The Distribution of the Nests of the Magpie Goose (Anseranas-Semipalmata Latham) at Kapalga, Nt - a 4-Year Study

1988 ◽  
Vol 15 (2) ◽  
pp. 211 ◽  
Author(s):  
D Tulloch ◽  
KM Cellier ◽  
AL Hertog
Keyword(s):  
Water Depth ◽  
Deep Water ◽  
Intermediate Water ◽  
Vegetation Types ◽  
Oryza Meridionalis ◽  
Maximum Water ◽  
One Year ◽  
A Site ◽  
The Relationship ◽  
Made In

A survey of the distribution and abundance of nests of the magpie goose (Anseranas semipalmata Latham) was carried out over 4 years (1980-83 inclusive) at a site covering about 1000 ha on the South Alligator River floodplain at Kapalga, N.T. There were large differences in the number of nests built from year to year. Maximum water depth on the plains and the length of time the plains were flooded varied considerably from year to year and since these factors have an effect on the type and distribution of the vegetation, a study of the relationship between the density of nests, water depth and the vegetation present was made in each year. Breeding was confined to three recognisable vegetation types: (1) a mixture of spike rushes, Eleocharis spp., and wild rice, Oryza meridionalis; (2) pure stands of Oryza meridionalis; (3) pure stands of Eleocharis sphacelata. The density of nests was higher in areas of Eleocharis spp./Oryza meridionalis mixture than in E. sphacelata or 0. rneridionalis and in 3 years out of 4, more nests were built in deep water rather than shallow, while in the fourth year nests were built at intermediate water depths. Significant numbers of nests were built in the areas of Oryza meridionalis in only one year when the density of nests was greater in deep water rather than shallow.

scholarly journals Effects of Water Depth on the Growth of the Submerged Macrophytes Vallisneria natans and Hydrilla verticillata: Implications for Water Level Management

Water ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 2590
Author(s):  
Qisheng Li ◽  
Yanqing Han ◽  
Kunquan Chen ◽  
Xiaolong Huang ◽  
Kuanyi Li ◽  
...  
Keyword(s):  
Water Level ◽  
Water Depth ◽  
Deep Water ◽  
Submerged Macrophytes ◽  
Hydrilla Verticillata ◽  
Water Level Fluctuations ◽  
Total Biomass ◽  
Intermediate Water ◽  
Factors Affecting ◽  
Vallisneria Natans

Water level is one of the most important factors affecting the growth of submerged macrophytes in aquatic ecosystems. The rosette plant Vallisneria natans and the erect plant Hydrilla verticillata are two common submerged macrophytes in lakes of the middle and lower reaches of the Yangtze River, China. How water level fluctuations affect their growth and competition is still unknown. In this study, three water depths (50 cm, 150 cm, and 250 cm) were established to explore the responses in growth and competitive patterns of the two plant species to water depth under mixed planting conditions. The results show that, compared with shallow water conditions (50 cm), the growth of both submerged macrophytes was severely suppressed in deep water depth (250 cm), while only V. natans was inhibited under intermediate water depth (150 cm). Moreover, the ratio of biomass of V. natans to H. verticillata gradually increased with increasing water depth, indicating that deep water enhanced the competitive advantage of V. natans over H.verticillata. Morphological adaptation of the two submerged macrophytes to water depth was different. With increasing water depth, H. verticillata increased its height, at the cost of reduced plant numbers to adapt to poor light conditions. A similar strategy was also observed in V. natans, when water depth increased from 50 cm to 150 cm. However, both the plant height and number were reduced at deep water depth (250 cm). Our study suggests that water level reduction in lake restoration efforts could increase the total biomass of submerged macrophytes, but the domination of key plants, such as V. natans, may decrease.

Odour Problems in Two Reservoirs

1983 ◽  
Vol 15 (6-7) ◽  
pp. 25-33 ◽  
Author(s):  
P Popovska
Keyword(s):  
Surface Water ◽  
Dissolved Oxygen ◽  
Water Temperature ◽  
Multiple Regression ◽  
Statistical Methods ◽  
Water Depth ◽  
Negative Correlation ◽  
One Year ◽  
The Relationship ◽  
Temperature Depth

The Klicava reservoir was regularly monitored for almost two years. The dissolved oxygen (DO), pH, water temperature, depth, and the relationship between numbers of autotrophs, Actinomycetes and fungi and odour intensity (OI) were measured. using statistical methods, the relationships between odour intensity and pH, OI and DO content were shown. By multiple regression OI in the Klicava water was found to be dependent on the concentration of DO and, to a lesser degree, on water depth. The effect of pH on OI is negligible. The Hubenov reservoir was studied for one year, with a view to the number of Actinomycetes in particular. A negative correlation between OI and DO in the surface water was found.

Density of the burrowing scorpion Urodacus armatus (Scorpiones; Scorpionidae) in relation to vegetation types: implications for population decline following agricultural clearing

1998 ◽  
Vol 4 (3) ◽  
pp. 209
Author(s):  
G. T. Smith
Keyword(s):  
Western Australia ◽  
Total Population ◽  
Nature Reserve ◽  
Vegetation Type ◽  
Population Decline ◽  
Vegetation Types ◽  
Before And After ◽  
Annual Cohort ◽  
The Relationship ◽  
Made In

The density of the burrowing scorpion Urodacus armatus in relation to vegetation type was assessed by counting the number of burrows, both the annual cohort of dispersing second instar and all older scorpions. The counts were made in 18 two metre wide transects across a 730 ha portion of Durokoppin Nature Reserve in the central wheatbelt of Western Australia. Densities were highest in woodlands (593/ha to 1950/ha), whereas in shrub and mallee associations densities were considerable lower (47/ha to 382/ha). Productivity, as measured by the ratio of second to older instar scorpions, ranged from 0.42 in low, open heath to 2.68 in Wandoo/Salmon Gum Eucalyptus capillosa/E. salmonophloia woodland. However, the correlation between productivity and the density of older scorpions in the vegetation associations was not significant. Total population in the study area was 254 954, of which 165 934 were second instar scorpions. Biomass estimates for second instar and older scorpions were 12 kg and 156 kg respectively. Observations throughout the wheatbelt indicated that the relationship between density and vegetation was comparable to that found in the study area. Using the data on the areas of the vegetation associations in the Avon Botanical District, before and after agricultural clearing (Beard and Sprenger 1984), and the densities in the present study, the abundance and biomass, pre- and post-clearing were calculated. The standing population (excluding the annual cohort) would have been of the order of 1.2 billion, with an annual influx of 2.6 billion. The biomasses would have been 690 tonnes and 210 tonnes respectively. Clearing reduced the area of habitat by 86% and the standing population by 92% and in woodland by 97%. The implications of these results for other species are discussed.

Deep Water Installation, Hydrodynamic Aspects and Practical Considerations

2014 ◽  
Author(s):  
Radboud van Dijk ◽  
Kees van Zandwijk ◽  
Eelco Harmsen
Keyword(s):  
Water Depth ◽  
Deep Water ◽  
State Of The Art ◽  
Extensive Experience ◽  
Sea Floor ◽  
Fast Growing ◽  
The Past ◽  
Pros And Cons ◽  
Made In

The past decade has shown a fast growing subsea production market tending to complete factories on the sea floor involving ever more complicated infrastructure and increasing size and weight components to be installed. The water depth of this market typically ranges between 1000 and 3000m. This new subsea market triggers a need for increased deep water lowering capacity to enable safe, fast and efficient installation of this infrastructure. The authors’ company has gained extensive experience in the field of deep water installation over the past 15 years, ranging from complex mooring foundations to the installation of large subsea production units in up to 3000m water depth. This experience is used and further deployed in the specification of new and higher capacity deep water lowering systems for recent and upcoming investments. The paper will share a number of the contractor’s considerations with respect to a state-of-the-art deep water lowering system meeting the needs of today’s subsea production market. The paper will address the challenges associated with the various stages of deep water installation, choices made in type of ropes (steel versus fiber), pros and cons of various floater types that can be used as an installation platform and the need for and effect of passive or active heave compensation.

Ship Springing Response in Finite Water Depth

2012 ◽  
Vol 56 (02) ◽  
pp. 80-90
Author(s):  
Jelena Vidic-Perunovic
Keyword(s):  
Relative Motion ◽  
Water Depth ◽  
Deep Water ◽  
Bending Moment ◽  
Intermediate Water ◽  
Short Term ◽  
Strip Theory ◽  
Influence Of Water ◽  
Finite Water Depth ◽  
Wave Induced

The influence of water depth on the vertical wave induced bending moment acting on a hull has been studied. The deep-water second-order nonlinear hydroelastic strip theory, which is based on the relative motion concept, has been generalized to account for a finite water depth. Results for an analytical beam and for a tanker ship are presented and discussed. Short-term load predictions that account for a range of different sea states are given for a tanker ship. As seen from the present study, the effect of intermediate water depth may be a significant factor in calculations of ship springing response.

Relationship between nerve blood flow and intercapillary distance in peripheral nerve edema

1986 ◽  
Vol 251 (1) ◽  
pp. E92-E97 ◽  
Author(s):  
P. G. McManis ◽  
P. A. Low ◽  
J. K. Yao
Keyword(s):  
Blood Flow ◽  
Peripheral Nerve ◽  
Computer Model ◽  
Nerve Blood Flow ◽  
Simultaneous Measurements ◽  
Intercapillary Distance ◽  
A Site ◽  
The Relationship ◽  
Endoneurial Edema ◽  
Made In

Some human and experimental neuropathies are characterized by endoneurial edema and increased intercapillary distance (ICD). This may potentially produce chronic endoneurial ischemia. To examine the relationship between nerve blood flow (NBF) and ICD we measured NBF in rats with experimental galactose neuropathy (EGN), a model where ICD is known to be increased. Simultaneous measurements of NBF in the center and subperineurial region were made in normal and edematous tibial nerves using hydrogen-sensitive microelectrodes and hydrogen polarography. NBF was significantly reduced in rats with EGN when compared with controls. A second finding was that in half the rats with EGN there was a greater reduction in NBF in the subperineurial region, a site of maximal ICD increase. In contrast, NBF was similar in central and peripheral regions in control rats. These findings support the hypothesis that an increase in ICD produces a reduction in NBF. Further support for the hypothesis is derived from a computer model of the effect of changes in ICD on endoneurial oxygen tension. We conclude that a chronic reduction in NBF may participate in the pathogenesis of edematous neuropathies.

Colonialism and the Highland Clearances

2017 ◽  
Vol 8 (1) ◽  
pp. 22-48 ◽  
Author(s):  
Iain Mackinnon
Keyword(s):  
Industrial Development ◽  
Comparative Approach ◽  
Indigenous Research ◽  
Internal Colonialism ◽  
New Approach ◽  
A Site ◽  
Relationship Of ◽  
The Relationship ◽  
Imperial State ◽  
Late Modern

This article employs a new approach to studying internal colonialism in northern Scotland during the 18th and 19th centuries. A common approach to examining internal colonial situations within modern state territories is to compare characteristics of the internal colonial situation with attested attributes of external colonial relations. Although this article does not reject the comparative approach, it seeks to avoid criticisms that this approach can be misleading by demonstrating that promoters and managers of projects involving land use change, territorial dispossession and industrial development in the late modern Gàidhealtachd consistently conceived of their work as projects of colonization. It further argues that the new social, cultural and political structures these projects imposed on the area's indigenous population correspond to those found in other colonial situations, and that racist and racialist attitudes towards Gaels of the time are typical of those in colonial situations during the period. The article concludes that the late modern Gàidhealtachd has been a site of internal colonization where the relationship of domination between colonizer and colonized is complex, longstanding and occurring within the imperial state. In doing so it demonstrates that the history and present of the Gaels of Scotland belongs within the ambit of an emerging indigenous research paradigm.

Wing lengths of Clamorous Reed Warblers Acrocephalus stentoreus in Israel

Ring ◽  
2004 ◽  
Vol 26 (2) ◽  
pp. 89-92
Author(s):  
John Morgan
Keyword(s):  
Wing Length ◽  
First Year ◽  
Comparable Data ◽  
Reed Warbler ◽  
Data Set ◽  
Acrocephalus Scirpaceus ◽  
Different Seasons ◽  
A Site ◽  
Made In ◽  
New Discovery

Wing lengths of Clamorous Reed Warblers Acrocephalus stentoreus in Israel Wing length measurements taken from first-year, pre- and post-moulting (annual, complete) Clamorous Reed Warblers were recorded at a site in northern Israel. The resulting data set was examined using a time-series of residuals (CUSUM). Results from this analysis can explain the reported heterogeneity found in a comparable data set by Merom et al. (1999). Further observations made in their paper are rebutted: (1) an implied assumption that Reed Warbler (Acrocephalus scirpaceus) spring migration in Israel ends by 1 May is contrary to other publications; (2) the late autumn occurence in N Israel of longer-winged 1st cal. yr. Reed Warblers, unconvincingly explained as either delayed migration by larger individuals or post fledging feather growth, is most likely due to birds from different provenances origins moving at different seasons; (3) growth during adulthood in Reed Warbler is not a new discovery, though presented as such.

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