Metals or Management? Explaining Africa\u27s Recent Economic Growth Spurt

Explanations for Africa\u27s poor long-run growth performance have varied over time. The theories examined include geography (Jeffrey D. Sachs and Andrew Warner 1997); institutions (William Easterly and Ross Levine 1997; Daron Acemoglu, Simon Johnson, and James Robinson 2001, 2002; Nathan Nunn 2007, 2008); health (David Bloom and Sachs 1998; Gregory N. Price 2003); and economic dependency (William Darity 1982). More recently, economists have attempted to explain what The Economist has called Africa\u27s new period of unparalleled economic success (The Economist 2008a, 33). Average annual real GDP growth was 1.8 percent between 1980 and 1989 and increased to 4.4 percent between 2000 and 2005. Per head, real growth in Africa fell by 1.1 percent between 1980 and 1989 and increased 2.1 percent between 2000 and 2005 (World Bank 2007a). This recent reversal of fortune may stem from the broad economic reforms that many African countries instituted during the 1990s, especially macroeconomic stabilization and financial-market liberalization. But it may also be due to the recent boom in international prices of oil, copper, and other primary commodities that constitute a significant fraction of Africa\u27s exports (International Monetary Fund (IMF) 2006). With newly available data extending through 2005, we investigate whether international commodity price increases (our metals hypothesis) or policy reforms (our management hypothesis) have driven Africa\u27s recent performance. In doing so, we supplement existing accounts of Africa\u27s recent success (see Benno J. Ndulu and Stephen A. O\u27Connell 2007; John Page and Jorge S. Arbache 2008, for example). Our results, based on cross-country growth regressions, suggest that both metals and man agement have contributed to Africa\u27s recent reversal of economic fortune

A small open economy New Keynesian model for a foreign exchange constrained economy

Firms in many low income countries depend entirely on imported capital and intermediate inputs. As a result, in these countries economic activity is considerably influenced by the capacity of the economy to import these inputs which, in turn, depends on the availability and cost of foreign exchange. In this study we introduce foreign exchange availability as an additional constraint faced by firms into an otherwise standard small open economy New Keynesian DSGE model. The model is then calibrated for a typical Sub Saharan African economy and the behaviour of the model in response to both domestic and external shocks is compared with the standard model. The impulse responses of the two models show that the modified model generates more variability in most of the variables considered than the standard model. This behaviour of the modified model seems to correspond to the stylized facts of low income countries.New Keynesian DSGE; Foreign exchange constraint; Low income countries; Sub-Saharan Africa

Fiscal policy and stabilization in Brazil

The theoretical basis for the"heterodox shocks"recently implemented in Argentina and Brazil is that chronic inflation is essentially inertial - the product of staggered prices and wage adjustments. The underlying assumption is that the economic process is a cooperative game. Without legal and other forms of coercion, however, individuals tend to cheat - to fix their prices above average to start with. A basic flaw of the"heterodox"stabilization programs was to assume that stabilizing the price level was a precondition for fiscal equilibrium and eventual fiscal reform - instead of the reverse. The fiscal austerity promised after stabilization was never accomplished - blocked by bureaucrats and special interest groups interested in maintaining the status quo. The challenge in these countries is to devise economic programs that could make long-term stabilization programs viable and politically acceptable.Economic Stabilization,Economic Theory&Research,Environmental Economics&Policies,National Governance,Public Sector Economics&Finance

Capital Controls and Foreign Investor Subsidies Implicit in South Africa's Dual Exchange Rate System

Both in theory and practice, capital controls and dual exchange rate systems can be part of a country's optimal tax policy. We first show how a dual exchange rate system can be interpreted as a tax (or subsidy) on international capital income. We show that a dual exchange rate system, with separate commercial and financial exchange rates, drives a wedge between the domestic and foreign returns on comparable assets. As a borrower, the government itself is a direct beneficiary. Secondly, based on data from South Africa, we present empirical evidence of this revenue implicit in a dual exchange rate system; a revenue that amounted to as much as 0.1 percent of GDP for the South African government. However, this paper also shows that both the capital controls and the dual exchange rate system in South Africa gave rise to many perverse unanticipated e¤ects. The latter may render capital controls and dual exchange rate systems unattractive in the end and, thereby, provides a rationale for the recent trend in exchange rate liberalization and unification.Dual exchange rate systems;capital controls;emerging markets;financial repression;optimal tax policy

Functional oxide as an extreme high-k dielectric towards 4H-SiC MOSFET incorporation

MOS Capacitors are demonstrated on 4H-SiC using an octahedral ABO3 ferroic thin-film as a dielectric prepared on several buffer layers. Five samples were prepared: ABO3 on SiC, ABO3 on SiC with a SiO2 buffer (10 nm and 40 nm) and ABO3 on SiC with an Al2O3 buffer (10nm and 40 nm). Depending on the buffer material the oxide forms in either the pyrochlore or perovskite phase. A better lattice match with the Al2O3 buffer yields a perovskite phase with internal switchable dipoles. Hysteresis polarization-voltage loops show an oxide capacitance of ~ 0.2 μF/cm2 in the accumulation region indicating a dielectric constant of ~120

IRVE-II Post-Flight Trajectory Reconstruction

NASA s Inflatable Re-entry Vehicle Experiment (IRVE) II successfully demonstrated an inflatable aerodynamic decelerator after being launched aboard a sounding rocket from Wallops Flight Facility (WFF). Preliminary day of flight data compared well with pre-flight Monte Carlo analysis, and a more complete trajectory reconstruction performed with an Extended Kalman Filter (EKF) approach followed. The reconstructed trajectory and comparisons to an attitude solution provided by NASA Sounding Rocket Operations Contract (NSROC) personnel at WFF are presented. Additional comparisons are made between the reconstructed trajectory and pre and post-flight Monte Carlo trajectory predictions. Alternative observations of the trajectory are summarized which leverage flight accelerometer measurements, the pre-flight aerodynamic database, and on-board flight video. Finally, analysis of the payload separation and aeroshell deployment events are presented. The flight trajectory is reconstructed to fidelity sufficient to assess overall project objectives related to flight dynamics and overall, IRVE-II flight dynamics are in line with expectation

Development of a Rotary Vane Expander for an R-22 Heat Pump System

A traditional vapour compression refrigeration system consists of a compressor, a condenser, a throttling device and an evaporator. The typical throttling devices are capillary tube and expansion valves. Unfortunately, such devices waste expansion energy. To overcome this issue, expanders have been proposed in recent years. An expander can be observed as a compressor operating in a reversed cycle. It expands fluid and produces power which could be used to supply energy to the compressor or other components. The expansion process is more gradual, unlike that in typical throttling devices. Naturally, an expander is most attractive and has been studied most frequently in systems employing a large pressure difference, such as a trans-critical carbon dioxide refrigeration system. Meanwhile, most refrigeration systems in the world are still operating on the conventional Evans-Perkins vapour compression systems. It is, therefore, necessary to study the implementation of expander concept in conventional refrigeration systems. In this study, a rotary vane expander is developed to improve the energy efficiency of an existing R-22 heat pump system. One of the main advantages of rotary vane expanders is it requires no valve to control the fluid flow. The expander is developed by converting a commercially available automotive air conditioning 4-vane rotary compressor. To collect the required design parameters, simulations and experiments are carried out with the heat pump system. The design procedure will be presented and discussed in this paper. Relevant practical issues, such as expansion control will be discussed and addressed

High-Temperature Electrical and Thermal Aging Performance and Application Considerations for SiC Power DMOSFETs

The temperature dependence and stability of three different commercially-available unpackaged SiC Dmosfets have been measured. On-state resistances increased to 6 or 7 times their room temperature values at 350 °C. Threshold voltages almost doubled after tens of minutes of positive gate voltage stressing at 300 °C, but approached their original values again after only one or two minutes of negative gate bias stressing. Fortunately, the change in drain current due to these threshold instabilities was almost negligible. However, the threshold approaches zero volts at high temperatures after a high temperature negative gate bias stress. The zero gate bias leakage is low until the threshold voltage reduces to approximately 150 mV, where-after the leakage increases exponentially. Thermal aging tests demonstrated a sudden change from linear to nonlinear output characteristics after 24-100 h air storage at 300 °C and after 570-1000 h in N2 atmosphere. We attribute this to nickel oxide growth on the drain contact metallization which forms a heterojunction p-n diode with the SiC substrate. It was determined that these state-of-the-art SiC mosfet devices may be operated in real applications at temperatures far exceeding their rated operating temperatures

Evaluation of the levels of renal indices and blood pressure in Type 2 diabetes mellitus, hypertensive and normotensive subjects in Port Harcourt, Nigeria

This study was designed to find out the impact of diabetes mellitus on the renal integrity of diabetic patients following exposure to hypertension and diabetes. This was achieved by examining the urea and creatinine concentrations and creatinine clearance of both diabetics and non-diabetics in Port Harcourt. A total of 165 subjects comprising 32 (19.39%) male diabetics, 53 (31.12%) female diabetics, 48 (29.09%) nondiabetic males and 32 (19.39%) non-diabetic females participated in the study. Results showed that 9.09% of male and 21.91% of female diabetics were hypertensive. Mean urea concentrations obtained were 6.35 ±1.55 mmol/L and 5.56 ± 2.24 mmol/L in the diabetic males and females respectively while in the non-diabetic males and females, the results were 5.66 ± 1.23 mmol/L and 5.07 ± 1.71 mmol/L respectively which was not significantly different (p>0.05, F crit. = 1.98). The creatinine concentration in the diabetic males and females were 93.46 ± 24.97 μmol/L and 89.15 ± 28.01 μmol/L respectively while in the non-diabetic male and female subjects it was 84.64 ± 29.06 μmol/L and 81.69 ± 37.27 μmol/L respectively. These means were not significant (p>0.05, F crit. = 1.65). In both male and female diabetics, the creatinine  clearance was reduced in the subjects following 8 years and above of exposure to diabetes mellitus, which is an indication of commencement of progressive loss of renal function in the diabetic patients. Thus, measurement of creatinine clearance should be included in the routine assessment of renal function especially in type 2 diabetes mellitus patients.Keywords: Renal failure, diabetes mellitus, hyperglycaemia, hypoglycaemia, renal clearance