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Widespread use of string solvers in the formal analysis of string-heavy programs has led to a growing demand for more efficient and reliable techniques which can be applied in this context. Designing practical algorithms for the (generally undecidable) satisfiability problem for systems of string constraints requires a deep understanding of the structure of constraints present in the targeted cases. In this paper, we first investigate relevant benchmarks containing regular expression membership predicates, extract a series of first order logic theories, and prove the decidability, respectively undecidability, of their satisfiability problem. Further, building on the theoretical results, we present a novel length-aware solving algorithm for the quantifier-free first-order theory over regular expression membership predicates and linear arithmetic over string length. We implement and evaluate this algorithm and related heuristics in the Z3 theorem prover. Besides the theoretical aspects leading to this algorithm, a crucial insight that underpins it is that real-world regex and string formulas contain a wealth of information about upper and lower bounds on lengths of strings, and such information can be used very effectively to simplify operations on automata representing regular expressions. Additionally, we present several novel general heuristics, such as the prefix/suffix method, that can be used to make a variety of regex solving algorithms more efficient in practice. We showcase the power of our algorithm and heuristics via an extensive empirical evaluation over a large and diverse benchmark of 57256 regex-heavy instances, almost 75% of which are derived from industrial applications or contributed by other solver developers. Our solver outperforms five other state-of-the-art string solvers over this benchmark. [ABSTRACT FROM AUTHOR]

Near infrared spectroscopy is proposed as a method for continuous characterization of ground oilseed concentration in diluted solid liquid dispersions. The effect of operational parameters, such as flow rate and temperature on the stability and reliability of the in-line measurement was investigated. Moreover, in order to widen the applicability of the approach to different materials, the variety of oilseed, the particle size distribution, and the chemistry of the suspending liquid carrier were all changed, and their influence assessed through principal component analysis. Simple multivariate techniques were efficiently used to regress spectral features against known values of dispersed solids concentration. The calibration, obtained after internal cross validation, proved to give values of coefficient of determination always higher than 0.95, ratio of performance to deviation higher than 4, and comparably reduced root mean squared error of cross validation. Instantaneous concentration prediction were characterized by oscillations much dependent on the dispersed solids particle size, being their amplitude lower in the case of finer particles. Those oscillations were characterized through the coefficient of variation that, at steady state, gave values small enough to constitute an effective parameter to tackle mixing end-point, hence constituting a novel way to assess homogeneity during powder incorporation in liquids. [ABSTRACT FROM AUTHOR]

Marine ecosystems are subject to global and local impacts, both contributing to dramatic changes in coastal communities. Assessing such changes requires time series or the revisitation of sites first surveyed in the past. In both cases, data are not necessarily collected by the same observers, which could lead to a bias in the results. In the Marine Protected Area (MPA) of Capo Carbonara (Sardinia, Italy), established in 1998, rocky reef communities were first assessed in 2000 by two diving scientists. Twenty years later, the same rocky reefs were resurveyed using the same method by two other diving scientists. In both surveys, semi-quantitative data on conspicuous species were collected at five sites in four depth zones, providing the possibility of assessing change over time. To explore the influence of climate and local pressures, existing data on sea surface temperature, resident population, tourism and diving activities were analysed. The reef communities of the Capo Carbonara MPA have distinctly changed over time, mostly under the effect of seawater warming, as highlighted by the occurrence of thermophilic species and by other climate-related indicators. On the other side, species vulnerable to local human pressures have increased over time, demonstrating the effectiveness of the protection measures undertaken by the MPA. Comparing data collected by four different observers in the two periods demonstrated that change over time was significantly greater than variability between the observers. • Revisiting sites monitored in the past allows analysis of change over time. • Data are rarely collected by the same researcher, this may influence sampling quality. • Design of monitoring activities should consider the variability between observers. • A drastic change in reef communities of the Capo Carbonara MPA was observed. • Variability between observers did not hamper detecting change over time. [ABSTRACT FROM AUTHOR]

The objective with synthetic multifunctional nanoarchitecture is to create large suprastructures with interesting functions. For this purpose, lipid bilayer membranes or conducting surfaces have been used as platforms and rigid-rod molecules as shape-persistent scaffolds. Examples for functions obtained by this approach include pores that can act as multicomponent sensors in complex matrices or rigid-rod π-stack architecture for artificial photosynthesis and photovoltaics. [ABSTRACT FROM AUTHOR]