Genetic diversity of sessile oak populations in the Czech Republic

The sessile oak is a broadleaved tree species of great ecological and silvicultural importance. Oaks are the second most widespread deciduous tree species in the Czech Republic, and ongoing climate change negatively affects the abundant and often monocultural Norway spruce. Therefore, a proportional increase of more resilient tree species such as sessile oak has emerged. This study aimed to depict population genetic diversity when analysing 272 individuals from 10 subpopulations selected across the Czech Republic. Targeted populations were chosen based on the minimal expected human impact on the stand (presumably autochthonous stands). All individuals were genotyped using 18 polymorphic microsatellite markers (SSRs) assembled into two amplification multiplexes. The high discriminatory power of SSR markers was tested and confirmed by the probability of identity analysis. The genetic differentiation of the subpopulations was low yet significant, quantified by Wright’s F-statistics within the range from 0.012 to 0.029. Based on discriminant analysis of principal components (DAPC), we detected two populations with geographic genetic correlation (the 15^th meridian east being a north-south boundary line) and one with a distinct genetic pattern. We assume that the population might previously be established from seed sources outside the Czech Republic. Moreover, to some extent, our findings advocate the legitimacy of the legislative rules for forest reproductive material (FRM) transfer.

Mechanical Properties Evaluation and Crack Propagation Behavior in Dissimilar Metal Welded Joints of 304 L Austenitic Stainless Steel and SA508 Low-Alloy Steel

The material mechanical properties and crack propagation behavior of dissimilar metal welded joint (DMWJ) of pressurized water reactor (PWR) was investigated. In this research, the mechanical parameters of the cladding layer materials (304L-SA508) of the DMWJ in PWRs were obtained by the continuous indentation test. Simultaneously, the user-defined (USDFLD) subroutine in ABAQUS was used to establish the heterogeneous materials model of the welded joint. On this basis, the local crack propagation path of DMWJs has been discussed based on the extended finite element method (XFEM). The result indicated that the strength value at the fusion boundary line (FB line) is the largest, and the yield strength reaches 689 MPa. The yield stress values of the cladding metal (304 L) and base metal (SA508) are 371 MPa and 501 MPa, respectively. Affected by the material constraint effect of the DMWJ, the crack will propagate through the FB line when the initial crack is perpendicular to the FB line. And when the initial crack parallels the FB line, the crack will deviate from it. Meanwhile, the crack propagation length is smaller as the initial crack tip is closer to the FB line when the load condition is constant.

Native Forests Show Resilience to Selective Timber Harvesting in Southeast Queensland, Australia

There is little published information on effects of management on the structure of mixed species forests in Queensland, Australia. We used long-term growth, abundance and dimension data from permanent plots to test the hypothesis that harvesting would reduce numbers of large trees and growth increments, while increasing recruitment. This hypothesis is key to policy and management decisions for forests covering about 9.5 million hectares. Inclusion of data on changes in forest structure (e.g., tree diameter, stem density) helps in assessment of forest suitability as habitat for a range of species. Growth rate (basal area) varied widely among forest types. Growth of each of four key species (i.e., Eucalyptus pilularis, Corymbia citriodora ssp. variegata, Callitris glaucophylla, and Eucalyptus crebra) reflected variation in rainfall across the study region. Callitris glaucophylla, a native conifer, is dominant when rainfall is < 600 mm per year. Corymbia citriodora ssp. variegata grows across much wider ranges in rainfall (600–1,200 mm year–1) at rates similar to Callitris glaucophylla. Historic harvesting increased recruitment and also increased the symmetry of diameter distributions. Harvesting has not reduced the current density of larger trees (diameter at breast height, DBH ≥ 60 cm) at a regional scale. Stand growth was unaffected by management principally owing to an increase in the density of trees of smaller diameter (10–20 cm DBH). Self-thinning limits potential stocking and we tested 3 methods for predicting self-thinning across forest types. We found that the slope of self-thinning lines under drier conditions is mostly < –2, suggesting highly dynamic self-thinning. Using a species-boundary line approach, growth is predicted to slow when basal areas reach around 66.1 m2 ha–1 in E. pilularis, 19.0 m2 ha–1 in C. citriodora ssp. variegata, 16.5 m2 ha–1 in Callitris glaucophylla, and 14.2 m2 ha–1 in E. crebra. The slope of the self-thinning line for E. pilularis was –1.662, similar to Reineke’s Stand Density Index (slope –1.605). To date, there is little evidence that selective harvesting and thinning have had negative impacts on rates of growth, on timber production, carbon sequestration or on aspects of forest structure regarded as important for biodiversity.

Quantum properties near the instability boundary in optomechanical system

The properties of the system near the instability boundary are very sensitive to external disturbances, which is important for amplifying some physical effects or improving the sensing accuracy. In this paper, the quantum properties near the instability boundary in a simple optomechanical system has been studied by numerical simulations. Calculations show that the transitional region connecting the Gaussian states and the Ring states when crossing the boundary is sometimes different from the region centered on the boundary line, but it is more essential. The change of the mechanical Wigner function in the transitional region directly reflects its bifurcation behavior in classical dynamics. Besides, quantum properties such as mechanical second-order coherence function and optomechanical entanglement, can be used to judge the corresponding bifurcation types and estimate the parameter width and position of the transitional region. The non-Gaussian transitional states exhibit strong entanglement robustness, and the transitional region as a boundary ribbon can be expected to replace the original classical instability boundary line in future applications.

Thermodynamic Analysis of Air-Blown Staged Gasification of Coal in a Flow

One of the ways to environmentally friendly use coal is an integrated gasification combined cycle. The most common oxidizing agent employed in gasification is oxygen. It is feasible to use air instead of oxygen to reduce the cost of generated electricity. The air gasification downsides can be reduced by using heated air and organizing a staged process. The paper is concerned with a thermodynamic analysis of the MHPS (Mitsubishi Hitachi Power Systems) air-blown staged gasifier. The analysis relies on an original approach that suggests investigating experimental data on a set of calculated ones. The experimental run nears the thermodynamic optimum, which coincides with the carbon boundary line. Cold gas efficiency can be increased from 78.6 to 81.5% by reducing the equivalence ratio. Thus, the temperature will decrease from 1 200 to 1 100 °C. The experimental run of the MHPS gasifier is not optimal thermodynamically, but it is probably optimal kinetically. The fact is that the rates of heterophase reactions decline near the carbon boundary, which leads to a sharp increase in fuel underburning and a decrease in efficiency. The experimental run is also located close to the region with the maximum thermal efficiency of the process, which is indicative of the high efficiency of converting air heat into chemical energy of producer gas.

Desert Climate Regionalization for Joshua Tree National Park and Surrounding Areas Using New Climate Network Observations

A new amalgamation of weather stations in and around Joshua Tree National Park in southeastern California, USA has allowed for objective climate analysis regionalization at a much finer scale than past studies. First, it sets a baseline for many regions within the park’s boundaries which were not subject to direct observations. Second these new observations are key to understanding shifting microclimate regimes in a desert ecosystem prone to the effects of climate change. Principal component analysis was used to regionalize the climate network based on monthly temperature and precipitation climate observations and standardized anomalies. Both the observation values and standardized climate anomalies identified regional boundaries. In general, these boundaries align with traditional ideas and past studies of the Mojave and Sonoran Deserts based on elevation (specifically the 1000m contour) for the National Park. Standardized anomaly values identified a boundary based on seasonal precipitation, while observation values identified a boundary based on elevation. The boundary line within the park is similar for both data approaches, with the boundary running along the higher western third of the park. Conversely, the two methods differ significantly in the Coachella Valley, where low elevations and low precipitation meets winter dominated seasonal precipitation. This study highlights the importance and opportunity of field observations to create climatological and ecological regionalization, as well as constructs a baseline to monitor and manage shifting desert regions in the future.

The Agreement between Greece and Italy on the Delimitation of their Respective Maritime Zones: An Italian Perspective

In 2020 Greece and Italy concluded a maritime delimitation agreement, extending the already-established boundary line between their respective continental shelf areas to the other maritime areas to which they are entitled under international law. The Greek authorities hailed the agreement as a great success, stressing that it fully reflects their position vis-à-vis maritime delimitation in the Mediterranean and it meets their national interests in the Ionian Sea. This article critically analyzes the agreement, in the light of various recent events, and it finds that it serves Italian interests too. In particular, the 2020 Italo-Greek agreement furthers Italy’s growing interest in delimiting the maritime zones to which it is entitled under international law, so as to prevent its rights and jurisdiction over them being impaired by the proclamation of overlapping zones by its neighbours. It also sets the stage for future proclamation by Italy of an EEZ covering the waters adjacent to its territorial sea in the Ionian Sea.

Detection of oscillatory solutions in a vacuum diode with total electron reflection

Stability features of steady-state solutions for a vacuum diode with complete deceleration of electron beam is studied. A boundary line on the (inter-electrode gap, external voltage)-plane separating stable solutions from unstable ones is built up. An instability development is shown to end in a state with non-linear oscillations of the electric field but with no virtual cathode in a plasma. Existence of non-linear oscillations of the electric field in a vacuum diode with total reflection of an electron beam points out that such a diode can be a basis to create microwave generator.

An optimal method of distribution of the slip zone on thrust bearing surfaces

Research to achieve a reasonable distribution of the slip zone of the sliding pair for better improvement of the hydrodynamic pressure of the liquid film is an intractable topic. To solve this issue, this paper takes the thrust bearing as the research object, and proposes to use the position number of the grid nodes at the boundary line between the slip and no-slip zone in each radial zone of the inclined pad to be variables. The variables are then defined as chromosomes in an adaptive genetic algorithm (AGA) and used to optimize the bearing capacity of the tilting pad. The results show that the optimal method of the AGA, which has good stability and repeatability, remarkably improves the distribution of the slip zone on the surface of the inclined pad. Therefore, the bearing capacity of the liquid film is significantly improved. Particularly, by using the optimization, the boundary line between the slip/no-slip zone is a composite form of a part of an arc and a part of the whisker. When the liquid flow through the heterogeneous slip/on-slip surfaces is used by this composite splicing method, the liquid pressure is upgraded in two steps. This is more conducive to increasing the pressure on multiple areas on the surface of the tilting pad, thereby achieving higher bearing capacity.

Determine the Land-Use Land-Cover Changes, Urban Expansion and Their Driving Factors for Sustainable Development in Gazipur Bangladesh

At present, urbanization is a very common phenomenon around the world, especially in developing countries, and has a significant impact on the land-use/land-cover of specific areas, producing some unwanted effects. Bangladesh is a tightly inhabited country whose urban population is increasing every day due to the expansion of infrastructure and industry. This study explores the land-use/land-cover change detection and urban dynamics of Gazipur district, Bangladesh, a newly developed industrial hub and city corporation, by using satellite imagery covering every 10-year interval over the period from 1990 to 2020. Supervised classification with a maximum likelihood classifier was used to gather spatial and temporal information from Landsat 5 (TM), 7 (ETM+) and 8 (OLI/TIRS) images. The Geographical Information System (GIS) methodology was also employed to detect changes over time. The kappa coefficient ranged between 0.75 and 0.90. The agricultural land was observed to be shrinking very rapidly, with an area of 716 km2 in 2020. Urbanization increased rapidly in this area, and the urban area grew by more than 500% during the study period. The urbanized area expanded along major roads such as the Dhaka–Mymensingh Highway and Dhaka bypass road. The urbanized area was, moreover, concentrated near the boundary line of Dhaka, the capital city of Bangladesh. Urban expansion was found to be influenced by demographic-, economic-, location- and accessibility-related factors. Therefore, similarly to many countries, concrete urban and development policies should be formulated to preserve the environment and, thereby, achieve sustainable development goal (SDG) 11 (sustainable cities and communities).