from the PROMETHEUS study.

BACKGROUND AND OBJECTIVES: We sought to determine the frequency of use and association between prasugrel and outcomes in acute coronary syndrome patients undergoing percutaneous coronary intervention (PCI) in clinical practice. METHODS: PROMETHEUS was a multicenter observational registry of acute coronary syndrome patients undergoing PCI from 8 centers in the United States that maintained a prospective PCI registry for patient outcomes. The primary end points were major adverse cardiovascular events at 90days, a composite of all-cause death, nonfatal myocardial infarction, stroke, or unplanned revascularization. Major bleeding was defined as any bleeding requiring hospitalization or blood transfusion. Hazard ratios (HRs) were generated using multivariable Cox regression and stratified by the propensity to treat with prasugrel. RESULTS: Of 19,914 patients (mean age 64.4years, 32% female), 4,058 received prasugrel (20%) and 15,856 received clopidogrel (80%). Prasugrel-treated patients were younger with fewer comorbid risk factors compared with their counterparts receiving clopidogrel. At 90days, there was a significant association between prasugrel use and lower major adverse cardiovascular event (5.7% vs 9.6%, HR 0.58, 95% CI 0.50-0.67, P<.0001) and bleeding (1.9% vs 2.9%, HR 0.65, 95% CI 0.51-0.83, P<.001). After propensity stratification, associations were attenuated and no longer significant for either outcome. Results remained consistent using different approaches to adjusting for potential confounders. CONCLUSIONS: In contemporary clinical practice, patients receiving prasugrel tend to have a lower-risk profile compared with those receiving clopidogrel. The lower ischemic and bleeding events associated with prasugrel use were no longer evident after accounting for these baseline differences

Differences in the Presentation and Progression of Parkinson's Disease by Sex.

BACKGROUND: Previous studies reported various symptoms of Parkinson's disease (PD) associated with sex. Some were conflicting or confirmed in only one study. OBJECTIVES: We examined sex associations to PD phenotypes cross-sectionally and longitudinally in large-scale data. METHODS: We tested 40 clinical phenotypes, using longitudinal, clinic-based patient cohorts, consisting of 5946 patients, with a median follow-up of 3.1 years. For continuous outcomes, we used linear regressions at baseline to test sex-associated differences in presentation, and linear mixed-effects models to test sex-associated differences in progression. For binomial outcomes, we used logistic regression models at baseline and Cox regression models for survival analyses. We adjusted for age, disease duration, and medication use. In the secondary analyses, data from 17 719 PD patients and 7588 non-PD participants from an online-only, self-assessment PD cohort were cross-sectionally evaluated to determine whether the sex-associated differences identified in the primary analyses were consistent and unique to PD. RESULTS: Female PD patients had a higher risk of developing dyskinesia early during the follow-up period, with a slower progression in activities of daily living difficulties, and a lower risk of developing cognitive impairments compared with male patients. The findings in the longitudinal, clinic-based cohorts were mostly consistent with the results of the online-only cohort. CONCLUSIONS: We observed sex-associated contributions to PD heterogeneity. These results highlight the necessity of future research to determine the underlying mechanisms and importance of personalized clinical management. © 2020 International Parkinson and Movement Disorder Society.This study was supported by the Intramural Research Program the National Institute on Aging (NIA, Z01-AG000949-02), Biogen Idec, and the Michael J Fox Foundation for Parkinson’s Research