A Study of the Efficiency of Small Models in the Projection of Regional Populations

The work described in this paper arose out of an ongoing research project, carried out at IIASA and the Centre for Environmental Studies, London, which aims at a more complete understanding of the dynamics of population movements and regional economic growth. This general study has two main themes. One deals substantively with interurban migration within a system of post-industrial cities, and aims to recast migration from the traditional economic push-pull theory into a more dynamic multicausal theory in which job turnover in the local labour market plays an important part. The second theme is methodological and describes a structured research strategy for the dynamic analysis of complex systems. The study argues that, while it is important to recognize the usefulness of simple models at the early stages of an enquiry, those same simple models should be improved by hypothesis testing during the course of the work; the study argues further that a hierarchy of models of national settlement systems should be developed at varying levels of approximation. At the simplest level, one should be able to perform calculations on the back of an envelope that describe the broad qualitative directions of change in a way that is of interest to policy makers in the short term. In policy analysis, as in everything else, one has to begin in order to begin. But it is equally important to recognize the need for change when the inadequacy of the simpler methods has been demonstrated. Thus policy analysis becomes an iterative, structured learning process. Within this general context, this paper aims to illustrate and test some simple models for calculating differential rates of population change which require little data or time to construct, but which may be useful in preliminary explorations of policy. The paper focuses on the regional population distributions of France; a companion paper by David Gleave entitled "The Utility and Compatibility of Simple Migration Models" considers the application of similar methods in the UK, Italy, the Federal Republic of Germany and France

Analyse de la survie des volumineux mélanomes uvéaux postérieurs traités par énucléation primaire

LYON1-BU Santé (693882101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Major cytogenetic aberrations and typical multidrug resistance phenotype of uveal melanoma: Current views and new therapeutic prospects

International audienceUveal melanoma is the most frequent intra-ocular cancer. The recent development of new chromosome-related technologies have permitted the elucidation of both the cytogenetics and the natural history of this disease. Fifty to 60% of uveal melanomas are linked to a monosomy 3, which appears as an early and determinant event in tumor progression. Tumors with this anomaly have a very poor prognosis. Recent work suggests that this category of uveal melanoma represents a distinct pathologic entity from that associated with normal disomy 3. Chromosome 6 aberrations probably constitute a second entry point into the process of cancerogenesis, while gains in 8q seem to appear later in the natural history of uveal melanomas due to their higher frequency in larger tumors. Other anomalies will be reviewed. In spite of significant improvements in the local treatment of uveal melanoma, many patients die due to tumor metastasis. This disease is characterized by a constitutive chemoresistance whose typical multidrug resistance phenotype (MDR) is particularly complex since different combinations of several resistance proteins are simultaneously produced. Regulation of the expression of these proteins is a research priority, increasingly so as gene therapy-dependent chemosensitization strategies expand. Therefore, the development and improvement of methods to determine the chemoresistance profile become a crucial objective today in the therapeutic strategies against uveal melanoma

Epistaxis or epiphora as a sign for extension of a conjunctival melanoma. A series of six patients with nasolacrimal recurrence

Purpose To characterise malignant conjunctival melanomas with extension and recurrence in the nasolacrimal system. Methods Localisation of the primary tumour and recurrences of 210 conjunctival melanomas treated in The Netherlands were reviewed for orbital and nasal tumours (1978-2008). Based of these cases and literature data, characteristics for nasolacrimal system extension and metastasis were reviewed. Results Six patients (3%) showed a recurrence of the primary conjunctival melanoma in the nasolacrimal system. Two of the six primary tumours were limbal tumours; the other four were diffuse tumours involving the fornix. In all six patients, the primary conjunctival melanomas were associated with primary acquired melanosis. During the follow-up period (11.6 +/- 3 years, range 3.4-28.5 years, median 8.7 years) two patients developed metastases and died. Conclusions Patients should be advised to contact their treating ophthalmologist in the case of symptoms of epiphora, nose obstructions and epistaxis, especially non-bulbar and diffuse cases associated with primary acquired melanosis.Ophthalmic researc