COVID-19: Exercise Behavior of College Students Communicating at Home

Background: During the outbreak and spread of COVID-19, the extension of college students' time spent studying at home changed their physical exercise behavior and affected the physical activity behavior of the whole family.Methods: A questionnaire survey was conducted among 1,582 college students using a specific measurement scale. A total of 305 urban college students were selected as research subjects. SPSS24.0 and AMOS24.0 were used for statistical analysis.Results: During the COVID-19 transmission period, the pair correlation coefficients of exercise behavior, exercise attitude, and family exercise conditions were 0.63, 0.36, and 0.25, respectively. The influence on family exercise behavior is as follows: college students' exercise behavior (0.403), family exercise support (0.329), and college students' exercise attitude (0.257). The most significant influence on family exercise support is college students' exercise attitude (0.509). The regression model of family exercise behavior standardization had 0.74 and 0.44 explanatory power to family exercise behavior and family exercise support, respectively.Conclusions: The individual-level interventions were assessed by considering the interaction between individual exercise behavior and individual factors. In addition, the exercise environment exhibited a regulatory role and should be controlled. At the interpersonal level, the communication of the college students regarding exercise behavior was bidirectional. Exercise support for family members is an important factor affecting two-way communication and has a significant effect. With the development of the exercise behavior theory, the interaction between individuals is the origin of the spread of group behavior. The data suggest that instead of one-way influence two-way influence mechanisms should be proposed to assess the transformation from the individual to group exercise behavior.

Structure-dynamics relationships in cryogenically deformed bulk metallic glass

The atomistic mechanisms occurring during the processes of aging and rejuvenation in glassy materials involve very small structural rearrangements that are extremely difficult to capture experimentally. Here we use in-situ X-ray diffraction to investigate the structural rearrangements during annealing from 77 K up to the crystallization temperature in Cu44Zr44Al8Hf2Co2 bulk metallic glass rejuvenated by high pressure torsion performed at cryogenic temperatures and at room temperature. Using a measure of the configurational entropy calculated from the X-ray pair correlation function, the structural footprint of the deformation-induced rejuvenation in bulk metallic glass is revealed. With synchrotron radiation, temperature and time resolutions comparable to calorimetric experiments are possible. This opens hitherto unavailable experimental possibilities allowing to unambiguously correlate changes in atomic configuration and structure to calorimetrically observed signals and can attribute those to changes of the dynamic and vibrational relaxations (α-, β- and γ-transition) in glassy materials. The results suggest that the structural footprint of the β-transition is related to entropic relaxation with characteristics of a first-order transition. Dynamic mechanical analysis data shows that in the range of the β-transition, non-reversible structural rearrangements are preferentially activated. The low-temperature γ-transition is mostly triggering reversible deformations and shows a change of slope in the entropic footprint suggesting second-order characteristics.

Social wasps repair emergent topological defects

Social insects have evolved a variety of architectural formations. Bees and wasps are well known for their ability to achieve compact structures by building hexagonal cells. Polistes wattii, an open nesting paper wasp species, builds planar hexagonal structures. Here, using the pair correlation function approach, we show that their nests exhibit short-range hexagonal order but no long-range order akin to amorphous materials. Hexagonal orientational order was well preserved globally. We also show the presence of emergent topological defects such as disclination pairs (pentagon-heptagon dipoles), Stone-Wales quadrupoles, and other higher-order defects and discuss how these defects were fixed in the nest, thereby restoring order. Furthermore, we suggest the possible role of such defects in shaping nesting architectures of other social insect species.

Signs of long-term adaptation and their relationship with the indicators of reproductive qualities in sows of the universal direction of productivity

The paper presents the results of the study of signs of long-term adaptation and indicators of reproductive qualities of sows of the universal direction of productivity, as well as calculates the economic efficiency of research results. The experimental part of the work was performed in the agricultural formations of the Dnipropetrovsk region and the laboratory of animal husbandry of the State Institution “Institute of Grain Crops of NAAS of Ukraine”. The work was performed in accordance with the research program № 31 “Genetic improvement of farm animals, their reproduction and conservation of biodiversity (Genetics, conservation, and reproduction of bioresources in animal husbandry)”, task – 31.02.01.18. pigs of different genotypes and to develop an integrated system for creating a highly productive population” (№ DR 0121U107903). Evaluation of sows on the indicators of long-term adaptation and reproductive qualities was carried out taking into account the following characteristics: life expectancy, months; duration of breeding use, months; farrowing was obtained; received piglets total, ch.; obtained live piglets, ch.; multiplicity, ch.; nest weight at the time of weaning at the age of 28 days, kg; safety of piglets before weaning, %. The index “level of adaptation” was calculated according to the method of Smirnov (2003), the index of reproductive qualities – according to the method of M. D. Berezovsky. Economic efficiency of research results and biometric processing of the obtained data were carried out according to generally accepted methods. It is established that sows of large white breeds of the controlled herd are characterized by rather high indicators of reproductive qualities and level of adaptation to conditions of intensive technology of operation. The life expectancy of sows in the main herd is 44.1 months, the duration of breeding use – 32.8 months, the index “level of adaptation” – 11.87 points. According to the indicators of fertility and nest weight at the time of weaning, the animals of the main herd belong to the first class and the elite class. Taking into account intra-breed differentiation according to the index “level of adaptation” sows of class M- significantly outperformed peers of class M+ in life expectancy by 54.77 %, duration of breeding use – by 71.48 %, index “level of adaptation” – by 66.09 %. Significant differences between groups of animals of these classes were found by multiplicity (td = 2.22; P < 0.05), nest weight at the time of weaning at the age of 28 days, kg (td = 2.56; P < 0.01) and index MD Berezovsky (td = 2.60; P < 0.01). The coefficients of pair correlation between traits that characterize the level of adaptation and reproductive qualities of sows range from -0.704 (tr = 10.80) to +0.982 (tr = 213.05). The use of sow class M- according to the index “level of adaptation” provides an increase in additional products at the level of +5.71 %, or 140.80 UAH. We propose to select repair young stock from sows of the leading group with the index “level of adaptation” of 6.55–8.08 points in the conditions of breeding plants and breeders, as well as industrial complexes.

Mapping the Intensity Function of a Non-stationary Point Process in Unobserved Areas

Seismic networks provide data that are used as basis both for public safety decisions and for scientific research. Their configuration affects the data completeness, which in turn, critically affects several seismological scientific targets (e.g., earthquake prediction, seismic hazard...). In this context, a key aspect is how to map earthquakes density in seismogenic areas from censored data or even in areas that are not covered by the network. We propose to predict the spatial distribution of earthquakes from the knowledge of presence locations and geological relationships, taking into account any interactions between records. Namely, in a more general setting, we aim to estimate the intensity function of a point process, conditional to its censored realization, as in geostatistics for continuous processes. We define a predictor as the best linear unbiased combination of the observed point pattern. We show that the weight function associated to the predictor is the solution of a Fredholm equation of second kind. Both the kernel and the source term of the Fredholm equation are related to the first- and second-order characteristics of the point process through the intensity and the pair correlation function. Results are presented and illustrated on simulated non-stationary point processes and real data for mapping Greek Hellenic seismicity in a region with unreliable and incomplete records.

Synthesis of Colloidal Silver Using Lignosulfonates

Colloidal silver solutions can be used as catalysts for carrying out various chemical transformations of organic substances and solving the problems of disposal of toxic compounds, as well as antibacterial agents for combating pathogenic microflora, in the manufacture of lubricants and light-absorbing materials, coatings, sensors, conductive pastes, and high-performance electrode materials. The research purpose is to study the synthesis of colloidal silver using a solution of technical lignosulfonates (LST) as a stabilizer. Colloidal silver was synthesized as a result of the reduction-oxidation (redox) reaction of Ag(I) cations with glucose at 100 °C in the presence of lignosulfonates. The reaction was carried out in an alkaline medium, which is provided by the addition of ammonia water. Electronic spectroscopy was used to control the synthesis of colloidal silver. After the reaction, the solution turned dark brown and an intense absorption band with a maximum at 400 nm appeared on the electron spectra. The effects of reagent consumption and synthesis duration were studied. It was found that the optimal reagent consumption in the colloidal silver synthesis is as follows: 2.5–5 g glucose / g Ag, 0.3–1 g LST / g Ag, and 3–5 g NH3 / g Ag. The synthesis duration is 2–5 min. The resulting colloidal silver solution is stable for several months. Partial stratification without precipitation is observed during the solution storage. It is shown experimentally that the stratification is followed by a redistribution of colloidal silver particles. Electron spectroscopy confirmed the absence of colloidal silver particles in the upper layer. The reaction kinetics has been studied in experiments carried out under thermostatically controlled conditions at temperatures from 50 to 100 °C. The kinetic dependence is described by a first-order equation at the initial stage of the reaction, the duration of which depends on the temperature. The duration of the active part of the kinetic curves is 15–90 % of the total reaction time. The logarithm of the rate constant on the active section was proved to depend linearly on the reverse thermodynamic temperature (pair correlation coefficient is 0.9887). The activation energy was 47 kJ/mol. For citation: Plakhin V.A., Khabarov Yu.G., Veshnyakov V.A. Synthesis of Colloidal Silver Using Lignosulfonates. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 6, pp. 184–195. DOI: 10.37482/0536-1036-2021-6-184-195

In vivo pair correlation microscopy reveals dengue virus capsid protein nucleocytoplasmic bidirectional movement in mammalian infected cells

Flaviviruses are major human disease-causing pathogens, including dengue virus (DENV), Zika virus, yellow fever virus and others. DENV infects hundreds of millions of people per year around the world, causing a tremendous social and economic burden. DENV capsid (C) protein plays an essential role during genome encapsidation and viral particle formation. It has been previously shown that DENV C enters the nucleus in infected cells. However, whether DENV C protein exhibits nuclear export remains unclear. By spatially cross-correlating different regions of the cell, we investigated DENV C movement across the nuclear envelope during the infection cycle. We observed that transport takes place in both directions and with similar translocation times (in the ms time scale) suggesting a bidirectional movement of both C protein import and export.Furthermore, from the pair cross-correlation functions in cytoplasmic or nuclear regions we found two populations of C molecules in each compartment with fast and slow mobilities. While in the cytoplasm the correlation times were in the 2–6 and 40–110 ms range for the fast and slow mobility populations respectively, in the cell nucleus they were 1–10 and 25–140 ms range, respectively. The fast mobility of DENV C in cytoplasmic and nuclear regions agreed with the diffusion coefficients from Brownian motion previously reported from correlation analysis. These studies provide the first evidence of DENV C shuttling from and to the nucleus in infected cells, opening new venues for antiviral interventions.

Spatial distribution patterns of Afzelia africana (Fabaceae – Detarioideae) in a tropical savanna of Benin: implications for management

Background and aims – Understanding the spatial patterns and associations of tree species with their conspecific and heterospecific neighbours is critical for sustainable management of their stands. This study assessed the intra- and interspecific spatial structure of six life stages in Afzelia africana, a keystone multipurpose and endangered tree species in a tropical savanna of Benin.Material and methods – Three plots of 4 ha each were demarcated on three sites along a conservation gradient (hunting zone – core conservation zone). Individuals of A. africana (irrespective of their diameter at breast height) and heterospecific trees (dbh ≥ 5 cm) were mapped. Tree spatial patterns and associations were determined using univariate and bivariate pair correlation functions. The distance to the nearest neighbour was further used to assess tree-to-tree distance.Key results – We found variable spatial patterns across sites. In the core zone where wildlife density is high, most life stages had a random distribution. In contrast, in the hunting zone where wildlife density is low, the species spatial distribution changed from a predominantly aggregative pattern during early stages to a less aggregative or random spatial pattern for very large adults. Most pairs of life stages showed neutral associations, except for small and large adults, which had positive association between themselves on two sites. We also found that A. africana tree spatial distribution was unrelated to heterospecific trees.Conclusion – We suggest that bush fire, seed dispersion, predation, and local environment would have contributed to the observed patterns.

Efficient Cross-Correlation Filtering of One- and Two-Color Single Molecule Localization Microscopy Data

Single molecule localization microscopy has become a prominent technique to quantitatively study biological processes below the optical diffraction limit. By fitting the intensity profile of single sparsely activated fluorophores, which are often attached to a specific biomolecule within a cell, the locations of all imaged fluorophores are obtained with ∼20 nm resolution in the form of a coordinate table. While rendered super-resolution images reveal structural features of intracellular structures below the optical diffraction limit, the ability to further analyze the molecular coordinates presents opportunities to gain additional quantitative insights into the spatial distribution of a biomolecule of interest. For instance, pair-correlation or radial distribution functions are employed as a measure of clustering, and cross-correlation analysis reveals the colocalization of two biomolecules in two-color SMLM data. Here, we present an efficient filtering method for SMLM data sets based on pair- or cross-correlation to isolate localizations that are clustered or appear in proximity to a second set of localizations in two-color SMLM data. In this way, clustered or colocalized localizations can be separately rendered and analyzed to compare other molecular properties to the remaining localizations, such as their oligomeric state or mobility in live cell experiments. Current matrix-based cross-correlation analyses of large data sets quickly reach the limitations of computer memory due to the space complexity of constructing the distance matrices. Our approach leverages k-dimensional trees to efficiently perform range searches, which dramatically reduces memory needs and the time for the analysis. We demonstrate the versatile applications of this method with simulated data sets as well as examples of two-color SMLM data. The provided MATLAB code and its description can be integrated into existing localization analysis packages and provides a useful resource to analyze SMLM data with new detail.