Geometry of the Abel Equation of the first kind

We study the first kind Abel differential equation $$\dfrac{dy}{dx}=c_0(x)+3c_1(x)y+3c_2y^2+c_3(x)y^3,$$ where the functions $c_i$ are real analytic. The first step of our analysis is through the Cartan equivalence method, then we use techniques from representation theory; this latter mean allows us to exhibit an affine connection and hence a covariant derivative on the space of differential invariants of the Abel equation. In the context of Abel equation, this affine connection is similar to the connection (also called Frobenius-Stickelberger connexion) given by the quasi-modular Eisenstein series $E_2$, which permits to define a covariant derivative in the space of modular forms and is a solution of a Chazy type equation.Comment: 12 page

Decentralized Managment of Irrigation Areas in the Sahel : Water User Associations in the Senegal River Valley

human development, water, sanitation

A Model of the EFA Liabilities

The authors describe the liabilities model of the Exchange Fund Account (EFA). The EFA is managed using an asset-liability matching framework that requires currency and duration matching of both sides of the balance sheet. The model chooses the mix of liabilities across instruments and tenors that maximizes the return of the fund subject to a fixed asset-allocation rule and duration matching. The model considers two types of instruments: cross-currency swaps and global bonds. The main trade-off in the model is the cost advantage of cross-currency swaps relative to global bond issuance. Cross-currency swaps are, on average, a cheaper source of funding, but carry counterparty risk. The model penalizes a skewed maturity profile of liabilities because it carries rollover risks. The model also reports the implied asset-liability gap, which is a function of the total amount of cross-currency swaps.Debt Management; Foreign reserves management

I2PA : An Efficient ABC for IoT

Internet of Things (IoT) is very attractive because of its promises. However, it brings many challenges, mainly issues about privacy preserving and lightweight cryptography. Many schemes have been designed so far but none of them simultaneously takes into account these aspects. In this paper, we propose an efficient ABC scheme for IoT devices. We use ECC without pairing, blind signing and zero knowledge proof. Our scheme supports block signing, selective disclosure and randomization. It provides data minimization and transactions' unlinkability. Our construction is efficient since smaller key size can be used and computing time can be reduced. As a result, it is a suitable solution for IoT devices characterized by three major constraints namely low energy power, small storage capacity and low computing power

Anharmonic Solutions to the Riccati equation and elliptic modular functions

We study algebraic solutions of the Riccati equation over the field of rational functions $\mathbb C(t)$, and over the elliptic function field $\mathbb C(\wp,\wp^\prime)$

Buoyant Capital Spending and Worries over Real Appreciation: Cold Facts from Algeria

The Government of Algeria has pursed a relatively expansionary fiscal policy in recent years, thanks to rising oil prices and revenues. The paper explores the potential effects of such a stance on real exchange rate and uncovers a relatively small appreciating effect of increased government capital expenditure. This is explained by the fact that a significant share of capital spending falls into tradable imported goods. However, the envisaged increase in capital spending, if well designed and implemented, might in the long-run translate into rising operations and maintenance expenditure—mostly nontradable goods—thereby causing a higher real appreciation. This implies that Algeria should carefully consider the implications of its public investment program on recurrent expenditure.Government capital expenditure;real exchange rate;oil

PUBLIC SPENDING AND REAL EXCHANGE RATE INSTABILITIES AND GROWTH IN AFRICA: EVIDENCE FROM PANEL DATA

The paper investigates the causes of Africa¡¯s poor growth performance. It therefore focuses on the strand of literature that highlights the role of policy instability and uses the dependent economy model as the main theoretical framework. Results from the empirical work indicate that public spending instability increases real exchange rate instability, which in turn exerts a negative impact on both investment and total factor productivity. Further, the empirical investigation suggests partially that real exchange rate appreciation contributes to the decline of sectors with important positive externalities, thereby leading to persistent productivity losses and weak economic growth.Africa, Economic Growth, Macroeconomic Policy, Panel Data

Molecular evidence for the association of a strain of Uganda variant of East African cassava mosaic virus to symptom severity in cassava (Manihot esculenta Crantz) fields in Togo

Abstract: Problem statement: This study was carried out to demonstrate that the severity of Cassava Mosaic Disease (CMD) in Togo, is not only influenced by synergism between cassava Begomoviruses in presence, but essentially by recombination between the different Begomoviruses infecting cassava. Approach: Foliar samples presenting typical biological features of Begomoviruses infection were collected from cassava and wild infected plants from different regions of Togo and analysed by PCR targeting the Coat Protein (CP). The PCR products obtained from different isolates of two major Begomoviruses species infecting cassava in Togo were then sequenced and compared with the sequenced of the African cassava mosaic Begomoviruses identified to date and available in NCBI GenBank database by phylogenetic analysis. Results: The results indicate that not only the two major Begomoviruses could be in synergistic interaction in infected cassava in Togo as it has been shown between African Cassava Mosaic Virus (ACMV) and East African Cassava Mosaic Virus (EACMV) elsewhere, but could also create recombinants which would be highly interfering in the development of symptom severity in the country. Conclusion/Recommendations: The study confirmed the assumption that the symptom severity in cassava fields in Togo is rather caused by recombination between different Begomoviruses in presence than by synergistic interaction. More investigations should be done to give insight to this founding. (Résumé d'auteur