scholarly journals Modeling of spatial variations of growth within apical domes by means of the growth tensor. L Growth specified on dome axis

2014 ◽  
Vol 53 (1) ◽  
pp. 17-28 ◽  
Author(s):  
Zygmunt Hejnowicz ◽  
Jerzy Nakielski ◽  
Krystyna Hejnowicz
Keyword(s):  
Growth Rates ◽  
Distal Region ◽  
Spatial Variations ◽  
Coordinate Systems ◽  
Prolate Spheroidal ◽  
Dome A ◽  
Lower Growth ◽  
Apical Dome ◽  
Curvilinear Coordinate ◽  
Natural Coordinate

By using the growth tensor and a natural curvilinear coordinate system for description of the distribution of growth in plant organs, three geometric types of shoot apical domes (parabolic, elliptical and hyperbolic) were modeled. It was assumed that apical dome geometry remains unchanged during growth and that the natural coordinate systems are paraboloidal and prolate spheroidal. Two variants of the displacement velocity fields V were considered. One variant is specified by a constant relative elemental rate of growth along the axis of the dome. The second is specified by a rate increasing proportionally with distance from the geometric focus of the coordinate systems (and the apical dome). The growth tensor was used to calculate spatial variations of growth rates for each variant of each dome type. There is in both variants a clear tendency toward lower growth rates in the distal region of the dome. A basic condition for the existence of a tunica is met.

scholarly journals Spatial variations of growth within domes having different patterns of principal growth directions

2014 ◽  
Vol 56 (4) ◽  
pp. 611-623 ◽  
Author(s):  
Jerzy Nakielski
Keyword(s):  
Growth Rate ◽  
Coordinate System ◽  
Growth Rates ◽  
Relative Rate ◽  
Spatial Variations ◽  
Coordinate Systems ◽  
Dome A ◽  
Rate Of Growth ◽  
Natural Coordinate System ◽  
Natural Coordinate

Growth rate variations for two paraboloidal domes: A and B, identical when seen from the outside but differing in the internal pattern of principal growth directions, were modeled by means of the growth tensor and a natural coordinate system. In dome A periclinal trajectories in the axial plane were given by confocal parabolas (as in a tunical dome), in dome B by parabolas converging to the vertex (as in a dome without a tunica). Accordingly, two natural coordinate systems, namely paraboloidal for A and convergent parabolic for B, were used. In both cases, the rate of growth in area on the surfaces of domes was assumed to be isotropic and identical in corresponding points. It appears that distributions of growth rates within domes A and B are similar in their peripheral and central parts and different only in their distal regions. In the latter, growth rates are relatively large; the maximum relative rate of growth in volume is around the geometric focus in dome A, and on the surface around the vertex in dome B.

scholarly journals Modeling of spatial variations of growth within apical domes by means of the growth tensor. II. Growth specified on dome surface

2014 ◽  
Vol 53 (3) ◽  
pp. 301-316 ◽  
Author(s):  
Zygmunt Hejnowicz ◽  
Jerzy Nakielski ◽  
Krystyna Hejnowicz
Keyword(s):  
Growth Rate ◽  
Coordinate System ◽  
Growth Rates ◽  
Relative Rate ◽  
Spatial Variations ◽  
Curvilinear Coordinate System ◽  
Volumetric Growth ◽  
Shoot Apices ◽  
Curvilinear Coordinate ◽  
Area Growth

Variations of the elemental relative rate of growth are modeled for parabolic, elliptic and hyperbolic domes of shoot apices by using the growth tensor in a suitable curvilinear coordinate system when the mode of area growth on the dome surface is known. Variations of growth rates within the domes are obtained in forms of computer-made maps for the following variants of growth on the dome surface: (1) constant meridional growth rate, (2) isotropic area growth, (3) anisotropy of area growth which becomes more intensive with increasing distance from the vertex. In variants 1 and 2 a maximum of volumetric growth rate appears in the center of the dome. Such a distribution of growth seems to be unrealistic. However, the corresponding growth tensors are interesting because they can be used in combination with other growth tensors to get the expected minimum volumetric growth rate in the dome center.

Effects of lice infestation on the growth of beef heifers in Victoria

1984 ◽  
Vol 24 (125) ◽  
pp. 140 ◽  
Author(s):  
PJ Bailey ◽  
WAD Carroll ◽  
B Knee
Keyword(s):  
Growth Rates ◽  
Beef Heifers ◽  
Lower Growth ◽  
High Rainfall ◽  
Main Species ◽  
Western Victoria ◽  
Linognathus Vituli

Ten experiments were carried out to examine some of the effects of lice infestation on heifers grazing on six commercial properties in the high rainfall areas of Victoria. In all experiments, famphur, a pour-on lousicide, effectively controlled lice populations (main species Linognathus vituli). Lice infestation was associated with lower growth rates in only two experiments. Significant correlations between lice infestation and liveweight gain of untreated heifers were found in three of ten experiments, but infestation accounted for only 23-30% of the variation in liveweight gain. The results support other studies conducted in Western Victoria, and the need for routine whole herd treatment against lice is questioned.

Do abiotic mechanisms determine interannual variability in length-at-age of juvenile Arcto-Norwegian cod?

2002 ◽  
Vol 59 (1) ◽  
pp. 57-65 ◽  
Author(s):  
Geir Ottersen ◽  
Kristin Helle ◽  
Bjarte Bogstad
Keyword(s):  
Growth Rates ◽  
Gadus Morhua ◽  
Barents Sea ◽  
Water Masses ◽  
Inverse Relation ◽  
Lower Growth ◽  
Density Dependent ◽  
The Barents Sea ◽  
The Mean ◽  
Dependent Growth

For the large Arcto-Norwegian stock of cod (Gadus morhua L.) in the Barents Sea, year-to-year variability in growth is well documented. Here three hypotheses for the observed inverse relation between abundance and the mean length-at-age of juveniles (ages 1–4) are suggested and evaluated. Based on comprehensive data, we conclude that year-to-year differences in length-at-age are mainly determined by density-independent mechanisms during the pelagic first half year of the fishes' life. Enhanced inflow from the southwest leads to an abundant cohort at the 0-group stage being distributed farther east into colder water masses, causing lower postsettlement growth rates. We can not reject density-dependent growth effects related to variability in food rations, but our data do not suggest this to be the main mechanism. Another hypothesis suggests that lower growth rates during periods of high abundance are a result of density-dependent mechanisms causing the geographic range of juveniles to extend eastwards into colder water masses. This is rejected mainly because year-to-year differences in mean length are established by age 2, which is too early for movements over large distances.

scholarly journals Implementation of an Approximate Conformal UPML in 2-D DGTD

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Linqian Li ◽  
Bing Wei ◽  
Qian Yang ◽  
Debiao Ge
Keyword(s):  
Good Accuracy ◽  
Computation Time ◽  
Elliptic Cylinder ◽  
Auxiliary Equation ◽  
Coordinate Systems ◽  
Absorbing Boundary ◽  
Computational Region ◽  
Curvilinear Coordinate ◽  
Orthogonal Curvilinear Coordinate System ◽  
Absorbing Layer

Using the numerical discrete technique with unstructured grids, conformal perfectly matched layer (PML) absorbing boundary in the discontinuous Galerkin time-domain (DGTD) can be set flexibly so as to save lots of computing resources. Based on the DGTD equations in an orthogonal curvilinear coordinate system, the processes of parameter transformation for 2-D UPML between the coordinate systems of elliptical and Cartesian are given; and the expressions of transition matrix are derived. The calculation scheme of conductivity distribution in elliptic cylinder absorbing layer is given, and the calculation coefficient of DGTD in elliptic UPML is calculated. Furthermore, the 2-D iterative formulas of DGTD and that of auxiliary equation in the elliptical cylinder UPML are derived; the conformal UPML calculation in DGTD is realized. Numerical results show that very good accuracy and computational efficiency are achieved by using the method in this paper. Compared to the rectangular computational region, both the memory and computation time of conformal UPML absorbing boundary are reduced by more than 20%.

The impact of endophyte on the health and productivity of sheep grazing ryegrass-based pastures

1999 ◽  
Vol 7 ◽  
pp. 11-17
Author(s):  
L.R. Fletcher ◽  
B.L. Sutherland ◽  
C.G. Fletcher
Keyword(s):  
Perennial Ryegrass ◽  
Growth Rates ◽  
Plasma Prolactin ◽  
Sheep Grazing ◽  
Wild Type ◽  
Lower Plasma ◽  
Lower Growth ◽  
Respiration Rates ◽  
Neotyphodium Lolii ◽  
The Impact

The health and production of sheep grazing perennial ryegrass with and without wild-type endophyte (Neotyphodium lolii) has been studied in several trials over a number of years. Lambs/ hoggets grazing predominantly perennial ryegrass swards with endophyte developed moderate to severe ryegrass staggers in summer and autumn, while those grazing endophyte-free ryegrass did not. Lambs/hoggets grazing ryegrass with endophyte also had more dags, lower growth rates, lower plasma prolactin levels, higher body temperatures and respiration rates under warm humid conditions. Most of these adverse responses were more severe in summer and autumn when endophyte toxin concentrations were highest. Many of these symptoms are similar to those described for the "autumn ill thrift" syndrome in New Zealand. Keywords: dags, endophyte, flystrike, growth rates, hyperthermia, Neotyphodium, perennial ryegrass, prolactin, ryegrass staggers, sheep

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