Agricultural Input Subsidies in Pakistan: Nature and Impact

Pakistan has a history of subsidising agricultural inputs. Although none of the agricultural inputs were subsidised during the early 1950s, the process was initiated in the second half of the decade by subsidising chemical fertilisers in order to popularise their use [Niaz (1984)]. The list of subsidised inputs and the rate structure of the subsidies were expanded considerably throughout the Sixties. Towards the end of the Sixties, it was noted that almost all the agricultural inputs including fertilisers, insecticides, seeds, irrigation water, tubewell installations, and the operation and purchase of tractors and tractor-related equipment were subsidised in one form or another [Aresvik (1967) and Kuhnen (1989)]. In the 1970s, some curtailment of subsidies occurred as a result of input price increases which followed the worldwide recession, a major oil shock, the credit crunch, the war with India, and the consequent steep devaluation of Pakistani Rupee [Chaudhry (1982)]. Although the subsidies had survived the onslaught of the Seventies and tended to persist on most inputs, the government became totally committed to their removal beginning with the 1980s, under pressures from the IMF and the World Bank [Government of Pakistan (1980)]. As a consequence, there was a total withdrawal of subsidy from seeds, insecticides, tubewells, and tractors. A phased-out withdrawal of fertiliser subsidy, culminating in 1984-85 in the case of nitrogenous fertilisers and in 1989-90 in the case of phosphatic and potash fertilisers, was also to be undertaken [World Bank (1986)]. The purpose of the present paper is to highlight the progress of withdrawal of input subsidies in Pakistan, to study the nature of the input subsidies and possibly analyse the impact of the withdrawal of subsidies on the farm sector. Needless to add that the study is also intended to make policy recommendations on the various aspects of subsidy withdrawal.

Longitudinal Seismic Behavior of Earth Dams

Earthquake-induced vibration in earth darns in a direction parallel to the darn axis is studied using analytical elastic models. The non-homogeneity of the darn materials is taken into account by assuming specific variations of the elastic moduli along the depth due to the confining pressure. Based on the models, a rational procedure is developed to estimate dynamic stresses and strains (both shear and normal) and corresponding elastic moduli and damping factors for earth darns from their hysteretic responses to real earthquakes, utilizing the hysteresis loops from the crest and base records. This leads to a study of the variation of stiffness and damping properties with the strain levels of different loops. Finally, an analysis of real earthquake performance of an earth dam, in the longitudinal direction, yields data on the shear moduli, damping factors, and nonlinear constitutive relations for the dam materials; the Ramberg-Osgood nonlinear stress-strain curves are then fitted to these data

Two-dimensional burst identification codes and their use in burst correction

A new class of codes, called burst identification codes, is defined and studied. These codes can be used to determine the patterns of burst errors. Two-dimensional burst correcting codes can be easily constructed from burst identification codes. The resulting class of codes is simple to implement and has lower redundancy than other comparable codes. The results are pertinent to the study of radiation effects on VLSI RAM chips, which can cause two-dimensional bursts of errors

On the existence of optimum cyclic burst-correcting codes

It is shown that for each integer b >= 1 infinitely many optimum cyclic b-burst-correcting codes exist, i.e., codes whose length n, redundancy r, and burst-correcting capability b, satisfy n = 2^{r-b+1} - 1. Some optimum codes for b = 3, 4, and 5 are also studied in detail