Uncertainties due to imperfect knowledge of systematic effects: general considerations and approximate formulae

Starting from considerations about meaning and subsequent use of asymmetric uncertainty intervals of experimental results, we review the issue of uncertainty propagation. We show that, using a probabilistic approach (the so-called Bayesian approach), all sources of uncertainty can be included in a logically consistent way. Practical formulae for the first moments of the probability distribution are derived up to second-order approximations.Comment: 23 pages, 6 figures. This paper and related work are also available at http://www-zeus.roma1.infn.it/~agostini/prob+stat.htm

YREE determination in seawater. Standardization and validation of a new method based on preconcentration techniques

The most interesting attraction of using rare-earth elements and yttrium (YREE) to address geochemical and marine chemical problems consists of their chemical coherence as group of trace elements. These characters allow YREE compositions of rocks and minerals to be extensively used in studies of provenance, petrogenesis and chemical evolution of the geological materials (1). Similarly, YREE compositions in the hydrosphere were used in studies of coagulation, particle-solution reactions and oceanic circulation of water masses (2-4). Unfortunately, very low concentrations of YREE (ng l-1 or sub-ng l-1) associated to high ionic strength of seawater always represented the main difficulty to analyse dissolved YREE in marine environment. The first geochemical investigations of YREE contents in seawater were carried out using neutron activation and isotope dilution mass spectrometry that were almost entirely replaced by inductively coupled plasma supplemented by mass spectrometry (ICP-MS) in recent years. This technique offers many advantages including simultaneous analysis of all the elements of series and their quantitative determination with detection limits of the order of ng l-1 if associated to preconcentration techniques (5). To perform ultra-trace YREE analyses in seawater, we developed a preconcentration method based on CHELEX-100 iminodiacetate resin followed by ICP-MS determination (Ref). In this study the YREE behaviour was quantitatively investigated during interactions with ion chelating resin and estimation of composed measurement uncertainty associated to measurements was evaluated with a rigorous metrological approach based on method validation and quality control of YREE data. These goals were achieved using synthetic seawater where YREE had concentrations as occurring in natural seawater samples. Under these conditions good recovery were obtained along the YREE series, ranging from 75%-85% and 90%-100% for heavy REE and Y and light REE, respectively. Composed measurement uncertainty was expressed in terms of precision, recovery uncertainties, reference material uncertainty and instrumental calibration uncertainty. The obtained results were critically discussed on the basis of the different contributions and confirm the quadrupole ICP-MS technique as highly sensitive to determine very low YREE concentrations. REFERENCES 1. S. R. Taylor, S.M. McLennan, The Continental Crust: its Composition and Evolution. Blackwell Scientific Publications, Oxford, 1985). 2. G.J. Piepgras, G.J. Wasserburg, Science 217 (1982) 207. 3. J. Zhang, Y. Nozaki, Geochim. Cosmochim. Acta 60 (1996) 4631. 4. R.H. Byrne, E. Sholkovitz, In: Gschneidner, J.K.A., Eyring, (Eds.), Handbook on the Physics and Chemistry of Rare Earths. Elsevier, New York, (1996) 498-593. 5. P. M\uf6ller, P. Dulski P., J. Luck, Spectrochim. Acta, 47B, 1379

Splenomegaly impacts prognosis in essential thrombocythemia and polycythemia vera: A single center study

Splenomegaly is one of the major clinical manifestations of primary myelofibrosis and is common also in other chronic Philadelphia-negative myeloproliferative neoplasms, causing symptoms and signs and affecting quality of life of patients diagnosed with these diseases. We aimed to study the impact that such alteration has on thrombotic risk and on the survival of patients with essential thrombocythemia and patients with Polycythemia Vera (PV). We studied the relationship between splenomegaly (and its grade), thrombosis and survival in 238 patients with et and 165 patients with PV followed at our center between January 1997 and May 2019

Crustáceos decápodos de fondos de maërl y cascajo de la isla de Alborán (Mediterráneo occidental)

Estudio de las comunidades de crustáceos decápodos de la plataforma continental de la Isla de Alborán, asociadas a fondos de maërl o rodolitos y de "cascajo" o biclastos.El presente estudio se enmarca dentro del proyecto LIFE + INDEMARES, uno de cuyos objetivos ha sido la caracterización de las biocenosis de los hábitats esenciales o vulnerables de la plataforma submarina de la isla de Alborán (Ref.: Fundación Biodiversidad, FB 05/2011, Universidad de Málaga). Los fondos de cascajo han resultado ser más ricos, diversos y con una mayor equirrepartición que los de maërl y con agunas especies raras o muy poco frecuentes, ya sea debido al tipo de fondo - hábitat y/o características hidrológicas de la zona.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Cancer patients requiring interruption of long-term warfarin because of surgery or chemotherapy induced thrombocytopenia: the use of fixed sub-therapeutic doses of low-molecular weight heparin.

No data are available regarding the management of cancer patients requiring interruption of long-term vitamin-K antagonist (VKA) therapy. For this purpose, we tested the efficacy and safety of fixed doses of low-molecular weight heparin (LMWH) in substitution of VKA because of invasive procedures or chemotherapy-induced thrombocytopenia. In cancer patients on VKA, therapy was discontinued 5 ± 1 days before surgery or chemotherapy. Heparin was given at prophylactic dosage in patients at low risk and at fixed subtherapeutic doses (3,800 or 4,000 UI anti-FXa, b.i.d.) in those at high-risk for thrombosis. LMWH was reinitiated 12 hr after surgery and VKA the day after. In patients receiving chemotherapy, LMWH was reinitiated 12/24 hr after obtaining a stable platelet count ≥ 30,000 mmc(3) and VKA after a stable platelet count ≥ 50,000 mmc(3) . Thromboembolism and major bleeding events were recorded from the time of VKA suspension to 30 ± 2 days postprocedure or until the next chemotherapy. Overall, 156 patients (56.4% at low risk and 43.5% at high risk for thrombosis) were enrolled; 34.6% underwent major surgery, 40.4% nonmajor surgery, and 25% chemotherapy. Thrombotic events occurred in five patients [3.2%, 95% confidence interval (CI): 1.41-7.27], four belonging to the high-risk and one to the low-risk group. Major bleeding occurred in five patients (3.2%, 95 CI: 1.41-7.27), all belonging to the high-risk group (three during major surgery and two during chemotherapy). In conclusion, LMWH given at fixed subtherapeutic is a feasible and relatively safe approach for bridging therapy in cancer patients on long-term VK

Bayesian geostatistical modelling for mapping schistosomiasis transmission

Progress has been made in mapping and predicting the risk of schistosomiasis using Bayesian geostatistical inference. Applications primarily focused on risk profiling of prevalence rather than infection intensity, although the latter is particularly important for morbidity control. In this review, the underlying assumptions used in a study mapping Schistosoma mansoni infection intensity in East Africa are examined. We argue that the assumption of stationarity needs to be relaxed, and that the negative binomial assumption might result in misleading inference because of a high number of excess zeros (individuals without an infection). We developed a Bayesian geostatistical zero-inflated (ZI) regression model that assumes a non-stationary spatial process. Our model is validated with a high-quality georeferenced database from western Côte d'Ivoire, consisting of demographic, environmental, parasitological and socio-economic data. Nearly 40% of the 3818 participating schoolchildren were infected with S. mansoni, and the mean egg count among infected children was 162 eggs per gram of stool (EPG), ranging between 24 and 6768 EPG. Compared to a negative binomial and ZI Poisson and negative binomial models, the Bayesian non-stationary ZI negative binomial model showed a better fit to the data. We conclude that geostatistical ZI models produce more accurate maps of helminth infection intensity than the spatial negative binomial one

Percepciones de los futuros docentes respecto al potencial de la ludificación y la inclusión de los videojuegos en los procesos de enseñanza-aprendizaje

El trabajo pretende analizar las percepciones de los estudiantes de los grados de Educación Infantil, Primaria y Pedagogía de distintas universidades españolas y latinoamericanas respecto al potencial y uso de la ludificación en el aula para la mejora de los rendimientos y valorar la inclusión del videojuego en los entornos personales de aprendizaje de dicho alumnado analizando las posibilidades pedagógicas del mismo, el potencial para la creación de comunidades de aprendizaje y las opciones para procesos de transformación social. En este sentido, se perseguía conocer el potencial educativo de la ludificación y la adecuación del uso de videojuegos en las etapas de Educación Infantil y Primaria gracias a las percepciones de los futuros docentes en formación. Para ello se desarrolló un estudio descriptivo mediante una encuesta transversal con una muestra de 197 participantes. Los resultados han sido muy positivos respecto a estas herramientas: los fututos docentes están totalmente convencidos de que la ludificación será una herramienta más que estimulante para el alumnado, considerando que los estudiantes trabajarían en el aula con mayor entusiasmo; además, el uso de videojuegos supondrá una influencia en los discentes que fomente la adquisición de las competencias clave establecidas por la legislación educativa.El treball pretén analitzar les percepcions dels estudiants dels graus d'Educació Infantil, Primària i Pedagogia de diferents universitats espanyoles i llatinoamericanes pel que fa al potencial i ús de la ludificació i els videojocs a l'aula per a la millora dels rendiments, i valorar la inclusió del videojoc en els entorns personals d'aprenentatge de l'alumnat analitzant les possibilitats pedagògiques d'aquest, el potencial per a la creació de comunitats d'aprenentatge i les opcions per a processos de transformació social. En aquest sentit, es persegueix conèixer el potencial educatiu de la ludificació i l'adequació de l'ús de videojocs a les etapes d'Educació Infantil i Primària a partir de les percepcions dels futurs docents. Per fer-ho, es va dur a terme un estudi descriptiu mitjançant la tècnica de l'enquesta transversal amb una mostra de 197 participants. Els resultats i les conclusions han estat molt positius pel que fa a aquestes eines; així, els futures docents estan totalment convençuts que la ludificació serà una eina més que estimulant per a l'alumnat, considerant que els alumnes treballarien a l'aula amb més entusiasme; a més, l'ús de videojocs suposarà una influència en els estudiants que fomentarà l'adquisició de les competències clau establertes per la legislació educativa.This paper analyzes the perceptions of students enrolled in bachelor's degree programs in early childhood education, primary education and pedagogy at various Spanish and Latin American universities regarding the potential use of gamification in classrooms to improve academic performance and evaluate the inclusion of video games in the personal learning environments of these students. The educational possibilities, the potential for the creation of learning communities and the main options for social transformation processes of these teaching tools are analyzed. The article seeks to determine the educational potential of gamification and the appropriate use of video games in pre-school and primary education through the perceptions of future teachers. To this end, a descriptive study using a crosssectional survey with a sample of 197 participants is carried out. The results are very positive regarding these tools: future teachers are fully convinced that gamification is a very stimulating tool for students as it motivates them to work in the classroom. Moreover, the use of video games promotes the acquisition of key competencies established under the educational legislation

A Computer Aided Detection system for mammographic images implemented on a GRID infrastructure

The use of an automatic system for the analysis of mammographic images has proven to be very useful to radiologists in the investigation of breast cancer, especially in the framework of mammographic-screening programs. A breast neoplasia is often marked by the presence of microcalcification clusters and massive lesions in the mammogram: hence the need for tools able to recognize such lesions at an early stage. In the framework of the GPCALMA (GRID Platform for Computer Assisted Library for MAmmography) project, the co-working of italian physicists and radiologists built a large distributed database of digitized mammographic images (about 5500 images corresponding to 1650 patients) and developed a CAD (Computer Aided Detection) system, able to make an automatic search of massive lesions and microcalcification clusters. The CAD is implemented in the GPCALMA integrated station, which can be used also for digitization, as archive and to perform statistical analyses. Some GPCALMA integrated stations have already been implemented and are currently on clinical trial in some italian hospitals. The emerging GRID technology can been used to connect the GPCALMA integrated stations operating in different medical centers. The GRID approach will support an effective tele- and co-working between radiologists, cancer specialists and epidemiology experts by allowing remote image analysis and interactive online diagnosis.Comment: 5 pages, 5 figures, to appear in the Proceedings of the 13th IEEE-NPSS Real Time Conference 2003, Montreal, Canada, May 18-23 200