Measuring Security: A Challenge for the Generation

This paper presents an approach to measuring computer security understood as a system property, in the category of similar properties, such as safety, reliability, dependability, resilience, etc. First, a historical discussion of measurements is presented, beginning with views of Hermann von Helmholtz in his 19th century work “Zählen und Messen”. Then, contemporary approaches related to the principles of measuring software properties are discussed, with emphasis on statistical, physical and software models. A distinction between metrics and measures is made to clarify the concepts. A brief overview of inadequacies of methods and techniques to evaluate computer security is presented, followed by a proposal and discussion of a practical model to conduct experimental security measurements

ESR of MnO embedded in silica nanoporous matrices with different topologies

Electron spin resonance (ESR) experiments were performed with antiferromagnetic MnO confined within a porous vycor-type glass and within MCM-type channel matrices. A signal from confined MnO shows two components from crystallized and amorphous MnO and depends on the pore topology. Crystallized MnO within a porous glass shows a behavior having many similarities to the bulk. In contrast with the bulk the strong ESR signal due to disordered "surface" spins is observed below the magnetic transition. With the decrease of channel diameter the fraction of amorphous MnO increases while the amount of crystallized MnO decreases. The mutual influence of amorphous and crystalline MnO is observed in the matrices with a larger channel diameter. In the matrices with a smaller channel diameter the ESR signal mainly originates from amorphous MnO and its behavior is typical for the highly disordered magnetic system.Comment: 7 pages pdf file, 5 figure

Instanton approach to the Langevin motion of a particle in a random potential

We develop an instanton approach to the non-equilibrium dynamics in one-dimensional random environments. The long time behavior is controlled by rare fluctuations of the disorder potential and, accordingly, by the tail of the distribution function for the time a particle needs to propagate along the system (the delay time). The proposed method allows us to find the tail of the delay time distribution function and delay time moments, providing thus an exact description of the long-time dynamics. We analyze arbitrary environments covering different types of glassy dynamics: dynamics in a short-range random field, creep, and Sinai's motion.Comment: 4 pages, 1 figur

Modeling the scaling properties of human mobility

While the fat tailed jump size and the waiting time distributions characterizing individual human trajectories strongly suggest the relevance of the continuous time random walk (CTRW) models of human mobility, no one seriously believes that human traces are truly random. Given the importance of human mobility, from epidemic modeling to traffic prediction and urban planning, we need quantitative models that can account for the statistical characteristics of individual human trajectories. Here we use empirical data on human mobility, captured by mobile phone traces, to show that the predictions of the CTRW models are in systematic conflict with the empirical results. We introduce two principles that govern human trajectories, allowing us to build a statistically self-consistent microscopic model for individual human mobility. The model not only accounts for the empirically observed scaling laws but also allows us to analytically predict most of the pertinent scaling exponents

Global update on the susceptibility of humam influenza viruses to neuraminidase inhibitors 2012-2013

Emergence of influenza viruses with reduced susceptibility to neuraminidase inhibitors (NAIs) is sporadic, often follows exposure to NAIs, but occasionally occurs in the absence of NAI pressure. The emergence and global spread in 2007/2008 of A(H1N1) influenza viruses showing clinical resistance to oseltamivir due to neuraminidase (NA) H275Y substitution, in the absence of drug pressure, warrants continued vigilance and monitoring for similar viruses. Four World Health Organization (WHO) Collaborating Centres for Reference and Research on Influenza and one WHO Collaborating Centre for the Surveillance, Epidemiology and Control of Influenza (WHO CCs) tested 11,387 viruses collected by WHO-recognized National Influenza Centres (NIC) between May 2012 and May 2013 to determine 50% inhibitory concentration (IC50) data for oseltamivir, zanamivir, peramivir and laninamivir. The data were evaluated using normalized IC50 fold-changes rather than raw IC50 data. Nearly 90% of the 11,387 viruses were from three WHO regions: Western Pacific, the Americas and Europe. Only 0.2% (n=27) showed highly reduced inhibition (HRI) against at least one of the four NAIs, usually oseltamivir, while 0.3% (n=39) showed reduced inhibition (RI). NA sequence data, available from the WHO CCs and from sequence databases (n=3661), were screened for amino acid substitutions associated with reduced NAI susceptibility. Those showing HRI were A(H1N1)pdm09 with NA H275Y (n=18), A(H3N2) with NA E119V (n=3) or NA R292K (n=1) and B/Victoria-lineage with NA H273Y (n=2); amino acid position numbering is A subtype and B type specific. Overall, approximately 99% of circulating viruses tested during the 2012-2013 period were sensitive to all four NAIs. Consequently, these drugs remain an appropriate choice for the treatment and prophylaxis of influenza virus infections

Effect of chronic intermittent hypoxia on triglyceride uptake in different tissues

Chronic intermittent hypoxia (CIH) inhibits plasma lipoprotein clearance and adipose lipoprotein lipase (LPL) activity in association with upregulation of an LPL inhibitor angiopoietin-like protein 4 (Angptl4). We hypothesize that CIH inhibits triglyceride (TG) uptake via Angptl4 and that an anti-Angptl4-neutralizing antibody would abolish the effects of CIH. Male C57BL/6J mice were exposed to four weeks of CIH or intermittent air (IA) while treated with Ab (30 mg/kg ip once a week). TG clearance was assessed by [H 3 ]triolein administration retroorbitally. CIH delayed TG clearance and suppressed TG uptake and LPL activity in all white adipose tissue depots, brown adipose tissue, and lungs, whereas heart, liver, and spleen were not affected. CD146+ CD11b α pulmonary microvascular endothelial cells were responsible for TG uptake in the lungs and its inhibition by CIH. Antibody to Angptl4 decreased plasma TG levels and increased TG clearance and uptake into adipose tissue and lungs in both control and CIH mice to a similar extent, but did not reverse the effects of CIH. The antibody reversed the effects of CIH on LPL in adipose tissue and lungs. In conclusion, CIH inactivates LPL by upregulating Angptl4, but inhibition of TG uptake occurs predominantly via an Angptl4/LPL-independent mechanism

Trends in Immunization Completion and Disparities in the Context of Health Reforms: The case study of Tanzania

\ud Of global concern is the decline in under five children mortality which has reversed in some countries in sub Saharan Africa (SSA) since the early 1990 s which could be due to disparities in access to preventive services including immunization. This paper is aimed at determining the trend in disparities in completion of immunization using Tanzania Demographic and Health Surveys (DHS). DHS studies randomly selected representative households from all regions in Tanzania since 1980 s, is repeated every five years in the same enumeration areas. The last three data sets (1990, 1996 and 2004) were downloaded and analyzed using STATA 9.0. The analysis included all children of between 12-23 months who would have completed all vaccinations required at 12 months. Across the time periods 1990, 1996 to 2004/05 the percentage of children completing vaccination was similar (71.0% in 1990, 72.7% in 1996 and 72.3% in 2005). There was no disparity in completion of immunization with wealth strata in 1990 and 1996 (p > 0.05) but not 2004. In 2004/05 there was marked disparity as most poor experienced significant decline in immunization completion while the least poor had significant increase (p < 0.001). All three periods children from households whose head had low education were less likely to complete immunization (p < 0.01). Equity that existed in 1990 and more pronounced in 1996 regressed to inequity in 2005, thus though at national level immunization coverage did not change, but at sub-group there was significant disparity associated with the changing contexts and reforms. To address sub-group disparities in immunization it is recommended to adopt strategies focused at governance and health system to reach all population groups and most poor.\u