392 research outputs found
Elucidating the Factors that Modulate the Distribution of Avian Haemosporida Parasites across a Community of Hosts
Parasites are heterogeneously distributed across host species, host populations, and host individuals within populations. A primary aim of infectious disease ecology seeks to uncover the factors that drive this heterogeneity. At a fundamental level, host infection is determined by exposure and susceptibility to a pathogen. My dissertation explores how evolutionary and ecological forces associated with these fundamental determinates of infection shape variation in parasite host breadth and host infection status. Here, I focus on a community of vector-borne avian Haemosporida parasites among suburban birds of Chicago, IL. These parasites exhibit strong variation in their distribution among available hosts, and provide an ideal system to investigate factors that structure parasite-host interactions. I find that while a vector-imposed encounter rate explains variation in the total prevalence of Plasmodium parasites among host species, it does not account for variation in the relationships of individual Plasmodium taxa with different host species. Instead, host species that are more closely related phylogenetically share more parasites. In addition, I present evidence for a trade-off between different parasite host breadth strategies. Specialized Haemosporida taxa reach higher prevalence in their sole host species than generalist Haemosporida taxa, which also infected other host species. In addition, specialists achieved higher prevalence on older host individuals suggesting that they can persist in their hosts longer than generalists. There was no relationship between host breadth and the density of infected hosts. This suggests that specialists infect the same number of hosts as generalists, and compensate for their narrower host ranges by achieving higher prevalence on more abundant hosts. Cumulatively, my dissertation highlights the role that evolutionary forces between the host and parasite play in delimiting the host ranges of vector-borne parasites
Unstructured Finite Element Mesh Decimation for Real Time Hurricane Storm Surge Forecasting
Motivation: Provide real time decision support
Emergency mangers are interested inâŠ
When will the water rise?
What height will it get?
How long will it stay?
Who will be impacted?
Will mesh decimation give accurate results in order to predict forecasted water levels for storms in a faster time frame than is currently used by larger meshes
Development of a High-Resolution, Wind-Wave, Tide, and Hurricane Storm Surge Model for Southern Mississippi
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv
Hydrodynamic Assessment of Natural and Nature-Based Features for Escatawpa River and Grand Bay in the Northern Gulf of Mexico
This presentation showcases a hydrodynamic assessment of natural and nature-based features (NNBFs) for the Pascagoula River, the Escatawpa River and Grand Bay, located along the Mississippi coast of the northern Gulf of Mexico. Two separate NNBF projects are being considered to: (1) restore the historical footprint (ca. 1848) of Grand Batture Island for coastal protection purposes; and (2) reconnect the hydraulics between the Escatawpa River and Grand Bay for ecosystem services purposes. The intended coastal protection benefits of the first project include buffering agency to wave attack and attenuation of storm surge with the restored island. The intended ecosystem services benefits of the second project include replenishment of sediments to the salt marsh via increased hydroperiod (duration of tidal inundation) and availability for sediment accumulation. Astronomic tide and storm surge simulations are performed with the advanced circulation (ADCIRC) plus simulating waves nearshore (+SWAN) model to evaluate the hydrodynamic impact of the NNBF projects (Image). The simulated hydrodynamics are assessed firstly in terms of storm surge and waves for the open coast with and without the restoration of Grand Batture Island (Passeri et al., 2015), and secondly for tidal datums and inundation extent for the salt marsh with and without the hydraulic reconnection of the Escatawpa River with Grand Bay (Alizad et al., 2018). A key outcome from the analysis is the interconnectedness of the hydrodynamics within the system, where the implementation of the NNBFs results in local and non-local impacts. The numerical modeling approach with high-resolution feature definition at a system-wide scale affords such methodical evaluation of NNBFs for ecosystem restoration
Expression of selected pathway-marker genes in human urothelial cells exposed chronically to a non-cytotoxic concentration of monomethylarsonous acid
AbstractBladder cancer has been associated with chronic arsenic exposure. Monomethylarsonous acid [MMA(III)] is a metabolite of inorganic arsenic and has been shown to transform an immortalized urothelial cell line (UROtsa) at concentrations 20-fold less than arsenite. MMA(III) was used as a model arsenical to examine the mechanisms of arsenical-induced transformation of urothelium. A previous microarray analysis revealed only minor changes in gene expression at 1 and 2 months of chronic exposure to MMA(III), contrasting with substantial changes observed at 3 months of exposure. To address the lack of information between 2 and 3 months of exposure (the critical period of transformation), the expression of select pathway marker genes was measured by PCR array analysis on a weekly basis. Cell proliferation rate, anchorage-independent growth, and tumorigenicity in SCID mice were also assessed to determine the early, persistent phenotypic changes and their association with the changes in expression of these selected marker genes. A very similar pattern of alterations in these genes was observed when compared to the microarray results, and suggested that early perturbations in cell signaling cascades, immunological pathways, cytokine expression, and MAPK pathway are particularly important in driving malignant transformation. These results showed a strong association between the acquired phenotypic changes that occurred as early as 1â2 months of chronic MMA(III) exposure, and the observed gene expression pattern that is indicative of the earliest stages in carcinogenesis
Stochastic Search Methods for Mobile Manipulators
Mobile manipulators are a potential solution to the increasing need for additional flexibility and mobility in industrial applications. However, they tend to lack the accuracy and precision achieved by fixed manipulators, especially in scenarios where both the manipulator and the autonomous vehicle move simultaneously. This paper analyzes the problem of dynamically evaluating the positioning error of mobile manipulators. In particular, it investigates the use of Bayesian methods to predict the position of the end-effector in the presence of uncertainty propagated from the mobile platform. The precision of the mobile manipulator is evaluated through its ability to intercept retroreflective markers using a photoelectric sensor attached to the end-effector. Compared to a deterministic search approach, we observed improved robustness with comparable search times, thereby enabling effective calibration of the mobile manipulator
Improvements in Attention and Cardiac Autonomic Modulation After a 2-Weeks Sprint Interval Training Program: A Fidelity Approach
[EN] This study aimed to: (1) investigate the influence of a 2-weeks sprint interval training (SIT)
program on aerobic capacity, cardiac autonomic control, and components of attention
in young healthy university students; and (2) to ascertain whether training fidelity would
influence these adaptations. One hundred and nine participants were divided into an
experimental (EG) and control (CG) groups. The EG performed a SIT program that
consisted of 6 sessions of 4 Ă 30 s âall-outâ efforts on a cycle ergometer, interspersed
with active rests of 4 min. The criterion for fidelity was achieving >90% of estimated
maximum heart rate (HR) during sprint bouts. After analyses, the EG was divided into
HIGH (n = 26) and LOW (n = 46) fidelity groups. Components of attention were assessed
using the Attention Network Test (ANT). Aerobic capacity (VO2max) was estimated while
the sum of skinfolds was determined. Autonomic control of HR was assessed by means
of HR variability (HRV) and HR complexity at rest and during ANT. Both HIGH and LOW
significantly increased aerobic capacity, vagal modulation before and during ANT, and
executive control, and decreased body fatness after SIT (p < 0.05). However, only
participants from HIGH showed an increase in HR complexity and accuracy in ANT
when compared to LOW (p < 0.05). Two weeks of SIT improved executive control, body
fatness, aerobic fitness, and autonomic control in university students with better results
reported in those individuals who exhibited high fidelity.AdS, AM, and SD enjoy a PROSUP-CAPES grant. DB enjoys a productivity in research grant from CNPq.CNPq (Brazil) (process number 486116/2013-1) supported this project. AdS, SD, and AM were supported by a PROSUP grant from CAPES (Brazil). SB-F is supported by a doctoral fellowship awarded by ANII (Uruguay). DB was supported by a productivity research grant from CNPq (Brazil). We would like to thank all participants for their collaboration and LEEFSâs laboratory staff (Giseli Kelly de Melo Oliveira Gomes, Alessandra Matida) for their assistance during data collection. The authors declare that the results of the study are presented clearly, honestly, and without fabrication, falsification, or inappropriate data manipulation
Improvements in attention and cardiac autonomic modulation after a 2-weeks sprint interval training program: a fidelity approach
This study aimed to: (1) investigate the influence of a 2-weeks sprint interval training (SIT) program on aerobic capacity, cardiac autonomic control, and components of attention in young healthy university students; and (2) to ascertain whether training fidelity would influence these adaptations. One hundred and nine participants were divided into an experimental (EG) and control (CG) groups. The EG performed a SIT program that consisted of 6 sessions of 4 x 30 s "all-out" efforts on a cycle ergometer, interspersed with active rests of 4 min. The criterion for fidelity was achieving >90% of estimated maximum heart rate (HR) during sprint bouts. After analyses, the EG was divided into HIGH (n = 26) and LOW(n = 46) fidelity groups. Components of attention were assessed using the Attention Network Test (ANT). Aerobic capacity (VO(2)max) was estimated while the sum of skinfolds was determined. Autonomic control of HR was assessed by means of HR variability (HRV) and HR complexity at rest and during ANT. Both HIGH and LOW significantly increased aerobic capacity, vagal modulation before and during ANT, and executive control, and decreased body fatness after SIT (p < 0.05). However, only participants from HIGH showed an increase in HR complexity and accuracy in ANT when compared to LOW (p < 0.05). Two weeks of SIT improved executive control, body fatness, aerobic fitness, and autonomic control in university students with better results reported in those individuals who exhibited high fidelity
The Dynamic Effects of Sea Level Rise on Low-Gradient Coastal Landscapes: A Review
Coastal responses to sea level rise (SLR) include inundation of wetlands, increased shoreline erosion, and increased flooding during storm events. Hydrodynamic parameters such as tidal ranges, tidal prisms, tidal asymmetries, increased flooding depths and inundation extents during storm events respond nonadditively to SLR. Coastal morphology continually adapts toward equilibrium as sea levels rise, inducing changes in the landscape. Marshes may struggle to keep pace with SLR and rely on sediment accumulation and the availability of suitable uplands for migration. Whether hydrodynamic, morphologic, or ecologic, the impacts of SLR are interrelated. To plan for changes under future sea levels, coastal managers need information and data regarding the potential effects of SLR to make informed decisions for managing human and natural communities. This review examines previous studies that have accounted for the dynamic, nonlinear responses of hydrodynamics, coastal morphology, and marsh ecology to SLR by implementing more complex approaches rather than the simplistic âbathtubâ approach. These studies provide an improved understanding of the dynamic effects of SLR on coastal environments and contribute to an overall paradigm shift in how coastal scientists and engineers approach modeling the effects of SLR, transitioning away from implementing the âbathtubâ approach. However, it is recommended that future studies implement a synergetic approach that integrates the dynamic interactions between physical and ecological environments to better predict the impacts of SLR on coastal systems
The Dynamic Effects of Sea Level Rise on LowâGradient Coastal Landscapes: A Review
Coastal responses to sea level rise (SLR) include inundation of wetlands, increased shore-line erosion, and increased flooding during storm events. Hydrodynamic parameters such as tidal ranges, tidal prisms, tidal asymmetries, increased flooding depths and inundation extents during storm events respond non additively to SLR. Coastal morphology continually adapts toward equilibrium as sea levels rise, inducing changes in the landscape. Marshes may struggle to keep pace with SLR and rely on sediment accumulation and the availability of suitable uplands for migration. Whether hydrodynamic, morphologic, or ecologic, the impacts of SLR are interrelated. To plan for changes under future sea lev-els, coastal managers need information and data regarding the potential effects of SLR to make informed decisions for managing human and natural communities. This review examines previous studies that have accounted for the dynamic, nonlinear responses of hydrodynamics, coastal morphology, and marsh ecol-ogy to SLR by implementing more complex approaches rather than the simplistic âbathtubâ approach. These studies provide an improved understanding of the dynamic effects of SLR on coastal environments and contribute to an overall paradigm shift in how coastal scientists and engineers approach modeling the effects of SLR, transitioning away from implementing the âbathtubâ approach. However, it is recommended that future studies implement a synergetic approach that integrates the dynamic interactions between physical and ecological environments to better predict the impacts of SLR on coastal systems
- âŠ