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  1. Article: An information-theoretic approach to study spatial dependencies in small datasets.

    Porfiri, Maurizio / Ruiz Marín, Manuel

    Proceedings. Mathematical, physical, and engineering sciences

    2020  Volume 476, Issue 2242, Page(s) 20200113

    Abstract: From epidemiology to economics, there is a fundamental need of statistically principled approaches to unveil spatial patterns and identify their underpinning mechanisms. Grounded in network and information theory, we establish a non-parametric scheme to ... ...

    Abstract From epidemiology to economics, there is a fundamental need of statistically principled approaches to unveil spatial patterns and identify their underpinning mechanisms. Grounded in network and information theory, we establish a non-parametric scheme to study spatial associations from limited measurements of a spatial process. Through the lens of network theory, we relate spatial patterning in the dataset to the topology of a network on which the process unfolds. From the available observations of the spatial process and a candidate network topology, we compute a mutual information statistic that measures the extent to which the measurement at a node is explained by observations at neighbouring nodes. For a class of networks and linear autoregressive processes, we establish closed-form expressions for the mutual information statistic in terms of network topological features. We demonstrate the feasibility of the approach on synthetic datasets comprising 25-100 measurements, generated by linear or nonlinear autoregressive processes. Upon validation on synthetic processes, we examine datasets of human migration under climate change in Bangladesh and motor vehicle deaths in the United States of America. For both these real datasets, our approach is successful in identifying meaningful spatial patterns, begetting statistically-principled insight into the mechanisms of important socioeconomic problems.
    Language English
    Publishing date 2020-10-21
    Publishing country England
    Document type Journal Article
    ZDB-ID 209241-4
    ISSN 1471-2946 ; 1364-5021 ; 0962-8444 ; 0080-4630 ; 0950-1207
    ISSN (online) 1471-2946
    ISSN 1364-5021 ; 0962-8444 ; 0080-4630 ; 0950-1207
    DOI 10.1098/rspa.2020.0113
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Transfer entropy on symbolic recurrences.

    Porfiri, Maurizio / Ruiz Marín, Manuel

    Chaos (Woodbury, N.Y.)

    2019  Volume 29, Issue 6, Page(s) 63123

    Abstract: Recurrence quantification analysis offers a powerful framework to investigate complexity in dynamical systems. While several studies have demonstrated the possibility of multivariate recurrence quantification analysis, information-theoretic tools for the ...

    Abstract Recurrence quantification analysis offers a powerful framework to investigate complexity in dynamical systems. While several studies have demonstrated the possibility of multivariate recurrence quantification analysis, information-theoretic tools for the discovery of causal links remain elusive. Particularly enticing is to formulate information-theoretic tools on symbolic recurrence plots, which alleviate some of the methodological challenges of traditional recurrence plots and offer a richer representation of recurrences. Toward this aim, we establish a probability space in which we ground a theory of information that encodes information in the recurrences of the symbols. We introduce transfer entropy on symbolic recurrences as a tool to guide the inference of the strength and direction of the interaction between dynamical systems. We demonstrate statistically reliable discovery of causal links on synthetic and experimental time series, from only two time series or a larger dataset with multiple realizations. The proposed approach brings together recurrence plots, information theory, and symbolic dynamics to empower researchers and practitioners with effective means to visualize and quantify interactions in dynamical systems.
    Language English
    Publishing date 2019-07-01
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1472677-4
    ISSN 1089-7682 ; 1054-1500
    ISSN (online) 1089-7682
    ISSN 1054-1500
    DOI 10.1063/1.5094900
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: Quantifying the role of the COVID-19 pandemic in the 2020 U.S. presidential elections.

    De Lellis, Pietro / Ruiz Marín, Manuel / Porfiri, Maurizio

    The European physical journal. Special topics

    2021  Volume 231, Issue 9, Page(s) 1635–1643

    Abstract: In the media, a prevalent narrative is that the incumbent United States President Donald J. Trump lost the 2020 elections because of the way he handled the COVID-19 pandemic. Quantitative evidence to support this narrative is, however, limited. We put ... ...

    Abstract In the media, a prevalent narrative is that the incumbent United States President Donald J. Trump lost the 2020 elections because of the way he handled the COVID-19 pandemic. Quantitative evidence to support this narrative is, however, limited. We put forward a spatial, information-theoretic approach to critically examine the link between voting behavior and COVID-19 incidence in the 2020 presidential elections. The approach overcomes classical limitations of traditional regression analysis, where it does not require an underlying mathematical model and it can capture nonlinear interactions. From the analysis of county-level data, we uncovered a robust association between voting behavior and prevalence of COVID-19 cases. Surprisingly, such an association points in the opposite direction from the accepted narrative: in counties that experienced less COVID-19 cases, the incumbent President lost more ground to his opponent, now President Joseph R. Biden Jr. A tenable explanation of this observation is the different attitude of liberal and conservative voters toward the pandemic, which led to more COVID-19 spreading in counties with a larger share of republican voters.
    Language English
    Publishing date 2021-10-28
    Publishing country France
    Document type Journal Article
    ZDB-ID 2267176-6
    ISSN 1951-6401 ; 1951-6355
    ISSN (online) 1951-6401
    ISSN 1951-6355
    DOI 10.1140/epjs/s11734-021-00299-3
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Inference of time-varying networks through transfer entropy, the case of a Boolean network model.

    Porfiri, Maurizio / Ruiz Marín, Manuel

    Chaos (Woodbury, N.Y.)

    2018  Volume 28, Issue 10, Page(s) 103123

    Abstract: Inferring network topologies from the time series of individual units is of paramount importance in the study of biological and social networks. Despite considerable progress, our success in network inference is largely limited to static networks and ... ...

    Abstract Inferring network topologies from the time series of individual units is of paramount importance in the study of biological and social networks. Despite considerable progress, our success in network inference is largely limited to static networks and autonomous node dynamics, which are often inadequate to describe complex systems. Here, we explore the possibility of reconstructing time-varying weighted topologies through the information-theoretic notion of transfer entropy. We focus on a Boolean network model in which the weight of the links and the spontaneous activity periodically vary in time. For slowly-varying dynamics, we establish closed-form expressions for the stationary periodic distribution and transfer entropy between each pair of nodes. Our results indicate that the instantaneous weight of each link is mapped into a corresponding transfer entropy value, thereby affording the possibility of pinpointing the dominant weights at each time. However, comparing transfer entropy readings at different times may provide erroneous estimates of the strength of the links in time, due to a counterintuitive modulation of the information flow by the non-autonomous dynamics. In fact, this time variation should be used to scale transfer entropy values toward the correct inference of the time evolution of the network weights. This study constitutes a necessary step toward a mathematically-principled use of transfer entropy to reconstruct time-varying networks.
    Language English
    Publishing date 2018-10-31
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1472677-4
    ISSN 1089-7682 ; 1054-1500
    ISSN (online) 1089-7682
    ISSN 1054-1500
    DOI 10.1063/1.5047429
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Symbolic dynamics of animal interaction.

    Porfiri, Maurizio / Ruiz Marín, Manuel

    Journal of theoretical biology

    2017  Volume 435, Page(s) 145–156

    Abstract: Since its introduction nearly two decades ago, transfer entropy has contributed to an improved understanding of cause-and-effect relationships in coupled dynamical systems from raw time series. In the context of animal behavior, transfer entropy might ... ...

    Abstract Since its introduction nearly two decades ago, transfer entropy has contributed to an improved understanding of cause-and-effect relationships in coupled dynamical systems from raw time series. In the context of animal behavior, transfer entropy might help explain the determinants of leadership in social groups and elucidate escape response to predator attacks. Despite its promise, the potential of transfer entropy in animal behavior is yet to be fully tested, and a number of technical challenges in information theory and statistics remain open. Here, we examine an alternative approach to the computation of transfer entropy based on symbolic dynamics. In this context, a symbol is associated with a specific locomotory bout across two or more consecutive time instants, such as reversing the swimming direction. Symbols encapsulate salient locomotory patterns and the associated permutation transfer entropy quantifies the ability to predict the patterns of an individual given those of another individual. We demonstrate this framework on an existing dataset on fish, for which we have knowledge of the underlying cause-and-effect relationship between the focal subject and the stimulus. Symbolic dynamics offers an intuitive and robust approach to study animal behavior, which could enable the inference of causal relationship from noisy experimental observations of limited duration.
    MeSH term(s) Animals ; Behavior, Animal ; Entropy ; Fishes ; Information Theory ; Leadership ; Nonlinear Dynamics ; Swimming
    Language English
    Publishing date 2017-09-13
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2972-5
    ISSN 1095-8541 ; 0022-5193
    ISSN (online) 1095-8541
    ISSN 0022-5193
    DOI 10.1016/j.jtbi.2017.09.005
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Del check list a la cirugía segura.

    Soria Aledo, Víctor / Ruiz Marín, Miguel

    Journal of healthcare quality research

    2019  Volume 34, Issue 6, Page(s) 281–282

    Title translation From the check list to safe surgery.
    MeSH term(s) Checklist ; Communication ; Emergencies ; Humans ; Intraoperative Complications/prevention & control ; Medical Errors/prevention & control ; Patient Care Team ; Patient Safety ; Postoperative Complications/prevention & control
    Language Spanish
    Publishing date 2019-11-17
    Publishing country Spain
    Document type Editorial
    ISSN 2603-6479
    ISSN (online) 2603-6479
    DOI 10.1016/j.jhqr.2019.10.001
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Assessment of postoperative morbidity in Spanish hospitals: Results from a national survey.

    de la Plaza Llamas, Roberto / Parés, David / Soria Aledó, Víctor / Cabezali Sánchez, Roger / Ruiz Marín, Miguel / Senent Boza, Ana / Romero Simó, Manuel / Alonso Hernández, Natalia / Vallverdú-Cartié, Helena / Mayol Martínez, Julio

    Cirugia espanola

    2024  

    Abstract: Background: The methodology used for recording, evaluating and reporting postoperative complications (PC) is unknown. The aim of the present study was to determine how PC are recorded, evaluated, and reported in General and Digestive Surgery Services ( ... ...

    Abstract Background: The methodology used for recording, evaluating and reporting postoperative complications (PC) is unknown. The aim of the present study was to determine how PC are recorded, evaluated, and reported in General and Digestive Surgery Services (GDSS) in Spain, and to assess their stance on morbidity audits.
    Methods: Using a cross-sectional study design, an anonymous survey of 50 questions was sent to all the heads of GDSS at hospitals in Spain.
    Results: The survey was answered by 67 out of 222 services (30.2%). These services have a reference population (RP) of 15 715 174 inhabitants, representing 33% of the Spanish population. Only 15 services reported being requested to supply data on morbidity by their hospital administrators. Eighteen GDSS, with a RP of 3 241 000 (20.6%) did not record PC. Among these, 7 were accredited for some area of training. Thirty-six GDSS (RP 8 753 174 (55.7%) did not provide details on all PC in patients' discharge reports. Twenty-four (37%) of the 65 GDSS that had started using a new surgical procedure/technique had not recorded PC in any way. Sixty-five GDSS were not concerned by the prospect of their results being audited, and 65 thought that a more comprehensive knowledge of PC would help them improve their results. Out of the 37 GDSS that reported publishing their results, 27 had consulted only one source of information: medical progress records in 11 cases, and discharge reports in 9.
    Conclusions: This study reflects serious deficiencies in the recording, evaluation and reporting of PC by GDSS in Spain.
    Language English
    Publishing date 2024-04-12
    Publishing country Spain
    Document type Journal Article
    ISSN 2173-5077
    ISSN (online) 2173-5077
    DOI 10.1016/j.cireng.2024.03.008
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article: Lumen-apposing metal stent deployment failure.

    López Morales, Pedro / Ruiz Marín, Miguel / Albarracín Marín-Blázquez, Antonio

    Revista espanola de enfermedades digestivas : organo oficial de la Sociedad Espanola de Patologia Digestiva

    2020  Volume 113, Issue 3, Page(s) 224–225

    Abstract: Endoscopic ultrasound-guided transmural drainage has become a first-line therapy for pancreatic fluid collections (1). The appearance of lumen-apposing metal stents has resulted in an authentic revolution, due to their efficacy (clinical success rate of ... ...

    Abstract Endoscopic ultrasound-guided transmural drainage has become a first-line therapy for pancreatic fluid collections (1). The appearance of lumen-apposing metal stents has resulted in an authentic revolution, due to their efficacy (clinical success rate of 93%) and easy deployment (technical success rate of 98%) (2). They are associated with a shorter procedure time, lower risk of migration and a wider lumen, which could provide a more effective drainage (3). We report the case of a 78-year-old male who developed an infected pancreatic pseudocyst as a late complication of an acalculous severe acute pancreatitis. An endoscopic ultrasound-guided transmural drainage was performed after a failed computed tomography-guided percutaneous drainage with placement of a pig-tail catheter. A gastrocystic fistula was created and an AxiosTM lumen-apposing metal stent (Boston Scientific; Massachusetts, United States) was inserted. Nevertheless, it remained lodged in the pancreatic pseudocyst at the time of deployment. A computed tomography scan confirmed stent placement inside the collection (Figure 1). After endoscopic balloon dilatation of gastrocystic fistulous tract, removal was unsuccessful with proximal traction of the lumen stent flange using biopsy forceps. Surgical treatment was decided and a gastrotomy was performed, the fistula was identified in the posterior gastric wall and the stent was removed. Endoscopic ultrasound-guided transmural drainage of pancreatic fluid collections using lumen-apposing metal stents is a safe procedure. However, it is not exempt of complications such as stent migration, bleeding, gastrointestinal perforation and air embolism (4). Technical failure of lumen-apposing metal stents deployment is a rare complication that may require surgical treatment if endoscopic removal is not possible.
    MeSH term(s) Acute Disease ; Aged ; Drainage ; Endosonography ; Humans ; Male ; Pancreatic Pseudocyst ; Pancreatitis/diagnostic imaging ; Pancreatitis/etiology ; Stents ; Treatment Outcome
    Language English
    Publishing date 2020-11-19
    Publishing country Spain
    Document type Case Reports ; Journal Article
    ZDB-ID 1070381-0
    ISSN 1130-0108 ; 0212-7512
    ISSN 1130-0108 ; 0212-7512
    DOI 10.17235/reed.2020.7060/2020
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Giant Diverticulum of the Sigmoid Colon.

    González-Valverde, Francisco Miguel / Madrid-Baños, Beatriz / Ruiz-Marín, Miguel

    Journal of gastrointestinal surgery : official journal of the Society for Surgery of the Alimentary Tract

    2020  Volume 25, Issue 5, Page(s) 1347–1349

    MeSH term(s) Colon, Sigmoid/diagnostic imaging ; Colon, Sigmoid/surgery ; Diverticulum/diagnostic imaging ; Diverticulum/surgery ; Diverticulum, Colon/diagnostic imaging ; Diverticulum, Colon/surgery ; Humans ; Sigmoid Diseases/diagnostic imaging ; Sigmoid Diseases/surgery
    Language English
    Publishing date 2020-10-29
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2012365-6
    ISSN 1873-4626 ; 1934-3213 ; 1091-255X
    ISSN (online) 1873-4626 ; 1934-3213
    ISSN 1091-255X
    DOI 10.1007/s11605-020-04841-x
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  10. Article ; Online: De la cabina al quirófano.

    Fernández-Salmerón, P / Ruiz-Marín, M / Soria-Aledo, V

    Revista de calidad asistencial : organo de la Sociedad Espanola de Calidad Asistencial

    2016  Volume 31, Issue 6, Page(s) 319–321

    Title translation From the cockpit to the operating room.
    Language Spanish
    Publishing date 2016-11
    Publishing country Spain
    Document type Editorial
    ISSN 1887-1364
    ISSN (online) 1887-1364
    DOI 10.1016/j.cali.2016.07.001
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