Small Scale AES Toolbox: Algebraic and Propositional Formulas, Circuit-Implementations and Fault Equations

Cryptography is one of the key technologies ensuring security in the digital domain. As such, its primitives and implementations have been extensively analyzed both from a theoretical, cryptoanalytical perspective, as well as regarding their capabilities to remain secure in the face of various attacks. One of the most common ciphers, the Advanced Encryption Standard (AES) (thus far) appears to be secure in the absence of an active attacker. To allow for the testing and development of new attacks or countermeasures a small scale version of the AES with a variable number of rounds, number of rows, number of columns and data word size, and a complexity ranging from trivial up to the original AES was developed. In this paper we present a collection of various implementations of the relevant small scale AES versions based on hardware (VHDL and gate-level), algebraic representations (Sage and CoCoA) and their translations into propositional formulas (in CNF). Additionally, we present fault attack equations for each version. Having all these resources available in a single and well structured package allows researchers to combine these different sources of information which might reveal new patterns or solving strategies. Additionally, the fine granularity of difficulty between the different small scale AES versions allows for the assessment of new attacks or the comparison of different attacks

Immunohistochemical localization of collagen types I and VI in human skin wounds

A total of 74 human skin wounds were investigated and collagen types I and VI were localized in the wound area by immunohistochemistry. Collagen type I appeared in the form of ramifying string-like structures after approximately 5–6 days, but positive reactions in the form of a spot-like staining around isolated fibroblasts also occurred in a skin wound aged 4 days. Collagen VI was detectable after a post-infliction interval of at least 3 days showing a strongly positive reacting network associated with fibroblasts in the wound area. Both collagens appeared almost constantly after a wound age of 6–7 clays and could also be found in wounds aged a few months. Therefore, although a positive reaction for collagen type I in the form of string-like and ramifying structures around wound fibroblasts indicates a wound age of at least 5–6 days, a spot-like positive staining for collagen type I cannot exclude a wound age of at least 4 days. A positive staining for collagen type VI represents a post-infliction time of 3 days or more. The almost constant appearance of these collagen types suggests that negative results in a sufficient number of specimens indicate a wound age of less than 6–7 days, but cannot completely exclude longer post-infliction intervals. Since collagen type I and VI are also found in the granulation/scar tissue of lesions with advanced wound age, the immunohistochemical analysis of these proteins provides no further information for an age determination of older skin wounds

Emergence and persistence of inefficient states

We present a theory of the emergence and persistence of inefficient states based on patronage politics. The society consists of rich and poor. The rich are initially in power, but expect to transition to democracy, which will choose redistributive policies. Taxation requires the employment of bureaucrats. By choosing an inefficient state structure, the rich may be able to use patronage and capture democratic politics, so reducing the amount of redistribution in democracy. Moreover, the inefficient state creates its own constituency and tends to persist over time. Intuitively, an inefficient state structure creates more rents for bureaucrats than would an efficient one. When the poor come to power in democracy, they will reform the structure of the state to make it more efficient so that higher taxes can be collected at lower cost and with lower rents for bureaucrats. Anticipating this, when the society starts out with an inefficient organization of the state, bureaucrats support the rich, who set lower taxes but also provide rents to bureaucrats. We obtain that the rich–bureaucrats coalition may also expand the size of bureaucracy excessively so as to generate enough political support. The model shows that an equilibrium with an inefficient state is more likely to arise when there is greater income inequality, when bureaucratic rents take intermediate values, and when individuals are sufficiently forward-lookin

A Measles Epidemic Threshold in a Highly Vaccinated Population

BACKGROUND: Mass vaccination against measles has successfully lowered the incidence of the disease and has changed the epidemic pattern from a roughly biennial cycle to an irregular sequence of outbreaks. A possible explanation for this sequence of outbreaks is that the vaccinated population is protected by solid herd immunity. If so, we would expect to see the fraction of susceptible individuals remaining below an epidemic threshold. An alternative explanation is the occurrence of occasional localised lapses in herd immunity that allow for major outbreaks in areas with a low vaccine coverage. In that case, we would expect the fraction of susceptible individuals to exceed an epidemic threshold before outbreaks occur. These two explanations for the irregular sequence of measles outbreaks can be tested against observations of both the fraction of susceptible individuals and infection attack rates. METHODS AND FINDINGS: We have estimated both the fraction of susceptible individuals at the start of each epidemic year and the infection attack rates for each epidemic year in the Netherlands over a 28-y period. During this period the vaccine coverage averaged 93%, and there was no sustained measles transmission. Several measles outbreaks occurred in communities with low vaccine coverage, and these ended without intervention. We show that there is a clear threshold value for the fraction of susceptible individuals, below which only minor outbreaks occurred, and above which both minor and major outbreaks occurred. A precise, quantitative relationship exists between the fraction of susceptible individuals in excess of this threshold and the infection attack rate during the major outbreaks. CONCLUSION: In populations with a high but heterogeneous vaccine coverage, measles transmission can be interrupted without establishing solid herd immunity. When infection is reintroduced, a major outbreak can occur in the communities with low vaccine coverage. During such a major outbreak, each additional susceptible individual in excess of the threshold is associated with almost two additional infections. This quantitative relationship offers potential for anticipating both the likelihood and size of future major outbreaks when measles transmission has been interrupted

Financial firm bankruptcies, international stock markets, and investor sentiment

We consider bankruptcy announcements of large financial institutions in the United States and examine their impact on an international sample of 66 stock market indices. Employing an event‐study methodology, we find that stock markets exhibit strong adverse reaction in the aftermath of such announcements. Further, we develop a surprise measure, based on the country‐level investor sentiment, and find that stock markets in negatively surprised countries respond quickly by sustaining significantly larger declines in the first three trading days following the announcements. Finally, we examine the reaction of stock markets, conditional on the economic classification of their home countries, and find that stock markets in developing (developed) economies are associated with substantially larger (smaller) economic losses

The formation of professional identity in medical students: considerations for educators

<b>Context</b> Medical education is about more than acquiring an appropriate level of knowledge and developing relevant skills. To practice medicine students need to develop a professional identity – ways of being and relating in professional contexts.<p></p> <b>Objectives</b> This article conceptualises the processes underlying the formation and maintenance of medical students’ professional identity drawing on concepts from social psychology.<p></p> <b>Implications</b> A multi-dimensional model of identity and identity formation, along with the concepts of identity capital and multiple identities, are presented. The implications for educators are discussed.<p></p> <b>Conclusions</b> Identity formation is mainly social and relational in nature. Educators, and the wider medical society, need to utilise and maximise the opportunities that exist in the various relational settings students experience. Education in its broadest sense is about the transformation of the self into new ways of thinking and relating. Helping students form, and successfully integrate their professional selves into their multiple identities, is a fundamental of medical education

Cell shape analysis of random tessellations based on Minkowski tensors

To which degree are shape indices of individual cells of a tessellation characteristic for the stochastic process that generates them? Within the context of stochastic geometry and the physics of disordered materials, this corresponds to the question of relationships between different stochastic models. In the context of image analysis of synthetic and biological materials, this question is central to the problem of inferring information about formation processes from spatial measurements of resulting random structures. We address this question by a theory-based simulation study of shape indices derived from Minkowski tensors for a variety of tessellation models. We focus on the relationship between two indices: an isoperimetric ratio of the empirical averages of cell volume and area and the cell elongation quantified by eigenvalue ratios of interfacial Minkowski tensors. Simulation data for these quantities, as well as for distributions thereof and for correlations of cell shape and volume, are presented for Voronoi mosaics of the Poisson point process, determinantal and permanental point processes, and Gibbs hard-core and random sequential absorption processes as well as for Laguerre tessellations of polydisperse spheres and STIT- and Poisson hyperplane tessellations. These data are complemented by mechanically stable crystalline sphere and disordered ellipsoid packings and area-minimising foam models. We find that shape indices of individual cells are not sufficient to unambiguously identify the generating process even amongst this limited set of processes. However, we identify significant differences of the shape indices between many of these tessellation models. Given a realization of a tessellation, these shape indices can narrow the choice of possible generating processes, providing a powerful tool which can be further strengthened by density-resolved volume-shape correlations.Comment: Chapter of the forthcoming book "Tensor Valuations and their Applications in Stochastic Geometry and Imaging" in Lecture Notes in Mathematics edited by Markus Kiderlen and Eva B. Vedel Jense

Negative phenotypic and genetic associations between copulation duration and longevity in male seed beetles

Reproduction can be costly and is predicted to trade-off against other characters. However, while these trade-offs are well documented for females, there has been less focus on aspects of male reproduction. Furthermore, those studies that have looked at males typically only investigate phenotypic associations, with the underlying genetics often ignored. Here, we report on phenotypic and genetic trade-offs in male reproductive effort in the seed beetle, Callosobruchus maculatus. We find that the duration of a male's first copulation is negatively associated with subsequent male survival, phenotypically and genetically. Our results are consistent with life-history theory and suggest that like females, males trade-off reproductive effort against longevity

Urban tourism and population change: Gentrification in the age of mobilities

The prepandemic unbridled growth of tourism has triggered a significant debate regarding the future of cities; several authors suggest that neighbourhood change produced by tourism should be conceived as a form of gentrification. Yet research on population shifts—a fundamental dimension of gentrification—in such neighbourhoods is scarce. Our exploration of the Gòtic area in Barcelona, using quantitative and qualitative techniques, reveals a process of population restructuring characterised by a decrease of long-term residents and inhabited dwellings, and the arrival of young and transnational gentrifiers that are increasingly mobile and form a transient population. We then use some insights from the mobilities literature to make sense of these results. In the gentrification of the Gòtic, the attractiveness of the area for visitors and for a wider palette of transnational dwellers feeds one another, resulting in an uneven negotiation whereby more wealthy and ‘footloose’ individuals gain access and control of space and housing over less mobile and more dependent populations.info:eu-repo/semantics/publishedVersio