Market Competition, Station Ownership, and Local Public Affairs Programming on Broadcast Television

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73441/1/j.1460-2466.2006.00320.x.pd

Tracking Aqueous Proton Transfer by Two-Dimensional Infrared Spectroscopy and ab Initio Molecular Dynamics Simulations.

Proton transfer in water is ubiquitous and a critical elementary event that, via proton hopping between water molecules, enables protons to diffuse much faster than other ions. The problem of the anomalous nature of proton transport in water was first identified by Grotthuss over 200 years ago. In spite of a vast amount of modern research effort, there are still many unanswered questions about proton transport in water. An experimental determination of the proton hopping time has remained elusive due to its ultrafast nature and the lack of direct experimental observables. Here, we use two-dimensional infrared spectroscopy to extract the chemical exchange rates between hydronium and water in acid solutions using a vibrational probe, methyl thiocyanate. Ab initio molecular dynamics (AIMD) simulations demonstrate that the chemical exchange is dominated by proton hopping. The observed experimental and simulated acid concentration dependence then allow us to extrapolate the measured single step proton hopping time to the dilute limit, which, within error, gives the same value as inferred from measurements of the proton mobility and NMR line width analysis. In addition to obtaining the proton hopping time in the dilute limit from direct measurements and AIMD simulations, the results indicate that proton hopping in dilute acid solutions is induced by the concerted multi-water molecule hydrogen bond rearrangement that occurs in pure water. This proposition on the dynamics that drive proton hopping is confirmed by a combination of experimental results from the literature

Robust Balancing for Bipedal Robot via Model Predictive Control

Robust balancing controllers are essential for bipedal robots to safely operate in real-world applications where human-robot interactions are a common practice. While the balancing controllers being developed are effective, they struggle when adjusting to untested motions and environments. Popular controllers commonly rely on heuristic techniques, and simplified models of the intended system, and are optimized to compute applicable joint inputs quickly. What they sacrifice in robustness, they often make up for in computational efficiency and speed. Here, the triple pendulum model is used as a unique method of simulating the dynamics of a bipedal robot in the 2-D saggital plane. The goal of this research is to develop a control architecture which can stabilize the triple pendulum in real time using the linear center of mass dynamics, and when introduced to random initial conditions, fluctuating stance heights and external disturbances. These objectives will be achieved via a model predictive control architecture, supplemented by the angular linear inverted pendulum model and an inverse dynamics function which computes the applicable low-level joint torques. Various optimization algorithms, most notably the nonlinear Newton's optimization and the nonlinear gradient descent algorithm, will also be tested with the intent of running in real-time. The initial algorithm design stage was completed in MATLAB and Python, before being implemented in the MuJoCo simulation system in Python for final testing. Most notably, the simplified model could be simulated for a prediction horizon of length 20 with a time-step of 0.05[s] (1[s] of look ahead time) with an average calculation time of 363.13[ms]. As was expected, the largest drawback to implementing the discussed control system is the computation time required for each call of the optimization program. That said, results show that implementing the MPC system would result in more stable overall performance, and creates a system which can enter new environments with little-to-no tuning while maintaining stability.No embargoAcademic Major: Mechanical Engineerin

Coinductive subtyping for abstract compilation of object-oriented languages into Horn formulas

In recent work we have shown how it is possible to define very precise type systems for object-oriented languages by abstractly compiling a program into a Horn formula f. Then type inference amounts to resolving a certain goal w.r.t. the coinductive (that is, the greatest) Herbrand model of f. Type systems defined in this way are idealized, since in the most interesting instantiations both the terms of the coinductive Herbrand universe and goal derivations cannot be finitely represented. However, sound and quite expressive approximations can be implemented by considering only regular terms and derivations. In doing so, it is essential to introduce a proper subtyping relation formalizing the notion of approximation between types. In this paper we study a subtyping relation on coinductive terms built on union and object type constructors. We define an interpretation of types as set of values induced by a quite intuitive relation of membership of values to types, and prove that the definition of subtyping is sound w.r.t. subset inclusion between type interpretations. The proof of soundness has allowed us to simplify the notion of contractive derivation and to discover that the previously given definition of subtyping did not cover all possible representations of the empty type

Switched capacitor charge pump voltage-controlled current source

This manuscript describes a switched-capacitor current source for applications such as driving high brightness LEDs and lasers. By introducing a third phase of operation into a two-phase charge pump DC-DC converter, the proposed design offers a potential solution to the excessive power typically consumed in regulating the diode or laser current. This results in a highly integrable voltage-to-current regulator

Examination of Fluconazole-Induced Alopecia in an Animal Model and Human Cohort.

Fluconazole-induced alopecia is a significant problem for patients receiving long-term therapy. We evaluated the hair cycle changes of fluconazole in a rat model and investigated potential molecular mechanisms. Plasma and tissue levels of retinoic acid were not found to be causal. Human patients with alopecia attributed to fluconazole also underwent detailed assessment and in both our murine model and human cohort fluconazole induced telogen effluvium. Future work further examining the mechanism of fluconazole-induced alopecia should be undertaken

Tips and tricks for robotic pancreatoduodenectomy with superior mesenteric/portal vein resection and reconstruction

Background Open pancreatoduodenectomy with vein resection (OPD-VR) is now standard of care in patients who responded to neoadjuvant therapies. Feasibility of robotic pancreatoduodenectomy (RPD) with vein resection (RPD-VR) was shown, but no study provided a detailed description of the technical challenges associated with this formidable operation. Herein, we describe the trips and tricks for technically successful RPD-VR.Methods The vascular techniques used in RPD-VR were borrowed from OPD-VR, as well as from our experience with robotic transplantation of both kidney and pancreas. Vein resection was classified into 4 types according to the international study group of pancreatic surgery. Each type of vein resection was described in detail and shown in a video.Results Between October 2008 and November 2021, a total of 783 pancreatoduodenectomies were performed, including 233 OPDs-VR (29.7%). RPD was performed in 256 patients (32.6%), and RPDs-VR in 36 patients (4.5% of all pancreatoduodenectomies; 15.4% of all pancreatoduodenectomies with vein resection; 14.0% of all RPDs). In RPD-VR vein resections were: 4 type 1 (11.1%), 10 type 2 (27.8%), 12 type 3 (33.3%) and 10 type 4 (27.8%). Vascular patches used in type 2 resections were made of peritoneum (n = 8), greater saphenous vein (n = 1), and deceased donor aorta (n = 1). Interposition grafts used in type 4 resections were internal left jugular vein (n = 8), venous graft from deceased donor (n = 1) and spiral saphenous vein graft (n = 1). There was one conversion to open surgery (2.8%). Ninety-day mortality was 8.3%. There was one (2.8%) partial vein thrombosis, treated with heparin infusion.Conclusions We have reported 36 technically successful RPDs-VR. We hope that the tips and tricks provided herein can contribute to safer implementation of RPD-VR. Based on our experience, and according to data from the literature, we strongly advise that RPD-VR is performed by expert surgeons at high volume centers

Characterization of Two Novel Variants of the Steroidogenic Acute Regulatory Protein Identified in a Girl with Classic Lipoid Congenital Adrenal Hyperplasia

Congenital adrenal hyperplasia (CAH) consists of several autosomal recessive disorders that inhibit steroid biosynthesis. We describe a case report diagnosed with adrenal insufficiency due to low adrenal steroids and adrenocorticotropic hormone excess due to lack of cortisol negative feedback signaling to the pituary gland. Genetic work up revealed two missense variants, p.Thr204Arg and p.Leu260Arg in the STAR gene, inherited by both parents (non-consanguineous). The StAR protein supports CYP11A1 enzyme to cleave the side chain of cholesterol and synthesize pregnenolone which is metabolized to all steroid hormones. We used bioinformatics to predict the impact of the variants on StAR activity and then we performed functional tests to characterize the two novel variants. In a cell system we tested the ability of variants to support cholesterol conversion to pregnenolone and measured their mRNA and protein expression. For both variants, we observed loss of StAR function, reduced protein expression and categorized them as pathogenic variants according to guidelines of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. These results fit the phenotype of the girl during diagnosis. This study characterizes two novel variants and expands the list of missense variants that cause CAH