Noise reduction in 3D noncollinear parametric amplifier

We analytically find an approximate Bloch-Messiah reduction of a noncollinear parametric amplifier pumped with a focused monochromatic beam. We consider type I phase matching. The results are obtained using a perturbative expansion and scaled to a high gain regime. They allow a straightforward maximization of the signal gain and minimization of the parametric fluorescence noise. We find the fundamental mode of the amplifier, which is an elliptic Gaussian defining the optimal seed beam shape. We conclude that the output of the amplifier should be stripped of higher order modes, which are approximately Hermite-Gaussian beams. Alternatively, the pump waist can be adjusted such that the amount of noise produced in the higher order modes is minimized.Comment: 18 pages, 9 figures, accepted to Applied Physics

Bioaccumulation and Toxicity of Organic Chemicals in Terrestrial Invertebrates

Terrestrial invertebrates are key components in ecosystems, with crucial roles in soil structure, functioning, and ecosystem services. The present chapter covers how terrestrial invertebrates are impacted by organic chemicals, focusing on up-to-date information regarding bioavailability, exposure routes and general concepts on bioaccumulation, toxicity, and existing models. Terrestrial invertebrates are exposed to organic chemicals through different routes, which are dependent on both the organismal traits and nature of exposure, including chemical properties and media characteristics. Bioaccumulation and toxicity data for several groups of organic chemicals are presented and discussed, attempting to cover plant protection products (herbicides, insecticides, fungicides, and molluscicides), veterinary and human pharmaceuticals, polycyclic aromatic compounds, polychlorinated biphenyls, flame retardants, and personal care products. Chemical mixtures are also discussed bearing in mind that chemicals appear simultaneously in the environment. The biomagnification of organic chemicals is considered in light of the consumption of terrestrial invertebrates as novel feed and food sources. This chapter highlights how science has contributed with data from the last 5 years, providing evidence on bioavailability, bioaccumulation, and toxicity derived from exposure to organic chemicals, including insights into the main challenges and shortcomings to extrapolate results to real exposure scenarios

The Polish school – quo vadis?

Polska szkoła ulega ciągłym przemianom. Wdrażane są kolejne reformy edukacji w różnym stopniu wpływające na kształt polskiego szkolnictwa, programy i stosowane metody nauczania. Można często odnieść wrażenie, że reforma goni reformę, a wpływ wprowadzanych zmian na poziom edukacji ma drugorzędne znaczenie. W artykule podjęto próbę oszacowania wpływu dwóch ostatnich reform na stan edukacji chemicznej w naszym kraju. Dodatkowo poddano analizie wpływ reform na popularność chemii jako przedmiotu w szkole ponadgimnazjalnej oraz jako kierunku studiów wyższych.The Polish school is subject to continuing changes. A series of educational reforms have been implemented which have affected in varying degrees the shape of the Polish school system, programmes and applied teaching methods. One can often be under the impression that reform is chasing after reform and the impact of the introduced changes on the level of education is of secondary importance. In this paper an attempt has been made to estimate the impact of the two latest reforms on the level of teaching chemistry. In addition, the paper presents the analysis of the impact of these reforms on the popularity of chemistry as a secondary school subject and as a discipline in higher education

Filling the production gap in the Polish chemical industry – industrial scale production of acrylic acid and acrylates

Opisano opracowaną w Instytucie Chemii Przemysłowej (IChP), kompleksową technologię otrzymywania kwasu akrylowego (w tym z gliceryny) i estrów akrylowych. Technologia ta stanowi propozycję wypełnienia luki wytwórczej w obszarze syntezy wysokomarżowych akrylanów i półproduktów. Analiza ekonomiczna oraz analiza rynku surowcowego w odniesieniu do ww. technologii potwierdzają elastyczność opracowanego kompleksu wytwórczego, a także jego atrakcyjność w skali przemysłowej w porównaniu z działającymi instalacjami i rozwijanymi konkurencyjnymi technologiami. Innowacyjne rozwiązania, zaimplementowane w technologii, omówiono na przykładzie wybranych węzłów procesowych.A comprehensive technology for the synthesis of acrylic acid and acrylic esters obtained, among others, from glycerol and developed at the Industrial Chemistry Research Institute has been presented. It is expected that the proposed technology will go along way in filling the technological gap in the production of high-end acrylates as well as the by-products obtained during the process of their production. Analysis of data on the availability of raw materials to feed the technology confirms its flexibility for the production of acrylates for different markets and situations. An economic analysis of existing industrial plants confirms the advantages of the proposed technology in methodology and economic viability. Selected innovative solutions presented in the technology have been discussed on the basis of specific process units

Community Detection in Quantum Complex Networks

Determining community structure is a central topic in the study of complex networks, be it technological, social, biological or chemical, in static or interacting systems. In this paper, we extend the concept of community detection from classical to quantum systems---a crucial missing component of a theory of complex networks based on quantum mechanics. We demonstrate that certain quantum mechanical effects cannot be captured using current classical complex network tools and provide new methods that overcome these problems. Our approaches are based on defining closeness measures between nodes, and then maximizing modularity with hierarchical clustering. Our closeness functions are based on quantum transport probability and state fidelity, two important quantities in quantum information theory. To illustrate the effectiveness of our approach in detecting community structure in quantum systems, we provide several examples, including a naturally occurring light-harvesting complex, LHCII. The prediction of our simplest algorithm, semiclassical in nature, mostly agrees with a proposed partitioning for the LHCII found in quantum chemistry literature, whereas our fully quantum treatment of the problem uncovers a new, consistent, and appropriately quantum community structure

Degree Distribution in Quantum Walks on Complex Networks

In this theoretical study, we analyze quantum walks on complex networks, which model network-based processes ranging from quantum computing to biology and even sociology. Specifically, we analytically relate the average long time probability distribution for the location of a unitary quantum walker to that of a corresponding classical walker. The distribution of the classical walker is proportional to the distribution of degrees, which measures the connectivity of the network nodes and underlies many methods for analyzing classical networks including website ranking. The quantum distribution becomes exactly equal to the classical distribution when the walk has zero energy and at higher energies the difference, the so-called quantumness, is bounded by the energy of the initial state. We give an example for which the quantumness equals a Renyi entropy of the normalized weighted degrees, guiding us to regimes for which the classical degree-dependent result is recovered and others for which quantum effects dominate