Some systematic aspects of Mitchell grasses (Astrebla F. Muell.)

1969 ◽  
Vol 17 (2) ◽  
pp. 359 ◽  
Author(s):  
FX Jozwik
Keyword(s):  
Leaf Anatomy ◽  
Interspecific Hybrids ◽  
Large Scale ◽  
Species Distributions ◽  
Circumstantial Evidence ◽  
Clay Soils ◽  
Field Observations ◽  
Cross Pollination ◽  
F1 Generation

The systematics of the genus Astrebla were studied with use of morphological, distributional, anatomical, and breeding characteristics. Results show that the genus is a group of closely related but well-defined species. The occurrence of F1 interspecific hybrids is strongly suggested from field observations and glasshouse plantings but because of sterility in the F1 generation hybridization between species apparently plays little part in continuing evolution. Species distributions are closely correlated with the occurrence of cracking clay soils and show large discontinuities. Although Astrebla pectinata, A. elymoides, and A. Squarrosa are common on the Barkly Tableland A. lappacea is generally absent from that area.. Internal and epidermal leaf anatomy indicates that Astrebla is related to the chloridoid line of grasses. Prevention of cross-pollination showed that all species are highly self-compatible. Circumstantial evidence suggests that large-scale apomixis does not occur.

scholarly journals Engineering and environmental benefits of using construction wastes in ground improvement works

2020 ◽  
Vol 310 ◽  
pp. 00024
Author(s):  
Cornelia-Florentina Dobrescu ◽  
Elena-Andreea Calarasu
Keyword(s):  
Large Scale ◽  
Ground Improvement ◽  
Environmental Benefits ◽  
Clay Soils ◽  
Curing Time ◽  
Swelling Potential ◽  
Geotechnical Parameters ◽  
Construction Waste ◽  
Emerging Trends ◽  
Water Based

One of the key emerging trends to protect the environment is to reuse wastes generated from construction and demolition sites for various engineering purposes. Many studies are being developed for setting up and optimize the potential of recycled construction wastes. The aim of the paper is to estimate the degree of improvement for resistance parameters of soil mixed with 5% and 10% of concrete and brick and water-based polymeric suspension used as stabilizer agent, as well as drywall waste mixed with 5% eco-binder with puzzolanic character. Multiple options of mixtures, predominantly composed by clay soils with swelling potential, have been investigated in laboratory conditions in terms of compression strength at 7, 14 and 28 days curing time and deformability. In order to emphasize distinct benefits of tested mixtures, a comparative analysis of the parametric values has been achieved. The experimental results revealed the suitability of using construction wastes to be assimilated with natural or conventional materials, which leads to significant improvements rates of geotechnical parameters. A large-scale implementation of this type of practice can substantially contribute to the achievement of sustainable development targets by reusing construction waste according to the specific objectives of engineering works in terms of structure safety.

Decomposing the heterogeneity of species distributions into multiple scales: a hierarchical framework for large-scale count surveys

Ecography ◽  
2012 ◽  
Vol 35 (9) ◽  
pp. 839-854 ◽  
Author(s):  
Edwige Bellier ◽  
Pascal Monestiez ◽  
Grégoire Certain ◽  
Joël Chadoeuf ◽  
Vincent Bretagnolle
Keyword(s):  
Large Scale ◽  
Multiple Scales ◽  
Species Distributions ◽  
Hierarchical Framework ◽  
Count Surveys

scholarly journals SHORELINE ROTATION CAUSED BY LARGE-SCALE EXCAVATION OF REEF FLAT ON SANUR BEACH IN BALI

2011 ◽  
Vol 1 (32) ◽  
pp. 93
Author(s):  
Masatoshi Endo ◽  
Akio Kobayashi ◽  
Takaaki Uda ◽  
Yasuhito Noshi ◽  
Susumu Onaka
Keyword(s):  
Numerical Simulations ◽  
Large Scale ◽  
Reef Flat ◽  
Beach Nourishment ◽  
Beach Erosion ◽  
Field Observations ◽  
Wave Direction ◽  
Bathymetric Survey ◽  
Shoreline Changes ◽  
S Model

In the southern part of Sanur Beach in Bali, beach erosion has occurred between groins after extensive beach nourishment, resulting in shoreline rotation between the groins. The cause of shoreline changes was investigated by field observations, including a bathymetric survey and the sampling of seabed materials, and numerical simulations of beach changes were carried out using Noshi et al.’s model. It was concluded that the shoreline rotation was triggered by the dredging of the reef flat, which caused a change in the wave direction on the reef flat due to the diffraction of waves.

scholarly journals Technical note: Interpretation of field observations of point-source methane plume using observation-driven large-eddy simulations

2021 ◽  
Author(s):  
Anja Ražnjević ◽  
Chiel van Heerwaarden ◽  
Bart van Stratum ◽  
Arjan Hensen ◽  
Ilona Velzeboer ◽  
...  
Keyword(s):  
Point Source ◽  
Large Scale ◽  
Added Value ◽  
Relative Dispersion ◽  
Scale Model ◽  
Length Scale ◽  
Oil Well ◽  
Plume Dispersion ◽  
Field Observations ◽  
Large Eddy

Abstract. This study demonstrates the ability of large-eddy simulation (LES) forced by a large-scale model to reproduce plume dispersion in an actual field campaign. Our aim is to bring together field observations taken under non-ideal conditions and LES to show that this combination can help to derive point source strengths from sparse observations. We prepared a one-day case study based on data collected near an oil well during the ROMEO campaign (ROmanian Methane Emissions from Oil and gas) that took place in October 2019. We set up our LES using boundary conditions derived from the meteorological reanalysis ERA5 and released a point source in line with the configuration in the field. The weather conditions produced by the LES show close agreement with field observations, although the observed wind field showed complex features due to the absence of synoptic forcing. In order to align the plume direction with field observations, we created a second simulation experiment with manipulated wind fields. The estimated source strengths using the LES plume agrees well with the emitted artificial tracer gas plume, indicating the suitability of LES to infer source strengths from observations under complex conditions. To further harvest the added value of LES, higher order statistical moments of the simulated plume were analysed. Here, we found good agreement with plumes from previous LES and laboratory experiments in channel flows. We derived a length scale of plume mixing from the boundary layer height, the mean wind speed and convective velocity scale. It was demonstrated that this length scale represents the distance from the source at which the predominant plume behaviour transfers from meandering dispersion to relative dispersion.

scholarly journals Data Integration for Large-Scale Models of Species Distributions

2020 ◽  
Vol 35 (1) ◽  
pp. 56-67 ◽  
Author(s):  
Nick J.B. Isaac ◽  
Marta A. Jarzyna ◽  
Petr Keil ◽  
Lea I. Dambly ◽  
Philipp H. Boersch-Supan ◽  
...  
Keyword(s):  
Data Integration ◽  
Large Scale ◽  
Species Distributions ◽  
Scale Models

Analysis of a large-scale water supply system of the Byzantine period using modern fluid mechanics

2007 ◽  
Vol 7 (1) ◽  
pp. 183-190
Author(s):  
B. Haut ◽  
D. Viviers
Keyword(s):  
Water Supply ◽  
Large Scale ◽  
Water Flow Rate ◽  
Quantitative Description ◽  
Supply System ◽  
Water Supply System ◽  
Point Of View ◽  
Field Observations ◽  
Byzantine Period ◽  
The City

In this paper, the flow of water in several elements of the water supply system of the city of Apamea is simulated. The studied elements were used at the end of the 6th century AD (Byzantine period). These simulations allow for the analysis of the water supply system from a modern point of view, in terms of water flow rate, energy loss, etc. This analysis provides a quantitative description of the water supply system of the city, supplementing the field observations.

Outcrossing in interspecific hybrids between Eucalyptus spathulata and E. platypus

2005 ◽  
Vol 53 (4) ◽  
pp. 347 ◽  
Author(s):  
M. A. B. Wallwork ◽  
M. Sedgley
Keyword(s):  
Interspecific Hybrids ◽  
Female Parent ◽  
Pollen Tubes ◽  
The Other ◽  
Parent Species ◽  
Cross Pollination ◽  
Seed Maturity ◽  
Self Pollination ◽  
Ovule Penetration ◽  
Zygotic Control

Outcrossing was investigated in interspecific hybrids between self-fertile Eucalyptus platypus Blakely and partially self-sterile E. spathulata Hook., which shows both pre- and post-zygotic timing. Four hybrid trees were used for the study, two with E. spathulata and two with E. platypus as female parent. Each hybrid had a similar number of locules to each other and to the E. platypus parent, and an intermediate number of ovules per flower compared with the parent species. Controlled hand-pollinations were carried out, in which both self- and cross-pollen from the other hybrid tree with the same female parent species was applied to flowers on each of the four trees, and observations were made 10days, 4weeks and 8weeks after pollination and at seed maturity. In all hybrids, mean seeds per capsule was consistently higher following cross-pollination than following self-pollination. All hybrids showed a reduction in pollen tube number between the top and base of the style when examined by fluorescence microscopy. One tree had significantly fewer cross- than self-pollen tubes at the base of the style, but a similar number of ovules was penetrated by pollen tubes following both treatments. In the other three, there was no difference between cross- and self-pollination in pollen tubes in the style. In three of the four trees there was no difference in ovule penetration following self- or cross-pollination, but in the other, more crossed than selfed ovules were penetrated. Light-microscopy observation of ovules indicated that ovule abortion following fertilisation accounted for the reduced numbers of seeds following self-pollination and to a lesser extent following cross-pollination. All four hybrid trees, irrespective of female parent, were partially self-sterile and resembled the partially self-sterile E. spathulata rather than the self-fertile E. platypus. While the timing of outcrossing control of E. spathulata was both pre- and post-zygotic, only one hybrid was similar, with the other three showing post-zygotic control.

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