41 results on '"Travis S"'
Search Results
2. Mercury and selenium concentrations in fishes of the Upper Colorado River Basin, southwestern United States: A retrospective assessment.
- Author
-
Natalie K Day, Travis S Schmidt, James J Roberts, Barbara C Osmundson, James J Willacker, and Collin A Eagles-Smith
- Subjects
Medicine ,Science - Abstract
Mercury (Hg) and selenium (Se) are contaminants of concern for fish in the Upper Colorado River Basin (UCRB). We explored Hg and Se in fish tissues (2,324 individuals) collected over 50 years (1962-2011) from the UCRB. Samples include native and non-native fish collected from lotic waterbodies spanning 7 major tributaries to the Colorado River. There was little variation of total mercury (THg) in fish assemblages basin-wide and only 13% (272/1959) of individual fish samples exceeded the fish health benchmark (0.27 μg THg/g ww). Most THg exceedances were observed in the White-Yampa tributary whereas the San Juan had the lowest mean THg concentration. Risks associated with THg are species specific with exceedances dominated by Colorado Pikeminnow (mean = 0.38 and standard error ± 0.08 μg THg/g ww) and Roundtail Chub (0.24 ± 0.06 μg THg/g ww). For Se, 48% (827/1720) of all individuals exceeded the fish health benchmark (5.1 μg Se/g dw). The Gunnison river had the most individual exceedances of the Se benchmark (74%) whereas the Dirty Devil had the fewest. We identified that species of management concern accumulate THg and Se to levels above risk thresholds and that fishes of the White-Yampa (THg) and Gunnison (Se) rivers are at the greatest risk in the UCRB.
- Published
- 2020
- Full Text
- View/download PDF
3. Benchmarking treewidth as a practical component of tensor network simulations.
- Author
-
Eugene F Dumitrescu, Allison L Fisher, Timothy D Goodrich, Travis S Humble, Blair D Sullivan, and Andrew L Wright
- Subjects
Medicine ,Science - Abstract
Tensor networks are powerful factorization techniques which reduce resource requirements for numerically simulating principal quantum many-body systems and algorithms. The computational complexity of a tensor network simulation depends on the tensor ranks and the order in which they are contracted. Unfortunately, computing optimal contraction sequences (orderings) in general is known to be a computationally difficult (NP-complete) task. In 2005, Markov and Shi showed that optimal contraction sequences correspond to optimal (minimum width) tree decompositions of a tensor network's line graph, relating the contraction sequence problem to a rich literature in structural graph theory. While treewidth-based methods have largely been ignored in favor of dataset-specific algorithms in the prior tensor networks literature, we demonstrate their practical relevance for problems arising from two distinct methods used in quantum simulation: multi-scale entanglement renormalization ansatz (MERA) datasets and quantum circuits generated by the quantum approximate optimization algorithm (QAOA). We exhibit multiple regimes where treewidth-based algorithms outperform domain-specific algorithms, while demonstrating that the optimal choice of algorithm has a complex dependence on the network density, expected contraction complexity, and user run time requirements. We further provide an open source software framework designed with an emphasis on accessibility and extendability, enabling replicable experimental evaluations and future exploration of competing methods by practitioners.
- Published
- 2018
- Full Text
- View/download PDF
4. Lemur species-specific metapopulation responses to habitat loss and fragmentation.
- Author
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Travis S Steffens and Shawn M Lehman
- Subjects
Medicine ,Science - Abstract
Determining what factors affect species occurrence is vital to the study of primate biogeography. We investigated the metapopulation dynamics of a lemur community consisting of eight species (Avahi occidentalis, Propithecus coquereli, Microcebus murinus, Microcebus ravelobensis, Lepilemur edwardsi, Cheirogaleus medius, Eulemur mongoz, and Eulemur fulvus) within fragmented tropical dry deciduous forest habitat in Ankarafantsika National Park, Madagascar. We measured fragment size and isolation of 42 fragments of forest ranging in size from 0.23 to 117.7 ha adjacent to continuous forest. Between June and November 2011, we conducted 1218 surveys and observed six of eight lemur species (M. murinus, M. ravelobensis, C. medius, E. fulvus, P. coquereli, and L. edwardsi) in the 42 fragments. We applied among patch incidence function models (IFMs) with various measures of dispersal and a mainland-island IFM to lemur species occurrence, with the aim of answering the following questions: 1) Do lemur species in dry deciduous forest fragments form metapopulations? 2) What are the separate effects of area (extinction risk) and connectivity/isolation (colonization potential) within a lemur metapopulation? 3) Within simulated metapopulations over time, how do area and connectivity/isolation affect occurrence? and 4) What are the conservation implications of our findings? We found that M. murinus formed either a mainland-island or an among patch metapopulation, M. ravelobensis formed a mainland-island metapopulation, C. medius and E. fulvus formed among patch metapopulations, and neither P. coquereli or L. edwardsi formed a metapopulation. Metapopulation dynamics and simulations suggest that area was a more consistent positive factor determining lemur species occurrence than fragment isolation and is crucial to the maintenance of lemur populations within this fragmented landscape. Using a metapopulation approach to lemur biogeography is critical for understanding how lemur species respond to forest loss and fragmentation.
- Published
- 2018
- Full Text
- View/download PDF
5. A syndemic approach to assess the effect of substance use and social disparities on the evolution of HIV/HCV infections in British Columbia.
- Author
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Zahid Ahmad Butt, Nabin Shrestha, Stanley Wong, Margot Kuo, Dionne Gesink, Mark Gilbert, Jason Wong, Amanda Yu, Maria Alvarez, Hasina Samji, Jane A Buxton, James C Johnston, Victoria J Cook, David Roth, Theodora Consolacion, Michelle Murti, Travis S Hottes, Gina Ogilvie, Robert Balshaw, Mark W Tyndall, Mel Krajden, Naveed Z Janjua, and BC Hepatitis Testers Cohort
- Subjects
Medicine ,Science - Abstract
Co-occurrence of social conditions and infections may affect HIV/HCV disease risk and progression. We examined the changes in relationship of these social conditions and infections on HIV and hepatitis C virus (HCV) infections over time in British Columbia during 1990-2013.The BC Hepatitis Testers Cohort (BC-HTC) includes ~1.5 million individuals tested for HIV or HCV, or reported as a case of HCV, HIV, HBV, or tuberculosis linked to administrative healthcare databases. We classified HCV and HIV infection status into five combinations: HIV-/HCV-, HIV+monoinfected, HIV-/HCV+seroconverters, HIV-/HCV+prevalent, and HIV+/HCV+.Of 1.37 million eligible individuals, 4.1% were HIV-/HCV+prevalent, 0.5% HIV+monoinfected, 0.3% HIV+/HCV+ co-infected and 0.5% HIV-/HCV+seroconverters. Overall, HIV+monoinfected individuals lived in urban areas (92%), had low injection drug use (IDU) (4%), problematic alcohol use (4%) and were materially more privileged than other groups. HIV+/HCV+ co-infected and HIV-/HCV+seroconverters were materially most deprived (37%, 32%), had higher IDU (28%, 49%), problematic alcohol use (14%, 17%) and major mental illnesses (12%, 21%). IDU, opioid substitution therapy, and material deprivation increased in HIV-/HCV+seroconverters over time. In multivariable multinomial regression models, over time, the odds of IDU declined among HIV-/HCV+prevalent and HIV+monoinfected individuals but not in HIV-/HCV+seroconverters. Declines in odds of problematic alcohol use were observed in HIV-/HCV+seroconverters and coinfected individuals over time.These results highlight need for designing prevention, care and support services for HIV and HCV infected populations based on the evolving syndemics of infections and social conditions which vary across groups.
- Published
- 2017
- Full Text
- View/download PDF
6. Thermal regimes of Rocky Mountain lakes warm with climate change.
- Author
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James J Roberts, Kurt D Fausch, Travis S Schmidt, and David M Walters
- Subjects
Medicine ,Science - Abstract
Anthropogenic climate change is causing a wide range of stresses in aquatic ecosystems, primarily through warming thermal conditions. Lakes, in response to these changes, are experiencing increases in both summer temperatures and ice-free days. We used continuous records of lake surface temperature and air temperature to create statistical models of daily mean lake surface temperature to assess thermal changes in mountain lakes. These models were combined with downscaled climate projections to predict future thermal conditions for 27 high-elevation lakes in the southern Rocky Mountains. The models predict a 0.25°C·decade-1 increase in mean annual lake surface temperature through the 2080s, which is greater than warming rates of streams in this region. Most striking is that on average, ice-free days are predicted to increase by 5.9 days ·decade-1, and summer mean lake surface temperature is predicted to increase by 0.47°C·decade-1. Both could profoundly alter the length of the growing season and potentially change the structure and function of mountain lake ecosystems. These results highlight the changes expected of mountain lakes and stress the importance of incorporating climate-related adaptive strategies in the development of resource management plans.
- Published
- 2017
- Full Text
- View/download PDF
7. Deconvolution of Complex 1D NMR Spectra Using Objective Model Selection.
- Author
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Travis S Hughes, Henry D Wilson, Ian Mitchelle S de Vera, and Douglas J Kojetin
- Subjects
Medicine ,Science - Abstract
Fluorine (19F) NMR has emerged as a useful tool for characterization of slow dynamics in 19F-labeled proteins. One-dimensional (1D) 19F NMR spectra of proteins can be broad, irregular and complex, due to exchange of probe nuclei between distinct electrostatic environments; and therefore cannot be deconvoluted and analyzed in an objective way using currently available software. We have developed a Python-based deconvolution program, decon1d, which uses Bayesian information criteria (BIC) to objectively determine which model (number of peaks) would most likely produce the experimentally obtained data. The method also allows for fitting of intermediate exchange spectra, which is not supported by current software in the absence of a specific kinetic model. In current methods, determination of the deconvolution model best supported by the data is done manually through comparison of residual error values, which can be time consuming and requires model selection by the user. In contrast, the BIC method used by decond1d provides a quantitative method for model comparison that penalizes for model complexity helping to prevent over-fitting of the data and allows identification of the most parsimonious model. The decon1d program is freely available as a downloadable Python script at the project website (https://github.com/hughests/decon1d/).
- Published
- 2015
- Full Text
- View/download PDF
8. Post-translational processing of synaptophysin in the rat retina is disrupted by diabetes.
- Author
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Travis S D'Cruz, Brittany N Weibley, Scot R Kimball, and Alistair J Barber
- Subjects
Medicine ,Science - Abstract
Synaptophysin, is an abundant presynaptic protein involved in synaptic vesicle recycling and neurotransmitter release. Previous work shows that its content is significantly reduced in the rat retina by streptozotocin (STZ)-diabetes. This study tested the hypothesis that STZ-diabetes alters synaptophysin protein turnover and glycosylation in the rat retina. Whole explant retinas from male Sprague-Dawley rats were used in this study. Rats were made diabetic by a single intraperitoneal STZ injection (65 mg/kg body weight in 10 mM sodium citrate, pH 4.5). mRNA translation was measured using a (35)S-methionine labeling assay followed by synaptophysin immunoprecipitation and autoradiography. A pulse-chase study was used to determine the depletion of newly synthesized synaptophysin. Depletion of total synaptophysin was determined after treatment with cycloheximide. Mannose rich N-glycosylated synaptophysin was detected by treating retinal lysates with endoglycosidase H followed by immunoblot analysis. Synaptophysin mRNA translation was significantly increased after 1 month (p
- Published
- 2012
- Full Text
- View/download PDF
9. Influenza vaccine effectiveness in the elderly based on administrative databases: change in immunization habit as a marker for bias.
- Author
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Travis S Hottes, Danuta M Skowronski, Brett Hiebert, Naveed Z Janjua, Leslie L Roos, Paul Van Caeseele, Barbara J Law, and Gaston De Serres
- Subjects
Medicine ,Science - Abstract
Administrative databases provide efficient methods to estimate influenza vaccine effectiveness (IVE) against severe outcomes in the elderly but are prone to intractable bias. This study returns to one of the linked population databases by which IVE against hospitalization and death in the elderly was first assessed. We explore IVE across six more recent influenza seasons, including periods before, during, and after peak activity to identify potential markers for bias.Acute respiratory hospitalization and all-cause mortality were compared between immunized/non-immunized community-dwelling seniors ≥65 years through administrative databases in Manitoba, Canada between 2000-01 and 2005-06. IVE was compared during pre-season/influenza/post-season periods through logistic regression with multivariable adjustment (age/sex/income/residence/prior influenza or pneumococcal immunization/medical visits/comorbidity), stratification based on prior influenza immunization history, and propensity scores. Analysis during pre-season periods assessed baseline differences between immunized and unimmunized groups. The study population included ∼140,000 seniors, of whom 50-60% were immunized annually. Adjustment for key covariates and use of propensity scores consistently increased IVE. Estimates were paradoxically higher pre-season and for all-cause mortality vs. acute respiratory hospitalization. Stratified analysis showed that those twice consecutively and currently immunized were always at significantly lower hospitalization/mortality risk with odds ratios (OR) of 0.60 [95%CI0.48-0.75] and 0.58 [0.53-0.64] pre-season and 0.77 [0.69-0.86] and 0.71 [0.66-0.77] during influenza circulation, relative to the consistently unimmunized. Conversely, those forgoing immunization when twice previously immunized were always at significantly higher hospitalization/mortality risk with OR of 1.41 [1.14-1.73] and 2.45 [2.21-2.72] pre-season and 1.21 [1.03-1.43] and 1.78 [1.61-1.96] during influenza circulation.The most pronounced IVE estimates were paradoxically observed pre-season, indicating bias tending to over-estimate vaccine protection. Change in immunization habit from that of the prior two years may be a marker for this bias in administrative data sets; however, no analytic technique explored could adjust for its influence. Improved methods to achieve valid interpretation of protection in the elderly are needed.
- Published
- 2011
- Full Text
- View/download PDF
10. Can cyclone exposure explain behavioural and demographic variation among lemur species?
- Author
-
Behie, Alison M., primary, Steffens, Travis S., additional, Yaxley, Keaghan, additional, Vincent, Alan, additional, Wright, Patricia C., additional, Johnson, Steig E., additional, and Pavelka, Mary S. M., additional
- Published
- 2024
- Full Text
- View/download PDF
11. Mercury and selenium concentrations in fishes of the Upper Colorado River Basin, southwestern United States: A retrospective assessment
- Author
-
Day, Natalie K., primary, Schmidt, Travis S., additional, Roberts, James J., additional, Osmundson, Barbara C., additional, Willacker, James J., additional, and Eagles-Smith, Collin A., additional
- Published
- 2020
- Full Text
- View/download PDF
12. Mercury and selenium concentrations in fishes of the Upper Colorado River Basin, southwestern United States: A retrospective assessment
- Author
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Barbara C. Osmundson, James J. Willacker, James J. Roberts, Natalie K. Day, Travis S. Schmidt, and Collin A. Eagles-Smith
- Subjects
River ecosystem ,010504 meteorology & atmospheric sciences ,Drainage basin ,Marine and Aquatic Sciences ,010501 environmental sciences ,Toxicology ,Pathology and Laboratory Medicine ,01 natural sciences ,Geographical locations ,Contaminants ,Medicine and Health Sciences ,Tissue Distribution ,Materials ,Mercury analysis ,Multidisciplinary ,geography.geographical_feature_category ,biology ,Fishes ,Eukaryota ,Freshwater Fish ,Chemistry ,Vertebrates ,Physical Sciences ,Freshwater fish ,Medicine ,Environmental Monitoring ,Research Article ,Chemical Elements ,Freshwater Environments ,Colorado ,Science ,Materials Science ,chemistry.chemical_element ,Selenium ,Animal science ,Rivers ,Tributary ,Southwestern United States ,Animals ,0105 earth and related environmental sciences ,Retrospective Studies ,geography ,Toxicity ,Ecology and Environmental Sciences ,Organisms ,Biology and Life Sciences ,Aquatic Environments ,Fish health ,Mercury ,Bodies of Water ,biology.organism_classification ,Molar ,United States ,Mercury (element) ,Species Interactions ,Fish ,chemistry ,North America ,Linear Models ,Earth Sciences ,Environmental science ,Metallic Mercury ,People and places - Abstract
Mercury (Hg) and selenium (Se) are contaminants of concern for fish in the Upper Colorado River Basin (UCRB). We explored Hg and Se in fish tissues (2,324 individuals) collected over 50 years (1962-2011) from the UCRB. Samples include native and non-native fish collected from lotic waterbodies spanning 7 major tributaries to the Colorado River. There was little variation of total mercury (THg) in fish assemblages basin-wide and only 13% (272/1959) of individual fish samples exceeded the fish health benchmark (0.27 μg THg/g ww). Most THg exceedances were observed in the White-Yampa tributary whereas the San Juan had the lowest mean THg concentration. Risks associated with THg are species specific with exceedances dominated by Colorado Pikeminnow (mean = 0.38 and standard error ± 0.08 μg THg/g ww) and Roundtail Chub (0.24 ± 0.06 μg THg/g ww). For Se, 48% (827/1720) of all individuals exceeded the fish health benchmark (5.1 μg Se/g dw). The Gunnison river had the most individual exceedances of the Se benchmark (74%) whereas the Dirty Devil had the fewest. We identified that species of management concern accumulate THg and Se to levels above risk thresholds and that fishes of the White-Yampa (THg) and Gunnison (Se) rivers are at the greatest risk in the UCRB.
- Published
- 2019
13. Benchmarking treewidth as a practical component of tensor network simulations
- Author
-
Blair D. Sullivan, Timothy D. Goodrich, Eugene F. Dumitrescu, Andrew L. Wright, Travis S. Humble, and Allison L. Fisher
- Subjects
Computational complexity theory ,Computer science ,Quantum simulator ,Quantum entanglement ,01 natural sciences ,010305 fluids & plasmas ,law.invention ,Network simulation ,law ,Tensor (intrinsic definition) ,Quantum ,Contraction (operator theory) ,Multidisciplinary ,Applied Mathematics ,Simulation and Modeling ,Software Engineering ,Genomics ,Benchmarking ,Physical Sciences ,Medicine ,Engineering and Technology ,Quantum Computing ,Algorithm ,Qubits ,Algorithms ,Research Article ,Optimization ,Computer and Information Sciences ,Science ,Research and Analysis Methods ,Renormalization ,Subroutines ,Factorization ,0103 physical sciences ,Line graph ,Computational Techniques ,Genetics ,Computer Graphics ,Computer Simulation ,Tensor ,010306 general physics ,Computing Systems ,Sequence Assembly Tools ,Computational Pipelines ,Biology and Life Sciences ,Computational Biology ,Graph theory ,Genome Analysis ,Tree (graph theory) ,Treewidth ,Graph Theory ,Quantum Theory ,Mathematics ,Software - Abstract
Tensor networks are powerful factorization techniques which reduce resource requirements for numerically simulating principal quantum many-body systems and algorithms. The computational complexity of a tensor network simulation depends on the tensor ranks and the order in which they are contracted. Unfortunately, computing optimal contraction sequences (orderings) in general is known to be a computationally difficult (NP-complete) task. In 2005, Markov and Shi showed that optimal contraction sequences correspond to optimal (minimum width) tree decompositions of a tensor network's line graph, relating the contraction sequence problem to a rich literature in structural graph theory. While treewidth-based methods have largely been ignored in favor of dataset-specific algorithms in the prior tensor networks literature, we demonstrate their practical relevance for problems arising from two distinct methods used in quantum simulation: multi-scale entanglement renormalization ansatz (MERA) datasets and quantum circuits generated by the quantum approximate optimization algorithm (QAOA). We exhibit multiple regimes where treewidth-based algorithms outperform domain-specific algorithms, while demonstrating that the optimal choice of algorithm has a complex dependence on the network density, expected contraction complexity, and user run time requirements. We further provide an open source software framework designed with an emphasis on accessibility and extendability, enabling replicable experimental evaluations and future exploration of competing methods by practitioners.
- Published
- 2018
14. Benchmarking treewidth as a practical component of tensor network simulations
- Author
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Dumitrescu, Eugene F., primary, Fisher, Allison L., additional, Goodrich, Timothy D., additional, Humble, Travis S., additional, Sullivan, Blair D., additional, and Wright, Andrew L., additional
- Published
- 2018
- Full Text
- View/download PDF
15. Thermal regimes of Rocky Mountain lakes warm with climate change
- Author
-
David M. Walters, Travis S. Schmidt, James J. Roberts, and Kurt D. Fausch
- Subjects
0106 biological sciences ,Atmospheric Science ,010504 meteorology & atmospheric sciences ,Trout ,lcsh:Medicine ,Marine and Aquatic Sciences ,01 natural sciences ,lcsh:Science ,Climatology ,Multidisciplinary ,biology ,Geography ,Aquatic ecosystem ,Fishes ,Temperature ,Surface Temperature ,Freshwater Fish ,Osteichthyes ,Physical Sciences ,Vertebrates ,Freshwater fish ,Seasons ,Research Article ,Freshwater Environments ,Conservation of Natural Resources ,Colorado ,Surface Properties ,Climate Change ,Summer ,Materials Science ,Material Properties ,Growing season ,Climate change ,STREAMS ,Surface Water ,Animals ,Computer Simulation ,Ecosystem ,0105 earth and related environmental sciences ,Models, Statistical ,010604 marine biology & hydrobiology ,Global warming ,lcsh:R ,Ecology and Environmental Sciences ,Lake ecosystem ,Organisms ,Aquatic Environments ,Biology and Life Sciences ,Bodies of Water ,biology.organism_classification ,Lakes ,Earth Sciences ,Environmental science ,lcsh:Q ,Physical geography ,Rocky Mountains ,Hydrology ,Surface water ,Geographic areas - Abstract
Anthropogenic climate change is causing a wide range of stresses in aquatic ecosystems, primarily through warming thermal conditions. Lakes, in response to these changes, are experiencing increases in both summer temperatures and ice-free days. We used continuous records of lake surface temperature and air temperature to create statistical models of daily mean lake surface temperature to assess thermal changes in mountain lakes. These models were combined with downscaled climate projections to predict future thermal conditions for 27 high-elevation lakes in the southern Rocky Mountains. The models predict a 0.25°C·decade-1 increase in mean annual lake surface temperature through the 2080s, which is greater than warming rates of streams in this region. Most striking is that on average, ice-free days are predicted to increase by 5.9 days ·decade-1, and summer mean lake surface temperature is predicted to increase by 0.47°C·decade-1. Both could profoundly alter the length of the growing season and potentially change the structure and function of mountain lake ecosystems. These results highlight the changes expected of mountain lakes and stress the importance of incorporating climate-related adaptive strategies in the development of resource management plans.
- Published
- 2017
16. Projected urban growth in the southeastern USA puts small streams at risk
- Author
-
Paul M. Bradley, Michael R. Meador, Sharon L. Qi, Travis S. Schmidt, Peter C. Van Metre, Michael E. Wieczorek, Ian R. Waite, Adam J. Terando, Daren M. Carlisle, Celeste A. Journey, and Barbara J. Mahler
- Subjects
010504 meteorology & atmospheric sciences ,Social Sciences ,Forests ,010501 environmental sciences ,01 natural sciences ,Agricultural land ,Water Quality ,Contaminants ,Land Use ,Materials ,Geographic Areas ,Appalachian Region ,Multidisciplinary ,Ecology ,Geography ,Fishes ,Eukaryota ,Agriculture ,Terrestrial Environments ,Freshwater Fish ,Urban ecology ,Vertebrates ,Physical Sciences ,Medicine ,Agrochemicals ,Environmental Monitoring ,Research Article ,Urban Areas ,Science ,Materials Science ,STREAMS ,Human Geography ,Ecosystems ,Ecoregion ,Rivers ,Streamflow ,Urbanization ,Animals ,Urban Ecology ,Pesticides ,0105 earth and related environmental sciences ,Conservation of Water Resources ,Land use ,Ecology and Environmental Sciences ,Organisms ,Biology and Life Sciences ,Invertebrates ,Fish ,Earth Sciences ,Environmental science ,Pest Control ,Physical geography ,Water quality - Abstract
Future land-use development has the potential to profoundly affect the health of aquatic ecosystems in the coming decades. We developed regression models predicting the loss of sensitive fish (R2 = 0.39) and macroinvertebrate (R2 = 0.64) taxa as a function of urban and agricultural land uses and applied them to projected urbanization of the rapidly urbanizing Piedmont ecoregion of the southeastern USA for 2030 and 2060. The regression models are based on a 2014 investigation of water quality and ecology of 75 wadeable streams across the region. Based on these projections, stream kilometers experiencing >50% loss of sensitive fish and invertebrate taxa will nearly quadruple to 19,500 and 38,950 km by 2060 (16 and 32% of small stream kilometers in the region), respectively. Uncertainty was assessed using the 20 and 80% probability of urbanization for the land-use projection model and using the 95% confidence intervals for the regression models. Adverse effects on stream health were linked to elevated concentrations of contaminants and nutrients, low dissolved oxygen, and streamflow alteration, all associated with urbanization. The results of this analysis provide a warning of potential risks from future urbanization and perhaps some guidance on how those risks might be mitigated.
- Published
- 2019
17. PLOS ONE
- Author
-
Eugene F. Dumitrescu, Dmitry I. Lyakh, Travis S. Humble, Alexander McCaskey, Mengsu Chen, and Physics
- Subjects
Computer and Information Sciences ,Computer science ,Vector Spaces ,Science ,Interface (computing) ,FOS: Physical sciences ,02 engineering and technology ,Quantum entanglement ,Research and Analysis Methods ,01 natural sciences ,Computer Architecture ,Computational science ,Computer Software ,Quantum circuit ,0103 physical sciences ,010306 general physics ,Wave function ,Quantum ,Quantum Mechanics ,Quantum computer ,Quantum Physics ,Multi-core processor ,Computing Systems ,Multidisciplinary ,Physics ,Simulation and Modeling ,Applied Mathematics ,Models, Theoretical ,Computer Hardware ,021001 nanoscience & nanotechnology ,Algebra ,Linear Algebra ,Qubit ,Physical Sciences ,Programming paradigm ,Medicine ,Programming Languages ,Quantum Computing ,Neural Networks, Computer ,Quantum Entanglement ,Quantum Physics (quant-ph) ,0210 nano-technology ,Qubits ,Mathematics ,Algorithms ,Research Article ,Verification and validation - Abstract
The exploration of hybrid quantum-classical algorithms and programming models on noisy near-term quantum hardware has begun. As hybrid programs scale towards classical intractability, validation and benchmarking are critical to understanding the utility of the hybrid computational model. In this paper, we demonstrate a newly developed quantum circuit simulator based on tensor network theory that enables intermediate-scale verification and validation of hybrid quantum-classical computing frameworks and programming models. We present our tensor-network quantum virtual machine (TNQVM) simulator which stores a multi-qubit wavefunction in a compressed (factorized) form as a matrix product state, thus enabling single-node simulations of larger qubit registers, as compared to brute-force state-vector simulators. Our simulator is designed to be extensible in both the tensor network form and the classical hardware used to run the simulation (multicore, GPU, distributed). The extensibility of the TNQVM simulator with respect to the simulation hardware type is achieved via a pluggable interface for different numerical backends (e.g., ITensor and Exa-TENSOR numerical libraries). We demonstrate the utility of our TNQVM quantum circuit simulator through the verification of randomized quantum circuits and the variational quantum eigensolver algorithm, both expressed within the eXtreme-scale ACCelerator (XACC) programming model. U.S. Department of Energy ASCR Quantum Algorithms Team [ERKJ332]; U.S. Department of Energy ASCR Quantum Testbed Pathfinder [ERKJ335]; Laboratory Directed Research and Development Program of Oak Ridge National Laboratory [8297]; U.S. Department of Energy Early Career Award; U.S. Department of Energy [DE-AC0500OR22725, DE-AC05-00OR22725, DE-AC05-00OR22750]; Laboratory Directed Research and Development Program of Oak Ridge National Laboratory; US Department of Energy (DOE) Office of Science Advanced Scientific Computing Research (ASCR) Early Career Research Award; DOE Office of Science ASCR quantum algorithms and testbed programs [ERKJ332, ERKJ335]; ORNL Undergraduate Research Participation Program - ORNL This work was supported by U.S. Department of Energy ASCR Quantum Algorithms Team (ERKJ332, Mr. Alexander McCaskey), U.S. Department of Energy ASCR Quantum Testbed Pathfinder (ERKJ335, Mr. Alexander McCaskey), Laboratory Directed Research and Development Program of Oak Ridge National Laboratory (ID 8297, Mr. Alexander McCaskey), and U.S. Department of Energy Early Career Award (Dr. Travis Humble). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.; This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC0500OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for the United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan. This work has been supported by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, the US Department of Energy (DOE) Office of Science Advanced Scientific Computing Research (ASCR) Early Career Research Award, and the DOE Office of Science ASCR quantum algorithms and testbed programs, under field work proposal numbers ERKJ332 and ERKJ335. This work was also supported by the ORNL Undergraduate Research Participation Program, which is sponsored by ORNL and administered jointly by ORNL and the Oak Ridge Institute for Science and Education (ORISE). ORNL is managed by UT-Battelle, LLC, for the US Department of Energy under contract no. DE-AC05-00OR22725. ORISE is managed by Oak Ridge Associated Universities for the US Department of Energy under contract no. DE-AC05-00OR22750.
- Published
- 2018
18. Lemur species-specific metapopulation responses to habitat loss and fragmentation
- Author
-
Steffens, Travis S., primary and Lehman, Shawn M., additional
- Published
- 2018
- Full Text
- View/download PDF
19. Thermal regimes of Rocky Mountain lakes warm with climate change
- Author
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Roberts, James J., primary, Fausch, Kurt D., additional, Schmidt, Travis S., additional, and Walters, David M., additional
- Published
- 2017
- Full Text
- View/download PDF
20. A syndemic approach to assess the effect of substance use and social disparities on the evolution of HIV/HCV infections in British Columbia
- Author
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James C. Johnston, Nabin Shrestha, Theodora Consolacion, David Roth, Mark Gilbert, Jason Wong, Hasina Samji, Gina Ogilvie, Mark W. Tyndall, Stanley Wong, Naveed Z. Janjua, Zahid A Butt, Amanda Yu, María Dolores Alvarez, Dionne Gesink, Robert Balshaw, Travis S. Hottes, Margot Kuo, Mel Krajden, Victoria J. Cook, Michelle Murti, and Jane A. Buxton
- Subjects
Male ,RNA viruses ,Bacterial Diseases ,Gerontology ,Human immunodeficiency virus (HIV) ,lcsh:Medicine ,HIV Infections ,Hepacivirus ,medicine.disease_cause ,Geographical locations ,0302 clinical medicine ,Syndemic ,Immunodeficiency Viruses ,Prevalence ,030212 general & internal medicine ,Young adult ,lcsh:Science ,Pathology and laboratory medicine ,Multidisciplinary ,Hepatitis C virus ,Organic Compounds ,virus diseases ,HIV diagnosis and management ,Middle Aged ,Medical microbiology ,Hepatitis C ,3. Good health ,Chemistry ,Viruses ,Physical Sciences ,Cohort ,Infectious diseases ,Female ,Pathogens ,0305 other medical science ,Research Article ,Adult ,Canada ,medicine.medical_specialty ,Tuberculosis ,Adolescent ,Substance-Related Disorders ,Viral diseases ,Microbiology ,Young Adult ,03 medical and health sciences ,Internal medicine ,Retroviruses ,medicine ,Humans ,Medicine and health sciences ,Hepatitis ,030505 public health ,British Columbia ,Biology and life sciences ,Flaviviruses ,business.industry ,Lentivirus ,Organic Chemistry ,lcsh:R ,Organisms ,Viral pathogens ,Chemical Compounds ,HIV ,Tropical Diseases ,medicine.disease ,Hepatitis viruses ,Diagnostic medicine ,digestive system diseases ,Microbial pathogens ,Socioeconomic Factors ,Co-Infections ,Alcohols ,North America ,lcsh:Q ,People and places ,Substance use ,business - Abstract
Background Co-occurrence of social conditions and infections may affect HIV/HCV disease risk and progression. We examined the changes in relationship of these social conditions and infections on HIV and hepatitis C virus (HCV) infections over time in British Columbia during 1990–2013. Methods The BC Hepatitis Testers Cohort (BC-HTC) includes ~1.5 million individuals tested for HIV or HCV, or reported as a case of HCV, HIV, HBV, or tuberculosis linked to administrative healthcare databases. We classified HCV and HIV infection status into five combinations: HIV-/HCV-, HIV+monoinfected, HIV-/HCV+seroconverters, HIV-/HCV+prevalent, and HIV+/HCV+. Results Of 1.37 million eligible individuals, 4.1% were HIV-/HCV+prevalent, 0.5% HIV+monoinfected, 0.3% HIV+/HCV+ co-infected and 0.5% HIV-/HCV+seroconverters. Overall, HIV+monoinfected individuals lived in urban areas (92%), had low injection drug use (IDU) (4%), problematic alcohol use (4%) and were materially more privileged than other groups. HIV+/HCV+ co-infected and HIV-/HCV+seroconverters were materially most deprived (37%, 32%), had higher IDU (28%, 49%), problematic alcohol use (14%, 17%) and major mental illnesses (12%, 21%). IDU, opioid substitution therapy, and material deprivation increased in HIV-/HCV+seroconverters over time. In multivariable multinomial regression models, over time, the odds of IDU declined among HIV-/HCV+prevalent and HIV+monoinfected individuals but not in HIV-/HCV+seroconverters. Declines in odds of problematic alcohol use were observed in HIV-/HCV+seroconverters and coinfected individuals over time. Conclusions These results highlight need for designing prevention, care and support services for HIV and HCV infected populations based on the evolving syndemics of infections and social conditions which vary across groups.
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- 2017
21. Cost-effectiveness of internet-based HIV screening among gay, bisexual and other men who have sex with men (GBMSM) in Metro Vancouver, Canada.
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Jose A De Anda, Michael A Irvine, Wei Zhang, Travis Salway, Devon Haag, and Mark Gilbert
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Medicine ,Science - Abstract
BackgroundGetCheckedOnline is an internet-based screening service aiming to increase HIV testing among gay, bisexual and other men who have sex with men (GBMSM). We assessed the cost-effectiveness of GetCheckedOnline in its first implementation phase at different uptake scenarios compared to clinic-based screening services alone in Metro Vancouver, Canada.MethodsFrom a healthcare payer's perspective, our cost-utility analysis used an established dynamic GBMSM HIV compartmental model estimating the probability of acquiring HIV, progressing through diagnosis, disease stages and treatment over a 30-year time horizon. The base case scenario assumed 4.7% uptake of GetCheckedOnline in 2016 (remainder using clinic-based services), with 74% of high-risk and 44% of low-risk infrequent testers becoming regular testers in five years. Scenario analyses tested increased GetCheckedOnline uptake to 10% and 15%.ResultsThe cost per test for GetCheckedOnline was $29.40 compared to clinic-based services $56.92. Compared with clinic-based screening services, the projected increase in testing frequency with 4.7% uptake of GetCheckedOnline increased the costs by $329,600 (95% Credible Interval: -$498,200, $571,000) and gained 4.53 (95%CrI: 0, 9.20) quality-adjusted life years (QALYs) in a 30-year time horizon. The probability of GetCheckedOnline being cost-effective was 34% at the threshold of $50,000 per QALY, and increased to 73% at the threshold of $100,000 per QALY. The results were consistent in the other uptake scenarios. The probability of GetCheckedOnline being cost-effective became 80% at the threshold of $50,000 per QALY if assuming 5-year time horizon.ConclusionsGetCheckedOnline is almost half the cost of clinic-based services on a per-test basis. However, increased access to testing should be balanced with risk profiles of patients to ensure the implementation can be a cost-effective strategy for increasing HIV screening among GBMSM in Metro Vancouver. Additional analyses are needed to understand the impact of internet-based screening including screening for other STIs and in other populations.
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- 2023
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22. A systematic review of the prevalence of lifetime experience with 'conversion' practices among sexual and gender minority populations.
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Travis Salway, David J Kinitz, Hannah Kia, Florence Ashley, Dean Giustini, Amrit Tiwana, Reilla Archibald, Amirali Mallakzadeh, Elisabeth Dromer, Olivier Ferlatte, Trevor Goodyear, and Alex Abramovich
- Subjects
Medicine ,Science - Abstract
RationaleConversion practices (CPs) refer to organized attempts to deter people from adopting or expressing non-heterosexual identities or gender identities that differ from their gender/sex assigned at birth. Numerous jurisdictions have contemplated or enacted legislative CP bans in recent years. Syntheses of CP prevalence are needed to inform further public health policy and action.ObjectivesTo conduct a systematic review describing CP prevalence estimates internationally and exploring heterogeneity across country and socially relevant subgroups.MethodsWe performed literature searches in eight databases (Medline, Embase, PsycInfo, Social Work Abstracts, CINAHL, Web of Science, LGBTQ+ Source, and Proquest Dissertations) and included studies from all jurisdictions, globally, conducted after 2000 with a sampling frame of sexual and gender minority (SGM) people, as well as studies of practitioners seeing SGM patients. We used the Hoy et al. risk of bias tool for prevalence studies and summarized distribution of estimates using median and range.ResultsWe identified fourteen articles that reported prevalence estimates among SGM populations, and two articles that reported prevalence estimates from studies of mental health practitioners. Prevalence estimates among SGM samples ranged 2%-34% (median: 8.5). Prevalence estimates were greater in studies conducted in the US (median: 13%), compared to Canada (median: 7%), and greater among transgender (median: 12%), compared to cisgender (median: 4%) subsamples. Prevalence estimates were greatest among people assigned male at birth, whether transgender (median: 10%) or cisgender (median: 8%), as compared to people assigned female at birth (medians: 5% among transgender participants, 3% among cisgender participants). Further differences were observed by race (medians: 8% among Indigenous and other racial minorities, 5% among white groups) but not by sexual orientation.ConclusionsCPs remain prevalent, despite denouncements from professional bodies. Social inequities in CP prevalence signal the need for targeted efforts to protect transgender, Indigenous and racial minority, and assigned-male-at-birth subgroups.
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- 2023
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23. Cemented vs Uncemented hemiarthroplasties for femoral neck fractures: An overlapping systematic review and evidence appraisal.
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Arjun K Reddy, Jared T Scott, Grayson R Norris, Chip Moore, Jake X Checketts, Griffin K Hughes, Travis Small, Mark M Calder, and Brent L Norris
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Medicine ,Science - Abstract
BackgroundThe purpose of our study is to assess the methodology of overlapping systematic reviews related to cemented vs uncemented hip hemiarthroplasties for the treatment of femoral neck fractures to find the study with the best evidence. Also, we assess the gaps in methodology and information to help with direction of future studies.MethodsA systematic search was conducted in September 2022 using Pubmed, Embase, and Cochrane Library. Clinical outcome data and characteristics of each study were extracted to see which treatment had better favorability. The outcomes and characteristics extracted from each study includes, first author, search date, publication journal and date, number of studies included, databases, level of evidence, software used, subgroup analyses that were conducted, and heterogeneity with the use of I2 statistics Methodological quality information was extracted from each study using four different methodologic scores (Oxford Levels of Evidence; Assessment of Multiple Systematic Reviews (AMSTAR); Quality of reporting of meta-analyses (QUROM); Oxman and Guyatt. After that, the Jadad decision algorithm was used to identify which studies in our sample contained the best available evidence. Finally, overlap of each systematic review was assessed using Corrected Covered Area (CCA) to look at redundancy and research waste among the systematic reviews published on the topic.ResultsAfter screening, 12 studies were included in our sample. For the Oxford Levels of Evidence, we found that all the studies were Level I evidence. For the QUORUM assessment, we had 1 study with the highest score of 18. Additionally, we did the Oxman and Guyatt assessment, where we found 4 studies with a maximum score of 6. Finally, we did an AMSTAR assessment and found 2 studies with a score of 9. After conducting the methodological scores; the authors determined that Li. L et al 2021 had the highest quality. In addition, it was found that the CCA found among the primary studies in each systematic review calculated to .22. Any CCA above .15 is considered "very high overlap".ConclusionsThe best available evidence suggests that Cemented HAs are better at preventing Prosthesis-related complications. Conversely, the best evidence also suggests that Cemented HA also results in longer operative time and increased intraoperative blood loss. When conducting future systematic reviews related to the topic, we ask that authors restrict conducting another systematic review until new evidence emerges so as not to confuse the clinical decision-making of physicians.
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- 2023
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24. Midkine-a protein localization in the developing and adult retina of the zebrafish and its function during photoreceptor regeneration
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Scott M Taylor, Ryan Thummel, Travis S D'Cruz, Esther Gramage, and Peter F. Hitchcock
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Morpholino ,genetic structures ,Science ,Biology ,03 medical and health sciences ,0302 clinical medicine ,Retinal Rod Photoreceptor Cells ,medicine ,Animals ,Regeneration ,Outer nuclear layer ,Zebrafish ,030304 developmental biology ,Cell Proliferation ,0303 health sciences ,Retina ,Multidisciplinary ,Midkine ,Zebrafish Proteins ,Inner plexiform layer ,biology.organism_classification ,Embryonic stem cell ,Cell biology ,Circadian Rhythm ,Protein Transport ,medicine.anatomical_structure ,Medicine ,Cytokines ,sense organs ,Muller glia ,030217 neurology & neurosurgery ,Research Article - Abstract
Midkine is a heparin binding growth factor with important functions in neuronal development and survival, but little is known about its function in the retina. Previous studies show that in the developing zebrafish, Midkine-a (Mdka) regulates cell cycle kinetics in retinal progenitors, and following injury to the adult zebrafish retina, mdka is strongly upregulated in Müller glia and the injury-induced photoreceptor progenitors. Here we provide the first data describing Mdka protein localization during different stages of retinal development and during the regeneration of photoreceptors in adults. We also experimentally test the role of Mdka during photoreceptor regeneration. The immuno-localization of Mdka reflects the complex spatiotemporal pattern of gene expression and also reveals the apparent secretion and extracellular trafficking of this protein. During embryonic retinal development the Mdka antibodies label all mitotically active cells, but at the onset of neuronal differentiation, immunostaining is also localized to the nascent inner plexiform layer. Starting at five days post fertilization through the juvenile stage, Mdka immunostaining labels the cytoplasm of horizontal cells and the overlying somata of rod photoreceptors. Double immunolabeling shows that in adult horizontal cells, Mdka co-localizes with markers of the Golgi complex. Together, these data are interpreted to show that Mdka is synthesized in horizontal cells and secreted into the outer nuclear layer. In adults, Mdka is also present in the end feet of Müller glia. Similar to mdka gene expression, Mdka in horizontal cells is regulated by circadian rhythms. After the light-induced death of photoreceptors, Mdka immuonolabeling is localized to Müller glia, the intrinsic stem cells of the zebrafish retina, and proliferating photoreceptor progenitors. Knockdown of Mdka during photoreceptor regeneration results in less proliferation and diminished regeneration of rod photoreceptors. These data suggest that during photoreceptor regeneration Mdka regulates aspects of injury-induced cell proliferation.
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- 2014
25. Influenza vaccine effectiveness in the elderly based on administrative databases: change in immunization habit as a marker for bias
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Leslie L. Roos, Travis S. Hottes, Gaston De Serres, Barbara J. Law, Paul Van Caeseele, Danuta M. Skowronski, Naveed Z. Janjua, and Brett Hiebert
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Male ,Viral Diseases ,Time Factors ,Epidemiology ,lcsh:Medicine ,computer.software_genre ,0302 clinical medicine ,Odds Ratio ,030212 general & internal medicine ,lcsh:Science ,media_common ,Geriatrics ,Aged, 80 and over ,0303 health sciences ,education.field_of_study ,Vaccines ,Multidisciplinary ,Database ,Mortality rate ,Vaccination ,Aging and Immunity ,Immunizations ,3. Good health ,Hospitalization ,Treatment Outcome ,Infectious Diseases ,Databases as Topic ,Influenza Vaccines ,Medicine ,Female ,Seasons ,Public Health ,Research Article ,medicine.medical_specialty ,Canada ,Influenza vaccine ,media_common.quotation_subject ,Population ,Immunology ,MEDLINE ,Microbiology ,Infectious Disease Epidemiology ,03 medical and health sciences ,Bias ,Virology ,Influenza, Human ,medicine ,Humans ,education ,Biology ,030304 developmental biology ,Aged ,business.industry ,lcsh:R ,Immunity ,Viral Vaccines ,Odds ratio ,Influenza ,Immunization ,lcsh:Q ,Clinical Immunology ,Habit ,business ,computer - Abstract
Background Administrative databases provide efficient methods to estimate influenza vaccine effectiveness (IVE) against severe outcomes in the elderly but are prone to intractable bias. This study returns to one of the linked population databases by which IVE against hospitalization and death in the elderly was first assessed. We explore IVE across six more recent influenza seasons, including periods before, during, and after peak activity to identify potential markers for bias. Methods and Findings Acute respiratory hospitalization and all-cause mortality were compared between immunized/non-immunized community-dwelling seniors ≥65years through administrative databases in Manitoba, Canada between 2000-01 and 2005-06. IVE was compared during pre-season/influenza/post-season periods through logistic regression with multivariable adjustment (age/sex/income/residence/prior influenza or pneumococcal immunization/medical visits/comorbidity), stratification based on prior influenza immunization history, and propensity scores. Analysis during pre-season periods assessed baseline differences between immunized and unimmunized groups. The study population included ∼140,000 seniors, of whom 50–60% were immunized annually. Adjustment for key covariates and use of propensity scores consistently increased IVE. Estimates were paradoxically higher pre-season and for all-cause mortality vs. acute respiratory hospitalization. Stratified analysis showed that those twice consecutively and currently immunized were always at significantly lower hospitalization/mortality risk with odds ratios (OR) of 0.60 [95%CI0.48–0.75] and 0.58 [0.53–0.64] pre-season and 0.77 [0.69–0.86] and 0.71 [0.66–0.77] during influenza circulation, relative to the consistently unimmunized. Conversely, those forgoing immunization when twice previously immunized were always at significantly higher hospitalization/mortality risk with OR of 1.41 [1.14–1.73] and 2.45 [2.21–2.72] pre-season and 1.21 [1.03–1.43] and 1.78 [1.61–1.96] during influenza circulation. Conclusions The most pronounced IVE estimates were paradoxically observed pre-season, indicating bias tending to over-estimate vaccine protection. Change in immunization habit from that of the prior two years may be a marker for this bias in administrative data sets; however, no analytic technique explored could adjust for its influence. Improved methods to achieve valid interpretation of protection in the elderly are needed.
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- 2011
26. Deconvolution of Complex 1D NMR Spectra Using Objective Model Selection
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Hughes, Travis S., primary, Wilson, Henry D., additional, de Vera, Ian Mitchelle S., additional, and Kojetin, Douglas J., additional
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- 2015
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27. A syndemic approach to assess the effect of substance use and social disparities on the evolution of HIV/HCV infections in British Columbia.
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Butt, Zahid Ahmad, Shrestha, Nabin, Wong, Stanley, Kuo, Margot, Gesink, Dionne, Gilbert, Mark, Wong, Jason, Yu, Amanda, Alvarez, Maria, Samji, Hasina, Buxton, Jane A., Johnston, James C., Cook, Victoria J., Roth, David, Consolacion, Theodora, Murti, Michelle, Hottes, Travis S., Ogilvie, Gina, Balshaw, Robert, and Tyndall, Mark W.
- Subjects
HIV ,HEPATITIS C virus ,HEALTH equity ,SUBSTANCE-induced disorders ,CHRONIC kidney failure - Abstract
Background: Co-occurrence of social conditions and infections may affect HIV/HCV disease risk and progression. We examined the changes in relationship of these social conditions and infections on HIV and hepatitis C virus (HCV) infections over time in British Columbia during 1990–2013. Methods: The BC Hepatitis Testers Cohort (BC-HTC) includes ~1.5 million individuals tested for HIV or HCV, or reported as a case of HCV, HIV, HBV, or tuberculosis linked to administrative healthcare databases. We classified HCV and HIV infection status into five combinations: HIV-/HCV-, HIV+monoinfected, HIV-/HCV+seroconverters, HIV-/HCV+prevalent, and HIV+/HCV+. Results: Of 1.37 million eligible individuals, 4.1% were HIV-/HCV+prevalent, 0.5% HIV+monoinfected, 0.3% HIV+/HCV+ co-infected and 0.5% HIV-/HCV+seroconverters. Overall, HIV+monoinfected individuals lived in urban areas (92%), had low injection drug use (IDU) (4%), problematic alcohol use (4%) and were materially more privileged than other groups. HIV+/HCV+ co-infected and HIV-/HCV+seroconverters were materially most deprived (37%, 32%), had higher IDU (28%, 49%), problematic alcohol use (14%, 17%) and major mental illnesses (12%, 21%). IDU, opioid substitution therapy, and material deprivation increased in HIV-/HCV+seroconverters over time. In multivariable multinomial regression models, over time, the odds of IDU declined among HIV-/HCV+prevalent and HIV+monoinfected individuals but not in HIV-/HCV+seroconverters. Declines in odds of problematic alcohol use were observed in HIV-/HCV+seroconverters and coinfected individuals over time. Conclusions: These results highlight need for designing prevention, care and support services for HIV and HCV infected populations based on the evolving syndemics of infections and social conditions which vary across groups. [ABSTRACT FROM AUTHOR]
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- 2017
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28. Thermal regimes of Rocky Mountain lakes warm with climate change.
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Schmidt, Travis S., Roberts, James J., Walters, David M., and Fausch, Kurt D.
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GEOTHERMAL ecology , *CLIMATE change , *GLOBAL warming , *SURFACE temperature - Abstract
Anthropogenic climate change is causing a wide range of stresses in aquatic ecosystems, primarily through warming thermal conditions. Lakes, in response to these changes, are experiencing increases in both summer temperatures and ice-free days. We used continuous records of lake surface temperature and air temperature to create statistical models of daily mean lake surface temperature to assess thermal changes in mountain lakes. These models were combined with downscaled climate projections to predict future thermal conditions for 27 high-elevation lakes in the southern Rocky Mountains. The models predict a 0.25°C·decade-1 increase in mean annual lake surface temperature through the 2080s, which is greater than warming rates of streams in this region. Most striking is that on average, ice-free days are predicted to increase by 5.9 days ·decade-1, and summer mean lake surface temperature is predicted to increase by 0.47°C·decade-1. Both could profoundly alter the length of the growing season and potentially change the structure and function of mountain lake ecosystems. These results highlight the changes expected of mountain lakes and stress the importance of incorporating climate-related adaptive strategies in the development of resource management plans. [ABSTRACT FROM AUTHOR]
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- 2017
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29. Post-Translational Processing of Synaptophysin in the Rat Retina Is Disrupted by Diabetes
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D’Cruz, Travis S., primary, Weibley, Brittany N., additional, Kimball, Scot R., additional, and Barber, Alistair J., additional
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- 2012
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30. Influenza Vaccine Effectiveness in the Elderly Based on Administrative Databases: Change in Immunization Habit as a Marker for Bias
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Hottes, Travis S., primary, Skowronski, Danuta M., additional, Hiebert, Brett, additional, Janjua, Naveed Z., additional, Roos, Leslie L., additional, Van Caeseele, Paul, additional, Law, Barbara J., additional, and De Serres, Gaston, additional
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- 2011
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31. A prospective study of the adaptive changes in the gut microbiome during standard-of-care chemoradiotherapy for gynecologic cancers.
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Molly B El Alam, Travis T Sims, Ramez Kouzy, Greyson W G Biegert, Joseph A B I Jaoude, Tatiana V Karpinets, Kyoko Yoshida-Court, Xiaogang Wu, Andrea Y Delgado-Medrano, Melissa P Mezzari, Nadim J Ajami, Travis Solley, Mustapha Ahmed-Kaddar, Lilie L Lin, Lois Ramondetta, Amir Jazaeri, Anuja Jhingran, Patricia J Eifel, Kathleen M Schmeler, Jennifer Wargo, Ann H Klopp, and Lauren E Colbert
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Medicine ,Science - Abstract
BackgroundA diverse and abundant gut microbiome can improve cancer patients' treatment response; however, the effect of pelvic chemoradiotherapy (CRT) on gut diversity and composition is unclear. The purpose of this prospective study was to identify changes in the diversity and composition of the gut microbiome during and after pelvic CRT.Materials and methodsRectal swabs from 58 women with cervical, vaginal, or vulvar cancer from two institutions were prospectively analyzed before CRT (baseline), during CRT (weeks 1, 3, and 5), and at first follow-up (week 12) using 16Sv4 rRNA gene sequencing of the V4 hypervariable region of the bacterial 16S rRNA marker gene. 42 of these patients received antibiotics during the study period. Observed operational taxonomic units (OTUs; representative of richness) and Shannon, Simpson, Inverse Simpson, and Fisher diversity indices were used to characterize alpha (within-sample) diversity. Changes over time were assessed using a paired t-test, repeated measures ANOVA, and linear mixed modeling. Compositional changes in specific bacteria over time were evaluated using linear discriminant analysis effect size.ResultsGut microbiome richness and diversity levels continually decreased throughout CRT (mean Shannon diversity index, 2.52 vs. 2.91; all P ConclusionAfter CRT, the diversity of the gut microbiomes in this population tended to return to baseline levels by the 12 week follow-up period, but structure and composition remained significantly altered. These changes should be considered when designing studies to analyze the gut microbiome in patients who receive pelvic CRT for gynecologic cancers.
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- 2021
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32. Experiences with sexual orientation and gender identity conversion therapy practices among sexual minority men in Canada, 2019-2020.
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Travis Salway, Stephen Juwono, Ben Klassen, Olivier Ferlatte, Aidan Ablona, Harlan Pruden, Jeffrey Morgan, Michael Kwag, Kiffer Card, Rod Knight, and Nathan J Lachowsky
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Medicine ,Science - Abstract
Background"Conversion therapy" practices (CTP) are organized and sustained efforts to avoid the adoption of non-heterosexual sexual orientations and/or of gender identities not assigned at birth. Few data are available to inform the contemporary prevalence of CTP. The aim of this study is to quantify the prevalence of CTP among Canadian sexual and gender minority men, including details regarding the setting, age of initiation, and duration of CTP exposure.MethodsSexual and gender minority men, including transmen and non-binary individuals, aged ≥ 15, living in Canada were recruited via social media and networking applications and websites, November 2019-February 2020. Participants provided demographic data and detailed information about their experiences with CTP.Results21% of respondents (N = 9,214) indicated that they or any person with authority (e.g., parent, caregiver) ever tried to change their sexual orientation or gender identity, and 10% had experienced CTP. CTP experience was highest among non-binary (20%) and transgender respondents (19%), those aged 15-19 years (13%), immigrants (15%), and racial/ethnic minorities (11-22%, with variability by identity). Among the n = 910 participants who experienced CTP, most experienced CTP in religious/faith-based settings (67%) or licensed healthcare provider offices (20%). 72% of those who experienced CTP first attended before the age of 20 years, 24% attended for one year or longer, and 31% attended more than five sessions.InterpretationCTP remains prevalent in Canada and is most prevalent among younger cohorts, transgender people, immigrants, and racial/ethnic minorities. Legislation, policy, and education are needed that target both religious and healthcare settings.
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- 2021
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33. At-home self-collection of saliva, oropharyngeal swabs and dried blood spots for SARS-CoV-2 diagnosis and serology: Post-collection acceptability of specimen collection process and patient confidence in specimens.
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Mariah Valentine-Graves, Eric Hall, Jodie Lynn Guest, Elizabeth Adam, Rachel Valencia, Kaitlin Shinn, Isabel Hardee, Travis Sanchez, Aaron J Siegler, and Patrick Sean Sullivan
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Medicine ,Science - Abstract
BackgroundOptions to increase the ease of testing for SARS-CoV-2 infection and immune response are needed. Self-collection of diagnostic specimens at home offers an avenue to allow people to test for SARS-CoV-2 infection or immune response without traveling to a clinic or laboratory. Before this study, survey respondents indicated willingness to self-collect specimens for COVID-related tests, but hypothetical willingness can differ from post-collection acceptability after participants collect specimens.Methods153 US adults were enrolled in a study of the willingness and feasibility of patients to self-collect three diagnostic specimens (saliva, oropharyngeal swab (OPS) and dried blood spot (DBS) card) while observed by a clinician through a telehealth session. After the specimens were collected, 148 participants participated in a survey about the acceptability of the collection, packing and shipping process, and their confidence in the samples collected for COVID-related laboratory testing.ResultsA large majority of participants (>84%) reported that collecting, packing and shipping of saliva, OPS, and DBS specimens were acceptable. Nearly nine in 10 (87%) reported being confident or very confident that the specimens they collected were sufficient for laboratory analysis.There were no differences in acceptability for any specimen type, packing and shipping, or confidence in samples, by gender, age, race/ethnicity, or educational level.ConclusionsSelf-collection of specimens for SARS-CoV-2 testing, and preparing and shipping specimens for analysis, were acceptable in a diverse group of US adults. Further refinement of materials and instructions to support self-collection of saliva, OPS and DBS specimens for COVID-related testing is needed.
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- 2020
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34. Unmasking individual differences in adult reading procedures by disrupting holistic orthographic perception.
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Elizabeth A Hirshorn, Travis Simcox, Corrine Durisko, Charles A Perfetti, and Julie A Fiez
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Medicine ,Science - Abstract
Word identification is undeniably important for skilled reading and ultimately reading comprehension. Interestingly, both lexical and sublexical procedures can support word identification. Recent cross-linguistic comparisons have demonstrated that there are biases in orthographic coding (e.g., holistic vs. analytic) linked with differences in writing systems, such that holistic orthographic coding is correlated with lexical-level reading procedures and vice versa. The current study uses a measure of holistic visual processing used in the face processing literature, orientation sensitivity, to test individual differences in word identification within a native English population. Results revealed that greater orientation sensitivity (i.e., greater holistic processing) was associated with a reading profile that relies less on sublexical phonological measures and more on lexical-level characteristics within the skilled English readers. Parallels to Chinese procedures of reading and a proposed alternative route to skilled reading are discussed.
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- 2020
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35. Post-Translational Processing of Synaptophysin in the Rat Retina Is Disrupted by Diabetes.
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D'Cruz, Travis S., Weibley, Brittany N., Kimball, Scot R., Barber, Alistair J., and Linden, Rafael
- Subjects
- *
SYNAPTOPHYSIN , *RETINA , *DIABETES , *POST-translational modification , *GENETIC translation , *GENETIC code - Abstract
Synaptophysin, is an abundant presynaptic protein involved in synaptic vesicle recycling and neurotransmitter release. Previous work shows that its content is significantly reduced in the rat retina by streptozotocin (STZ)-diabetes. This study tested the hypothesis that STZ-diabetes alters synaptophysin protein turnover and glycosylation in the rat retina. Whole explant retinas from male Sprague-Dawley rats were used in this study. Rats were made diabetic by a single intraperitoneal STZ injection (65 mg/kg body weight in 10 mM sodium citrate, pH 4.5). mRNA translation was measured using a 35Smethionine labeling assay followed by synaptophysin immunoprecipitation and autoradiography. A pulse-chase study was used to determine the depletion of newly synthesized synaptophysin. Depletion of total synaptophysin was determined after treatment with cycloheximide. Mannose rich N-glycosylated synaptophysin was detected by treating retinal lysates with endoglycosidase H followed by immunoblot analysis. Synaptophysin mRNA translation was significantly increased after 1 month (p<0.001) and 2 months (p<0.05) of STZ-diabetes, compared to age-matched controls. Newly synthesized synaptophysin degradation was significantly accelerated in the retina after 1 and 2 months of diabetes compared to controls (p<0.05). Mannose rich glycosylated synaptophysin was significantly increased after 1 month of STZ-diabetes compared to controls (p<0.05).These data suggest that diabetes increases mRNA translation of synaptophysin in the retina, resulting in an accumulation of mannose rich glycosylated synaptophysin, a transient post-translational state of the protein. This diabetes-induced irregularity in post-translational processing could explain the accelerated degradation of retinal synaptophysin in diabetes. [ABSTRACT FROM AUTHOR]
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- 2012
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36. Projected urban growth in the southeastern USA puts small streams at risk.
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Peter C Van Metre, Ian R Waite, Sharon Qi, Barbara Mahler, Adam Terando, Michael Wieczorek, Michael Meador, Paul Bradley, Celeste Journey, Travis Schmidt, and Daren Carlisle
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Medicine ,Science - Abstract
Future land-use development has the potential to profoundly affect the health of aquatic ecosystems in the coming decades. We developed regression models predicting the loss of sensitive fish (R2 = 0.39) and macroinvertebrate (R2 = 0.64) taxa as a function of urban and agricultural land uses and applied them to projected urbanization of the rapidly urbanizing Piedmont ecoregion of the southeastern USA for 2030 and 2060. The regression models are based on a 2014 investigation of water quality and ecology of 75 wadeable streams across the region. Based on these projections, stream kilometers experiencing >50% loss of sensitive fish and invertebrate taxa will nearly quadruple to 19,500 and 38,950 km by 2060 (16 and 32% of small stream kilometers in the region), respectively. Uncertainty was assessed using the 20 and 80% probability of urbanization for the land-use projection model and using the 95% confidence intervals for the regression models. Adverse effects on stream health were linked to elevated concentrations of contaminants and nutrients, low dissolved oxygen, and streamflow alteration, all associated with urbanization. The results of this analysis provide a warning of potential risks from future urbanization and perhaps some guidance on how those risks might be mitigated.
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- 2019
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37. Measuring population transmission risk for HIV: an alternative metric of exposure risk in men who have sex with men (MSM) in the US.
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Colleen F Kelley, Eli S Rosenberg, Brandon M O'Hara, Paula M Frew, Travis Sanchez, John L Peterson, Carlos Del Rio, and Patrick S Sullivan
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Medicine ,Science - Abstract
BackgroundVarious metrics for HIV burden and treatment success [e.g. HIV prevalence, community viral load (CVL), population viral load (PVL), percent of HIV-positive persons with undetectable viral load] have important public health limitations for understanding disparities.Methods and findingsUsing data from an ongoing HIV incidence cohort of black and white men who have sex with men (MSM), we propose a new metric to measure the prevalence of those at risk of transmitting HIV and illustrate its value. MSM with plasma VL>400 copies/mL were defined as having 'transmission risk'. We calculated HIV prevalence, CVL, PVL, percent of HIV-positive with undetectable viral loads, and prevalence of plasma VL>400 copies/ml (%VL400) for black and white MSM. We used Monte Carlo simulation incorporating data on sexual mixing by race to estimate exposure of black and white HIV-negative MSM to a partner with transmission risk via unprotected anal intercourse (UAI). Of 709 MSM recruited, 42% (168/399) black and 14% (44/310) white MSM tested HIV-positive (pDiscussionDespite similarities in other metrics, black MSM in our cohort are three times as likely as white MSM to have HIV transmission risk. With comparable risk behaviors, HIV-negative black MSM have a substantially higher likelihood of encountering a UAI partner at risk of transmitting HIV. Our results support increasing HIV testing, linkage to care, and antiretroviral treatment of HIV-positive MSM to reduce prevalence of those with transmission risk, particularly for black MSM.
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- 2012
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38. Active site mutations change the cleavage specificity of neprilysin.
- Author
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Travis Sexton, Lisa J Hitchcook, David W Rodgers, Luke H Bradley, and Louis B Hersh
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Medicine ,Science - Abstract
Neprilysin (NEP), a member of the M13 subgroup of the zinc-dependent endopeptidase family is a membrane bound peptidase capable of cleaving a variety of physiological peptides. We have generated a series of neprilysin variants containing mutations at either one of two active site residues, Phe(563) and Ser(546). Among the mutants studied in detail we observed changes in their activity towards leucine(5)-enkephalin, insulin B chain, and amyloid β(1-40). For example, NEP(F563I) displayed an increase in preference towards cleaving leucine(5)-enkephalin relative to insulin B chain, while mutant NEP(S546E) was less discriminating than neprilysin. Mutants NEP(F563L) and NEP(S546E) exhibit different cleavage site preferences than neprilysin with insulin B chain and amyloid ß(1-40) as substrates. These data indicate that it is possible to alter the cleavage site specificity of neprilysin opening the way for the development of substrate specific or substrate exclusive forms of the enzyme with enhanced therapeutic potential.
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- 2012
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39. Development and evaluation of a genome-wide 6K SNP array for diploid sweet cherry and tetraploid sour cherry.
- Author
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Cameron Peace, Nahla Bassil, Dorrie Main, Stephen Ficklin, Umesh R Rosyara, Travis Stegmeir, Audrey Sebolt, Barbara Gilmore, Cindy Lawley, Todd C Mockler, Douglas W Bryant, Larry Wilhelm, and Amy Iezzoni
- Subjects
Medicine ,Science - Abstract
High-throughput genome scans are important tools for genetic studies and breeding applications. Here, a 6K SNP array for use with the Illumina Infinium® system was developed for diploid sweet cherry (Prunus avium) and allotetraploid sour cherry (P. cerasus). This effort was led by RosBREED, a community initiative to enable marker-assisted breeding for rosaceous crops. Next-generation sequencing in diverse breeding germplasm provided 25 billion basepairs (Gb) of cherry DNA sequence from which were identified genome-wide SNPs for sweet cherry and for the two sour cherry subgenomes derived from sweet cherry (avium subgenome) and P. fruticosa (fruticosa subgenome). Anchoring to the peach genome sequence, recently released by the International Peach Genome Initiative, predicted relative physical locations of the 1.9 million putative SNPs detected, preliminarily filtered to 368,943 SNPs. Further filtering was guided by results of a 144-SNP subset examined with the Illumina GoldenGate® assay on 160 accessions. A 6K Infinium® II array was designed with SNPs evenly spaced genetically across the sweet and sour cherry genomes. SNPs were developed for each sour cherry subgenome by using minor allele frequency in the sour cherry detection panel to enrich for subgenome-specific SNPs followed by targeting to either subgenome according to alleles observed in sweet cherry. The array was evaluated using panels of sweet (n = 269) and sour (n = 330) cherry breeding germplasm. Approximately one third of array SNPs were informative for each crop. A total of 1825 polymorphic SNPs were verified in sweet cherry, 13% of these originally developed for sour cherry. Allele dosage was resolved for 2058 polymorphic SNPs in sour cherry, one third of these being originally developed for sweet cherry. This publicly available genomics resource represents a significant advance in cherry genome-scanning capability that will accelerate marker-locus-trait association discovery, genome structure investigation, and genetic diversity assessment in this diploid-tetraploid crop group.
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- 2012
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40. A new threat to honey bees, the parasitic phorid fly Apocephalus borealis.
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Andrew Core, Charles Runckel, Jonathan Ivers, Christopher Quock, Travis Siapno, Seraphina Denault, Brian Brown, Joseph Derisi, Christopher D Smith, and John Hafernik
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Medicine ,Science - Abstract
Honey bee colonies are subject to numerous pathogens and parasites. Interaction among multiple pathogens and parasites is the proposed cause for Colony Collapse Disorder (CCD), a syndrome characterized by worker bees abandoning their hive. Here we provide the first documentation that the phorid fly Apocephalus borealis, previously known to parasitize bumble bees, also infects and eventually kills honey bees and may pose an emerging threat to North American apiculture. Parasitized honey bees show hive abandonment behavior, leaving their hives at night and dying shortly thereafter. On average, seven days later up to 13 phorid larvae emerge from each dead bee and pupate away from the bee. Using DNA barcoding, we confirmed that phorids that emerged from honey bees and bumble bees were the same species. Microarray analyses of honey bees from infected hives revealed that these bees are often infected with deformed wing virus and Nosema ceranae. Larvae and adult phorids also tested positive for these pathogens, implicating the fly as a potential vector or reservoir of these honey bee pathogens. Phorid parasitism may affect hive viability since 77% of sites sampled in the San Francisco Bay Area were infected by the fly and microarray analyses detected phorids in commercial hives in South Dakota and California's Central Valley. Understanding details of phorid infection may shed light on similar hive abandonment behaviors seen in CCD.
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- 2012
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41. Mesenchymal stem cells promote mammosphere formation and decrease E-cadherin in normal and malignant breast cells.
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Ann H Klopp, Lara Lacerda, Anshul Gupta, Bisrat G Debeb, Travis Solley, Li Li, Erika Spaeth, Wei Xu, Xiaomei Zhang, Michael T Lewis, James M Reuben, Savitri Krishnamurthy, Mauro Ferrari, Rogério Gaspar, Thomas A Buchholz, Massimo Cristofanilli, Frank Marini, Michael Andreeff, and Wendy A Woodward
- Subjects
Medicine ,Science - Abstract
Normal and malignant breast tissue contains a rare population of multi-potent cells with the capacity to self-renew, referred to as stem cells, or tumor initiating cells (TIC). These cells can be enriched by growth as "mammospheres" in three-dimensional cultures.We tested the hypothesis that human bone-marrow derived mesenchymal stem cells (MSC), which are known to support tumor growth and metastasis, increase mammosphere formation.We found that MSC increased human mammary epithelial cell (HMEC) mammosphere formation in a dose-dependent manner. A similar increase in sphere formation was seen in human inflammatory (SUM149) and non-inflammatory breast cancer cell lines (MCF-7) but not in primary inflammatory breast cancer cells (MDA-IBC-3). We determined that increased mammosphere formation can be mediated by secreted factors as MSC conditioned media from MSC spheroids significantly increased HMEC, MCF-7 and SUM149 mammosphere formation by 6.4 to 21-fold. Mammospheres grown in MSC conditioned media had lower levels of the cell adhesion protein, E-cadherin, and increased expression of N-cadherin in SUM149 and HMEC cells, characteristic of a pro-invasive mesenchymal phenotype. Co-injection with MSC in vivo resulted in a reduced latency time to develop detectable MCF-7 and MDA-IBC-3 tumors and increased the growth of MDA-IBC-3 tumors. Furthermore, E-cadherin expression was decreased in MDA-IBC-3 xenografts with co-injection of MSC.MSC increase the efficiency of primary mammosphere formation in normal and malignant breast cells and decrease E-cadherin expression, a biologic event associated with breast cancer progression and resistance to therapy.
- Published
- 2010
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