The Impact of Institutional Credit on Agricultural Production in Pakistan

Three main factors that contribute to agricultural growth are the increased use of agricultural inputs, technological change and technical efficiency. Technological change is the result of research and development efforts, while technical efficiency with which new technology is adopted and used more rationally is affected by the flow of information, better infrastructure, availability of funds and farmers’ managerial capabilities. Higher use and better mix of inputs also requires funds at the disposal of farmers. These funds could come either from farmers’ own savings or through borrowings. In less developed countries like Pakistan where savings are negligible especially among the small farmers, agricultural credit appears to be an essential input along with modern technology for higher productivity.

The Impact of Institutional Credit on Agricultural Production in Pakistan

Agricultural credit plays an important role in enhancing the agricultural productivity in developing countries like Pakistan. The study discusses various indicators of agricultural credit in Pakistan and presents results of estimated production function using institutional credit as one of the explanatory variables. Over the years, increased percentage of agricultural GDP has been disbursed as institutional credit. During the study period disbursement of institutional credit per cropped hectare also depicted an increasing trend in nominal terms. However, it declined in real terms from late 1980’s to early 1990s. Zarai Taraqiati Bank Limited (ZTBL)-- formerly known as Agricultural Development Bank of Pakistan (ADBP), provides the major share of institutional credit. The share of production loans in total loan advanced has been increasing during 1980-81 to 1986-87 and after mid 1990’s. It shows multiple shifts in credit policy from loans for fixed capital to advances for operational capital during the study period. The OLS estimates of the production function revealed that institutional credit affects agricultural production positively. Water availability at the farm gate, labor, and cropping intensity are the other important variables that affect agricultural output positively. However, the shocks like floods, cotton leaf curl virus (CLCV), and drought have caused significant decline in agricultural output during certain years.institutional credit; agricultural production; production function

Monte Carlo Modelling for Photon and Proton Therapy in Heterogenous Tissue and Prosthesis Material

Treatment outcomes in radiotherapy can be improved by reducing uncertainties in patient set-up, beam delivery and dose distribution. Clarification of arrangements can minimize the dose distributed to normal tissues, and facilitate dose escalation. However, heterogeneity can increase any ambiguities associated with dose distribution. The treatment planning system (TPS) cannot effectively calculate dose distribution in complex heterogeneous areas, which increases uncertainty. This research aims to study microscopic dose distribution in temporal bone, cochlea and pancreatic stents as applicable to modern radiotherapy treatments. To achieve this aim a multiscale approach will be used, as it provides essential information about differences in dose distribution between TPS/clinical CT and Monte Carlo (MC)/Micro CT for photons and protons. In the first part of this study, two DICOM series of pancreatic cancer patients were used with an inserted stent. A new model includes the atomic composition of the stent material, and new stent contouring was introduced to overcome a CT artefact. A PRIMO Monte Carlo model was tuned and compared with the TPS dose distribution and a one-beam volume-modulated arc therapy (VMAT) plan was created. A significant dose difference was observed when comparing the new model and TPS, suggesting increased uncertainty of the dose distribution in clinical practice. An open-access DICOM format of the data for the resected temporal bone and cochlea tissue was used with the FLUKA MC code to imitate potential high-dose scenarios associated with VMAT using the FLOOD option. Twenty-three photon and proton energy levels ranging from 0.055 to 5.5 MeV for photons and 37.59 to 124.83 MeV for protons were simulated separately to calculate dose distribution. Micro CT data shows three density levels in the temporal bone and cochlea. The photon distribution in the low energy range 0.055-0.09 MeV, the largest proportion of the dose (48.8%) was deposited within high-density bone, whereas above 0.125 MeV, the change on dose distribution started to occur where there was greater deposition in low-density tissue, reaching 53%. The dose distribution in the soft bone's intermediate density was 26.4% at 0.07 MeV and dropped to 19.7% at 2.5 MeV. There is a 29% percentage difference in dose distribution on the soft bone between the low and high energy. The dose distribution did not change significantly in proton between the low, intermediate and high-density areas. The dose distribution in 37.59 MeV shows 54.86% in low density, 19.75% in intermediate density and 25.39% in high density. A similar outcome was observed in high energy 124.83 MeV, a dose distribution was 54.21% in low density, 19.79% intermediate density and 26% in high density.An advanced model was created to connect the results to a clinical routine when treating brain tumours using the VMAT technique. Cases were selected from 280 data sets of patients diagnosis with gliomas. Eleven different scenarios were identified. The advanced model shows five cases with an enhanced mean dose. The TPS overestimated the mean dose in all cases. In some instances, A significant mean dose variance of 8.8% was noticed in two cases. Extra cases were selected with a distance between the target and cochlea less than 1 cm. The cases show a significant difference in the mean dose and normal tissue complication probability (NTCP) models. A model was created to connect the results with Gamma Knife treatment. Thirty-four cases of schwannoma were used, and four revealed a significant difference in the scattering dose to the cochlea. The maximum difference in mean dose achieved reached 8.3%.Uncertainty due to dose distribution can affect treatment outcomes. For example, hearing loss and tinnitus can be side effects of brain cancer radiotherapy treatment. It was found that increasing the dose led to a corresponding increased dose reaching the cochlea. Increasing the model accuracy using micro-CT data and MC computation helps to control the dose to the cochlea by controlling dose distribution. In addition, pancreatic cancer can help achieve higher dose escalation to provide better outcomes to patients. Using dose-to-medium calculation, manufactures data associated with stent materials, and models based on Micro CT of resected organs can reveal uncertainty in dose distribution in heterogeneous areas

Higher Dimensional Inhomogeneous Perfect Fluid Collapse in \emph{f(R)} Gravity

This paper is about the $n+2$-dimensional gravitational contraction of inhomogeneous fluid without heat flux in the framework of $f(R)$ metric theory of gravity. Matching conditions for two regions of a star has been derived by using the Darmois junction conditions. For the analytic solution of equations of motion in modified $f(R)$ theory of gravity, we have taken scalar curvature as constant. Hence final result of gravitational collapse in this frame work is the existence of black hole and cosmological horizons, both of these form earlier than singularity. It has been shown that constant curvature term $f(R_{0})$ ($R_0$ is constant scalar curvature) slows down the collapsing process.Comment: 17 Pages, to appear in European Physical Journal

Opto-mechanical design of synchrotron radiation-based far-infrared spectroscopic ellipsometer with strong magnetic-field

The objective of this dissertation is to present opto-mechanical design of a synchrotron radiation based far-infrared spectroscopic ellipsometer with a strong external magnetic-field capability. Since high magnetic field has enabled major breakthrough in science such instrument will be highly important to the field of condensed matter physics and characterization of advanced electronic materials. This instrument will be installed at the multi-User facility with the most advanced synchrotron light source: Natonal Synchrotron Source (NSLS-II) at Brookhaven National Laboratory (BNL).The proposed here instrument is capable to measure full Mueller matrix spectroscopic ellipsometry spectra in high magnetic fields of up to 9 Tesla. The designed instrument consists of Polarization State Generator (PSG) chamber, Spectromag optical solenoid (high magnetic field up to 9 T), cryogenic sample stage, Polarization State Analyzer (PSA) chamber, and a bolometer. The PSG and PSA vacuum chambers are separated from the magnet volume with two pairs of gate valves equipped with optical windows. This instrument is capable of using synchrotron radiation in the spectral range of 20 cm-1 and 4000 cm-1. The sample stage could operate in the low temperature range down to 4 K with an option to cool sample down to 1.6 K. This instrument allows User to switch between Faraday and Voigt configurations for external magnetic field. This ellipsometer will be able to measure the full-Mueller matrix spectra using rotating retarders and rotating polarizers