Optimal reinsurance of dependent risks

We analyse the problem of nding the optimal combination of quota-share and stop loss treaties, maximizing the expected utility or the adjustment coecient of the ce- dent, for each of two risks dependent through a copula structure. By risk we mean a line of business or a portfolio of policies. Results are obtained numerically, using the software Mathematica. Sensitivity of the optimal reinsurance strategy to several factors are investigated, including: i) the dependence level, by means of the Kendall's tau and the dependence parameter; ii) the type of dependence, using dierent copulas describing dierent tail behaviour; iii) the reinsurance calculation principles, where expected value, variance and standard deviation principles are considered. Results show that dierent dependence structures, yield signicantly dierent optimal solu- tions. The optimal treaty is also very sensible to the reinsurance premium calculation principle. Namely, for variance related premiums the optimal solution is not the pure stop loss. In general, the maximum adjustment coecient decreases when dependence increases..info:eu-repo/semantics/publishedVersio

COPD control: Can a consensus be found?

AbstractThere are currently no reliable instruments for assessing the onset and progression of chronic obstructive pulmonary disease (COPD) or predicting its prognosis. Currently, a comprehensive assessment of COPD including several objective and subjective parameters is recommended. However, the lack of biomarkers precludes a correct assessment of COPD severity, which consequently hampers adequate therapeutic approaches and COPD control. In the absence of a definition of “well-controlled disease”, a consensus regarding COPD control will be difficult to reach. However, COPD patient assessment should be multidimensional, and anchored in five points: control of symptoms, decline of pulmonary function, levels of physical activity, exacerbations, and Quality of Life.Several non-pharmacological and pharmacological measures are currently available to achieve disease control. Smoking cessation, vaccination, exercise training programs and pulmonary rehabilitation are recognized as important non-pharmacological measures but bronchodilators are the pivotal therapy in the control of COPD. This paper discusses several objective and subjective parameters that may bridge the gap between disease assessment and disease control. The authors conclude that, at present, it is not possible to reach a consensus regarding COPD control, essentially due to the lack of objective instruments to measure it. Some recommendations are set forth, but true COPD control awaits further objective assessments

Árgon-plasma no tratamento de leiomioma benigno metastizante pulmonar: um caso clínico

AbstractBenign metastasizing leiomyomas of the lung are rare smooth muscle cells tumours. We report the case of a 48 year-old female who was evaluated due to persistent cough, progressive dyspnoea and constitutional symptoms. Chest computed tomography revealed a left endobronchial mass, multiple parenchyma nodules and a pleural effusion. Bronchial biopsy histological features were consistent with benign metastasizing leiomyoma. The patient was successfully treated with argon-plasma and mechanical debulking. There was no disease relapse in the last four years

Global optimal eBURST analysis of multilocus typing data using a graphic matroid approach

<p>Abstract</p> <p>Background</p> <p>Multilocus Sequence Typing (MLST) is a frequently used typing method for the analysis of the clonal relationships among strains of several clinically relevant microbial species. MLST is based on the sequence of housekeeping genes that result in each strain having a distinct numerical allelic profile, which is abbreviated to a unique identifier: the sequence type (ST). The relatedness between two strains can then be inferred by the differences between allelic profiles. For a more comprehensive analysis of the possible patterns of evolutionary descent, a set of rules were proposed and implemented in the eBURST algorithm. These rules allow the division of a data set into several clusters of related strains, dubbed clonal complexes, by implementing a simple model of clonal expansion and diversification. Within each clonal complex, the rules identify which links between STs correspond to the most probable pattern of descent. However, the eBURST algorithm is not globally optimized, which can result in links, within the clonal complexes, that violate the rules proposed.</p> <p>Results</p> <p>Here, we present a globally optimized implementation of the eBURST algorithm – goeBURST. The search for a global optimal solution led to the formalization of the problem as a graphic matroid, for which greedy algorithms that provide an optimal solution exist. Several public data sets of MLST data were tested and differences between the two implementations were found and are discussed for five bacterial species: <it>Enterococcus faecium</it>, <it>Streptococcus pneumoniae</it>, <it>Burkholderia pseudomallei</it>, <it>Campylobacter jejuni </it>and <it>Neisseria spp.</it>. A novel feature implemented in goeBURST is the representation of the level of tiebreak rule reached before deciding if a link should be drawn, which can used to visually evaluate the reliability of the represented hypothetical pattern of descent.</p> <p>Conclusion</p> <p>goeBURST is a globally optimized implementation of the eBURST algorithm, that identifies alternative patterns of descent for several bacterial species. Furthermore, the algorithm can be applied to any multilocus typing data based on the number of differences between numeric profiles. A software implementation is available at <url>http://goeBURST.phyloviz.net</url>.</p

Distributing Multipartite Entanglement over Noisy Quantum Networks

A quantum internet aims at harnessing networked quantum technologies, namely by distributing bipartite entanglement between distant nodes. However, multipartite entanglement between the nodes may empower the quantum internet for additional or better applications for communications, sensing, and computation. In this work, we present an algorithm for generating multipartite entanglement between different nodes of a quantum network with noisy quantum repeaters and imperfect quantum memories, where the links are entangled pairs. Our algorithm is optimal for GHZ states with 3 qubits, maximising simultaneously the final state fidelity and the rate of entanglement distribution. Furthermore, we determine the conditions yielding this simultaneous optimality for GHZ states with a higher number of qubits, and for other types of multipartite entanglement. Our algorithm is general also in the sense that it can optimise simultaneously arbitrary parameters. This work opens the way to optimally generate multipartite quantum correlations over noisy quantum networks, an important resource for distributed quantum technologies.Comment: More detailed calculations of the metrics and minor changes. Keywords: Quantum Internet, QLANs, Multipartite Entanglement, Entanglement Distribution, Multi-objective Routing, Quantum Network

Entanglement Routing Based on Fidelity Curves for Quantum Photonics Channels

The quantum internet promises to extend entanglement correlations from nearby neighbors to any two nodes in a network. How to efficiently distribute entanglement over large-scale networks is still an open problem that greatly depends on the technology considered. In this work, we consider quantum networks composed of photonic channels characterized by a trade-off between the entanglement generation rate and fidelity. For such networks we look at the two following problems: the one of finding the best path to connect any two given nodes in the network bipartite entanglement routing, and the problem of finding the best starting node in order to connect three nodes in the network multipartite entanglement routing. We consider two entanglement distribution models: one where entangled qubit are distributed one at a time, and a flow model where a large number of entangled qubits are distributed simultaneously. We propose the use of continuous fidelity curves (i.e., entanglement generation fidelity vs rate) as the main routing metric. Combined with multi-objective path-finding algorithms, the fidelity curves describing each link allow finding a set of paths that maximize both the end-to-end fidelity and the entanglement generation rate. For the models and networks considered, we prove that the algorithm always converges to the optimal solution, and we show through simulation that its execution time grows polynomial with the number of nodes in the network. Our implementation grows with the number of nodes with a power between $1$ and $1.4$ depending on the network. This work paves the way for the development of path-finding algorithms for networks with complex entanglement distribution protocols, in particular for other protocols that exhibit a trade-off between generation fidelity and rate, such as repeater-and-purify protocols

Distributing multipartite entanglement over noisy quantum networks

A quantum internet aims at harnessing networked quantum technologies, namely by distributing bipartite entanglement between distant nodes. However, multipartite entanglement between the nodes may empower the quantum internet for additional or better applications for communications, sensing, and computation. In this work, we present an algorithm for generating multipartite entanglement between different nodes of a quantum network with noisy quantum repeaters and imperfect quantum memories, where the links are entangled pairs. Our algorithm is optimal for GHZ states with 3 qubits, maximising simultaneously the final state fidelity and the rate of entanglement distribution. Furthermore, we determine the conditions yielding this simultaneous optimality for GHZ states with a higher number of qubits, and for other types of multipartite entanglement. Our algorithm is general also in the sense that it can optimize simultaneously arbitrary parameters. This work opens the way to optimally generate multipartite quantum correlations over noisy quantum networks, an important resource for distributed quantum technologies.info:eu-repo/semantics/publishedVersio

Pre- and post-COVID practice of interventional pulmonology in adults in Portugal

Funding Information: We thank Prime Focus for providing language help and writing assistance to this article. Publisher Copyright: © 2022 Sociedade Portuguesa de PneumologiaIntroduction and objectives: There is a lack of information regarding bronchoscopy practice in adults in Portugal. Our objective was to obtain an overview of the characteristics, resources, techniques and behaviors in national interventional pulmonology (IP) units, before and after SARS-CoV-2 outbreak. Materials and Methods: An online survey was developed by an expert panel with a total of 46 questions comprising the specifications of each unit, namely physical space, equipment, staff, procedure planning, monitoring, technical differentiation, and numbers pre- and post-COVID-19. Forty-one interventional pulmonology centers were invited to participate between April and May 2021. Results: 37 units (90.2%) responded to the survey. The majority (64.9%) have a fully dedicated space with a weekly presence of ≥3 chest physicians (82.1%) and support of an anesthesiologist on specific days (48.6%). There is marked heterogeneity in the IP unit's equipment, and 56.8% acquired disposable bronchoscopes after COVID-19 pandemics. Pre-bronchoscopy hemogram, platelet count and coagulation tests are regularly asked by more than 90% of the units, even when deep sedation or biopsies are not planned. In 97.3% of cases, topical anesthesia and midazolam are utilized. Propofol (21.6%) and fentanyl (29.7%) are occasionally employed in some institutions. Most units use ancillary sampling techniques to diagnose central or peripheral lesions, with radial EBUS being used for guidance of distal procedures in 37.8% of centers, linear EBUS and EUS-B-FNA for mediastinal diagnosis and/or staging in 45.9% and 27.0% of units, respectively. Cryobiopsies are used by 21.6% of respondents to diagnose diffuse lung diseases. Rigid bronchoscopy is performed in 37.8% of centers. There was a decrease in the number of flexible (p < 0.001) and rigid (p = 0.005) bronchoscopies and an upscale of personal protective equipment (PPE) during the COVID-19 outbreak. Conclusions: IP units have variable bronchoscopic practices, but during the COVID-19 pandemic, they complied with most international recommendations, as elective procedures were postponed and PPE levels increased.proofepub_ahead_of_prin

Selection of trees for rubbing by red and roe deer in forest plantations

Antler rubbing is a form of behaviour by which deer may damage and ultimately induce mortality of trees. Understanding factors affecting selection of trees for rubbing may contribute to mitigation of negative effects of such behaviour in plantations or woodlands. We analysed characteristics of trees rubbed by red and roe deer along transects established in plantations of Pinus pinaster (Aiton), Pseudotsuga menziesii (Mirbel) Franco, Betula alba L. and Quercus robur L. in Northeast Portugal. Transects were walked during five sampling periods covering mating seasons of red and roe deer. Red deer preferentially rubbed trees adjacent to the edge of plantations and large clearings whilst roe deer selected those inside plantations within small clearings. There was seasonal segregation in the number of trees rubbed by each deer species with red deer rubbing trees mainly between September and February and roe deer mainly between December and June. Both red and roe deer selected trees with smaller diameter than those of available trees although trees selected by red deer had larger diameters than those selected by roe deer. Roe, but not red deer, tended to avoid trees protected by shrubs. Overall, the selection of trees for rubbing was site-dependent suggesting that generalizations across sites should be made with caution. Mitigating measures, such as deer control, tree protection or provision of alternative rubbing posts should target stands of particular tree species, location of trees in relation to stand clearings and tree size classes.http://www.sciencedirect.com/science/article/B6T6X-4HGM78R-2/1/29fe58190c40581f0716e977b7847d3