THE LEAD TIME TRADE-OFF: THE CASE OF HEALTH STATES BETTER THAN DEATH

The Lead Time Trade-Off (L-TTO) is a variant of the TTO method that tries to overcome some of the problems of the most widely used method (Torrance, 1986) for health states worse than death (SWD). Theoretically, the new method reduces the problems that have been detected when researchers have elicited preferences for SWD. However, several questions remain to be clarified. One of them is the influence of this new method for states better than death (SBD). In this paper we try to shed some light on this issue using a split sample design (n=500). One subsample (n=188) was interviewed using L-TTO and the rest using the traditional TTO (T-TTO). Our results show that the L-TTO produces utilities that are consistently higher than the T-TTO for SBD. Furthermore, the higher the severity the higher the difference between both methods. Another finding is that the L-TTO seems to produce a lower number of SWD. This effect seems to be concentrated in the most severe health states. This implies a violation of additive separability, one of the cornerstones of the QALY model. Our data show that the L-TTO may be different from the T-TTO in more respects than those that were originally intended.Lead Time Trade-Off, QALYs, Discounting, Additive Independece

THE LEAD TIME TRADE-OFF: THE CASE OF HEALTH STATES BETTER THAN DEATH

The Lead Time Trade-Off (L-TTO) is a variant of the TTO method that tries to overcome some of the problems of the most widely used method (Torrance, 1986) for health states worse than death (SWD). Theoretically, the new method reduces the problems that have been detected when researchers have elicited preferences for SWD. However, several questions remain to be clarified. One of them is the influence of this new method for states better than death (SBD). In this paper we try to shed some light on this issue using a split sample design (n=500). One subsample (n=188) was interviewed using L-TTO and the rest using the traditional TTO (T-TTO). Our results show that the L-TTO produces utilities that are consistently higher than the T-TTO for SBD. Furthermore, the higher the severity the higher the difference between both methods. Another finding is that the L-TTO seems to produce a lower number of SWD. This effect seems to be concentrated in the most severe health states. This implies a violation of additive separability, one of the cornerstones of the QALY model. Our data show that the L-TTO may be different from the T-TTO in more respects than those that were originally intended.Lead Time Trade-Off, QALYs, Discounting, Additive Independece

Structure, Control, and Communication of Collective Animal Behavior in Dynamic Environments

Collective behavior in animal aggregations is highly complex and spans multiple spatial scales, across a wide range of environmental conditions. In socially active fish, aggregation into schools is a widespread adaptation that confers a variety of safety benefits. The emergent patterns exhibited by collectively behaving fish schools may be influenced by biotic (i.e. predation) or abiotic (i.e. habitat complexity, turbidity) factors in the local environment. Our knowledge of the ways and extent to which environment variability affects schooling behavior at the collective level is currently limited. In this dissertation, I investigated whether environmental factors influenced the collective behavior of fish schools. I focused on three main questions: (1) does habitat context modulate the collective state of fish schools? (2) does the simultaneous presence of habitat structure and high predation risk influence the collective state of fish schools? (3) do environmental constraints on visual sensory perception affect collective responses to predation? Using advanced field methods to observe schooling behavior in restrictive environmental contexts, question one demonstrated that habitat context, not predation, drives change in the collective state of fish schools, suggesting that the local environment plays a larger role than predation risk in structuring collective behavior. Using the same field method at an anthropogenic structure containing both habitat complexity and increased predation risk, question two shows that collective behavior is influenced by the coupling of the two conditions, in a different manner than with habitat complexity alone. Finally, using a behavioral arena that creates three dimensional virtual environments, question three showed that mechanosensory information becomes prioritized when visual perception is compromised, and that multiple sensory systems can control schooling behavior in conditions where information about the environment is unreliable. As a collective itself, the results of these questions advance our understanding of the role the environment plays on influencing collective animal behavior, and offers insights into this understanding from both a mechanistic and process based perspective

Survey of Inter-satellite Communication for Small Satellite Systems: Physical Layer to Network Layer View

Small satellite systems enable whole new class of missions for navigation, communications, remote sensing and scientific research for both civilian and military purposes. As individual spacecraft are limited by the size, mass and power constraints, mass-produced small satellites in large constellations or clusters could be useful in many science missions such as gravity mapping, tracking of forest fires, finding water resources, etc. Constellation of satellites provide improved spatial and temporal resolution of the target. Small satellite constellations contribute innovative applications by replacing a single asset with several very capable spacecraft which opens the door to new applications. With increasing levels of autonomy, there will be a need for remote communication networks to enable communication between spacecraft. These space based networks will need to configure and maintain dynamic routes, manage intermediate nodes, and reconfigure themselves to achieve mission objectives. Hence, inter-satellite communication is a key aspect when satellites fly in formation. In this paper, we present the various researches being conducted in the small satellite community for implementing inter-satellite communications based on the Open System Interconnection (OSI) model. This paper also reviews the various design parameters applicable to the first three layers of the OSI model, i.e., physical, data link and network layer. Based on the survey, we also present a comprehensive list of design parameters useful for achieving inter-satellite communications for multiple small satellite missions. Specific topics include proposed solutions for some of the challenges faced by small satellite systems, enabling operations using a network of small satellites, and some examples of small satellite missions involving formation flying aspects.Comment: 51 pages, 21 Figures, 11 Tables, accepted in IEEE Communications Surveys and Tutorial

Modelling Noise and Imprecision in Individual Decisions

When individuals take part in decision experiments, their answers are typically subject to some degree of noise / error / imprecision. There are different ways of modelling this stochastic element in the data, and the interpretation of the data can be altered radically, depending on the assumptions made about the stochastic specification. This paper presents the results of an experiment which gathered data of a kind that has until now been in short supply. These data strongly suggest that the 'usual' (Fechnerian) assumptions about errors are inappropriate for individual decision experiments. Moreover, they provide striking evidence that core preferences display systematic departures from transitivity which cannot be attributed to any 'error' story.Error Imprecision Preferences Transitivity

Reinforced column shafts from the monumental architecture of Italica (prov. Baetica). Implementation of new technologies for the reconstruction of an exceptional practice

Esta investigación tiene por objeto presentar los trabajos en curso en torno a un conjunto de fustes procedente de los órdenes arquitectónicos del conocido como Traianeum de Itálica (provincia Baetica, actual Santiponce, Sevilla), complejo de templo central y pórtico perimetral levantado en la ciudad a comienzos del siglo II d. C. En ellos se observan las huellas dejadas por toda una serie de recursos técnicos tales como grapas, espigas metálicas y cavidades para parches marmóreos, asociada con medidas preventivas de refuerzo de piedra eventualmente quebradiza. Para ello, dado su estado fragmentado y fragmentario, se ha recurrido a la aplicación de técnicas fotogramétricas que permitan la obtención de modelos tridimensionales de las piezas, con el fin de reconstruir el funcionamiento y finalidad mecánica de los citados recursos. En último término, se trata de profundizar en aspectos relacionados con una singular capacidad tecnológica selectiva y con la economía y organización de las obras.The pieces under study presented in this paper come from the already well known “Traianeum” of Italica (prov. Baetica, present Santiponce, Seville), a huge complex area, formed by a wide open square with a main central temple, built according to the extension of the city with a new quarter in Hadrian times. Most of them, fragments of column shafts, offer very peculiar technical features: canals for metallic dowels, cavities for marble tasselli and holes for also metallic staples or cramps. All these systems had the aim of reinforce a valuable material with potential structure problems. The ensemble is unique because of the preservation of a sufficient amount of fragments that allows their complete restitution with the help of photogrammetric techniques in order to obtain three-dimensional models of the pieces and to understand the ancient technologic solutions. Even more, the practices make us reflect about technical skills and economy and organization of constructions

Locating the Source of Diffusion in Large-Scale Networks

How can we localize the source of diffusion in a complex network? Due to the tremendous size of many real networks--such as the Internet or the human social graph--it is usually infeasible to observe the state of all nodes in a network. We show that it is fundamentally possible to estimate the location of the source from measurements collected by sparsely-placed observers. We present a strategy that is optimal for arbitrary trees, achieving maximum probability of correct localization. We describe efficient implementations with complexity O(N^{\alpha}), where \alpha=1 for arbitrary trees, and \alpha=3 for arbitrary graphs. In the context of several case studies, we determine how localization accuracy is affected by various system parameters, including the structure of the network, the density of observers, and the number of observed cascades.Comment: To appear in Physical Review Letters. Includes pre-print of main paper, and supplementary materia

The digital transformation of work: a relational view

Conversation about the current and potential effects of digital technologies on the nature of work is raging within scholarly and practitioner communities. Artificial intelligence, robotics, data analytics, digital platforms, and automation, among other technologies, are prompting a swift and profound transformation of work. Building on Pierpaolo Donati''s relational sociology, we examine the changes these technologies are likely to bring about in work as a human relation. Despite the very real threats of unemployment, job insecurity, precariousness, and surveillance, technology may also encourage the emergence of a work culture that shifts the scales toward a relational realm rather than a transactional one. To this end, we argue that work should be understood as a social relation with four dimensions: exchange value, intrinsic extra-economic purpose, communication for reciprocal services, and correspondence with primary human needs according to use values. Understanding the digital transformation of work from this point of view requires comprehending the differentiation and integration of these four dimensions

Por el camino de los imaginarios. La ideología de la ocupación en Chile en el siglo XIX

Durante la segunda mitad del siglo pasado el gobierno chileno ocupó la Araucanía, incorporando definitivamente a su territorio una región que había conservado cierta autonomía. En nuestra opinión se trató de un proceso violento, cuyos efectos pesaron negativamente sobre los mapuches. Su punto de partida habría sido la crisis del 57 y su última expresión, la política reduccional que redujo el escenario en el cual los indígenas se habían conservado. En esta ponencia se examinará el discurso elaborado por los grupos interesados en ocupar la Araucanía con el propósito de demostrar que en el siglo pasado fue imposible que el país abordara el “problema” de Arauco por una vía distinta de la que adoptó. Intentaremos probar también que en este discurso se confunden los intereses económicos con los imaginarios que ciertos sectores sociales han elaborado y socializado en el país. La evidencia documental la encontramos en artículos y comentarios aparecidos en el Ferrocarril de Santiago, El Mercurio de Valparaíso, la Revista Católica y otros escritos de la época (1850 -1860).A modo de síntesis, podríamos adelantar que este discurso contuvo cuatro elementos fundamentales: la idea de la soberanía nacional, la tesis de la raza inferior, el país acosado y ultrajado y la teoría de la raza superior.Sobre la base de estos elementos se presentó la ocupación de la Araucanía como una necesidad que el país no podía postergar. Más allá de esta convicción, expresada con fuerza por sus autores, queremos terminar nuestra exposición haciendo algunos comentarios sobre los desencuentros que han existido en nuestra historia a propósito de nuestra incapacidad para mirarnos como somos y no como lo sugieren nuestras fantasías. Se trata de volver sobre la historia que empieza en el siglo XVI y que, de algún modo, todavía pesa 500 años después del viaje de Colón