Pakistan Atomic Energy Commission Research Articles

Pakistan Reshuffles Weapons Program

Pakistan became the world’s seventh declared nuclear power in a showdown with India in 1998. Now, Pakistan has moved its nuclear weapons program out of the Pakistan Atomic Energy Commission (PAEC) and into the new National Defense Complex (NDC). The move separates the country’s unclassified and clandestine nuclear programs.At the same time, the government reassigned two top figures from the bomb program. Pervez Musharraf, the general who took over Pakistan in a bloodless coup two years ago, appointed Abdul Qadeer Khan, the father of Pakistan’s nuclear weapons program, and Ishfaq Ahmed, chairman of the PAEC, as his special science and technology advisers. The positions have the rank of a cabinet minister.Khan is frequently described as a national hero and is widely regarded as being an irreplaceable leader of Pakistan’s weapons program. He has headed the country’s premier uranium enrichment facility, the Khan Research Laboratories (KRL), since the 1970s, and has said he doesn’t want to leave. “Dr. Khan was very unhappy and complained publicly of being mistreated,” according to Pervez Hoodbhoy, a high-energy physicist at Quaid-I-Azam University in Islamabad. Hoodbhoy says he believes that the new appointments for Khan and Ahmed are compensation for being forced out of the nuclear bomb program. In an effort to dispel such rumors, General Musharraf gave a speech praising Khan shortly after the appointments were announced.Replacing Khan and Ahmed are two scientists who are relatively unknown outside of Pakistan. Javed Mirza, an experimental nuclear physicist who served as Khan’s deputy, is the new head of the KRL. And Pervez Butt, a nuclear engineer, has taken over as chairman of the PAEC, which now conducts only civilian research. The NDC, the new center for military research, is headed by Samar Mubarakmand, a nuclear scientist from PAEC who helped develop Pakistan’s medium-range ballistic missiles. He reports not to General Musharraf, but to the National Security Council, which oversees Pakistan’s nuclear weapons program. Mubarakmand insists publicly that no domestic or international interference in the program will be tolerated.Some analysts argue that the changes reflect a signal by Pakistan that it is willing to put its nuclear material under international safeguards and move closer to signing the Comprehensive Test Ban Treaty. Pakistan has been under intense pressure from the World Bank and the International Monetary Fund to reduce its military program. However, Uzair Haque, a representative of the government-run Pakistan Institute for Air Defense Studies, disputes this interpretation. “At first, the political opposition in Pakistan was under the impression that this was the beginning of a rollback of Pakistan’s nuclear program,” he says. “This is not the case.” Abdul Qadeer Khan (second from right) and other scientists from the Khan Research Laboratories stand in front of Ras Koh Hills nuclear test site moments after Pakistan’s 1998 nuclear tests.PAKISTAN INSTITUTE FOR AIR DEFENSE STUDIESPPT|High resolution© 2001 American Institute of Physics.

Dependence of radiation damage on deviation from the bragg angle

Abstract A sensitive method of detecting radiation damage in metals, by electron microscope observation of the shrinking of small, faulted, vacancy loops produced by prior quenching, has been used to study displacement damage in electron-irradiated aluminium. It has been shown that the difference in damage rate between specimens oriented for anomalous transmission and absorption is sufficiently small to be accounted for on the basis of present theories. We would like to thank Dr. A. Howie who suggested the experiment to us, Dr. M. S. Spring for making his calculations available to us in advance of publication and Dr. L. M. Brown for a number of very valuable discussions. One of us (K. A. S.) would like to thank the British Council for providing financial support and the Pakistan Atomic Energy Commission for granting leave of absence.

Ethylene Formation in Pea Epicotyl Tissues Following Irradiation with γ ‐Rays from 60Co

Physiologia PlantarumVolume 18, Issue 4 p. 1115-1120 Ethylene Formation in Pea Epicotyl Tissues Following Irradiation with γ -Rays from 60Co J. Shah, J. Shah Department of Pomology, University of California, Davis, California J. Shah's permanent address: Pakistan Atomic Energy Commission, P. O. Box 3112, Karachi.Search for more papers by this authorE. C. Maxie, E. C. Maxie Department of Pomology, University of California, Davis, CaliforniaSearch for more papers by this author J. Shah, J. Shah Department of Pomology, University of California, Davis, California J. Shah's permanent address: Pakistan Atomic Energy Commission, P. O. Box 3112, Karachi.Search for more papers by this authorE. C. Maxie, E. C. Maxie Department of Pomology, University of California, Davis, CaliforniaSearch for more papers by this author First published: October 1965 https://doi.org/10.1111/j.1399-3054.1965.tb07011.xCitations: 7 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume18, Issue4October 1965Pages 1115-1120 RelatedInformation

The Chromosomes of Hymenolepis microstoma (Dujardin 1845)

The chromosomes of Hymenolepis microstoma, studied in Feulgen-stained squash preparations of germ cells and early embryos, are 12 diploid. Their average size in first cleavage metaphase is 2 to 5 p. The inequality in size of some homologous chromosomes is explained in terms of origin from unequally contracted pronuclear chromosomes. Centromeres are terminal; heterochromatic regions exist near them. Meiosis in the oocytes and mitosis and cleavage in the early embryos are briefly described. Papers by Jones et al. (1945, 1951, 1956, 1957), Kisner (1961), and Douglas (1962) on the chromosomes of various cestodes have created interest in further cytological investigation of this group. Hymenolepis microstoma, the bile duct tapeworm of mice, became available in 1959 for laboratory use. The present study is part of a series of investigations into the biology of this worm (Dvorak et al., 1961). MATERIALS AND METHODS For the analysis of chromosomes, 20 normal worms belonging to a strain which has been maintained in our laboratory for the past 3 years were removed from two mice 14 days after infection and fixed in Carnoy's fixative (6:3:1 absolute alcoholchloroform-glacial acetic) for at least 12 hr. The specimens were then hydrated, hydrolyzed in water bath at 60 C in 1 N HCI for 12 min, rinsed in cold 1 N HC1, and stained in Feulgen's leukobasic fuchsin (prepared according to Gray, 1954) for at least 1 hr. The stained materials were preserved in distilled water in the refrigerator. Squash preparations were made of a small region of the anterior third of each worm using a drop of 45% acetic acid and sealing the cover glass with clear fingernail polish. The chromosomes of selected cells were drawn with the aid of an oil immersion objective (N.A. 1.40) and a camera lucida. Chromosomes from about 50 slides of normal oocytes and early embryos were studied. Since chromosomal details were observed best in oocytes and early embryos, the present study was largely confined to these stages. RESULTS Normal chromosome complements in somatic cells of the early embryo typically consist of 6 pairs, or 12 diploid. Of these, four pairs of homologues are of small size (2 to 3 4), one pair is of intermediate size (4 p), and one pair is definitely larger than the rest (5 4). The average size range, therefore, in first cleavage metaphase is 2 to 5 p. In some cells the two members of the largest pair are somewhat unequal in size (Fig. 10); in others, this difference in size cannot be clearly observed. The location of the centromere is not clearly visible in the metaphase chromosomes, but from the observations f early anaphase of first cleavage it is obvious t at all centromeres are terminal or very nearly so. Separation in early anaphase always begins at one end of the metaphase chromosomes. Also, in anaphase all chromosomes are rod-shaped (Fig. 8) as expected if centromeres are terminal. In some metaphase figures of first cleavage, there appear some lightly stained regions near one end of the chromosomes. These regions resemble subterminal centromeres, a suggestion which is not supported by studies of anaphase figures. The lightly stained portions should be considered heterochromatic regions extending from the terminal centromeres. Because the chromosomes of the testes are quite small, little was learned from testis material other than confirmation of the haploid number from meiotic metaphase in primary spermatocytes (Fig. 1). As the ovaries mature, they become lobed and packed with germ cells. The germ cells Received for publication 16 August 1962. * This study was supported in part by U. S. AEC contract AT(40-1) 1749. t On deputation from the Pakistan Atomic Energy Commission in a doctoral program sponsored by the U. S. Agency for International Development.