Um ein in mikrobiologischer Hinsicht sicheres und gesundes Lebensmittel zu erhalten, sind während der Fleischgewinnung, von der landwirtschaftlichen Primärproduktion bis zur Schlachtstätte, hygienische Herstellungspraktiken erforderlich. Nachweislich wirken sich schmutzige Schlachtrinder entscheidend auf die Schlachthygiene aus. Die damit verbundene mikrobiologische Belastung des Schlachttierkörpers und die potenzielle Gefährdung für die Gesundheit der Verbraucher sind inakzeptabel. Verschmutzungen von Schlachtrindern entstehen in der Primärerzeugung, beim Transport sowie bei Anlieferung und Unterbringung der Tiere in der Schlachtstätte. Im Schlachtprozess bestehen Kontaminationsmöglichkeiten beim Betäuben, Entbluten, Vorenthäuten und beim Enthäuten. Dabei ist das Risiko der Verunreinigung im Schlachtprozess umso größer, je ausgeprägter die Verschmutzungen der lebenden Rinder bei der Anlieferung sind. Aufgabe der Schlachthygiene ist, diese Kontaminationen auf allen Stufen zu verhindern oder auf ein Mindestmaß zu beschränken. Mögliche Maßnahmen beginnen mit der Anlieferung der lebenden Tiere, die durch eine entsprechende Haltung und Fütterung oder durch vorheriges Reinigen oder Scheren, eine akzeptable Sauberkeit aufweisen. Verschmutzt angelieferte Tiere können in der Schlachtstätte gereinigt oder zurückgewiesen werden. Während des Schlachtprozesses können verschiedene verfahrenstechnische Maßnahmen, wie Zwischenreinigung der Anlage, separates Schlachten von verschmutzten Tieren, reduzierter Schlachtgeschwindigkeit oder Zurückheften des Fells beim maschinellen Enthäuten, die Schmutzübertragung verhindern. Kontaminationen, die durch diese Verfahren nicht verhindert werden, können nur noch im Nachhinein beseitigt werden mittels Wegschneiden von Verunreinigungen oder speziellen physikalischen, chemischen oder biologischen Dekontaminationsverfahren; diese haben aber entweder keine gesetzliche Zulassung oder werden aufgrund mangelnder Verbraucherakzeptanz nicht angewendet. Ziele Im Rahmen einer Literaturstudie wurden der Ursprung und die Auswirkungen von verschmutzten Schlachtrindern auf den Schlachtprozess untersucht. Anhand der Vorgaben des EU-Lebensmittelhygienerechts zur Fleischgewinnung wurden die Verantwortlichkeiten entlang der Produktionskette vom Primärerzeuger über den Schlachtstättenbetreiber und den amtlichen Tierarzt in der Schlachttier- und Fleischuntersuchung dargelegt. Maßnahmen müssen hier ansetzen, um den Eintrag von Kontaminationen auf einer frühen Stufe zu verhindern. Der amtliche Tierarzt nimmt hier eine zentrale Stellung ein. Auf der gesetzlichen Grundlage der VO (EG) Nr. 854/2004, in der als Kriterium zur Erteilung der Schlachterlaubnis gefordert wird, dass die Tiere sauber sein müssen, entscheidet er über die Zulassung der Tiere zur Schlachtung. Klare Ausführungen zur Verschmutzungseinschätzung fehlen hingegen. Die britische Clean-Livestock Policy (CLP) ist ein System zur Beurteilung der Tiersauberkeit. Sie beschreibt fünf eindeutige Verschmutzungsgrade in Wort und Bild und legt entsprechende Maßnahmen für die einzelnen Kategorien fest, die durch den Lebensmittelunternehmer an Schlachtstätten einzuleiten sind. Die CLP ist seit 1997 im englischen Fleischhygienerecht etabliert. Auch in anderen Mitgliedstaaten, wie Norwegen, Belgien, Niederlande oder Finnland, findet die Forderung nach sauberen Schlachttieren Berücksichtigung in nationalen Regelungen oder Leitlinien, die sich an Lebensmittelunternehmer oder Überwachungspersonal wenden. In Deutschland wurde die EU-rechtliche Forderung nach sauberen Schlachttieren bislang nicht durch nationale Regelungen ergänzt oder präzisiert. Material/Methode In eigenen Untersuchungen an 22.441 Schlachtrindern wurde das britische System der CLP auf Eignung im Rahmen der amtlichen Schlachttieruntersuchung getestet. Hierzu wurden Arbeitsanweisungen in Wort und Bild erstellt und die amtlichen Untersucher theoretisch und praktisch geschult. Die Befunde der Schlachttiere, die in die Verschmutzungskategorien 1-5 eingeteilt wurden, wurden statistisch ausgewertet und untersucht, welche Einflüsse auf die Tiersauberkeit im jahreszeitlichen Verlauf, im Vergleich der Untersuchungsjahre und Monate, sowie im Vergleich mit den englischen Untersuchungsbefunden zu erkennen waren. Ergebnisse Die eigenen Untersuchungen belegen, dass die Kategorisierung von Schlachttieren nach Verschmutzungsgraden einfach umzusetzen ist und einen geringen finanziellen und zeitlichen Aufwand bei größtmöglichem Nutzen mit sich bringt. Grenzfälle oder Schwierigkeiten bei der Beurteilung wurden erkannt. Die Umsetzung von Maßnahmen für Tiere mit starken Verschmutzungen hingegen ist noch nicht eindeutig gelöst. Die Ergebnisse der Verschmutzungsgrade zeigen, dass rund 50% der angelieferten Schlachttiere als „schmutzig“ eingeteilt wurden. Schlussfolgerung In der amtlichen Schlachttieruntersuchung könnte die Etablierung des CLP-Systems, mit einer eindeutigen Festlegung von Verschmutzungsgraden und den damit verbundenen Reglementierungen, eine signifikante Reduktion der Belastung der Schlachthygiene durch mittel- bis hochgradig verschmutzte Rinder ermöglichen.

O presente trabalho tratou do estudo dos riscos apresentados pelos radioisótopos após serem submetidos aos efeitos da detonação de um artefato explosivo. O estudo permitiu a obtenção de dados baseados em pesquisas bibliográficas, documentais, cálculos e softwares, possibilitando análises das consequências resultantes de artefatos explosivos contendo radioisótopos. O objetivo deste trabalho foi a obtenção de conhecimentos quanto à potencialidade destrutiva do explosivo denominado emulsão, composto principalmente por nitrato de amônia, bem como das propriedades do cobalto, iodo e do irídio que farão parte da carga destes explosivos. Supomos que à emulsão fossem acrescentadas as atividades de 1,5.102 TBq de cobalto-60, 3,7.10-3 TBq de iodo-131 e 3,7 TBq de irídio-192 que são suas atividades representativas em radioterapia, medicina nuclear e gamagrafia respectivamente. Avaliamos a progressão da pluma radioativa a partir do epicentro da explosão, possibilitando análises dos valores das doses, da distribuição e do alcance, a partir do epicentro, dos radioisótopos estudados. A simulação da progressão da pluma radioativa foi realizada por cálculos e simulação computacional fazendo uso dos programas Blast/FX Explosive Effects Analysis Software e The HotSpot Health Physics Codes - Version 2.07.2. No trabalho só foram estudadas as doses resultantes da exposição externa considerando que todo material radioativo volatizou. Foi deixado para estudos futuros calcular as doses internas e no pulmão bem como as doses resultantes de estilhaços radioativos produzidos na explosão. / This job devotes to the study of the radioisotopes risks, after the effects of an explosion of an explosive device. This study developes data based on bibliographies, documents, calculation and also software, and as a result, could provide analysis of an explosive device blast with radioisotopes. The purpose of this work is to provide knowlegde about the potencial destructive result of a blast of an explosive called emulsion, made with ammonia nitrate, and also with cobalt properties, iodine and iridium of a explosive charge. To this emulsion were added activities of 1,5.102 TBq of Cobalt-60, 3,7.10-3 TBq of iodine-131 and 3,7 TBq of iridium-192. Such activities are seen in radioterapy, nuclear medicine and gamagraphy. It could consider the radioative plume progress from the blast epicenter, in order to analyse the value of the dose, the distribution and the distance from the epicenter of the radioisotope studied. The simulation of the radioative plume progress was made with calculation and computer software, such as Blast/FX Explosive effects analysis software and The Hotspot health physics Codes version 2.07.2. In this study was only possible to check the doses from the external effects, to consider the fact that all radioative material result in volatization. It´s important to say that we left for future studies the calculation of the internal doses and inside the lung, and also the doses of the radioative shrapnel from the blast.

O presente trabalho tratou do estudo dos riscos apresentados pelos radioisótopos após serem submetidos aos efeitos da detonação de um artefato explosivo. O estudo permitiu a obtenção de dados baseados em pesquisas bibliográficas, documentais, cálculos e softwares, possibilitando análises das consequências resultantes de artefatos explosivos contendo radioisótopos. O objetivo deste trabalho foi a obtenção de conhecimentos quanto à potencialidade destrutiva do explosivo denominado emulsão, composto principalmente por nitrato de amônia, bem como das propriedades do cobalto, iodo e do irídio que farão parte da carga destes explosivos. Supomos que à emulsão fossem acrescentadas as atividades de 1,5.102 TBq de cobalto-60, 3,7.10-3 TBq de iodo-131 e 3,7 TBq de irídio-192 que são suas atividades representativas em radioterapia, medicina nuclear e gamagrafia respectivamente. Avaliamos a progressão da pluma radioativa a partir do epicentro da explosão, possibilitando análises dos valores das doses, da distribuição e do alcance, a partir do epicentro, dos radioisótopos estudados. A simulação da progressão da pluma radioativa foi realizada por cálculos e simulação computacional fazendo uso dos programas Blast/FX Explosive Effects Analysis Software e The HotSpot Health Physics Codes - Version 2.07.2. No trabalho só foram estudadas as doses resultantes da exposição externa considerando que todo material radioativo volatizou. Foi deixado para estudos futuros calcular as doses internas e no pulmão bem como as doses resultantes de estilhaços radioativos produzidos na explosão. / This job devotes to the study of the radioisotopes risks, after the effects of an explosion of an explosive device. This study developes data based on bibliographies, documents, calculation and also software, and as a result, could provide analysis of an explosive device blast with radioisotopes. The purpose of this work is to provide knowlegde about the potencial destructive result of a blast of an explosive called emulsion, made with ammonia nitrate, and also with cobalt properties, iodine and iridium of a explosive charge. To this emulsion were added activities of 1,5.102 TBq of Cobalt-60, 3,7.10-3 TBq of iodine-131 and 3,7 TBq of iridium-192. Such activities are seen in radioterapy, nuclear medicine and gamagraphy. It could consider the radioative plume progress from the blast epicenter, in order to analyse the value of the dose, the distribution and the distance from the epicenter of the radioisotope studied. The simulation of the radioative plume progress was made with calculation and computer software, such as Blast/FX Explosive effects analysis software and The Hotspot health physics Codes version 2.07.2. In this study was only possible to check the doses from the external effects, to consider the fact that all radioative material result in volatization. It´s important to say that we left for future studies the calculation of the internal doses and inside the lung, and also the doses of the radioative shrapnel from the blast.

O presente trabalho visa abordar as características do sistema político mexicano que permitiram o passo silencioso de um Estado com traços autoritários para um contrainsurgente. O sistema político mexicano, derivado da Revolução popular iniciada em 1910 e da criação do Partido Revolucionario Institucional(PRI), propiciou uma cultura política que fortaleceu a figura presidencial. Esta extrapolava as atribuições constitucionais e se legitimava tanto na política interna como na externa através do \"nacionalismo revolucionário\". Os governos de Gustavo Díaz Ordaz, Luis Echeverría e José López Portillo (1964-1982) estão marcados pela crise hegemônica evidenciada na radicalização das organizações de esquerda. Entre outros motivos, pelo esgotamento do modelo econômico desenvolvimentista, pela crise de representatividade do partido e falta de espaços para a participação política, pela corrupção das instituições e a escalada de violência do Estado contra a oposição. Nesses dezoito anos localizamos uma transformação nas formas de violência institucional pela assimilação da Doutrina de Segurança Nacional e a Doutrina Contrainsurgente dos Estados Unidos da América, por exemplo, na consolidação de grupos paramilitares pagos pelo Estado e treinados em norte-américa. O nacionalismo revolucionário possibilitou então que a submissão à ideologia estadunidense não fosse explícita, gerando dinâmicas repressivas (qualitativamente) similares às vivenciadas nas ditaduras latino-americanas. Ainda que o México tenha sido considerado uma democracia exemplar alheia às guerras sujas e aos golpes de Estado que comoveram o continente na segunda metade do século XX. O objetivo deste trabalho é salientar os elementos contraditórios existentes entre o discurso público, analisado a partir dos informes presidenciais, e o discurso elaborado desde os órgãos de segurança, isto é, os relatórios da Dirección Federal de Seguridad. Nessas contradições podemos ir avaliando as formas de alinhamento às doutrinas de segurança estrangeiras. / The main objective of this Master\'s project is to address the characteristics of the Mexican political system that allowed the silent step from a state with authoritarian traits to a counterinsurgent one. The Mexican political system, derived from the popular revolution that began in 1910 and from the creation of the Partido Revolucionario Institucional, maintained a political culture that strengthened the figure of president. This went beyond the powers permitted by the constitution and legitimized both internal and external policies through \"revolutionary nationalism.\" The governments of Gustavo Díaz Ordaz, Luis Echeverría, and José López Portillo (1964-1982) are marked by a hegemonic crisis seen in the radicalization of leftist organizations. Other motives for this shift include: the depletion of the developmentalist economic model, the crisis of representation in the party and a lack of spaces for political participation, the corruption of institutions, and the escalation of state violence against the opposition. In these eighteen years, a transformation occurs in the form of institutional violence through the assimilation of the National Security Doctrine of the United States; for example, the consolidation of paramilitary groups paid by the state and trained by northern neighbors. Revolutionary nationalism then allowed the non-explicit submission to American ideology, generating results (qualitatively) similar to those experienced in the repressive dynamics of Latin American dictatorships. Still, Mexico has been considered an exemplary democracy, despite dirty wars and coups that shocked the continent in the second half of the twentieth century.The aim of this study is to highlight the contradictory elements between the public discourse, analyzed from the presidential reports, and the discourse developed from the security organs, in other words, the reports of the Dirección Federal de Seguridad. These contradictions we can to evaluated the alignment of forms to foreign security doctrines.

O presente trabalho visa abordar as características do sistema político mexicano que permitiram o passo silencioso de um Estado com traços autoritários para um contrainsurgente. O sistema político mexicano, derivado da Revolução popular iniciada em 1910 e da criação do Partido Revolucionario Institucional(PRI), propiciou uma cultura política que fortaleceu a figura presidencial. Esta extrapolava as atribuições constitucionais e se legitimava tanto na política interna como na externa através do \"nacionalismo revolucionário\". Os governos de Gustavo Díaz Ordaz, Luis Echeverría e José López Portillo (1964-1982) estão marcados pela crise hegemônica evidenciada na radicalização das organizações de esquerda. Entre outros motivos, pelo esgotamento do modelo econômico desenvolvimentista, pela crise de representatividade do partido e falta de espaços para a participação política, pela corrupção das instituições e a escalada de violência do Estado contra a oposição. Nesses dezoito anos localizamos uma transformação nas formas de violência institucional pela assimilação da Doutrina de Segurança Nacional e a Doutrina Contrainsurgente dos Estados Unidos da América, por exemplo, na consolidação de grupos paramilitares pagos pelo Estado e treinados em norte-américa. O nacionalismo revolucionário possibilitou então que a submissão à ideologia estadunidense não fosse explícita, gerando dinâmicas repressivas (qualitativamente) similares às vivenciadas nas ditaduras latino-americanas. Ainda que o México tenha sido considerado uma democracia exemplar alheia às guerras sujas e aos golpes de Estado que comoveram o continente na segunda metade do século XX. O objetivo deste trabalho é salientar os elementos contraditórios existentes entre o discurso público, analisado a partir dos informes presidenciais, e o discurso elaborado desde os órgãos de segurança, isto é, os relatórios da Dirección Federal de Seguridad. Nessas contradições podemos ir avaliando as formas de alinhamento às doutrinas de segurança estrangeiras. / The main objective of this Master\'s project is to address the characteristics of the Mexican political system that allowed the silent step from a state with authoritarian traits to a counterinsurgent one. The Mexican political system, derived from the popular revolution that began in 1910 and from the creation of the Partido Revolucionario Institucional, maintained a political culture that strengthened the figure of president. This went beyond the powers permitted by the constitution and legitimized both internal and external policies through \"revolutionary nationalism.\" The governments of Gustavo Díaz Ordaz, Luis Echeverría, and José López Portillo (1964-1982) are marked by a hegemonic crisis seen in the radicalization of leftist organizations. Other motives for this shift include: the depletion of the developmentalist economic model, the crisis of representation in the party and a lack of spaces for political participation, the corruption of institutions, and the escalation of state violence against the opposition. In these eighteen years, a transformation occurs in the form of institutional violence through the assimilation of the National Security Doctrine of the United States; for example, the consolidation of paramilitary groups paid by the state and trained by northern neighbors. Revolutionary nationalism then allowed the non-explicit submission to American ideology, generating results (qualitatively) similar to those experienced in the repressive dynamics of Latin American dictatorships. Still, Mexico has been considered an exemplary democracy, despite dirty wars and coups that shocked the continent in the second half of the twentieth century.The aim of this study is to highlight the contradictory elements between the public discourse, analyzed from the presidential reports, and the discourse developed from the security organs, in other words, the reports of the Dirección Federal de Seguridad. These contradictions we can to evaluated the alignment of forms to foreign security doctrines.

Submitted by Maria Aparecida (cidazen@gmail.com) on 2017-04-07T14:18:39Z No. of bitstreams: 1 Bruna Feitosa Serra de Araujo.pdf: 1001875 bytes, checksum: c87401901bcc7e7a3491bcb77218f375 (MD5) / Made available in DSpace on 2017-04-07T14:18:39Z (GMT). No. of bitstreams: 1 Bruna Feitosa Serra de Araujo.pdf: 1001875 bytes, checksum: c87401901bcc7e7a3491bcb77218f375 (MD5) Previous issue date: 2017-03-22 / FAPEMA / The present research has as its scope the analysis of the Dirty List in the State of Maranhão as an action to repress slave labor. The historical context of neo-slavery and its normative repercussions are analyzed, through the recognition of the problem in the Inter-American Court of Human Rights and the regulatory framework at the international, national and state levels. Maranhão is present in the contemporary representation of slavery. It is observed that victimization for slave labor is linked to the cultural roots that for centuries tolerate this type of exploitation, together with impunity, lack of professional qualification and geographic isolation that favor this type of behavior in certain regions of the state. The (in) constitutionality of the Dirty List is considered in the light of the Federal Supreme Court, which in its decisions now prohibits, and authorizes its publication. / A presente pesquisa possui como escopo a análise da Lista Suja no Estado do Maranhão como ação de repressão do trabalho escravo. Analisa-se o contexto histórico da neo-escravidão e suas repercussões normativas, perpassando pelo reconhecimento do problema na Corte Interamericana de Direitos Humanos e o marco regulatório na esfera internacional, nacional e estadual. Verifica-se o Maranhão na representação contemporânea da escravatura. Observa-se que a vitimização para o trabalho escravo está ligada às raízes culturais que durante séculos toleram este tipo de exploração, somado à impunidade, à falta de qualificação profissional e ao isolamento geográfico que favorecem este tipo de conduta em determinadas regiões do estado. Aborda-se a (in)constitucionalidade da Lista Suja à luz do Supremo Tribunal Federal, que em suas decisões ora proíbe, ora autoriza sua publicação.

Submitted by Rosivalda Pereira (mrs.pereira@ufma.br) on 2017-05-16T17:02:02Z No. of bitstreams: 1 BrunaAraujo.pdf: 1002709 bytes, checksum: 2526e42a0c876e3f452631b63f9160c4 (MD5) / Made available in DSpace on 2017-05-16T17:02:02Z (GMT). No. of bitstreams: 1 BrunaAraujo.pdf: 1002709 bytes, checksum: 2526e42a0c876e3f452631b63f9160c4 (MD5) Previous issue date: 2017-03-22 / Fundação de Amparo à Pesquisa e ao Desenvolvimento Científico e Tecnológico do Maranhão (FAPEMA) / The present research has as its scope the analysis of the Dirty List in the State of Maranhão as an action to repress slave labor. The historical context of neo-slavery and its normative repercussions are analyzed, through the recognition of the problem in the Inter-American Court of Human Rights and the regulatory framework at the international, national and state levels. Maranhão is present in the contemporary representation of slavery. It is observed that victimization for slave labor is linked to the cultural roots that for centuries tolerate this type of exploitation, together with impunity, lack of professional qualification and geographic isolation that favor this type of behavior in certain regions of the state. The (in) constitutionality of the Dirty List is considered in the light of the Federal Supreme Court, which in its decisions now prohibits, and authorizes its publication. / A presente pesquisa possui como escopo a análise da Lista Suja no Estado do Maranhão como ação de repressão do trabalho escravo. Analisa-se o contexto histórico da neo-escravidão e suas repercussões normativas, perpassando pelo reconhecimento do problema na Corte Interamericana de Direitos Humanos e o marco regulatório na esfera internacional, nacional e estadual. Verifica-se o Maranhão na representação contemporânea da escravatura. Observa-se que a vitimização para o trabalho escravo está ligada às raízes culturais que durante séculos toleram este tipo de exploração, somado à impunidade, à falta de qualificação profissional e ao isolamento geográfico que favorecem este tipo de conduta em determinadas regiões do estado. Aborda-se a (in)constitucionalidade da Lista Suja à luz do Supremo Tribunal Federal, que em suas decisões ora proíbe, ora autoriza sua publicação.

This thesis discusses how certain societies (Germany, Israel, and Argentina) that have been involved in two documented cases of genocide in the 20th Century -- one that was the source for and falls within the United Nations Treaty definition of genocide (the Holocaust), and one that does not (the Dirty War in Argentina) --have dealt with these events in their recent past. In dealing with these issues, the thesis employs the analysis of genocide developed by the Argentine scholar, Daniel Feierstein, who has proposed that all genocides progress through a series of steps that first create what he calls a "negative otherness" to the victims of the genocide, that then isolates and debilitates the victim group, and that ultimately leads, as a penultimate (not final) step, to the physical annihilation of the victims of the genocide. Feierstein's most novel and provocative contribution to the study of genocide, however, is his concept that there is an additional and final step -- which he calls the threat of “symbolic realization” -- that will actually take place in society after the killing or physical annihilation has been completed and the historical order of things has been restored. In Feierstein’s view, the purpose of genocide is to use the technologies of power of the state against the victim group in order to permanently change social relations within the state by excluding and then annihilating the victims of the genocide. For this reason, Feierstein argues that, unless the post-genocide society continues to confront the causes and reality of the genocide as a present and ongoing political and social dynamic in the society, so that the memory and cultural and social presence of the victim group is preserved in an immediate way, the genocide will be realized on a symbolic level in the sense that the change of social relations that the perpetrators of the genocide intended will in fact occur. In the analysis that follows of the issues of assigning culpability, providing reparations, and constructing memorials in post-genocide societies, the thesis argues that, whether consciously articulated or not, what drives the bitter controversy and debates over these matters in post-genocide societies is an underlying fear on the part of victims and victim groups that the significance of what they have suffered and why they have suffered will be lost and forgotten (symbolically realized, in Feierstein’s terminology) in the state's efforts at reconciliation precisely through the process of assigning guilt, awarding reparations, and constructing memorials. Going a step beyond where Feierstein leaves off, the thesis suggests, however, that this sort of symbolic realization is, in fact, an inevitable and unavoidable consequence of the process of writing the history of the genocide (or any event) and the detachment, analysis, contextualization, reductiveness, and simplification that history requires.

Recent information theoretical results indicate that dirty-paper coding (DPC) achieves the entire capacity region of the Gaussian multiple-input multiple-output (MIMO) broadcast channel (BC). This thesis presents practical code designs for Gaussian BCs based on DPC. To simplify our designs, we assume constraints on the individual rates for each user instead of the customary constraint on transmitter power. The objective therefore is to minimize the transmitter power such that the practical decoders of all users are able to operate at the given rate constraints. The enabling element of our code designs is a practical DPC scheme based on nested turbo codes. We start with Cover's simplest two-user Gaussian BC as a toy example and present a code design that operates 1.44 dB away from the capacity region boundary at the transmission rate of 1 bit per sample per dimension for each user. Then we consider the case of the multiple-input multiple-output BC and develop a practical limit-approaching code design under the assumption that the channel state information is available perfectly at the receivers as well as at the transmitter. The optimal precoding strategy in this case can be derived by invoking duality between the MIMO BC and MIMO multiple access channel (MAC). However, this approach requires transformation of the optimal MAC covariances to their corresponding counterparts in the BC domain. To avoid these computationally complex transformations, we derive a closed-form expression for the optimal precoding matrix for the two-user case and use it to determine the optimal precoding strategy. For more than two users we propose a low-complexity suboptimal strategy, which, for three transmit antennas at the base station and three users (each with a single receive antenna), performs only 0.2 dB worse than the optimal scheme. Our obtained results are only 1.5 dB away from the capacity limit. Moreover simulations indicate that our practical DPC based scheme significantly outperforms the prevalent suboptimal strategies such as time division multiplexing and zero forcing beamforming. The drawback of DPC based designs is the requirement of channel state information at the transmitter. However, if the channel state information can be communicated back to the transmitter effectively, DPC does indeed have a promising future in code designs for MIMO BCs.

It remains unlikely that a terrorist organization could produce or procure an actual nuclear weapon. However, the construction of a radiological dispersal device (RDD) from commercially produced radioactive sources and conventional explosives could inflict moderate human casualties and significant economic damage. The vast availability of radioactive sources and the nearly limitless methods of dispersing them demand an inclusive study of the acquisition pathways for an RDD. A complete network depicting the possible acquisition pathways for an RDD could be subjected to predictive modeling in order to determine the most likely pathway an adversary might take. In this work, a comprehensive network of RDD acquisition pathways was developed and analyzed utilizing the Bayesian network analysis software, Netica. The network includes variable inputs and motivations that can be adjusted to model different adversaries. Also, the inclusion of evidence nodes facilitates the integration of real-time intelligence with RDD plot predictions. A sensitivity analysis was first performed to determine which nodes had the greatest impact on successful completion of RDD acquisition. These results detail which portions of the acquisition pathways are most vulnerable to law enforcement intervention. Next, a series of case studies was analyzed that modeled specific adversarial organizations. The analysis demonstrates various features of the constructed Bayesian RDD acquisition network and provides examples of how this tool can be utilized by intelligence analysts and law enforcement agencies. Finally, extreme cases were studied in which the adversary was given the maximum and minimum amount of resources in order to determine the limitations of this model. The aggregated results show that successful RDD acquisition is mostly dependent on the adversary’s resources. Furthermore, the network suggests that securing radiological materials has the greatest effect on interdicting possible RDD plots. Limitations of this work include a heavy dependence on conditional probabilities that were derived from intuition, as opposed to actual historical data which does not exist. However, the model can be updated as attempted or successful RDD plots emerge in the future. This work presents the first probabilistic model of RDD acquisition pathways that integrates adversary motivations and resources with evidence of specific RDD threats.