Patterns of pain freedom response in 497 cases with classical trigeminal neuralgia and at least one year of follow-up treated by gamma knife radiosurgery

Purpose: To identify patterns of initially pain freedom response in patients with classical trigeminal neuralgia (CTN) with Gamma Knife surgery (GKS) and to compare their associated hypoesthesia and recurrence rates. Methods: In this study we analysed only 497 patients treated between July 1992 and November 2010, with a follow-up longer than 1 year, after excluding megadolichobasilar artery and multiple sclerosis related trigeminal neuralgia, as well as the second GKS treatments so as to have only cases with CTN and single radiosurgical treatment. GKS using a Gamma Knife (model B or C or Perfexion) was performed, based on both MRI and computer tomography (CT) targeting. A single 4-mm isocenter was positioned in the cisternal portion of the trigeminal nerve at a median distance of 7.8 mm (range 4.5-14) anteriorly to the emergence of the nerve. A median maximum dose of 85 Gy (range 70-90) was delivered. After empiric methods but also by using a chart with clear cut-off periods of pain free distribution, we were able to divide the initially pain free patients into 3 separate groups: within the first 48 hours, after 48 hours till 30 days and after 30 days, respectively. Results: The median follow- up period was 43.75 months (range 12-174.41). Four hundred and fifty-four patients (91.75%) were initially pain free in a median time of 10 days (range 1-459): 169 (37.2%) became pain free within the first 48 hours (pf<=48 h), compared to 194 (42.8%) between the 3-rd day and the day 30 (pf (>48 h, <=30 d)), inclusively and 91 (20%) patients after 30 days (pf>30d). Differences in terms of postoperative hypoesthesia were found with a p value of 0.014 as follows: the group pf<=48 h had 18 (13.7%) compared to pf (>48 h, <=30 d) with 30 (19%) and pf>30d with 22 (30.5%) patients developing a postoperative GKS hypoesthesia. One hundred and fifty seven (34.4%) patients initially pain free experienced a recurrence with a median delay of 24 months (range 0.62-150.06). There were no statistically significant differences between the three groups concerning recurrence (p value of 0.515). Conclusions: An important number of patients (169 cases, 37.2%) became pain free in the first 48 hours. Hypoesthesia rate was higher within the group becoming pain free after 30 days with a statistically significant difference between the three populations (p= 0.014). Further analysis will eventually help to elucidate the differences observed among groups.

Unpacking the cognitive map: the parallel map theory of hippocampal function

In the parallel map theory, the hippocampus encodes space with 2 mapping systems. The bearing map is constructed primarily in the dentate gyrus from directional cues such as stimulus gradients. The sketch map is constructed within the hippocampus proper from positional cues. The integrated map emerges when data from the bearing and sketch maps are combined. Because the component maps work in parallel, the impairment of one can reveal residual learning by the other. Such parallel function may explain paradoxes of spatial learning, such as learning after partial hippocampal lesions, taxonomic and sex differences in spatial learning, and the function of hippocampal neurogenesis. By integrating evidence from physiology to phylogeny, the parallel map theory offers a unified explanation for hippocampal function.

Parts, places, and perspectives : a theory of spatial relations based an mereotopology and convexity

This thesis suggests to carry on the philosophical work begun in Casati's and Varzi's seminal book Parts and Places, by extending their general reflections on the basic formal structure of spatial representation beyond mereotopology and absolute location to the question of perspectives and perspective-dependent spatial relations. We show how, on the basis of a conceptual analysis of such notions as perspective and direction, a mereotopological theory with convexity can express perspectival spatial relations in a strictly qualitative framework. We start by introducing a particular mereotopological theory, AKGEMT, and argue that it constitutes an adequate core for a theory of spatial relations. Two features of AKGEMT are of particular importance: AKGEMT is an extensional mereotopology, implying that sameness of proper parts is a sufficient and necessary condition for identity, and it allows for (lower- dimensional) boundary elements in its domain of quantification. We then discuss an extension of AKGEMT, AKGEMTS, which results from the addition of a binary segment operator whose interpretation is that of a straight line segment between mereotopological points. Based on existing axiom systems in standard point-set topology, we propose an axiomatic characterisation of the segment operator and show that it is strong enough to sustain complex properties of a convexity predicate and a convex hull operator. We compare our segment-based characterisation of the convex hull to Cohn et al.'s axioms for the convex hull operator, arguing that our notion of convexity is significantly stronger. The discussion of AKGEMTS defines the background theory of spatial representation on which the developments in the second part of this thesis are built. The second part deals with perspectival spatial relations in two-dimensional space, i.e., such relations as those expressed by 'in front of, 'behind', 'to the left/right of, etc., and develops a qualitative formalism for perspectival relations within the framework of AKGEMTS. Two main claims are defended in part 2: That perspectival relations in two-dimensional space are four- place relations of the kind R(x, y, z, w), to be read as x is i?-related to y as z looks at w; and that these four-place structures can be satisfactorily expressed within the qualitative theory AKGEMTS. To defend these two claims, we start by arguing for a unified account of perspectival relations, thus rejecting the traditional distinction between 'relative' and 'intrinsic' perspectival relations. We present a formal theory of perspectival relations in the framework of AKGEMTS, deploying the idea that perspectival relations in two-dimensional space are four-place relations, having a locational and a perspectival part and show how this four-place structure leads to a unified framework of perspectival relations. Finally, we present a philosophical motivation to the idea that perspectival relations are four-place, cashing out the thesis that perspectives are vectorial properties and argue that vectorial properties are relations between spatial entities. Using Fine's notion of "qua objects" for an analysis of points of view, we show at last how our four-place approach to perspectival relations compares to more traditional understandings.

Virus infection speeds: theory versus experiment

In order to explain the speed of Vesicular Stomatitis Virus VSV infections, we develop a simple model that improves previous approaches to the propagation of virus infections. For VSV infections, we find that the delay time elapsed between the adsorption of a viral particle into a cell and the release of its progeny has a veryimportant effect. Moreover, this delay time makes the adsorption rate essentially irrelevant in order to predict VSV infection speeds. Numerical simulations are in agreement with the analytical results. Our model satisfactorily explains the experimentally measured speeds of VSV infections

Using problem-based learning for introducing producer theory and market structure in intermediate microeconomics

This paper shows how instructors can use the problem‐based learning method to introduce producer theory and market structure in intermediate microeconomics courses. The paper proposes a framework where different decision problems are presented to students, who are asked to imagine that they are the managers of a firm who need to solve a problem in a particular business setting. In this setting, the instructors’ role isto provide both guidance to facilitate student learning and content knowledge on a just‐in‐time basis

El mètode APT (Auto Adjusting Perturbation Theory) de diagonalització de matrius

Es presenta un nou algorisme per a la diagonalització de matrius amb diagonal dominant. Es mostra la seva eficàcia en el tractament de matrius no simètriques, amb elements definits sobre el cos complex i, fins i tot, de grans dimensions. Es posa de manifest la senzillesa del mètode així com la facilitat d'implementació en forma de codi de programació. Es comentenels seus avantatges i característiques limitants, així com algunes de les millores que es poden implementar. Finalment, es mostren alguns exemples numèrics

Conditional compositional biplots: theory and application

The biplot has proved to be a powerful descriptive and analytical tool in many areasof applications of statistics. For compositional data the necessary theoreticaladaptation has been provided, with illustrative applications, by Aitchison (1990) andAitchison and Greenacre (2002). These papers were restricted to the interpretation ofsimple compositional data sets. In many situations the problem has to be described insome form of conditional modelling. For example, in a clinical trial where interest isin how patients’ steroid metabolite compositions may change as a result of differenttreatment regimes, interest is in relating the compositions after treatment to thecompositions before treatment and the nature of the treatments applied. To study thisthrough a biplot technique requires the development of some form of conditionalcompositional biplot. This is the purpose of this paper. We choose as a motivatingapplication an analysis of the 1992 US President ial Election, where interest may be inhow the three-part composition, the percentage division among the three candidates -Bush, Clinton and Perot - of the presidential vote in each state, depends on the ethniccomposition and on the urban-rural composition of the state. The methodology ofconditional compositional biplots is first developed and a detailed interpretation of the1992 US Presidential Election provided. We use a second application involving theconditional variability of tektite mineral compositions with respect to major oxidecompositions to demonstrate some hazards of simplistic interpretation of biplots.Finally we conjecture on further possible applications of conditional compositionalbiplots

Ethical issues of human genetic databases : a challenge to classical health research ethics?

[Contents] - Introduction - Selected existing genetic database : distinctive features, ethical problems and the public debate - The ethical debate : principles, values and interests : the ethical foundations of guidelines - Selected issues of consensus and of controversy - Ethical issues of human genetic databases and the future This book compares the new area of biobanking with the tradition of ethically accepted classical research and highlights the distinctive features of existing databases and guidelines

Role of gene methylation in antitumor immune response: Implication for tumor progression

Cancer immunosurveillance theory has emphasized the role of escape mechanisms in tumor growth. In this respect, a very important factor is the molecular characterization of the mechanisms by which tumor cells evade immune recognition and destruction. Among the many escape mechanisms identified, alterations in classical and non-classical HLA (Human Leucocyte Antigens) class I and class II expression by tumor cells are of particular interest. In addition to the importance of HLA molecules, tumor-associated antigens and accessory/co-stimulatory molecules are also involved in immune recognition. The loss of HLA class I antigen expression and of co-stimulatory molecules can occur at genetic, transcriptional and post-transcriptional levels. Epigenetic defects are involved in at least some mechanisms that preclude mounting a successful host-antitumor response involving the HLA system, tumor-associated antigens, and accessory/co-stimulatory molecules. This review summarizes our current understanding of the role of methylation in the regulation of molecules involved in the tumor immune response.

Caracterización de las células madre neoplásicas en el cáncer de endometrio

El carcinoma de endometrio (CE) es el tumor maligno más frecuente del tracto genital femenino en países desarrollados. Durante los últimos años, ha ganado firmeza la hipótesis de que el origen de los tumores se encuentra en la transformación de células indiferenciadas multipotenciales denominadas células madre somáticas (CMS) en células madre neoplásicas (CSC). Estudios recientes han observado la existencia de células madre en endometrios murinos y humanos; el presente proyecto pretende identificar, aislar, cultivar y caracterizar las CSC endometriales y estudiar los mecanismos moleculares responsables de su transformación. Nuestros resultados muestran que diferentes lineas celulares de cancer de endometrio expresan factores de célula indiferenciada. Un trabajo más extenso con la línea celular Ishikawa muestra la capacidad de estas células para crecer como esferas, diferenciarse a otros linajes y resistir al tratamiento radioterapéutico. Los resultados obtenidos nos permiten pensar que la línea Ishikawa es un buen modelo para el estudio de las CSC endometriales, aunque se necesitaría ampliar el estudio para ser concluyente.

Constraint algorithm for k-presymplectic Hamiltonian systems. Application to singular field theories

The k-symplectic formulation of field theories is especially simple, since only tangent and cotangent bundles are needed in its description. Its defining elements show a close relationship with those in the symplectic formulation of mechanics. It will be shown that this relationship also stands in the presymplectic case. In a natural way,one can mimick the presymplectic constraint algorithm to obtain a constraint algorithmthat can be applied to k-presymplectic field theory, and more particularly to the Lagrangian and Hamiltonian formulations offield theories defined by a singular Lagrangian, as well as to the unified Lagrangian-Hamiltonian formalism (Skinner--Rusk formalism) for k-presymplectic field theory. Two examples of application of the algorithm are also analyzed.

Vectorial capacity, basic reproduction number, force of infection and all that: formal notation to complete and adjust their classical concepts and equations

A dimensional analysis of the classical equations related to the dynamics of vector-borne infections is presented. It is provided a formal notation to complete the expressions for the Ross' Threshold Theorem, the Macdonald's basic reproduction "rate" and sporozoite "rate", Garret-Jones' vectorial capacity and Dietz-Molineaux-Thomas' force of infection. The analysis was intended to provide a formal notation that complete the classical equations proposed by these authors.