26 research outputs found

    Character and spatial distribution of OH/H<SUB>2</SUB>O on the surface of the moon seen by M<SUP>3</SUP> on Chandrayaan-1

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    The search for water on the surface of the anhydrous Moon had remained an unfulfilled quest for 40 years. However, the Moon Mineralogy Mapper (M3) on Chandrayaan-1 has recently detected absorption features near 2.8 to 3.0 micrometers on the surface of the Moon. For silicate bodies, such features are typically attributed to hydroxyl- and/or water-bearing materials. On the Moon, the feature is seen as a widely distributed absorption that appears strongest at cooler high latitudes and at several fresh feldspathic craters. The general lack of correlation of this feature in sunlit M3 data with neutron spectrometer hydrogen abundance data suggests that the formation and retention of hydroxyl and water are ongoing surficial processes. Hydroxyl/water production processes may feed polar cold traps and make the lunar regolith a candidate source of volatiles for human exploration

    Nothing a Hot Bath Won't Cure: Infection Rates of Amphibian Chytrid Fungus Correlate Negatively with Water Temperature under Natural Field Settings

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    Dramatic declines and extinctions of amphibian populations throughout the world have been associated with chytridiomycosis, an infectious disease caused by the pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd). Previous studies indicated that Bd prevalence correlates with cooler temperatures in the field, and laboratory experiments have demonstrated that Bd ceases growth at temperatures above 28°C. Here we investigate how small-scale variations in water temperature correlate with Bd prevalence in the wild. We sampled 221 amphibians, including 201 lowland leopard frogs (Rana [Lithobates] yavapaiensis), from 12 sites in Arizona, USA, and tested them for Bd. Amphibians were encountered in microhabitats that exhibited a wide range of water temperatures (10–50°C), including several geothermal water sources. There was a strong inverse correlation between the water temperature in which lowland leopard frogs were captured and Bd prevalence, even after taking into account the influence of year, season, and host size. In locations where Bd was known to be present, the prevalence of Bd infections dropped from 75–100% in water <15°C, to less than 10% in water >30°C. A strong inverse correlation between Bd infection status and water temperature was also observed within sites. Our findings suggest that microhabitats where water temperatures exceed 30°C provide lowland leopard frogs with significant protection from Bd, which could have important implications for disease dynamics, as well as management applications

    The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

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    INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

    Recent northward range expansion of the parthenogenetic lizard Aspidoscelis tesselatus in Colorado and the distributional enigma posed by pattern-classes C and D at the northern range periphery

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    The range of the parthenogenetic lizard Aspidoscelis tesselatus extends from eastern Chihuahua, Mexico, to southeastern Colorado, USA. In Colorado, pattern-class D, source of the neotype of the species, is syntopic with the more widely distributed pattern-class C only in Ninemile Valley of the Purgatoire River, beyond which, in all directions, these pattern classes are allopatric. We identify a recent northward range expansion of pattern-class C to the same northern latitude attained by pattern-class D, thereby establishing a latitudinal baseline for the species. The two northern arrays of pattern-class C, reported herein, occupied open habitats of sparsely distributed shrubs on rocky slopes, whereas the northernmost arrays of pattern-class D were using juniper woodland. Although this allopatric arrangement suggests ecological segregation of pattern classes, we provide an example of pattern-class C in juniper woodland only ca. 11 km south of the new records, which suggests that other factors could be involved

    Michelle\u27s Lizard: Identity, relationships, and ecological status of an array of parthenogenetic Lizards (Genus Aspidoscelis: Squamata: Teiidae) in Colorado, USA

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    Using a shared photograph, we identified a lizard captured by a young naturalist in 1995 in La Junta, Otero County, Colorado, USA, to either triploid parthenogenetic Colorado Checkered Whiptail (Aspidoscelis neotesselata) or diploid parthenogenetic Common Checkered Whiptail (A. tesselata). On 12 August 1997, LJL located the species in question near the original La Junta location. The parthenogenetic species at La Junta represents a new pattern class, A. neotesselata D, identity and distinctiveness of which were verified by both univariate and multivariate statistics. We used other triploid lizards from sites ~100 km apart (i.e., A. neotesselata D from La Junta and A. neotesselata A from Pueblo, Pueblo County, Colorado) to verify skin histocompatibility, indicating that each group was derived from the same hybridization event. We also identified a tetraploid hybrid of A. neotesselata x A. sexlineata viridis from La Junta. Of the several small patches of habitat that support A. neotesselata D and Prairie Racerunner (A. sexlineata viridis) at La Junta, only a few are elevated above the flood zone of the adjacent Arkansas River. An unusual characteristic of flat parts of La Junta involves the life cycle of Kochia (Kochia scoparia). This tall-growing annual constitutes ~100% of the vegetative structure on these flats from germination in the spring until die-off in the fall/winter. Searches to increase the known range of A. neotesselata D beyond 1 km of La Junta were unsuccessful. We regard the La Junta array of A. neotesselata D as a naturally occurring peripheral isolate. © 2012. James M. Walker. All Rights Reserved

    Etiology of Febrile Episodes in Patients With Acute Myeloid Leukemia: Results From the Hema e-Chart Registry

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    Several studies have attempted to analyze the epidemiologic patterns of infectious complications in patients with acute myeloid leukemia (AML), although the power of these studies was frequently limited by their retrospective design.1-2 A lively debate currently focuses on the potential of Internet-based software and associated technologies, such as electronic medical records, to simplify reporting, to improve database content, and to optimize the timing of interventions.3-4 Because a well-designed surveillance system is essential for the systematic collection, analysis, and dissemination of data, we designed an electronic medical record system. Methods From March 2007 to March 2009, all newly diagnosed AML candidates for conventional chemotherapy from 17 hematology units in Italy were enrolled in the Hema e-Chart and followed-up prospectively to assess the incidence of febril
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