A molecular phylogenetic analysis of strombid gastropod morphological diversity

The shells of strombid gastropods show a wide variety of forms, ranging from small and fusiform to large and elaborately ornamented with a strongly flared outer lip. Here, we present the first species-level molecular phylogeny for strombids and use the resulting phylogenetic framework to explore relationships between species richness and morphological diversity. We use portions of one nuclear (325 bp of histone H3) and one mitochondrial (640 bp of cytochrome oxidase I, COI) gene to infer relationships within the two most species-rich genera in the Strombidae: Strombus and Lambis. We include 32 species of Strombus, representing 10 of 11 extant subgenera, and 3 of the 9 species of Lambis, representing 2 of 3 extant subgenera. Maximum likelihood and Bayesian analyses of COI and of H3 and COI combined suggest Lambis is nested within a paraphyletic Strombus. Eastern Pacific and western Atlantic species of Strombus form a relatively recent monophyletic radiation within an older, paraphyletic Indo-West Pacific grade. Morphological diversity of subclades scales positively with species richness but does not show evidence of strong phylogenetic constraints. © 2006 Elsevier Inc. All rights reserved

Baltistan in 1891 and 1912: The Smithsonian’s Baltistan Collections from two Expeditions by American Naturalist William Louis Abbott

This paper introduces an important group of unpublished ethnographic and archival materials deriving from two expeditions to Baltistan by the American naturalist collector William Louis Abbott (1860-1935), the first in 1891-1892 and the second in 1912. This paper presents Abbott as a particular type of scientific explorer (the American ―naturalist‖), re-assesses the importance of this region to him and to Smithsonian scientists of the time, and publishes here for the first time a record of his observations and ethnographic collections from Baltistan. These ethnographic collections, alongside archival correspondence and field notes, form a little-known resource at the Smithsonian Institution, Washington, D.C. This paper also summarizes the role Abbott and other ―naturalist‖ collectors of this period played within the history of anthropology and museums, and points to some of the many new 21st-century uses of ―legacy‖ collections and records of the kind he assembled about this region. Present-day museums often reach out to the descendants of peoples among whom such historic collections were made, inviting them to help interpret and display these artifacts. Museum collections can also thereby help preserve endangered cultural traditions

Pilot Visual Detection of Small Unmanned Aircraft Systems (sUAS) Equipped with Strobe Lighting

When operating under Visual Flight Rules, pilots primarily rely on visual scanning to avoid other aircraft and airborne collision threats. Records from the Federal Aviation Administration indicate that near encounters with unmanned aircraft are on the rise, reaching 1,761 reported unmanned aircraft system (UAS) sightings or near-misses in 2016. This study sought to assess the effectiveness of pilot visual detection of UAS platforms that were equipped with strobe lighting. A sample of 10 pilots flew a general aviation aircraft on a scripted series of five intercepts with a small UAS (sUAS) that was equipped with strobe lighting. Participants were asked to indicate when they visually detected the unmanned aircraft. Geolocation information for both the aircraft and sUAS platform was compared to assess visibility distance. Findings were used to evaluate the efficacy of daytime strobe lighting as a method to enhance pilot sUAS detection, visibility, and collision avoidance. Participants detected the unmanned aircraft during 7.7% of the intercepts. Due to a lack of data points, the authors were unable to conclusively determine if strobe lighting improved UAS visual detection. The authors recommend further research to explore the effectiveness of using sUAS-mounted strobe lights for nighttime visual detection

Detecting and Assessing Collision Potential of Aircraft and Small Unmanned Aircraft Systems (sUAS) by Visual Observers

Visual observers are used to assist the Remote Pilot with maintaining sight of the unmanned aircraft as well as scanning the surrounding airspace for potential collision hazards. The purpose of this study was to examine the effectiveness of visual observers in detecting an intruding general aviation aircraft approaching the small unmanned aircraft system (sUAS) operations area. The study sought to determine the effectiveness of sUAS visual observers in detecting a general aviation aircraft collision hazard with a sUAS. Ten participants were asked to perform visual observer duties in support of a sUAS operation. Participants were asked to indicate when they were able to hear and see an aircraft that conducted a scripted series of close intercepts with a sUAS. Additionally, researchers assessed each visual observer’s ability to accurately judge the closure rate of the aircraft, by estimating the duration from initial sighting until the aircraft would intercept the airborne sUAS platform. Geolocation data from both the aircraft and sUAS were time correlated and compared to determine estimation accuracy. Findings were used to formulate operational recommendations to improve visual observer performance in detecting and assessing intruder aircraft collision potential

Influence of Abiotic Drivers on 1-Year Seedling Survival of Six Mangrove Species in Southeast Asia

Establishment and survival of plant species in systems with dominant environmental drivers (i.e. factors that exert disproportionate control over species establishment and survival) is often thought to be dominated by one master variable. In forested wetlands such as mangroves, hydrology is typically considered the dominant limiting driver. At the same time, light is a major driver of plant community dynamics, with some of the best understood plant life-history tradeoffs related to fast growth under high-light conditions versus survival under low-light conditions. Yet light is given relatively limited consideration in mangrove research compared to other drivers. Understanding the relative importance of abiotic drivers for seedling survival is crucial for effective management and restoration of mangrove ecosystems. Despite increasing global efforts to plant mangrove propagules at elevations appropriate for the hydrologic conditions needed at early life history stages, restoration efforts report low survival of planted propagules. Although many studies have made considerable progress to characterize the abiotic limitations of mangrove propagule establishment, fewer studies have addressed multiple abiotic drivers that limit the survival of the established seedling stage. We characterized the light and inundation conditions of more than 900 naturally established mangrove seedlings and monitored the survival of more than 2,800 seedlings (including 16 species) located on a species-rich island in tropical Southeast Asia for 1 year. Our findings suggest that light has a stronger effect than hydrology on survival following seedling establishment. We provide a conceptual visualization of shifts in the drivers of mangrove survival/loss throughout ontogeny

Pilot Visual Detection of Small Unmanned Aircraft on Final Approach during Nighttime Conditions

In December 2020, the Federal Aviation Administration (FAA) announced the release of a new final rule, permitting operators of small unmanned aircraft systems (sUAS) to perform routine night operations. Public comments to the Notice of Proposed Rulemaking indicated potential safety concerns regarding a pilot’s ability to spot a low-altitude sUAS during nighttime conditions. Leveraging data from the FAA’s UAS Sighting Report Database, the research team evaluated the significance of aircraft encounters with UAS at night. Researchers conducted an inflight experiment in which 10 pilots performed an instrument approach to airport during nighttime conditions in which a multi-rotor sUAS presented a potential collision hazard. The sUAS was equipped with lighting visible for 3 miles with a sufficient flash rate to avoid a collision, as specified by the new regulation. Participants performed five approaches, with the sUAS flying different scripted encounter profiles. Participants were asked to indicate when they visually spotted the sUAS, with sighting data recorded via an onboard observer. Geolocation information from both the aircraft and sUAS were compared at the time of each reported sighting to assess visibility distance and orientation. The sUAS was successfully spotted during 30 percent (n = 12) of the testing passes. Hovering sUAS were spotted at the same rate as moving sUAS, however, sUAS in motion were spotted at a much greater range. Researchers noted disproportionately higher spotting rates occurred when the sUAS was oriented on the starboard side of the aircraft vs. the port side. It is believed that airport lighting systems may have obscured or otherwise camouflaged portside sUAS encounters. When asked to estimate distance to an encountered sUAS, most participants underestimated, perceiving the sUAS to be much closer than reality. Additionally, the researchers assessed the potential for the participants to initiate evasive maneuvers, based on the distance and closure rate of the aircraft and sUAS at the time of sighting. Based on the FAA’s Aircraft Identification and Reaction Time Chart, collision avoidance would only have been successful during 15 percent of encounters (n = 6). The research team recommends Remote Pilots employ vigilant traffic awareness during nighttime operations, and leverage use of ADS-B (In) technology and monitor Common Traffic Advisory Frequencies to maintain situational awareness—particularly when operating in proximity to airports

Cleared to Land: Pilot Visual Detection of Small Unmanned Aircraft During Final Approach

Sighting reports of unmanned aircraft systems (UAS) by pilots, air traffic controllers, and other aviation stakeholders have continued to rise since the Federal Aviation Administration (FAA) began tracking in 2014. In 2018, the FAA received 2,307 such reports, with 22.8% (n = 526) occurring during the final approach phase of flight. The threat of a midair collision between a manned aircraft and UAS is heightened during the final approach phase of flight, as the aircraft transitions from higher-altitude airspace to the low-altitude arena, now shared with drones. Absent UAS sense and avoid systems, pilots are forced to rely on visual senses and scanning techniques to ensure the approach path remains clear of UAS incursions. This research evaluated the effectiveness of pilot visual detection of a multirotor UAS during five approach to landing scenarios in which an unmanned aircraft created an incursion into the approach path. During the scripted approach scenarios, the UAS either remained stationary or maneuvered laterally. Both aircraft and UAS were separated by established vertical safety margins and protocols to avoid an actual collision. Overall, participants detected the UAS during 30% of the approaches. The static UAS was only detected during 13.6% of the approaches, at a mean range of 647 ft. The detection rate improved to 50% when the drone was in motion, with a mean detection range of 1,593 ft. Vector data was calculated to determine the detection angle of UAS sightings, with the majority of successful detections occurring within 5˚ laterally and 10˚ vertically of center. Qualitative comments were solicited from the participants and evaluated for trends. Forty percent of the participants indicated that moving UAS are easier to spot. Other trends related to UAS contrast, object misidentification, and detection aspect angle were also identified by the participants. The authors emphasized that based on the recorded detection distance, pilots would only have a limited margin of error to successfully execute evasive maneuvers, based on the FAA’s Recommended Minimum Reaction Time Required for Evasion criteria. Full-text will be available October 30, 2019 at approximately 10:00 AM Eastern

Citizen science can add value to Phytophthora monitoring: five case studies from western North America

Phytophthora species are plant pathogens responsible for many notable biological invasions in agricultural, forests, and natural ecosystems. Detection and monitoring for invasive introductions of Phytophthora spp. is time and resource intensive. Development of citizen science detection and monitoring programs can aid in these efforts focused on reducing Phythophthora impacts. There are multiple methods for monitoring and detecting Phytophthora invasions suitable for citizen science approaches such as, leaf sampling, stream baiting or soil collections. Here we summarize five active projects in western North America where citizen scientists are aiding the monitoring and research efforts surrounding Phytophthora species and their impacts. Projects varied in scope, scale, methods, and capacity, but each project increased citizen scientists’ abilities for surveillance and advanced detection or knowledge of Phytophthora species. Some projects were integrated with school programs, others involved hands-on training with small groups, and another approach invited mass participation from interested citizens. Overall, all projects had positive outcomes multiplied across education, monitoring, and research. Together these case studies demonstrate how citizen scientists can amplify surveillance efforts, advance baseline knowledge, and reduce the impacts of biological invasions

Diversity and evolution of 11 innate immune genes in Bos taurus taurus and Bos taurus indicus cattle

The Toll-like receptor (TLR) and peptidoglycan recognition protein 1 (PGLYRP1) genes play key roles in the innate immune systems of mammals. While the TLRs recognize a variety of invading pathogens and induce innate immune responses, PGLYRP1 is directly microbicidal. We used custom allele-specific assays to genotype and validate 220 diallelic variants, including 54 nonsynonymous SNPs in 11 bovine innate immune genes (TLR1-TLR10, PGLYRP1) for 37 cattle breeds. Bayesian haplotype reconstructions and median joining networks revealed haplotype sharing between Bos taurus taurus and Bos taurus indicus breeds at every locus, and we were unable to differentiate between the specialized B. t. taurus beef and dairy breeds, despite an average polymorphism density of one locus per 219 bp. Ninety-nine tagSNPs and one tag insertion-deletion polymorphism were sufficient to predict 100% of the variation at all 11 innate immune loci in both subspecies and their hybrids, whereas 58 tagSNPs captured 100% of the variation at 172 loci in B. t. taurus. PolyPhen and SIFT analyses of nonsynonymous SNPs encoding amino acid replacements indicated that the majority of these substitutions were benign, but up to 31% were expected to potentially impact protein function. Several diversity-based tests provided support for strong purifying selection acting on TLR10 in B. t. taurus cattle. These results will broadly impact efforts related to bovine translational genomics