136879 research outputs found
Sort by
Influence of Dietary Saccharomyces cerevisiae Fermentation Product on Markers of Inflammation and Cartilage Metabolism in Young Exercising Horses Challenged with Intra-Articular Lipopolysaccharide
No full textThe objective was to evaluate dietary Saccharomyces cerevisiae fermentation product (SCFP) on joint inflammation and cartilage metabolism in exercising yearlings challenged with intra-articular lipopolysaccharide (LPS), hypothesizing SCFP (TruEquine��C, Diamond V Mills, Inc.) would ameliorate inflammation and increase cartilage metabolism. Thirty Quarter Horse yearlings were stratified by bodyweight (BW), age, sex, and assigned to (n =10/dietary treatment): control (0), 46, or 92 mg/kg BW/d SCFP. Treatments were top-dressed to 1% BW concentrate. Horses were stalled, offered ad libitum Coastal bermudagrass hay, and exercised for 30 min/d, 5 d/wk. Every 21 d, wither height (WH), hip height (HH), heart girth (HG), body length (BL), and BW were obtained. On d 46, horses underwent an LPS challenge with each radial carpal joint receiving 0.8 mL of a 0.5 ng LPS solution or sterile lactated Ringer���s solution (LRS). Synovial fluid was collected pre (h 0), and 6, 12, 24, and 336 h post-injection, and analyzed for prostaglandin E2 (PGE2), carboxypropeptide of type II collagen (CPII) and collagenase cleavage neopeptide (C2C) via ELISA, and chemokines (CCL2, and CCL11) and cytokines (TNF�� and IL-10) via multiplex platform. Rectal temperature (RT), heart rate (HR), respiration rate (RR), and carpal circumference (CC) were recorded prior to arthrocentesis. Data were analyzed using MIXED procedure of SAS. By d 56, growth parameters increased (P < 0.01) where control had a greater increase in BW than SCFP groups (P < 0.01). Clinical parameters were uninfluenced by diet (P ��� 0.29) but varied over time (P ��� 0.03). Treatments didn���t influence CPII, C2C, CPII:C2C (P ��� 0.46) or logPGE2, logCCL2, CCL11, and logIL-10 (P ��� 0.23). There was an interaction for CCL11 (P = 0.04) where control was greater than SCFP groups at h 6. Furthermore, logIL-10 had an interaction where 46 mg/kg was lower at h 12 compared to control and 92 mg/kg (P = 0.05). There was a treatment effect for TNF�� (P = 0.04) where 92 mg/kg was lower than 46 mg/kg and tended to be lower than control. Although SCFP didn���t influence cartilage metabolism or logPGE2, SCFP may ameliorate inflammatory cytokines and chemokines following an acute, intra-articular insult
Hydro-Mechanical Study of Two Shrink-Swell Soils Under Hydrating and Shearing
No full textShrink-swell soils are a type of soil that expands and contracts in response to changes in moisture content. The soil is widely spread across the world and has become a prevalent geotechnical practice problem. The uneven shrink and swell behavior of shrink-swell soil causes damage to infrastructure and cost millions to repair. Most mechanical tests on shrink-swell soils have been conducted under oedometer conditions which restrict lateral movement. A limitation of such approach is that lateral soil strains are possible in practical problems. Triaxial tests, under controlled shear and confinement conditions, can represent better actual soil conditions. Very limited research has been conducted involving soil shearing and soaking behaviors under triaxial conditions, and they were related to low to intermediate expansive soils. Our research is pioneering in this area, exploring this feature of soil behavior of high to very high expansive clays under triaxial conditions. This study focuses on examining the behavior of unsaturated shrink-swell soils during shearing and soaking, aiming to offer reference soil data for civil structures like foundations and retaining walls built on these soils. It specifically investigates two types of shrink-swell soils, Texas natural soil and MX-80 bentonite, using an updated triaxial test protocol in the laboratory. The triaxial test results for Texas natural soil are utilized to validate the Barcelona Basic Model (BBM) in numerical modeling. Additionally, this dissertation includes a numerical study exploring the effect of horizontal swelling pressure on retaining wall structures in shrink-swell soil environments. The goal is to apply theoretical understanding of shrink-swell soils to address real-world geotechnical challenges. The behaviors of two shrink-swell soils under shearing and soaking are discussed and compared. The effects of stress level (particular deviatoric stress) on unsaturated shrink-swell soil volume change and final shear strength when subjected to soaking are investigated. The study also concludes how varying swelling properties of soils affect their behavior under shearing and soaking in different triaxial test conditions. BBM successfully replicates the behavior of Texas natural soil in terms of deviator stress and volume change under triaxial conditions. These insights contribute to setting benchmarks for shearing and soaking shear strength of shrink-swell soils in triaxial conditions and expanding the database available for the Texas region, aiding in foundation design. Moreover, the BBM helps to understand the distribution of horizontal swelling pressure on retaining walls, leading to simplified methods for inclusion in retaining wall design standards
A Characterization of the Vertical Structure and Mixing of the Eastern Mediterranean Sea
No full textObservational data collected by THEMO (The Texas A&M - University of Haifa Eastern Mediterranean Observatory) is used to characterize the seasonal variability of the water-column to understand the vertical structure and vertical mixing of the Levantine Basin in the Eastern Mediterranean Sea. Previous studies have shown the marginal Eastern Mediterranean Sea is characterized by hypersaline waters, strong water-column stratification, and regular seasonal atmospheric patterns. THEMO is composed of two surface buoys located off the coast of Haifa, Israel: one shallow buoy (water depth of 125 m; 10 km from shore) in the coastal zone of the Levantine Basin, one deep buoy (water depth of 1430 m; 60 km from shore), and one StandAlone McLane Moored Profiler (MMP), which is deployed close to the deep buoy. These instruments and buoys provide in-situ near real-time subsurface physical oceanographic observations and atmospheric observations of the Eastern Mediterranean Sea. The objectives of this research are: 1) to characterize and identify the processes that force the seasonality of the surface mixed layer depth, 2) to quantify the mechanisms that drive the hydrographic variability of the upper (surface to 1400 m depth) water-column, and 3) to categorize the stability processes of the Eastern Mediterranean Sea upper water-column using Turner Angle (Tu). Results show that the mixed layer depth varies seasonality from 250 m in Winter to less than 85 m in non-Winter months and is correlated with relatively stronger winter wind speeds (average of 7.12 m/s (Winter) to 4 m/s (non-Winter)). The upper 100 m of the water-column also experiences warming of 2 degrees C during Winter due to enhanced downward mixing of warm surface water with cooler subsurface water. Statistical analysis using empirical orthogonal functional (EOF) analysis shows that outside Winter months, variance in the principal component time-series is most correlated with the geostrophic current direction and accounts for about 50% of the total variance of water-column temperature and salinity. Characterization of water-column stability shows stable waters (-45 degrees < Tu < 45 degrees), i.e., no overturning, are most likely to occur in the upper 200 m of the water-column, and double diffusive mixing through salt fingering occur in waters below the mixed layer depth. The depth of salt fingering and stability are similar to other areas of the deep Eastern Mediterranean Sea and mid-latitude marginal seas of the world ocean
Development and Verification of a Nuclear Forensics Methodology for the Attribution of Plutonium Using Data Science Methods
No full textAn advantage the global community has in preventing nuclear terrorism is the difficulty for a nonstate actor to procure special nuclear material (SNM). The regulation of SNM is essential in stymying adversaries. A nuclear forensics methodology, able to determine the provenance of SNM, like plutonium (Pu), will aid the international community in deterring nuclear smuggling. If Pu is recovered outside of regulatory control, an attribution capability would help inform conventional investigators. In both cases of theft and state hand-off of Pu, a guarantee that an offending party would be discovered and punished could force preemptive abandonment of any planned misdeeds.
The goal of this research was to develop and verify a nuclear forensics methodology for attributing unknown separated Pu samples using machine learning techniques. The methodology needed to be capable of identifying the following three attributes: the reactor-type that produced the Pu sample, the burnup of the irradiated uranium fuel that produced the Pu sample, and the time since irradiation (TSI). The methodology also needed to be robust enough to attribute samples that contain a mixture of Pu from multiple different reactor sources. A set of isotope ratios was used as the forensics signature and the training of the machine learning models utilized data from a library of Monte Carlo reactor neutronic and fuel burnup simulations. Lastly, the methodology needed to be validated by demonstrating that it could successfully attribute physical Pu samples.
Research proceeded in three main parts. First, machine learning models suitable for this application were identified, and were then trained and tested for attributing single reactor type Pu samples to assess feasibility. Second, the methodology was validated with a Pu sample separated from low enriched uranium dioxide (LEUO2) irradiated in a thermal neutron flux spectrum. Third, the machine learning methodology was adapted to attribute samples that were sourced from multiple reactor types. Additionally, a method for estimating the machine learning models��� prediction uncertainty that considered the Pu sample���s measurement uncertainty was investigated. Ultimately, all main objectives were successfully achieved. This is the first example in open literature of a methodology for attributing mixed reactor type Pu samples
NAC1 Restrains T Cell Memory Formation through Metabolism Regulation During Viral Infection
No full textOur recent studies uncovered the important roles of nucleus accumbens-associated protein 1 (NAC1), a transcriptional co-factor, in regulating the activity of regulatory T cells, and antitumor immunity. Little is known about how NAC1 interrupts T cell memory, despite its significance in the host's defensive response to invading pathogens. Many factors interrupt T cell memory formation, such as transcriptional factors, virus types, cell metabolism, and autophagic status.
In the current study, we analyzed T cells from wild-type (WT) and NAC1-deficient (-/-) mice and observed that NAC1 is essential for both CD8��� and CD4��� T cell metabolism including glycolysis and oxidative phosphorylation and supports T cell survival in vitro.
In vivo, compared with wild-type (WT) mice, NAC1-/- mice exhibit a slow decrease of viral antigen (Ag)-specific CD8��� T cells. Additionally, we observed that the NAC1-/- mice demonstrated a stronger memory formation of VACV-specific CD8��� T cells post-viral infection. Mechanically, we identified that compared with WT CD8��� T cells, the Interferon Regulatory Factor 4 (IRF4), a key transcription factor in T cell development, was highly expressed in NAC1-/- CD8��� T cells. For CD4��� T cells, we further demonstrated that deficiency of NAC1 downregulates glycolysis in CD4��� T cells through modulation of the AMPK-mTOR pathway. Moreover, loss of NAC1 reduces the expression of ROCK1, the phosphorylation and stabilization of BECLIN1. Furthermore, forced expression of ROCK1 in NAC1-/- CD4��� T cells results in the restoration of autophagy as well as the activity of the AMPK-mTOR pathway. In animal experiments, adoptively transferred NAC1-/- CD4��� T cells or NAC1-/- mice challenged with VACV show enhanced formation of the VACV-specific CD4��� memory T cells as compared with adoptively transferred WT CD4��� T cells or WT mice, but this enhancement of memory T cell formation can be abrogated by forced expression of ROCK1.
Overall, the results of this study reveal the novel role of NAC1 as a suppressor of T cell memory formation and imply that targeting NAC1 may be exploited as a new approach to promoting memory T cell development
Markov Duality and Asymptotics of Interacting Particle Systems
No full textWe propose novel algebraic methods to Markov dualities. The first method produces orthogonal polynomial dualities from the ������bialgebra structure of Drinfeld���Jimbo quantum groups. The ������structure allows for the construction of certain unitary symmetries, which imply the orthogonality of the duality functions. In the case of the quantum group Uq(gln+1), the result is a nested multivariate q���Krawtchouk duality for the n���species ASEP(q, ��). The method also applies to other quantized simple Lie algebras (e.g. so2n) and to stochastic vertex models. The second method constructs duality functions for integrable dynamic models. This method will be implemented on dynamic stochastic higher spin vertex models, where we prove the duality functions between the dynamic stochastic higher spin vertex models and non dynamic stochastic higher spin vertex models are the 3��2 functions. A degeneration of these duality functions is dual q���Krawtchouk polynomials, which agree with orthogonal polynomial dualities between ASEP and dynamic ASEP of Groenevelt���Wagenaar [1]. The method involves using the universal twister of Uq(sl2), viewed as a quasi���triangular, quasi���������Hopf algebra. The algebraic method is presented very generally and is expected to produce duality functions for other dynamic integrable models.
As probabilistic applications of the duality relations found, we provide the explicit contour integral formula of the q���shifted factorial moments (namely the q-analogue of the Pochhammer symbol) for the two���species q���TAZRP (totally asymmetric zero range process). We use those contour integral formulas to find the asymptotics of the two���point correlations. In addition, we also focus on the open symmetric exclusion process with parameter m (open SEP(m/2)). Based on duality relations, we prove that the hydrodynamic limit of the density profile for a d���dimensional open SEP(m/2) solves the (d + 1)���dimensional heat equation with certain initial condition and boundary condition. Last, as an application of the duality of dynamic six vertex model, we prove ii that the asymptotic fluctuations of the dynamic stochastic six vertex model with step initial conditions are governed by the Tracy���Widom distribution
Environmental Impacts on Precipitation-Anvil Relationships
No full textTropical anvil cloud area response to the environmental effects of increased greenhouse gas emission is expected to be a negative cloud feedback for regulating climate sensitivity, although the magnitude of the effect is highly uncertain. This feedback is hypothesized to be caused by tropical deep convection acting as an iris in which anvil cloud coverage and properties are altered allowing more longwave radiation to escape. Recent studies hypothesize that a temperature dependence of convective aggregation could act as a potential mechanism to increase precipitation efficiency at the expense of anvil area. In this study, a precipitating, deep convection cloud object database is created using Tropical Rainfall Measuring Mission satellite observations from 2003-2014 to assess foundational relationships between the environment and precipitation, anvil cloud, and convective aggregation.
Analysis of the largest and strongest storms that contribute the most to tropical anvil cloud area and precipitation shows that precipitation-anvil relationships are more sensitive to changes in moisture rather than temperature, primarily due to greater sensitivity of convective processes to mid-level moisture. Our proxy for convective aggregation, the number of heavy rain cores in the cloud, had the strongest correlation with mid-level moisture increases which was coupled with greater precipitation increases relative to anvil cloud area. As moisture increases, the fractional contribution of different cloud components in the cloud objects shift, with more cold convection area and a reduction in the fraction of thin anvil area. On a system scale, this analysis is consistent with the mechanism that suggests organization and aggregation of convection results in greater precipitation per unit area of anvil cloud
Essays on Hospital Performance
No full textThis dissertation consists of three essays that focus on hospital service quality and healthcare delivery performance issues. I provide insights on how hospital administrators can leverage hospital personnel, accreditation, and community outreach services to influence hospital performance.
The first essay provides empirical associations regarding impacts of the extent of use of midlevel providers (MLPs) on (i) hospital quality, as measured by the Triple Aim Performance (TAP) metrics, and (ii) hospital costs. Hospital administrators are shifting care delivery models toward an approach that uses more caregivers in the form of mid-level providers (MLPs), such as nurse practitioners, physician assistants, and clinical nurse specialists. To date, however, healthcare operations management (OM) literature remains ambiguous about longitudinal empirical associations between mid-level providers and hospital costs, quality, and other performance measures. This essay, by providing one of the first panel data analyses of midlevel provider impacts in general service hospitals, improves upon existing case studies found in the extant literature. I find that MLPs can improve hospital clinical quality, technical efficiency, and patient experience without impacting hospital costs.
The second essay analyzes associations of hospital accreditation with hospital technical efficiency. As the U.S. healthcare marketplace becomes more competitive, many hospitals face problems of communicating with potential patients about the process conformance of their services. Similarly, patients face uncertainty when choosing a hospital from which to obtain care. A possible solution to this problem involves a hospital obtaining an accreditation. Hospital accreditation is a publicly visible indicator that a hospital provides care and services that should meet a high standard, as defined by an accreditation body. Hospitals can use accreditation as a signal to potential patients to help reduce information asymmetry between the two parties. I contribute to healthcare OM literature by providing one of the first panel-based SFA analyses of associated impacts that hospital accreditation has with hospital efficiency. I find that hospital accreditation is associated with improved hospital technical efficiency, but this association is moderated by government efficiency mandate signals. Since obtaining and maintaining hospital accreditation is a resource intensive and expensive process for administrators, the findings give hospital administrators and other stakeholders useful knowledge that should help in the decision-making process of whether or not to obtain hospital accreditation.
The third essay examines the association that alignment between hospital community outreach services and community needs may have with hospital readmission and mortality rates. One of the tools hospital administrators may employ to potentially reduce readmissions and improve care quality is providing community outreach services within the surrounding community. Individuals��� health is largely determined, in part, in the geographic community and context that they live and/or work in. Community-based hospital outreach programs may serve to educate community members about the availability of care services at the hospital or inform recently discharged patients about proper post-discharge care. I investigate whether these community outreach programs are associated with reduced hospital readmissions and reduced mortality. Overall findings suggest that alignment between hospital community outreach services and community needs are not significantly associated with hospital readmission rates but may be associated with higher hospital mortality rates depending on how hospital community outreach services are operationalized
Atomic Boson Sampling in a Bose-Einstein Condensed Gas
No full textWe propose a multi-qubit Bose-Einstein-condensate (BEC) trap as a platform for studies of quantum statistical phenomena in many-body interacting systems. In particular, it could facilitate testing atomic boson sampling of the excited-state occupations and its quantum advantage over classical computing in a full, controllable and clear way. Contrary to a linear interferometer enabling Gaussian boson sampling of non-interacting non-equilibrium photons, the BEC trap platform pertains to an interacting equilibrium many-body system of atoms with established Bose���Einstein condensate. We discuss a basic model and the main features of such a multi-qubit BEC trap.
We describe boson sampling of interacting atoms from the noncondensed fraction of Bose-Einstein-condensed gas confined in a box trap with periodic boundary conditions. We explicitly show increasing apparent complexity of sampling probability patterns with changing the observational basis of excited atom states from the eigen-squeeze modes to more and more involved unitary mixtures of them. We calculate the characteristic function and statistics of atom numbers via newly found hafnian master theorem. Using Bloch-Messiah reduction, we find that interatomic interactions give rise to two equally important entities ��� eigen-squeeze modes and eigen-energy quasiparticles ��� whose interplay with sampling atom states determines quantum statistics of the BEC gas. We infer that two necessary ingredients of computational ���P-hardness, squeezing and interference, are self-generated in the BEC gas and, contrary to Gaussian boson sampling in linear interferometers, external sources of squeezed bosons are not required for observation of quantum advantage manifestations.
The focus of the dissertation is on the origin of the computational ���P-hard complexity and quantum advantage of atomic boson sampling due to interference and squeezing of the sampled atom states via their interplay with the eigen-squeeze modes and eigen-energy quasiparticles
Thermal Lethality Validation for Human Pathogenic Salmonella enterica on Chicken Feathers and Blood During Simulated Low-Temperature Rendering
No full textPoultry carcass offal rendering is the process in which poultry inedible and carcass waste materials are converted into high-quality protein meals such as poultry, feather, and blood meal, and other commercial byproducts through physical and chemical transformation using sustained heat application, moisture extraction, and fat separation. Nevertheless, the presence of pathogens in animal feed that have been linked to ingredients obtained from rendered products has raised concerns over the process���s capability to reduce food safety hazards to acceptable levels that might be transmitted to animal feeds. This study was conducted to validate the inactivation, and determine the death kinetics, of a thermotolerant human pathogenic Salmonella enterica in chicken feathers and blood during simulated low-temperature dry rendering conditions. Chicken feathers and blood were inoculated with Salmonella enterica serovar Senftenberg 775W and heated to 60, 70, or 80 ��C for 60, 20, and 5 min, respectively. Complete block design experiments were conducted and three samples for each product were processed at each time point and replicated three times (N=3). After thermal treatment, samples were serially diluted and selectively enumerated after incubating for 24 h at 37��C. Experimental data were log-transformed and the Geeraerd non-linear inactivation model was used for curve and data fitting with the Microsoft Excel Add-In software toolkit GInaFiT. The data analysis showed D-values and observed shoulder periods decreased with increase in processing temperature for both feathers and blood. D-values were 2.23��0.045, 0.66��0.135, and 0.29��0.0225 min for chicken feathers and 2.22��0.2, 0.46��0.0175, and 0.27��0.05 min for chicken blood at 60,70, and 80 ��C respectively. Secondary model analysis showed that the maximum inactivation rate was positively correlated with the processing temperature. Model predicted Kmax values calculated per minute were 1.05��0.07, 3.63��0.20, and 8.37��0.67 for chicken feathers, and 1.06��0.10, 5.06��0.20, and 8.53��1.10 for chicken blood at 60, 70, and 80 oC respectively. Study findings validated ability of low-temperature rendering conditions to significantly reduce Salmonella in poultry rendered product to below detectable values. They also provide rendering industry a supporting tool for food safety validation and food safety regulatory standards compliance