A multi-layered Bayesian network model for structured document retrieval

New standards in document representation, like for example SGML, XML, and MPEG-7, compel Information Retrieval to design and implement models and tools to index, retrieve and present documents according to the given document structure. The paper presents the design of an Information Retrieval system for multimedia structured documents, like for example journal articles, e-books, and MPEG-7 videos. The system is based on Bayesian Networks, since this class of mathematical models enable to represent and quantify the relations between the structural components of the document. Some preliminary results on the system implementation are also presented

Ranking structured documents using utility theory in the Bayesian network retrieval model

In this paper a new method based on Utility and Decision theory is presented to deal with structured documents. The aim of the application of these methodologies is to refine a first ranking of structural units, generated by means of an Information Retrieval Model based on Bayesian Networks. Units are newly arranged in the new ranking by combining their posterior probabilities, obtained in the first stage, with the expected utility of retrieving them. The experimental work has been developed using the Shakespeare structured collection and the results show an improvement of the effectiveness of this new approach

Synchrotron radiation photoionization mass spectrometry of laser ablated species

The present paper describes an experimental apparatus suitable to create and study free clusters by combining laser ablation and synchrotron radiation. First tests on sulfur samples, S, showed the production, through laser ablation, of neutral Sn clusters (n = 1–8). These clusters were ionized using synchrotron radiation at photon energies from 160 eV to 175 eV, across the S 2p core edge. The feasibility of such combined ablation–synchrotron radiation experiments is demonstrated, opening new possibilities on the investigation of free clusters and radical

Completely monotone outer approximations of lower probabilities on finite possibility spaces

Drawing inferences from general lower probabilities on finite possibility spaces usually involves solving linear programming problems. For some applications this may be too computationally demanding. Some special classes of lower probabilities allow for using computationally less demanding techniques. One such class is formed by the completely monotone lower probabilities, for which inferences can be drawn efficiently once their Möbius transform has been calculated. One option is therefore to draw approximate inferences by using a completely monotone approximation to a general lower probability; this must be an outer approximation to avoid drawing inferences that are not implied by the approximated lower probability. In this paper, we discuss existing and new algorithms for performing this approximation, discuss their relative strengths and weaknesses, and illustrate how each one works and performs

Individual patient data meta-analysis of organ failure in acute pancreatitis : protocol of the PANCREA II study

Context Organ failure is a major determinant of mortality in patients with acute pancreatitis. These patients usually requireadmission to high dependency or intensive care units and consume considerable health care resources. Given a low incidence rate of organ failure and a lack of large non-interventional studies in the field of acute pancreatitis, the characteristics of organ failure that influence outcomes of patients with acute pancreatitis remain largely unknown. Therefore, the Pancreatitis Across Nations Clinical Research and Education Alliance (PANCREA) aims to conduct a meta-analysis of individual patient data from prospective non-interventional studies to determine the influence of timing, duration, sequence, and combination of different organ failures on mortality in patients with acute pancreatitis. Methods Pancreatologists currently active with acute pancreatitis clinical research will be invited to contribute. To be eligible for inclusion patients will have to meet the criteria of acute pancreatitis, develop at least one organ failure during the first week of hospitalization, and not be enrolled into an intervention study. Raw data will then be collated and checked. Individual patient data analysis based on a logistic regression model with adjustment for confounding variables will be done. For all analyses, corresponding 95% confidence intervals and P values will be reported. Conclusion This collaborative individual patient data meta-analysis will answer important clinical questions regarding patients with acute pancreatitis that develop organ failure. Information derived from this study will be used to optimize routine clinical management and improve care strategies. It can also help validate outcome definitions, allow comparability of results and form a more accurate basis for patient allocation in further clinical studies

Contrast media-induced nephrotoxicity in uninephrectomized and dehydrated female wistar rats

The present study evaluated renal injury induced by contrast media diatrizoate and lopamidol in uninephrectomized and dehydrated female wistar rats. 22 female Wistar rats were divided into four groups according to the treatment performed: GI – Saline (n=5), GII – Sham (n=5), GIII – diatrizoate (n=5) and GIV – Lopamidol (n=7). The effects induced by contrast media were evaluated by seric levels of creatinine and by descriptive and semi-quantitative renal histopathology. There was no difference in renal function 3 hours after administration of diatrizoate and lopamidol.  Proximal tubular cells vacuolization was proeminent (3+) in lopamidol and diatrizoate group. Therefore, according to renal function evaluation, low-osmolar contrast media was so nephrotoxic as the high-osmolar one.O presente estudo avaliou os danos renais causados pela administração dos contrastes radiológicos diatrizoato de sódio, iônico e hiperosmolar e do lopamidol, não iônico e de baixa osmolaridade, em ratos Wistar fêmeas uni-nefrectomizados e em restrição hídrica. Foram utilizados 22 ratos Wistar fêmeas, sendo divididos em quatro grupos de acordo com o tratamento efetuado: GI – salina (n=5), GII – Sham (n=5), GIII - diatrizoato de sódio (n=5) e GIV – lopamidol (n=7).  Os efeitos produzidos pelos contrastes radiológicos foram avaliados pela dosagem de creatinina sérica e pela histopatologia renal descritiva e semiquantitativa. No 18º dia do experimento, três horas após aplicação intravenosa do contraste diatrizoato (GIII) houve um aumento significativo nos níveis de creatinina sérica em relação aos grupos controles salina (GI) e Sham (GII). Após a administração do lopamidol (GIV) houve um decréscimo no nível de cretinina sérica. No entanto, comparando-se os grupos diatrizoato (GIII) e lopamidol (GIV), no 18º dia, não foi notada diferença estatística na função renal. A vacuolização das células dos túbulos renais foi acentuada (3+) tanto no grupo que recebeu o contraste diatrizoato quanto no grupo lopamidol. Com base na função renal, neste experimento, o contraste de baixa osmolaridade e não iônico mostrou-se tão nefrotóxico quanto o de alta osmolaridade e iônico