Substrate-dependent bacterivory by intertidal benthic copepods

The trophic importance of bacteria to harpacticoid copepods in intertidal areas remains poorly understood, and so do the mechanisms of bacterial feeding. It is, for instance, unclear whether harpacticoids directly target bacterial cells, or merely co-ingest them with substrates to which bacterial cells may be attached. Here, we investigate bacterial uptake and substrate requirement for four mud intertidal species (Microarthridion littorale, Platychelipus littoralis, Delavalia palustris, Nannopus palustris) by means of 13C-labeled bacteria and biomarker fatty acids (FA). Bacterial uptake strongly depended on grazing on a primary food source but bacterial ingestion rates were low and no clear indication of copepods directly targeting bacteria was found. Delavalia was the only species that accumulated bacteria-derived FA and gained in polyunsaturated FA (PUFA) probably through bioconversion of bacteria-derived FA. In general, however, our results suggest that bacteria represent a relatively minor and low-quality food for intertidal harpacticoid copepods

Fast Leakage Assessment

We describe a fast technique for performing the computationally heavy part of leakage assessment, in any statistical moment (or other property) of the leakage samples distributions. The proposed technique outperforms by orders of magnitude the approach presented at CHES 2015 by Schneider and Moradi. We can carry out evaluations that before took 90 CPU-days in 4 CPU-hours (about a 500-fold speed-up). As a bonus, we can work with exact arithmetic, we can apply kernel-based density estimation methods, we can employ arbitrary pre-processing functions such as absolute value to power traces, and we can perform information-theoretic leakage assessment. Our trick is simple and elegant, and lends itself to an easy and compact implementation. We fit a prototype implementation in about 130 lines of C code

Texture and mineralogy influence on durability: The Macigno sandstone

The behaviour of ornamental stones in response to environmental changes or interactions is crucial when dealing with the conservation of cultural heritage.Weathering factors affect each rock differently, depending on structure, mineralogy, and extraction and implementation techniques. This work focuses on the Macigno sandstone, a dimension stone often employed in Tuscany over the centuries. A thorough mineralogical (optical microscopy, scanning electron microscopy and X-ray powder diffraction) and petrophysical characterization (i.e. mercury intrusion porosimetry, X-ray computed tomography, hygroscopic adsorption behaviour, ultrasounds, image analysis and capillary uptake) was made of the sandstone type extracted in the area of Greve in Chianti. The lithotype shows mineralogical (i.e. presence of mixed-layer phyllosilicates) and microporosimetric features, leading to a high susceptibility to relative humidity variation. Moreover, the influence of swelling minerals is related to weathering due to saline solution. The joint application of petrographic and petrophysical techniques allows an understanding of the characteristic weathering pattern of exfoliation (i.e. detachment of multiple thin stone layers, centimetre scale, that are sub-parallel to the stone surface)

Understanding the microstructure of mortars for cultural heritage using X-ray CT and MIP

In this study, the microstructure of mock-up mortar specimens for a historic environment, composed of different mixtures, was studied using mercury intrusion porosity (MIP) and micro-computed tomography (\ub5CT), highlighting the advantages and drawbacks of both techniques. Po-rosity, sphericity, and pores size distribution were studied, evaluating changes according to mortar composition (aerial and hydraulic binders, quartz sand, and crushed limestone aggregate). The \ub5CT results were rendered using 3D visualization software, which provides complementary information for the interpretation of the data obtained using 3D data-analysis software. Moreover, \ub5CT contrib-utes to the interpretation of MIP results of mortars. On the other hand, MIP showed significant ink-bottle effects in lime and cement mortars samples that should be taken into account when interpret-ing the results. Moreover, the MIP results highlighted how gypsum mortar samples display a porosity distribution that is best studied using this technique. This multi-analytical approach provides important insights into the interpretation of the porosimetric data obtained. This is crucial in the characterization of mortars and provides key information for the study of building materials and cultural heritage conservation

Efficiency assessment of hybrid coatings for natural building stones : advanced and multi-scale laboratory investigation

The efficiency of a hybrid patented consolidant (PAASi) and two commercially available hybrid coatings (a consolidant named AlSiX and a hydrophobic product named WS3) properly modified was assessed on a calcarenite substrate. Test routines based on standard recommendations were first applied to evaluate the performances of the consolidant and protective treatments, while the investigation of additional aspects such as penetration depth and interaction with the substrate was achieved by a multi-scale approach based on classic intrusion methods (mercury intrusion porosimetry) and Drilling Resistance Measurement System (DRMS), combined with non-invasive imaging techniques (X-ray computed micro-tomography and neutron radiography) and small angle neutron scattering (SANS). A distinct interaction of the products with the pore network of the stone was quantified in the range 0.007–200 µm. Their effects on capillary water absorption were also visualized with neutron imaging. The suitability of the products on the selected substrate was discussed, highlighting also how the applied routine can support conservation material studies. The results indicated that the Al-Si-based product led to unwanted effects. Alternative application methods and/or curing procedures have to be explored to overtake these undesirable changes. On the contrary, the polyamidoamine-based product seemed to be more suitable for calcarenite substrates conservation. The performances of the hydrophobic coating, when used in combination with consolidants, were strictly influenced by the pre-consolidation of the substrate

A First-Order SCA Resistant AES without Fresh Randomness

Since the advent of Differential Power Analysis (DPA) in the late 1990s protecting embedded devices against Side-Channel Analysis (SCA) attacks has been a major research effort. Even though many different first-order secure masking schemes are available today, when applied to the AES S-box they all require fresh random bits in every evaluation. As the quality criteria for generating random numbers on an embedded device are not well understood, an integrated Random Number Generator (RNG) can be the weak spot of any protected implementation and may invalidate an otherwise secure implementation. We present a new construction based on Threshold Implementations and Changing of the Guards to realize a first-order secure AES with zero per-round randomness. Hence, our design does not need a built-in RNG, thereby enhancing security and reducing the overhead

Multi-scale laboratory routine in the efficacy assessment of conservative products for natural stones

The evaluation of conservative treatments’ efficacy on natural building stones are usually based on standard recommendation routines finalized to evaluate compatibility and harmfulness of products in turn of the substrate. However, the visualization and the quantification of products inside pore structure of natural stones is not immediate through standard tests, so that imaging and advanced techniques are recently proposed in material conservation field to improve knowledge on penetration depth, modification of pore-air interface at different scale and monitor dynamic absorption processes. Moreover, natural stones are usually characterized by complex structure, which changes due to conservative treatments have to be inspected at different scale (from micrometer to nanometer). In this prospective, the assessment of laboratory practices able to integrate multiscale methods and give back a complete overview on interaction between new conservative formulates and natural stones is of high interest. In this paper, we propose a methodological routine for efficacy assessment of conservative products, incorporating classical and innovative nondestructive techniques. Validation of the workflow has been verified on a high porous natural stone treated with new hybrid formulates appropriately customized for conservation issues. • The study intends to add new insights on problems related to consolidation of high porous carbonate stone, application methods in consolidating natural stones and methods to evaluate efficacy of new products.• A multi-scale laboratory investigation procedure is proposed by integrating standard and innovative nondestructive methods. Merits and limits of each applied method are discussed during validation.• The possibility to incorporate standard routines and/or substitute destructive testing with non-destructive ones seem to be a valid alternative to evaluate efficiency and monitor behavior of stones treated with consolidating products

Constructing TI-Friendly Substitution Boxes Using Shift-Invariant Permutations

The threat posed by side channels requires ciphers that can be efficiently protected in both software and hardware against such attacks. In this paper, we proposed a novel Sbox construction based on iterations of shift-invariant quadratic permutations and linear diffusions. Owing to the selected quadratic permutations, all of our Sboxes enable uniform 3-share threshold implementations, which provide first order SCA protections without any fresh randomness. More importantly, because of the shift-invariant property, there are ample implementation trade-offs available, in software as well as hardware. We provide implementation results (software and hardware) for a four-bit and an eight-bit Sbox, which confirm that our constructions are competitive and can be easily adapted to various platforms as claimed. We have successfully verified their resistance to first order attacks based on real acquisitions. Because there are very few studies focusing on software-based threshold implementations, our software implementations might be of independent interest in this regard