The Rise and Fall of the Ebro Water Transfer

This article analyzes the Ebro inter-basin transfer, which was the main project of the Spanish National Hydrological Plan. The Ebro transfer was prompted by pervasive pressures, scarcity and degradation of Southeastern basins in Spain. The heated policy debate on the Ebro transfer, highlights the difficulties of achieving a sustainable water management, because of the conflicting interests of stakeholders and regions. Alternatives to the Ebro transfer show that, acceptable outcomes combine demand and supply measures. Nevertheless, implementation could be difficult and requires compensation to farmers, otherwise an excessive burden on farmers would be met by social opposition leading to the failure of measures

A comparative analysis between two statistical deviation–based consensus measures in group decision making problems

The mean absolute deviation and the standard deviation, two statistical measures commonly used in quantifying variability, may become an interesting tool when defining consensus measures. Two consensus indexes which obtain the level of consensus in some problems of Group Decision Making are introduced in this paper by expanding the aforementioned statistical concepts. A comparative analysis reveals that the levels of consensus derived from these indexes are close to those obtained employing distance functions when a fuzzy preference relations frame is considered, so they turn out to be a useful tool in this context. In addition, these indexes are different from each other and with the distance functions considered. Thus, they are applicable tools in the calculation of consensus in our context and are different from those commonly used

Design of a resistojet for Space Station Freedom

In the mid 1990's, NASA will begin assembly of Space Station Freedom, a permanent outpost in a low-earth orbit. For the station to remain in that orbit, an altitude control system must be developed to resist the effects of atmospheric drag. One system being considered by NASA is called a resistojet, and it uses highly pressurized waste gases heated by electrical resistance to provide thrust on the order of 1 Newton. An additional function of the resistojet is to vent waste gases used by the station and its inhabitants. This report focuses on resolving the issues of system performance, flow and heater control, and materials selection and designing test procedures to resolve, by experimentation, any remaining issues. The conceptual model of the resistojet consists of a shell wrapped by a resistive coil with gases flowing internally through the tube with additional components such as regulators, transducers, and thermocouples. For system performance, the major parameters were calculated from the desired thrust range, the pressure within the resistojet and the cold flow mode of operation; waste gases were analyzed at 100 percent capacity and between 58.95 kPa and 552 kPa. The design team found that any ventilation under all conditions would produce thrust, and therefore, it was decided to limit the design of the ventilation function. The design team proceeded with a simplified model to determine the nozzle throat diameter and chamber diameter

Profits encourage investment, investment dampens profits, government spending does not prime the pump — A DAG investigation of business-cycle dynamics

NIPA data of the US economy for the years 1929-2013 are used to test major views about the business cycle. Direct acyclic graphs (DAGs) are used for identification purposes, i.e., as tool to elucidate causal issues. Results show that (a) investment is not autonomous, as it is stimulated by profits and consumption, and damped by government spending; (b) profits are reduced by past investment; (c) government spending appears as an endogenous variable, as both business investment and profits have negative effects on it. Regularities identified in the data are sufficient to generate the cycle. Considering the results, the “regularity” of the business cycle, and the fact that profits stagnated in 2013 and declined in 2014 after growing between 2008 and 2012, it can be concluded with reasonable confidence that a recession will occur in the next few years

Oil prices and the world business cycle: A causal investigation

Oil shocks have been often considered as exogenous factors responsible of economic downturns. In this paper the hypothesized exogeneity of oil prices is investigated by using running cross-correlations, distributed lag-regressions, Granger causality tests and VAR models applied to annual data 1960-2014 of oil prices and global economic activity—as measured by world GDP. Strong evidence is found that (a) the relation between oil prices and the global economy has significantly changed since the 1960s to the present, and (b) oil prices are endogenously influenced by the level of activity in the global economy. Evidence of a negative effect of oil prices on the global economy is weak for the whole sample and null for recent decades. These findings are consistent with former results using the Kilian index, which is shown to be a leading indicator of activity in the world economy. As such it is significantly correlated with other indicators of the global business cycle, such as the rate of growth of world output and the annual growth of CO2 global emissions

Oil prices and the world business cycle: A causal investigation

Oil shocks have been often considered as exogenous factors responsible of economic downturns. In this paper the hypothesized exogeneity of oil prices is investigated by using running cross-correlations, distributed lag-regressions, Granger causality tests and VAR models applied to annual data 1960-2014 of oil prices and global economic activity—as measured by world GDP. Strong evidence is found that (a) the relation between oil prices and the global economy has significantly changed since the 1960s to the present, and (b) oil prices are endogenously influenced by the level of activity in the global economy. Evidence of a negative effect of oil prices on the global economy is weak for the whole sample and null for recent decades. These findings are consistent with former results using the Kilian index, which is shown to be a leading indicator of activity in the world economy. As such it is significantly correlated with other indicators of the global business cycle, such as the rate of growth of world output and the annual growth of CO2 global emissions

Profits encourage investment, investment dampens profits, government spending does not prime the pump — A DAG investigation of business-cycle dynamics

Major views about the business cycle are tested by using NIPA data of the US economy for the years 1929-2013. Direct acyclic graphs (DAGs) are used for identification purposes, i.e., as tool to elucidate causal issues. Re-sults show that (a) investment is not autonomous, as it is stimulated by profits and consumption, and damped by government spending; (b) profits are reduced by past investment; (c) both business investment and profits have negative effects on government spending which consequently appears as an endogenous rather than as an exogenous variable. Regularities identified in the data are sufficient to generate the cycle. Considering the results, the “regularity” of the business cycle, and the fact that after growing between 2008 and 2012, profits stagnated in 2013 and declined in 2014, it can be concluded with reasonable confidence that a recession will occur in the next few years