Abstract This study investigated viruses in bovine respiratory disease (BRD) cases in feedlots, including bovine herpesvirus-1 (BoHV-1), bovine viral diarrhea virus (BVDV), bovine respiratory ...syncytial virus (BRSV), bovine coronaviruses (BoCV) and parainfluenza-3 virus (PI3V). Nasal swabs were collected from 114 cattle on initial BRD treatment. Processing included modified live virus (MLV) vaccination. Seven BRD necropsy cases were included for 121 total cases. Mean number of days on feed before first sample was 14.9 days. Swabs and tissue homogenates were tested by gel based PCR (G-PCR), quantitative-PCR (qPCR) and quantitative real time reverse transcriptase PCR (qRT-PCR) and viral culture. There were 87/114 (76.3%) swabs positive for at least one virus by at least one test. All necropsy cases were positive for at least one virus. Of 121 cases, positives included 18/121 (14.9%) BoHV-1; 19/121 (15.7%) BVDV; 76/121 (62.8%) BoCV; 11/121 (9.1%) BRSV; and 8/121 (6.6%) PI3V. For nasal swabs, G-PCR (5 viruses) detected 44/114 (38.6%); q-PCR and qRT-PCR (4 viruses) detected 81/114 (71.6%); and virus isolation detected 40/114 (35.1%). Most were positive for only one or two tests, but not all three tests. Necropsy cases had positives: 5/7 G-PCR, 5/7 q-PCR and qRT-PCR, and all were positive by cell culture. In some cases, G-PCR and both real time PCR were negative for BoHV-1, BVDV, and PI3V in samples positive by culture. PCR did not differentiate field from vaccines strains of BoHV-1, BVDV, and PI3V. However based on sequencing and analysis, field and vaccine strains of culture positive BoHV-1, BVDV, and PI3V, 11/18 (61.1%) of BoHV-1 isolates, 6/17 (35.3%) BVDV isolates, and 1/10 (10.0%) PI3V identified as vaccine. BRSV was only identified by PCR testing. Interpretation of laboratory tests is appropriate as molecular based tests and virus isolation cannot separate field from vaccine strains. Additional testing using sequencing appears appropriate for identifying vaccine strains.
In this study, gas-phase elemental mercury (Hg0) and related species (including inorganic reactive gaseous mercury (RGM) and particulate mercury (PHg)) were measured at Cheeka Peak Observatory (CPO), ...Washington State, in the marine boundary layer during 2001−2002. Air of continental origin containing anthropogenic pollutants from the urban areas to the east contained on average 5.3% lower Hg0 levels as compared to the marine background. This result is difficult to reconcile since it is known that industrial emissions in our region are sources of Hg0. The rate of removal of Hg0 from a pollution plume necessary to account for our observations is inconsistent with the accepted view of Hg0 as a stable atmospheric pollutant. The largest and most frequent Hg0 loss events occurred in the presence of increased ozone (O3) during the summer. Hg0 and O3 also display diurnal cycles that are out-of-phase with one another. In other seasons Hg0 behavior is less consistent, as we observe weak positive correlations with O3 and occasional Hg0 enhancements in local pollution. RGM and PHg concentrations are enhanced only slightly during Hg0 loss events, comprising a small fraction of the mercury pool (∼3%). Long-range transported pollution of Asian origin was also detected at CPO, and this contains both higher and lower levels of Hg0 as compared to the background with maximum changes being <20%. Here, the more photochemically processed the air mass, as determined by propane/ethane ratios, the more likely we are to observe Hg0 loss. Air from the marine background in summer displays a significant diurnal cycle with a phase that matches the diurnal cycles seen in polluted air masses. A Junge lifetime for Hg0 in the clean marine boundary layer is calculated to be 7.1 months, which is on the low end of previous estimates (0.5−2 yr).
•Vinalia and Cerealia Faculae on Ceres have a common carbonate composition and a variety of morphologies and topographies.•We considered the ejection and deposition of carbonate grains by three ...possible materials: ice, gas and brine.•We find that brine eruption is the most likely formation mechanism explaining bright mantling and central structures.
Vinalia and Cerealia Faculae are bright and salt-rich localized areas in Occator crater on Ceres. The predominance of the near-infrared signature of sodium carbonate on these surfaces suggests their original material was a brine. Here we analyze Dawn Framing Camera's images and characterize the surfaces as composed of a central structure, either a possible depression (Vinalia) or a central dome (Cerealia), and a discontinuous mantling. We consider three materials enabling the ascent and formation of the faculae: ice ascent with sublimation and carbonate particle lofting, pure gas emission entraining carbonate particles, and brine extrusion. We find that a mechanism explaining the entire range of morphologies, topographies, as well as the common composition of the deposits is brine fountaining. This process consists of briny liquid extrusion, followed by flash freezing of carbonate and ice particles, particle fallback, and sublimation. Subsequent increase in briny liquid viscosity leads to doming. Dawn observations did not detect currently active water plumes, indicating the frequency of such extrusions is longer than years.
Observations of a water vapor exosphere around Ceres suggest that the dwarf planet may be episodically outgassing at a rate of ~6 kg s−1 from unknown sources. With data from the Dawn mission as ...constraints, we use a coupled thermal and vapor diffusion model to explore three different configurations of water ice (global buried pore‐filling ice, global buried excess ice, and local exposed surface ice) that could be present on Ceres. We conclude that a buried ice table cannot alone explain the vapor production rates previously measured, but newly exposed surface ice, given the right conditions, can exceed that vapor production rate. Sublimation lag deposits form that bury and darken this surface ice over a large range of timescales (from <1 year to approximately hundreds of kyr) that depend on latitude and ice regolith content. Sublimating water vapor can loft regolith particles from the surface of exposed ice, possibly prolonging the visible lifespan of those areas. We find that this process is only effective for regolith grains smaller than approximately ones of microns.
Key Points
Global buried ice on Ceres cannot match H2O vapor production rates from previous telescopic studies while matching Dawn data
Exposed surface ice can match H2O vapor production rates from previous telescopic studies but is sensitive to timing and location
Regolith particles less than approximately ones of microns in diameter can be lofted from water vapor escaping exposed surface ice
Plain Language Summary
A thin water vapor atmosphere has been previously detected around Ceres, a dwarf planet in the asteroid belt, from space telescope observations. Based on data collected before the Dawn spacecraft's arrival, Ceres potentially contained a large mass of water ice. However, how that water, frozen within Ceres, could be fueling a tenuous water vapor atmosphere has been previously unknown. We explore the possibility of water vapor coming from either a buried ice table or buried surface ice at the same rate detected by previous observations. We use published data from the Dawn spacecraft mission to compare to our thermal and sublimation models. We conclude that given the right place and time, exposed surface ice can generate enough water vapor to replicate Ceres' tenuous atmosphere.
We analyze landslides on Ceres using several quantitative approaches to constrain the composition and structure of the top few kilometers of Ceres' crust. We focus on a subset of archetypal ...landslides classified morphologically as thick, steep‐snouted “type 1” (T1) flows and thin spatulate “type 2” (T2) flows (Schmidt et al., 2017, https://doi.org/10.1038/ngeo2936) to explore the landslides' mechanical properties. Our results confirm earlier observations showing that T1 landslides are typically found poleward of 70° latitude and T2 mostly equatorward of 70° latitude. Measurements of landslide drop height and runout length imply effective friction coefficients lower than common friction coefficients in any of Ceres' identified or suggested non‐ice surface materials, including saturated clays. Our measurements of the volume and area of landslide scars suggest that T1 landslides can fail to greater depths than T2 for a given scar area, consistent with depth‐limited failure in T2 landslides. These results are consistent with a layer of lower shear strength material overlying a stronger layer in Ceres' outer shell at low to middle latitudes and a single layer without an overlying weak layer at polar latitudes. Combining these observations with known constraints on Ceres' near‐surface composition, we propose that Ceres' crust at low to middle latitudes consists of a topmost layer with an ice content in excess of the spectral and elemental detection depths, thins out at high latitudes, and overlies a stronger and more ice‐rich layer.
Plan Language Summary
We use landslides on Ceres to explore the possible ice content and distribution in the upper few kilometers of Ceres. The landslides used here are a subset of the best examples of the main types of landslides identified in earlier work. We confirm that type 1 landslides are only common poleward of 70° latitude and type 2 landslides are commonly equatorward of 70° latitude. Friction coefficients estimated from the landslide drop height and runout length span a range suggestive of ice. Volume and area measurements of the landslide failure scar are consistent with a weak layer overlying a stronger layer at latitudes where type 2 landslides are common and a single layer in the case of type 1 landslides, located primarily in polar latitudes. We propose that the weak layer suggested at middle and low latitudes thins out at the poles and that the stronger layer has higher ice content.
Key Points
Landslide types 1 and 2 mobilities are consistent with cold ice and warm ice respectively, with significant overlap
Type 2 landslides are consistent with a layer of weaker shear strength overlying a stronger one, which we suggest thins out by 70° latitude
We propose the low shear strength layer contains 3–19 vol% ice with the underlying layer composed of 24–40 vol% ice
•PI3V strains can be typed using molecular tests into types A, B, and C.•Commercial MLV vaccines with PI3V strains are type A.•PI3V type C is antigenic different from type A.•PI3V strains from cattle ...with BRD signs and recently vaccinated with MLV type A strains may have type B or C strains.•Cattle with BRD signs may have type A, B, or C strains in tissues or swabs.
This study investigated the genetic and antigenic characterization of parainfluenza-3 virus (PI3V) of cattle. Using molecular tests including real time PCR and viral genome sequencing, PI3V strains could be separated into PI3V types, including PI3V A, PI3V B, and PI3V C. Isolates from cattle with bovine respiratory disease clinical signs and commercial vaccines in the U.S. with MLV PI3V were typed using these molecular tests. All the MLV vaccine strains tested were PI3V A. In most cases PI3V field strains from calves receiving MLV vaccines were types heterologous to the vaccine type A. Also antigenic differences were noted as PI3V C strains had lower antibody levels than PI3V A in serums from cattle receiving MLV PI3V A vaccines. This study further demonstrates there is genetic variability of U.S. PI3V strains and also antigenic variability. In addition, isolates from cattle with BRD signs and receiving MLV vaccines may have heterologous types to the vaccines, and molecular tests should be performed to differentiate field from vaccine strains. Potentially the efficacy of current PI3V A vaccines should be evaluated with other types such a PI3V B and PI3V C.
Ice-giant-sized planets are the most common type of observed exoplanet, yet the two ice giants in our own solar system (Uranus and Neptune) are the least explored class of planet, having only been ...observed through ground-based observations and a single flyby each by Voyager 2 approximately 30 years ago. These single flybys were unable to characterize the spatial and temporal variability in ice giant magnetospheres, some of the most odd and intriguing magnetospheres in the solar system. They also offered only limited constraints on the internal structure of ice giants; understanding the internal structure of a planet is important for understanding its formation and evolution. The most recent planetary science Decadal Survey by the U.S. National Academy of Sciences, “Vision and Voyages for Planetary Science in the Decade 2013–2022,” identified the ice giant Uranus as the third highest priority for a Flagship mission in the decade 2013–2022. However, in the event that NASA or another space agency is unable to fly a Flagship-class mission to an ice giant in the next decade, this paper presents a mission concept for a focused, lower cost Uranus orbiter called OCEANUS (Origins and Composition of the Exoplanet Analog Uranus System). OCEANUS would increase our understanding of the interior structure of Uranus, its magnetosphere, and how its magnetic field is generated. These goals could be achieved with just a magnetometer and the spacecraft's radio system. This study shows that several of the objectives outlined by the Decadal Survey, including one of the two identified as highest priority, are within reach for a New-Frontiers-class mission.
•OCEANUS would be a New-Frontiers-class Uranus orbiter.•It would address 4 of the Decadal Survey objectives for a Uranus Flagship mission.•It would investigate Uranus' interior structure, magnetic field, and magnetosphere.
Telescopic observations have detected an exosphere around Ceres, composed of either water vapor or its photolytic products. Proposed mechanisms for its formation include sublimation or sputtering ...from solar energetic particles of buried ice, surface ice, or an optically thin seasonal polar cap. We estimate the amount of water vapor produced by known exposures of water ice, detected in Dawn spacecraft image and spectral data and by ice exposures from subresolution impact craters. We use thermal and sublimation modeling to take into account slope, orientation, and, in the case of water ice within craters, shadowing due to crater walls. We use a Monte Carlo approach to calculate the number of ice‐exposing impacts, where they occur on Ceres' surface, and how long the ice within the impact crater remains bright (e.g., less than one monolayer of sublimation lag). We find that the observed water ice patches on Ceres could account for ~0.06 kg/s of water vapor to (with Oxo crater as the main contributor) and that ice‐exposing impacts that remain bright in appearance after one Ceres year supply 0.08–0.56 kg/s of vapor, depending on the regolith volume fraction of the ice. While water ice has not been detected to date at Occator crater, if it were present we find that Occator is unlikely to be a major contributor of vapor. We find a typical background water vapor production rate from all of Ceres, combining surface and buried ice, of about a few tenths of a kilogram per second.
Plain Language Summary
Ceres, the closest dwarf planet to the Sun, may be periodically surrounded with water vapor. This water vapor could be coming from water ice, either exposed at the surface or buried, undergoing temperature changes during Ceres' day and year. Vapor could also be released from ice that is bombarded by solar energetic particles. In this paper, we calculate how much water vapor could be produced from ice currently exposed on the surface of Ceres due to changes in temperature. We calculate the water vapor produced from observed surface water ice patches identified in Dawn spacecraft mission data. We also calculate water vapor produced from likely water ice patches that are exposed to space after a new impact crater forms but are too small to be seen by the Dawn spacecraft's instruments. We find that from these sources plus water vapor produced from buried water ice tables (calculated in other papers), about a few tenths of a kilogram per second of water vapor is likely to be escaping Ceres at the present day.
Key Points
Observed exposed water ice patches on Ceres can contribute a few 10s of g/s of water vapor to the exosphere
Subresolution impact craters can generate new surface water ice patches that increase the total water vapor production
Modeled vapor production from both surface and buried ice suggests a lower typical rate than previously inferred by telescopic studies
Interactions between aboveground and belowground organisms are important drivers of plant growth and performance in natural ecosystems. Making practical use of such above-belowground biotic ...interactions offers important opportunities for enhancing the sustainability of agriculture, as it could favor crop growth, nutrient supply, and defense against biotic and abiotic stresses. However, the operation of above- and belowground organisms at different spatial and temporal scales provides important challenges for application in agriculture. Aboveground organisms, such as herbivores and pollinators, operate at spatial scales that exceed individual fields and are highly variable in abundance within growing seasons. In contrast, pathogenic, symbiotic, and decomposer soil biota operate at more localized spatial scales from individual plants to patches of square meters, however, they generate legacy effects on plant performance that may last from single to multiple years. The challenge is to promote pollinators and suppress pests at the landscape and field scale, while creating positive legacy effects of local plant-soil interactions for next generations of plants. Here, we explore the possibilities to improve utilization of above-belowground interactions in agro-ecosystems by considering spatio-temporal scales at which aboveground and belowground organisms operate. We identified that successful integration of above-belowground biotic interactions initially requires developing crop rotations and intercropping systems that create positive local soil legacy effects for neighboring as well subsequent crops. These configurations may then be used as building blocks to design landscapes that accommodate beneficial aboveground communities with respect to their required resources. For successful adoption of above-belowground interactions in agriculture there is a need for context-specific solutions, as well as sound socio-economic embedding.
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