492 research outputs found

    Interim Service ISDN Satellite (ISIS) network model for advanced satellite designs and experiments

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    The Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) Network Model for Advanced Satellite Designs and Experiments describes a model suitable for discrete event simulations. A top-down model design uses the Advanced Communications Technology Satellite (ACTS) as its basis. The ISDN modeling abstractions are added to permit the determination and performance for the NASA Satellite Communications Research (SCAR) Program

    Traffic model for advanced satellite designs and experiments for ISDN services

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    The data base structure and fields for categorizing and storing Integrated Services Digital Network (ISDN) user characteristics is outlined. This traffic model data base will be used to exercise models of the ISDN Advanced Communication Satellite to determine design parameters and performance for the NASA Satellite Communications Applications Research (SCAR) Program

    Critical Thinking in Teacher Education: A Process-Oriented Research Agenda

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    In recent years, critical thinking has become a central focus of education, especially in North America. Within this focus, there has been a major debate regarding the generalisability of specificity of critical thinking. The main issue in this connection appears to have been whether critical thinking needs to be closely linked with traditional disciplines. If critical thinking is really as vital as its proponents maintain, then it will also be important in applied fields such as teacher education. It is our intention in this paper to explore the implications, for teacher education, of taking critical thinking seriously

    CASE REPORT: Liver Failure in a 4-month-old male with SMA type 2 after gene therapy/Onasemnogene abeparvovec (Zolgensma)

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    Introduction: Spinal muscular atrophy (SMA) is characterized by muscle weakness and atrophy resulting from progressive degeneration of the anterior horn cells in the spinal cord and the brain stem nuclei. The onset of weakness ranges from before birth to adulthood. The weakness is symmetric, proximal \u3e distal, and progressive. Onasemnogene abeparvovec (ZOLGENSMA) is a viral vector-based gene therapy designed to deliver a functional copy of the human survival motor neuron (SMN) gene to the motor neuron cells of patients with spinal muscular atrophy (SMA). It was approved in May 2019 in the USA for the treatment of pediatric patients aged \u3c 2 years with SMA and bi-allelic mutations in the SMN1 gene. There has been significant motor function gain from the patients in and out of the clinical trials However, it can cause an immune response that could lead to an increase in enzymes produced by the liver. In one paper that studies over 100 SMA patients treated with Onasemnogene abeparvovec, 34% had a least one adverse event within the hepatotoxicity category. All adverse events associated with increased serum aminotransferases concentrations resolved completely with the majority receiving prednisolone from 60–120 days. Our case study discusses another SMA type 2 male, treated with Onasemnogene abeparvovec IV infusion therapy that presented 23 days later with liver failure. Objective: The purpose is to present an adverse reaction to the gene therapy/ZOLGENSMA given to a SMA 2 patient, there is not a lot of literature out there on adverse events to this drug that was recently approved in 2019 here is the case presentation: 4 month, 21 day old male with a past medical history of Spinal Muscular Atrophy (SMA) type two was administer an IV infusion of the gene therapy, Zolgensma. His diagnosis was achieved before he was symptomatic because of his older sisters diagnosis of SMA type II. After reviewing the diagnosis with mom and the benefits and risks to all of the three treatments that are approved by the FDA for SMA type 2 (onasemnogene, nusinersen, and risdiplam), the mother chose gene therapy, Zolgensma (onasemnogene). The patient was referred to occupational, physical, and speech therapy. He was also referred to a local pediatric cardiologist and a pediatric pulmonologist for disease related restrictive lung disease. Per the pulmonologist’s recommendations, he was doing cough assist about 3-5 times per day and was also started on Synagis intramuscular for RSV prevention because of his neuromuscular disease process and inability to clear secretions. Antibodies to the adeno-associated viral vector were measured in his serum before the treatment, his titer showed 1:25 which cleared him for treatment, anti-AAV9 antibody titer of Twenty two days after the infusion and following the prednisone taper, his labs showed elevated liver enzymes, troponin, and platelets.. His prednisone dose was increased to increase to 12 ml daily + Ranitidine and he was followed in the clinic a few days later. In the clinic, he is noted to have mild jaundice of the sclera and skin, and he was alert and active. As per mom, she noticed that he began having a yellow tint to the skin and of the eyes 26 days after the infusion. He had been eating well, however, she noticed that his stools are now more pale than previously. She also notes that he was sleeping more and has decreased activity levels. Stat labs were ordered to assess liver function including: ammonia, PT/PTT, INR, total/direct bilirubin, albumin, troponin, CMP, and CBC. He was found to have decreased liver function and admitted to the ICU. (PATIENT IS STILL IN THE ICU- NEED TO UPDATE LAB VALUES next week) Methods: This is a case report so I will just be explaining the history and physical findings and lab results Results: This is a case study on an adverse event to the gene therapy Zolgensma. My methods will include lab values, and the history and physical findings, MOA of the gene therapy, treatment of the liver failure that resulted from the gene therapy. (PATIENT IS STILL IN THE ICU- NEED TO UPDATE LAB VALUES next week) Discussion: Due to how rare SMA is and the novel new treatment of onasemnogene abeparvovec, a treatment protocol for the adverse reaction of liver failure has not been standardized. Conclusions: Next steps include reporting the adverse effects of this treatment, continue gathering data on treated patients, and developing a standardized treatment for patients who develop severe liver failure to onasemnogene abeparvovec gene therapy

    Unified signature cumulants and generalized Magnus expansions

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    The signature of a path can be described as its full non-commutative exponential. Following T. Lyons we regard its expectation, the expected signature, as path space analogue of the classical moment generating function. The logarithm thereof, taken in the tensor algebra, defines the signature cumulant. We establish a universal functional relation in a general semimartingale context. Our work exhibits the importance of Magnus expansions in the algorithmic problem of computing expected signature cumulants, and further offers a far-reaching generalization of recent results on characteristic exponents dubbed diamond and cumulant expansions; with motivation ranging from financial mathematics to statistical physics. From an affine process perspective, the functional relation may be interpreted as infinite-dimensional, non-commutative (``Hausdorff") variation of Riccati's equation. Many examples are given

    The Association Value of Thirty Meaningful Words

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    Forty-one men and women undergraduates individually wrote down the verbal associations arising in relation to each of 30 three-letter meaningful words, with a time allowance of 1 min. per word. The association value of each word was defined as the mean number of acceptable words written in response to it. Two sets of words were then chosen from the list for subsequent use as response terms in a verbal-motor transfer experiment. One set, formally similar, was found to have a mean association value of 8.752. The other set, formally distinct, had a satisfactorily comparable mean association value of 8.792

    Mean-Field Liquidation Games with Market Drop-out

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    We consider a novel class of portfolio liquidation games with market drop-out ("absorption"). More precisely, we consider mean-field and finite player liquidation games where a player drops out of the market when her position hits zero. In particular round-trips are not admissible. This can be viewed as a no statistical arbitrage condition. In a model with only sellers we prove that the absorption condition is equivalent to a short selling constraint. We prove that equilibria (both in the mean-field and the finite player game) are given as solutions to a non-linear higher-order integral equation with endogenous terminal condition. We prove the existence of a unique solution to the integral equation from which we obtain the existence of a unique equilibrium in the MFG and the existence of a unique equilibrium in the NN-player game. We establish the convergence of the equilibria in the finite player games to the obtained mean-field equilibrium and illustrate the impact of the drop-out constraint on equilibrium trading rates

    The Effects of Fault Roughness on the Earthquake Nucleation Process

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    We study numerically the effects of fault roughness on the nucleation process during earthquake sequences. The faults are governed by a rate and state friction law. The roughness introduces local barriers that complicate the nucleation process and result in asymmetric expansion of the rupture, nonmonotonic increase in the slip rates on the fault, and the generation of multiple slip pulses. These complexities are reflected as irregular fluctuations in the moment rate. There is a large difference between first slip events in the sequences and later events. In the first events, for roughness amplitude b_r ≤ 0.002, there is a large increase in the nucleation length with increasing br. For larger values of b_r, slip is mostly aseismic. For the later events there is a trade-off between the effects of the finite fault length and the fault roughness. For b_r ≤ 0.002, the finite length is a more dominant factor and the nucleation length barely changes with br. For larger values of b_r, the roughness plays a larger role and the nucleation length increases significantly with b_r. Using an energy balance approach, where the roughness is accounted for in the fault stiffness, we derive an approximate solution for the nucleation length on rough faults. The solution agrees well with the main trends observed in the simulations for the later events and provides an estimate of the frictional and roughness properties under which faults experience a transition between seismic and aseismic slip

    Evaluating macropore flow with temporal electrical resistivity imaging in riparian areas

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    Riparian soils are uniquely susceptible to the formation of macropores, voids with preferential flow in comparison to surrounding strata, which are hypothesized to promote fast transport of water through soil layers. Electrical Resistivity Imaging (ERI) can locate spatial heterogeneities in soil wetting patterns caused by preferential flow through macropores, thus optimizing the design of riparian buffers. Temporal ERI (TERI) imaging was conducted in a fine and coarse field setting with artificial macropores to evaluate flow under unsaturated simulated rainfall conditions and saturated infiltrometer conditions.Results from field data show that while macropores are detectable using TERI datasets, this results in an average field setting would detect the wetted zone in the vicinity of a macropore, not the macropore itself. The results were similar for both the primary fine grain soil site in Oklahoma as well as the coarse grain site in North Carolina. TERI data indicate that without artificial rainfall or macropores in low noise conditions, a single macropore would not be detected, a wetted zone would be the best detection. In a field evaluation of naturally occurring macropores, the TERI technique would detect the wetted zone around a macropore similar to an area of increased hydraulic conductivity in a heterogeneous soil matrix. The findings from the first set of experimentation indicate an appropriate resolution and electrode spacing for the second experiment in this thesis. The second experiment entails the tracer velocity mapping of alluvial soil. Preliminary results show TERI as a viable method for calculating the fluid velocity along a series of vertical profiles in the coarse-grained North Carolina field site

    Optimal stopping with signatures

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    We propose a new method for solving optimal stopping problems (such as American option pricing in finance) under minimal assumptions on the underlying stochastic process. We consider classic and randomized stopping times represented by linear functionals of the associated rough path signature, and prove that maximizing over the class of signature stopping times, in fact, solves the original optimal stopping problem. Using the algebraic properties of the signature, we can then recast the problem as a (deterministic) optimization problem depending only on the (truncated) expected signature. The only assumption on the process is that it is a continuous (geometric) random rough path. Hence, the theory encompasses processes such as fractional Brownian motion which fail to be either semi-martingales or Markov processes
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