Effect of stand density and diversity on the tree ratio of height to diameter relationship in the park stands of southern Ukraine

Urban parks provide important ecological functions and are a factor in the well-being of urban residents. The article investigated the influence of factors on the dependence of tree height on tree diameter in a park stand. The role of community diversity as a factor that reduces the risk of tree damage was assessed. The role of tree damage, density, and stand diversity as predictors in the dependence of tree height on its diameter was revealed. The hypothesis of the scale dependence of the influence of stand density on plant growth was tested. The park inventory recorded morphometric data on 814 trees. The information collected was presented in a geographic information database. The number of plants that are within a radius of 3, 5, 7, 10 meters was determined for each of the recorded plant specimens. The diversity according Shannon of the plant community was estimated based on the information on the species composition of plants within a radius of 10 meters from the focal plant. The plant community in the park was represented by 27 species of trees and shrubs. The most frequent species was U. caprinifolia. The age of plants in the community was positively correlated with the diversity of vegetation in the surroundings of a particular plant. About 74.1% of the trees were found to have the signs of pathological damage. The best model to explain tree damage was a model that included as predictors plant species, its age, the diversity of the surrounding stand, and its density estimated from a 7-m radius sampling site. The GLM approach allowed to reveal that 83% of tree height variation can be explained by the information on tree and shrub species, plant condition (healthy plant or damaged one), its diameter and stand density. The stand density and the square of this index were found to be statistically significant predictors if the density was calculated for a sample area with a radius of 7 meters. A quadratic form of the dependence indicates the presence of the maximum of the function. The calculations showed that the first derivative of the quadratic function is equal to zero at a density of 9.3 individuals in a sample area with a radius of 7 meters, or 3.0 plants per 100 meters2

Acylated 2-(N-arylaminomethylene)benzo[b]thiophene-3(2H)-Ones: Molecular Switches with Varying Migrants and Substituents

Synthesis and properties of photochromic acylated 2-(N-arylaminomethylene)benzo[b]thiophene-3(2H)-ones are described. Their structure largely depends on the nature of acyl migrant and in a less degree on N-aryl substituent

Synthesis of Novel Iono- and Photochromic Spiropyrans Derived from 6,7-Dihydroxy-8-Formyl-4-Methyl-2H-Chromene-2-One

Novel photochromic spiropyrans (SPPs) containing 6′-hydroxy group were synthesized and their spectral properties as well as abilities for complexation with metal ions studied. In solutions they exist as equilibrium mixture of spirocyclic (A) and merocyanine (B) isomers. The largest content of merocyanine form was found for the derivative with an electron-donating methyl group in position 5 of hetaryl fragment. The irradiation of SPPs in acetonitrile shifts the equilibrium to the B form. Similar effect causes the addition of metal cations due to formation of colored complexes with merocyanine isomers

A Genome-Wide Analysis of Promoter-Mediated Phenotypic Noise in Escherichia coli

Gene expression is subject to random perturbations that lead to fluctuations in the rate of protein production. As a consequence, for any given protein, genetically identical organisms living in a constant environment will contain different amounts of that particular protein, resulting in different phenotypes. This phenomenon is known as “phenotypic noise.” In bacterial systems, previous studies have shown that, for specific genes, both transcriptional and translational processes affect phenotypic noise. Here, we focus on how the promoter regions of genes affect noise and ask whether levels of promoter-mediated noise are correlated with genes' functional attributes, using data for over 60% of all promoters in Escherichia coli. We find that essential genes and genes with a high degree of evolutionary conservation have promoters that confer low levels of noise. We also find that the level of noise cannot be attributed to the evolutionary time that different genes have spent in the genome of E. coli. In contrast to previous results in eukaryotes, we find no association between promoter-mediated noise and gene expression plasticity. These results are consistent with the hypothesis that, in bacteria, natural selection can act to reduce gene expression noise and that some of this noise is controlled through the sequence of the promoter region alon

Overview of mathematical approaches used to model bacterial chemotaxis I: the single cell

Mathematical modeling of bacterial chemotaxis systems has been influential and insightful in helping to understand experimental observations. We provide here a comprehensive overview of the range of mathematical approaches used for modeling, within a single bacterium, chemotactic processes caused by changes to external gradients in its environment. Specific areas of the bacterial system which have been studied and modeled are discussed in detail, including the modeling of adaptation in response to attractant gradients, the intracellular phosphorylation cascade, membrane receptor clustering, and spatial modeling of intracellular protein signal transduction. The importance of producing robust models that address adaptation, gain, and sensitivity are also discussed. This review highlights that while mathematical modeling has aided in understanding bacterial chemotaxis on the individual cell scale and guiding experimental design, no single model succeeds in robustly describing all of the basic elements of the cell. We conclude by discussing the importance of this and the future of modeling in this area

Menadione sodium bisulfite effect on growth performance and fatty acid profiles of geese muscle tissues

The specific effect of menadione sodium bisulfite (MSB, vicasol) on the content of specific fatty acids in skeletal muscle and muscular stomach of geese was established. MSB can stimulate the biosynthesis processes and catabolism of fatty acids depending on the period of the geese ontogenesis. Experimental use of MSB in skeletal muscle helps to increase the total content of unsaturated fatty acids (FA) primarily due to n-3 FAs. MSB increases the content of PUFA and SFA on the 35th day of ontogenesis, so the nutritional value of meat improves, and the resistance of myocyte membranes increases to oxidative damage. In the smooth muscle tissue of the goose stomach, the action of MSB revealed a higher content of UFA only on the 21st day of ontogenesis, due to PUFA, in particular, n-6 and MUFA. On the 28th day of ontogenesis, the content of PUFA increases due to n-3, with a decrease in the total content of UFA. At the end of the experiment, the UFA content decreases with increasing SFA. Reducton of the content of essential n-3, n-6, and UFA negatively affects the nutritional value of the product but increases the resistance of tissues to the active forms of oxygen. The use of MSB contributes to the overall increase of the average daily weight gain of geese from the 21st to the 28th day. The average body weight from the 21st to the 35th ontogenesis relative to the control group. We recommend using MSB at a dose of 0.7 mg/kg body weight for gosling feeding to increase the essential FA content in skeletal muscle tissue

Quantitative Modeling of Escherichia coli Chemotactic Motion in Environments Varying in Space and Time

Escherichia coli chemotactic motion in spatiotemporally varying environments is studied by using a computational model based on a coarse-grained description of the intracellular signaling pathway dynamics. We find that the cell's chemotaxis drift velocity vd is a constant in an exponential attractant concentration gradient [L]∝exp(Gx). vd depends linearly on the exponential gradient G before it saturates when G is larger than a critical value GC. We find that GC is determined by the intracellular adaptation rate kR with a simple scaling law: . The linear dependence of vd on G = d(ln[L])/dx directly demonstrates E. coli's ability in sensing the derivative of the logarithmic attractant concentration. The existence of the limiting gradient GC and its scaling with kR are explained by the underlying intracellular adaptation dynamics and the flagellar motor response characteristics. For individual cells, we find that the overall average run length in an exponential gradient is longer than that in a homogeneous environment, which is caused by the constant kinase activity shift (decrease). The forward runs (up the gradient) are longer than the backward runs, as expected; and depending on the exact gradient, the (shorter) backward runs can be comparable to runs in a spatially homogeneous environment, consistent with previous experiments. In (spatial) ligand gradients that also vary in time, the chemotaxis motion is damped as the frequency ω of the time-varying spatial gradient becomes faster than a critical value ωc, which is controlled by the cell's chemotaxis adaptation rate kR. Finally, our model, with no adjustable parameters, agrees quantitatively with the classical capillary assay experiments where the attractant concentration changes both in space and time. Our model can thus be used to study E. coli chemotaxis behavior in arbitrary spatiotemporally varying environments. Further experiments are suggested to test some of the model predictions

NGDEEP Epoch 1: Spatially Resolved Hα\alpha Observations of Disk and Bulge Growth in Star-Forming Galaxies at z∼z \sim 0.6-2.2 from JWST NIRISS Slitless Spectroscopy

We study the H$\alpha$ equivalent width, EW(H$\alpha$), maps of 19 galaxies at $0.6 < z < 2.2$ in the Hubble Ultra Deep Field (HUDF) derived from NIRISS slitless spectroscopy as part of the Next Generation Deep Extragalactic Exploratory Public (NGDEEP) Survey. Our galaxies mostly lie on the star-formation main sequence with a stellar mass range of $\mathrm{10^9 - 10^{11} M_\odot}$, and are therefore characteristic of "typical" star-forming galaxies at these redshifts. Leveraging deep HST and JWST broad-band images, spanning 0.4-4 $\mu$m, we perform spatially-resolved fitting of the spectral energy distributions (SEDs) for these galaxies and construct specific star formation rate (sSFR) and stellar-mass-weighted age maps. We compare these to the EW(H$\alpha$) maps with a spatial resolution of $\sim$1 kpc. The pixel-to-pixel EW(H$\alpha$) increases with increasing sSFR and with decreasing age, with the average trend slightly different from the relations derived from integrated fluxes of galaxies from the literature. Quantifying the radial profiles of EW(H$\alpha$), sSFR, and age, the majority (84%) of galaxies show positive EW(H$\alpha$) gradients, positive sSFR gradients, and negative age gradients, in line with the the inside-out quenching scenario. A few galaxies (16%) show inverse (and flat) trends possibly due to merging or starbursts. Comparing the distributions of EW(H$\alpha$) and sSFR to the star formation history models as a function of galactocentric radius, the central region of galaxies (e.g., their bulges) have experienced, at least one, rapid star-formation episodes, which leads to the formation of bulge, while their outer regions (e.g., disks) grow in a more steady-state. These results demonstrate the ability to study resolved star formation in distant galaxies with JWST NIRISS.Comment: 22 pages, 11 figure

Dependence of Bacterial Chemotaxis on Gradient Shape and Adaptation Rate

Simulation of cellular behavior on multiple scales requires models that are sufficiently detailed to capture central intracellular processes but at the same time enable the simulation of entire cell populations in a computationally cheap way. In this paper we present RapidCell, a hybrid model of chemotactic Escherichia coli that combines the Monod-Wyman-Changeux signal processing by mixed chemoreceptor clusters, the adaptation dynamics described by ordinary differential equations, and a detailed model of cell tumbling. Our model dramatically reduces computational costs and allows the highly efficient simulation of E. coli chemotaxis. We use the model to investigate chemotaxis in different gradients, and suggest a new, constant-activity type of gradient to systematically study chemotactic behavior of virtual bacteria. Using the unique properties of this gradient, we show that optimal chemotaxis is observed in a narrow range of CheA kinase activity, where concentration of the response regulator CheY-P falls into the operating range of flagellar motors. Our simulations also confirm that the CheB phosphorylation feedback improves chemotactic efficiency by shifting the average CheY-P concentration to fit the motor operating range. Our results suggest that in liquid media the variability in adaptation times among cells may be evolutionary favorable to ensure coexistence of subpopulations that will be optimally tactic in different gradients. However, in a porous medium (agar) such variability appears to be less important, because agar structure poses mainly negative selection against subpopulations with low levels of adaptation enzymes. RapidCell is available from the authors upon request