Security and reliability of LPDC based public-key cryptosystems

Security and reliability of LDPC based public-key cryptosystems are discussed and analysed. We study attacks on the cryptosystem when partial knowledge of one or more of the private key components and/or of the plaintext have been acquired.

Cleavage of caspases-1, -3, -6, -8 and -9 substrates by proteases in skeletal muscles from mice undergoing cancer cachexia

A prominent feature of several type of cancer is cachexia. This syndrome causes a marked loss of lean body mass and muscle wasting, and appears to be mediated by cytokines and tumour products. There are several proteases and proteolytic pathways that could be responsible for the protein breakdown. In the present study, we investigated whether caspases are involved in the proteolytic process of skeletal muscle catabolism observed in a murine model of cancer cachexia (MAC16), in comparison with a related tumour (MAC13), which does not induce cachexia. Using specific peptide substrates, there was an increase of 54% in the proteolytic activity of caspase-1, 84% of caspase-8, 98% of caspase-3 151% to caspase-6 and 177% of caspase-9, in the gastrocnemius muscle of animals bearing the MAC16 tumour (up to 25% weight loss), in relation to muscle from animals bearing the MAC13 tumour (1-5% weight loss). The dual pattern of 89 kDa and 25 kDa fragmentation of poly (ADP-ribose) polymerase (PARP) occurred in the muscle samples from animals bearing the MAC16 tumour and with a high amount of caspase-like activity. Cytochrome c was present in the cytosolic fractions of gastrocnemius muscles from both groups of animals, suggesting that cytochrome c release from mitochondria may be involved in caspase activation. There was no evidence for DNA fragmentation into a nucleosomal ladder typical of apoptosis in the muscles of either group of mice. This data supports a role for caspases in the catabolic events in muscle involved in the cancer cachexia syndrome. © 2001 Cancer Research Campaign.

Exploration of steroselective cleavage of 4, 5-epoycholestane-3, 6-diols and stero controlled epoxidation of cholest-4-en-3 β, 6β-diol-6-acetate

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An examination of the production, heat treatment and mechanical properties of a new wrought magnesium alloy containing 6% Zn. and 1.2% Mn.

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Development and validation of an HPLC method for the rapid and simultaneous determination of 6-mercaptopurine and four of its metabolites in plasma and red blood cells

An HPLC method has been developed and validated for the rapid determination of mercaptopurine and four of its metabolites; thioguanine, thiouric acid, thioxanthine and methylmercaptopurine in plasma and red blood cells. The method involves a simple treatment procedure based on deproteinisation by perchloric acid followed by acid hydrolysis and heating for 45min at 100 degrees C. The developed method was linear over the concentration range studied with a correlation coefficient >0.994 for all compounds in both plasma and erythrocytes. The lower limits of quantification were 13, 14, 3, 2, 95pmol/8 x 10(8) RBCs and 2, 5, 2, 3, 20ng/ml plasma for thioguanine, thiouric acid, mercaptopurine, thioxanthine and methylmercaptopurine, respectively. The method described is selective and sensitive enough to analyse the different metabolites in a single run under isocratic conditions. Furthermore, it has been shown to be applicable for monitoring these metabolites in paediatric patients due to the low volume requirement (200microl of plasma or erythrocytes) and has been successfully applied for investigating population pharmacokinetics, pharmacogenetics and non-adherence to therapy in these patients.

One- and two-step spin-crossover behavior of [Fe(II)(isoxazole)6]2+ and the structure and magnetic properties of triangular [Fe(III)3O(OAc)6(isoxazole)3][ClO4)]

The structure and spin-crossover magnetic behavior of [FeII16][BF4]2 (1 = isoxazole) and [FeII16][ClO4]2 have been studied. [FeII16][BF4]2 undergoes two reversible spin-crossover transitions at 91 and 192 K, and is the first two-step spin transition to undergo a simultaneous crystallographic phase transition, but does not exhibit thermal hysteresis. The single-crystal structure determinations at 260 [space group P3̄, a = 17.4387(4) Å, c = 7.6847(2) Å] and at 130 K [space group P1̄, a = 17.0901(2) Å, b = 16.7481(2) Å, c = 7.5413(1) Å, α = 90.5309(6)°, β = 91.5231(6)°, γ = 117.8195(8)°] reveal two different iron sites, Fe1 and Fe2, in a 1:2 ratio. The room-temperature magnetic moment of 5.0 μB is consistent with high-spin Fe(II). A plateau in μ(T) having a moment of 3.3 μB centered at 130 K suggests a mixed spin system of some high-spin and some low-spin Fe(II) molecules. On the basis of the Fe−N bond distances at the two temperatures, and the molar fraction of high-spin molecules at the transition plateau, Fe1 and Fe2 can be assigned to the 91 and 192 K transitions, respectively. [FeII16][ClO4]2 [space group P3̄, a = 17.5829(3) Å, c = 7.8043(2) Å, β = 109.820 (3)°, T = 295 K] also possesses Fe1:Fe2 in a 1:2 ratio, and magnetic measurements show a single spin transition at 213 K, indicating that both Fe1 and Fe2 undergo a simultaneous spin transition. [FeII16][ClO4]2 slowly decomposes in solutions containing acetic anhydride to form [FeIII3O(OAc)613][ClO4] [space group I2, a = 10.1547(7) Å, b = 16.5497(11) Å, c = 10.3205(9) Å, β = 109.820 (3)°, T = 200 K]. The isosceles Fe3 unit contains two Fe···Fe distances of 3.2844(1) Å and a third Fe···Fe distance of 3.2857(1) Å. The magnetic data can be fit to a trinuclear model with ℋ = −2J(S1·S2 + S2·S3) − 2J13(S1·S3), where J = −27.1 and J13 = −32.5 cm-1.

Image Sensors in Security and Medical Applications

This paper briefly reviews CMOS image sensor technology and its utilization in security and medical applications. The role and future trends of image sensors in each of the applications are discussed. To provide the reader deeper understanding of the technology aspects the paper concentrates on the selected applications such as surveillance, biometrics, capsule endoscopy and artificial retina. The reasons for concentrating on these applications are due to their importance in our daily life and because they present leading-edge applications for imaging systems research and development. In addition, review of image sensors implementation in these applications allows the reader to investigate image sensor technology from the technical and from other views as well.

Modeling security and cooperation in wireless networks using game theory

This research involves the design, development, and theoretical demonstration of models resulting in integrated misbehavior resolution protocols for ad hoc networked devices. Game theory was used to analyze strategic interaction among independent devices with conflicting interests. Packet forwarding at the routing layer of autonomous ad hoc networks was investigated. Unlike existing reputation based or payment schemes, this model is based on repeated interactions. To enforce cooperation, a community enforcement mechanism was used, whereby selfish nodes that drop packets were punished not only by the victim, but also by all nodes in the network. Then, a stochastic packet forwarding game strategy was introduced. Our solution relaxed the uniform traffic demand that was pervasive in other works. To address the concerns of imperfect private monitoring in resource aware ad hoc networks, a belief-free equilibrium scheme was developed that reduces the impact of noise in cooperation. This scheme also eliminated the need to infer the private history of other nodes. Moreover, it simplified the computation of an optimal strategy. The belief-free approach reduced the node overhead and was easily tractable. Hence it made the system operation feasible. Motivated by the versatile nature of evolutionary game theory, the assumption of a rational node is relaxed, leading to the development of a framework for mitigating routing selfishness and misbehavior in Multi hop networks. This is accomplished by setting nodes to play a fixed strategy rather than independently choosing a rational strategy. A range of simulations was carried out that showed improved cooperation between selfish nodes when compared to older results. Cooperation among ad hoc nodes can also protect a network from malicious attacks. In the absence of a central trusted entity, many security mechanisms and privacy protections require cooperation among ad hoc nodes to protect a network from malicious attacks. Therefore, using game theory and evolutionary game theory, a mathematical framework has been developed that explores trust mechanisms to achieve security in the network. This framework is one of the first steps towards the synthesis of an integrated solution that demonstrates that security solely depends on the initial trust level that nodes have for each other.^

Human Security and Crime in Latin America: The political Capital and Political Impact of Criminal Groups and Belligerents Involved in Illicit Economies

Organized crime and illegal economies generate multiple threats to states and societies. But although the negative effects of high levels of pervasive street and organized crime on human security are clear, the relationships between human security, crime, illicit economies, and law enforcement are highly complex. By sponsoring illicit economies in areas of state weakness where legal economic opportunities and public goods are seriously lacking, both belligerent and criminal groups frequently enhance some elements of human security of the marginalized populations who depend on illicit economies for basic livelihoods. Even criminal groups without a political ideology often have an important political impact on the lives of communities and on their allegiance to the State. Criminal groups also have political agendas. Both belligerent and criminal groups can develop political capital through their sponsorship of illicit economies. The extent of their political capital is dependent on several factors. Efforts to defeat belligerent groups by decreasing their financial flows through suppression of an illicit economy are rarely effective. Such measures, in turn, increase the political capital of anti-State groups. The effectiveness of anti-money laundering measures (AML) also remains low and is often highly contingent on specific vulnerabilities of the target. The design of AML measures has other effects, such as on the size of a country’s informal economy. Multifaceted anti-crime strategies that combine law enforcement approaches with targeted socio-economic policies and efforts to improve public goods provision, including access to justice, are likely to be more effective in suppressing crime than tough nailed-fist approaches. For anti-crime policies to be effective, they often require a substantial, but politically-difficult concentration of resources in target areas. In the absence of effective law enforcement capacity, legalization and decriminalization policies of illicit economies are unlikely on their own to substantially reduce levels of criminality or to eliminate organized crime. Effective police reform, for several decades largely elusive in Latin America, is one of the most urgently needed policy reforms in the region. Such efforts need to be coupled with fundamental judicial and correctional systems reforms. Yet, regional approaches cannot obliterate the so-called balloon effect. If demand persists, even under intense law enforcement pressures, illicit economies will relocate to areas of weakest law enforcement, but they will not be eliminated.

Disciplining democracy: United Nations peacekeeping, international security and democratization in the post -Cold War era

After the end of the Cold War, democratization and good governance became the organizing concepts for activities of the United Nations, regional organizations and states in the fields of peace, development and security. How can this increasing interest in democratization and its connection with international security be explained? This dissertation applies the theoretical tools developed by Michel Foucault in his discussions of disciplinarity and government to the analysis of the United Nations debate on democracy in the 1990s, and of two United Nations pro-democracy peacekeeping operations and their aftermath: the United Nations interventions in Haiti and Croatia. It probes “how” certain techniques of power came into being and describes their effects, using as data the texts that elaborate the United Nations understanding of democracy and the texts that constitute peacekeeping. ^ In the face of the proliferation of unpredictable threats in the last decades of the twentieth century a new form of international power emerged. Order in the international arena increasingly was maintained through activities aimed at reducing risk and increasing predictability through the normalization of “rogue” states. The dissertation shows that in the context of these activities, which included but were not limited to UN peacekeeping, normality was identified with democracy, non-democratic regimes with international threats, and democratization with international security. “Good governance” doctrines translated the political debate on democracy into the technical language of functioning state institutions. International organizations adopted good governance as the framework that made democratization a universal task within the reach of their expertise. In Haiti, the United Nations engaged in efforts to transform punishment institutions (the judiciary, police and the prison) into disciplined and disciplinary machines. In Croatia, agreements signed in the context of peacekeeping established in detail the rules of functioning of administrations and the monitoring mechanisms for their implementation. However, in Haiti, the institutions promoted were not sustainable. And in Croatia reforms are stalled by lack of consensus. ^ This dissertation puts efforts to bring about democracy through peacekeeping in the context of a specific modality of power and suggests caution in engaging in universal normalizing endeavors. ^

Consolidating Security and Development in Colombia: Lessons for Peru and Panama

Colombia's increasingly effective efforts to mitigate the power of the FARC and other illegitimately armed groups in the country can offer important lessons for the Peruvian government as it strives to prevent a resurgence of Sendero Luminoso and other illegal non-state actors. Both countries share certain particular challenges: deep economic, social, and in the case of Peru ethnic divisions, the presence of and/or the effects of violent insurgencies, a large-scale narcotics production and trafficking, and a history of weak state presence in large tracts of isolated and scarcely-populated areas. Important differences exist, however in the nature of the insurgencies in the two countries, the government response to them and the nature of government and society that affects the applicability of Colombia's experience to Peru. The security threat to Panama from drug trafficking and Colombian insurgents --often a linked phenomenon-- are in many ways different from the drug/insurgent factor in Colombia itself and in Peru, although there are similar variables. Unlike the Colombian and Peruvian cases, the security threat in Panama is not directed against the state, there are no domestic elements seeking to overthrow the government -- as the case of the FARC and Sendero Luminoso, security problems have not spilled over from rural to urban areas in Panama, and there is no ideological component at play in driving the threat. Nor is drug cultivation a major factor in Panama as it is in Colombia and Peru. The key variable that is shared among all three cases is the threat of extra-state actors controlling remote rural areas or small towns where state presence is minimal. The central lesson learned from Colombia is the need to define and then address the key problem of a "sovereignity gap," lack of legitimate state presence in many part of the country. Colombia's success in broadening the presence of the national government between 2002 and the presence is owed to many factors, including an effective national strategy, improvements in the armed forces and police, political will on the part of government for a sustained effort, citizen buy-in to the national strategy, including the resolve of the elite to pay more in taxes to bring change about, and the adoption of a sequenced approach to consolidated development in conflicted areas. Control of territory and effective state presence improved citizen security, strengthened confidence in democracy and the legitimate state, promoted economic development, and helped mitigate the effect of illegal drugs. Peru can benefit from the Colombian experience especially in terms of the importance of legitimate state authority, improved institutions, gaining the support of local citizens, and furthering development to wean communities away from drugs. State coordinated "integration" efforts in Peru as practiced in Colombia have the potential for success if properly calibrated to Peruvian reality, coordinated within government, and provided with sufficient resources. Peru's traditionally weak political institutions and lack of public confidence in the state in many areas of the country must be overcome if this effort is to be successful.