1,720,967 research outputs found
Pseudo-prospective earthquake forecasting experiment in Italy based on temporal variation of the b-value of the Gutenberg–Richter law
Full text linkWe present the BVAL method, designed to forecast potentially damaging earthquakes (Mw ≥ 5.0) in Italy based on temporal variations of the b-value of the Gutenberg–Richter frequency–magnitude distribution. The b-value is used as an indicator of stress within the Earth's crust, with lower b-values associated with higher stress levels and an increased likelihood of significant seismic events. This method issues alarms when the b-value falls below a critical threshold. It is optimized using the HOmogenized instRUmental Seismic catalogue data from 1990 to 2004 and validated pseudo-prospectively using data from 2005 to 2022. Our analysis uses the recently developed b-positive (b+) method to compute the b-value from magnitude differences, providing resilience against data incompleteness. We compare the performance of the BVAL method with two established models: the Epidemic Type Aftershock Sequence (ETAS) model, which forecasts earthquake rates based on the epidemic principle that each shock triggers subsequent shocks, and the FORE model, which relies on the occurrence of strong foreshocks. Additionally, we evaluate two ensemble models that combine BVAL and FORE through additive (EADD) and multiplicative (EMUL) strategies to balance false alarms and missed events. The EADD model declares an alarm when either BVAL or FORE signals it, while the EMUL model triggers alarms only when both methods agree. We assess the predictive efficiency of these models using the area skill score, derived from Molchan diagrams, which plot the miss rate against the fraction of space-time occupied by alarms. Our results demonstrate that BVAL is less effective than FORE and ETAS at high space-time fractions, but it outperforms ETAS at low fractions (τ < 2–4 per cent), indicating its potential utility in scenarios where minimizing false alarms is critical. This comprehensive comparison highlights the strengths and limitations of each method, suggesting that integrating multiple forecasting strategies can enhance the reliability of earthquake preparedness and response efforts in Italy
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Homogenization of magnitudes of the ISC Bulletin
Full text linkWe implemented an automatic procedure to download the hypocentral data of the online Bulletin of the International Seismological Centre (ISC) in order to produce in near real-time a homogeneous catalogue of the Global and EuroMediterranean instrumental seismicity to be used for forecasting experiments and other statistical analyses. For the interval covered by the reviewed ISC Bulletin, we adopt the ISC locations and convert the surface wave magnitude (Ms) and short-period body-wave magnitude (mb) as computed by the ISC to moment magnitude (Mw), using empirical relations. We merge the so obtained proxies with real Mw provided by global and EuroMediterranean moment tensor catalogues. For the most recent time interval (about 2 yr) for which the reviewed ISC Bulletin is not available, we do the same but using the preferred (prime) location provided by the ISC Bulletin and converting to Mw the Ms and mb provided by some authoritative agencies. For computing magnitude conversion equations, we use curvilinear relations defined in a previous work and the chi-square regression method that accounts for the uncertainties of both x and y variables
Short-term retrospective forecasting of earthquakes based on temporal variations of the b-value of the magnitude-frequency distribution
No full textVanishing bile duct syndrome in non-Hodgkin lymphoma: a case report
No full textNon-Hodgkin lymphoma (NHL) related vanishing bile duct syndrome (VBDS) is a rare condition that often leads to liver failure and death. A 64-year-old man with history of rheumatic heart disease complicated by steno-aortic insufficiency, mild mitral stenosis, atrial fibrillation, left kidney damage, bilateral glaucoma, left internal jugular vein thrombosis, bronchopneumonia, NHL type B (stage IV) treated with chemo and radiotherapy was admitted to our department for jaundice with predominantly cholestatic component. Liver biopsy allowed a diagnosis of VBDS and patient was treated with ursodesossicolic acid (UDCA) 20 mg/kg/day associated with prednisone 1 mg/kg/day with a transient decrease of bilirubin and cholestasis, but a rapid worsening of general clinical conditions followed by severe acute liver failure (ALF), unresponsive to pharmacological therapy, leads to death our patient. In our case we supposed that this syndrome represents the paraneoplastic epiphenomenon of NHL with severe duct damage, related to lymphomatous release of toxic cytokines. In our clinical practice we must not forget that VBDS can be related to hepatic damage also induced during NHL. A special attention to abnormal liver function is necessary to diagnose this syndrome, because often the tests are interpreted as disseminated (stage IV) disease and not as a possible expression of VBDS which could, in some cases, be attenuated by UDCA and by steroids therapy
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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