On the Complexity of Computing Two Nonlinearity Measures

We study the computational complexity of two Boolean nonlinearity measures: the nonlinearity and the multiplicative complexity. We show that if one-way functions exist, no algorithm can compute the multiplicative complexity in time $2^{O(n)}$ given the truth table of length $2^n$, in fact under the same assumption it is impossible to approximate the multiplicative complexity within a factor of $(2-\epsilon)^{n/2}$. When given a circuit, the problem of determining the multiplicative complexity is in the second level of the polynomial hierarchy. For nonlinearity, we show that it is #P hard to compute given a function represented by a circuit

The global threat of antimicrobial resistance: science for intervention

In the last decade we have witnessed a dramatic increase in the proportion and absolute number of bacterial pathogens resistant to multiple antibacterial agents. Multidrug-resistant bacteria are currently considered as an emergent global disease and a major public health problem. The B-Debate meeting brought together renowned experts representing the main stakeholders (i.e. policy makers, public health authorities, regulatory agencies, pharmaceutical companies and the scientific community at large) to review the global threat of antibiotic resistance and come up with a coordinated set of strategies to fight antimicrobial resistance in a multifaceted approach. We summarize the views of the B-Debate participants regarding the current situation of antimicrobial resistance in animals and the food chain, within the community and the healthcare setting as well as the role of the environment and the development of novel diagnostic and therapeutic strategies, providing expert recommendations to tackle the global threat of antimicrobial resistance

Selection for antimicrobial resistance is reduced when embedded in a natural microbial community

This is the final version. Available from Springer Nature via the DOI in this record.Antibiotic resistance has emerged as one of the most pressing, global threats to public health. In single-species experiments selection for antibiotic resistance occurs at very low antibiotic concentrations. However, it is unclear how far these findings can be extrapolated to natural environments, where species are embedded within complex communities. We competed isogenic strains of Escherichia coli, differing exclusively in a single chromosomal resistance determinant, in the presence and absence of a pig faecal microbial community across a gradient of antibiotic concentration for two relevant antibiotics: gentamicin and kanamycin. We show that the minimal selective concentration was increased by more than one order of magnitude for both antibiotics when embedded in the community. We identified two general mechanisms were responsible for the increase in minimal selective concentration: an increase in the cost of resistance and a protective effect of the community for the susceptible phenotype. These findings have implications for our understanding of the evolution and selection of antibiotic resistance, and can inform future risk assessment efforts on antibiotic concentrations.Medical Research Council (MRC)European Commissio

Classical R-matrix theory for bi-Hamiltonian field systems

The R-matrix formalism for the construction of integrable systems with infinitely many degrees of freedom is reviewed. Its application to Poisson, noncommutative and loop algebras as well as central extension procedure are presented. The theory is developed for (1+1)-dimensional case where the space variable belongs either to R or to various discrete sets. Then, the extension onto (2+1)-dimensional case is made, when the second space variable belongs to R. The formalism presented contains many proofs and important details to make it self-contained and complete. The general theory is applied to several infinite dimensional Lie algebras in order to construct both dispersionless and dispersive (soliton) integrable field systems.Comment: review article, 39 page

New materials and devices for preventing catheter-related infections

Catheters are the leading source of bloodstream infections for patients in the intensive care unit (ICU). Comprehensive unit-based programs have proven to be effective in decreasing catheter-related bloodstream infections (CR-BSIs). ICU rates of CR-BSI higher than 2 per 1,000 catheter-days are no longer acceptable. The locally adapted list of preventive measures should include skin antisepsis with an alcoholic preparation, maximal barrier precautions, a strict catheter maintenance policy, and removal of unnecessary catheters. The development of new technologies capable of further decreasing the now low CR-BSI rate is a major challenge. Recently, new materials that decrease the risk of skin-to-vein bacterial migration, such as new antiseptic dressings, were extensively tested. Antimicrobial-coated catheters can prevent CR-BSI but have a theoretical risk of selecting resistant bacteria. An antimicrobial or antiseptic lock may prevent bacterial migration from the hub to the bloodstream. This review discusses the available knowledge about these new technologies

Cryptanalysis of Masked Ciphers: A not so Random Idea

A new approach to the security analysis of hardware-oriented masked ciphers against second-order side-channel attacks is developed. By relying on techniques from symmetric-key cryptanalysis, concrete security bounds are obtained in a variant of the probing model that allows the adversary to make only a bounded, but possibly very large, number of measurements. Specifically, it is formally shown how a bounded-query variant of robust probing security can be reduced to the linear cryptanalysis of masked ciphers. As a result, the compositional issues of higher-order threshold implementations can be overcome without relying on fresh randomness. From a practical point of view, the aforementioned approach makes it possible to transfer many of the desirable properties of first-order threshold implementations, such as their low randomness usage, to the second-order setting. For example, a straightforward application to the block cipher LED results in a masking using less than 700 random bits including the initial sharing. In addition, the cryptanalytic approach introduced in this paper provides additional insight into the design of masked ciphers and allows for a quantifiable trade-off between security and performance

A call for action to the biomaterial community to tackle antimicrobial resistance

The global surge of antimicrobial resistance (AMR) is a major concern for public health and proving to be a key challenge in modern disease treatment, requiring action plans at all levels. Microorganisms regularly and rapidly acquire resistance to antibiotic treatments and new drugs are continuously required. However, the inherent cost and risk to develop such molecules has resulted in a drying of the pipeline with very few compounds currently in development. Over the last two decades, efforts have been made to tackle the main sources of AMR. Nevertheless, these require the involvement of large governmental bodies, further increasing the complexity of the problem. As a group with a long innovation history, the biomaterials community is perfectly situated to push forward novel antimicrobial technologies to combat AMR. Although this involvement has been felt, it is necessary to ensure that the field offers a united front with special focus in areas that will facilitate the development and implementation of such systems. This paper reviews state of the art biomaterials strategies striving to limit AMR. Promising broad-spectrum antimicrobials and device modifications are showcased through two case studies for different applications, namely topical and implantables, demonstrating the potential for a highly efficacious physical and chemical approach. Finally, a critical review on barriers and limitations of these methods has been developed to provide a list of short and long-term focus areas in order to ensure the full potential of the biomaterials community is directed to helping tackle the AMR pandemic

Surviving Sepsis Campaign: International guidelines for management of severe sepsis and septic shock: 2008

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

The First Thorough Side-Channel Hardware Trojan

Hardware Trojans have gained high attention in academia, industry and by government agencies. The effective detection mechanisms and countermeasures against such malicious designs are only possible when there is a deep understanding of how hardware Trojans can be built in practice. In this work, we present a mechanism which shows how easily a stealthy hardware Trojan can be inserted in a provably-secure side-channel analysis protected implementation. Once the Trojan is triggered, the malicious design exhibits exploitable side-channel leakage leading to successful key recovery attacks. Such a Trojan does not add or remove any logic (even a single gate) to the design which makes it very hard to detect. In ASIC platforms, it is indeed inserted by subtle manipulations at the sub-transistor level to modify the parameters of a few transistors. The same is applicable on FPGA applications by changing the routing of particular signals, leading to null resource utilization overhead. The underlying concept is based on a secure masked hardware implementation which does not exhibit any detectable leakage. However, by running the device at a particular clock frequency one of the requirements of the underlying masking scheme is not fulfilled anymore, i.e., the Trojan is triggered, and the device\u27s side-channel leakage can be exploited. Although as a case study we show an application of our designed Trojan on an FPGA-based threshold implementation of the PRESENT cipher, our methodology is a general approach and can be applied on any similar circuit