Neutrinos: Hunting Ghosts

Total Page:16

File Type:pdf, Size:1020Kb

Neutrinos: Hunting Ghosts Physics Neutrinos: Hunting ghosts This lesson is about neutrinos. In this lesson you will investigate the following: • Beta decay and the discovery of neutrinos • Neutrinos from the Sun • Neutrinos from space Find out how the ‘ghosts of matter’ may tell us the secrets of matter. This is a print version of an interactive online lesson. To sign up for the real thing or for curriculum details about the lesson go to www.cosmosforschools.com Neutrinos: Introduction This lesson is all about neutrinos – tiny ghostly particles much smaller than an atom. Billions of them have flewn through your body since you started reading this introduction. Most neutrinos come from space, travelling at the speed of light, and scientists are trying to find out more about them. To do so they have built an expensive neutrino detector deep in the ice near the South Pole. But before you read the article and look at the pictures, you will need to understand a few simple terms used there. The article talks about “subatomic particles”, which, as you might be able to guess, are the tiny particles that go together to make atoms. It also talks about “fusion”, this is the atomic reaction that happens when two atoms are joined, or fused, together. When they are, they release a lot of energy. The Sun and the stars give out light and heat energy because they are made up of billions of hydrogen atoms joining together to make helium. This is one way that neutrinos are formed, too. Another way neutrinos are created is when a large star explodes at the end of its life and becomes what we call a “supernova”. Now, go ahead and read the original Cosmos Magazine ​story to find out how the IceCube Neutrino Observatory is studying these elusive little particles. Read the full Cosmos Magazine article here​​ The neutrinos that we receive here on Earth come from the Sun and the deep reaches of space. Image credit: NASA Question 1 Interpret: The opening section of the Cosmos Magazine ​article is titled "Freezing a ghost". Why do you think the writer chose this catchy title? Question 2 Interpret: To help you understand the article, after reading each section try to think of another phrase for its heading. Cosmos heading Alternative heading Freezing a ghost Under the ice Captured Where in the Cosmos? Neutrinos: Gather Left to right: Lise Meitner, Wolfgang Pauli, Enrico Fermi & Wang Ganchang. Image credits: Getty Images & Wikipedia. Many people have contributed to our current understanding of neutrinos. Here is a little history of this tiny particle: 1911 Lise Meitner and Otto Hahn study beta decay and find evidence that the initial energy before decay is not accounted for by all of the decay products that they can detect. 1930 Wolfgang Pauli suggests that the missing energy is carried by a very small neutral particle. 1931 Enrico Fermi, an American born and brought up in Italy, names the particle "neutrino", Italian for "little neutral one". 1942 Wang Ganchang proposes a method for detecting the neutrino. 1956 Clyde Cowan and Frederick Raines detect the neutrino, receiving the Nobel Prize in 1995. Question 1 Imagine: The word "babyccino" describes a little capuccino. The word "neutrino" has its origins in Italian. Think up an English word to describe "a little neutral one". There may be students in your class from a non-English speaking background. You may wish to also ask them what word in their language could mean "a little neutral one". Symbols are used to represent elements. For example, C is the symbol for carbon and N is the symbol for nitrogen. The total number of particles in the nucleus, as well as the number of protons in the nucleus, can also be easily represented. For 14 example, a carbon atom with 14 particles in the nucleus, 6 of which are protons, can be written as 6C . Of course this means that there are 14 - 6 = 8 neutrons in the nucleus. Similarly there are symbols for the parts of atoms, including the neutrino. Particle Symbol 0 electron -1e proton p neutron n neutrino ν The symbol for the neutrino is ν, the Greek letter nu, which is the first syllable of neutrino. It is like the letter v but both lines are curved the same way. 14 14 0 A typical beta decay is 6C → 7N + -1e + ν Putting this into words it would read: A carbon nucleus decays into a nitrogen nucleus plus an electron and a neutrino. You will notice that the top numbers balance, i.e. 14 = 14 + 0, which means the total number of particles does not change. Also the bottom numbers balance 6 = 7 + -1, which means the total amount of charge does not change. These are called conservation rules. Question 2 40 40 0 ​​Calculate: Write the following decay in words: 19K → 20Ca + -1e + ν Question 3 Calculate: Find the unknown numbers, x and y, in each of the following: Equation x y 210 210 0 82Pb → xBi + -1e + ν N/A 234 x 0 yTh → 91Pa + -1e + ν Neutrinos are not only produced in beta decay but in nuclear events in the Sun, by supernovae and when matter falls into a black hole. In fact, billions of neutrinos are passing through your body every second, mainly from the Sun. This animated video looks at a neutrino called Nino that comes from the Sun and his travels from the Sun to the Earth, through the Earth and beyond. It is a six-minute cartoon with English subtitles, while the characters speak in Italian. Loading Nino Neutrino. Video credit: AGI / YouTube Question 4 Recount: Describe Nino's journey mentioning the different characters he meets on the way. Question 5 Describe: ​What happens to the protons and photons that Nino meets? Question 6 Calculate: The ​Cosmos Magazine article mentioned that 28 high energy neutrinos have been detected by the IceCube Neutrino Observatory. This was in the first two years of operation. Calculate the average time from detecting one neutrino to detecting the next. Question 7 Recall: ​In "Under the ice" the article refers to neutrinos hitting subatomic particles in hydrogen and oxygen nuclei. What subatomic particles exist in these nuclei? Question 8 Calculate: The section "Captured" mentions the light detectors. How many light detectors are there? If all the money (see opening section) had been spent on light detectors, how much would each have cost? ​ Neutrinos: Process Artist's impression of some of the IceCube Neutrino Observatory neutrino detectors. The section "Captured" also describes the detection of a very energetic neutrino. Its energy was measured at 1040.7 TeV. What is this unit of energy, eV, and what does the prefix, "T", stand for? You will have seen distances measured in kilometres, written as 50 km, the "k" means multiply by 1000 or 103, to give 50,000 metres. Similarly you may have heard about megahertz and gigabytes. "kilo", "mega" and "giga" are all multipliers. T stands for "Tera" and is another multiplier. Question 1 Infer: Complete the table below. Name Prefix Symbol Power Number Thousand Kilo k 103 1,000 Million Mega M 106 1,000,000 Billion (US) Giga G 109 1,000,000,000 Trillion Tera T 1012 Quadrillion Peta P 1,000,000,000,000,000 Googol N/A N/A 10100 Too long for this box! Question 2 15 ​Infer:​ The neutrino's energy is 1040.7 TeV, which is 1040.7 x 10 eV in power form. Write this value in number form with lots of zeroes. "eV" stands for electron volt. It is a unit of energy like Joules or kilowatt-hours, except that it is a very small value that is used when talking about electrons and protons. Where are these neutrinos coming from? After a neutrino impact, the amount of light that each detector receives can be used to work out the point in space from which the neutrino came. The oval image in the article (see Figure 3 below) is a map of the sky showing the part of the sky where each of the 28 detected neutrinos came from. But it looks very complicated. So, let us start with something familiar. Figure 1: The familiar map of the Earth. The flat map of the Earth is this peculiar shape because the Earth is a round ball but it is impossible to put the complete surface of a round ball on a sheet of paper, so this shape is a way of showing the curved surface of a sphere on a flat surface. The sky above us is also a bit like a round ball, so a similar map can be used. In the map of the sky in the ​Cosmos ​Magazine article (Figure 3, below), the line through the middle from left to right is the sky above the earth's equator. The top is the sky above the North pole and the bottom is the sky above the South pole. Figure 2 below is another map of the sky, this one showing the different constellations. Figure 2: A map of the night sky, also known as the atlas of the Universe. Image credit: Richard Powell Figure 3: A map showing where in the Universe the neutrinos detected by IceCube came from. Image credit: IceCube collaboration Question 3 Compare: In the map showing where the neutrinos came from (Figure 3) there is one area where many neutrinos seem to come from, that is, numbers 25, 24, 2, 14, etc. Look at the map of the constellations (Figure 2) and work out from which constellations these neutrinos came from.​ Careful! Figure 2 has the centre of our galaxy (marked 0°) at the centre of the map, where as Figure 3 has it on the far right.
Recommended publications
  • Joint Institute for Nuclear Research International Intergovernmental Organization
    Joint Institute for Nuclear Research International Intergovernmental Organization The Scienсe Policy of the Joint Institute for Nuclear Research .A issakianS Director I. JOINT INSTITUTE for NUCLEAR RESEARCH Albania Bulgaria China Czechoslovakia GDR Hungary D.P.R.Korea Mongolia Poland Romania USSR Vietnam The agreement on the establishment of JINR was signed on 26 March 1956 in Moscow 2006 European School on HEP 2 I. Founders V.Veksler I.Frank G.Flerov M.Meshcheryakov A.Baldin V.Dzhelepov N.Bogoliubov, D.Blokhintsev B.Pontecorvo H.Hulubei Wang Ganchang L.Infeld H.Niewodniczanski L.Janossy G.Najakov 3 I. 4 I. Governing Bodies & Structure Committee of Plenipotentiaries Scientific Council Directorate Finance Committee PAC for Particle Physics Science & Technology Council PAC for Nuclear Physics 7 Laboratories PAC for Condensed University Centre Matter Physics Office of Administration 2006 European School on HEP 5 J I. J JINR in figures I I N N R R JINR’s staff members ~ 5500 researchers ~ 1300 including from the Member States ~ 500 (but Russia) DD Doctors and PhD ~ 1000 uu bb nn a a 6 II. Scientific & Innovative Activities 7 II. JINR’s Science Policy Today and Tomorrow In 2006 the JINR Scientific Council approved the Road Map of the Institute’s strategic development for the next 10-15 years Special Economic Zone UC, DIAS-TH Technopark “Dubna” International Univ. ”Dubna” 8 II. The elaborated Road Map determined three major research directions at JINR: - high energy physics - nuclear physics - condensed matter physics Main Supporting Activities: Theory of PP, NP, CMP Networking and computing Physics methods Training of young staff 9 JINR’s research niche offered II.
    [Show full text]
  • The Interaction Between Scientists and Policy-Makers. Case Study of 863 Plan of China
    SISSA – International School for Advanced Studies Journal of Science Communication ISSN 1824 – 2049 http://jcom.sissa.it/ Comment BRIDGING THE GAP BETWEEN SCIENCE AND POLICY: THE IMPORTANCE OF MUTUAL RESPECT, TRUST AND THE ROLE OF MEDIATORS Exploring work: the interaction between scientists and policy-makers. Case study of 863 Plan of China Wen Ke ABSTRACT: Improving communications between scientists and policy makers have being received more and more attention in China. Based on negotiation-boundary work theory (Jasanoff, 1990), this paper presents an analysis of the interface between scientists and policy makers by drawing on the Strategic High-tech Research and Development Program of China (863 Program). The analysis indicates, first, that it is very important of science advice in China, the negotiation and the consensus between scientists and policy makers is vital for policy making; second, that it is dangerous to rely on Technocracy in China, the policy makers give up the discretion while influence experts’ decisions by controlling the consist of scientist advisory committee, which directly result in politicalizing academic research. For scientists and policy makers in China, they should redefine their respective authority boundary, and make the interaction process open and transparent. Introduction Today, as science and technology gradually become the driver for economic development and social impetus, they also have an impact on most core government functions,1 which resulted in the use of scientific consultations in policy-making. Therefore, interactions between scientists and policy-makers are getting more remarkable, especially in policy-making of public fields, like medicine, health, energy- saving, climate change, etc.2 Generally speaking, the interaction between scientists and policy makers to a large possibility depends on a country’s political context.3,4,5 Nations with dispersed and pluralistic power, such as US, have networking-style scientific consultations.
    [Show full text]
  • Neutrinos: a New Window to Our Universe Sabya Sachi Chatterjee [email protected] (Research Scholar at IOP)
    Neutrinos: A New Window to Our Universe Sabya Sachi Chatterjee [email protected] (Research scholar at IOP) Most abundant elementary particle in Nature Nuclear reactions in Sun and other massive Stars: a big • Neutrinos are everywhere source of extraterrestrial neutrinos • A key particle to understand our Universe Fig2. CNO cycle in massive Stars like Neutron Fig1. pp-chain reactions in Sun Star, White dwarf. Neutrino fluxes • Each second, 100 billion Solar Niels Bohr: Energy is not neutrinos passing through the tip of conserved in Quantum our finger ! domain. • Very weakly interacting particle; we do not see or feel them. Niels Bohr Mass of neutrino, mν ≈ 0:00001× mass of electron . The neutrino (name coined by Fermi) was postulated first by Detection of neutrinos Wolfgang Pauli in 1930 to explain how beta decay could Neutrinos are chargeless, difficult to detect. ? In 1942 Wang Ganchang first proposed the use of beta-capture to experimentally conserve energy, momentum, detect neutrinos. In 1956, the first experiment which confirmed the detection of + and angular momentum Wolfgang Pauli neutrino via the inverse beta decay (ν¯e + p ! n + e ) is known as Cowan–Reines (spin). neutrino experiment. Basic Properties of Neutrinos This result was rewarded with the Charge 0 1995 Nobel Prize to Frederick Mass ≈ 0 Reines. Spin 1/2 - Fermion Types (3: νe, νµ & ντ) Clyde Cowan conducting the neutrino experiment c. 1956. Family Lepton Neutrino Oscillation Interaction Weak • In the late 1960s, Ray Davis’s and John N. Bahcall’s Homestake Experiment was the first to measure the flux of neutrinos from the Sun and detected a deficit.
    [Show full text]
  • China's Strategic Modernization: Implications for the United States
    CHINA’S STRATEGIC MODERNIZATION: IMPLICATIONS FOR THE UNITED STATES Mark A. Stokes September 1999 ***** The views expressed in this report are those of the author and do not necessarily reflect the official policy or position of the Department of the Army, the Department of the Air Force, the Department of Defense, or the U.S. Government. This report is cleared for public release; distribution is unlimited. ***** Comments pertaining to this report are invited and should be forwarded to: Director, Strategic Studies Institute, U.S. Army War College, 122 Forbes Ave., Carlisle, PA 17013-5244. Copies of this report may be obtained from the Publications and Production Office by calling commercial (717) 245-4133, FAX (717) 245-3820, or via the Internet at [email protected] ***** Selected 1993, 1994, and all later Strategic Studies Institute (SSI) monographs are available on the SSI Homepage for electronic dissemination. SSI’s Homepage address is: http://carlisle-www.army. mil/usassi/welcome.htm ***** The Strategic Studies Institute publishes a monthly e-mail newsletter to update the national security community on the research of our analysts, recent and forthcoming publications, and upcoming conferences sponsored by the Institute. Each newsletter also provides a strategic commentary by one of our research analysts. If you are interested in receiving this newsletter, please let us know by e-mail at [email protected] or by calling (717) 245-3133. ISBN 1-58487-004-4 ii CONTENTS Foreword .......................................v 1. Introduction ...................................1 2. Foundations of Strategic Modernization ............5 3. China’s Quest for Information Dominance ......... 25 4.
    [Show full text]
  • China and Albert Einstein
    China and Albert Einstein China and Albert Einstein the reception of the physicist and his theory in china 1917–1979 Danian Hu harvard university press Cambridge, Massachusetts London, England 2005 Copyright © 2005 by the President and Fellows of Harvard College All rights reserved Printed in the United States of America Library of Congress Cataloging-in-Publication Data Hu, Danian, 1962– China and Albert Einstein : the reception of the physicist and his theory in China 1917–1979 / Danian Hu. p. cm. Includes bibliographical references and index. ISBN 0-674-01538-X (alk. paper) 1. Einstein, Albert, 1879–1955—Influence. 2. Einstein, Albert, 1879–1955—Travel—China. 3. Relativity (Physics) 4. China—History— May Fourth Movement, 1919. I. Title. QC16.E5H79 2005 530.11'0951—dc22 2004059690 To my mother and father and my wife Contents Acknowledgments ix Abbreviations xiii Prologue 1 1 Western Physics Comes to China 5 2 China Embraces the Theory of Relativity 47 3 Six Pioneers of Relativity 86 4 From Eminent Physicist to the “Poor Philosopher” 130 5 Einstein: A Hero Reborn from the Criticism 152 Epilogue 182 Notes 191 Index 247 Acknowledgments My interest in Albert Einstein began in 1979 when I was a student at Qinghua High School in Beijing. With the centennial anniversary of Einstein’s birth in that year, many commemorative publications ap- peared in China. One book, A Collection of Translated Papers in Com- memoration of Einstein, in particular deeply impressed me and kindled in me a passion to understand Einstein’s life and works. One of the two editors of the book was Professor Xu Liangying, with whom I had the good fortune of studying while a graduate student.
    [Show full text]
  • Tracing the History of Radiobiology in Twentieth-Century China Author(S)
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by HKU Scholars Hub Radium, Biophysics, and Radiobiology: Tracing the History of Title Radiobiology in Twentieth-Century China Author(s) Luk, YLC History and Philosophy of the Life Sciences, 2018, v. 40 n. 1, Citation article 2 Issued Date 2018 URL http://hdl.handle.net/10722/243629 The final publication is available at Springer via http://dx.doi.org/10.1007/s40656-017-0169-7; This work is Rights licensed under a Creative Commons Attribution- NonCommercial-NoDerivatives 4.0 International License. Page containing authors contact details TITLE PAGE Name of the author: Christine Yi Lai Luk Title: Radium, biophysics, and radiobiology: tracing the history of radiobiology in twentieth-century China Affiliation: the University of Hong Kong Address: Hong Kong Institute for the Humanities and Social Sciences, the University of Hong Kong, Pokfulam Road, Hong Kong Abstract: Radiobiology assesses the biological hazards of exposure to radioactive substances and nuclear radiation. This article explores the history of radiobiology in twentieth-century China by examining the overlapping of radium research and biophysics, from roughly the 1920s Nationalist period to the 1960s Communist period; from the foreign purchase of radium by the Rockefeller Foundation’s China Medical Board during the Republican era, to the institutional establishment of radiobiology as a subset of biophysics in the People’s Republic. Western historiography of radiobiology highlights the connection between the military development of nuclear weapons and the civilian use of radiation in biology, as well as the international export of radioisotopes and nuclear reactors.
    [Show full text]
  • Physics and Politics
    Beitriige zur Geschichte der Deutschen Forschungsgemeinschaft - I Franz Steiner Verlag Sonderdrucl< aus: Physics and Politics Research and Research Support in TWentieth Century Germany in International Perspective Edited by Helmuth Trischler and Mark Walker j @ Franz Steiner vertag 2o1o t :'i PHYSICS IN CHINA IN THE CONTEXT OF THE coLD \rAR. 1949-1976 Zuo-yue Wang In April 1952, just days after he was appointed the associate director of the In- stitute of Modern Physics of the Chinese Academy of Sciences in Beijing, the Chinese nuclear physicist Wang Ganchang was called into the headquarters of the academy. A secret mission awaited him at the battle front of the Korean \Var: The Chinese forces suspected the US had used "atomic sheils" and wanted W'ang to investigate the matter. \fang, a physicist who had gone to Berlin University to study with Hans Geiger but ended up receiving his Ph. D. with Lise Meitner at the Kaiser \Tilhelm Institute in 1933, was well-qualified for the job. With a primi- tive but effective Geiger counter, W'ang checked fragments of the suspect shells and found that there was no increase in radioactivity. He concluded that they were not mini atomic bombs, but perhaps a new type of conventional weapon.l A relatively minor incident in the Korean W'ar, it nevertheless marked a milestone toward the be ginning of an era when the Cold War and nuclear weapons increas- ingly and decisively shaped the context within which physics was practiced in the People's Republic of China under Mao Zedong. A decade later, \fang emerged as a major architect of the Chinese nuclear weapons project and his whole institute and most of the leading Chinese physicists devoted themselves to it.
    [Show full text]
  • Nova Brekhnia Zamist Staroi.Pdf
    Анатолій Ґоліцин Нова брехня замість старої Комуністична стратегія облуди та дезінформації 2020 Переклад на українську: “New Lies for Old: The Communist Strategy of Deception and Disinformation” Anatoliy Golitsyn, Dodd, Mead & Company, N.Y., 1984 Неофіційний переклад. Зворотний зв’язок: [email protected] Редакція 1 Червень 2020 Зміст Передмова редакторів ........................................vii Передмова автора .............................................xi Частина I Дві методології .........................1 Глава 1. Проблеми, що чекають на західних аналітиків . 2 Загальні труднощі — 2. Особливі труднощі: дезінформація — 3. Дезінформація в комуністичних режимах — 4 Глава 2. Модель дезінформації: “слабкість та еволюція” . 9 Модель “слабкість та еволюція” — 9. Прецедент НЕПу — 10. Результати НЕПу — 15. Урок НЕПу — 16 Глава 3. Модель дезінформації: “фасад і міць” . 17 Офіційні виступи та партійні документи — 19. Спеціальні дезінформаційні операції — 20 Глава 4. Модель дезінформації: “перехід” ...................22 Оманлива десталінізація — 23. Антикомунізм — 24. Антисталінізм — 25. Десталінізація на практиці — 28. Імпровізована десталінізація з 1953 по 1956 рік — 28. Ресталінізація — 30 Глава 5. Нова політика і стратегія дезінформації . 32 Нова політика — 33. Недоліки явної єдності — 35. Переваги явної відокремленості — 36. Політичне використання десталінізації — 37. Джерела натхнення — 40 i Глава 6. Доповідь Шелєпіна та зміни в організації . 45 Відділ Д — 49 Глава 7. Нова роль спецслужб ...............................51 Глава 8.
    [Show full text]
  • Who's Behind China's High-Technology “Revolution”?
    Who’s Behind China’s Evan A. Feigenbaum High-Technology “Revolution”? How Bomb Makers Remade Beijing’s Priorities, Policies, and Institutions For seven years after the Tiananmen Square tragedy of 1989, virtually all signiªcant issues in U.S.- China relations became subordinate to concern about human rights and China’s suppression of political dissent. Yet in the three years since China’s 1996 missile exercise in the Taiwan Strait, high-technology issues have come increasingly to replace human rights at the center of the contentious and often politicized discussion that characterizes current debate about U.S.-China policy. Recent allegations concerning satellite exports and nuclear espionage, in particular, demonstrate the centrality of high technology to the debate about China’s place in the world. This makes it especially important to explore links that may bind China’s national technology and industrial policies to its ap- proach to security and development. How has the Chinese understanding of this linkage changed as the past priority of militarized growth has given way to the rapid expansion of a commercial economy since the late 1970s?1 Who is responsible for making important technology decisions in China? How have Chinese technology leaders thought about the relationship between technology and national power during the past twenty years? Has political change affected this worldview? Finally, how has renewed contact with international technical circles since the 1970s affected the Chinese approach to national high-tech strategy and investment? Evan A. Feigenbaum is a Fellow at the Belfer Center for Science and International Affairs at Harvard University’s John F.
    [Show full text]
  • Advanced Technology Acquisition Strategies of the People's Republic
    Advanced Technology Acquisition Strategies of the People’s Republic of China Principal Author Dallas Boyd Science Applications International Corporation Contributing Authors Jeffrey G. Lewis and Joshua H. Pollack Science Applications International Corporation September 2010 This report is the product of a collaboration between the Defense Threat Reduction Agency’s Advanced Systems and Concepts Office and Science Applications International Corporation. The views expressed herein are those of the authors and do not necessarily reflect the official policy or position of the Defense Threat Reduction Agency, the Department of Defense, or the United States Government. This report is approved for public release; distribution is unlimited. Defense Threat Reduction Agency Advanced Systems and Concepts Office Report Number ASCO 2010-021 Contract Number DTRA01-03-D-0017, T.I. 18-09-03 The mission of the Defense Threat Reduction Agency (DTRA) is to safeguard America and its allies from weapons of mass destruction (chemical, biological, radiological, nuclear, and high explosives) by providing capabilities to reduce, eliminate, counter the threat, and mitigate its effects. The Advanced Systems and Concepts Office (ASCO) supports this mission by providing long-term rolling horizon perspectives to help DTRA leadership identify, plan, and persuasively communicate what is needed in the near-term to achieve the longer-term goals inherent in the Agency’s mission. ASCO also emphasizes the identification, integration, and further development of leading strategic thinking and analysis on the most intractable problems related to combating weapons of mass destruction. For further information on this project, or on ASCO’s broader research program, please contact: Defense Threat Reduction Agency Advanced Systems and Concepts Office 8725 John J.
    [Show full text]
  • China Keeping the Lid on Demands for Change
    June 1995 Vol. 7, No. 7 CHINA KEEPING THE LID ON DEMANDS FOR CHANGE One year after President Clinton unconditionally renewed Most Favored Nation status for China and international pressure on China to improve its human rights practices dropped off dramatically, the Chinese government continues to impose tight controls on dissent and to engage in a pattern of systematic abuse of prisoners. More than a dozen well-known intellectuals have been detained since mid-May in response to petitions they signed seeking greater political openness. They include former political prisoner and literary critic Liu Xiaobo, student leader Wang Dan, and labor activist Liu Nianchun. Dozens of other dissidents have been called in for questioning as the sixth anniversary of the 1989 Tiananmen Square crackdown approaches. Wei Jingsheng, China's most famous political prisoner, remains in government custody in an unknown location, and other well-known prisoners have "disappeared." Tight new security laws have been put into effect. Torture continues in China's vast network of prisons, detention centers and labor camps, as does the production by prisoners of goods for export. Freedom of expression and association remain tightly restricted, and the government seems determined to ensure that the controls placed on Chinese citizens will be extended to the tens of thousands of foreign non-governmental organization (NGO) activists planning to take part in the United Nations Fourth World Conference on Women to be held in Beijing in September 1995. In this report Human Rights Watch calls on the world's industrialized countries, meeting in mid-June in Halifax, Nova Scotia for a G-7 summit, to develop a common strategy for addressing this pattern of systematic abuse.
    [Show full text]
  • Academic Adjustment of Chinese Students at German Universities
    Academic Adjustment of Chinese Students at German Universities Dissertation zur Erlangung des akademischen Grades Dr. phil. im Fach Erziehungswissenschaften eingereicht am 16. August 2012 an der Philosophischen Fakultät IV der Humboldt-Universität zu Berlin von Jiani Zhu Master of Education Prof. Dr. Jan-Hendrik Olbertz Präsident der Humboldt-Universität zu Berlin Prof. Dr. Dr. h. c. Jürgen van Buer Dekan der Philosophischen Fakultät IV Gutachter: 1. Prof. Dr. Jürgen Henze 2. Prof. Dr. Andrä Wolter Tag der Verteidigung: 21.11.2012 ii Acknowledgements I still remembered clearly how excited I was when I first visited the Humboldt- Universität, the “mother of all modern universities” in 2007. In the last four years, I spent the most productive, meaningful, and important time at the Humboldt-Universität. I owe a lot to many people, without whom this dissertation would not have been possible. First and foremost I am profoundly grateful to my supervisor, Professor Jürgen Henze, who appeared to me as the true embodiment of a mentor. Without his skilful guidance and expertise in the field of intercultural communication, this dissertation would not have been possible. In German language, doctoral advisors are called Doktorvater (literally “doctor-father”). Professor Henze acts exactly as my “academic father”, who leads me to explore the academic world. I appreciate his contributions of time and ideas to make my research experience productive and stimulating. I am thankful for the excellent example he has provided as a diligent and meticulous scholar. For this dissertation, I would like to thank the review committee members. I am grateful to Professor Andrä Wolter for being my reviewer.
    [Show full text]