64 research outputs found

    On the Robust Control of Continuous-time Markov Jump Linear Systems Subject to Block-diagonal Uncertainty

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    Abstract-This paper addresses the robust H 2 2 2 and H ∞ ∞ ∞ control problems for continuous-time Markov jump linear systems subjected to block-diagonal perturbations. The proposed approach features the introduction of more powerful scaling techniques than the ones available in the current Markov jump linear systems literature. We further propose uncertaintydependent LMI design methods to treat the case of polytopic uncertainty on the transition rates of the Markov process. In the end of the paper, an application of the main results is illustrated with a numerical example

    Nuclear DNA Replication in Trypanosomatids:There Are No Easy Methods for Solving Difficult Problems

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    In trypanosomatids, etiological agents of devastating diseases, replication is robust and finely controlled to maintain genome stability and function in stressful environments. However, these parasites encode several replication protein components and complexes that show potentially variant composition compared with model eukaryotes. This review focuses on the advances made in recent years regarding the differences and peculiarities of the replication machinery in trypanosomatids, including how such divergence might affect DNA replication dynamics and the replication stress response. Comparing the DNA replication machinery and processes of parasites and their hosts may provide a foundation for the identification of targets that can be used in the development of chemotherapies to assist in the eradication of diseases caused by these pathogens

    Guidelines for the management of neuroendocrine tumours by the Brazilian gastrointestinal tumour group

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    Neuroendocrine tumours are a heterogeneous group of diseases with a significant variety of diagnostic tests and treatment modalities. Guidelines were developed by North American and European groups to recommend their best management. However, local particularities and relativisms found worldwide led us to create Brazilian guidelines. Our consensus considered the best feasible strategies in an environment involving more limited resources. We believe that our recommendations may be extended to other countries with similar economic standards.Univ Sao Paulo, Inst Canc Estado Sao Paulo, BR-01246000 Sao Paulo, BrazilUniv Sao Paulo, Fac Med, Dept Radiol & Oncol, BR-01246903 Sao Paulo, BrazilHosp Sirio Libanes, BR-01308050 Sao Paulo, BrazilHosp Moinhos de Vento Porto Alegre, BR-90035000 Porto Alegre, RS, BrazilOncoctr, BR-30360680 Belo Horizonte, MG, BrazilUniv Fed Rio Grande do Sul, Dept Cirurgia, BR-90040060 Porto Alegre, RS, BrazilHosp Clin Porto Alegre, BR-90035903 Porto Alegre, RS, BrazilUniv Fed Ceara, Fac Med, Dept Fisiol & Farmacol, BR-60020180 Fortaleza, Ceara, BrazilHosp Univ Walter Cantidio, BR-60430370 Fortaleza, Ceara, BrazilInst Nacl Canc, BR-20230240 Rio De Janeiro, BrazilUniv Sao Paulo, Fac Med, Disciplina Endocrinol & Metabol, BR-01246903 Sao Paulo, BrazilAC Camargo Canc Ctr, Dept Surg, BR-01509010 Sao Paulo, BrazilUniv Sao Paulo, Fac Med, Dept Gastroenterol, Sao Paulo, BrazilUniv Fed Ciencias Saude Porto Alegre, BR-90050170 Porto Alegre, RS, BrazilHosp Albert Einstein, BR-05652900 Sao Paulo, BrazilHosp Base, Fac Med Sao Jose do Rio Preto, BR-15090000 Sao Paulo, BrazilSanta Casa Sao Jose do Rio Preto, BR-15025500 Sao Jose Do Rio Preto, BrazilPontificia Univ Catolica Parana, Hosp Erasto Gaertner, BR-81520060 Curitiba, Parana, BrazilUniv Fed Rio Grande do Norte, BR-59300000 Natal, RN, BrazilUniv Sao Paulo, Inst Coracao, BR-05403900 Sao Paulo, BrazilAC Camargo Canc Ctr, Med Oncol, BR-01509010 Sao Paulo, BrazilUniv Fed Sao Paulo, Disciplina Gastroenterol, BR-04021001 Sao Paulo, BrazilHosp Sao Rafael, BR-41253190 Salvador, BA, BrazilHosp Canc Barretos, Dept Cirurgia Aparelho Digest Alto & Hepatobiliop, BR-14784400 Sao Paulo, BrazilUniv Sao Paulo, Fac Med, Dept Patol, BR-01246903 Sao Paulo, BrazilClin AMO, BR-1950640 Salvador, BA, BrazilHosp Sao Jose, BR-01323001 Sao Paulo, BrazilUniv Nove de Julho, BR-02111030 Sao Paulo, BrazilUniv Fed Sao Paulo, Disciplina Gastroenterol, BR-04021001 Sao Paulo, BrazilWeb of Scienc

    The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2

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    Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age  6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score  652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701

    Discounted Markov decision processes via time aggregation

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    This paper applies two-phase time aggregation to solve discounted Markov decision processes (MDP). This procedure, recently proposed for average cost MDPs, is extended here discounted MDPs with a view at easing the computational burden associated to finding a quality solution within a reasonable time frame. Numerical examples are presented to illustrate the results.</p

    A two-phase time aggregation algorithm for average cost Markov decision processes

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    This paper introduces a two-phase approach to solve average cost Markov decision processes, which is based on state space embedding or time aggregation. In the first phase, time aggregation is applied for policy evaluation in a prescribed subset of the state space, and a novel result is applied to expand the evaluation to the whole state space. This evaluation is then used in the second phase in a policy improvement step, and the two phases are then sequentially applied until convergence is attained or a prescribed running time is exceeded.</p

    Standard dynamic programming applied to time aggregated Markov decision processes

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    In this note we address the time aggregation approach to ergodic finite state Markov decision processes with uncontrollable states. We propose the use of the time aggregation approach as an intermediate step toward constructing a transformed MDP whose state space is comprised solely of the controllable states. The proposed approach simplifies the iterative search for the optimal solution by eliminating the need to define an equivalent parametric function, and results in a problem that can be solved by simpler, standard MDP algorithms.</p
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