213 research outputs found

    Bilateral Sequential Lung Transplantation

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    Maturation of the gilt\u27s uterus before puberty: response to progesterone at different ages

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    We determined the age at which progesterone induced certain responses in the gilt\u27s uterus. The prepubertal maturation permitting each response is being studied currently with the intent of using the information to develop methods to improve litter size in pigs, perhaps by identifying markers for uterine function that could be used before gilts enter the breeding herd.; Swine Day, Manhattan, KS, November 16, 199

    Live-Fly, Large-Scale Field Experimentation for Large Numbers of Fixed-Wing UAVs

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    In this paper, we present extensive advances in live-fly field experimentation capabilities of large numbers of fixed-wing aerial robots, and highlight both the enabling technologies as well as the challenges addressed in such large-scale flight operations. We showcase results from recent field tests, including the autonomous launch, flight, and landing of 50 UAVs, which illuminate numerous operational lessons learned and generate rich multi-UAV datasets. We detail the design and open architecture of the testbed, which intentionally leverages low-cost and open-source components, aimed at promoting continued advances and alignment of multi-robot systems research and practice

    Birth weight threshold for identifying piglets at-risk for preweaning mortality

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    Citation: Feldpausch, J. A., Jourquin, J., Bergstrom, J. R., Bokenkroger, C. D., Nelssen, J. L., Ritter, M. J., . . . Gonzalez, J. M. (2016). Birth weight threshold for identifying piglets at-risk for preweaning mortality. Journal of Animal Science, 94, 34-34. doi:10.2527/msasas2016-074The association of piglet birth weight (BtW) with early-life mortality risk is strongly supported by research of numerous studies reporting decreased preweaning piglet mortality as individual piglet BtW increases. The purpose of the present analysis was to identify a BtW threshold associated with reduced odds of preweaning survival. Observations from 2 studies with a total of 4068 piglets originating from 394 litters on 4 different commercial farms (3 European, 1 U.S.) were compiled for meta-analysis. Overall preweaning mortality rate across all farms was 12.2%. Data used in the analysis was weight of piglets within 24 h of birth and their corresponding survival outcome (dead or live) by weaning at 3 to 4 wk of age. A mixed effects logistic regression model was fit to estimate the probability of preweaning mortality based on BtW. A random effect of study was included to account for overall differences in mortality between the 2 studies. A piecewise linear predictor was selected to best represent the drastic decrease in preweaning mortality found as BtW increased in the range of 0.5 to 1.0 kg and the less extreme change in preweaning mortality observed for changes in weight above 1.0 kg. The model change point was determined by comparing model fit for BtW ranging from 0.5 kg to 2.0 kg based on maximizing the likelihood. A linear predictor equation was also generated to estimate the associated preweaning mortality probability associated with every 50 g of piglet BtW. Results indicated a 1.11 kg BtW change point in the log odds of piglet preweaning mortality, thus, implicating that every incremental change in BtW below 1.11 kg has a greater impact on mortality risk than incremental changes in BtW above 1.11 kg. Among the farms in this analysis, 14.9% of all piglets had BtW < 1.11 kg. These findings imply that interventions targeted at increasing the BtW of piglets having BtW less than 1.11 kg have tremendous potential to improve piglet preweaning survivability. A large percentage of the neonatal pig population falls below this weight threshold, and postnatal management strategies to decrease neonatal mortality should be directed toward these at-risk piglets

    Physics-Based Modelling and Simulation of Multibeam Echosounder Perception for Autonomous Underwater Manipulation

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    17 USC 105 interim-entered record; under review.The article of record as published may be found at https://doi.org/10.3389/frobt.2021.706646One of the key distinguishing aspects of underwater manipulation tasks is the perception challenges of the ocean environment, including turbidity, backscatter, and lighting effects. Consequently, underwater perception often relies on sonar-based measurements to estimate the vehicle’s state and surroundings, either standalone or in concert with other sensing modalities, to support the perception necessary to plan and control manipulation tasks. Simulation of the multibeam echosounder, while not a substitute for in-water testing, is a critical capability for developing manipulation strategies in the complex and variable ocean environment. Although several approaches exist in the literature to simulate synthetic sonar images, the methods in the robotics community typically use image processing and video rendering software to comply with real-time execution requirements. In addition to a lack of physics-based interaction model between sound and the scene of interest, several basic properties are absent in these rendered sonar images–notably the coherent imaging system and coherent speckle that cause distortion of the object geometry in the sonar image. To address this deficiency, we present a physics-based multibeam echosounder simulation method to capture these fundamental aspects of sonar perception. A point-based scattering model is implemented to calculate the acoustic interaction between the target and the environment. This is a simplified representation of target scattering but can produce realistic coherent image speckle and the correct point spread function. The results demonstrate that this multibeam echosounder simulator generates qualitatively realistic images with high efficiency to provide the sonar image and the physical time series signal data. This synthetic sonar data is a key enabler for developing, testing, and evaluating autonomous underwater manipulation strategies that use sonar as a component of perception.This research was performed while the author held an NRC Research Associateship award at Field Robotics Laboratory, Naval Postgraduate Schoo

    The utility of 6-minute walk distance in predicting waitlist mortality for lung transplant candidates.

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    BACKGROUND The lung allocation score (LAS) has led to improved organ allocation for transplant candidates. At present, the 6-minute walk distance (6MWD) is treated as a binary categorical variable of whether or not a candidate can walk more than 150 feet in 6 minutes. In this study, we tested the hypothesis that 6MWD is presently under-utilized with respect to discriminatory power, and that, as a continuous variable, could better prognosticate risk of waitlist mortality. METHODS A retrospective cohort analysis was performed using the Organ Procurement and Transplantation Network/United Network for Organ Sharing (OPTN/UNOS) transplant database. Candidates listed for isolated lung transplant between May 2005 and December 2011 were included. The population was stratified by 6MWD quartiles and unadjusted survival rates were estimated. Multivariable Cox proportional hazards modeling was used to assess the effect of 6MWD on risk of death. The Scientific Registry of Transplant Recipients (SRTR) Waitlist Risk Model was used to adjust for confounders. The optimal 6MWD for discriminative accuracy in predicting waitlist mortality was assessed by receiver-operating characteristic (ROC) curves. RESULTS Analysis was performed on 12,298 recipients. Recipients were segregated into quartiles by distance walked. Waitlist mortality decreased as 6MWD increased. In the multivariable model, significant variables included 6MWD, male gender, non-white ethnicity and restrictive lung diseases. ROC curves discriminated 6-month mortality was best at 655 feet. CONCLUSIONS The 6MWD is a significant predictor of waitlist mortality. A cut-off of 150 feet sub-optimally identifies candidates with increased risk of mortality. A cut-off between 550 and 655 feet is more optimal if 6MWD is to be treated as a dichotomous variable. Utilization of the LAS as a continuous variable could further enhance predictive capabilities

    Modeling and Analysis of Effective Ways for Improving the Reliability of Second-hand Products Sold with Warranty

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    Often, customers are uncertain about the performance and durability of the used/second-hand products. The warranties play an important role in reassuring the buyer. Offering the warranty implies that the dealer incurs additional costs to service any claims made by the customers. Reducing warranty costs is an issue of great interest to dealers. One way of improving the reliability and reducing the warranty servicing cost for second-hand items is through actions such as overhaul and upgrade which are carried out by the dealer or a third party. Improving actions allow the dealer to offer better warranty terms and to sell the item at a higher price. This paper deals with two effective approaches (virtual age approach and screening test approach) to decide on the reliability improvement strategies for second-hand products sold under various warranty policies (failure-free, rebate warranty, and a combination of free replacement and lump sum). A numerical example illustrates that from a dealer’s point of view, it is beneficial to carry out an improvement action only if the reduction in the warranty servicing cost is greater than the extra cost incurred due to this improvement action

    Association of Dietary Factors with Presence and Severity of Tinnitus in a Middle-Aged UK Population

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    Objective The impact of dietary factors on tinnitus has received limited research attention, despite being a considerable concern among people with tinnitus and clinicians. The objective was to examine the link between dietary factors and presence and severity of tinnitus. Design This study used the UK Biobank resource, a large cross-sectional study of adults aged 40–69. 171,722 eligible participants were asked questions specific to tinnitus (defined as noises such as ringing or buzzing in the head or ears). Dietary factors included portions of fruit and vegetables per day, weekly fish consumption (oily and non-oily), bread type, cups of caffeinated coffee per day, and avoidance of dairy, eggs, wheat and sugar. We controlled for lifestyle, noise exposure, hearing, personality and comorbidity factors. Results Persistent tinnitus, defined as present at least a lot of the time, was elevated with increased: (i) fruit/vegetable intake (OR = 1.01 per portion/day), (ii) bread (wholemeal/wholegrain, OR = 1.07; other bread, 1.20) and (iii) dairy avoidance (OR = 1.27). Persistent tinnitus was reduced with: (i) fish consumption (non-oily, OR = 0.91; oily, 0.95), (ii) egg avoidance (OR = 0.87) and (iii) caffeinated coffee consumption (OR = 0.99 per cup/day). Reports of “bothersome” tinnitus (moderate-severe handicap) increased with wholemeal/wholegrain bread intake (OR = 0.86). Reports of less frequent transient tinnitus increased with dairy avoidance (OR = 1.18) and decreased with caffeinated coffee (OR = 0.98 per cup/day) and brown bread (OR = 0.94). Conclusions This is the first population study to report the association between dietary factors and tinnitus. Although individually dietary associations are mostly modest, particular changes in diet, such as switching between foodstuffs, may result in stronger associations. These findings offer insights into possible dietary associations with tinnitus, and this may be useful when discussing management options in combination with other lifestyle changes and therapies

    Neurobehavioral Functioning and Survival Following Lung Transplantation

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    Neurobehavioral functioning is widely recognized as being an important consideration in lung transplant candidates, but little is known about whether these factors are related to clinical outcomes. The present study examined the relationship of neurobehavioral functioning, including measures of executive function and memory, depression, and anxiety, to long-term survival among lung transplant recipients

    Emergency department spirometric volume and base deficit delineate risk for torso injury in stable patients

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    BACKGROUND: We sought to determine torso injury rates and sensitivities associated with fluid-positive abdominal ultrasound, metabolic acidosis (increased base deficit and lactate), and impaired pulmonary physiology (decreased spirometric volume and PaO(2)/FiO(2)). METHODS: Level I trauma center prospective pilot and post-pilot study (2000–2001) of stable patients. Increased base deficit was < 0.0 in ethanol-negative and ≤ -3.0 in ethanol-positive patients. Increased lactate was > 2.5 mmol/L in ethanol-negative and ≥ 3.0 mmol/L in ethanol-positive patients. Decreased PaO(2)/FiO(2 )was < 350 and decreased spirometric volume was < 1.8 L. RESULTS: Of 215 patients, 66 (30.7%) had a torso injury (abdominal/pelvic injury n = 35 and/or thoracic injury n = 43). Glasgow Coma Scale score was 14.8 ± 0.5 (13–15). Torso injury rates and sensitivities were: abdominal ultrasound negative and normal base deficit, lactate, PaO(2)/FiO(2), and spirometric volume – 0.0% & 0.0%; normal base deficit and normal spirometric volume – 4.2% & 4.5%; chest/abdominal soft tissue injury – 37.8% & 47.0%; increased lactate – 39.7% & 47.0%; increased base deficit – 41.3% & 75.8%; increased base deficit and/or decreased spirometric volume – 43.8% & 95.5%; decreased PaO(2)/FiO(2 )– 48.9% & 33.3%; positive abdominal ultrasound – 62.5% & 7.6%; decreased spirometric volume – 73.4% & 71.2%; increased base deficit and decreased spirometric volume – 82.9% & 51.5%. CONCLUSIONS: Trauma patients with normal base deficit and spirometric volume are unlikely to have a torso injury. Patients with increased base deficit or lactate, decreased spirometric volume, decreased PaO(2)/FiO(2), or positive FAST have substantial risk for torso injury. Increased base deficit and/or decreased spirometric volume are highly sensitive for torso injury. Base deficit and spirometric volume values are readily available and increase or decrease the suspicion for torso injury
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