An Efficient Modified "Walk On Spheres" Algorithm for the Linearized Poisson-Boltzmann Equation

A discrete random walk method on grids was proposed and used to solve the linearized Poisson-Boltzmann equation (LPBE) \cite{Rammile}. Here, we present a new and efficient grid-free random walk method. Based on a modified `` Walk On Spheres" (WOS) algorithm \cite{Elepov-Mihailov1973} for the LPBE, this Monte Carlo algorithm uses a survival probability distribution function for the random walker in a continuous and free diffusion region. The new simulation method is illustrated by computing four analytically solvable problems. In all cases, excellent agreement is observed.Comment: 12 pages, 5 figure

A Fiscal History of Ethiopia: Taxation and Aid Dependence 1960-2010

This paper reviews the fiscal history of Ethiopia, focusing particularly on the period between 1960 and 2010, for which detailed fiscal data is available to underpin the analysis. While reviewing the key fiscal and economic events of this period, particular attention is paid to the relation between Ethiopia and its donors, which in fiscal terms can be seen as a relation between mobilising own tax revenue while negotiating aid and the conditions attached to it. While looking at the main drivers and constraints to tax revenue mobilisation in this period, the paper explores the role that aid and donors have played, and how this historical background influences Ethiopia today

A Review of Tax Experiments: from the Lab to the Field

Tax revenue mobilisation is attracting increasing attention among researchers and policymakers in developed and developing countries alike. There is widespread recognition that increasing tax revenues should be at the core of development strategies, with the aim of reducing dependence on foreign aid, increasing domestic resources to finance development plans, and stimulating transparency and accountability in government–citizen relations. The recent global financial crisis has certainly given momentum to the issue. On the one hand, it made fiscal matters central to the policy debate in developed countries, which resulted in a higher priority in the development debate as well. On the other hand, it made the possibility of scaled-down aid more concrete. For their part, developing countries – and particularly aid-dependent African countries – have been giving higher priority to domestic revenue mobilisation. This has resulted in widespread reforms on the policy side (most notably with the introduction of value added tax, or VAT) and on the administration side (with the establishment of semi-autonomous revenue authorities, among other initiatives, to modernise tax administration).UK Department for International Developmen

Tax revenue mobilisation in Ethiopia

This thesis analyses tax revenue mobilisation in Ethiopia. The main research question motivating the thesis regards the existence of a crowding out effect of foreign aid on domestic public revenue. Throughout the research we are also able to identify other constraints and opportunities for tax revenue mobilisation in Ethiopia, to shed light on broader budget dynamics and to provide firm-level evidence on effective tax rates in the Ethiopian manufacturing sector. The thesis therefore contributes to the current debate on tax revenue mobilisation in Africa by providing comprehensive evidence from Ethiopia, using longer time series than most other studies in this literature. Moreover it provides a new theoretical framework to analyse the aid-tax relation. In addition it contributes to the very small evidence base on taxation at the firm level in Africa by virtually doubling the literature and by proposing a theoretical framework for further research. The thesis starts with a qualitative analysis of the Ethiopian fiscal history between 1960 and 2009. This chapter is based on a descriptive analysis of Ethiopian fiscal data, on the study of secondary sources and on in-depth qualitative interviews. On the basis of this deep understanding of the Ethiopian context, the thesis proceeds by developing a theoretical framework to explain the possible substitution effect between aid and tax. An empirical estimation of the model stemming from the theory shows that aid is positively associated with tax revenues. Other determinants of the tax ratio to GDP are found to be: trade openness, the manufacturing sector, the agricultural sector and governance. The following chapter takes a broader look at budget dynamics by using the cointegrated VAR methodology. The results confirm the positive relation between aid and tax. In addition we find evidence for the existence of a domestic budget equilibrium and for a positive association between aid and capital expenditure in particular. Finally the thesis takes a microeconomic look at taxation by analyzing effective tax rates amongst Ethiopian firms. I find that while tax incentives are widely used in Ethiopia, they do not seem to be affected by lobbying or political connections of the firm

Recensione di Marc Humbert, Yoshimichi Sato (eds), Social Exclusion. Perspectives from France and Japan, Melbourne, Trans Pacific Press, 2012, pages 176, ISBN: 978-1-920901-69-1

A brief introduction of the book "Social Exclusion. Perspectives from France and Japan" edited by Marc Humbert and Yoshimichi Sato: a collection of self contained essays, focused on the crucial theme of the social exclusion from the particular perspective of French and Japanese societie

Collaboration and emotions to the test: the experience of FILe volunteers in hospices​

Abstract. Background and aims: This study seeks to provide an in-depth analysis of care-based interaction in the experiences of volunteers working in lenitherapy (pain therapy) through the case study of hospices in Florence, Italy. Method: A qualitative method of data collection was chosen: the field research made use of open-ended questionnaires distributed to trained but unspecialised volunteers (V = 32) and to volunteers with hospital-based medical expertise (PV = 35) acting for the Italian Lenitherapy Foundation (FILe) and operating in hospices within the ex-ASL (Local Health Unit) of Florence. Results: By analysing the 67 questionnaires collected, it has been possible to reconstruct and interpret the interactional dynamics that exist between the various figures present within a hospice, bringing into focus the most salient aspects of both the organisational context and emotional setting. Conclusions: The research experience, by highlighting everyday unseen aspects that are inaccessible to an ‘internal’ eye, has made it possible to better characterise the dynamics of unsuccessful collaboration between team members and potential areas of conflict. Finally, where these dynamics have been observed, an attempt has been made to outline priorities for change and possible direc- tions to be taken, so as to promote defusing actions and restore synergy and fluidity to the FILe system

Aid and Taxation in Ethiopia

The relation between aid and taxation is largely contested in the literature. On the one hand, aid may act as a substitute for tax revenue and thus have a crowding-out effect. It can also have a detrimental effect on domestic tax institutions. On the other hand, it can promote and support tax mobilisation through policy advice, technical assistance, and conditionality, in addition to more indirect channels. The case of Ethiopia supports the existence of a positive relation between aid and tax, which occurs mainly through policy advice and technical assistance rather than conditionality. This finding is grounded in both quantitative and qualitative analysis

Is Fiscal Decentralisation Delivering on its Promises? A Review of the Theory and Practice in Developing Countries

Fiscal decentralisation has become a widespread phenomenon in developing countries and it has attracted increasing attention in the past few decades. The supporters of decentralisation argue that it can bring about positive outcomes, whether economic or political in nature. For example, since local governments are closer to citizens, they can be expected to be more responsive to their needs. In addition, decentralisation may trigger positive effects in terms of political participation and accountability. Whether these theoretical benefits are achieved in practice is an open question that this paper aims to address. After providing an overview of the main issues and challenges in the design and implementation of fiscal decentralisation, the paper reviews the existing evidence on the impact of fiscal decentralisation on economic and political outcomes at the local level. By doing this it aims to assess whether decentralisation delivered on its promises

A deterministic particle method for one-dimensional reaction-diffusion equations

We derive a deterministic particle method for the solution of nonlinear reaction-diffusion equations in one spatial dimension. This deterministic method is an analog of a Monte Carlo method for the solution of these problems that has been previously investigated by the author. The deterministic method leads to the consideration of a system of ordinary differential equations for the positions of suitably defined particles. We then consider the time explicit and implicit methods for this system of ordinary differential equations and we study a Picard and Newton iteration for the solution of the implicit system. Next we solve numerically this system and study the discretization error both analytically and numerically. Numerical computation shows that this deterministic method is automatically adaptive to large gradients in the solution

What is the Role of Taxpayer Education in Africa?

This paper reviews existing initiatives on taxpayer education in Africa, an area that has been largely under-researched in the literature. We start by providing an overview of the wide variety of programmes that African revenue authorities have undertaken in this area, including both traditional training and more innovative approaches. We then ask how effective these programmes are, and what can be done to improve them in the future. We argue that more evaluation is needed in this area. We also highlight the importance of complementing technical training with broader educational content on the importance of paying taxes, fiscal exchange and transparency.Department for International DevelopmentBill and Melinda Gates Foundatio