Comprehensive Nuclear Test-Ban Treaty.

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Sviluppo di metodologie di localizzazione nel contesto del Comprehensive Nuclear Test-Ban Treaty

Since the first underground nuclear explosion, carried out in 1958, the analysis of seismic signals generated by these sources has allowed seismologists to refine the travel times of seismic waves through the Earth and to verify the accuracy of the location algorithms (the ground truth for these sources was often known). Long international negotiates have been devoted to limit the proliferation and testing of nuclear weapons. In particular the Treaty for the comprehensive nuclear test ban (CTBT), was opened to signatures in 1996, though, even if it has been signed by 178 States, has not yet entered into force, The Treaty underlines the fundamental role of the seismological observations to verify its compliance, by detecting and locating seismic events, and identifying the nature of their sources. A precise definition of the hypocentral parameters represents the first step to discriminate whether a given seismic event is natural or not. In case that a specific event is retained suspicious by the majority of the State Parties, the Treaty contains provisions for conducting an on-site inspection (OSI) in the area surrounding the epicenter of the event, located through the International Monitoring System (IMS) of the CTBT Organization. An OSI is supposed to include the use of passive seismic techniques in the area of the suspected clandestine underground nuclear test. In fact, high quality seismological systems are thought to be capable to detect and locate very weak aftershocks triggered by underground nuclear explosions in the first days or weeks following the test. This PhD thesis deals with the development of two different seismic location techniques: the first one, known as the double difference joint hypocenter determination (DDJHD) technique, is aimed at locating closely spaced events at a global scale. The locations obtained by this method are characterized by a high relative accuracy, although the absolute location of the whole cluster remains uncertain. We eliminate this problem introducing a priori information: the known location of a selected event. The second technique concerns the reliable estimates of back azimuth and apparent velocity of seismic waves from local events of very low magnitude recorded by a trypartite array at a very local scale. For the two above-mentioned techniques, we have used the crosscorrelation technique among digital waveforms in order to minimize the errors linked with incorrect phase picking. The cross-correlation method relies on the similarity between waveforms of a pair of events at the same station, at the global scale, and on the similarity between waveforms of the same event at two different sensors of the try-partite array, at the local scale. After preliminary tests on the reliability of our location techniques based on simulations, we have applied both methodologies to real seismic events. The DDJHD technique has been applied to a seismic sequence occurred in the Turkey-Iran border region, using the data recorded by the IMS. At the beginning, the algorithm was applied to the differences among the original arrival times of the P phases, so the cross-correlation was not used. We have obtained that the relevant geometrical spreading, noticeable in the standard locations (namely the locations produced by the analysts of the International Data Center (IDC) of the CTBT Organization, assumed as our reference), has been considerably reduced by the application of our technique. This is what we expected, since the methodology has been applied to a sequence of events for which we can suppose a real closeness among the hypocenters, belonging to the same seismic structure. Our results point out the main advantage of this methodology: the systematic errors affecting the arrival times have been removed or at least reduced. The introduction of the cross-correlation has not brought evident improvements to our results: the two sets of locations (without and with the application of the cross-correlation technique) are very similar to each other. This can be commented saying that the use of the crosscorrelation has not substantially improved the precision of the manual pickings. Probably the pickings reported by the IDC are good enough to make the random picking error less important than the systematic error on travel times. As a further justification for the scarce quality of the results given by the cross-correlation, it should be remarked that the events included in our data set don’t have generally a good signal to noise ratio (SNR): the selected sequence is composed of weak events ( magnitude 4 or smaller) and the signals are strongly attenuated because of the large distance between the stations and the hypocentral area. In the local scale, in addition to the cross-correlation, we have performed a signal interpolation in order to improve the time resolution. The algorithm so developed has been applied to the data collected during an experiment carried out in Israel between 1998 and 1999. The results pointed out the following relevant conclusions: a) it is necessary to correlate waveform segments corresponding to the same seismic phases; b) it is not essential to select the exact first arrivals; and c) relevant information can be also obtained from the maximum amplitude wavelet of the waveforms (particularly in bad SNR conditions). Another remarkable point of our procedure is that its application doesn’t demand a long time to process the data, and therefore the user can immediately check the results. During a field survey, such feature will make possible a quasi real-time check allowing the immediate optimization of the array geometry, if so suggested by the results at an early stage.

The consequences of a comprehensive test ban treaty [microform] : report /

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Alteration of natural ³⁷Ar activity concentration in the subsurface by gas transport and water infiltration

High ³⁷Ar activity concentration in soil gas is proposed as a key evidence for the detection of underground nuclear explosion by the Comprehensive Nuclear Test-Ban Treaty. However, such a detection is challenged by the natural background of ³⁷Ar in the subsurface, mainly due to Ca activation by cosmic rays. A better understanding and improved capability to predict ³⁷Ar activity concentration in the subsurface and its spatial and temporal variability is thus required. A numerical model integrating ³⁷Ar production and transport in the subsurface is developed, including variable soil water content and water infiltration at the surface. A parameterized equation for ³⁷Ar production in the first 15 m below the surface is studied, taking into account the major production reactions and the moderation effect of soil water content. Using sensitivity analysis and uncertainty quantification, a realistic and comprehensive probability distribution of natural ³⁷Ar activity concentrations in soil gas is proposed, including the effects of water infiltration. Site location and soil composition are identified as the parameters allowing for a most effective reduction of the possible range of ³⁷Ar activity concentrations. The influence of soil water content on ³⁷Ar production is shown to be negligible to first order, while ³⁷Ar activity concentration in soil gas and its temporal variability appear to be strongly influenced by transient water infiltration events. These results will be used as a basis for practical CTBTO concepts of operation during an OSI.

Contamination of Alpine snow and ice at Colle Gnifetti, Swiss/Italian Alps, from nuclear weapons tests

Plutonium is present in the environment as a consequence of atmospheric nuclear tests, nuclear weapons production and industrial releases over the past 50 years. To study temporal trends, a high resolution Pu record was obtained by analyzing 52 discrete samples of an alpine firn/ice core from Colle Gnifetti (Monte Rosa, 4450 m a.s.l.), dating from 1945 to 1990. The 239Pu signal was recorded directly, without decontamination or preconcentration steps, using an Inductively Coupled Plasma - Sector Field Mass Spectrometer (ICP-SFMS) equipped with an high efficiency sample introduction system, thus requiring much less sample preparation than previously reported methods. The 239Pu profile reflects the three main periods of atmospheric nuclear weapons testing: the earliest peak lasted from 1954/55 to 1958 and was caused by the first testing period reaching a maximum in 1958. Despite a temporary halt of testing in 1959/60, the Pu concentration decreased only by half with respect to the 1958 peak due to long atmospheric residence times. In 1961/62 Pu concentrations rapidly increased reaching a maximum in 1963, which was about 40% more intense than the 1958 peak. After the signing of the "Limited Test Ban Treaty" between USA and USSR in 1964, Pu deposition decreased very sharply reaching a minimum in 1967. The third period (1967-1975) is characterized by irregular Pu concentrations with smaller peaks (about 20-30% of the 1964 peak) which might be related to the deposition of Saharan dust contaminated by the French nuclear tests of the 1960s. The data presented are in very good agreement with Pu profiles previously obtained from the Col du Dome ice core (by multi-collector ICP-MS) and Belukha ice core (by Accelerator Mass Spectrometry, AMS). Although a semi-quantitative method was employed here, the results are quantitatively comparable to previously published results.

La Pace Calda. La nascita del movimento antinucleare negli Stati Uniti e in Gran Bretagna, 1957-1963

The aim of this proposal is to offer an alternative perspective on the study of Cold War, since insufficient attention is usually paid to those organizations that mobilized against the development and proliferation of nuclear weapons. The antinuclear movement began to mobilize between the 1950s and the 1960s, when it finally gained the attention of public opinion, and helped to build a sort of global conscience about nuclear bombs. This was due to the activism of a significant part of the international scientific community, which offered powerful intellectual and political legitimization to the struggle, and to the combined actions of the scientific and organized protests. This antinuclear conscience is something we usually tend to consider as a fait accompli in contemporary world, but the question is to show its roots, and the way it influenced statesmen and political choices during the period of nuclear confrontation of the early Cold War. To understand what this conscience could be and how it should be defined, we have to look at the very meaning of the nuclear weapons that has deeply modified the sense of war. Nuclear weapons seemed to be able to destroy human beings everywhere with no realistic forms of control of the damages they could set off, and they represented the last resource in the wide range of means of mass destruction. Even if we tend to consider this idea fully rational and incontrovertible, it was not immediately born with the birth of nuclear weapons themselves. Or, better, not everyone in the world did immediately share it. Due to the particular climate of Cold War confrontation, deeply influenced by the persistence of realistic paradigms in international relations, British and U.S. governments looked at nuclear weapons simply as «a bullet». From the Trinity Test to the signature of the Limited Test Ban Treaty in 1963, many things happened that helped to shift this view upon nuclear weapons. First of all, more than ten years of scientific protests provided a more concerned knowledge about consequences of nuclear tests and about the use of nuclear weapons. Many scientists devoted their social activities to inform public opinion and policy-makers about the real significance of the power of the atom and the related danger for human beings. Secondly, some public figures, as physicists, philosophers, biologists, chemists, and so on, appealed directly to the human community to «leave the folly and face reality», publicly sponsoring the antinuclear conscience. Then, several organizations leaded by political, religious or radical individuals gave to this protests a formal structure. The Campaign for Nuclear Disarmament in Great Britain, as well as the National Committee for a Sane Nuclear Policy in the U.S., represented the voice of the masses against the attempts of governments to present nuclear arsenals as a fundamental part of the international equilibrium. Therefore, the antinuclear conscience could be defined as an opposite feeling to the development and the use of nuclear weapons, able to create a political issue oriented to the influence of military and foreign policies. Only taking into consideration the strength of this pressure, it seems possible to understand not only the beginning of nuclear negotiations, but also the reasons that permitted Cold War to remain cold.

The effect of a reform on a school organizational culture after receiving a failing Florida Comprehensive Assessment Test rating

The purpose of this research was to explore the effects of a reform that took place in an elementary school during 2000/2001 as a result of a failure rating on the Florida Comprehensive Assessment Test on the structure and the personnel of the organization. ^ The exploration took place over a period of 10 months starting in August 2000 until June 2001. It focused on the effect of the failure rating on the: (a) structure and operation of the school; (b) morale, beliefs, behaviors, and daily lives of teachers and the principal; and (c) the effect of the reform effort on the leadership style of the principal, whether she became a transactional or a transformative leader. ^ The researcher assumed the role of a participant observer. Data sources were her personal recollections of major events that took place during the year of the reform, interviews, observations, and school documents. The sample included 15 teachers present during the time of the reform. Ten taught second through fifth grade. The remaining five participants were the music teacher, the counselor, and the writing, reading and technology specialists. Together they represented the instructional team or represented special education areas. ^ The findings indicated that the reform effort had an effect on the structure and the operation of the school. The changes included reorganization of the physical set up, changes in curriculum and instruction, changes in the means of communication among the staff, and the addition of new staff members including an official agent of change. The reform had a greater effect on the daily lives of teachers and their morale than on their beliefs and behaviors. Teachers reported that during the effort their daily lives were stressful and their morale very low due to the enormous expectations that they had to meet. On the other hand, the reform effort had a positive effect on the daily life, morale, beliefs, and behaviors of the principal. It energized her. She spoke positively about the change. She functioned as an effective, positive, resilient transactional leader who did what was necessary in order to enable the teachers to cope with the complex situation. ^

High Stakes and No Takers: The Impact of Florida Comprehensive Assessment Test (FCAT) Writing on Students’ and Teachers’ Perceptions of Writing

This ethnographic case study of ten students and their teachers concludes that the state writing test had a negative impact on students’ and teachers’ perceptions of writing in four categories: strengths and weaknesses in student writing, self-assessment of writing skills, factors impacting test scores, and motivation and attitudes toward writing.

The effect of a reform on a school organizational culture after receiving a failing Florida Comprehensive Assessment Test rating

The purpose of this research was to explore the effects of a reform that took place in an elementary school during 2000/2001 as a result of a failure rating on the Florida Comprehensive Assessment Test on the structure and the personnel of the organization. The exploration took place over a period of 10 months starting in August 2000 until June 2001. It focused on the effect of the failure rating on the: (a) structure and operation of the school; (b) morale, beliefs, behaviors, and daily lives of teachers and the principal; and (c) the effect of the reform effort on the leadership style of the principal, whether she became a transactional or a transformative leader. The researcher assumed the role of a participant observer. Data sources were her personal recollections of major events that took place during the year of the reform, interviews, observations, and school documents. The sample included 15 teachers present during the time of the reform. Ten taught second through fifth grade. The remaining five participants were the music teacher, the counselor, and the writing, reading and technology specialists. Together they represented the instructional team or represented special education areas. The findings indicated that the reform effort had an effect on the structure and the operation of the school. The changes included reorganization of the physical set up, changes in curriculum and instruction, changes in the means of communication among the staff, and the addition of new staff members including an official agent of change. The reform had a greater effect on the daily lives of teachers and their morale than on their beliefs and behaviors. Teachers reported that during the effort their daily lives were stressful and their morale very low due to the enormous expectations that they had to meet. On the other hand, the reform effort had a positive effect on the daily life, morale, beliefs, and behaviors of the principal. It energized her. She spoke positively about the change. She functioned as an effective, positive, resilient transactional leader who did what was necessary in order to enable the teachers to cope with the complex situation.

Statement submitted by the United States of Brazil to the President of the United States of America as arbitrator : under the provisions of the treaty concluded september 7, 1889, between Brazil and the Argentine Republic

Exposição que os Estados Unidos do Brazil apresentam ao Presidente dos Estados Unidos da América como árbitro seguindo as estipulações no Tratado de 7 de setembro de 1889, concluído entre o Brazil e a Republica Argentina.