scholarly journals Impact of brush fire and pinetum horizontal structure on the tree condition

Author(s):  
A A Vais ◽  
S L Shevelev ◽  
V N Nemich
2013 ◽  
Vol 62 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Maria Mrówczyńska

Abstract The paper attempts to determine an optimum structure of a directional measurement and control network intended for investigating horizontal displacements. For this purpose it uses the notion of entropy as a logarithmical measure of probability of the state of a particular observation system. An optimum number of observations results from the difference of the entropy of the vector of parameters ΔHX̂ (x)corresponding to one extra observation. An increment of entropy interpreted as an increment of the amount of information about the state of the system determines the adoption or rejection of another extra observation to be carried out.


Author(s):  
Bugero N.V. ◽  
Ilyina N.A. ◽  
Aleksandrova S.M.

In order to understand the structure and dynamics of symbiotic relationships of human intestinal biotope micro-organisms, taxonomic constancy indices, the degree of contagion of the biocenosis under study and floristic significance were investigated, which made it possible to detect qualitative and quantitative changes in the microecology of the biotope being studied in persons living in different ecologically heterogeneous territories of Saint Petersburg. The contagiosity index estimated the distribution of species in space. Persons living in the ecologically disadvantaged Kirov district of the city have been found to show a reliable increase in this indicator for the obligate microflora: bifido and lacto bacteria, intestinal columns and bacteroids, compared to the resort district, which is considered a relatively favourable area for residence. On the contrary, there has been a reliable decrease in this indicator in the group of opportunistic micro-organisms (fungi of the genus Candida, staphylococcus, clostridium, etc.), resulting in the liberation of ecological niches successfully occupied by transient flora. This ratio reveals an imbalance of participation in the horizontal structure of the intestine ecosystem of the main symbiotes and representatives of the transient flora. To analyse the structure of symbiotic relationships, the constancy indices that form the microflora of the individuals of the groups studied were investigated. The analysis of the data obtained suggested that the dominant species in both groups were optional-anaerobic bifido and lactobacteria and oblique-anaerobic bacteroids. It should be noted, however, that in the residents of the dysfunctional Kirovsky district, against the background of the reduced constancy of the normal flora, opportunistic micro-organisms have entered. The floral significance index was also declining in the obligate flora of this group and increased for opportunistic species. Thus, the study of the environmental characteristics of the intestinal biotope using different ecological parameters for persons living in different technogenic load regions of St. Petersburg has shown that in the Kirov district with an unfavourable environmental situation there are compensated qualitative and quantitative changes in the intestinal microbiocenosis, resulting in a change in the hierarchy in the overall structure of micro-organisms.


Carbon ◽  
2021 ◽  
Author(s):  
Seungyoung Park ◽  
Seul Gi Ji ◽  
Yeoheung Yoon ◽  
Seong K. Kim ◽  
Wooseok Song ◽  
...  

Fluids ◽  
2018 ◽  
Vol 3 (3) ◽  
pp. 63 ◽  
Author(s):  
Thomas Meunier ◽  
Claire Ménesguen ◽  
Xavier Carton ◽  
Sylvie Le Gentil ◽  
Richard Schopp

The stability properties of a vortex lens are studied in the quasi geostrophic (QG) framework using the generalized stability theory. Optimal perturbations are obtained using a tangent linear QG model and its adjoint. Their fine-scale spatial structures are studied in details. Growth rates of optimal perturbations are shown to be extremely sensitive to the time interval of optimization: The most unstable perturbations are found for time intervals of about 3 days, while the growth rates continuously decrease towards the most unstable normal mode, which is reached after about 170 days. The horizontal structure of the optimal perturbations consists of an intense counter-shear spiralling. It is also extremely sensitive to time interval: for short time intervals, the optimal perturbations are made of a broad spectrum of high azimuthal wave numbers. As the time interval increases, only low azimuthal wave numbers are found. The vertical structures of optimal perturbations exhibit strong layering associated with high vertical wave numbers whatever the time interval. However, the latter parameter plays an important role in the width of the vertical spectrum of the perturbation: short time interval perturbations have a narrow vertical spectrum while long time interval perturbations show a broad range of vertical scales. Optimal perturbations were set as initial perturbations of the vortex lens in a fully non linear QG model. It appears that for short time intervals, the perturbations decay after an initial transient growth, while for longer time intervals, the optimal perturbation keeps on growing, quickly leading to a non-linear regime or exciting lower azimuthal modes, consistent with normal mode instability. Very long time intervals simply behave like the most unstable normal mode. The possible impact of optimal perturbations on layering is also discussed.


Aerospace ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 38
Author(s):  
Malik Doole ◽  
Joost Ellerbroek ◽  
Victor L. Knoop ◽  
Jacco M. Hoekstra

Large-scale adoption of drone-based delivery in urban areas promise societal benefits with respect to emissions and on-ground traffic congestion, as well as potential cost savings for drone-based logistic companies. However, for this to materialise, the ability of accommodating high volumes of drone traffic in an urban airspace is one of the biggest challenges. For unconstrained airspace, it has been shown that traffic alignment and segmentation can be used to mitigate conflict probability. The current study investigates the application of these principles to a highly constrained airspace. We propose two urban airspace concepts, applying road-based analogies of two-way and one-way streets by imposing horizontal structure. Both of the airspace concepts employ heading-altitude rules to vertically segment cruising traffic according to their travel direction. These airspace configurations also feature transition altitudes to accommodate turning flights that need to decrease the flight speed in order to make safe turns at intersections. While using fast-time simulation experiments, the performance of these airspace concepts is compared and evaluated for multiple traffic demand densities in terms of safety, stability, and efficiency. The results reveal that an effective way to structure drone traffic in a constrained urban area is to have vertically segmented altitude layers with respect to travel direction as well as horizontal constraints imposed to the flow of traffic. The study also makes recommendations for areas of future research, which are aimed at supporting dynamic traffic demand patterns.


2018 ◽  
Vol 64 (No. 7) ◽  
pp. 296-302 ◽  
Author(s):  
Dini Morteza ◽  
Nikooy Mehrdad ◽  
Naskovets Michael Trofimovich ◽  
Ghomi Alireza

In this research, the results of an experimental survey on the measurement of vertical stresses are presented. Four treatments were used in this study such as combination of geotextile vertical and horizontal structure with dimensions of 5 × 5 and 10 × 10 cm, horizontal geotextile and the treatment without geotextile. Five sensors were installed in different hole locations and the lead of the truck traffic was transmitted by cables to data logging and recording devices to measure the pressure from vehicle traffic on the simulated pavement layer. Mean comparison of the treatments showed that the geotextile with vertical and horizontal structure and dimensions of 5 × 5 cm exerted the lowest pressure on the lower layers compared with the other treatments and there was a significant difference between the value of this treatment and the other treatments and that this treatment could significantly reduce the pressure of truck traffic on the forest road.


2008 ◽  
Vol 38 (10) ◽  
pp. 2294-2307 ◽  
Author(s):  
Hristina G. Hristova ◽  
Joseph Pedlosky ◽  
Michael A. Spall

Abstract A linear stability analysis of a meridional boundary current on the beta plane is presented. The boundary current is idealized as a constant-speed meridional jet adjacent to a semi-infinite motionless far field. The far-field region can be situated either on the eastern or the western side of the jet, representing a western or an eastern boundary current, respectively. It is found that when unstable, the meridional boundary current generates temporally growing propagating waves that transport energy away from the locally unstable region toward the neutral far field. This is the so-called radiating instability and is found in both barotropic and two-layer baroclinic configurations. A second but important conclusion concerns the differences in the stability properties of eastern and western boundary currents. An eastern boundary current supports a greater number of radiating modes over a wider range of meridional wavenumbers. It generates waves with amplitude envelopes that decay slowly with distance from the current. The radiating waves tend to have an asymmetrical horizontal structure—they are much longer in the zonal direction than in the meridional, a consequence of which is that unstable eastern boundary currents, unlike western boundary currents, have the potential to act as a source of zonal jets for the interior of the ocean.


2015 ◽  
Vol 28 (23) ◽  
pp. 9332-9349 ◽  
Author(s):  
Liang Wu ◽  
Zhiping Wen ◽  
Renguang Wu

Abstract Part I of this study examined the modulation of the monsoon trough (MT) on tropical depression (TD)-type–mixed Rossby–gravity (MRG) and equatorial Rossby (ER) waves over the western North Pacific based on observations. This part investigates the interaction of these waves with the MT through a diagnostics of energy conversion that separates the effect of the MT on TD–MRG and ER waves. It is found that the barotropic conversion associated with the MT is the most important mechanism for the growth of eddy energy in both TD–MRG and ER waves. The large rotational flows help to maintain the rapid growth and tilted horizontal structure of the lower-tropospheric waves through a positive feedback between the wave growth and horizontal structure. The baroclinic conversion process associated with the MT contributes a smaller part for TD–MRG waves, but is of importance comparable to barotropic conversion for ER waves as it can produce the tilted vertical structure. The growth rates of the waves are much larger during strong MT years than during weak MT years. Numerical experiments are conducted for an idealized MRG or ER wave using a linear shallow-water model. The results confirm that the monsoon background flow can lead to an MRG-to-TD transition and the ER wave amplifies along the axis of the MT and is more active in the strong MT state. Those results are consistent with the findings in Part I. This indicates that the mean flow of the MT provides a favorable background condition for the development of the waves and acts as a key energy source.


2010 ◽  
Vol 11 (3) ◽  
pp. 210-214 ◽  
Author(s):  
Nicholas J. Souter ◽  
Shaun Cunningham ◽  
Stuart Little ◽  
Todd Wallace ◽  
Bernard McCarthy ◽  
...  

2021 ◽  
Vol 970 (4) ◽  
pp. 35-44
Author(s):  
G.I. Lysanova ◽  
Ju.M. Semenov ◽  
A.A. Sorokovoi ◽  
I.V. Balyazin

The сlassification of geosystem used in mapping is based on a system-hierarchic approach to detecting the co-involvement of landscape taxons. At the same time, we took into account the positioning of individual territories in the system of physical- geographical regionalization. The complexity of the landscape structure of the studied territory is due to its location at the junction of high- and lowland regions belonging to four physical-geographical areas. In the area under study, we identified and described more than 200 groups of fairies, which were then typed into classes of facies, geomes, and groups of geomes. Geoinformation mapping is performed using vector topographic basis and Earth remote sensing data. The decryption of synthesized space images was carried out manually and was based on field landscape surveys data. Digitization and indexing of landscape contours, creation, design and layout of the map were carried out in GIS MapInfo Professional. The cartographical analysis revealed regional differences in the complexity of landscape horizontal structures of high- and lowland regions, as well as the composition and structure of typological spectra of regional geosystems. Lowland geosystems mostly have a fairly uniform horizontal structure and large areas of landscape patterns. At the same time, mountain areas are characterized by considerable complexity and contrast of landscape structure.


Sign in / Sign up

Export Citation Format

Share Document