scholarly journals How water level management affects cladoceran assemblages in lakes lateral to a reservoir

2016 ◽  
Vol 67 (12) ◽  
pp. 1853 ◽  
Author(s):  
José Roberto Debastiani-Júnior ◽  
Marcos Gomes Nogueira
Keyword(s):  
Steady State ◽  
Water Level ◽  
Submerged Macrophytes ◽  
Tropical Reservoir ◽  
Main River ◽  
River Reservoir ◽  
Continuous Application ◽  
Water Level Management ◽  
Loss Of Diversity ◽  
The Right

This study analysed the effects of induced water level depletion for macrophyte control in a tropical reservoir on the cladoceran fauna of two differentially connected lateral lakes. One lake, Pedra Branca, is located in the right margin and has a narrow connection to the main river–reservoir channel as well as a higher proportion of submerged macrophytes. On the opposite margin is Lake Guaritá, which is shallower and has a wider connection. Samples were collected over 16 consecutive months, including periods before, during and after depletion. Both lakes showed closely related trends in depth, pH, DO, conductivity, chlorophyll, temperature, suspended matter, phosphorus, nitrogen, silicate and ammonium variation, although a wider amplitude in variation was observed in Pedra Branca. This lake also had higher cladoceran diversity and a predominance of Chydoridae, whereas Bosminidae prevailed in Guaritá. Depletion caused a reduction in richness and an increase of Bosminidae in both lakes, although this was more pronounced in Pedra Branca. The management moderately affected both lakes but continuous application of this procedure may lead to a shift in the system steady-state and a loss of diversity that could be difficult to reverse.

Ecosystem development in Lake Volkerak-Zoom: concept and strategy

1995 ◽  
Vol 31 (8) ◽  
pp. 239-243 ◽  
Author(s):  
W. Ligtvoet ◽  
S. A. de Jong
Keyword(s):  
Water Level ◽  
Fish Stock ◽  
Ecosystem Development ◽  
Optimal Conditions ◽  
Stock Management ◽  
Key Factors ◽  
Integrated Water Management ◽  
Ecological Concepts ◽  
Freshwater System ◽  
Water Level Management

In the 6000 ha Lake Volkerak-Zoom, a new freshwater system in the estuarine southwest of The Netherlands, biomanipulation is used as a tool in ecosystem development. The basic ecological concepts for ecosystem development are described. Key factors in the integrated water management are fish stock management and water level management, geared towards creating optimal conditions for northern pike, the dominant predator in mesotrophic waters. The main aspects of the water level management and the fish stock management are outlined.

scholarly journals Reduced Visual Magnocellular Event-Related Potentials in Developmental Dyslexia

2021 ◽  
Vol 11 (1) ◽  
pp. 48
Author(s):  
John Stein
Keyword(s):  
Steady State ◽  
Developmental Dyslexia ◽  
Reading Ability ◽  
Event Related Potentials ◽  
Black And White ◽  
Reverse Pattern ◽  
Related Potentials ◽  
The Right ◽  
Visual Hemifields ◽  
Electroencephalogram Eeg

(1) Background—the magnocellular hypothesis proposes that impaired development of the visual timing systems in the brain that are mediated by magnocellular (M-) neurons is a major cause of dyslexia. Their function can now be assessed quite easily by analysing averaged visually evoked event-related potentials (VERPs) in the electroencephalogram (EEG). Such analysis might provide a useful, objective biomarker for diagnosing developmental dyslexia. (2) Methods—in adult dyslexics and normally reading controls, we recorded steady state VERPs, and their frequency content was computed using the fast Fourier transform. The visual stimulus was a black and white checker board whose checks reversed contrast every 100 ms. M- cells respond to this stimulus mainly at 10 Hz, whereas parvocells (P-) do so at 5 Hz. Left and right visual hemifields were stimulated separately in some subjects to see if there were latency differences between the M- inputs to the right vs. left hemispheres, and these were compared with the subjects’ handedness. (3) Results—Controls demonstrated a larger 10 Hz than 5 Hz fundamental peak in the spectra, whereas the dyslexics showed the reverse pattern. The ratio of subjects’ 10/5 Hz amplitudes predicted their reading ability. The latency of the 10 Hz peak was shorter during left than during right hemifield stimulation, and shorter in controls than in dyslexics. The latter correlated weakly with their handedness. (4) Conclusion—Steady state visual ERPs may conveniently be used to identify developmental dyslexia. However, due to the limited numbers of subjects in each sub-study, these results need confirmation.

Effects of the Belo Monte hydro-electric-dam complex on crocodilians in the Xingu River, Brazilian Amazonia

2021 ◽  
pp. 1-8
Author(s):  
Zilca Campos ◽  
Fábio Muniz ◽  
William E. Magnusson ◽  
Guilherme Mourão
Keyword(s):  
Water Level ◽  
Xingu River ◽  
Hydroelectric Dam ◽  
River Reservoir ◽  
Before And After ◽  
Collateral Effects ◽  
Generating Capacity ◽  
Reservoir Filling ◽  
Belo Monte

Abstract The Belo Monte hydroelectric dam on the Xingu River has the third largest generating capacity of any hydroelectric dam in the world. We conducted surveys of crocodilians (Caiman crocodilus, Paleosuchus trigonatus) by boat in the Xingu River at the site of the dam prior to (2013-2015), and after filling (2016-2017). While the number of C. crocodilus sighted decreased with increasing water level, there was no difference in numbers prior to, and after reservoir filling. The number of P. trigonatus was unaffected by both water level prior to and after reservoir filling. Reservoir filling had little effect on the number of crocodilians using the forest around the Xingu River reservoir. Most crocodilians seen in forest surveys were P. trigonatus, both before and after reservoir filling, but C. crocodilus was recorded occasionally in the forest. It seems that most Amazonian crocodilians are sufficiently generalist to adapt to the new conditions created by the construction of dams, at least in the short-term. However, there may be long-term collateral effects on crocodilian populations from dams, due to as deforestation and improved access for hunters.

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.

Abstract 89: The Ventriculo-Ventricular Coupling Index: A Novel Approach to Assessing Biventricular Function

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Navin K Kapur ◽  
Mark J Aronovitz ◽  
Robert Blanton ◽  
Emily Mackey ◽  
Vikram Paruchuri ◽  
...  
Keyword(s):  
Heart Failure ◽  
Steady State ◽  
Left Ventricular ◽  
External Jugular Vein ◽  
Arterial Elastance ◽  
Left Heart Failure ◽  
Novel Approach ◽  
Coupling Index ◽  
Ventricular Efficiency ◽  
The Right

Bi-ventricular (Bi-V) function in primary pulmonary hypertension (PPH) or PH secondary to left heart failure (SPH) remains difficult to characterize. As a measure of ventricular efficiency, ventriculo-arterial coupling (VAC) is calculated as the ratio of effective arterial elastance (Ea) to end-systolic elastance (Ees). No measure currently assesses ventriculo-ventricular coupling (VVC). Therefore, we developed a novel catheter-based approach to quantify Bi-V function using pressure-volume loop (PVL) analysis and hypothesized that Bi-V VAC ratios, defined as the VVC index (VVCI), may discriminate PPH and SPH. Methods: Adult male mice (n=6/group) underwent constriction of the pulmonary artery (PAC) or thoracic aorta (TAC) to model PPH and SPH respectively. Sham-operated animals underwent a left thoracotomy. Closed chest simultaneous Bi-V catheterization was performed after 7 days in PPH and 10 weeks in SPH. Conductance catheters were used for right and left ventricular PVL analysis via the right external jugular vein and right common carotid artery under steady-state conditions and with variable preload. Results: Steady-state Bi-V PVL and changes in VAC ratios and the VVCI are shown below. In sham mice VAC ratios and the VVCI reflect optimal ventricular efficiency. In PPH, the VVCI is significantly increased, while in SPH, the VVCI is significantly decreased compared to controls. Conclusion: These results identify a novel method to quantify Bi-V function in mice and further show that the VVCI can distinguish PPH and SPH. These findings have important implications for examining cardiac function in preclinical and clinical studies of left- and right-sided heart failure.

scholarly journals Contrasting Hydrodynamic Responses to Atmospheric Systems with Different Scales: Impact of Cold Fronts vs. That of a Hurricane

2020 ◽  
Vol 8 (12) ◽  
pp. 979
Author(s):  
Wei Huang ◽  
Chunyan Li
Keyword(s):  
Water Level ◽  
Cold Front ◽  
Volume Transport ◽  
Water Volume ◽  
Cold Fronts ◽  
Barataria Bay ◽  
Before And After ◽  
Frequent Exchange ◽  
The Right ◽  
Mexico Coast

In this paper, subtidal responses of Barataria Bay to an atmospheric cold front in 2014 and Hurricane Barry of 2019 are studied. The cold fronts had shorter influencing periods (1 to 3 days), while Hurricane Barry had a much longer influencing period (about 1 week). Wind direction usually changes from southern quadrants to northern quadrants before and after a cold front’s passage. For a hurricane making its landfall at the norther Gulf of Mexico coast, wind variation is dependent on the location relative to the location of landfall. Consequently, water level usually reaches a trough after the maximum cold front wind usually; while after the maximum wind during a hurricane, water level mostly has a surge, especially on the right-hand side of the hurricane. Water level variation induced by Hurricane Barry is about 3 times of that induced by a cold front event. Water volume flux also shows differences under these two weather types: the volume transport during Hurricane Barry was 4 times of that during a cold front. On the other hand, cold front events are much more frequent (30–40 times a year), and they lead to more frequent exchange between Barataria Bay and the coastal ocean.

Groundwater-surface water relations in regulated lowland catchments; hydrological and hydrochemical effects of a major change in surface water level management

2019 ◽  
Vol 660 ◽  
pp. 1317-1326 ◽  
Author(s):  
Joachim Rozemeijer ◽  
Janneke Klein ◽  
Dimmie Hendriks ◽  
Wiebe Borren ◽  
Maarten Ouboter ◽  
...  
Keyword(s):  
Surface Water ◽  
Water Level ◽  
Water Relations ◽  
Major Change ◽  
Water Level Management

Research of the Steady-State Modeling Method Based on Neural Network

2013 ◽  
Vol 441 ◽  
pp. 526-529
Author(s):  
Yu Hua Zhu ◽  
Dian Zheng Zhuang
Keyword(s):  
Neural Network ◽  
Steady State ◽  
Nitric Acid ◽  
Production Process ◽  
Acid Production ◽  
Actual System ◽  
Production History ◽  
System Input ◽  
Mechanism Modeling ◽  
The Right

Nitric acid production process is complicated reaction mechanism, serious non-linear the traditional mechanism modeling to get the low accuracy of the mathematical model. This paper adopts a non-mechanism modeling, using the production history data, the use of artificial neural network has the right to arbitrary nonlinear mapping any approximation ability to simulate the relationship of the actual system input-output, trained to be get steady-state model of the nitric acid production process.

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