Mantle melting and intraplate volcanism due to self‐buoyant hydrous upwellings from the stagnant slab that are conveyed by small‐scale convection

The mechanisms sustaining basaltic continental intraplate volcanism remain controversial. Continental intraplate volcanism is often geographically associated with slab stagnation in the mantle transition zone (MTZ), for example, in eastern Asia, central Europe, and western North America. Using 2‐D geodynamic models, we here explore the role of the stagnation of a slab and an associated hydrous layer in the MTZ on the formation and evolution of intraplate volcanism. Due to the intrinsic buoyancy of the hydrous layer atop the stagnant slab, upwellings develop within a few million years and rise to ~410‐km depth. At these depths, they partly lose their intrinsic buoyancy due to dehydration and stall intermittently. However, they are readily entrained by sublithospheric small‐scale convection to reach the base of lithosphere, sustaining mantle melting and intraplate volcanism. Water contents of >0.3 wt.‐% in a ≥ 60‐km‐thick layer atop the slab are sufficient for an early (<~20 Myr) onset of melting to account for volcanism, for example, in NE China. Thus, significant amounts of hydrous materials are not expected to remain stable in the MTZ for geological timescales, consistent with geophysical estimates. To explain the geochemical signatures of the Cenozoic basaltic volcanism in northern China, a mixed composition of the hydrous layer, including an enriched mantle‐type and a hybrid depleted mid‐ocean ridge basalts mantle/high μ‐type component, is required

Anesthesiology Posters - 2019

Anesthesiology Postershttps://scholarlycommons.libraryinfo.bhs.org/research_education/1000/thumbnail.jp

Unmanned aerial vehicle based tree canopy characteristics measurement for precision spray applications

The critical components for applying the correct amount of agrochemicals are fruit tree characteristics such as canopy height, canopy volume, and canopy coverage. An unmanned aerial vehicle (UAV)-based tree canopy characteristics measurement system was developed using image processing approaches. The UAV captured images using a high-resolution red-green-blue (RGB) camera. A digital surface model (DSM) and a digital terrain model (DTM) were generated from the captured images. A tree canopy height map was generated from the subtraction of DSM and DTM. A total of 24 apple trees were randomly targeted to measure the canopy characteristics. Region of interest (ROI) was generated across the boundary of each targeted tree. The height of all pixels within each ROI was computed separately. The pixel with maximum height was considered as the height of the respective tree. For computing canopy volume, the sum of all pixel heights from individual ROI was multiplied by the square of ground sample distance (GSD) of 5.69 mm·pixel−1. A segmentation method was employed to calculate the canopy coverage of the individual trees. The segmented canopy pixel area was divided by the total pixel area within the ROI. The results showed an average relative error of 0.2 m(6.64%) while comparing automatically measured tree height with ground measurements. For tree canopy volume, a mean absolute error of 0.25 m3 and a root mean square error of 0.33 m3 were achieved. The study estimated the possible agrochemical requirement for spraying the fruit trees, ranging from 0.1 to 0.32 l based on tree canopy volumes. The overall investigations suggest that the UAV-based tree canopy characteristics measurements could be a potential tool to calculate the pesticide requirement for precision spraying applications in tree fruit orchards

A MAPAEKF-SLAM ALGORITHM WITH RECURSIVE MEAN AND COVARIANCE OF PROCESS AND MEASUREMENT NOISE STATISTIC

The most popular filtering method used for solving a Simultaneous Localization and Mapping is the Extended Kalman Filter. Essentially, it requires prior stochastic knowledge both the process and measurement noise statistic. In order to avoid this requirement, these noise statistics have been defined at the beginning and kept to be fixed for the whole process. Indeed, it will satisfy the desired robustness in the case of simulation. Oppositely, due to the continuous uncertainty affected by the dynamic system under time integration, this manner is strongly not recommended. The reason is, improperly defined noise will not only degrade the filter performance but also might lead the filter to divergence condition. For this reason, there has been a strong manner well-termed as an adaptive-based strategy that commonly used to equip the classical filter for having an ability to approximate the noise statistic. Of course, by knowing the closely responsive noise statistic, the robustness and accuracy of an EKF can increase. However, most of the existed Adaptive-EKF only considered that the process and measurement noise statistic are characteristically zero-mean and responsive covariances. Accordingly, the robustness of EKF can still be enhanced. This paper presents a proposed method named as a MAPAEKF-SLAM algorithm used for solving the SLAM problem of a mobile robot, Turtlebot2. Sequentially, a classical EKF was estimated using Maximum a Posteriori. However, due to the existence of unobserved value, EKF was also smoothed one time based on the fixed-interval smoothing method. This smoothing step aims to keep-up the derivation process under MAP creation. Realistically, this proposed method was simulated and compared to the conventional one. Finally, it has been showing better accuracy in terms of Root Mean Square Error (RMSE) of both Estimated Map Coordinate (EMC) and Estimated Path Coordinate (EPC).     

The Approaches to Increase Employees’ Loyalty: A Review on Employees’ Turnover Models

It is a widely acknowledged fact that retaining organizational employees is a critical challenge to many human resource managers, however, this relationship is said to be an important mechanisms through which socialization tactics influence commitment and turnover. From a managerial perspective, the attraction and retention of high-quality employees is more important today than ever before. A numbers of trends make it vital that firms acquire and retain human capital as it is known in human resource that turnover is the rate at which an employer gains and misplaces employees or how long employees tend to stay. Authors have pointed out that turnover is one of the most researched phenomenon in organizational behavior. Issues they need to consider may be in the areas of shrinking pool of entry-level workers, individual differences, use of temporary workers, productivity and competitiveness, retirement benefits and skills development. As it is typical for most studies on turnover, the focus is mainly on members leaving rather than entering the organization. High turnover is harmful to a company’s productivity if it involves skilled workers. Organizations are increasingly concerned about their capability to retain their key employees such as high performer and employees who make an important contribution to stimulate organization’s innovative behavior. Consequent upon this, this research seeks to review some of the past models with a view to understanding the trend and proffer recommendations to organizational policy makers in both public and private organization

Ventral Hernia Repairs: 10 year Single Institution Review at Thomas Jefferson University Hospital

Abstract Background Definitive repair of recurrent ventral hernias using abdominal wall reconstruction techniques is an essential tool in the armentarium for general and plastic surgeons. Ramirez 1 et al describes the “component separation” technique to mobilize the rectus-abdominus internal oblique and external oblique flap to correct the defect. The recurrence rate of incisional hernias increases to 20% after gastric bypass or extensive weight loss.2 The incidence of ventral hernias after failed recurrent hernia repair increases to 40%.3 It has been reported that utilizing the sliding myofascial flap repair technique, the recurrence rate was reduced to 8.5%.4 Materials and Methods This retrospective institutional study reviews 10 years of myofascial flap reconstruction 1996-2006 at TJUH. Several techniques and prosthetic materials (alloderm, permacol, vicryl, composix) were used in our institutional review by multiple surgeons in this time period. Our goal is to identify risk factors (i.e. smoking, diabetes, obesity, size of defect, peripheral vascular disease, enterocutaneous fistula, infection) that predict or categorize patients that are at increased risk for failure of primary repair, measure the complication rates (i.e. infection, recurrence, seroma, hematoma) and evaluate the techniques and long term effectiveness of several prosthetic materials. Results Three thousand twenty ventral hernia repairs were performed at TJUH between 1996 and 2006. Two thousand three hundred eighty three approximated the rectus abdominus primarily and of these 645 utilized a component separation technique. The recurrence rate for component separations was 18.5% and 83% for primary repairs. The average follow up was 5.49 years. Statistically significant risk factors (p\u3c0.05) for recurrence were obesity (BMI\u3e30 kg/m2), age\u3e65 years, male gender, preoperative infection and postoperative seroma. Conclusion Myofascial flaps are a safe, reliable therapy for recurrent ventral hernias that addresses the population of patients that have failed conventional primary closure and reduce the recurrence rates greater than 40 percent to 18.5 percent in the carefully selected patient population

How do people with chronic low back pain perceive specific and general exercise? A mixed methods survey

Purpose: Exercise prescriptions for chronic low back pain (CLBP) often utilize reductionistic, trunk-focused exercise aimed at addressing proposed pain mechanisms. It is unknown if the use of these trunk-focused exercises imply beliefs to people with CLBP about the rationale for their use (e.g., etiology), even without concurrent biomedical narratives. This study aimed to explore people's perceptions of specific and general exercise without an accompanying narrative when experiencing CLBP. Methods: An anonymous online survey was distributed. Mixed methods were utilized for analysis. Six-point Likert scales categorized people's beliefs about individual exercises. Open-ended questions were used to gather further beliefs which were then coded into themes. Results: People with CLBP perceived specific exercise as more beneficial than general exercise. Eight themes and five subthemes were defined. A high volume of positive beliefs were centered around strengthening the low back and abdominal musculature, emphasizing the importance of correct technique. Negative beliefs were held against spinal flexion and external load. Both positive and negative beliefs were underpinned by spinal/pelvic stability being important as well as certain exercises being achievable or not. Conclusion: This study demonstrated that people with CLBP consider specific exercises to be more beneficial than general exercises for CLBP. Specific exercises irrespective of an accompanying narrative can imply meaning about the intent of an exercise. Understanding this requires practitioners to be mindful when prescribing and communicating exercise

AED: An Anytime Evolutionary DCOP Algorithm

Evolutionary optimization is a generic population-based metaheuristic that can be adapted to solve a wide variety of optimization problems and has proven very effective for combinatorial optimization problems. However, the potential of this metaheuristic has not been utilized in Distributed Constraint Optimization Problems (DCOPs), a well-known class of combinatorial optimization problems prevalent in Multi-Agent Systems. In this paper, we present a novel population-based algorithm, Anytime Evolutionary DCOP (AED), that uses evolutionary optimization to solve DCOPs. In AED, the agents cooperatively construct an initial set of random solutions and gradually improve them through a new mechanism that considers an optimistic approximation of local benefits. Moreover, we present a new anytime update mechanism for AED that identifies the best among a distributed set of candidate solutions and notifies all the agents when a new best is found. In our theoretical analysis, we prove that AED is anytime. Finally, we present empirical results indicating AED outperforms the state-of-the-art DCOP algorithms in terms of solution quality.Comment: 9 pages, 6 figures, 2 tables. Appeared in the proceedings of the 19th International Conference on Autonomous Agents and Multi-Agent Systems (AAMAS 2020

Cerebral Blood Volume Changes During Radiotherapy May Predict Pseudoprogression versus Disease Progression for Patients with High Grade Glioma

https://openworks.mdanderson.org/sumexp21/1040/thumbnail.jp