Browse By Author Name - Díez, Francisco J. - e-spacio
http://e-spacio.uned.es/fez/
Universidad Nacional de Educación a DistanciaspFez 2.1 RC3http://blogs.law.harvard.edu/tech/rssArte Rupestre en el Karst de Ojo Guareña (Merindad de Sotoscueva-Burgos) : trabajos de documentación y estudio en «La Sala de La Fuente»
http://e-spacio.uned.es/fez/view/bibliuned:ETFSerie1-AB33324F-1F97-A35D-DD9D-C534D9A796E7
La amplia nómina de autores que
firman el presente artículo dan forma
al equipo multidisciplinar que en 1995
inició un ambicioso proyecto,
subvencionado por la Junta de Castilla
y León, denominado «Trabajos de
Documentación y Estudio del Arte
Rupestre en el Karst de Ojo Guareña».
El avance de sus primeros trabajos
está recogido en el siguiente texto y
fue presentado al Primer Congreso de
Arqueología Burgalesa (1998), mas, al
no haberse publicado éste, sigue aún
inédito. Su interés, y de forma especial
la continuidad de la investigación,
aconseja a los autores su edición en
Espacio, Tiempo y Forma con vistas a
una mayor difusión del proyecto y, con
ello, a un mejor conocimiento de la
grafía rupestre de las galerías
subterráneas del norte de la provincia
de Burgos.The wide number of researchers who
sign the present añide joined in the
multi-discipline team that started an
ambitious project, which was
sponsored by the regional authority:
Junta de Castilla y León, called
«Records and Research on Cave Art
at the karst in Ojo Guareña». The
deveiopment of thelr first researches Is
shown in the present Ítem and it was
also presented in the First Burgos
Archaeology Congress (1998),
although it is still unavailable since it
has never been published. Both, the
Importance of its contents and
specially the continuity of the research
led its authors to publish this article in
Espacio, Tiempo y Forma so that the
project could be widely known and, at
the same time, provide a better
knowledge of rock graphics in the
underground galleries which can be
found in the north of Burgos province.2008-03-27T02:42:02Z
Gómez Barrera, Juan A.
og Ortega Martínez, Ana Isabel
og Martín Merino, Miguel A.
og Fernández Moreno, José J.
og del Val Recio, Jesús
og García Díez, Marcos
og Ruiz García, Francisco
og Latorre González Moro, Pablo
og Cámara Muñoz, Leandro
Cost-effectiveness of Pediatric Bilateral Cochlear Implantation in Spain
http://e-spacio.uned.es/fez/view/bibliuned:95-Jperez-001
Objective: To determine the incremental cost-effectiveness of bilateral versus unilateral cochlear implantation for one-year-old children suffering from bilateral sensorineural severe to profound hearing loss from the perspective of the Spanish public health system. Study Design: Cost-utility analysis. Methods: We conducted a general-population survey to estimate the quality of life increase contributed by the second implant. We built a Markov influence diagram and evaluated it for a life-long time horizon with a 3% discount rate in the base case. Results: The incremental cost-effectiveness ratio (ICER) of simultaneous bilateral implantation with respect to unilateral implantation for one-year-old children with severe to profound deafness is €10,323 per quality-adjusted life year (QALY). For sequential bilateral implantation, it rises to €11,733/QALY. Both options are cost-effective for the Spanish health system, whose willingness to pay is estimated at around €30,000/QALY. The probabilistic sensitivity analysis shows that the probability of bilateral implantation being cost-effective reaches 100% for that cost-effectiveness threshold. Conclusions: Bilateral implantation is clearly cost-effective for the population considered. If possible, it should be done simultaneously, i.e., in one surgical operation, because it is as safe and effective as sequential implantation, and saves costs for the system and for users and their families. Sequential implantation is also cost-effective for children who have received the first implant recently, but it is difficult to determine when it ceases to be so because of the lack of detailed data. These results are specific for Spain but the model can easily be adapted to other countries. Level of Evidence: 2C2020-06-12T06:26:51Z
Pérez-Martín, Jorge
og Artaso, Miguel A.
og Díez, Francisco J.
El Paleolítico Medio en el valle del Arlanza (Burgos). Los sitios de La Ermita, Millán y La Mina
http://e-spacio.uned.es/fez/view/bibliuned:23139
2009-04-03T18:59:56Z
Díez Fernández-Lomana, Juan Carlos
og R. Alonso
og A. Bengoechea
og A. Colina
og Jordá Pardo, Jesús Francisco
og Marta Navazo
og J.E. Ortiz
og S. Pérez
og T. Torres
Evaluation of Markov models with discontinuities
http://e-spacio.uned.es/fez/view/bibliuned:95-Jperez-003
Background. Several methods, such as the half-cycle correction and the life-table method, were developed to attenuate the error introduced in Markov models by the discretization of time. Elbasha and Chhatwal have proposed alternative “corrections” based on numerical integration techniques. They present an example whose results suggest that the trapezoidal rule, which is equivalent to the half-cycle correction, is not as accurate as Simpson’s 1/3 and 3/8 rules. However, they did not take into consideration the impact of discontinuities. Objective. To propose a method for evaluating Markov models with discontinuities. Design. Applying the trapezoidal rule, we derive a method that consists of adjusting the model by setting the cost at each point of discontinuity to the mean of the left and right limits of the cost function. We then take from the literature a model with a cycle length of 1 year and a discontinuity on the cost function and compare our method with other “corrections” using as the gold standard an equivalent model with a cycle length of 1 day. Results. As expected, for this model, the life-table method is more accurate than assuming that transitions occur at the beginning or the end of cycles. The application of numerical integration techniques without taking into account the discontinuity causes large errors. The model with averaged cost values yields very small errors, especially for the trapezoidal and the 1/3 Simpson rules. Conclusion. In the case of discontinuities, we recommend applying the trapezoidal rule on an averaged model because this method has a mathematical justification, and in our empirical evaluation, it was more accurate than the sophisticated 3/8 Simpson rule.2020-06-18T08:29:16Z
Pérez-Martín, Jorge
og Bermejo, Iñigo
og Díez, Francisco J.
Markov influence diagrams: a graphical tool for cost-effectiveness analysis
http://e-spacio.uned.es/fez/view/bibliuned:95-Jperez-002
Markov influence diagrams (MIDs) are a new type of probabilistic graphical models that extend influence diagrams in the same way as Markov decision trees extend decision trees. They have been designed to build state-transition models, mainly in medicine, and perform cost-effectiveness analysis. Using a causal graph that may contain several variables per cycle, MIDs can model various features of the patient without multiplying the number of states; in particular, they can represent the history of the patient without using tunnel states. OpenMarkov, an open-source tool, allows the decision analyst to build and evaluate MIDs—including cost-effectiveness analysis and several types of deterministic and probabilistic sensitivity analysis—with a graphical user interface, without writing any code. This way, MIDs can be used to easily build and evaluate complex models whose implementation as spreadsheets or decision trees would be cumbersome or unfeasible in practice. Furthermore, many problems that previously required discrete event simulation can be solved with MIDs, i.e., within the paradigm of state-transition models, in which many health economists feel more comfortable.2020-06-18T06:57:50Z
Díez, Francisco J.
og Yebra, Mar
og Bermejo, Iñigo
og Palacios-Alonso, Miguel Angel
og Arias Calleja, Manuel
og Luque, Manuel
og Pérez-Martín, Jorge