4,558 research outputs found
Bacterial community profiles and Vibrio parahaemolyticus abundance in individual oysters and their association with estuarine ecology
Oysters naturally harbor the human gastric pathogen Vibrio parahaemolyticus, but the nature of this association is unknown. Because microbial interactions could influence the accumulation of V. parahaemolyticus in oysters, we investigated the composition of the microbiome in water and oysters at two ecologically unique sites in the Great Bay Estuary, New Hampshire using 16s rRNA profiling. We then evaluated correlations between bacteria inhabiting the oyster with V. parahaemolyticus abundance quantified using a most probable number (MPN) analysis. Even though oysters filter-feed, their microbiomes were not a direct snapshot of the bacterial community in overlaying water, suggesting they selectively accumulate some bacterial phyla. The microbiome of individual oysters harvested more centrally in the bay were relatively more similar to each other and had fewer unique phylotypes, but overall more taxonomic and metabolic diversity, than the microbiomes from tributary-harvested oysters that were individually more variable with lower taxonomic and metabolic diversity. Oysters harvested from the same location varied in V. parahaemolyticus abundance, with the highest abundance oysters collected from one location. This study, which to our knowledge is the first of its kind to evaluate associations of V. parahaemolyticus abundance with members of individual oyster microbiomes, implies that sufficient sampling and depth of sequencing may reveal microbiome members that could impact V. parahaemolyticus abundance
Factors That Impact Service Delivery to Individuals Living With HIV/AIDS in Rural Northeastern Texas
This study surveyed participants in focus groups to identify factors that affect individuals living with HIV/AIDS in rural northeastern Texas. The average age of the respondents was 45.44. Participants included a diverse group of American Europeans, Hispanics/Latinos, and African Americans. Although results are inconclusive, other studies have supported similar results regarding factors that impact treatment and services (Zuniga, Buchanan, & Chakravorty, 2005). Some of the factors include lack of financial resources for the consumer, stigma and discrimination, and lack of understanding on the part of the consumer and the community. More studies in rural areas serving people living with HIV/AIDS (PLHA) are needed to begin the work towards breaking down barriers to provide healthier environments and achieving social and economic justice
Extended Photometry for the DEEP2 Galaxy Redshift Survey: A Testbed for Photometric Redshift Experiments
This paper describes a new catalog that supplements the existing DEEP2 Galaxy
Redshift Survey photometric and spectroscopic catalogs with ugriz photometry
from two other surveys; the Canada-France-Hawaii Legacy Survey (CFHTLS) and the
Sloan Digital Sky Survey (SDSS). Each catalog is cross-matched by position on
the sky in order to assign ugriz photometry to objects in the DEEP2 catalogs.
We have recalibrated the CFHTLS photometry where it overlaps DEEP2 in order to
provide a more uniform dataset. We have also used this improved photometry to
predict DEEP2 BRI photometry in regions where only poorer measurements were
available previously. In addition, we have included improved astrometry tied to
SDSS rather than USNO-A2.0 for all DEEP2 objects. In total this catalog
contains ~27,000 objects with full ugriz photometry as well as robust
spectroscopic redshift measurements, 64% of which have r > 23. By combining the
secure and accurate redshifts of the DEEP2 Galaxy Redshift Survey with ugriz
photometry, we have created a catalog that can be used as an excellent testbed
for future photo-z studies, including tests of algorithms for surveys such as
LSST and DES.Comment: 12 pages, 6 figures and 5 tables. Accepted to The Astrophysical
Journal Supplement. Catalogs are publicly available at
http://deep.ps.uci.edu/DR4/photo.extended.htm
A three-dimensional orthogonal laser velocimeter for the NASA Ames 7- by 10-foot wind tunnel
A three-component dual-beam laser-velocimeter system has been designed, fabricated, and implemented in the 7-by 10-Foot Wind Tunnel at NASA Ames Research Center. The instrument utilizes optical access from both sides and the top of the test section, and is configured for uncoupled orthogonal measurements of the three Cartesian coordinates of velocity. Bragg cell optics are used to provide fringe velocity bias. Modular system design provides great flexibility in the location of sending and receiving optics to adapt to specific experimental requirements. Near-focus Schmidt-Cassegrain optic modules may be positioned for collection of forward or backward scattered light over a large solid angle, and may be clustered to further increase collection solid angle. Multimode fiber optics transmit collected light to the photomultiplier tubes for processing. Counters are used to process the photomultiplier signals and transfer the processed data digitally via buffered interface controller to the host MS-DOS computer. Considerable data reduction and graphical display programming permit on-line control of data acquisition and evaluation of the incoming data. This paper describes this system in detail and presents sample data illustrating the system's capability
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Large-effect flowering time mutations reveal conditionally adaptive paths through fitness landscapes in Arabidopsis thaliana.
Contrary to previous assumptions that most mutations are deleterious, there is increasing evidence for persistence of large-effect mutations in natural populations. A possible explanation for these observations is that mutant phenotypes and fitness may depend upon the specific environmental conditions to which a mutant is exposed. Here, we tested this hypothesis by growing large-effect flowering time mutants of Arabidopsis thaliana in multiple field sites and seasons to quantify their fitness effects in realistic natural conditions. By constructing environment-specific fitness landscapes based on flowering time and branching architecture, we observed that a subset of mutations increased fitness, but only in specific environments. These mutations increased fitness via different paths: through shifting flowering time, branching, or both. Branching was under stronger selection, but flowering time was more genetically variable, pointing to the importance of indirect selection on mutations through their pleiotropic effects on multiple phenotypes. Finally, mutations in hub genes with greater connectedness in their regulatory networks had greater effects on both phenotypes and fitness. Together, these findings indicate that large-effect mutations may persist in populations because they influence traits that are adaptive only under specific environmental conditions. Understanding their evolutionary dynamics therefore requires measuring their effects in multiple natural environments
Evaluation of Transplanted Tissue-Engineered Oral Mucosa Equivalents in Severe Combined Immunodeficient Mice
The aim of this study was to determine the optimal stage of development at which transplant human ex vivo-produced oral mucosa equivalents (EVPOMEs) in vivo. EVPOMEs were generated in a serum-free culture system, without the use of an irradiated xenogeneic feeder layer, by seeding human oral keratinocytes onto a human cadaveric dermal equivalent, AlloDerm. EVPOMEs were cultured for 4 days submerged and then for 7 or 14 days at an air-liquid interface to initiate stratification before transplantation into SCID mice. AlloDerm, without epithelium, was used as a control. Mice were killed on days 3, 10, and 21 posttransplantation. Epithelium of the transplanted EVPOMEs was evaluated with the differentiation marker keratin 10/13. Dermal microvessel ingrowth was determined by immunohistochemistry with a mouse vascular marker, lectin binding from Triticum vulgaris. The presence and stratification of the epithelium were correlated with revascularization of the underlying dermis. The microvessel density of AlloDerm without epithelium was less than that of EVPOMEs with an epithelial layer. Microvessel density of the dermis varied directly with the degree of epithelial stratification of the EVPOMEs. The EVPOMEs cultured at an air-liquid interface for 7 days had the optimal balance of neoangiogenesis and epithelial differentiation necessary for in vivo grafting.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63269/1/107632703762687645.pd
Baseline Assessment and Prioritization Framework for IVHM Integrity Assurance Enabling Capabilities
Fundamental to vehicle health management is the deployment of systems incorporating advanced technologies for predicting and detecting anomalous conditions in highly complex and integrated environments. Integrated structural integrity health monitoring, statistical algorithms for detection, estimation, prediction, and fusion, and diagnosis supporting adaptive control are examples of advanced technologies that present considerable verification and validation challenges. These systems necessitate interactions between physical and software-based systems that are highly networked with sensing and actuation subsystems, and incorporate technologies that are, in many respects, different from those employed in civil aviation today. A formidable barrier to deploying these advanced technologies in civil aviation is the lack of enabling verification and validation tools, methods, and technologies. The development of new verification and validation capabilities will not only enable the fielding of advanced vehicle health management systems, but will also provide new assurance capabilities for verification and validation of current generation aviation software which has been implicated in anomalous in-flight behavior. This paper describes the research focused on enabling capabilities for verification and validation underway within NASA s Integrated Vehicle Health Management project, discusses the state of the art of these capabilities, and includes a framework for prioritizing activities
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Transient and steady state creep response of ice I and magnesium sulfate hydrate eutectic aggregates
Using uniaxial compression creep experiments, we characterized the transient and steady state deformation behaviors of eutectic aggregates of system ice I and MgSO4 ā¢ 11H2O (MS11; meridianiite), which has significance because of its likely presence on moons of the outer solar system. Synthetic samples of eutectic liquid bulk composition, which produce eutectic colonies containing 0.35ā0.50 volume fraction MS11, were tested as functions of colony size and lamellar spacing, temperature (230ā250 K), and confining pressure (0.1 and 50 MPa) to strains ā¤ 0.2. Up to a differential stress of 6 MPa, the ice IāMS11 aggregates display an order of magnitude higher effective viscosity and higher stress sensitivity than do aggregates of pure polycrystalline ice at the same conditions. The creep data and associated microstructural observations demonstrate, however, that the aggregates are additionally more brittle than pure ice, approaching rateāindependent plasticity that includes rupture of the hydrate phase at 6ā8 MPa, depending on the scale of the microstructure. Microstructures of deformed samples reveal forms of semibrittle flow in which the hydrate phase fractures while the ice phase deforms plastically. Semibrittle flow in the icy shell of a planetary body would truncate the lithospheric strength envelope and thereby decrease the depth to the brittleāductile transition by 55% and reduce the failure limit for compressional surface features from 10 to ā¼6 MPa. A constitutive equation that includes eutectic colony boundary sliding and intracolony flow is used to describe the steady state rheology of the eutectic aggregates
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