Light Distribution and Perceived Spaciousness: Light Patterns in Scale Models

Previous research showed that light distribution can affect the perception of spatial size and shape. However, most studies are limited to quantitative assessment of a few scenarios without explaining possible causes behind peoples’ experiences. This exploratory study aimed to reveal complex relationships between light patterns and perceived size, and to investigate how light patterns affect perceived spaciousness. A qualitative approach was used with pair-wise comparisons between systematic visual observations of scale models. The observations confirmed that illuminated walls increase spaciousness. Yet, darkness impacts the perception of spaciousness as well. Both compound and separated light zones can expand depth, height, or width, depending on the interpretation of these patterns of light seen in relation to the whole spatial context. Furthermore, the position of illuminated areas, with placements on edge or in the center, may additionally influence perceived size.

Constraints on the temperature-density relation of the intergalactic medium with non-negligible absorber spatial structure

We investigate evolution of physical parameters of the intergalactic medium using an analysis of Lya forest lines detected towards distant quasars. We used the enlarged sample of 98 quasars obtained with Keck/HIRES and VLT/UVES. We show that taking into account a finite spatial size of absorbers, regulated by pressure smoothing, significantly affects the inferred thermal parameters of the intergalactic gas, such as the hydrogen photoionization rate and parameters of the temperature-density relation. Using Bayesian framework we constrained for the first time the scale parameter between the Jeans length and characteristic size of the absorbers. We also discuss limitations of the method based on the analysis of the minimal broadending of Lya lines, which stem from the patchy nature of He II reionization.

Quantum halo states in two-dimensional dipolar clusters

A halo is an intrinsically quantum object defined as a bound state of a spatial size which extends deeply into the classically forbidden region. Previously, halos have been observed in bound states of two and less frequently of three atoms. Here, we propose a realization of halo states containing as many as six atoms. We report the binding energies, pair correlation functions, spatial distributions, and sizes of few-body clusters composed by bosonic dipolar atoms in a bilayer geometry. We find two very distinct halo structures, for large interlayer separation the halo structure is roughly symmetric and we discover an unusual highly anisotropic shape of halo states close to the unbinding threshold. Our results open avenues of using ultracold gases for the experimental realization of halos composed by atoms with dipolar interactions and containing as many as six atoms.

Localised labyrinthine patterns in ecosystems

Self-organisation is a ubiquitous phenomenon in ecosystems. These systems can experience transitions from a uniform cover towards the formation of vegetation patterns as a result of symmetry-breaking instability. They can be either periodic or localised in space. Localised vegetation patterns consist of more or less circular spots or patches that can be either isolated or randomly distributed in space. We report on a striking patterning phenomenon consisting of localised vegetation labyrinths. This intriguing pattern is visible in satellite photographs taken in many territories of Africa and Australia. They consist of labyrinths which is spatially irregular pattern surrounded by either a homogeneous cover or a bare soil. The phenomenon is not specific to particular plants or soils. They are observed on strictly homogenous environmental conditions on flat landscapes, but they are also visible on hills. The spatial size of localized labyrinth ranges typically from a few hundred meters to ten kilometres. A simple modelling approach based on the interplay between short-range and long-range interactions governing plant communities or on the water dynamics explains the observations reported here.

USE OF GIS TECHNOLOGIES FOR INVENTORY OF PROTECTED AREAS OF SYRIA

The article presents the result of using GIS for collecting, processing and storing distributed data on specially protected natural areas (SPNA) in the Syrian Arab Republic. The emergence of GIS, using a huge amount of data, has greatly simplified the process of studying protected areas, assessing their spatial size and geographical location, identifying their characteristics and processes of their development and structuring. With the advent of GIS, monitoring of such objects has become more accurate and flexible. This article describes the experience of using the freeware GIS for systematization of information about the protected areas of Syria. The procedure for creating a digital map of the protected areas of Syria is outlined, the main elements of its thematic content are described. The created digital map is an informational basis for the design and development of the monitoring system for the SPNA in Syria.

Aerodynamics of a wing under figure-of-eight flapping motion: FSI simulations

This paper investigates the aerodynamics of a wing under figure-of-eight flapping motion based on Fluid–Structure Interaction (FSI) Computational Fluid Dynamics (CFD) simulations. The kinematic of a wing under figure-of-eight motion creates a condition with a variable angle-of-attack. The effect of using different angles of attack at an initial condition, namely initial pitch angles, for the wing and the spatial size of the figure-of-eight pattern, namely the input link angle, is investigated. The initial pitch angles input is varied from 0° to 330° in steps of 30°, and the input link angles used are 30°, 45°, and 60°. The Young’s modulus of the wing is 3.4 GPa spanwise, which is the elastic modulus of balsa wood material. In comparison with an initial pitch angle of 0°, the 90° initial pitch angle shows much better flight performance in terms of lift generated and stability. The results show that the maximum average lift coefficient of 0.393 occurs at the 90° initial pitch angle. The maximum lift-induced moment for the 90° initial pitch angle is only 5.55% of the maximum lift induced moment for the 0° initial pitch angle. A higher input link angle generates a greater lift force. The pressure distribution in the vicinity of the wing area and the von Mises stress of the wing are also presented.

Application of Optimization Algorithms for Identification of Reference Points in a Monitoring Network

Geodetic measurements are commonly used in displacement analysis to determine the absolute values of displacements of points of interest. In order to properly determine the displacement values, it is necessary to correctly identify a subgroup of mutually stable points constituting a reference system. The complexity of this task depends on the spatial size of the network, the timespan of measurements and geological conditions affecting the type of changes in the location of points. As a consequence of the abovementioned factors, the task of stable identification in a longer timespan for a subgroup of points may produce equivocal results. In particular, it is likely that alternative subgroups of reference points meeting the mutual stability criteria will be selected, sometimes without common reference points. The proposed method of reference system identification utilises optimisation algorithms. Two such algorithms were tested, i.e., simulated annealing (SA) and Hooke-Jeeves (HJ) method. Two numerical examples were used to test the proposed method. Although in the first example both methods delivered a positive result, the second example showed the superiority of the SA method over the HJ. The proposed method can be considered a tool supporting the person analysing and making calculations in reaching the ultimate decision on reference points.

Structure–function relationship of terpenoid glycosyltransferases from plants

The spatial size of the catalytic centre and a large hydrophobic pocket in the active site affect the enzymatic activity and substrate preference of uridine diphosphate–sugar-dependent terpenoid glycosyltransferases in plants.