Generic Mixtures Research Articles

Robustness of traveling states in generic nonreciprocal mixtures.

Emergent nonreciprocal interactions violating Newton's third law are widespread in out-of-equilibrium systems. Phase separating mixtures with such interactions exhibit traveling states with no equilibrium counterpart. Using extensive Brownian dynamics simulations, we investigate the existence and stability of such traveling states in a generic nonreciprocal particle system. By varying a broad range of parameters including aggregate state of mixture components, diffusivity, degree of nonreciprocity, effective spatial dimension and density, we determine that traveling states do exist below the predator-prey regime, but nonetheless are only found in a narrow region of the parameter space. Our work also sheds light on the physical mechanisms for the disappearance of traveling states when relevant parameters are being varied, and has implications for a range of nonequilibrium systems including nonreciprocal phase separating mixtures, nonequilibrium pattern formation and predator-prey models.

Chemical Mixtures in the EU Population: Composition and Potential Risks.

Regulating chemical mixtures is a complex scientific and policy task. The aim of this study was to investigate typical mixtures and their potential risks based on internal exposure levels in the European population. Based on human biomonitoring (HBM) data made available via the HBM4EU project, we derived generic mixtures representative of a median (P50) and a worst-case scenario (P95) for adults and children. We performed a mixture risk assessment based on HBM concentrations, health-based guidance values (HBGVs) as internal thresholds of concern, and the conservative assumption of concentration addition applied across different toxicological endpoints. Maximum cumulative ratios (MCRs) were calculated to characterize the mixture risk. The mixtures comprise 136 biomarkers for adults and 84 for children, although concentration levels could be quantified only for a fraction of these. Due to limited availability of HBGVs, the mixture risk was assessed for a subset of 20 substance-biomarker pairs for adults and 17 for children. The mixture hazard index ranged from 2.8 (P50, children) to 9.2 (P95, adults). Six to seven substances contributed to over 95% of the total risk. MCR values ranged between 2.6 and 5.5, which is in a similar range as in previous studies based on human external exposures assessments. The limited coverage of substances included in the calculations and the application of a hazard index across toxicological endpoints argue for caution in the interpretation of the results. Nonetheless the analyses of MCR and MAFceiling can help inform a possible mixture assessment factor (MAF) applicable to single substance risk assessment to account for exposure to unintentional mixtures.

Nature‐Inspired Circular‐Economy Recycling for Proteins: Proof of Concept (Adv. Mater. 44/2021)

Protein Recycling In article number 2104581, Sebastian Josef Maerkl, Francesco Stellacci, and co-workers introduce an idealized representation of nature-inspired circular-economy recycling (NaCRe) for proteins, a recycling approach where generic mixtures of protein-based materials are depolymerized into their constituent amino acids, which in turn are used as the only source of monomers to produce new protein-based materials that are unrelated to the parent ones, outside living organisms. Illustration created by SciencePicture.Co.

At the Gates: The Tantalum-Rich Phase Hf3Ta2O11 and its Commensurately Modulated Structure

Generic mixtures in the system (Zr,Hf)O2-(Nb,Ta)2O5 are employed as tunable gate materials for field-effect transistors. Whereas production processes and target compositions are well-defined, resulting crystal structures are vastly unexplored. In this study, we summarize the sparse reported findings and present the new phase Hf3Ta2O11 as synthesized via a sol-gel route. Its commensurately modulated structure represents the hitherto unknown, metal(V)-richest member of the family (Zr,Hf) x(Nb,Ta)2O2 x+5. Based on electron, neutron, and X-ray diffraction, the crystal structure is described within modern superspace [Hf1.2Ta0.8O4.4, Z = 2, a = 4.7834(13), b = 5.1782(17), c = 5.064(3) Å, q = 1/5 c*, orthorhombic, superspace group Xmcm(00γ) s00] and supercell formalisms [Hf3Ta2O11, Z = 4, a = 4.7834(13), b = 5.1782(17), c = 25.320(13) Å, orthorhombic, space group Pbnm]. Transmission electron microscopy shows the microscopic structure from film-like aggregates down to atomic resolution. Cation ordering within the different available coordination environments is possible, but no significant hint at it is found within the limits of standard diffraction techniques. Hf3Ta2O11 is an unpredicted compound in the above-mentioned oxide systems, in which stability ranges have been disputably fuzzy and established only by syntheses via solid-state routes so far.

Capillary-wave dynamics and interface structure modulation in binary Bose-Einstein condensate mixtures

The localized low-energy interfacial excitations, or Nambu-Goldstone modes, of phase-segregated binary mixtures of Bose-Einstein condensates are investigated analytically by means of a double-parabola approximation (DPA) to the Lagrangian density in Gross-Pitaevskii theory for a system in a uniform potential. Within this model analytic expressions are obtained for the excitations underlying capillary waves or "ripplons" for arbitrary strength $K\,(>1)$ of the phase segregation. The dispersion relation $\omega \propto k^{3/2}$ is derived directly from the Bogoliubov-de Gennes equations in limit that the wavelength $2\pi/k$ is much larger than the healing length $\xi $. The proportionality constant in the dispersion relation provides the static interfacial tension. A correction term in $\omega (k)$ of order $k^{5/2}$ is calculated analytically, entailing a finite-wavelength correction factor $(1+\frac{\sqrt{K-1} \,k\xi}{4\sqrt{2}\,(\sqrt{2}+\sqrt{K-1})})$. This prediction may be tested experimentally using (quasi-)uniform optical-box traps. Explicit expressions are obtained for the structural deformation of the interface due to the passing of the capillary wave. It is found that the amplitude of the wave is enhanced by an amount that is quadratic in the ratio of the phase velocity $\omega/k$ to the sound velocity $c$. For generic asymmetric mixtures consisting of condensates with unequal healing lengths an additional modulation is predicted of the common value of the condensate densities at the interface.

The Power of the Broken: Sir Thomas Browne’s Religio Medici and Aphoristic Writing

An analysis of the generic affiliations and mixtures of Religio Medici helps make sense of certain features of its dazzling intricacies, but it does not consider the shape of the eight extant manuscripts. Especially in two manuscripts whose provenance is linked closely to Browne himself, the text of Religio Medici is broken into smaller portions of prose than are found in the print editions from 1642 onward. Furthermore, in the first manuscript stage of composition and the 1643 authorized edition, Browne divides his meditations by numbers rather than titles. These features suggest that the mode if not the genre of Religio Medici was intended by the author and received by its earliest readers as aphoristic.

Moll Flanders and the Bastard Birth of Realist Character

This essay applies genre theory to the 1722 Moll Flanders in order to outline a new history of character, reinterpreting the accepted division between early modern, “flat” characterization and the ostensibly more complex psychological practice of later realism. In the last fifty years, this contradictory text has become an important site of contention for critics examining narratorial unreliability, the origins of the novel, and nascent modernity. Critics have interpreted its inconsistencies as the result of deliberately designed irony, as the expression of the emerging ideologies of the modern world, or as simple incoherence. At base, however, Moll’s contradictory nature is an exaggeration of the kind of generic process common to many of the narratives of early print culture, a process emphasizing both formulaic repetition and fragmented generic mixture. Moll Flanders is only a more intense, more thoroughly mixed version of these ephemeral narratives, the product of an endemic bastardization of genres that lasts from the 1590s through the 1730s and beyond, particularly inhabiting the lower registers of mass culture. Yet at the same time, the text prefigures the structure and complex ethical and psychological dynamics of later realism. This confluence suggests that the later form of characterization, usually understood as a more concrete representation of individual and social life, is actually a naturalization of the fragmented generic mixtures of the earlier field of narrative. What we see in Moll Flanders , in other words, is the generic instability of early print culture transforming itself into modern character. This text also illuminates the familiar genre theory I use—one that sees genres as variously institutionalized sets of reader expectations—by displaying irony as a kind of generic negotiation.

Predicting acute and chronic effects of wood preservative products in daphnia magna and pseudokirchneriella subcapitata based on the concept of concentration addition

The current European legislation requires that combined effects of the active substances and any substance of concern contained in biocidal products are taken into account in environmental risk assessment. The hypothesis whether the consideration of active substances together with all formulation additives that are labeled as presenting an environmental hazard is sufficient for a reliable environmental risk assessment was tested in the present study by investigating 3 wood preservative products. Relevant single substances in the products, some of their generic mixtures, the biocidal products themselves, and aqueous eluates prepared from the products (representing potential environmental mixtures) were tested for effects on algal growth and Daphnia acute immobilization as well as reproduction. Predictions for the products and the eluates were based on the concept of concentration addition and were mostly found to provide reliable or at least protective estimates for the observed acute and chronic toxicity of the mixtures. The mixture toxicity considerations also indicated that the toxicity of each product was dominated by just 1 of the components, and that assessments based only on the dominating substance would be similarly protective as a full-mixture risk assessment. Yet, there remained uncertainty in some cases that could be related to the toxicity of transformation products, the impact of unidentified formulation additives, or synergistic interaction between active substances and formulation additives.

Experimental Investigations of the Lean Blowout Limit of Different Syngas Mixtures in an Atmospheric, Premixed, Variable-Swirl Burner

An atmospheric, variable-swirl combustor was used to study the influence of syngas composition on the lean blowout (LBO) limit under various flow conditions created at different swirl numbers. The fuels used in the experiments consisted of generic mixtures of CO, H2, and CH4. The results were compared to those for CH4 at the same swirl numbers. The effect of dilution on the LBO limit was studied by adding N2 to the syngas mixture. The swirl number was varied by changing the ratio of axial/tangential flow through the combustor inlet and was determined using laser Doppler anemometry (LDA). A perfectly stirred reactor (PSR) model was used to test whether the experimental results could be explained by changes in chemical kinetics. The experiments showed that increasing the swirl number reduced the LBO equivalence ratio for a given fuel composition. At a certain swirl number, increasing the H2/CO molar ratio of a binary mixture decreased the LBO equivalence ratio significantly. The addition of CH4 to a binary mixture shifted the LBO limit to higher equivalence ratios. N2 dilution increased the LBO equivalence ratio of the syngas mixture; however, the impact was relatively small. The PSR model was able to predict the effect of adding CH4 reasonably well, but it underestimated the effect of the H2/CO molar ratio on the LBO limit.

Computationally efficient method to compare the shape of planar Gaussian mixtures from point samples

We discuss the problem of recognizing the shape of planar objects consisting of blobs that can be modeled as Gaussian mixture densities. We describe an empirical comparison method, assuming a large number of independent samples are given for each distribution. Instead of comparing the Gaussian mixtures directly, we compare the underlying distribution of distances of each mixture. Since distances are invariant under rotations and translations, this provides a workaround to the problem of aligning the objects before comparing them-thus speeding the comparison process. We prove that the distribution of distances is a lossless representation of the shape of generic Gaussian mixtures. Our numerical experiments indicate that, when all the components of the Gaussian mixtures are equally weighted and have the same standard deviation matrix, the proposed method is no less accurate than methods that compare the planar mixtures directly. The extension of our method to the problem of recognizing halftone patterns is briefly discussed.

Mixture toxicity of wood preservative products in the fish embryo toxicity test

Wood preservative products are used globally to protect wood from fungal decay and insects. We investigated the aquatic toxicity of five commercial wood preservative products, the biocidal active substances and some formulation additives contained therein, as well as six generic binary mixtures of the active substances in the fish embryo toxicity test (FET). Median lethal concentrations (LC50) of the single substances, the mixtures, and the products were estimated from concentration-response curves and corrected for concentrations measured in the test medium. The comparison of the experimentally observed mixture toxicity with the toxicity predicted by the concept of concentration addition (CA) showed less than twofold deviation for all binary mixtures of the active substances and for three of the biocidal products. A more than 60-fold underestimation of the toxicity of the fourth product by the CA prediction was detected and could be explained fully by the toxicity of one formulation additive, which had been labeled as a hazardous substance. The reason for the 4.6-fold underestimation of toxicity of the fifth product could not be explained unambiguously. Overall, the FET was found to be a suitable screening tool to verify whether the toxicity of formulated wood preservatives can reliably be predicted by CA. Applied as a quick and simple nonanimal screening test, the FET may support approaches of applying component-based mixture toxicity predictions within the environmental risk assessment of biocidal products, which is required according to European regulations.

Greenberger-Horne-Zeilinger andWentanglement witnesses for the noninteracting Fermi gas

The existence and nature of tripartite entanglement of a noninteracting Fermi gas (NIFG) is investigated. Three classes of parametrized entanglement witnesses (EWs) are introduced with the aim of detecting genuine tripartite entanglement in the three-body reduced density matrix and discriminating between the presence of the two types of genuine tripartite entanglement, $W\B$ and $\mathrm{GHZ}\W$ (the convex set of $B$ states is comprised of mixed states of product and biseparable states; that of $W$ states is comprised of mixed states of $B$ states and $W$-type pure entangled states; and the GHZ (Greenberger-Horne-Zeilinger) set contains generic mixtures of any kind for a tripartite system). By choosing appropriate EW operators, the problem of finding GHZ and $W$ EWs is reduced to linear programming. Specifically, we devise $W$ EWs based on a spin-chain model with periodic boundary conditions, and we construct a class of parametrized GHZ EWs by linearly combining projection operators corresponding to all the different state-vector types arising for a three-fermion system. A third class of EWs is provided by a GHZ stabilizer operator capable of distinguishing $W\B$ from $\mathrm{GHZ}\B$ entanglement, which is not possible with $W$ EWs. Implementing these classes of EWs, it is found that all states containing genuine tripartite entanglement are of $W$ type, and hence states containing $\mathrm{GHZ}\W$ genuine tripartite entanglement do not arise. Some genuine tripartite entangled states that have a positive partial transpose (PPT) with respect to some bipartition are detected. Finally, it is demonstrated that a NIFG does not exhibit ``pure'' $W\B$ genuine tripartite entanglement: three-party entanglement without any separable or biseparable admixture does not occur.

Ambiguity as Agent in Pushkin's and Shakespeare's Historical Tragedies

The question of Shakespeare's influence on Pushkin's work in the period beginning 1824-25 has often been examined in critical works on Pushkin. This influence has generally been construed as one of the decisive factors in Pushkin's poetic and personal maturation away from his early naive Byronism. At the same time, Pushkin found in Shakespeare a release from the outworn conventions of French classical drama that had until then provided the precepts for writers for the Russian stage. For Pushkin, two specific features of Shakespearean drama were congenial: the abandonment of the three classical unities in favor of the primacy of character in dramatic action, and generic mixtures of comedy and tragedy, poetry and prose.