Segmentation of Multi-Isotope Imaging Mass Spectrometry Data for Semi-Automatic Detection of Regions of Interest

Multi-isotope imaging mass spectrometry (MIMS) associates secondary ion mass spectrometry (SIMS) with detection of several atomic masses, the use of stable isotopes as labels, and affiliated quantitative image-analysis software. By associating image and measure, MIMS allows one to obtain quantitative information about biological processes in sub-cellular domains. MIMS can be applied to a wide range of biomedical problems, in particular metabolism and cell fate [1], [2], [3]. In order to obtain morphologically pertinent data from MIMS images, we have to define regions of interest (ROIs). ROIs are drawn by hand, a tedious and time-consuming process. We have developed and successfully applied a support vector machine (SVM) for segmentation of MIMS images that allows fast, semi-automatic boundary detection of regions of interests. Using the SVM, high-quality ROIs (as compared to an expert's manual delineation) were obtained for 2 types of images derived from unrelated data sets. This automation simplifies, accelerates and improves the post-processing analysis of MIMS images. This approach has been integrated into “Open MIMS,” an ImageJ-plugin for comprehensive analysis of MIMS images that is available online at http://www.nrims.hms.harvard.edu/NRIMS_ImageJ.php

The working families' tax credit and some European tax reforms in a collective setting

A framework for simplified implementation of the collective model of labor supply decisions is presented in the context of fiscal reforms in the UK. Through its collective form the model accounts for the well known problem of distribution between wallet and purse, a broadly debated issue which has so far been impossible to model due to the limitations of the unitary model of household behavior. A calibrated data set is used to model the effects of introducing two forms of the Working Families’ Tax Credit. We also summarize results of estimations and calibrations obtained using the same methodology on data from five other European countries. The results underline the importance of taking account of the intrahousehold decision process and suggest that who receives government transfers does matter from the point of view of labor supply and welfare of household members. They also highlight the need for more research into models of household behavior