1,197 research outputs found

    On the Probability and Severity of Ruin

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    In the usual model of the collective risk theory, we are interested in the severity of ruin, as well as its probability. As a quantitative measure, we propose G(u, y), the probability that for given initial surplus u ruin will occur and that the deficit at the time of ruin will be less than y, and the corresponding density g(u, y). First a general answer in terms of the transform is obtained. Then, assuming that the claim amount distribution is a combination of exponential distributions, we determine g; here the roots of the equation that defines the adjustment coefficient play a central role. An explicit answer is also given in the case in which all claims are of constant siz

    Effect of shear stress on Pseudomonas aeruginosa isolated from the cystic fibrosis lung

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    Chronic colonization of the lungs by Pseudomonas aeruginosa is one of the major causes of morbidity and mortality in cystic fibrosis (CF) patients. To gain insights into the characteristic biofilm phenotype of P. aeruginosa in the CF lungs, mimicking the CF lung environment is critical. We previously showed that growth of the non-CF-adapted P. aeruginosa PAO1 strain in a rotating wall vessel, a device that simulates the low fluid shear (LS) conditions present in the CF lung, leads to the formation of in-suspension, self-aggregating biofilms. In the present study, we determined the phenotypic and transcriptomic changes associated with the growth of a highly adapted, transmissible P. aeruginosa CF strain in artificial sputum medium under LS conditions. Robust self-aggregating biofilms were observed only under LS conditions. Growth under LS conditions resulted in the upregulation of genes involved in stress response, alginate biosynthesis, denitrification, glycine betaine biosynthesis, glycerol metabolism, and cell shape maintenance, while genes involved in phenazine biosynthesis, type VI secretion, and multidrug efflux were downregulated. In addition, a number of small RNAs appeared to be involved in the response to shear stress. Finally, quorum sensing was found to be slightly but significantly affected by shear stress, resulting in higher production of autoinducer molecules during growth under high fluid shear (HS) conditions. In summary, our study revealed a way to modulate the behavior of a highly adapted P. aeruginosa CF strain by means of introducing shear stress, driving it from a biofilm lifestyle to a more planktonic lifestyle. IMPORTANCE: Biofilm formation by Pseudomonas aeruginosa is one of the hallmarks of chronic cystic fibrosis (CF) lung infections. The biofilm matrix protects this bacterium from antibiotics as well as from the immune system. Hence, the prevention or reversion of biofilm formation is believed to have a great impact on treatment of chronic P. aeruginosa CF lung infections. In the present study, we showed that it is possible to modulate the behavior of a highly adapted transmissible P. aeruginosa CF isolate at both the transcriptomic and phenotypic levels by introducing shear stress in a CF-like environment, driving it from a biofilm to a planktonic lifestyle. Consequently, the results obtained in this study are of great importance with regard to therapeutic applications that introduce shear stress in the lungs of CF patients

    Neural Networks for Target Selection in Direct Marketing

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    Partly due to a growing interest in direct marketing, it has become an important application field for data mining. Many techniques have been applied to select the targets in commercial applications, such as statistical regression, regression trees, ne

    Pattern-Based Target Selection Applied to Fund Raising

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    This paper proposes a new algorithm for target selection. This algorithm collects all frequent patterns (equivalent to frequent item sets) in a training set. These patterns are stored e?ciently using a compact data structure called a trie. Fo

    AUK: a simple alternative to the AUC

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    The area under Receiver Operating Characteristic (ROC) curve, also known as the AUC-index, is commonly used for ranking the performance of data mining models. The AUC has many merits, such as objectivity and ease of interpretation. However, since it is class indifferent, its usefulness while dealing with hig

    A General Framework for Sound and Complete Floyd-Hoare Logics

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    This paper presents an abstraction of Hoare logic to traced symmetric monoidal categories, a very general framework for the theory of systems. Our abstraction is based on a traced monoidal functor from an arbitrary traced monoidal category into the category of pre-orders and monotone relations. We give several examples of how our theory generalises usual Hoare logics (partial correctness of while programs, partial correctness of pointer programs), and provide some case studies on how it can be used to develop new Hoare logics (run-time analysis of while programs and stream circuits).Comment: 27 page

    Towards a Generic Model for MU-MIMO Analysis Including Mutual Coupling and Multipath Effects

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    A network model which accounts for antenna mutual coupling and multipath effects in a wireless channel is proposed as a tool to qualitatively evaluate the performance of a multi-user multiple-input multiple-output (MU-MIMO) system. The system performance is assessed when a zero-forcing (ZF) beamformed conventional uniform linear array (ULA) and a sparse array are employed as one sector of a base station antenna (BSA) in a single-cell network. It is shown that highly correlated user equipments (UEs) in a line-of-sight (LOS) scenario can be decorrelated to some extents, by a scattering environment in a non-line-of-sight (NLOS) scenario. This occurs due to increase of the spatial variation by a multipath effect. Furthermore, in both environments a sparse array realized by an increased interelement spacing is also capable for correlation reduction among users due to the narrower beams

    Psychotropic drug treatment for agitated behaviour in dementia:what if the guideline prescribing recommendations are not sufficient? A qualitative study

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    BACKGROUND: Agitation is a common challenging behaviour in dementia with a negative influence on patient's quality of life and a high caregiver burden. Treatment is often difficult. Current guidelines recommend restrictive use of psychotropic drug treatment, but guideline recommendations do not always suffice. OBJECTIVE: To explore how physicians decide on psychotropic drug treatment for agitated behaviour in dementia when the guideline prescribing recommendations are not sufficient. METHODS: We conducted five online focus groups with a total of 22 elderly care physicians, five geriatricians and four old-age psychiatrists, in The Netherlands. The focus groups were thematically analysed. RESULTS: We identified five main themes. Transcending these themes, in each of the focus groups physicians stated that there is 'not one size that fits all'. The five themes reflect physicians' considerations when deciding on psychotropic drug treatment outside the guideline prescribing recommendations for agitated behaviour in dementia: (1) 'reanalysis of problem and cause', (2) 'hypothesis of underlying cause and treatment goal', (3) 'considerations regarding drug choice', (4) 'trial and error' and (5) 'last resort: sedation'. CONCLUSION: When guideline prescribing recommendations do not suffice, physicians start with reanalysing potential underlying causes. They try to substantiate and justify medication choices as best as they can with a hypothesis of underlying causes or treatment goal, using other guidelines, and applying personalised psychotropic drug treatment
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