33 research outputs found

    The Completeness and Unity of Between the Acts

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    Tracing the Genetic Footprints of the Redbelly Yellowtail Fusilier, Caesio Cuning, Across Multiple Spatial and Evolutionary Scales

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    Overfishing is one of the most pervasive threats to coral reef ecosystems, and management of these multi-species resources is hampered by limited species-specific population level information. The reefs in the western tropical Pacific Ocean, including the Coral Triangle, are the most bio-diverse in the world. Home to more than 400 million people, this region contains some of the most threatened coral reef ecosystems. Presented here is the first comprehensive analysis of the genetic structure of Caesio cuning, planktivorous fish inhabiting reefs in the Coral Triangle and western Pacific Ocean. Data from both classical Sanger and next-generation sequencing were analyzed across multiple spatial scales to test hypotheses regarding the biogeography, ecology, and population connectivity of this important food fish. Across the Coral Triangle, mitochondrial DNA sequencing was used to examine broad-scale genetic patterns from 33 locations. Results show the presence of two clades found on either side of the Sunda Shelf, a biogeographic pattern attributed to vicariant isolation during low sea level stands during the Pleistocene Epoch. No evidence for isolation-by-distance across the sampling region was found, however, within the clade associated with the Pacific Ocean, AMOVA and BARRIER analyses indicate significant genetic differences between central Indonesia and the Philippines relative to eastern Indonesia. Restriction site-associated DNA (RAD) sequencing data from five sites along the Kuroshio Current were used to examine fine-scale gene flow from the core to the northern limit of the species range. Results indicate that C. cuning in this region conform to the predictions of the central-peripheral population model described by Mayr (1963). Edge effects were found in peripheral populations including decreasing effective sample size, increased relatedness, and disjunct peripheral populations. Finally, since management of reef fish resources occurs at the country-level, RAD sequencing data from seven sites were used to examine fine-scale patterns of population structure within the Philippines. Results suggest that C. cuning from Palawan are genetically distinct from all other sites in the north, central, and eastern Philippines. Excluding Palawan, no isolation-by-distance was found despite significant genetic structure between many sites, indicating that gene flow within the Philippines is largely impacted by regional oceanographic features

    A Translational Polarization Rotator

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    We explore a free-space polarization modulator in which a variable phase introduction between right- and left-handed circular polarization components is used to rotate the linear polarization of the outgoing beam relative to that of the incoming beam. In this device, the polarization states are separated by a circular polarizer that consists of a quarter-wave plate in combination with a wire grid. A movable mirror is positioned behind and parallel to the circular polarizer. As the polarizer-mirror distance is separated, an incident liear polarization will be rotated through an angle that is proportional to the introduced phase delay. We demonstrate a prototype device that modulates Stokes Q and U over a 20% bandwidth

    Pronounced Genetic Structure in a Highly Mobile Coral Reef Fish, Caesio Cuning, in the Coral Triangle

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    The redbelly yellowtail fusilier, Caesio cuning, has a tropical Indo-West Pacific range that straddles the Coral Triangle, a region of dynamic geological history and the highest marine biodiversity on the planet. Previous genetic studies in the Coral Triangle indicate the presence of regional limits to connectivity across this region. However, these have focused almost exclusively on benthic reef dwelling species. Schooling, reef-associated fusiliers (Perciformes: Caesionidae) account for a sizable portion of the annual reef catch in the Coral Triangle, yet to date, there have been no in depth studies on the population structure of fusiliers or other mid-water, reef-associated planktivores across this region. We evaluated the genetic population structure of C. cuning using a 382bp segment of the mitochondrial control region amplified from over 620 fish sampled from 33 localities across the Philippines and Indonesia. Phylogeographic analysis showed that individuals sampled from sites in western Sumatra belong to a distinct Indian-Ocean lineage, resulting in pronounced regional structure between western Sumatra and the rest of the Coral Triangle (ΦCT = 0.4796, p \u3c 0.0043). We measured additional significant population structure between central Southeast Asia and eastern Indonesia (ΦCT = 0.0450, 36 p \u3c 0.0002). These data in conjunction with spatial analyses indicate that there are two major lineages of C. cuning and at least three distinct management units across the region. The location of genetic breaks as well as the distribution of divergent haplotypes across our sampling range suggests that current oceanographic patterns could be contributing to observed patterns of structure

    Pronounced Genetic Structure in a Highly Mobile Coral Reef Fish, Caesio cuning, in the Coral Triangle

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    The redbelly yellowtail fusilier Caesio cuning has a tropical Indo-West Pacific range that straddles the Coral Triangle, a region of dynamic geological history and the highest marine biodiversity on the planet. Previous genetic studies in the Coral Triangle indicate the presence of multiple limits to connectivity. However, these studies have focused almost exclusively on benthic, reef-dwelling species. Schooling, reef-associated fusiliers (Perciformes: Caesionidae) account for a sizable portion of the annual reef catch in the Coral Triangle, yet to date, there have been no indepth studies on the population structure of fusiliers or other mid-water, reef-associated planktivores across this region. We evaluated the genetic population structure of C. cuning using a 382 bp segment of the mitochondrial control region amplified from over 620 fish sampled from 33 localities across the Philippines and Indonesia. Phylogeographic analysis showed that individuals sampled from sites in western Sumatra belong to a distinct Indian Ocean lineage, resulting in pronounced regional structure between western Sumatra and the rest of the Coral Triangle (φCT = 0.4796, p \u3c 0.004). We found additional significant population structure between central Southeast Asia and eastern Indonesia (φCT = 0.0450, p \u3c 0.001). These data in conjunction with spatial analyses indicate that there are 2 major lineages of C. cuning and at least 3 distinct management units across the region. The location of genetic breaks as well as the distribution of divergent haplotypes across our sampling range suggests that current oceanographic patterns could be contributing to observed patterns of structure

    Cryptic Lineages and a Population Damned to Incipient Extinction? Insights into the Genetic Structure of a Mekong River Catfish

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    An understanding of the genetic composition of populations across management boundaries is vital to developing successful strategies for sustaining biodiversity and food resources. This is especially important in ecosystems where habitat fragmentation has altered baseline patterns of gene flow, dividing natural populations into smaller sub-populations and increasing potential loss of genetic variation through genetic drift. River systems can be highly fragmented by dams built for flow regulation and hydropower. We used reduced-representation sequencing to examine genomic patterns in an exploited catfish, Hemibagrus spilopterus, in a hotspot of biodiversity and hydropower development- the Mekong River basin. Our results revealed the presence of two highly-divergent coexisting genetic lineages which may be cryptic species. Within the lineage with the greatest sample sizes, pairwise FST values, principal components analysis, and a STRUCTURE analysis all suggest that long-distance migration is not common across the Lower Mekong Basin, even in areas where flood-pulse hydrology has limited genetic divergence. In tributaries, effective population size estimates were at least an order of magnitude lower than in the Mekong mainstream indicating these populations may be more vulnerable to perturbations such as human-induced fragmentation. Fish isolated upstream of several dams in one tributary exhibited particularly low genetic diversity, high amounts of relatedness, and a level of inbreeding (GIS = 0.51) that has been associated with inbreeding depression in other outcrossing species. Our results highlight the importance of assessing genetic structure and diversity in riverine fisheries populations across proposed dam development sites for the preservation of these critically-important resources

    Spectroscopic examinations of hydro- and glaciovolcanic basaltic tuffs: Modes of alteration and relevance for Mars

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    Hydro- and glaciovolcanism are processes that have taken place on both Earth and Mars. The amount of materials produced by these processes that are present in the martian surface layer is unknown, but may be substantial. We have used Mars rover analogue analysis techniques to examine altered tuff samples collected from multiple hydrovolcanic features, tuff rings and tuff cones, in the American west and from glaciovolcanic hyaloclastite ridges in Washington state and in Iceland. Analysis methods include VNIR-SWIR reflectance, MWIR thermal emissivity, thin section petrography, XRD, XRF, and Mössbauer spectroscopy. We distinguish three main types of tuff that differ prominently in petrography and VNIR-SWIR reflectance: minimally altered sideromelane tuff, gray to brown colored smectite-bearing tuff, and highly palagonitized tuff. Differences are also observed between the tuffs associated with hydrovolcanic tuff rings and tuff cones and those forming glaciovolcanic hyaloclastite ridges. For the locations sampled, hydrovolcanic palagonite tuffs are more smectite and zeolite rich while the palagonitized hyaloclastites from the sampled sites are largely devoid of zeolites and relatively lacking in smectites as well. The gray to brown colored tuffs are only observed in the hydrovolcanic deposits and appear to represent a distinct alteration pathway, with formation of smectites without associated palagonite formation. This is attributed to lower temperatures and possibly longer time scale alteration. Altered hydro- or glaciovolcanic materials might be recognized on the surface of Mars with rover-based instrumentation based on the results of this study

    Analysis of United States Air Forces Central government purchase card reachback viability

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    Joint Applied Project[Administration]This project investigates the viability of performing United States Air Forces Central (USAFCENT) government purchase card (GPC) purchases by utilizing reachback services. The study analyzed FY 2011 data to include the number of deployed contingency contracting officers (CCOs), GPC actions, and total contract actions at each Expeditionary Contracting Squadron. Using this data, models were developed that showed potential reductions in deployed CCOs if GPC actions were sent from USAFCENT area of responsibility to a stateside reachback cell. The study provides recommendations based on the potential reductions of deployed CCOs. One such recommendation is to stand up a test reachback cell. This cell will employ the recommended number of personnel developed by the models in this project..http://archive.org/details/analysisofunited1094510718US Air Force (USAF) author

    Investigating the Mineralogy and Morphology of Subglacial Volcanoes on Earth and Mars

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    In this dissertation, we have examined mineral assemblages and geomorphologic features in the Sisyphi Planum region of Mars, as well as examined the mineral assemblage of palagonite in Iceland. Chapter 2 is focused on the mineral assemblages detected on possible glaciovolcanic edifices in the Sisyphi Planum region of Mars. Minerals were identified utilizing visible/nearinfrared orbital spectra from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM). Analysis of eleven CRISM images located on the volcanic edifices revealed three distinct spectral classes in the region which are interpreted to be: gypsum-dominated, smectitezeolite- iron oxide-dominated (possibly palagonite), and polyhydrated sulfate-dominated material. The possible palagonite detections on the volcanic edifices, the geomorphology of the region, and the analogous terrestrial mineralogy of subglacial eruptions strongly suggests the formation of these minerals during subglacial eruptions or associated hydrothermal systems. This implies that thick water ice sheets were present in this region in the late Noachian or early Hesperian, and that the subglacial hydrothermal systems could have supported habitable environments with excellent biosignature preservation potential. Chapter 3 is focused on evaluating the variability of the composition and crystallinity of palagonite on Earth in order to inform efforts to identify it on Mars. We hypothesized that variability in palagonite composition and crystallinity could occur due to differences in environmental conditions during formation. Palagonite samples were collected in Iceland at subglacial volcanic sites around Reykjavík in the Western Volcanic Zone, on the southern coast in the Eastern Volcanic Zone, and from the Herðubreið tuya and Askja volcano in the Northern Volcanic Zone. Visible/near-infrared reflectance spectroscopy, thermal-infrared emission spectroscopy, and quantitative XRD were used to assess the bulk mineralogy, crystallinity, and clay composition of all samples. Results show the sampled palagonites contain partially devitrified glass, unaltered glass, and secondary minerals including clay minerals, poorly crystalline ferric oxides, and zeolites. However, one sample (SCoast01) shows a vastly different mineral assemblage in all sample techniques, including well-crystalline Fe/Mg-clays as opposed to the poorly-crystalline Al-clays observed in our other samples. Based on previous studies of subaqueous palagonites and the location this sample was collected from, we hypothesize that the SCoast01 sample was formed in a submarine environment rather than subglacial. This suggests that it may be possible to differentiate submarine vs. subglacial palagonite on Earth based on composition and from remote sensing observations on Mars. Chapter 4 is a geomorphologic study of the Sisyphi Planum region of Mars where we identified and classified the tops of the Sisyphi Montes as well as geomorphologically mapped the Sisyphi Planum region. Here, we address an overarching question: What is the relationship between the Sisyphi Montes and the ice in this region? To do this, we identified 106 edifices in the region and classified them into five categories: 1) flat topped, 2) rounded tops, 3) sharp peaks, 4) cratered peaks, and 5) height less than 300 meters – a “catch-all” category for all features below the specified height, which exhibit less distinctive morphologies in MOLA topography
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