Vocal actors within policy and practice contend that environmental variability and shocks, such as drought and prolonged heat waves, drive civil wars in Africa. Recently, a widely publicized scientific article appears to substantiate this claim. This paper investigates the empirical foundation for the claimed relationship in detail. Using a host of different model specifications and alternative...

The diffuse interstellar medium is dynamic, and its chemistry evolution determined by shock fronts as well photodissociation. Shocks are implied the supersonic motions velocity dispersion often statistically called "turbulence". We compare models of magnetohydrodynamic (MHD) shocks, with speeds typical cloud through ISM (3-25 km/s) densities cold neutral gas (~ 100 cm-3), to archival observatio...

Abstract Global assessments of climate extremes typically do not account for the unique characteristics individual crops. A consistent definition exposure specific crops to extreme weather would enable agriculturally-relevant hazard quantification. To this end, we develop a database both temperature and moisture facing by explicitly accounting crop characteristics. this, collate crop-specific p...

abstract comparison of food prices in different periods, indicates fluctuations and continually upward trend. any change in agricultural sector variables, as main food supplier, will affect food price. productivity shocks and production gap are examples of such variables. in this paper ,hodrick prescott and kalman filters are used as generators of productivity shocks and production gap series. ...

The main objective of this paper is to investigate the asymmetric effects of exchangerate on Iranian import price index using quarterly time series data over the period 1990- 2011. For this purpose, positive and negative shocks of the exchange rate have been separated from each other using dummy variables and the effects of the size of the exchange rate shocks by determining a threshold.The emp...