2,145 research outputs found

    Deterministic Multi-sensor Measurement-adaptive Birth using Labeled Random Finite Sets

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    Measurement-adaptive track initiation remains a critical design requirement of many practical multi-target tracking systems. For labeled random finite sets multi-object filters, prior work has been established to construct a labeled multi-object birth density using measurements from multiple sensors. A truncation procedure has also been provided that leverages a stochastic Gibbs sampler to truncate the birth density for scalability. In this work, we introduce a deterministic herded Gibbs sampling truncation solution for efficient multi-sensor adaptive track initialization. Removing the stochastic behavior of the track initialization procedure without impacting average tracking performance enables a more robust tracking solution more suitable for safety-critical applications. Simulation results for linear sensing scenarios are provided to verify performance.Comment: Accepted to the 2023 Proc. IEEE 26th Int. Conf. Inf. Fusio

    On Gibbs Sampling Architecture for Labeled Random Finite Sets Multi-Object Tracking

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    Gibbs sampling is one of the most popular Markov chain Monte Carlo algorithms because of its simplicity, scalability, and wide applicability within many fields of statistics, science, and engineering. In the labeled random finite sets literature, Gibbs sampling procedures have recently been applied to efficiently truncate the single-sensor and multi-sensor δ\delta-generalized labeled multi-Bernoulli posterior density as well as the multi-sensor adaptive labeled multi-Bernoulli birth distribution. However, only a limited discussion has been provided regarding key Gibbs sampler architecture details including the Markov chain Monte Carlo sample generation technique and early termination criteria. This paper begins with a brief background on Markov chain Monte Carlo methods and a review of the Gibbs sampler implementations proposed for labeled random finite sets filters. Next, we propose a short chain, multi-simulation sample generation technique that is well suited for these applications and enables a parallel processing implementation. Additionally, we present two heuristic early termination criteria that achieve similar sampling performance with substantially fewer Markov chain observations. Finally, the benefits of the proposed Gibbs samplers are demonstrated via two Monte Carlo simulations.Comment: Accepted to the 2023 Proc. IEEE 26th Int. Conf. Inf. Fusio

    Kinetics of Oxygen Transport in Monomeric Sarcosine Oxidase

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    Flavin-containing oxidases are a class of proteins which use oxygen to regenerate the oxidized state of the isoalloxazine ring in flavin adenine dinucleotide (FAD) or flavin mononucleotide (FMN) after it has been reduced by substrate oxidation. Though well characterized experimentally, many questions linger regarding how small molecules access the active site as well as where oxygen activation occurs in flavin-containing oxidases. A prototypical member of this family is monomeric sarcosine oxidase (MSOX), and it is perhaps the most well studied. Despite knowing which features are essential for catalysis as well as the location of the substrate binding site, it is unclear how oxygen accesses the site since the only clear entryway can be partially blocked by the larger substrate sarcosine. As such, two competing mechanisms have gained attention centering around the order by which ligands enter the binding site. In this thesis, we detail the use of all atom molecular dynamics (MD) studies to identify how oxygen accesses the MSOX active site, as well as characterize the resulting kinetic network. We use the single sweep method to identify four potential routes for oxygen to travel from the surface of MSOX to the active site. Then, using Markovian milestoning with Voronoi tessellations (MMVT), we refine the pathways identified in single sweep and develop a Markov state model describing the kinetics of oxygen entry and exit. We calculate entry and exit mean first passage times (MFPT) for oxygen from this model, which are used to compute second order rate constants for entry and first order rate constants for exit. Our calculated rate constants and mechanisms show that the presence of a substrate-mimicking inhibitor markedly influences the kinetics of oxygen entry and exit. The bound competitive inhibitor changes the protein structure sufficiently to shut down almost all major oxygen channels save one, which it opens, speeding entry but greatly slowing down oxygen exit, relative to the substrate-free enzyme. This means that our kinetic analysis predicts oxygen exhibits a longer residence time within MSOX when a substrate-like ligand is present. This supports the so-called "modified ping-pong" mechanism, in agreement with previous experimental results, thus lending validity to our approach. Furthermore, our computed second-order entry rate constants are larger by about an order of magnitude than are experimentally determined oxygen consumption rate constants. Since oxygen consumption combines the processes of entry and electron transfer, we conclude that of these two, entry is not rate-limiting in the overall catalytic cycle, regardless of whether or not a substrate-like ligand is bound. Finally, because this work represents the first test of the MMVT approach for comparing kinetics of ligand entry for an enzyme in two distinct states, we not surprisingly uncovered inefficiencies in the approach. We tested one idea for gaining efficiency based on the "finite-temperature" string method, in which transport channels can be determined and kinetically characterized on-the-fly, rather than sequentially. Our results indicate that more research in that area is needed.Ph.D., Chemical Engineering -- Drexel University, 201

    Meeting the ISTE Challenge in the Field: An Overview of the First Six Distinguished Achievement Award Winning Programs

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    The 2002 National Educational Technology Standards (NETS) Distinguished Achievement Awards, sponsored by the International Society for Technology in Education (ISTE), were awarded to six teacher education programs across the United States. The awards recognize institutions that exemplify successful integration of the National Educational Technology Standards for Teachers (NETS[solid dot]T) into teacher education programs. Institutions across the country completed an extensive application process to be selected one of the first six recipients of the ISTE Distinguished Achievement award. This process included online documentation that demonstrated the program\u27s implementation of the NETS[solid dot]T models and practices. This article provides a means of uniting various programs and program developers (teacher educators and instructional technologists) by looking at the most common obstacles they face in the pursuit of appropriate infusion of technology into teacher education programs and workable solutions for overcoming those obstacles

    Association of antiseizure medications and adverse cardiovascular events: A global health federated network analysis

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    AbstractObjectiveA diagnosis of epilepsy has been associated with adverse cardiovascular events (CEs), but the extent to which antiseizure medications (ASMs) may contribute to this is not well understood. The aim of this study was to compare the risk of adverse CEs associated with ASM in patients with epilepsy (PWE).MethodsA retrospective case–control cohort study was conducted using TriNetX, a global health federated network of anonymized patient records. Patients older than 18 years, with a diagnosis of epilepsy (International Classification of Diseases, 10th Revision code G40) and a medication code of carbamazepine, lamotrigine, or valproate were compared. Patients with cardiovascular disease prior to the diagnosis of epilepsy were excluded. Cohorts were 1:1 propensity score matched (PSM) according to age, sex, ethnicity, hypertension, heart failure, atherosclerotic heart disease, atrial and cardiac arrythmias, diabetes, disorders of lipoprotein metabolism, obesity, schizophrenia and bipolar disorder, medications, and epilepsy classification. The primary outcome was a composite of adverse CEs (ischemic stroke, acute ischemic heart disease, and heart failure) at 10 years. Cox regression analyses were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) following 1:1 PSM.ResultsOf 374 950 PWE included; three cohorts were established after PSM: (1) carbamazepine compared to lamotrigine, n = 4722, mean age 37.4 years; (2) valproate compared to lamotrigine, n = 5478, mean age 33.9 years; and (3) valproate compared to carbamazepine, n = 4544, mean age 37.0 years. Carbamazepine and valproate use were associated with significantly higher risk of composite cardiovascular outcome compared to lamotrigine (HR = 1.390, 95% CI = 1.160–1.665 and HR = 1.264, 95% CI = 1.050–1.521, respectively). Valproate was associated with a 10‐year higher risk of all‐cause death than carbamazepine (HR = 1.226, 95% CI = 1.017–1.478), but risk of other events was not significantly different.SignificanceCarbamazepine and valproate were associated with increased CE risks compared to lamotrigine. Cardiovascular risk factor monitoring and careful follow‐up should be considered for these patients.</jats:sec

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London
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