scholarly journals PRODUCTIVITY OF MOTHER PLANTATIONS OF PUMISELECT CLONE CLOSURE DURING GROWING BY VERTICAL AND HORIZONTAL LAYERS

2020 ◽  
Vol 2 ◽  
pp. 99-104
Author(s):  
V. V. Zamorsky
Keyword(s):  
Horizontal Layers

scholarly journals A Field Study of Brine Drainage and Oil Entrainment in First-Year Sea Ice

1979 ◽  
Vol 22 (88) ◽  
pp. 473-502 ◽  
Author(s):  
Seelye Martin
Keyword(s):  
Sea Ice ◽  
Growth And Development ◽  
Salt Transport ◽  
First Year ◽  
Field Observations ◽  
Melt Pond ◽  
Ice Surface ◽  
Melt Ponds ◽  
Brine Channel ◽  
Horizontal Layers

AbstractFrom field observations this paper describes the growth and development of first-year sea ice and its interaction with petroleum. In particular, when sea ice initially forms, there is an upward salt transport so that the ice surface has a highly saline layer, regardless of whether the initial ice is frazil, columnar, or slush ice. When the ice warms in the spring, because of the eutectic condition, the surface salt liquifies and drains through the ice, leading to the formation of top-to-bottom brine channels and void spaces in the upper part of the ice. If oil is released beneath winter ice, then the oil becomes entrained in thin lenses within the ice. In the spring, this oil flows up to the surface through the newly-opened brine channels and distributes itself within the brine-channel feeder systems, on the ice surface, and in horizontal layers in the upper part of the ice. The paper shows that these layers probably form from the interaction of the brine drainage with the percolation of melt water from surface snow down into the ice and the rise of the oil from below. Finally in the summer, the oil on the surface leads to melt-pond formation. The solar energy absorbed by the oil on the surface of these melt ponds eventually causes the melt pond to melt through the ice, and the oil is again released into the ocean.

Taxonomic affinities and paleogeography of Stromatomorpha californica Smith, a distinctive Upper Triassic reef-adapted demosponge

2009 ◽  
Vol 83 (5) ◽  
pp. 783-793 ◽  
Author(s):  
B. Senowbari-Daryan ◽  
G. D. Stanley
Keyword(s):  
North America ◽  
Shallow Water ◽  
Type Species ◽  
Upper Triassic ◽  
Northern Calcareous Alps ◽  
Late Triassic ◽  
Separate Species ◽  
Northern Calcareous ◽  
Siliceous Spicules ◽  
Horizontal Layers

Stromatomorpha californica Smith is a massive, calcified, tropical to subtropical organism of the Late Triassic that produced small biostromes and contributed in building some reefs. It comes from the displaced terranes of Cordilleran North America (Eastern Klamath terrane, Alexander terrane, and Wrangellia). This shallow-water organism formed small laminar masses and sometimes patch reefs. It was first referred to the order Spongiomorphidae but was considered to be a coral. Other affinities that have been proposed include hydrozoan, stomatoporoid, sclerosponge, and chambered sponge. Part of the problem was diagenesis that resulted in dissolution of the siliceous spicules and/or replaced them with calcite. Well-preserved dendroclone spicules found during study of newly discovered specimens necessitate an assignment of Stromatomorpha californica to the demosponge order Orchocladina Rauff. Restudy of examples from the Northern Calcareous Alps extends the distribution of this species to the Tethys, where it was an important secondary framework builder in Upper Triassic (Norian-Rhaetian) reef complexes. Revisions of Stromatomorpha californica produce much wider pantropical distribution, mirroring paleogeographic patterns revealed for other tropical Triassic taxa. Review of Liassic material from the Jurassic of Morocco, previously assigned to Stromatomorpha californica Smith var. columnaris Le Maitre, cannot be sustained. Species previously included in Stromatomorpha are: S. stylifera Frech (type species, Rhaetian), S. actinostromoides Boiko (Norian), S. californica Smith (Norian), S. concescui Balters (Ladinian-Carnian), S. pamirica Boiko (Norian), S. rhaetica Kühn (Rhaetian), S. stromatoporoides Frech, and S. tenuiramosa Boiko (Norian). Stromatomorpha rhaetica Kühn described from the Rhaetian of Vorarlberg, Austria shows no major difference from S. californica. An example described as S. oncescui Balters from the Ladinian-Carnian of the Rarau Mountains, Romania, is very similar to S. californica in exhibiting similar spicule types. However, because of the greater distance between individual pillars, horizontal layers, and the older age, S. oncescui is retained as a separate species. The net-like and regular skeleton of Spongiomorpha sanpozanensis Yabe and Sugiyama, from the Upper Triassic of Sambosan (Tosa, Japan), suggests a closer alliance with Stromatomorpha, and this taxon possibly could be the same as S. californica.

Templates for Neural Dynamics in the Striatum: Striosomes and Matrisomes

2017 ◽  
pp. 133-142
Author(s):  
Ann M. Graybiel
Keyword(s):  
Neural Dynamics ◽  
Major Influence ◽  
Human Language ◽  
Motor Functions ◽  
Subcortical Region ◽  
System P ◽  
Human Disorders ◽  
Lower Structure ◽  
Horizontal Layers

The striatum appears to be a relatively simple forebrain region compared to the overlying neocortex, with its horizontal layers and vertical columns. In fact, the striatum in mammals has a sophisticated architecture of its own. This large subcortical region is now suspected of having a major influence on how the neocortex carries out its own functions—even functions related to human language. Furthermore, abnormalities in the striatum are increasingly being discovered in human disorders affecting both cognitive and motor functions. It is, as a consequence, increasingly difficult to see the neocortex as a higher structure and the striatum as a lower structure in terms of their influence on behavior. The chapter is not a full review of this topic, but it points out some findings from the author’s laboratory that hint at such functions for the striosomal system.

scholarly journals Groundwater flow below construction pits and erosion of temporary horizontal layers of silicate grouting

2020 ◽  
Vol 28 (8) ◽  
pp. 2821-2832
Author(s):  
Joris M. Dekker ◽  
Thomas Sweijen ◽  
Alraune Zech
Keyword(s):  
Hydraulic Conductivity ◽  
Groundwater Flow ◽  
Analytical Solutions ◽  
Mass Flux ◽  
Approximate Solutions ◽  
Sensitivity Study ◽  
Advective Transport ◽  
Dilution Ratio ◽  
The Impact ◽  
Horizontal Layers

AbstractInjection of silicate grouting materials is widely used to create temporary horizontal layers for reducing inflow of groundwater at construction sites, in regions with shallow water tables. The erosion of a grouting layer was investigated by means of analytical solutions for groundwater flow and transport within a pit after construction finished. Erosion is assumed to occur by dissolution of the temporary injection layer and subsequent advective transport. Thereby, the hydraulic conductivity changes with time. This paper presents novel analytical solutions and approximate solutions for the major fluxes in the construction pit as a function of the domain settings, aquifer gradient and hydraulic conductivity. In addition, the mass flux and the dilution ratio of erosion-related components leaving the construction pit and entering the aquifer are quantified. Derived solutions are verified against numerical simulations. A sensitivity study shows the impact of domain settings on fluxes and dilution ratio. The results confirm that mass flux of grout components increases with ongoing erosion. Thus, its effect on groundwater quality increases with time after construction ceased.

Experiments on the inhibition of thermal convection by a magnetic field

1957 ◽  
Vol 240 (1220) ◽  
pp. 108-113 ◽  
Keyword(s):  
Magnetic Field ◽  
Electrical Conductivity ◽  
Rayleigh Number ◽  
Magnetic Fields ◽  
Thermal Convection ◽  
Kinematic Viscosity ◽  
Critical Rayleigh Number ◽  
Theoretical Relation ◽  
Horizontal Layers

Experiments on the magnetic inhibition of thermal convection in horizontal layers of mercury heated from below are described. A large 36½ in. cyclotron magnet reconditioned for hydromagnetic studies was used in these experiments. By using layers of mercury of depth 3 to 6 cm and magnetic fields of strength 500 to 8000 gauss, it has been possible to determine the dependence of the critical Rayleigh number for the onset of instability on the parameter Q 1 ( = σH 2 d 2 / π 2 ρν , where H denotes the strength of the field, σ the electrical conductivity, ν the coefficient of kinematic viscosity, ρ the density and d the depth of the layer) for Q 1 varying between 40 and 1·6 × 10 6 . The experiments fully confirm the theoretical relation derived by Chandrasekhar.

scholarly journals Radio Echo Sounding of Horizontal Layers in Ice

1973 ◽  
Vol 12 (66) ◽  
pp. 383-397 ◽  
Author(s):  
C. H. Harrison
Keyword(s):  
Dielectric Constant ◽  
Reflection Coefficient ◽  
Ice Crystals ◽  
Fractional Change ◽  
Dielectric Absorption ◽  
Radio Echo Sounding ◽  
The Antarctic ◽  
Horizontal Layers ◽  
Effective Reflection Coefficient ◽  
Echo Sounding

Radio echo-sounding surveys of Antarctica and Greenland have revealed extensive layering within the ice. Formulae for the effective reflection coefficient, when viewed by a pulsed radar, are derived for isolated or multiple randomly spaced layers. In the latter case the variation in dielectric constant with depth is described by a vertical autocorrelation function and a standard deviation. Some measurements of the reflection coefficient of layers, and the dielectric absorption of ice are given. The significance of the fading of layer echoes and the possible causes of variations in the dielectric constant are considered and some further investigations are suggested. It is concluded that the echo strengths found in the Antarctic may be explained by multiple layering, and that the necessary fractional change in the dielectric constant may be as small as 10−4. It is suggested that this change in dielectric constant may be due to differences in orientation of anisotropic ice crystals.

Pseudo-Ice-Wedge Casts of Connecticut, Northeastern United States

1983 ◽  
Vol 20 (1) ◽  
pp. 74-89 ◽  
Author(s):  
Robert F. Black
Keyword(s):  
United States ◽  
Water Table ◽  
Physical Environment ◽  
Northeastern United States ◽  
Complex Fracture ◽  
Ice Wedge ◽  
Sand And Gravel ◽  
Coated Sand ◽  
Horizontal Layers

AbstractSince 1965, ice-wedge casts have been reported in deposits of sand and gravel in Connecticut. These are wedge forms up to 1.1 m wide and many meters high. Most are single forms, not in polygonal array. They are found in adjoining states as well. Their distribution, dimensions, structure, and fabric and an assessment of the former physical environment preclude their origin as permafrost features. They appear to be tension fractures produced by the loading of coarse clastics on fine clastics near and below the water table where sediments creep toward a stream or depression. Locally movement started with kettle formation during deglaciation. However, some wedges cut horizontal layers of iron-coated sand and gravel and must be younger than those distinctly postglacial phenomena. Moreover, modern B horizons of the overlying soil have moved down into some wedges more than 2 m, indicating that fracturing is still active today. Complex fracture fillings in bedrock also have been attributed to a permafrost origin, but this too seems unlikely.

scholarly journals Does a ‘turbophoretic’ effect account for layer concentrations of insects migrating in the stable night-time atmosphere?

2008 ◽  
Vol 6 (30) ◽  
pp. 87-95 ◽  
Author(s):  
A.M Reynolds ◽  
D.R Reynolds ◽  
J.R Riley
Keyword(s):  
Vertical Profile ◽  
Temperature Inversion ◽  
Nocturnal Boundary Layer ◽  
Local Minima ◽  
Layer Formation ◽  
Night Time ◽  
Local Maxima ◽  
Neutrally Buoyant ◽  
Obvious Feature ◽  
Horizontal Layers

Large migrating insects, such as noctuid moths and acridoid grasshoppers, flying within the stable nocturnal boundary layer commonly become concentrated into horizontal layers. These layers frequently occur near the top of the surface temperature inversion where warm fast-moving airflows provide good conditions for downwind migration. On some occasions, a layer may coincide with a higher altitude temperature maximum such as a subsidence inversion, while on others, it may seem unrelated to any obvious feature in the vertical profile of meteorological variables. Insects within the layers are frequently orientated, either downwind or at an angle to the wind, but the mechanisms involved in both layer formation and common orientation have remained elusive. Here, we show through the results of numerical simulations that if insects are treated as neutrally buoyant particles, they tend to be advected by vertical gusts (through the ‘turbophoretic’ mechanism) into layers in the atmosphere where the turbulent kinetic energy has local minima. These locations typically coincide with local maxima in the wind speed and/or air temperature, and they may also provide cues for orientation. However, the degree of layering predicted by this model is very much weaker than that observed in the field. We have therefore hypothesized that insects behave in a way that amplifies the turbophoretic effect by initiating climbs or descents in response to vertical gusts. New simulations incorporating this behaviour demonstrated the formation of layers that closely mimic field observations, both in the degree of concentration in layers and the rate at which they form.

Three-dimensional diffraction theory of microscope image formation

1952 ◽  
Vol 212 (1109) ◽  
pp. 264-274 ◽  
Keyword(s):  
Three Dimensional ◽  
Image Formation ◽  
Diffraction Theory ◽  
X Rays ◽  
Vertical Separation ◽  
Standard Methods ◽  
Microscope Image ◽  
Diffraction Of Light ◽  
Dimensional Object ◽  
Horizontal Layers

The Abbe theory of image formation for a plane object is extended to apply to the case of a three-dimensional object. The diffraction of light by such an object is treated by the standard methods applied to the diffraction of X-rays by crystals. The formation of an image of a three-dimensional periodic object is discussed, and it is shown that certain Fourier components of the structure of the object are reproduced in the image while others are left out. An expression is obtained for the minimum vertical separation between horizontal layers that can just be resolved by racking the microscope up and down; this depends on the scale of the detail in the layers.

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