The tree growth-herbivory relationship depends on functional traits across forest biodiversity experiments.

While studies have demonstrated that higher tree species richness can increase forest productivity, the relationships between tree species richness, tree growth and herbivore damage remain insufficiently explored. Here we investigate these linkages using data from 8,790 trees across 80 species in 9 biodiversity experiments, spanning temperate and subtropical biomes. Despite considerable geographic variation, we reveal an overall positive relationship between tree species richness and insect herbivory, as well as between tree growth and herbivory, at individual, species and community levels.

Canopy complexity drives positive effects of tree diversity on productivity in two tree diversity experiments.

Forest canopy complexity (i.e., the three-dimensional structure of the canopy) is often associated with increased species diversity as well as high primary productivity across natural forests.

Tree diversity enhances predation by birds but not by arthropods across climate gradients.

Tree diversity can promote both predator abundance and diversity. However, whether this translates into increased predation and top-down control of herbivores across predator taxonomic groups and contrasting environmental conditions remains unresolved. We used a global network of tree diversity experiments (TreeDivNet) spread across three continents and three biomes to test the effects of tree species richness on predation across varying climatic conditions of temperature and precipitation.

Effects of plant diversity on productivity strengthen over time due to trait-dependent shifts in species overyielding.

Plant diversity effects on community productivity often increase over time. Whether the strengthening of diversity effects is caused by temporal shifts in species-level overyielding (i.e.

Comparative transcriptomics of the chilling stress response in two Asian mangrove species, Bruguiera gymnorhiza and Rhizophora apiculata.

Low temperatures largely determine the geographic limits of plant species by reducing survival and growth. Inter-specific differences in the geographic distribution of mangrove species have been associated with cold tolerance, with exclusively tropical species being highly cold-sensitive and subtropical species being relatively cold-tolerant. To identify species-specific adaptations to low temperatures, we compared the chilling stress response of two widespread Indo-West Pacific mangrove species from Rhizophoraceae with differing latitudinal range limits-Bruguiera gymnorhiza (L.

Positive tree diversity effects on arboreal spider abundance are tied to canopy cover in a forest experiment.

Human actions are decreasing the diversity and complexity of forests, and a mechanistic understanding of how these changes affect predators is needed to maintain ecosystem services, including pest regulation. Using a large-scale tree diversity experiment, we investigate how spiders respond to trees growing in plots of single or mixed species combinations (4 or 12) by repeatedly sampling 540 trees spanning 15 species. In 2019 (6 years post-establishment), spider responses to tree diversity varied by tree species.

The effect of vitamin C on nitroglycerin-mediated vasodilation in individuals with and without the aldehyde dehydrogenase 2 polymorphism.

Aims: To mediate its pharmacodynamic effects, glyceryl trinitrate (GTN) requires bioactivation, by which it releases nitric oxide or a nitric oxide moiety. The exact mechanism of GTN bioactivation remains uncertain. Mitochondrial aldehyde dehydrogenase (ALDH-2) has been proposed as the primary enzyme responsible for this bioactivation process.

Acute resource pulses from periodical cicadas propagate to belowground food webs but do not affect tree performance.

Acute resource pulses can have dramatic legacies for organismal growth, but the legacy effects of resource pulses on broader aspects of community structure and ecosystem processes are less understood. Mass emergence of periodical cicadas (Magicicada spp.) provides an excellent opportunity to shed light on the influence of resource pulses on community and ecosystem dynamics: the adults emerge every 13 or 17 years in vast numbers over much of eastern North America, with a smaller but still significant number becoming incorporated into forest food webs.

Insectivorous birds reduce herbivory but do not increase mangrove growth across productivity zones.

Top-down effects of predators and bottom-up effects of resources are important drivers of community structure and function in a wide array of ecosystems. Fertilization experiments impose variation in resource availability that can mediate the strength of predator impacts, but the prevalence of such interactions across natural productivity gradients is less clear. We studied the joint impacts of top-down and bottom-up factors in a tropical mangrove forest system, leveraging fine-grained patchiness in resource availability and primary productivity on coastal cays of Belize.

Advances in Our Clinical Understanding of Autonomic Regulation Therapy Using Vagal Nerve Stimulation in Patients Living With Heart Failure.

The ANTHEM-HF, INOVATE-HF, and NECTAR-HF clinical studies of autonomic regulation therapy (ART) using vagus nerve stimulation (VNS) systems have collectively provided dose-ranging information enabling the development of several working hypotheses on how stimulation frequency can be utilized during VNS for tolerability and improving cardiovascular outcomes in patients living with heart failure (HF) and reduced ejection fraction (HFrEF). Changes in heart rate dynamics, comprising reduced heart rate (HR) and increased HR variability, are a biomarker of autonomic nerve system engagement and cardiac control, and appear to be sensitive to VNS that is delivered using a stimulation frequency that is similar to the natural operating frequency of the vagus nerve. Among prior studies, the ANTHEM-HF Pilot Study has provided the clearest evidence of autonomic engagement with VNS that was delivered using a stimulation frequency that was within the operating range of the vagus nerve.

Long-term Outcomes of Adults With Tricuspid Regurgitation Following Transcatheter Atrial Septal Defect Closure.

Background: Functional tricuspid regurgitation (TR) is a common pathophysiologic condition in adults with ostium secundum atrial septal defect (ASD). The aim of this study was to evaluate long-term outcomes following transcatheter ASD closure, which have not been well studied among patients with significant TR.

Methods: We reviewed consecutive adult patients who underwent transcatheter ASD closure at Toronto General Hospital, Ontario, Canada, from 1998 to 2016.

Renal Hemodynamics and Renin-Angiotensin-Aldosterone System Profiles in Patients With Heart Failure.

Objective: Understanding cardiorenal pathophysiology in heart failure (HF) is of clinical importance. We sought to characterize the renal hemodynamic function and the transrenal gradient of the renin-angiotensin-aldosterone system (RAAS) markers in patients with HF and in controls without HF.

Methods: In this post hoc analysis, the glomerular filtration rate (GFR), effective renal plasma flow (ERPF) and transrenal gradients (arterial-renal vein) of angiotensin converting enzyme (ACE), aldosterone, and plasma renin activity (PRA) were measured in 47 patients with HF and in 24 controls.

Mapping carbon accumulation potential from global natural forest regrowth.

To constrain global warming, we must strongly curtail greenhouse gas emissions and capture excess atmospheric carbon dioxide. Regrowing natural forests is a prominent strategy for capturing additional carbon, but accurate assessments of its potential are limited by uncertainty and variability in carbon accumulation rates. To assess why and where rates differ, here we compile 13,112 georeferenced measurements of carbon accumulation.

Chemical novelty facilitates herbivore resistance and biological invasions in some introduced plant species.

Ecological release from herbivory due to chemical novelty is commonly predicted to facilitate biological invasions by plants, but has not been tested on a community scale. We used metabolomics based on mass spectrometry molecular networks to assess the novelty of foliar secondary chemistry of 15 invasive plant species compared to 46 native species at a site in eastern North America. Locally, invasive species were more chemically distinctive than natives.

Inverse relationship of subjective daytime sleepiness to mortality in heart failure patients with sleep apnoea.

Aims: Patients with sleep apnoea (SA) and heart failure (HF) are less sleepy than SA patients without HF. HF and SA both increase sympathetic nervous system activity (SNA). SNA can augment alertness.

Tree diversity promotes growth of late successional species despite increasing deer damage in a restored forest.

The role of tree diversity in restored forests and its impact on key ecological processes like growth and resistance to herbivory has become increasingly important. We analyzed height growth and white-tailed deer Odocoileus virginianus browsing damage to saplings of 16 broadleaved tree species in a large-scale (13 ha) reforestation experiment in Maryland, USA, where we manipulated tree diversity in 70 1,225-m plots. After four growing seasons, higher plot-level tree richness led to increased deer browsing damage (i.

Comparison of symptomatic and functional responses to vagus nerve stimulation in ANTHEM-HF, INOVATE-HF, and NECTAR-HF.

Aims: Clinical studies of vagal nerve stimulation (VNS) for heart failure with reduced ejection fraction have had mixed results to date. We sought to compare VNS delivery and associated changes in symptoms and function in autonomic regulation therapy via left or right cervical vagus nerve stimulation in patients with chronic heart failure (ANTHEM-HF), increase of vagal tone in heart failure (INOVATE-HF), and neural cardiac therapy for heart failure (NECTAR-HF) for hypothesis generation.

Methods And Results: Descriptive statistics were used to analyse data from the public domain for differences in proportions using Pearson's chi-square test, differences in mean values using Student's unpaired t-test, and differences in changes of mean values using two-sample t-tests.

Comparison of short-acting versus extended-release nifedipine: Effects on hemodynamics and sympathetic activity in patients with stable coronary artery disease.

We investigated the impact of short-acting and extended release nifedipine on sympathetic activity using radiotracer methodology in patients with stable coronary artery disease in order to more accurately document the response of the sympathetic nervous system to different formulations of this dihydropyridine calcium channel antagonist. Participants were randomized to placebo, short-acting or extended release nifedipine for 7-10 days. On the final day, systemic blood pressure, cardiac filling pressures, cardiac output, plasma norepinephrine (NE) and total body NE spillover were measured at baseline (time 0) and repeated at intervals for 6 hours.

Sodium Glucose Cotransporter-2 Inhibition and Cardiorenal Protection: JACC Review Topic of the Week.

Poorly controlled type 2 diabetes mellitus is associated with the development of cardiovascular and renal complications, resulting in significant morbidity and mortality. Intensive glycemic control has been a major focus for clinical trials and novel drug development. However, narrow treatment strategies developed strictly for glycemic control did not confer a large risk reduction in cardiovascular events.

Impact of Autonomic Regulation Therapy in Patients with Heart Failure: ANTHEM-HFrEF Pivotal Study Design.

Background: The ANTHEM-HFrEF (Autonomic Regulation Therapy to Enhance Myocardial Function and Reduce Progression of Heart Failure with Reduced Ejection Fraction) pivotal study is an adaptive, open-label, randomized, controlled study evaluating whether autonomic regulation therapy will benefit patients with advanced HFrEF. While early-phase studies have supported potential use of vagus nerve stimulation to deliver autonomic regulation therapy for HFrEF, results of larger clinical trials have been inconsistent. The ANTHEM-HFrEF study uses a novel design, with adaptive sample size selection, evaluating effects on morbidity and mortality as well as symptoms and function.

Climate-driven regime shifts in a mangrove-salt marsh ecotone over the past 250 years.

Climate change is driving the tropicalization of temperate ecosystems by shifting the range edges of numerous species poleward. Over the past few decades, mangroves have rapidly displaced salt marshes near multiple poleward mangrove range limits, including in northeast Florida. It is uncertain whether such mangrove expansions are due to anthropogenic climate change or natural climate variability.

Resting and recruitable endothelial function - Evidence of two distinct circadian patterns.

Background: Evidence of a circadian rhythm in endothelium-dependent vasomotor function, with a nadir in Flow-Mediated Dilation (FMD) in the early morning hours, has been previously reported. These changes have been proposed to be one of the mechanisms explaining the circadian pattern in the incidence of cardiovascular events. We set out to investigate the circadian rhythm of FMD, low-flow mediated dilation (L-FMC) and sympathetic vascular tone.