Explore the vast range of titles available.

Changes in the Madden–Julian oscillation (MJO) and its impacts on the South American monsoon season during different El Niño–Southern Oscillation (ENSO) states [El Niño (EN), La Niña (LN), neutral (NT)] are analyzed in the global context of the MJO-propagating anomalies of convection and circulation. The background ENSO-related changes influence several aspects of MJO (relative occurrence of phases, propagation, convection, and teleconnections), and therefore modify the MJO impacts on South America (SA), such as precipitation anomalies and frequency of extreme events, as well as their distribution throughout the MJO cycle. Among the changes are the following: 1) a delay in the teleconnection between the central-east Pacific and SA, from MJO phase 8 in LN (MJOLNphase8) to MJO phase1 in EN (MJOENphase1); 2) enhanced MJO convection in the central-east subtropical South Pacific in MJOLNphases7 + 8 and a little farther east in MJOENphases8 + 1, in a region efficient in generating teleconnections that produce rainfall anomalies over central-east SA (CESA), especially the South Atlantic convergence zone (SACZ), strongest one phase earlier in LN (MJOLNphase8) than in EN (MJOENphase1), and a little shifted east in the latter than in the former; 3) enhancement of the extratropical teleconnection and its impacts over the SACZ in both EN and LN (with regard to NT), indicating nonlinear effects on MJO impacts over SA; 4) predominant increase (or reduction) in the frequency of extreme events over SA regions where both ENSO and MJO contribute in the same direction, with the greatest increase over CESA during EN in MJOENphase1 and over Southeast SA (SESA) inMJOENphase3.

Botanists, ecologists and evolutionary biologists are familiar with the astonishing species richness and endemism of the fynbos of the Cape Floristic Region and the ancient and unique flora of the kwongkan of south-western Australia. These regions represent old climatically-buffered infertile landscapes (OCBILs) that are the basis of a general hypothesis to explain their richness and endemism. However, few ecologists are familiar with the campo rupestre of central and eastern Brazil, an extremely old mountaintop ecosystem that is both a museum of ancient lineages and a cradle of continuing diversification of endemic lineages. Diversification of some lineages of campo rupestre pre-dates diversification of lowlandcerrado, suggesting it may be the most ancient open vegetation in eastern South America. This vegetation comprises more than 5000 plant species, nearly 15 % of Brazil’s plant diversity, in an area corresponding to 0.78 % of its surface. Reviewing empirical data, we scrutinise five predictions of the OCBIL theory, and show that campo rupestre is fully comparable to and remarkably convergent with both  fynbos and kwongkan, and fulfills the criteria for a classic OCBIL. The increasing threats to campo rupestre are compromising ecosystem services and we argue for the implementation of more effective conservation and restoration strategies.

Leptospirosis is a neglected, widespread zoonosis caused by pathogenic species of the genus Leptospira, and is responsible for 60,000 deaths per year. Pathogenic mechanisms of leptospirosis remain poorly understood mainly because targeted mutations or gene silencing in pathogenic Leptospira continues to be inherently inefficient, laborious, costly and difficult to implement. In addition, pathogenic leptospires are highly fastidious and the selection of mutants on solid agar media can take up to 6 weeks. The catalytically inactive Cas9 (dCas9) is an RNA-guided DNA-binding protein from the Streptococcus pyogenes CRISPR/Cas system and can be used for gene silencing, in a strategy termed CRISPR interference (CRISPRi). Here, this technique was employed to silence genes encoding major outer membrane proteins of pathogenic L. interrogans . Conjugation protocols were optimized using the newly described HAN media modified for rapid mutant recovery at 37 °C in 3% CO 2 within 8 days. Complete silencing of LipL32 and concomitant and complete silencing of both LigA and LigB outer membrane proteins were achieved, revealing for the first time that Lig proteins are involved in pathogenic Leptospira serum resistance. Gene silencing in pathogenic leptospires and rapid mutant recovery will facilitate novel studies to further evaluate and understand pathogenic mechanisms of leptospirosis.

BackgroundDrafting is a common technique to reduce the drag experienced by elite runners on races, leading to faster finish times. The tactic has been successfully used in previous marathon world records.In the 2023 Chicago Marathon, Kenyan runner Kelvin Kiptum broke the marathon record after a 2:00:35 finish. This feat is impressive considering the lack of use of drafting, despite the availability of two pacers for the majority of the race.MethodsIn this study, the drag faced by Kiptum and his pacers during the race is calculated by means of computational fluid dynamics (CFD). The performance of each runner is evaluated from an energetic standpoint, and the analysis is extended to include more efficient drafting formations.ResultsRunning in proper formations results in drag reductions in excess of 70% for the main runner. Our results indicate that, by properly using the advantages of drafting, Kiptum could have finished the race at a staggering 1:57:34, a full three minutes better than his own record and 215 s better than the previous world record.ConclusionProper use of drafting does indeed improve the energetic performance of a runner, allowing for lower race times and potentially helping elite runners in breaking the 2-h barrier for a marathon.

Misperceptions about the world’s grassy biomes contribute to their alarming rates of loss due to conversion for agriculture and tree plantations, as well as to forest encroachment. To illustrate the causes and consequences of these misperceptions, we show that the World Resources Institute and the International Union for Conservation of Nature misidentified 9 million square kilometers of ancient grassy biomes as providing “opportunities” for forest restoration. Establishment of forests in these grasslands, savannas, and open-canopy woodlands would devastate biodiversity and ecosystem services. Such undesired outcomes are avoidable if the distinct ecologies and conservation needs of forest and grassy biomes become better integrated into science and policy. To start with, scientists should create maps that accurately depict grassy biomes at global and landscape scales. It is also crucial that international environmental agreements (e.g., the United Nations Framework Convention on Climate Change) formally recognize grassy biomes and their environmental values.

We expand the concept of \"old growth\" to encompass the distinct ecologies and conservation values of the world's ancient grass-dominated biomes. Biologically rich grasslands, savannas, and open-canopy woodlands suffer from an image problem among scientists, policy makers, land managers, and the general public, that fosters alarming rates of ecosystem destruction and degradation. These biomes have for too long been misrepresented as the result of deforestation followed by arrested succession. We now know that grassy biomes originated millions of years ago, long before humans began deforesting. We present a consensus view from diverse geographic regions on the ecological characteristics needed to identify old-growth grasslands and to distinguish them from recently formed anthropogenic vegetation. If widely adopted, the old-growth grassland concept has the potential to improve scientific understanding, conservation policies, and ecosystem management.

The classification of plant species according to the CSR ecological strategy scheme has been proposed as a common language that allows comparison among species, communities, and floras. Although several studies on European continent have demonstrated a consistent association between CSR strategies and key ecosystem processes, studies of this type are still lacking in other ecoregions worldwide. For the first time, the CSR strategy scheme is applied in a tropical plant community. In a Brazilian mountain grassland ecosystem characterized by both high biodiversity and environmental stress, we sampled various functional traits of 48 herbaceous species in stony and sandy grasslands, and evaluated the relationship between CSR strategies and functional traits with several environmental parameters. The extremely infertile soils in the two studied habitats may have acted as a major environmental filter leading to a clear predominance of the stress-tolerant strategy in both communities. However, fine-scale environmental differences between the two communities resulted in the filtering of distinct functional trait values. The sites with coarser soil texture, lower percentage of plant cover and (paradoxically) higher mineral nutrient concentrations favored plants with narrower leaves, higher stress tolerance, lower competitiveness, and higher sclerophylly (i.e., lower specific leaf area and higher leaf dry matter content). The comparison between the functional character of stony and sandy communities evidenced the influence of soil texture and water availability in the environmental filtering. This study highlighted the validity of the CSR classification outside the temperate region where it was originally developed and corroborated.

The Northern Adriatic Sea (NAS) is one of the most overexploited marine ecosystems in Europe. Given the gaps in scientific knowledge regarding the NAS, this study sought Fishers’ Ecological Knowledge (FEK) to determine NAS’ historical baselines for conservation. By interviewing 53 fishers in three ports of northern Italy, estimates of the catch rates of four commercial demersal species were generated over a 60-year period, and perceptions of target and non-target species’ diversity and benthic diversity were analysed in three groups of fishers (i.e. novices, experienced and veterans). Results showed a significant decline in perceived abundance of sole (Solea solea), common cuttlefish (Sepia officinalis) and mantis shrimp (Squilla mantis), and evidence was found of a Shifting Baseline Syndrome (SBS) among novices. Given FEK’s ability to complement scientific knowledge, fishers’ participation in marine management policies and intergenerational communication should be enhanced, to improve the status of marine ecosystems and hinder SBS.

This study investigates how the El Niño phase (EN) of the El Niño-Southern Oscillation (ENSO) influences the Madden-Julian Oscillation (MJO) modulation of cool-season North Pacific atmospheric rivers (ARs) and associated AR-landfall North American precipitation between 1980 and 2020. EN changes the key drivers of MJO-AR connections by shifting MJO-driven convection east of 180° in MJO phases 6–8 and extending the northern Pacific subtropical jet eastward. Under these conditions, the MJO tropical-extratropical teleconnection is triggered east of 180° in phases 7–8, and a persistent cyclonic flow anomaly develops along the United States west coast. Anomalous northeastward integrated water vapor transport (IVT) within the cyclonic flow coupled with the MJO convection over the western (phase 7) and central (phase 8) Pacific increases AR frequency, shifting it to the east over regions that do not show a relationship with EN or MJO alone. Besides enhancing AR activity, EN background conditions increase the number of AR events, their lifetime, and mean intensity from MJO phases 6 through 8, as well as the number of MJO active days, AR initiations, and ARs making landfall over North America in phases 8 − 1. The positive precipitation anomalies and increased frequency of extreme precipitation events associated with landfalling North Pacific ARs related to MJO are also shifted to the east in EN, enhancing and extending rainfall over western North America in phases 6 − 1. Results provide new insight into the drivers of AR activity and associated precipitation along the west coast of North America with implications for improving subseasonal-to-seasonal predictions.