Principles of designing secondary channels along the river rhine for the benefit of ecological restoration

1995 ◽  
Vol 31 (8) ◽  
pp. 379-382 ◽  
Author(s):  
M. H. I. Schropp
Keyword(s):  
Ecological Restoration ◽  
Threshold Value ◽  
Main Channel ◽  
River Rhine ◽  
Secondary Channel ◽  
Frequency Curve ◽  
Cross Sectional ◽  
Design Value ◽  
Ecological Targets ◽  
Flow Velocities

Secondary channels present a favourable opportunity for ecological restoration of the River Rhine and its branches. However, they have to be fitted into the landscape without affecting existing interests such as inland shipping and protection against flooding. Also the ecological targets have to be met with a minimum of human interference. In this article some design principles for secondary channels are presented in which these aspects are taken into account. To avoid silting up of the secondary channel it is recommended to prevent sediment from entering the channel at all. Flow velocities have to be below the threshold value for initiation of motion of sediment, but still high enough to satisfy the ecological targets. The secondary channel discharge is a function of the maximum allowable aggradation of the main channel. Discharge and flow velocities together determine the required cross-sectional area and thus the design value of the bank slopes. In order to have flowing water in the secondary channel all year round, the thalweg level is to be chosen on the basis of the water level frequency curve of the main channel.

scholarly journals Bathymetric components towards ensuring navigable channel along a section of lower river Niger, lokoja, kogi state, Nigeria

2021 ◽  
Vol 5 (5) ◽  
pp. 231-238
Author(s):  
Olanrewaju M Oye ◽  
Lawrence Hart ◽  
Sika Orupabo
Keyword(s):  
Flow Velocity ◽  
River Flow ◽  
Classical Method ◽  
Research Work ◽  
Economic Benefits ◽  
Main Channel ◽  
Secondary Channel ◽  
Cross Sectional ◽  
Single Beam ◽  
River Niger

Navigation in Lower River Niger is seasonal because of insufficient water depth during the dry season. This is a limitation to economic benefits derivable compared to when the river is navigable throughout the year. Government and stakeholders alike have exerted efforts in the past years to create an unimpeded navigable channel without much success. The need to ensure all-year-round navigation in the Lower River Niger for industrial and commercial purposes necessitated this research work. The main thrust of this work is to determine bathymetric components parameters of the river necessary for the design of an appropriate river training structure to divert river flow from the secondary channel to the main channel. The specific objective hereto is to assess the extent and geometry of the river banks, the configuration of the river bed, the river flow velocity and discharge. The approach deployed in this work is the classical method of acoustic principle premised on Remote Sensing techniques. The shape of the river was obtained through waypoint survey using Garmin eTrex 10 handheld GPS, while the riverbed configuration was determined through bathymetric survey using Odom Echotrack MK III single beam Echo Sounder and the flow velocity data was acquired using Valeport 106 Current Meter. Data processing and analysis were achieved using Garmin Basecamp 4.7.3, Wintopo V7.03, Valeport Datalog X2 and Surfer 13 software. The length of the study area measured along the main channel was obtained as 5.94km while that of secondary channel gave 4.30km. Area occupied by the main channel was found to be 2,636,331.3m2 and 1,759,045.4m2 for the secondary channel. Average depth on the main channel was 0.21m while on the secondary channel was -0.89m, depth figures referred to Lokoja local datum. The average flow velocity was obtained to be 0.449m/s and the cross-sectional area of the river as 1568.75m2, which gave a value of 704.2m3/s for the river discharge. The research produced the digital terrain model (DTM) and bathymetric charts of the study area. The parameters obtained in this study is a useful tool in defining an appropriate embankment dam suitable to divert the flow from the secondary channel to the main channel to enhance depth towards all-season navigation in Lower River Niger.

scholarly journals The δ subunit and NTPase HelD institute a two-pronged mechanism for RNA polymerase recycling

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Hao-Hong Pei ◽  
Tarek Hilal ◽  
Zhuo A. Chen ◽  
Yong-Heng Huang ◽  
Yuan Gao ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Nucleic Acids ◽  
Rna Polymerase ◽  
Active Site ◽  
Genome Stability ◽  
Slow Growth ◽  
Coiled Coil ◽  
Main Channel ◽  
Dependent Manner ◽  
Secondary Channel

AbstractCellular RNA polymerases (RNAPs) can become trapped on DNA or RNA, threatening genome stability and limiting free enzyme pools, but how RNAP recycling into active states is achieved remains elusive. In Bacillus subtilis, the RNAP δ subunit and NTPase HelD have been implicated in RNAP recycling. We structurally analyzed Bacillus subtilis RNAP-δ-HelD complexes. HelD has two long arms: a Gre cleavage factor-like coiled-coil inserts deep into the RNAP secondary channel, dismantling the active site and displacing RNA, while a unique helical protrusion inserts into the main channel, prying the β and β′ subunits apart and, aided by δ, dislodging DNA. RNAP is recycled when, after releasing trapped nucleic acids, HelD dissociates from the enzyme in an ATP-dependent manner. HelD abundance during slow growth and a dimeric (RNAP-δ-HelD)2 structure that resembles hibernating eukaryotic RNAP I suggest that HelD might also modulate active enzyme pools in response to cellular cues.

Pulsed Laser Melting of Amorphous Silicon: Time-Resolved and Post-Irradiation Studies

1983 ◽  
Vol 23 ◽  
Author(s):  
D. H. Lowndes ◽  
R. F. Wood ◽  
C. W. White ◽  
J. Narayan
Keyword(s):  
Pulsed Laser ◽  
Threshold Value ◽  
Dynamical Response ◽  
Cross Sectional ◽  
Time Resolved ◽  
Model Calculations ◽  
Fine Grained ◽  
Transmission Electron ◽  
Incident Laser Pulse ◽  
Thermal Melting

ABSTRACTMeasurements of the time of the onset of melting of self-implantation amorphized (a) Si, during an incident laser pulse, have been combined with modified melting model calculations and measurements of surface melt duration to demonstrate that the thermal conductivity, Ka, of a-Si is very low (≃0.02 W/cm-K). Ka is also shown to be the dominant parameter determining the dynamical response of ionimplanted Si to pulsed laser radiation; the latent heat and melting temperature of a-Si are relatively unimportant. Cross-sectional transmission electron micrographs on implantation-amorphized Si layers of several different thicknesses show that for energy densities less than the threshold value for complete annealing there are usually two distinct regions in the re-solidified a-Si, consisting of fine-grained and large-grained polycrystalline Si, respectively. The presence of the fine-grained poly-Si suggests that bulk nucleation occurs directly from the highly undercooled liquid phase. Thermal melting model calculations suggest that the nucleation temperature, Tn is ≃1200°C.

scholarly journals The Roles of Lumbar load thresholds in lifetime cumulative lifting exposure to predict disk protrusion

2019 ◽  
Author(s):  
Isabella Yu-Ju Hung ◽  
Tiffany Ting-Fang Shih ◽  
Bang-Bin Chen ◽  
Ing-Kang Ho ◽  
Saou-Hsing Liou ◽  
...  
Keyword(s):  
Final Analysis ◽  
Threshold Value ◽  
Cross Sectional Study ◽  
Optimal Threshold ◽  
Optimal Method ◽  
Cross Sectional ◽  
Women In The Workplace ◽  
Exposure Limit ◽  
Lifting Task ◽  
Lumbar Load

Abstract Background: The purpose of this study was to determine whether if a specific threshold value exists in each lifting load, the accumulation above which best predicts lumbar disk protrusion, or on the other hand, all lifting load should be accumulated. Methods: This was a cross-sectional study. Subjects with various lifetime lifting exposures were recruited. Disk protrusion was determined by magnetic resonance imaging. Lifetime cumulative lifting load was the sum of time-weighed lumbar load for each job using a biomechanical software system. For accumulation above different thresholds, predictive capabilities for disk protrusion were compared using four statistical methods. Results: A total of 252 men and 301 women were included in the final analysis. For men, 3000 Newton for each lifting task was the optimal threshold value for predicting L4-S1 disk protrusion, whereas for women, 2800 Newton was optimal. Our findings suggested that when considering lifetime exposure, including all lifting loads without defining a minimal exposure limit might not be the optimal method for predicting disk protrusion. Conclusions: The NIOSH 3400 Newton recommended limits do not appear to be optimal threshold for preventing disk protrusion. Different lifting thresholds might be applied to men and women in the workplace for safety.

An energy charge sensor for balancing RNA polymerase recycling and hibernation

2020 ◽  
Author(s):  
Markus Wahl ◽  
Hao-Hong Pei ◽  
Tarek Hilal ◽  
Zhuo Chen ◽  
Yong-Heng Huang ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Active Site ◽  
Genome Stability ◽  
Energy Levels ◽  
Energy Charge ◽  
Coiled Coil ◽  
Main Channel ◽  
Rna Polymerase I ◽  
Secondary Channel ◽  
Polymerase I

Abstract Cellular RNA polymerases can become trapped on DNA or RNA, threatening genome stability and limiting free enzyme pools, or enter dormancy. How RNA polymerase recycling into active states is achieved and balanced with quiescence remains elusive. We structurally analyzed Bacillus subtilis RNA polymerase bound to the NTPase HelD. HelD has two long arms: a Gre cleavage factor-like coiled-coil inserts deep into the RNA polymerase secondary channel, dismantling the active site and displacing RNA; a unique helical protrusion inserts into the main channel, prying β and β’ subunits apart and dislodging DNA, aided by the δ subunit. HelD release depends on ATP, and a dimeric structure resembling hibernating RNA polymerase I suggests that HelD can induce dormancy at low energy levels. Our results reveal an ingenious mechanism by which active RNA polymerase pools are adjusted in response to the nutritional state.

scholarly journals On-Chip Multiple Particle Velocity and Size Measurement Using Single-Shot Two-Wavelength Differential Image Analysis

Micromachines ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1011
Author(s):  
Shuya Sawa ◽  
Mitsuru Sentoku ◽  
Kenji Yasuda
Keyword(s):  
Irradiation Time ◽  
Single Shot ◽  
Cross Sectional ◽  
Simple Method ◽  
Quick Measurement ◽  
The Difference ◽  
On Chip ◽  
Calculated Velocity ◽  
Multiple Particle ◽  
Flow Velocities

Precise and quick measurement of samples’ flow velocities is essential for cell sorting timing control and reconstruction of acquired image-analyzed data. We developed a simple technique for the single-shot measurement of flow velocities of particles simultaneously in a microfluidic pathway. The speed was calculated from the difference in the particles’ elongation in an acquired image that appeared when two wavelengths of light with different irradiation times were applied. We ran microparticles through an imaging flow cytometer and irradiated two wavelengths of light with different irradiation times simultaneously to those particles. The mixture of the two wavelength transmitted lights was divided into two wavelengths, and the images of the same microparticles for each wavelength were acquired in a single shot. We estimated the velocity from the difference of its elongation divided by the difference of irradiation time by comparing these two images. The distribution of polystyrene beads’ velocity was parabolic and highest at the center of the flow channel, consistent with the expected velocity distribution of the laminar flow. Applying the calculated velocity, we also restored the accurate shapes and cross-sectional areas of particles in the images, indicating this simple method for improving of imaging flow cytometry and cell sorter for diagnostic screening of circulating tumor cells.

Effect of Western the Fourth Phase Project on Hydrodynamic Condition for Shijiu Port in Rizhao

2012 ◽  
Vol 204-208 ◽  
pp. 2369-2373
Author(s):  
Jia Rui Li ◽  
Die Shuang Yu
Keyword(s):  
Channel Flow ◽  
Water Area ◽  
Main Channel ◽  
Hydrodynamic Condition ◽  
Port Area ◽  
Before And After ◽  
Project Construction ◽  
Sheltering Effect ◽  
Sea Area ◽  
Flow Velocities

A hydrodynamic model of Shijiu port and its adjacent sea area was built to discuss the effect of western the fourth phase project on the flow condition for Shijiu port area. The results show that with the sheltering effect of breakwaters, flow velocity values are small inside the breakwaters. The water area near the project is affected more by the project construction. The flow velocities there are faster after the project construction than before it. In the main channel, flow velocities outside the breakwaters almost have no difference before and after the project. The project construction doesn’t have significant effect on it.

Elevated Circulating Levels of Carnal ENST00000550337.1 Are Associated with Polycystic Ovary Syndrome in Chinese Women

2021 ◽  
pp. 1-7
Author(s):  
Yujuan Qi ◽  
Qianqian Yin ◽  
Juan Gu ◽  
Ying Liu ◽  
Qingqing Sun ◽  
...  
Keyword(s):  
Polycystic Ovary Syndrome ◽  
Peripheral Blood ◽  
Noncoding Rna ◽  
Chinese Women ◽  
Polycystic Ovary ◽  
Threshold Value ◽  
Expression Level ◽  
Ovary Syndrome ◽  
Blood Leukocytes ◽  
Cross Sectional

Objectives: Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disease. Some studies reported that the development of PCOS may be closely related to insulin resistance (IR). Interestingly, the long noncoding RNA (lncRNA) ENST00000550337.1 in peripheral blood is mainly involved in glucose metabolism. Therefore, the purpose of our study was to explore the relationship between lncRNA ENST00000550337.1 level and PCOS patients. Materials and Methods: Seventy-five PCOS patients and 72 healthy controls were enrolled in this study. We used qRT-PCR to detect the expression level of lncRNA ENST00000550337.1 in peripheral blood leukocytes from patients with PCOS. We also investigated potential relationships between lncRNA ENST00000550337.1 and the endocrine parameters in PCOS. Results: We observed that the expression of lncRNA ENST00000550337.1 in PCOS patients was significantly higher than that in the control subjects and positively correlated with PCOS occurrence, waist circumference, waist-hip ratio, IR, fasting insulin levels, and blood glucose. The expression of lnc RNA ENST00000550337.1 was positively correlated with PCOS (p = 0.003). There were independent correlations between IR and expression of lncRNA ENST00000550337.1 in patients with PCOS. Patients with elevated lncRNA ENST00000550337.1 expression had significantly increased PCOS risk after adjusting for age and BMI. LncRNA ENST00000550337.1 expression level provided a sensitivity of 81.3% and a specificity of 78.1% with a threshold value of 6.4648 for the prediction of PCOS. The area under the ROC was 0.813. Limitations: There are some limitations to this study. First, the sample size was limited and the causal relationship between lncRNA ENST00000550337.1 and PCOS was not investigated due to the cross-sectional study design. Second, HOMA-IR does not fully accurately reflect the IR of patients. Conclusions: The present study indicated that lnc RNA ENST00000550337.1 was related to PCOS occurrence, and elevated levels may be a risk factor for PCOS women. In addition, lncRNA ENST00000550337.1 might promote PCOS development partially by increasing IR and can be used as a potential molecular marker in patients with PCOS.

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