\u3ci\u3eProsopis glandulosa\u3c/i\u3e persistence is facilitated by differential protection of buds during low- and high-energy fires

Rangelands worldwide have experienced significant shifts from grass-dominated to woody-plant dominated states over the past century. In North America, these shifts are largely driven by overgrazing and landscape-scale fire suppression. Such shifts reduce productivity for livestock, can have broad-scale impacts to biodiversity, and are often difficult to reverse. Restoring grass dominance often involves restoring fire as an ecological process. However, many resprouting woody plants persist following disturbance, including fire, by resprouting from protected buds, rendering fire ineffective for reducing resprouting woody plant density. Recent research has shown that extreme fire (high-energy fires during periods of water stress) may reduce resprouting capacity. This previous research did not examine whether high-energy fires alone would be sufficient to cause mortality. We created an experimental framework for assessing the “buds-protection-resources” hypothesis of resprouting persistence under different fire energies. In July–August 2018 we exposed 48 individuals of a dominant resprouting woody plant in the region, honey mesquite (Prosopis glandulosa), to two levels of fire energy (high and low) and root crown exposure (exposed vs unexposed) and evaluated resprouting capacity. We censused basal and epicormic resprouts for two years following treatment. Water stress was moderate for several months leading up to fires but low in subsequent years. Epicormic and basal buds were somewhat protected from lowand high-energy fire. However, epicormic buds were protected in very few mesquites subjected to high-energy fires. High-energy fires decreased survival, caused loss of apical dominance, and left residual dead stems, which may increase chances of mortality from future fires. Basal resprout numbers were reduced by high-energy fires, which may have additional implications for long-term mesquite survival. While the buds, protection, and resources components of resprouter persistence all played a role in resprouting, high-energy fire decreased mesquite survival and reduced resprouting. This suggests that high-energy fires affect persistence mechanisms to different extents than low-energy fires. In addition, high-energy fires during normal rainfall can have negative impacts on resprouting capacity; water stress is not a necessary precursor to honey mesquite mortality from highenergy fire

Exotic herbivores and fire energy drive standing herbaceous biomass but do not alter compositional patterns in a semiarid savanna ecosystem

Questions: Fire regime alterations are pushing open ecosystems worldwide past tipping points where alternative steady states characterized by woody dominance prevail. This reduces the frequency and intensity of surface fires, further limiting their effectiveness for controlling cover of woody plants. In addition, grazing pressure (exotic or native grazers) can reinforce woody encroachment by potentially reducing fine-fuel loads. We investigated the effects of different fire energies on the herbaceous plant community, together with mammalian wildlife herbivory (exotic and native combined) exclusion, to inform best management practices. Location: Texas semi-arid savanna, southern Great Plains, USA. Methods: We conducted an experiment in which we manipulated fire intensity and herbivore access to herbaceous biomass in a split-plot design. We altered fire energy via fuel addition rather than applying fire under different environmental conditions to control for differences in standing biomass and composition attributable to differential plant physiological status and fire season. Results: High-energy fire did not reduce herbaceous biomass or alter plant community composition, although it did increase among-plot variability in composition and forb biomass relative to low-energy fire and non-burned controls. Grazing pressure from native and non-native mammalian herbivores reduced above-ground herbaceous biomass regardless of fire treatments, but did not alter community composition. Conclusions: Managers seeking to apply high-intensity prescribed fire to reduce woody encroachment will not negatively impact herbaceous plant productivity or alter community composition. However, they should be cognizant that repeated fires necessary for greatly reducing woody plants in heavily invaded areas might be difficult to accomplish due to fine-fuel reduction from wild herbivores. High fencing to restrict access by wildlife herbivores or culling might be necessary to build fuels sufficient to conduct high-intensity burns for woody-plant reductio

Needle diseases in Oregon coast range conifers

This publication discusses the environmental requirements of needle diseases, their potential impact on tree vigor, when disease levels signal a problem, and what you can do to minimize damage.Published January 2000. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo

Silviculture and Swiss needle cast : research and recommendations

For the past ten years, Douglas-fir on the Oregon and Washington coast has shown a progressive decrease in height and diameter increment as a result of Swiss needle cast, which is caused by Phaeocryptopus gaeumannii. In this contribution, we discuss the effects of silvicultural operations on Swiss needle cast and recommend specific actions to reduce the severity of the disease. We also suggest a method of assessing the severity of Swiss needle cast damage to a stand based on years of needle retention. Our recommendations are based on disease severity and are designed to discriminate against Douglas-fir when planting, thinning, and harvesting stands suffering low, medium, and high Swiss needle cast severity. These recommendations are based on our collective observations and research being conducted by the Swiss Needle Cast Cooperative

Development and evaluation of low-volume tests to detect and characterize antibodies to SARS-CoV-2

Low-volume antibody assays can be used to track SARS-CoV-2 infection rates in settings where active testing for virus is limited and remote sampling is optimal. We developed 12 ELISAs detecting total or antibody isotypes to SARS-CoV-2 nucleocapsid, spike protein or its receptor binding domain (RBD), 3 anti-RBD isotype specific luciferase immunoprecipitation system (LIPS) assays and a novel Spike-RBD bridging LIPS total-antibody assay. We utilized pre-pandemic (n=984) and confirmed/suspected recent COVID-19 sera taken pre-vaccination rollout in 2020 (n=269). Assays measuring total antibody discriminated best between pre-pandemic and COVID-19 sera and were selected for diagnostic evaluation. In the blind evaluation, two of these assays (Spike Pan ELISA and Spike-RBD Bridging LIPS assay) demonstrated >97% specificity and >92% sensitivity for samples from COVID-19 patients taken >21 days post symptom onset or PCR test. These assays offered better sensitivity for the detection of COVID-19 cases than a commercial assay which requires 100-fold larger serum volumes. This study demonstrates that low-volume in-house antibody assays can provide good diagnostic performance, and highlights the importance of using well-characterized samples and controls for all stages of assay development and evaluation. These cost-effective assays may be particularly useful for seroprevalence studies in low and middle-income countries

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Introduction to special issue:New Times Revisited: Britain in the 1980s

The authors in this volume are collectively engaged with a historical puzzle: What happens if we examine the decade once we step out of the shadows cast by Thatcher? That is, does the decade of the 1980s as a significant and meaningful periodisation (equivalent to that of the 1960s) still work if Thatcher becomes but one part of the story rather than the story itself? The essays in this collection suggest that the 1980s only makes sense as a political period. They situate the 1980s within various longer term trajectories that show the events of the decade to be as much the consequence as the cause of bigger, long-term historical processes. This introduction contextualises the collection within the wider literature, before explaining the collective and individual contributions made

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Xylem cavitation in newly planted western hemlock (Tsuga heterophylla (Raf.) Sarg.) seedlings

Reforestation of Pacific Northwest forest-lands with western hemlock has been hindered by unexplained plantation failures. The purpose of this thesis is to provide information that will help in determining the cause of seedling damage and mortality. The studies focused on the relationship between xylem water potential, xylem cavitation and the seedlings subsequent ability to transport water. The initial experiment illustrated that following planting and exposure to water stress newly planted western hemlock seedlings were unable to transport sufficient water to meet transpirational demand. Hydraulic conductance declined from 1.O1ug cm-2 s-1 MPa-1 to O.l6ug cm-2 s-1 MPa-1 over an 11 day period. In the second study xylem cavitation was detected almost immediately following planting in moist soils and in one case rapidly escalating diurnal cavitation rates ended in seedling mortality. There did not appear to be any correlation between cavitation rates and ambient temperature and relative humidity. In addition it was determined that xylem cavitation was initiated when xylem water potentials reached -1.5MPa. A peak rate of 90 events per minute was experienced at -3.6MPa declining thereafter as the number of water filled tracheids decreased. A similar pattern of cavitation rate and water potential was experienced when monitoring intact potted seedlings in a greenhouse. The cavitation rates followed a diurnal pattern however which declined with increasing xylem water potentials. The final experiment in this series measured the impact of xylem cavitation on hydraulic conductivity. A 30% loss in hydraulic conductivity was experienced following a water potential between -2.5 and -3.OMPa. A complete loss was experienced following water potentials of -4.OMPa. Following planting, western hemlock seedlings experience water stress due to the inability of the root system to supply sufficient water to meet transpirational demand. This water stress results in water potentials which are sufficiently negative to cause xylem cavitation and embolism formation. The embolized tracheids result in a decline in hydraulic conductance and subsequent adjustments in stomatal aperture and leaf area. Without adjustments to reduce transpirational demand the seedling can experience severe enough cavitation to result in mortality

Pre-experimental sleep effects on directed forgetting

A directed forgetting (DF) paradigm was used to compare the remembering and forgetting of participants with good sleep quality to those with poor sleep quality and the presence of insomnia symptoms. This study implemented a point system in place of remember and forget instructions in a DF task with the goal of computing DF costs and benefits. Relations among memory, sleep, and working memory capacity (WMC) were also examined. DF benefits were observed in both groups, with negative costs found for participants without the presence of insomnia symptoms. WMC was found to be related to memory for positive point items only, and did not differ based on sleep quality. These results suggest that the presence of self-reported insomnia symptoms does not affect performance on a DF task