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Vaccine development for vector-borne pathogens may be accelerated through the use of relevant challenge models, as has been the case for malaria. Because of the demonstrated biological importance of vector-derived molecules in establishing natural infections, incorporating natural challenge models into vaccine development strategies may increase the accuracy of predicting efficacy under field conditions. Until recently, however, there was no natural challenge model available for the evaluation of vaccine candidates against visceral leishmaniasis. We previously demonstrated that a candidate vaccine against visceral leishmaniasis containing the antigen LEISH-F3 could provide protection in preclinical models and induce potent T-cell responses in human volunteers. In the present study, we describe a next generation candidate, LEISH-F3+, generated by adding a third antigen to the LEISH-F3 di-fusion protein. The rationale for adding a third component, derived from cysteine protease (CPB), was based on previously demonstrated protection achieved with this antigen, as well as on recognition by human T cells from individuals with latent infection. Prophylactic immunization with LEISH-F3+formulated with glucopyranosyl lipid A adjuvant in stable emulsion significantly reduced both Leishmania infantum and L. donovani burdens in needle challenge mouse models of infection. Importantly, the data obtained in these infection models were validated by the ability of LEISH-F3+/glucopyranosyl lipid A adjuvant in stable emulsion to induce significant protection in hamsters, a model of both infection and disease, following challenge by L. donovani –infected Lutzomyia longipalpis sand flies, a natural vector. This is an important demonstration of vaccine protection against visceral leishmaniasis using a natural challenge model. Leishmaniasis: Improved vaccine candidate demonstrates protection A research collaboration between the United States and Bangladesh has improved its own vaccine candidate and demonstrated it to be effective. The vaccine’s target, visceral leishmaniasis, is a deadly parasitic disease transmitted via the bites of sandflies. The collaboration, led by Steven Reed of the United States’ Infectious Disease Research Institute, previously developed a vaccine that presents two parasite-derived proteins (antigens) to a host’s immune system, allowing it to build a defense. The new vaccine candidate contains three antigens and has shown to confer disease resistance to hamsters who were subsequently exposed to infected sandflies. This is the first time a vaccine for visceral leishmaniasis has stood up in tests where the host has been infected through natural methods, which inspires confidence in the vaccine’s capacity to work in the wild.

Accurate volcanic hazard assessments rely on a detailed understanding of the timing of past eruptions. While radiometric methods like 40Ar/39Ar or K/Ar are by far the most conventional lava flow dating tools, their low resolution for young (<20 ka) deposits interferes with the development of precise chronologies of recent effusive activity on most volcanoes. Mt Ruapehu (Aotearoa / New Zealand) has produced many lava flows throughout its history, but the precise timing of many recent eruptions remains largely unknown. In this study, we use cosmogenic 3He exposure dating to provide 23 eruption ages of young lava flows at Ruapehu. We then compare our results with existing 40Ar/39Ar and paleomagnetic constraints, highlighting the value of cosmogenic nuclide exposure dating in refining recent eruptive chronologies. Of the 23 sampled flows, 16 provided robust eruption ages (5 %–20 % internal 2σ; n≥3) between ca. 20 and 8 ka, except for one lava flow that erupted at around 43 ka, and their age distribution indicates that, during the last 20 kyr, effusive activity at Ruapehu peaked at 17–12 ka and at 9–7.5 ka. Nearly identical eruption ages of lavas located in different flanks of the volcanic edifice suggest concurrent activity from multiple vents during relatively short time intervals (0–2 kyr) at around 13, 10, and 8 ka. We analysed four individual lava flows previously dated by 40Ar/39Ar, two of which yield eruption ages older than the older limit of the 2σ interval of the radiometric dates, but the good clustering of individual samples from our sites suggests that our results better represent the real eruption age of these flows. Our 3He-based chronology shows excellent agreement with paleomagnetic constraints, suggesting that production rate uncertainties are unlikely to impact the accuracy of our eruption ages. This study demonstrates how cosmogenic nuclide dating can provide greater detail on the recent effusive chronology of stratovolcanoes, helping to resolve the low resolution of and difficulty in applying radiometric dating methods to young lava flows.

A recent chemical explosive test in P-Tunnel at the Nevada National Security Site, Nevada, USA, was conducted to better understand how signals propagate from explosions in the subsurface. A primary signal of interest is the migration of gases that can be used to differentiate chemical from nuclear explosions. Gas migration is highly dependent on the rock permeability which is notoriously difficult to determine experimentally in the field due to a potentially large dependence on the scale over which measurements are made. Here, we present pre-explosion permeability estimates to characterize the geologic units surrounding the recent test. Permeability measurements were made at three scales of increasing size: core samples (≈2 cm), borehole packer system tests (≈1 m), and a pre-shot cavity pressurization test (> 10 m) across ten tuff units. Permeability estimates based on core measurements showed little difference from borehole packer tests. However, permeability in most rock units calibrated from cavity pressurization tests resulted in higher permeability estimates by up to two orders of magnitude. Here, we demonstrate that the scale of the measurement significantly impacts the characterization efforts of hydraulic properties in volcanic tuff, and that local-scale measurements (< 10 m scale) do not incorporate enough heterogeneity to accurately predict field-scale flow and mass transport.

Wildbranch: An Anthology of Nature, Environmental, and Place-based Writing is a powerful collection of mostly unpublished essays and poetry by both prominent American environmental writers and exciting new voices. The poetry and essays by more than fifty contributors offer the reader glimpses into places as diverse as a forest in West Africa, the moors of Ireland, the canyons of the Sonoran desert mountains, and the fields of New England, and they reflect the varied perspectives of field biologists, hunters, farmers, environmental educators, wilderness guides, academics, writers, and artists. The collection is an intimate portrait of the natural world drawn through the wisdom, ecological consciousness, and open hearts of these exceptional contributors. The Wildbranch Writing Workshop, cosponsored by Orion magazine and Sterling College, has encouraged thoughtful natural history, outdoor, and environmental writing for more than twenty years. The Wildbranch faculty has included its founder E. Anne Proulx, the essayists Edward Hoagland, Janisse Ray, and Scott Russell Sanders, the poet Alison Hawthorne Deming, and many other notable authors. Many have work included in the anthology. Winner of the New Mexico Book Association's Southwest Book Design & Production Awards for Excellence in the category Trade Books: Non-illustrated.