Optimal paths on the road network as directed polymers

We analyze the statistics of the shortest and fastest paths on the road network between randomly sampled end points. To a good approximation, these optimal paths are found to be directed in that their lengths (at large scales) are linearly proportional to the absolute distance between them. This motivates comparisons to universal features of directed polymers in random media. There are similarities in scalings of fluctuations in length/time and transverse wanderings, but also important distinctions in the scaling exponents, likely due to long-range correlations in geographic and man-made features. At short scales the optimal paths are not directed due to circuitous excursions governed by a fat-tailed (power-law) probability distribution.Comment: 5 pages, 7 figure

Comment on ``Conduction states in oxide perovskites: Three manifestations of Ti3+^{3 +} Jahn-Teller polarons in barium titanate''

In this comment to [S. Lenjer, O. F. Schirmer, H. Hesse, and Th. W. Kool, Phys. Rev. B {\bf 66}, 165106 (2002)] we discuss the electronic structure of oxygen vacancies in perovskites. First principles computations are in favour of rather deep levels in these vacancies, and Lenjer et al suggest that the electrons' interaction energy is negative, but data on electroconductivity are against.Comment: 2 pages, no figure

Fast and accurate semantic annotation of bioassays exploiting a hybrid of machine learning and user confirmation

Bioinformatics and computer aided drug design rely on the curation of a large number of protocols for biological assays that measure the ability of potential drugs to achieve a therapeutic effect. These assay protocols are generally published by scientists in the form of plain text, which needs to be more precisely annotated in order to be useful to software methods. We have developed a pragmatic approach to describing assays according to the semantic definitions of the BioAssay Ontology (BAO) project, using a hybrid of machine learning based on natural language processing, and a simplified user interface designed to help scientists curate their data with minimum effort. We have carried out this work based on the premise that pure machine learning is insufficiently accurate, and that expecting scientists to find the time to annotate their protocols manually is unrealistic. By combining these approaches, we have created an effective prototype for which annotation of bioassay text within the domain of the training set can be accomplished very quickly. Well-trained annotations require single-click user approval, while annotations from outside the training set domain can be identified using the search feature of a well-designed user interface, and subsequently used to improve the underlying models. By drastically reducing the time required for scientists to annotate their assays, we can realistically advocate for semantic annotation to become a standard part of the publication process. Once even a small proportion of the public body of bioassay data is marked up, bioinformatics researchers can begin to construct sophisticated and useful searching and analysis algorithms that will provide a diverse and powerful set of tools for drug discovery researchers

Methods of estimation of dissipative properties of steels at low temperatures

Use of the methodology of multifractal parameterization of structures, for conducting an estimate of habits of change in micromechanisms of shattering of steel at different temperatures of the testings, reflecting to dynamic loudspeaker of the latent dissipative processes. This method allows to present quantitatively not only an over-all configuration of structure for actual natural materials, but also inhomogeneity of allocation geometrical, physical, chemical, etc. characteristics, according to the nature of investigated structure that cannot be reached ordinary methods

Digital agriculture informational resources in local and international databases

The article reviews informational resources on precision and digital agriculture in international cross-disciplinal and sectoral international and local databases. The databases Web of Science, Scopus, AGRIS (by FAO UN) and Engineering infrastructure of Agriculture, Rosinformagrotech, AGROS (by Central Scientific Agricultural Library) with the retrieval requests “Digital agriculture”, “Precision Agriculture” were analyzed. The authors estimated the dynamics of document flows to the AGROS database and confirmed strong growth of volume of local publications on precision agriculture to the level demonstrating technology adoption of precision agriculture. Meanwhile the level of document flow on digital agriculture is at the starting level. Analysis of most frequent publications on the topic showed that there’s no local specialized journals on precision agriculture, most frequently publications appeared in local journals such as “Machinery and equipment for rural areas”, “Soil science and agrochemistry”, “Agricultural machinery and technology”. Predominantly materials were published in specialized foreign journals “Computers and electronics in agriculture” and “Precision agriculture”. Most of the documents were obtained from WOS and Scopus databases, but a lot of them are irrelevant. While searching for foreign documents it makes sense to use all the databases available, but most of the full-size texts in open access are available in the AGRIS database. In the same way AGROS database provide a wide range of full-size texts in the Russian language. Both AGROS and AGRIS databases showed high efficiency of search with most relevant documents in search results since both databases use thesaurus as a linguistic tool

Giant piezoelectric response in textured piezoceramics with tetragonal tungsten bronze structure

This work was supported by the Ministry of Education and Science of the Russian Federation (research projects No. 3.1649.2017/4.6 and № 3.6439.2017)

Model predictive control and dynamic operability studies in a stirred tank: rapid temperature cycling for crystallization

A stirred-tank reactor was built with the objective of rapid and accurate temperature control in the reaction vessel. A first-principles heat transfer model was developed for the jacketed batch system, with the jacket inlet temperature used to control the vessel temperature. A model predictive controller was implemented to follow a rapidly changing temperature profile that cycled between steep heating and cooling motifs, and was tested experimentally at progressively shorter temperature cycles. For a water-solvent-water-jacket system, a cycle consisting of increasing and decreasing the temperature by 15°C over a period of 20 minutes was achieved in practice. The performance of the MPC controller was explained by calculating the dynamic operability characteristics of the process

Risk of Brain Tumors in Children and Susceptibility to Organophosphorus Insecticides: The Potential Role of Paraoxonase (PON1)

Prior research suggests that childhood brain tumors (CBTs) may be associated with exposure to pesticides. Organophosphorus insecticides (OPs) target the developing nervous system, and until recently, the most common residential insecticides were chlorpyrifos and diazinon, two OPs metabolized in the body through the cytochrome P450/paraoxonase 1 (PON1) pathway. To investigate whether two common PON1 polymorphisms, C-108T and Q192R, are associated with CBT occurrence, we conducted a population-based study of 66 cases and 236 controls using DNA from neonatal screening archive specimens in Washington State, linked to interview data. The risk of CBT was nonsignificantly increased in relation to the inefficient PON1 promoter allele [per PON1(-108T) allele, relative to PON1(-108CC): odds ratio (OR) = 1.4; 95% confidence interval (CI), 1.0–2.2; p-value for trend = 0.07]. Notably, this association was strongest and statistically significant among children whose mothers reported chemical treatment of the home for pests during pregnancy or childhood (per PON1(-108T) allele: among exposed, OR = 2.6; 95% CI, 1.2–5.5; among unexposed, OR = 0.9; 95% CI, 0.5–1.6) and for primitive neuroectodermal tumors (per PON1(-108T) allele: OR = 2.4; 95% CI, 1.1–5.4). The Q192R polymorphism, which alters the structure of PON1 and influences enzyme activity in a substrate-dependent manner, was not associated with CBT risk, nor was the PON1(C-108T/Q192R) haplotype. These results are consistent with an inverse association between PON1 levels and CBT occurrence, perhaps because of PON1’s ability to detoxify OPs common in children’s environments. Larger studies that measure plasma PON1 levels and incorporate more accurate estimates of pesticide exposure will be required to confirm these observations